Transoral resection of a symptomatic odontoid process aneurysmal bone cyst: illustrative case

Abstract

Background: Aneurysmal bone cysts (ABCs) are slow-growing, expansile bone tumors most often observed in the long bones and lumbar and thoracic spine. Anterior column ABCs of the spine are rare, and few cases have described their surgical management, particularly for lesions with extension into the odontoid process and the bilateral C2 pedicles. In the present case, the authors describe a two-stage strategy for resection of a symptomatic 2.3 × 3.3 × 2.7-cm C2 ABC with cord compression in a 13-year-old patient.

Observations: Initial tumor debulking was completed via a transoral approach, and resection of the involved region spanning the odontoid process to the C2-3 disc space was continued until visualization of the posterior longitudinal ligament. After appropriate decompression was confirmed, the patient was repositioned prone for removal of the residual tumor among the bilateral C2 pedicles. Posterior instrumentation was placed from the occiput to C4, with an autologous rib graft to encourage fusion. The postoperative recovery was uneventful, and 2-month imaging demonstrated postsurgical changes, resolution of compression, and a stable position of the instrumentation and graft material.

Lessons: The transoral approach facilitates sufficient exposure for the resection of large odontoid ABCs, and posterior stabilization can reduce the risk of postsurgical cervical subluxation. https://thejns.org/doi/10.3171/CASE2485.

Keywords: aneurysmal bone cyst; odontoid; spine; transoral; tumor.

FIG. 1.

Preoperative T2-weighted (A) and T1-weighted postcontrast (B) magnetic resonance images showing a large, multicystic enhancing mass of the odontoid, extending posteriorly and circumferentially with ventral cord compression. Concomitant CT scan (C) demonstrating extensive bony lysis of the odontoid with a minimal rim of surrounding cortical bone.

FIG. 2.

Preoperative positioning for the transoral approach to the anterior CVJ (A) with elevation of the uvula and wide visualization of the posterior palate (B). Extensive anterior resection and curettage with visualization of the posterior longitudinal ligament (C) and same-day posterior fusion with placement of occiput–C4 hardware and C1–4 rib autograft (D).

FIG. 3.

Early postoperative anteroposterior (left) and lateral (right) radiographic assessment confirming stabilization with correction of cervical lordosis and proper placement of the hardware. L = left side.

FIG. 4.

Two-month postoperative T2-weighted (A) and T1-weighted postcontrast (B) magnetic resonance images demonstrate minimal residual T2 signal suspected to be postoperative artifact, whereas CT scans (C) demonstrate significant bony removal of the odontoid with stable positioning of posterior hardware and bone graft (D).