311 - Transoral Atlantoaxial Reduction Plate Internal Fixation for the Treat...

#311 Transoral Atlantoaxial Reduction Plate Internal Fixation for the Treatment of Basilar Invagination Combined with C1-2 Dislocation

Oral Posters: Cervical

Presented by: X. Hong

Author(s):

X. Hong (1)
Q.-S. Yin (1)
F.-Z. Ai (1)
M. Xiangyang (1)
J.-H. Wang (1)
Z. Wu (1)
K. Zhang (1)
J. Liu (1)

(1) Guangzhou Army General Hospital, Orthopeadics, Guangzhou, China

Abstract

Study Design: Retrospective report of twenty-one surgical cases and review of the literature.

Objective: To introduce the surgical technique and the curative effect of transoral atlantoaxial reduction plate (TARP) internal fixation for the treatment of basilar invagination with irreducible atlantoaxial dislocation.

Summary of Background data: Irreducible atlantoaxial dislocation with ventral spinal cord compression in case of basilar invagination presents a difficult surgical challenge. Posterior decompression followed by atlantoaxial or occipitocervical fusion can rarely obtain satisfactory decompression and thorough atlantoaxial reduction. Although direct transoral decompression and one-stage posterior instrumentation can obtain satisfactory cord decompression, it needs combinative anterior-posterior approaches, which will increase the surgical injuries. Furthermore, if the decompression includes dens and/or clivus, the surgical technique is relatively complicated and the complications will be notablely increased.

Methods: 21 consecutive patients with basilar invagination underwent the TARP operation. The pre- and postoperative medulla-cervical angle were measured and compared. The JOA score of spinal cord function was calculated pre- and postoperatively.

Results: 20 cases (20/21) were followed-up to average 12.5 months. The symptoms of all the 20 cases were relieved in different degree. The postoperative imaging showed the odontoid processes obtained ideal reduction and the internal fixators were all in good position. The preoperative medulla-cervical angle was averagely 128.4°(n=21). The postoperative medulla-cervical angle was averagely 156.5°(n=20) and increased by 27.9° compared with that of preoperation. The postoperative data were in normal range (143.64°-165.42°). The JOA score improved from 12.43(n=21) pre-operatively to 15.9 (n=20) post-operatively and the average improvement rate was 76%. Screw-loosening was observed in one patient due to severe osteoporosis. After a revising operation with a TARP in another size, the neurological symptoms didn't improve obviously. Then the treatment was terminated.

Conclusions: By virtue of adjunctive reduction system, the TARP operation could reduce the odontoid process superiorly migrating into the foramen magnum, directly decompress the ventral compression of spinal cord, and fix the reduced atlantoaxial joints by a single transoral approach without the need of a followed posterior operation. The preliminary clinical result was satisfactory.

Keywords: Atlantoaxial joints; Basilar invagination; Arthrodesis; Internal fixator