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BACKGROUND:As a leading technique in the treatment of primary stenosis by posterior spinal endoscopy through unilateral approach and bilateral decompression using single channel endoscopy,the long-term efficacy needs to be further observed.There are few reports on the scope of intraoperative resection and few relevant studies on biomechanics and finite element analysis. OBJECTIVE:A three-dimensional finite element model was established to evaluate the effects of bilateral lumbar canal decompression under a one-hole split endoscope on lumbar range of motion and intradiscal pressure,to provide suggestions for clinical operation and theoretical basis for further clinical research. METHODS:A complete L3-L5 vertebral body model was reconstructed by CT images of nine healthy volunteers,which was used as the preoperative model M1.The simulated surgical resection range of L4-L5 was performed,and 1/4,1/3 and 1/2 of bilateral facet joints were removed respectively to obtain models M2,M3 and M4.The range of motion and the maximum Von Mises stress of the four models were compared in the six directions of forward bending,backward extension,left and right bending,and left and right rotation. RESULTS AND CONCLUSION:(1)The L3-L5 finite element model established in this study was effective,and the range of motion was within the range of previous solid studies under six motion states.(2)Compared with the M1 model,the L4-L5 lumbar spine range of motion increased with the increase of resection range in M2 with M3 and M4 models under forward bending,left and right bending and left and right rotation loading,and the difference was significant(P＜0.05).Under posterior extension loading,there was no significant difference in lumbar range of motion between M1 and M2(P＞0.05),but there was a significant difference of M1,M3 and M4(P＜0.05).(3)The range of motion of the L3-L4 lumbar spine had no significant change with the increase of bilateral facet arthrotomy(P＞0.05).(4)There was a significant difference in the maximum value of L4-L5 Von Mises between M1 and M2(P＜0.05),and there was a significant difference in the maximum value of L4-L5 Von Mises between M1 and M3,M4(P＜0.01),and the maximum value of L4-L5 lumbar von Mises increased with the increasing range of bilateral facet joint resection.Resection of more than 1/3 was particularly obvious.(5)The maximum value of Von Mises in the L3-L4 lumbar spine was increased with the increase of the resection range under forward bending,left and right bending and left and right rotation loading and the difference was significant(P＜0.05).(6)The results exhibited that the L4-L5 lumbar motion and intervertebral disc pressure increased with the increase of the excision range.Intervertebral disc pressure at L3-L4 increased with the increased extent of excision,but the lumbar range of motion was not significantly affected.In conclusion,the stability of the operative segment may be affected by the increase in the scope of facet joint resection.Although the immediate stability of adjacent segments is not affected,it may accelerate disc degeneration.

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OBJECTIVE@#To compare the effectiveness of posterolateral approach lumbar interbody fusion assisted by one-hole split endoscope (OSE) and traditional posterior lumbar interbody fusion (PLIF) in the treatment of L4, 5 degenerative lumbar spondylolisthesis (DLS).@*METHODS@#The clinical data of 58 patients with DLS who met the selection criteria admitted between February 2020 and March 2022 were retrospectively analyzed, of which 26 were treated with OSE-assisted posterolateral approach lumbar interbody fusion (OSE group) and 32 were treated with PLIF (PLIF group). There was no significant difference between the two groups in terms of gender, age, body mass index, Meyerding grade, lower limb symptom side, decompression side, stenosis type, and preoperative low back pain visual analogue scale (VAS) score, leg pain VAS score, Oswestry disability index (ODI), and the height of the anterior and posterior margins of the intervertebral space (P>0.05). The operation time, intraoperative blood loss, postoperative hospital stay, and complications were compared between the two groups. The low back pain and leg pain VAS scores and ODI before operation, at 1 month, 6 months after operation, and last follow-up, the height of anterior and posterior margins of the intervertebral space before operation, at 6 months after operation, and last follow-up, the modified MacNab criteria at last follow-up after operation were used to evaluate the effectiveness; and the Bridwell method at last follow-up was used to evaluate the interbody fusion.@*RESULTS@#Both groups successfully completed the operation. Compared with the PLIF group, the OSE group showed a decrease in intraoperative blood loss and postoperative hospital stay, but an increase in operation time, with significant differences (P<0.05). In the OSE group, no complication such as nerve root injury and thecal sac tear occurred; in the PLIF group, there were 1 case of thecal sac tear and 1 case of epidural hematoma, which were cured after conservative management. Both groups of patients were followed up 13-20 months with an average of 15.5 months. There was no complication such as loosening, sinking, or displacement of the fusion cage. The low back pain and leg pain VAS scores, ODI, and the height of anterior and posterior margins of the intervertebral space at each time point after operation in both groups were significantly improved when compared with those before operation (P<0.05). Except for the VAS score of lower back pain in the OSE group being significantly better than that in the PLIF group at 1 month after operation (P<0.05), there was no significant difference in all indicators between the two groups at all other time points (P>0.05). At last follow-up, both groups achieved bone fusion, and there was no significant difference in Bridwell interbody fusion and modified MacNab standard evaluation between the two groups (P>0.05).@*CONCLUSION@#OSE-assisted posterolateral approach lumbar interbody fusion for L4, 5 DLS, although the operation time is relatively long, but the postoperative hospitalization stay is short, the complications are few, the operation is safe and effective, and the early effectiveness is satisfactory.

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BACKGROUND:It remains controversial about the clinical outcomes of bone fil ing mesh containers (BFMCs) and percutaneous kyphoplasty (PKP) in pain relief, kyphosis correction, vertebral height restoration and reduction of cement leakage. OBJECTIVE:To compare the clinical outcomes of BFMCs and PKP for osteoporotic vertebral compressive fracture. METHODS:A total of 90 patients with osteoporotic vertebral compressive fracture were equivalently randomized into two groups, fol owed by treated with BFMCs or PKP, respectively. During a more than 3-month fol ow-up, pain relief, kyphotic angle, the vertebral height and cement leakage were observed in the two groups to assess the therapeutic effects. RESULTS AND CONCLUSION:Pain in al patients was relieved at 24 hours after operation. There was no significant difference in pain relief between two groups (P>0.05). PKP was more effective to restore the vertebral height (P<0.05), while BMCFs significantly reduced the leakage rate of bone cement (P<0.05). These results suggest that BFMCs and PKP have their own advantages in the treatment of osteoporotic vertebral compressive fracture, but both exert analgesic effects.

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BACKGROUND:At present, there are many researches about repairing articular cartilage defects. In particular, the microfracture technique has been widely used. OBJECTIVE:To observe recovery of knee joint motor function and morphological changes in tissue repair during articular cartilage defects with different directions (coronal position and sagittal position). METHODS:Articular cartilage fracture models with 2 mm-thick medial femoral condyles of rabbit knee joint were established. According to incision directions, models were assigned to coronal and sagittal groups. At 5, 10 and 20 weeks after model induction, general observation was performed. Specimens were sliced into paraffin sections, and subjected to hematoxylin-eosin staining and col agen staining. Tissue repair at the articular cartilage defects was observed using optical microscope and immunohistochemical method. After model induction, range of motion of rabbit joints was regularly examined in the two groups.RESULTS AND CONCLUSION:A white line was seen across the femoral condyles at defects in the two groups. Articular surface at defect repair was at the level of in situ cartilage, and reached a bone union. Knee joint treated by operation did not affect function. Under light microscope, partial reconstruction of subchondral bone was seen in the two groups, mainly fibrocartilage repair. The level of bony remodeling was lower than tidal line of adjacent in situ cartilage. Immunohistochemical method exhibited that type I col agen staining gradual y reduced at defects of specimens, but type II col agen staining gradual y increased. These results suggested that there was no significant difference in the recovery of motor function of knee joint and the repair of articular cartilage with different directions (coronal and sagittal position).