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

Tendon Transfers, Nerve Grafts, and Nerve Transfers for Isolated Radial Nerve Palsy: A Systematic Review and Analysis

BACKGROUND

Isolated radial nerve palsy is a debilitating injury that may potentially be reconstructed with either tendon transfers, nerve grafts, or nerve transfers. Currently, there is no consensus on the optimal technique for reconstruction. We performed a systematic review and analysis to determine which surgical intervention provides the best clinical outcomes.

METHODS

A systematic review was conducted according to PRISMA guidelines. Twenty-nine papers met inclusion criteria. Grading scales of function and strength were converted into a tripartite scoring system to compare outcomes between techniques. χ2 analyses were performed with a P value < .05.

RESULTS

Seven hundred fifty-four patients were analyzed. Tendon transfers resulted in the highest percentage of good outcomes (82%) and the lowest percentage of poor outcomes (9%). Tendon transfers were superior to nerve grafts and nerve transfers for restoration of wrist extension. Nerve transfers for wrist extension were superior to nerve transfers for finger extension. Nerve grafts and nerve transfers had equivalent rates of good and poor clinical outcomes.

CONCLUSIONS

This study analyzed reported outcomes of tendon transfers, nerve grafts, and nerve transfers for reconstruction of isolated radial nerve palsy. On pooled analysis, tendon transfers had higher rates of superior clinical outcomes as compared with nerve transfers and nerve grafts. Tendon transfers should be considered first-line reconstruction for isolated radial nerve palsy as nerve-based reconstruction is less predictable and reproducible.

The comparative efficacy of nerve transfer versus tendon transfer in the management of radial palsy: A systematic review and meta-analysis

Background

There is no clear census as to which operative technique provides better recovery for radial nerve injuries. Therefore, in this systematic review, we examined the functional recovery, patient-reported outcomes, and complications of tendon transfer (TT) and nerve transfer (NT).

Methods

Five electronic databases were searched for studies (>10 cases per study) comparing NT and TT regardless of the study design (observational or experimental). Manual search was also conducted. The quality was assessed by the NIH tool. Outcomes included functional recovery, patient-reported outcomes (DASH score, satisfaction, and inability to return to work), and complications. The prevalence was pooled across studies using STATA software, and then, a subgroup analysis based on the intervention type.

Results

Twenty-one studies (542 patients) were analyzed. Excellent recovery, assessed by the Bincaz scale, was higher in the TT group (29 % vs. 11 %) as well as failure to extend the fingers (49 % vs. 9 %). No significant difference was noted between both groups regarding DASH score (mean difference = -2.76; 95 % CI: -12.66: 6.93). Satisfaction was great in the TT group (89 %) with a limited proportion of patients unable to return to work (7 %). Complications were slightly higher in the TT group (8 % vs. 7 %) while 18 % of patients undergoing TT requiring revision surgery. Radial deviation was encountered in 18 % of patients in the TT group and 0 % in the NT group. The quality was good, fair, and poor in 2, 13, and 6, respectively.

Conclusions

In radial nerve injuries, although tendon transfer may seem to provide better functional motor recovery than nerve transfer, it is associated with a higher rate of failure to extend the finger. Given the large confidence interval, the accuracy of this finding is questioned. However, a great proportion of those patients require revision surgery afterward. Additionally, tendon transfer is associated with a greater complication rate than nerve transfer, particularly radial deviation.

Elevated Body Mass Index Negatively Impacts Recovery of Shoulder Abduction Strength in Triceps Motor Branch to Axillary Nerve Transfers

BACKGROUND

The purpose of this work was to evaluate the clinical outcomes of triceps motor branch to axillary nerve transfers and to identify prognostic factors which may influence these outcomes.

METHODS

A retrospective cohort included all patients who underwent a triceps motor branch to axillary nerve transfer (2010-2019) with at least 12 months of follow-up. The primary outcome measure was shoulder abduction strength assessed with British Medical Research Council (MRC) grade.

RESULTS

Ten patients were included with a mean follow-up of 19.1 (SD 5.9) months. Compared with preoperative MRC shoulder abduction strength (0.2 SD 0.4), patients significantly improved postoperatively (2.8 SD 1.6; P = .005). Increased body mass index (BMI) was significantly associated with worse postoperative MRC (P = .014).

CONCLUSION

Triceps motor branch to axillary nerve transfer is a beneficial procedure for restoring shoulder function in patients presenting with either isolated axillary nerve or brachial plexus pathology. Patients with elevated BMI may not have as robust strength recovery and should be counseled carefully regarding prognosis.

Pronator teres nerve branch transfer to the extensor carpi radialis brevis nerve branch for wrist extension reconstruction in proximal radial nerve injury following humeral shaft fractures

Background

Tendon and nerve transfers are used for functional reconstruction in cases of proximal radial nerve injury complicated by humeral fractures in patients who do not show functional recovery after primary nerve repair. The effectiveness of pronator teres (PT) nerve branch transfer to the extensor carpi radialis brevis (ERCB) nerve branch for wrist extension reconstruction was investigated and compared to the results of tendon transfer.

Methods

This study included 10 patients with proximal radial nerve injury, who did not show functional recovery after primary nerve repair at our hospital between April 2016 and May 2019. The nerve transfer procedure included PT nerve branch transfer to the ECRB nerve branch to restore wrist extension and the flexor carpi radialis (FCR) nerve branch to the posterior interosseous nerve (PIN) to restore thumb and finger extension. Tendon transfer procedures included PT transfer to the ECRB for wrist extension, FCR transfer to the extensor digitorum communis (EDC) for finger extension and palmaris longus (PL) transfer to the extensor pollicis longus (EPL) for thumb extension.

Results

Five patients recovered Medical Research Council grade M4 muscle strength in the ECRB and EPL in both tendon and nerve groups. Two patients recovered grade M3 strength and three patients recovered grade M4 strength in the EDC in the tendon transfer group, and all five patients recovered grade M4 strength in the EDC in the nerve transfer group. Limited wrist flexion was observed only in one patient in the tendon transfer group.

Conclusion

PT nerve branch transfer to the ECRB nerve branch combined with FCR nerve branch transfer to PIN is a useful strategy for wrist and fingers extension reconstruction in patients with proximal radial nerve injuries.

Nerve transfers in the forearm: potential use in spastic conditions

PURPOSE

Deformities of the spastic upper limb result frequently from the association of spasticity, muscle contracture and muscle imbalance between strong spastic muscles and weak non-spastic muscles. This study was designed to evaluate the feasibility of combining selective neurectomy of the usual spastic and strong muscles together with transfer of their motor nerves to the usual weak muscles, to improve wrist and fingers motion while decreasing spasticity.

METHODS

Twenty upper limbs from fresh frozen human cadavers were dissected. All motor branches of the radial and median nerve for the forearm muscles were identified. We attempted all possible end-to-end nerve transfers between the usually strong "donor" motor branches, namely FCR and PT, and the usually weak "recipient" motor branches (ERCL, ECRB, PIN, AIN).

RESULTS

 The PT had two nerve branches in 80%, thus allowing selective neurectomy. The proximal PT branch could be anastomosed end-to-end in 45% (AIN) to 85% (ECRL) of cases with the potential recipient branches. The distal PT branch could be anastomosed end to end to all potential recipient nerves. The FCR had a single branch in all cases. End-to-end anastomosis was possible in 90% for the ECRL and in 100% for all other recipient branches, but sacrificed all FCR innervation, ruling out hyperselective neurectomy.

CONCLUSION

 Selective neurectomies can be associated with distal nerve transfers at the forearm level in selected cases. The motor nerve to the PT is the best donor for nerve transfer combined with selective neurectomy, transferred to the ECRL, ECRB, PIN or AIN.

Autologous Fibrin Glue Versus Microsuture in the Surgical Reconstruction of Peripheral Nerves: A Randomized Clinical Trial

PURPOSE

This study compared the motor and sensory recovery and the operative time of autologous fibrin glue application with conventional microsuturing technique in repairing peripheral nerves at the forearm and wrist levels METHODS: Eighty-five patients with injuries of the median, ulnar, or both nerves at the wrist and forearm levels underwent nerve repair between September 2014 and June 2018. Patients were randomly assigned at the time of diagnosis to a microsuture group (42 patients), in which standard epineurial microsurgical suturing was performed, or a fibrin glue group (43 patients), in which nerve repair was performed using autologous fibrin glue. The primary outcome measure was motor and sensory recovery. Operative time was the secondary outcome measure. Other outcome measures that were added post hoc, after trial initiation, included time to motor and sensory recovery; grip strength; pinch strength; Michigan hand outcome score; amplitude, latency, and duration of the compound motor unit action potential; and complications. All patients were followed up a minimum of 1 year.

RESULTS

At the final follow-up, both groups had regained similar motor and sensory function. The mean operative time was shorter in the fibrin glue group. Both groups had similar amplitude, latency, and duration of the compound motor unit action potential. Michigan Hand Outcome scores and mean percent recovery of grip strength and pinch strength were also similar. Six of 43 patients in the fibrin glue group compared with 8 of 42 patients in the microsuture group developed postoperative complications.

CONCLUSIONS

The use of fibrin glue to repair peripheral nerves is as effective as microsuturing in regaining motor and sensory functions and is associated with shorter operative time.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic II.

Patterns of median nerve branching in the cubital fossa: implications for nerve transfers to restore motor function in a paralyzed upper limb

OBJECTIVE

The purpose of this study was to describe the anatomy of donor and recipient median nerve motor branches for nerve transfer surgery within the cubital fossa.

METHODS

Bilateral upper limbs of 10 fresh cadavers were dissected after dyed latex was injected into the axillary artery.

RESULTS

In the cubital fossa, the first branch was always the proximal branch of the pronator teres (PPT), whereas the last one was the anterior interosseous nerve (AIN) and the distal motor branch of the flexor digitorum superficialis (DFDS) on a consistent basis. The PT muscle was also innervated by a distal branch (DPT), which emerged from the anterior side of the median nerve and provided innervation to its deep head. The palmaris longus (PL) motor branch was always the second branch after the PPT, emerging as a single branch together with the flexor carpi radialis (FCR) or the proximal branch of the flexor digitorum superficialis. The FCR motor branch was prone to variations. It originated proximally with the PL branch (35%) or distally with the AIN (35%), and less frequently from the DPT. In 40% of dissections, the FDS was innervated by a single branch (i.e., the DFDS) originating close to the AIN. In 60% of cases, a proximal branch originated together with the PL or FCR. The AIN emerged from the posterior side of the median nerve and had a diameter of 2.3 mm, twice that of other branches. When dissections were performed between the PT and FCR muscles at the FDS arcade, we observed the AIN lying lateral and the DFDS medial to the median nerve. After crossing the FDS arcade, the AIN divided into: 1) a lateral branch to the flexor pollicis longus (FPL), which bifurcated to reach the anterior and posterior surfaces of the FPL; 2) a medial branch, which bifurcated to reach the flexor digitorum profundus (FDP); and 3) a long middle branch to the pronator quadratus. The average numbers of myelinated fibers within each median nerve branch were as follows (values expressed as the mean ± SD): PPT 646 ± 249; DPT 599 ± 150; PL 259 ± 105; FCR 541 ± 199; proximal FDS 435 ± 158; DFDS 376 ± 150; FPL 480 ± 309; first branch to the FDP 397 ± 12; and second branch to the FDP 369 ± 33.

CONCLUSIONS

The median nerve's branching pattern in the cubital fossa is predictable. The most important variation involves the FCR motor branch. These anatomical findings aid during nerve transfer surgery to restore function when paralysis results from injury to the radial or median nerves, brachial plexus, or spinal cord.

Foot Reanimation Using Double Nerve Transfer to Deep Peroneal Nerve: A Novel Technique for Treatment of Neurologic Foot Drop

BACKGROUND

Our primary objective was to assess the efficacy of a new technique for foot reanimation in patients with neurologic foot drop using double nerve transfer from the tibial to the deep peroneal nerve. Our secondary objective was to document the technical nuances of our technique.

METHODS

Thirty-one patients with common peroneal nerve injury between October 2015 and March 2019 were prospectively enrolled in the study. Patients underwent a transfer of the tibial nerve branches to flexor digitorum longus and lateral head of gastrocnemius to the deep peroneal nerve. Motor recovery, range of ankle dorsiflexion, pain, leg girth, and complications were examined as outcome measures. The modified Medical Research Council (MRC) scale was adopted to assess the motor power recovery. All patients were followed up for a minimum of 1 year.

RESULTS

Motor recovery of M3 or M4 grade of tibialis anterior, extensor hallucis longus, and extensor digitorum longus was achieved in 15 of 31, 13 of 31, and 12 of 31 patients, respectively. Those patients could discontinue use of orthosis. Most patients with high-energy traumas or knee-level injuries failed to recover antigravity function. Only 2 patients reported weak postoperative toe plantarflexion. Our patients achieved significant improvement of the pain perception and range of active ankle motion at the final follow-up.

CONCLUSION

The double nerve transfer technique represented a feasible and safe surgical option. It has been shown to improve function in some patients with neurologic foot drop resulting from a less than 12-month injury of the deep peroneal nerve.

LEVEL OF EVIDENCE

Level IV, therapeutic.

Effectiveness of Distal Nerve Transfers for Claw Correction With Proximal Ulnar Nerve Lesions

PURPOSE

To evaluate claw deformity correction following anterior interosseous nerve (AIN) end-to-end transfer to the deep motor branch of the ulnar nerve (DMBUN) in high ulnar nerve injuries.

METHODS

Eleven patients were retrospectively evaluated for metacarpophalangeal joint hyperextension and proximal interphalangeal joint extension lag in the fourth and fifth digits following ulnar nerve injury adjacent or proximal to the elbow, who underwent AIN end-to-end transfer to the DMBUN.

RESULTS

Patients underwent surgery an average of 5 months following injury (range, 2-9 months) and were followed for an average of 19 months after surgery (range, 12-30 months). At the last follow-up, clawing was observed in all patients, with proximal interphalangeal joint extension lag averaging 46.8° (SD, ±20°) in the fourth digit and 57.7° (SD, ±12°) in the little finger.

CONCLUSIONS

None of our patients experienced claw correction after AIN end-to-end transfer to the DMBUN.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Impact of Body Mass Index and Comorbidities on Outcomes in Upper Extremity Nerve Transfers

BACKGROUND

 There is a paucity of research investigating the impact of patient comorbidities, such as obesity and smoking, on nerve transfer outcomes. The objective of this retrospective cohort study was to evaluate the impact of body mass index (BMI) and comorbidities on the clinical outcomes of upper extremity nerve transfers.

METHODS

 A retrospective cohort study was executed. Patients were eligible for inclusion if they had an upper extremity nerve transfer with a minimum of 12-months follow-up. Data was collected regarding demographics, comorbidities, injury etiology, nerve transfer, as well as preoperative and postoperative clinical assessments. The primary outcome measure was strength of the recipient nerve innervated musculature. Statistical analysis used the Mann-Whitney U test, Wilcoxon signed-rank test, and Spearman's rho.

RESULTS

 Thirty-eight patients undergoing 43 nerve transfers were eligible for inclusion. Patients had a mean age of 48.8 years and a mean BMI of 27.4 kg/m² (range:19.7-39.0). Injuries involved the brachial plexus (32%) or its terminal branches (68%) with the most common etiologies including trauma (50%) and compression (26%). Anterior interosseous nerve to ulnar motor nerve (35%) was the most common transfer performed. With a mean follow-up of 20.1 months, increased BMI (p = 0.036) and smoking (p = 0.021) were associated with worse postoperative strength.

CONCLUSION

 This retrospective cohort study demonstrated that increased BMI and smoking may be associated with worse outcomes in upper extremity nerve transfers-review of the literature yields ambiguity in both regards. To facilitate appropriate patient selection and guide expectations regarding prognosis, further experimental and clinical work is warranted.

Transfer of the Distal Anterior Interosseous Nerve for Thumb Motion Reconstruction in Radial Nerve Paralysis

PURPOSE

With nerve or tendon surgery, the results of thumb reconstruction to treat radial nerve paralysis are suboptimal. The goals of this study were to describe the anatomy of the deep branch of the posterior interosseous nerve (PIN) to the thumb extensor muscles (DBPIN), and to report the clinical results of transferring the distal anterior interosseous nerve (DAIN) to the DBPIN.

METHODS

The PIN was dissected in 12 fresh upper limbs. Myelinated nerve fibers in the DBPIN and DAIN were counted. Five patients with radial nerve paralysis underwent transfer of the motor branch to the flexor carpi radialis to the PIN and a motor branch of the pronator teres to the extensor carpi radialis brevis. In addition, these patients had selective reconstruction of thumb motion by transferring the DAIN to the DBPIN, through either a combined volar and dorsal approach (n = 2) or a single dorsal approach (n = 3) with division of the interosseous membrane.

RESULTS

At the origin of the abductor pollicis longus, the DBPIN divided into a lateral branch that innervated the abductor pollicis longus and extensor pollicis brevis, and a medial branch that innervated the extensor pollicis longus and extensor index proprius. The number of myelinated nerve fibers in the DAIN corresponded to 65% of that of the DBPIN. In each of the 5 patients, full thumb motion at the trapeziometacarpal joint was restored with no, or minimal, extension lag at the metacarpophalangeal (MCP) joint.

CONCLUSIONS

The anatomy of the DBPIN is predictable. Transferring the DAIN to the DBPIN is feasible through a single dorsal approach, allowing full recovery of thumb motion.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

Nerve Versus Tendon Transfer for Radial Nerve Paralysis Reconstruction

PURPOSE

With radial nerve lesions, the results of nerve transfers and how they objectively compare with the outcomes of tendon transfers remain unstudied. We compared the results after nerve transfer in patients with less than 12 months since radial nerve injury with the results after tendon transfer in patients not eligible for nerve surgery because of longstanding paralysis (minimum of 15 months).

METHODS

In 14 patients with radial nerve lesions incurred less than 12 months previously, we transferred the anterior interosseous nerve to the nerve of the extensor carpi radialis brevis (ECRB), while the nerve to the flexor carpi radialis was transferred to the posterior interosseous nerve. In 13 patients with lesions of longer duration, we transferred the pronator teres tendon to the ECRB, the flexor carpi ulnaris tendon to the extensor digitorum communis, and the palmaris longus to the rerouted extensor pollicis longus (EPL) tendon. At a final evaluation, we measured passive and active range of motion (ROM) of the wrist, finger, and thumb and grasp strength.

RESULTS

In a comparison of wrist flexion-extension ROM and grasp strength, we observed better recovery in the nerve transfer than in the tendon transfer group. In the tendon transfer group, we observed limitations in wrist flexion in 9 of the 13 patients and permanent radial deviation in 5. Half of the patients in the tendon transfer group needed to flex their wrist to fully extend their fingers, whereas finger extension was possible with the wrist either extended or at neutral in all patients following nerve transfer. After nerve transfer, extension at the first carpometacarpal joint was restored in 11 of the 14 patients, whereas this occurred in just 4 of the 13 patients following tendon transfer. In both groups, we observed a 30° lag in thumb metacarpophalangeal extension, which reflects poor recovery of EPL function.

CONCLUSIONS

Overall, we observed better outcomes in those who underwent nerve transfer versus tendon transfer procedures. However, room still remains for improved thumb motion with both procedures.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

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.

Nerve and Free Gracilis Muscle Transfers for Thumb and Finger Extension Reconstruction in Long-standing Tetraplegia

PURPOSE

With spinal cord injuries, muscles below the level of the lesion remain innervated despite the absence of volitional control. This persistent innervation protects against denervation atrophy and may allow for nerve transfers to treat long-standing lesions within the spinal cord. We tested the hypothesis that in chronic spinal cord lesions, muscles remained viable for reinnervation.

METHODS

To test this hypothesis, we operated on 7 patients with tetraplegia to reconstruct thumb and finger extension after a mean interval of 5 years since injury. During surgery, if electrical stimulation of the posterior interosseous nerve (PIN) produced muscle contraction, the nerve to the supinator (NS) was transferred to the PIN. If no contractions were demonstrated, the muscles of the extensor compartment of the forearm were replaced via a free gracilis transfer with innervation supplied by the NS.

RESULTS

After an average of 26 months, M3 recovery of thumb and finger extension was observed in the 3 upper limbs from the 2 youngest patients who underwent a nerve transfer. None of the free gracilis-treated patients achieved scores above M2.

CONCLUSIONS

In our youngest patients aged 27 and 34 years, who were operated on 6 years after spinal cord injury, transfer of the NS to the PIN partially restored hand span.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.