Outcomes of Tibial Nerve Repair and Transfer: A Structured Evidence-Based Systematic Review and Meta-Analysis

Assessment, patient selection, and rehabilitation of nerve transfers

Peripheral nerve injuries are common and can have a devastating effect on physical, psychological, and socioeconomic wellbeing. Peripheral nerve transfers have become the standard of care for many types of peripheral nerve injury due to their superior outcomes relative to conventional techniques. As the indications for, and use of, nerve transfers expand, the importance of pre-operative assessment and post-operative optimization increases. There are two principal advantages of nerve transfers: (1) their ability to shorten the time to reinnervation of muscles undergoing denervation because of peripheral nerve injury; and (2) their specificity in ensuring proximal motor and sensory axons are directed towards appropriate motor and sensory targets. Compared to conventional nerve grafting, nerve transfers offer opportunities to reinnervate muscles affected by cervical spinal cord injury and to augment natural reinnervation potential for very proximal injuries. This article provides a narrative review of the current scientific knowledge and clinical understanding of nerve transfers including peripheral nerve injury assessment and pre- and post-operative electrodiagnostic testing, adjuvant therapies, and post-operative rehabilitation for optimizing nerve transfer outcomes.

Following a Surgical Paradigm Shift Through the Adoption of Nerve Transfers Among Board-Eligible and Practicing Plastic Surgeons

BACKGROUND

Nerve transfers represent a new paradigm in the treatment of nerve injuries. Their current level of adoption among surgeons is unknown. This study evaluates the incidence of nerve transfers on case logs of board-eligible plastic surgeons over the past 14 years and surveys practicing nerve surgeons regarding their use of this technique.

METHODS

We queried the American Board of Plastic Surgery case log database for all nerve reconstruction Current Procedural Terminology codes from 2008 to 2021 and assessed trends and relationships between geographic region, examination year, and nerve transfer use. We surveyed nerve surgery professional societies to assess trends in practice, compared with a 2017 survey.

RESULTS

A total of 1959 nerve reconstruction cases were logged by 738 candidates from 2008 to 2021. Twelve percent of cases included nerve transfers. The proportion of nerve transfer codes (Z = -11.57; P < .0001) and the proportion of candidates performing nerve transfers (Z = -9.21, P < .0001) increased over the study period. Nerve transfers were associated with geographic region (χ² = 25.826, P = .0002), with most cases performed in the Midwest (26.4%). A higher proportion of practicing nerve surgeons reported performing nerve transfers in this survey than in our 2017 survey (χ² = 16.7, P < .001).

CONCLUSIONS

There has been an increase in nerve transfers logged in the past 14 years by board-eligible plastic surgeons, as well as increased use among currently practicing nerve surgeons. Although nerve transfer use is increasing among both plastic and orthopedic surgeons, a greater proportion of nerve reconstructions include nerve transfers in the plastic surgery cohort.

Functional Muscle Transfer after Oncologic Extremity Resection

BACKGROUND

 Functional muscle transfer (FMT) can provide wound closure and restore adequate muscle function for patients with oncologic extremity defects. Herein we describe our institutional experience with FMT after oncological resection and provide a systematic review and meta-analysis of the available literature on this uncommon procedure.

METHODS

 A single-institution retrospective review was performed, including all patients who received FMT after oncological resection from 2005 to 2021. For the systematic review and meta-analysis, PubMed, Cochrane, Medline, and Embase libraries were queried according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines; results were pooled, weighted by study size, and analyzed.

RESULTS

 The meta-analysis consisted of seven studies with 70 patients overall, demonstrating a mean Medical Research Council (MRC) score of 3.78 (95% confidence interval: 2.97-4.56; p < 0.01). The systematic review included 28 studies with 103 patients. Receipt of adjuvant chemotherapy was associated with significantly lower mean MRC score (3.00 ± 1.35 vs. 3.90 ± 1.36; p = 0.019). Seventy-four percent of the patients underwent free FMT, with the most common donor muscle being the latissimus dorsi (55%). The flap loss rate was 0.8%. Neoadjuvant chemotherapy (p = 0.03), radiotherapy (p = 0.05), pedicled FMTs (p = 0.01), and a recipient femoral nerve (p = 0.02) were associated with significantly higher complication rates. The institutional retrospective review identified 13 patients who underwent FMT after oncological resection with a median follow-up time of 21 months (range: 6-74 months). The most common tumor necessitating FMT was undifferentiated pleomorphic sarcoma (77%), and the most common donor muscle was the latissimus dorsi (62%). A high body mass index was associated with prolonged neuromuscular recovery (R = 0.87, p = 0.002).

CONCLUSION

 FMT after oncological resection may contribute to improved extremity function. Careful consideration of risk factors and preoperative planning is imperative for successful FMT outcomes.

A systematic review of nerve grafting, end-to-end repair, and nerve transfer for obturator nerve injuries

OBJECTIVE

Obturator nerve injury can occur as a complication of gynecologic surgeries, occurring most frequently in patients with endometriosis and genitourinary malignancies. The resulting injury causes paresthesia and major weakness in adduction and atrophy of the adductor group of lower extremity muscles. The objective of this study was to conduct a systematic review and meta-analysis of the effectiveness of end-to-end repair, nerve grafting, and nerve transfer in improving motor function in patients with obturator nerve injury.

METHODS

PubMed, Cochrane, Medline, and Embase libraries were searched from May 1994 to August 2020 according to the PRISMA guidelines for articles that present functional outcomes after obturator nerve injury in patients treated with nerve grafting, end-to-end repair, or nerve transfer.

RESULTS

A total of 25 patients from 22 studies were included in the study, 15 of whom were treated with end-to-end repair (60%), nine with nerve grafting (36%), and one with nerve transfer (4%). Of the 15 patients with transection data, two had incomplete (13%) and 13 had complete (87%) nerve transections. The patients underwent pelvic lymphadenectomy (n=24) and radical cystectomy (n=1) operations. The mean Medical Research Council (MRC) score was 2.95±1.7 immediately after treatment and 4.77±0.6 at the final follow-up. All patients achieved good outcomes (MRC ≥3) at the final follow-up. The mean MRC score for end-to-end repair (n=15), nerve grafting (n=9), and nerve transfer (n=1) was 4.8±0.6, 4.7±0.8, and 5, respectively. Patients with end-to-end repair had higher immediate post-operative strength than those treated with nerve grafting (p=0.03) and tended to achieve full functional recovery after shorter periods of time (rho=-0.65, p=0.049). Other parameters did not correlate with MRC.

CONCLUSION

End-to-end repair, nerve grafting, and nerve transfer are equally effective in restoring function in patients with obturator nerve injury. However, patients treated with end-to-end repair had higher immediate post-operative strength than those treated with nerve grafting.