Stability of the craniovertebral junction after unilateral occipital condyle resection: a biomechanical study.


Journal Article

OBJECT: The authors sought to determine the biomechanics of the occipitoatlantal (occiput [Oc]-C1) and atlantoaxial (C1-2) motion segments after unilateral gradient condylectomy. METHODS: Six human cadaveric specimens (skull with attached upper cervical spine) underwent nondestructive biomechanical testing (physiological loads) during flexion-extension, lateral bending, and axial rotation. Axial translation from tension to compression was also studied across Oc-C2. Each specimen served as its own control and underwent baseline testing in the intact state. The specimens were then tested after progressive unilateral condylectomy (25% resection until completion), which was performed using frameless stereotactic guidance. At Oc-C1 for all motions that were tested, mobility increased significantly compared to baseline after a 50% condylectomy. Flexion-extension, lateral bending, and axial rotation increased 15.3%, 40.8%, and 28.1%, respectively. At C1-2, hypermobility during flexion-extension occurred after a 25% condylectomy, during axial rotation after 75% condylectomy, and during lateral bending after a 100% condylectomy. CONCLUSIONS: Resection of 50% or more of the occipital condyle produces statistically significant hypermobility at Oc-C1. After a 75% resection, the biomechanics of the Oc-C1 and C1-2 motion segments change considerably. Performing fusion of the craniovertebral junction should therefore be considered if half or more of one occipital condyle is resected.

Full Text

Cited Authors

  • Vishteh, AG; Crawford, NR; Melton, MS; Spetzler, RF; Sonntag, VK; Dickman, CA

Published Date

  • January 1999

Published In

Volume / Issue

  • 90 / 1 Suppl

Start / End Page

  • 91 - 98

PubMed ID

  • 10413132

Pubmed Central ID

  • 10413132

International Standard Serial Number (ISSN)

  • 0022-3085

Digital Object Identifier (DOI)

  • 10.3171/spi.1999.90.1.0091


  • eng

Conference Location

  • United States