Ultrasound-Guided Ulnar Nerve Hydrodissection for Post-brachioplasty Cubital Tunnel Syndrome in a Patient With Congenital Myasthenic Syndrome: A Case Report

Cubital tunnel syndrome is a common entrapment neuropathy of the upper extremity, typically resulting from compression of the ulnar nerve at the elbow.Postsurgical scarring is a less frequently discussed etiology, particularly following cosmetic procedures such as brachioplasty.We present the case of a 31-year-old female with a history of massive weight loss and bilateral brachioplasty who developed progressive ulnar neuropathic symptoms despite normal electrodiagnostic testing.The patient also carried a diagnosis of congenital myasthenic syndrome (CMS), complicating clinical interpretation.Ultrasound demonstrated ulnar nerve enlargement and tethering beneath brachioplasty scar tissue.The patient was successfully treated with ultrasound-guided ulnar nerve hydrodissection using dextrose, local anesthetic, and corticosteroid.This case highlights the limitations of electromyography (EMG) in dynamic or scar-related neuropathies, the potential contribution of brachioplasty scarring to cubital tunnel syndrome, and the role of ultrasound-guided hydrodissection as a minimally invasive alternative to surgery.