The Spine Journal
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Clinical Study
Spinal osteotomy in ankylosing spondylitis: radiological, clinical, and psychological results Ye-Soo Park, MD, PhD*, Hong-Sik Kim, MD, Seung-Wook Baek, MD Department of Orthopaedic Surgery, Guri Hospital, Hanyang University College of Medicine, Gyungchoon-ro 153, Guri city, Gyunggi-do, Korea Received 29 January 2013; revised 24 October 2013; accepted 7 November 2013
Abstract
BACKGROUND CONTEXT: Little is known about the psychological status in patients with ankylosing spondylitis (AS) before and after correction of fixed sagittal imbalance. PURPOSE: The aim of this study was to evaluate the changes in patients’ psychological status after surgical correction and the existence of a correlation between psychological state and the angle of correction. STUDY DESIGN: A retrospective study was performed to assess radiological and clinical results, and psychological status in patients with AS with fixed kyphotic deformity. PATIENT SAMPLE: The sample comprises 24 patients with AS with fixed sagittal imbalance who underwent one-stage corrective osteotomies at our hospital between March 2006 and May 2010. All of the patients included in this study demonstrated an inability to look straight forward because of severe kyphotic deformities. OUTCOME MEASURE: The radiologic analysis included evaluation of thoracic kyphosis, lumbar lordosis, and the sagittal vertical axis (SVA) of the spine. Clinical assessments were performed with Short Form 36 (SF-36), the Bath Ankylosing Spondylitis Function Index (BASFI), and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Patient psychological status was assessed using the Hospital Anxiety and Depression Questionnaire (HADS) and the Health Locus of Control-Form C Questionnaire (HLC-C). METHODS: Each of the above measurements was recorded before and 1 year after the surgery. The changes derived from each measurement before and after the surgery were evaluated. We also analyze the correlations among the radiological, clinical, psychological, and mental evaluations. RESULTS: Mean thoracic kyphosis changed from 38.5 to 33.3 . Mean lumbar lordosis was corrected from 13.8 to 26.1 , and the SVA was improved from 110.8 mm to 49.7 mm. There was significant improvement in the SF-36, BASDAI, BASFI, HADS, and HLC-C scores. The SVA changes were closely linked to BASFI and psychological status, especially anxiety and depression. CONCLUSIONS: The scores of disease status, general health, and psychological status were improved significantly after correction of kyphotic deformity. And the correction of sagittal imbalance was correlated significantly with anxiety and depression. Ó 2013 Elsevier Inc. All rights reserved.
Keywords:
Ankylosing spondylitis; Kyphotic deformity; Corrective osteotomy; Smith-Petersen osteotomy; Pedicle subtraction osteotomy; Psychological status
Introduction Ankylosing spondylitis (AS) involves ankylosis of the sacroiliac joint as well as gradual ossification of the ligament and FDA device/drug status: Not applicable. Author disclosures: Y-SP: Nothing to disclose. H-SK: Nothing to disclose. S-WB: Nothing to disclose. * Corresponding author. Department of Orthopaedic Surgery, Guri Hospital, Hanyang University College of Medicine, Gyungchoon-ro 153, Guri city, Gyunggi-do, Korea. Tel.: 82-31-560-2316; fax: 82-31-557-8781. E-mail address: [email protected] (Y.-S. Park) 1529-9430/$ - see front matter Ó 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.spinee.2013.11.013
joint capsule around the vertebral body. It causes ankylosis in the scope of spinal movement and, in many cases, it causes spinal deformity that includes many cervical, thoracic, and lumbar segments and accompanying pain [1]. Most cases result in kyphotic deformity, and if this deformity worsens, symptoms such as gait disturbance, difficulty in looking in the forward direction, and deterioration in digestive function because of compression of abdominal organs can appear [2]. As a consequence, AS with kyphotic deformity results in not only great physical disability, but also psychological changes in the patient’s life secondary to social limitations [3].
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Although there has been a recent increased interest in the treatment of AS, there are few studies on the psychological state among such patients. Therefore, this study analyzed changes in patients’ psychological status after surgical correction. The existence of a correlation between psychological state and the angle of correction was also evaluated. We hypothesized that the surgical correction of AS could improve patients’ psychological status.
Methods In this retrospective study, we reviewed the records of 24 patients with AS (20 males and 4 females) with severe kyphotic deformities who underwent one-stage corrective osteotomy at our hospital between March 2006 and May 2010. Radiological and clinical results and psychological status were evaluated for these patients at 1 year after surgery. All patients demonstrated an inability to look straight forward and see the horizon. They were also unable to lie down flat in bed with their heads touching the pillow because of the gradually progressing, extreme kyphotic deformities. These patients also reported limitations in their day-to-day activities because of abdominal viscera compression and subsequent indigestion. Cases of severe limitations in walking, driving, maintaining personal relationships, and activities of daily living caused by the impairment in looking forward and kyphotic deformity were considered indications for surgical intervention. The diagnosis was confirmed based on the Modified New York Criteria for AS [4]. Radiological assessment revealed ossification of the spinal and interspinous ligaments, as well as sclerosis of the sacroiliac joint and the capsule at the facet joint. There was also loss of lumbar lordosis, and the characteristic bamboo spine was also apparent. Each patient was positive for HLA B27. Various spinal intervals were examined in the radiological evaluation using long-cassette standing posteroanterior and lateral spinal radiographs. It was taken while the patients stood in a foot template to ensure a standardized support base with hip and knee extension and shoulder flexion to 45 using positioning poles. The T1–T12 area, used to evaluate thoracic kyphosis, was measured from the upper endplate of T1 to the lower endplate of T12. The L1–L5 area, used to evaluate lumbar lordosis, was measured from the upper endplate of L1 to the lower endplate of L5. The sagittal vertical axis (SVA) of the spine, defined as the shortest horizontal distance between the posterior-superior edge of the sacral endplate and the plumb line from C7, was also measured. Each of the above measurements was recorded before and 1 year after the surgery. For the clinical evaluation, the Bath Ankylosing Spondylitis Function Index (BASFI) [5], which is composed of 10 items, was completed before and 1 year after the surgery to assess physical function and the degree of limitation in
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the patients’ daily lives. The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) [6], composed of six items related to major symptoms, was used to evaluate the state of the disease. Additionally, generic health status was measured using the Short Form (SF)-36 questionnaire [7], which measures eight multi-item dimensions: physical functioning (10 items), role limitations due to physical problems (4 items), role limitations due to emotional problems (3 items), social functioning (2 items), mental health (5 items), energy/vitality (4 items), pain (2 items), and general health perception (5 items). For each dimension, item scores are coded, summed, and transformed on a scale from 0 (worst possible health state measured by the questionnaire) to 100 (best possible health state). Psychological and mental status were measured using two questionnaires before and 1 year after surgery. The Hospital Anxiety and Depression Questionnaire (HADS) [8] is a 14-item self-report measure of anxiety and depression. Seven questions assess anxiety and seven questions assess depression. All items are scored on a four-point scale from 0 to 3. Each domain is scored separately with a possible maximum score of 21, and the higher the score, the higher the level of either anxiety or depression, respectively. The Health Locus of Control–Form C Questionnaire (HLC-C) [9] was also used, because it deals with the concept of internality, as well as the belief in chance, the doctor, and the power of others in relation to the patients’ health. The score is calculated according to the levels of agreement (15strongly disagree; 65strongly agree) with 24 statements about belief in chance, belief in powerful others, and internality. The scores obtained from the statements relevant to each of these three areas are summed to form domain totals with a possible range of 8 to 48. The surgical intervention was a lumbar pedicle subtraction osteotomy (PSO) [10], which corrected and shortened the middle and posterior column without distraction of the anterior column while decancellating the pedicle and posterior vertebral body. When there was a lack of kyphosis correction because of severe thoracic kyphosis, the SmithPetersen osteotomy (SPO) [11] was also conducted. SPSS version 17.0 (IBM SPSS Statistics, IBM Corporation, Chicago, IL, USA) was used for statistical analyses. The results derived from each index before and after the surgery were compared using the Wilcoxon signed rank test. Correlations among the radiological, clinical, psychological, and mental evaluations were analyzed by calculating Spearman’s rank correlation coefficient (r); p values less than .05 were considered statistically significant.
Results A total of 20 men and 4 women were included in this study, and their average age was 38.0 years (30–67). The mean duration of follow-up was 29.6 months (14.8–67.1). Among the 24 patients, median age of reported disease
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Figure. (A) Preoperative lateral view of a 35-year-old man with severe flexion deformity for 10 years. (B) Preoperative standing lateral radiograph demonstrating kyphotic deformity in the thoracolumbar and lumbar spine. (C) Postoperative lateral view after pedicle subtraction osteotomy at the L3. (D) Postoperative standing lateral radiograph at 24 months showing correction of the kyphotic deformity.
onset was 20.7 years (18–35), giving median duration of disease as 17.3 years (9–37). Twenty-one patients worked full- or part-time, three were unable to work or unemployed. Fourteen people had a history of iritis. There were no patients who had a history of psychiatric disorder. There were 17 cases in which only the pedicle subtraction osteotomy was performed. Another six cases underwent the PSO and the SPO, and one case underwent SPO only. Pedicle subtraction osteotomy was performed for 1 case at T12, 3 cases at L1, 4 cases at L2, and 15 cases at L3. SPO was performed for two cases at T9–T10, one case at T10–T11, and four cases at T12–L1. Restoration of the ability to look straight forward and see the horizon was achieved in all patients (Figure). In terms of complications, there was one case of superficial infection that required irrigation. Also, one case showed nonunion at the fractured bone area during the follow-up period. This case had an anterior interbody fusion performed 1 year after the surgery. There were no instances of necrosis, neurologic deficit, blood vessel damage, visual loss, or paralytic ileus, and implant failure or device loosening was not observed.
61.1 mm [11–126]; p5.000), thereby enabling the balance of the sagittal plane to be nearer to normal after the surgery (Table 1). Clinical evaluation The BASDAI score improved significantly from an average of 5.3 points (4.1–6.6) before surgery to an aftersurgery average of 2.3 points (0.4–6.1) (p5.000). The BASFI also significantly improved to 2.0 points (1.0–4.0) postsurgery compared with 5.7 points (3.0–8.5) before surgery (p5.000). The average physical component summary score on the SF-36 was 51.8 points (17.5–76.0) postoperation, compared with 65.8 points (47.5–83.7) afterward; however, the improvement was not statistically significant (p5.097). Nonetheless, the mental component summary was significantly improved from 49.6 points (29.1–63.1) before and to 63.5 points (48.1–71.2) after the procedure (p5.002) (Table 2). Psychological evaluation The patient anxiety score according to the HADS was improved significantly from 7.02 points (3.0–10.5) before
Radiological evaluation According to the radiological results, the average thoracic kyphosis was 38.5 (15–69) before and 33.3 (10–57) after the surgery, resulting in an average correction of 5.2 (1–39) (p5.018). The average lumbar lordosis angle was 13.8 (1–40) before and 26.1 (14–37) after the surgery, resulting in an average correction of 12.3 (3–28) (p5.000). The average SVA before surgery was 110.8 mm (22–206), and was significantly corrected to an average of 49.7 mm (0–101) after surgery (mean correction,
Table 1 Radiological assessment Preoperative
Last follow-up visit p Value
Mean thoracic kyphosis ( ) 38.5 (15–69) 33.3 (10–57) Mean lumbar lordosis ( ) 13.8 (1–40) 26.1 (14–37) Mean sagittal vertical axis, mmy 110.8 (22–206) 49.7 (0–101)
.018* .000* .000*
* p!.05. y Distance between the vertical line at the C7 midpoint and the posterosuperior corner of S1.
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Table 2 Clinical assessment
5.3 (4.1–6.6)
2.0 (1.0–4.0)
51.8 (17.5–76.0) 49.6 (29.1–63.1)
Last follow-up visit
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2.3 (0.4–6.1)
5.7 (3.0–8.5)
65.8 (47.5–83.7) 63.5 (48.1–71.2)
p Value .000*
.000*
.097 .002*
PCS, Physical Compont Summary; MCS, Mental component Summary. * p!.05.
to 3.0 points (1.0–6.0) after (p5.000). Patient depression also improved significantly from 6.4 points (2.0–9.5) before to 2.3 points (1.0–4.0) after the surgery (p5.000). All items comprising the HLC-C score were significantly improved. These findings included 28.7 points (10.0–35.0) before and 14.3 points (7.0–20.0) after the surgery for ‘‘internality,’’ 24.9 points (8.0–28.0) before and 14.29 points (6.0–17.0) after the surgery for ‘‘chance,’’ and 25.5 points (6.0–33.0) before and 13.8 points (4.0–16.0) after the surgery for ‘‘other people’’ (p5.000, .000, and .000, respectively) (Table 3). Correlations among the results of radiological, clinical, and psychological evaluations A significant correlation between the difference in thoracic kyphosis angle and lumbar lordosis angle before and after the surgery and BASFI score was not detected (p5.489 and .862, respectively). However, the correlation between SVA correction and BASFI score was statistically significant, (r50.510, p5.011). Significant correlations between the degree of the improvement in the BADAI score, and either the corrected angle of the thoracic kyphosis (p5.269) or the SVA (p5.642) were not detected; however, the degree of lumbar lordosis correction was significantly correlated with BADAI score (r50.463, p5.023). The change in the SF-36 physical component summary score was not significantly correlated with the thoracic Table 3 Psychological assessment Preoperative
Last follow-up visit
Hospital Anxiety and Depression Questionnaire Anxiety 7.0 (3.0–10.5) 3.0 Depression 6.4 (2.0–9.5) 2.3 Health Locus of Control–Form C Questionnaire Internality 28.7 (10.0–35.0) 14.3 Belief in the power 24.9 (8.0–28.0) 14.29 of others Belief in chance 25.5 (6.0–33.0) 13.8 * p!.05.
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Table 4 Correlations between radiologic results and clinical scores Preoperative
Bath Ankylosing Spondylitis Disease Activity Index Bath Ankylosing Spondylitis Function Index Short Form-36 PCS MCS
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p Value
(1.0–6.0) (1.0–4.0)
.000* .000*
(7.0–20.0) (6.0–17.0)
.000* .000*
(4.0–16.0)
.000*
Thoracic kyphosis BASDAI BASFI SF-36 MCS PCS Lumbar lordosis BASDAI BASFI SF-36 MCS PCS Sagittal vertical axisy BASDAI BASFI SF-36 MCS PCS
Correlation coefficient (r)
p Value
0.235 0.148
.269 .489
0.306 0.486
.146 .016*
0.463 0.037
.023* .862
0.182 0.014
.394 .948
0.100 0.510 0.019 0.163
.642 .011* .930 .446
BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Function Index; SF-36, Short Form-36; PCS, Physical Component Summary; MCS, Mental Component Summary. Note: Correlations between variables were assessed according to Spearman’s rank correlation coefficients (rs). * p!.05. y Distance between the vertical line at the C7 midpoint and the posterosuperior corner of S1.
kyphosis angle, the degree of lumbar lordosis angle increase, or the degree of SVA correction (p5.116, .948, and .446, respectively). The change in the SF-36 mental component summary score was not significantly correlated with the thoracic kyphosis angle, the degree of lumbar lordosis angle increase, or the degree of SVA correction (p5.146, .394, and .930, respectively) (Table 4). We also examined the relationship between the psychological evaluation parameters and the radiologic results. The change in HADS score in terms of anxiety was not significantly correlated with the thoracic kyphosis angle or the degree of lumbar lordosis angle correction (p5.888, .851, respectively); however, HADS score was significantly correlated with the degree of SVA correction (r50.536, p5.007). The thoracic kyphosis angle and the degree of lumbar lordosis angle correction were not significantly correlated with the HADS depression score (p5.484 and .812, respectively); however, HADS depression score was significantly correlated with the degree of SVA correction (r50.477, p5.018). The ‘‘internality’’ score on the HLC-C was significantly correlated with the degree of thoracic kyphosis angle correction scoring (r50.434, p5.034); however, this score was not correlated with the degree of lumbar lordosis angle correction or the degree of SVA correction (p5.142 and .291, respectively). Neither the ‘‘chance’’ score nor the ‘‘other person’’ score was significantly correlated with any of the three radiologic parameters (chance: p5.366, .949, and .857; other person: p5.973, .354, and .372) (Table 5).
Y.-S. Park et al. / The Spine Journal Table 5 Correlations between radiological results and psychological scores
Thoracic kyphosis Anxiety Depression Internality Belief in the power of others Belief in chance Lumbar lordosis Anxiety Depression Internality Belief in the power of others Belief in chance Sagittal vertical axisy Anxiety Depression Internality Belief in the power of others Belief in chance
Correlation coefficient (r)
p Value
0.030 0.150 0.434 0.007 0.193
.888 .484 .034* .973 .366
0.040 0.051 0.309 0.198 0.014
.851 .812 .142 .354 .949
0.536 0.477 0.225 0.191 0.039
.004* .018* .291 .372 .857
Note: Correlations between variables were assessed according to Spearman’s rank correlation coefficients (rs). * p!.05. y Distance between the vertical line at the C7 midpoint and the posterosuperior corner of S1.
Discussion When a patient has a kyphotic deformity progressed by AS, the patient complains of constant pain as well as numerous inconveniences in daily life. The loss of the ability to stand upright resulting in an inability to look straight forward and see the horizon has important quality-of-life implications [12,13] in that it can result in depression, which has detrimental effects on a patient’s social life [3]. Since the execution of osteotomy in the lumbar area by Smith-Petersen at al. [11], many scholars have reported lumbar osteotomy results [10,12,14–17]. However, most of the reports of osteotomy for the treatment of kyphotic deformity caused by AS dealt with corrective methodological approaches emphasizing the reduction of postsurgical complications [14–17]. Thus, the dynamic clinical outcomes and psychological status after correcting the kyphotic deformity in patients with AS have not been reported. So, we analyzed changes of clinical outcomes and psychological status in patients with AS after surgical correction. Barlow et al. [18] reported that approximately one-third of patients with AS showed symptoms of depression. The features of this depression included a high internal locus of control and a low reliance on others who were seen as more powerful. Gunther et al. [19] reported that patients with AS tend to give up easily in high-stress situations, and they concluded this tendency was unrelated to disease duration. In addition, Martindale et al. [3] analyzed the relationship between the psychological status of patients with AS and the disease, and found that the severity of the disease was significantly correlated with patients’ psychological and mental state, especially anxiety, depression, and internality.
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Therefore, our study was initiated to compare clinical and psychological evaluation results of patients with AS before and after a suitable surgical intervention to correct the kyphosis. Disease status was analyzed before and after surgery based on BASFI and BASDAI scores. Patient general health status and quality of life improvement were evaluated according to SF-36 scores. Changes in anxiety and depression were evaluated using the HADS score, and changes in internality, belief in chance, doctors, and the power of others in terms of health status were assessed using the HLC-C score. BASFI and BASDAI scores were significantly improved after surgery. However, only the degree of SVA correction was significantly correlated with BASFI score. Additionally, the degree of lumbar lordosis angle correction and BASDAI were significantly correlated. Because BASDAI and BASFI indicate the severity of the disease, it seems that these scores are more likely to be related to disease-treating medication than to the results of the corrective osteotomy. Also, the improvement in BASFI and BASDAI scores after surgery seems to be related to the appropriateness of the disease-treating drug rather than the corrective osteotomy. The physical component summary of the SF-36, which assesses factors including pain and general health, was improved after surgery, but the improvement was not significant. However, the mental component summary of the SF-36 was significantly improved postoperation. The reason for the lack of significance in the physical component summary score can be attributed to the fact that pain and general health are more related to disease severity than the corrective osteotomy. The significant improvement in the mental component summary score after the corrective osteotomy was due to restored patient confidence in that the ability to look straight forward and see the horizon was restored as a result of enhanced sagittal balance. The anxiety and depression scores on the HADS were significantly improved after the corrective osteotomy, as were all items comprising the HLC-C, which were a psychological and mental assessment as well as internality, belief in chance, and belief in the power of others. The restoration of the ability to look straight forward and see the horizon and the enhanced sagittal balance improved physical function and also the psychological stability and mental health of the patients. In fact, the patients expressed subjective satisfaction in the dynamic changes in their lives as a result of the restoration of the ability to look straight forward. Clinical and psychological features were not significantly correlated with the thoracic kyphosis angle or the degree of lumbar lordosis angle correction. However, these features were significantly correlated with the change in the SVA as well as the level of anxiety and depression. Also, a significant correlation was observed between internality and the degree of the thoracic kyphosis angle. These findings imply that the difference in patient psychological status after surgery reflects a sense of relief from the distress
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originating from external, functional, and psychological failure experienced before the surgery rather than the degree of anatomical transformation. Based on objective indices, improvement in the quality of life enhanced patients’ mental and physical health after corrective osteotomy for kyphosis of AS. The degree of sagittal balance before and after the surgery was closely correlated with the patients’ mental health. In this study, there are several potential limitations. First, the results derived were based on short-term follow-up, as patients were monitored for just over a year. A longer follow-up is required to evaluate the potential loss of the correction resulting in a relapse of the kyphosis and the influence relapse has on the clinical and psychological/mental health of the patients. Bridwell et al. [20] analyzed 27 consecutive patients in whom sagittal imbalance was treated with PSO for a minimum of 2 years of follow-up. There was not any substantial loss of correction, except in one patient who had had a pseudarthrosis at the site of the corrective osteotomy. They reported that loss of correction was not observed when the corrective osteotomy had been performed through a previous fusion. All subjects of this study were patients with AS associated with fused spine caused by ossification around the vertebral body. So, we can assume that there would not significantly affect loss of correction and changes thereof in clinical and psychological/mental health with more than a year over. Second, there were only 24 subjects in this study. Although sample size was small, this study is a worthwhile because analysis about interrelation between the corrective surgery and the changes of clinical, psychological, and mental outcomes in patients with AS is especially uncommon. In future study, more definitive results could be obtained with a larger sample size. Conclusion The use of corrective osteotomy for treating kyphosis of ankylosing spondylitis can improve quality of life by improving the psychological and physical health of patients. The degree of sagittal balance before and after surgery is thought to be closely correlated with patient mental health. Psychological and mental evaluation of patients with AS with kyphotic deformity should be implemented. Acknowledgments Conflict of Interest: The manuscript submitted does not contain information about medical device(s)/drug(s). No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
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Approved for the study from the institutional review board on Human Subjects Research and Ethics Committees.
References [1] Lichtblau PO, Wilson PD. Possible mechanism of aortic rupture in orthopaedic correction of rheumatoid spondylitis. J Bone Joint Surg Am 1956;38-A:123–7. [2] Kim KT, Suk KS, Cho YJ, et al. Clinical outcome results of pedicle subtraction osteotomy in ankylosing spondylitis with kyphotic deformity. Spine 2002;27:612–8. [3] Martindale J, Smith J, Sutton CJ, et al. Disease and psychological status in ankylosing spondylitis. Rheumatology (Oxford) 2006;45: 1288–93. [4] van der Linden S, Valkenburg HA, Cats A. Evaluation of diagnostic criteria for ankylosing spondylitis. A proposal for modification of the New York criteria. Arthritis Rheum 1984;27:361–8. [5] Calin A, Garrett S, Whitelock H, et al. A new approach to defining functional ability in ankylosing spondylitis: the development of the Bath Ankylosing Spondylitis Functional Index. J Rheumatol 1994;21: 2281–5. [6] Garrett S, Jenkinson T, Kennedy LG, et al. A new approach to defining disease status in ankylosing spondylitis: the Bath Ankylosing Spondylitis Disease Activity Index. J Rheumatol 1994;21:2286–91. [7] Ware JE Jr, Sherbourne CD. The MOS 36-item short-form health survey (SF-36). I. Conceptual framework and item selection. Med Care 1992;30:473–83. [8] Zigmond AS, Snaith RP. The hospital anxiety and depression scale. Acta Psychiatr Scand 1983;67:361–70. [9] Wallston KA, Stein MJ, Smith CA. Form C of the MHLC scales: a condition-specific measure of locus of control. J Pers Assess 1994;63: 534–53. [10] Thomasen E. Vertebral osteotomy for correction of kyphosis in ankylosing spondylitis. Clin Orthop Relat Res 1985;142–52. [11] Smith-Petersen MN, Larson CB, Aufranc OE. Osteotomy of the spine for correction of flexion deformity in rheumatoid arthritis. Clin Orthop Relat Res 1969;66:6–9. [12] Goel MK. Vertebral osteotomy for correction of fixed flexion deformity of the spine. J Bone Joint Surg Am 1968;50:287–94. [13] La CE. Osteotomy of the lumbar spine for correction of kyphosis in a case of ankylosing spondyloarthritis. J Bone Joint Surg Am 1946;28: 851–8. [14] Chen IH, Chien JT, Yu TC. Transpedicular wedge osteotomy for correction of thoracolumbar kyphosis in ankylosing spondylitis: experience with 78 patients. Spine 2001;26:E354–60. [15] Murrey DB, Brigham CD, Kiebzak GM, et al. Transpedicular decompression and pedicle subtraction osteotomy (eggshell procedure): a retrospective review of 59 patients. Spine 2002;27:2338–45. [16] Willems KF, Slot GH, Anderson PG, et al. Spinal osteotomy in patients with ankylosing spondylitis: complications during first postoperative year. Spine 2005;30:101–7. [17] Rose PS, Bridwell KH, Lenke LG, et al. Role of pelvic incidence, thoracic kyphosis, and patient factors on sagittal plane correction following pedicle subtraction osteotomy. Spine 2009;34:785–91. [18] Barlow JH, Macey SJ, Struthers GR. Gender, depression, and ankylosing spondylitis. Arthritis Care Res 1993;6:45–51. [19] Gunther V, Mur E, Traweger C, Hawel R. Stress coping of patients with ankylosing spondylitis. J Psychosom Res 1994;38:419–27. [20] Bridwell KH, Lewis SJ, Lenke LG, et al. Pedicle subtraction osteotomy for the treatment of fixed sagittal imbalance. J Bone Joint Surg Am 2003;85-A:454–63.
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Clinical Study
Spinal osteotomy in ankylosing spondylitis: radiological, clinical, and psychological results Ye-Soo Park, MD, PhD*, Hong-Sik Kim, MD, Seung-Wook Baek, MD Department of Orthopaedic Surgery, Guri Hospital, Hanyang University College of Medicine, Gyungchoon-ro 153, Guri city, Gyunggi-do, Korea Received 29 January 2013; revised 24 October 2013; accepted 7 November 2013
Abstract
BACKGROUND CONTEXT: Little is known about the psychological status in patients with ankylosing spondylitis (AS) before and after correction of fixed sagittal imbalance. PURPOSE: The aim of this study was to evaluate the changes in patients’ psychological status after surgical correction and the existence of a correlation between psychological state and the angle of correction. STUDY DESIGN: A retrospective study was performed to assess radiological and clinical results, and psychological status in patients with AS with fixed kyphotic deformity. PATIENT SAMPLE: The sample comprises 24 patients with AS with fixed sagittal imbalance who underwent one-stage corrective osteotomies at our hospital between March 2006 and May 2010. All of the patients included in this study demonstrated an inability to look straight forward because of severe kyphotic deformities. OUTCOME MEASURE: The radiologic analysis included evaluation of thoracic kyphosis, lumbar lordosis, and the sagittal vertical axis (SVA) of the spine. Clinical assessments were performed with Short Form 36 (SF-36), the Bath Ankylosing Spondylitis Function Index (BASFI), and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Patient psychological status was assessed using the Hospital Anxiety and Depression Questionnaire (HADS) and the Health Locus of Control-Form C Questionnaire (HLC-C). METHODS: Each of the above measurements was recorded before and 1 year after the surgery. The changes derived from each measurement before and after the surgery were evaluated. We also analyze the correlations among the radiological, clinical, psychological, and mental evaluations. RESULTS: Mean thoracic kyphosis changed from 38.5 to 33.3 . Mean lumbar lordosis was corrected from 13.8 to 26.1 , and the SVA was improved from 110.8 mm to 49.7 mm. There was significant improvement in the SF-36, BASDAI, BASFI, HADS, and HLC-C scores. The SVA changes were closely linked to BASFI and psychological status, especially anxiety and depression. CONCLUSIONS: The scores of disease status, general health, and psychological status were improved significantly after correction of kyphotic deformity. And the correction of sagittal imbalance was correlated significantly with anxiety and depression. Ó 2013 Elsevier Inc. All rights reserved.
Keywords:
Ankylosing spondylitis; Kyphotic deformity; Corrective osteotomy; Smith-Petersen osteotomy; Pedicle subtraction osteotomy; Psychological status
Introduction Ankylosing spondylitis (AS) involves ankylosis of the sacroiliac joint as well as gradual ossification of the ligament and FDA device/drug status: Not applicable. Author disclosures: Y-SP: Nothing to disclose. H-SK: Nothing to disclose. S-WB: Nothing to disclose. * Corresponding author. Department of Orthopaedic Surgery, Guri Hospital, Hanyang University College of Medicine, Gyungchoon-ro 153, Guri city, Gyunggi-do, Korea. Tel.: 82-31-560-2316; fax: 82-31-557-8781. E-mail address: [email protected] (Y.-S. Park) 1529-9430/$ - see front matter Ó 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.spinee.2013.11.013
joint capsule around the vertebral body. It causes ankylosis in the scope of spinal movement and, in many cases, it causes spinal deformity that includes many cervical, thoracic, and lumbar segments and accompanying pain [1]. Most cases result in kyphotic deformity, and if this deformity worsens, symptoms such as gait disturbance, difficulty in looking in the forward direction, and deterioration in digestive function because of compression of abdominal organs can appear [2]. As a consequence, AS with kyphotic deformity results in not only great physical disability, but also psychological changes in the patient’s life secondary to social limitations [3].
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Although there has been a recent increased interest in the treatment of AS, there are few studies on the psychological state among such patients. Therefore, this study analyzed changes in patients’ psychological status after surgical correction. The existence of a correlation between psychological state and the angle of correction was also evaluated. We hypothesized that the surgical correction of AS could improve patients’ psychological status.
Methods In this retrospective study, we reviewed the records of 24 patients with AS (20 males and 4 females) with severe kyphotic deformities who underwent one-stage corrective osteotomy at our hospital between March 2006 and May 2010. Radiological and clinical results and psychological status were evaluated for these patients at 1 year after surgery. All patients demonstrated an inability to look straight forward and see the horizon. They were also unable to lie down flat in bed with their heads touching the pillow because of the gradually progressing, extreme kyphotic deformities. These patients also reported limitations in their day-to-day activities because of abdominal viscera compression and subsequent indigestion. Cases of severe limitations in walking, driving, maintaining personal relationships, and activities of daily living caused by the impairment in looking forward and kyphotic deformity were considered indications for surgical intervention. The diagnosis was confirmed based on the Modified New York Criteria for AS [4]. Radiological assessment revealed ossification of the spinal and interspinous ligaments, as well as sclerosis of the sacroiliac joint and the capsule at the facet joint. There was also loss of lumbar lordosis, and the characteristic bamboo spine was also apparent. Each patient was positive for HLA B27. Various spinal intervals were examined in the radiological evaluation using long-cassette standing posteroanterior and lateral spinal radiographs. It was taken while the patients stood in a foot template to ensure a standardized support base with hip and knee extension and shoulder flexion to 45 using positioning poles. The T1–T12 area, used to evaluate thoracic kyphosis, was measured from the upper endplate of T1 to the lower endplate of T12. The L1–L5 area, used to evaluate lumbar lordosis, was measured from the upper endplate of L1 to the lower endplate of L5. The sagittal vertical axis (SVA) of the spine, defined as the shortest horizontal distance between the posterior-superior edge of the sacral endplate and the plumb line from C7, was also measured. Each of the above measurements was recorded before and 1 year after the surgery. For the clinical evaluation, the Bath Ankylosing Spondylitis Function Index (BASFI) [5], which is composed of 10 items, was completed before and 1 year after the surgery to assess physical function and the degree of limitation in
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the patients’ daily lives. The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) [6], composed of six items related to major symptoms, was used to evaluate the state of the disease. Additionally, generic health status was measured using the Short Form (SF)-36 questionnaire [7], which measures eight multi-item dimensions: physical functioning (10 items), role limitations due to physical problems (4 items), role limitations due to emotional problems (3 items), social functioning (2 items), mental health (5 items), energy/vitality (4 items), pain (2 items), and general health perception (5 items). For each dimension, item scores are coded, summed, and transformed on a scale from 0 (worst possible health state measured by the questionnaire) to 100 (best possible health state). Psychological and mental status were measured using two questionnaires before and 1 year after surgery. The Hospital Anxiety and Depression Questionnaire (HADS) [8] is a 14-item self-report measure of anxiety and depression. Seven questions assess anxiety and seven questions assess depression. All items are scored on a four-point scale from 0 to 3. Each domain is scored separately with a possible maximum score of 21, and the higher the score, the higher the level of either anxiety or depression, respectively. The Health Locus of Control–Form C Questionnaire (HLC-C) [9] was also used, because it deals with the concept of internality, as well as the belief in chance, the doctor, and the power of others in relation to the patients’ health. The score is calculated according to the levels of agreement (15strongly disagree; 65strongly agree) with 24 statements about belief in chance, belief in powerful others, and internality. The scores obtained from the statements relevant to each of these three areas are summed to form domain totals with a possible range of 8 to 48. The surgical intervention was a lumbar pedicle subtraction osteotomy (PSO) [10], which corrected and shortened the middle and posterior column without distraction of the anterior column while decancellating the pedicle and posterior vertebral body. When there was a lack of kyphosis correction because of severe thoracic kyphosis, the SmithPetersen osteotomy (SPO) [11] was also conducted. SPSS version 17.0 (IBM SPSS Statistics, IBM Corporation, Chicago, IL, USA) was used for statistical analyses. The results derived from each index before and after the surgery were compared using the Wilcoxon signed rank test. Correlations among the radiological, clinical, psychological, and mental evaluations were analyzed by calculating Spearman’s rank correlation coefficient (r); p values less than .05 were considered statistically significant.
Results A total of 20 men and 4 women were included in this study, and their average age was 38.0 years (30–67). The mean duration of follow-up was 29.6 months (14.8–67.1). Among the 24 patients, median age of reported disease
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Figure. (A) Preoperative lateral view of a 35-year-old man with severe flexion deformity for 10 years. (B) Preoperative standing lateral radiograph demonstrating kyphotic deformity in the thoracolumbar and lumbar spine. (C) Postoperative lateral view after pedicle subtraction osteotomy at the L3. (D) Postoperative standing lateral radiograph at 24 months showing correction of the kyphotic deformity.
onset was 20.7 years (18–35), giving median duration of disease as 17.3 years (9–37). Twenty-one patients worked full- or part-time, three were unable to work or unemployed. Fourteen people had a history of iritis. There were no patients who had a history of psychiatric disorder. There were 17 cases in which only the pedicle subtraction osteotomy was performed. Another six cases underwent the PSO and the SPO, and one case underwent SPO only. Pedicle subtraction osteotomy was performed for 1 case at T12, 3 cases at L1, 4 cases at L2, and 15 cases at L3. SPO was performed for two cases at T9–T10, one case at T10–T11, and four cases at T12–L1. Restoration of the ability to look straight forward and see the horizon was achieved in all patients (Figure). In terms of complications, there was one case of superficial infection that required irrigation. Also, one case showed nonunion at the fractured bone area during the follow-up period. This case had an anterior interbody fusion performed 1 year after the surgery. There were no instances of necrosis, neurologic deficit, blood vessel damage, visual loss, or paralytic ileus, and implant failure or device loosening was not observed.
61.1 mm [11–126]; p5.000), thereby enabling the balance of the sagittal plane to be nearer to normal after the surgery (Table 1). Clinical evaluation The BASDAI score improved significantly from an average of 5.3 points (4.1–6.6) before surgery to an aftersurgery average of 2.3 points (0.4–6.1) (p5.000). The BASFI also significantly improved to 2.0 points (1.0–4.0) postsurgery compared with 5.7 points (3.0–8.5) before surgery (p5.000). The average physical component summary score on the SF-36 was 51.8 points (17.5–76.0) postoperation, compared with 65.8 points (47.5–83.7) afterward; however, the improvement was not statistically significant (p5.097). Nonetheless, the mental component summary was significantly improved from 49.6 points (29.1–63.1) before and to 63.5 points (48.1–71.2) after the procedure (p5.002) (Table 2). Psychological evaluation The patient anxiety score according to the HADS was improved significantly from 7.02 points (3.0–10.5) before
Radiological evaluation According to the radiological results, the average thoracic kyphosis was 38.5 (15–69) before and 33.3 (10–57) after the surgery, resulting in an average correction of 5.2 (1–39) (p5.018). The average lumbar lordosis angle was 13.8 (1–40) before and 26.1 (14–37) after the surgery, resulting in an average correction of 12.3 (3–28) (p5.000). The average SVA before surgery was 110.8 mm (22–206), and was significantly corrected to an average of 49.7 mm (0–101) after surgery (mean correction,
Table 1 Radiological assessment Preoperative
Last follow-up visit p Value
Mean thoracic kyphosis ( ) 38.5 (15–69) 33.3 (10–57) Mean lumbar lordosis ( ) 13.8 (1–40) 26.1 (14–37) Mean sagittal vertical axis, mmy 110.8 (22–206) 49.7 (0–101)
.018* .000* .000*
* p!.05. y Distance between the vertical line at the C7 midpoint and the posterosuperior corner of S1.
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Table 2 Clinical assessment
5.3 (4.1–6.6)
2.0 (1.0–4.0)
51.8 (17.5–76.0) 49.6 (29.1–63.1)
Last follow-up visit
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2.3 (0.4–6.1)
5.7 (3.0–8.5)
65.8 (47.5–83.7) 63.5 (48.1–71.2)
p Value .000*
.000*
.097 .002*
PCS, Physical Compont Summary; MCS, Mental component Summary. * p!.05.
to 3.0 points (1.0–6.0) after (p5.000). Patient depression also improved significantly from 6.4 points (2.0–9.5) before to 2.3 points (1.0–4.0) after the surgery (p5.000). All items comprising the HLC-C score were significantly improved. These findings included 28.7 points (10.0–35.0) before and 14.3 points (7.0–20.0) after the surgery for ‘‘internality,’’ 24.9 points (8.0–28.0) before and 14.29 points (6.0–17.0) after the surgery for ‘‘chance,’’ and 25.5 points (6.0–33.0) before and 13.8 points (4.0–16.0) after the surgery for ‘‘other people’’ (p5.000, .000, and .000, respectively) (Table 3). Correlations among the results of radiological, clinical, and psychological evaluations A significant correlation between the difference in thoracic kyphosis angle and lumbar lordosis angle before and after the surgery and BASFI score was not detected (p5.489 and .862, respectively). However, the correlation between SVA correction and BASFI score was statistically significant, (r50.510, p5.011). Significant correlations between the degree of the improvement in the BADAI score, and either the corrected angle of the thoracic kyphosis (p5.269) or the SVA (p5.642) were not detected; however, the degree of lumbar lordosis correction was significantly correlated with BADAI score (r50.463, p5.023). The change in the SF-36 physical component summary score was not significantly correlated with the thoracic Table 3 Psychological assessment Preoperative
Last follow-up visit
Hospital Anxiety and Depression Questionnaire Anxiety 7.0 (3.0–10.5) 3.0 Depression 6.4 (2.0–9.5) 2.3 Health Locus of Control–Form C Questionnaire Internality 28.7 (10.0–35.0) 14.3 Belief in the power 24.9 (8.0–28.0) 14.29 of others Belief in chance 25.5 (6.0–33.0) 13.8 * p!.05.
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Table 4 Correlations between radiologic results and clinical scores Preoperative
Bath Ankylosing Spondylitis Disease Activity Index Bath Ankylosing Spondylitis Function Index Short Form-36 PCS MCS
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p Value
(1.0–6.0) (1.0–4.0)
.000* .000*
(7.0–20.0) (6.0–17.0)
.000* .000*
(4.0–16.0)
.000*
Thoracic kyphosis BASDAI BASFI SF-36 MCS PCS Lumbar lordosis BASDAI BASFI SF-36 MCS PCS Sagittal vertical axisy BASDAI BASFI SF-36 MCS PCS
Correlation coefficient (r)
p Value
0.235 0.148
.269 .489
0.306 0.486
.146 .016*
0.463 0.037
.023* .862
0.182 0.014
.394 .948
0.100 0.510 0.019 0.163
.642 .011* .930 .446
BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Function Index; SF-36, Short Form-36; PCS, Physical Component Summary; MCS, Mental Component Summary. Note: Correlations between variables were assessed according to Spearman’s rank correlation coefficients (rs). * p!.05. y Distance between the vertical line at the C7 midpoint and the posterosuperior corner of S1.
kyphosis angle, the degree of lumbar lordosis angle increase, or the degree of SVA correction (p5.116, .948, and .446, respectively). The change in the SF-36 mental component summary score was not significantly correlated with the thoracic kyphosis angle, the degree of lumbar lordosis angle increase, or the degree of SVA correction (p5.146, .394, and .930, respectively) (Table 4). We also examined the relationship between the psychological evaluation parameters and the radiologic results. The change in HADS score in terms of anxiety was not significantly correlated with the thoracic kyphosis angle or the degree of lumbar lordosis angle correction (p5.888, .851, respectively); however, HADS score was significantly correlated with the degree of SVA correction (r50.536, p5.007). The thoracic kyphosis angle and the degree of lumbar lordosis angle correction were not significantly correlated with the HADS depression score (p5.484 and .812, respectively); however, HADS depression score was significantly correlated with the degree of SVA correction (r50.477, p5.018). The ‘‘internality’’ score on the HLC-C was significantly correlated with the degree of thoracic kyphosis angle correction scoring (r50.434, p5.034); however, this score was not correlated with the degree of lumbar lordosis angle correction or the degree of SVA correction (p5.142 and .291, respectively). Neither the ‘‘chance’’ score nor the ‘‘other person’’ score was significantly correlated with any of the three radiologic parameters (chance: p5.366, .949, and .857; other person: p5.973, .354, and .372) (Table 5).
Y.-S. Park et al. / The Spine Journal Table 5 Correlations between radiological results and psychological scores
Thoracic kyphosis Anxiety Depression Internality Belief in the power of others Belief in chance Lumbar lordosis Anxiety Depression Internality Belief in the power of others Belief in chance Sagittal vertical axisy Anxiety Depression Internality Belief in the power of others Belief in chance
Correlation coefficient (r)
p Value
0.030 0.150 0.434 0.007 0.193
.888 .484 .034* .973 .366
0.040 0.051 0.309 0.198 0.014
.851 .812 .142 .354 .949
0.536 0.477 0.225 0.191 0.039
.004* .018* .291 .372 .857
Note: Correlations between variables were assessed according to Spearman’s rank correlation coefficients (rs). * p!.05. y Distance between the vertical line at the C7 midpoint and the posterosuperior corner of S1.
Discussion When a patient has a kyphotic deformity progressed by AS, the patient complains of constant pain as well as numerous inconveniences in daily life. The loss of the ability to stand upright resulting in an inability to look straight forward and see the horizon has important quality-of-life implications [12,13] in that it can result in depression, which has detrimental effects on a patient’s social life [3]. Since the execution of osteotomy in the lumbar area by Smith-Petersen at al. [11], many scholars have reported lumbar osteotomy results [10,12,14–17]. However, most of the reports of osteotomy for the treatment of kyphotic deformity caused by AS dealt with corrective methodological approaches emphasizing the reduction of postsurgical complications [14–17]. Thus, the dynamic clinical outcomes and psychological status after correcting the kyphotic deformity in patients with AS have not been reported. So, we analyzed changes of clinical outcomes and psychological status in patients with AS after surgical correction. Barlow et al. [18] reported that approximately one-third of patients with AS showed symptoms of depression. The features of this depression included a high internal locus of control and a low reliance on others who were seen as more powerful. Gunther et al. [19] reported that patients with AS tend to give up easily in high-stress situations, and they concluded this tendency was unrelated to disease duration. In addition, Martindale et al. [3] analyzed the relationship between the psychological status of patients with AS and the disease, and found that the severity of the disease was significantly correlated with patients’ psychological and mental state, especially anxiety, depression, and internality.
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Therefore, our study was initiated to compare clinical and psychological evaluation results of patients with AS before and after a suitable surgical intervention to correct the kyphosis. Disease status was analyzed before and after surgery based on BASFI and BASDAI scores. Patient general health status and quality of life improvement were evaluated according to SF-36 scores. Changes in anxiety and depression were evaluated using the HADS score, and changes in internality, belief in chance, doctors, and the power of others in terms of health status were assessed using the HLC-C score. BASFI and BASDAI scores were significantly improved after surgery. However, only the degree of SVA correction was significantly correlated with BASFI score. Additionally, the degree of lumbar lordosis angle correction and BASDAI were significantly correlated. Because BASDAI and BASFI indicate the severity of the disease, it seems that these scores are more likely to be related to disease-treating medication than to the results of the corrective osteotomy. Also, the improvement in BASFI and BASDAI scores after surgery seems to be related to the appropriateness of the disease-treating drug rather than the corrective osteotomy. The physical component summary of the SF-36, which assesses factors including pain and general health, was improved after surgery, but the improvement was not significant. However, the mental component summary of the SF-36 was significantly improved postoperation. The reason for the lack of significance in the physical component summary score can be attributed to the fact that pain and general health are more related to disease severity than the corrective osteotomy. The significant improvement in the mental component summary score after the corrective osteotomy was due to restored patient confidence in that the ability to look straight forward and see the horizon was restored as a result of enhanced sagittal balance. The anxiety and depression scores on the HADS were significantly improved after the corrective osteotomy, as were all items comprising the HLC-C, which were a psychological and mental assessment as well as internality, belief in chance, and belief in the power of others. The restoration of the ability to look straight forward and see the horizon and the enhanced sagittal balance improved physical function and also the psychological stability and mental health of the patients. In fact, the patients expressed subjective satisfaction in the dynamic changes in their lives as a result of the restoration of the ability to look straight forward. Clinical and psychological features were not significantly correlated with the thoracic kyphosis angle or the degree of lumbar lordosis angle correction. However, these features were significantly correlated with the change in the SVA as well as the level of anxiety and depression. Also, a significant correlation was observed between internality and the degree of the thoracic kyphosis angle. These findings imply that the difference in patient psychological status after surgery reflects a sense of relief from the distress
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originating from external, functional, and psychological failure experienced before the surgery rather than the degree of anatomical transformation. Based on objective indices, improvement in the quality of life enhanced patients’ mental and physical health after corrective osteotomy for kyphosis of AS. The degree of sagittal balance before and after the surgery was closely correlated with the patients’ mental health. In this study, there are several potential limitations. First, the results derived were based on short-term follow-up, as patients were monitored for just over a year. A longer follow-up is required to evaluate the potential loss of the correction resulting in a relapse of the kyphosis and the influence relapse has on the clinical and psychological/mental health of the patients. Bridwell et al. [20] analyzed 27 consecutive patients in whom sagittal imbalance was treated with PSO for a minimum of 2 years of follow-up. There was not any substantial loss of correction, except in one patient who had had a pseudarthrosis at the site of the corrective osteotomy. They reported that loss of correction was not observed when the corrective osteotomy had been performed through a previous fusion. All subjects of this study were patients with AS associated with fused spine caused by ossification around the vertebral body. So, we can assume that there would not significantly affect loss of correction and changes thereof in clinical and psychological/mental health with more than a year over. Second, there were only 24 subjects in this study. Although sample size was small, this study is a worthwhile because analysis about interrelation between the corrective surgery and the changes of clinical, psychological, and mental outcomes in patients with AS is especially uncommon. In future study, more definitive results could be obtained with a larger sample size. Conclusion The use of corrective osteotomy for treating kyphosis of ankylosing spondylitis can improve quality of life by improving the psychological and physical health of patients. The degree of sagittal balance before and after surgery is thought to be closely correlated with patient mental health. Psychological and mental evaluation of patients with AS with kyphotic deformity should be implemented. Acknowledgments Conflict of Interest: The manuscript submitted does not contain information about medical device(s)/drug(s). No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
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Approved for the study from the institutional review board on Human Subjects Research and Ethics Committees.
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