Distraction, Compression, Extension, and Reduction Combined With Joint Remodeling and Extra-articular Distraction: Description of 2 New Modifications for Its Application in Basilar Invagination and Atlantoaxial Dislocation: Prospective Study in 79 Cases

Distraction,_Compression,_Extension,_and_Reduction

Neurosurgery 77:67–80, 2015

Recent strategies for treatment of basilar invagination (BI) and atlantoaxial dislocation (AAD) are based on simultaneous posterior reduction and fixation.

OBJECTIVE: To describe new modifications of the procedure distraction, compression, extension, and reduction (DCER), ie, joint remodeling (JRM) and extra-articular distraction (EAD) in patients with “vertical” joints, and to quantify the improvement in joint indices, ie, sagittal inclination (SI), craniocervical tilt (CCT), and coronal inclination.

METHODS: Prospective study (May 2010 to September 2014). Joint indices measured included (normal values): SI (87.15 ± 5.65º), CCT (60.2 ± 9.2), and coronal inclination (110.3 ± 4.23). Surgical procedures included DCER alone (performed in SI ,100, group I) or JRM with DCER (in SI: 100-160, group II), or EAD with DCER in severe BI with almost vertical joints (SI >160º, group III).

RESULTS: Seventy-nine patients were selected (mean, 22.5 years of age). All conventional indices improved significantly (P < .001). CCT improved in all groups (P < .01); group I (n = 32): 54 ± 8.7 (preoperative 80.71 ± 12.72); group II (n = 40): 58 ± 7.0 (preoperative 86.5 6 14); group III (n = 7): 62 ± 10.0 (preoperative 104 6 11.2). SI improved in both group I and II, P < .01 (cannot be measured in group III). At long-term follow-up (n = 64, 29 ± 8 months, range 12-39 months), the Nurick grade improved to 1.5 ±0.52 (preoperative: 3.4 6 0.65; P < .001).

CONCLUSION: DCER seems to be an effective technique in reducing both BI and AAD. JRM and EAD with DCER are useful in moderate to severe BI and AAD (with SI .100). Joint indices provide useful information for surgical strategy and planning.

Analysis of the uncinate processes of the cervical spine

J Neurosurg Spine 16:402–407, 2012. http://thejns.org/doi/abs/10.3171/2011.12.SPINE11541

Although the uncovertebral region is neurosurgically relevant, relatively little is reported in the literature, specifically the neurosurgical literature, regarding its anatomy. Therefore, the present study aimed at further elucidation of this region’s morphological features.

Methods. Morphometry was performed on the uncinate processes of 40 adult human skeletons. Additionally, range of motion testing was performed, with special attention given to the uncinate processes. Finally, these excrescences were classified based on their encroachment on the adjacent intervertebral foramen.

Results. The height of these processes was on average 4.8 mm, and there was an inverse relationship between height of the uncinate process and the size of the intervertebral foramen. Degeneration of the vertebral body (VB) did not correlate with whether the uncinate process effaced the intervertebral foramen. The taller uncinate processes tended to be located below C-3 vertebral levels, and their average anteroposterior length was 8 mm. The average thickness was found to be 4.9 mm for the base and 1.8 mm for the apex. There were no significant differences found between vertebral level and thickness of the uncinate process. Arthritic changes of the cervical VBs did not necessarily deform the uncinate processes. With axial rotation, the intervertebral discs were noted to be driven into the ipsilateral uncinate process. With lateral flexion, the ipsilateral uncinate processes aided the ipsilateral facet joints in maintaining the integrity of the ipsilateral intervertebral foramen.

Conclusions. A good appreciation for the anatomy of the uncinate processes is important to the neurosurgeon who operates on the spine. It is hoped that the data presented herein will decrease complications during surgical approaches to the cervical spine.