OBJECTIVE: To evaluate different patterns of coronal deformity secondary to ankylosing spondylitis (AS), to propose relevant treatment strategies, and to assess efficacy of asymmetrical pedicle subtraction osteotomy (APSO).
METHODS: Coronal deformity was defined as coronal Cobb angle over 20º or coronal balance distance (CBD) more than 3 cm. 65 consecutive AS patients with concomitant coronal and sagittal deformity who underwent PSO were included. The average follow-up time was 40.4 months. Radiographic evaluation included coronal Cobb angle and CBD. Furthermore, sagittal parameters were used to assess magnitude and maintenance of kyphosis correction.
RESULTS: Based on curve characteristics, coronal deformity caused by AS included four different radiologic patterns: Pattern I: lumbar scoliosis; Pattern II: C-shaped thoracolumbar curve; Pattern III: trunk shift without major curve; Pattern IV: proximal thoracic scoliosis. APSO was performed for patients in Pattern I to III while conventional PSO was applied for patients in Pattern IV. Significant improvement in all the sagittal parameters were noted in 65 patients without obvious correction loss at the last follow-up. Besides, significant and sustained correction of coronal mal-alignment was identified in 59 APSO-treated patients. Rod fracture occurred in four cases and revision surgery was performed for one case.
CONCLUSIONS: According to radiologic manifestations, coronal deformity caused by AS could be categorized into four patterns. APSO proved to be a feasible and effective procedure for correction of Pattern I to III patients. Coronal deformity pattern, apex location, sagittal profile of lumbar spine and preoperative hip function should be considered for osteotomy level selection in APSO.

暂无摘要。

OBJECTIVE: The surgical treatment of patients with ankylosing spondylitis and severe thoracolumbar kyphosis combined with hip flexion contracture is very difficult for all the surgeons. The femoral neck osteotomy (FNO) is the first step to break the ice. The evaluation of a new modified FNO method is very important to improve the curative effect.
METHODS: Five male patients with nine bone-fused hips who underwent the new femoral neck osteotomy were included from October 2021 to March 2022. The FNO was designed that the saw blade was manipulated from the lateral femoral neck base to the inferior part of the femoral head, keeping Pauwels\' angle less than 30° on the coronal plane. On the transverse plane, the angle between the saw blade and the coronal plane was more than 15°. On the sagittal plane, the saw blade cut through the femoral neck. They accepted pedicle subtraction osteotomy (PSO) after FNO according to the patient\' recovery. Then, 2 weeks later, the patients underwent total hip arthroplasty (THA). The visual analogue scale (VAS), Harris hip score (HHS) and passive hip flexion-extension range of motion (ROM) were used to evaluate hip function. The data were analyzed by paired t-test.
RESULTS: The average operation time and blood loss of FNO, the average interval between FNO and THA were collected. The average angle of the trunk and lower limb (ATL) was 36.33° ± 16.36° pre-FNO, 82.89° ± 13.51° post-FNO and 175.22° ± 3.42° post-THA. The average VAS scores were 0 pre-FNO, 5 ± 1.58 post-FNO and 2.6 ± 0.55 post-THA. The average HHS was 43.56 ± 1.59 preoperatively and 83.89 ± 2.21 postoperatively. The average hip extension ROM was 23.89° ± 12.69° pre-FNO, -22.67° ± 14.18° post-FNO and - 3.33° ± 2.50 post-THA°. The average hip flexion ROM was 23.89° ± 12.69° pre-FNO, 35.56° ± 12.11° post-FNO and 104.44° ± 5.27° post-THA. The differences among them were significant (p < 0.05). Only one hip (11.11%) displaced completely after FNO.
CONCLUSIONS: A new modified FNO was developed, which can provide osteotomy with a certain degree of stability and greater ease for performing PSO and THA.

To investigate the influence of pelvic incidence (PI) on the kyphosis curve patterns and clinical outcomes in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis and to construct a classification of AS according to the PI value for surgical decision-making. 107 AS patients underwent single-level lumbar pedicle subtraction osteotomy (PSO) and finished a minimal of 2-year follow-up. All patients were divided into three groups: low PI (PI ≤ 40°), moderate PI (40° < PI ≤ 60°), and high PI (PI > 60°). Standing lateral radiographs were taken to evaluate the location of kyphotic apex, thoracic kyphosis (TK), lumbar lordosis (LL), C7 sagittal vertical axis (SVA), spino-sacral angle (SSA), global kyphosis (GK), PI, sacral slope (SS), and pelvic tilt (PT). Visual Analogue Scale (VAS) score, Oswestry Disability Index (ODI) and Bath Ankylosing Spondylitis Functional Index (BASFI) were used to evaluate quality of life. Before surgery, a significant difference was shown in the average LL and the mean GK in high PI group was the largest among the three groups. Correction of SVA, GK and LL in high PI group was the smallest among the three group. No significant difference in clinical outcomes was found among the three groups before surgery and at the final follow-up. Regarding the preoperative sagittal profile, the kyphosis curve pattern of moderate PI group is similar to that of low PI group. For AS patients in these two groups, harmonious sagittal alignment can be restored by a single-level PSO. However, the sagittal imbalance is insufficiently realigned by a single-level PSO in a patient with high PI.

The goal in this study was to compare the efficacy and safety outcomes of vertebral column decancellation (VCD) and pedicle subtraction osteotomy (PSO) for patients with ankylosing spondylitis (AS) with thoracolumbar kyphotic deformity.
This study was registered on the International Prospective Register of Systematic Reviews (PROSPERO). The authors conducted a computer search of PubMed, EMBASE, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wan Fang Database, and Wei Pu Database to collect controlled clinical studies on the efficacy and safety of VCD and PSO for patients with AS with thoracolumbar kyphotic deformity. The search covered the period from database establishment to March 2023. Two researchers screened the literature, extracted data, and evaluated the risk of bias of the included studies; these researchers recorded the authors and the sample size, and they extracted data on the intraoperative blood loss, Oswestry Disability Index, spine sagittal parameters, operation time, and complications in each study. Meta-analysis was performed using RevMan 5.4 software provided by Cochrane Library.
A total of 6 cohort studies with a total of 342 patients were included in this study, including 172 patients in the VCD group and 170 patients in the PSO group. The VCD group had lower intraoperative blood loss than the PSO group (mean difference [MD] -274.92, 95% CI -506.63 to -43.20, p = 0.02); significant correction of the sagittal vertical axis compared with the PSO group (MD 7.32, 95% CI -1.24 to 15.87, p = 0.03), and the operation time was shorter than that of the PSO group (MD -80.28, 95% CI -150.07 to -10.48, p = 0.02).
This systematic review and meta-analysis showed that VCD had more advantages than PSO in correcting the sagittal imbalance in the treatment of AS with thoracolumbar kyphotic deformity, and VCD had less intraoperative blood loss, shorter operation time, and satisfactory results in improving the quality of life.

OBJECTIVE: The commonly used treatments of adult degeneration scoliosis (ADS) were posterior long segment screw fixation with osteotomies. Recently, lateral lumbar intervertebral fusion combined two-stage posterior screw fixation (LLIF + PSF) as a new strategy without osteotomy. Herein, this study aimed to compare the clinical and radiological outcomes among LLIF + PSF and pedicle subtraction osteotomy (PSO), posterior column osteotomies (PCO).
METHODS: Totals of 139 ADS patients underwent operation with 2 years longer follow-up visit between January 2013 and January 2018 in Ningbo No.6 Hospital were enrolled into this study. 58 patients were included in PSO group, 45 in PCO group and 36 in LLIF + PSF group, The clinical and radiological data were reviewed from medical records. Baseline characteristic, perioperative radiological data (sagittal vertical axis (SVA), coronal balance (CB), Cobb angle of Mian curve (MC), Lumbar lordosis (LL), pelvic tilt (PT) and pelvic incidence-lumbar lordosis mismatch (PI-LL)), clinical outcomes (VAS of back and leg, Oswestry disability index (ODI) and Scoliosis Research Society 22-question Questionnaire (SRS-22)) and complications were evaluated and compared.
RESULTS: There were no significantly difference in baseline characteristics, preoperative radiological parameters and clinical outcomes among three groups. LLIF + PSF group was significantly shorter in operation time than other two groups (P < 0.05), whereas significant longer hospital stay was observed in LLIF + PSF group (P < 0.05). As for radiological parameters, LLIF + PSF group had significantly improvement in SVA, CB, MC, LL and PI-LL (P < 0.05). Moreover, LLIF + PSF group achieved significantly less correction loss in SVA, CB and PT than PSO and PCO group (1.5 ± 0.7 VS 2.0 ± 0.9 VS 2.2 ± 0.8, P < 0.05; 1.0 ± 0.4 VS 1.3 ± 0.5 VS 1.1 ± 0.7, P < 0.05 and 4.2 ± 2.8 VS 7.2 ± 3.1 VS 6.0 ± 2.8, P < 0.05). Significantly recovery in VAS of back and leg, ODI score and SRS-22 were found among all groups, however, LLIF + PSF shown significant better clinical therapy maintain at follow-up visit than other two groups (P < 0.05). There were no significantly difference in complications among groups (P = 0.66).
CONCLUSIONS: Lateral lumbar interbody fusion combined two-stage posterior screw fixation (LLIF + PSF) can achieve comparable clinical therapy for adult degeneration scoliosis as osteotomy strategies. However, furthermore more studies need be taken for verifying the effect of LLIF + PSF in the future.

To determine the clinical- and surgical-related factors of hip joint structural changes in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis who underwent PSO.
Hip involvement was assessed by the Bath Ankylosing Spondylitis Radiology Hip Index (BASRI-h) and defined by a score of at least 2. 52 patients with BASRI-h scores maintained and 78 patients with BASRI-h scores increased during follow-up were retrospectively reviewed. Clinical data were recorded. Radiological assessment was performed preoperatively, postoperatively, and at the final follow-up.
No significant difference existed in age, gender and follow-up time between the groups, but earlier onset of AS, longer disease and kyphotic duration, and worse Bath Ankylosing Spondylitis Functional Index (BASFI) scores at the final follow-up were observed in patients with BASRI-h scores increased (P < 0.05). Besides, global kyphosis (GK), T1-pelvic angle (TPA), pelvic tilt (PT) and anterior pelvic plane angle (APPA) were always larger in patients with BASRI-h scores increased, accompanied with more sacral fixation (P < 0.05). Multivariate logistics regression showed that earlier onset of AS, longer kyphotic duration, larger preoperative GK, sacral fixation and larger APPA during follow-up were independent risk factors.
Earlier onset of AS and longer kyphotic duration were the clinical risk factors of hip joint structural changes in AS patients following PSO, while larger preoperative GK, sacral fixation in PSO and larger APPA during follow-up were the surgical-related factors. Surgeons should inform patients with risk factors of the possibility for severe hip joint structural changes after PSO.

OBJECTIVE: According to the literature, there are no clinical reports documenting the use of the satellite rod technique in the treatment of ankylosing spondylitis kyphosis. The purpose of this retrospective study was to compare the clinical outcome of patients with ankylosing spondylitis kyphosis who adopted satellite rods versus those who did not.
METHODS: Patients with ankylosing spondylitis kyphosis who underwent one or two-level pedicle subtraction osteotomy (PSO) were reviewed, and total of 119 patients (112 males and seven females, average age 39.89 ± 6.61 years) were eligible and included in this present study. Anterior-posterior and lateral full-length spine X-ray films were performed preoperatively and at the two-year follow-up visit. Global kyphosis (GK), lumbar lordosis (LL), thoracolumbar kyphosis (TLK), thoracic kyphosis (TK), and osteotomy angle (OA) were measured. The complications of every group of patients were collected. Pre- and postoperative health-related quality of life instruments, including the Bath Ankylosing Spondylitis Functional Index (Basfi) and Scoliosis Research Society outcomes instrument-22 (SRS-22), were recorded. The patients were divided into three groups based on features of their osteotomy including PSO levels and whether the satellite rod technique was applied. Patients who underwent one-level PSO without the satellite rod technique were categorized in the one-level group. Patients who underwent one-level PSO with the satellite rod technique were classified in the satellite rod group. Patients who underwent two-level PSO without the satellite rod technique were included in the two-level group. The paired sample t test was used to compare pre- and postoperative parameters. One-way ANOVA was performed for multiple group comparisons.
RESULTS: The average follow-up time is 29.31 ± 3.66 months. The patients\' GK were significantly improved from 46.84 ± 20.37 degree to 3.31 ± 15.09 degree. OS achieved through each osteotomy segment of one-level group (39.78 ± 12.29 degree) and satellite rods group (42.23 ± 9.82 degree), was larger than that of two-level group (34.73 ± 7.54 and 28.85 ± 7.26 degree). There was no significant difference between the one-level group and the satellite rod group in achieving the OS. Thirteen patients experienced different complications (10.92%). Three patients experienced rod fracture in the one-level group. There was no rod fracture or screw failure in the satellite rod group or the two-level group.
CONCLUSIONS: The satellite rod technique is also recommended for patients who undergo PSO osteotomy to correct ankylosing spondylitis kyphosis deformities.

OBJECTIVE: To evaluate the sagittal parameters and clinical outcome of pedicle subtraction osteotomy (PSO) for the treatment of ankylosing spondylitis (AS) combined with thoracolumbar kyphosis.
METHODS: The clinical data of 38 patients with AS combined with thoracolumbar kyphosis who underwent PSO were enrolled and divided into the lumbar lordosis group and the lumbar kyphosis group according to the preoperative sagittal morphology. They were subdivided into the lumbar lordosis T12 group, lordosis L1 group, kyphosis L2 group, and kyphosis L3 group. The spine sagittal parameters were compared between the preoperative and the postoperative. Outcome evaluation was performed by the Japanese Orthopedic Association (JOA) score, visual analogue scale (VAS), and the Oswestry Disability Index (ODI).
RESULTS: A total of 38 patients with AS combined with thoracolumbar kyphosis were successfully treated by PSO, with a mean follow-up time of 26.9 ± 11.9 months. There were 30 males and 8 females with a mean age of 41.6 ± 7.1 years. Twenty patients consisted in the lumbar lordosis group and 18 patients in the lumbar kyphosis group. GK, SVA, and CBVA were improved significantly (P < 0.05) at the final follow-up between the lumbar lordosis T12 group and the L1 group. Patients in the lumbar kyphosis L2 group and L3 group all received satisfactory, including LL, GK, and SVA (P < 0.05). There was no statistically significant difference in the preoperative TK, GK, SVA, PT, and PI between the lumbar lordosis and lumbar kyphosis groups (P > 0.05). Postoperative complications occurred in three cases.
CONCLUSIONS: PSO was a practical method for the treatment of patients with AS combined with thoracolumbar kyphosis. PSO at L3 was recommended to be selected for the lumbar kyphosis to obtain greater SVA correction. CBVA of single-segment PSO may be significantly lower than the two-segment PSO in the management of patients with kyphosis of lower CBVA.

OBJECTIVE: To describe spinal osteotomy in lateral position, which might be a new strategy for correcting thoracolumbar kyphotic deformity combined with severe hip flexion contracture, and to present two cases in which this method was successfully performed.
METHODS: Spinal osteotomies in lateral position were performed in two patients with severe thoracolumbar kyphosis combined with hip flexion contracture, which was not suitable for operation in the prone position. Case 1: a 33-year-old female AS patient still had severe hip flexion contracture due to poor rehabilitation after total hip replacement (THR). The range of movement of the hip was only about 15° in right and 10° in left. Pre-operativethoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), and sagittal vertical axis (SVA) were 52.4°, 49.1°, 42.7°, and 315 mm, respectively. Pedicle subtraction osteotomy (PSO) at L3 was performed in the lateral position. The eggshell procedure was used during osteotomy. Case 2: a 45-year-old male AS patient presented coexisting rigid thoracolumbar kyphosis and hip flexion contracture. The range of movement of the hip was only about 20° in right and 25° in left. Pre-operativeTK, TLK, LL and SVA were 34.9°, 66.8°, 58.8° and 290.8 mm, respectively. PSO at L2 was performed in lateral position. The eggshell procedure was also used.
RESULTS: Sagittal malalignments of both patients were greatly improved. For case 1, the total operation time was 5.5 h. The blood loss was 1500 mL and the amount of allogeneic blood transfusion was 1580 mL during the operation. SVA was reduced to 127 mm and LL decreased from preoperative 42.7° to -28.4°. The correction angle through L3 was 34.7° and the correction angle through the osteotomy segment was 62.9°. For case 2, the duration of surgery was 6.5 h. The operative blood loss was 2000 mL and the total amount of blood transfusion was 2020 mL. SVA was reduced to 209.8 mm and LL decreased from preoperative 58.8° to 9.2°.The correction angle through L2 was 37.1° and the correction angle through the osteotomy segment was 55°. No intra-operative or post-operative complications were observed. Six months after PSO, case 1 had good posture for standing and sitting. The case 2 underwent bilateral THRs nine months after PSO.
CONCLUSIONS: PSO could be performed in the lateral position successfully. For AS patients who cannot be placed in the prone position due to coexisting severe thoracolumbar kyphosis and hip flexion contracture, performing spinal osteotomy in the lateral position as the first step is an alternative.