Nonoperative Management of a T1 Spinous Process Apophyseal Stress Fracture in an Adolescent Baseball Pitcher: A Case Report.

INTRODUCTION: Overuse-related stress injuries of the thoracic spine are uncommon among adolescent athletes, and apophyseal stress fractures in this region are particularly rare. CASE PRESENTATION: We report a rare case of an apophyseal stress fracture of the first thoracic (T1) spinous process in a 13-year-old elite baseball pitcher. The patient presented with focal upper thoracic pain without any history of trauma. Magnetic resonance imaging (MRI) revealed an open apophyseal physis with cortical irregularity and bone marrow edema at the T1 spinous process, consistent with an apophyseal stress fracture. The patient was managed nonoperatively with upper body rest, followed by a gradual return-to-throwing program. His symptoms resolved, allowing a return to competitive pitching approximately 12 weeks after symptom onset. However, at the 7-month follow-up, CT showed persistent apophyseal fragmentation without osseous union, despite the patient being clinically asymptomatic. CONCLUSION: This case highlights the value of MRI for early detection of thoracic apophyseal stress fractures in adolescent athletes. Importantly, it demonstrates that clinical recovery and return-to-sport can occur even in the absence of radiologic union.