The Case Study section presents various challenging nerve-related case scenarios with the objective to describe management courses, reported outcomes, and the latest clinical advances in nerve reconstruction. The case studies section is currently organized in chronological order while under development and publication. Refer to the key below for various report types.
Key:
(P) Partial Figure Report – A report that contains only figures and videos.
(A) Abbreivated Report – A report that contains a descriptive overview that is supported with figures and videos.
(F) Full Report – A detailed report that describes the case in its entirety and includes information about case histories, examinations, managements, outcomes, and discussions. This report is supported with figures and videos.
November 2011
Title: Early Effects of Foot Therapy and Correction of Foot Posture for Tarsal Tunnel Syndrome.
PNS ID: 111123-1, Published: 11/23/2011, Updated: 12/12/2011.
Author(s): Lawrence Zieske BA, Andrew Yee BS, Susan E. Mackinnon MD.
Division of Plastic and Reconstructive Surgery, Washington University School of Medicine, St. Louis, MO.
Abstract: This 48-year-old woman presented with a three- to four-year history of severe bilateral foot pain that was worse on her left compared to the right side. On examination, the patient had flattened arches and a positive scratch collapse test over the tarsal tunnel on both feet. No Tinel’s sign was present over the tarsal tunnel. Electrodiagnostic studies were suggestive of mild tarsal tunnel syndrome. Foot physical therapy was issued to treat this patient’s symptoms of tarsal tunnel syndrome. This therapy emphasized correcting the positioning of the foot to relieve compression of the tibial nerve through the tarsal tunnel. Exercises included flexion of the foot intrinsic muscles, foot balance, and standing heel raises. After two months of therapy, this patient showed improvement in her symptoms with greater relief of pain on the left compared to the right side. The scratch collapse at the tarsal tunnel was negative on the left, however it was still positive on the right. The patient continues foot physical therapy for improvement of foot posture. This early report describes the use of foot physical therapy to improve the positioning of the foot for relief of symptoms from tarsal tunnel.
Figure 1 – Pain evaluation pre- and post-foot therapy. (A) This patient had a three- to four-year history of severe bilateral foot pain, more so on the left compared to the right foot. She was instructed in foot exercises to treat mild tarsal tunnel syndrome by strengthening intrinsic foot muscles and improving foot posture. (B) This post-therapy pain evaluation was reported at two months into foot therapy, which primarily focused on the left foot. The pain levels were significantly reduced on her left compared to her right foot.
Figure 2 – Post-therapy standing foot positions. This patient demonstrated foot positioning after two months of foot therapy for mild tarsal tunnel syndrome. Her therapy focused primarily on the left foot. (A) Her right foot was slightly pronated compared to the left foot. (B) Her left foot showed less pronation compared to the right foot.
Figure 3 – Foot therapy exercises to correct foot postures associated with tarsal tunnel syndrome. This patient demonstrated foot positioning after two months of foot therapy for mild tarsal tunnel syndrome. Her therapy focused primarily on the left foot. (A) Her right foot was slightly pronated during toe flexion. (B) Her left foot was less pronated compared to her right foot during toe flexion.
June 2011
Title: Hand Intrinsic Muscle Cramping and Mild Atrophy Related to an Aberrant Abductor Digiti Muscle
PNS ID: 110609-1, Published: 6/9/2011, Updated: 6/9/2011.
Author(s): Andrew Yee BS, Susan E. Mackinnon MD.
Division of Plastic and Reconstructive Surgery, Washington University School of Medicine, St. Louis, MO.
Figure 1 – Incision for Guyon’s canal and carpal tunnel release with aberrant muscle finding. Figure 1 – Incision for Guyon’s canal and carpal tunnel release with aberrant muscle finding. The patient reported having mild tremoring in the right hand and intermittent cramping in the intrinsic muscles two years pre-operatively. Ultrasound findings include an aberrant muscle within Guyon’s canal that originates proximal to the wrist from the superficial fascia and distally joins the abductor digiti minimi.
Figure 2 – Initial exposure for Guyon’s canal and carpal tunnel. Upon initial exposure, the palmaris brevis and a small portion of the aberrant abductor digiti minimi were identified
Figure 3 – Identification of the hypothenar muscles for orientation. By sweeping the ulnar nerve and vessels medially, the hypothenar muscles were identified medial to the marked hook of the hamate (purple). The deep motor branch of the ulnar nerve courses deep to this muscle. The palmar cutaneous branch of the ulnar nerve was identified and protected through this exposure.
Figure 4 – Identification of the tendinous leading-edge of the hypothenar muscles. The tendinous leading-edge of the hypothenar muscles can compress the deep motor branch of the ulnar nerve. This tendon was exposed by partially dividing the muscular tissue superficial to the tendon. The deep motor branch cannot be visualized until this tendon structure is divided.
Figure 5 – Decompressing the deep motor branch of the ulnar nerve. The deep motor branch of the ulnar nerve was decompressed by dividing the tendinous leading-edge of the hypothenars and hypothenar muscles.
Figure 6 – Decompressing the ulnar nerve through Guyon’s canal and exposing the aberrant muscle. The ulnar nerve was decompressed through Guyon’s canal. The aberrant abductor digiti minimi muscle was exposed to identify possible compression points and its innervation. The nerve to this aberrant muscle was visualized on its muscle belly.
Figure 7 – Partially releasing the aberrant abductor digiti minimi muscle origin. The aberrant abductor digiti minimi muscle had an origin proximal to the wrist from the superficial fascia and this muscle was partially released to relieve any tension on the ulnar nerve.
Figure 8 – Identification and management of the nerve to the aberrant abductor digiti minimi. (A) The ulnar nerve was followed proximally into the forearm and the nerve branch from the ulnar nerve to the aberrant muscle was identified. (B) The nerve branch to the aberrant muscle was clamped to cause an axonotmetic injury.
Figure 9 – Carpal tunnel release. Following surgical management of the aberrant muscle, the carpal tunnel was released due to carpal tunnel related symptoms. The transverse carpal ligament was identified and transected.
April 2011
Title: Restoration of Sensation Following Surgical Management of a Partial Median Nerve Laceration.
PNS ID: 110426-1, Published: 4/26/2011, Updated: 4/26/2011.
Author(s): Andrew Yee BS, Susan E. Mackinnon MD.
Division of Plastic and Reconstructive Surgery, Washington University School of Medicine, St. Louis, MO.
Figure 1 – Pre-operative Examination. A 27-year-old female patient presented to our institution five months following a partial median nerve injury to the left hand due to a glass laceration. The patient immediately reported dysesthesia in all digits following the injury, but within five minutes has resolved to just the thumb and index finger, which has persisted. Her pain was reported upon presenting at 3/10, but with significant impact on quality of life. Her sensation was reported at 5-6/10 in the affected thumb and index finger. Her moving and static two-point discrimination was reported for the thumb and index finger at 5 and 6 respectively. (A) Pre-operative surgical markings. (B) Magnification of the glass laceration injury.
Figure 2 – Exposure and Identification of the Median Nerve. (A) The palmar cutaneous branch of the ulnar nerve was identified distally and protected 3cm distal to the wrist crease during exposure. (B) To identify the median nerve through the injury zone and scar tissue, the median nerve (looped) was exposed proximally and followed distally. A median nerve neuroma was identified in the partially injured median nerve.
Figure 3 – Open Carpal Tunnel Release and Median Nerve Neurolysis. Due to the pre-operative findings and surgical findings, a conservative surgical management was elected rather than neuroma excision and nerve grafting. (A) An open carpal tunnel release was performed by decompressing the median nerve and transecting the transverse carpal ligament. The median nerve was also transversely and longitudinally neurolyzed. (B) The neuroma component of the median nerve was identified on the radial aspect of the median nerve. (C) Following the carpal tunnel release and median nerve neurolysis, a non-adhesion barrier was applied superficial to the median nerve to prevent adhesion to the superficial fascia during healing.
Figure 4 – Three Month Post-operative Examination. Three months post-operatively, the patient has nearly fully recovered her sensation. Moving and static two-point discrimination was between 2-4mm within the median nerve distribution, which included the injured index and thumb. The patient reported sensation for her thumb and index as 9/10 and 8/10 respectively. The patient also reported no pain and no impact on quality of life.
Figure 5 – Pre-operative and Post-operative Pain Evaluation. (A) Pre-operative pain evaluation described various pain descriptions and mild pain within the thumb and index finger. The patient reported 3/10 pain and major impact on quality of life. (B) Three months following the carpal tunnel release and median nerve neurolysis, the patient reported of no pain and restoration of sensation with no impact of quality life. Pain description and shady areas on the wrist are associated with wrist stiffness.
March 2011
Title: Long Term Follow-up on Tibial to Peroneal Nerve Transfer.
PNS ID: 110330-1, Published: 3/30/2011, Updated: 3/30/2011.
Author(s): Andrew Yee BS, Susan E. Mackinnon MD.
Division of Plastic and Reconstructive Surgery, Washington University School of Medicine, St. Louis, MO.
Figure 1 – Exposure of the Tibial Nerve on the Posterior Aspect of the Left Leg. The patient had a left foot drop due to a peroneal nerve injury following an athletic injury. A reconstruction option of tibial to peroneal nerve transfer was elected. The tibial nerve was exposed in the posterior aspect of the left leg. The exposure occurred between the medial and lateral heads of the gastrocnemius muscle. The soleus branch of the tibial nerve was identified as the donor nerve to reinnervate the tibialis anterior muscle.
Figure 2 – Peroneal Nerve Release at the Fibular Head and Exposure of the Recipient Peroneal Nerve. The peroneal nerve was released and exposed at the fibular head. The common peroneal nerve was identified by releasing the fibrous fascia of the peroneus longus. The target recipient nerves, the branch to the tibialis anterior and the branch to the peroneus longus and brevis, were isolated (not shown).
Figure 3 – Tibial to Peroneal Nerve Transfer. The soleus branch of the tibial nerve was transferred to the tibilias anterior branch of the deep peroneal nerve, seen superficial to the lateral head of the gastrocnemius muscle. In this case, the lateral gastrocnemius branch of the tibial nerve was additionally transferred to the peroneus longus and brevis branch of the peroneal nerve. A 10cm sural nerve graft was used to bridge the lateral gastrocnemius to peroneus nerve transfer.
Figure 4 – Post-operative Examination of the Recipient Tibialis Anterior and Peroneus Longus and Brevis. Five years following the tibial to peroneal nerve transfer of the left leg, tibialis anterior function significantly recovered. However, the recipient peroneus longus and brevis muscles (foot eversion) did not recover. (A,B) The patient was able to dorsiflex the left foot, with the tibialis anterior tendon visible. When compared to the normal right side, the range-of-motion of the left ankle was smaller. The left foot also demonstrated inversion due to the absent function of the peroneus eversion muscles. (C) The patient was able to dorsiflex the left foot against significant resistance.
Figure 5 – Post-operative Examination of Toe Extension. The extensor digitorum longus and brevis and the extensor hallucis longus were not targeted for reinnervation in the tibial to peroneal nerve transfer. (A) The patient was not able to extend the big toe against resistance (as expected). (B) The patient was not able to extend the remaining toes against resistance (as expected).
Figure 6 – Post-operative Examination of the Donor Deficit. The tibial nerve branch to the soleus was used as a donor nerve to reinnervate the tibialis anterior. The tibial nerve branch to the lateral gastrocnemius was used as a donor nerve to reinnervate the peroneus longus and brevis. The patient did not exhibit a function-limiting donor deficit. (A,B,C,D) The patient was able to plantarflex the left foot against gravity without difficulty. Wasting of the lateral head of the gastrocnemius in the left leg can be seen. (E) The patient was able to plantarflex the left foot against resistance.
Video 1 – Intra-operative Ulnar Nerve Stimulation Six Days Following an Ulnar Nerve Transection. Under tourniquet, the ulnar nerve was decompressed through Guyon’s canal, specifically releasing the deep motor branch, and the dissection of the ulnar nerve was carried proximally into the distal forearm. The sensory/motor topography mapping of the ulnar nerve was then completed to identify the dorsal cutaneous branch and the adjacent motor component of the ulnar nerve. The cleavage plane between the motor and sensory component of the ulnar nerve was then opened slightly for a distance of less than a centimeter. Even though the patient was dis days following the proximal transection of the ulnar nerve above the elbow, our institution elected to stimulate the ulnar nerve motor fascicular group to determine whether or not there was an indication of a Martin-Gruber anastomosis. Upon motor group stimulation in the video, there was some contraction of the ulnar intrinsic muscles. This case was an ideal situation for a reverse end-to-side (RETS) anterior interosseous to ulnar motor nerve transfer. If the classical direct end-to-end anterior interosseous to ulnar motor nerve transfer was performed, then the Martin-Gruber component from the median to ulnar nerve would have been sacrificed. In this situation, the Martin-Gruber anastomosis was an advantage and the RETS procedure allowed for the augmentation of this anastomosis.
Title: Reconstruction of Iatrogenic Ulnar Nerve Injury Following an Ulnar Collateral Ligament Reconstruction.
PNS ID: 110325-2, Published: 3/25/2011, Updated: 3/25/2011.
Author(s): Andrew Yee BS, Simone W. Glaus MD, Susan E. Mackinnon MD.
Division of Plastic and Reconstructive Surgery, Washington University School of Medicine, St. Louis, MO.
Abstract: A 19-year-old right hand dominant athlete underwent a right ulnar collateral ligament reconstruction (Tommy John surgery). This was complicated by complete oblique transection of the ulnar nerve approximately 7 cm proximal to the elbow. The ulnar nerve was immediately primarily repaired and subcutaneously transposed. Five days following the ulnar nerve injury and reconstruction, the patient presented to our institution for consultation. The right arm was casted to support the collateral ligament repair. This prohibited extensive physical examination including pinch and grip testing, but a complete absence of sensation in the ulnar distribution was noted. Additionally, the patient reported significant neuropathic pain in the ulnar nerve distribution.
Regarding a surgical plan, options included an end-to-end (ETE) versus a reverse end-to-side (RETS) anterior interosseous to ulnar motor nerve transfer. Taking into consideration the immediate and excellent primary nerve repair and the relative youth and good regenerative capability of the patient, both institutions decided that there was a possibility for ulnar nerve regeneration and ulnar intrinsic recovery if the ulnar intrinsic muscles could be supported with a RETS nerve transfer. Our experimental work in a rodent model has shown that a RETS nerve transfer of a given nerve can provide the same number of nerve fibers as an end-to-end transfer of the same nerve (in press). When an acceptable donor motor nerve such as the distal AIN is available, a RETS nerve transfer, in combination with primary repair of the injured nerve proximally, may assist in augmenting the total number of nerve fibers reaching the distal muscle. Additionally, distal RETS nerve transfer may provide more expedient reinnervation of the motor end plates, babysitting; end plates through collateral sprouting until native motor axons have regenerated. This is critical in light of the time constraints for good motor recovery (in our clinical experience, little to no additional muscle functional recovery is seen after 12-18 months of denervation). With regards to sensory recovery, because sensory recovery is not subject to the same time limitations as motor recovery, both institutions determined not to proceed with any sensory nerve transfers. There is a reasonable chance that the patient will recover some sensation in the ring and small fingers from the initial primary ulnar nerve repair. If there is persistent numbness in these fingers over time, a third webspace to ulnar sensory nerve transfer could then be performed.
The actual surgical management of this case included a RETS anterior interosseous to ulnar motor nerve transfer and a profundus tenodesis. Due to the recent presentation of this case, the results following this reconstruction are pending long term follow-up.
Figure 1 – Pre-operative Examination Following an Iatrogenic Ulnar Nerve Injury after an Ulnar Collateral Ligament Reconstruction. The patient previously had an ulnar collateral ligament reconstruction (Tommy John Surgery) at which a complication occurred and the ulnar nerve was completely transected. Immediately following, the ulnar nerve was primarily repaired and subcutaneously transposed. The patient presented to our institution with complete loss of ulnar nerve function and reports of 10/10 pain. (A) Reconstruction of the complete ulnar nerve transection proximal to the elbow. The right arm was prepped/drapped and proposed incision noted for a Guyon’s canal release, reverse end-to-side anterior interosseous to ulnar motor nerve transfer, and a profundus tenodesis. (B) The small step incisions, where the palmaris tendon was harvested for the Tommy John Surgery six day prior, are noted. (C) Previous surgical incision from the ulnar nerve repair and transposition.
Figure 2 – Flexor Digitorum Profundus Tenodesis. The flexor digitorum profundus (FDP) tenodesis was performed between the ring and small finger FDP tendons and the long finger FDP tendon. The patient had completely independent FDP tendon to the index finger, which was not included in the profundus tenodesis. Three Ethibond sutures are noted. A bit of extra tension was placed on the FDP tendons to the ring and small finger to allow the normal profundus function to the long finger to be transmitted. The profundus tenodesis improves finger flexion immediately following reconstruction.
Figure 3 – Reverse End-to-side Anterior Interosseous to Ulnar Motor Nerve Transfer. Due to the proximal ulnar nerve injury, the reverse end-to-side (RETS) anterior interosseous to ulnar motor nerve transfer was elected. (A) The ulnar nerve was identified in the forearm. Distally, the ulnar nerve was decompressed through Guyon’s canal and the deep motor branch was identified and decompressed. (B) The end of the anterior interosseous nerve was transferred in a RETS fashion to the side of the motor component of the ulnar nerve via an epineurial/perineurial window. The motor component was identified to be between the dorsal cutaneous branch of the ulnar nerve and the sensory component of the ulnar nerve. Note that it is important to identify the dorsal cutaneous branch of the ulnar nerve (DCU) proximally in order to confirm that the motor fascicular group is sandwiched between the DCU and the ulnar sensory component. Also, the identification of the deep motor branch and Guyon’s canal dissection allowed for us to follow the motor component proximally to confirm the corrent proximal motor and sensory topography. In this specific case, a Martin-Gruber anastomosis was present, the stimulation of the ulnar nerve motor component revealed some (but not normal) intrinsic muscle response.
Figure 4 – Inspection of the Previous Ulnar Nerve Repair and the Submuscular Transposition. Immediately following the ulnar nerve transection, the ulnar nerve was primarily repaired and subcutaneously transposed by an outside institution. The repair and transposition was “checked.” There was no tension along the course of the ulnar nerve and no kinking of the ulnar nerve distally. The repair site was noted below the blue background and appeared excellent.
Figure 5 – Magnification of the Previous Ulnar Nerve Repair. The ulnar nerve was transected at the above-the-elbow level during an ulnar collateral ligament reconstruction. Immediately following the transection, the ulnar nerve was primarily repaired by the outside institution. The ulnar nerve repair was inspected by our institution and appeared excellent.
Video 1 – Intra-operative Ulnar Nerve Stimulation Six Days Following an Ulnar Nerve Transection. Under tourniquet, the ulnar nerve was decompressed through Guyon’s canal, specifically releasing the deep motor branch, and the dissection of the ulnar nerve was carried proximally into the distal forearm. The sensory/motor topography mapping of the ulnar nerve was then completed to identify the dorsal cutaneous branch and the adjacent motor component of the ulnar nerve. The cleavage plane between the motor and sensory component of the ulnar nerve was then opened slightly for a distance of less than a centimeter. Even though the patient was dis days following the proximal transection of the ulnar nerve above the elbow, our institution elected to stimulate the ulnar nerve motor fascicular group to determine whether or not there was an indication of a Martin-Gruber anastomosis. Upon motor group stimulation in the video, there was some contraction of the ulnar intrinsic muscles. This case was an ideal situation for a reverse end-to-side (RETS) anterior interosseous to ulnar motor nerve transfer. If the classical direct end-to-end anterior interosseous to ulnar motor nerve transfer was performed, then the Martin-Gruber component from the median to ulnar nerve would have been sacrificed. In this situation, the Martin-Gruber anastomosis was an advantage and the RETS procedure allowed for the augmentation of this anastomosis.
Title: Follow-up After Reconstruction of Iatrogenic Accessory Nerve Palsy from Lymph Node Biopsy.
PNS ID: 110325-1, Published: 3/25/2011, Updated: 3/25/2011.
Author(s): Andrew Yee BS, Susan E. Mackinnon MD.
Division of Plastic and Reconstructive Surgery, Washington University School of Medicine, St. Louis, MO.
Abstract: This 35-year-old right hand dominant female presented to our institution six months after a left neck lymph node biopsy at an outside institution. Immediately after the biopsy, the patient lost the ability to abduct and partially flex her left shoulder. Electrodiagnostic studies demonstrated no motor unit potentials in the middle and lower trapezius muscles. Upon examination, a small slip of the upper trapezius muscle was functioning, but otherwise no trapezius function was noted. The patient reported severe pain in the general left shoulder and neck region. At the time of reconstructive surgery, the accessory nerve was found to be completely transected in the region of the biopsy. The neural scar tissue was excised until a normal fascicular nerve pattern was seen proximally and distally. A 4cm gap in the accessory nerve was present after removal of the scar tissue. The medial antebrachial cutaneous (MABC) nerve was harvested from the left arm for graft material, and a 5.5cm MABC nerve graft was used to reconstruct the accessory nerve. To restore rudimentary sensation to the MABC nerve distribution, the distal end of the transected MABC was transferred to the sensory component of the median nerve in an end-to-side fashion. By one year post-operatively, the patient recovered full range of motion for shoulder abduction and shoulder flexion, but exhibited an over-developed left upper trapezius muscle. No sensory donor site deficit was found within the MABC distribution one year post-operatively. This case describes a successful outcome in a reconstruction of an iatrogenic accessory nerve palsy with a 5.5cm MABC nerve graft. The patient was able to recovery accessory nerve function with no residual MABC nerve donor deficit.
Figure 1 – Pre-operative Examination Following Lymph Node Biopsy. The patient presented with a complete spinal accessory nerve injury follwing a left neck lymph node biopsy. The patient had much more difficulty with shoulder abduction than with shoulder forward flexion. Shoulder forward flexion is controlled primarily by the long thoracic nerve, but shoulder abduction is controlled primarily by accessory nerve innervation to the middle and lower trapezius muscles. Some winging of the left scapula is also noted. An important component of the pre-operative examination of patients with complete main accessory nerve injury is to understand the functionality of the upper trapezius muscle slip. A functioning upper trapezius muscle slip may give the examiner “false hope” that the accessory nerve has not been injured, when, in fact, this muscle slip is innervated by an accessory branch of the accessory nerve. Therefore, upper trapezius muscle slip function is usually present even when the main accessory nerve is completely transected. (A) The patient was only able to forward flex the left shoulder to 90°. (B) The patient was only able to abduct the left shoulder to approximately 45°.
Figure 1 – Pre-operative Examination Following Lymph Node Biopsy. The patient presented with a complete spinal accessory nerve injury follwing a left neck lymph node biopsy. The patient had much more difficulty with shoulder abduction than with shoulder forward flexion. Shoulder forward flexion is controlled primarily by the long thoracic nerve, but shoulder abduction is controlled primarily by accessory nerve innervation to the middle and lower trapezius muscles. Some winging of the left scapula is also noted. An important component of the pre-operative examination of patients with complete main accessory nerve injury is to understand the functionality of the upper trapezius muscle slip. A functioning upper trapezius muscle slip may give the examiner “false hope” that the accessory nerve has not been injured, when, in fact, this muscle slip is innervated by an accessory branch of the accessory nerve. Therefore, upper trapezius muscle slip function is usually present even when the main accessory nerve is completely transected. (A) The patient was only able to forward flex the left shoulder to 90°. (B) The patient was only able to abduct the left shoulder to approximately 45°.
Figure 2 – Spinal Accessory Nerve Repair with Medial Antebrachial Cutaneous Nerve Graft. (A) After resection back to healthy nerve, the left spinal accessory nerve had a 4cm gap; this gap was repaired in a tension-free manner with a 5.5cm medial antebrachial cutaneous nerve (MABC) graft. The incision scar is noted. (B) The MABC graft was harvested from the medial aspect of the left arm. To restore rudimentary sensation to the MABC distribution, the distal end of the MABC was transferred to the sensory component of the median nerve in an end-to-side fashion. One year following the procedure, the patient reported no sensory deficient in the MABC distribution.
Figure 3 – Post-operative Recovery Following the Spinal Accessory Nerve Repair. Upon examination one year following the spinal accessory nerve repair, the patient had recovered spinal accessory nerve function. (A,B) The patient recovered full range-of-motion of shoulder abduction. (C,D) The patient recovered full range-of-motion of shoulder forward flexion. (E) The patient exhibited an over-developed upper trapezius muscle. This was previously a slip of the upper trapezius muscle that was innervated by an accessory branch of the accessory nerve, rather than by the transected main trunk of the accessory nerve. This small slip of the upper trapezius functioned normally throughout the patient’s entire reconstructive course. The patient complained of some discomfort and tightness in this muscle slip post-operatively. Our recommended treatment for the discomfort and tightness was Botox injection. This temporarily weakens the muscle slip, giving an opportunity for the patient to stretch out the tight muscle.
Figure 4 – Pre-operative and Post-operative Pain Evaluation. (A) The patient reported significant pain in the left shoulder and neck region immediately following the left neck lymph node biopsy. (B) One year following the spinal accessory reconstruction with a nerve graft, the majority of the pain has resolved. The patient reported some residual pain isolated to a slip of the upper trapezius. This muscle slip was functional throughout the patient’s nerve injury and reconstruction and was found to be over-developed.
Video 1 – Pre-operative Examination Following Lymph Node Biopsy. Patient presented with a left spinal accessory nerve injury to our institution following a left neck lymph node biopsy. Upon examination, the patient was only able to forward flex the left shoulder to 90°. In addition, scapular winging is evident on the left shoulder. The patient was only able to abduct the left shoulder to approximately 45°.
Video 2 – Post-operative Recovery Following the Spinal Accessory Nerve Repair. Upon examination one year following the spinal accessory nerve repair, the patient recovered spinal accessory nerve function. The patient recovered full range-of-motion shoulder abduction. The patient also recovered full range-of-motion shoulder forward flexion. This is a typical result for this type of reconstruction. The results are excellent on this reconstruction possibly due to the accessory nerve being a true motor reconstruction without any sensory component. Even though there exists a long distance to reinnervate the middle and lower trapezius, our experience has seen this type of outstanding recovery following reconstruction of a complete accessory nerve injury with a short nerve graft.
Title: Reconstruction of a Failed Nerve Wrap for an Ulnar Nerve Laceration.
PNS ID: 110323-1, Published: 3/23/2011, Updated: 4/22/2011.
Author(s): Simone W. Glaus MD, Andrew Yee BS, Susan E. Mackinnon MD.
Division of Plastic and Reconstructive Surgery, Washington University School of Medicine, St. Louis, MO.
Abstract: A 53-year-old right-hand-dominant woman lacerated her left ulnar nerve on broken glass five months before she presented to our institution. Her ulnar nerve was reconstructed by an outside institution with a nerve wrap 7mm in diameter and 2cm in length. Upon examination at our institution, she had no recovery of ulnar nerve function. An ultrasound showed an apparent 7mm gap in the ulnar nerve. The patient’s main complaint was severe pain in the ulnar nerve distribution. A strong Tinel’s sign was present at the level of the nerve repair with no advancement. She also had significant hypersensitivity in the ulnar nerve distribution. An exploration and an ulnar nerve repair with a medial antebrachial cutaneous nerve graft were elected. At the time of the surgery, it was noted that the deep motor branch had not been decompressed and was not involved in the initial nerve reconstruction. Two months post-operatively, there was an advancing Tinel’s sign and resolution of pain. The long-term results following this reconstruction are pending due to the recent presentation of this case.
Figure 1 – Pre-op Examination and Previous Surgical Incision. The patient lacerated her ulnar nerve on glass. The ulnar nerve was repaired primary at an outside institution and reinforced with a 7mm diameter and 2cm length nerve wrap. The patient presented to our institution five months following the injury. The patient reported severe pain in the volar aspect of the ulnar nerve distribution and had no intrinsic ulnar nerve motor function. The previous incision scar has been noted in the image (dotted lines).
Figure 2 – Exposure of the Ulnar Nerve. Upon exposure of the ulnar nerve, the previous nerve repair with the nerve wrap was visualized. Two digital cutaneous sensory branches of the ulnar nerve were identified and protected. The sensory component of the ulnar nerve was incorporated in the nerve repair. The deep motor branch of the ulnar nerve was not visualized when the ulnar nerve was isolated.
Figure 3 – Identifying the Deep Motor Branch of the Ulnar Nerve. (A) To locate the deep motor branch of the ulnar nerve, which was not immediately apparent, the dissection approached the tendinous leading edge of the hypothenar muscles, found ulnar to the hook of the hamate (purple). (B) The tendinous leading edge of the hypothenar muscles was released to reveal the deep motor branch of the ulnar nerve. (C) Upon further exposure, it was found that the deep motor branch had not been included in the previous nerve repair.
Figure 4 – Isolating the Motor and Sensory Components of the Ulnar Nerve Proximally. (A) The ulnar nerve was exposed proximally until the dorsal cutaneous branch was identified as a surgical landmark. (B) The motor component of the ulnar nerve is known to lie immediately radial to the dorsal cutaneous branch. Neurolysis of the ulnar nerve revealed the motor component (purple) and the sensory component, which is located radial to the motor component. (C) Once the topographical ulnar nerve anatomy was confirmed, neurolysis preceded distally into the nerve repair to identify the respective motor and sensory components of the ulnar nerve.
Figure 5 – Histological Assessment of the Failed Ulnar Nerve Wrap. The zone of injury was identified and the injured segment was resected until healthy fascicles were seen. (A) The distal segment of the nerve wrap revealed scarce, small unmyelinated nerve fibers (sensory fibers). (B) The middle segment revealed nerve fibers sprouting in various directions, giving an uneven appearance to the section. In addition, dense scar formation was seen. (C) The proximal segment revealed healthy nerve fibers. (D) Histological assessment of the unrepaired deep motor branch of the ulnar nerve revealed no nerve fibers. A,B,C – 250x magnification; D – 400x magnification.
Figure 6 – Magnification of the Resected Nerve Wrap Repair. Scar tissue was observed within the nerve wrap repair after resection. Note the glassy scar appearance of the mid-wrap as compared to the normal fascicular appearance in the proximal and distal aspects (arrows). Suture material from the original primary repair was observed.
Figure 7 – Histological Assessment of the Proximal Nerve Wrap Repair. Histological assessment of the proximal nerve wrap repair revealed normal nerve fibers, but degenerative nerve fibers and cylindrical hyaline bodies (Renaut bodies) were also observed. Renaut bodies suggest compression of the proximal nerve by the wrap. (A) Degenerative nerve fibers were observed along with normal nerve fibers in this fascicular unit. (B) Renault bodies were observed in this fascicular unit. (C) Magnification of the degenerative nerve fibers. (D) Magnification of the Renault bodies. A,B – 100x magnification; C,D – 250x magnification.
Figure 8 – Medial Antebrachial Cutaneous Nerve Harvest for Graft Material. (A) The anterior branch of the medial antebrachial cutaneous nerve (MABC) was exposed superior to the basilic vein and isolated in the medial aspect of the arm. The posterior branch of the MABC nerve was also identified inferior to the basilic vein. (B) The anterior branch of the MABC nerve was harvested. (C) To restore rudimentary sensation in the MABC anterior branch distribution, the distal end of the MABC anterior branch was transferred to the MABC posterior branch in an end-to-side fashion. Following the prioritized ulnar nerve reconstruction with the harvested MABC graft, the unused MABC graft material was used to bridge the end-to-side nerve transfer for a tension-free repair.
Figure 9 – Reconstruction of the Failed Ulnar Nerve Wrap with MABC Grafts. (A) The nerve wrap and the zone of injury were resected to reveal the distal deep motor branch and the sensory branches of the ulnar nerve. Proximally, the sensory component and the motor component were topographically mapped. (B) The motor component of the ulnar nerve was grafted to the deep motor branch with one medial antebrachial nerve (MABC) graft. The sensory component of the ulnar nerve was grafted to the two sensory branches with two MABC grafts. Three 6cm MABC nerve grafts were used in total.
History
A 53 year-old left-hand dominant female sustained a laceration to her volar right wrist at the level of Guyon’s canal when she accidentally fell onto broken glass. The wound was sutured at the time of injury, but the patient had persistent numbness in the ulnar nerve distribution and complained of inability to spread her fingers. On exam, the patient was found to have decreased ulnar light touch sensation and weakness of the interosseous muscles. Approximately 2 weeks after her initial injury, the patient was taken to the OR for exploration. The ulnar nerve was found to be completely lacerated, with approximately 1 cm of gaping between the nerve ends. The nerve ends were trimmed and re-approximated with the wrist in flexion. A primary epineurial repair was performed, followed by wrapping of the nerve with a 7 mm diameter, 2 cm long collagen nerve wrap. The patient was maintained in a short arm cast with the wrist in slight volar flexion for 3 weeks postoperatively. The patient did not recover substantial motor or sensory function by two and a half months postoperatively and underwent electrical studies and ultrasound. EMG showed no conduction through the ulnar nerve at the level of the wrist and 2+ fibrillations in the first dorsal interosseous and abductor digiti minimi muscles. Ultrasound revealed a 7 mm gap in the repair site. The patient was seen in our clinic approximately 5 months after her injury.
Physical Examination
Intrinsic muscle atrophy was present in the right hand. Sensory exam revealed moving and static two-point discrimination of 3-4 mm in the median nerve distribution and 6 mm in the ulnar distribution. Motor exam on the right showed no ulnar intrinsic function, a pinch strength of 4 lb, and a grip strength of 34 lb. Pinch and grip on the left were 14 lb and 65 lb, respectively. Tinel’s sign was present at the site of the nerve repair, and the patient had hypersensitivity in the ulnar nerve distribution of her hand. Normal extrinsic ulnar motor function was present.
Diagnostic Testing
No further diagnostic testing was indicated. Please see initial history for EMG and ultrasound findings obtained prior to referral.
Management
Preoperative: None.
Surgical: Re-exploration of the right ulnar nerve was performed via extension of the patient’s previous incision proximally and distally. The prior reconstruction and nerve wrap were identified. The proximal ulnar nerve entered the wrap, and the sensory component of the ulnar nerve exited the wrap. However, the deep motor branch had not been explored and had not been included in the reconstruction. Guyon’s canal was completely released. The deep motor branch was identified. Proximally, the ulnar nerve was traced until the dorsal cutaneous branch (DCB) was found to be intact. This allowed for topographical mapping of the ulnar nerve (at the level of the DCB, the motor fascicular group lies sandwiched between the DCB and the sensory fascicular group). When the nerve wrap and scar tissue were excised so that healthy fascicles were seen, a gap of approximately 6 cm remained. Through a separate incision, the medial antebrachial cutaneous nerve (MABC) was harvested to serve as an autograft. 3 cables of MABC total, each 6 cm in length, were used to graft the ulnar nerve, taking care to match the motor fascicular group to the deep motor branch (one cable) and the sensory fascicular group to the sensory component distally (two cables). The distal end of the (anterior) branch of the MABC, which had been harvested, was reconstructed to the posterior cutaneous branch of the MABC in and end-to-side fashion. A Marcaine pain pump was placed intraoperatively at the time of wound closure.
Post-operative: The pain pump was removed 3 days postoperatively. The patient was instructed to rest her wrist for an additional 10 days prior to starting active range of motion. She was provided with a neutral wrist splint to wear at night, given her tendency to sleep with the wrist hyperflexed.
Patient Outcomes
At 7 weeks postoperatively, the patient’s pinch and grip on the right were 6 lb and 30 lb, compared to 14 lb and 55 lb on the left. Tinel’s sign had advanced by approximately 1 inch. Physical therapy is ongoing and longer term results are pending. Given the typical nerve regeneration rate of one mm per day, or one inch per month, a longer period of follow-up is required to observe ulnar nerve recovery.
Discussion
For any laceration of the distal ulnar nerve, correct alignment of the sensory and motor topography is essential to optimizing recovery. By tracing out the deep motor branch to identify the distal continuation of the motor fascicular group, and by finding the dorsal cutaneous branch proximally to identify the level at which the motor fascicular group is sandwiched between the dorsal cutaneous branch and the sensory fascicular group, the topography can be appropriately mapped prior to nerve repair. Additionally, depending on the level of the injury, this will also ensure that all components are adequately reconstructed (i.e., tracing out the deep motor branch in this case would have revealed that it had been severed).
References
Polatsch DB, Melone CP Jr, Beldner S, Incorvaia A. Ulnar nerve anatomy. Hand Clin. 2007 Aug; 23(3): 283-9.
Pfaeffle HJ, Waitayawinyu T, Trumble TE. Ulnar nerve laceration and repair. Hand Clin. 2007 Aug; 23(3): 291-9.
Brown JM, Yee A, Mackinnon SE. Distal median to ulnar nerve transfers to restore ulnar motor and sensory function within the hand: technical nuances. Neurosurgery. 2009 Nov; 65(5): 966-77. (Description of topographical mapping of the ulnar nerve)
Title: Reconstruction of a Failed Nerve Wrap for an Ulnar Nerve Neuroma Resection.
PNS ID: 110318-1, Published: 3/18/2011, Updated: 4/6/2011.
Author(s): Simone W. Glaus MD, Andrew Yee BS, Susan E. Mackinnon MD.
Division of Plastic and Reconstructive Surgery, Washington University School of Medicine, St. Louis, MO.
Abstract: A 55-year-old right-hand dominant male physician had a painful granular cell tumor partially removed from his ulnar nerve. The excised portion of the nerve was reconstructed with a nerve wrap. It was thought at the time of surgery that the nerve biopsy originated from the sensory component of the ulnar nerve; however, post-operatively the patient was found to have normal sensation and complete loss of ulnar intrinsic motor function. Upon presenting to our institution, the patient had complete ulnar intrinsic atrophy of the right hand with a positive Froment’s sign, ring and small finger clawing, and inability to abduct or adduct the fingers. The patient elected to have the surgical site re-explored with a plan to use an autologous motor nerve graft to reconstruct the motor component of the ulnar nerve. At surgery, the ulnar nerve was decompressed through Guyon’s canal. The normal functioning sensory component of the ulnar nerve was protected while the area of nerve injury and previous nerve wrap reconstruction were excised. The nerve gap was reconstructed with a 5.5 cm graft using the obturator motor nerve to the gracilis muscle as a nerve graft. The results following this reconstruction are pending long term follow-up due to the recent presentation of this case.
Figure 1 – Pre-op Examination Following Ulnar Nerve Wrap for an Ulnar Nerve Neuroma Resection. The patient presented with complete loss of ulnar intrinsic motor function following ulnar nerve biopsy and failed nerve wrap reconstruction. (A) Ulnar intrinsic atrophy and a positive froment’s sign are evident in the right hand. (B) Wartenburg’s sign (unopposed small finger abduction) and clawing is also noted.
Figure 2 – Previous Incision Scar. The incision from the original surgery is noted proximal to the wrist.
Figure 3 – Guyon’s Canal Release with Decompression of Deep Motor Branch. The revision surgery begins with exposure of the ulnar nerve through Guyon’s canal and decompression of the deep motor branch. This will allow regeneration to occur unimpeded by this potential entrapment point. Identification of the deep motor branch also allows for clear topographical mapping of the ulnar nerve motor and sensory components distal to the area of the previous surgery.
Figure 4 – Exposure of Ulnar Nerve Wrap Repair. (A) After further exposure, the motor component of the ulnar nerve was looped with a blue vessel loop and the sensory component looped with a white vessel loop. Proximally, the sensory component of the ulnar nerve was protected with a white vessel loop. The scarred motor component is seen ulnar to the sensory component. The dorsal cutaneous branch of the ulnar nerve is barely visible at the bottom right of the picture (white vessel loop). The deep motor branch distally and the dorsal cutaneous branch proximally serves as anatomical landmarks to help insure the proper identification of the ulnar nerve motor and sensory topography. (B) The ulnar nerve was twisted to identify the area of injury and the previously reconstructed motor component (blue vessel loops), while the sensory component (white vessel loops) was protected. (C) Further neurolysis identified the prior area of injury and nerve wrap reconstruction. (D) The proper orientation and course of the ulnar nerve is depicted in this image. In the hand, the motor component of the ulnar nerve is deep and radial to the sensory component as it curves around the hook of the hamate. At the level of the distal forearm, the motor component switches from the radial position to an ulnar position with respect to the main sensory component.
Figure 5 – Nerve Wrap Resection and Histology. (A) The area of injury and the previous nerve wrap reconstruction were identified and resected. (B) Dense scar tissue was observed within the resected injured nerve. (C) Histological results for the proximal and distal ends of the resected injured nerve are pending.
Figure 6 – Obturator Nerve Graft Harvest. The gracilis branch of the obturator nerve was harvested as a motor autograft. 10 cm of graft length was harvested. 5.5 cm was ultimately used to bridge the gap in the motor component of the ulnar nerve.
Figure 7 – Reconstruction of Deep Motor Branch of Ulnar Nerve with an Obturator Nerve Graft. (A) A nerve gap distance of 4.5 cm was measured. (B) The gracilis branch of the obturator nerve was harvested as a motor autograft. (C) 5.5 cm of the motor autograft was used to reconstruct the motor component of the ulnar nerve. The obturator nerve graft is seen in place with redundancy to allow full range of movement in the hand with no tension on the nerve graft. The sensory component is protected and behind the blue backgrounds.
History
A 54 year-old right-hand dominant male developed extreme sensitivity over the course of months at the right ulnar nerve proximal to wrist crease. There was no history of trauma, and physical examination was normal except for a positive Tinel’s and pain over the area of complaint. EMG was normal. MRI showed a small area of fusiform swelling of the ulnar nerve, most consistent with a benign mass. The patient underwent exploration and was found to have fusiform swelling within what was identified as the sensory fascicular group, which was stuck to the motor fascicular group. The sensory and motor fascicular groups were separated, and multiple biopsies were taken of the lesion. Intraoperative stimulation revealed the motor component to be intact. A nerve conduit was applied as a wrap to the sensory component to keep it separate from the motor fascicular group. Immediately postoperatively, the patient demonstrated complete ulnar intrinsic motor palsy with normal ulnar sensory function. This was felt to likely be a first or second degree injury from dissection of the components prior to biopsy. An ultrasound was obtained approximately 2 weeks postoperatively which showed no evidence of constriction, laceration, or defect. An EMG was obtained approximately 2 months postoperatively which showed evidence of a severe ulnar nerve injury at the distal wrist. The patient was referred to our clinic at that time. Of note, the patient’s profession required very fine and precise motor control of his fingers, making this palsy devastating to his career.
Physical Examination
Complete intrinsic muscle atrophy and clawing of the ring and small fingers were present in the right hand. Sensory exam revealed moving and static two-point discrimination of 5 mm in the median and ulnar nerve distributions bilaterally. Motor exam showed a positive Froment’s sign, an inability to cross the fingers, a pinch strength of 3 lb, and a grip strength of 70 lb. Pinch and grip on the left were 18 lb and 80 lb, respectively. Tinel’s sign was present just proximal to the wrist crease, at the site of the patient’s scar.
Diagnostic Testing
Repeat EMG: Right ulnar motor nerve conduction study from the abductor digiti minimi (ADM) showed normal onset latency, normal conduction velocity, and a very small distal compound muscle action potential (CMAP) amplitude. Right ulnar motor nerve conduction study from the first dorsal interosseous (FDI) showed no CMAP. 2+ to 3+ fibrillations and positive sharp waves were present in the right ADM and FDI. Severely reduced recruitment of motor unit potentials (MUPs) was noted at the ADM, and no voluntary MUPs were present at the FDI. Right ulnar sensory testing was normal.
Management
Preoperative: The preoperative plan was to perform a re-exploration with decompression of the ulnar nerve through Guyon’s canal, removal of the tumor, and autologous nerve grafting of affected sensory and motor components. Repeat EMG testing was performed prior to re-exploration.
Surgical: Re-exploration of the right ulnar nerve was performed via the patient’s previous incision, which was extended proximally and distally. The ulnar nerve was identified in Guyon’s canal and was decompressed through Guyon’s canal and at the deep motor branch distally. Intraoperative stimulation of the deep motor branch produced no motor function. The deep motor branch of the ulnar nerve was then traced proximally to identify the sensory and motor topography. Additionally, the dorsal cutaneous branch of the ulnar nerve was identified in the proximal incision and traced distally to identify sensory and motor topography. Carefully proceeding into the area of previous surgery, the nerve wrap was identified around the motor component of the ulnar nerve. This was neurolysed away from the sensory component and resected. Meanwhile, a second surgeon harvested the gracilis branch of the left obturator nerve to serve as an autologous graft of motor origin. A motor donor nerve was chosen for its potential benefit in regeneration over a sensory nerve graft, given the patient’s professional need to recover absolutely as much function as possible. After complete removal of the prior conduit wrap reconstruction and the tumor in its entirety, a defect of 5.5 cm remained. This gap was grafted using the harvest gracilis branch of the obturator nerve, which provided a good size match and tension-free repair. The proximal graft repair site was at a level 6 cm proximal to the wrist crease.
Post-operative: The patient’s pathology revealed a granular cell tumor, which was completely excised.
Patient Outcomes
The patient experienced no complications following surgery. One month postoperatively, the patient’s sensory exam was normal (unchanged from preoperative exam). Motor exam showed a pinch strength of 8 lb, and a grip strength of 58 lb, compared to 18 lb and 70 lb on the left. Further follow-up is pending. Given the typical nerve regeneration rate of one mm per day, or one inch per month, a longer period of follow-up is required to observe ulnar nerve recovery.
Discussion
Reliable topographical mapping of the ulnar nerve can be performed in two ways—using either the dorsal cutaneous branch or the deep motor branch as a landmark:
(1) Distal to the takeoff of the dorsal cutaneous branch (DCU), the sensory component of the ulnar nerve makes up about 60% of the nerve cross-sectional area, and the motor component that continues as the deep motor branch makes up the remaining 40%. Proximal to the takeoff of the DCU, the motor fascicular group is “sandwiched” between the DCU medially (i.e., ulnarly) and the main sensory component of the ulnar nerve laterally (radially). The DCU branches off from the main ulnar nerve about 10 cm above the wrist crease. As it travels distally, the motor component turns into the deep motor branch of the ulnar nerve (DMB) and moves from lying medial to the sensory portion of the ulnar nerve, to travelling under the sensory component as it turns around the hook of the hamate, where it finally assumes a position lateral to the sensory component. There is an intraneural cleavage plane between the motor and sensory groups, as well as between the main ulnar nerve and the DCU, that is easily discernible using micro-pickups. Tapping across the surface of the nerve, micro-pickups will “fall” into the intraneural cleavage plane. Often, there is also a streak of fatty tissue or a micro-vessel that also delineates this cleavage plane.
(2) Alternatively, the motor and sensory components can be clearly delineated by tracing the DMB proximally to identify the motor fascicular group. In the forearm, at or proximal to the level of the wrist, the larger sensory component of the ulnar nerve will lie most laterally (i.e., most radially) compared to the motor component, and above 10 cm proximal to wrist level, there will also be a smaller fascicular group present on the most medial (ulnar) aspect that is the DCU.
References
Polatsch DB, Melone CP Jr, Beldner S, Incorvaia A. Ulnar nerve anatomy. Hand Clin. 2007 Aug; 23(3): 283-9.
Brown JM, Yee A, Mackinnon SE. Distal median to ulnar nerve transfers to restore ulnar motor and sensory function within the hand: technical nuances. Neurosurgery. 2009 Nov; 65(5): 966-77. (Description of topographical mapping of the ulnar nerve)
Magill CK, Moore AM, Mackinnon SE. Same modality nerve reconstruction for accessory nerve injuries. Otolaryngol Head Neck Surg. 2008 Dec; 139(6): 854-6. (Use of a motor autograft to repair a motor nerve defect)
Title: Reconstruction of a Failed 1cm Ulnar Nerve Conduit.
PNS ID: 110316-1, Published: 3/16/2011, Updated: 4/5/2011.
Author(s): Simone W. Glaus MD, Andrew Yee BS, Susan E. Mackinnon MD.
Division of Plastic and Reconstructive Surgery, Washington University School of Medicine, St. Louis, MO.
Abstract: This 20-year-old right hand dominant woman lacerated her ulnar nerve when she accidentally pushed her hand through a pane of glass. Two weeks following the injury, her right ulnar nerve was reconstructed at an outside institution using a 4mm diameter, 1cm long collagen conduit. The small finger FDS tendon, flexor carpi ulnaris tendon, and ulnar artery were also repaired. Upon presenting to our institution six months following her injury, the patient had no ulnar nerve function and a non-advancing, painful Tinel’s sign at the mid-portion of the surgical scar. She elected to undergo re-exploration and reconstruction of the ulnar nerve. The ulnar nerve was decompressed through Guyon’s canal. The area of injury and previous reconstruction were resected and reconstructed with a medial antebrachial cutaneous nerve cable graft. The results following this reconstruction are pending long term follow-up due to the recent presentation of this case. The patient, however, reports significant reduction in her ulnar nerve-related pain.
Figure 1 – Pre-op Examination of Ulnar Nerve Injury. The patient sustained a laceration to her ulnar nerve. The ulnar nerve was reconstructed at an outside institution using a 4mm diameter, 1cm collagen conduit. Six months following the reconstruction, the patient presented to our institution with a complete ulnar neuropathy and a painful, non-advancing Tinel’s sign. The scar from the injury and subsequent surgery are observed, with the location of the Tinel’s sign delineated by “X”s.
Figure 2 – Exposure of Ulnar Nerve and Guyon’s Canal Release (A) The ulnar nerve was exposed throughout the arm and hand in order to identify the proper motor and sensory ulnar nerve topography. (B) Distal in the hand, the ulnar nerve was decompressed through Guyon’s canal and the deep motor branch. (C) The area of prior injury and reconstruction was identified.
Figure 3 – Identification of Ulnar Nerve Components. The ulnar nerve was decompressed through Guyon’s canal. Proximally, the motor component was identified lying
Figure 4 – Histological Analysis of Injured Ulnar Nerve Conduit. The area of injury and the previous reconstruction were identified and resected. (A) Histological evaluation revealed no nerve fibers distal to the nerve conduit. (B) In the middle of the conduit, histological assessment revealed no regenerative nerve fibers. (C) Proximal to the nerve conduit, many myelinated nerve fibers were visible.
Figure 5 – MABC Harvest for Graft Material. In the medial aspect of the right arm, the medial antebrachial cutaneous nerve (MABC) was identified adjacent to the basilic vein. (A) The proximal end of the MABC was inked so that the graft could be reversed for reverse polarity upon grafting in the hand. The posterior branch of MABC was also identified. (B) The distal end of the posterior branch of MABC was reconstructed to the sensory side of the median nerve using a short acellularized nerve allograft in an end-to-side fashion. This allowed for rudimentary spontaneous collateral sprouting from the sensory side of the median nerve across the allograft and into the distal territory of the posterior branch of the MABC. (C) The acellularized graft was transferred beneath the basilic vein. (D) The topography of the median nerve is noted with the sensory component lying laterally and the motor component medially. This topography allows the end-to-side nerve transfer to be directed towards the sensory side of the median nerve. To confirm the topography of the median nerve, a nerve stimulator can be used to stimulate the motor and sensory components of the median nerve. Stimulation of the sensory component will not result in muscle contractions.
Figure 6 – Reconstruction of Ulnar Nerve Gap with Cable Grafting. (A) The area of injury and previous reconstruction were identified and resected. (B) Three cables of the medial antebrachial cutaneous nerve (MABC), each 5cm in length, were used to bridge the nerve gap. (C) The MABC cable graft was inset with care to make sure that the proximal motor fascicular group was grafted to the distal motor fascicular group and the proximal sensory fascicular group was grafted to the distal sensory fascicular group.
History
A 20 year-old right-hand dominant female sustained a laceration to the ulnar aspect of her middle and distal right forearm upon accidentally falling through a window pane. At initial presentation, the patient was felt to be neurovascularly intact, including in the ulnar nerve distribution; her laceration was washed out and primarily closed. Upon follow-up with a hand specialist later that week, the patient complained of numbness in the ulnar digits, as well as weakness and pain in the hand. On physical examination, the patient lacked ulnar distribution pinprick sensation, demonstrated weak abduction of the digits, and was unable to cross her fingers. Perfusion to the hand was adequate. An ulnar nerve laceration was suspected, and the patient was taken to the OR for exploration approximately 2 weeks later. Lacerations to the ulnar artery and nerve were found, as well as to the flexor carpi ulnaris (FCU) tendon and small finger flexor digitorum superficialis (FDS) tendon. Under microscope visualization, the nerve stumps were trimmed back until healthy fascicles were present. A 1 cm gap was present between the nerve ends, which could not be re-approximated without tension. A 4 mm diameter commercially available collagen conduit was used to bridge the gap and was secured with 8-0 nylon epineural sutures. Additionally, the patient received tendon repairs and microsurgical ulnar artery repair. Postoperatively, the patient had no complications but failed to demonstrate ulnar nerve recovery. Approximately 3 months after her initial repair, she was referred to our institution.
Physical Examination
Complete intrinsic muscle atrophy and clawing of the ring and small fingers were present in the right hand. Sensory exam revealed no light touch sensation and no functional two-point discrimination in the right ulnar nerve distribution. Two-point discrimination in the median nerve distribution was 4-5 mm. Motor exam showed a positive Froment’s sign, inability to cross the fingers, pinch strength of 6 lb, and grip strength of 40 lb. Pinch and grip on the left were 15 lb and 65 lb, respectively. Tinel’s sign was present in the mid portion of the patient’s scar (non-advancing).
Diagnostic Testing
No diagnostic testing was performed given the patient’s physical examination, which was clearly consistent with a complete right ulnar neuropathy.
Management
Pre-operative: The patient was maintained in a protective splint for her ulnar clawing.
Surgical: Re-exploration was performed under 4.5x loupe magnification. The ulnar nerve was first identified in Guyon’s canal and decompression of Guyon’s canal was performed, along with decompression of the deep motor branch distally. The ulnar nerve was then followed proximally until the site of prior conduit reconstruction was reached. The conduit was excised; breadloafing through the conduit revealed dense scar tissue. Once the nerve had been cut back to healthy fascicles, a 4 cm gap was present. The medial antebrachial cutaneous nerve (MABC) was harvested through a separate incision. The topography of the ulnar nerve was mapped out both proximally and distally to ensure appropriate matching of sensory and motor components. Three cables of MABC, each 5 cm in length, were used to reconstruct the ulnar nerve under the operating microscope using 9-0 nylon microsutures. Fibrin glue was also used at the repair sites. The posterior branch of the MABC was reconstructed in an end-to-side fashion to the sensory side of the median nerve, whose sensory component was identified by its lack of motor activity with intraoperative nerve stimulation.
Post-operative: A pain pump placed intraoperatively was used for 3 days. The patient was then started on nortriptyline and referred for hand therapy. Initial hand therapy included scar mobilization and silicone sheeting, ulnar gliding exercises, passive range of motion exercises, and use of a hand-based ulnar nerve palsy splint.
Patient Outcomes
Two months postoperatively, sensory exam revealed no light touch sensation in the right ulnar nerve distribution. Pinch and grip strength were 4 and 20 lbs, respectively, compared to 12 and 65 lbs on the left. Tinel’s sign with ulnar radiation was present 3 cm proximal to the wrist crease. Given the typical nerve regeneration rate of one mm per day, or one inch per month, a longer period of follow-up is required to observe ulnar nerve recovery. This follow-up is pending.
Discussion
Important aspects of this case include: (1) using nerve autografts (the undisputed gold standard) for bridging gaps in critical nerves such as the ulnar nerve; (2) mapping out the motor and sensory topography of the injured nerve prior to grafting to ensure grafting of proximal sensory components to distal sensory components and proximal motor components to distal motor components; and (3) reconstructing the donor nerve (MABC) by transferring its distal stump to the side of an intact sensory nerve.
References
Ray WZ, Mackinnon SE. Management of nerve gaps: autografts, allografts, nerve transfers, and end-to-side neurorrhaphy. Exp Neurol. 2010 May; 223(1): 77-85.
Pfaeffle HJ, Waitayawinyu T, Trumble TE. Ulnar nerve laceration and repair. Hand Clin. 2007 Aug; 23(3): 291-9.
Brown JM, Yee A, Mackinnon SE. Distal median to ulnar nerve transfers to restore ulnar motor and sensory function within the hand: technical nuances. Neurosurgery. 2009 Nov; 65(5): 966-77. (Description of topographical mapping of the ulnar nerve)
Title: Digital Sensory Nerve Repair with Acellularized Nerve Allograft.
PNS ID: 110309-1, Published: 3/9/2011, Updated: 4/9/2011.
Author(s): Andrew Yee BS, Ida K. Fox MD.
Division of Plastic and Reconstructive Surgery, Washington University School of Medicine, St. Louis, MO.
Abstract: A 58-year-old left hand dominant patient sustained a stab-like laceration to the right hand with a non-serrated paring knife. The injury occurred on the volar aspect of the hand just proximal to the long finger. The wound was initially irrigated and sutured closed. The patient present immediately to our institution with complaints of sensory loss along the long finger. Upon examination, the patient had loss of sensation at the radial aspect of the long finger. Sensation was normal along the ulnar aspect of the long finger, and in the remaining fingers and the hand. The patient underwent surgical exploration. The digital nerve branch to the radial aspect of the long finger was found to be intact but longitudinally injured. The zone of injury was identified and resected until healthy proximal and distal ends of the digital nerve were seen. A 2cm acellularized nerve allograft was used to bridge the nerve gap. Five months post-operatively, the patient had recovered 10/10 sensation at the volar, radial aspect of the long finger. This case describes the successful use of a 2cm acellularized allograft to reconstruct a digital nerve gap. Our institution uses acellularized allografts for reconstruction of gaps less than 3cm in small, noncritical sensory nerves.
Figure 1 – Pre-operative Examination. This patient immediately presented to our institution with a sharp laceration wound to the right hand, which an outside institution had irrigated and sutured closed. The patient reported loss of sensation at the radial aspect of the long finger. (A,B) The purple X’s indicate the distribution of sensory loss. (C) Although the laceration was only a few centimeters across, the patient described a deep stab injury. A Tinel’s sign (purple star) was present near the site of injury.
Figure 2 – Exploration of Laceration Injury and Acellularized Allograft Nerve Repair. (A) Upon exploration, the palmar digital artery was found to be transected. The palmar digital nerve to the radial aspect of the long finger was found to be intact but injured. (B) The digital nerve had been longitudinally injured by the sharp object. (C) The zone of injury was identified and resected until healthy nerve was seen at both proximal and distal ends. (D) A 2cm acellularized allograft (Avance Nerve Graft, Axogen Inc.) was used to bridge the nerve gap for a tension-free repair. The nerve repair was tested for tension by putting the long finger through full flexion and extension.
Figure 3 – Post-op Examination and Pain Diagram. Five months post-operatively, the patient reported recovery of volar sensation at the radial aspect of the long finger, but also reported some numbness dorsally. The dorsal branch was not included in the repair, which could explain the numbness. The patient reported 10/10 sensation, 2.83 Semmes-Weinstein, 3mm two-point discrimination at the tip and 4mm two-point discrimination over the middle phalanx at both the radial and ulnar aspects of the long finger. A slight Tinel’s sign was present over the site of the injury.
Title: Failed Endoscopic Carpal Tunnel Release and Stem Cell Injection Nerve Reconstruction.
PNS ID: 110307-1, Published: 3/7/2011, Updated: 3/7/2011.
Author(s): Andrew Yee BS, Susan E. Mackinnon MD.
Division of Plastic and Reconstructive Surgery, Washington University School of Medicine, St. Louis, MO.
Abstract: The following case describes a median nerve injury following an endoscopic carpal tunnel release. The median nerve injury was noted at the time of the surgery and the incision was opened and an attempt was made to repair the median nerve. Unfortunately, the primary reconstruction was not successful and the patient failed medical management, which included a high dose of anti-neuropathic pain medications to relieve her pain. On clinical examination at our institution, she had thenar motor function and normal sensation in her thumb, but otherwise disabling pain and no sensation in the index, long, and radial side of the ring finger. At surgery, the uninjured portion of the median nerve (thenar motor function and sensation to the thumb) was protected. The remainder of the median nerve, which was injured, was managed with nerve grafts. In order to avoid sural nerve graft harvest from her lower extremity, the medial antebrachial cutaneous nerve and the third webspace component of the median nerve proximal to the zone of injury were used for cable grafting. The distal end of the medial antebrachial cutaneous nerve was end-to-side transferred to the sensory component of the median nerve (superior or lateral aspect) in order to recovery rudimentary sensation for donor deficit. Similarly, the distal end of the third webspace was end-to-side transferred to the sensory component of the ulnar nerve to also recovery rudimentary sensation to the non-critical third webspace component of the median nerve. Utilizing a medial antebrachial cutaneous nerve graft and a third webspace nerve graft allowed to keep all donor graft deficits to the same upper extremity.
Figure 1 – History and Positioning. Patient presented at our institution two years following a complex history that included a severe median nerve injury and a failed primary nerve repair. The patient had bilateral endoscopic carpal tunnel releases (ECTR) by an outside institution and it was noted at the time of the right ECTR that the majority of the median nerve has been lacerated. The lacerated median nerve was immediately primarily repaired. Six months following without resolution of median nerve pain, stem cells from her hip were injected into her wrist without relief of pain. During examination at our institution, the patient had good thenar motor function in the right hand and thumb sensation, but otherwise no median nerve sensation in the hand except for severe pain.
Figure 2 – Exposure of Median Nerve and Intraneurolysis. (A) The median nerve was identified proximal and distal to the zone of injury. It was found to have a course within dense scar tissue. (B) The median nerve was isolated from the scar tissue and distal neurolysis revealed the sensory branches of the median nerve. The intact thenar motor branch and sensory fascicles to the thumb were protected. Suture material was found within the remainder of the injured median nerve. (C) Proximal neurolysis revealed the fascicular anatomy of the median nerve. The 3rd webspace is neurolyzed proximally so that it can be used as graft material.
Figure 4 – 2nd Webspace Grafted with a Medial Antebrachial Cutaneous Nerve Graft. (A) The medial antebrachial cutaneous nerve (MABC) was isolated within the arm for donor material. (B) The MABC was than transected with the distal end transferred to the sensory component of the median nerve through and end-to-side epineural window fashion. The sensory component of the median nerve is located on the superior aspect of the median nerve. Note that in this image, the median nerve has been rotated so that it appears to be on the inferior portion. (C) The MABC graft was used to repair the remaining portion of the median nerve. The thenar branch and remaining sensory branches to the thumb were protected and were found to be not injured.
Figure 5 – Pre-operative and Post-operative Pain Diagram. (A) Pre-operative pain diagram demonstrates pain upon presentation 2 years after a right hand endoscopic carpal tunnel release, failed primary median nerve repair, and stem cell injection into the wrist. (B) Post-operative following the revision reconstruction by our institution, pain was reduced significantly.
