ObjectiveTo investigate the changes of the opposite structures with the minimally invasive transforaminal lumbar interbody fusion and unilateral fixation.MethodsFrom January 2009 to January 2010,a total of 34 patients with low back pain underwent the minimally invasive transforaminal lumbar interbody fusion and unilateral internal fixation were retrospectively analyzed.Visual analogue scale (VAS) and Japanese Orthopaedic Association(JOA) low back pain scores were used to assess the outcome of the surgery.All patients were followed up for at least 6 months after surgery.The opposite structures of the segments with fusion and unilateral fixation were investigated with CT scans.CT imaging of the patients with opposite low back pain after surgery were analyzed for exploring possible causes of the pain.ResultsThere were significant differences between the pre- and post-operation in VAS and JOA scores(P＜0.01).Four patients met pain in the opposite lumbosacral area after surgery.The CT scans showed that the rebuilding of the lordosis and disc height of the opposite side were more difficult.Rotation could happen in the progress of surgery.For the 4 patients with opposite low back pain after surgery,the insufficiency of the rebuilding of lordosis and disc height of the opposite side,and the rotation between the vertebras were more obvious,and changes were observed in the opposite facet joint on the post-operational CT scan of one patient.Conclusion The minimally invasive transforaminal lumbar interbody fusion and unilateral fixation are effective for patients with low back pain.It's important to pay more attention to the rebuilding of the lordosis and disc height of the opposite side,and the rotation of the vertebras in the surgery.

Objective To investigate the correlation between MR imaging and pathological features of nucleus pulposus degeneration in the lumbar disc, and to provide a reliable evidence to evaluate the nucleus pulposus degeneration by MR imaging relative signal intensity. Methods From January 2001 to December 2001, 91 patients who underwent operative treatment for lumbar disc diseases were recruited for the study, while 4 lumbar fracture patients with no previous low back pain and 2 fresh brain-injury cadavers were recruited for contrast study. Before operation, the relative signal intensity was measured in MRI T2WI images. All 117 specimens were dyed with HE and Alcian blue CEC. The water content was also detected. The correlation between MRI relative signal intensity and chondroitin sulfate index, water content was analyzed with SPSS 10.0 software, the correlation between chondroitin sulfate index and water content was analyzed as well. Results There was significant difference between the above mentioned two groups when MRI relative signal intensity, chondroitin sulfate index and water content was compared. Whereas there was no significant statistical difference when keratin sulfate index was compared between the two groups. MRI relative signal intensity positively correlated with water content and chondroitin sulfate index, and the chondroitin sulfate index positively correlated with water content. Conclusion The MRI relative signal intensity reflects not only the water content, but also the pathological characteristics of nucleus pulposus degeneration. The quantitative classification of relative signal intensity in MRI is a method to identify the grades of nucleus pulposus degeneration.

Objective To investigate the safe directions of screw trajectory in atlas via posterior arch and lateral mass and its clinical significance. Methods Lateral radiographs and CT axial scans of atlases were performed in 30 cases with normal morphology of atlases and axes. The minimal height of posterior arch, the maximum inclination of screw projection relative to sagittal plane, and the maximum medial angle of screw projection relative to axial plane were evaluated radiologically. According to the safe directions obtained radiologically 21 cases of atlantoaxial instability were treated with screw fixation atlas via posterior arch and lateral mass. During operation the influence of screws on surrounding structures was investigated and postoperative neural symptoms were documented also. Preoperative and postoperative radiographs and CT scans of 13 patients were available and some related parameters were measured to evaluate the safety of the screw placements. Results 1) The maximum angle of screw projection to sagittal plane is about 10? cephalad to 6? caudal, with the tendency of increasing maximum angle as the minimal height of posterior arch increases. 2) When the entry point on the posterior arch was switched laterally, the medial angle of screw projection should be adjusted from 0? to 30?, correspondingly. 3) The actual directions of screw trajectory might differ from preoperative ones, but all were in the estimation range. 4) All screws were placed successfully, and the postoperative radiographs and CT scans shows no neural or vascular complications relative to atlantal screws placed in traditional way. Conclusion There is a safe range to insert atlas screw via posterior arch and lateral mass both in sagittal and axial plane.

Objective To demonstrate the histopathological changes of sequestration-type herniated disc, and investigate the related factors of its absorption. Methods 39 tissue samples were surgically removed from 37 patients with sequestration-type lumbar disc herniation. All the tissues were performed with HE stain and immunohistochemical study. In HE stain, the origin of tissue was identified; in immunohistochemical study, anti-CD34 antibody was used for detecting the vascular endothelial cells, and anti-CD68 for macrophages. The sequestration-type lumbar disc was divided into 3 groups according to the content of nucleus pulposus: nucleus pulposus group, nucleus pulposus contained group and non-nucleus pulposus group. The correlation between the extent of angiogenesis and macrophage infiltration and the factor of age, disease duration, origin of sequestrated tissue and imaging features was studied. Results 62% (24/39) of the sequestrated tissues were mainly originated from nucleus pulposus. Granulation tissue with many macrophages around new blood vessels was found in 92%(36/39) of the sequestrated tissues. There was a significant difference of the extent of angiogenesis and macrophage infiltration among these 3 groups in terms of the content of nucleus pulposus group(F=5.663, P=0.008; F=3.604, P=0.038). There was no significant correlation between the extent of angiogenesis and macrophage infiltration and age or disease duration, whereas, a positive significant correlation was found for the size of sequestrated tissue (r=0.342, P=0.033; r=0.440, P=0.005). Furthermore, the extent of angiogenesis and macrophage infiltration was significant when the relative signal intensity of sequestrated tissue on MRI was in 0.30-0.72. Conclusion The origin of sequestration-type herniated disc is mainly from nucleus pulposus, and most of the sequestration tissue can be absorbed in different extent. The extent of spontaneous absorption was mainly depended on the origin of the sequestration tissue, but not the age or disease duration. Predominant absorption is found in bigger size of the sequestration tissue and their relative signal intensity on MRI being 0.30-0.72.

Objective To investigate the radiographic features and surgical approach of severe fixed cervical kyphosis.Methods Seventeen cases of severe fixed cervical kyphosis from January 2007 to January 2012 were studied retrospectively.There were 8 males and 9 females,with an average age of 49.7 years.The etiologies were 3 cases of infection,3 cases of degeneration,3 cases of neurofibromatosis,3 cases of prior laminectomy,2 cases of idiopathic,2 cases of trauma and 1 case of neuromuscular disease.The average length of kyphosis was 4.3 ± 1.2 segments.All patients complained of severe neck pain (visual analogue scale,VAS,7.6±1.5) or progressive cervical kyphosis.There were 4 cases with myelopathy,2 with radiculopathy,3 with difficulty of forward gaze and 1 with difficulty of swallowing.All patients were underwent dynamic flexion-extension radiographs and traction views.CT scans were carried out to identify the sites of fixed kyphosis.Continuous traction was performed after general anesthesia,and the surgical approach was decided according to spinal cord compression,length of kyphosis and the cause of fixed kyphosis.Surgical outcomes were assessed in terms of correction of Cobb angle and Odom criteria.Results All patients were followed-up for 2 to 5 years.According to the CT scans,the sites of fixed kyphosis were identified:anterior bony ankylosis in 7 cases,posterior in 6 cases and both anterior and posterior in 4 cases.The surgical approach were as following:anterior only in 4 cases,posterior only in 2 cases,anterior-posterior in 5 cases,posterior-anterior in 3 cases,anterior-posterior-anterior in 1 case and posterior-anterior-posterior in 2 cases.The Cobb angle was corrected from 49.3°± 14.6° preoperation to 2.1 °±6.8° at the latest follow-up,with an average correction of 47.2°.According to Odom criteria,there were 7 excellent outcome,8 good,2 fair and none poor outcome.Revision surgery was performed in 1 case due to proximal junctional kyphosis.At the latest follow-up,bony fusion was found in all patients.Conclusion CT scan is helpful in identifying the cause of fixed kyphosis.The surgical approach of fixed cervical kyphosis is decided by spinal cord compression,length of kyphosis and cause of fixed kyphosis.Anterior approach is suitable for anterior ankylosis,posterior approach for posterior ankylosis,combined approach for both anterior and posterior ankylosis.

ObjectiveTo investigate the efficacy of percutaneous pedicle screw fixation combined with transpedicular interbody bone grafting for the treatment of thoracolumbar fractures.MethodsA total of 20 patients with thoracolumbar fractures (type A,load sharing ≥7,without neurological deficit) underwent percutaneous pedicle screw fixation of Sextant systems combined with transpedicular interbody bone grafting were retrospectively studied.The perioperative parameters,radiographic and clinical outcomes were compared with another 20 patients underwent traditional short-segment pedicle screw fixation combined with transpedicular interbody bone grafting.All patients were followed up for at least 2 years after surgery.ResultsThere were no significant differences between the two groups in sex,age,injury to operation interval,and load sharing scores.However,there were significant differences between the two groups in operating time and blood loss(P＜0.05).The vertebral body height and kyphosis angle were corrected significantly after surgery (P＜O.05),however,the recovery of the vertebral body height and kypbosis angle were reduced significantly one year after surgery in both groups (P＜0.05).At the final follow-up,there were no significant progressive losses of the recovery of the vertebral body height and kyphosis angle,as compared with that of one year after surgery in two groups.There were no significant differences in radiographic parameters and the clinical outcomes between the two groups,even though less radiographic correction and better clinical outcomes were found in percutaneous techniques.ConclusionShort-segment pedicle screw fixation with transpedicular grafting remains a reliable surgical method for the treatment of severe thoracolumbar fractures without neurological deficit.Percutaneous pedicle screw fixation proved to be an effective method with the advantages of minimal invasiveness and less blood loss.

Objective To investigate the effect of percutaneous lordorizing screws fixation for correcting kyphosis in thoracolumbar burst fractures and treatment strategies.Methods A retrospective case control study was designed to analyze data of 97 patients with single-level thoracolumbar burst fractures without neurological deficits undergone percutaneous lordorizing screw fixation from April 2010 to March 2015.According to the different surgical procedures,the patients were divided into Group A (percutaneous transpedicle fixation,n =47) and Group B (percutaneous transpedicle fixation combine lordorizing screw fixation,n =50).Each group was subdivided based on the preoperative segmental kyphosis:Group A consisted subgroups A1 (kyphosis angle≤ 10°,n =11),A2 (kyphosis angle between 10° and 20°,n =20) and A3 (kyphosis angle ≥ 20°,n =16),and Group B consisted of subgroups B1 (kyphosis angle ≤ 10°,n =16),B2 (kyphosis angle between 10° and 20°,n =16) and B3 (kyphosis angle ≥ 20°,n =18).Length of hospital stay,operation time,blood loss,visual analogue scale (VAS) and Oswestry disability index (ODI) were compared between groups.Segmental kyphosis angle and vertebral wedge angle were compared between subgroups before operation,after operation and at the final follow-up.Results All patients were followed-up for 12-37 months (mean,21.2 months).There were no significant differences between the two groups in aspects of length of hospital stay,blood loss,VAS and ODI (P ＞ 0.05).Operation time was (60.62 ± 9.59) min in Group A,significantly less than that in Group B [(74.78 ± 17.66) min] (P ＜ 0.05).No breakage or malfunction of fixation occurred.There were no significant differences between the two groups in preoperative segmental kyphosis angle (P ＞ 0.05),while the correction of segmental kyphosis angle in Group B was better than Group A at the final follow-up [(7.97 ± 5.09) ° vs.(3.76 ± 1.67) °] (P ＜ 0.05).At the final follow-up,the correction of segmental kyphosis angle was similar between Group A1 and Group B1 (P ＞ 0.05),but the correction in Group B2 was better than GroupA2 (P ＜0.05) and the correction in Group B3 better than Group A3 (P ＜ 0.05).Besides,the correction of vertebral wedge angle was similar between Group A1 and Group B1 (P ＞ 0.05),but the correction in Group B2 was better than Group A2(P ＜0.05) and the correction in Group B3 was better than Group A3 (P ＜ 0.05).Loss of segmental kyphosis angle and vertebral wedge angle in Group A were greater than these in Group B (P ＜ 0.05).Conclusions Combined use of lordorizing screw with percutaneous transvertebral fixation improves the correction of thoracolumbar kyphosis angle in single-level thoracolumbar burst fractures.When the preoperative segmental kyphosis over 20°,lordorizing screw fixation should be recommended so as to achieve better correction of kyphotic deformity.

Objective To determine the outcome of unstable atlas fractures combined with rupture of transverse ligament treated by posterior atlantoaxial transpedicular screw fixation.Methods A retrospective case series study was made on 17 patients with unstable atlas fractures combined with rupture of transverse ligament treated by posterior atlantoaxial transpedicular screw fixation and fusion from January 2008 to December 2015.There were 13 males and 4 females,with age range of 34-69 years (mean,47.8 years).All atlas fractures were Jefferson fractures (Levine-Edwards type Ⅲ).Classification of transverse ligament rupture was type Ⅰ in 12 patients and type Ⅱ in 5 patients.No patients had neurologic deficit [American spinal injury association (ASIA) classification grade E].Operation time,blood loss,implant failure,bone fusion and visual analogue scale (VAS) were recorded after operation.Results Operation time was 85-120 min (mean,102 min).Blood loss was 90-150 ml (mean,115 ml).All patients were followed up for 10-20 months (mean,17.8 months).At the final follow-up,all patients achieved bone union,with no implant loosening or breakage happened.VAS was improved from preoperative (5.5 ± 1.8) points to (2.4 ± 1.5) points at tbe final follow-up (P ＜ 0.05).ASIA Grade E remained in all patients.Conclusion Posterior atlantoaxial transpedicular screw fixation of unstable atlas fractures combined with rupture of transverse ligament is a safe and effective surgical procedure that is able to restore the atlanto-axial vertebral stability and relieve pain.

Objective To evaluate the clinical efficacy of anterior C2-3 discectomy and fusion in treatment of type Ⅱ traumatic spondylolisthesis of the axis. Methods A total of 27 patients with type Ⅱ traumatic spondylolisthesis of the axis were treated with anterior C2-3 discectomy, fusion and plate fixa-tion. There were 19 males and 8 females, at average age of 38 years (22-67 years). The spinal cord function was at Fraukel D in four patients. Results Operation lasted for 75-95 minutes (mean 86 mi-nutes), with blood loss of 100-160 ml (mean 135 ml). Hospital stay was 9-12 days ( mean 10.8 days). Follow-up for 9-24 months (mean 14 months) showed that all patients achieved bony fusion within three months postoperatively, with no anterior displacement or kyphosis. The range of cervical movement was normal, with no chronic neck pain ocurred. Conclusions Anterior approach can minimize surgical trauma, shorten recovery time and hospital stay. Anterior C2-3 discectomy and fusion is a feasible and safe surgical technique and can get satisfactory therapeutic effect in treating type Ⅱ traumatic spondylolisthesis of the axis.