Value of neurophysiologic monitoring in confirming indirect decompression of severe pediatric non-traumatic C1–C2 subluxation. A case report

Spinal cord compression from severe C1–C2 subluxation is a complex and challenging neurosurgical problem. A combination of surgical approaches may be required to decompress the spinal cord, including anterior transoral odontoidectomy, posterior cervical laminectomy, or indirect decompression by subluxation reduction. After decompression, an instrumented posterior fusion is then required to stabilize the spine. We report a case of a 13-year-old-girl who presented with spastic quadriparesis secondary to severe atlantoaxial subluxation, where intraoperative neurophysiologic monitoring (IOM) guided surgical decision making. The patient had congenital osseous abnormalities, including incomplete segmentation of C2 on C3, predisposing her to atlantoaxial dislocation. She underwent open surgical reduction of the C1–C2 subluxation with multi-modal intraoperative neurophysiologic guidance. Translaminar C2 screws and C1 lateral mass screws were placed bilaterally. Using a previously described distraction technique, we performed ventral translation of C2 relative to C1, thereby reducing the subluxation. Intraoperative radiographic images and neurophysiologic monitoring revealed significant improvements, confirming that adequate indirect decompression had been achieved. After subluxation reduction with intraoperative monitoring (IOM) improvements, we decided to proceed with a C1–C2 posterior fusion and avoid a cervical laminectomy and more extensive occipital cervical fusion procedure. After one year, the girl made a complete neurologic recovery and remains symptom-free 3 years post-surgery. Fusion to the occiput would have potentially caused greater morbidity in this patient. The neurophysiologic monitoring confirmed indirect decompression and served as a critical tool for the prediction of favorable neurologic outcome. Keywords: Atlanto-axial, Cervical traction, Intraoperative monitorin