| Objective: To compare clinical effects of lumbar interbody fusion withunilateral pedicle screw fixation and bilateral pedicle screw fixation in treating lumbardegenerative disease. Methods: Form October2006to October2010，sixty cases weretreated with lumbar interbody fusion with unilateral pedicle screw fixation or bilateralpedicle screw fixation, and were divided into two groups according to internal fixationmode. There were28cases of which underwent lumbar interbody fusion with unilateralpedicle screw fixation,16males and12females with an average of48years(range,40-56). The preoperative diagnosis consisted of lumbar disc herniation (n=4), postoperative recurrent lumbar disc herniation (n=6), spinal stenosis (n=6),degenerative lumbar instability (n=8), degenerative spondylolisthesis (n=4). Therewere32cases of which underwent lumbar interbody fusion with bilateral pedicle screwfixation,18males and14females with an average of52years(range,42-67). Thepreoperative diagnosis consisted of lumbar disc herniation (n=5), postoperative recurrentlumbar disc herniation (n=6), spinal stenosis (n=7), degenerative lumbarinstability (n=6), degenerative spondylolisthesis (n=8). Pre-and postoperativescores measured by Oswestry Disability Index (ODI), Visual Analog Scale (VAS), andJOA scores were analyzed and compared between the two groups. Comparison wasconducted between two groups in terms of operation duration, intraoperative blood loss,fusion rates, operative cost, excellence rate, incidence rate of complications. Results:Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) in two groups showedstatistical significance between preoperation and3months,6months（P<0.05. Compared with B group, A group had shorter operation duration, less intraoperative blood loss andlower operative cost,with statistical difference （P<0.05）. No significant difference wasfound between two groups in the fusion rates,excellence rate, incidence rate ofcomplications（P>0.05）.The fusion rate of two groups were92%、94%respectively.Conclusion: Lumbar interbody fusion with unilateral pedicle screw fixation is as effectiveas with bilateral pedicle screw fixation. It is demonstrated that lumbar interbody fusionwith unilateral pedicle screw fixation was an effective and convenient method with littlesurgical trauma as well as a satisfactory method in treating lumbar degenerative disease.But the operation indications must be strictly defined and long-term clinical studies arerequired. Objective: The purpose of this study was to explore the possible causesand incidence of the postoperative back pain in the opposite lumbosacral area. Methods:Form October2008to October2011，thirty consecutive patients (16men and14womenwith age ranged from40to56years) underwent diagonal cage-instrumented lumbarinterbody fusion with unilateral fixation. Pre-and postoperative scores measured byOswestry Disability Index (ODI), Visual Analog Scale (VAS) were analyzed. Fusionstatuses, condition of intervertebral height and opposite facets were investigated withX-ray and CT scans. Results: Oswestry Disability Index (ODI),Visual Analog Scale (VAS)showed statistical significance between peri-operation and3months,6months,12monthspostoperatively(P<0.05). The fusion rates were92%, The clinical results were89%satisfactory, five patients complained recent postoperative back pain in the oppositelumbosacral area.Conclusion: Due attention should pay to the postoperative back painarised from the restore intervertebral height asymmetrically and the opposite facetsdisfunction.The operation indications must be strictly defined and long-term clinicalstudies are required. Objective: To investigate the biomechanical stability of triangleconstruct fixation (TCF). Comparisons were made with conventional pedicle screwfixation. Methods: Three-dimensional finite element models were established bysimulating bilateral pedicle screw fixation (BPSF), unilateral pedicle screw fixation(UPSF), and triangle construct fixation (TCF).500N pre-load was added on the superiorsurface of the L3vertebral body, followed by load of10N·m torque to simulate L4-L5flexion, extension, lateral bending, and axial rotation. The stress changes and distributionsof the three kinds of fixation and cage, the L4-L5angular variation under different loadwere compared and analyzed using software. Results: Both TCF and BPSF were able toachieve more reduction in angular variation compared with UPSF. The pedicle peak stressin UPSF was markedly higher than that in BPSF and TCF. The cage peak stress in theUPSF was higher than that in BPS F and TCF, BPSF was similar toTCF.Conclusion:.Biomechanical stability of the TCF was superior to UPSF, similar to [Objective]: Identify the biomechanical effects of unilateral pedicle screwcombine transfacet pedicle screw fixation (TPSF). Comparisons were made withUPS+TPSF, BPSF and UPSF.[Method]: Three-dimensional finite element models wereestablished by simulating bilateral pedicle screws fixation (BPSF), unilateral pediclescrews fixation (UPSF) and (UPSF+TPSF).500N preload was added on the superiorsurface of the L3vertebral body, followed by load of10N·m torque to simulate L4-L5flexion, extension, lateral bending, and axial rotation. The stress changes and distributionof the three kinds of fixation, the L4-L5angular variation, cage under different load werecompared and analyzed using software.[Result]: The group UPSF+TPSF was able to achieve more reduction in angular variation compared with group UPSF. Group UPSF wasthe least stable in all loading modes and was significantly different than group BPSF inlateral bending. The pedicle peak stress in group UPSF was markedly higher than that ingroup UPSF+TPSF and group BPSF, especially high on left lateral bending and extension,the group UPS+TPSF was higher than the group BPSF. The cage peak stress in the groupUPSF was higher than that in group UPS+TPSF and group BPSF. And group UPS+TPSFwas similar to group BPSF.[Conclusion]: The group UPS+TPSF was superior to groupUPSF. It may offer the potential for percutaneous fixation in order to decrease themorbidity and complications associated with open procedures and decrease costs ofimplants. TPSF can be considered as a good alternative to lumbar posterior stabilizationmethods. Objective: To explore the relationship of the lumbar facets and thecorresponding bony endplate, providing anatomic and radiographic guidelines for safepercutaneous placement of the transfacet pedicle screws.Methods: Twenty normal drycadaveric lumbar vertebra specimens and lumbar spinal radiograph of anteroposterior,lateral views of200adult21-44years old who undergoing physical examination werechosen to research. Depth of the facets in the sagittal and axial plane and ratio of the facetsbeyond the bony end plate were were measured.The relationship of the starting pointrelative to landmarks of the inferior bony endplate was measured. Results: Both inferiorand superior facet heights were14.5mm at L3-L5/S1levels. The percentage of inferiorfacet extending below the L3and L4bony end plates was74%and78%respectively anddecreased at L5to67%. The percentage of superior facet extending above the bony endplate ranged from35%to40%at all levels.Conclusions: The starting point of the percutaneous placement of lumbar transfacetpedicle screw should be centered on the inferior bony endplate in the coronal plane. Objective: To explore the ideal starting point and trajectory forpercutaneous lumbar trans-facet pedicle screws fixation, providing anatomic guidelines forsafe placement of the screws. Methods: Twenty normal dry cadaveric lumbar vertebraspecimens and lumbar spinal radiograph of anteroposterior and lateral views of200adult21-44years old that undergoing physical examination were chosen to research. Linear andangular measurements of the facets including the length, width, depth and degrees ofangulation in the sagittal and axial plane were recorded. Under direct visualization, thesegments were pinned with Boucher technique. The relationship of the starting pointrelative to landmarks of the superior body was measured. Under fluoroscopy, radiographicparameters for ideal starting point and ending point of the pin were determined. Results:There was progressive increase in maximum superior facet depth from L3to S1, with S1being the largest at16mm. Both the inferior and superior facet heights from L3to L5orS1were approximately14.5mm at all levels. The increasingly extroversion angle of facetjoint measuring18°,27°,35°, and44°from L3to S1with caudal progression. The startingpoint in the coronal plane is based on the superior body of the instrumented segment andshould be in line with the the midpoint of the spinous process and the inferior articularprocess edge connection in the medial-lateral direction and in line with the inferior endplate in the cranial-caudal direction.The pin should be laterally angulated approximately15-18°in the axial plane approximately30-35°caudally in the sagittal plane. The pinshould end in the inferolateral quadrant of the pedicle on the AP radiograph and at thepedicle vertebral body junction on the lateral radiograph. Conclusions: The accurateanatomical date of lumbar facet articular acquired by measurement can be used to supportthe percutaneous placement of lumbar transfacet pedicle screw fixation. |
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