Biomechanics Study Results Of Unilateral Facetectomy On Lumbar Spinal Stability

Lumbar instability caused by low back pain is the influence of humannormal life and work of common and frequently-occurring diseases.According to foreign reports in western countries about50%of adults havethe risk of low back pain in about half of the need for treatment. Since Mixtand Bar (1934) first proposed the prolapse of lumbar intervertebral disc sincehalf a century on low back pain in people know more and more perfect,profound and rich especially because of degeneration caused by lumbardisease are being increasingly recognized and established relatively perfectmeans of diagnosis and treatment clinical observation showed: at least30%ofthe patients with low back pain symptoms associated with lumbar instability isdirectly related to its etiology, mostly caused by degeneration. In clinical work,we often encounter a lumbar disease patients, and some patients needoperation treatment, which inevitably to the lumbar spine anatomical structureto cause certain effect, to a certain extent caused by the local instability, thelamina, facet joints, ligaments resection range of partial report, resectionextent number determines whether the application of intraoperative internalfixation to maintain the stability of the lumbar spine. This prompted us tofurther understand the surgical operation of lumbar, lumbar biomechanicalchanges, provide theoretical basis to clinical practice.Objective: To investigate the spinal unilateral facet joint resection andafter complete resection, impact on the stability of the spine biomechanicalsituation.Method: Choose6adult fresh cadaveric spine, age of about24-47yearsold, average32.9years old, made of4/5lumbar functional spinal unit (FSU),divided into three groups, all eliminate lumbar muscle tissue surrounding,ligamentous articular capsule structure, specimen ends with self-curing denture powder (for the major components of methyl methacrylate)embedding fixing, maintain both ends of parallel, clamp, experiments inphysical damage cases, experimental group and experimental sequence is asfollows: A group, normal control group; group B, simulated operationresection for unilateral (left) facet, range of less than1/2; group C, simulatedoperation for left facet, range greater than1/2; with the3-D spine motion testmachine to measure FSU three point bending (flexion, extension,compression) left lateral bending and lateral rotation activity displacementchange situation, recording data, and the result of measurement usingstatistical analysis.Results: In the lumbar spine flexion process, unilateral facetectomyeither greater or less than1/2compared with the normal group showed nosignificant difference (P>0.05), on the left and right lateral bendingmovements, unilateral facetectomy is less than1/2, compared with the normalgroup, P>0.05, not statistically significant; while in facetectomy is greaterthan1/2, P <0.05, with statistical significance; on the left and the right rotarymotion, facet joint resection of less than1/2of the group and normal grouphad no significant difference, P>0.05, when the resection range greater than1/2, P <0.05. In the process of movement, when the facet of the resectionrange of less than1/2, lumbar flexion, extension, lateral bending and lateralrotation range of motion is affected certainly, but without statisticalsignificance, when the resection range greater than1/2, lumbar flexion,extension range is affected certainly, no statistical significance, left and rightlateral bending and lateral rotation, there was significant difference, promptexcessive resection of unilateral zygapophysial joints may affect lumbarscoliosis and axial rotation ability, cause lumbar instability.Conclusion: By the experiment of the lumbar spine three point bending,stretching, lateral bending and axial rotation around about experimental reflectbiomechanical data indicate that: unilateral facetectomy lumbar postoperative,resection extent to a certain extent in the lumbar spine biomechanical stability,resection range of less than1/2, had no significant effect, if greater than1in2, lumbar local stability is destroyed, mainly in the FSU lateral bending androtation range of motion than the articular resection of anterior increasedsignificantly, biomechanical stability decreased obviously.