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Background
Defining the postoperative pelvic tilt (PT) individually can help to reconstruct sagittal balance. However, the postoperative actual PT is hardly restored to theoretical value. Some cases with theoretical postoperative PT was overcorrected and still did not have normal horizontal visual field after surgery. The objective of this study is...
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Study design:
A retrospective study.
Purpose:
To investigate the incidence of iliac screw loosening with a two-rod vs. multi-rod construct and the effect on clinical and radiographic outcomes after surgery for adult spinal deformity (ASD).
Overview of literature:
Multi-rod construct is useful for preventing rod fracture in ASD surgery. However...
Background
Patients with severe kyphotic deformity (Cobb > 100°) secondary to ankylosing spondylitis (AS) occasionally cannot undergo corrective surgery in the prone position. Osteotomy in the lateral position might provide a possible solution. In this study, we aim to evaluate the clinical efficacy and safety of staged osteotomy in the lateral pos...
To construct and validate prediction formulae of sagittal alignment in thoracolumbar kyphosis secondary to ankylosing spondylitis (AS) after osteotomy. A total of 115 AS patients who suffered from thoracolumbar kyphosis and underwent osteotomy were enrolled, with 85 patients in derivation group and 30 patients in validation group. Radiographic para...
Background:
Corrective osteotomy is an effective surgery for correcting posture in patients with ankylosing spondylitis (AS). Despite satisfactory correction, some patients experience re-stooping during follow-up. However, there have been no studies on re-stooping in AS. We aimed to analyze the factors that affect re-stooping.
Methods:
Fifty pat...
Citations
... Previous research indicated that the PT and CL could be partially corrected after thoracolumbar osteotomy, 28,29 aligning with our findings in group C but conflicting with the results in groups A and B. Similarly, while a significant improvement of TPA was obtained by 3-level PSO at the final follow-up, identical result was not found in groups A and B. PI-LL was significantly improved in all of the 3 groups, and the ΔPI-LL of group C was significantly larger than that of groups A and B. Such outcomes were probably due to the higher severity of deformity in group C comparing to the other 2 groups. Additionally, the better correction achieved by multilevel PSO might be more beneficial for the compensation of cervical and pelvic parameters, which facilitates better sagittal spinal reconstruction for the patients with AS-related kyphosis. ...
Objective:
To compare the clinical outcomes and biomechanical characteristics of one-, two-, and three-level PSO, and establish selection criteria based on preoperative radiographic parameters.
Methods:
Patients undergone PSO to treat AS from February 2009 to May 2019 in our hospital were enrolled. According to the quantity of osteotomy performed, the participants were divided into Group A (one-level PSO, n= 24), Group B (two-level PSO, n= 19), and Group C (three-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.
Results:
Three-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 one-level PSO. Larger stress of screws and vertebra was observed at the distal end in the model simulating three-level PSO.
Conclusion:
Multi-level 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 GK > 85.95°, TPA > 62.3°, SVA > 299.55mm, and PT+CBVA > 109.6°.
... 23 Since the restricted magnitude of deformity correction achieved by 1-level PSO, ideal spinopelvic sagittal alignment might not be achieved in the most AS patients with thoracolumbar kyphosis. 24 Except for the significant decrease in PT in the AS patients with less baseline SVA or C7 tilt, compensated pelvic backward rotation remained to maintain the sagittal balance (C7 tilt ¼ 0) after PSO. 24,25 Thus, more caudal PSO level would mainly result in the restoration of SVA. ...
... 24 Except for the significant decrease in PT in the AS patients with less baseline SVA or C7 tilt, compensated pelvic backward rotation remained to maintain the sagittal balance (C7 tilt ¼ 0) after PSO. 24,25 Thus, more caudal PSO level would mainly result in the restoration of SVA. The greater decrease in PT or AA might not occur in AS patients following PSO with more caudal osteotomy level (Figures 3, 4). ...
Study Design
Retrospective study.
Objectives
To analyze the change in acetabular anteversion (AA) after lumbar pedicle subtraction osteotomy (PSO) in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis who have already undergone total hip arthroplasty (THA).
Methods
AS patients with thoracolumbar kyphosis following lumbar PSO from January 2005 to January 2020 were retrospectively reviewed. Only the patients performed with THA prior to the PSO were included. AA was measured on the full-length standing posterior-anterior radiographs using the ellipse method.
Results
Twenty patients (34 hips) with a mean age of 36.8 years (range, 22 to 63 years) were included. After lumbar PSO, AA was reduced from 18.59° to 5.85° ( P < 0.001). Postoperative change in AA was correlated with the spinal deformity correction. Additionally, the change in AA postoperatively was correlated with pelvic incidence (PI) (R = 0.346, P = 0.045). Although the postoperative change in sagittal vertical axis (SVA) was larger in the patients after L2 or L3 PSO (153.97 mm vs 70.03 mm, P = 0.006), no difference was found in the postoperative change in AA (12.83° vs 10.96°, P = 0.540) compared with the patients following L1 PSO.
Conclusions
AA was significantly decreased following lumbar PSO and the postoperative change in AA was correlated with the magnitude of spinal deformity correction. Notably, the effect of osteotomy level on the postoperative change in AA was limited in the AS patients underwent 1-level PSO.
Background
This study aimed to determine preoperative predictors for sagittal imbalance in kyphosis secondary to ankylosing spondylitis (AS) after one-level three-column osteotomy.
Methods
A total of 55 patients with AS who underwent one-level three-column osteotomy were enrolled. The patients were divided into two groups according to sagittal vertical axis (SVA) value at the final follow-up (group A: SVA > 5 cm; group B: SVA ≤ 5 cm). The radiographic measures included global kyphosis, lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), sacral slope, T1 pelvic angle (TPA), SVA, osteotomized vertebral angle and PI and LL mismatch (PI − LL). Postoperative clinical outcomes were evaluated using Scoliosis Research Society-22 questionnaire (SRS-22) and Oswestry Disability Index (ODI).
Results
Fifty-five AS patients had an average follow-up of 30.6 ± 10.2 months (range 24–84 months). Group A had larger preoperative and postoperative LL, PT, PI − LL, TPA and SVA values compared with group B ( P < 0.05), and no significant differences were found in ODI and SRS-22 scores between the two groups ( P > 0.05). Preoperative LL, PT, PI − LL, TPA, and SVA values were positively correlated with the follow-up SVA value ( P < 0.05). Among them, TPA > 40.9°, PI − LL > 32.5° and SVA > 13.7 cm were the top three predictors with the best accuracy to predict sagittal imbalance. Immediate postoperative SVA value of ≤ 7.4 cm was a key factor in reducing the risk of sagittal imbalance during follow-up.
Conclusions
Preoperative TPA > 40.9°, PI − LL > 32.5° and SVA > 13.7 cm could predict sagittal imbalance in AS kyphosis after one-level three-column osteotomy, and additional osteotomies were recommended for this condition. Immediate postoperative SVA ≤ 7.4 cm was an optimal indicator for preventing sagittal imbalance.
Level of evidence
IV.
:
The proper diagnosis and treatment of patients with concurrent hip and spine pathological processes can be challenging because of the substantial overlap in symptomatology.
➤:
There is no consensus on which pathological condition should be addressed first.
➤:
Factors such as advanced spinal degeneration, deformity, and prior fusion alter the biomechanics of the spinopelvic unit. Attention should be paid to recognizing these issues during the work-up for a total hip arthroplasty as they can result in an increased risk of dislocation.
➤:
In patients with concurrent spine and hip degeneration, the surgeon must pay close attention to appropriate implant positioning and have consideration for implants with enhanced stability to minimize the risk of dislocation.
➤:
A proper understanding of sagittal balance and restoration of this balance is integral to improving patient outcomes following spinal surgery.
➤:
The advent of new imaging modalities, increased awareness of spinopelvic mobility, as well as a better understanding of sagittal alignment will hopefully improve our treatment of patients with hip-spine syndrome.
Introduction/objectives:
This study was to investigate the role of pelvic incidence (PI) in the development of Andersson lesions (ALs) in ankylosing spondylitis (AS) patients with kyphosis and to evaluate the difference in sagittal spinopelvic parameters between inflammatory ALs and mechanical ALs.
Method:
A total of 135 AS patients with kyphosis were reviewed. The patients were classified into AL group and non-AL group based on the presence or absence of ALs. Additionally, AS patients with ALs were also classified as either inflammatory or mechanical lesions depending on the radiological features of the lesions. The sagittal spinopelvic parameters of all these AS patients were measured and compared. Logistic regression analysis was performed to determine the powerful variables for predicting ALs in AS patients.
Results:
ALs were detected in 34 patients (25.2%) of the total 135 AS patients. The mean PI of the AL group was 40.0°, which was significantly lower than that (48.3°) of the non-AL group (P < 0.001). No statistically significant difference was observed in PI (P = 0.350) between the inflammatory lesion group and the mechanical lesion group. Logistic regression analysis showed that only PI was a statistically significant risk factor for ALs (P < 0.001) and was negatively correlated with ALs (odds ratio = 0.76).
Conclusions:
These data suggest that low PI is closely associated with ALs in AS patients with kyphosis and that it might be a possible risk factor for the development of ALs. Moreover, both inflammatory and mechanical ALs patients had similarly low PI.Key Points• Low PI was closely associated with ALs in AS patients with kyphosis and might be a possible risk factor for development of ALs.• Either inflammatory or mechanical ALs patients had similar low PI.
