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Background: With ulnar nerve injuries, paralysis of the first dorsal interosseous and adductor pollicis muscle weakens the patient's pinch. In the palm, we transferred the opponens pollicis motor branch to the deep terminal division of the ulnar nerve for pinch reconstruction., Methods: Sixteen patients with ulnar nerve injuries around the elbow underwent reconstruction and were followed up postoperatively for a minimum of 14 months. Their mean age was 41 ± 16 years, and the mean interval between injury and surgery was 134 ± 126 days (range, 2 to 390 days). Preoperatively and postoperatively, grasp, key, and subterminal key pinch strength were measured using dynamometers., Results: Reinnervation of the first dorsal interosseous muscle was observed in 15 of the 16 patients. Mean grasp strength improved from 15.5 ± 8.5 kg preoperatively to 24 ± 10 kg postoperatively, achieving 57% ± 16% of contralateral hand strength. Preoperatively, terminal key pinch averaged 3 ± 1 kg, which improved postoperatively to 5.5 ± 2 kg, achieving 71 ± 24% of the strength measured contralaterally. Preoperatively to postoperatively, subterminal key pinch force increased from 0 to 2.4 ± 1.3 kg, achieving 61% ± 27% that of the unaffected side. Patients who underwent surgery within 6 months of their injury showed a mean subterminal key pinch strength recovery of 63% ± 27% of the normal side, whereas those who underwent surgery between 7 and 13 months after injury showed a mean subterminal key pinch strength recovery of 51% ± 29%., Conclusion: Transferring the opponens pollicis motor branch to the deep terminal division of the ulnar nerve improved pinch and grasp strength without jeopardizing thumb function., Clinical Question/level of Evidence: Therapeutic, IV., (Copyright © 2023 by the American Society of Plastic Surgeons.)

The supercharge end-to-side anterior interosseous to ulnar motor nerve transfer has gained popularity over the past decade as a method of augmenting intrinsic muscle reinnervation in patients with acute neurotmetic ulnar nerve injuries. Controversy remains regarding its efficacy and appropriate clinical indications in cubital tunnel syndrome, where the timing of onset of axonal loss is less clear. The authors present guidelines for patient selection, surgical technique, and postoperative rehabilitation based on their clinical experience with the technique in this patient population. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Therapeutic, V.

Background: Elbow flexion after upper brachial plexus injury may be restored by a nerve transfer from the ulnar nerve to the biceps motor branch with an optional nerve transfer from the median nerve to the brachialis motor branch (single and double fascicular nerve transfer). This meta-analysis assesses the effectiveness of both techniques and the added value of additional reinnervation of the brachialis muscle., Methods: Comprehensive searches were performed identifying studies concerning restoration of elbow flexion through single and double fascicular nerve transfers. Only C5 to C6 lesion patients were included in quantitative analysis to prevent confounding by indication. Primary outcome was the proportion of patients reaching British Medical Research Council elbow flexion grade 3 or greater. Meta-analysis was performed with random effects models., Results: Thirty-five studies were included (n = 688). In quantitative analysis, 29 studies were included (n = 341). After single fascicular nerve transfer, 190 of 207 patients reached Medical Research Council grade 3 or higher (random effects model, 95.6 percent; 95 percent CI, 92.9 to 98.2 percent); and after double fascicular nerve transfer, 128 of 134 patients reached grade 3 or higher (random effects model, 97.5 percent; 95 percent CI, 95.0 to 100 percent; p = 0.301). Significantly more double nerve transfer patients reached grade 4 or greater if preoperative delay was 6 months or less (84 of 101 versus 49 of 51; p = 0.035)., Conclusions: Additional reinnervation of the brachialis muscle did not result in significantly more patients reaching Medical Research Council grade 3 or higher for elbow flexion. Double fascicular nerve transfer may result in more patients reaching grade 4 or higher in patients with a preoperative delay less than 6 months. The median nerve may be preserved or used for another nerve transfer without substantially impairing elbow flexion restoration.

Background: Nerve transfer surgery has revolutionized the management of traumatic brachial plexus injures. However, the optimal size ratio of donor to recipient nerve has yet to be elucidated. The authors investigated the axon count ratios of ulnar and median fascicular transfers to restore elbow flexion. The authors hypothesized that donor nerve axon counts would be correlated with historical success of various nerve transfers used to restore elbow flexion., Methods: Ten cadaveric specimens were used for a histomorphologic analysis of fascicular nerve transfers. Review of previously published axon counts and clinical results following transfer to the musculocutaneous nerve to restore elbow flexion was performed for the following donor nerves: medial pectoral, spinal accessory, intercostal, thoracodorsal, ulnar, and median fascicular., Results: The average number of fascicles identified was 7.9 in the ulnar nerve and 8.0 in the median nerve. The mean fascicular axon count was 1318 for the ulnar nerve and 1860 for the median nerve. Mean recipient nerve axon count was 1826 for the musculocutaneous biceps branch and 1840 for the brachialis branch. A significant correlation between axon count and clinical results of transfers to restore elbow flexion was observed. Donor-to-recipient nerve axon count ratios below 0.7:1 were associated with a decreased likelihood of a successful outcome., Conclusions: In nerve transfers to restore elbow flexion, an appropriate size match between donor and recipient nerves appears to be a factor affecting clinical success. These data support a donor-to-recipient axon count ratio greater than 0.7:1 as the goal for brachial plexus nerve transfers to restore elbow flexion.

Background: Current surgical management of obstetrical brachial plexus injury is primary reconstruction with sural nerve grafts. Recently, the nerve-to-nerve transfer technique has been used to treat brachial plexus injury in adults, affording the benefit of distal coaptations that minimize regenerative distance. The purpose of this study was to test the hypothesis that nerve transfers are effective in reconstructing isolated upper trunk obstetrical brachial plexus injuries., Methods: Ten patients aged 10 to 18 months were treated with three nerve transfers: spinal accessory nerve to the suprascapular nerve for shoulder abduction and external rotation; a radial to axillary nerve for shoulder abduction; and ulnar or median nerve transfer to the musculocutaneous nerve for elbow flexion. Patients were assessed preoperatively and postoperatively using the Active Movement Scale. All patients were followed regularly for up to 2 years., Results: Improvement in elbow and shoulder function was observed between 6 and 24 months. By 6 months, all patients passed the cookie test. At 24 months, shoulder abduction improved from 3.7 ± 0.6 to 5.0 ± 0.5, shoulder external rotation from 1.8 ± 0.4 to 4.3 ± 0.6, shoulder flexion from 3.7 ± 0.5 to 5.4 ± 0.5, elbow flexion from 3.7 ± 0.6 to 6.3 ± 0.2, and forearm supination from 2.1 ± 0.4 to 5.9 ± 0.2. There was no clinically appreciable donor-site morbidity., Conclusions: Nerve transfers reduced operative times compared with traditional nerve grafting procedures. Those patients showed significant gains in Active Movement Scale score by 24 months postoperatively, comparable to results achieved by nerve grafting. These findings support nerve transfers as a potential alternative treatment option for upper trunk obstetrical brachial plexus injuries., Clinical Question/level of Evidence: Therapeutic, IV.

Background: Vascularized nerve grafts were introduced in 1976. Subsequent studies have suggested the superiority of vascularized nerve grafts. In this study, the authors present 23 years' experience with vascularized ulnar nerve graft. The factors influencing outcomes and a comparison with conventional nerve grafts are presented., Methods: Between 1981 and 2003, 151 reconstructions with ulnar nerve were performed in 67 patients for brachial plexus injuries. Patients were divided into four groups: those with vascularized ulnar nerve graft from ipsilateral donors, pedicled or free, and those with vascularized ulnar nerve graft from contralateral donors to median nerve or to single motor targets (e.g., axillary, musculocutaneous, triceps) (n = 25, 21, 13, and 8, respectively)., Results: Patients with long denervation times yielded inferior results compared with those operated on early. Pedicle and free ipsilateral ulnar nerve grafts yielded comparable results for biceps muscle neurotization. Neurotization of biceps with a vascularized ulnar nerve graft from the contralateral root was not as effective as neurotization from ipsilateral donors. There was a difference in muscle grading when the target was the median nerve versus single motor targets such as axillary, musculocutaneous, or triceps, but there were no differences between preoperative and postoperative muscle grading of median innervated muscles., Conclusions: Vascularized ulnar nerve grafting is the appropriate solution for brachial plexus injuries with C8 and T1 root avulsion, with outcomes that are superior to those achieved with conventional nerve grafts. Although few changes have been made over time, the use of ulnar nerve grafts for neurotization of multiple motor targets of the median nerve from contralateral donors is under consideration.

Background: The Rho family of small GTPases is responsible for various processes involving actin cytoskeleton in eukaryotic cells, including neurite outgrowth. Several substances found at the peripheral nerve injury site were shown to activate one member of this family, Rho. The activation of Rho leads to neurite outgrowth inhibition and the development of posttraumatic neuropathic pain. The authors used the clinically tested Rho-associated kinase inhibitor fasudil hydrochloride to enhance the functional recovery of the peripheral nerve in the rat., Methods: In the peroneal nerve interpositional graft model, the authors administered fasudil (experimental groups) or saline (control groups) (1) intraperitoneally and (2) directly into the graft by microinjection (n = 6 animals per experimental condition). Neural recovery was assessed during postoperative follow-up lasting 80 days by peroneal functional index, electrophysiologic, and histomorphometric analyses., Results: The peroneal functional index returned to values not significantly different from preoperative values on days 55 (fasudil injected into the graft) and 60 (fasudil injected intraperitoneally) in the experimental groups. In the control groups, this took 70 (saline injected intraperitoneally) and 75 days (saline injected into the graft). These results are supported by electrophysiologic and histomorphologic assessments., Conclusions: The authors determined that fasudil hydrochloride was capable of accelerating the functional regeneration after peripheral nerve axotomy, which is consistent with the results of reports about Rho cascade disruption in the central nervous system. Because fasudil hydrochloride is a clinically tested drug, it could be used to enhance neural regeneration in human patients as well.

Background: Limitations in autogenous tissue have inspired the study of alternative materials for repair of complex peripheral nerve injuries. Cadaveric allografts are one potential reconstructive material, but their use requires systemic immunosuppression. Cold preservation (> or =7 weeks) renders allografts devoid of antigens, but these acellular substrates generally fail in supporting regeneration beyond 3 cm. In this study, the authors evaluated the reconstruction of extensive nonhuman primate peripheral nerve defects using 7-week cold-preserved allografts repopulated with cultured autologous Schwann cells., Methods: Ten outbred Macaca fascicularis primates were paired based on maximal genetic disparity as measured by similarity index assay. A total of 14 ulnar nerve defects measuring 6 cm were successfully reconstructed using autografts (n = 5), fresh allografts (n = 2), cold-preserved allografts (n = 3), or cold-preserved allografts seeded with autogenous Schwann cells (n = 4). Recipient immunoreactivity was evaluated by means of enzyme-linked immunosorbent spot assay, and nerves were harvested at 6 months for histologic and histomorphometric analysis., Results: Cytokine production in response to cold-preserved allografts and cold-preserved allografts seeded with autologous Schwann cells was similar to that observed for autografts. Schwann cell-repopulated cold-preserved grafts demonstrated significantly enhanced fiber counts, nerve density, and percentage nerve (p < 0.05) compared with unseeded cold-preserved grafts at 6 months after reconstruction., Conclusions: Cold-preserved allografts seeded with autologous Schwann cells were well-tolerated in unrelated recipients and supported significant regeneration across 6-cm peripheral nerve defects. Use of cold-preserved allogeneic nerve tissue supplemented with autogenous Schwann cells poses a potentially safe and effective alternative to the use of autologous tissue in the reconstruction of extensive nerve injuries.

Reconstruction of shoulder stability and movement in cases with complete paralysis of the brachial plexus was performed to improve the outcomes for universal function of prehension after double free-muscle transfer (Doi's procedure). In cases in which the C5 or C6 nerve root was available as a donor, neurotization of the supra-scapular nerve was performed with a nerve graft. If the C5 or C6 nerve root was not available, then the contralateral C7 nerve root was chosen as the donor motor nerve and was transferred to the suprascapular nerve by using a vascularized ulnar nerve graft. Seven cases with ipsilateral C4, C5, or C6 nerve root transfer to the suprascapular nerve and one with contralateral C7 transfer were evaluated, and the functional outcomes for the range of shoulder motion were compared with those for patients who had undergone arthrodesis of the humeroscapular joint or had undergone no procedures for shoulder function reconstruction. The patients who underwent supra-scapular nerve repair demonstrated statistically significantly better ranges of motion for flexion and abduction of the shoulder, compared with the other two groups. Shoulder function is important for achieving prehensile function among patients with complete paralysis of brachial function, when they undergo double free-muscle transfer.

The number of donor nerves available for nerve transfer in the reconstruction of total root avulsion injuries of the brachial plexus is always insufficient. Use of the contralateral normal C7 cervical nerve as a donor nerve is a new approach to obtain more nerve fibers but also is a controversial procedure. Fifteen patients with total root avulsion of the brachial plexus received cross-chest C7 nerve grafting as the first stage of reconstruction. Eight of these patients, after an interval of 11 to 20 months, had free muscle transplantations (one to three muscles transferred per individual) to the affected limb. A long period of rehabilitation (at least 2 years) is required. The donor limbs of the 15 patients showed negligible deficits of motor and sensory function. Although independent movement of the transferred muscles from the contralateral limb has not been achieved, useful function of the reconstructed limb is possible. The preliminary results are encouraging.

The use of articular branch of the dorsal sensory ulnar nerve as a nerve graft is discussed. A case of traumatic neuroma of the dorsal ulnar nerve which was treated by this method is presented.