Does sagittal imbalance impact the surgical outcomes of short-segment fusion for lumbar spinal stenosis associated with degenerative lumbar scoliosis?

Does sagittal imbalance impact the surgical outcomes of short-segment fusion for lumbar spinal stenosis associated with degenerative lumbar scoliosis?

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Journal of Orthopaedic Science xxx (xxxx) xxx

Contents lists available at ScienceDirect

Journal of Orthopaedic Science journal homepage: http://www.elsevier.com/locate/jos

Original Article

Does sagittal imbalance impact the surgical outcomes of shortsegment fusion for lumbar spinal stenosis associated with degenerative lumbar scoliosis?* Yusuke Hori a, Akira Matsumura a, *, Takashi Namikawa a, Minori Kato a, Shinji Takahashi b, Shoichiro Ohyama a, Tomonori Ozaki a, Akito Yabu a, Hiroaki Nakamura b a b

Department of Orthopaedic Surgery, Osaka City General Hospital, Osaka, Japan Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan

a r t i c l e i n f o

a b s t r a c t

Article history: Received 23 January 2018 Received in revised form 27 September 2018 Accepted 1 October 2018 Available online xxx

Background: The degenerative lumbar scoliosis (DLS) patients who mainly complained about neurogenic claudication due to spinal canal stenosis are well-indicated for short segment fusion (SSF) at the affecting levels. However, it is unclear whether we should consider global sagittal balance or not. The aim of this study was to evaluate the impact of sagittal balance on the surgical outcomes of degenerative lumbar scoliosis (DLS) patients who underwent SSF. Methods: We retrospectively reviewed 70 DLS patients who underwent SSF (less than 3 levels) and could be followed for at least 2 years. The PI-LL, PT, SVA, and T1 pelvic angle (TPA) were measured using standing whole spine X-rays preoperatively (PreO) and at final follow-up (FFU). Surgical outcomes were assessed with the improvement in Japanese Orthopaedic Association score (JOAs) for low back pain (LBP), and the level of LBP was measured using the visual analogue scale (LBP-VAS). We analysed the relationships between the radiographic parameters and the surgical outcomes. Results: We divided the patients into the three groups (poor/fair/good) based on the JOAs. The analysis with the Jonckheere-Terpstra trend test indicated that the following radiographic parameters had a significant trend with surgical outcomes in each group: (poor/fair/good; p value); PreO PI-LL (26/20/17 ; P ¼ 0.04), SVA (46/75/35.5 mm; P ¼ 0.02), TPA (28/27/23 ; p ¼ 0.04), FFU PI-LL (33/25/8.5 ; P ¼ 0.004), SVA (93/90.5/32.5 mm; P ¼ 0.001), and TPA (33/29/25 ; P ¼ 0.007). Additionally, LBP-VAS had a significant correlation between the three groups at final follow-up (P ¼ 0.004). There were significant correlations between improvement in JOAs and PI-LL, SVA, and TPA both PreO and at FFU (P < 0.05). Conclusions: Sagittal spinal imbalance and spinopelvic malalignment significantly impact the surgical outcomes of SSF for DLS. Preoperative evaluation of spinopelvic alignment and sagittal balance is of critical importance when SSF are performed for DLS patients. © 2018 Published by Elsevier B.V. on behalf of The Japanese Orthopaedic Association.

1. Introduction The etiology of degenerative lumbar scoliosis (DLS, “de novo” scoliosis) that is commonly present in elderly populations involves disc degeneration and arthritis of the facet joints in the lumbar

*

Study design: Retrospective chart review. * Corresponding author. Department of Orthopaedic Surgery, Osaka City General Hospital, 2-13-22 Miyakojimahondori, Miyakojima-Ku, Osaka, 534-0021, Japan. Fax: þ81 6 6929 2041. E-mail address: [email protected] (A. Matsumura).

spine [1,2]. Aebi [3] presented the classification of DLS based on etiology. He clearly distinguished this type of DLS from adult idiopathic scoliosis, which presents in adolescence or childhood and progresses due to mechanical reasons or bony and/or degenerative changes. The prevalence of DLS, reported to be between 1% and 68% [4e6], is difficult to determine because of the diverse patient populations studied, but most studies have demonstrated a prevalence between 7.5% and 15% [7]. The clinical presentation of DLS varies, but it is frequently associated with low back pain (LBP) and neurogenic claudication [1,3,8]. LBP can be caused by disc degeneration, facet joint arthrosis,

https://doi.org/10.1016/j.jos.2018.10.005 0949-2658/© 2018 Published by Elsevier B.V. on behalf of The Japanese Orthopaedic Association.

Please cite this article as: Hori Y et al., Does sagittal imbalance impact the surgical outcomes of short-segment fusion for lumbar spinal stenosis associated with degenerative lumbar scoliosis?, Journal of Orthopaedic Science, https://doi.org/10.1016/j.jos.2018.10.005

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Y. Hori et al. / Journal of Orthopaedic Science xxx (xxxx) xxx

and sagittal imbalance due to loss of lumbar lordosis [9]. Radicular pain and neurogenic claudication due to spinal canal stenosis or foraminal stenosis are also often present in DLS patients [8]. Surgical strategy and decision making for DLS patients are complex [3]. Surgical procedures vary from simple decompression, short fusion, corrective surgery with long fusion [10e12]. The surgical procedure is typically based on the patient's symptoms. For relieving neurogenic claudication, decompression surgery is essential [1]. Decompression surgery without fusion is thought to be suitable for DLS patients without spinal instability [7,13e15]. Several reports have recommended decompression surgery with segmental fusion for DLS patients with spinal instability [16e19]. On the other hand, major correction surgery with long instrumentation may be considered for DLS patients whose primary complaint is LBP due to spinal deformity [3,20]. As previously mentioned, for DLS patients with neurogenic claudication and segmental instability, short-segment fusion (SSF) is indicated for the affected levels. However, some patients present with sagittal imbalance. To our knowledge, there is no definitive answer as to whether global sagittal balance should be determined in DLS patients with neurogenic claudication due to spinal stenosis. The aim of this study was to evaluate the impact of sagittal alignment and balance on the clinical outcomes of DLS patients with neurogenic claudication who underwent SSF. 2. Materials and methods 2.1. Study design Seventy-seven consecutive DLS patients who underwent decompression with SSF (less than 3 disc levels) between 2008 and 2014 were considered for this study. All patients complained of leg pain and numbness due to neurogenic claudication. Inclusion criteria were as follows: (1) age over 50 years; (2) coronal Cobb angle greater than 10 ; (3) a minimum 2-year follow-up period; and (4) radiographic and clinical data available from before surgery and at final follow-up. Seventy of the 77 patients met our inclusion criteria. Of the 70 patients, 17 patients were male and 53 patients were female. The average age of the patients was 70.5 ± 7.9 years at the surgery. The average follow-up period was 4.1 ± 1.8 (range, 2.0e7.7) years. 2.2. Surgical indications and techniques for SSF We evaluated the spinal alignment and global balance in all patients using plain anterior-posterior and lateral radiographs of lumbar spine and whole spine preoperatively. Segmental spinal instability was assessed using radiographs in the standing and supine positions. Coronal instability was defined as more than a 3degree change of the disc wedge, more than a 5-degree change in Cobb angle, or more than a 3-mm increase of the lateral slip between the supine and standing positions. Magnetic Resonance Imaging (MRI) was performed in all patients to evaluate the lumbar spinal stenosis included central and foraminal stenosis. Decompression and fusion surgery with spinal instrumentation was performed at the affected levels which had segmental spinal instability and spinal stenosis, whereas only decompression was performed at the level of stenosis without instability. As the technique of fusion surgery, unilateral transforaminal lumbar interbody fusion (TLIF) [21] from the concave side was performed to achieve correction of the disc wedge as much as possible while preserving the contralateral side of the facet joint. We didn't perform surgery at the levels which presented instability but were not related to the symptoms. All of fusion areas were included from L2 to S1. Thirtyfour patients underwent one level fusion, 26 underwent two levels fusion, and 10 underwent three levels fusion.

2.3. Outcome measurements We evaluated several radiographic parameters using standing whole spine radiographs preoperatively and at final follow-up. The following radiographical parameters were measured: coronal Cobb angle; pelvic incidence (PI) - lumbar lordosis (LL); pelvic tilt (PT); sagittal vertebral axis (SVA); and T1 pelvic angle (TPA). Surgical outcomes were assessed with the improvement in Japanese Orthopaedic Association score for low back pain (JOAs), and the level of low back pain was measured using the visual analogue scale (LBP-VAS). JOA score was investigated by surgeons or residents. The improvement in JOAs was calculated using the following formula: improvement in JOAs (%) ¼ 100  (final JOA score  preoperative JOA score)÷(29  preoperative JOA score). When JOAs at final follow-up was 29, the improvement was categorized as excellent. We also evaluated the etiology and type of additional surgery. 2.4. Statistical analysis Patients were divided into three groups based on improvement in JOAs: a poor outcome group (less than 25%), a fair outcome group (26e50%), and a good/excellent outcome group (more than 50%). The Fisher's exact test was used for categorical variables and analysis of variance was used for continuous variables. The JonckheereTerpstra trend test was used to evaluate the trend in radiographic parameters and LBP-VAS among the three groups. Multiple linear regression analyses were used to examine the association between the improvement in JOAs and spinal parameters both preoperatively and at final follow-up while adjusting for age and gender. Statistical tests were considered significant at P < 0.05. All P values were two-sided. All analyses were performed using SAS version 9.4 (SAS Institute, Inc., Cary, NC). This study has been approved by the ethics committee of our institution (approval number 1305011). 3. Results Overall, in the 70 DLS patients, mean JOAs improved from 12.9 ± 3.0 to 21.3 ± 4.6 (average improvement was 52.2%). According to the JOAs, we placed 17 patients into the poor outcome group (mean improvement was 13.0%), 13 patients into the fair outcome group (mean improvement was 38.8%), and 40 patients into the good/excellent outcome group (mean improvement was 72.8%). There were no significant differences between the three groups with regards to demographic data such as age and gender, or in the number of spinal levels fused (Table 1). Box plots of preoperative radiographic parameters are shown in Fig. 1. There were significant trends (mean ± SD: poor; fair; good/ excellent, P value) in PI-LL (27.0 ± 13.6; 23.2 ± 13.1; 18.4 ± 11.2, P ¼ 0.039), SVA (54.1 ± 34.9; 73.0 ± 49.2; 34.6 ± 32.4, P ¼ 0.023), and TPA (28.2 ± 9.7; 27.2 ± 12.7; 23.1 ± 8.3, P ¼ 0.042), while there were no significant trend in Cobb angle (20.5 ± 8.8; 26.5 ± 11.3; 27.0 ± 7.7, P ¼ 0.81) or PT (29.9 ± 10.7; 23.2 ± 13.1; 18.4 ± 11.2, P ¼ 0.46). Box plots of radiographic parameters at final follow-up are shown in Fig. 2. There were significant trends at final follow-up in PI-LL Table 1 Demographic data of the three groups divided by improvement in JOA score.

Age Sex (Male: Female) Fusion levels (1:2:3) a b

Poor

Fair

Good/Excellent

P value

68.9 ± 9.3 5: 12 6: 9: 2

74.2 ± 7.4 1: 12 6: 5: 2

70.9 ± 7.4 11: 29 22: 12: 6

0.194a 0.325b 0.586b

ANOVA. Fisher's exact test.

Please cite this article as: Hori Y et al., Does sagittal imbalance impact the surgical outcomes of short-segment fusion for lumbar spinal stenosis associated with degenerative lumbar scoliosis?, Journal of Orthopaedic Science, https://doi.org/10.1016/j.jos.2018.10.005

Y. Hori et al. / Journal of Orthopaedic Science xxx (xxxx) xxx

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Fig. 1. Box plots of preoperative (preO) Cobb angle (Cobb), pelvic incidence (PI) e lumbar lordosis (LL), pelvic tilt (PT), sagittal vertical axis (SVA), and T1 pelvic angle (TPA) of the three groups divided by improvement rate in JOA score.

Fig. 2. Box plots of Cobb angle (Cobb), pelvic incidence (PI) e lumbar lordosis (LL), pelvic tilt (PT), sagittal vertical axis (SVA), and T1 pelvic angle (TPA) at final follow-up (FFU) of the three groups divided by improvement rate in JOA score.

(34.0 ± 11.9; 24.9 ± 21.4; 19.5 ± 15.0, P ¼ 0.004), SVA (82.4 ± 46.8; 81.6 ± 58.6; 38.9 ± 40.1, P ¼ 0.001), and TPA (33.4 ± 7.6; 31.6 ± 16.4; 25.1 ± 10.9, P ¼ 0.007), while there were no significant trends in Cobb angle (16.6 ± 10.4; 15.1 ± 10.5; 14.0 ± 7.7, P ¼ 0.61) or PT (33.5 ± 8.1; 30.1 ± 13.1; 29.0 ± 10.5, P ¼ 0.15). The LBP-VAS of the three groups showed a significant trend only at final follow-up (58.5 ± 31.6; 58.2 ± 35.7; 30.1 ± 23.8, P ¼ 0.001), which is shown in Fig. 3. There was no significant trend in preoperative LBP-VAS (56.1 ± 28.3; 70.8 ± 27.1; 56.7 ± 30.1, P ¼ 0.90). Using multiple linear regression analysis after adjusting for age and gender, improvement in JOAs was significantly correlated with preoperative PI-LL (P ¼ 0.007), SVA (P ¼ 0.005), and TPA (P ¼ 0.024). It also had significant correlations with PI-LL (P < 0.001), PT (P ¼ 0.031), SVA (P < 0.001), and TPA (P < 0.001) at final follow-up (Table 2). Additional surgeries were required in 12 patients (17.2%), with 10 being placed into the poor and 2 being placed into the fair outcome group. Their disease etiologies were as follows: 7 patients had adjacent segment disease (ASD), 2 had pseudoarthrosis, 1 had a vertebral fracture, and 2 had progression of the spinal deformity. As additional surgery, 9 patients underwent additional fusion, 1 underwent additional decompression, and 2 underwent corrective surgery in average 3.2 years after the first procedure.

Fig. 3. Box plots of low back pain VAS (LBP-VAS) preoperatively (preO) and at final follow-up (FFU) of the three groups divided by improvement rate in JOA score.

Please cite this article as: Hori Y et al., Does sagittal imbalance impact the surgical outcomes of short-segment fusion for lumbar spinal stenosis associated with degenerative lumbar scoliosis?, Journal of Orthopaedic Science, https://doi.org/10.1016/j.jos.2018.10.005

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Table 2 Association of improvement in JOA score with spinal parameters using multiple linear regression. Parameters

PI-LL Age Sex PT Age Sex SVA Age Sex TPA Age Sex Cobb angle Age Sex

Preoperative

Final follow up

P Value (b)

P Value (b)

0.007 0.309 0.523 0.248 0.491 0.696 0.005 0.246 0.981 0.024 0.306 0.603 0.362 0.621 0.835

<0.001 (0.007) 0.348 (0.004) 0.464 (0.053) 0.031 (0.007) 0.501 (0.003) 0.453 (0.060) <0.001 (0.003) 0.105 (0.006) 0.989 (0.001) <0.001 (0.010) 0.224 (0.005) 0.400 (0.062) 0.155 (0.006) 0.470 (0.003) 0.896 (0.010)

(0.007) (0.004) (0.049) (0.004) (0.003) (0.032) (0.002) (0.005) (0.018) (0.008) (0.004) (0.040) (0.004) (0.002) (0.016)

PI: pelvic incidence; PT: pelvic tilt; SVA: sagittal vertical axis; TPA: T1 pelvic angle. Each parameter was adjusted for age and sex. b: regression coefficient.

3.1. Case presentation Case 1: A 76-year-old woman complained of intermittent claudication with bilateral leg pain and numbness. Preoperative radiographs showed degenerative lumbar scoliosis and L4 spondylolisthesis, but good spinopelvic alignment and sagittal global balance (Fig. 4A). We diagnosed L4/5 spinal stenosis and segmental instability caused her symptoms and performed TLIF at L4-5. Three years after surgery, radiographs showed good spinal alignment and balance. Sagittal key parameters (PreO/FFU) were following; SVA:9/9 mm, PI-LL:2/5 , PT:12/23 , and TPA:9/16 .JOAs improved from 11 to 27. Case 2: A 77-year-old woman with degenerative lumbar scoliosis complained of left leg pain due to foraminal stenosis at L5-S1 on left side. Preoperative radiographs showed that PI-LL mismatch was calculated to 24 , but that sagittal balance was compensated by pelvic retroversion (Fig. 5A). Her left leg pain disappeared after TLIF at L5-S1, however sagittal imbalance deteriorated (Fig. 5B) two years after first procedure. The sagittal key parameters (PreO/FFU) changed significantly after first procedure; PI-LL:24/28 , PT:29/40 ,

SVA:43/129 mm, and TPA:25/41.Although JOAs was slightly improved from 15 to 18, LBP had got worse with sagittal imbalance. She underwent corrective surgery form T10 to pelvis (Fig. 5C). 4. Discussion Several studies have assessed the clinical outcomes of various forms of surgical treatment of DLS. Despite the publication of comparative studies and meta-analyses about the surgical treatment of DLS patients [1,10,17,22], there is no definitive surgical strategy because the circumstances surrounding each patient are highly complex. Some reports have been reported that SSF can provide adequate clinical and radiographical improvement for DLS patients. A recent meta-analysis of the surgical treatments for DLS patients by Wang et al. demonstrated that patients who underwent SSF showed a 0e44% improvement in mean ODI (Oswestry Disability Index) score and a 0e52% improvement in Cobb angle [1]. Kleinstueck et al. [10] examined 53 DLS patients who underwent SSF and reported that the COMI (Core Outcome Measurement Index) score improved by 3.1 points after surgery. Faldini et al. [22] evaluated 57 DLS patients treated with SSF and reported an improvement in RMDQ (RolandeMorris Disability Index) from 15 points to 4 points and in Cobb angle from 24 to 12 . The reoperation rate was reported to be between 15 and 33%, including revision surgery for sagittal balance correction [10,19,23,24]. We evaluated the surgical outcomes of SSF for DLS patients and also analysed the radiographic parameters that impacted surgical outcomes. In the current study, the improvement in JOA score was 52.2%, and 12 patients (17.2%) required additional surgery. As well as the previous reports, SSF for DLS patients led to clinical improvement and an acceptable rate of additional surgery. Our analysis revealed that the patients with poorer clinical outcomes had a significant trend to present with larger PI-LL, SVA, and TPA both preoperatively and at final follow-up. Additionally, the patients with poorer outcome complained of greater LBP at final follow-up, while there was no trend preoperatively. On the other hand, the coronal Cobb angle did not affect clinical results, although this series included few patients with a Cobb angle that exceeded 40 . These results indicate that LBP due to sagittal imbalance and spinopelvic malalignment may lead to poor surgical outcomes following SSF for DLS patients. Several reports have indicated that

Fig. 4. A) This 76-year-old woman complained of intermittent claudication. Preoperative radiographic parameters were following; Cobb angle:26 , PI-LL:2 , PT:12 , SVA:9 mm, and TPA:9 . B) Her symptom disappeared after TLIF at L4-5. Radiographic parameters at final follow up were following; Cobb angle:16 , PI-LL:5 , PT:23 , SVA:9 mm, and TPA:16 .

Please cite this article as: Hori Y et al., Does sagittal imbalance impact the surgical outcomes of short-segment fusion for lumbar spinal stenosis associated with degenerative lumbar scoliosis?, Journal of Orthopaedic Science, https://doi.org/10.1016/j.jos.2018.10.005

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Fig. 5. A) This 77-year-old woman complained of left leg pain due to foraminal stenosis at L5-S1. Preoperative radiographic parameters were following; Cobb angle:17, PI-LL:24 , PT:29 , SVA:43 mm, and TPA: 25 . B) She underwent TLIF at L5-S1, however sagittal imbalance progressed after the first surgery. Radiographic parameters before revision surgery was as follows; Cobb angle:28 , PI-LL:40 , PT:36 , SVA:129 mm, and TPA:41. C) Corrective surgery from T10 to pelvis was performed two years after first procedure. Sagittal key parameters improved after revision surgery; Cobb angle:12 , PI-LL:1, PT:23 , SVA:29 mm, and TPA:18 .

sagittal imbalance due to spinopelvic malalignment causes poor health-related quality of life due to LBP [25,26]. Therefore, we must understand as spinal surgeons that when we perform SSF for DLS patients with mild sagittal imbalance, some patients may need additional corrective surgery. However, corrective surgery with long instrumentation has been associated with a substantial number of perioperative and postoperative complications [27e29]. Regarding the etiology of additional surgery, corrective surgery with long instrumentation was necessary for only two patients in this series. Additionally, Kasliwal et al. reported that patients with adult scoliosis and a history of short-segment spine surgery who later underwent more extensive scoliosis correction did not appear to have significantly different complication rates or clinical improvements as compared with patients who had not had prior short-segment surgery [30]. Therefore, we recommend SSF as opposed to major corrective surgery for DLS patients with a chief complaint of leg pain and neurogenic claudication. There were some limitations to our study. First, we had no control group and our patients only had a short-term follow-up period. Future work should compare outcomes between a decompression surgery group and a corrective surgery group, and also have a longer follow-up period. Second, two out of 12 patients who underwent re-operation were placed into the fair group following the improvement of JOA scores. However, comparative analysis of the three groups could demonstrate significant trend of some radiographic parameters, and multivariate linear regression analysis supported these results. Third, we evaluated only the radiographic parameters as possible factors which impacted the clinical outcomes of SSF for the DLS patients. Other potential factors such as, duration of symptoms, life style, or atrophy of back muscles should be assessed in the further study. In spite of these limitations, our data indicated that sagittal spinal imbalance and spinopelvic malalignment significantly impacted the clinical outcomes following SSF for the DLS patients, which had been rarely reported. In the current study, we showed that SSF for DLS patients can provide clinical improvement and an acceptable rate of additional surgery. However, sagittal spinal imbalance and spinopelvic malalignment significantly impact the surgical outcomes following SSF for DLS. Preoperative evaluation of spinopelvic alignment and sagittal balance is of critical importance when SSF is performed for DLS patients.

Conflicts of interest The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. The Manuscript submitted does not contain information about medical device(s)/drug(s). Acknowledgements We thank Peter Mittwede, MD, PhD, from Edanz Group (www. edanzediting.com/ac) for editing a draft of this manuscript. References [1] Wang G, Hu J, Liu X, Cao Y. Surgical treatments for degenerative lumbar scoliosis: a meta analysis. Eur Spine J 2015 August;24(8):1792e9. [2] Ploumis A, Transfledt EE, Denis F. Degenerative lumbar scoliosis associated with spinal stenosis. Spine J 2007 July;7(4):428e36. [3] Aebi M. The adult scoliosis. Eur Spine J 2005 December;14(10):925e48. [4] Schwab F, Dubey A, Pagala M, Gamez L, Farcy JP. Adult scoliosis: a health assessment analysis by SF-36. Spine (Phila Pa 1976) 2003 March;28(6):602e6. [5] Urrutia J, Diaz-Ledezma C, Espinosa J, Berven SH. Lumbar scoliosis in postmenopausal women: prevalence and relationship with bone density, age, and body mass index. Spine (Phila Pa 1976) 2011 April;36(9):737e40. [6] Kebaish KM, Neubauer PR, Voros GD, Khoshnevisan MA, Skolasky RL. Scoliosis in adults aged forty years and older: prevalence and relationship to age, race, and gender. Spine (Phila Pa 1976) 2011 April;36(9):731e6. [7] Koerner JD, Reitman CA, Arnold PM, Rihn J. Degenerative lumbar scoliosis. JBJS Rev 2015 April;3(4):1e10. [8] Kotwal S, Pumberger M, Hughes A, Girardi F. Degenerative scoliosis: a review. Muscloskelet J Hosp Spl Surg 2011 Octorber;7(3):257e64. [9] Glassman SD, Bridwell K, Dimar JR, Horton W, Berven S, Schwab F. The impact of positive sagittal balance in adult spinal deformity. Spine (Phila Pa 1976) 2005 September;30(18):2024e9. [10] Kleinstueck FS, Fekete TF, Jeszenszky D, Haschtmann D, Mannion AF. Adult degenerative scoliosis: comparison of patient-rated outcome after three different surgical treatments. Eur Spine J 2016 August;25(8):2649e56. [11] Tribus CB. Degenerative lumbar scoliosis: evaluation and management. J Am Acad Orthop Surg 2003 May-January;11(3):174e83. [12] Gupta MC. Degenerative scoliosis. Options for surgical management. Orthop Clin N Am 2003 April;34(2):269e79. [13] Heary RF, Kumar S, Bono CM. Decision making in adult deformity. Neurosurgery 2008 September;63(3 Suppl):69e77. [14] Yadla S, Maltenfort MG, Ratliff JK, Harrop JS. Adult scoliosis surgery outcomes: a systematic review. Neurosurg Focus 2010 March;28(3):E3. [15] Youssef JA, Orndorff DO, Patty CA, Scott MA, Price HL, Hamlin LF, Williams TL, Uribe JS, Deviren V. Current status of adult spinal deformity. Global Spine J 2013 March;3(1):51e62.

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Please cite this article as: Hori Y et al., Does sagittal imbalance impact the surgical outcomes of short-segment fusion for lumbar spinal stenosis associated with degenerative lumbar scoliosis?, Journal of Orthopaedic Science, https://doi.org/10.1016/j.jos.2018.10.005