Outcome of Surgery for Congenital Craniovertebral Junction Anomalies with Atlantoaxial Dislocation/Basilar Invagination: A Retrospective Study of 94 Patients

Atlantoaxial Instability with Persistent Second Intersegmental Artery

Understanding the anatomy of the vertebral artery is essential while manipulating the craniovertebral joint during surgery. Its anomalous course in congenital atlantoaxial dislocation makes it more vulnerable to injury. Preoperative dedicated computed tomography (CT) angiography helps identify the artery's position and plan for surgical procedure. A 13-year-boy presented with neck pain and spastic quadriparesis for 1 year. Radiological imaging of the craniovertebral junction revealed atlantoaxial instability with basilar invagination. His CT angiography of neck and brain vessels revealed an anomalous course of the vertebral artery due to a persistent second intersegment artery. He underwent posterior atlantoaxial fixation after mobilization of the vertebral artery. His clinical condition significantly improved after surgery. We report a case of management of an atlanto axial dislocation with persistent second intersegment artery and describe the role of vertebral artery mobilization during surgery.

Transoral Odontoidectomy - Our Experience in A Limited-Resource Setup

BACKGROUND

Although posterior procedures are used for most cases of basilar invagination, transoral decompression is an important tool in complex deformities with severe degeneration and neural compression.

METHODS

Consecutive patients who underwent transoral odontoidectomy for basilar invagination and atlantoaxial dislocation at the neurosurgical unit of Lady Reading Hospital Peshawar between June 2016 and January 2022 were retrospectively included. Preoperative and postoperative neurological, clinical, and radiological parameters were recorded and compared.

RESULTS

Of the 33 patients included in this study, 22 were men and 11 were women. The mean age was 23.4 years ±8.4 years (mean ± standard deviation). The most common presenting symptoms were gait abnormalities and neck pain. A total of 28 patients were treated for the first time, while 5 patients had prior posterior fusion. The mean distance of the tip of the dens above the chamberlain line was 8.9 ± 4.2 mm, while the mean anterior atlantodental interval was 6.5 ± 2.1 mm. Seven patients had an anomalous course of vertebral artery on at least one side. A total of 28 patients improved significantly, while 5 patients did not improve at the follow-up. The mean follow-up was 8.5 months ±6.3 (mean ± standard deviation). The mean Nurick and Modified Japanese Orthopedic Association scores improved postoperatively (P < 0.05). Three patients underwent reoperation including one with vertebral artery injury. Three patients underwent tracheostomy.

CONCLUSIONS

With proper patient selection, transoral odontoidectomy can be safely performed in a limited-resource setting.