Transfert des branches nerveuses de l’Extensor Digiti Minimi et de l’Extensor Carpi Ulnaris sur les nerfs moteurs intrinsèques. Une étude histologique sur cadavre

Abstract Background In cases of high ulnar and median nerve palsy, result of nerve repair in terms 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, 30,960 and 35,426, respectively. In this study, the number of axons in the EDM and ECU branches was 37 % (13,281/35,426) of that in the DBUN. Also, the number of axons in the EDM and ECU branches was 42 % (13,281/30,960) 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).