Objective:To investigate the feasibility and clinical efficacy of posterior vertebral column resection (PVCR) combined with polymethylmethacrylate-augmented pedicle screw instrumentation and shortening of spinal column for stage Ⅲ Kümmell's disease with very severe collapse of fractured vertebra.Methods:From January 2017 to September 2021, 9 patients with stage Ⅲ Kümmell's disease with very severe collapse of fractured vertebra underwent PVCR combined with polymethylmethacrylate-augmented pedicle screw instrumentation and shortening of spinal column. Their medical records were retrospectively analyzed. There were 1 male and 8 females, aged (66.9±5.8) years. The injured vertebra was located at T 11 in 2 patients, at T 12 in 4, at L 1 in 2 and at L 2 in 1. X-ray, CT and MRI were performed before operation. The posterior intervertebral heights of adjacent vertebral bodies of the fractured vertebra in the median sagittal position were measured on CT or MRI to evaluate the shortening of the spinal column before PVCR. Recorded were intraoperative bleeding volume, operation time, complications, bone graft fusion, and American Spinal Injury Association (ASIA) grading at preoperation and the last follow-up. The visual analogue scale (VAS) pain scores, Oswestry disability index (ODI) scores, and kyphotic cobb angles at preoperation, 1 week and 3 months postoperation, and the last follow-up were compared to evaluate the clinical efficacy of PVCR. Results:All patients underwent surgery successfully, with tight closure of adjacent vertebrae after resection of the injured vertebra and bone grafting. Operation time was (240.6±23.2) min and intraoperative bleeding (505.6±95.0) mL. The 9 patients were followed up for (17.3±5.6) months. No worsening symptoms of nerve injury, cerebrospinal fluid leakage, or other serious complications were found after operation, nor such complications as loosening or breakage of internal fixation or adjacent vertebral fractures. Bone fusion was achieved at the bone graft sites in all patients by the last follow-up. The VAS and ODI scores and cobb angles at 1 week and 3 months postoperation and at the last follow-up were significantly decreased compared with preoperation ( P<0.05). There were no significant differences in VAS scores or cobb angles among postoperative 1 week and 3 months and the last follow-up ( P>0.05), but pairwise comparisons between different time points after operation showed significant differences in ODI, with postoperative 1 week > postoperative 3 months > the last follow-up ( P<0.05). The ASIA grading at the last follow-up was improved from preoperative grade C to grade D in 2 cases, from preoperative grade C to grade E in 1 case and from preoperative grade D to grade E in 5 cases. Conclusion:PVCR combined with polymethylmethacrylate-augmented pedicle screw instrumentation and shortening of spinal column is a feasible and effective surgical treatment for stage Ⅲ Kümmell's disease with very severe collapse of fractured vertebra, leading to good clinical efficacy.

Objective To identify prognostic factors ofmotorfunctionafter surgery of metastatic spinal cord compression (MSCC).Methods The clinical data of 681 patients with spinal metastases from January 2008 to December 2017 were retrospectively analyzed.According to inclusion and exclusion criteria,a total of 206 patients with spinal metastatic were included.Postoperative neurological function was assessed using Frankel classification.The influence of age,gender,preoperative status,number of spine metastases,location of spinal metastases,visceral metastases,bone metastases,primary tumor type,interval from symptom to surgery,time of developing motor deficits,interval from primary tumor diagnosis to MSCC,preoperativethe Eastern Cooperative Oncology Group performance status (ECOG-PS),Karnofsky Performance score (KPS) and surgical procedures on postoperative function outcomes were explored.Results 140 (68.0％) patients were able to walk postoperatively compared with 88 (42.7％) patients preoperatively.Moreover,in 89.8％ of all patients,79 ambulatory patients maintained ambulation after treatment.The univariate analysis according to Ordered-logit model showed thatnumber of spine metastases,location of spinal metastases,preoperative ECOG-PS,preoperative KPS,interval from symptom to surgery and time of developing motor deficits were related with posttreatment motor functions.The multivariable analysis showed that number of spine metastases (OR=2.03;95％CI:1.12-3.33;P=0.04),preoperative ECOG-PS (OR=4.84;95％CI:2.42-8.15;P=0.038),interval from symptom to surgery (OR=3.78;95％CI:3.12-9.15;P=0.024),time of developing motor deficits(OR=2.75;95％CI:1.22-3.89;P=0.01) were independent prognostic factors for function outcomes.Conclusion 1-2 levels of metastasis,Interval from symptom to treatment ≥ 48 h,time of developing motor deficits ≥7 d,and ECOG-PS 1-2 can be considered as the most significant positive prognosticfactors for post-treatment ambulatory status.Spinal metastasis should have a higher priority,and immediate intervention should be started before the development of irreversible neurologic deficits.Increasing awareness of early symptoms and earlier screeningwith regular outpatient review might make a difference for patients with MSCC.Consequently,the identified prognostic factors can be considered as apreoperative assessment tool to predict the neurologic outcomeand guide clinical treatment for individual patients with MSCC.

Objective To evaluate the prognostic factors of spinal metastases by recursive partitioning analysis (RPA)and establish a decision tree model that can guide clinicians to select individualized treatment.Methods Between January 2011 and December 2015,three institutional databases were searched to identify 169 patients with metastatic spinal tumors underwent surgery.The ratio of male and female was 1.48:1 (102 males and 67 females).The average age was 59.2±11.1 years.One-hundred eighteen cases of patients were randomly selected as training samples and the remaining 51 cases were verified samples.Preoperative factors were collected and analyzed by RPA methods,including primary tumor,KPS score,Frankel grade,gender,age,visceral metastasis,bone metastasis,spinal metastasis,blood glucose,blood pressure,surgery site,symptoms,surgery interval,serum albumin level and other risk factors.Pearson's Chi-square test was performed to judge the segmentation point of the decision tree model.The decision tree model is built using the Chi-square automatic interaction detector (CHIAD) algorithm and sensitivity and specificity was automatically calculated.Results The median postoperative survival time was 12.6±1.2 months [95％CI(10.1,15.0)].70％ were randomly selected as the experimental group (118 cases),and 30％ were the verification group (51 cases).The sensitivity was 96.9％.The specificity was 89.8％.The Kappa coefficient was 0.874 in the experimental group.The sensitivity was 95.4％.The specificity was 90.8％.The Kappa coefficient was 0.810 in the test group.The prognostic factors (weight from high to low) based on RPA were Frankel grade (F=8.132,P=0.005),the primary tumor and the KPS score (Equal,F=9.871,P=0.000 and F=1 1.945,P=0.003),serum albumin and movement time (Equal,F=7.566,P=0.018 and F=9.966,P=0.008).The decision tree model consists of 7 types.Survival time was 51 months,18 months,13 months,8 months,4 months,5 months,9 months in the class Ⅰ～Ⅶ,respectively.According to the difference of RPA survival time,the operation was classified as 3 grade.Total spinal resection was regarded as grade 1,including class Ⅰ and class Ⅱ,with an average survival time of over 18 months.Limited operation was regarded as grade 2,including class Ⅲ,Ⅴ and Ⅶ with survival time in 6-18 months.The conservative treatment was regarded as grade 3,including class Ⅳ and Ⅵ with the survival time was less than 6 months.Conclusion The decision tree model based on RPA for predicting the survival time of spinal metastases can not only identify the prognostic factors,but also classify and grade various prognostic factors;the decision tree model is simple and can guide clinicians to choose the best surgical plan by predicting the survival time.

Objective To assess the efficacy of internal fixation assisted with Halo-vest in the treatment of Anderson-D'Alonzo type Ⅱ and superficial type Ⅲ odontoid fractures.Methods A retrospective case series study was made on 15 patients clinically diagnosed as Anderson-D'Alonzo type Ⅱ and type Ⅲ odontoid fractures with a fracture gap over 2 mm,displacement over 5 mm and broken end angel over 11° from January 2007 to January 2015.There were nine males and six females,aged 27-61 years [(44.5 ± 10.9)years].The patients were treated in "three phases" with the assistance of Halo-vest external fixation system and a novel guide pin aiming device.The three phases were as follows:phase Ⅰ:cervical traction reduction and halo-vest external fixation;phase Ⅱ:Halo-vest assisted internal fixation using the novel aiming device;phase Ⅲ:the Halo-vest fixation removal and cervical collar fixation.Operation duration,intraoperative bleeding,and postoperative visual analogue scale (VAS) pain score one month after the operation were recorded.The cervical lateral and open mouth X-ray or atlantoaxial CT scan with sagittal and coronal two-dimensional reconstruction were regularly reviewed,and the location of screws,reduction and fracture healing were evaluated.Results Operation duration ranged from 54 to 96 minutes [(71.3-± 11.9) min].The intraoperative blood loss was 5-60 ml [(32.6 ± 16.8) ml].There was no spinal cord or nerve root injury,cerebrospinal fluid leakage,wound infection or other complications.All patients were followed up for 12-36 months (mean,28 months).Fourteen patients were seen bony union 6 months after the surgery and one patient was seen a false joint.At the last follow-up,the patient with false joint was seen bone sclerosis,and other patients with sound bone healing.The preoperative VAS and that of one month after the operation was (7.3 ± 0.6) points and (1.6 ± 0.7) points,respectively (P ＜ 0.05).Conclusion For Anderson-D'Alonzo type Ⅱ and type Ⅲ odontoid fractures,which have a fracture gap greater than 2 mm,displacement more than 5 mm,broken end angle above 11 degrees,the three-phase Halo-vest assisted internal fixation can provide good stability before operation and promote bone healing and pain relief after operation.

Objective To evaluate the clinical efficacy of a self-designed novel n-shaped aiming device in aiding the percutaneous cannulated screwing for treatment of odontoid fractures of Anderson-D' Alonzo type Ⅱ and shallow type Ⅲ.Methods A retrospective analysis was conducted of the 17 patients who had been treated at our department for odontoid fracture of Anderson-D' Alonzo type Ⅱ and shallow type Ⅲ between January 2009 and December 2013.They were 13 males and 4 females,with an average age of 37.5 years (from 16 to 61 years).All received surgical treatment after skull traction or jaw pillow traction preoperatively for reduction.Intraoperatively,percutaneous cannulated screwing via the anterior cervical approach was performed with the help of a self-designed novel n-shaped aiming device to fix the odontoid.Postoperatively,X-ray and CT scan were used to check the screw locations and evaluate the fracture healing.Results The 17 cases were followed up for 6 to 15 months (average,10.5 months).No intraoperative injury to the esophagus,artery,spinal cord or nerve root happened.The operating time ranged from 60 to 125 min.The bleeding was from 10 to 40 mL.Intraoperative observation revealed fine locations of the screws.Bony union was achieved in 16 cases 3 months postoperatively while separation and hardening of the fracture ends was found in one ease.Conclusion Our self-designed novel n-shaped aiming device can facilitate the percutaneous cannulated screwing for treatment of odontoid fractures of Anderson-D'Alonzo type Ⅱ and shallow type Ⅲ,given that it has advantages of simple manipulation,accurate insertion,minimal invasion,quick recovery and reliable efficacy.

Objeetive To assess the study outcomes in a consecutive series of patients with thoracic disc herniation (TDH) who undergone posterior spinal canal decompression and discectomy with segmental instrumentation and fusion.Methods Between January 2005 and June 2012,the data of 17 patients (11 males and 6 females) was retrospectively reviewed and analyzed.Disc herniation was classified as central in 10 cases and paracentral in 7 cases.The average canal encroachment was 71.7％±9.6％ (range,52％ to 90％).Their mean age at surgery was 55.7 years (range,21 to 81 years).All patients underwent a transfacet decompression and segmental instrumentation with interbody fusion.The data of patients included clinical presentation,blood loss,operative time,complications,visual analogue scale (VAS),Japanese Orthopaedic Association (JOA) score,and Frankel grading system.Results The average follow-up period was 37±12 months.The average surgical time was 120±63 min.The mean blood loss was 471±198 ml.Mean preoperative VAS score was 8.01±0.21,which improved to a mean of 1.12±0.07 at final follow-up.Average pre-and post-operative at 12 months JOA scores were 3.17±0.83 and 8.78±0.94 points,respectively.The average recovery rate was 65.1％±23.4％.Overall JOA scores showed a significant postoperative improvement.All patients reported 1 or 2 grade improvement in Frankel grading compared with preoperative status except for 1 patient whose grade had not changed.There were three complications,including one patient developing postoperative wound infection,one experiencing a cerebrospinal fluid leakage,one developing further neurological deterioration.Conclusion The results suggested that the posterior approach using special shaped osteotomy is feasible for central calcified TDH.No major complications occurred for achieving adequate decompression for central calcified TDH.

Objective To evaluate the efficacy of unilateral open door laminoplasty and individualized cervical pedicle screw fixation for multisegmental cervical spondylotic myelopathy with flexibility type kyphosis.Methods Twenty one cases of multisegmental cervical spondylotic myelopathy with flexibility type kyphosis received surgical treatment.Unilateral open door laminoplasty and individualized cervical pedicle screw fixation.The Japanese Orthopaedic Association ( JOA) scoring system and disability index ( NDI) were applied to evaluate the neurological function and axial neck /shoulder pain before and after surgery.The Borden′method was employed to measure the cervical curvature.CT plain scan of cervical pedicle and sagittal two-dimensional imaging of transpedicular on the axial was examined.The unilateral open door laminoplasty and individualized cervical pedicle screw fixation was performed .Results A total of 168 pedicle screws were fixed successfully in 21 patients, the accuracy of screw placement reached 93.5%.The cervical curvature measured by Borden′method showed significant differences before and after operation.Compare to those before surgery , the JOA scores at 1 week after operation and at final follow-up were decreased and NDI scores were significant increased ( P <0.05 ).Conclusion Unilateral open door laminoplasty and individualized cervical pedicle screw fixation is effective for treatment of multisegmental cervical spondylotic myelopathy with flexibility type kyphosis.

Objective To investigate the clinical effect of percutaneous kyphoplasty (PKP) in treatment of osteoporotic vertebral fractures and collapse with intravertebral vacuum sign.Methods A retrospective study was conducted on the clinical and radiological data of 31 patients with osteoporotic vertebral fractures and collapse with intravertebral vacuum sign treated by PKP from June 2009 to June 2011.Vertebrae body variation,visual analog scale (VAS) and Oswestry disability index (ODI) before operation,during follow-up at postoperative one week and at postoperative 3-6 months were used as outcome measurements.Results All the patients went through operations successfully and presented significant mitigation of low back pain in 24 hours after operation.The vertebrae body height at postoperative one week [(17.2 ±4.2) mm] and at postoperative 3-6 months [(16.8 ±5.1)mm] were statistically different from that before operation [(11.4 ± 1.7) mm,P ＜0.01],while there was no statistical difference between the two follow-ups (P ＞ 0.05).VAS and ODI at postoperative one week [(2.8 ± 1.7) points and (31.6 ± 8.4) points] were statistically different from those before operation [(8.6 ± 1.3) points and (78.3 ±8.5) points,P＜0.01].VAS and ODI at postoperative 3-6 months [(2.3 ±0.8) points and (23.7 ± 2.3) points] presented statistical differences from those before operation (P ＜ 0.01),but no statistical differences from those at postoperative one week (P ＞ 0.05).Conclusion PKP obtains satisfactory clinical outcomes,for it relieves low back pain and restores vertebral body height.

ObjectiveTo evaluate the clinical effects of guiding apparatus assisted individual posterior cervical pedicle screw fixation technique.MethodsThe study enrolled 24 patients treated with posterior cervical decompressive single open-door laminoplasty and transpedicular screw-rod fixation from January 2008 to December 2010.The point of screw penetration and screw path direction were confirmed by measuring the transverse nail angle (TNA) and sagittal nail angle (SNA) of nail channel on the pre-operative CT plain scan of cervical pedicle and sagittal two-dimensional imaging of transpedicular axis.According to the results of CT measurement,individual cervical pedicle screw was implanted with the assistance of self-made guiding apparatus and then fixed after decompression.Transverse screw angle ( TSA ) and sagittal screw angle ( SSA ) were determined on the CT scan of cervical pedicle and sagittal two-dimensional imaging of transpedicular axis one week postoperatively in order to analyze the accuracy of placement of pedicle screws.Periodical anteroposterior and lateral X-ray radiographs of cervical vertebra were taken postoperatively to detect the stabilization of internal fixation.ResultsA total of 223 pedicle screws were inserted successfully into the C3 ～ C7,of which 220 crews were inserted accurately but three had slight inclination according to the postoperative CT,with placement accuracy of 98.7％.The comparison between inclination angle of inserted screws and that of preoperative transpedicular axis showed insignificant statistical difference ( P ＞ 0.05 ).All the patients were followed up for 6-34 months ( mean,18.5 months),which showed no neurovascular complications related to screws perforation out of pedicle cortex or no screw loosening,prolapse or breakage.ConclusionPosterior cervical pedicle screw insertionperformed according to the individual CT measurement is easy and safe and has a high accuracy rate under the assistance of self-made guiding apparatus.

Objective To evaluate the clinical effect of the cannulated screw fixation in treatment of the dens fracture under locational guidance. Methods The study involved 27 patients treated with the cannulated screw fixation under locational guidance from January 2005 to January 2009.There were 19 patients with type II fracture and eight with type light m fracture.The lateral and open mouth position X-ray examination of the cervical ventebrae was done to observe the fracture healing. Results The operation lasted for a range of 40 minutes to 1.3 hour (average 1.0 hour),which showed no any complications.The patients were followed up for average 6.5 months(3-12 months),which showed sound fracture healing in 26 patients but nonhealing in one. Conclusion The cannulated screw fixation for treatment of the dens fracture under locational guidance is characterized by easy operation,minor trauma and satisfactory outcome.