Influence of surgical approach on the efficacy of the intervertebral disk fenestration: a cadaveric study.
OBJECTIVE
To investigate the influence of different approach angles on the amount of nucleus pulposus removed during intervertebral disc fenestration in dogs.


METHODS
Twenty cadavers of beagle dogs were randomly divided into four groups: a control group and three treatment groups in which intervertebral fenestration was performed using either a dorsal, dorsolateral or lateral approach between the 12th thoracic and second lumbar spaces. The volume of nucleus pulposus, the weight of the residual nucleus pulposus and the angle of the working sector were measured. The ratio of the residual nucleus pulposus weight to the nucleus pulposus volume was used to evaluate the efficacy of the performed fenestration. Data were analysed with Kruskal-Wallis analysis of variance between groups on ranks with correction for ties and Bonferroni correction for multiple comparisons. Correlation between ratio and working angle was calculated using a Spearman's rank test (P<0.05).


RESULTS
The calculated ratio of nuclear weight to volume was significantly less in the lateral approach group than that in the other groups. The working sector was widest in the dorsolateral approach group, but this did not correlate with efficient fenestration.


CONCLUSIONS
Using the lateral approach for intervertebral disc fenestration may increase the efficiency of the fenestration procedure.
Morelius
M
M
Section of Small Animal Orthopaedics and Surgery, Department of Clinical Veterinary Medicine, Vetsuisse-Faculty University of Berne, Länggass-Strasse 128, CH-3012 Bern, Switzerland.
Bergadano
A
A
Spreng
D
D
Schawalder
P
P
Doherr
M
M
Forterre
F
F
D000818:Animals; D002102:Cadaver; D004285:Dogs; D007403:Intervertebral Disc / Q000601:surgery*; D007405:Intervertebral Disc Displacement / Q000601:surgery / Q000662:veterinary*; D007796:Laminectomy / Q000379:methods / Q000662:veterinary*; D008159:Lumbar Vertebrae; D013904:Thoracic Vertebrae