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LUMBAR INSTABILITY SURGICAL TREATMENT WITHOUT FUSION: SOFT SYSTEM STABILIZATION

  • GRAF H

J Turk Spinal Surg 1991;2(4):132-140

The existence of intervertebral lumbar instability is now well established but the defı'nition is stili not celar. From that we understand why the diagnostic is sometimes ignore or believe without sufficient proof. The treatment pro-posed is often insufficient or excessive. The author proposes different tests for a better understanding of instability. On bending and flexion/extension X rays, with the help of a microcomputer we are able to measure the shear de-formity of a disk. On M.R.I. documents bony fatty degeneration image in subchondral bone seems to be correiated with F.S.U. abnormai movements. None of these signs are pathognomonic. To understand in 3D the F.S.U. normal and abnormai movements is fundamental. This is why lateral or A. P. approach of the spinal uit is frequently insufficient. Morever the 3D analysis leads us to understand that intervertebral movement is complex corresponding to macro, micro and coupled motion. Pathology will desorganize this complex situation in a subtil way vvhich makes dificult an easy diagnostic. The autorproposes the C. T. Twist-Test to analyse the horizontal movement be-tween vertebrae. So doing the facet decoaptation when twisting can be observed adding the third dimension to the analysis. Finaly a direct in vivo (O.R.) measurement is proposed with the help of a measurer adapted on pedicular screws. The proposed surgical treatment needs pedicular implants which are linked together by polyester thread-ed bands. The device maintains the two vertebrae in extension which in stabilizing. The posterior pre-stress so generated is calculated betvveen 5 to 10 kilogrammes. During the first follow-up (2-3 months) a progressive visco-elastic adaptation of the remaining disk will take place and at the same time a creep of the band can be observed (15 %) so that a new amplitude of some degrees in F.S.U. movement can ble measured in the extension area. This method has been used for more than three years as a surgical treatment in low backpain secondary to instability. DDD, spondylo 1-2, spinal stenosis, disk recurrence, and upper level instability are good indications. The author proposes an adaptated therapeutic response to the wide variety of pathologic problems caused by lumbar disk degeneration.

Keywords: Lumbar spine - İnstability - Surgical stabilization - !Without fusion - C.T. Twist-Test - Bands - Pedicular implants.