Mixed Reality–Assisted Surgical Planning and Patient Education in a Complex Craniovertebral Junction Anomaly: A Case Report

Basilar invagination with assimilated atlas in adults may be accompanied by degenerative arthropathy, which can worsen instability and lead to neurological deterioration. A 36-year-old woman with a short neck presented wheelchair bound with complaints of chronic neck pain, bilateral hand clumsiness, and urinary urgency. Examination showed spastic quadriparesis, sensory impairment below the neck, and positive hand myelopathic signs (modified Japanese Orthopaedic Association score 9/18). Imaging demonstrated basilar invagination and assimilated atlas with asymmetric C1 to C2 facet joints, with severe cord compression and myelomalacia. Computed tomography and magnetic resonance imaging datasets were combined in a mixed reality (MR) viewer to generate 3-dimensional visualization. Using MR, the patient and family were counseled about the need for surgery. MR also facilitated preoperative surgical planning by improving anatomical understanding, particularly regarding the anatomy of asymmetric facets and screw trajectories. The patient underwent a posterior C1 to C2 joint reconstruction, reduction with facet spacers, and fusion using the Goel technique. At 1-year follow-up, the patient was able to ambulate on her own with improved neurology (modified Japanese Orthopaedic Association score 18/18). Reports describing MR applications in the evaluation and surgical planning of complex craniovertebral junction anomalies remain limited. In this case report, we describe the successful management of a complex craniovertebral junction anomaly and how MR devices supported the preoperative planning and facilitated counseling of an anxious patient.