Objective To study a case series of thoracolumbar flexion-distraction fractures combined with compression of anterior and central columns to analyze the causes of its occult symptoms and explore the injury mechanism,imaging diagnosis and operative reduction of the fractures.Methods A retrospective study was carried out on data of 39 patients with thoracolumbar flexion-distraction fractures admitted into our hospital from May 2003 to December 2006.Of all,there were 17 patients with compression of anterior and central columns.The diagnostic value of imaging examinations such as X-ray,CT and MRI was evaluated.All patients were treated with posterior operation,in which simple distraction of the anterior and central columns was followed by compression and reduction of the posterior column from the rear axial direction.The clinical efficacy and safety of operation were assessed.Results The patients with compression of anterior and central columns accounted for 43.6% of all thoracolumbar flexion-distraction fractures.Before operation,six patients were misdiagnosed as simple compression fracture.Various kinds of imaging examinations detected the bone injury and/or ligaments complex injury of the posterior column at different degrees.The positive results on X-ray,CT,spiral CT multi-planar reconstruction (MPR)and MRI were in 8,7,11 and 17 patients respectively.After simple posterior distraction in 17 patients,there occurred over distraction in eight patients who were cured with posterior recompression plus reduction.Conclusions The posterior column injury of thoracolumbar flexion-distraction fractures combined with compression of anterior and central columns is relatively occult and easy to be misdiagnosed as simple compression fracture,when MPR CT and MRI are helpful for diagnosis.The operation with twostep reduction of axial distraction followed by compression can attain satisfactory and safe results.

Objective To assess the clinical efficacy of minimally invasive internal fixation combined with percutaneous kyphoplasty (PKP) in treatment of thoracolumbar burst fractures in the elderly.Methods Twenty-one cases of neurologically intact thoracolumbar burst fractures treated by PKP between January 2007 and December 2008 were included in this study.There were 8 males and 13 females at age of 65-78 years (means,70.6 years).Mean period from injury to operation was (3.7 ± 1.1) days (range,3-7 days).The injured segments included Ti1 in two cases,T12 in six,L1 in eight and L2 in five.Kphosis Cobb' s angle,correction degree of kyphosis angle,correction loss of kyphosis,perioperative indicators,visual analogue scale (VAS) and Oswestry disability index (ODI) were evaluated after operation.Results All the cases were followed up for a period of 26-56 months (mean 34.2 months).Operation averaged 98.7 minutes (range,80-120 minutes) and showed mean blood loss of 32.8 ml (range,30-85 ml).Ambulation started at mean 18.2 hours after operation (range,8-19 hours).VAS averaged (0.9 ± 0.6) points at postoperative one week.Postoperative X-ray films revealed mean 10.4° correction of kyphotic Cobb angle,followed by mean 1.8 °of loss in the follow-up longer than 24 months.According to hyperextension and hyperflexion radiographies,there was no abnormal activity of fixed segments,implant loosening and breakage or adjacent vertebral fractures.Conclusion Minimally invasive internal fixation combined with PKP can relieve pain and restore function in a short time and is thought to be a preferable treatment option for thoracolumbar burst fractures in the elderly.

Objective To evaluate the clinical effect of interspinous H-shaped bone grafting and bilateral facet interbody fusion in treatment of thoracolumbar fracture with severe disc injury and posterior ligamentous complex (PLC) injury after posterior pedicle screw fixation and its role in prevention of delayed kyphosis.Methods The study involved 19 cases of thoracolumbar fractures with severe disc injury and PLC injury,including 11 males and 8 females,at age of 23-59 years (mean 43.8 years.All cases were treated with posterior pedicle screw fixation (including 11 cases treated with unilateral laminectomy decompression) and C-arm X-ray showed favorable fracture reduction.For prevention of postoperative delayed kyphosis,the interspinous H-shaped bone grafting plus bilateral facet interbody fusion by using the iliac autografts was done.Neurologic recovery was assayed by using Frankel scale and lumbar and iliac pain by visual analogue scale (VAS).Cobb angle was detected as well.Results All cases were followed up for 24-64 months.At final follow-up,all cases showed neurological improvement for at least 1 to 2 Frankel grades except for two cases with Frankel Grade A,with mean Cobb angle of (2.0 ± 3.7) ° (range,-4.9°-8.1 °),mean VAS of lower back pain of (1.1 ± 1.2) points (range,0-4 points) and insignificant angle loss or kyphosis.The thin layer CT scan indicated complete integration of the transplanted bone grafts,with no complications like implant loosening or breakage.Conclusion Interspinous H-shaped bone grafting and bilateral facet interbody fusion is a good choice for prevention of delayed kyphosis after posterior pedicle screw fixation of thoracolumbar fracture with severe disc injury and PLC injury.

Objective To compare the Roussouly classification of old thoracolumbar fractures combined with post-traumatic kyphosis with that of normal adults, evaluate the effect of different kyphosis angles on sagittal curvature of the thoracolumbar spine so as to provide a theoretical basis for the clinical status and clinical treatment plan of old thoracolumbar fractures combined with post-traumatic kyphosis.Methods A retrospective case control study was made on 49 cases of old thoracolumbar fractures with post-traumatic kyphosis treated from January 2014 to December 2015 (fracture group).Damaged segments of the spine were T11 in four cases, T12 in 14, L1 in 25 and L2 in six.Another 52 normal adult volunteers were chosen as controls.Whole spine X-ray film of the two groups was taken, and the difference in Roussouly classification of the sagittal spine curvature was compared between the two groups.Patients in fracture group were separated into subgroups depending on the Cobb angle (0°-10°, 10°-20°, 20°-30°, 30°-40°, respectively), and the difference in Roussouly classification was compared among subgroups.Results Roussouly classification in control group was five cases of type 1, 12 tpye 2, 25 type 3 and 10 type 4.Results in fracture group was 14 cases of type 1, 11 type 2, eight type 3 and 16 type 4.There were significant differences in Roussouly types between the two groups (P<0.05).According to Roussouly classification, there were two cases of types 1 and 2 and seven cases of types 3 and 4 in subgroup of Cobb angle between 0°-10°;four cases of types 1 and 2 and 10 cases of types 3 and 4 in subgroup of Cobb angle between 10°-20°;12 cases of types 1 and 2 and four cases of types 3 and 4 in subgroup of Cobb angle between 20°-30°;seven cases of types 1 and 2 and three cases of types 3 and 4 in subgroup of Cobb angle between 30°-40°.There were significant differences in Roussouly types among subgroups (P<0.05).Further, Roussouly types 1 and 2 were significantly increased when the Cobb angle was >20° (P<0.05).Conclusions Post-traumatic kyphosis in old thoracolumbar fractures affects spine sagittal curvature.Patients with sagittal spinal imbalance (Roussouly types 1 and 2) are more with increased Cobb angle.Moreover, Cobb angle >20°may be the reference basis for clinical intervention.

Objective To investigate characteristics of cage migration after transforaminal lumbar interbody fusion (TLIF) and related risk factors.Methods A retrospective study was conducted to review cage migration in 512 patients who had undergone TLIF procedure from January 2010 to June 2011 in 5 spinal research centers.There were 255 males and 257 females,aged from 37 to 77 years (average,54.7 years).All patients were followed up at 3,6,12 months after operation.The clinical outcomes were evaluated using the visual analogue scores (VAS) and Oswestry disability index (ODI).X-rays and 3D CT scans were used to analyze the incidence and related risks factors of cage migration in these patients.Results Cage migration was found in 6 of 512 patients,the total incidence was 1.17％.Significant difference was found between each center.Cages with different shapes had different incidence.The analysis showed that the incidence of migration of rectangular-shaped cage (3.11％,5/161) was significantly higher than that of kidney-shaped cage (0.28％,1/351).The cage in double-segment TLIF (5.75％,5/87) was easier to migrate than that in monosegment TLIF (0.24％,1/425); furthermore,linear type endplate(3.50％,5/143) was remarkably easier to migrate than concave-concave one (0.27％,1/369).Conclusion Difference in operative skills,cage shape,number of fused segments,adjacent endplate shape,and lumbar spondylolisthesis might be risk factors for cage migration after TLIF.

The oblique lumbar interbody fusion (OLIF) procedure has yielded favorable outcomes for individuals afflicted with degenerative lumbar conditions; however, certain complications warrant attention. We present a case of a 48-year-old female experiencing recurrent radicular pain post-OLIF. This patient, who endured persistent lower back discomfort for a decade, underwent MRI scans which revealed an intervertebral disc herniation at the L 4, 5 level and L 4 spondylolisthesis. The length of the right upper articular process of L 5 was 10.46 mm, and the distance between right upper articular process of L 5 and right nerve root of L 4 was 1.34 mm. Subsequent to OLIF, she reported recurrent radicular pain in her right leg. Post-operative CT scans revealed that the inclination of the right upper articular process of L 5 augmented from 59.46° to 65.22°. The distance from this process to the anterior foramen wall diminished from 0.63 mm to 0.25 mm, while its distance from the superior wall expanded from 0.31 mm to 0.39 mm. Furthermore, the foraminal cross-sectional area decreased from 0.29 mm 2 to 0.18 mm 2, and the lordotic angle of the intervertebral space amplified from 0.52° to 7.33°. Such measurements suggest that following OLIF, there was asymmetric retraction of the intervertebral space, accompanied by an anteroinferior tilt of the upper articular process, leading to persistent nerve root compression and thus necessitating immediate surgical nerve root decompression. This paper also elucidates the influence of the anatomical characteristics of the facet joint or articular process on lumbar functionality. Consequently, it could be postulated that hypertrophic or aberrantly elongated articular processes might induce nerve root compression due to intervertebral space retraction post-OLIF. Hence, spine surgeons should diligently assess and recognize the ramifications of such anomalies on OLIF surgical outcomes.

Objective:To investigate the short-term clinical outcomes of posterior percutaneous pedicle screw fixation combined with percutaneous vertebroplasty (PVP) for treating Kümmell's disease with intravertebral instability.Methods:A retrospective case series study was made on 18 patients with Kümmell's disease with intravertebral instability treated at Lishui Hospital of Zhejiang University from January 2012 to February 2016. There were 4 males and 14 females, aged 65-86 years [(76.0±5.5)years]. Segment of injury was T 7 in 1 patient, T 10 in 2, T 11 in 3, T 12 in 4, L 1 in 6, and L 2 in 2. All patients underwent posterior percutaneous pedicle screw fixation combined with PVP. The operation time, intraoperative blood loss, amount of cement injected into the vertebra, and length of postoperative hospital stay were recorded. The visual analogue scale (VAS), Oswestry disability index (ODI), Cobb angle, and wedge angle of the operative segment were recorded and compared preoperatively, postoperatively, and at the latest follow-up. Meanwhile, the complications were recorded. Results:All patients were followed up for 12-28 months [(17.7±4.4)months]. The operation time was 110-175 minutes [(137.9±21.9)minutes] and the blood loss was 50-165 ml [(110.7±35.6)ml]. The amount of cement injected into the vertebra was 2.5-6.0 ml [(4.7±0.9)ml]. The length of hospital stay was 7-14 days [(9.4±2.3)days]. The VAS was (7.8±1.2) points preoperatively, (3.3±0.7) points at 1 week postoperatively and (2.4±0.7)points at the latest follow-up. The ODI was (67.3±7.3)% preoperatively, (30.5±7.5)% at 1 week postoperatively and (21.8±8.3)% at the latest follow-up. The Cobb angle was (26.2±9.5)° preoperatively, (12.6±7.2)° at 1 week postoperatively and (16.7±6.2)°at the latest follow-up. The wedge angle was (21.1±6.1)° preoperatively, (8.4±4.6)° at 1 week postoperatively, and (13.2±4.1)° at the latest follow-up. The above clinical and radiological parameters were significantly improved after operation ( P<0.05), and showed no significant differences at the latest follow-up when compared to that at 1 week postoperatively ( P>0.05). Five patients showed slight screw loosening, but there was no obvious dislocation of internal fixation. One case developed distal vertebral compression fracture at 6 months postoperatively and cured after a second PVP. Conclusion:For Kümmell's disease with intravertebral instability, posterior percutaneous pedicle screw fixation combined with PVP can effectively restore and maintain the spinal sequence, rapidly relieve the pain and improve clinical function. However, the long-term efficacy needs further study.

Objective:To investigate the preliminary clinical and radiographic outcomes of percutaneous endoscopic lumbar discectomy (PELD) combined with oblique lateral interbody fusion (OLIF) for the degenerative lumbar spondylolisthesis, lumbar spine instability or lumbar spinal stenosis with ruptured disc herniation.Methods:Data of 11 patients with degenerative lumbar spondylolisthesis, lumbar spine instability or lumbar spinal stenosis with ruptured disc herniation who had undergone PELD combined with OLIF between March 2017 to July 2018 in our spine surgery center were retrospectively analyzed. There were 5 males and 6 females with an average age of 61.2±6.8 years old. All the patients were diagnosed with degenerative lumbar diseases including lumbar spondylolisthesis (7 cases), lumbar spinal stenosis (3 cases) and segmental instability (1 case). The patients were treated with PELD combined with OLIF. The visual analogue scale (VAS) scores of low back pain and lower limb pain and the Oswestry disability index (ODI) of lumbar function, spinal canal anteroposterior diameter, intervertebral disc height, vertical diameter of intervertebral foramen, segmental angle and the whole lumbar lordotic angle were collected.Results:All patients received PELD with local anesthesia before OLIF with general anesthesia. The mean operation time was 52.3±13.2 min and the mean blood loss was 10.9±4.7 ml for PELD. The mean operation time was 56.8±18.0 min and the mean blood loss was 65.5±24.6 ml for OLIF. All patients were followed up for an average of 11.2 months. At the latest follow-up, the mean VAS score for back pain was 1.3±0.8, the mean VAS score for leg pain 1.1±0.5, the mean ODI 14.6%±5.3%, thus all of those were improved significantly compared to those of pre-operation ( t=10.37, 16.49, 8.73; P< 0.05). The radiographic results showed the mean pre-operative intervertebral disc height, vertical diameter of intervertebral foramen, spinal canal anteroposterior diameter, segmental angle, and lumbar lordosis angle was 7.1±1.2 mm, 15.3±2.2 mm, 6.2±1.3 mm, 10.2°±3.5°, 16.2°±6.2°, and thus all of those were increased significantly to the latest follow-up 11.5±1.8 mm, 19.2±2.6 mm, 10.4±2.5 mm, 19.3°±7.8°, 27.4°±8.3°, respectively ( t=5.83, 4.21, 6.59, 10.32, 7.65; P< 0.05). One of the patients had weakness of flexor hip strength and one had a transient paresthesia immediately post-operation. All symptoms were relieved within 1 month. Another one case had cage subsidence and encountered serious back pain after 1 month, and alleviated after percutaneous pedicle screw fixation. Conclusion:PELD combined with OLIF can overcome the limitations of OLIF with indirect decompression effects, resulting in successful direct neural decompression without posterior decompressive procedures and providing a satisfactory outcome for the patients with degenerative lumbar diseases with ruptured disc herniation.

Objective:To investigate the characteristics and causes of endplate injury in the oblique lateral interbody fusion for the treatment of lumbar diseases, and summarize the precaution of endplate injury.Methods:Thirty-five cases of endplate injury were observed, which were originally treated with oblique lateral interbody fusion with or without pedicle screw fixation from October 2014 to December 2017. There were 7 males and 28 females, and the age ranged from 51 to 78 years old (averagely 62.8±8.13 years). There were 2 cases of lumbar disc degeneration, 10 cases of lumbar canal stenosis, 17 cases of lumbar degenerative spondylolisthesis, 2 cases of lumbar spondylolysis with or without spondylolisthesis, and 4 cases of lumbar degenerative scoliosis. Lesion sites contained L 3,4 in 2 cases, L 4,5 in 21 cases, L 2-4 in 3 cases, L 3-5 in 4 cases, L 2-5 in 3 cases and L 1-5 in 2 cases. Preoperative bone mineral density examination revealed there were 7 cases of T>-1 SD, 24 cases of -2.5 SD