Restoring the function in neuralgic shoulder amyotrophy by modified Somsak nerve transfer

Background and Objectives: Neuralgic amyotrophy (NA), also known as Parsonage-Turner syndrome, is a rare and acute neuropathy of the shoulder and/or arm. It is characterized by sudden pain attacks, followed by patchy muscle paresis in the upper extremity. The frequency of remaining neurological deficits varies in the literature between 10% and 66%. In addition to other therapeutic strategies, nerve branch transposition might be a possible treatment option to improve muscle strength and reduce pain symptoms. Transposition of the first motor triceps branch to the axillary nerve was first described in 2003 to regain the deltoid muscle function in patients with C5 (C6) root injury.To our knowledge, this is the first description of nerve transfer for treating permanent paresis in NA. Methods: We present the case and the surgical treatment of a 16-year-old male with loss of axillary nerve function due to NA on both upper extremities. Neurological examination before surgery, 6 and 12 months after surgery included analysis of the upper extremity range of motion and muscle strength evaluated using the Medical Research Council Scale. Results: Shoulder function and muscle strength improved significantly 12 months after surgery. The range of motion of arm abduction improved from 90 degrees preoperatively, to as high as 120 degrees at 6 months, and to 130 degrees at 12 months. Muscle strength was strength grade 2/5 preoperatively, 3/5 at 6 months, and 4+/5 at 12 months. Subjectively, the patient also has a significantly improved quality of life.Conclusion: Nerve transfer is a promising treatment method for patients suffering from NA.