Factors associated with non-fusion after direct pars repair of lumbar spondylolysis with pedicle screw and lamina hook: a clinical and CT-assessed study.

BACKGROUND: Pedicle screw and lamina hook (PSLH) technique is an effective and popular method for direct pars repair of lumbar spondylolysis. There is a lack of studies to explore factors that may influence the healing of spondylolysis after direct pars repair surgery. The present study aimed to investigate the factors associated with non-fusion after direct pars repair of lumbar spondylolysis with PSLH technique. METHODS: A total of 55 subjects (average age 21.1 ± 6.3 years, a total of 120 pars defects) diagnosed with symptomatic spondylolysis and underwent pars repair surgery with PSLH were followed up and their clinical data were analyzed. Subjects were divided into a non-fusion group and fusion group according to whether the pars defect had bony fusion at last follow-up assessed by CT. Radiographic data, data related to spondylolysis and clinical outcomes were collected and compared between groups. RESULTS: The mean follow-up time of the 55 patients was 24.8 ± 12.0 (12-64) months. Among the 120 pars defects, 101 defects were successfully fused and 19 were not fused according to CT. The fusion rate was 84.2%. Multivariable logistic regression analysis showed the factors correlated with non-fusion after pars repair surgery: whether the spondylolysis segment was associated with spina bifida occulta (SBO) (P = 0.001), stage of the defect (P = 0.047), width of the defect (P = 0.002), and disc degeneration (P = 0.014). CONCLUSION: Direct pars repair by PSHL is a reliable treatment for lumbar spondylolysis with a fusion rate of 84.2%. Association with SBO of the spondylolysis segment, a terminal stage of the defect, a wider defect gap, and grade III disc degeneration may be factors associated with non-fusion after direct pars repair of lumbar spondylolysis with PLSH. Non-fusion patients after pars repair appear to have worse clinical results compared to fusion patients.

Robot-assisted percutaneous vertebroplasty for osteoporotic vertebral compression fractures: a retrospective matched-cohort study.

PURPOSE: This study aims to introduce the principle, clinical efficacy, and learning curve of robot-assisted percutaneous vertebroplasty (PVP). METHODS: Forty-two patients who underwent robot-assisted single-level PVP were analyzed retrospectively and 42 age-matched patients using freehand technique were selected as the control group. The visual analog scale, operation time, radiation exposure, accuracy, and learning curve were analyzed. RESULTS: The puncture time and total operation time were significantly shorter, and the puncture and total fluoroscopy number were fewer in the robot group. The deviation between pre-operative planned and actual puncture trajectory well met clinical requirement. The puncture time, total operation time, and puncture fluoroscopy number were significantly more in early cases than in later cases in the robot group. CONCLUSION: The robot-assisted pedicle puncture technique shortens the operation time and reduces radiation exposure, and the accuracy meets the clinical requirement in PVP. The learning curve is short and not steep.

Significance of body mass index on thoracic ossification of the ligamentum flavum in Chinese population.

PURPOSE: To investigate the risk factors for thoracic ossification of the ligamentum flavum (TOLF), especially the relationship between BMI and TOLF. METHODS: A total of 856 individuals consisting of 326 controls without ossification of spinal ligaments and 530 TOLF inpatients who underwent thoracic spine decompression surgery at our hospital between January 2013 and September 2020 were included. All subjects were classified into 4 grades: Grade 0) control; Grade 1) single-segment TOLF; Grade 2) multi-segment TOLF; and Grade 3) TOLF combined thoracic ossification of the posterior longitudinal ligament (T-OPLL). Logistic regression analysis was performed to identify the risk factors for TOLF. The TOLF index was calculated to assess the severity of TOLF, and its relationship with BMI was investigated by correlation analysis. RESULTS: Overall, TOLF patients are most numerous in the 50-59 age group. Age and gender were considered as independent risk factors for Grades 1 and 2. BMI was identified as an independent risk factor for TOLF. Furthermore, BMI was significantly higher in Grade 1 (26.1 VS 24.5 kg/m2, P = 0.0001), Grade 2 (28.2 VS 24.5 kg/m2, P < 0.0001), and Grade 3 (29.1 VS 24.5 kg/m2, P < 0.0001) than Grade 0. Notably, in TOLF patients without combined T-OPLL, BMI was positively correlated with TOLF index, while BMI was negatively correlated with age in younger individuals. CONCLUSION: BMI is a crucial risk factor for TOLF. It highlights the necessity of close follow-up of asymptomatic TOLF patients with high BMI to detect and treat their TOLF progression promptly.

Scoliosis in dysplastic spondylolisthesis: a clinical survey of 50 young patients.

BACKGROUND: Dysplastic spondylolisthesis is a rare spinal deformity that occurs mainly in young patients. Although its sagittal parameters had been well stated, coronal abnormalities in these patients were poorly studied. The purposes of this study were: (1) to investigate the prevalence of scoliosis in dysplastic spondylolisthesis;(2) to assess scoliosis resolution or persistence after surgery; and (3) to propose a modified classification of scoliosis associated with dysplastic spondylolisthesis. METHODS: Fifty patients (average age 14.9 ± 5.6 years) diagnosed with dysplastic spondylolisthesis who underwent surgical treatment were followed up and their data were analyzed. Standing posteroanterior and lateral full spine radiographs were used to measure the coronal and sagittal parameters. Patients with scoliosis, which was defined as a coronal Cobb angle greater than 10°, were divided into three groups according to their curve characteristics: "independent" scoliosis (IS) group, spasm scoliosis (SS) group, and olisthetic scoliosis (OS) group. SS and OS were spondylolisthesis-induced scoliosis. The radiographic parameters and patient-reported outcomes were collected before and after surgery and compared between groups. RESULTS: The average slip percentage was 62.8% ± 23.1% and the average follow-up time was 51.5 ± 36.4 months (range 3-168 months). Twenty-eight of the 50 (56%) dysplastic spondylolisthesis patients showed scoliosis, of which 8 were IS (24.7° ± 15.2°), 11 were SS (13.9° ± 3.0°), and 9 were OS (12.9° ± 1.9°). By the last follow-up, no scoliosis resolution was observed in the IS group whereas all SS patients were relieved. Of the nine patients with OS, four (44.4%) had scoliosis resolution after surgery. CONCLUSION: Distinguishing different types of scoliosis in dysplastic spondylolisthesis patients may help surgeons to plan treatment and understand prognosis. For patients with significant scoliosis, whether "independent" or spondylolisthesis-induced, treatment of spondylolisthesis should be performed first and scoliosis should be observed for a period of time and treated according to the corresponding principles.

The effect of bone cement distribution on the outcome of percutaneous Vertebroplasty: a case cohort study.

BACKGROUND: To analyze the effect of different types of bone cement distribution after percutaneous vertebroplasty (PVP) in patients with osteoporotic vertebral compression fracture (OVCF). METHODS: One hundred thirty seven patients with single level OVCF who underwent PVP were retrospectively analyzed. The patients were divided into two groups according to bone cement distribution. Group A: bone cement contacted both upper and lower endplates; Group B: bone cement missed at least one endplate. Group B was divided into 3 subgroups. Group B1: bone cement only contacted the upper endplates; Group B2: bone cement only contacted the lower endplates; Group B3: bone cement only located in the middle of vertebral body. The visual analogue scale (VAS) score at 24 h post operation and last follow-up, anterior vertebral height restoration ratio (AVHRR), anterior vertebral height loss ratio (AVHLR), local kyphotic angle change and vertebral body recompression rate were compared. RESULTS: 24 h post operation, the pain of all groups were significantly improved. The average follow-up time was 15.3 ± 6.3 (6-24) months. At last follow-up, the VAS score of group A was lower than that of group B. There were 14 cases (10.2%) of adjacent vertebral fracture, 5 cases (8.6%) in group A and 9 cases (11.4%) in group B. There were 9 cases (6.6%) of cement leakage, 4 cases (6.9%) in group A and 5 cases (6.3%) in group B. At last follow-up, there were 16 cases (11.7%) of vertebral body recompression, including 3 cases (5.2%) in group A and 13 cases (16.5%) in group B. There was no significant difference in AVHRR between two groups. Local kyphotic angle change was significant larger in group B. At last follow-up, AVHLR in group B was higher than that in group A. Analysis in subgroup B revealed no significant difference in VAS score, local kyphotic angle change, vertebral recompression rate, AVHRR or AVHLR. CONCLUSIONS: If the bone cement fully contacted both the upper and lower endplates, it can better restore the strength of the vertebral body and maintain the height of the vertebral body, reduce the risk of the vertebral body recompression and long-term pain.

MiR-199b-5p inhibits osteogenic differentiation in ligamentum flavum cells by targeting JAG1 and modulating the Notch signalling pathway.

Ossification of the ligamentum flavum (OLF) is a pathology almost only reported in East Asian countries. The leading cause of OLF is thoracic spinal canal stenosis and myelopathy. In this study, the role of miR-199b-5p and jagged 1 (JAG1) in primary ligamentum flavum cell osteogenesis was examined. MiR-199b-5p was found to be down-regulated during osteogenic differentiation in ligamentum flavum cells, while miR-199b-5p overexpression inhibited osteogenic differentiation. In addition, JAG1 was found to be up-regulated during osteogenic differentiation in ligamentum flavum cells, while JAG1 knockdown via RNA interference caused an inhibition of Notch signalling and osteogenic differentiation. Moreover, target prediction analysis and dual luciferase reporter assays supported the notion that JAG1 was a direct target of miR-199b-5p, with miR-199b-5p found to down-regulate both JAG1 and Notch. Further, JAG1 knockdown was demonstrated to block the effect of miR-199b-5p inhibition. These findings imply that miR-199b-5p performs an inhibitory role in osteogenic differentiation in ligamentum flavum cells by potentially targeting JAG1 and influencing the Notch signalling pathway.

Posterior corrective surgery for moderate to severe focal kyphosis in the thoracolumbar spine: 57 cases with minimum 3 years follow-up.

PURPOSE: To evaluate the radiological and clinical outcomes of the corrective surgery for patients with moderate to severe focal kyphosis in thoracolumbar spine. METHODS: Fifty-seven patients with moderate to severe focal kyphosis of the thoracolumbar spine underwent apical segmental resection osteotomy with dual axial rotation correction at our hospital. There were 30 male and 27 female patients. The mean age was 34.3 years. The kyphosis level radiographs were obtained from each patient before surgery, immediately after surgery and at follow-up. Local kyphosis and scoliosis Cobb angles were measured. Full-spine standing radiographs were obtained before surgery and at follow-up, and the spine sagittal and coronal balance were evaluated. The height of patients, the Frankel grading system for neurological functions, the Oswestry disability index for life quality, the visual analogue score for back pain and the patient satisfactory index for satisfaction to surgery were applied before surgery and at follow-up. The radiological and clinical outcomes were further analyzed in different sub-groups of patients according to etiology, severity of kyphosis, age, level of kyphosis apex, Frankel grade before surgery, and complications. RESULTS: The average follow-up time of patients was 46.1 months. The average kyphosis angle reduced from 94.6° before surgery to 31.0° immediately after surgery, and remained at 34.4° at follow-up. The sagittal balance of the spine, height of patients, Frankel grading, Oswestry disability index and visual analogue score were improved. The patient satisfactory index (PSI) showed a satisfied rate of 91.2%. The correction rate was significantly higher in patients with kyphosis angle less than 95° and age less than 35 years. The clinical improvement rate was significantly higher in patient with kyphosis apex at lower thoracic spine or thoracolumbar segment, Frankel grade E before surgery and no complication group. The incidence of intra-operative and early stage complications was 38.6%, and the incidence of instrumentation failure was 10.5%. The most severe complication was transient spinal cord injury, and the incidence was 7.0%. All complications got good relief after appropriate intervention. CONCLUSIONS: Apical segmental resection osteotomy with dual axial rotation correction is an effective procedure to treat moderate to severe focal kyphosis, the prevention of serious neurological complications is fundamental to achieve the ideal clinical results.

[Analysis of risk factors for deep surgical site infection after posterior thoracic and lumbar surgery].

OBJECTIVE: To study the risk factors for deep surgical site infection after posterior thoracic and lumbar surgery. METHODS: The medical data of the patients with deep surgical site infection after posterior thoracic and lumbar surgery from January 2008 to December 2013 were reviewed.For each case patient, 3 non-infected controls were randomly selected from the same database of all patients who underwent posterior thoracic and lumbar surgery.Patients who had diagnosis of spinal fractures, infection, tuberculosis, and tumor were excluded. The microbiology and related factors were collected and analyzed. T-test, χ2 test and Logistic analysis were used to analyze the data, respectively. RESULTS: Ninety-nine cases were identified (infection group), 57 men and 42 women, average 54.5 years old, average body mass index 26.4 kg/m2. Fifty-five (55.6%) patients were identified with organisms, and the most common identified organism was Staphylococcus Aureus. Compared with the cases in the control group (44.4 g/L), the cases in the infection group (43.1 g/L) had a significant low albumin preoperatively (P=0.001). Multivariate Logistic analysis showed that obesity (OR=2.102, 95% CI=1.259-3.508), diabetes (OR=1.926, 95% CI=1.041-3.563), number of surgical levels≥3 (OR=1.985, 95% CI=1.130-3.486) were risk factors for this complication (P<0.05). CONCLUSION: For deep surgical site infection after posterior thoracic and lumbar surgery, obesity, diabetes, preoperative low albumin and number of surgical levels≥3 are risk factors.

The posterior surgical treatment for focal kyphosis in upper-middle thoracic spine.

PURPOSE: To analyze the clinical characteristics of focal kyphosis in upper thoracic spine, and observe the outcome of the posterior corrective surgical procedures. METHODS: Thirteen patients of focal kyphosis were treated with posterior surgical procedures in our medical center. The kyphosis apex was above T6 in all cases. The surgical procedures performed in this study included pedicle subtraction osteotomy (PSO) in six cases and vertebral column resection (VCR) in seven cases. For each case, the kyphosis angle, curvature of lower thoracic spine, lumbar lordosis angle, cervical lordosis angle, pelvic parameters, and the sagittal plane balance of the spine were compared before and after surgery. Neurological function change was assessed based on Frankel grading system and oswestry disability index (ODI). RESULTS: The average follow-up time of this study was 28.3 months. The average kyphosis angle was reduced from 73.5º before surgery to 32.7º immediately after surgery, and remained at 33.5º at follow-up. The average ODI improved from 22.5 before surgery to 15.5 at follow-up. The neurological function improved after surgery in eight cases. There were two cases of transient neurological deficiency in the lower extremities after VCR procedure, who eventually recovered under postoperative care. One case had recurrent kyphosis due to implant failure after VCR procedure, and recovered after the revision surgery. CONCLUSIONS: Although high risk needs to be warned, the corrective surgery for focal kyphosis in upper thoracic spine still can achieve satisfactory results. Given the comparative surgical results yet less complications, PSO seems to be a preferable procedure over VCR for kyphosis at this region.

Circumspinal decompression and fusion through a posterior midline incision to treat central calcified thoracolumbar disc herniation: a minimal 2-year follow-up study with reconstruction CT.

PURPOSE: There have been several surgical approaches used in the treatment of thoracolumbar disc herniation (TLDH) from T10/11 to L1/2. However, central calcified TLDH cases are still challenging to spine surgeons. The anterior transthoracic approaches and lateral/posterolateral approaches are all essentially performed from one side; thus, the compressive lesion and the dura matter on the other side of the spinal canal are not clearly visualized, predisposing the procedure to incomplete decompression or inadvertent cord manipulation. Moreover, a number of these approaches are technically demanding and require entry into the chest. The purpose of this study was to introduce a new surgical procedure-circumspinal decompression and fusion through a posterior midline incision-for the treatment of central calcified TLDH and to evaluate its surgical outcome. METHODS: In this study, 22 patients (15 males and 7 females; mean age 49 years) with central calcified TLDH underwent this procedure between April 2008 and April 2011. Altogether, 26 discs were excised, with two discs at T10/11, eight discs at T11/12, nine discs at T12/L1 and seven discs at L1/2. Of these patients, 16 returned for final follow-up, with a mean follow-up period of 41 months (range 24-57 months). Clinical outcomes, including operative time, blood loss, perioperative complications, post-operative time of hospitalization, neurological status improvement, extent of decompression, back pain, local spinal curvature and fusion, were investigated. The patients' neurological status was evaluated by a modified Japanese Orthopedic Association scoring system of 11 points. Fusion and the extent of decompression were evaluated by reconstruction CT at final follow-up. RESULTS: The mean operative time was 185 min, the mean blood loss was 896 ml and the mean post-operative hospitalization time was 8 days. Four patients suffered perioperative complications, but only two were related to dura violation and none involved the respiratory system. All of the 16 patients who returned for the final follow-up showed improvement, and evidence of improvement was found in five of the other six patients who did not return for final follow-up through telephone interview or earlier follow-up evaluations. Complete decompression was achieved in 12 of the 16 patients who returned for final follow-up. In the 16 patients who returned for final follow-up, back pain was significantly reduced and local spinal curvature remained unaltered. In addition, based on reconstruction CT images, solid fusion was observed in 15 of the 16 patients who returned for final follow-up. CONCLUSIONS: The circumspinal decompression and fusion through a posterior midline incision procedure can be used to treat central calcified TLDH patients with neurological deficits. This method's greatest advantage is that it is a highly effective and safe procedure for decompression. Although it is a major and destructive procedure, spinal stability was well maintained in most of the cases. In this era when minimally invasive spine surgeries like thoracoscopy have been in an upward trajectory, spine surgeons still should be made aware of this procedure.

[The treatment of severe lumbar dysplastic spondylolisthesis].

OBJECTIVE: To summarize the clinical characteristics of severe lumbar dysplastic spondylolisthesis, and to investigate the effectiveness of the posterior surgery including decompression, partial reduction with instrumentations and interbody fusion. METHODS: Twelve patients of severe lumbar dysplastic spondylolisthesis treated between March 2007 and February 2012 were studied retrospectively. Twelve patients include 10 female and 2 male patients with an average age of 10.7 years (9-17 years). All of their spondylolisthetic level was L5 vertebrae. None of them were effective after regular conservative treatment. Eleven of 12 patients were treated surgically through a posterior decompression and instrumented reduction. One case was treated by L5 vertebrectomy and reduction of L4 onto sacrum. Their levels of instrumentations were L4-S1 in 8 patients and L5-S1 in 4 patients. All of 12 patients were fused via interbody fusion. The visual analog scale(VAS), Oswestry disability index (ODI), Japanese Orthopaedic Association(JOA) score, slip angle, percentage slip, lumbar lordosis, sagittal balance were used as outcome measures. RESULTS: All of these patients were followed up regularly with an average follow-up of 32 months (6-64 months). Five of these 12 patients suffered postoperative nerve root impairment, including impairment of unilateral and bilateral L5 nerve roots. At the latest follow-up, only 1 case was still suffering from the weakness of unilateral peroneal long and short muscles, the other 4 patients recovered totally. The degree of their spondylolisthesis was reduced II degrees or more, and their slip angles decreased from 35.6 degree preoperatively to 9.8 degree postoperatively. The VAS, ODI , JOA, lumbar lordosis and sagittal balance were improved postoperatively. No instrumentation loosening or rupture was found. CONCLUSIONS: In patients with severe lumbar dysplastic spondylolisthesis, isolated posterior decompression, reduction with internal fixation may lead to a satisfactory clinical outcomes. Surgical reduction is helpful to improve the interbody contact area, thus possibly improve the fusion rate. At the same time, reduction may reduce or correct the lumbar-sacral kyphosis, recover the normal lumbar lordosis and normal sagittal alignment with an excellent cosmetic result. The incidence of the postoperative nerve impairment is high because of the stretching of L5 nerve roots secondary to the reduction, but most of the patients with postoperative nerve impairment may recover gradually.

Posterior thoracic antedisplacement and fusion surgery for a special type of ossification of the posterior longitudinal ligament in the thoracic spine: indications and preliminary clinical results of 2-year follow-up.

OBJECTIVES: To describe a novel technique, posterior thoracic antedisplacement and fusion (PTAF), for a special type of ossification of the posterior longitudinal ligament in the thoracic spine (T-OPLL), and to evaluate its safety and efficacy. METHODS: From July to December 2020, five consecutive patients with beak-type T-OPLL located at the thoracic vertebral body (VB) level underwent PTAF surgery. Their demographic data, radiological parameters, perioperative complications, and surgery-related findings were recorded and analyzed. The surgical outcomes were assessed using a modified Japanese Orthopedic Association (mJOA) scale, and the recovery rate (RR) was calculated using the Hirabayashi's method. RESULTS: All patients were followed up for at least two years. The mean thickness of OPLL was 9.4 ± 1.0 mm, and the OPLL spinal canal occupying ratio was 67.7% ± 8.5%. Postoperatively, the mean antedisplacement distance of OPLL was 8.1 ± 1.8 mm, and the average shortened distance of the spinal column was 6.0 ± 1.13 mm. The mean operation time and blood loss were 158.2 ± 26.3 min and 460 ± 89.4 mL, respectively. Perioperative complications were cerebrospinal fluid leakage and instrument failure, 2 cases each. The mean mJOA score was increased from 3.6 ± 2.9 before surgery to 9.4 ± 3.0 at the last follow-up, and the average RR was 84.2 ± 30.5%. CONCLUSION: The preliminary clinical outcomes indicate that PTAF is a safe and effective method for the treatment of beak-type T-OPLL, which has its apex located at the VB level and has a high spinal canal occupation ratio.

The posterior surgical correction of congenital kyphosis and kyphoscoliosis: 23 cases with minimum 2 years follow-up.

PURPOSE: The purpose of this study is to review our operative experience of congenital kyphosis or kyphoscoliosis undergoing either pedicle subtraction osteotomy (PSO) or posterior vertebral column resection (pVCR) according to certain criteria we have established. METHODS: From December 2003 to 2009, 23 consecutive patients of congenital kyphosis or kyphoscoliosis were treated by means of PSO or pVCR procedure in a single institution. The average preoperative kyphosis angle was 74.3º. The C7 plumb line was 12.6 mm posterior to the posterior-superior corner of S1 on average, showing negative imbalance. In the 11 cases who had accompanied scoliosis, the average preoperative scoliosis angle was 42.6º. The average Oswestry Deficiency Index (ODI) for back pain was 14.6 before surgery. Eleven patients had compromise of neurological functions. RESULTS: After PSO or pVCR procedure, the average kyphosis angle decreased to 20.0º, and the accompanied scoliosis also decreased to 15.8º. The average follow-up time after surgery was 34.3 months. At the last follow-up, the average kyphosis corrective rate was 73.7 %, and the average scoliosis corrective rate was 61.7 %. The negative imbalance improved, with the C7 plumb line being 1.5 mm posterior to the posterior-superior corner of S1 on average. After surgery, the average ODI for back pain had 40.6 % improvement, and most patients who had neurological symptoms before surgery had varying degrees of relief. The total satisfactory rate to corrective surgery was 91.3 %. No permanent neurological damage was observed. CONCLUSIONS: If selected appropriately, both PSO and pVCR procedures can achieve compatible and satisfactory correction results in the surgical treatment of congenital kyphosis or kyphoscoliosis.

Complications of correction for focal kyphosis after posterior osteotomy and the corresponding management.

STUDY DESIGN: A clinical retrospective study. OBJECTIVE: To analyze the complications and relevant management of the correction procedure for focal kyphosis. SUMMARY OF BACKGROUND DATA: The treatment of focal kyphosis is a difficult problem in spine surgery. The potential complications of surgery should be considered cautiously and managed positively. METHODS: Eighty-one patients with focal kyphosis were treated by posterior osteotomy and correction. The etiology was posttraumatic in 31 cases, healed tuberculosis in 31 cases, congenital in 17 cases, and iatrogenic in 2 cases. The surgical procedures were pedicle subtraction osteotomy in 19 cases, posterior osteotomy with anterior opening-posterior closing correction in 23 cases, and posterior vertebral column resection with dual axial rotation correction in 39 cases. The intraoperative and postoperative complications were summarized, and the corresponding management was described in detail. RESULTS: The average follow-up time was 31 months. Among patients who underwent pedicle subtraction osteotomy, the intraoperative and postoperative complications included 3 cases of dural tear and 1 case of wound infection. For posterior osteotomy with anterior opening-posterior closing correction, the complications included 4 cases of dural tear, 1 case of wound infection, and 1 case of instrumentation loosening and recurrence of kyphosis . For posterior vertebral column resection with dual axial rotation correction, the complications included 3 cases of dural tear, 5 cases of nerve root injury, 1 case of titanium mesh loosening, 1 case of osteotomy segment migration, 2 cases of transient neurological compromise, and 1 case of instrumentation loosening and kyphosis recurrence. All the complications were treated positively and pertinently. CONCLUSIONS: During the posterior osteotomy and correction of focal kyphosis, the risk of surgery increases along with the more severe deformity and the more complicated surgical procedure. However, most complications do not significantly affect the outcome if treated appropriately.

Posterior surgical correction of posttraumatic kyphosis of the thoracolumbar segment.

OBJECTIVES: To analyze the clinical characteristics and surgical results of posttraumatic kyphosis of the thoracolumbar segment. METHODS: Thirty-four patients with posttraumatic kyphosis of the thoracolumbar segment underwent posterior osteotomy, kyphosis correction, and fixation at our hospital. The kyphosis apex was from T10 to L2. There were 15 male and 19 female patients. The mean age was 48.9 years. Full-spine standing radiographs were obtained before surgery, after surgery, and at follow-up. The sagittal spine balance status was evaluated, and the kyphotic angle, the lumbar lordotic angle, and the thoracic kyphotic angle were measured. The Frankel grading system for neurological functions and the Visual Analogue Scale for back pain were evaluated before surgery and at follow-up. The Oswestry Disability Index was applied for assessment of life quality and surgical results of patients. The Patient Satisfied Index (PSI) was also used for determination of surgical results. Patients were grouped according to the extent of kyphotic angle and the surgical technique. The difference in kyphosis correction and back pain between groups was observed before and after surgery. Relief from neurological symptoms was also observed. RESULTS: The average kyphotic angle was 48.5 degrees, the average lumbar lordotic angle was 57.9 degrees, and the average thoracic kyphotic angle was 11.4 degrees before surgery. The sagittal spine balance was well maintained in 14 cases, and negative imbalance and positive imbalance were seen in 13 cases and 7 cases, respectively. There was significant difference in back pain between patients in the abnormal and normal groups of the lumbar lordotic angle. The average follow-up time after surgery was 32.1 months. The average kyphotic angle correction rate was 90.4% after surgery and 87.2% at follow-up. The average Oswestry Disability Index was 50.4% before surgery, which improved to 29.4% at follow-up, with an improvement rate of 41.5%. The Patient Satisfied Index result showed a total satisfactory rate of 94.1%. There were 16 cases of neurological deficit before surgery; 8 of them achieved various degrees of improvement after surgery. CONCLUSIONS: Surgical correction of posttraumatic kyphosis of the thoracolumbar segment can show good radiologic and clinical results with the appropriate procedure according to the extent of the kyphosis angle. Some patients with neurological deficit are still worthy of surgical treatment.

Factors Affecting the Surgical Outcomes of Patients Treated With "de-tension" Surgical Strategy for Multilevel Ossification of the Posterior Longitudinal Ligament in the Thoracic Spine: A Minimum 2-year Follow-Up Study of 83 Patients in a Single Center.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To describe the clinical characteristics and surgical outcomes of patients with multilevel-ossification of the posterior longitudinal ligament (mT-OPLL), and to identify risk factors for unfavorable outcomes. METHODS: Patients who were diagnosed with mT-OPLL and underwent one-stage thoracic posterior laminectomy combined with selective OPLL resection, spinal cord de-tension, and fusion surgery between August 2012 and October 2020 were recruited. Patients' demographic-, surgical- and radiological-related parameters were collected and analyzed. Neurological status was evaluated with mJOA score, and recovery rate (RR) was calculated using the Hirabayashi formula. According to RR, patients were divided into a favorable outcome group (FOG, RR ≥50%) and an unfavorable outcome group (UOG, RR <50%). Univariate and multivariate analyses were used to compare the difference between the 2 groups and to identify risk factors for unfavorable outcomes. RESULTS: A total of 83 patients were included, with an average age of 50.6 ± 8.3 years. Cerebrospinal fluid leakage (60.2%) and transient neurological deterioration (9.6%) were the most common complications. The average mJOA score improved from preoperative 4.3 ± 2.2 to 9.0 ± 2.4 at the last follow-up, and the mean RR was 74.9 ± 26.3%. Disease duration, preoperative nonambulatory status, and the number of decompressed levels were identified as potential risk factors by Univariate analysis (all P < .05). Multivariate analysis showed that the preoperative disease duration and nonambulatory status were independent risk factors for unfavorable outcomes. CONCLUSIONS: Long disease duration and nonambulatory status before surgery were independent risk factors for unfavorable outcomes.

Risk Factors and Three Radiological Predictor Models for the Progression of Proximal Junctional Kyphosis in Adult Degenerative Scoliosis Following Posterior Corrective Surgery: 113 Cases With 2-years Minimum Follow-Up.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To identify risk factors and predictive models for proximal junctional kyphosis (PJK) in a long-term follow-up of patients with adult degenerative scoliosis (ADS) following posterior corrective surgeries. MATERIALS AND METHODS: A consecutive 113 ADS patients undergoing posterior corrective surgery between January 2008 and April 2019 with minimum 2-year follow-up were included. All patients underwent preoperative, postoperative, and final follow-up by X-ray imaging. Multivariate logistic analysis was performed on various risk factors and radiological predictor models. RESULTS: PJK was identified radiographically in 46.9% of patients. Potential risk factors for PJK included postoperative thoracic kyphosis (TK) (P < .05), final follow-up Pelvic Tilt (PT) (P < .05), PT changes at final follow-up (P < .05), age over 55 years old at the surgery (P < .05), theoretical thoracic kyphosis-actual thoracic kyphosis mismatch (TK mismatch) (P < .05) and theoretical lumbar lordosis-acutal lumbar lordosis mismatch (LL mismatch) (P < .05). As for the predictive models, PJK was predictive by the following indicators: preoperative global sagittal alignment ≥45° (Model 1), postoperative pelvic incidence-lumbar lordosis mismatch (PI-LL)≤10° and postoperative PI-LL overcorrection (Model 2), and TK+LL≥0° (Model 3) (P < .05). Postoperative TK mismatch (OR = 1.064) was independent as risk factors for PJK, with the cut-off values respectively set at -28.56° to predict occurrence of PJK. CONCLUSION: The risk of radiographic PJK increases with an age over 55 years old and higher postoperative TK. In addition, postoperative TK mismatch is an independent risk factor for developing PJK. All three predictive models could effectively indicate the occurrence of PJK.

[The posterior surgical treatment of old tuberculous kyphosis].

OBJECTIVE: To observe the results of posterior osteotomy and correction in the surgical treatment of old tuberculous kyphosis. METHODS: From June 2004 to December 2008, 31 cases of old tuberculous kyphosis with posterior osteotomy and correction technique were treated. There were 12 cases of male and 19 cases of female. The average age was 33.4 years. Pedicle subtraction osteotomy or vertebral column resection were applied in surgery. The kyphosis angle, lumbar lordosis angle and sagittal balance condition of the spine were measured before and after surgery, as well as follow-up. The Frankel grading system for neurological function of lower extremities, the Oswestry disability index (ODI) for life quality, and patient satisfactory index (PSI) for satisfaction of surgery were applied before surgery and at follow-up. RESULTS: The average kyphosis angle was 94° ± 27°, the average lumbar lordosis angle was 71° ± 20°, and the average sagittal C(7) plumb line was (-15 ± 44) mm away from the balance region before surgery. The average kyphosis angle decreased to 26° ± 11° in one week after surgery, with an improvement rate of 71.4%. The average follow-up time was 22.5 months. The average kyphosis angle was 28° ± 12° at the final follow-up, with an improvement rate of 70.0%. The average lumbar lordosis angle was 46° ± 11°, with an improvement rate of 35.1%. The postoperative kyphosis angle and lumbar lordosis angle were significantly different with that of pre-operation (for kyphosis angle: t = 16.3, P < 0.05; for lumbar lordosis angle: t = 8.1, P < 0.05). The average sagittal C(7) plumb line was (-4 ± 22) mm away from the balance region at the final follow-up, with an improvement rate of 73.4%. The Frankel grading were E in 13 cases, D in 13 cases, and C in 5 cases before surgery, and were E in 20 cases, D in 8 cases, and C in 3 cases at the final follow-up. The average ODI was 13 ± 12 before surgery, and was 7 ± 8 at the final follow-up, with an improvement rate of 45.2%. The PSI results showed a satisfied rate of 90.3%. CONCLUSION: Good results can be achieved by applying proper posterior osteotomy and correction technique according to the severity of old tuberculous kyphosis.

[Longterm outcome after the decompressive surgery for thoracic myelopathy due to the ossification of the ligamentum flavum].

OBJECTIVES: To investigate the long-term surgical outcome of thoracic myelopathy caused by the ossification of the ligamentum flavum (OLF) and evaluate the related risk factors. METHODS: Forty-four patients who underwent decompressive laminectomy with thoracic OLF between January 1990 and December 2005 and got more than 5 years follow-up were retrospectively reviewed. Among these 44 cases, there were 29 male and 15 female whose ages at operation were 52 years averagely (27-68 years). The 2-year follow-up results and long-term outcomes were classified according to the modified Epstein's standard, and then the rates of excellent or good (REG) were calculated. The correlation between the long-term REG and the patients' ages, durations of symptoms, decompressed levels, and dural leak were analyzed. RESULTS: The mean follow-up period of these 44 cases was 8.5 years (5-19 years). The REG at 2 years after laminectomy was 77.3% (34/44), while the long-term REG was 65.9% (29/44). There was one case who had suffered from an acute spinal cord injury got a poor post-operative outcome. The other 43 cases had chronic durations, including 22 cases whose pre-operative durations of symptoms were less than 12 months and 21 cases whose durations were equal to or more than 12 months. And the long-term REG of these two groups were 77.3% (17/22) and 57.1% (12/21) respectively (P>0.05). The REG of those cases whose decompression levels were limited in T1-T9 was 78.9% (15/19), while that of those cases whose laminectomy was relevant to thoracolumbar segment (T10-L2) was 58.3% (14/24) (P>0.05). There were 7 cases who had excellent or good short-term results and poor long-term outcomes. The reasons of these changes included coexistence of lumbar spinal stenosis in three cases and the growth of the OLF at the adjacent levels in four cases. CONCLUSIONS: Although the short-term results of the decompressive surgery for thoracic OLF is good, the regular long-term follow-up is necessary because the symptoms may reoccur or deteriorate secondary to lumbar spinal stenosis or the growth of OLF at the adjacent levels near former decompressive levels; the duration of symptoms which is more than one year and the decompression levels that is involved to T10-L2 segments are possibly related to the poor long-term outcomes.

A new "de-tension"-guided surgical strategy for multilevel ossification of posterior longitudinal ligament in thoracic spine: a prospective observational study with at least 3-year follow-up.

BACKGROUND CONTEXT: Multilevel ossification of the posterior longitudinal ligament in thoracic spine (mT-OPLL) is a rare but clinically significant spinal condition. Various surgical methods have been developed to address this disease. However, the outcomes are commonly unfavorable, and no standard surgical strategy has been established. To solve this problem, we introduced a new surgical strategy based on an innovative decompression concept, namely "de-tension." PURPOSE: This study aimed to investigate the safety and efficacy of this new treatment, and to establish an improved surgical strategy. STUDY DESIGN: A prospective observational study with at least 3 years of follow-up. PATIENT SAMPLE: Fifty-one patients with consecutive mT-OPLL who were treated between August-2012 and June-2018 were enrolled in this study. OUTCOME MEASURES: A modified Japanese Orthopedic Association (mJOA) scale assessing thoracic spine, recovery rate (RR), and surgical complications. METHODS: All patients underwent 1-stage thoracic posterior laminectomy, selective OPLL resection, and spinal column shortening with/without reduction of kyphosis (dekyphosis). Initially, we recommended that when thoracic kyphosis of T1-T12 in sagittal reconstruction CT (TK) was less than 20°, no dekyphosis should be performed; when this angle was greater than 20°, dekyphosis could be conducted. Patients' demographic data, radiological findings, and intra/postoperative complications were recorded and analyzed. Neurological status was evaluated with mJOA score and RR. The correlation of preoperative TK or kyphosis angle in fusion area (FSK) with postoperative dekyphosis angle and spinal column shortening distance (SD) were respectively evaluated by Pearson correlation analysis. RESULTS: Cerebrospinal fluid leakage (58.8%) and neurological deterioration (15.7%) were the most common complications. Average mJOA score was improved from preoperative 4.0±2.1 to 8.9±2.4 at the last follow-up, and the mean RR was 71.3±33.7%. There was no correlation between preoperative TK and SD (p=.56) or between preoperative FSK and SD (p=.21), but dekyphosis angle was significantly correlated with TK (r=0.504, p<.01) and FSK (r=0.5734, p<.01). TK of 24.6° and FSK of 23.0° were determined as the critical angles for dekyphosis, and a modified surgical strategy was formulated. CONCLUSIONS: This new strategy provided a novel solution for mT-OPLL, and was proved to be safe and effective during long-term follow-up. Further rigorously designed large-scale prospective studies are needed to validate our findings.