Failure patterns and related risk factors of sagittal reconstruction following pedicle subtraction osteotomy in patients with ankylosing spondylitis and thoracolumbar kyphosis

OBJECTIVE The aim of this study was to analyze the specific patterns and risk factors of sagittal reconstruction failure in ankylosing spondylitis (AS)–related thoracolumbar kyphosis after pedicle subtraction osteotomy (PSO). METHODS A retrospective study was performed in patients with AS and thoracolumbar kyphosis after lumbar PSO with a minimum follow-up of 2 years. Patients were classified as having successful realignment (group A), inadequate correction immediately postoperatively (group B), and sagittal decompensation during follow-up (group C) according to the immediately postoperative and latest follow-up sagittal vertical axis (SVA). Radiographic parameters and clinical outcomes were collected. Pelvic tilt (PT) was used to assess the magnitude of pelvic backward rotation. Hip structural damage and ossification of the anterior longitudinal ligament (ALL) at the proximal junction, PSO level, and distal junction were also evaluated on radiographs. RESULTS Overall, 109 patients with a mean age of 35.3 years were included. Patients in both group B (n = 16) and group C (n = 13) were older than those in group A (n = 80) (mean ages 43.6 vs 32.9 years, p < 0.011; and 39.2 vs 32.9 years, p = 0.018; respectively). Age (OR 1.102, p = 0.011), and preoperative PT (OR 1.171, p = 0.041) and SVA (OR 1.041, p = 0.016) were identified as independent risk factors of inadequate correction. Additionally, a higher distribution of patients with adequate ALL ossification at the PSO level was found in group B than in group A (37.5% vs 22.5%, p = 0.003). Age (OR 1.101, p = 0.011) and preoperative SVA (OR 1.013, p = 0.020) were identified as independent risk factors of sagittal decompensation. Furthermore, compared with group A, group C showed a higher distribution of patients with severe hip structural damage (15.4% vs 0, p = 0.018) and higher incidences of rod fracture (RF) (38.5% vs 8.8%, p = 0.011) and pseudarthrosis (15.4% vs 0, p = 0.018). Additionally, the incidence of RF (19.6% vs 6.9%, p = 0.045) and changes in the proximal junctional angle (0.5° vs 2.2°, p = 0.027) and the distal junctional angle (0.3° vs 2.2°, p = 0.019) were lower during follow-up in patients with adequate ALL ossification than in those without adequate ossification. CONCLUSIONS Sagittal reconstruction failure in patients with AS could be attributed to inadequate correction immediately after surgery (14.7%) and sagittal decompensation during follow-up (11.9%). Adequate ALL ossification was a risk factor of inadequate correction. However, adequate ALL ossification could decrease the development of RF and relieve the junctional kyphotic change during follow-up. Older age and greater baseline SVA were independent risk factors for both inadequate correction and sagittal decompensation.

Influence of lumbar sagittal profile on pelvic orientation and pelvic motion during postural changes in patients with ankylosing spondylitis–related thoracolumbar kyphosis following pedicle subtraction osteotomy

OBJECTIVE The objective of this study was to investigate the impact of the lumbar sagittal profile on pelvic orientation and pelvic motion during postural changes in patients with ankylosing spondylitis (AS) and thoracolumbar kyphosis and to evaluate the potential risk of prosthetic dislocation after total hip arthroplasty (THA) following pedicle subtraction osteotomy (PSO). METHODS Seventy-two patients with AS-related thoracolumbar kyphosis following spinal osteotomy were retrospectively reviewed, and 21 healthy volunteers were recruited as a control group. Pre- and postoperative 2D full-body images in standing and sitting positions were obtained to evaluate the anterior pelvic plane angle (APPA), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), proximal femur angle (PFA), and femoroacetabular flexion during postural changes. Patients with AS were categorized in either a lordotic or kyphotic group based on the lumbar sagittal profile. RESULTS Significant increases in the SS and decreases in the APPA, PT, and LL were observed postoperatively in both the standing and sitting positions (p < 0.001 for all). Significantly higher APPA, PT, LL, and ΔPT, and lower SS, ΔSS, and ΔSS+ΔPFA were observed in the kyphotic group (p < 0.05). After undergoing PSO, ΔPT and ΔSS significantly decreased while femoroacetabular flexion significantly increased in both AS groups (p < 0.05), and no significant difference was present between the two groups (p > 0.05). Bath Ankylosing Spondylitis Radiology Hip Index scores in the kyphotic group were significantly worse than those in the lordotic group pre- and postoperatively (p < 0.05). No significant difference in parameters concerning pelvic motion (ΔAPPA, ΔPT, and ΔSS) was found when PSO was performed in the thoracolumbar or lumbar spine. CONCLUSIONS Lumbar sagittal profiles greatly affect pelvic orientation and pelvic motion in AS. When THA is performed before PSO, AS patients with lumbar kyphosis are at higher risk of anterior prosthetic dislocation, while those with lordotic lumbar sagittal profiles are at higher risk of posterior dislocation. PSO should be performed prior to THA. After PSO, further decreased pelvic motion indicated a potential risk of posterior prosthetic dislocation after sequential THA, whereas theoretically patients with preoperative lumbar kyphosis are at higher risk of THA dislocation. The site where PSO was performed (thoracolumbar or lumbar spine) does not influence the risk of THA dislocation.

Clinical Effect of Vertebral Column Decancellation Osteotomy Combined with Ponte Osteotomy in Elderly Patients with Old Thoracolumbar Fracture Combined with Kyphosis Deformity

Objective. The purpose of this study was to investigate the clinical effect of vertebral column decancellation (VCD) osteotomy combined with Ponte osteotomy in elderly patients withold thoracolumbar fracture combined with kyphosis deformity.Methods.36 elderly patients with old thoracolumbar fracture combined with kyphosis deformity admitted to our hospital from August 2015 to November 2018 were selected as the study subjects, and all of them were treated with VCDosteotomy combined with Ponte osteotomy.The Cobb angle of thoracolumbar kyphosis, sagittal vertical axis (SVA), visual analog scale (VAS) score.Oswestry disability index (ODI) and life quality were compared at 1 week before and after surgery as well as at the last follow-up. Results. ® All the 36 patients underwent the surgery successfully without serious complications, with the average duration of surgery of (5.13±0.62) h, average blood loss of (821.58±142.67) ml and average hospital stay of (14.02±2.43) d. (2) The Cobb angle of thoracolumbar kyphosis and SVA at 1 week after surgery and at the last follow-up were smaller than those at 1 week before surgery (P < 0.01), but the Cobb angle of thoracolumbar kyphosis and SVA at the last follow-up were slightly larger than those at 1 week after surgery (P < 0.01). (3) The VAS score and ODI score at 1 week after surgery and at the last follow-up were lower than those before surgery (P < 0.01), and the VAS score and ODI score at the last follow-up were lower than those at 1 week after surgery (P < 0.01). @ The scoliosis research society 22-item (SRS-22) score at the last follow-up was higher than that before surgery (P < 0.01). Conclusion. VCD osteotomy combined with Ponte osteotomy in the treatment of old thoracolumbar fracture combined with kyphosis deformity in the elderly can reduce the Cobb angle of thoracolumbar kyphosis, improve sagittal balance, reduce pain symptoms and functional disorders, and improve patents’ life quality, having a good clinical effect.

Radiographic and clinical outcomes of surgical treatment of Kümmell’s disease with thoracolumbar kyphosis: a minimal two-year follow-up

Background Up to now in the surgical treatment of Kümmell’s disease combined with thoracolumbar kyphosis, little research has focused on the evaluation of the imaging and clinical outcomes of restoring the normal alignment and sagittal balance of the spine. This study aimed to evaluate the short to mid-term radiographic and clinical outcomes in the treatment of Kümmell’s disease with thoracolumbar kyphosis. Methods From February 2016 to May 2018, 30 cases of Kümmell’s disease with thoracolumbar kyphosis were divided into group A and B according to whether the kyphosis was combined with neurological deficits. All of the cases underwent surgical treatment to regain the normal spinal alignment and sagittal balance. The radiographic outcomes and clinical outcomes of the cases were retrospectively evaluated. The sagittal imaging parameters including sagittal vertebral axis (SVA),thoracic kyphosis (TK),thoracolumbar kyphosis (TLK),lumbar lordosis (LL),pelvic incidence (PI),pelvic tilt (PT),and sacral slope (SS) before operation,immediately after operation,and the last follow-up of each case were measured and evaluated. The clinical results included the Oswestry Disability Index (ODI) and the Numerical Rating Scale (NRS) of the two groups. Statistical software SPSS21.0 was used to analyze the data. Results In group A: Mean SVA before operation was 75 mm and 26.7 mm at the final postoperative evaluation (P = 0.000); Mean TLK before operation was 39°, and 7.1° at the final postoperative evaluation (P = 0.000); Mean NRS before operation was 4.7, compared with 0.9 at the final postoperative evaluation (P = 0.000). In group B: Mean preoperative SVA was 62.5 mm and decreases to 30.7 mm at the final postoperative evaluation (P = 0.000); Mean TLK before operation was 33°, and 9.7° 2 years post-operation (P = 0.000); Mean NRS prior to surgery was 4.0, and 0.8 at the last follow-up evaluation (P = 0.000). The improvement of the NRS scores of groups A and B was related to the improvement of the cobb angle (P = 0.020); (P = 0.009) respectively. Conclusion In the treatment of Kümmell’s disease with thoracolumbar kyphosis,to restore the normal alignment and sagittal balance can obtain a satisfactory radiographic and clinical short and medium-term effects.

Spinal and Pelvic Alignment of Sitting Posture Associated with Smartphone Use in Adolescents with Low Back Pain

This study aimed to assess the association between smartphone use in the sitting posture and changes in thoracolumbar kyphosis, lumbar lordosis, and pelvic asymmetry in adolescents with low back pain (LBP). Twenty-five adolescents with LBP and 25 healthy adolescents participated in this study. They were instructed to sit on a height-adjustable chair with their hips and knees bent at 90° for 30 min in their usual sitting postures. Thoracolumbar kyphosis, lumbar lordosis, and pelvic asymmetry were measured using a three-dimensional motion capture system. Thoracolumbar kyphosis and lumbar lordosis increased after 30 min of sitting compared to the baseline. In both groups, thoracic kyphosis and lumbar lordosis angle increased with increasing sitting time. Compared to healthy adolescents, adolescents with LBP presented greater thoracolumbar kyphosis and lumbar lordosis after prolonged sitting. Pelvic asymmetry showed no significant difference between the sitting time and groups. Using a smartphone during prolonged sitting may lead to a slumped posture; these associations were more pronounced in adolescents with LBP.

Clinical, radiological, and functional outcomes of posterior-only three-column osteotomy in congenital kyphosis

Aims To describe the clinical, radiological, and functional outcomes in patients with isolated congenital thoracolumbar kyphosis who were treated with three-column osteotomy by posterior-only approach. Methods Hospital records of 27 patients with isolated congenital thoracolumbar kyphosis undergoing surgery at a single centre were retrospectively analyzed. All patients underwent deformity correction which involved a three-column osteotomy by single-stage posterior-only approach. Radiological parameters (local kyphosis angle (KA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic tilt (PT), sacral slope (SS), C7 sagittal vertical axis (C7 SVA), T1 slope, and pelvic incidence minus lumbar lordosis (PI-LL)), functional scores, and clinical details of complications were recorded. Results The mean age of the study population was 13.9 years (SD 6.4). The apex of deformity was in thoracic, thoracolumbar, and lumbar spine in five, 14, and eight patients, respectively. The mean operating time was 178.4 minutes (SD 38.5) and the mean operative blood loss was 701.8 ml (SD 194.4). KA (preoperative mean 70.8° (SD 21.6°) vs final follow-up mean 24.7° (SD 18.9°); p < 0.001) and TK (preoperative mean -1.48° (SD 41.23°) vs final follow-up mean 24.28° (SD 17.29°); p = 0.005) underwent a significant change with surgery. Mean Scoliosis Research Society (SRS-22r) score improved after surgical correction (preoperative mean 3.24 (SD 0.37) vs final follow-up mean 4.28 (SD 0.47); p < 0.001) with maximum improvement in self-image and mental health domains. The overall complication rate was 26%, including two neurological and five non-neurological complications. Permanent neurological deficit was noted in one patient. Conclusion Deformity correction employing three-column osteotomies by a single-stage posterior-only approach is safe and effective in treating isolated congenital thoracolumbar kyphosis. Cite this article: Bone Joint J 2021;103-B(7):1309–1316.