[Pediculoscopic assisted transpedicular spongioplasty for interbody fusion of the lumbar spine. An animal experiment study of the sheep model].
OBJECTIVE
Failure of transpedicular bone-grafting in thoracolumbar burst-fractures has been proven. Possible reasons are insufficient disc-removal and difficult decortication of endplates. Methodical improvements are sought to make the procedure succeed in a sheep-model.


METHODS
12 sheep with posterior instrumentation L4/L6 and transpedicular disremoval L4/L5 underwent auto-grafting. Classical surgical technique was modified by bilateral approach and transpedicular endoscopic control. Animals were sacrificed 8 weeks p.op. For evaluation, radiology, histology, histomorphometry, and fluorochrome-analysis were employed.


RESULTS
10 animals could be evaluated. All revealed sufficient disc-removal and decortication with autograft-impaction into the lower vertebra L4. Main restoration took place before week 4 p.op. Fusion rate was 1/10. For 9/10 animals, defects in the disc-space were filled with metaplastic chondral-tissue; autograft was almost entirely resorbed.


CONCLUSIONS
Reason for failure of the method seems to be the insufficient primary stability of the posterior instrumentation, since satisfactory disc-removal and decortication alone cannot successfully modify the method.
Blattert
T R
TR
Unfall- und Wiederherstellungschirurgie der Chirurgischen Universitätsklinik Würzbug, Josef-Schneider-Strasse 2, 97080 Würzburg. blattert@chirurgie.uni-wuerzburg.de
Delling
G
G
Weckbach
A
A
D000818:Animals; D016025:Bone Transplantation / Q000295:instrumentation* / Q000473:pathology; D019723:Endoscopes; D005260:Female; D017102:Fracture Healing / Q000502:physiology; D018460:Fractures, Comminuted / Q000000981:diagnostic imaging / Q000601:surgery*; D007091:Image Processing, Computer-Assisted; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D016348:Osseointegration / Q000502:physiology; D012756:Sheep; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation*; D014057:Tomography, X-Ray Computed; D017211:Treatment Failure