Objective To assess the outcomes of pedicle subtration osteotomy and short-segment pedicle screw internal fixation in kyphosisdeformity. Methods From June 2001 to November 2003, 16 cases of kyphosis deformity were treated with pedicle subtration osteotomy and short-segment pedicle screw internal fixation, including 11 males and 5 females and aging 24-51 years. The kyphosis deformity was caused by ankylosing spondylitis in 12 cases, old lumbothoracic fracturedislocation in 2 cases, and vertebral dysplasia in 2 cases. The disease course was 7-25 years with an average of 12.8years. The whole spine radiographs were taken pre-and postoperatively. The sagittal balance was assessed by measuring thoracic kyphosis angle, lumbar lordosis angle, acrohorizontal angle and distance between posterosuperior point of S1and the vertical line. The clinical outcomes were assessed by Bridwell-Dewald scale for spinal disorders. Results The mean follow-up period was25.6 months. The mean bleeding was 1 100 ml. Satisfactory bone graft healing was achieved at final follow-up. Complications were paralytic intestinal obstruction in 1 case, dura laceration in 1 case, and temporary lower limb paralysis in 2 cases. Final follow-up radiograph showed an increase in lumbar lordosis angle from 9.6±16.4° to 42.6±14.3°(P＜0.05), whereas thoracic kyphosis angle remained relative stable. The distance between posterosuperior point of S1 and the vertical line was decreased from 97.5±45.6 mm to 10.7±9.6 mm(P＜0.05). Satisfactory clinical outcome was achieved by evaluating the changes of pain, social and working status. Conclusion Pedicle subtraction osteotomy and short-segment pedicle screw internal fixation is effective for correction of kyphosis deformity.
目的 探讨经伤椎椎弓根螺钉内固定治疗胸腰椎骨折的临床疗效。 方法 2008年5月－2010年12月，选择38例胸腰椎骨折患者，采用椎弓根螺钉固定伤椎及相邻上下椎体。其中男28例，女10例；年龄21～65岁，平均36.5岁。骨折部位：胸8 1例，胸9 2例，胸10 4例，胸11 8例，胸12 7例，腰1 10例，腰2 4例，腰3 2例。受伤至手术时间3～7 d，平均4.5 d。对患者手术前后椎体高度、矢状面后凸Cobb角、神经功能Frankel分级变化等指标进行测量并随访。 结果 术后患者切口均Ⅰ期愈合。38例获随访12～18个月，平均15个月。骨折均获得骨性融合，无钉棒断裂、无死亡或神经损伤加重患者。术后神经功能Frankel分级较术前有明显改善（P＜0.05）。术后X线片复查示伤椎高度恢复达90%以上，外形正常；CT复查示椎管内有效矢状径恢复满意，椎管前方无明显骨性压迫，伤椎椎体骨愈合良好。术后1、12个月时伤椎前、后缘高度及后凸Cobb角均较术前显著改善（P＜0.05）；术后12个月随访椎体高度无丢失。 结论 经伤椎椎弓根钉复位、减压、内固定治疗胸腰椎骨折具有创伤小、固定节段少、脊柱稳定性好、能有效矫正及预防脊柱后凸畸形等优点。
OBJECTIVE: To review the anatomic character of lower cervical pedicle, the placement and the biomechanical stability of the cervical pedicle screw fixation, the clinical application and the complication caused by fixation. METHODS: The literature concerned the cervical pedicle screw fixation in recent years were extensively reviewed. RESULTS: The cervical pedicle screw fixation can be widely used in the lower cervical spine instability according to the anatomic character of lower cervical pedicle, and the good biomechanical stability of the cervical pedicle screw fixation, and the complication can be controlled. CONCLUSION: The cervical pedicle screw fixation is an effective internal fixation for the lower cervical spine instability.
ObjectiveTo investigate the effectiveness of debridement and single-incision vertebral screw-rod fixation combined with pedicle screw-rod fixation and autograft bone fusion in treatment of thoracolumbar tuberculosis. MethodsBetween January 2008 and October 2010, 22 patients with thoracolumbar tuberculosis were treated by debridement and single-incision vertebral screw-rod fixation combined with pedicle screw-rod fixation and autograft bone fusion, and were given anti-tuberculosis therapy after operation. Of 22 patients, 14 were male and 8 were female with an average age of 42 years (range, 18-66 years). The disease duration was 2-16 months (mean, 6 months). Sixteen double-segment lesions included T7, 8 in 3 cases, T8, 9 in 1 case, T9, 10 in 3 cases, T11, 12 in 2 cases, L1, 2 in 4 cases, and L3, 4 in 3 cases; 6 three-segment lesions included T7-9 in 2 cases, T11-L1 in 1 case, and L2-4 in 3 cases. Preoperative visual analogue scale (VAS) score was 7.50 ± 0.63. According to Frankel classification of America Spinal Injury Association (ASIA), 2 cases were rated as grade B, 4 cases as grade C, 9 cases as grade D, and 7 cases as grade E. ResultsTwenty-two patients were followed up 15-36 months (mean, 25.2 months). Wound infection occurred in 1 case and was cured after corresponding treatment; incision healed by first intention in other patients. No loosening or breakage of internal fixator was found; the patients had no deteriorations in spinal cord injury or cerebrospinal fluid leakage. X-ray films and CT showed obvious bone fusion in the intervertebral space. The time of bone fusion was 3-6 months (mean, 5.2 months). The erythrocyte sedimentation rate after operation was significantly lower than that before operation (P lt; 0.05). The VAS scores were significantly improved to 2.90 ± 1.00 at 2 weeks after operation and 2.60 ± 0.81 at last follow-up (P lt; 0.05). At last follow-up, nerve function was significantly improved. According to Frankel classification, 2 cases were rated as grade C, 5 cases as grade D, and 15 cases as grade E. ConclusionSingle-incision vertebral screw-rod fixation combined with pedicle screw-rod fixation for thoracolumbar tuberculosis is a stable and minimally invasive method. However, the long-term effectiveness need further follow-up.
Objective To review the progress of the pedicle screw augmentation technique by bone cement. Methods Recent literature about the pedicle screw augmentation technique by bone cement was reviewed and analysed. The characters were summarized. Results Pedicle augmentation technique includes the augmentation of ordinary solid pedicle screw and hollow pedicle screw. Both types could increase the fixation strength and gain satisfactory clinical results. Bone cement leakage had a certain incidence rate, but most of cases were asymptom. Conclusion Bone cement augmentation of pedicle screw is an effective and safe internal fixation for poor bone condition.
Objective To evaluate the effectiveness of posterior unilateral pedicle screw fixation plus lumbar interbody fusion in treatment of degenerative lumbar instability. Methods Between February 2008 and December 2011, 33 patients with degenerative lumbar instability were treated with posterior unilateral pedicle screw fixation plus lumbar interbody fusion, including 14 cases of lumbar disc protrusion with instability, 15 cases of lumbar spinal stenosis with instability, 3 recurrent cases of lumbar disc protrusion at 1 year after discectomy, and 1 case of extreme lateral lumbar disc protrusion. There were 20 males and 13 females with an average age of 47.2 years (range, 39-75 years). The average disease duration was 12.8 months (range, 6-25 months). Single-segment-fixation was performed in 28 cases (L4, 5 in 21 cases, L5, S1 in 6 cases, and L5, 6 in 1 case), and double-segment-fixation was performed in 5 cases (L3, 4 and L4, 5). The clinical results were evaluated by using Oswestry disability index (ODI) and modified Japanese Orthopaedic Association (JOA) score for low back pain. Results Infection occurred in 1 case, and was cured after dressing change; primary healing was obtained in the other patients. Thirty-one patients were followed up 32.3 months on average (range, 15-53 months). Cage displacement occurred in 1 case who received bilateral pedicle screw fixation plus lumbar interbody fusion; no screw breaking, Cage displacement, or pseudoarthrosis was observed in the others. X-ray films showed bone fusion in the other patients except 1 case of bone fusion failure. ODI and JOA score at last follow-up were significantly improved when compared with the ones before operation and at 2 weeks after operation (P lt; 0.05); the improvement rates were 74.0% ± 10.1% and 83.6% ± 9.4%, respectively. Conclusion Posterior unilateral pedicle screw fixation plus lumbar interbody fusion is an effective and reliable method for patients with degenerative lumbar instability because it has the advantages of simple operation and less trauma.
Objective To biomechanically compare the maximum pull-out strengths among two pedicle screws and three salvage techniques using poly methylmethacrylate (PMMA) augmentation in osteoporotic sacrum, and to determine which PMMA augmentation technique could serve as the salvage fixation for loosening sacral pedicle screws. Methods Eleven sacra were harvested from fresh adult donated cadavers, aged from 66 to 83 years (average 74.4 years) and included 5 men and 6 women. Radiography was used to exclude sacra that showed tumor or inflammatory or any other anatomic abnormal ities. Following the measurement of bone mineral density, five sacral screw fixations were sequentially establ ished on the same sacrum as follows: unicortical pedicle screw (group A), bicortical pedicle screw (group B), unicortical pedicle screw with the traditional PMMA augmentation (group C), ala screw with the traditional PMMA augmentation (group D), and ala screw with a kyphoplasty-assisted PMMA augmentation technique (group E). According to the sequence above, the axial pull-out test of each screw was conducted on a MTS-858 material testing machine. The maximum pull-out forces were measured and compared. The morphologies of PMMA augmented screws after being pulled-out were also inspected. Results The average bone mineral density of 11 osteoporotic specimens was (0.71 ± 0.08) g/cm2 . By observation of the pull-out screws, groups C, D, E showed perfect bonding with PMMA, and group E bonded more PMMA than groups C and D. The maximum pull-out forces of groups A, B, C, D, and E were (508 ± 128), (685 ± 126), (846 ± 230), (543 ± 121), and (702 ± 144) N, respectively. The maximum pull-out strength was significantly higher in groups B, C, and E than in groups A and D (P lt; 0.05), and in group C than in groups B and E (P lt; 0.05). There was no significant difference in pull-out strength between groups A and D, and between groups B and E (P gt; 0.05). Conclusion For sacral screw fixation of osteoporotic patients with bone mineral density more than 0.7 g/cm2, bicortical pedicle screw could acquire significantly higher fixation strength than the unicortical. Once the loosening of pedicle screw occurs, the traditional PMMA augmentation or ala screw with kyphoplasty-assisted PMMA augmentation may serve as a suitable salvage technique.
ObjectiveTo investigate reliability and short-term effectiveness of axis laminar screws for reducible atlantoaxial dislocation (RAAD).MethodsA clinical data of 41 patients with RAAD who were admitted between February 2013 and February 2018 and met the inclusion criteria was retrospectively analyzed. The atlases in all patients were fixated by lateral mass screws, and the axes were fixed by laminar screws in 13 cases (LS group) and by pedicle screws in 28 cases (PS group). There was no significant difference in gender, age, and preoperative Japanese Orthopedic Association (JOA) score between the two groups (P>0.05). The effectiveness was estimated by post-operative JOA score; and the accuracy of the axis screw, atlantoaxial bone graft fusion, and the fixation stability were examined by X-ray film and CT.ResultsAll incisions healed by first intention. All patients were followed up 12-17 months (mean, 13.8 months) in LS group and 12-20 months (mean 14.1 months) in PS group, and the difference in follow-up time was not significant (Z=−0.704, P=0.482). At last follow-up, JOA scores were 13.9±1.6 in LS group and 14.3±1.8 in PS group, which significantly improved when compared with the pre-operative scores in the two groups (t=−9.033, P=0.000; t=−15.835, P=0.000); while no significant difference was found between the two groups (t=−0.630, P=0.532). Twenty-five screws of 26 screws in LS group and 54 screws of 56 screws in PS group were implanted accurately, with no significant difference in the accuracy of the axis screw between the two groups (Z=−0.061, P=0.951). All patients obtained atlantoaxial bone graft fusion, except 1 case in PS group. There was no significant difference in the atlantoaxial bone graft fusion between the two groups (Z=−0.681, P=0.496).ConclusionFor RAAD, Axis laminar screws can maintain the atlantoaxial primary stability and had a good short-term effectiveness. So, it could be an alternative and reliable technique for axis screw.
ObjectiveTo explore the efficacy of percutaneous pedicle screw internal fixation and minimally invasive lateral small incisions lesion debridement and bone graft fusion via dilated channels in the treatment of lumbar tuberculosis.MethodsThe clinical data of 22 cases of lumbar tuberculosis treated with percutaneous pedicle screw internal fixation combined with dilated channels with minimally invasive lateral small incision lesion debridement and bone graft fusion between January 2016 and June 2018 were retrospectively analyzed. There were 12 males and 10 females, with an average age of 47.5 years (range, 22-75 years). The affected segments were L2, 3 in 5 cases, L3, 4 in 8 cases, and L4, 5 in 9 cases, with an average disease duration of 8.6 months (range, 4-14 months). Preoperative neurological function was classified according to the American Spinal Injury Association (ASIA), with 3 cases of grade C, 9 cases of grade D, and 10 cases of grade E. The operation time, intraoperative blood loss, and postoperative complications were recorded. At preoperation, 3 months after operation, and last follow-up, the C reactive protein (CRP) and erythrocyte sedimen- tation rate (ESR) were tested to evaluate tuberculosis control; the pain visual analogue scale (VAS) score was used to evaluate the recovery of pain, and the Oswestry disability index (ODI) was used to evaluate the function recovery of the patient’s lower back; the kyphosis Cobb angle was measured, and the loss of Cobb angle (the difference between the Cobb angle at last follow-up and 3 months after operation) was calculated. At last follow-up, the ASIA classification was used to evaluate the recovery of neurological function, and the effectiveness was evaluated according to the modified MacNab standard.ResultsThe operation time was 110-148 minutes (mean, 132.8 minutes) and the intraoperative blood loss was 70-110 mL (mean, 89.9 mL). Two patients experienced fat liquefaction of the incision and delayed healing; the incisions of the remaining patients healed by first intention. All patients were followed up 18-24 months, with an average of 21.3 months. All bone grafts achieved osseous fusion, the pedicle screws were fixed in reliable positions, without loosening, displacement, or broken rods. There was no recurrence of tuberculosis. The ESR, CRP, VAS scores, ODI scores, and kyphosis Cobb angle of the affected segment at 3 months after operation and last follow-up were significantly improved (P<0.05); there were no significant differences between at last follow-up and 3 months after operation (P>0.05), and the loss of Cobb angle was (0.6±0.5)°. The patient’s neurological function recovered significantly. At last follow-up, the ASIA grades were classified into 1 case with grade C, 1 case with grade D, and 20 cases with grade E, which were significantly improved when compared with preoperative grading (Z=−3.066, P=0.002). According to the modified MacNab standard, 16 cases were excellent, 3 cases were good, 2 cases were fair, and 1 case was poor. The excellent and good rate was 86.4%.ConclusionPercutaneous pedicle screw internal fixation combined with dilated channels with minimally invasive lateral small incisions lesion debridement and bone graft fusion has the advantages of less bleeding, less trauma, and faster recovery, which is safe and effective in the treatment of lumbar tuberculosis.