US20080188826A1 - Methods and devices for treating tissue - Google Patents

Abstract

Device and method are provided for diagnosing and treating diseases and injuries to the spine by injecting drugs into-the diseased or injured area. The device and method of the subject invention provide improvements to patient and operator safety, along with ease-of-use and convenience improvements over conventional techniques.

Description

RELATED APPLICATIONS
• This is a non-provisional application of U.S. Provisional Application No. 60/898,953 filed Feb. 1, 2007. The content of which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
• The present invention is drawn to devices and methods for improved injection systems. Variations of the devices and methods of the injection systems provide atraumatic injection delivery within a spinal column while minimizing the likelihood of causing adverse events.
BACKGROUND OF THE INVENTION
• Annually, millions of Americans suffer from significant spine related pain and discomfort. Where the cervical, thoracic, and lumbar vertebrae and discs can be the source of this pain and discomfort. In one estimate, pain perceived in the neck or upper limbs that is caused by irritation in the nerves that exit the cervical spine through the foramen affects a population of approximately 1 person per 1000 per year. As a result, every year physicians in the United States perform an estimated 750,000 transforaminal cervical injections to treat these patients.
• While the nerve irritation and resultant inflammation causing this spinal pain has a variety of etiologies that result in contact between the nerve and the adjacent structures in the spine, transforaminal injections of corticosteroids can relieve this irritation and reduce the accompanying pain.
• Injections of corticosteroids and or local anesthetics into isolated areas of the epidural space are important treatment and diagnostic modalities for patients suffering from spinal pain syndromes. Isolation of the injection to a specific spinal level is accomplished by using a transforaminal approach. This is distinguishable from the traditional trans-laminar approach of spinal epidural injections commonly used for anesthesia.
• Presently, physiatrists, anesthesiologists, radiologists, neurologists, and orthopedic surgeons perform such transforaminal injections under fluoroscopic guidance using a C-Arm fluoroscope, a standard spinal needle, and three 3 cc syringes. One current technique in providing these injections includes conscious sedation of the patient through the use of local anesthetic and anxiolytics. The operator performs the procedure using multi-plane fluoroscopy to guide the needle into position and to verify correct location of the delivery device prior to injection of the substance.
• As shown inFIG. 1, existing delivery devices include a 20-25 gaugehypodermic needle1 that is inserted through the skin, muscle andsoft tissues10. Using fluoroscopy, the operator positions the distal end of the needle immediately adjacent to a portion of avertebral body12 at the level of the desired injection. Typically when delivering the injection in a cervical region of the spine, this includes positioning the tip of the needle immediately adjacent to a posterior inferior aspect of a superiorarticular process14 of a facet joint of thevertebral body12 at an index foraminal level chosen for the injection. Care must be taken to avoid puncturing the vertebral arteries orveins16 extending through foramens in thevertebral body12.
• To test the initial placement of the needle it is standard for the operator to initially inject a contrast media, such as a radio opaque dye. This step is useful to determine whether the needle is undesirably located in ablood vessel16 or in thedural membrane18. To verify whether the needle is desirably placed, the operator observes under fluoroscope for negative indication of veneous, arterial, or cerebrospinal uptake of the dye. Upon confirming the correct location, the needle is left in position while the syringe containing the radio opaque dye is carefully removed from the needle and replaced by a syringe containing a local anesthetic such as lidocaine. As explained below, tie operator must take great care not to avoid any inadvertent movement or advancement of the needle especially during exchange of the syringes.
• The operator then injects a small bolus of lidocaine (or a local anesthetic of choice) and waits a sufficient period (e.g., sixty seconds) to allow for the anesthetic to disperse. During this time the operator observes the patient for adverse reactions resulting from accidental vascular uptake or injection into the dural sleeve or thecal sac. Although placement of the needle was observed using the radiopaque dye, there is still a risk of accidental) vascular injections because the needle may have moved during the syringe exchange process or simply because vascular perforation was not detected during the radiopaque dye injection.
• Once the operator confirms negative adverse reactions, the operator again carefully exchanges syringes to connect a syringe containing a corticosteroid. Finally, the corticosteroid is injected in an effort to reduce: inflammation thereby affording the patient pain relief. After the three injections i.e. radio-opaque dye, local anesthetic, corticosteroid are complete, the needle is removed from the patient.
• Although the current procedure provides benefits to patients having spinal related pain, significant risk remains with the current procedure. One inherent risk includes breaching a blood vessel and the inadvertent injection of dye, anesthetic, and/or corticosteroids into an artery or vein. Currently, it is believed that breaching a blood vessel occurs in a considerable number of injections performed (a recent clinical study had venous uptake in over 19% of injections performed). Additional risks include contact between the injection needle and the nerve root, which may cause pain along with damage to the dura. Finally, there are risks associated to the operator via exposure to the X-Ray radiation of the fluoroscope, particularly in view of the cumulative exposure as the operator must position the needle as well as exchange syringes a number of times.
• The actual breaching of the blood vessel may occur during the initial insertion of the needle into the site, subsequent manipulation of the needle during syringe exchanges, or even movement of the needle as a result of the force applied by the operator during actuation of the syringe. In some cases, injection into a blood vessel may occur even if the needle has not penetrated the vessel wall as the force of the injectant flowing out of the distal tip of the needle can be sufficient cause the injectant to breach the blood vessel wall and enter into the vessel.
• Complications from accidental injection of the anesthetic into the vessel can include transient paralysis of the spinal cord. Complications resulting from accidental injections of corticosteroids into blood vessels can include permanent paralysis, permanent blindness (if injected into a vertebral artery), seizures, permanent cognitive dysfunction, physical impairment, and/or death.
• Another complication associated with transforaminal injections is inadvertent contact between the needle and nerve root which may cause pain or tingling emanating through the upper extremities. If the needle perforates the dural sleeve, spinal fluid may leak resulting in a transient headache lasting from several hours to several days. If local anesthetic is injected into the thecal sac, temporary paralysis may occur that could result in a cessation of breathing, necessitating emergency intubation of the patient.
• In view of the above risks, to ensure patient safety the operator must reposition the needle if he or she suspects that patient harm could occur. In addition, if arterial uptake is suspected, a common recommendation is that the procedure should be abandoned to allow the arterial perforation to heal and to obviate the risk of injury to the spinal cord resulting from inadvertent injection of corticosteroid into the radicular artery or vertebral artery.
• Each time the needle is repositioned, a new X-Ray image must be captured to verify the needle position and additional real time fluoroscopy images must be captured with an additional injection of contrast media. The additional fluoroscopy and associated radiation exposure presents an increased risk to the operator performing the procedure. To minimize exposure the operator must step toward and away from the radiation field to alternately maneuver or manipulate the hypodermic syringe and allow fluoroscopic images to be taken. This exertion combined with the repeated connecting and disconnecting of syringes contributes to operator fatigue, which is not a trivial consideration for operators performing multiple procedures in a particular day.
• The design of the current devices presents an additional problem that contributes to undesired device placement. Current devices include rigid and straight hypodermic needles. Such a configuration limits the operator to only work within the “line of sight” from the surface of the skin along an axis of the needle. In many cases, it is desirable to perform the injection in a position that is not directly accessible by a straight, rigid needle, e.g., it is frequently desirable to inject medicine in a position “behind” portions of the vertebra, nerves, or blood vessels, (i.e. around the corner from the line of sight position).
• Devices and methods are provided herein for a transforaminal epidural injection needle system that minimizes the above risks to improve patient safety. In addition, the benefits of such devices reduce operator fatigue and decrease the operator's potential radiation exposure.
• The methods and devices may be used for transforaminal selective epidural injections to the cervical, thoracic, or lumbar spine. Fluoroscopically guided, contrast-enhanced transforaminal epidural injection procedures help to specifically evaluate and treat the precise spinal nerve involved as a source of spinal and referred extremity pain. Although therapeutic and diagtiostic transforaminal epidural injections have been performed for decades, the equipment used for these injections has been relatively unchanged during that time.
SUMMARY OF THE INVENTION
• The present invention incorporates features that address each of the risks listed above. The devices and methods described herein include a catheter with a blunt distal tip and an injection port that allow drugs or other substances to disperse at a target site while minimizing safety concerns. The construction of the catheter decreases the chances of inadvertently injecting substances into a blood vessel as well as inadvertently damaging structures because of incorrect placement of a needle.
• The invention includes an injection system comprising a needle cannula having a sharp tip at a far end of the needle cannula, where the sharp tip is adapted to penetrate tissue, and a needle lumen extending through needle cannula. The device includes a sliding member slidably affixed within the needle lumen to move between a retracted position and a deployed position within the needle lumen. This sliding member may be a plunger, a stop surface, or any such structure. In additional variations, the sliding member can be non-rotational (e.g., such as having a groove or keyway) so that the injection tube injection port is always oriented relative to the cannula. In yet another variation, the sliding member can provide information relating to the orientation of the catheter tubing to the physician via markings, etc. An injection tubing having a distal portion having a distal end, a proximal portion, and an injection lumen extending between the distal portion and the proximal portion, where the injection lumen exits the injection tubing at an injection port located in a sidewall in the distal portion; where the injection tubing is affixed to the sliding member such that when the sliding member is in the: proximal position, the distal portion is within the needle cannula and when the sliding member advances to the deployed position, the distal portion of the injection tubing extends out of the far end of the needle cannula. Given that the sliding member is affixed to the injection tubing, the injection tubing can be moved a limited distance by advancement or retraction of the sliding assembly. The benefits of such a feature are described below. An embodiment of the system also includes a plurality of independent extension tube lumens where a manifold fluidly couples each of the extension tube lumens to the injection lumen.
• The invention further includes methods of delivering substances into an epidural space using one of the variations of the devices described. In one variation the invention includes methods of delivering substances into a spine, epidural space, spinal canal or similar region of the body.
• In one variation, the methods include a needle cannula having a needle lumen and an injection tubing extending through the needle lumen, where the injection tubing comprises an injection lumen, fluidly coupling a source of a radiopaque material to the injection lumen and independently fluidly coupling a source of a first therapeutic substance to the injection lumen, where such coupling occurs prior to inserting the needle cannula into the patient, inserting a distal end of the needle cannula so that it is spaced a distance from the epidural space, advancing the injection tubing through the needle cannula to advance a tip of the injection tubing from the distal end of the needle cannula to the epidural space, delivering the radiopaque material through the injection lumen to the epidural space to verify placement of the tip of the injection tubing, and delivering the first therapeutic substance through the injection lumen to the epidural space without disconnecting the source of the radiopaque material from the needle lumen.
• In yet another variation, the method includes providing an injection system including a needle cannula having a needle lumen extending therethrough and an injection tubing having a curved shape at a distal portion, where the injection tube is slidably located in the needle lumen to move between a retracted position and a deployed position, where in the retracted position the injection tubing remains within the needle lumen and in the deployed position, the injection tubing extends out of a far end of the needle cannula to curve away from an axis of the needle cannula, advancing a tip of the needle cannula into the patient so that the tip is positioned adjacent to the vertebral body and spaced a distance from the foramen of the vertebral body, advancing the distal end of the injection tube around a feature of the vertebral body into the foramen by advancing the injection tube within the needle cannula such that the distal portion exits the injection tube and assumes the curved shape.
• The injection system may deliver injectants, injectable substances, and/or injectable fluids. Such substances are intended to include any medication or diagnostic fluid the physician (or operator) may choose to administer with the system.
• It is noted that the invention includes combinations of embodiments or aspects of the embodiments themselves. The following illustrations are intended to convey an overall concept of the inventive methods and devices.
• This application is also related to commonly assigned U.S. application Ser. No. ______ entitled Methods and Devices for Treating Tissue filed Aug. 14, 2007 (Attorney Docket No. LRMD-N-Z002.00-US). The entirety of which is incorporated by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
• The invention is best understood from the detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not to-scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawings are the following figures:
• FIG. 1 illustrates a previously known procedure for injecting a substance within a spinal canal of a patient.
• FIG. 2A shows a cross sectional view of an example an injection system incorporating the concepts discussed herein.
• FIG. 2B shows a cross sectional view of the injection system ofFIG. 2A where the catheter or injection tube is withdrawn into the needle cannula.
• FIG. 2C shows a cross sectional view of another variation of an injection system without, a plunger mechanism.
• FIG. 2D shows a cross sectional view of the injection system ofFIG. 2C where the catheter or injection tube is advanced out of the needle cannula.
• FIGS. 3A to 3B illustrate an example of placing and deploying the injection systems according to the devices and methods described herein.
• FIGS. 4A to 4D show additional variations of injection systems where a manifold is located on a body of the device.
DESCRIPTION OF THE INVENTION
• FIG. 1 illustrates a variation of aninjection system100. Although the systems and methods described herein are often described as being used as a cervical injection system or for the cervical region of the spine, the device and methods may be applied in a broader and to various other parts of the spine as well as anatomic structures where the features of the system may provide useful.
• As shown inFIG. 1, thesystem100 includes a cannula orneedle cannula102 where adistal tip104 of theneedle cannula102 is sharp so that an operator may advance thecannula102 through tissue to reach the intended target site. Theneedle cannula102 may optionally include ahub106. Thehub106 may be a common polymeric hub that is molded, bonded, or otherwise affixed to theneedle cannula102. Alternatively though not shown, thehub106 may comprise a section of theneedle cannula102 itself. In any case, in some variations of thesystem100, thehub106 provides an ergonomic surface for the operator to grip during insertion and potentially manipulate with a single hand. The shape of the hub (and device body as described in additional variations below) should enable the operator to hold the hub and/or device between their thumb and forefinger of each hand. This improves the operator's ability to aim and guide the needle (and ultimately the catheter/injection tubing) into position. Additionally, this design shape allows the operator excellent tactile feedback during insertion of the device and advancement of the injection tubing.
• In one example, when thesystem100 is optimized for use in delivering injections in the spinal area, the needle cannula can be any standard needle. In spinal applications the cannula can be 19 to 26 gauge. In one variation useful for cervical region treatment, a 22 Ga needle having a length of 2.5 inches was developed. However, alternative variations of the invention include needles of varying lengths, gauges, as well as cross-sectional shape. As shown, theneedle cannula102 extends only partially into thehub106. However, variations also include aneedle cannula102 that extends through thehub106.
• In any case, theneedle cannula102 includes aneedle lumen108 through which a catheter orinjection tubing110 extends. Although not illustrated, theinjection tubing110 includes an injection lumen extending therethrough and exiting at aninjection port112 in a wall at adistal portion114 of theinjection tubing110. In additional variations, the device can include an injection port at a distal end of theinjection tubing110. In addition variations of devices disclosed herein can include more than one injection port.
• Theinjection tubing110 can be made of a flexible material such as any polymeric or composite material used for medical device applications. In addition, the catheter tubing can have elastic characteristics (e.g., flexible polymers, coil or other reinforced catheters, or super-elastic/shape memory characteristics), that allow the device to curve slightly around or deflect away from structures such as blood vessels, nerves, or bone to optimally position the orifice for the injections. The elastic characteristics may come from the properties of the tube, an elastic wire that is extruded within the wall of the tube, or even an elastic stylus that temporarily resides in the lumen of the tubing. In some variations of the system, the curve of the distal portion of the catheter tubing also enables the operator to “steer” the catheter by orienting the distal tip such that the catheter tends to follow a particular direction.
• Placing theinjection port112 in a side wall and not at adistal end120 prevents the likelihood that fluid ejected from thedevice100 will cause inadvertent damage to the patient. For example, even if adistal tip120 of thesystem100 pierces a vessel or the dura, then the proximal spacing of theinjection port112 reduces the likelihood that the injected fluid would actually enter the structure as the fluid will be injected proximal to the entry point. In other words, it would be necessary for the entiredistal portion114 of the injection tubing110 (from theinjection port112 to thedistal tip120 to cannulate the vessel or dura. In the variation shown, theinjection tubing110 also includes one or more visualization marker(s)126. For example, a singleradiopaque marker126 can be placed adjacent to theinjection port112 so that the operator may precisely locate the proximity of theinjection port112 to a vessel or other structure. Yet another feature that improves safety is placement of theinjection port112 on an interior radius or aspect of the curveddistal portion114 of theinjection tubing110. As fluid disperses from theinjection port112, because theinjection port112 is on the interior curve of thedistal portion114 of theinjection tubing110, the fluid is delivered away from the dura or other nerve structures (as will be discussed below). However, additional variations of the invention contemplate placing aninjection port112 anywhere along the distal portion of theinjection tubing110.
• Systems100 of the present invention also include a sliding member, in this variation the sliding member is aplunger122 slidably affixed within a lumen of theneedle cannula102 and secured to theinjection tubing110. This construction permits movement of theplunger122 to advance or retract theinjection tubing110. Since theplunger122 is slidably affixed within theneedle cannula102, theplunger122 can move between a proximal or retracted position (where thedistal portion114 of the injection tubing is retracted within the needle cannula) and a distal or deployed position (where thedistal portion114 of theinjection tubing110 is deployed from theneedle cannula102 as shown inFIG. 2A).
• FIG. 2B illustrates a distal section of thesystem100 showing theplunger122 in a retracted position causing thedistal portion114 of theinjection tubing110 as well as theinjection port112 withdrawn into thecannula102. As discussed below, configuring theinjection tubing110 to advance in and out of thecannula102 improves the ability of the operator to safely locate thetip104 of thecannula102 while advancing theinjection tubing110 andport112 to a desired location for delivery of the substances. This feature of thesystem100 is discussed in further detail below. Alternate variations of the invention can include plungers that are removeable from theneedle cannula102. Theplunger122 may comprise a simple tube structure. In some variations of thesystem100, the fit between theinjection tubing110 andneedle cannula102 allows a tactile “feel” of the resistance as the catheter is advanced to the injection site. This feature helps the operator feel whether the tip of the device encounters any structures as it advances to the target site.
• In the variation shown inFIG. 2A aproximal portion116 of theinjection tubing110 extends from theplunger122 to amanifold126. The manifold126 allows fluid coupling of any number ofextension tubes128 having separate lumens to the lumen of theinjection tubing110. Although the variation shows threeseparate extension tubes128, variations of the device may include a single extension tube with a plurality of independent lumens. The independent liens should allow coupling of thesystem100 to independent fluid sources50 (typically syringes or other such storage vessels). The number of lumens may be any number greater than 1. However, when thesystem100 is used for treatment of spinal conditions, thesystem100 will typically include three separate extension lumens so that three separate fluid sources (e.g., a source of a contrast agent, a source of an anesthetic, and a source of an anti-inflammatory substance such as a corticosteroid). As shown, theextension tube128 can include a luer orother fitting130 on the proximal end to allow coupling to a fluid source. Moreover, variations of the device include use of a valve fitting130 to prevent retrograde flow between syringes.
• One advantage of having separate lumens for coupling syringes or fluid sources is to maintain segregation between the injectable substances. The use of multiple tube lumens reduces the amount of residual substances that must clear the device during subsequent injections. This reduces risk of injecting the patient with an excessive amount of any substance or inadvertent injection of an incorrect substance.
• In certain variations of thesystem100, the length from theplunger122 to thefittings130 is sufficient so that fluid sources (e.g., syringes) can be coupled to thesystem100 and set aside prior to insertion of theneedle cannula102 into a patient. In addition, a sufficient length allows the operator to inject the fluids without excessive exposure to radiation generated by x-ray or fluoroscopic equipment. Although not shown, variations of thesystem100 include the use of strain relief sleeves or collars to prevent crimping or folding of theinjection tubing110 at or near the end of theplunger122.
• The operator prepares thesystem100 for the procedure by attaching three syringes to the device simultaneously prior to insertion into the patient. Naturally, an operator may choose to attach the syringes to tiesystem100 after injection of the cannula into the patient; however, this increases the chance of movement of the cannula subsequent to initial placement. Theinjection tubing110 is advanced distally from the tip of the needle (as shown inFIG. 2A) and air is purged from the all of fluid lines by actuating the syringes containing the substances to be injected (e.g., corticosteroid, anesthetic, and contrast media). Naturally, the injection tube lumen should be charged with the first substance to be injected into the patient.
• The individual syringes can contain a contrast agent such as a radio-opaque dye, a local anesthetic such as Lidocaine, and a corticosteroid. Alternatively, any plurality of lumens and extension tubes could be use in this method were it practical or to the advantage of the operator to have a separate delivery of a plurality of other substances/injectants other than those mentioned above.
• After the purging and charging sequences are completed, theinjection tubing110 is retracted into theneedle cannula102 and the operator may now insert thecannula102 into a patient to provide treatment.
• FIGS. 2C and 2D illustrate another variation of a distal section of thesystem100 where the sliding member comprises astop surface132 that is entirely within thehub106 of thedevice100.FIG. 2C illustrates theplunger122 in a retracted position causing thedistal portion114 of theinjection tubing110 as well as theinjection port112 to be withdrawn into thecannula102. As illustrated, thestop surface132 is affixed to theinjection tubing110 and is slidably moveable within thehub106. As shown, when thestop surface132 is retracted towards aproximal portion107 of thehub106, the internal construction of thehub106 prevents further withdrawal of theinjection tubing110 since the stop surface is affixed thereto. As noted above, thestop surface132 can include a key/groove interface with the interior of the hub to prevent rotation of the injection tubing.
• FIG. 2D illustrate distal advancement of thestop surface132 against adistal portion109 of thehub106. Again, since thestop surface132 is affixed to the injection tubing, distal advancement of theinjection tubing110 is prevented once thestop surface132 encounters thehub106. As shown, in the distal most position, the injection tubing extends from the cannula102 (and optionally curves as shown).
• In those variations, where theinjection tubing110 does not include a plunger, the physician simply advances the injection tubing, manifold, or extension lines, to advance adistal portion114 of the injection tubing from thecannula102. As noted above, the variation shown inFIGS. 2C and 2D can include a single injection or extension tube, or may include a number of injection tubes fluidly coupled to a lumen of the injection tube.
• As shown inFIG. 3A, the needle is positioned in the patient under fluoroscopic guidance in the manner described in the conventional procedure, with the exception that thedistal tip104 of the cannula is positioned approximately 5 mm proximal to the intended target site (typically the epidural space or spinal foramen). This position keeps thesharp tip104 away fromcritical vasculature16 andnerves20. As shown, theplunger122 is in a proximal or retracted position, which maintains the distal portion of theinjection tube110 within thecannula102. The operator can confirm placement of thecannula102 by injecting the contrast agent or dye in the manner described above or by simply observing thecannula102 under fluoroscopy or x-ray.
• The operator can holds thehub106 and/or thecannula102 while advancing the device through the skin and soft tissue. Once positioning of the cannula is properly determined, the portion of thecannula102 or thehub102 can be secured to the exterior skin or operating table in such a manner as to stabilize it from penetrating deeper or withdrawing from the patient, or moving laterally. A second method of stabilization may be an adhesive pad with an integrated clamp that adheres to the patients' skin and stabilizes the needle relative to the patients' skin.
• Once thedistal tip104 of thecannula102 is in position and clamping or adhesive pads are applied the operator is ready for advancing the injection tube. As shown inFIG. 3B, the operator advances theplunger122 causing advancement of theinjection tube110 to the target site (in one variation thesystem100 allow advancement of thetip120 of the injection tube 5 mm to the site). As discussed herein, variations of the device include aninjection tube110 having a slight radius or curve at adistal portion114 that enables advancement of thedistal portion114 along a curved path that is biased toward the posterior aspect of the foramen. This curved position keeps theinjection tube110 safely away from the vasculature and the nerve root which reside in the proximity of the injection site. Additionally, there is a reduced likelihood that theinjection tube110 will penetrate vessels if it engages the vessels during advancement due to the features of theinjection tube110. As noted above, variations of the injection tube includes ablunt tip120. In addition, variations of the device used in spinal applications shall be flexible.
• Theinjection port112 is located away from the distal tip120 (in one example the injection port is spaced 2 mm away from the tip, but any spacing that places theinjection port112 on the distal portion of the device is contemplated.) This feature prevents inadvertent vascular uptake since it would be necessary to cannulate the distal portion of the injection tube within the blood vessel over a distance long enough to envelope the injection port as well. Furthermore, in those variations where the injection port is placed on an interior radius or aspect of the curved distal portion, fluid delivery occurs towards a portion of thevertebral body12 rather than against a vessel or nerve.
• Prior to delivery of the substances, the operator can also observe, under fluoroscope, the position of thedistal portion114 of theinjection tube110 and even the placement of theinjection port112 by observing the position of one or more radiopaque markers on the distal portion. As noted above, some variations include placing a radiopaque mark or indicator directly adjacent to the injection port thereby enabling the operator to see the exact position where the injection will occur.
• After verifying the correct position of the injection tube and injection port, the operator continues in the same sequence as the conventional procedure described above. For example, the operator injects radio-opaque dye into the site to verify the tip of the injection tubing is in the correct location and that a blood vessel was not inadvertently breached as evidenced by the uptake of radio-opaque dye into the vessel. Next, an injection of a test dose of local anesthetic such as lidocaine is administered followed by a sixty second waiting period before a second lidocaine dose and or corticosterdid is injected. The lidocaine is injected first and patient observed to ensure that there has not been intravascular, especially intra-arterial uptake.
• As noted herein, because all three syringes can be attached to thesystem100, it is not necessary to exchange syringes between injection sequences. This feature not only improves operator convenience and reduces finger fatigue from the syringe exchange, but more importantly, it improves patient safety by reducing the likelihood of inadvertent cannula movement during syringe exchanges. In addition, placement of the syringes outside of the surgical field or away from the fluoroscope. Operator safety is further improved because the physician administering the injections may perform the injection of contrast media safely away from the injection site while using real time direct fluoroscopy. This reduces operator cumulative exposure to X-Ray radiation hazards.
• After the injection sequence is completed, thecannula102 can be removed from the injection site with or without theinjection tube110 retracted into thecannula102.
• The volume of fluid in the common fluid path of the catheter system (the volume of fluid that remains between the manifold and the injection port of the injection tube), is considered insignificant. In one variation of a system for cervical, injection, this volume is approximately 0.02 ml whereas the typical injection volume of anesthetic is 0.5 ml (0.4% flush volume), and the injection volume of steroid is 2.0 ml (0.16% flush volume). Both of these flush volumes are within the “noise level” of operators' ability to administer a measured dose of injectants. Therefore, it is not necessary to flush the common fluid path between injections, (e.g. between radiopaque dye, anesthetic, and corticosteroid).
• Although the examples discussed herein, primarily relate to injection systems suited for injections in the cervical region of the spine, the features of the system may be used for spinal treatments in the lumbar and thoracic regions as well.
• FIGS. 4A-4D illustrate another variation of asystem100 according to the concepts of the present disclosure. In this variation, the manifold is directly coupled to adevice body142.
• As shown inFIG. 4A, the components of this variation include acannula needle102, a catheter or injection tube (not shown inFIG. 4A) coupled to aplunger122, adevice body140, a manifold126, extension lines ortubes128,luer connectors130. As noted above, in additional variations, an internal stop surface located within thehub106 can replace theplunger122.
• FIG. 4B illustrates a cross sectional view of the system of4A. As shown, thebody140 of theinjection system100 may be cylindrical in shape for ease of manipulation. The manifold126 can extend from the side of the body13 to permit the flow of injectables (as discussed above) from theextension lines128 into theinjection tube112. The extension lines128 may be a single multi-lumen cross-section or may comprise the plurality of individual tubes shown. As discussed herein, the manifold126 combines the flow of injectables from a plurality of sources (e.g., syringes) into asingle injection lumen118 for delivery through theinjection port112. Naturally, there will be sealing members144 (such as o-rings) to prevent leakage of fluids from the interior of thebody140.
• In this variation, theplunger122 can have any shape, but shall have a portion slidably affixed within the interior of thedevice body130. An upper portion of theplunger122 extends out of thedevice body130 allowing for an operator to actuate or slide the injection tubing in and out of thecannula102. Theplunger122 is affixed to theinjection tubing110 on its lower end with a lumen extending from the catheter to the sealed cavity within the lumen of the body cylinder to allow the injectable fluids to flow from the manifold into the catheter. The upper portion of theplunger122 that extends out of top of thebody140 allows the operator to grip the plunger between their forefinger and thumb, thus providing a tactile “feel” of the resistance as the catheter is advanced to the injection site. However, as noted above, the upper portion of theplunger122 can simply comprise shrink tubing that covers the plunger and extends over an inch or so of theinjection tubing110 to act as a stress relief. Similar stress relief structure can also be placed over the tip of the manifold to provide stress relieve the catheter on that end as well. Injectants, injectable fluids, and so forth are defined as any medication or diagnostic fluid the physician may choose to administer with the system.
• In many variations of the device, the plunger has a limited stroke. This limited stroke allows for a known and finite advancement of thedistal portion114 of theinjection tube110 out of thecannula102. In the variation shown, theplunger122 has a stop on an exterior surface in the form of a raisedsurface124. Alternatively, or in combination, a stop surface can be located on the injection tube, or even on the plunger portion that is interior to thehub106. Naturally, any number of configurations is contemplated.
• A flexible catheter orinjection tube110 resides within thecannula needle102 and has a rounded or bluntedtip120 with an injection port ororifice112 on the side of thecatheter110 near thedistal portion114. As noted above, catheter tubing of the present devices can be made from a flexible material those known in medical device applications and may have shaped memory characteristics that allow it to curve slightly around or deflect away from structures such as blood vessels, nerves, or bone to optimally position the orifice for the injections. The shape memory characteristics may come from the plastic properties of the catheter, an elastic wire that is extruded within the wall of the catheter, or an elastic stylus that temporarily resides in the lumen of the catheter.
• Again, theinjection tubing110 includes aninjection port112 located on the side of thecatheter tubing110 to further reduce the likelihood of accidental injections into an artery.
• Any of the variations discussed herein may include a clamp-stabilizer as an accessory device that holds the system stable relative to the neck. One embodiment of the clamp-stabilizer includes an adhesive pad that attaches to the body of the patient at the point of insertion. When the needle is in place, the clamp is activated to hold the needle stable relative to the patient.
• One embodiment of the clamp-stabilizer includes a structure that attaches to a datum on the bed or bench where the patient is lying. The needle is positioned at the operative site and the clamp is activated to hold the needle steady as long as the patient does not move relative to the datum.
• The flow path of the injectable fluids starts in the syringes attached to theconnector130. The tubing may be multi-lumen tubing or individual tubes. The fluid flows from the syringes through their respective individual lumens in the tubing and into the manifold on the side of the device body. The fluids then flow into interior cavity of the device body, into the plunger body, through the catheter and out the injection port on the side of the catheter near its distal end. An alternate variation includes a piece of tubing that connects the manifold directly to the proximal end of the catheter tubing thereby bypassing the interior of the device body.
• As noted above and as shown4C and4D thesystem100 may optionally include astylus142. Thestylus142 is can be incorporated into theinjection tube110 to aid in steering a tip of theinjection tube110 to a desired region. In an alternate variation, thesystem100 includes a stylus that extends from inside the distal tip of the catheter tubing through the lumen of the catheter, through the body of the cylinder and exits the device through a membrane seal on the proximal surface of the plunger. The stylus is used by the operator to push the catheter out of the distal tip of the primary needle and into the injection site. The stylus could optionally have a curvature that translates its' curvature to the catheter to help steer the tip of the catheter along a curved path and into a position that is not accessible by a straight, rigid needle.
• When the catheter tube is in position at the injection site, the stylus would be removed from the catheter to allow the injectants to flow through the catheter. The stylus may be supplied in a variety of curvatures to allow the operator to select the appropriate curvature to steer the catheter into position based on variations in anatomy or various injection modalities. Alternatively, the stylus may be constructed of a malleable material that allows the operator to shape the stylus to a custom curvature.
• An alternate device embodiment would include a balloon on the tip of the catheter. The balloon would be inflated via a lumen in the catheter and would be used to anchor the catheter in place, dissect tissue, or steer the catheter by positioning the balloon on one side of the catheter such that it pushes the orifice of the catheter toward a particular injection site.
• Before the present devices and method of treatment are described, it is to be understood that this invention is not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.
• Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limits of that range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated or intervening value, in that stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range, and each range where either, neither or both limits are included in the smaller ranges is also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.
• Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, some potential and preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. It is understood that the present disclosure supercedes any disclosure of an incorporated publication to the extent there is a contradiction.
• It must be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “an aerosol” includes a plurality of such aerosols mid reference to “the drug” includes reference to one or more drugs and equivalents thereof known to those skilled in the art, and so forth.
• The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed.

Claims (22)

1. An epidural injection system comprising:

a needle cannula having a sharp tip at a far end of the needle cannula, where the sharp tip is adapted to penetrate tissue, and a needle lumen extending through needle cannula;

an injection tubing having a distal portion having a distal end, a proximal portion, and an injection lumen extending between the distal portion and the proximal portion, where at least the distal portion is flexible and where the injection lumen exits the injection tubing at an injection port, where the injection tubing is moveable within die needle lumen and limited to extend out of the needle lumen by a fixed distance; a sliding member affixed to the injection tube such that a sliding movement of the injection tubing limits a stroke of the injection tubing to the fixed distance such that when the injection tubing is in the proximal position, the distal portion is within the needle cannula and when the injection tubing advances to the deployed position, the distal portion or the injection tubing extends out of the far end of the needle cannula; and

a connector on the proximal portion of the injection tube for coupling the injection tube to a fluid source.

2. The epidural injection system ofclaim 1, further comprising at least one radiopaque marker adjacent to the injection port.

3. The epidural injection system ofclaim 1, where the sliding member comprises a plunger member.

4. The epidural injection system ofclaim 1, where the sliding member comprises a stop surface.

5. The epidural injection system ofclaim 4, where the stop surface is entirely within a hub of the needle assembly.

6. The epidural injection system ofclaim 1, where the injection port is located in a sidewall of the distal portion of the injection tubing.

7. The epidural injection system ofclaim 1, where the sliding member is rotatable to less than 360 degrees about the injection tubing.

8. The epidural injection system ofclaim 1, where a frictional interface between the sliding member and injection tube against the needle lumen is minimized.

9. The epidural injection system ofclaim 1, the connector comprises a plurality of extension tubes each having a lumen, where each of the extension lumens are fluidly coupled to the injection port lumen.

10. The epidural injection system ofclaim 9, where a manifold fluidly couples the extension lumens to the injection port lumen.

11. The epidural injection system ofclaim 9, where the manifold is located in a hub of the injection tubing.

12. The epidural injection system ofclaim 9, where a length of the injection tubing between the manifold and plunger member is sufficient to prevent movement of the needle cannula during manipulation of the extension tubes.

13. The epidural injection system ofclaim 1, where the distal portion of the injection tubing has a curved shape, such that when the distal portion is within the needle cannula, the curved shape deforms to straighten and when the distal portion extends out of the far end of the needle cannula, the distal portion deflects away from an axis of the needle cannula.

14. The epidural injection system ofclaim 13, where the injection port is located on an interior of the curve of the injection tubing.

15. The epidural injection system ofclaim 1, further comprising a hub located at a near end of the needle cannula, where the hub allows for manipulation of the needle cannula.

16. The epidural injection system ofclaim 15, where the hub comprises a surface of the needle cannula.

17. The epidural injection system ofclaim 1, where the distal end of the injection tubing is blunt.

18. The epidural injection system ofclaim 1, further comprising a radiopaque marker at the distal portion of the injection tubing.

19. The epidural injection system ofclaim 1, further comprising a plurality of independent extension tube lumens fluidly coupled to the injection lumen.

20. The epidural injection system ofclaim 19, where the plurality of extension tubes comprise three extension tubes, and where each extension tube is coupled to a syringe.

21. The epidural injection system ofclaim 19, where a length of each extension tube is sufficient such that the proximal end of the extension tube can be removed from a surgical field.

22. The epidural injection system ofclaim 1, where a distance between the retracted position and the deployed position sufficient to advance the distal end of the injection tubing at least 3 mm beyond the far end of the needle cannula.

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