Distal anterior interosseous nerve transfer to the deep motor branch of the ulnar nerve for reconstruction of high ulnar nerve injuries

[Granular cells tumour (Abrikossof) of the ulnar nerve at the arm. A case report and literature review]

INTRODUCTION

Granular cell tumours are extremely rare on peripheral nerves, with an incidence of 0.029% of pathologic samples. In a literature review, we found only 5 cases involving the ulnar nerve, although considered the most frequently involvement nerve.

CASE REPORT

A 32 year-old female from the French West Indies presented a severe arm pain with deficit of interosseous hand muscles. Imaging studies were in favour of a Schwanoma, but during surgery, we found an unremovable intra-neural tumour. Nerve biopsy revealed a granular cell tumour. Initial decision was observation only. However, within two years, tumour increased in size, along with pain aggravation and functional deficit. We performed a nerve resection (with adequate margins) with reconstruction using sural nerve graft associated with a neurotisation of the motor branch with the anterior interosseus nerve. At two years follow-up, no recurrence was observed. The scar is hypersensitive with moderate neuropathic pain. There is a sensory reinnervation of the fourth finger, with no motor recovery of the hand. We observed a slight recovery of flexor profundus tendons, which, in turn increased the claw hand.

DISCUSSION

The five cases described in the literature were managed differently (biopsy only, excision, excision with reconstruction), with modest results. There is no recommended treatment. Our case is the first at arm level. We were able to perform complete resection, but functional result is poor.

CONCLUSION

Granular cell tumours require treatment if symptomatic (pain, function loss), but, at the moment, there is no recommended treatment.

Supercharge End-to-Side Nerve Transfer: Systematic Review

Background: To decrease the time to reinnervation of the intrinsic motor end plates after high ulnar nerve injuries, a supercharged end-to-side (SETS) anterior interosseous to ulnar motor nerve transfer has been proposed. The purpose of this study was to compile and review the indications, outcomes, and complications of SETS anterior interosseous to ulnar motor nerve transfer. Methods: A literature search was performed, identifying 73 papers; 4 of which met inclusion and exclusion criteria, including 78 patients. Papers included were those that contained the results of SETS between the years 2000 and 2018. Data were pooled and analyzed focusing on the primary outcomes: intrinsic muscle recovery and complications. Results: Four studies with 78 patients met inclusion and exclusion criteria. Most patients (33.3%) underwent SETS for an ulnar nerve lesion in continuity, the average age was 46.5 years, and the average follow-up was 10 months. The average duration of symptoms before surgery was 99 weeks, all patients had weakness and numbness, nearly all (96%) had atrophy, and half (53%) had pain. Grip and key pinch strength improved 202% and 179%, respectively, from the preoperative assessment. The vast majority (91.9%) recovered intrinsic function at an average of 3.7 months. Other than 8% of patients who did not recover intrinsic strength, no other complications were reported in any of the 78 patients. Conclusions: The SETS is a successful procedure with low morbidity, which may restore intrinsic function in patients with proximal nerve injuries.

End-to-Side Anterior Interosseous Nerve Transfer: A Valuable Alternative for Traumatic High Ulnar Nerve Palsy

BACKGROUND

The prognosis of high ulnar nerve injury is poor despite nerve repair or grafting. Anterior interosseous nerve (AIN) transfers provide a satisfactory recovery. However, the efficacy of end-to-side (ETS) AIN transfer and optimal timing in Sunderland grade IV/V of high ulnar nerve injury is lacking.

OBJECTIVE

The goals were to compare the outcomes of high ulnar nerve injury managed with ETS AIN transfers with those managed with conventional procedures (nerve repair or graft only) and identify differences between early and delayed transfers.

METHODS

Patients with isolated high ulnar nerve injury (Sunderland grade IV/V) from 2010 to 2017 were recruited. Patients with conventional treatments and AIN transfers were designated as the control and AIN groups, respectively. Early transfer was defined as the AIN transfer performed within 8 weeks postinjury. Outcomes were measured and analyzed by the British Medical Research Council (BMRC) score, grip strength, and pinch strength.

RESULTS

A total of 24 patients with high ulnar nerve injury (Sunderland grade IV/V) were included. There were 11 and 13 patients in the control and AIN groups, respectively. In univariate analysis, both early and delayed AIN transfers demonstrated significantly better motor recovery among BMRC score and strength of grip and pinch at 12 months (P < 0.05). No statistical significance was found between early and delayed transfer. In multivariate analysis, both early and delayed transfers were regarded as strong and independent factors for motor recovery of ulnar nerve. Compared with the control, early [odds ratio (OR), 1.83; P < 0.001] and delayed (OR, 1.59; P < 0.001) transfers showed significant improvement with regard to BMRC scores. The pinch strength in early (OR, 31.68; P < 0.001) and delayed (OR, 26.45; P < 0.001) transfers was also significantly better.

CONCLUSION

The ETS AIN transfer, in either early or delayed fashion, significantly improved intrinsic motor recovery in high ulnar nerve injuries classified as Sunderland grade IV/V. The early transfer group demonstrated a trend toward better functional recovery with less downtime.

Nerve transfers in the upper extremity: A review

Injury of the brachial plexus and peripheral nerve often result in significant upper extremity dysfunction and disability. Nerve transfers are replacing other techniques as the gold standard for brachial plexus and other proximal peripheral nerve injuries. These transfers require an intimate knowledge of nerve topography, a technically demanding Intraneural dissection and require extensive physical therapy for retraining. In this review, we present a summary of the most widely accepted nerve transfers in the upper extremity described in the current literature.

Trends in Nerve Transfer Procedures Among Board-Eligible Orthopedic Hand Surgeons

Purpose

Enthusiasm for peripheral nerve transfers increased over the past several years, but further studies are still needed to establish the role of these procedures in peripheral nerve reconstruction. The primary goal of this study was to describe the frequency of nerve transfer surgery among newly trained orthopedic surgeons.

Methods

We queried the American Board of Orthopaedic Surgery Part II case log database for all nerve reconstruction Current Procedural Terminology codes for examination years 2004 to 2018 for surgeries performed between 2003 and 2017. Information collected for each patient included examination year, year of surgery, surgeon fellowship training subspecialty, geographic region (as defined by the American Board of Orthopaedic Surgery Part II case log database), patient age, and patient sex.

Results

A total of 3,359 nerve reconstruction cases were logged by 1,542 individual candidates from examination years 2004 to 2018. Of the nerve reconstruction codes, 2.1% were nerve transfer codes. There was a statistically significant increase in the proportion of nerve transfer codes over the study period, from 0% of nerve reconstruction codes in examination years 2004 to 2006 to 4.1% of nerve reconstruction codes in examination years 2016 to 2018 (Z = –6.82; P < .001).

Conclusions

There has been an increase in the number of nerve transfer procedures relative to all nerve reconstruction codes for peripheral nerve conditions.

Clinical relevance

There is a modest but significant increase in nerve transfer procedures over time among newly trained orthopedic surgeons, which suggests the need for long-term outcomes studies for nerve transfers procedures performed in the setting of peripheral nerve conditions.

Reliability of focal identification of motor fascicles of the ulnar nerve proximal to the wrist: an anatomical study

We investigated whether motor fascicles of the ulnar nerve can be reliably identified proximal to the wrist. In 17 cadaveric upper limbs, the anterior interosseous nerve was transected at its arborization in the pronator quadratus and transposed to the palmar aspect of the ulnar nerve. The motor fascicular bundle was identified at this level after distinguishing the intraneural epineural involution by microsurgical probing. The motor branch was identified in Guyon's canal and traced retrograde via intraneural dissection to assess accuracy of the original identification. The motor fascicular bundle was found to have been correctly identified in all specimens. We conclude that local anatomic landmarks allow for the motor fascicular group to be correctly identified. Therefore, retrograde, internal dissection of the ulnar nerve is not likely to be required for reliable transfer of anterior interosseous nerve to ulnar nerve motor fascicles.

Comparison Between Supercharged Ulnar Nerve Repair by Anterior Interosseous Nerve Transfer and Isolated Ulnar Nerve Repair in Proximal Ulnar Nerve Injuries

PURPOSE

To compare combined ulnar nerve repair with supercharged end-to-side anterior interosseous nerve to ulnar motor nerve transfer (UR+SETS) with conventional isolated ulnar repair techniques in proximal ulnar nerve transection, with respect to intrinsic muscle power recovery and claw hand deformity correction.

METHODS

We conducted a comparative matched-paired series prospectively on 21 patients with proximal ulnar nerve transection injury. Eleven patients were managed by UR+SETS and 10 by isolated ulnar repair. The outcome was reported at 3, 6, 12, and 18 months using the score of Birch and Raji and Brand's criteria.

RESULTS

A total of 21 patients with acute proximal ulnar nerve transection injury had completed 18 months' follow-up. We observed better results in the UR+SETS group regarding the return of intrinsic function and reduction of deformity with earlier improvement in the score of Birch and Raji and Brand's criteria.

CONCLUSIONS

In the short term, UR+SETS transfer appears to result in better intrinsic muscle reinnervation and clawing deformity correction after proximal ulnar nerve transection injury.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic II.

The Surgical Management of Nerve Gaps: Present and Future

Peripheral nerve injuries can result in significant morbidity, including motor and/or sensory loss, which can affect significantly the life of the patient. Nowadays, the gold standard for the treatment of nerve section is end-to-end neurorrhaphy. Unfortunately, in some cases, there is segmental loss of the nerve trunk. Nerve mobilization allows primary repair of the sectioned nerve by end-to-end neurorrhaphy if the gap is less than 1 cm. When the nerve gap exceeds 1 cm, autologous nerve grafting is the gold standard of treatment. To overcome the limited availability and the donor site morbidity, other techniques have been used: vascularized nerve grafts, cellular and acellular allografts, nerve conduits, nerve transfers, and end-to-side neurorrhaphy. The purpose of this review is to present an overview of the literature on the applications of these techniques in peripheral nerve repair. Furthermore, preoperative evaluation, timing of repair, and future perspectives are also discussed.

Surgery for nerve injury: current and future perspectives

In this review article, the authors offer their perspective on nerve surgery for nerve injury, with a focus on recent evolution of management and the current surgical management. The authors provide a brief historical perspective to lay the foundations of the modern understanding of clinical nerve injury and its evolving management, especially over the last century. The shift from evaluation of the nerve injury using macroscopic techniques of exploration and external neurolysis to microscopic interrogation, interfascicular dissection, and internal neurolysis along with the use of intraoperative electrophysiology were important advances of the past 50 years. By the late 20th century, the advent and popularization of interfascicular nerve grafting techniques heralded a major advance in nerve reconstruction and allowed good outcomes to be achieved in a large percentage of nerve injury repair cases. In the past 2 decades, there has been a paradigm shift in surgical nerve repair, wherein surgeons are not only directing the repair at the injury zone, but also are deliberately performing distal-targeted nerve transfers as a preferred alternative in an attempt to restore function. The peripheral rewiring approach allows the surgeon to convert a very proximal injury with long regeneration distances and (often) uncertain outcomes to a distal injury and repair with a greater potential of regenerative success and functional recovery. Nerve transfers, originally performed as a salvage procedure for severe brachial plexus avulsion injuries, are now routinely done for various less severe brachial plexus injuries and many other proximal nerve injuries, with reliably good to even excellent results. The outcomes from nerve transfers for select clinical nerve injury are emphasized in this review. Extension of the rewiring paradigm with nerve transfers for CNS lesions such as spinal cord injury and stroke are showing great potential and promise. Cortical reeducation is required for success, and an emerging field of rehabilitation and restorative neurosciences is evident, which couples a nerve transfer procedure to robotically controlled limbs and mind-machine interfacing. The future for peripheral nerve repair has never been more exciting.

Prognosis of Traumatic Ulnar Nerve Injuries: A Systematic Review

Ulnar nerve injury (UNI) is not uncommon and often results in incomplete motor recovery after the initial nerve repair and requires secondary functional reconstruction. To clarify the prognosis and predicting factor of UNI, and if it is reasonable to wait after the initial repair, a systematic literature review from PubMed computerized literature database and Google scholar was performed. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist and guidelines were followed to develop the search protocol for this literature review. Two reviewers independently assessed titles, abstracts, and full-text articles, and a third reviewer resolved any disagreements. Seventeen articles with 260 cases were found with sufficient data and enough follow-up. After multiple logistic regression, age, injury level, gap of lesion, and delayed time to surgery were significant prognostic factors in UNI. If considering only high-level injuries (injury at or above proximal forearm), age became the only predicting factor. In cases with likely poor prognosis, their motor recovery tends to be unsatisfactory, and observation for months after the initial repair might not be reasonable. Other surgical interventions such as early nerve transfer may be an option to improve the outcome.

Transferring the Motor Branch of the Opponens Pollicis to the Terminal Division of the Deep Branch of the Ulnar Nerve for Pinch Reconstruction

PURPOSE

With ulnar nerve injuries, paralysis of the first dorsal interosseous (FDI) and the adductor pollicis (ADP) muscles weakens pinch. The likelihood that these muscles will be reinnervated following ulnar nerve repair around the elbow is very low. To overcome this obstacle, we propose a more distal repair: transferring the opponens pollicis motor branch (OPB) to the terminal division of the deep branch of the ulnar nerve (TDDBUN).

METHODS

We dissected 10 embalmed hands to study the anatomy of the thenar branches of the median nerve and TDDBUN. We also operated on 3 patients with recent ulnar nerve injuries around the elbow, suturing the ulnar nerve and transferring the OPB to the TDDBUN. Before and after surgery, we measured grasp, key pinch, and pinch-to-zoom strength using dynamometers. Pinch-to-zoom gesture consists of moving the index finger and thumb pulp toward each other for zooming out of an image on screen. Patients were followed for at least 15 months.

RESULTS

The thenar branch of the median nerve innervated the abductor pollicis brevis and opponens pollicis in all specimens, but only half the superficial head of the flexor pollicis brevis. The TDDBUN gave off a single motor branch to the transverse head of the ADP, 1 or 2 branches to the oblique head, and a final branch to the FDI. The ratio of myelinated fibers between the OPB and the TDDBUN was 3:5. Relative to the normal side, pinch-to-zoom strength was mostly affected by the ulnar nerve lesion, with strength decreased by 80% to 90%. After surgery, we observed reinnervation of the FDI and an 80% to 90% improvement in pinch-to-zoom strength.

CONCLUSIONS

Transferring the OPB to the TDDBUN provided reinnervation of the FDI and ADP, thereby contributing to pinch strength improvement.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

“In Situ Vascular Nerve Graft” for Restoration of Intrinsic Hand Function: An Anatomical Study

Background: In combined high median and ulnar nerve injury, transfer of the posterior interosseous nerve branches to the motor branch of the ulnar nerve (MUN) is previously described in order to restore intrinsic hand function. In this operation a segment of sural nerve graft is required to close the gap between the donor and recipient nerves. However the thenar muscles are not innervated by this nerve transfer. The aim of the present study was to evaluate whether the superficial radial nerve (SRN) can be used as an “in situ vascular nerve graft” to connect the donor nerves to the MUN and the motor branch of median nerve (MMN) at the same time in order to address all denervated intrinsic and thenar muscles.

Methods: Twenty fresh male cadavers were dissected in order to evaluate the feasibility of this modification of technique. The size of nerve branches, the number of axons and the tension at repair site were evaluated.

Results: This nerve transfer was technically feasible in all specimens. There was no significant size mismatch between the donor and recipient nerves

Conclusions: The possible advantages of this modification include innervation of both median and ulnar nerve innervated intrinsic muscles, preservation of vascularity of the nerve graft which might accelerate the nerve regeneration, avoidance of leg incision and therefore the possibility of performing surgery under regional instead of general anesthesia. Briefly, this novel technique is a viable option which can be used instead of conventional nerve graft in some brachial plexus or combined high median and ulnar nerve injuries when restoration of intrinsic hand function by transfer of posterior interosseous nerve branches is attempted.

Cubital Tunnel Syndrome: Current Concepts

Cubital tunnel syndrome is the second most common upper extremity compressive neuropathy. In recent years, rates of surgical treatment have increased, and the popularity of in situ decompression has grown. Nonsurgical treatment, aiming to decrease both compression and traction on the ulnar nerve about the elbow, is successful in most patients with mild nerve dysfunction. Recent randomized controlled trials assessing rates of symptom resolution and ultimate success have failed to identify a preferred surgical procedure. Revision cubital tunnel surgery, most often consisting of submuscular transposition, may improve symptoms. However, ulnar nerve recovery after revision cubital tunnel surgery is less consistent than that after primary cubital tunnel surgery.

Peripheral nerve intersectional repair by bi-directional induction and systematic remodelling: biodegradable conduit tubulization from basic research to clinical application

In terms of the clinical effect of peripheral nerve injury repair, the biological degradable conduit 2 mm small gap tubulization is far better than the traditional epineurial or perineurium neurorrhaphy. The assumption of the bi-directional induction between the central system and the terminal effector during peripheral nerve regeneration is purposed and proved in clinical by our group. The surgical approach of transferring a portion of or the whole contralateral C7 nerve to repair a part of or the whole ipsilateral brachial plexus injury is clinically promoted, in which the most important idea and practice is to use the cone conduit designed by the group to repair thick nerves with fine nerves. Some of the patients suffering from cerebral palsy or cerebral haemorrhage and those who got cerebral infarction yet have not reached recovery after 3-6 months could regain some functions of the ipsilateral upper limb and improve the life quality by transfer of a portion of or the whole contralateral C7 nerve and connection by cone conduit.

Transfer of extensor digiti minimi and extensor carpi ulnaris nerve branches to the intrinsic motor nerve branches: A histological study on cadaver

BACKGROUND

In cases of high ulnar and median nerve palsy, result of nerve repair in term of intrinsic muscle recovery is unsatisfactory. Distal nerve transfer can alleviate the regeneration time and improve the results. Transfer of the extensor digiti minimi (EDM) and extensor carpi ulnaris (ECU) nerve branches to the deep branch of ulnar nerve (DBUN)/recurrent branch of median nerve (RMN) at wrist had been used to restore intrinsic hand function but, incomplete recovery occurred. The axon count at the donor nerve has a strong influence on the final results.

HYPOTHESIS

This cadaveric study aims to analyses the histology of this nerve transfer to evaluate whether these donor nerves are suitable for this transfer or another donor nerve may be considered.

MATERIALS AND METHODS

Ten cadaveric upper limbs dissected to identify the location of the EDM, ECU, RMN and DBUN. Surface area, fascicle count, and axon number was determined by histological methods.

RESULTS

The mean of axon number in the EDM, ECU, RMN and DBUN branches was 5931, 7355, 30960 and 35426, respectively. In this study, the number of axons in the EDM and ECU branches was 37% (13281/35426) of that in the DBUN. Also, the number of axons in the EDM and ECU branches was 42% (13281/30960) of that in the RMN.

CONCLUSION

The axon count data showed an unfavorable match between the EDM, ECU and DBUN/RMN. Therefore, it is suggested that another donor nerve with higher axon number to be considered.

TYPE OF STUDY

Cadaver study (histological study).

Nerve Transfer Versus Nerve Graft for Reconstruction of High Ulnar Nerve Injuries

PURPOSE

To assess the efficacy of nerve transfer versus nerve grafting in restoring motor and sensory hand function in patients with complete, isolated high ulnar nerve injuries.

METHODS

A retrospective chart review was performed, at a minimum 2 years of follow-up, of 52 patients suffering complete, isolated high ulnar nerve injury between January 2006 and June 2013 in one specialized hand surgery unit. Twenty-four patients underwent motor and sensory nerve transfers (NT group). Twenty-eight patients underwent sural nerve grafting (NG group). Motor recovery, return of sensibility and complications were examined as outcome measures. The Medical Research Council scale was applied to evaluate sensory and motor recovery. Grip and pinch strengths of the hand were measured.

RESULTS

Twenty of 24 patients (83.33%) in the NT group regained M3 grade or greater for the adductor pollicis, the abductor digiti minimi, and the medial 2 lumbricals and interossei, compared with only 16 of 28 patients (57.14%) in the NG group. Means for percentage recovery of grip strengths compared with the other healthy hand were significantly higher for the NT group than the NG group. Sensory recovery of S3 or greater was achieved in more than half of each group with no significant difference between groups.

CONCLUSIONS

Nerve transfer is favored over nerve grafting in managing high ulnar nerve injuries because of better improvement of motor power and better restoration of grip functions of the hand.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

The Present and Future for Peripheral Nerve Regeneration

Peripheral nerve injury can have a potentially devastating impact on a patient's quality of life, resulting in severe disability with substantial social and personal cost. Refined microsurgical techniques, advances in peripheral nerve topography, and a better understanding of the pathophysiology and molecular basis of nerve injury have all led to a decisive leap forward in the field of translational neurophysiology. Nerve repair, nerve grafting, and nerve transfers have improved significantly with consistently better functional outcomes. Direct nerve repair with epineural microsutures is still the surgical treatment of choice when a tension-free coaptation in a well-vascularized bed can be achieved. In the presence of a significant gap (>2-3 cm) between the proximal and distal nerve stumps, primary end-to-end nerve repair often is not possible; in these cases, nerve grafting is the treatment of choice. Indications for nerve transfer include brachial plexus injuries, especially avulsion type, with long distance from target motor end plates, delayed presentation, segmental loss of nerve function, and broad zone of injury with dense scarring. Current experimental research in peripheral nerve regeneration aims to accelerate the process of regeneration using pharmacologic agents, bioengineering of sophisticated nerve conduits, pluripotent stem cells, and gene therapy. Several small molecules, peptides, hormones, neurotoxins, and growth factors have been studied to improve and accelerate nerve repair and regeneration by reducing neuronal death and promoting axonal outgrowth. Targeting specific steps in molecular pathways also allows for purposeful pharmacologic intervention, potentially leading to a better functional recovery after nerve injury. This article summarizes the principles of nerve repair and the current concepts of peripheral nerve regeneration research, as well as future perspectives. [Orthopedics. 2017; 40(1):e141-e156.].

Supinator to ulnar nerve transfer via in situ anterior interosseous nerve bridge to restore intrinsic muscle function in combined proximal median and ulnar nerve injury: a novel cadaveric study

BACKGROUND

In cases of high ulnar nerve palsy, result of nerve repair in term of intrinsic muscle recovery is unsatisfactory. Distal nerve transfer can diminish the regeneration time and improve the results. But, there was no perfect distal nerve transfer for restoring intrinsic hand function in combined proximal median and ulnar nerve injuries. This cadaveric study aims to evaluate the possibility and feasibility of supinator nerve transfer to motor branch of ulnar nerve (MUN).

METHODS

Ten cadaveric upper limbs dissected to identify the location of the supinator branch, anterior interosseous nerve (AIN), and MUN. The AIN was cut from its origin and transferred to the supinator branches. Also, the AIN was distally cut and transferred to the MUN. After nerve coaptation, surface area, fascicle count, and axon number were determined by histologic methods.

RESULTS

In all limbs, the proximal and distal stumps of AIN reached the supinator branch and the MUN without tension, respectively. The mean of axon number in the supinator, proximal stump of AIN, distal stump of AIN and MUN branches were 32,426, 45,542, 25,288, and 35,426, respectively.

CONCLUSIONS

This study showed that transfer of the supinator branches to the MUN is possible via the in situ AIN bridge. The axon count data showed a favorable match between the supinator branches, AIN, and MUN. Therefore, it is suggested that this technique can be useful for patients with combined high median and ulnar nerve injuries.

High Ulnar Nerve Injuries: Nerve Transfers to Restore Function

Peripheral nerve injuries are challenging problems. Nerve transfers are one of many options available to surgeons caring for these patients, although they do not replace tendon transfers, nerve graft, or primary repair in all patients. Distal nerve transfers for the treatment of high ulnar nerve injuries allow for a shorter reinnervation period and improved ulnar intrinsic recovery, which are critical to function of the hand.

Restoration of ulnar nerve motor function by pronator quadratus motor branch: an anatomical study

BACKGROUND

The traditional surgical approach to repair of brachial plexus lesions involves use of whole segment ulnar nerve graft for contralateral seventh cervical (cC7) nerve root transfer, which sabotages the possibility of ulnar nerve recovery. We assessed the anatomical feasibility of a new approach that involves preservation of the motor branch of ulnar nerve (MBUN), for a later stage repair using the recovered pronator quadratus motor branch (PQMB), subsequent to the cC7 transfer procedure.

METHODS

Twenty-seven adult cadaver arms and one side of fresh adult cadaver were used in this study. The anterior interosseous nerve and its PQMB, as well as the motor and sensory branches of the ulnar nerve were dissected. The distances from the end of PQMB to the mid-point of a line joining the radial styloid and ulnar styloid, as well as to the point of divergence of the ulnar nerve, were measured. The MBUN was dissected from distal to proximal and the maximum length was measured. The diameter and number of axons of the nerve branches were also recorded.

RESULTS

The distance from the end of the PQMB to the midpoint of the radial styloid and ulnar styloid was 6.04 ± 0.52 cm, and that to the point of divergence of the ulnar nerve was 8.02 ± 0.63 cm. The maximum length of the MBUN after its dissociation was 9.70 ± 1.38 cm. The mean diameters of axons of the MBUN and PQMB were 0.09 ± 0.02 cm and 0.05 ± 0.01 cm, respectively. The corresponding mean numbers of axons were 2913 ± 624 and 757 ± 183, respectively.

CONCLUSIONS

The results indicate that the PQMB is suitable for transferring to the MBUN without nerve graft. This anatomical study paves the way for further testing of this new procedure after cC7 transfer in clinical settings.

Nerve Transfers in the Upper Extremity: A Practical User's Guide

Nerve injuries above the elbow are associated with a poor prognosis, even with prompt repair and appropriate rehabilitation. The past 2 decades have seen the development of numerous nerve transfer techniques, by which a denervated peripheral target is reinnervated by a healthy donor nerve. Nerve transfers are indicated in proximal brachial plexus injuries where grafting is not possible or in proximal injuries of peripheral nerves with long reinnervation distances. Nerve transfers represent a revolution in peripheral nerve surgery and offer the potential for superior functional recovery in severe nerve injuries. However, the techniques have not been universally adopted due in part to a misconception that nerve transfers can only be understood and performed by superspecialists. Nerve transfer procedures are not technically difficult and require no specialized equipment. Numerous transfers have been described, but there are a handful of transfers for which there is strong clinical evidence. To restore shoulder abduction and external rotation in upper trunk brachial plexus injury, the key transfers are the spinal accessory to suprascapular nerve and the medial triceps branch to axillary nerve. For elbow flexion, the flexor carpi ulnaris branch of ulnar nerve to the biceps and brachialis branches of the musculocutaneous nerve is the key transfer. For ulnar intrinsic function, the distal anterior interosseous nerve to ulnar motor branch transfer has yielded excellent functional results. Nerve transfers form a therapeutic triad with traditional tendon transfers and functional motor unit rehabilitation which, when applied appropriately, can yield excellent functional results in complex nerve injuries. Nerve transfers are a powerful yet underused tool for proximal nerve injuries, which offer hope for traditionally discouraging injuries.

Useful Functional Outcome Can Be Achieved After Motor Nerve Transfers in Management of the Paralytic Hand. An Observational Study

BACKGROUND

Nerve transfers have demonstrated encouraging outcomes in peripheral nerve reconstructions compared with the conventional direct repair or grafting.

QUESTIONS/PURPOSES

We aimed to identify whether the patient's demographics, delay to surgery, degree of loss of grip and pinch strengths, mechanism of injury, and compliance to hand therapy have an impact on the functional outcome of motor nerve transfers in patients with paralytic hand.

METHODS

Fifty-five patients with a mean age of 31.05 (18-48) years with complete isolated high injuries of radial, ulnar, and median nerves, who underwent motor nerve transfers, were reviewed. The outcome was assessed using the Medical Research Council (MRC) scale and measurement of grip and pinch strengths of the hand at minimum 1-year follow-up (mean of 14.4 (12-18) months). Patient's age and gender, delay to surgery, body mass index (BMI), degree of loss of grip and pinch strengths, educational level, occupation, mechanism of injury, and compliance to hand therapy were analyzed to determine their impact on the extent of recovery of hand function.

RESULTS

Forty of fifty five (72.73%) patients regained useful functional recovery (M3-M4) with satisfactory grip hand functions. Worse motor recovery was observed in older ages, delayed surgical intervention, higher BMI, and greater postoperative loss of grip and pinch strengths in comparison to the healthy opposite hand. Better outcomes are significantly associated with higher educational level and postoperative compliance to hand therapy. Contrarily, there was no significant association between gender, occupation, mechanism of injury, and achievement of useful functional recovery.

CONCLUSIONS

Successful nerve transfers are expected with experienced skilled surgeons. However, outstanding outcomes are not the standard, with about one fourth failing to achieve M3 grade. The educational level, hand dominance, compliance to hand therapy, loss of grip and pinch strengths, age, injury-surgery interval, and BMI are possible predictors of patients' outcome.

Nerve transfers and neurotization in peripheral nerve injury, from surgery to rehabilitation

Peripheral nerve injury (PNI) and recent advances in nerve reconstruction (such as neurotization with nerve transfers) have improved outcomes for patients suffering peripheral nerve trauma. The purpose of this paper is to bridge the gap between the electromyographer/clinical neurophysiologist and the peripheral nerve surgeon. Whereas the preceding literature focuses on either the basic science behind nerve injury and reconstruction, or the surgical options and algorithms, this paper demonstrates how electromyography is not just a 'decision tool' when deciding whether to operate but is also essential to all phases of PNI management including surgery and rehabilitation. The recent advances in the reconstruction and rehabilitation of PNI is demonstrated using case examples to assist the electromyographer to understand modern surgical techniques and the unique demands they ask from electrodiagnostic testing.

Nerve Transfers to Restore Upper Extremity Function in Cervical Spinal Cord Injury: Update and Preliminary Outcomes

BACKGROUND

Cervical spinal cord injury can result in profound loss of upper extremity function. Recent interest in the use of nerve transfers to restore volitional control is an exciting development in the care of these complex patients. In this article, the authors review preliminary results of nerve transfers in spinal cord injury.

METHODS

Review of the literature and the authors' cases series of 13 operations in nine spinal cord injury nerve transfer recipients was performed. Representative cases were reviewed to explore critical concepts and preliminary outcomes.

RESULTS

The nerve transfers used expendable donors (e.g., teres minor, deltoid, supinator, and brachialis) innervated above the level of the spinal cord injury to restore volitional control of missing function such as elbow extension, wrist extension, and/or hand function (posterior interosseous nerve or anterior interosseous nerve/finger flexors reinnervated). Results from the literature and the authors' patients (after a mean postsurgical follow-up of 12 months) indicate gains in function as assessed by both manual muscle testing and patients' self-reported outcomes measures.

CONCLUSIONS

Nerve transfers can provide an alternative and consistent means of reestablishing volitional control of upper extremity function in people with cervical level spinal cord injury. Early outcomes provide evidence of substantial improvements in self-reported function despite relatively subtle objective gains in isolated muscle strength. Further work to investigate the optimal timing and combination of nerve transfer operations, the combination of these with traditional treatments (tendon transfer and functional electrical stimulation), and measurement of outcomes is imperative for determining the precise role of these operations.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Motor Nerve Transfers

Brachial plexus and peripheral nerve injuries are exceedingly common. Traditional nerve grafting reconstruction strategies and techniques have not changed significantly over the last 3 decades. Increased experience and wider adoption of nerve transfers as part of the reconstructive strategy have resulted in a marked improvement in clinical outcomes. We review the options, outcomes, and indications for nerve transfers to treat brachial plexus and upper- and lower-extremity peripheral nerve injuries, and we explore the increasing use of nerve transfers for facial nerve and spinal cord injuries. Each section provides an overview of donor and recipient options for nerve transfer and of the relevant anatomy specific to the desired function.

Anatomical and histomorphometric observations on the transfer of the anterior interosseous nerve to the deep branch of the ulnar nerve

This study focuses on the anatomical and histomorphometric features of the transfer of the anterior interosseous nerve to the deep motor branch of the ulnar nerve. The transfer was carried out in 15 cadaver specimens and is described using relevant anatomical landmarks. Nerve samples of donor and target nerves were histomorphometrically analysed and compared. The superficial and the deep ulnar branches had to be separated from each other for a length of 67 mm (SD 12; range 50-85) to reach the site of coaptation. We identified a suitable site for coaptation lying proximal to the pronator quadratus muscle, 202 mm (SD 15; range 185-230) distal to the medial epicondyle of the humerus. The features of the anterior interosseous nerve included a smaller nerve diameter, smaller cross-sectional area of fascicles, fewer fascicles and axons, but a similar axon density. The histomorphometric inferiority of the anterior interosseous nerve raises a question about whether it should be transferred only to selected parts of the deep motor branch of the ulnar nerve.Level III.

Management of Iatrogenic Ulnar Nerve Transection

A case of iatrogenic ulnar nerve laceration at the elbow is presented. Five subsequent surgeries over the course of the ensuing 20 months were performed to address this complication. The article examines the scientific basis for the various decisions needed to formulate a strategy that effectively addresses the problem. Emphasis is placed on the microsurgery of nerve topics: direct nerve repair, autogenous cable nerve grafting, biodegradable conduits, decellularized nerve allograft, and transfer of the anterior interosseous nerve to the ulnar motor branch. The discussion covers the relationship between choices made at the level of the original injury at the cubital tunnel to the timing and selection of distal reconstructive efforts, with specific attention to the distinction between end-to-end anterior interosseous to ulnar motor branch transfer as opposed to the supercharged end-to-side variation of this procedure.

Management and complications of traumatic peripheral nerve injuries

This article provides an overview of the management of traumatic peripheral nerve injuries. It examines the basic pathophysiology of peripheral nerve injuries, along with the clinical presentation, diagnostic work-up, and treatment options and outcomes for the various classifications of traumatic peripheral nerve injuries.

Nerve entrapment: update

LEARNING OBJECTIVES

After reading this article, the participant should be able to: 1. Understand the pathophysiology of chronic nerve compression. 2. Describe the evaluation of a patient presenting with compression neuropathy. 3. Discuss the current controversies in the management of compression neuropathies. 4. Describe the treatment of common compression neuropathies, including carpal and cubital tunnel syndromes.

SUMMARY

Nerve entrapment syndromes are common in the general population, and are managed by a wide variety of medical and surgical specialists. A thorough understanding of the pathophysiology of nerve compression and appropriate clinical workup are critical in the overall management of these conditions. There remain several topics of controversy regarding the surgical management of nerve entrapment syndromes, including multiple points of nerve compression, carpal tunnel release under local anesthesia, open versus endoscopic decompression surgery, the "best" operation for primary cubital tunnel surgery, and revision decompression surgery. This article attempts to provide a concise summary of the advances in the basic and clinical science of peripheral nerve entrapment.

Principles of nerve repair in complex wounds of the upper extremity

Peripheral nerve injuries are common in the setting of complex upper extremity trauma. Early identification of nerve injuries and intervention is critical for maximizing return of function. In this review, the principles of nerve injury, patient evaluation, and surgical management are discussed. An evidence-based approach to nerve reconstruction is reviewed, including the benefits and limitations of direct repair and nerve gap reconstruction with the use of autografts, processed nerve allografts, and conduits. Further, the principles and indications of commonly used nerve transfers in proximal nerve injuries are also addressed.

Rehabilitation of the upper extremity following nerve and tendon reconstruction: when and how

Following upper extremity nerve and tendon reconstruction, rehabilitation is necessary to achieve optimal function and outcome. In this review, the authors present current evidence and literature regarding the strategies and techniques of rehabilitation following peripheral nerve and tendon reconstruction.

Management of ulnar nerve injuries

Injuries to the ulnar nerve result in both sensory and motor deficits within the hand. Functional outcomes following repair of this nerve have not performed as well as outcomes following repair of the median or radial nerves. Advances in imaging modalities may provide earlier means of identifying and diagnosing closed nerve injuries. Early neurorrhaphy of acute nerve injuries provides the best outcome, but consideration should also be given to performing distal motor nerve transfers to preserve hand intrinsic motor function when injuries occur at or above the proximal forearm. This article attempts to summarize the most recent trends within ulnar nerve repair.

Motor and sensory nerve transfers in the forearm and hand

BACKGROUND

Peripheral nerve injury is a significant problem affecting more than 1 million people around the world each year and poses major challenges to the plastic and reconstructive surgeon. For high upper extremity nerve injuries, distal muscle reinnervation and functional outcomes are generally poor. Tendon transfer has been the traditional reconstructive option in these cases to restore hand function. More recently, nerve transfers have been described in the forearm and hand to recover hand and wrist function and critical sensation.

METHODS

This article reviews the surgical principles, donor nerve options, indications, and outcomes of distal nerve transfers for high upper extremity nerve injuries.

RESULTS

The functional results of nerve transfers to date have been comparable to tendon transfers. The primary advantage is the potential for individual finger motion from a donor nerve with singular function. The disadvantage is the longer recovery time required for muscle reinnervation.

CONCLUSIONS

Nerve transfers are a viable option for peripheral nerve injuries distal to the brachial plexus. The choice of management will depend on the patient's individual goals and priorities in terms of the need or desire for individual finger movement and the length of the recovery period.

Advances in nerve transfer surgery

Peripheral nerve injuries are devastating injuries and can result in physical impairments, poor functional outcomes and high levels of disability. Advances in our understanding of peripheral nerve regeneration and nerve topography have lead to the development of nerve transfers to restore function. Over the past two decades, nerve transfers have been performed and modified. With the advancements in surgical management and recognition of importance of cortical plasticity, motor-reeducation and perioperative rehabilitation, nerve transfers are producing improved functional outcomes in patients with nerve injuries. This manuscript explores the recent literature as it relates to current nerve transfer techniques and advances in post-operative rehabilitation protocols, with a focus on indications, techniques and outcomes.

Direct radial to ulnar nerve transfer to restore intrinsic muscle function in combined proximal median and ulnar nerve injury: case report and surgical technique

A distal median to ulnar nerve transfer for timely restoration of critical intrinsic muscle function is possible in isolated ulnar nerve injuries but not for combined ulnar and median nerve injuries. We used a distal nerve transfer to restore ulnar intrinsic function in the case of a proximal combined median and ulnar nerve injury. Transfer of the nonessential radial nerve branches to the abductor pollicis longus, extensor pollicis brevis, and extensor indicis proprius to the motor branch of the ulnar nerve was performed in a direct end-to-end fashion via an interosseous tunnel. This method safely and effectively restored intrinsic function before terminal muscle degeneration.

An anatomical study of transfer of the anterior interosseous nerve for the treatment of proximal ulnar nerve injuries

We conducted an anatomical study to determine the best technique for transfer of the anterior interosseous nerve (AIN) for the treatment of proximal ulnar nerve injuries. The AIN, ulnar nerve, and associated branches were dissected in 24 cadaver arms. The number of branches of the AIN and length available for transfer were measured. The nerve was divided just proximal to its termination in pronator quadratus and transferred to the ulnar nerve through the shortest available route. Separation of the deep and superficial branches of the ulnar nerve by blunt dissection alone, was also assessed. The mean number of AIN branches was 4.8 (3 to 8) and the mean length of the nerve available for transfer was 72 mm (41 to 106). The transferred nerve reached the ulnar nerve most distally when placed dorsal to flexor digitorum profundus (FDP). We therefore conclude that the AIN should be passed dorsal to FDP, and that the deep and superficial branches of the ulnar nerve require approximately 30 mm of blunt dissection and 20 mm of sharp dissection from the point of bifurcation to the site of the anastomosis.

The use of this technique for transfer of the AIN should improve the outcome for patients with proximal ulnar nerve injuries.

Cite this article: Bone Joint J 2014;96-B:789–94.

Nerve gaps

SUMMARY

Peripheral nerve injury is a significant problem affecting greater that 1 million people around the world each year and poses major challenges to the plastic and reconstructive surgeon. When primary nerve repair is not possible, several options for management of the nerve gap include a nerve autograft, nerve conduit, and acellular nerve allograft. For extensive and proximal nerve injuries, cellular nerve allografts and nerve transfers may be considered. This article reviews the indications and outcomes for each option, as in many cases more than one option may be acceptable.

Evidence and techniques in rehabilitation following nerve injuries

Following upper extremity peripheral nerve injury and surgery, rehabilitation is essential to optimize sensorimotor function and outcome. This review presents the evidence and related literature regarding a few key topics related to rehabilitation following peripheral nerve injury and surgery.

Functional recovery of severe obturator and femoral nerve injuries after lateral retroperitoneal transpsoas surgery

The minimally invasive lateral retroperitoneal transpsoas approach is a popular fusion technique. However, potential complications include injury to the lumbar plexus nerves, bowel, and vasculature, the most common of which are injuries to the lumbar plexus. The femoral nerve is particularly vulnerable because of its size and location; injury to the femoral nerve has significant clinical implications because of its extensive sensory and motor innervation of the lower extremities. The authors present an interesting case of a 49-year-old male patient in whom femoral and obturator nerve functional recovery unexpectedly occurred 364 days after the nerves had been injured during lateral retroperitoneal transpsoas surgery. Chronological video and electrodiagnostic findings demonstrate evidence of recovery. Classification and mechanisms of nerve injury and nerve regeneration are discussed.