Project description:ObjectiveTo compare the clinical outcomes and biomechanical characteristics of 1-, 2-, and 3-level pedicle subtraction osteotomy (PSO), and establish selection criteria based on preoperative radiographic parameters.MethodsPatients undergone PSO to treat ankylosing spondylitis from February 2009 to May 2019 in Sun Yat-sen Memorial Hospital of Sun Yat-sen University were enrolled. According to the quantity of osteotomy performed, the participants were divided into group A (1-level PSO, n = 24), group B (2-level PSO, n = 19), and group C (3-level PSO, n = 11). Clinical outcomes were assessed before surgery and at the final follow-up. Comparisons of the radiographic parameters and quality-of-life indicators were performed among and within these groups, and the selection criteria were established by regression. Finite element analysis was conducted to compare the biomechanical characteristics of the spine treated with different quantity of osteotomies under different working conditions.ResultsThree-level PSO improved the sagittal parameters more significantly, but resulted in longer operative time and greater blood loss (p < 0.05). Greater stress was found in the proximal screws and proximal junction area of the vertebra in the model simulating 1-level PSO. Larger stress of screws and vertebra was observed at the distal end in the model simulating 3-level PSO.ConclusionMultilevel PSO works better for larger deformity correction than single-level PSO by allowing greater sagittal parameter correction and obtaining a better distribution of stress in the hardware construct, although with longer operation time and greater blood loss. Three-level osteotomy is recommended for the patients with preoperative of global kyphosis > 85.95°, T1 pelvic angle > 62.3°, sagittal vertical alignment > 299.55 mm, and pelvic tilt+ chin-brow vertical angle > 109.6°.
Project description:Childhood spinal tuberculosis, especially when associated with severe vertebral destruction of more than two vertebral bodies can end up in severe deformity. These children show progressive deformity throughout the period of growth and can develop severe kyphosis of >100°. Such kyphosis is severely disabling with significant risk of neurological deficit and respiratory compromise. Surgical correction of these deformities by both anterior and posterior approaches has been described but each have serious limitations of approach, correctability and safety. We describe here a technique of posterior closing-anterior opening osteotomy, which allowed us to correct a rigid post-tubercular deformity of 118° in a 13-year-old boy with neglected spinal tuberculosis. The patient was a 13-year-old boy, who had contracted spinal tuberculosis at the age of 6 years. Although the disease was cured by anti-tubercular chemotherapy, he continued to deteriorate in deformity and presented to us with severe thoracolumbar kyphosis (118°). He was neurologically intact but was beginning to show shortness of breath on exertion. Patient also had fore shortening of the trunk with impingement of the rib cage on the iliac crest. Radiographs revealed complete destruction of T12, L1 and L2 vertebral bodies with the T11 vertebra fusing with L3 anteriorly. CT scans and MRI revealed severe collapse of the vertebral column and the spinal cord being stretched over the 'internal gibbus', which was formed by the remnants of the destroyed vertebrae. A single stage closing-opening osteotomy was done by a midline posterior approach with continuous intraoperative spinal cord monitoring. The procedure involved extensive laminectomy of T11-L2, pedicle screw fixation of three levels above and three levels below the apex, a wedge osteotomy at the apex of the deformity from both sides, anterior column reconstruction by appropriate-sized titanium cage and gradual correction of deformity by closing the posterior column using the cage as a fulcrum. This allowed us to achieve a correction to 38° (68% correction). There was no intraoperative or perioperative adverse event and patient had good functional and radiological outcome at 1-year follow-up. In this Grand Rounds case presentation, we have also discussed the aetiology and evolution of severe post-tubercular kyphosis, which is the most common cause of spinal deformity in the developing world. Early identification of children at risk for severe deformity, the time and ideal methods of prevention of such deformities are discussed. The pros and cons of the available options of surgical correction of established deformity and the merits of our surgical technique are discussed.
Project description:BACKGROUND:Andersson lesions (ALs), also known as spondylodiscities, destructive vertebral lesions and spinal pseudarthrosis, usually occur in patients with ankylosing spondylitis (AS). Inflammatory and traumatic causes have been proposed to define this lesion. Different surgical approaches including anterior, posterior, and combined anterior and posterior procedure have been used to address the complications, consisting of mechanical pain, kyphotic deformity, and neurologic deficits. However, the preferred surgical procedure remains controversial. The aim of this study was to illustrate the safety, efficacy, and feasibility of a modified posterior wedge osteotomy for the ALs with kyphotic deformity in AS. METHODS:From June 2008 to January 2013, 23 patients (18 males, 5 females) at an average age of 44.8 years (range 25-69 years) were surgically treated for thoracolumbar kyphosis with ALs in AS via a modified posterior wedge osteotomy in our department. All sagittal balance parameters were assessed by standing lateral radiography of the whole spine before surgery and during the follow-up period. Assessment of radiologic fusion at follow-up was based on the Bridwell interbody fusion grading system. Ankylosing spondylitis quality of life (ASQoL) and visual analog scale (VAS) scores were performed to evaluate improvements in daily life function and back pain pre-operatively and post-operatively. Paired t tests were used to compare clinical data change in parametric values before and after surgery and the Mann-Whitney U test was employed for non-parametric comparisons. The radiographic data change was evaluated by repeated measure analysis of variance. RESULTS:The mean operative duration was 205.4 min (range 115-375 min), with an average blood loss of 488.5 mL (range 215-880 mL). Radiographical and clinical outcomes were assessed after a mean of 61.4 months of follow-up. The VAS back pain and ASQoL scores improved significantly in all patients (7.52?±?1.31 vs. 1.70?±?0.70, t?=?18.30, P?<?0.001; 13.87?±?1.89 vs. 7.22?±?1.24, t?=?18.53, P?<?0.001, respectively). The thoracolumbar kyphosis (TLK) changed from 40.03?±?17.61° pre-operatively to 13.86?±?6.65° post-operatively, and 28.45?±?6.63° at final follow-up (F?=?57.54, P?<?0.001), the thoracic kyphosis (TK) changed from 52.30?±?17.62° pre-operatively to 27.76?±?6.50° post-operatively, and 28.45?±?6.63° at final follow-up (F?=?57.29, P?<?0.001), and lumbar lordosis (LL) changed from -29.56?±?9.73° pre-operatively to -20.58?±?9.71° post-operatively, and -20.73?±?10.27° at final follow-up (F?=?42.50, P?<?0.001). Mean sagittal vertical axis (SVA) was improved from 11.82?±?4.55 cm pre-operatively to 5.12?±?2.42 cm post-operatively, and 5.03?±?2.29 cm at final follow-up (F?=?79.36, P?<?0.001). No obvious loss of correction occurred, according to the lack of significant differences in the sagittal balance parameters between post-operatively and the final follow-up in all patients (TK: 27.76?±?6.50° vs. 28.45?±?6.63°, TLK: 13.86?±?6.65° vs. 14.42?±?6.7°, LL: -20.58?±?9.71° vs. -20.73?±?10.27°, and SVA: 5.12?±?2.42 cm vs. 5.03?±?2.29 cm, all P?>?0.05, respectively). CONCLUSIONS:The modified posterior wedge osteotomy is an accepted surgical procedure for treating thoracolumbar kyphosis with ALs in AS and results in satisfactory local kyphosis correction, solid fusion, and good clinical outcomes.
Project description:BACKGROUND:Pedicle subtraction osteotomy (PSO) and vertebral column decancellation (VCD) are frequently used methods for correction of thoracolumbar kyphosis resulting from ankylosing spondylitis (AS). However, there are limited reports performed to evaluate the difference of loss of correction and the effectiveness of PSO and VCD techniques in patients with thoracolumbar kyphosis secondary to AS. OBJECTIVE:To retrospectively estimate the effectiveness of correction and loss of correction of PSO and VCD techniques in patients with thoracolumbar kyphosis secondary to AS. METHODS:We performed a retrospective review of 61 consecutive AS kyphosis patients undergoing PSO or VCD surgery from March 2012 to April 2015. The patients were divided into PSO group (n = 25) and VCD group (n = 36) according to the types of osteotomies. Measurement of the radiographic parameters was performed and the change was analyzed. RESULTS:Mean loss of correction in the global kyphosis was 2.31° in the PSO group and 2.29° in VCD group at the last follow-up, respectively, with no significant difference. Progressive junctional kyphosis occurred in both groups. VCD obtained a significantly larger correction than PSO while sharing a similar incidence of complications. No serious complications were observed in the two groups. CONCLUSION:The PSO osteotomy and VCD osteotomy are both safe and effective methods in treating thoracolumbar kyphosis secondary to AS. Mild loss of correction mainly occurred in the global kyphosis in both techniques with no significant difference.
Project description:BackgroundTo investigate the effectiveness and feasibility of a novel vertebral osteotomy technique, transpedicular opening-wedge osteotomy (TOWO) was used to correct rigid thoracolumbar kyphotic deformities in patients with ankylosing spondylitis (AS).MethodsEighteen AS patients underwent TOWO to correct rigid thoracolumbar kyphosis. Radiographic parameters were compared before surgery, 1 week after surgery and at the last follow-up. The SRS-22 questionnaire was given before surgery and at the last follow-up to evaluate clinical improvement. The operating time, estimated blood loss and complications were analyzed.ResultsThe mean operating time and estimated blood loss were 236 min and 595 ml, respectively. The mean preoperative sagittal vertical axis (SVA), thoracic kyphosis (TK), pelvic tilt (PT) and thoracolumbar kyphosis (TLK) were 158.97 mm, 51.24 mm, 43.63 mm and 41.74 mm, respectively, and decreased to 66.72 mm, 35.96 mm, 27.21 mm and 8.67 mm at the last follow-up. The mean preoperative lumbar lordosis (LL) and sacral slope (SS) were 8.30 ± 24.43 mm and 19.67 ± 9.40 mm, respectively, which increased to 38.23 mm and 28.13 mm at the last follow-up. The mean height of the anterior column of osteotomized vertebrae increased significantly from 25.17 mm preoperatively to 37.59 mm at the last follow, but the height of the middle column did not change significantly. SRS-22 scores were improved significantly at the last follow-up compared with preoperatively. Solid bone union was achieved in all patients after 12 months of follow-up, and no screw loosening, screw removal or rod breakage was noticed at the last follow-up.ConclusionsTOWO could achieve satisfactory kyphosis correction by opening the anterior column instead of vertebral body decancellation and posterior column closing, thus simplifying the osteotomy procedure and improving surgical efficacy.
Project description:Pedicle subtraction osteotomy (PSO) is an invasive surgical technique allowing the restoration of a well-balanced sagittal profile, however, the risks of pseudarthrosis and instrumentation breakage are still high. Literature studied primary stability and posterior instrumentation loads, neglecting the load shared by the anterior column, which is fundamental to promote fusion early after surgery. The study aimed at quantifying the load-sharing occurring after PSO procedure across the ventral spinal structures and the posterior instrumentation, as affected by simple bilateral fixation alone, with interbody cages adjacent to PSO level and supplementary accessory rods. Lumbar spine segments were loaded in vitro under flexion-extension, lateral bending, and torsion using an established spine tester. Digital image correlation (DIC) and strain-gauge (SG) analyses measured, respectively, the full-field strain distribution on the ventral surface of the spine and the local strain on posterior primary rods. Ventral strains considerably decreased following PSO and instrumentation, confirming the effectiveness of posterior load-sharing. Supplemental accessory rods considerably reduced the posterior rod strains only with interbody cages, but the ventral strains were unaffected: this indicates that the load transfer across the osteotomy could be promoted, thus explaining the higher fusion rate with decreased rod fracture risk reported in clinical literature.
Project description:ObjectiveJunctional kyphosis is a common complication after corrective long spinal fusion for adult spinal deformity. Whereas there is still a paucity of data on junctional kyphosis, specifically among late posttraumatic thoracolumbar kyphosis (LPTK) patients. Thus, the aim of this study was to investigate the characteristics and risk factors of junctional kyphosis in LPTK patients receiving long segmental instrumented fusion.MethodsWe retrospectively reviewed a cohort of LPTK patients who had received long segmental instrumented fusion (>4 segments) in our center between January 2012 and January 2019. Radiographic assessments included the sagittal alignment, pelvic parameters, bone quality on CT images, and measurements of the cross-sectional area (CSA, cross-sectional area of muscle-vertebral body ratio × 100) and fat saturation fraction (FSF, cross-sectional area of fat-muscle body ratio × 100) of paraspinal muscles. Patients in this study were divided into those with junctional kyphosis or failure (Group J) and those without (Group NJ) during follow-up. Group J included patients with junctional kyphosis (Group JK) and patients with junctional failure (Group JF).ResultsA total of 65 patients (16 males and 49 females, average age 56.5 ± 23.4 years) were enrolled in this study. After (32.7 ± 8.5) months follow-up, 15 patients (23.1%) experienced junctional kyphosis, and four of them deteriorated into junctional failure. Eighty percent (12/15) of junctional kyphosis was identified within 6 months after surgery. In comparison with Group NJ, Group J were older (P = 0.026), longer fusion levels (P < 0.001), greater thoracic kyphosis (P = 0.01), greater global kyphosis (P = 0.023), lower bone quality (P < 0.001), less CSA (P = 0.005) and higher FSF (P <0.001) of paraspinal muscles. Preoperative global kyphosis more than 48.5° (P = 0.001, odds ratio 1.793) and FSF more than 48.4 (P = 0.010, odds ratio 2.916) were identified as independent risk factors of junctional kyphosis. Based on the statistical differences among Group NJ, Group JK and Group JF (P < 0.001), Group JF had lower bone quality than Group NJ (P < 0.001) and Group JK (P = 0.015). In terms of patient-reported outcomes, patients in Group JF had worse outcomes in ODI and VAS scores, and PCS and MCS of SF-36 than Group NJ and group JK CONCLUSION: The prevalence of junctional kyphosis was 23.1% in LPTK patients after long segmental instrumented fusion. Preoperative hyperkyphosis and advanced fatty degeneration of paraspinal muscles were independent risk factors of junctional kyphosis. Patients with lower bone quality were more likely to develop junctional failure.