Abstract:
A device for minimally invasive tendon sheath release is presented. The device enables a surgeon to cut (“open”) a pulley that is obstructing a nodule and keeping a tendon from sliding smoothly. The device is generally comprised of a shaft having a guide probe at a distal end and a slidable blade positioned to slide longitudinally from the proximal to the distal end of the device. The device is inserted through a small incision and the guide probe is used to find the edge of the pulley. Once found, the probe is guided to an end of the pulley. After proper position is assured, a cutting blade is deployed by sliding the blade from the proximal to the distal end of the device until the pulley is completely released or where resistance is no longer felt.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a divisional of and claims priority to currently pending U.S. patent application Ser. No. 14/090,714, entitled “Device for Minimally Invasive Tendon Sheath Release having a Static Blade”, filed Nov. 26, 2013, which claims priority to U.S. Pat. No. 8,608,763, entitled “Method for Minimally Invasive Tendon Sheath Release”, filed on Oct. 1, 2010, which claims priority to U.S. Provisional Patent Application No. 61/251,957, entitled “Device for Minimally Invasive Tendon Sheath Release,” filed on Oct. 15, 2009, the contents of each of which are hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a novel device and method for minimally invasive tendon sheath release. More particularly, it relates to a device and method that allows a surgeon to cut (“open”) a pulley that is obstructing a nodule and keeping a tendon from sliding smoothly. 
     2. Description of the Prior Art 
     Tendons that move fingers are held in place on bones by a series of ligaments called pulleys (or sheath). These ligaments form an arch on a bone surface that creates a sort of tunnel through which the tendon extends along the extent of the bone. Triggering is usually the result of a thickening in the tendon that forms a nodule, or knob. The pulley ligament may thicken as well. The constant irritation from the tendon repeatedly sliding through the pulley causes the tendon to swell in this area and create the nodule. 
     The symptoms of trigger finger include pain and a funny clicking sensation when the finger is bent. Pain usually occurs when the finger is bent and straightened. Tenderness usually occurs over the area of the nodule. The clicking sensation occurs when the nodule moves through the tunnel formed by the pulley ligaments. With the finger straight, the nodule is at the far edge of the surrounding ligament. When the finger is flexed, the nodule passes under the ligament and causes the clicking sensation. If the nodule becomes too large it may pass under the ligament and become stuck at the near edge. The nodule cannot move back through the tunnel causing the finger to lock in the flexed trigger position. Surgery may be required to release the trigger finger. 
     Trigger finger and tendon sheath surgery are common procedures that are usually performed in the operating room. Traditional tendon sheath release procedure is performed in an operating room at a hospital or surgery center under conscious sedation—which involves risk to the patient—and using a local anesthetic. The traditional open operation uses a conventional scalpel device and a 1.5 to 2.0 cm incision that disrupts all tissue and skin above the pulley and requires two or three stitches. 
     What is needed is a device and method that allows the operation to be performed in a surgeon&#39;s office safely, quickly, and in a less costly manner than going to the operating room. However, in view of the prior art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the art how the limitations of the art could be overcome. 
     SUMMARY OF INVENTION 
     The long-standing but heretofore unfulfilled need for an improved device and method for minimally invasive tendon sheath release that allows the operation to be performed in a surgeon&#39;s office safely, quickly, and in a less costly manner than going to the operating room is now met by a new, useful, and nonobvious invention. 
     Generally speaking, the claimed invention is a precisely guided scalpel device that allows a surgeon to perform a tendon sheath release procedure safely and quickly in an office. The procedure is performed through an incision about 90 to 95% smaller than a conventional incision while at the same time allowing for minimal dissection of surrounding tissue and a more precise release of the pulley. Probes at the tip of the device allow the user to ensure that the device is appropriately positioned under the pulley and, when this is confirmed under fluoroscopy or ultrasound, the retractable knife portion of the device can be deployed and the pulley safely cut and divided, thereby disturbing much less surrounding tissue than a conventional operation. 
     In a first embodiment, the device includes a handle, a handle cavity, a sliding flag and switch, a sheath extending from the cavity and handle, a retractable shaft within the sheath, a spherical tipped guide probe, and a dorsal outrigger tipped guide. The spherical tipped guide probe attaches to the distal bottom tip of the sheath. The dorsal outrigger spherical tipped guide is attached to the distal top of the sheath. The sheath contains the retractable cutting shaft and is attached to the handle. The handle contains a tunnel that is essentially an extension of the sheath within the handle and extends to the handle cavity. The sliding flag and switch are attached to the retractable cutting blade. The handle slot contains and guides the proximal part of the retractable cutting shaft and its attached sliding flag. The sliding flag links the retractable cutting shaft to the blade deployment switch. The sliding flag and deployment switch essentially form a trigger mechanism for deploying the blade. 
     The dorsal outrigger guide and guide probe have tips that are spherical shaped. However, the tips may be any shape. 
     In an embodiment, the dorsal outrigger guide extends and retracts with the retractable cutting shaft. 
     In an embodiment, the dorsal outrigger guide is angled relative to the sheath, and the guide probe is tapered or curved. 
     In an embodiment, the retractable cutting shaft may include a crochet hook type blade tip. The sheath may also be curved. 
     In an embodiment, the blade is in mechanical communication with the deployment switch via a wire. 
     In alternate embodiment, the cutting shaft is not slidable; instead, the cutting shaft is affixed at the distal end of the sheath between the dorsal outrigger guide and the guide probe. In this embodiment, the trigger mechanism is unnecessary. 
     In an additional alternate embodiment, the shaft is turned up at the tip for placement under the pulley. A sliding blade slides along the shaft dividing the pulley by pushing the sliding blade itself rather than the whole instrument. 
     The method of performing the procedure includes the following steps. First, the involved finger is identified, verified, prepped, and draped in a sterile fashion. Next, 2 to 3 cc of local anesthetic is injected at the level of the A-1 pulley. A 3 to 4 mm incision is made at, or just proximal to, the proximal flexion crease of the finger. A small pair of tenotomy scissors are used to dissect in the subcutaneous tissue above the tendon sheath proximally to the interval between the A-1 and A-2 pulley in the midline of the finger. The spherical tipped guide is inserted into the interval between the A-1 and A-2 pulleys and directed distal to proximal between the A-1 pulley dorsally and the flexor tendons and directed proximally in the direction of the flexor tendon sheath (i.e., toward the valley between the thenar and hypothenar eminences at the carpal tunnel). Once the dorsal outrigger guide engages/passes under the proximal edge of the A-1 pulley, the instrument is wiggled in the plane of the palm to confirm central placement underneath the A-1 pulley. Additional confirmation of the instrument within the tendon sheath may be confirmed by ultrasonic or fluoroscopic imaging. The novel device is then pushed distal to proximal in the direction of the thenar/hyppothenar valley. Resistance is felt as the blade engages and begins to divide the pulley. The instrument is slowly pushed approximately 1 to 1.4 cm at which time a noticeable decrease in resistance is felt signaling the complete division of the pulley. At this point, the instrument is backed out and removed from the wound and the patient is asked to flex and extend the finger to confirm complete division of the pulley. The incision is either closed with a single stitch, a steri-strip, or derma bond glue. A sterile band aid is then placed over the wound. The patient can begin immediate range of motion exercises. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a fuller understanding of the invention, reference should be made to the following detailed description, taken in connection with the accompanying drawings, in which: 
         FIG. 1  is a perspective view of an embodiment of the device utilizing a blade deployment mechanism; 
         FIG. 2  is a top view of an embodiment of the device utilizing a blade deployment mechanism; 
         FIG. 3  is a front view of an embodiment of the device utilizing a blade deployment mechanism; 
         FIG. 4  is a cross sectional side view of an embodiment of the device utilizing a blade deployment mechanism; 
         FIG. 5  is a cross sectional view of an embodiment of the device taken along line  5 - 5  in  FIG. 2 ; 
         FIG. 6  is a cross sectional view of an embodiment of the device taken along line  6 - 6  in  FIG. 4 ; 
         FIG. 7A  is a side view of an embodiment of the device utilizing a crochet hook type blade as stowed; 
         FIG. 7B  is a side view of an embodiment of the device utilizing a crochet hook type blade as deployed; 
         FIG. 8  is an upper perspective view of a commercial embodiment of the device utilizing a blade deployment mechanism; 
         FIG. 9  is a front view of a commercial embodiment of the device utilizing a blade deployment mechanism; 
         FIG. 10  is a side view of a commercial embodiment of the device utilizing a blade deployment mechanism; 
         FIG. 11  is a rear view of a commercial embodiment of the device utilizing a blade deployment mechanism; 
         FIG. 12  is a top view of a commercial embodiment of the device utilizing a blade deployment mechanism; 
         FIG. 13  is a side view of a commercial embodiment of the device utilizing a blade deployment mechanism; 
         FIG. 14  is a bottom view of a commercial embodiment of the device utilizing a blade deployment mechanism; 
         FIG. 15  is a side view of an embodiment of the device having a static blade; 
         FIG. 16  is a side view of an embodiment of the device having a sliding blade; 
         FIG. 17  is a side view of an embodiment of the device having a static blade; 
         FIG. 18  is a side view of an embodiment utilizing a alternate blade deployment mechanism; 
         FIG. 19  is a bottom view of an embodiment utilizing a alternate blade deployment mechanism; 
         FIG. 20  is a side view of a commercial embodiment of the device having a static blade; 
         FIG. 21  is a top view of a commercial embodiment of the device having a static blade; 
         FIG. 22  is a side view of a commercial embodiment of the device utilizing a blade deployment mechanism; 
         FIG. 23  is a top view of a commercial embodiment of the device utilizing a blade deployment mechanism; and 
         FIG. 24  is a side view of an embodiment of the device having the dorsal outrigger spherical tipped guide and retractable cutting shaft  18  as one component. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following detailed description discloses the preferred dimension of an embodiment and shall be interpreted as illustrative and not in a limiting sense. The device is to be commercially known as the trigger tome. 
     Spherical tipped guide probe  12 , as shown in  FIGS. 1-5 , includes an about 2.5 cm long stainless steel spherical tipped probe that tapers from its proximal to distal end, with a proximal round diameter of about 2.5 mm and a distal rounded diameter of about 1.0 mm with an about 3.0 mm diameter spherical tip. Spherical tipped guide probe  12  is attached to the bottom part of sheath  16 . Spherical tipped guide probe  12  is curved. 
     Dorsal outrigger spherical tipped guide  14 , as shown in  FIGS. 1-5 , includes an about 5 mm long by about 1 mm diameter stainless steel spherical tip outrigger that extends from the distal top part of sheath  16  and has an about 2 mm diameter spherical tip at its terminal end. It may extend at about a 20 to 30 degree angle. 
     Sheath  16 , as shown in  FIGS. 1-3 , includes a hollow tube about 6 cm long that has cross-sectional dimensions of about 2.5 mm by 1.0 mm. Sheath  16  contains retractable cutting shaft  18 , as shown in  FIGS. 4-6 . Sheath  16  attaches distally to spherical tipped guide probe  12  and proximally to handle  24 . 
     Retractable cutting shaft  18 , as shown in  FIGS. 4-6 , includes an about 7.5 cm long piece of stainless steel having a cross-sectional dimension of about 0.7 mm by 2.2 mm, with a distal spade or square-shaped highly sharpened tip at the terminal end and connecting to sliding flag  20 . When not deployed, the spade tip resides about 3 mm proximal to the terminal end of sheath  16 . 
     Sliding flag  20 , as shown in  FIGS. 4-6 , includes an about 1.0 mm by 10 mm by 1.5 mm stainless steel flag-like plate that attaches through a weld to retractable cutting shaft  18  inferiorly and is contained within handle  24  and translating about 5 mm proximal to distal within handle cavity  22 . Sliding flag  20  attaches on its superior surface to blade deployment switch  26  by being firmly embedded in a slot in the base of the knob. Sliding flag  20  and switch  26  essentially form a trigger mechanism for deploying cutting shaft  18 . 
     Handle  24 , as shown in  FIGS. 1-6 , includes a knurled plastic or acrylic, round, tubular, solid structure measuring about 2.0 cm diameter and about 7.0 cm in length. Handle  24  contains handle cavity  22  that is oriented in the long axis of device  10 , measuring about 1.5 cm by 1.3 mm by 1.0 cm deep. Handle cavity  22  originates on the surface and terminates at the equatorial center of device  10 . Handle  24  also contains an about 2.5 mm by 1.0 mm slot that contains the proximal extension of retractable cutting shaft  18  that allows it to attach to sliding flag  20 . 
     Handle cavity  22 , as shown in  FIGS. 4-6 , is contained within handle  24  and contains sliding flag  20 . Handle cavity  22  extends radially from the equatorial center of handle  24  about 1.0 cm to the surface. 
     Blade deployment switch  26 , as shown in  FIGS. 1-6 , includes an about 2.0 cm by 0.8 cm by 0.8 cm plastic switch  26  attached firmly to sliding flag  20  and allows the thumb of the device operator to deploy the cutting blade once spherical tipped guide probe  12  is guided into position. 
     Spherical tipped guide probe  12  attaches to the distal bottom tip of sheath  16 . Dorsal outrigger spherical tipped guide  14  is attached to the top of the distal part of sheath  16 . Sheath  16  contains retractable cutting shaft  18  that cuts the pulley tissue when deployed. Sheath  16  is attached to handle  24 , which in turn contains a tunnel (that is essentially an extension of sheath  16  within handle  24 ) and handle cavity  22  that contains and guides the proximal part of retractable cutting shaft  18  and attached sliding flag  20 . Sliding flag  20  links retractable cutting shaft  18  to blade deployment switch  26 . 
     The elements function together to act as a precise cutting guide for the A-1 pulley. Spherical tipped guide probe  12  goes through the small incision subcutaneously and is used to find the edge of the pulley. Once found, probe  12  is guided to the end of the pulley and its position is verified clinically and/or under radiographic or sonographic guidance. After proper position is assured, the cutting blade is deployed by pushing and holding blade deployment switch  26 . This deploys the sharp end of retractable cutting shaft  18  3 mm beyond sheath  16 . Device  10  is then pushed utilizing handle  24  along the pulley about 1 to 2 cm until the pulley is completely released or where resistance is no longer felt. 
     The patient&#39;s finger is anesthetized with lidocaine infiltration using a needle and syringe at the level of the distal palmar crease directly over the A1 pulley and palmar digital crease. A small puncture incision is then made over the palmar digital crease centrally using a #11 blade. Spherical tipped guide probe  12  is introduced centrally and subcutaneously over the tendon sheath and directed down at a 45 degree angle. Through probing with spherical tipped guide probe  12 , the distal edge of the A1 pulley is located and spherical tipped guide probe  12  is passed below the pulley from distal to proximal in line with the flexor tendon until it is felt to push beyond the leading edge of the A1 pulley. The placement of spherical tipped guide probe  12  is verified clinically by wiggling it back and forth in the plane of the operating surface to make sure spherical tipped guide probe  12  is contained in the pulley. The placement of spherical tipped guide probe  12  and avoidance of the digital vessels is then confirmed under ultrasound guidance. Once correct placement is confirmed, the blade is deployed and device  10  pushed centrally and proximally along the A1 pulley completing the release. 
     In an alternative embodiment, as shown in  FIGS. 7A and 7B , the device is made with sheath  16  extending to the level of spherical tipped guide probe  30  and deploys a crochet hook type blade  32  after being passed completely past the A1 pulley through the pulley tunnel. The crochet hooked blade  32  is then deployed and pulled backward to release the pulley from distal to proximal instead of proximal to distal. A trigger mechanism deploys crochet hook type blade  32 . 
       FIGS. 8-14  illustrate a commercial embodiment of the claimed invention. 
     In an alternate embodiment, as shown in  FIGS. 15, 20, and 21 , an affixed cutting blade  40  is located at the distal end of sheath  16  between dorsal outrigger spherical tipped guide  14  and spherical tipped guide probe  12 . In this embodiment, the trigger mechanism is unnecessary. Specifically,  FIG. 15  depicts a static blade  40  at the apex of the two spherical tipped guides. The longer spherical tipped guide is turned up to facilitate placement under the pulley and the whole device is pushed forward to release the pulley. 
       FIG. 16  depicts an embodiment where shaft  16  is turned up at tip  50 . Tip  50  is placed under the pulley and the curved tip locates the end of the pulley tunnel by feel. Sliding blade  60  slides along shaft  16  dividing the pulley by pushing slide blade  60  rather than the whole instrument. 
       FIG. 17  depicts an embodiment of the static or deployable blade  18  which has spherical tips  12  and  14  with small protrusions  70  (or nipples) at the tips to facilitate placement under the pulley and travel through the subcutaneous soft tissues above the pulley. 
       FIGS. 18 and 19  depict an alternate deployment mechanism for extending and retracting blade  18 . Specifically, deployment switch  26  and cutting shaft  18  are in mechanical communication via a lever. 
     Similarly,  FIGS. 22 and 23  depict an alternate deployment mechanism for extending and retracting blade  18 . In  FIGS. 22 and 23 , wire  80  extends through hollow shaft  16  attached to blade  18  allowing it to be retracted to the level of ball  14  so the instrument can be placed safely in the blunt mode and blade  18  deployed and instrument pushed forward to divide the pulley. 
     In an alternate embodiment, as shown in  FIG. 24 , dorsal outrigger spherical tipped guide  14  is disposed at the top, distal end of retractable cutting shaft  18 . Because dorsal outrigger spherical tipped guide  14  is disposed at the top, distal end of retractable cutting shaft  18 , they both extend and retract together as retractable cutting shaft  18  is deployed. Instead of two separate components, the two are essentially formed as one component. 
     In other embodiments, device  10  is used to release other tendon sheaths and slips of tissue in the body by providing safe subcutaneous guidance and subsequent effective cutting. Device  10  can be used unmodified for DeQuervain&#39;s release, posterior tibial tendon release, tarsal tunnel release, and, through a variation of spherical tipped guide probe  12  concept and device size, be used to perform a carpal tunnel release with ultrasound guidance through a small puncture incision and a plantar fascial release. Variations can also be used to perform fasciotomy incisions in the leg and forearm for compartment syndromes. 
     It will be seen that the advantages set forth above, and those made apparent from the foregoing description, are efficiently attained and since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matters contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.