Pulmonary function improvement in patients with ankylosing spondylitis kyphosis after pedicle subtraction osteotomy

Spinal deformity correction in ankylosing spondylitis

Background:

Ankylosing spondylitis (AS) is a complex, debilitating disease with few available medical therapies in its later stages.

Methods:

We reviewed current clinical approaches for caring for AS patients with an emphasis on the risks and outcomes associated with surgical intervention.

Results:

It is critical to understand the natural history and surgical outcomes of patient with AS. Surgery is not without risks, as a vertebral body osteotomy is often required to re-establish spinopelvic equilibrium. However, surgery can lead to clinical improvements in pain, disability, cardiac function, respiration, digestion, and sexual activity.

Conclusion:

Deformity correction for AS should be carefully considered in symptomatic patients.

Research hotspots and trends analysis of ankylosing spondylitis: a bibliometric and scientometric analysis from 2009 to 2018

Background

This study utilized bibliometric analysis to qualitatively and quantitatively analyze hotspots and predict trends in the field of ankylosing spondylitis (AS) research.

Methods

Articles about AS were obtained from the Web of Science Core Collection and PubMed database, and bibliometric analysis was carried out through CiteSpace and the Online Analysis Platform of Literature Metrology and Bibliographic Item Co-Occurrence Matrix Builder (BICOMB). Then, co-word biclustering analysis was conducted to obtain research hotspots and predict trends using gCLUTO software.

Results

A total of 6,818 articles on AS from 2009 to 2018 were analyzed, showing an increasing publication trend (558 articles in 2009 to 851 articles in 2018). The Journal of Rheumatology was the leading journal in AS research, with an impact factor (IF) of 3.634 and H-index value of 49. In terms of region, the United States led the world in this field, and The University of Toronto was the leading institution for AS research. Van Der Heijde, D was the most prolific author in the field. Eight research hotspots in the field of AS were also identified.

Conclusions

Our analysis identified eight research hotspots, and predicted that surgical treatment and etiology will be the main AS research trends in the future. This study provides new directions and ideas for future research in AS.

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

STUDY DESIGN

A retrospective study.

OBJECTIVE

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.

SUMMARY OF BACKGROUND DATA

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

LEVEL OF EVIDENCE

4.

Systemic changes associated with quality of life after surgical treatment of kyphotic deformity in patients with ankylosing spondylitis: a systematic review

PURPOSE

In addition to changes in the skeletal system after spinal osteotomy for treatment of kyphotic deformity in advanced-stage AS patients, many other systemic changes associated with the patients' quality of life were reported. The purpose of this study was to conduct a systemic review of the literature to determine systemic changes associated with patients' quality of life following correction of kyphotic deformity secondary to ankylosing spondylitis.

METHODS

We searched the databases PubMed, EMBASE, Clinicalkey and Cochrane Library without time restriction. Selected papers were assessed by published guidelines. We investigated systemic changes associated with patients' quality of life after surgical treatment of advanced ankylosing spondylitis.

RESULTS

The initial search yielded 888 citations. Twelve of these studies met the inclusion and exclusion criteria. Two were level II evidence study, and ten were level III evidence studies. Changes were reported including aorta length, abdominal morphology, digestive function, cardiopulmonary function, psychological status, and sexual activity.

CONCLUSIONS

In addition to skeletal changes after spinal osteotomy for treatment of kyphotic deformity in advanced-stage AS patients, many other changes were reported. Spine surgeons should pay more attention to these life quality-related changes and be aware of potential risks when performing surgery for advanced-stage AS patients. These slides can be retrieved under Electronic Supplementary Material.

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

OBJECTIVE

To report the clinical results and surgical tactics of spinal osteotomy for ankylosing spondylitis (AS) kyphosis based on the experiences of 428 patients.

METHODS

From 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.

RESULTS

All 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.

CONCLUSION

Spinal 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.

Correlation between diaphragmatic sagittal rotation and pulmonary dysfunction in patients with ankylosing spondylitis accompanied by kyphosis

OBJECTIVE

This study was performed to investigate the correlation between pulmonary dysfunction patterns and diaphragmatic sagittal rotation in patients with ankylosing spondylitis accompanied by kyphosis.

METHODS

Thirty patients (27 male, 3 female) with kyphotic deformity secondary to ankylosing spondylitis underwent pedicle subtraction osteotomy and were retrospectively reviewed. All patients had undergone preoperative computed tomography with three-dimensional reconstruction, full-length spine radiographs, and pulmonary function tests. The diaphragmatic angle in the median sagittal plane (DA), pulmonary function test results, and radiological parameters were studied.

RESULTS

Correlation coefficients were used to present the correlation between the DA and pulmonary function and the global kyphosis (GK), respectively. The data analysis presented positive correlations between the DA value and vital capacity (VC), forced vital capacity (FVC), expiratory reserve volume (ERV), inspiratory reserve volume (IRV) and peak expiratory flow (PEF). There was likewise a negative correlation between DA value and the global kyphosis (GK). Additionally, there were further significantly statistical improvements for DA, ERV, IRV, FVC, and VC, PEF, postoperatively.

CONCLUSIONS

Except for the restriction of the chest wall motion and the abnormalities of lung parenchyma, the diaphragmatic sagittal rotation is also an influencing factor of pulmonary dysfunction in patients with ankylosing spondylitis accompanied by kyphosis.

Radiological morphology variances of osteotomized vertebra-disc complex following pedicle subtraction osteotomy for ankylosing spondylitis with thoracolumbar kyphosis: the incidence, mechanisms, and prognosis

BACKGROUND CONTEXT

Inaccurate osteotomy cut along with incomplete or even subluxated bone-on-bone closure of osteotomy gap following pedicle subtraction osteotomy (PSO) may be disastrous, hampering the lordosing effect and increasing the likelihood of complications. The inelastic yet osteoporotic spine in ankylosing spondylitis (AS) is specially predisposed to such suboptimal osteotomy, while the relevant data concerning this issue are scarce.

PURPOSE

This study aimed to analyze the incidence of radiological morphology variances (RMV) of osteotomized vertebra-disc complex (OVDC) following PSO in patients with kyphotic AS, conceptualize the mechanisms of the deviated morphology, and investigate the prognosis.

STUDY DESIGN

This is a retrospective radiological data analysis.

PATIENT SAMPLE

The sample being screened comprises 71 patients with thoracolumbar kyphotic AS who underwent single-level PSO at our hospital between March 2006 and February 2014. They were stratified by the presence of bridging syndesmophytes (BS) locating within the OVDC.

OUTCOME MEASURES

Any irregular radiological configuration of OVDC other than the wedge morphology would be considered as RMV and were studied with care to fully describe and classify the spectrum of deviated morphologic features. Multiple spinopelvic sagittal parameters were measured to assess both the regional lordosing effect and the global realignment of sagittal spinal profile.

METHODS

For each selected patient with confirmed RMV, the radiological morphology was assessed, defined, and categorized. The prognosis involving surgical corrections and maintenance of spinopelvic sagittal parameters, as well as the remodeling in disordered osteotomized vertebral shape over time, were also investigated.

RESULTS

The incidence of RMV was 21.9% in positive BS group (PG) and 30.8% in negative BS group (NG). Inappropriate angle and range of osteotomy accounted for the largest share (1 pts for PG and 10 pts for NG, 57.9%) of mechanisms responsible for RMV, followed by vertebral subluxation (VS) (5 pts for PG and 2 pts for NG, 36.8%) and failed osteotomy gap closure (1 pts for PG, 5.3%). For these patients, the mean bony lordosing effect per PSO segment was 36.0°±8.9° postoperatively, and decreased to 34.7°±8.7° by a mean follow-up of 3 years (p=.076). The magnitude of neighboring disc opening was significantly higher in NG (10.2°±6.5° vs. 2.4°±3.2°, p=.009). The global kyphosis and sagittal vertical axis were significantly corrected (77.0°±21.2° vs. 24.4°±18.8°; 160.6°±72.4° vs. 48.2°±38.6 mm, all p<.001) and remained stable by the ultimate follow-up (p>.05). No devastating neurologic deficits were noticed. Patients with VS and failed osteotomy gap closure exclusively showed solid bone healing and adaptive remodeling without rod breakage at final follow-up.

CONCLUSIONS

Radiological morphology variances of OVDC were a high occurrence following PSO in AS, being mainly attributed to inaccurate osteotomy cut and VS. Neighboring disc opening and rotational or translational subluxation were major available remedial mechanisms strengthening the lordosing effect when that of vertebral wedging was impaired and insufficient. The bone fusion and remodeling concerning the subluxated or dislocated osteotomized vertebra was utterly favorable, maintaining the kyphosis correction and preventing instrumentation failure.

Pedicle Subtraction Osteotomy with a Cage Prevents Sagittal Translation in the Correction of Kyphosis in Ankylosing Spondylitis

BACKGROUND

Sagittal translation (ST) is an accidental event that surgeons commonly encounter during a spinal osteotomy in the correction of kyphosis in ankylosing spondylitis (AS). However, there is a paucity of effective techniques to prevent ST. The purpose of this study was to propose a pedicle subtraction osteotomy (PSO) with a cage as a method to prevent ST and to explore the efficacy and feasibility of this method in the treatment of kyphosis in AS.

METHODS

We retrospectively reviewed 89 consecutive patients with AS kyphosis who underwent a PSO (Group B, 46 patients) or a PSO with a cage (Group A, 43 patients) from February 2009 to December 2013. Pre- and post-operative radiographic results were reviewed. ST and complications were analyzed in both groups. Clinical assessment was performed using the Scoliosis Research Society-22 (SRS-22) outcomes metric. The patients were followed up for at least 2 years.

RESULTS

Group A achieved the same re-alignment of the kyphotic spine as Group B. Two (4.7%) of the 43 patients in Group A and 14 (30.4%) of the 46 patients in Group B had intraoperative ST (χ2 = 10.020, P = 0.002). Significant differences were identified between the two groups in the height change of the osteotomized column. SRS-22 scores improved significantly in both groups. Seven patients experienced neurologic complications (1 in Group A and 6 in Group B). Eight patients had cerebrospinal fluid leakage (2 in Group A and 6 in Group B).

CONCLUSION

PSO with a cage significantly avoided ST during the osteotomy procedure and might represent a new, safe, and feasible choice for treating patients with AS kyphosis.

Osteotomies in ankylosing spondylitis: where, how many, and how much?

INTRODUCTION

This article presents the current concepts of correction of spinal deformity in ankylosing spondylitis (AS) patients. Untreated AS can be a debilitating disease. In a few patients, disease progression results in severe spinal deformity affecting not only the thoracolumbar, but also the cervical spine. Surgery for correction in AS patients has a long history. With the advent of modern instrumentation, standardization of surgical and anesthesiologic techniques, surgical safety and corrective results could be improved and experiences from lumbar osteotomies could be transferred to the cervical spine.

METHODS

This article presents the current concepts of correction of spinal deformity in AS patients. In particular, questions regarding the localization and number of osteotomies, the optimal surgical target angle as well as planning and prediction of postoperative alignment are discussed.

RESULTS

Insight into recent technical developments, current challenges with correction and geometric analysis of center of rotation (COR) in cervical 3-column osteotomies (3CO) will be presented.

CONCLUSION

The article should encourage readers to improve surgical correction efficacy and provide a better understanding of correction geometry in 3CO for thoracolumbar and cervical spinal deformities.

Comparison of Clinical and Radiological Improvement Between the Modified Trephine and High-speed Drill as Main Osteotomy Instrument in Pedicle Subtraction Osteotomy

High-speed drill is the main osteotomy instrument in pedicle subtraction osteotomy (PSO) currently. Considering the long duration of surgery, the large amount of blood loss, and the high incidence of neurovascular injury, the osteotomy procedure is challenging. Use of trephine for the osteotomy displays high efficiency by shortening surgery time and reducing blood loss in anterior cervical corpectomy and fusion. However, the potential risk of neurological injury is high. We modified the trephine by adding locking instrument, when the serrated top of the trephine reaches the tip of the probe; the locking instrument on the probe restricts the trephine and improves security during the osteotomy procedure.The aim of this study was to compare the clinical and radiological improvement between the modified trephine and high-speed drill as main osteotomy instrument in PSO.From February 2009 to 2013, 50 patients with severe thoracolumbar kyphotic deformity caused by old compressive vertebrae were prospectively reviewed. All patients were randomly assigned to the experimental group (27 patients received PSO with modified trephine) and the control group (23 patients received PSO with high-speed drill). The clinical records were reviewed and compared for surgical time, operative blood loss, functional improvement (Oswestry Disability Index), and pain relief (visual analog scale). The radiological records were reviewed and compared for correction of kyphotic deformity postoperatively and correction loss at 2-year follow-up.All patients successfully finished the PSO procedure, and got satisfactory kyphotic deformity correction and overall function improvement. The surgery time was shorter in the experimental group than that in the control group (132.7 ± 12.6 vs 141.7 ± 16.7 min; P = 0.03). No significant difference was found in blood loss (882.9 ± 98.9 mL vs 902.2 ± 84.9 mL; P = 0.47) or correction of the kyphotic angle (33.4 ± 3.4° vs 32.1 ± 2.5°, P = 0.13) postoperatively between the 2 groups. At 24-month follow-up, no difference was discovered in loss of the correction (4.9 ± 1.6° vs 4.5 ± 1.6°; P = 0.42), change of Oswestry Disability Index (49.4 ± 6.2% vs 48.2 ± 4.2%; P = 0.44), or in back pain relief (6.2 ± 1.4 vs 6.4 ± 1.2 min; P = 0.51) between the 2 groups. No internal fixation related complication occurred and bony fusion was detected in lateral X-ray in all patients. In the control group, 2 patients had transient nerve root deficit, 14 patients at 3-month follow-up and 3 patients at 2-year follow-up experienced graft donor site morbidity, and pain killer medicine was always required.In conclusion, the modified trephine obviously shortens surgery time, and prevents graft donor site morbidity when compared to a high-speed drill. The learning curve for using the modified trephine in PSO procedure is short.

Changes in cardiac function after pedicle subtraction osteotomy in patients with a kyphosis due to ankylosing spondylitis

Cardiac disease in patients with ankylosing spondylitis (AS) has previously been studied but not in patients with a kyphosis or in those who have undergone an operation to correct it.

The aim of this study was to measure the post-operative changes in cardiac function of patients with an AS kyphosis after pedicle subtraction osteotomy (PSO).

The original cohort consisted of 39 patients (33 men, six women). Of these, four patients (two men, two women) were lost to follow-up leaving 35 patients (31 men, four women) to study. The mean age of the remaining patients was 37.4 years (22.3 to 47.8) and their mean duration of AS was 17.0 years (4.6 to 26.4). Echocardiographic measurements, resting heart rate (RHR), physical function score (PFS), and full-length standing spinal radiographs were obtained before surgery and at the two-year follow-up.

The mean pre-operative RHR was 80.2 bpm (60.6 to 112.3) which dropped to a mean of 73.7 bpm (60.7 to 90.6) at the two-year follow-up (p = 0.0000). Of 15 patients with normal ventricular function pre-operatively, two developed mild left ventricular diastolic dysfunction (LVDD) at the two-year follow-up. Of 20 patients with mild LVDD pre-operatively only five had this post-operatively. Overall, 15 patients had normal LV diastolic function before their operation and 28 patients had normal LV function at the two-year follow-up.

The clinical improvement was 15 out of 20 (75.0%): cardiac function in patients with AS whose kyphosis was treated by PSO was significantly improved.

Cite this article: Bone Joint J 2015;97-B:1405–10.

Lung volume change after pedicle subtraction osteotomy in patients with ankylosing spondylitis with thoracolumbar kyphosis

STUDY DESIGN

A retrospective clinical study.

OBJECTIVE

To investigate the lung volume (LV) change in patients with ankylosing spondylitis (AS) with thoracolumbar kyphosis after the pedicle subtraction osteotomy procedure.

SUMMARY OF BACKGROUND DATA

Thoracolumbar kyphosis with respiratory impairment is the consequence of most untreated AS patients. Restrictive pulmonary function is prevalent in these patients. The ideal evidence for restrictive pulmonary function impairment is to investigate the LV. A computed tomography (CT)-based method can help to obtain accurate LV change during the osteotomy.

METHOD

Twenty-eight patients with AS with thoracolumbar kyphosis were included. All of these patients underwent pedicle subtraction osteotomy to correct their sagittal deformity. Pre- and postoperative full-length radiographs and CT scans were reviewed. The sagittal correction of the spine was measured. CT scans were used to estimate the pre- and postoperative LV with software. The relationship between the sagittal correction and the LV change was investigated. All the patients were followed up for 2 years at least.

RESULTS

The pedicle subtraction osteotomy procedure was performed safely on each patient without serious complications. The average preoperative T1-S1 Cobb was 67.7° (42°∼88°) and the postoperative was 7.6° (-11°∼21°). T1-S1 Cobb change was 60.0° in average (P < 0.05). The LV increased by 396 mL in average. Significant correlation was found between the percentage of LV change and T1-S1 Cobb change (r = 0.7219, P < 0.05). The location we selected for pedicle subtraction osteotomy varied from T12 to L3. No relationship was found between the osteotomy location and the LV change.

CONCLUSION

The pedicle subtraction osteotomy effectively corrected the sagittal deformity of patients with AS. LV increased significantly after the osteotomy.

LEVEL OF EVIDENCE

4.