Article

Pedikuloskopisch assistierte transpedikuläre Spongiosaplastik zur interkorporellen Fusion an der lumbalen Wirbelsäule Eine tierexperimentelle Untersuchung am Schafsmodell

Der Unfallchirurg (Impact Factor: 0.61). 07/2002; 105(8):680-687. DOI: 10.1007/s00113-001-0404-1

ABSTRACT Fragestellung. Das Versagen der transpedikulären Spongiosaplastik bei thorakolumbalen Wirbelfrakturen ist nachgewiesen. Angeschuldigt werden
u. a. unzureichende Bandscheibenausräumung, schwierige Endplattendekortikation und blindes, nur indirekt kontrollierbares
Vorgehen. Methodische Verbesserungen sollen im Tiermodell zum Erfolg führen.

Methodik. An 12 Schafen erfolgten dorsale Instrumentierung L4/L6, transpedikuläre Bandscheibenausräumung L4/L5 und Spongiosaplastik.
Die klassische Operationstechnik wurde methodisch durch bilaterales Vorgehen unter transpedikulärer endoskopischer Kontrolle
(“Pedikuloskopie”) modifiziert. 8 Wochen postoperativ wurden die Tiere getötet, anschließend erfolgte die radiologische, histologische,
histomorphometrische und fluorochromsequenzanalytische Untersuchung.

Ergebnisse. 10 Tiere konnten ausgewertet werden. In allen Fällen waren der Nucleus pulposus zentral entfernt und die vollständige Dekortikation
mit Introduktion der Spongiosa in den kaudalen L4-Anteil gelungen. Das Maximum der Reparationsvorgänge lag vor der 4. Woche.
Die Fusionsrate betrug 1/10. Bei 9/10 war der Bandscheibendefekt von Knorpelmetaplasien ausgefüllt und die Spongiosa weitgehend
resorbiert.

Schlussfolgerungen. Versagensursache der Methode scheint die insuffiziente Primärstabilität der dorsalen Instrumentierung zu sein, da auch ausreichende
Bandscheibenausräumung und Endplattendekortikation nicht zum Erfolg führen.

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.

Method. 12 sheep with posterior instrumentation L4/L6 and transpedicular disc-removal 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.

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