P3.R358: Thoracic Outlet Syndrome in a Teenage Softball Pitcher: A Rare Presentation of Biceps Pain

Introduction: Thoracic outlet syndrome (TOS) is a condition caused by compression of the nerves and vessels of the brachial plexus in a region called the thoracic outlet. The thoracic outlet is the space between the collarbone and first rib. Symptoms include pain in the neck and shoulder, numbness in the upper extremities, and a weak grip. TOS is most commonly associated with overhead athletes, especially baseball pitchers. Swimmers and volleyball players also make up a significant portion of patients with TOS. We present a case of TOS in a high school softball pitcher to improve understanding of this condition in a less common patient population.

Case Description: A 16-year-old female softball pitcher presented with a chief complaint of right biceps pain. She was unable to extend her right elbow, experienced hand and finger swelling, and felt numbness and tingling in her hand. Physical examination revealed ligamentous laxity about the shoulder, elbow, and knees, as well as positive Adsons and Roos tests. X-rays of the neck, shoulder, and elbow taken in July 2021 showed bifid spinous processes (C4-6) and elongation of spinous processes (C6-7), no disc abnormalities and no cervical rib. The patient was diagnosed with neurovascular impingement from overuse, consistent with TOS. Patient underwent arterial and venous doppler ultrasound which revealed vascular TOS. The patient then underwent first rib resection, resulting in resolution of her symptoms.

Discussion: While TOS is most commonly associated with overhead athletes such as baseball pitchers, volleyball players, and swimmers, it should also be considered for softball pitchers presenting with similar symptoms. The unique biomechanics used in pitching a softball, such as the rapid windmill motion, may still lead to increased stress on the thoracic outlet. Moreover, ligamentous laxity and hypermobility syndrome may further contribute to the development of TOS in these patients.

Conclusion: This case highlights the importance of considering TOS in the differential diagnosis of biceps pain and upper extremity symptoms not only in overhead athletes but also athletes that primarily use underhand movements. In particular, pediatric patients participating in sports may be more prone to overuse injuries because of their skeletal immaturity and a potentially limited understanding of their physical limitations. The prevention and treatment of TOS can be improved by better taking into account the whole patient, including their anatomy, biomechanics, pathophysiology, and training routines. Further research is needed to better understand the optimal management of TOS in softball pitchers and pediatric patients in general.