Load bearing capacity of the thoracic spine and the necessity of fusion following modified microdiscectomy: theoretical evaluation and experimental in vitro biomechanical study

  • П. В. Кротенков Department of Neurosurgery Moscow Regional Scientific Research Clinical Institute, Moscow, Russia
  • А. М. Киселев Department of Neurosurgery Moscow Regional Scientific Research Clinical Institute, Moscow, Russia
  • А. В. Кедров Department of Neurosurgery Moscow Regional Scientific Research Clinical Institute, Moscow, Russia
  • Н. С. Гаврюшенко Experimental Research Laboratory Central Institute of Traumatology and Orthopedics, Moscow, Russia
Keywords: biomechanics, thoracic spine, microdiscectomy, load bearing capacity, thoracic disc herniation

Abstract

Objectives: to estimate the need for thoracic spine fusion after modified microdiscectomy on the basis of biomechanical spine concepts of Denis and Benzel, and to perform experimental in vitro cadaveric study to study the thoracic spine load bearing capacity, in flexion and axial loading, in intact state and after microdiscectomy. Methods: seventy two functional spinal units (FSU) (from T4/5, T6/7, T8/9, T10/11 segments) from eighteen human cadavers were tested in three sequential stages. In stage 1 we tested intact specimens (control group) in compressive axial load and compressive-flexural bending load. Stage 2 and 3 included four-level simulated modified microdiscectomy performed on ten human cadavers (5 cadavers on each stage), with subsequent sectioning and testing with compressive axial load (stage 2) and compressive-flexural bending load (stage 3). All specimens were loaded until the registration of the limit of linear elastic behaviour on the load deformation curve. Results: thoracic FSU’s load bearing capacity at the proportional limit, under axial and flexion load, in intact state and after microdiscectomy, showed to be insignificant in all groups (P>0,05). Strength properties for the normal thoracic FSU’s showed modest inter-region (T4/5, T6/7, T8/9 or T10/11 segments) difference, but still insignificant (P>0,05). Conclusions: microdiscectomy in our modification causes minimal loss of in the thoracic FSU. Therefore, fusion or instrumentation procedures are not necessary.

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Published
2007-05-31
How to Cite
Кротенков, П., Киселев, А., Кедров, А., & Гаврюшенко, Н. (2007). Load bearing capacity of the thoracic spine and the necessity of fusion following modified microdiscectomy: theoretical evaluation and experimental in vitro biomechanical study. Bulletin of the International Scientific Surgical Association, 2(2-3), 21-26. Retrieved from http://surgjournal.ru/index.php/BISSA/article/view/192
Section
Original Articles