Editorial Type:
Biomechanics

Effect of width of disk fenestration and a ventral slot on biomechanics of the canine C5-C6 vertebral motion unit

Amy E. Fauber Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.

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Jeremie A. Wade School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907.

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Alex E. Lipka Department of Statistics, College of Science, Purdue University, West Lafayette, IN 47907.

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George P. McCabe Department of Statistics, College of Science, Purdue University, West Lafayette, IN 47907.

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Rhonda L. Aper Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.

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DOI:
https://doi.org/10.2460/ajvr.67.11.1844
Volume/Issue:
Volume 67: Issue 11
Online Publication Date:
01 Nov 2006
Restricted access
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Abstract

Objective—To investigate the effects of disk fenestration and ventral slot formation on vertebral motion unit (VMU) range of motion (ROM) and determine the effects of fenestration and ventral slot width on VMU ROM.

Sample Population—C5-C6 VMUs from 10 skeletally mature canine cadavers.

Procedures—Specimens were assigned to 2 groups (5 specimens/group). Surgery was performed in which width of a fenestration and a ventral slot was 33% (group 1) or 50% (group 2) the width of the vertebral body. Flexion-extension, lateral bending, and axial torsion ROMs were measured during loading before surgery, after fenestration, and after ventral slot formation. Range of motion was compared within groups to determine effects of surgical procedure on stability and between groups to determine effects of width of fenestration and ventral slot on stability.

Results—For both groups, fenestration resulted in a significant increase in ROM during flexion-extension, compared with results for intact specimens. Ventral slot formation resulted in a significant increase in ROM during flexion-extension and lateral bending, compared with results for intact specimens. Ventral slot formation resulted in a significant increase in ROM only during flexion-extension, compared with results for fenestrated specimens. There were no significant differences in ROM of the intact, fenestrated, and ventral slot specimens between groups.

Conclusions and Clinical Relevance—Analysis of these results suggests that fenestration and ventral slot procedures each affect the biomechanics of the C5-C6 VMU. Width of a fenestration or ventral slot up to 50% of the width of C5-C6 may be clinically acceptable.

Abstract

Objective—To investigate the effects of disk fenestration and ventral slot formation on vertebral motion unit (VMU) range of motion (ROM) and determine the effects of fenestration and ventral slot width on VMU ROM.

Sample Population—C5-C6 VMUs from 10 skeletally mature canine cadavers.

Procedures—Specimens were assigned to 2 groups (5 specimens/group). Surgery was performed in which width of a fenestration and a ventral slot was 33% (group 1) or 50% (group 2) the width of the vertebral body. Flexion-extension, lateral bending, and axial torsion ROMs were measured during loading before surgery, after fenestration, and after ventral slot formation. Range of motion was compared within groups to determine effects of surgical procedure on stability and between groups to determine effects of width of fenestration and ventral slot on stability.

Results—For both groups, fenestration resulted in a significant increase in ROM during flexion-extension, compared with results for intact specimens. Ventral slot formation resulted in a significant increase in ROM during flexion-extension and lateral bending, compared with results for intact specimens. Ventral slot formation resulted in a significant increase in ROM only during flexion-extension, compared with results for fenestrated specimens. There were no significant differences in ROM of the intact, fenestrated, and ventral slot specimens between groups.

Conclusions and Clinical Relevance—Analysis of these results suggests that fenestration and ventral slot procedures each affect the biomechanics of the C5-C6 VMU. Width of a fenestration or ventral slot up to 50% of the width of C5-C6 may be clinically acceptable.

Contributor Notes

Dr. Aper's present address is Eastern Iowa Veterinary Specialty Center, 755 Capital Dr, Cedar Rapids, IA 52404.

Presented in part at the 33rd Annual Conference of the Veterinary Orthopedic Society, Keystone, Colo, February-March 2006.

The authors thank Beth Galle and Dr. Ben Hilberry for assistance with the Purdue Spine Simulator and Dr. Gert Breur for technical assistance.

Address correspondence to Dr. Fauber.
Cover American Journal of Veterinary Research
American Journal of Veterinary Research
Publication Date:
01 Nov 2006
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