Working Diagnosis:
Congenital C2-C3 vertebral fusion

Treatment:
Initial treatment focused on presumed post-concussion symptoms with vestibular rehabilitation, cervical physical therapy, and speech-language pathology evaluation. No medications were prescribed.

Following identification of congenital C2-C3 vertebral fusion, management shifted toward education, risk counseling, and activity modification. The patient and his family were counseled regarding the potential risks associated with continued participation in collision sports and the biomechanical stress placed on adjacent cervical motion segments.

Outcome:
Following independent evaluations by Physical Medicine and Rehabilitation and Orthopedic Spine specialists, the patient was medically disqualified from collision sports.

He subsequently discontinued participation in wrestling and football and transitioned to distance running for ongoing athletic participation.

Author's Comments:
Congenital cervical vertebral fusion represents an uncommon structural abnormality that can complicate the evaluation of athletes presenting with persistent or recurrent symptoms following sport-related concussion. Although many individuals remain asymptomatic, altered cervical biomechanics may become clinically relevant when athletes are exposed to repetitive loading through collision and contact sports(4-6).

This case highlights the importance of reconsidering the diagnosis when an athlete's clinical course deviates from the expected recovery trajectory. The recurrence of symptoms in the absence of a new mechanism of injury, combined with progressive focal cervical tenderness and restricted cervical motion, prompted further evaluation and ultimately led to identification of an underlying congenital cervical anomaly.

A second important teaching point is the value of serial concussion assessment rather than reliance on a single testing session. In this case, symptom recurrence was accompanied by worsening SAC and BESS performance, while VOMS findings normalized. Although no single concussion assessment tool is intended to identify structural cervical pathology, changes in cognitive, balance, and vestibular measures over time may signal the need to reconsider the working diagnosis and investigate alternative etiologies. Evaluating trends across serial assessments may provide greater clinical insight than interpreting each assessment in isolation(1-3).

Routine cervical imaging is not indicated in the evaluation of sport-related concussion(7). However, recurrent symptoms without new trauma, progressive focal cervical tenderness, restricted cervical range of motion, or failure to progress through standard rehabilitation should prompt consideration of cervical spine imaging. In this patient, plain radiographs followed by magnetic resonance imaging identified a congenital abnormality that substantially altered management and sports participation recommendations.

This case reinforces the importance of maintaining a broad differential diagnosis in athletes with persistent or recurrent post-concussive symptoms and demonstrates how targeted cervical spine imaging can uncover clinically significant structural pathology when the clinical presentation becomes atypical.

Editor's Comments:
This case highlights several important principles in sports spine biomechanics, athletic clearance, and diagnostic evaluation.

1. Biomechanical Consequences of Upper Cervical Fusion: Congenital C2-C3 vertebral fusion creates a rigid functional unit that alters normal cervical motion and transfers stress to adjacent motion segments. In collision sports involving repetitive axial loading, such as wrestling and football, these altered biomechanics may increase susceptibility to adjacent segment degeneration, instability, and neurological injury(4-6).

2. Collision Sport Participation and Medical Disqualification: Congenital fusion involving the upper cervical spine has been identified as an important consideration when determining eligibility for collision sport participation. Published recommendations have historically advised caution in athletes with upper cervical or multilevel congenital fusion because of the potential for serious neurologic injury associated with adjacent segment stress and high-energy cervical trauma(5-6).

3. Diagnostic Imaging Pearl: Routine cervical spine imaging is not indicated as part of the standard evaluation of concussion. However, recurrent symptoms without a new mechanism of injury, progressive focal cervical tenderness, restricted cervical range of motion, or failure to progress through standard rehabilitation should prompt consideration of cervical spine imaging. As demonstrated in this case, plain radiographs can serve as an accessible initial diagnostic tool and may identify clinically significant structural abnormalities requiring further evaluation with advanced imaging(7).

References:
1. McCrea M, Kelly JP, Randolph C, et al. Standardized assessment of concussion (SAC): on-site mental status evaluation of the athlete. J Head Trauma Rehabil. 1998;13(2):27-35. doi:10.1097/00001199-199804000-00005

2. Bell DR, Guskiewicz KM, Clark MA, Padua DA. Systematic review of the Balance Error Scoring System. Sports Health. 2011;3(3):287-295. doi:10.1177/1941738111403122

3. Mucha A, Collins MW, Elbin RJ, et al. A brief vestibular/ocular motor screening (VOMS) assessment to evaluate concussions: preliminary findings. Am J Sports Med. 2014;42(10):2479-2486. doi:10.1177/0363546514543775

4. Samartzis D, Lubicky JP, Herman J, Shen FH. Klippel-Feil syndrome and associated abnormalities: the necessity for a multidisciplinary approach in patient management. Spine J. 2007;7(1):135-137. doi:10.1016/j.spinee.2006.05.019

5. Torg JS, Ramsey-Emrhein JA. Management guidelines for participation in collision activities with congenital, developmental, or post-injury lesions involving the cervical spine. Clin J Sport Med. 1997;7(4):273-291. doi:10.1097/00042752-199710000-00005

6.Vaccaro AR, Klein GR, Ciccotti M, et al. Return to play criteria for the athlete with cervical spine injuries resulting in stinger and transient quadriplegia/paresis. Spine J. 2002;2(5):351-356. doi:10.1016/S1529-9430(02)00202-4

7. Davis GA, Schneider KJ, Anderson V, et al. Pediatric sport-related concussion: recommendations from the Amsterdam consensus statement 2023. Pediatrics. 2024;153(1):e2023063489. doi:10.1542/peds.2023-063489

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