US20040193181A1 - Active cannulas - Google Patents

Abstract

An active cannula which does more than merely maintain a passage is usable to create and/or enlarge a passage, to position a scope or instrument, to move or locate tissue, etc. The cannula can vary in size or shape as needed, intraoperatively. Because a cannula of the present invention is expandable, the surgeon can make a relatively small incision, stretch the tissue with the expandable cannula, contract the cannula and remove it, allowing the skin to come back to its unstretched condition. Thus, a smaller incision can be made to fit the same size instrument. The cannulas can assume such a non-circular shape, to fit into a natural skin opening and cause less trauma. The devices can be used to seal off a space, expand an existing space or a potential space for working or visualization, move tissue (for example, to stretch an incision), or protect tissue.

Description

RELATED APPLICATIONS
• This application is a continuation of co-pending U.S. application Ser. No. 10/099,265 filed Mar. 14, 2002 which is a continuation of U.S. application Ser. No. 08/727,968 filed on Oct. 9, 1996, now U.S. Pat. No. 6,358,266, which is a divisional of U.S. application Ser. No. 08/462,420, filed on Jun. 5, 1995, now U.S. Pat. No. 6,171,299, which is a divisional of U.S. application Ser. No. 08/195,337, filed on Feb. 14, 1994, now U.S. Pat. No. 5,514,153, which is a continuation-in-part of U.S. application Ser. No. 07/792,730, filed on Nov. 15, 1991, now U.S. Pat. No. 5,295,994, and a continuation-in-part of U.S. application Ser. No. 08/054,416, filed on Apr. 28, 1993, now abandoned, which is a divisional of U.S. application Ser. No. 07/487,645 filed on Mar. 2, 1990, now U.S. Pat. No. 5,331,975. The benefit of the earlier filing date of aforementioned applications is hereby claimed. The specifications of the aforementioned applications are hereby fully and expressly incorporated by reference herein.[0001]
BACKGROUND OF THE INVENTION
• The present invention relates to medical devices, and particularly to expandable medical devices such as cannulas, catheters, retractors, and similar devices.[0002]
• Existing cannulas and/or retractors as used in endoscopic surgery today are passive devices which are fixed in length and width. They cannot be varied intraoperatively in length and width to accommodate larger devices or varying size devices through the skin.[0003]
• Skin and subcutaneous (subsurface) tissues are viscoelastic: they will gradually stretch without tearing. Once the tissue is slowly stretched it maintains its expanded condition for a period of time. Alternatively, the tissue can be stretched further, for example to progressively stretch out an incision. Then, after relaxation, the tissue will regain its original unstretched condition without having been damaged.[0004]
• Current methods used for retracting tissue and improving visualization are mechanical separation using metal refractors during open surgery, or the direct pressure of an unconfined flow of fluid such as water or CO[0005]₂during fiberoptic surgery. A typical mechanical external fixator has pins driven through the bones and mechanically distracts the elements of the joint. Problems with the water method include fluid extravasation including into and through the tissue itself. Increased pressure and swelling result in the area, resulting in edematous or swollen tissue. Excess pressure from mechanical refractors may cause necrosis or tissue death. With these methods, it is impossible to monitor the pressure being applied to the body tissues, and tissue damage or necrosis can result.
• While operating from within the body, i.e., fiber optic assisted surgery as opposed to open surgery, there is no known way to selectively move or retract tissue, either hard tissue such as bone or soft tissue, out of the way to improve visualization. No device in use adequately allows a surgeon to create an actual space or expand a potential space in the body, by separating adjacent layers of tissue. The prior art does not disclose a retractor which is powerful enough and made of a material which is strong and resilient enough to, for example, separate tissue planes from within. Such a device, especially in the field of fiber optic surgery, would allow a surgeon to visualize and operate without using the conventional bulky and awkward mechanical Detractors which require large open incisions. Such a device would also permit working within the body without damaging a great deal of tissue in the path between the skin opening and the working area, by minimizing the external orifice or skin incision.[0006]
SUMMARY OF THE INVENTION
• The present invention is a system of refractors and/or cannulas with which a surgeon can use to take potential spaces within the body and turn them into existing spaces safely and easily and controllably in order to safely visualize appropriate tissue and operate. The cannula and/or retractor selectively moves appropriate tissue out of the way to enable a surgeon to see and work better within the body, and selectively moves body parts such as joint parts or soft tissue planes in order to create a space between the tissues for visualization and for working.[0007]
• A cannula and/or retractor of the present invention may have a fluid-operated portion such as a balloon or bladder to retract tissue, not merely to work in or dilate an existing opening as for example an angioscope does. The fluid-filled portion is flexible, and thus there are no sharp edges which might injure tissue being moved by the retractor. The soft material of the fluid-filled portion, to an extent desired, conforms to the tissue confines, and the exact pressure can be monitored so as not to damage tissue. The expanding portion is less bulky and more compact, and the pressure it applies at the tissue edges can stop bleeding of cut tissue. These are all features not possessed by a conventional mechanical retractor.[0008]
• With a typical mechanical retractor, the opening in the skin and thence inwardly must be larger than the surgical area being worked upon, in order to be able to get the mechanical retractor into position. The surgeon must damage a large amount of tissue which may be healthy, in order to expose the tissue to be worked on. The cannula and/or retractor of the present invention minimizes damage to tissue in the way of the tissue the surgeon needs to expose, which was previously cut in a large open exposure. With the cannula and/or retractor of the present invention, the opening at the skin is smaller at the skin where the device is inserted, and wider at the location inside the body where the cannula and/or retractor is expanded. The cannula and/or retractor is first placed into the body in an unexpanded condition, and then, as it is expanded, pushes tissue out of the way in deeper layers of the body one can see and safely operate on affected tissue. Thus, less undesired tissue damage occurs.[0009]
• The bladder is pressurized with air or with water or another fluid. The fluid used in the bladder must be safe if it accidentally escapes into the body. Thus, besides air, such other fluids as dextrose water, normal saline, CO[0010]₂and N₂are safe. The pressure in the bladder is monitored and regulated to keep the force exerted by the retractor at a safe level for tissue to prevent tissue necrosis. The retractor can exert a pressure on the tissues of as high as the mean diastolic pressure of 100 mm of mercury, or higher for shorter periods of time, while still being safely controlled. Typical inflatable devices such as angioscopes do not have anywhere near the strength, or the ability to hold enough fluid pressure, or shapes to retract tissue as described herein. As compared to prior art devices, the retractor of the present invention operates with greater pressure within the bladder, since it is made of stronger materials such as Kevlar or Mylar which may be reinforced with stainless steel, nylon, or other fiber to prevent puncturing and to provide structural shape and support as desired. Such materials are strong enough to hold the necessary fluid pressure of about several pounds or up to about 500 mg Hg or more and exert the needed force on the tissue to be moved. The choice of material is well within the ability of one familiar with such materials and accordingly will not be gone into in further detail herein. The present retractor is thus able to exert substantially more force on adjoining tissues than a prior art device. The shapes of the refractors are specific for each application, and may include separate variable chambers which are sequentially controllable, to control the direction of tissue retraction.
• Surgeons operate along tissue planes. Once a surgeon finds a tissue plane, he dissects along it, starting the separation process with the knife. The cannula and/or retractor holds the tissue layers apart and helps and eases in defining and further separating the tissue layers as the surgeon operates along the tissue planes, helping to spread and define the planes. The cannula and/or retractor helps to separate the tissue layers, increasing the space for operating, and improving the surgeon's ability to separate and visualize, leading to better and safer surgical technique.[0011]
• A preferred use for the present retractor is in the field of fiber optic surgery, including endoscopy, arthroscopy, laparoscopy, etc. which require looking into and operating within a limited space with a fiber optic light and camera. The bladder expands into an area of soft tissue—for example the bursa—and pushes it out of the way. The bladder can be left in place during the operation, or it can be deflated and removed, and the arthroscope and other instruments can be put into the space created.[0012]
• The bladder may be a bellows type device in which the material does not stretch but which expands when pressurized from within and which is collapsed by the use of suction. In this case, it would preferably be made of a polymer of the class including Kevlar or Mylar fabric for strength and structural integrity. The bladder may generally also be made from any very thin walled polymer.[0013]
• The bladder may also be made from a biocompatible and/or biodegradable material, so that if it can not be removed from the body for some reason, or if the surgeon desires to keep the bladder in place in the body for a period of time, it will not damage the tissue and may eventually be reabsorbed into the body. Such a biodegradable bladder may be left under the skin post-operatively to stop postoperative bleeding or to keep tissue expanded. Alternatively, the bladder may be made of a stretchable material which stretches when pressurized from within, and then collapses partially of its own accord when depressurized or also with the help of suction. The retractor may be transparent for better visibility, but it need not be for some applications. Also, the retractor can be disposable. The material choice is within the skill of the art. One surface of the bladder may be made of or have thereon a reflective surface to reflect light to see around a corner.[0014]
• A most typical construction for the cannula and/or retractor of the present invention is an inflatable bladder situated on the end of a shaft, which may be flexible or rigid,—which is pushed through an extra opening in a scope or cannula or through a separate portal, and which expands at the end of the shaft.[0015]
• The retractor can be located on a scope, either on the end thereof or movable axially through a channel along the length of the scope. The retractor can alternatively be mounted on a cannula. The retractor can be mounted on a separate shaft passing through an existing channel in a cannula; it can be inserted through a separate hole in the cannula or the scope; or it can be inserted through a separate opening in the body. The shaft with a retractor on the end can be pushed or slid through the cannula, side by side with a scope. Alternatively, the bladder can expand out of, then recess back into, a groove on a cannula or scope. The retractor can be used to create a space right by the scope, or possibly at a location spaced from the end of the scope.[0016]
• The bladder itself can be round, eccentric, oval, conical, wedge-shaped, U-shaped, curved, angled, or it may be in any shape desirable to optimize the particular application. The bladder may be irregularly shaped when inflated, that is, it may expand to a greater radius in the area where it is desired to look (where greater exposure space is needed).[0017]
• Vacuum can be used to deflate the bladder. The bladder may then be removed by sliding it out the portal directly.[0018]
• The present invention is described herein as relating to cannulas and/or refractors. A cannula is a device for insertion into or through body tissue to provide a working passage for surgical instruments, scopes, etc., as in endoscopic or arthroscopic surgery. A catheter, on the other hand, is an artificial fluid passage primarily used for insertion through an existing body opening. The two types of devices have very different structures and structural requirements. For example, a catheter is usually flexible, very small in diameter, and not suitable for maintaining a working passage through normally closed body tissues, while a cannula is more rigid, larger in size, and designed specifically to provide a working passage for surgical instruments and scopes through normally closed body tissues. It should be understood, however, that many of the features of the present invention can with suitable modifications be applied to the catheter art. Accordingly, the present invention is not limited to cannulas per se, but may be applicable to catheters or other devices also.[0019]
• The present invention defines an active cannula or sleeve which does more than merely maintain a channel or passage. It is an active device usable to enlarge a channel or passage, to position a scope or instrument, to move or locate tissue, etc. The cannula can vary in size or shape as needed, intraoperatively. Typically, with a passive (non-expandable) cannula, a surgeon must make an incision in the skin and muscle large enough to receive the largest instrument to be passed through the incision to the surgical area. Because a cannula of the present invention is expandable, the surgeon can make a small relatively small incision, stretch the tissue with the expandable cannula, contract the cannula and remove it, allowing the skin to come back to its unstretched condition. Thus, a smaller incision can be made to fit the same size instrument. This results in less trauma and scarring and an easier operation.[0020]
• Further, known cannulas are generally round, while skin expands (from an incision) in an elliptical fashion, between tissue planes. Thus, the present invention provides cannulas which are or can assume such a noncircular shape, to fit into the natural opening and cause less trauma.[0021]
• The devices of the present invention are usable in endoscopic procedures generally. The devices can be used to seal off a space; to expand an existing space or a potential space for working or visualization; to move tissue (for example, to stretch an incision) or to protect it. Other uses within the skill of the art but not enumerated herein are within the scope of the invention.[0022]
• The cannulas of the present invention allow for the progressive stretching of an incision in skin or subsurface tissue in order to allow improved exposure, while minimizing damage to the tissue by making the actual incision as small as possible.[0023]
• In the arthroscopic model, a fixed cannula is placed through the skin to the subsurface tissues into a joint. Different size working devices (shavers, burrs, scissors, punches, scope, etc.) are placed through the cannula to visualize or to work in the subsurface area at the distal end of the cannula. The cannula can be progressively expanded or stretched radially outwardly, to stretch or expand the skin and subsurface tissues. The cannula typically expands along its entire length, although it may in some cases be expandable at selected portions along its length.[0024]
• The expansion can be in a circular pattern, or it can be in an oval or elliptical or other pattern to accommodate (a) the tissue planes or (b) the instruments being inserted through the cannula.[0025]
• The cannula can expand inwardly to act like a valve or a seal. Or it can expand both inward and outward.[0026]
• The cannula is preferably flexible—that is, it is bendable about an axis extending perpendicular to the longitudinal extent of the cannula. In other words, the cannula as a long straight object is not rigid but can bend so that it is not straight. This allows the cannula to conform to the body tissues to the extent desired.[0027]
• All cannula bodies can be multi-lumen for passages through which extend structure for control of bladders, tools, scope, etc.[0028]
• In a first embodiment, a cannula may be of a stretchable material (such as a polymer) which is introduced into the body with a trocar. The trocar is then removed. Progressively larger dilating devices are placed inside the stretchable cannula, as needed, to progressively stretch out the skin and tissue to a larger size in order to introduce larger instruments through the cannula. Each time the cannula is enlarged, the stretched tissue-remains in its stretched condition for a period of time because of its viscoelastic properties.[0029]
• One way of stretching the cannula is by placing inside the stretchable cannula a bladder (round or elongated in the shape of a sausage, for example) which can be inflated to uniformly stretch the cannula and tissue. The bladder can be deflated and removed, leaving the enlarged opening.[0030]
• In a second embodiment, the cannula is itself inflatable for expansion. The cannula is basically an inflatable cylinder with expansions in both the inner diameter and the outer diameter. As inflated, the device expands to a preformed shape with the inner diameter following the outer diameter and expanding outward to create a progressively larger opening. Filaments or cords can be-placed between the inner and outer walls to limit their separation from each other. The inner wall can be more rigid.[0031]
• In a third embodiment, the cannula includes one or more stretchable (inflatable or expandable) parts and one or more non-stretchable parts. The non-stretchable parts can be metal or plastic pieces such as curved plates, joined by the stretchable elements which extend longitudinally between them. These stretchable elements can be bladders. As larger devices are passed through the cannula, the stretchable portions expand and the plates move outwardly to stretch an-appropriate opening.[0032]
• In any of these cases, one can monitor and control the amount of pressure being applied to the tissue upon expansion of the cannula, so as to not exceed a certain critical pressure and damage tissue. This can be done by monitoring the actual size of expansion, the amount of air or fluid introduced to inflate the device, the fluid pressure within the device, etc.[0033]
• There are numerous possibilities of a cannula-with-bladder or (catheter-with-bladder) construct.[0034]
• One specific example is an arthritis irrigation system. This is a multi-lumen tube which has one lumen/portal for inflow of irrigation fluid and a second portal for suction (return). The tube is flexible and has its distal end placed in a joint to be irrigated. The tube is fixed in place by an expanding device as discussed below. Fluid flowing through the joint flushes out debris in the joint. The device can include third or additional lumens for a scope or tools to pass through. Since the tube is both flexible and fixed in place, it can remain in the patient even when the patient is ambulatory. It thus provides a permanent passage for the surgeon to access the joint.[0035]
• There can be multiple bladders at a location on the cannula, independently controlled, to position the cannula. At least one bladder is preferably at the tip of the device to expand or stretch tissue or to stabilize the device.[0036]
• In any of the illustrated embodiments, the bladder can be made of a different material from the cannula, as opposed to, for example, a Fogarty catheter which is made of all one material. This will allow for variations in construction, with the bladder being made of one material to better perform its functions and the cannula or other supporting member being made of another material to better perform its functions.[0037]
• The expanding (inflatable) bladders of the present invention are constructed in various manners as set forth below. The bladder can stretch cannula walls. The bladder can move tissue and allow selective manipulation of tissue, even arthroscopically. The bladder also has a tamponade effect, lessening bleeding in the surrounding tissues.[0038]
• The bladder also distributes the refractive force, reducing stress on delicate tissues such as nerve tissue.[0039]
• There can be one or more bladders at any given location or on any given instrument. Multiple bladders can be controlled as independent structures or as one unit. Specific structure and control is based on the particular application.[0040]
• The surface of the material can be pebbled or roughened or ridged, or have serrated edges, to better grip tissue and hold the retractor in position. Of course, the surface must still remain smooth enough so that the retractor is easily removable without damage to the tissue it contacts.[0041]
• The bladders can expand by well in excess of 200%.[0042]
• The bladder is preferably made of an elastomeric material which is strong-enough to move tissue as desired. A suitable material for the expandable bladder is Silastic® elastomer, which is available from Dow Coming in medical grades. Other suitable materials are silicone, or latex, or PVC.[0043]
• The bladder may be made of a non-elastomeric material which is strong enough to move tissue as desired. A suitable material is Mylar® fabric. A non-elastomeric material may have a more controllable shape because it will not stretch. A non-elastomeric material will collapse inward automatically due to the pressure of the tissue around it, whenever it is not inflated. Many of the illustrated embodiments which are discussed as being made of an elastomeric material can also be made of a nonelastomeric material.[0044]
• The expandable bladder can be made of a biodegradable material. In such a case, the biodegradable portion can be made detachable from the remainder of the retractor, so that it can be detached and left in the body after surgery. This is useful, for example, to prevent adjacent tissue planes from scarring together after surgery. The biodegradable mass will in time disappear, allowing the tissues to adjoin after they are healed.[0045]
• The bladder can be made of a composite material—that is, a particle or fiber-reinforced material. Many suitable materials are in use in industry. Composite materials can be made stronger while still retaining flexibility and fluid-sealing capabilities. Composite materials also provide the capability to have a bladder assume a specific shape upon expansion.[0046]
• The bladder can be made of a composite biodegradable material.[0047]
• The bladder(s) can be made of two different materials bonded together, such as a stretchable (low-modulus) and a non-stretchable (high-modulus) material. Mylar® and Silastic® are suitable materials, or metal for a stiff material. As the inflation fluid (typically air) is introduced, it takes the path of least resistance—and the non-stretchable material fills out to its expanded shape first. Then the stretchable material expands, in a manner constrained by the already-expanded non-stretchable material.[0048]
• The bladder can be made of a transparent material to provide a better view of the operating area and improved visualization.[0049]
• The bladder may have a dual durometer layered construction, with a thin layer for fluid retention overlying a thicker layer for shaping. Other laminated constructions are possible, also.[0050]
• The external shape of—the retractor when expanded, and the amount of expansion, are designed for the specific application on which that retractor is to be used. For example, if the surgeon is working against bone, he can select a retractor which is configured so that it stays flat against the bone, and expands away in the opposite direction, to push tissue away from the bone and create a working and visualization space next to the surface of the bone.[0051]
• There are several ways to control shape of expansion-thick and thin areas (gaps, ridges, stiffened areas, etc.), fiber reinforcing, dual durometer construction, different materials affixed together, tethering cords, and pre-shaping.[0052]
• Upon application of a given amount of force, a thinner material will stretch more than a thicker material. Thus, all other factors being equal, an inflatable device will stretch more where it is thinner, and will stretch less where it is thicker. This occurrence can be used to control the shape into which a bladder expands when it is inflated by fluid under pressure.[0053]
• As a simple example, it can readily be seen that if a bladder has one half made of a very thick material and one half made of the same material but much thinner, then upon the introduction of fluid under pressure, the thin material will stretch more quickly (easily), and the bladder will expand unevenly. The thin half of the bladder will deform more under the same pressure until the force needed to stretch it further is equal to the force needed to stretch the thicker material. The half made of the thicker material will then begin to stretch, also. Thus, the thickest point on the wall will be at the crown area (farthest out).[0054]
• The areas of variation in cross section can be of various shapes and directions to control the expansion rates. For example, the circumference of a bladder can be configured as an incomplete hoop. Thus, most of the circumference is of a thicker material, while selected areas are thinner. Upon the introduction of fluid under pressure, the thinner areas will expand first, with each thicker area moving outwardly as a whole.[0055]
• There can be ribs around the circumference. Areas of thickness or thinness can extend longitudinally, circumferentially, radially, or in broken segments.[0056]
• A second way to control the shape of expansion is the use of a fiber reinforced (composite) material. The direction of the fibers, along with their number, spacing, layering, and length, controls the rate of expansion of the matrix material. Also, areas devoid of fibers will expand faster or further than areas with more or stiffer fibers.[0057]
• Specifically, the fibers resist stretching along their length. Thus, the bladder will stretch more in a direction across the fibers, or where the fibers are not present, than in a direction along the fibers. Fibers can be placed at the edge of the bladder to maintain the shape of the bladder when inflated. Fibers can be layered, with one layer in one direction and another layer in another direction to control expansion in the other direction. Fibers can be placed in overlapping layers, to allow expansion in one plane only.[0058]
• Adding fibers makes the bladder more puncture and tear resistant. Note that the bladder can, for this purpose, also be made of or include a self-sealing material.[0059]
• A third way of controlling expansion shape is to preshape the bladder to assume a certain form when expanded. This is done in the molding process. The bladder is typically formed on a mandrel which is of a particular shape and which is sized about half way between the unexpanded and the expanded size of the bladder.[0060]
• The pre-determined shape of the unexpanded bladder is basically a combination of varying wall thickness and ribbing, made on a three part mold.[0061]
• In certain experimental models constructed to date, the bladder is bonded onto a nylon stalk of 7 mm O.D. The bladder is stretched from about 3 mm to about 7 mm at its smallest dimension. This pre-stretched area puts the material under tension. Any larger diameter portions are relaxed. As the bladder is expanded, the smaller diameter portion, which is already partially expanded, stretches at a limited rate. The larger diameter portion (under no load) expands at a faster rate. They balance out at a point where all the material is under basically the same load in tension. This is the point at which the shape is attained.[0062]
• It should be understood that this particular example and its dimensions are not limiting, and that any diameter can be used. This is an example of a specific sized cannula for a specific application.[0063]
• With a typical material (silicone), the more you stretch the material, the more force is needed to stretch it further.[0064]
• The prestretching of the bladder is done so that the bladder lies flat on the cannula body. The bonding areas are such that as the expansion takes place the material expands radially outwardly as well as axially.[0065]
• It can alternately be doubled up at a certain area, such as the tip of a stalk or cannula. This will allow maximum expansion at the tip.[0066]
• Tethering cords can be fixed to bladder portions and extend between them to control and/or limit the expansion of the bladder. This can be done with bladders made of a composite material or including plates or other thicker areas. In a cannula construct, the tethering cords can run between the cannula body to the crown of the bladder to control and/or limit its expansion.[0067]
• Plates can be added in which will limit the shape of the bladder or create an edge. For example, if a flat plate is added, the bladder can expand in a circular fashion but the flat plate will remain flat and provide a flat area on the outside of the bladder. Or the plate can be circular, or at an angle to create an edge. There can be multiple such plates added to create specific shapes. Tethering cords can be used to extend to the plate. This can be useful in the cannula construct.[0068]
• The bladder can also have a bellows-type construction for increased expansion control and structural rigidity.[0069]
• Suction can be used to collapse any of the devices to facilitate removal.[0070]
BRIEF DESCRIPTION OF THE DRAWINGS
• The foregoing and other features of the present invention will become apparent to one skilled in the art upon a consideration of the following description of the invention with reference to the accompanying drawings, wherein:[0071]
• FIG. 1 is a side elevational view of a joint irrigation apparatus;[0072]
• FIG. 2 is a longitudinal sectional view through the apparatus of FIG. 1;[0073]
• FIG. 3 is a view taken along line[0074]3-3 of FIG. 1;
• FIG. 4 is a view of an alternate embodiment of the apparatus of FIG. 1;[0075]
• FIG. 5 is a transverse sectional view through an expanding cannula;[0076]
• FIG. 6 is a view of the cannula of FIG. 5 in an expanded condition;[0077]
• FIG. 7 illustrates a cannula having an outwardly expanding bladder formed within the wall of the cannula;[0078]
• FIG. 8 illustrates a cannula having an inwardly expandable bladder formed in the wall of the cannula; FIG. 9 illustrates a cannula having an inwardly and outwardly expanding bladder formed within the wall of the cannula;[0079]
• FIG. 10 illustrates the expansion of a cannula having viscoelastic walls by means of an inserted inflatable member;[0080]
• FIGS. 11-13 illustrate a cannula comprising a cylinder expandable along its entire length;[0081]
• FIG. 14 illustrates an elliptical or an oval-shaped cannula having tethering cords;[0082]
• FIG. 15 illustrates a square-shaped cannula having tethering cords;[0083]
• FIG. 16 is a schematic view of a retractor shown in the unexpanded or contracted and expanded or extended conditions;[0084]
• FIG. 17 is a schematic view of a retractor extending through a cannula and mounted on the end of a separate shaft;[0085]
• FIG. 18 is a schematic view similar to FIG. 17 illustrating the use of a fiber optic scope with the retractor;[0086]
• FIG. 19 is a schematic view showing a retractor inserted through a separate side opening in a cannula;[0087]
• FIG. 20 is a schematic view of a few of the many and various shapes in which the inflatable portion of the retractor may be formed;[0088]
• FIG. 21 is a schematic view of a retractor shown mounted on the end of a cannula and having an opening therein for a scope to pass through;[0089]
• FIG. 22 is a diagram of a fluid supply system for operating a retractor;[0090]
• FIG. 23 is a view illustrating the use of a retractor to position the end of a scope;[0091]
• FIG. 24 is a view similar to FIG. 23 further illustrating the use of a retractor to position the end of a scope;[0092]
• FIG. 25 illustrates a cannula having a tethering cord connecting a balloon portion to the cannula wall;[0093]
• FIG. 26 is a sectional view illustrating a continuous mass of body tissue which is free of an opening;[0094]
• FIG. 27 is a schematic illustration depicting the manner in which the cannula of FIG. 25 is inserted into the mass of body tissue of FIG. 26 and expanded to form an open space in the mass of body tissue at a location adjacent to and axially outward from a distal end of the cannula;[0095]
• FIG. 28 is an enlarged view of the cannula of FIG. 27 and illustrating the manner in which a fiberoptic scope and a tool are inserted through—the cannula into the space formed in the body tissue at a location axially outward from the distal end of the cannula by expanding the cannula;[0096]
• FIG. 29 is an enlarged fragmentary sectional view of a cannula having a flexible wall and tethers, the flexible wall being shown in a retracted condition;[0097]
• FIG. 30 is a fragmentary sectional view, generally similar to FIG. 29, illustrating the flexible wall in an extended condition with a tether limiting outward movement of a portion of the flexible wall;[0098]
• FIG. 31 is a fragmentary sectional distal end view, taken generally along the line[0099]31-31 of FIG. 30, illustrating the manner in which a plurality of tethers extend outwardly from a main section of the cannula toward the flexible wall;
• FIG. 32 is a fragmentary schematic plan view of a portion of a side wall of the flexible wall of the cannula of FIGS. 29-31 and schematically illustrating the relationship between reinforcing fibers in a proximal portion of the side wall;[0100]
• FIG. 33 is a fragmentary plan view of another portion of the side wall of the flexible wall of the cannula of FIGS. 29-31 and schematically illustrating the relationship between reinforcing fibers in a distal portion of the flexible wall;[0101]
• FIG. 34 is a plan view of a portion of an end wall of the flexible wall of FIGS. 29-31 and schematically illustrating the relationship between reinforcing fibers in the end wall;[0102]
• FIG. 35 illustrates a cannula which is selectively expandable at one or more selected longitudinal locations;[0103]
• FIGS. 36 and 37 illustrate a cannula having a plurality of circumferentially spaced expandable segments;[0104]
• FIGS. 38-43 illustrate longitudinally extending radially expansible cannula segments;[0105]
• FIGS. 44 and 45 illustrate expandable devices having textured surfaces;[0106]
• FIGS. 46-49 illustrate a cannula having an expandable bladder portion with a varying wall thickness;[0107]
• FIGS. 50-52 illustrate flexible bladder portions having relatively rigid members molded therein;[0108]
• FIGS. 53 and 54 illustrate rigid members molded into the elastomeric material of an inflatable bladder circumscribing a cannula or other medical device;[0109]
• FIGS. 55 and 56 illustrate a cannula having a bladder with a doubled-over bladder portion;[0110]
• FIG. 57 is a schematic illustration of a cannula having the same general construction as the cannula of FIGS. 55 and 56, the cannula of FIG. 57 having tethers and being shown in a retracted condition;[0111]
• FIG. 58 is a schematic illustration of the cannula of FIG. 57 in an extended condition with the tethers restraining movement of a flexible wall portion of the cannula;[0112]
• FIG. 59 is a schematic illustration of a cannula having the same general construction as the cannula of FIG. 58, the cannula of FIG. 59 having a plurality of tethers disposed within a chamber formed by the expanded flexible wall of the cannula;[0113]
• FIG. 60 is an end view, taken generally along the line[0114]60-60 of FIG. 59, illustrating the manner in which a plurality of tethers are connected with the flexible wall of the cannula;
• FIG. 61 is a sectional view, taken generally along the line[0115]61-61 of FIG. 59, illustrating the manner in which a plurality of tethers extend outwardly from a main section of the cannula. toward an inner side surface of the flexible wall of the cannula;
• FIG. 62 is a sectional view, taken generally along the line[0116]6-2-62 of FIG. 59, illustrating the manner in which a plurality of tethers extend outwardly from a main section of the cannula towards the inner side surface of the flexible wall;
• FIG. 63 illustrates an expanded bladder having adjoining portions with different material characteristics;[0117]
• FIG. 64 illustrates an expanding device having an expanding bladder made of a plurality of materials laminated together;[0118]
• FIGS. 65A-65C illustrate triangular-shaped expanding portions;[0119]
• FIGS. 66A-66C illustrate trapezoidal-shaped expanding portions;[0120]
• FIGS. 67A-67C illustrate the use of overlapping and/or incomplete fibers for expansion control;[0121]
• FIGS. 68-76 illustrate a variety of bladder devices including reinforcing fibers and/or tethering cords; and[0122]
• FIGS. 77-79 illustrate a structural unit comprising a series of expandable bladders laminated together.[0123]
DESCRIPTION OF PREFERRED EMBODIMENTS
• FIGS. 1-3 illustrate an[0124]arthritis irrigation apparatus10. Theirrigation system10 includes acannula12 having adisc portion14 and a longitudinally extendingcannula body16. Acentral wall18 divides thecannula body16 into two longitudinally extendinglumens20 and22.
• An[0125]expandable bladder30 is connected to or formed integrally with thecannula12 at thedistal end32 andproximal end34 of thecannula body16. Theexpandable bladder30 includes a longitudinally extendingwall portion36 and a transversely extendingwall portion38. Theexpandable bladder30 is supplied with fluid under pressure through afluid supply port40 closed by arubber diaphragm seal42. Thelumens20 and22 are closed by similar diaphragm seals44 and46, respectively. Thecannula body16 has a recessedportion48 in which thebladder36 fits when unexpanded.
• The[0126]system10 is inserted into a pre-made opening until thedisc portion14 engages the skin. Upon the introduction of fluid under pressure into theexpandable bladder30, thebladder30 expands from the unexpanded condition illustrated in FIG. 1 to the expanded condition illustrated in FIG. 2. Thebladder wall36 moves radially outwardly, and skin or other tissue is trapped between thebladder wall38 and thedistal surface49 of thedisc portion14 of thecannula12.
• The[0127]system10 is thus locked in place, with thedistal end32 in position in a joint. Appropriate instruments may then be inserted through the diaphragm seals44 and46 into thelumens20 and22, respectively. For example, flushing fluid may be supplied to the joint through thelumen20, while it is removed from the joint by suction through thelumen22. When the joint is not being flushed, the diaphragm seals42,44 and46 seal the openings in thesystem10, and the expandedbladder30 retains thesystem10 in place in the body.
• It should be understood that any number of lumens, other than two, can be included in the[0128]cannula body16. The number of lumens is limited only by the size of the instruments to be inserted through thecannula body16. In a preferred embodiment, thedisc portion14 of thecannula body12 is about the size of a nickel, with thecannula body16 being correspondingly smaller. Of course, the dimensions and arrangement of the various portions of thesystem10 could be modified to enable the placement of other instruments through thecannula body16.
• Each of the lumens may have a controllable inflow-outflow portal. These can be substituted for the diaphragm seals. These portals may be a simple tube with an on-off valve attached, as is known in the art, or can be another suitable structure.[0129]
• FIG. 4 illustrates an alternate embodiment of the[0130]system10 in which asystem50 includes a round or doughnut-shapedbladder52 extending between thedistal end32 and theproximal end34 of thecannula wall16. This doughnut-shaped bladder can be easier or less expensive to manufacture, and also can provide more cushioning effect to the tissues which it engages. Again, tissue is trapped between thebladder52 and thedisc portion14 of thecannula12, to retain thesystem50 in place in the body.
• FIGS. 5 and 6 illustrate a variable size cannula in which inflatable bladders push apart two relatively rigid portions to move tissue. FIGS. 5 and 6 are transverse cross sections through a[0131]longitudinally extending cannula60, which can be any desired length. Thecannula60 expands radially outwardly along its length.
• The[0132]cannula60 includes a first C-shapedportion62 having ends64 and66 and a second C-shapedportion68 having ends70 and72. Aninflatable bladder74 has oneend portion76 fixed to theend portion64 of theportion62. Theopposite end portion78 of thebladder74 is fixed to theend portion70 of theportion68. Similarly, abladder80 has oneend portion82 fixed to theend portion66 of theportion62, and itssecond end portion84 fixed to theend portion72 of theportion68.
• The[0133]portion62 has an outwardly facingsurface86 and theportion68 has an outwardly facingsurface88. Thecannula60 has acentral opening90 which is enlarged in size upon expansion of thebladders74 and80 to provide a larger working space while reducing tissue damage. Upon the introduction of fluid under pressure into thebladders74 and80, theportions62 and68 are moved away from each other to engage tissue with theirsurfaces86 and88, respectively. The relativelyrigid portions62 and68 provide increased pushing strength of thecannula60 as compared to a soft inflatable bladder. Further, thecannula60 also holds its structural shape better and is able to maintain the opening better. Thus, with thecannula60, a limited incision can be made in the tissue, which incision is then enlarged by the cannula itself rather than with a cutting device. The application of suction to thebladders74 and80 causes them to deflate to return thecannula60 to its unexpanded condition. The tissue is viscoelastic and thus will stretch out during its expansion by theexpander60, and then return to its original unexpanded shape, i.e., the original size of the incision after removal of the cannula. Thus, less tissue damage results.
• Cannulas in accordance with the present invention may have one or more bladders as part of the cannula wall. These may create inward or outward expansion. For example, FIGS. 7A and 7B illustrate a longitudinal portion of a[0134]cannula92 having awall portion94 defining acentral opening96 through which surgical instruments or the like can be passed. Thewall portion94 includes aportion98 partially. defining afluid chamber100 which may be supplied with fluid under pressure through afluid supply line102 extending through thecannula wall94. On the introduction of fluid under pressure into thevolume140, thewall portion98 of thecannula92 expands radially outwardly, from the unexpanded condition of FIG. 7B to the expanded condition of FIG. 7A, as a seal or retainer against tissue.
• Similarly, the[0135]cannula104 illustrated in FIGS. 8A and 8B includes awall106 having aninner portion108 defining afluid volume110. Upon the introduction of fluid under pressure through asupply passage112 in thewall106, thewall portion108 expands radially inwardly to close at least partially thecentral opening113 in thecannula104. The expandingportion114 of thecannula104 thus acts as a valve or seal for thecentral opening110 of the cannula. This can be very useful if it is desired to close thecentral opening110 while leaving thecannula104 in place in the body tissue. Thecentral passage113 can also be closed completely. Alternatively, thewall portion108 can clamp onto an instrument or scope extending through thepassage113 to lock it in place.
• In addition to the cannula inner seals or valves formed by the radially inwardly expanding bladder walls, the present invention contemplates cannula inner seals formed by other structures. For example, a simple mechanical seal can be used such as a diaphragm seal like the[0136]seals44 and46 (FIGS. 1-3). Other forms of mechanical seals can be used, such as a membrane (iris) valve, screw lock, twist lock, or luer lock. It is intended that these alternatives be included within the scope of the invention.
• FIGS. 9A and 9B illustrate a[0137]cannula116 having an expandingportion118 in itswall120. Upon the introduction of fluid under pressure through afluid supply passage122 in thewall120, aportion124 of thecannula wall120 expands radially outwardly while a longitudinallyco-extensive portion126 of thewall120 expands radially inwardly to partially or completely close a centrallongitudinally extending passage128. Thus, thecannula116 has aportion118 which expands both inwardly and outwardly. The cannulas of FIGS. 7-9 thus illustrate the principle of expanding either inward or outward or both at selected axial locations along the longitudinal extent of a cannula.
• FIGS. 10A-10C illustrate the expansion of a stretchable cannula by an expandable member inserted therein. A[0138]cannula130 has awall132 defining a centrallongitudinally extending passage134. Thecannula130 is made of a stretchable material having viscoelastic properties whereby thewall130 when stretched outwardly will retain its stretched condition for a period of time. Anexpander136 includes astalk138 on the end of which is mounted an expandingportion140. Upon insertion of theexpander136 into thecannula130 as illustrated in FIG. 10B, the expandingportion140 may be expanded radially outwardly by the introduction of fluid under pressure through thestalk138, to stretch awall portion142 of thecannula wall132 radially outwardly. Upon subsequent deflation of the expandingportion140 of theexpander136, and removal of theexpander136 from thecannula130, thecannula wall portion142 remains in its stretched condition for at least a period of time. Thecannula130 is thereby retained in place in the surrounding tissues while instruments or a scope can be passed through it.
• The present invention contemplates monitoring the pressure applied to tissue by the expanding cannula. This can be done, for example, with any known pressure sensor or strain gauge. Such is indicated schematically at[0139]144 in FIG. 10C as being on the wall of thedevice136 used to stretch thecannula130. Alternatively, it is indicated schematically at146 in FIG. 10C as being on the wall of thecannula130.
• FIGS. 11-13 illustrate a[0140]cannula150 which comprises a cylinder expandable along its entire length. Thecannula150 has a central longitudinally extending workingpassage152 defined by aninner wall154. Aninflation space156 separates theinner wall154 from anouter wall158 of thecannula150. A series oftethering cords160 extend between theinner wall154 and theouter wall158.
• The inner and[0141]outer walls154 and158, respectively, of thecannula150 are constructed so that, upon the introduction of fluid under pressure into theinflation space156, both walls expand radially outwardly to a larger diameter. Fluid is introduced through a fluid inflow means (not shown) which may be a simple tube or valve in fluid communication with theinflation space156. Thecannula150 expands from the condition shown in FIG. 12 to a further expanded condition as illustrated in FIG. 13. Thetethering cords160 limit movement of theouter wall158 of thecannula150 from theinner wall154 of thecannula150. In a preferred embodiment, thetethering cords160 comprise fibers (either solid or stranded) having their ends fixed to theinner wall154 and theouter wall158 and extending therebetween. Thetethering cords160 may be unextensible, or they may be somewhat extensible upon the application of a relatively large amount of force. Use of thetethering cords160 is advantageous in that it allows for controlled expansion of spaced portions of an inflatable device.
• The[0142]cannula150 is circular in cross sectional shape. It should be understood that the present invention is not limited to circular cannulas, but specifically contemplates the provision of cannulas of any type described herein of other cross sectional-shapes. The cross sectional shape of a particular cannula may be selected in accordance with a particular application for that cannula. For example, an elliptical or oval-shaped cannula162 (FIG. 14) may be more suitable for insertion between adjacent tissue planes, as it conforms more to the opening between the tissue points. The oval-shapedcannula162 includes anouter wall164, aninflation space166, aninner wall168, and a working passage170- extending axially therethrough. Optionally a plurality oftethering cords172 extend between theinner wall168 and theouter wall164, and limit movement of theouter wall164 from theinner wall168.
• FIG. 15 illustrates, as exemplary of the other shapes of cannulas which may be provided, a rectangular (in this case square) shaped[0143]cannula174 optionally having a plurality oftethering cords176 extending between theouter cannula wall178 and aninner cannula wall180. Theinner wall180 defines a workingpassage182 extending longitudinally through thecannula174.
• FIG. 16 illustrates schematically a[0144]retractor510 in accordance with the present invention. Theretractor510 includes afluid supply structure512 and an expandable balloon orbladder514 having a flexible wall located at or near the end of thestructure512. The bladder is expandable, under the force of fluid under pressure, from an unexpanded or retracted condition as indicated in full lines at514 to an expanded or extended condition as shown in broken lines at516. In the expanded condition, thetransverse dimension518 of thebladder514 is significantly greater than its transverse dimension before expansion, that is, thedimension520. Also, in the expanded condition, thetransverse dimension518 of thebladder514 is significantly greater than itslongitudinal dimension520.
• When the bladder of the retractor is expanded inside the body, it retracts tissue. As seen in FIG. 17, a[0145]bladder522 is mounted on the end of aseparate shaft524 within a cannula orscope526. The cannula orscope526 has been inserted into the body through anopening528 in the skin (either pre-existing or made in situ) which has atransverse dimension530. Thebladder522 when in its unexpanded condition as shown in broken line is smaller than thedimension530 of the body opening, but when expanded, it expands to adimension532 which is significantly greater than thedimension530. An actual space or workingspace534 is formed which was not present before the expansion of the bladder.
• The newly-formed working space may be used, for example, for better use of a fiber optic scope as illustrated in FIG. 3. In FIG. 18, a[0146]retractor510 is passed through anopening536 in acannula538. A fiber optic scope shown schematically at540 is also passed through thecannula538. Thecannula538 is inserted into the body through an opening in thebody tissues542 which is only as large as the outer diameter of thecannula538. Theretractor510 is then inflated, with air or another fluid being supplied through a rigid orflexible shaft544 to anexpandable bladder546. Thebladder546 expands transversely, retracting thetissues542 transversely and creating a workingspace534. By axial manipulation of theshaft544, thebladder546 is movable either toward the end of thescope540 in the direction as indicated by thearrow548, or away from the end of thescope540 as indicated by thearrow550, as desired. Such manipulation of the retractor can selectively move and place the adjoining body tissues where the surgeon wants them to enable better use of thescope540 by the surgeon.
• As shown in FIG. 19, the[0147]retractor510 may be inserted into acannula552 through aseparate opening554 therein. Theopening554 is shown on the side of thecannula552, although, of course, it may be on the end of the cannula as is typical. Alternatively, theretractor510 may be inserted into the body through an opening in the body tissues separate from the opening through which the fiber optic scope is inserted. Either of these options allows for greater flexibility in the insertion and positioning of theretractor510 relative to the other instruments being used such as the arthroscope.
• Also as indicated in FIG. 19, the[0148]bladder558 may be eccentric or eccentrically located relative to theopening560 at the junction between thebladder558 and theshaft562. This is accomplished by using known techniques to form thebladder558 of a material, construction, and shape such that it expands into the eccentric shape as illustrated in FIG. 19 when inflated by fluid under pressure through theshaft562. In this manner, an improved visualization and workingspace534 is created which is eccentrically located relative to the other instruments being used. This may be preferable when the surgeon is using an angled scope.
• FIG. 19 is illustrative of the fact that the bladder of the retractor of the present invention may be formed so as to expand into any particular shape as desired for the particular application. This feature is also shown schematically in FIGS. 20A through 20E which illustrate, respectively, retractor bladders which assume in their expanded states in round, oval, eccentric, oblong, and conical shapes. Such shapes may generally be called “nonuniform” shapes for purposes of the present invention, and refractors with such a shape will expand in a “non-uniform” manner. Such shapes may include, for example, wedge- or U-shaped filaments which collapse at the skin, then expand at deep tissue planes for visualization and working space. The bladder may also cup and protect vital tissues such as nerves and arteries while working on other tissues such as muscle.[0149]
• Another typical form of construction is illustrated in FIG. 21, which shows a[0150]bladder564 which in its expanded condition assumes a toroidal shape. Again, thewidth566 of thebladder564 is significantly greater than its length568. The bladder568 is expanded by fluid under pressure received through afluid channel570 formed between a cannula or scopeouter wall572 andinner wall573. By virtue of the toroidal shape of the bladder568, theleading end574 of thescope576 may be passed axially completely through the retractor into the workingspace534 which has been created in thetissues578. Such abladder564 may also be mounted on a separate shaft inserted through the scope of the cannula.
• In all cases, the fluid pressure within the bladder of the retractor is monitored and controlled to keep the force exerted by the retractor at a safe level for tissue to prevent tissue necrosis. As indicated schematically in FIG. 22, a[0151]retractor510 is supplied with fluid under pressure from afluid pressure source580 via afluid supply line582. Aregulator584 controls the supply of fluid to theretractor510. Apressure sensor586 is located within theretractor510 and senses the pressure of the fluid within theretractor510. Thepressure sensor586 sends a signal which is representative of the fluid pressure within theretractor510, viawiring588, to amonitor590. Themonitor590 is connected viacontrol wiring592 to thepressure regulator584. The pressure of the fluid within theretractor510 may thus be monitored and controlled either manually or automatically, by means which are well known in the art and so need not be described further herein. Thesource580 of fluid supply may be, for example, the air pressure supply which is commonly found in hospital operating rooms.
• By virtue of this ability to monitor the pressure within the[0152]retractor510, theretractor510 can also be a useful diagnostic tool. The strength or pressure or resistance of tissue to movement can be measured by the pressure required to move it.
• FIGS. 23 and 24 illustrate the use of a retractor of the present invention to stabilize a fiber optic scope. The retractor[0153]510 (FIG. 23) includes abladder594 which retracts thebody tissues596 away from thescope598.
• Since the[0154]bladder594 engages and pushes radially outwardly onbody tissues596 all around thescope598, the retractor becomes fixed in position when it is so expanded. If thebladder594 is fixed to the end of thescope598, theretractor510 thereby fixes the end of thescope598 in position relative to thebody tissues596. When a camera is being used with thescope598, the picture normally moves or jumps around because of the movability of the end of thescope598. This is prevented by so using theretractor510 to stabilize thescope598, leaving the surgeon with both hands free to work and a steady view of the work area.
• FIGS. 23 and 24 also—illustrate how the retractor of the present invention can be used to control the placement of the tip of a fiber optic scope. The[0155]retractor510 is formed with aneccentric bladder594 which retracts thebody tissues596 away from thescope598 to a greater distance in one direction than in another. Thus, by rotating theretractor510, the surgeon can place the tip of thescope596 closer to the body tissue599 (FIG. 23) on one side of the workingspace534, or to the body tissue597 (FIG. 24) on the other side of the workingspace534. Such variable placement can, of course, also be attained via use of aretractor510 which includes a bladder which can be expanded to varying shapes.
• The retractor of the present invention has many uses in the surgical field. The[0156]retractor510 can be used to retract soft tissue from bone, for example within a joint. Theretractor510 is inserted between the bone and thesoft tissue112. Thebladder594 is then expanded. The soft tissue is forced away from the bone. The surgeon may then use a fiber optic scope or other instrument to work within the working space created by theretractor510. The retractor of the present invention can provide the force needed to move the soft tissue away from the bone may vary between about 100 and 1000 mm Hg, and thus, it is important to maintain the proper pressure between the two. Theretractor510 can do this since it operates on high fluid pressures of about 10 to 1000 mm Hg and it utilizes a high strength material such as Kevlar, Mylar, or another durable polymer such as Polylite®, a product of Reichhold Chemicals, Inc. This simple retraction of soft tissue from bone would otherwise be impossible.
• FIG. 25 illustrates the use of a tethering cord to position a bladder portion relative to a cannula wall. A[0157]cannula190 has a main section with anouter wall192 and aninner wall194 spaced therefrom. Thewall194 divides the interior of thecannula190 into a workingpassage196 and aninflation fluid passage198. Thepassage198 opens into a bladder orflexible wall200 fixed at thedistal end202 of thecannula190. Tetheringcords204 extend between thecannula wall192 and a junction orcrown206 of the bladder orflexible wall200. Thetethering cords204 limit movement of thecrown portion206 of the bladder orflexible wall200 from thecannula wall192.
• The[0158]cannula190 of FIG. 25 is only illustrative of the many ways in which bladder portions can be positioned relative to cannula portions by tethering cords such as thetethering cord204. The number and positioning and length of the tethering cords determines the relative movement of the various bladder portions to which they are attached, thus aiding in controlling the expanded shape of the bladder relative to the cannula.
• The[0159]cannula190 can be used to create an open space in a continuous mass of body tissue. Thus, a continuous mass207 (FIG. 26) of body tissue is free of naturally occurring openings. Themass207 of body tissue is enclosed byskin208. Theskin208, like themass207 of body tissue, is free of naturally occurring openings.
• A small slit or incision[0160]209 (FIG. 27) is formed by a surgeon in theskin208. Thecannula190 is then inserted through theslit209 in theskin208. At this time, thebladder200 in a retracted condition in which it is tightly disposed against the outer wall ormain section192 of the cannula.
• Once the[0161]cannula190 has been inserted through theslit209 and moved into themass207 of body tissue, the bladder orflexible wall200 is moved from the retracted condition to an extended condition. This is accomplished by a conducting fluid pressure through thepassage198 into theflexible wall200. The fluid pressure expands theflexible wall200 from a contracted condition to an extended condition.
• As the[0162]flexible wall200 is extended, aportion211 of themass207 of body tissue is moved outward away from theouter wall192 of the main section of thecannula190. Thus, as theflexible wall200 is inflated, an outer side surface of the flexible wall presses against theportion211 of themass207 of body tissue, in the manner indicated schematically by arrows in FIG. 27. This pressure moves at least part of theportion211 of themass207 of body tissue toward the left (as viewed in FIG. 27). As this occurs, force is transmitted from theportion211 of the mass of body tissue to a portion213 (FIG. 27) of themass207 of body tissue.
• The force transmitted through the[0163]mass207 of body tissue to theportion213 of the body tissue moves theportion213 of the body tissue away from the distal or axiallyouter end202 of thecannula190. As this occurs, anopen space215 is formed at a location in themass207 of body tissue where there was no space prior to insertion of thecannula190 and expansion of theflexible wall200.
• The[0164]portion213 of themass207 of body tissue is moved away from thedistal end202 of thecannula190 under the influence of force which is transmitted through the mass of body tissue from theportion211 of the body tissue to theportion213 of the mass of body tissue. Thus, the outer side surface of theflexible wall200 is effective to apply force, in the manner indicated by arrows in FIG. 27, against only theportion211 of themass207 of body tissue. Force is transmitted by body tissue from theportion211 of the mass of body tissue to theportion213 of themass207 of body tissue. The force transmitted through the body tissue moves theportion213 of themass207 of body tissue away from thedistal end202 of thecannula190 and thereby create theopen space215 in themass207 of body tissue.
• Creation of the[0165]open space215 in the mass of body tissue provides a viewing area adjacent to thedistal end202 of thecannula190 for a surgeon to operate. Thus, aendoscope217 and anoperating tool219 can be inserted through thepassage196 in thecannula190. The outer or distal ends of theendoscope217 andoperating tool219 project beyond thedistal end202 of thecannula190 into theopen space215. This enables a surgeon to view the distal end of theoperating tool219 through theendoscope217 and to view the portion of themass207 of body tissue which is to be operated on with thetool219. Of course, since the surgeon can view the operations being performed by thetool219, the work of the surgeon on thebody tissue207 is greatly facilitated.
• The flexible wall or[0166]bladder200 of the cannula190 (FIG. 28) includes aside wall191 and anend wall193 which are formed of an elastomeric material. When thecannula190 is inserted through theincision209, the natural resilience of theelastic end wall193 andelastic side wall191 causes the bladder orflexible wall200 to tightly enclose theouter wall192 of thecannula190. This results in thetethers204 being enclosed by the bladder orflexible wall200 and being pressed against theouter wall192 of thecannula190.
• After the[0167]cannula190 has been inserted through theincision209 and moved into thecontinuous mass207 of body tissue, thebladder200 is inflated to cause theelastic side wall191 andend wall193 of thebladder200 to move outward to the extended condition shown in FIG.28. A radially and axiallyinner end195 of theside wall191 of thebladder200 is bonded to the outer side surface of theouter wall192 of thecannula190. A radially inner end of theend wall193 is bonded at197 to the outer side surface of theouter wall192 of thecannula190. An opening for thefluid passage198 extends through theouter wall192 at a location between theconnection195 of theside wall191 with theouter wall192 of thecannula190 and theconnection197 of theend wall193 with theouter wall192 of the cannula.
• When the bladder or flexible wall[0168]200 (FIG. 28) is to be inflated from the retracted condition to the extended condition shown in FIG. 28, fluid pressure is conducted through thepassage198 into thebladder200. As the fluid pressure flows into thebladder200, anannular chamber199 is established around theouter wall192 of thecannula190. As this occurs, theside wall191 of thebladder200 presses body tissue radially outward and axially away from thedistal end202 of thecannula190 in the manner indicated by the arrows in FIG. 27. As this is occurring, the body tissue extends axially outward from thejunction206 between theside wall191 andend wall193 of the bladder orflexible wall200. The body tissue which extends outward from the junction orcrown206 of thebladder200 is tensioned and tends to continue outward from the junction. Due to the fact that theend wall193 extends radially outward from the cylindricalouter wall192 of thecannula190, an opening is formed immediately axially outward from theend wall193 as thebladder200 is inflated.
• As the[0169]bladder200 is inflated, thetether cords204 are extended from a nonlinear configuration toward the linear configuration illustrated in FIG. 28. When the bladder orflexible wall200 reaches the fully inflated condition shown in FIG. 28, an inflated structure is formed. Thetether cords204 restrain the junction between theside wall191 and193 from moving further radially outward. This results in theelastic side wall191 having a configuration corresponding to the configuration of a portion of a cone and theelastic end wall193 having a configuration corresponding to the configuration of a flat annular disk. Theside wall191 andend wall193 are initially formed to this configuration while they are in a stretched condition over a forming tool. Thetethering cords204 cooperate with theside wall191 andend wall193 to ensure that the inflated structure formed by thebladder200 has the configuration illustrated in FIG. 28.
• The[0170]body tissue207 which is pressed radially outwardly and axially away from thedistal end202 of thecannula190 by movement of thebladder200 from the retracted condition to the expanded condition shown in FIG. 28. causes the body tissue to move away from theend wall193 as the bladder is inflated. This results in the formation of theopen space215 axially outwardly from theend wall193. Thus, theportion211 of the body tissue disposed to the left (as viewed in FIG. 28) of the inflated bladder orflexible wall200 pulls or tensions the portion of the body tissue which extends across the circular crown portion orjunction206. The forces transmitted through the body tissue itself tends to pull the body tissue away from theend wall193 to form theopen space215 in the manner illustrated in FIG. 28.
• A cannula[0171]600 (FIGS. 29 and 30) has the same general construction as thecannula190 of FIGS. 25-28. Thecannula600 includes a tubularmain section601 having a cylindricalouter wall602 which extends from a proximal end portion (not shown) of thecannula600 to adistal end portion604 of the cannula. A flexible wall orbladder606 is connected with thewall602 of themain section601.
• The[0172]flexible wall606 has aproximal end portion607 which is bonded to anannular shoulder608 formed in thewall602. Acylindrical clamp ring609 also secures theproximal end portion607 to thewall602 of themain section601 of thecannula600.
• A[0173]distal end portion610 of theflexible wall606 is connected to the distal end of themain section601 of the,cannula600. In the illustrated embodiment of the invention, thedistal end portion610 of the flexible wall is bonded to the distal end of themain section601 of thecannula600. However, thedistal end portion610 of theflexible wall606 could be connected to the distal end of the-main section601 in other ways such as by the use of a mechanical retainer. When theflexible wall606 is in the initial or retracted condition shown in FIG. 29, the flexible wall tightly adheres to themain section601 of thecannula600 to provide a smooth outer surface which has a minimum of interference with body tissue as thecannula600 is inserted into a continuous mass of body tissue.
• An[0174]inner wall612 cooperates with thewall602 to form apassage614 for fluid. Thepassage614 has a proximal end (not shown) at which fluid under pressure is conducted into the passage. Thepassage614 has a plurality of circulardistal openings616 through which fluid can flow from thepassage614 to a space enclosed by theflexible wall606.
• When the[0175]flexible wall606 is to be inflated, fluid pressure flows through thepassage614 andopening616 and is applied against an inner side surface617 (FIG. 29) of the flexible wall. The fluid pressure applied against theinner side surface617 of theflexible wall606 causes the flexible wall to move from the retracted condition shown in FIG. 29 toward the fully extended condition shown in FIG. 30. As this occurs, a plurality oftether cords618 are pulled from a nonlinear or coiled configuration toward the linear configuration shown in FIGS. 30 and 31.
• When the[0176]flexible wall606 is in the retracted condition shown in FIG. 29, the flexible wall covers thetethers618 and presses them firmly against thetubular wall602 of themain section601 of thecannula600. Since thetethers618 are enclosed by theflexible wall606, they do not interfere with insertion of thecannula600 into a continuous mass ofbody tissue207 where an opening does not naturally occur. The relatively high pressure fluid conducted from thepassage614 through theopenings616 move theflexible wall606 outwardly away from themain section601 of thecannula600 to initiate the formation of aninflation fluid chamber620. As this occurs, theflexible wall606 forms aninflated structure622.
• The inflated[0177]structure622 has aside wall624 and anend wall626. Theside wall624 andend wall626 are connected at acircular junction628. Theside wall624 has a configuration corresponding to the configuration of a portion of a cone while theend wall626 has a configuration corresponding to the configuration of a flat annular disk when theflexible wall606 is in the fully extended position of FIG. 30. Thetethering cords618 limit outward movement of thejunction628 between theside wall624 and theend wall626 to impart the desired configuration to theinflated structure622.
• Each of the[0178]tethering cords618 has an outer end portion which is secured to theinner side surface617 of theflexible wall606 at thejunction628. In the illustrated embodiment of the invention, thetethering cords618 are bonded to the elastomeric material forming theflexible wall606. However, it is contemplated that thetethering cords618 could be connected with theflexible wall606 in many different ways. The inner end portions of thetethers618 are bonded to themain section601 of thecannula600. The inner end portions of thetethers618 could be secured to themain section601 of thecannula600 in many different ways other than bonding.
• The[0179]tethering cords618 limit radially outward movement of thejunction628 between theend wall626 andside wall624. By limiting outward radial movement of theend wall626 and theside wall624, thetethering cords618 restrain the elastic material of theflexible wall606. This results in theinflated structure622 having a configuration which corresponds to the configuration of a portion of a cone.
• Once the[0180]flexible wall606 has been moved to the extended condition of FIG. 30, instruments, such as an endoscope and/or operating tools, can be inserted through a cylindrical central opening630 (FIG. 31) formed in the main section601 (FIGS. 29 and 30) of thecannula600. In addition to thetethers618, reinforcing fibers632 (FIGS. 32, 33 and34) are utilized to impart the desired configuration to theinflated structure622.
• A portion of the reinforcing[0181]fibers632 is disposed in the side wall624 (FIGS. 32 and 33) of theinflated structure622. Another portion of the reinforcingfibers632 is disposed in theend wall626 of theinflated structure622. The reinforcingfibers632 cooperate with the elastomeric material, which may be silicone, or latex, to restrain the elastomeric material of theflexible wall606 against excessive stretching under the influence of fluid pressure applied against the inner side surface617 (FIGS. 30 and 31) of theflexible wall606.
• In the illustrated embodiment of the invention, the[0182]inflated structure622 has a configuration corresponding to the configuration of a portion of a cone. Therefore, aproximal portion607 of theside wall604 has a smaller diameter than adistal end portion633 of theside wall624. The density of reinforcingfibers632 in the proximal end portion607 (FIG. 32) of theside wall624 is greater than the density of reinforcingfibers632 in thedistal portion633 of theside wall624. By having the reinforcing fibers in the proximal end portion607 (FIG. 32) of theside wall624 closer together, the reinforcing fibers are effective to limit outward radial expansion of theproximal portion607 of theside wall624. The relatively widely spaced reinforcing fibers632 (FIG. 23) in thedistal end portion633 of theside wall624 allow thedistal end portion633 of theside wall624 to expand radially outwardly to a greater extent than theproximal end portion607 of theside wall624.
• The reinforcing[0183]fibers632 in theproximal end portion607 of the side wall624 (FIG. 32) includefibers634 having longitudinal axes which extend generally parallel to a longitudinal central axis of themain section601 of thecannula600. In addition, reinforcingfibers635 extend circumferentially around thedistal portion607 of theside wall624. The reinforcingfibers635 have longitudinal axes which extend generally perpendicular to the longitudinal axis of the reinforcingfibers634. The longitudinal extendingfibers634 and thecircumferentially extending fibers635 reinforce theproximal portion607 of theside wall624 to limit the extent to which the fluid pressure applied against theinner side surface617 of the side wall is effective to stretch the elastomeric material of theflexible wall606.
• Similarly, the distal end portion[0184]633 (FIG. 33) of theside wall624 has longitudinally extendingfibers636 having longitudinal axes which extend parallel to the longitudinal central axis of themain section601 of thecannula600. The reinforcingfibers632 in thedistal end portion633 of theside wall624 also include circumferentially extendingfibers637 which are perpendicular to thelongitudinally extending fibers636. The reinforcingfibers632 in the distal portion of theside wall624 are far more widely spaced than the reinforcing fibers in theproximal end portion607 of theside wall624. This enables the elastomeric material of thedistal end portion633 to stretch under the influence of fluid pressure applied against the inner side surface617 (FIG. 30) of theside wall624. Therefore, thedistal portion633 of theside wall624 stretches to have a substantially greater diameter than theproximal portion607 of theside wall624.
• The reinforcing[0185]fibers632 in the end wall626 (FIG. 34) includefibers638 which extend radially outwardly from thecylindrical passage630 through themain section601 of the cannula.Circumferentially extending fibers639 cooperate with theradially extending fibers638 to limit the expansion of theend wall626 under the influence of fluid pressure applied against theinner side surface617 of theflexible wall606. During formation of theflexible wall606, the elastomeric material of the flexible wall is configured to have a configuration corresponding to the desired, generally conical, configuration of the inflated structure622 (FIG. 30).
• The[0186]cannula600 is inserted into a continuous mass of body tissue, corresponding to the continuous mass207 (FIG. 26) of body tissue, with theflexible wall606 of thecannula600 in the retracted condition illustrated in FIG. 29. This enables thecannula600 to be inserted through a relatively small incision formed in the skin enclosing the continuous mass of tissue. Prior to insertion of thecannula600 into the continuous mass of tissue, the continuous mass of tissue is free of any openings. As thecannula600 is inserted into the continuous mass of body tissue with theflexible wall606 in the retracted condition of FIG. 29, the relatively smooth outer side surface of the cannula is effective to press aside the body tissue with a minimum of damage to the tissue.
• Once the[0187]cannula600 has been inserted into the continuous mass of body tissue, fluid under pressure is conducted through the passage614 (FIG. 29) to initiate inflation of theflexible wall606. As this occurs, theflexible wall606 begins to move away from themain section601 of thecannula600. This results in anouter side surface640 of theflexible wall606 pressing against the body tissue to move the body tissue away from themain section601 of thecannula600.
• As the inflation of the[0188]flexible wall606 continues, theouter side surface640 of the flexible wall disposed on theconical side wall624 presses the tissue both radially outwardly and axially away from the distal end of themain section601 of thecannula600. As this occurs, force is transmitted through the body tissue itself to pull the body tissue away from theend wall626 and the distal or axially outer end of thecannula600 to initiate the formation of an open space immediately axially outwardly of theend wall626.
• As the[0189]flexible wall606 continues to move away from the retracted condition of FIG. 29 toward the fully extended condition of FIG. 30, thetethers618 are straightened. When theflexible wall606 reaches the fully extended condition of FIG. 30, thetethers618 limit outward movement of thejunction628 between theend wall626 andside wall624. Thus, force is transmitted through thetethers618 from thejunction628 to themain section601 of thecannula600 to limit outward movement of thejunction628. The reinforcingfibers632 FIGS. 32, 33 and34), cooperate with thetethers618 to give theside wall624 the conical configuration shown in FIG. 30 and the end wall626 a flat annular disk-shaped configuration.
• FIG. 35 illustrates a[0190]cannula210 which is selectively expandable at one or more selected longitudinal locations. Thecannula210 includes a series of expandable wall segments defining a longitudinally extending central workingpassage212. The expandable segments illustrated include asegment214, asegment216, asegment218, and asegment220. As an example, thesegment218 is expandable, upon the introduction of fluid under pressure, to an expanded condition as illustrated at222 in FIG. 35. Thus, in accordance with the principles illustrated in FIG. 35, a cannula or other inflatable medical device can be expanded for positioning or sealing at one or more selected longitudinal locations.
• FIG. 36 similarly illustrates a[0191]cannula224 having a plurality ofexpandable segments226 through234 spaced circumferentially around thedistal end portion236 of thecannula224. Each of the segments226-234 is selectively expandable, as illustrated—in FIG. 37 showing thesegment234 expanded radially outwardly. Accordingly, it is seen that the present invention also contemplates a cannula or bladder, or other inflatable medical device, having a plurality of circumferentially disposed segments expandable radially outwardly upon the selective control of the user of the device. Such selective expansion is useful in selectively positioning the cannula within the tissue in which it is located, in avoiding damage to certain tissue such as nerve tissue, or in protecting or moving certain tissue selectively.
• FIGS. 38-43 illustrate such longitudinally extending radially expansible segments of a cannula or bladder or other inflatable medical device in accordance with the present invention. Each segment shown is one of a series of similar segments (not shown) spaced circumferentially around or formed as part of the wall of a cannula or[0192]other device250. Theexpansible segment240 illustrated in FIGS. 38-43 is formed as a bellows or accordion and is expandable to a larger extent at itsdistal end244 than at itsproximal end242. If thedistal end244 of theexpansible segment240 is located adjacent a distal end of a cannula, the cannula will thus be expandable directly at its tip. The bellows-like construction of thesegment240 provides significant structural rigidity and can transmit in a controlled manner a significant amount of force between its radiallyouter surface246 and its radiallyinner surface248 adjacent—the wall of thecannula250. Thesegment240 is inflated by introduction of fluid under pressure in a known manner into the inflation space252 (FIG. 41).
• The[0193]expandable segment254 illustrated in FIGS. 42 and 43 has a smoothouter skin256 supported by a plurality of expandable bellows-shapedhoops258 spaced longitudinally along the length of thesegment254. Theskin256 presents a smooth surface to adjoining tissues upon expansion of thesegment254. Thehoops258 provide structural rigidity to thesegment254, and control the shape of expansion of theskin256. It should be understood that other configurations of thehoops258, which support theskin256 of thesegment254, are contemplated.
• FIGS. 44 and 45 illustrate expandable devices having textured surfaces for grip and location control. The[0194]retractor260 illustrated in FIG. 44 includes astalk portion262 and abladder portion264 attached thereto. Thebladder portion264 has apebbled surface266. The retractor268 (FIG. 45) has astalk portion270 and abladder portion272. Thebladder272 has a ribbedsurface274. Other types of texturing or finishing may be provided for an expandable device in accordance with the present invention. Any suitable surface configuration may be used to increase the grip provided between the outer surface of the expandable device and the tissue which it contacts. It should be noted that the surface texturing may also increase the structural rigidity of the expanded device.
• FIGS. 46-49 illustrate an expanding[0195]device280 which is preshaped and has a varying wall thickness in its expanding bladder portion. The expandingdevice280 includes asupport member282 which may be a solid stalk or a hollow cannula or other member. Thesupport member282 has a widenedproximal portion286, a narrower diametercentral portion288, and a wideneddistal portion290.
• Bonded to the[0196]support member282 is an expandingbladder292. The expandingbladder292 includes aproximal portion294 bonded to theproximal portion286 of thesupport member282. The expandingbladder292 also includes adistal portion296 bonded to thedistal end portion290 of thesupport member282. Extending distally from theportion294 is a first expandingportion298 having a thinner wall section at itsproximal end300 and a thicker wall section at itsdistal end302. Extending. distally from the expandingportion298 to thethin wall portion296 is a second expandingportion304. The second expandingportion304 is thicker at its proximal end366, than at itsdistal end308, having a tapering cross section between the first expandingportion298 and thedistal end portion296.
• When in the unexpanded condition, the first and second expanding[0197]portions298 and304, respectively, of theexpandable bladder292 generally lie flat within the recess formed by thenarrow portion288 of thesupport member282. Upon the introduction of fluid under pressure into the interior of thebladder292 through a port (not shown) in thesupport member282, thebladder292 expands from the condition illustrated in FIG. 46 to the—condition illustrated in FIG. 47. The expandingportions298 and304 expand radially outwardly as illustrated. Because the material of thebladder292 is thinner at its axiallyouter end portions300 and308, that material stretches more and so thethicker portions302 and306 move radially outwardly the greatest amount. The proximal anddistal end portions294 and296, respectively, are prestretched, that is, stretched to a diameter greater than their relaxed condition, for insertion over thesupport member282.
• Thus, it is seen that the wall thickness of a bladder can be varied at selected locations to control the rates and distances of expansion of the bladder portions. Further, portions of the bladder can be prestretched so that they reach their maximum elongation at an earlier amount of expansion. These factors can be used to control the expanded shape of the bladder.[0198]
• In addition, there may be provided ribs such as the[0199]longitudinally extending ribs310 illustrated in FIGS. 48 and 49 which are of an increased wall thickness to provide structural support and expansion control of the elastomeric material of the bladder. Theribs310 are illustrative of any region of increased wall thickness used to control the shape of expansion. Such regions may run longitudinally as illustrated in thedevice280, or may run transversely or circumferentially or in other directions. Taken in combination, all of these factors are usable to control the shape of expansion of an inflatable medical device.
• In accordance with a further embodiment of the invention, relatively rigid members such as plates may be molded into relatively flexible bladder portions to define edges and surfaces, as illustrated in FIGS. 50-52. A medical device[0200]312 (FIG. 50) includes asupport member314 such as a cannula to which is attached an expanding (elastomeric)bladder316. The attachment between thebladder316 and thesupport member314 is not shown in these particular cross-sectional views, but may be in any manner known or as described herein. Thebladder316 has an elastomericcurved portion318 and anelastomeric portion319. Aplate320 is molded into thebladder316 and has anedge322. Asecond plate324 molded into thebladder316 has anedge326. Upon the introduction of fluid under pressure into the volume between thesupport member314 and thebladder316, the bladder expands radially outwardly from the condition shown in FIG. 50 to the condition shown in FIG. 51. Although theelastomeric portion318 of thebladder316 changes dimensions, theplates320 and324 do not. Thus, the expandingdevice316 includes flat surfaces and edge surfaces which move radially outwardly and maintain their rigid condition upon expansion of thedevice312. Theplates320 and324 thus control and partially define the expanded shape of thedevice312.
• Alternatively or additionally, as illustrated in FIG. 52,[0201]tethering cords328 may be employed between thesupport member314 and theplates320 and324. Thetethering cords328 also serve to control and/or limit expansion of thedevice312. Additionally, it can be seen that the device of FIG. 52 includeselastomeric bladder portions330 extending directly between theplates320 and324 and thesupport member314. Again, this is an alternative form of the construction. Expanding bladders constructed in accordance with the present invention can use any one or more of these various means of controlling or limiting the expansion of the inflatable medical device, in order to achieve the optimum structure for the particular application.
• FIGS. 53 and 54 further illustrate the use of rigid plates or members molded into elastomeric material of an inflatable medical device. An expanding[0202]bladder332 is fixed circumferentially by means not shown around acannula334. Thecannula334 includes acannula wall336 defining a longitudinally extendingcentral opening338. The expandingbladder332 includes anelastomeric material340 within which are molded a series of relativelyrigid plates342. Between the expandingbladder332 and thecannula wall336 is afluid inflation space344. Upon the introduction of fluid under pressure into theinflation volume344, the expandingbladder332 expands radially outwardly from the condition shown in FIG. 53 to the condition shown in FIG. 54. Theelastomeric material340 stretches and elongates circumferentially. The areas of theelastomeric material340 which are devoid ofplates342 stretch further, thus allowing theplates342 to separate. Theplates342, which were previously in overlapping position, are separated as illustrated in FIG. 54. Theplates342 impart structural rigidity and strength to theelastomeric material340. The invention is not limited to the particular configuration of rigid plates and elastomeric material illustrated, but contemplates any such configuration of relatively rigid members or portions in a relatively stretchable matrix material.
• The expanding device illustrated in FIGS. 55 and 56 includes a doubled-over bladder portion to allow maximum expansion at the distal end portion of the device. The device includes a cannula or stalk or[0203]other support member350. An expandingbladder352 is bonded at354 to aproximal portion356 of thesupport member350, and at358 to adistal end portion360 of thesupport member350. The material of the expandingbladder352 is doubled-over at362 adjacent thedistal end portion360. Upon the introduction of fluid under pressure into the volume defined by thebladder352, through afluid supply port364, thebladder352 expands from the condition shown in FIG. 55 to the condition shown in FIG. 56. Because of the doubled-overportion362 of thebladder352, maximum expansion is gained at the distal end of the device rather than at the center or the proximal end of the expandingbladder352. Again, such a device may include bladder portions having varying wall thicknesses as discussed above, tethering cords, etc., all to control the expanded shape of the device.
• The expanding device illustrated in FIGS. 57 through 62 includes a doubled-over bladder portion to allow maximum expansion at the distal end portion of the device in the manner previously described in connection with FIGS. 55 and 56. The device includes a cannula having a main section or[0204]stalk850. An expanding bladder orflexible wall852 is bonded at854 to aproximal end portion856 of thesupport member850 and at858 to adistal end portion860 of the main section850 (FIGS. 57 and 58). The material of the expandingbladder852 is doubled-over at862 adjacent to thedistal end portion860.
• Upon introduction of fluid under pressure into the volume-defined by the[0205]bladder852, through a fluid supply port864 (FIG. 57), the bladder orflexible wall852 expands from the condition shown in FIG. 57 to the condition shown in FIG. 58. Because of the doubled-overportion862 of thebladder852, maximum expansion is gained at the distal end of the device rather than at the center or proximal end of the expandingbladder852. Again, such a device may include bladder portions having varying wall thicknesses as discussed above or reinforcing fibers to control the expanded shape of the device.
• In the embodiment illustrated in FIGS. 57 and 58,[0206]tethering cords870 extend from themain section850 of the cannula to ajunction872 between aside wall874 and an end wall876 (FIG. 58) of the flexible wall orbladder852. Thetethering cords870 limit the extent of outward movement of thejunction872 when the flexible wall orbladder852 is inflated from the retracted condition of FIG. 57 to the extended condition of FIG. 58. Theside wall874 of the inflated flexible wall has a configuration corresponding to the configuration of a portion of a cone. Theend wall876 has a configuration corresponding to the configuration of an annular disk. However, it should be understood that theend wall876 slopes radially and axially outwardly from a location where theside wall876 is connected with themain section850 of the cannula to thejunction872 between the end wall and theside wall874.
• In accordance with a feature of this embodiment of the invention,[0207]tethering cords870 extend outwardly from the distal. end portion of themain section850 to thejunction872 between theside wall874 andend wall876. Thetethering cords870 limit outward movement of the flexible wall orbladder852 to assist in imparting the desired configuration to the bladder when it is in the expanded condition of FIG. 58. Although only a pair oftethering cords870 are shown in FIGS. 57 and 58, it should be understood that there is a circularouter array880 of tethering cords which extend from themain section850 of the cannula outwardly to thejunction872. Although any desired number of tethering cords could be used, in the illustrated embodiment of the invention, there are nine tethering cords in thecircular array880 of tethering cords.
• In the embodiment of the invention illustrated in FIGS. 59-62, the cannula, has the same general construction as the cannula of FIGS. 57 and 58. However, in the embodiment of the invention illustrated in FIGS. 59-62, tethering cords are provided between an inner side surface of the[0208]side wall874 of the bladder or flexible wall and themain section850 of the cannula. Since the embodiment of the invention illustrated in FIGS. 59-62 is generally similar to the embodiment of the invention illustrated in FIGS. 57 and 58, similar numerals have been utilized to designate similar components.
• In accordance with a feature of the embodiment illustrated in FIGS. 59-62, an[0209]intermediate array882 oftethering cords870 extends between the main section8.50 of the cannula and the inner side surface of the flexible wall orbladder852. In addition, an axiallyinner array884 oftethering cords870 extends between the inner side surface of the bladder or flexible wall and themain section850 of the cannula.
• The three[0210]arrays880,882, and884 oftethering cords870 used to restrain outward-movement of the flexible wall orbladder852 in the embodiment of the invention illustrated in FIGS. 59-62 are effective to cause the extendedflexible wall852 to form an inflated structure having a generally conical configuration.
• FIG. 63 illustrates an expanding[0211]bladder370 having adjoining portions with different material characteristics. The device is shown in end view as disposed circumferentially around acannula372.Alternate portions374 of the device are made of a first material having a first set of material characteristics, while theinterfitted portions376 are made of a second material having a second set of material characteristics. For example, one material may have a lower modulus of elasticity and the other a higher modulus of elasticity. One may be thicker and the other thinner one may be elastomeric and the other not. Other combinations are possible. The portions may be bonded together with adhesive, may be heat-sealed together, or may be solvent sealed. One portion can be made of metal. PVC is also a suitable material.
• Upon the introduction of fluid under pressure into the expanding[0212]device370, theportions374 and376 expand or move at different rates or into different shapes. The adjoining of different materials can be used to control the expanded shape of thedevice370.
• FIG. 64 illustrates an expanding device[0213]380 having an expanding bladder382 made of a plurality of materials laminated together. The expanding portion382 is mounted on a stalk orcannula384. The bladder382 includes an outer layer386 of a first material laminated to aninner layer388 of a second material. Again, the layers may have differing material characteristics—perhaps polymers with specific properties bonded together. For example, the layer386 may be of a different durometer from the material of thelayer388. One of the layers may provide structural support while the other provides fluid sealing capabilities. One layer may provide puncture resistance while the other provides expansion shape control. These are some of the many properties available with such laminated structures.
• It should also be noted that the expandable bladder[0214]382 has an expanded dimension many times greater than its unexpanded dimension as illustrated in dashed lines in FIG. 64. This is illustrative of the large degree of expansion which the expandable bladders of the present invention are able to generate. For example, expandable bladders in accordance with the present invention have been built having expansion rates of approximately 700% as compared to the unexpanded diameter.
• FIG. 65A illustrates a triangular shaped expanding[0215]element400 fixed to a supporting device indicated at402. The expandingelement400 has relatively thinwalled portions404 and a relativelythick wall portion406. Upon the introduction of fluid under pressure into thevolume408 defined by thebladder400, the relatively thinwalled portions404 are stretched to a greater extent than the relatively thickwalled portion406. In the similar expanding segment410 (FIG. 65B), afiber412 is embedded in the elastomeric material of the expanding segment to control and limit its expansion. Again, in the similar expandingsegment414 illustrated in FIG. 65C, afiber mesh416 is embedded in the elastomeric material of the expanding segment to strengthen it and to control its expansion.
• The expanding segments illustrated in FIGS. 66A, 66B, and[0216]66C are similar to FIGS. 65A-65C in structural composition but are trapezoidal shaped rather than triangular shaped. FIG. 66A illustrates an expandingsegment418 connected with asupport member420. Thesegment418 includes relatively thinwalled portions422 and a relatively thickwalled portion424. Upon the introduction of fluid under pressure into the volume defined by the expandingportion418, the relatively thinwalled portions422 stretch to a greater extent than the relatively thickwalled portion424 whereby the relatively thickwalled portion424 moves radially outwardly to a greater extent. The expanding segment426 (FIG. 66B) includes an embedded reinforcingfiber428 for expansion control purposes. The expanding segment430 (FIG. 66C) includes an embeddedfiber mesh432 for structural support and expansion control purposes. The structural compositions and uses of embedded fibers and fiber meshes illustrated in FIGS. 65 and 66 are merely illustrative. of the various ways in which fibers embedded in the elastomeric material of an expanding medical device can be used to control the expansion thereof.
• FIGS. 67A-67C illustrate the use of overlapping and/or incomplete reinforcing fibers for expansion control. A stretchable elastomeric material[0217]434 (FIG. 67A) has a plurality of fibers or other reinforcingelements436 embedded therein. As thestretchable material434 is elongated, the elastomeric material in the stretch zones438 (FIG. 67C) between thefiber portions436 stretches to a greater extent than the material immediately around thefibers436. Further, the embedded fibers resist transverse expansion of the elastomeric material while encouraging longitudinal expansion as shown. These drawings are merely illustrative of the use of the concept of overlapping fibers with stretch zones to control expansion rates of an elastomeric material used in an expanding medical device such as a cannula or catheter. The present invention contemplates other such arrangements of fibers or reinforcing elements in the elastomeric materials.
• For example, FIGS. 68-70 illustrates a[0218]bladder retractor440 fixed to acannula442. A plurality of circumferentially extending reinforcingfibers444 are embedded in anelastomeric matrix material446. In addition, a plurality oftethering cords448 extend radially between thecannula442 and theelastomeric material446 to limit the radially outwardly expansion. As can be seen in FIG. 70, the reinforcingfibers444 are not complete but rather are broken fibers extending circumferentially within thematrix material446 to define stretch tones between them. Alternatively, the reinforcing fibers may be complete, as illustrated in FIGS. 71 and 72. In theretractor450 illustrated in FIGS. 71 and 72, a plurality of complete circumferentially extending reinforcingfibers452 are embedded in thematrix material454. Theretractor456 illustrated in FIGS. 73 and 74 includes a plurality of longitudinally extending incomplete reinforcingfibers458 embedded in the matrix material460. Theretractor462 illustrated in FIGS. 75 and 76 includes a plurality of longitudinally extending complete reinforcingfibers464 embedded in anelastomeric matrix material466. Again, the invention contemplates other such configurations of reinforcing fibers embedded in matrix materials, and is not limited to those shown.
• FIGS. 77-79 illustrate a series of expandable bladders laminated together to define a[0219]structural unit470. A series of upper longitudinallyextendable bladders472 have their ends fixed between anupper member474 and acentral member476. A series of lower longitudinally extendingbladders478 have their ends fixed between thecentral member476 and alower member480. A covering or retainer482 (FIG. 79) may enclose all of the units. Upon the introduction of fluid under pressure, thebladders472 and478 expand longitudinally from the condition illustrated in FIG. 77 to the condition illustrated in FIG. 78. when thebladders472 and478 are fully inflated as illustrated in FIG. 54, they define, together with themembers474,476 and480 and theretainer482, a rigid structural unit. This type of laminated bladder construction will find many suitable uses. It should be understood that other configurations of bladders laminated together are contemplated and are within the scope of the invention.
• From the above description of the invention, those skilled in the art will perceive improvements, changes and modifications in the invention. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims.[0220]

Claims (12)

1-11. (cancel)

12. A surgical device for providing a working passage through tissue, the surgical device comprising:

an elongate tubular member having proximal and distal openings defining a bore therethrough; and

at least two wall segments disposed on said tubular member, each wall segment having an uninflated state and an inflated state wherein the at least two wall segments are longitudinally spaced apart on said tubular member.

13. The surgical device ofclaim 12, wherein the bore is dimensioned to receive an endoscopic instrument.

14. The surgical device ofclaim 12, wherein each wall segment extends circumferentially about the tubular member.

15. The surgical device ofclaim 12, wherein a surface of each wall segment is substantially flush with an exterior surface of said tubular member when said wall segment is in the uninflated state.

16. The surgical device ofclaim 12, wherein each wall segment has an outside diameter greater than an outside diameter of the tubular member when said wall segment is in the inflated state.

17. The surgical device ofclaim 12, wherein when the at least two wall segments are in the inflated state, the at least two wall segments define a gap therebetween.

18. The surgical device ofclaim 17, wherein the at least one layer of tissue is captured by said gap.

19. A method of positioning a surgical access device through tissue of a patient, the method comprising the steps of:

inserting the surgical access device through tissue, said surgical access device comprising:

an elongate tubular member having proximal and distal openings defining a bore therethrough; and

first and second wall segments disposed on said tubular member, each wall segment having an uninflated state and an inflated state wherein the first and second wall segments are longitudinally spaced apart on said tubular member;

introducing a fluid under pressure to the first wall segment causing it to go from its uninflated state to its inflated state; and

positioning said surgical access device such that at least a portion of the first wall segments is in contact with tissue.

20. The method ofclaim 19, wherein said bore is dimensioned to accommodate an endoscopic instrument.

21. The method ofclaim 19, further comprising the step of:

introducing a fluid under pressure to the second wall segment causing it to go from its uninflated state to its inflated state and defining a gap between said first and second wall segments.

22. The method ofclaim 21, wherein at least one layer of tissue captured in said gap.

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