Ankylosing Spondylitis Kyphosis Research Articles

Effectiveness of one-stage posterior eggshell osteotomy and long-segment pedicle screw fixation for ankylosing spondylitis kyphosis combined with acute thoracolumbar vertebral fracture

To explore the safety and effectiveness of one-stage posterior eggshell osteotomy and long-segment pedicle screw fixation in the treatment of ankylosing spondylitis kyphosis combined with acute thoracolumbar vertebral fracture. A clinical data of 20 patients with ankylosing spondylitis kyphosis combined with acute thoracolumbar spine fracture, who were treated with one-stage posterior eggshell osteotomy and long-segment pedicle screw fixation between April 2016 and January 2022, was retrospectively analyzed. Among them, 16 cases were male and 4 cases were female; their ages ranged from 32 to 68 years, with an average of 45.9 years. The causes of injury included 10 cases of sprain, 8 cases of fall, and 2 cases of falling from height. The time from injury to operation ranged from 1 to 12 days, with an average of 7.1 days. The injured segment was T 11 in 2 cases, T 12 in 2 cases, L 1 in 6 cases, and L 2 in 10 cases. X-ray film and CT showed that the patients had characteristic imaging manifestations of ankylosing spondylitis, and the fracture lines were involved in the anterior, middle, and posterior columns and accompanied by different degrees of kyphosis and vertebral compression; and MRI showed that 12 patients had different degrees of nerve injuries. The operation time, intraoperative bleeding, intra- and post-operative complications were recorded. The visual analogue scale (VAS) score and Oswestry disability index (ODI) were used to evaluate the low back pain and quality of life, and the American spinal cord injury association (ASIA) classification was used to evaluate the neurological function. X-ray films were taken, and local Cobb angle (LCA) and sagittal vertical axis (SVA) were measured to evaluate the correction of the kyphosis. All operations were successfully completed and the operation time ranged from 127 to 254 minutes (mean, 176.3 minutes). The amount of intraoperative bleeding ranged from 400 to 950 mL (mean, 722.5 mL). One case of dural sac tear occurred during operation, and no cerebrospinal fluid leakage occurred after repair, and the rest of the patients did not suffer from neurological and vascular injuries, cerebrospinal fluid leakage, and other related complications during operation. All incisions healed by first intention without infection or fat liquefaction. All patients were followed up 8-16 months (mean, 12.5 months). The VAS score, ODI, LCA, and SVA at 3 days after operation and last follow-up significantly improved when compared with those before operation ( P<0.05), and the difference between 3 days after operation and last follow-up was not significant ( P>0.05). The ASIA grading of neurological function at last follow-up also significantly improved when compared with that before operation ( P<0.05), including 17 cases of grade E and 3 cases of grade D. At last follow-up, all bone grafts achieved bone fusion, and no complications such as loosening, breaking of internal fixation, and pseudoarthrosis occurred. One-stage posterior eggshell osteotomy and long-segment pedicle screw fixation is an effective surgical procedure for ankylosing spondylitis kyphosis combined with acute thoracolumbar vertebral fracture. It can significantly relieve patients' clinical symptoms and to some extent, alleviate the local kyphotic deformity.

A case report on digital preoperative design, clinical application and finite element analysis for a patient with ankylosing spondylitis kyphosis.

Objective: By assessing a case of ankylosing spondylitis (AS) after thoracic lumbar protrusion deformity in a digital model and verifying its effectiveness after surgery for orthopaedic surgery process simulation, a finite element model was established for biomechanical experiments. Method: A 56-year-old patient with AS underwent preoperative thoracic lumbar spine computed tomography. The data were reconstructed using MIMICS16.0 software and modelled to design and measure the nailing parameters. A three-dimensional model was established using ANSYS14.0 software, and the actual surgical procedure was simulated using biomechanical experiments. The model was verified by comparing the X-ray films obtained from patients during preoperative forward bending, stretching and lateral flexion, with the model further tested using the Hueter-Volkmann principle. Result: On comparing the measurements across three different load cases (forward bending, after stretching and lateral flexion) in patients with AS after thoracic lumbar protrusion deformity and the original X-ray images, no difference was found between the model of deformation and real patient movement displacement across the vertebral body. On simulating the stress distribution, the measured T10-L4 vertebral body stress values at every point in the injured vertebrae were, on the whole, directed at both the upper and lower ends and exhibited a decreasing trend, and the stress distribution gradually decreased from the injured vertebrae (T12 and L1) to the upper and lower ends. Conclusion: The accuracy of the research model is high, the geometric similarity is good and relevant applied anatomy can be undertaken using the model parameter measurement. This study provides a successful example of the application of digital technology in the field of spinal deformity and a novel idea for the treatment of AS-related kyphosis.

UPDATE ON SURGICAL TREATMENT OF CERVICAL KYPHOSIS IN ANKYLOSING SPONDYLITIS

Cervical kyphosis in ankylosing spondylitis is a debilitating disease for the patient as well as a complex deformity for the surgeon to treat. Ankylosing spondylitis patients should be assessed clinically and radiologically to determine their indications for surgery. Thorough preoperative evaluation of the patient and surgical planning are critical to the success of the corrective surgery. Various kyphotic deformities and osteotomy classifications can be taken into consideration for surgical planning. There are various types of corrective procedures for the treatment of cervical kyphosis. For patients with ankylosing spondylitis and chin-on-chest deformity, pedicle subtraction osteotomy offers the largest angle of correction. However, pedicle subtraction osteotomy is highly technically demanding and associated with a substantial risk for neurovascular complications.

Application of vertebral body compression osteotomy in pedicle subtraction osteotomy on ankylosing spondylitis kyphosis: Finite element analysis and retrospective study.

Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease, with pathological characteristics of bone erosion, inflammation of attachment point, and bone ankylosis. Due to the ossified intervertebral disc and ligament, pedicle subtraction osteotomy (PSO) is one of the mainstream surgeries of AS-related thoracolumbar kyphosis, but the large amount of blood loss and high risk of instrumental instability limit its clinical application. The purpose of our study is to propose a new transpedicular vertebral body compression osteotomy (VBCO) in PSO to reduce blood loss and improve stability. A retrospective analysis was performed on patients with AS-related thoracolumbar kyphosis who underwent one-level PSO in our hospital from February 2009 to May 2019.A total of 31 patients were included in this study; 6 received VBCO and 25 received eggshell vertebral body osteotomy. We collected demographic data containing gender and age at diagnosis. Surgical data contained operation time, estimated blood loss (EBL), and complications. Radiographic data contained pre-operative and follow-up sagittal parameters including chin brow-vertical angle (CBVA), global kyphosis (GK), thoracic kyphosis (TK), and lumbar lordosis (LL). A typical case with L2-PSO was used to establish a finite element model. The mechanical characteristics of the internal fixation device, vertebral body, and osteotomy plane of the two osteotomy models were analyzed under different working conditions. The VBCO could provide comparable restoring of CBVA, GK, TK, and LL in the eggshell osteotomy procedure (all p > 0.05). The VBCO significantly reduced EBL compared to those with eggshell osteotomy [800.0ml (500.0-1,439.5 ml) vs. 1,455.5 ml (1,410.5-1,497.8 ml), p = 0.033]. Compared with the eggshell osteotomy, VBCO showed better mechanical property. For the intra-pedicular screw fixation, the VBCO group had a more average distributed and lower stress condition on both nails and connecting rod. VBCO had a flattened osteotomy plane than the pitted osteotomy plane of the eggshell group, showing a lower and more average distributed maximum stress and displacement of osteotomy plane. In our study, we introduced VBCO as an improved method in PSO, with advantages in reducing blood loss and providing greater stability. Further investigation should focus on clinical research and biomechanical analysis for the application of VBCO.

Are Both Preoperative Full-Spine 3Dimensional Computed Tomography Scans and X-Ray Films Necessary for Patients with Ankylosing Spondylitis Kyphosis?

ObjectiveThis study is aimed to investigate whether both pre‐operative full‐spine 3Dimensional computed tomography scan (3D CT) and X‐ray film were necessary for patients with severe ankylosing spondylitis (AS) kyphosis deformity.MethodsThe research objects were selected from the inpatients with AS in our hospital from 2017 to 2019. A total of 42 patients were included in the study. On both the synthesized 2Dimensional (2D) lateral radiograph and X‐ray film, the globe kyphosis (GK), the lumber lordosis (LL), the thoracolumbar kyphosis (TLK) and the thoracic kyphosis (TK) were measured. And the angle seventh thoracic vertebra (T7), the angle twelfth thoracic vertebra (T12) and the angle third lumber vertebra (L3) were also measured. Two researchers with professional medical education were randomly selected to perform the measurement method and record the measurement data. Two researchers independently completed, recorded, and evaluated the accuracy and consistency of the measurement data. This study used intraclass correlation coefficient (ICC) to analyze the synthesized 2D lateral radiograph and general X‐ray film of 42 subjects by two researchers, in order to evaluate the consistency of data measurement results between the examiners. Through the comparison of the above parameters that the GK, LL, TLK, TK, angle T7, angle T12 and angle L3, the evaluation was made both pre‐operative full‐spine 3D CT and X‐ray film were necessary for patients with severe AS kyphosis deformity.ResultsThere was no significant difference between the GK, LL, TLK, TK, angle T7, angle T12, angle L3 on the synthesized 2D lateral radiograph and that on X‐ray film (P = 0.240, 0.324, 0.199, 0.095, 0.421, 0.087, 0.478). Agreement two researchers was excellent with ICC of the GK, LL, TLK, TK, angle T7, angle T12, angle L3 (0.977, 0.969, 0.986, 0.945, 0.947, 0.915, 0.857) on the synthesized 2D lateral radiograph. The Bland–Altman plot results that the measurement results of examiners are reliable and stable.ConclusionBy estimating the degree of spinal sagittal imbalance and measuring the Cobb angle, we can see that full‐length spine radiographs of the patients are unnecessary for patients with severe AS kyphosis deformity who will or have undergone preoperative spine 3D CT.

Clinical Results of Utilizing the Satellite Rod Technique in Treating Ankylosing Spondylitis Kyphosis

ObjectiveAccording 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.MethodsPatients 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.ResultsThe 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.ConclusionThe satellite rod technique is also recommended for patients who undergo PSO osteotomy to correct ankylosing spondylitis kyphosis deformities.

Anterior Pelvic Plane: A Potentially Useful Pelvic Anatomical Reference Plane in Assessing the Patients' Ideal Pelvic Parameters Without the Influence of Spinal Sagittal Deformity.

Study Design:Observational study.Objective:This study was aimed at investigating the reliability of anterior pelvic plane (APP) as an anatomical reference plane for assessing the patients’ pelvic incidence in patients with ankylosing spondylitis kyphosis deformity.Methods:The globe kyphosis (GK), lumber lordosis (LL), thoracolumbar kyphosis (TLK), thoracic kyphosis (TK), anatomical cervical 7 sacrum angle (aC7SA), and cervical 7 sacrum angle (C7SA) were measured on full-length spine radiography imagines. The pelvic incidence (PI), anatomical pelvic tilt (aPT), and anatomical sacral slope (aSS) were measured on the pelvic synthesized 2D lateral radiography imagines. Because the angle between APP and vertical line was about 4°, Angle1 and tPT were calculated using the following formulas: Angle1 = aC7SA − 4; PT = aPT + 4. According to the study conducted by Vialle, traditional PT (tPT) was calculated using the following widely accepted formula: tPT = PI * 0.37 − 7. Measured PT (mPT) was also measured on the full-length spine radiography imagines.Results:The data analysis showed that PI, mPT, aSS, aPT, and APPA were 50.83 ± 13.44°, 32.52 ± 4.64°, 41.36 ± 9.46°, 8.56 ± 6.80°, and 23.95 ± 5.17°, respectively. There was no significant difference between the PT and tPT (12.56 ± 6.80, 11.49 ± 4.73; P = .152). So, the results demonstrated that the PT could play the equivalent effect as tPT did for making surgical plans in patients with kyphosis deformity.Conclusion:The pelvic anatomical reference plane had potential to be used in assessing the patients’ ideal pelvic incident without the influence of spinal sagittal deformity. The aPT+4 may represent patients’ postoperative ideal PT.

Improvement of Sleep Quality in Patients With Ankylosing Spondylitis Kyphosis After Corrective Surgery

A retrospective study. The aim of this study is to investigate the changes in sleep quality in patients surgically treated for kyphosis due to ankylosing spondylitis (AS) and the correlation between these changes and spinal sagittal realignment. Sleep problems are prevalent in AS patients. However, little attention has been paid to the sleep quality in patients with AS kyphosis and the effect of surgical intervention on sleep quality. We have retrospectively reviewed 62 patients with AS-induced thoracolumbar kyphosis who underwent surgically treatment from October 2012 to November 2016. Sleep quality was evaluated by the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Preoperative and postoperative radiological characteristics and supine function were documented. We compared the above-mentioned parameters pre- and 24 months postoperatively and analyzed the correlation of the changes in the PSQI with the changes in radiological characteristics. Fifity-one patients (82%) classified as poor sleepers preoperatively. In addition to use of sleeping medication, each domain of the PSQI and the total PSQI were increased postoperatively. Improved sleep quality was correlated with changes in spinal sagittal characteristics, among which the lumbar lordosis (LL) and the chin-brow vertical angle (CBVA) were the independent correlation factors. The number of patients with supine dysfunction decreased from 89% to 15% after surgery. Significant differences were identified in the PSQI scores between the patients with and without supine dysfunction either pre- or postoperatively. Surgical correction of spinal deformity may improve sleep quality and supine function in patients with AS. Spinal sagittal realignment may be correlated with the improvement of sleep quality. 4.

Clinical results and surgery tactics of spinal osteotomy for ankylosing spondylitis kyphosis: experience of 428 patients

ObjectiveTo report the clinical results and surgical tactics of spinal osteotomy for ankylosing spondylitis (AS) kyphosis based on the experiences of 428 patients.MethodsFrom January 2003 to January 2015, a total of 428 patients suffering from AS kyphosis who underwent a one- or two-level pedicle subtraction osteotomy (PSO) or vertebral column decancellation (VCD) osteotomy in our hospital were reviewed. Pre- and postoperative radiological parameters and the chin-brow vertical angle (CBVA) were measured. Intraoperative, postoperative, and general complications were recorded.ResultsAll patients could walk with horizontal vision and lie on their backs postoperatively. The pre- and postoperative average global kyphosis (GK) angles were corrected from 82.6 to 12.7° (p = 0.000) in the two-level group and from 55.8 to 9.6° (p = 0.000) in the one-level group, respectively. The mean sagittal vertical axis (SVA) improved from 29.4 to 8 cm (p = 0.000) in the two-level group and from 18.0 to 4.3 cm (p = 0.000) in the one-level group. The CBVA improved from 68.3 to 8.2° (p = 0.000) in the two-level group and from 46.2 to 4.2° (p = 0.000) in the one-level group. Although no major acute complications such as death or complete paralysis occurred, the complication rate was 6.5% in the one-level group and 23.6% in the two-level group.ConclusionSpinal osteotomy, such as PSO and VCD, can improve the quality of life of AS patients as well as correct kyphotic deformities. The one-level spinal osteotomy showed a lower complication rate, while two-level spinal osteotomy was a relatively aggressive procedure that was more suitable in correcting severe AS kyphotic deformities.

Short-term efficacy of pedicle subtraction osteotomy plus long segment fixation for kyphosis in ankylosing spondylitis combined with thoracolumbar fractures

Objective To evaluate the efficacy of pedicle subtraction osteotomy (PSO) plus long-segment pedicle nail bar system in treating kyphosis in ankylosing spondylitis (AS) combined with thoracolumbar fractures. Methods A retrospective case series study was made on the clinical data of 13 patients with kyphosis in AS combined with thoracolumbar fractures admitted to Xiaoshan Hospital of Traditional Chinese Medicine from January 2012 to May 2016. There were 11 males and two females, aged 32-64 years [(44.3±10.6)years]. Two fractures occurred at T11, five at T12, three at L1, and three at L2. According to the American Spinal Injury Association (ASIA) classification, the spinal injuries were rated as grade B in one patient, grade C in four, grade D in five and grade E in three. All patients underwent PSO plus long-segment pedicle nail bar system. The operation duration, intraoperative blood loss, fixation segments, and complications were recorded. Thoracolumbar kyphosis angle (TL) and sagittal vertical axis (SVA) were measured to evalute the correction effect. Visual analogue scale (VAS), Oswestry disability index (ODI), ASIA grade were compared before and after operation to assess the efficacy. Results All patients were followed up for 12-18 months [(15.2±1.2)months]. The operation time ranged from 120 to 256 minutes [(175.2±40.3)minutes]. The intraoperative blood loss ranged from 660 to 3 300 ml [(1 011±681)ml]. Number of fixed seqments was 12-16 (12.2±0.8). Anemia occurred in one patient after operation, and the patient recovered after blood transfusion. Incision infection occurred in one patient after operation, which was improved after antibiotic treatment through osmotic culture. Compared with the detection before operation, postoperative TL was improved significantly [(52.6±6.2)° vs. (17.1±3.1)°], with an average correction rate of 67.5%; final follow-up showed decreased VAS [(7.5±0.7)points vs. (1.9±0.6)points] and decreased ODI [(75.2±5.3)points vs. (22.9±4.4)points] (P<0.05); SVA was improved significantly [(11.5±2.1)cm vs. (3.5±0.9)cm], with an average correction rate of 69.6% (P<0.05). ASIA grade was significantly improved at the final follow-up, including grade D in three patients and grade E in ten patients (P<0.05). There was no case of epidural hematoma or infection after operation, and no loosening of internal fixator or pseudarthrosis formation occurred during follow-up. Conclusion For kyphosis in AS combined with thoracolumbar fractures, PSO osteotomy plus long segment pedicle nail bar system treatment can significantly reduce lower back pain and promote functional recovery. Key words: Spondylitis, ankylosing; Spinal fractures; Kyphosis; Osteotomy

Proposal of a New Treatment-Oriented Classification System for Spinal Deformity in Ankylosing Spondylitis

ObjectiveTo describe and apply an optimal classification system for the management of ankylosing spondylitis (AS) that may be appropriate to make a preoperative surgical plan. BackgroundThe treatment choices of ankylosing spondylitis kyphosis remain controversial. The lack of a widely accepted classification system contributes to the variation in surgical decision making. MethodsThe classification is mainly based on radiographic findings. The sagittal deformity of spine in ankylosing spondylitis is classified according to three criteria: the location of the apex, the lumbar modifier (A, lumbar lordosis <0°, and B, lumbar kyphosis >0°) and the thoracic/thoracolumbar kyphosis severity modifier (− or +). ResultsThe ankylosing spondylitis kyphosis can be divided into 4 types according to the location of the apex: Type I (lumbar), Type II (thoracolumbar), Type III (thoracic), Type IV (cervical or cervicothoracic junction). Either Type II or Type III is further divided into four subtypes based on the lumbar modifier and the thoracic/thoracolumbar kyphosis severity modifier: Type IIA−, Type IIA+, Type IIB−, Type IIB+, Type IIIA−, Type IIIA+, Type IIIB−, and Type IIIB+. Surgical decision making for AS kyphosis can be made according to the new classification. ConclusionThis new classification system can be used effectively to classify AS kyphosis, which can be used to guide surgical decision making, including determining the site and the levels of osteotomies. Further research may be needed to validate the classification.

Two-Level Osteotomy for Correcting Severe Ankylosing Spondylitis Kyphosis: Radiologic Outcomes of Different Osteotomy Position-Selection Strategy for Different Type of Patients

ObjectiveTo report on the radiologic outcomes of different osteotomy position–selection strategies for a two-level osteotomy for correcting severe ankylosing spondylitis kyphosis. MethodsFrom July 2009 to September 2016, a total of 46 patients in our department with severe ankylosing spondylitis kyphosis who underwent two-level pedicle subtraction osteotomy (PSO) were studied. Pre- and postoperative relevant parameters were recorded. The patients were divided into two types and further separated into four groups. The lumbar lordotic angle of Type I patients was larger than or equal to 0°. The lumbar lordotic angle of Type II patients was less than 0°. The patients of Group I belonging to Type I underwent superior spinal osteotomy at the L1 vertebra. The patients of Group II belonging to Type I underwent superior spinal osteotomy at the T12 vertebra. The patients of Group III belonging to Type II underwent superior spinal osteotomy at the L1 vertebra. The patients of Group IV belonging to Type II underwent superior spinal osteotomy at the T12 vertebra. ResultsAnalysis of preoperative data showed that the lumbar lordosis (LL) of Group I and II patients was significantly larger than those of Group III and IV. Postoperative data analysis showed that there was significant difference among the four groups in the postoperative LL and TK. The LL of Group II and III patients was smaller than that of Group I patients, and was larger than that of Group IV patients. Group II and Group III patients had more moderate LL and better physiological curvature than those in Group I and Group IV. There were no significant differences between Group II and Group III patients in postoperative LL, thoracolumbar kyphosis, thoracic kyphosis, and global kyphosis. And, likewise, there were no significant differences among the four groups in cervical 7 sacrum angle (C7SA). ConclusionTwo-level osteotomy was effective for correcting severe ankylosing spondylitis kyphosis. In patients with LL greater than or equal to 0°, it would be better if the second or superior spinal osteotomy was performed at T12 rather than at L1 for restoring the sagittal balance. In patients with LL smaller than 0°, it would be more satisfactory to perform two-level osteotomy at lumbar vertebras for correcting sagittal imbalance. Level of EvidenceLevel III.

Ankylosing spondylitis kyphosis surgical correction postoperative evaluation via SRS-22 domain investigation

BackgroundThe SRS-22 is used to evaluate clinical outcomes in ankylosing spondylitis kyphosis patients. This study aimed to investigate the relationship between Scoliosis Research Society-22 (SRS-22) domains and satisfaction with management in patients who underwent surgical correction for ankylosing spondylitis kyphosis. The relationship between patient satisfaction and SRS-22 domain scores will feedback abundant information of therapeutic effect and significance for treatment guidance.MethodsIn this work, 106 patients with ankylosing spondylitis kyphosis at a single institution, who underwent posterior spinal fusion of five levels or more to the sacrum, completed SRS-22 evaluation preoperatively and followed up for a minimum of 2-year postoperation. Wilcoxon tests were performed to compare preoperative with 2-year postoperative scores. Spearman correlations were investigated to evaluate associations between the 2-year treatment satisfaction and therapeutic effect in SRS-22 domain scores.ResultsThere were 12 females and 94 males with mean BMI of 16.4 kg/m2 and at the mean age of 46.3 years. All of the primary surgeries were treatments performed with mean follow-up of 26 months. A statistical improvement between paired pre- and 2-year postoperative SRS-22 domain scores and most radiographical parameters, commonly P ≤ 0.05, was designed and implemented. The majority of patients gave SRS-22 satisfaction score with 3.0 or more (88.5%) or 4.0 or more (68.8%), which are consistent with the moderate ceiling effect. Spearman coefficient correlations between the SRS-22 domain scores and patient satisfaction were all statistically significant, and they were from low to strong: [Mental (0.30), Activity (0.71), Pain (0.25), and Appearance (0.40)]. Furthermore, correlations for all radiographical and operative parameters were from low to strong.ConclusionSRS-22 Activity domain correlates strongest with patient satisfaction in ankylosing spondylitis kyphosis patients who have undergone surgical correction at 2-year follow-up.

The Safe Correction Angle of Osteotomy at T12 and L1 for Ankylosing Spondylitis Kyphosis: Patients With 2-level Osteotomy.

This is a retrospective clinical study. To investigate the correction angle and safety of the spinal osteotomy at the T12 or L1 vertebra. Monosegment subtraction osteotomy cannot effectively correct severe kyphosis in ankylosing spondylitis (AS), generally 2-level spinal osteotomy was taken for achieving expected correction. According to literature, the T12 or L1 were usually taken as the upper spinal osteotomy vertebra. Because of the canalis vertebralis at the T12 and L1 were spinal cord and medullary cone, so the spinal osteotomy at the T12 or L1 vertebra were more dangerous than at lower level. The correction angle and safety of the spinal osteotomy at the T12 or L1 vertebra have not yet been reported. From July 2009 to 2014, 33 patients in our department with severe AS kyphosis underwent 2-level pedicle subtraction osteotomy were studied. Preoperative and postoperative relevant parameters and complications were recorded. The upper spinal osteotomy was taken at the T12 vertebra for 10 patients. The upper spinal osteotomy was taken at the L1 vertebra for 23 patients. The mean amount of correction of T12 and L1 was 26.230 and 27.952 degrees, respectively. All patients could walk with orthophoria and lie horizontally postoperatively. No deadly vascular and neurological lesion occurred. Performing pedicle subtraction osteotomy at T12 and L1 can safely achieve a mean correction of 26.230 and 27.952 degrees, respectively. Two-level osteotomy was safely and advocated for correcting severe AS kyphosis. Level III.

Establishment of a three-dimensional finite element model of ankylosing spondylitis kyphosis

Establishment of a three-dimensional finite element model of ankylosing spondylitis kyphosis

Surgical strategies for cervical spine fracture combined with ankylosing spondylitis and cervicothoracic junction kyphosis

Objective To discuss the operative strategies for cervical spine fracture combined with ankylosing spondylitis and the deformity of cervicothoracic kyphosis. Methods Retrospectively analyzed 21 cases of cervical spine fracture combined with ankylosing spondylitis and the deformity of cervicothoracic kyphosis, who underwent surgeries from January, 2007 to August, 2014. Twenty males and 1 female were included. Mean age was (48.6±7.5) years (range, 36-65 years). The preoperative American Spine Injury Association (ASIA) classification distribution: 2 cases of Grade A, 6 cases of Grade B, 7 cases of Grade C, 5 cases of Grade D, and 1 case of of Grade E. The investigative surgical methods including posterior cervical open reduction, internal fixation and bone graft fusion; posterior cervical open reduction/decompression, internal fixation and bone graft fusion; or combined posterior and anterior cervical decompression, bone graft fusion and instrumentation. The operative time and blood loss were recorded, the clinical therapeutic effect was evaluated by visual analogue scale (VAS) score, ASIA grade improvement, cervical curvature (the angle between a line drawn parallel to the inferior endplate of C2 and a line drawn parallel to the inferior endplate of C7 in the lateral plane of an X-ray image) and radiological assessment (including bone graft fusion condition and internal fixation position). Results One case died from severe pulmonary infection and respiratory failure at the 45th day after operation. All the other 20 patients obtained complete follow-up with a mean time of (39.4±8.76) months (range, 25-59 months). 7 cases received posterior cervical open reduction, internal fixation and bone graft fusion, average operative time was (92.1±5.4) minutes and average blood loss was (96.1+23.7) ml. 9 cases received the posterior cervical open reduction and decompression, internal fixation and bone graft fusion, mean operation time was (121.4±14.0) minutes and blood loss was (250.0±38.9) ml. 3 cases experienced combined posterior and anterior cervical decompression, bone graft fusion and fixation, average operative time was (222.4±14.9) minutes and average blood loss was (354.3+46.7) ml. Mean of VAS scores at the 3th month postoperatively was 2.76±0.46, significantly lower than the preoperatively VAS scores (8.95±0.36). Mean of VAS scores at the 24th month postoperatively was 1.77±0.39, significantly lower than those at the 3th month postoperatively. The neurological function of spinal cord achieved significant improvement after operations and continued recovered gradually in the subsequent follow up. ASIA Classification distribution at the 24th month postoperatively was: 0 case of Grade A, 0 case of Grade B, 3 cases of Grade C, 8 cases of Grade D, 9 case of Grade E. Mean of the cervical curvature after operation was -7.1°±1.9°, significantly higher than preoperatively(-13.4°±3.3°) and did not have any loss of Cobb's angles at 24th month after operation. All the surviving cases achieved solid bone graft fusion. Mean bone graft fusion time was 5.8 months (range, 4-9 months). There was no internal fixation loose, fracture and dislocation occurred during follow up. Conclusion All procedures can significantly relieve the painful symptoms, effectively restore the normal cervical alignment and stability, and remarkably improve the neural function of the patients suffering cervical spine fracture combined with ankylosing spondylitis and the deformity of cervicothoracic junction kyphosis. Key words: Spondylitis, ankylosing; Cervical vertebrae; Spinal fractures; Thoracic vertebrae; Kyphosis

Analysis of curative effect of kyphosis cancellous ossification osteotomy for ankylosing spondylitis

Objective To investigate the efficacy to cancellous ossification of spinal osteotomy for the treatment of ankylosing spondylitis kyphosis deformity and. Methods 34 patients with ankylosing spondylitis kyphosis in our Department from Jan 2014 January to Fab 2016 were selected and randomly divided into the observation group and the control group, the observation group used to cancellous ossification of spinal osteotomy combined with pedicle screw internal fixation for the treatment, control group using spinal wedge osteotomy combined with pedicle screw internal fixation for the treatment of bleeding, and deformity correction the extent of operation time, operation measure and comparison of two kinds of operation, and postoperative complications. Results In the observation group, the kyphotic angle of the thoracic vertebra was corrected from (37.4±10.0) ° to (1.8±0.5) °and then to (1.9±0.9) °, laparoscopic angle was corrected from (-13.7±17.3)° to (27.0±7.2) ° and then to (27.3±6.8) °, the sagittal plane balance was calculated from preoperative (35.8±10.6) ° to (12.7±4.2) ° andthen to (12.9±4.4) °, the maxillary angle was corrected from (63.5±11.1) ° to (12.8±3.1) °and then to (12.6±3.6)° at the second week and the third month, respectively, there was no significant difference compared with the control group (P= 0.077). While the sixth month after the end of follow-up, the difference was statistically significant (P=0.035); In the observation group, the fusion rate of bone graft was 100.0% higher than that of the control group (83.4%) (P=0.007). The observation group of spine function also had a significant difference in the follow-up period Higher than the control group (P=0.041). Conclusion The spine to cancellous ossification osteotomy used in ankylosing spondylitis kyphosis has good curative effect, can effectively restore the spinal height, prevent orthopedic excessive or loss, improve the fusion rate of bone graft, is worth the clinical promotion. Key words: To cancellous ossification; Osteotomy; Ankylosing spondylitis; Kyphosis

The Precise Bending Rod Technique: A Novel Method for Precise Correction of Ankylosing Spondylitis Kyphosis.

To report a new technique. To introduce a new method of precise correction controlling for ankylosing spondylitis kyphosis. The exact angle method is excellent for calculating the pedicle subtraction osteotomy angle but is difficult to perform during surgery. In this study, the precise rod bending technique was proposed as a new method for precise correction controlling for ankylosing spondylitis kyphosis through illustrative cases. A preoperative plan using the exact angle method, with exact osteotomy angle and level determined, was prepared using a whole-spine lateral x-ray film. Then a precise contoured rod imitating the predicted spine correction was obtained using the lateral spine x-ray film that was of the actual size of the trunk. This rod model was disinfected and used for precisely controlling kyphosis correction in ankylosing spondylitis patients with good cervical spine and hip joints. Four ankylosing spondylitis kyphosis patients were successfully corrected using the precise bending rod technique. Their mean age was 31 years, the mean operative time was 247 minutes (160-320 min), the mean volume of bleeding was 1482 mL (727-2700 mL), and the average follow-up period was 13.8 months (9-17 mo). All patients regained their sagittal balance (all C7-SSVL≤2 cm). The predicted ostetomy degree was accurate to within 2 degrees compared with the achieved degree at the osteotomy site. No complications occurred during or after surgery. The precise rod bending technique is a simple, effective method for precise correction of kyphosis caused by ankylosing spondylitis. The surgical result corresponded to the preoperative planning.

Changes of the abdomen in patients with ankylosing spondylitis kyphosis.

A retrospective clinical study. To investigate changes of the abdomen in patients with ankylosing spondylitis kyphosis. Since 1945, many authors had reported the good clinical and radiographical outcomes and higher patient satisfaction rates of spinal osteotomy techniques. However, to our knowledge, whether the visceral and diaphragmatic compression that results from the inferior edge of the thoracic cage is relieved by the surgery has not yet been reported. From July 2010 to July 2013, 26 patients (24 males, and 2 females) with severe ankylosing spondylitis kyphosis, who underwent pedicle subtraction osteotomy in the Department of Orthopaedics at Chinese People's Liberation Army General Hospital were studied. Preoperative and postoperative computed tomographic scan, 3-dimensional reconstruction, and preoperative pulmonary function test were performed. Via those tests, the minimum distance on the median sagittal plane of the abdomen (MD), the acreage of the abdominal median sagittal plane (AMSPA), the diaphragm angle on median sagittal plane can be gained. A paired sample t test was performed to determine the differences between the preoperative and postoperative AMSPA and MD and diaphragm angle on median sagittal plane, respectively. Postoperative MD/preoperative MD and postoperative AMSPA/preoperative AMSPA and global kyphosis were also analyzed by performing independent sample t test for the 2 groups. The diaphragm angle on median sagittal plane has changed significantly in all the patients. There was significant change of both MD and AMSPA in patients whose abdominal wall was folded into abdomen, whereas neither MD nor AMSPA in patients without the factor. To a certain degree, the diaphragmatic compression and the visceral compression could be compensated for by turning to flattening or even developing into kyphosis of the lumbar lordosis before surgery, which could be corrected by a spinal osteotomy. Sagittal rotation of diaphragm in ankylosing spondylitis kyphosis could also be improved by a spinal osteotomy.

Radiologic and clinical outcomes comparison between single- and two-level pedicle subtraction osteotomies in correcting ankylosing spondylitis kyphosis

Background contextSingle pedicle subtraction osteotomy (PSO) has been used to correct ankylosing spondylitis (AS) kyphosis successfully, but this approach seems insufficient to correct severe kyphosis. Two-level PSO has been attempted to correct advanced kyphosis in recent years. However, studies have not yet compared outcomes between single and double PSOs, and the indications to perform two-level PSO are unclear. PurposeThis study aimed to compare the radiologic and clinical outcomes between single- and two-level PSOs in correcting AS kyphosis. Study designThis work is a retrospective cohort study. Patient sampleSixty patients were included. Thirty-seven underwent single-level PSO, and 23 underwent one stage two-level PSO. Outcome measuresThe radiologic analysis included thoracic kyphosis, thoracolumbar junction, lumbar lordosis, pelvic index, chin-brow vertical angle (CBVA), sagittal vertical axis (SVA), and pelvic tilt (PT). Clinical assessment was performed with a Scoliosis Research Society-22 (SRS-22) outcomes instrument. The operative time, blood loss, and complications were also documented. MethodsAll of the aforementioned measurements were recorded before surgery, after surgery, and at the last follow-up. The outcomes were compared between the two groups. ResultsThe operating time was 232±52 minutes for single- and 282±43 minutes for two-level PSOs. The blood loss was 1,240±542 mL (Level 1) and 2,202±737 mL (Level 2). The total spine correction was 43.2°±15.1° (Level 1) and 60.6°±19.1° (Level 2) (p<.001), the SVA correction was 13.2±10.6 cm (Level 1) and 23.6±10.2 cm (Level 2) (p<.001), and the PT correction was 10.1°±11.6° (Level 1) and 15.2°±10.8° (Level 2) (p<.001). The CBVA correction was 50.6°±17.8° (Level 1) and 51.4°±18.6° in (Level 2) (p>.05). All patients could walk with horizontal vision and lie on their backs postoperatively. The SRS-22 improved from 1.7±0.4 to 4.2±0.8 in the two-level group and 1.8±0.8 to 4.3±0.7 in the single-level group. The fusion of the osteotomy was achieved in each patient. The complications were similar in both groups. ConclusionsPedicle subtraction osteotomy is an effective method to correct kyphosis with AS. Most patients can be successfully treated by single PSO. In severe patients, two-level PSO may be preferable because its correction ability is greater and spine curvature is better than that of single-level PSO. However, two-level PSO requires an increased operating time and results in increased blood loss. Nevertheless, the complications were similar between the two groups.