Objective To investigate a reliable and practicable model of intraoperative neurophysiological monitoring (IONM) in oblique lateral interbody fusion (OLIF) combined with posterior transpedicle internal fixation.Methods A total of 34 consecutive patients who underwent OLIF combined with posterior transpedicle internal fixation with IONM at the SRRSH from November 2014 to July 2016 were collected and follow-up at least for 3 months postoperative.The intraoperative somatosensory evoked potentials (SEP),motor evoked potentials (MEP),dermatomal somatosensory evoked potential (DSEP) and spontaneous electromyography (sEMG) were used and evaluated,besides,triggered electromyography (tEMG) was used to monitor the implantation of pedicle screws,the possible reasons and treating procedures of monitoring alerts were summarized.Results A total of 34 cases of patients were effectively monitored during OLIF combined with posterior transpedicle internal fixation.SEP monitoring was successful in all patients,and no abnormal SEPs were observed in all cases.DSEP monitoring was successful in 20 cases (58.8％),and no abnormal DSEPs were observed in these patients.MEP was successfully monitored in all cases,eliminating the anesthesia factor,no abnormal MEPs were observed in all cases.The sensitivity and positive predictive value of SEP,MEP,DSEP were 0％.3 cases had abnormal sEMG reactions during the channel establishment which disappeared after adjustment of channel,and 2 cases which appeared abnormal wave recovered after brief observation.Among the 5 patients with abnormal wave,one case got numbness,one patient felt pain in front of the thigh postoperative.Among the other 29 patients without abnormal wave during channel establishment,one case appeared numbness.These 3 patients with neurologic symptoms recovered in 3 months after conservative treatment.The sensitivity and specificity of sEMG was 66.7％ and 90.3％ respectively,negative predictive value and positive predictive value were 96.6％ and 40％ respectively.6 screws got tEMG response after tapping even the intensity was less than 10mA,which showed broken codex of pedicle according to postoperative CT scan.Cornclusion Intraoperative application of sEMG monitoring in OLIF can obviously reduce the incidence of the neurological deficit,which was an effective method,tEMG monitoring during lumbar pedicle screw fixation can detect the mal-positioned screws and protect the nerve roots.SEP,MEP and DSEP did not seem well suited for OLIF.

Objective To explore the possible pathological essence of HIZ in lumbar intervertebral disc by means of CT,MRI and histomorphology analysis.Methods All of 41 patients of low back pain with the HIZ in the lumbar disc on MRI were identified.There is 23 males and 18 females with mean age of 38 years (range 33-50 years).All the patients were divided into 2 groups according to the characteristics of HIZ on MRI:group A,29 patients with high intensity on MRI T2WI and low intensity on MRI T1WI; group B,12 patients with high intensity both on T2WI and T1WI.All these patients underwent X-rays and CT scan on the targeted level.26 patients in group A were performed discography and pain provocative test.15 patients in group A and 7 patients in group B underwent operation and those samples of HIZ region were excised for HE staining and immunohistochemical analysis.Results All the patients in group A were proved intervertebral disc degeneration on CT and MRI.21 patients in 26 who underwent discography and pain provocative test were proved positive and 15 of them underwent operation(Transforaminal lumbar interbody fusion or posterior lumbar interbody fusion).Histomorphology examination showed annular tear combined with granulation tissue in the samples of HIZ region which were excised in operation.Neoformative blood capillary could be seen through CD34 staining.Macrophage could be found in CD68 staining,but the regions off the HIZ were less stained.In group B,all those targeted discs showed calcified or ossified lesion on the posterior annular on CT scan,HE staining showed calcification or ossification of the posterior annulus fibrosus with frontier line.Conclusion The HIZ on MRI T2WI with low intensity zone on T1WI possibly refers to annular tear combined with granulation in-growth.But the HIZ both on MRI T2WI and T1WI might be calcification or ossification.The conventional concept of HIZ might be modified as HIZ on MRI T2WI,but low intensity zone on MRI T1WI.In addition,CT scan might be helpful in the distinguished diagnosis.

Objective To study the anatomic features of surface vasa vasorum on longissimus in thoracolumbar segments,and its protection function during the internal fixation for thoracolumbar fracture via Wiltse approach.Methods From March 2010 to October 2012,a total of 97 patients with thoracolumbar fractures underwent posterior internal fixation with pedicle screw system.The trend and distribution of surface vasa vasorum on longissimus in thoracolumbar segments were observed in the operation,and the vessels were protected during the surgical procedures by using specific devices and techniques.Operative time and intra-operative blood loss were recorded.Visual analogue scale (VAS) values were evaluated after 3 days,1 month,6 months postoperatively,and 1 month after the removal of internal fixation.MRI images of longissimus in thoracolumbar segments were compared after preoperative and postoperative 6 months.Results Surface vasa vasorum distribution on 194 longissimus and 402 inter-pedicle areas of 97 patients were observed.In 402 areas,94.3％ of surface vasa vasorum presented sarciniform,while only 5.7％ of surface vasa vasorum presented tube shape.In 379 areas of sarciniform distribution,9.8％ of blood vessel bundles were located in vertebral pedicle area;76.0％ of blood vessel bundles were located in the upper inter-pedicle areas;12.4％ of blood vessel bundles were located in middle inter-pedicle areas;1.8％ of blood vessel bundles were located in lower inter-pedicle areas.In 379 areas,87.3％ of blood vessel bundles could be completely retained;12.7％ of blood vessel bundles were treated by electro coagulation and burning.Intra-operative blood loss was 21±9.3 ml.VAS values after 3 days,1 month,6 months postoperatively,and 1 month after the removal of internal fixation were 3.3± 1.6,2.1± 1.4,1.2±0.7 and 1.1±0.7.The longissimus treated with electro coagulation demonstrated pimelosis change on MRI after postoperative 6 months.Conclusion Surface vasa vasorum on longissimus in thoracolumbar segments are generally of sarciniform,and most of them are located in upper inter-pedicle areas.The protection of vasa vasorum can reduce the intra-operative lesion and postoperative pimelosis change of longissimus.

Objective To study the effect of precise locating technique of C?arm fluoroscopy in order to reduce the radia?tion exposure during the surgical procdure for thoracolumbar fracture. Methods From March 2010 to Octorber 2012, a total of 92 cases with thoracolumbar fracture underwent postierior internal fixation procdures with pedicle instrumentation. C?arm fluoros?copy was used in 44 cases with precise locating technique, while in 48 cases with traditional methods. In precise locating group,C?arm fluoroscopy was used after anesthesia. Once an ideal view was got, the position parameters of C?arm fluoroscopy machine were recorded. The machine was positioned according to the recording for the secondary fluoroscopy. Pre?operative and intra?operative number of times of exposure, length of exposure time, time for fluoroscopy and total operating time were recorded and compared be?tween two groups. Results Pre?operative number of times of exposure, exposure time, and time for fluoroscopy in precise locating group were (5.51±2.47), (2.26±1.05) s and (9.83±3.67) min,which were higher than those of (4.02±2.42), (1.78±0.98) s and (8.29± 3.52) min in traditional group. However, intra?operative number of times of exposure, exposure time, and time for fluoroscopy in precise locating group were (5.26±3.64), (2.24±1.24) s and (10.39±4.82) min,which were lower than those of (9.74±4.38), (4.21± 2.38) s and (24.69±6.35) min in traditional group,and total number of times of exposure, exposure time, time for fluoroscopy and total operating time in precise locating group were(10.77±4.16), (4.50±1.83) s, (20.22±5.03) min and(70.52±18.33)min,which were also lower than those of (13.76±5.31), (5.99±3.27) s , (32.98±7.83) min and(81.86±21.57)min in traditional group. Conclu?sion Precise locating technique of C?arm fluoroscopy reduces the radiation exposure during the surgical procdure for thoracolum?bar fracture.

Objective To compare the clinical and radiographic outcomes of 3 kinds of lumbar interbody fusion (ALIF,PLIF,TLIF) for adult low-grade isthmic spondylolisthesis at L4.5 and L5S1 levels.Methods Data of seventy patients with lowgrade isthmic spondylolisthesis who had undergone different lumbar interbody fusion (LIF) procedures according to the assessment of the clinical manifestation,neurological symptoms,plane of the common iliac vessels and the width of vascular window by three-dimensional computed tomography angiography between May 2004 and May 2014 were retrospectively reviewed.21 patients had undergone anterior LIF (ALIF)(13 males and 8 females with an average of 43.29±8.15 years old (range,29-53 years old);L4,5 in ten,L5S1 in 11;Meyerding grade Ⅰ 10 cases,grade Ⅱ 11 cases);25 patients had undergone posterior LIF (PLIF) (12 males and 13 females,with an average of 44.04±12.71 years old (range,25-64 years old);L4.5 in 12,L5S1 in 13;Meyerding grade Ⅰ 15 cases,grade Ⅱ 10 cases) and 24 patients had undergone transforaminal LIF (TLIF) (12 males and 12 females with an average of 45.00± 9.36 years old (range,34-62 years old);L4,5 in 12,L5S1 in 12;Meyerding grade Ⅰ 11 cases,grade Ⅱ 13 cases).Results All patients were followed up for 24-37 months (average,25.6±8.7 months).The visual analogue scale (VAS) in all groups were decreased from 7.05±0.87 (ALIF),6.60±1.39 (PLIF),6.75±1.11 (TLIF) pre-operation to 0.90±0.70,0.96±0.68,1.04±0.62 24 months after operation.Oswestry disability index (ODI) scores were decreased from 78.53％±6.25％,79.80％±6.55％,79.92％±8.10％ preoperation to 17.14％±3.01％,21.32％±4.40％,22.46％±3.87％.Perioperative data including operation time,blood loss,postoperative blood drainage,length of stay showed no significant difference between ALIF group and TLIF group,but showing significant difference comparing with PLIF group.The imageological results showed that ALIF procedure increased whole lumbar lordosis (WL) and disc height (DH),showing no significant difference comparing with PLIF group,but showing significant difference comparing with TLIF group.The ALIF procedure increased segmental lordosis angle (SL),showing significant difference comparing with PLIF group and TLIF group.The PLIF procedure decreased spondylolisthesis index (SI),showing significant difference comparing with A/TLIF group,but showing no significant difference between ALIF group and TLIF group.There was no significant difference showed comparing the L1 axis S1 distance (LASD) and sacral slope (SS),in three groups.The graft fusion was achieved in all patients after 6-8 months postoperatively without instrument failure or displacement.Conclusion Three surgical procedures of lumbar interbody fusion for adult low-grade isthmic spondylolisthesis showed silimar clinical efficacy.The ALIF procedure is superior in its capacity to restore WL,DH,and SL,and the P/TLIF procedure are superior in correcting the vertebral slippage and spinal cord decompression.

Objective To assess incidence rate of different types of cement leakage in percutaneous kyphoplasty (PKP) with or without intravertebral clefts and to determine whether basivertebral foramen could be connected with intravertebral cleft.Methods 270 vertebrae in 224 consecutive patients who underwent percutaneous kyphoplasty for treatment of osteoporotic vertebral compression fractures were classified into two groups on preoperative radiographs,computed tomography scans,and/or magnetic resonance images of the treated levels:Cleft group with an intravertebral cleft in vertebral body and trabecular group without intravertebral clefts.On direct postoperative images,the patterns of cement leakage were classified as 5 types:through a cortical defect into paraspinal soft tissues (type A),through the basivertebral foramen (type B),via the needle channel (type C),through a cortical defect into the disc space (type D),via the paravertebral vein (type E).The incidence of different types of cement leakage between two groups was analyzed.Results In 72 of 270 vertebrae,an intravertebral cleft was confirmed on preoperative images.Leaks through basivertebral foramen as type B (42,15.5％) and through cortical defects into the disc space as type D leaks (21,7.8％) were more common than other types.The incidence of type B leakage in the cleft group (23.6％) was higher than the incidence in the trabecular group (12.6％),which made a statistical significance (P=0.028).There was no statistical difference between the trabecular pattern and the cleft pattern on other types of leaks.Conclusion Type B leaks were more common in vertebrae with the presence of an intravertebral cleft,which support the presence of the connection between an intravertebral cleft and the basivertebral foramen.Thus,care must be taken when PKP was performed in these patients to avoid cement leakage into spinal canal through basivertebral foramen directly.

Objective To evaluate the early clinical outcomes and complications of oblique lateral interbody fusion (OLIF) in the treatment of degenerative lumbar diseases.Methods All of 83 patients,29 males and 54 females with ages from 32 to 83 (average 60.8± 13.7 y),underwent OLIF with or without posterior pedicle screw-rod instrumentations from October 2014 to February 2017.The index diagnosis was discogenic back pain in 17 cases,spondylolisthesis in 23,lumbar spinal canal stenosis in 25,and degenerative lumbar spinal kyphoscoliosis in 18 cases.The distribution of operative level was 5 at L1,2,13 at L2,3,38 at L3,4,and 69 at L4,5.The mean number of fusion level for each case was 1.5 segments.The operative duration,blood loss during operation,intra-operative and post-operative complications,the length of post-operative hospital stay were recorded.Clinical outcomes were evaluated using visual analogue scale (VAS) and Oswestry disability index (ODI).All patients were followed up for at least 3 months.Lumbar X-ray and CT scans were taken and the clinical outcomes were re-assessed during follow-up.Results Fifty-one in the 83 patients underwent supplementary posterior pedicle screw-rod instrumentation with OLIF procedures.The operation lasted for 43-295 min,with a mean duration of (153 ± 72) min.Mean operation time for each OLIF segment was 43± 12 min.Blood loss during the operation was 30-800 ml,with a mean of 125±74 ml.Mean blood loss for each OLIF segment was 27±13 min.Average length of stay was 5.6 ± 3.2 d,ranging from 3-15 d.The VAS for back pain and leg pain and ODI scores were decreased apparently for each patient.The total incidence of complications was 22.9％ (19/83),including 6.0％ (5/83) of intra-operative complications (4 cases of cage subsidence,1 case of segmental artery injury) and 16.9％ (14/83) of post-operative ones.The latter consisted of ipsilateral hip flexor weakness in 6,ipsilateral anterolateral thigh pain in 2,ipsilateral lateral thigh numbness in 1,contralateral pain in flexion of hip in 1,ipsilateral sympathetic chain injury in 2,and pain in area of iliac bone donor site in 2.All symptoms were released or disappeared during follow-up.Conclusion OLIF as a novel minimally invasive technique can act as a safe and effective treatment for degenerative lumbar diseases,which can also reduce approach-related complications.

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.

Objective To evaluate the clinical outcomes of oblique lateral interbody fusion (OLIF) in the treatment of adult degenerative scoliosis (ADS).Methods From January 2015 to May 2016,17 ADS patients,4 males and 13 females were enrolled with ages from 46 to 80 (average 69.5±9.2 years).The Cobb angle of all was greater than 10°.According to Lenke-Silva classification systems:Ⅰ level,2 cases,decompression alone;Ⅱ level,2 cases,decompression and limited instrumented spinal fusion;Ⅲ levels,4 cases,decompression and lumbar curve instrumented fusion;Ⅳ levels,5 cases,decompression with anterior and posterior spinal instrumented fusion;Ⅴ level,4 cases,thoracic instrumentation and fusion extension.The operation time,blood loss,blood transfusion,and preoperative and postoperative complications were recorded.Clinical and radiological outcomes were evaluated using visual analogue scale (VAS),Oswestry disability questionnaire (ODI) scores,sagittal vertical axis (SVA) and coronal Cobb.All cases were followed up in 3,6,12 and 24 months.Results All of 17 cases underwent OLIF,one level 4 cases,two levels 2 cases,three levels 7 cases and four levels 4 cases.Alone OLIF was 5 cases (2 case of Ⅰ level,1 case of Ⅱ level,1 case of Ⅲ level and 1 case of Ⅳ level).OLIF combined with posterior approach was 12 cases and the interval time were 1-2 weeks,the mean were 1.7±0.5 weeks.Among these 12 cases,posterior fixation was 6 cases,posterior fixation and decompression was 2 cases,and L5/S1 interbody fusion was 4 cases.The operation lasted for 50-460 min,with a mean duration of 230.6± 132.0 min.Blood loss during the operation was 30-640 ml,with a mean of 306.5±213.8 ml.No patient had blood transfusion.The follow-up was 12-28 months and the mean was 17.9±4.5 months.The preoperative Cobb angles were 16.2°-37.7°,the mean was 29.1°±6.4°.The postoperative Cobb angle were 1.5°-10.2°,and the mean were 5.6°±2.4°.The Cobb of all cases improved significantly.The SVA was returned to the normal level in 4 cases of Lenke-Silva V level.The VAS and ODI score decreased from 7.1 ±0.7 preoperatively to 2.4±0.9 at last follow-up,and from 37.9±2.5 to 10.9±3.0,respectively,and both of them were improved significantly.2 cases of OLIF had cage malposition.Left hip flexor weakness occurred in 5 cases and recovered completely within 2 weeks.Left anterior thigh pain occurred in 1 case and disappeared within 2 weeks.Left sympathetic chain injury happened in 1 case and recovered at last follow-up.Conclusion OLIF as a management of ADS showed excellent short-term outcomes.Clinical and radiological results,such as VAS,ODI and Cobb angle,were improved in all cases.OLIF will be a good choice for the treatment of ADS.

Objective To investigate the indirect decompression effect of oblique lateral interbody fusion (OLIF) in the treatment of mild to moderate degenerative lumbar stenosis.Methods From October 2014 to November 2016,23 patients with mild to moderate lumbar spinal stenosis underwent OLIF combined with or without posterior pedicle screw fixation;9 males and 14 females with average age of 59.2±11.6 years old;8 cases at L3,4 segment and 15 cases at L4,5 segment.All cases were followed up for more than 6 months.Thin layer scanning of CT and two-dimensional reconstruction images were used to measure the vertical diameter and area of intervertebral foramen.Intervertebral disc height and spinal canal anteroposterior diameter were measured on median sagittal MRI sequence,and the anteroposterior diameter and the cross-sectional area of the spinal canal were measured on cross-sectional MRI sequence.The clinical effects were assessed by the visual analogue score (VAS) and the Oswestry disability index (ODI) for low back pain,lower limb pain and lower limb numbness.Results Compared with those measurements pre-operatively,the post-operative intervertebral disc height increased by 78.6％±13.4％.The post-operative left vertical diameter of intervertebral foramen increased by 36.7％±7.8％,and the post-operative left area of intervertebral foramen increased by 36.6％± 8.7％,and the post-operative right vertical diameter of intervertebral foramen increased by 40.7％±9.6％,and the post-operative right area of intervertebral foramen increased by 40.0％±8.9％.The post-operative anteroposterior diameter of sagittal spinal canal were increased 32.6％ ± 5.9％,and the post-operative anteroposterior diameter of cross-sectional spinal canal were increased 34.4％±6.8％,and the post-operative cross-sectional area of the spinal canal were increased 47.5％±7.2％.All of the differences were statistically significant between pre-operative and post-operative measurements.The VAS score for low back pain was 6.2± 1.7 pre-operatively,and 1.1±0.5 post-operatively.The ODI for low back pain was 81.2％± 18.2％ pre-operatively,and 6.1％±2.0％ post-operatively.The VAS score for lower limb pain was 5.6±1.4 pre-operatively,and 0.8±0.3 post-operatively.And the VAS score for lower limb numbness was 6.6±2.0 pre-operatively,and 3.4± 1.2 post-operatively.All of the differences were statistically significant between pre-operative and post-operative evaluations.Conclusion There were obvious radiological evidences and remarkable clinical effect of indirect decompression using OLIF technique in treatment of mild to moderate lumbar spinal stenosis at early post-operative stage.However further long-term follow-up studies with multicenter large sample were still needed.