Transfer of the palmaris brevis motor branch to the thenar motor branch: A cadaveric preliminary study

OBJECTIVE

High median nerve injuries can lead to poor distal recovery, especially poor functioning of median innervated thenar muscles involved in thumb opposition and palmar abduction. The palmaris brevis (PB) is a small subcutaneous muscle innervated by ulnar nerve. Innervation of the PB is in most of cases provided by the ulnar digital nerve to the little finger. The purpose of this study is to assess the feasibility of transferring the PB motor branch (PBMB) to the median nerve thenar motor branch (TMB), in order to allow for early restoration of thumb palmar abduction and opposition, through a preliminary cadaveric study.

METHODS

Twenty-five cadaver upper limbs were dissected under magnification. The length of the PBMB and TMB, and their origin were recorded. Nerve transfer from PBMB to TMB was conducted, and evaluated on 2 parameters: surgical feasibility, and distance from the coaptation site to the recipient nerve muscle entry point. The PBMB and TMB were harvested, fixated in formalin, then embedded in paraffin. They were sectioned transversely, and stained with a combination of hematoxylin-eosin and Luxol fast blue. Myelinated axons were counted in each specimen and the donor-to-recipient axon ratio was recorded.

RESULTS

The PBMB was constant and originated from the ulnar digital nerve of the little finger in all cases. The transfer from PBMB to TMB was feasible in all cases. Mean myelinated axon counts of PBMB and TMB were 253±142 and 356±198, respectively (p=0.06). The donor-to-recipient axon ratio was 1:1.41. The mean distance from coaptation of the PBMB to the recipient thenar muscles was 23.1±3.0mm.

CONCLUSIONS

Based on our results, PBMB to TMB transfer is feasible. The PBMB has the advantage over other distal nerve transfer donors to be constant and superficial, allowing for an easier harvest. Moreover, this procedure does not sacrifice any intrinsic function of the hand, and the proximity of the PBMB with the carpal tunnel allows for a single incision procedure. Therefore, early restoration of the median innervated thenar muscles may be feasible by the PBMB to TMB transfer in cases of high median nerve lesions.

LEVEL OF EVIDENCE

IV.

Neurolymphomatosis of the median nerve, optic nerve, L4 spinal nerve root and cauda equina in patients with B-cell malignancies: a case series

BACKGROUND

Neurolymphomatosis is rare. Neoplastic lymphocytes are seen to invade nerves (cranial or peripheral), nerve roots or other related structures in patients with hematological malignancy. It is a separate entity from central nervous system lymphoma. Neurolymphomatosis has most commonly been described in association with B-cell non-Hodgkin lymphoma. Neurolymphomatosis in the context of Burkitt lymphoma and the post-renal transplant setting has not been described before.

CASE REPORTS

We report for the first time in the Arabian Gulf countries and nearby Arab states four cases of neurolymphomatosis (one Asian, and the other 3 are from Arabic nationals) occurring between 2012 and 2017 involving the median nerve, optic nerve, nerve root and cauda equina in patients with Burkitt lymphoma, Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia and diffuse large B-cell lymphoma.

CONCLUSIONS

Neurolymphomatosis is rare and can be difficult to diagnose by biopsy but reliably confirmed by a combined imaging approach. Prior treatment with high-dose dexamethasone might suppress 18F-fluorodeoxyglucose (FDG) activity and decrease the sensitivity of positron emission tomography/computed tomography (PET/CT). The prognosis is generally poor but using high-dose methotrexate as well as high-dose chemotherapy and autologous stem cell transplantation may be an effective way to treat neurolymphomatosis.

Functional evaluation of early tendon transfer for thumb opposition in median nerve palsy

BACKGROUND

There is paucity of literature on early tendon transfer in surgical rehabilitation of hands with median nerve injuries. Since the single most important functional deficit in median nerve palsy is the loss of thumb opposition, we evaluated the results of early tendon transfer in restoration of thumb opposition.

METHODS

This prospective study involved 10 cases of isolated median nerve paralysis (axonotmesis or neurotmesis) that underwent early tendon transfer for restoration of thumb opposition. A pre- and post-operative evaluation in terms of power and precision grip strength and range of opposition of thumb was done. Median nerve exploration was performed in 4 cases and was supplemented by a tendon transfer for thumb opposition. The extensor indicis proprius (EIP) opponensplasty was performed in nine out of ten cases. In one case where the patient had scarring over the EIP tendon, palmaris longus (PL) opponensplasty was performed.

RESULTS

The median age at injury was 29 years (range; 8 years-57 years). Minimum period of follow-up was 6 months. Six patients who underwent EIP transfer had excellent opposition while 3 had good opposition. The patient, in whom PL opponensplasty was done, had an excellent opposition. The median time for return to work was 2.75 months.There was significant improvement in the power grip and all three types of precision grip at 6 months follow-up. The percentage deficit in the affected hand compared to the normal hand was significantly reduced. There was no case of tendon pull out in our study, nor did any of our patients have an extensor lag following EIP transfer.

CONCLUSION

Early tendon transfer has a unique role in the management of median nerve palsy hand and we suggest this procedure should be considered in both high and low lesions.