BACKGROUND OF THE INVENTION1. FIELD OF THE INVENTIONThe present invention relates to laparoscopically implantable gastric bands for encircling the stomach having ribs and chambers in the inflatable portion to reduce fatigue or crease fold failure in the device, while increasing the range of adjustment. A method for treating morbid obesity utilizing a fatigue-resistant gastric banding device is also disclosed.
2. DESCRIPTION OF THE RELATED ARTThe band comprises a belt that can be passed around the stomach and locked into an encircling position in order to create a stoma opening within the stomach. An adjustable portion of the band comprises an inflatable member, which permits fine adjustment of the stoma opening after the stoma is created by locking the band in place. The stoma opening may be adjusted by injecting or withdrawing a fluid into or from an inflatable member. The means for injecting the fluid into the inflatable member usually comprises a fill port located beneath the skin that can be accessed extracorporeally by transdermal injection. Thus, following implantation, the gastric band can be adjusted to enlarge or reduce the stoma as required.
The gastric band is implanted surgically, via open or laparoscopic surgery, which may involve placement of a calibrating apparatus in the stomach to position the stoma and size the pouch created above the stoma. The gastric band is imbricated in position about the stomach to prevent slippage, usually by gastro-gastric sutures (i. e. tissue is wrapped over the band and sutured to itself).
As disclosed by Vincent, the inflatable member or shell is preferably substantially coextensive with an inner stomach-facing surface of the gastric band.
Furthermore, it has been observed that the inflatable member should not wrinkle or fold when adjusted, so as to present a substantially smooth contour along the inner circumference. This ensures not only that stomach tissue will not be pinched by the inflatable member, which could lead to discomfort or necrosis, but also protects the shell from a phenomenon known as crease fold failure, which may occur if it is inflated beyond its intended range of adjustment. In the field, it has been observed that silicone or other elastomeric materials commonly used in the manufacture of gastric bands can fatigue or fail if repeatedly compressed, folded, wrinkled, buckled under stress or creased by, for example, over-inflation. This failure mode, which may include abrasion of the opposing surfaces against one another, abrasion of the inner surface of the fold "peak" against the opposing chamber wall, or fatigue of the material at folder intersections (the most highly-stressed areas), is sometimes referred to as crease fold failure.
In some cases, it has also been noted that existing adjustable gastric bands do not provide the overall size or range of adjustment desirable for use in particular patients. For instance, existing gastric bands may be either too large or too small to encircle a patient's stomach, while still allowing for a properly sized stoma. This may be due, for instance, to variations from patient to patient and their individual internal physiologies. Thus, gastric bands are now available in several different sizes, measured according to the circumference of the band (e.g. 9.75 cm, 11 cm, etc.). But due to variations in not only patient physiology, but also in the location and encircling position of the band, the surgical technique used, etc., it may not be evident what size band is necessary until a patient is undergoing surgery. Rather than have a variety of different sizes of gastric bands on hand during the surgical procedure, it would be desirable to have one universal size gastric band available that is adjustable over a wider range than those bands known in the prior art.
If the overall size of the gastric band is increased, the inflatable shell portion may not be capable of being adjusted to form a relatively small stoma without creases, wrinkles or folds forming on the inner stomach-facing surface, which may lead to fatigue or failure of the inflatable member, necessitating additional surgery. It would therefore be desirable to provide a universal size of a fatigue-resistant gastric band having an inflatable member that can be adjusted over a wide range of stoma openings.
US 5,152,770 discloses an occlusion device for application around a newly-shaped orifice of the stomach in obese patients. The device comprises bulbs which together form a substantially rectangular balloon. The device was found not to be adapted for laparoscopic placement (T 1240/05).
Finally,
WO 00/00108 A1 discloses a food intake restriction device which may be designed to form a row of bulges along the band so that the formation of creases on the inner side of the tubing as the band is bent into a loop is avoided. This is said to dramatically increase the lifetime of the band. Adjacent bulges are spaced from each other when the cavity of the band is filled with fluid. The band is surgically implanted.
The foregoing demonstrates a need for a laparoscopically implantable gastric band having a universal size and offering a range of adjustability suitable for use in a variety of patients with varying internal physiologies, which reduces pinching of the stomach upon initial placement.
The present invention provides a gastric band as recited in claim 1 below. Advantageous embodiments are recited in the dependent claims. The invention accordingly provides a gastric band having an inflatable member that is substantially coextensive with an inner stomach-facing surface of the gastric band.
The present invention also provides a gastric band having an inflatable member that does not wrinkle or fold when adjusted over a wide range, so as to present a substantially smooth contour along the inner circumference, and to avoid fatigue or failure of the member itself.
The invention provides a fatigue-resistant gastric banding device for the treatment of morbid obesity. The device has a gastric band suited for laparoscopic placement around the stomach of a patient to form an adjustable stoma opening. The gastric band has a multi-chambered inflatable member for adjusting the inner circumference of the band. The inflatable member is substantially coextensive with an inner stomach-facing surface of the gastric band. The inflatable member is chambered so as to not wrinkle or fold when adjusted over its range of adjustment, thereby presenting a substantially smooth contour along the inner circumference and reducing fatigue or failure of the device.
Separating the chambers is at least one reinforcing rib. Upon inflation of the gastric band, the chambers ribs, preferably in conjunction with notches, eliminate creasing, folding or wrinkling of said inflatable shell, thereby reducing fatigue on the device.
The fatigue-resistant gastric band of the present invention may be adjusted by adding fluid to or removing fluid from the chambered inflatable member or shell by means of a subcutaneous access port, via a remotely controllable pump, using pressurized fluid or through other means well known to one skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGSThe following detailed description given by way of example, but not intended to limit the invention solely to the specific embodiments described, may best be understood in conjunction with the accompanying drawings in which:
- Figure 1 is a top view of a gastric band according to one embodiment of the present invention;
- Figure 2 is a cross-sectional view of the gastric band shown in Figure 1 taken along line 2-2;
- Figure 3 is a top and side view of the encircling portion of a fatigue-resistant inflatable shell of the gastric band of Figure 1;
- Figure 4 is a cross-sectional top view of the fatigue-resistant inflatable shell of Figure 3 taken along line 4-4;
- Figure 5 is a close up cross-sectional view of a convolution point of the fatigue-resistant inflatable shell of Figure 4 taken in area 5.
- Figure 6 is a cross-sectional view of the fatigue-resistant inflatable shell of Figure 3 showing the relative thickness of a reinforcing rib;
- Fig. 7 is a perspective view of the encircling portion of a fatigue-resistant inflatable shell of a gastric band according to the present invention; and
- Figure 8 is a top and side view of a portion of the gastric band of Figure 1 straightened to show the width and projection of the chambers in relation to the inner band portion.
DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTSAn inflatable gastric band 10 according to the present invention is shown inFIG. 1. The gastric band 10 has a body portion 11 and an inflatable portion or shell 16. The body portion 11 has a head end 12 and a tail end 13. The head end 12 of the body portion 11 has a buckle 19 with a pull-tab 18. The tail end 13 includes a belt tab 17. Upon insertion of the tail end 13 including a fill tube 14 through the buckle 19, the tail end 13 is drawn through the buckle 19 until the belt tab 17 catches on the exit side 20. In this position the gastric band 10 is releasably locked in a closed loop position and secured by the buckle 19 and the belt tab 17.
The fill tube 14, which is generally a tube having a single lumen (not shown) coextensive therewith, is connected to an end of the gastric band 10. InFIG. 1 it is shown attached to the tail end 13 and in fluid communication with an inflatable shell 16. It will be apparent to one of skill in the art that other arrangements of the fill tube 14 could be made including attachment to the head end 12 without departing from the scope of the present invention.
The inflatable shell 16 is formed to receive the body portion 11 as shown inFIG. 2, which is a cross sectional view ofFIG. 1 taken along line 2-2. The inflatable shell 16 is preferably substantially coextensive with the body portion 11, as shown inFIG. 1. The body portion 11 may be attached to the interior of the inflatable shell 16 through the use of adhesives compatible for use within the body or other methods known to those skilled in the art of implantable medical device manufacture. The inflatable shell 16 includes an inner stomach-facing surface 15 that forms a stoma when placed around the stomach. It is this surface that has traditionally been the location of failure due to crease fold fatigue.
To reduce the potential for crease fold failure or high stresses in the inner surface 15, the inflatable shell 16 has pre-formed stress-reducing notches 8 separating chambers 6.FIG. 3 shows a top view of the inflatable shell 16 of gastric band 10 with plurality of chambers 6 each separated by a respective notch 8.FIG. 3 differs fromFIG. 1 in that it shows just the inflatable shell 16 without the inner portion 11 of the gastric band 10.
Similarly,FIG. 4 shows a cross-sectional top view of the inflatable shell 16 shown inFIG. 3. InFIG. 4, the inside of the inflatable shell 16 is depicted with reinforcing ribs 7 at each of the notches 8 separating each of the chambers 6.
However, as shown inFIG. 3 the first chamber 24 and last chamber 26 of the inflatable shell 16 may be formed with only one rib 7.
The band may be formed with a single notch 8 along the inner stomach-facing surface 15 of the inflatable shell 16, or more preferably, with multiple notches 8. Similarly, the band may be formed with a single reinforcing rib 7 inside the inflatable shell 16, or more preferably, with multiple ribs 7. Most preferably, the inflatable shell 16 is formed with corresponding ribs 7 and notches 8. The notches 8, chambers 6, and ribs 7 are formed in the inflatable shell 16 during the manufacturing process and are a feature of the inflatable shell 16 of the gastric band 10 whether filled or unfilled (i. e. whether the band is inflated or un-inflated). This helps to ensure that upon initial positioning of the gastric band 10 there is no pinching of the stomach.
FIG. 6 shows a cross sectional view of the inflatable shell 16 ofFIG. 3. InFIG. 6 the thickness of the rib 7 can be seen relative to the thickness of the inflatable shell 16.FIG. 6 also shows that the width of the chambers 6 may extend beyond the width of an outer surface 22 of the inflatable shell 16. Similarly,FIG. 8 shows the chambers 6 extending beyond the width of the body portion 11 (designated by the dotted line). The greater size of the chambers 6 relative to the body portion 11 helps to evenly distribute the forces applied to the stomach through the inflation of the gastric band 10.
FIG. 5 shows a close-up view of a notch8 and rib7 of the inflatable shell16. Also shown inFIG. 5 are chambers6 on either side of the rib7. FromFIG. 5 it can be seen that the portions of the inner surface15 immediately adjacent to the notches8 will not come in contact with one another upon inflation of a gastric band10 having a inflatable shell16 so designed. This prevents wear and rubbing of the inner surface15. Also as a result of the notch8, a crease will not form in the inner surface15 of the inflatable shell16. Further, because of this the chamber6 can be inflated to a much greater volume forming a smaller stoma than similar sized gastric bands known in the prior art.
The effects of the notch8 can be described as follows: the notch8 acts as a pre-formed crease in the inflatable shell 16. The notch8 acts similarly to the crease that may form in gastric bands known in the prior art as it provides a point around which the body portion11 is allowed to bend the inner surface15 of the gastric band10 to form a substantially circular band. One with basic geometry skills will understand that the inner surface15 and the body portion11 have substantially similar lengths. As a result of this, if the body portion11 and inflatable shell16 are not pre-formed in a circle, when they are subsequently bent into a circular form, the interior surface15 must in some fashion eliminate a portion of its overall length to form a circle having a smaller inner circumference than outer circumference. This reduction in circumference has heretofore occurred in prior art gastric bands through the formation of undesirable creases on the inner stomach-facing surface of the gastric band, resulting in a reduced range of inflation for such bands. The formation of these creases alleviates the material stresses in forming the circular shape, but causes point loading at the top and bottom of the creases as well as providing a point of friction between two facing sides of the crease. By forming the inflatable shell16 in a circle with pre-formed notches8, the aforementioned stresses are drastically reduced because the notch8, alone or in combination with a rib 7, is formed in a fashion that prevents opposing sides of the notch8 from buckling and reduces stress, while allowing for a great range of inflation versus prior art devices. Additionally, the effects of the point loading associated with the extremities of the crease can be alleviated by the notch8, especially when the notch8 is formed in conjunction with a reinforcing rib7.
In practice, the gastric band is placed in an encircling position around the stomach using known surgical techniques, including, preferably laparoscopy. Laparoscopic placement is accomplished by introducing the fill tube14 through a laparoscopic cannula (not shown) into the patient's abdomen. Laparoscopic placement begins with blunt dissection behind the stomach, usually two to three centimeters below the gastro-esophageal junction. Typically, the end of the fill tube14 and tail end13 are passed around the stomach and drawn through the buckle19, past the exit side20 so that the belt tab17 and buckle19 are releasably locked together. In this sense, the band is a "one-size-fits-all" device-like that described by Vincent-but because of its notched design, the gastric band is adjustable over a greater range without creasing or folding than Vincent and other known prior art bands.
The stoma-the narrow opening in the stomach created by the band-may be adjusted after the band is secured in this single position. Prior art gastric bands employ an adjustable balloon portion that is used for post-operative adjustment of the stoma as necessary. These adjustable balloons, as discussed above, are prone to creasing. The pre-formed notches8, chambers6 and ribs7 of the inflatable gastric band10 described herein provide for increased fill volumes,e.g. up to 10 cc, without wrinkles or folds forming in the shell. As in the Vincent band, the inflatable shell16 is preferably coextensive with the inner stomach-facing surface15 of the band between the belt tab17 and buckle19. The interior of the inflatable shell16 is in fluid communication with an injection reservoir, remote pump, pressure reservoir or other adjustment means (not shown) via fill tube14, as with prior art adjustable gastric bands. The inflatable shell16 is gradually inflated with saline or other biocompatible fluid via the adjustment means such that the inflatable shell16, and in particular the inner surface15 thereof presses on and constricts the stomach underlying the band. This results in a decrease of the opening (stoma) inside the stomach directly under the encircling gastric band10.
During inflation of the gastric band10, the notches8 and the ribs7 resist deflection. At the same time, the chambers6 do not comparatively resist deflection. This results in the areas of the inflatable shell16 where the ribs7 are located forming deeper notches8 upon inflation. Accordingly, these notches8 reduce the stresses in the inflatable shell16 and reduce the potential for crease fold failure by eliminating contact between the two sides of the notch8.
Despite the addition of the notches8 and ribs7, the gastric band10 forms a substantially circular constriction around the stomach upon inflation. The chambers6 of the inflatable shell16 direct the locations of inflation. Because of the greater deflections of the inflatable shell16 in the chambers6 as compared to the area of the notches8 and ribs7, the gastric band10, and in particularly the inner surface15 is prevented from pinching the surface of the stomach between two chambers6 when in its inflated state, thereby reducing the potential for patient discomfort and necrosis.
The gastric band10, as shown inFIG. 1, allows for greater adjustability and fill volume range than current gastric bands, while reducing the potential for fatigue failure, crease fold failure, or pinching of the stomach. Through the use of the chambers 6, notches8, and the elimination of crease points, the inflatable shell16 is provided a greater expandable range and is able to produce a smaller opening without fear of pinching the stomach. Similarly, because the crease points are eliminated, the likelihood of crease fold failure is also reduced. It is the possibility of pinching the stomach, and the potential for crease-fold failure that limit the operable range of currently known devices. The reduction of these possibilities increases the range of the stoma opening that may be formed with a single gastric band, while safely treating the obese patient.
Another embodiment of the present invention is an inflatable gastric band with an inflatable shell that is separated into multiple, isolated inflatable compartments or chambers. The inflation of the isolated chambers may or may not be circular, but will not crease, wrinkle or fold. Each isolated chamber may be inflated separately or simultaneously with other isolated chambers and will expand without creasing, wrinkling or folding. A compartmentalized gastric band allows for even greater adjustability and fill volume ranges than current gastric bands while reducing the potential for fatigue failure or crease fold failure.
For example, it may be desirable to reduce the size of the stoma in a particular direction. In such instances, a chamber on that side of the gastric band could be inflated without changing the size of the remaining chambers.
Accordingly, greater flexibility is available in a device having isolated chambers that may be independently filled and adjusted. Such an arrangement requires independent filling pathways for each chamber.
The design of the present invention has been described for use in gastric banding devices, but may also be incorporated into any inflatable or expandable device that uses silicone or other elastomeric or polymeric materials where there may be a concern over crease fold failure.
Although the invention has been particularly shown and described with reference to certain preferred embodiments, it will be readily appreciated by those of ordinary skill in the art that various changes and modifications may be made therein, without departing from the scope of the claims. It is intended that the claims be interpreted as including the foregoing as well as various other such changes and modifications.