Biomechanical And Clinical Study Of Short-segmental 3D Spinal Reconstruction Through One Stage Combined Anterior And Posterior Approach

PartⅠObjective To analyze the biomechanical stability of short-segmental 3D spinalreconstruction through combined anterior and posterior approach.Methods Six adult human lumbar spine specimens were colleted. The L5 vertebralbody was resected and reconstructed with titanium mesh, and posterior short-segmentpedicle instruments was installed at L4 and S1 vertebrae for each specimenrepectively. The stability was measured under flexion, extension and lateral flexionstress with biomechanical machine, and the fatigue stability was tested with 10 000cycle flexion-extension stress.Results The mobility of the specimens was minimal under flexion, extension andlateral flexion stress. There was no significant difference of stiffness between flexionand lateral flexion. The mobility was slightly greater under extension stress thanflexion or lateral flexion stress (P＜0.01). After 10 000 cycle stress, the mobility underextension stress slightly increased, while the position of titanium mesh did notchanged according to the L4 and S1 vertebrae.Conclusion The spinal stability was restored with short-segment 3D reconstruction,with minimal intervertebral mobility under flexion, extension and lateral flexionstress. The position of titanium mesh did not changed significantly after 10 000 cycleflexion-extension stress. The mobility under extension stress increased after cycleloading while that under flexion and lateral flexion stress did not increasedsignificantly.PartⅡObjective To analyze the results of one-stage combined anteroposterior surgery inlateral position for serious thoracolumbar fracture dislocation. Methods A retrospective review was performed for surgically treated thoracolumbarfractures from October 1998 to September 2005. Of all the 192 patients, the 34serious cases were treated with one-stage combined anteroposterior surgery. Therewere 25 males and 9 females, 34.2 years old on the average (ranging from 18 to 56years). Segments involved: T11 in 2 cases, T12 in 5 cases, L1 in 11 cases, L2 in 8cases, L3 in 5 cases, L4 in 2 cases and L4, 5 in 1 case. According to the Classificationof Magerl, there were 12 cases of type A3, 2 cases of B1, 2 cases of B2, 12 cases ofC1, 4 cases of C2 and 2 cases of C3. During the operation the patients were in lateralposition. Laminectomy and pedical screw insertion were performed posteriorly first;anterior corpectomy, reduction and strut graft were accomplished through anadditional anterior approach. The final fixation was finished by clapping the strutgraft with pedical screw system. Operative notes, preoperative and postoperativeneurological status, ASIA scales, radiographs, CT scans, and follow-up records werereviewed.Results All these surgeries were performed successfully without any neurologicaldeterioration. 32 of 34 patients were followed-up for 6 to 60 months (13 months onaverage). Neurological status improved at least 1 ASIA grade in 24 patients withpreoperative incomplete paraplegia. 6 patients complained intercostals nerve injurysymptom which alleviated with conservative treatment. During follow-up, lumbarphysical lordosis was reconstructed and no evident correction loss, pseudoarthrosis orimplant failure was noted.Conclusion One-stage combined anteroposterior surgery can be accomplished in alateral position. It was proved to be an effective treatment for serious thoracolumbarfracture dislocation.