1327 - Botulinum toxin treatment for muscle spasms following traumatic shoulder injury

Case Diagnosis: Muscle spasm in right shoulder.

Case Description: An active 18-year-old female with a history of traumatic right clavicle fracture and subsequent right shoulder arthroscopic scapulothoracic bursectomy and debridement presented with severe muscle spasms in her right shoulder beginning five months post-operatively. The spasms were characterized by elevation and anterior protrusion of her right shoulder that lasted 1 to 2 seconds, occurred approximately every 10 seconds, and were accompanied by increasing pain and crepitus. The patient’s symptoms limited her daily activities, and she had stopped exercising and switched to writing with her non-dominant (left) hand. She demonstrated impaired range of motion and muscle strength in her right shoulder. After failing conservative management with oral muscle relaxers and physical therapy, the patient was treated with intramuscular injection of botulinum toxin type A (BoNT-A) in her right subscapularis (75 units), right pectoralis major (50 units), right trapezius (50 units), and right levator scapulae (25 units).

Discussions: In both the acute and chronic setting, musculoskeletal injury can produce muscle spasms. Intramuscular BoNT-A administration is an effective form of treatment to alleviate muscle spasms by blocking the release of acetylcholine at the neuromuscular junction, preventing muscle contraction. Following treatment, our patient noticed a decrease in the frequency of involuntary shoulder movements and improvement in her symptoms, enabling her to participate in therapy to strengthen her shoulder and neck. She did not report weakness or impaired movement in her shoulder due to treatment. At the time of writing, follow-up is pending and it is not known if repeat injections will be indicated.

Conclusions: The onset of muscle spasms following musculoskeletal trauma and surgery can be delayed and cause significant pain and functional impairment. Treatment with intramuscular BoNT-A at the site of spasms can alleviate painful muscle contractions, allowing patients to better participate in physical therapy and work to restore function.