Neurophysiological signals for estimation of the result of latissimus dorsii muscle transfer to biceps brachii in patients with arthrogryposis

Abstract

Background. One of the leading causes of restriction in daily-living activities in patients with arthrogryposis is severe hypoplasia (or aplasia) of the biceps brachii. Latissimus dorsii muscle transfer to the biceps brachii is one of the most used methods for the reconstruction of active elbow flexion in patients with arthrogryposis.
 Aim. The aim of the study is to identify neurophysiological correlates for evaluating the result of the transposition of the latissimus dorsii muscle to the biceps in patients with multiple congenital arthrogryposis.
 Materials and methods. From 2011 to 2018, we performed monopolar latissimus dorsii muscle transfer to the biceps for the restoration of active elbow flexion in 30 patients with arthrogryposis (44 upper extremities). The follow-up results were studied in 14 cases. For this purpose, we used clinical examination, surface electromyography (sEMG), and statistical analysis. The patients were examined before and from 1 month to 96 months (7 months; 224.5 months) after the surgery. The age of patients was from 1 to 10 years at the time of surgery (4.89 2.42 years).
 Results. Our study showed that the age of the child at the time of surgery does not significantly change the index of activation of the latissimus dorsii muscle. A decrease of coactivation of the latissimus dorsii muscle in the long term after surgery correlates with an increase in the strength of the displaced latissimus dorsii muscle, and an improvement in active flexion in the elbow. If the value of the index of coactivation of the latissimus dorsii muscle is less 42%, the muscle strength after surgery reaches 4 points. It was found that the index of coactivation of the latissimus dorsii muscle does not depend on the level of segmental damage to the spinal cord. However, the strength of the muscle depends on the level of spinal cord damage.
 Conclusion. The determination of the index coactivation of the latissimus dorsii muscle after surgery can be used to evaluate the results of the latissimus dorsii muscle transfer to the biceps in patients with arthrogryposis. The index of activation of the latissimus dorsii muscle must be less than 42% for effective elbow active flexion.