Dados do Trabalho

Título

FUNCTIONAL AND MORPHOLOGICAL EVALUATION OF THE TRAPEZIUS MUSCLE AFTER SPINAL ACCESSORY NERVE TRANSFER TO BRACHIAL PLEXUS NERVES

Introdução e Objetivo

Introduction: The main innervation of the trapezius muscle is provided by the spinal accessory nerve. Several studies describe the contributions of cervical plexus roots to the trapezius muscle innervation, either directly or through connections with the spinal accessory nerve. There is no adequate understanding of how the trapezius muscle is affected after using the spinal accessory nerve in nerve transfer procedures with the usual technique, preserving at least 1 branch for the upper trapezius. Objective: To evaluate function, morphology and neurophysiology of the trapezius muscle (three portions) in patients who underwent nerve transfer procedures using the spinal accessory nerve and verify if there is a correlation between the results obtained in the three evaluation methods.

Material e Método

We evaluated 20 patients with sequelae of traumatic brachial plexus injury who underwent surgical procedures for brachial plexus repair or free muscle transfer, which included the spinal accessory nerve transfer technique and were followed fora minimum of 1 year. The three portions trapezius muscle were evaluated by physical examination, magnetic resonance imaging (analysis of fatty degeneration) and electromyography.

Resultados

In all evaluation methods, the middle and lower portions of the trapezius muscle showed more significant morphological and/or functional impairment than the upper portion, in most cases. There was a statistically significant difference in all the complementary exams results, between the affected side (with sacrifice of the nerve) versus the normal side, in the middle and lower portions of the trapezius muscle.

Discussão

No comparable studies were identified that specifically assess alterations in the three portions of the trapezius muscle (TM) among patients who underwent nerve transfer involving the SAN, employing the methodologies utilized in this study.

Conclusão

Physical examination alone is not sufficient to determine the residual functionality of the trapezius muscle. Magnetic resonance imaging and electromyography are useful tools to assess both morphological involvement of the trapezius muscle and nerve conduction impairment of the trapezius muscle, respectively. The results suggest that the middle and lower portions of the trapezius muscle are affected by previous SAN transfer and should be considered with caution for further muscle transfer procedures.