ABSTRACT
Objective To study the feasibility and safety of total en bloc spondylectomy (TES) for bone tumors of the fourth lumbar spine and evaluate the clinical outcomes.Methods From March 2011 to December 2013,21 patients undergone total en bloc spondylectomy in posterior-only approach were retrospectively reviewed.The patients included 9 males and 12 females,with a mean age of 47.1± 15.6 years old (range,15-71 years old).This series included 12 cases of primary bone tumors and 9 cases of solitary metastases.Preoperative evaluation according to clinical,imaging and pathologic features was performed meticulously to select patients.The length of surgery,estimated blood loss,surgical margins,instrumentation failure,perioperative complications,Frankel scale,visual analogue scale (VAS) for pain,local control rate and overall survival were reviewed and analyzed.Results Total en bloc spondylectomy was performed successfully in all patients.Average operative time and estimated blood loss were 297.6±44.6 min (range,225-420 min) and 2 247.1±904.5 ml (range,900-4100 ml),respectively.The mean follow-up time was 50.4± 17.1 mons (range,24-79 mons).All patients encountered nerve roots stretch and 5 patients (23.8％) showed lower extremeties neurological dysfunction.All of them improved in 2-4 weeks postoperatively and recovered completely at 6-month follow -up.Cerebrospinal fluid leak was found in 4 patients (19.0％).The VAS score was 1.5±1.4 at post-operation,which was significantly lower than the 6.2± 1.6 in average at operation (P=0.008).Three patients with metastatic tumors died during the follow-up.Titanium mesh cage subsidence was observed in 7 patients (33.3％).No implant failure was occurred during the follow-up.Conclusion Total en bloc spondylectomy for tumors of the fourth lumbar spine in a posterior-only approach is feasible.However,there are many intraoperative neurological complications and the indications for TES are extremely limited.
ABSTRACT
Objective To evaluate the mechanical stability of alternative reconstruction methods after total en bloc spon?dylectomy in the lower lumbar spine. Methods Eight adult fresh cadaveric lumbosacral spines (L1-S1) were adopted. Total en bloc spondylecotmy of the L4 vertebra was performed after intact testing. Four designed reconstruction samples were tested for the range of motion (ROM) of the spine:1) expandable artificial vertebral body and short posterior instrumentation at L3-L5 (SP), 2) ex?pandable artificial vertebral body and short posterior instrumentation with additional anterolateral fixation at L 3-L5 (ASP), 3) ex?pandable artificial vertebral body and multilevel posterior instrumentation at L2-S1 (MP), 4) expandable artificial vertebral body and multilevel posterior instrumentation with additional anterolateral fixation at L2-S1 (AMP). Nondestructive biomechanical test?ing was performed on each construct under loading control. The ROM for each construct was obtained by applying pure moments in flexion, extension, lateral bending, and axial rotation. Results In flexion, extension and lateral bending, the ROM of all the re?constructed constructs significantly decreased compared to the intact. The ROM of specimens with anterolateral fixation was less when compared to the ones without additional fixation. In lateral bending, MP (L:1.87° ± 0.32° , R:1.97° ± 0.33° ), ASP (L:1.89° ± 0.37°, R:2.08°±0.36°) and AMP (L:1.32°±0.29°, R:1.61°±0.33°) provided significantly less ROM than the SP (L:3.14°±0.35°, R:3.44°±0.34°). In axial rotation, the ROM of ASP (L:4.21°±0.58°, R:4.02°±0.59°) and AMP (L:3.56°±0.55°, R:3.52°±0.48°) was significant decreased when compared to the intact state (L: 7.47° ± 1.00° , R:7.57° ± 0.84° ). MP (L:6.33° ± 0.71° , R:5.88° ± 0.62°), ASP and AMP showed significantly less ROM than the short posterior fixation (L:9.28°±1.01°, R:9.48°±0.98°). AMP sig?nificantly decreased the ROM compared to MP. Conclusion After total en bloc spondylectomy of lower lumbar, long segmental fixation provided more stability to the construct than the short one. Compared to posterior fixation, circumferential fixations showed a higher stability. In contrast, multilevel segmental instrumentation with circumferential fixation did not provided more stability than the short constructs.