Three-dimensional kinematic analysis of the cervical spine after anterior cervical decompression and fusion at an adjacent level: a preliminary report.

Abstract

PURPOSE:

Development of adjacent segment degeneration following anterior cervical decompression and fusion (ACDF) is still controversial, as adjacent-level kinematics is poorly understood. This study reports preliminary data from a high-accuracy 3D analysis technique developed for in vivo cervical kinematics.

METHODS:

From nine cervical spondylosis patients, four underwent single-level ACDF, and five underwent two-level ACDF using cylindrical titanium cage implant(s). Pre- and post-surgical CT scans were taken in flexion, neutral and extended positions, allowing us to compute segmental ranges of motion for rotation and translation, and 3D disc-height distributions. Differences in segmental motions and disc-height between fused and adjacent levels were analyzed with a Wilcoxon signed-rank test. Results are presented as mean ± SEM.

RESULTS:

The flexion/extension angular-ROM at the fusion level decreased after surgery (7.46 ± 1.17° vs. 3.14 ± 0.56°, p < 0.003). The flexion/extension angular-ROM at one caudal adjacent level to the fusion level (3.97 ± 1.29°) tended to be greater post-operatively (6.11 ± 1.44°, p = 0.074). Translation in the anterior-posterior direction during flexion/extension at the fusion level decreased after surgery (1.22 ± 0.20 mm vs. 0.32 ± 0.11 mm, p < 0.01). No differences were found in adjacent-level disc heights between both study time-points.

CONCLUSIONS:

This study showed increased segmental motion in flexion/extension angular-ROM at one level adjacent to ACDF. However, increases in the rotational angular-ROM were not statistically significant when cranial/caudal adjacent levels were analyzed separately. This preliminary study highlighted the capabilities of a 3D-kinematic analysis method to detect subtle changes in kinematics and disc height at the adjacent levels to ACDF. Thus, reliable evidence related to ACDF's influence on adjacent-level cervical kinematics can be collected.

• Authors: Sadayoshi Watanabe, Nozomu Inoue, Tomonori Yamaguchi, Yoshitaka Hirano, Alejandro A Espinoza Orías, Shintaro Nishida, Yuichi Hirose, Junichi Mizuno
• Journal: European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society (Eur Spine J) Vol. 21 Issue 5 Pg. 946-55 (May 2012) ISSN: 1432-0932 [Electronic] Germany
• PMID: 22124708 (Publication Type: Evaluation Study, Journal Article)

Topics

• Adult
• Aged
• Algorithms
• Biomechanical Phenomena
• Cervical Vertebrae (diagnostic imaging, physiopathology, surgery)
• Decompression, Surgical (adverse effects, methods)
• Female
• Humans
• Imaging, Three-Dimensional (methods)
• Lumbar Vertebrae (diagnostic imaging, physiopathology, surgery)
• Male
• Middle Aged
• Range of Motion, Articular (physiology)
• Spinal Fusion (adverse effects, methods)
• Spondylosis (physiopathology, surgery)
• Tomography, X-Ray Computed (methods)