Effects of the difference between lumbar lordosis in the supine and standing positions on the clinical outcomes of decompression surgery for lumbar spinal stenosis

Shiho Nakano Department of Orthopaedic Surgery, Eastern Chiba Medical Center, Togane;

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Masahiro Inoue Department of Orthopaedic Surgery, Eastern Chiba Medical Center, Togane;

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Hiroshi Takahashi Department of Orthopaedic Surgery, University of Tsukuba;

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Go Kubota Department of Orthopaedic Surgery, Chiba Prefectural Sawara Hospital, Katori;

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Junya Saito Department of Orthopaedic Surgery, Toho University Medical Center Sakura Hospital, Sakura; and

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Masaki Norimoto Department of Orthopaedic Surgery, Toho University Medical Center Sakura Hospital, Sakura; and

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Keita Koyama Department of Orthopaedic Surgery, Toho University Medical Center Sakura Hospital, Sakura; and

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Atsuya Watanabe Department of Orthopaedic Surgery, Eastern Chiba Medical Center, Togane;

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Takayuki Nakajima Department of Orthopaedic Surgery, Eastern Chiba Medical Center, Togane;

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Yusuke Sato Department of Orthopaedic Surgery, Eastern Chiba Medical Center, Togane;

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Shuhei Ohyama Department of Orthopaedic Surgery, Eastern Chiba Medical Center, Togane;

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Sumihisa Orita Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan

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Yawara Eguchi Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan

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Kazuhide Inage Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan

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Yasuhiro Shiga Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan

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Masato Sonobe Department of Orthopaedic Surgery, Toho University Medical Center Sakura Hospital, Sakura; and

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Arata Nakajima Department of Orthopaedic Surgery, Toho University Medical Center Sakura Hospital, Sakura; and

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Seiji Ohtori Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan

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Koichi Nakagawa Department of Orthopaedic Surgery, Toho University Medical Center Sakura Hospital, Sakura; and

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Yasuchika Aoki Department of Orthopaedic Surgery, Eastern Chiba Medical Center, Togane;

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OBJECTIVE

The authors sought to evaluate the relationship between the difference in lumbar lordosis (DiLL) in the preoperative supine and standing positions and spinal sagittal alignment in patients with lumbar spinal stenosis (LSS) and to determine whether this difference affects the clinical outcome of laminectomy.

METHODS

Sixty patients who underwent single-level unilateral laminectomy for bilateral decompression of LSS were evaluated. Spinopelvic parameters in the supine and standing positions were measured preoperatively and at 3 months and 2 years postoperatively. DiLL between the supine and standing positions was determined as follows: DiLL = supine LL − standing LL. On the basis of this determination patients were then categorized into DiLL(+) and DiLL(−) groups. The relationship between DiLL and preoperative spinopelvic parameters was evaluated using Pearson’s correlation coefficient. In addition, clinical outcomes such as visual analog scale (VAS) and Oswestry Disability Index (ODI) scores between the two groups were measured, and their relationship to DiLL was evaluated using two-group comparison and multivariate analysis.

RESULTS

There were 31 patients in the DiLL(+) group and 29 in the DiLL(−) group. DiLL was not associated with supine LL but was strongly correlated with standing LL and pelvic incidence (PI) − LL (PI − LL). In the preoperative spinopelvic alignment, LL and SS in the standing position were significantly smaller in the DiLL(+) group than in the DiLL(−) group, and PI − LL was significantly higher in the DiLL(+) group than in the DiLL(−) group. There was no difference in the clinical outcomes 3 months postoperatively, but low-back pain, especially in the sitting position, was significantly higher in the DiLL(+) group 2 years postoperatively. DiLL was associated with low-back pain in the sitting position, which was likely to persist in the DiLL(+) group postoperatively.

CONCLUSIONS

We evaluated the relationship between DiLL and spinal sagittal alignment and the influence of DiLL on postoperative outcomes in patients with LSS. DiLL was strongly correlated with PI − LL, and in the DiLL(+) group, postoperative low-back pain relapsed. DiLL can be useful as a new spinal alignment evaluation method that supports the conventional spinal sagittal alignment evaluation.

ABBREVIATIONS

DiLL = difference in LL; JOABPEQ = Japanese Orthopaedic Association Back Pain Evaluation Questionnaire; LL = lumbar lordosis; LSS = lumbar spinal stenosis; ODI = Oswestry Disability Index; PI = pelvic incidence; SS = sacral slope; VAS = visual analog scale.

OBJECTIVE

The authors sought to evaluate the relationship between the difference in lumbar lordosis (DiLL) in the preoperative supine and standing positions and spinal sagittal alignment in patients with lumbar spinal stenosis (LSS) and to determine whether this difference affects the clinical outcome of laminectomy.

METHODS

Sixty patients who underwent single-level unilateral laminectomy for bilateral decompression of LSS were evaluated. Spinopelvic parameters in the supine and standing positions were measured preoperatively and at 3 months and 2 years postoperatively. DiLL between the supine and standing positions was determined as follows: DiLL = supine LL − standing LL. On the basis of this determination patients were then categorized into DiLL(+) and DiLL(−) groups. The relationship between DiLL and preoperative spinopelvic parameters was evaluated using Pearson’s correlation coefficient. In addition, clinical outcomes such as visual analog scale (VAS) and Oswestry Disability Index (ODI) scores between the two groups were measured, and their relationship to DiLL was evaluated using two-group comparison and multivariate analysis.

RESULTS

There were 31 patients in the DiLL(+) group and 29 in the DiLL(−) group. DiLL was not associated with supine LL but was strongly correlated with standing LL and pelvic incidence (PI) − LL (PI − LL). In the preoperative spinopelvic alignment, LL and SS in the standing position were significantly smaller in the DiLL(+) group than in the DiLL(−) group, and PI − LL was significantly higher in the DiLL(+) group than in the DiLL(−) group. There was no difference in the clinical outcomes 3 months postoperatively, but low-back pain, especially in the sitting position, was significantly higher in the DiLL(+) group 2 years postoperatively. DiLL was associated with low-back pain in the sitting position, which was likely to persist in the DiLL(+) group postoperatively.

CONCLUSIONS

We evaluated the relationship between DiLL and spinal sagittal alignment and the influence of DiLL on postoperative outcomes in patients with LSS. DiLL was strongly correlated with PI − LL, and in the DiLL(+) group, postoperative low-back pain relapsed. DiLL can be useful as a new spinal alignment evaluation method that supports the conventional spinal sagittal alignment evaluation.

In Brief

The authors evaluated the relationship between the difference in lumbar lordosis (DiLL) in the preoperative supine and standing positions and spinal sagittal alignment and determined whether this difference affected postoperative clinical outcomes in patients with lumbar spinal stenosis. DiLL was strongly correlated with spinal sagittal alignment, and in the DiLL(+) group, postoperative low-back pain relapsed. DiLL can be useful as a new spinal alignment evaluation method that supports the conventional method for spinal sagittal alignment evaluation.

Lumbar spinal stenosis (LSS) causes low-back pain, lower limb pain, and bladder and bowel dysfunction and is common among middle-aged and older individuals. This pathological state can sometimes hinder daily activities, requiring operative as well as conservative treatments. Low-back pain associated with LSS is often improved by decompression surgery.1,2 However, postoperative low-back pain may persist in patients with severe low-back pain before surgery or spinal deformities.3,4

The relationship between low-back pain and spinal sagittal imbalance in patients with lumbar degenerative diseases is widely recognized. The compensatory mechanisms of spinal sagittal imbalance mainly include a loss of lumbar lordosis (LL) and an increase in thoracic kyphosis and pelvic tilt. Trunk muscles play an important role in maintaining the coronal and sagittal balance of the spine.5 Surgery in patients with spinal sagittal imbalance is generally a fusion surgery. However, in cases of kyphosis due to radicular pain, decompression surgery may improve LL, but the surgical procedure is controversial.6

It has been reported that spinopelvic alignment changes with posture. LL refers to the spinal sagittal alignment, and sacral slope (SS) refers to the pelvic sagittal alignment. In healthy subjects, LL and SS are the largest in the standing position, followed by the supine position, and the smallest in the sitting position.7,8 In contrast, pelvic incidence (PI) does not change with posture.9 However, some patients with lumbar degenerative diseases demonstrate atypical changes between LL in the standing and supine positions.10,11

Regarding the effect on the surgical outcome of the difference in LL (DiLL) due to changes in postures, we have previously reported that DiLL differences between preoperative standing and supine positions affected the postoperative outcomes in patients who had undergone transforaminal lumbar interbody fusion.12,13 However, the relationship between DiLL in the standing and supine positions and spinal sagittal alignment, especially spinal sagittal imbalance, is unknown. In addition, the effect of DiLL on the results of decompression for LSS has not yet been reported. The current study is to our knowledge the first to evaluate the clinical outcomes of LSS using DiLL. The purpose of this study was to evaluate the relationship between DiLL in the preoperative standing and supine positions and the spinal sagittal alignment in patients with LSS and to determine whether it affected the clinical outcomes of laminectomy.

Methods

Patients

The study reported here was a retrospective review of prospectively collected surgical data. We retrospectively reviewed the records of 70 patients diagnosed with LSS who had consecutively undergone single-level unilateral laminectomy for bilateral decompression at our hospital from June 2010 to May 2018. The inclusion criteria were as follows: 1) patients who received no additional decompression surgery on any other level of the lumbar spine and 2) patients who completed at least a 2-year follow-up. The exclusion criteria were as follows: 1) patients who showed an indication of other pathological conditions, such as influence of infectious disease, malignant neoplasm, ankylosing spondylitis, or significant trauma; 2) patients with diseases that affected their activities of daily living; 3) patients for whom data were not available for all the evaluation items, such as questionnaires and radiographs; or 4) patients who required reoperation on their lumbar spine within 2 years after the initial surgery. Consequently, 1 patient who underwent reoperation, 6 patients with incomplete data, and 3 patients who were hospitalized due to another illness were excluded. Finally, 60 patients (42 males and 18 females) were included in the present study. Their mean age was 70.2 ± 9.7 years. This study was approved by the ethics committee of the Eastern Chiba Medical Center, Togane, Japan. All patients were informed of the purpose of the study, received information about the study, and provided consent for its publication.

Surgical Procedure

All operative procedures were performed under a surgical microscope while the patient was under general anesthesia and placed in a prone position.2,14 The interlaminar spaces of the approached side were exposed with the dissection of the paraspinal muscles from the midline. Hemilaminectomy of the approached side was performed using a high-speed burr and an osteotome. Decompression was then performed on the contralateral side, with the surgical microscope being angled on the opposite side. The spinous process and supraspinous and interspinous ligaments were preserved using this procedure, and there was little effect on spinal alignment due to surgical techniques.15 The more symptomatic side was chosen as the approach side, and if the symptoms were similar on both sides, the left-side approach was chosen.

Radiographic Evaluation

Spinopelvic parameters, such as LL, SS, and PI, were measured using preoperative radiographs taken in the standing position. In addition, LL and SS were measured using preoperative sagittal reconstruction CT images taken in the supine position. The spinopelvic alignment in the standing position was measured preoperatively and at 3 months and 2 years postoperatively, whereas the supine position was only measured preoperatively. In the current study, to evaluate the effect of DiLL in the supine and standing positions on the clinical outcomes, DiLL was calculated using the following formula: DiLL = supine LL − standing LL.

According to the positive or negative results of DiLL, we divided the patients into two groups: 1) a DiLL(+) group, comprising cases wherein the supine LL was larger than the standing LL, and a DiLL(−) group, comprising cases in which there was either no difference between the supine and standing LL or the supine LL was smaller than the standing LL (Fig. 1). Clinically, DiLL(−) is considered the normal postural change of LL (increased LL in the standing position). In addition, we evaluated cases of postoperative spondylolisthesis and disc degeneration of the lower lumbar spine.16

FIG. 1.
FIG. 1.

Sagittal CT images in the supine position (left) and radiographs in the standing position (right) in a patient in the DiLL(+) and a patient in the DiLL(−) group. The angle between the white lines indicates LL. Cases with angle (A) > (B) are DiLL(+) and those with angle (C) < (D) are DiLL(−).

Clinical Outcome

Changes in clinical symptoms were evaluated using the following methods: 1) the visual analog scale (VAS) for low-back pain, lower limb pain, and lower limb numbness, with scores ranging from 0 mm (no pain) to 100 mm (extreme pain); 2) the Oswestry Disability Index (ODI; 0–100 points); 3) the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), which includes 25 items based on the SF-36 and Roland-Morris Disability Questionnaire;17,18 and 4) our originally developed, detailed VAS scoring system for low-back pain in motion and in the standing and sitting positions.19 Clinical outcomes were evaluated preoperatively and at 3 months and 2 years postoperatively.

Statistical Analysis

Correlations between DiLL and preoperative sagittal alignment were first analyzed using Pearson’s correlation coefficient. Next, a comparative study was conducted between the DiLL(+) and DiLL(−) groups. Demographic data, sagittal alignment, and clinical outcomes were compared using the Wilcoxon rank-sum test and independent t-test, depending on whether the measured data followed a normal distribution at each time point (preoperatively, 3 months postoperatively, and 2 years postoperatively). Categorical variables were presented as a frequency (%) and compared using Pearson’s chi-square and Fisher’s exact tests. To assess the association between DiLL and postoperative residual symptoms, the influence of preoperative factors on postoperative residual symptoms was evaluated using the multiple regression analysis. The symptoms that differed between the two groups at 2 years postoperatively were used as dependent variables and age, sex, body mass index (BMI), intervertebral disc level, and DiLL were used as independent variables. Furthermore, changes in the VAS scores for low-back pain in both groups, from the preoperative period to 2 years postoperatively, were evaluated using the Steel-Dwass test. All data were reported as mean ± standard deviation unless otherwise indicated. The significance level was defined at 5%, and JMP 13 software (SAS Institute) was used for all statistical analyses in this study. The study was approved by the ethics committee of Eastern Chiba Medical Center, Togane, Japan.

Results

The correlations between DiLL and supine LL, standing LL, and PI − LL are shown in Fig. 2. DiLL was not correlated with supine LL but was strongly correlated with standing LL and PI − LL. Most of the cases with PI − LL > 10, which was considered to be spinal sagittal imbalance, were DiLL(+).

FIG. 2.
FIG. 2.

Graph showing the correlation between supine LL, standing LL, PI − LL, and DiLL. Supine LL and DiLL were not correlated, but standing LL, PI − LL, and DiLL were strongly correlated.

Of the 60 patients we examined, 31 (20 males and 11 females) were DiLL(+) and 29 (22 males and 7 females) were DiLL(−). The demographic data are shown in Table 1. The mean age was 71.0 ± 9.7 years in the DiLL(+) group and 69.3 ± 9.9 years in the DiLL(−) group, showing no significant difference. In contrast, the mean BMI of the DiLL(+) group (26.3 ± 4.1) was significantly higher than that of the DiLL(−) group (24.2 ± 3.9). In the surgical intervertebral space, L45 was the most common in 21 cases with DiLL(+) and 22 cases with DiLL(−). There was only 1 case with L5–S1 in the DiLL(+) group.

TABLE 1.

Preoperative comparison between the two groups

DiLL(+)DiLL(−)p Value
Demographic data
No. of patients3129
Age, yrs71.0 ± 9.769.3 ± 9.90.516
Sex, male/female20:1122:70.340
BMI, kg/m226.3 ± 4.124.2 ± 3.90.048
Intervertebral disc level
L2–3 21
L3–476
L4–52122
L5–S110
Sagittal alignment
Supine LL36.4 ± 10.441.3 ± 10.80.077
Supine SS32.5 ± 7.935.8 ± 7.90.111
Standing LL29.4 ± 11.846.7 ± 11.1<0.001
Standing SS25.5 ± 8.034.1 ± 7.6<0.001
Standing PI46.6 ± 8.249.8 ± 8.70.151
Standing PI − LL17.2 ± 11.83.1 ± 9.7<0.001
Questionnaire
JOABPEQ score
Pain-related disorder36.6 ± 30.658.1 ± 36.40.023
Lumbar spine dysfunction46.6 ± 27.358.9 ± 31.80.089
Gait disturbance16.1 ± 16.438.3 ± 28.40.004
Social life dysfunction30.9 ± 15.240.6 ± 19.20.019
Psychological disorder41.2 ± 18.945.5 ± 14.40.681
ODI score48.2 ± 14.636.6 ± 18.80.009
VAS score
Low-back pain5.5 ± 2.94.5 ± 3.50.275
Lower limb pain7.0 ± 2.56.8 ± 2.80.956
Lower limb numbness6.8 ± 2.56.7 ± 2.70.862
Motion pain5.7 ± 2.94.5 ± 3.00.157
Standing pain7.0 ± 2.35.2 ± 3.50.049
Sitting pain4.7 ± 5.73.9 ± 3.10.293

Values are presented as number of patients or mean ± SD unless otherwise indicated.

In preoperative spinopelvic alignment, LL and SS in the standing position were significantly smaller in the DiLL(+) group than in the DiLL(−) group, and PI − LL was significantly higher in the DiLL(+) group than in the DiLL(−) group. In the patient-based outcome score, pain-related disorder, gait disturbance, and social life dysfunction in JOABPEQ were significantly lower in the DiLL(+) group than in the DiLL(−) group, whereas low-back pain in the standing position and ODI scores were significantly higher in the DiLL(+) group than in the DiLL(−) group. Therefore, the quality of life was poor in the DiLL(+) group.

At 3 months postoperatively, there was a significant difference in LL and SS compared to the preoperative period, but no difference was found in the patient-based outcome. Even at 2 years postoperatively, there was a difference in LL and SS between the two groups. In addition, a significant difference was found in the scores indicating pain-related disorder and lumbar spine dysfunction in JOABPEQ, and low-back pain levels in motion and sitting position were more severe in the DiLL(+) group than in the DiLL(−) group (Table 2). Moreover, although low-back pain improved from the preoperative period, in the DiLL(+) group an exacerbation of low-back pain was indicated by the VAS score 2 years postoperatively compared with the score 3 months postoperatively (Fig. 3).

TABLE 2.

Spinopelvic alignment and clinical outcomes 3 months and 2 years postoperatively

Clinical Outcome
3 mos2 yrs
DiLL(+)DiLL(−)p ValueDiLL(+)DiLL(−)p Value
Sagittal alignment
Standing LL34.4 ± 12.647.1 ± 10.1<0.00134.6 ± 12.246.9 ± 11.8<0.001
Standing SS27.0 ± 8.733.9 ± 6.20.00227.6 ± 7.733.8 ± 7.10.002
Questionnaire
JOABPEQ score
Pain-related disorder81.5 ± 28.081.7 ± 30.10.88670.4 ± 34.690.8 ± 22.60.008
Lumbar spine dysfunction75.5 ± 25.883.6 ± 20.80.19262.5 ± 31.784.5 ± 23.60.003
Gait disturbance67.7 ± 30.370.7 ± 30.60.82960.4 ± 34.074.5 ± 31.70.100
Social life dysfunction59.4 ± 24.657.2 ± 23.40.54256.2 ± 25.465.5 ± 28.20.152
Psychological disorder56.1 ± 19.255.4 ± 18.00.61649.2 ± 21.257.1 ± 22.00.145
ODI score20.2 ± 19.220.5 ± 15.70.68727.3 ± 19.818.1 ± 16.90.071
VAS score
Low-back pain1.7 ± 2.32.1 ± 2.80.5933.5 ± 2.82.2 ± 2.40.047
Lower limb pain1.8 ± 2.23.1 ± 3.20.2123.2 ± 3.02.5 ± 3.20.222
Lower limb numbness2.7 ± 2.93.2 ± 3.20.6783.1 ± 3.12.6 ± 3.10.501
Motion pain1.7 ± 2.22.2 ± 3.00.6853.6 ± 2.91.9 ± 2.30.011
Standing pain2.4 ± 2.82.2 ± 2.90.3863.5 ± 2.92.4 ± 2.80.091
Sitting pain1.9 ± 2.31.9 ± 2.9 0.4013.0 ± 2.71.3 ± 1.90.003

Values are presented as mean ± SD unless otherwise indicated.

FIG. 3.
FIG. 3.

Differences in low-back pain between the DiLL(+) and DiLL(−) groups, from the preoperative period to 2 years postoperatively. Low back pain recurred in the DiLL(+) group.

Multivariate analysis of the relationships between preoperative factors and low-back pain in the sitting position is shown in Table 3. DiLL was associated with low-back pain in the sitting position, which was likely to persist in the DiLL(+) group postoperatively. A similar analysis was performed for low-back pain in the standing position, but no significant difference was observed. Measurement of standing LL 2 years postoperatively compared with standing LL preoperatively showed an increase of about 5° in the DiLL(+) group but little change in the DiLL(−) group. In addition, the number of cases in which an improvement of LL by 5° or more was observed 2 years postoperatively was significantly higher in the DiLL(+) group (17/31 patients) than in the DiLL(−) group (5/29 patients; p = 0.002; Fig. 4). Regarding lumbar instability before and after surgery, only 1 patient in the DiLL(−) group had lumbar slip after the surgery, and low-back pain was not related to spondylolisthesis. Compared with the DiLL(−) group, the DiLL(+) group had stronger disc degeneration of the lower lumbar spine preoperatively, and in some of these cases the degeneration progressed postoperatively (Table 4).

TABLE 3.

Multivariate analysis of the relationships between preoperative factors and low-back pain in the sitting position 2 years postoperatively

Independent VariableRegression Coefficient95% CIp ValueR2
Model0.037*0.202
Intercept00.688
Sex (female)0.307−0.392 to 1.0070.382
Age−0.006−0.085 to 0.0720.869
BMI−0.042−0.160 to 0.2450.670
Intervertebral disc level (L2–3, L3–4)−0.648−0.068 to 1.3630.075
DiLL(−)−0.793−1.469 to −0.1170.022

ANOVA of this model.

FIG. 4.
FIG. 4.

The graph shows the changes in LL 2 years postoperatively. The vertical axis shows the number of cases. In the DiLL(+) group, there were significantly more cases in which LL improved by 5° or more compared to the DiLL(−) group.

TABLE 4.

Changes in disc degeneration of the lower lumbar spine

Pfirrmann Scores
IIIIIIIVV
L4–5
DiLL(+)
Preop4216
2 yrs postop21811
DiLL(−)
Preop14222
2 yrs postop5204
L5–S1
DiLL(+)
Preop31414
2 yrs postop 21316
DiLL(−)
Preop19163
2 yrs postop 19145

Discussion

In the current study, we evaluated the effects of DiLL in the supine and standing positions on the postoperative course in patients with LSS after laminectomy. We observed that DiLL did not correlate with supine LL but strongly correlated with standing LL and PI − LL. In addition, the patient-based questionnaire scores indicating the quality of life, such as ODI scores, were significantly poor in the DiLL(+) group preoperatively. Furthermore, in the clinical course postoperatively there was no difference between the two groups at 3 months, but at 2 years the DiLL(+) group showed an exacerbation of low-back pain, especially in the sitting position.

Regarding the relationship between DiLL and sagittal alignment, DiLL was found to have a strong correlation with PI − LL, indicating an association with spinal sagittal imbalance. In the standing position, lordosis became stronger due to the influence of gravity, but its value became smaller in the DiLL(+) group. Hansen et al. reported that LL in both standing and supine positions was smaller in patients with lumbar disc degeneration than in healthy individuals.10 Moreover, Hasegawa et al. reported that patients with adult spinal deformity tend to show greater kyphotic lumbar alignment in the standing position than the supine position.20 Even in the current study, most cases with PI − LL > 10, indicating PI − LL mismatch, were classified as DiLL(+). Standing LL is structurally and functionally small due to decreased spinal mobility or spinal muscle weakness. It has been reported that the quality of life or ODI score is significantly reduced in cases of spinal sagittal imbalance, and the same results were obtained in our study.21 In the DiLL(+) group, there were cases in which LL increased significantly after surgery compared to the preoperative period. Endo et al. reported that kyphosis occurred due to pain avoidance, suggesting that some of the cases of kyphosis in the DiLL(+) group may have been due to pain avoidance. 6 In other words, many cases of DiLL(+) were due to either spinal sagittal imbalance or pain-avoidant kyphosis.

The incidence of low-back pain in the sitting position 2 years after surgery was significantly higher in the DiLL(+) group than in the DiLL(−) group. It has been reported that the low-back pain persists in the standing position after surgery in patients with PI − LL mismatch; this finding was different from that of our current study.22 In contrast, Takahashi et al. reported that low-back pain in motion improved after herniotomy in patients with lumbar disc herniation, but in the sitting position, it became severe when disc and endplate degeneration progressed after surgery.23 Regarding the evaluation of standing and sitting alignment, Sun et al. and Patwardhan et al. reported that lumbosacral fusion reduced LL in the sitting position and increased the load on the proximal adjacent intervertebral disc.24,25 In the current study, postoperative progression of disc degeneration of the lower lumbar spine occurred in both groups, and the relationship between the progression of disc degeneration and pain has not been evaluated. However, compared with the DiLL(−) group, the DiLL(+) group had stronger disc degeneration of the lower lumbar spine preoperatively. Therefore, we considered that the load on the intervertebral disc in the DiLL(+) group was larger than that in the DiLL(−) group, which resulted in low-back pain while sitting, as in cases of intervertebral disc disorders. Further investigation is required regarding the relationship between the progression of disc degeneration and low-back pain in the sitting position.

There are two limitations to the current study. First, the large number of DiLL(+) cases was due to PI − LL mismatch, and the results of the current study may be influenced by some other spinal sagittal imbalance. Second, sagittal imbalance and pain avoidance were considered as factors causing DiLL to be (+); however, this variable could not be evaluated concretely.

In the current study, we evaluated the relationship between spinal sagittal alignment and postoperative clinical outcomes using preoperative DiLL. This study is the first to our knowledge to evaluate the relationship between DiLL in the supine and standing positions and spinal sagittal imbalance and to determine the clinical outcomes of LSS using DiLL. Postoperative low-back pain, especially in the sitting position, may recur in the DiLL(+) group and require alignment correction.

Conclusions

We evaluated the effects of DiLL in the standing and supine positions of spinopelvic alignment and postoperative clinical outcomes in patients with LSS. DiLL was strongly correlated with LL and PI − LL in the standing position. In addition, the preoperative ODI score was higher in the DiLL(+) group than in the DiLL(−) group, and low-back pain in the sitting position recurred 2 years postoperatively in the DiLL(+) group. DiLL can be useful as a new alignment evaluation method that supports the conventional spinal sagittal alignment evaluation.

Acknowledgments

We gratefully acknowledge the work of all past and present members of our hospital.

Disclosures

The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

Author Contributions

Conception and design: Inoue, Ohyama, Aoki. Acquisition of data: Inoue, Takahashi, Kubota, Saito, Norimoto, Koyama, Watanabe, T Nakajima, Sato. Analysis and interpretation of data: Inoue, Nakano, Aoki. Drafting the article: Nakano. Critically revising the article: Inoue, Aoki. Reviewed submitted version of manuscript: Inoue, Ohyama, Orita, Eguchi, Inage, Shiga, Sonobe, A Nakajima, Ohtori. Approved the final version of the manuscript on behalf of all authors: Inoue. Statistical analysis: Inoue, Nakano. Study supervision: Takahashi, Watanabe, T Nakajima, Sato, Orita, Eguchi, Inage, Shiga, Sonobe, A Nakajima, Ohtori, Nakagawa, Aoki.

References

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  • 2

    Takahashi H, Aoki Y, Saito J, Nakajima A, Sonobe M, Akatsu Y, et al. Unilateral laminectomy for bilateral decompression improves low back pain while standing equally on both sides in patients with lumbar canal stenosis: analysis using a detailed visual analogue scale. BMC Musculoskelet Disord. 2019;20(1):100.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Kleinstück FS, Grob D, Lattig F, Bartanusz V, Porchet F, Jeszenszky D, et al. The influence of preoperative back pain on the outcome of lumbar decompression surgery. Spine (Phila Pa 1976).2009;34(11):11981203.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Tsutsui S, Kagotani R, Yamada H, Hashizume H, Minamide A, Nakagawa Y, et al. Can decompression surgery relieve low back pain in patients with lumbar spinal stenosis combined with degenerative lumbar scoliosis?. Eur Spine J. 2013;22(9):20102014.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Liang C, Sun J, Cui X, Jiang Z, Zhang W, Li T. Spinal sagittal imbalance in patients with lumbar disc herniation: its spinopelvic characteristics, strength changes of the spinal musculature and natural history after lumbar discectomy. BMC Musculoskelet Disord. 2016;17(1):305.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6

    Endo K, Suzuki H, Tanaka H, Kang Y, Yamamoto K. Sagittal spinal alignment in patients with lumbar disc herniation. Eur Spine J. 2010;19(3):435438.

  • 7

    Lee ES, Ko CW, Suh SW, Kumar S, Kang IK, Yang JH. The effect of age on sagittal plane profile of the lumbar spine according to standing, supine, and various sitting positions. J Orthop Surg Res. 2014;9(1):11.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Mauch F, Jung C, Huth J, Bauer G. Changes in the lumbar spine of athletes from supine to the true-standing position in magnetic resonance imaging. Spine (Phila Pa 1976).2010;35(9):10021007.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Chevillotte T, Coudert P, Cawley D, Bouloussa H, Mazas S, Boissière L, Gille O. Influence of posture on relationships between pelvic parameters and lumbar lordosis: comparison of the standing, seated, and supine positions. A preliminary study. Orthop Traumatol Surg Res. 2018;104(5):565568.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Hansen BB, Bendix T, Grindsted J, Bliddal H, Christensen R, Hansen P, et al. Effect of lumbar disc degeneration and low-back pain on the lumbar lordosis in supine and standing: a cross-sectional MRI study. Spine (Phila Pa 1976).2015;40(21):16901696.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Park SA, Kwak DS, Cho HJ, Min DU. Changes of spinopelvic parameters in different positions. Arch Orthop Trauma Surg. 2017;137(9):12231232.

  • 12

    Ohyama S, Aoki Y, Inoue M, Kubota G, Watanabe A, Nakajima T, et al. Influence of preoperative difference in lumbar lordosis between the standing and supine positions on clinical outcomes after single-level transforaminal lumbar interbody fusion: minimum 2-year follow-up. Spine (Phila Pa 1976).2021;46(16):10701080.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Ohyama S, Aoki Y, Inoue M, Nakajima T, Sato Y, Watanabe A, et al. Predictors of spontaneous restoration of lumbar lordosis after single-level transforaminal lumbar interbody fusion for degenerative lumbar diseases. Spine Surg Relat Res. Published online February 2021. doi:10.22603/ssrr.2020-0195

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Arai Y, Hirai T, Yoshii T, Sakai K, Kato T, Enomoto M, et al. A prospective comparative study of 2 minimally invasive decompression procedures for lumbar spinal canal stenosis: unilateral laminotomy for bilateral decompression (ULBD) versus muscle-preserving interlaminar decompression (MILD). Spine (Phila Pa 1976).2014;39(4):332340.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Ryu SJ, Kim IS. Interspinous implant with unilateral laminotomy for bilateral decompression of degenerative lumbar spinal stenosis in elderly patients. J Korean Neurosurg Soc. 2010;47(5):338344.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Pfirrmann CW, Metzdorf A, Zanetti M, Hodler J, Boos N. Magnetic resonance classification of lumbar intervertebral disc degeneration. Spine (Phila Pa 1976).2001;26(17):18731878.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17

    Sekiguchi M, Wakita T, Otani K, Onishi Y, Fukuhara S, Kikuchi S, Konno S. Lumbar spinal stenosis-specific symptom scale: validity and responsiveness. Spine (Phila Pa 1976).2014;39(23):E1388E1393.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18

    Eguchi Y, Suzuki M, Yamanaka H, Tamai H, Kobayashi T, Orita S, et al. Assessment of clinical symptoms in lumbar foraminal stenosis using the Japanese Orthopaedic Association back pain evaluation questionnaire. Korean J Spine. 2017;14(1):16.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Aoki Y, Sugiura S, Nakagawa K, et al. Evaluation of nonspecific low back pain using a new detailed visual analogue scale for patients in motion, standing, and sitting: characterizing nonspecific low back pain in elderly patients. Pain Res Treat. Published online November 18, 2012. 10.1155/2012/680496

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Hasegawa K, Okamoto M, Hatsushikano S, Caseiro G, Watanabe K. Difference in whole spinal alignment between supine and standing positions in patients with adult spinal deformity using a new comparison method with slot-scanning three-dimensional X-ray imager and computed tomography through digital reconstructed radiography. BMC Musculoskelet Disord. 2018;19(1):437.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21

    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;30(18):20242029.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 22

    Aoki Y, Nakajima A, Takahashi H, Sonobe M, Terajima F, Saito M, et al. Influence of pelvic incidence-lumbar lordosis mismatch on surgical outcomes of short-segment transforaminal lumbar interbody fusion. BMC Musculoskelet Disord. 2015;16(1):213.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 23

    Takahashi H, Aoki Y, Inoue M, Saito J, Nakajima A, Sonobe M, et al. Characteristics of relief and residual low back pain after discectomy in patients with lumbar disc herniation: analysis using a detailed visual analogue scale. BMC Musculoskelet Disord. 2021;22:167.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Sun Z, Zhou S, Wang W, Zou D, Li W. Differences in standing and sitting spinopelvic sagittal alignment for patients with posterior lumbar fusion: important considerations for the changes of unfused adjacent segments lordosis. BMC Musculoskelet Disord. 2020;21(1):760.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 25

    Patwardhan AG, Sielatycki JA, Havey RM, Humphreys SC, Hodges SD, Blank KR, et al. Loading of the lumbar spine during transition from standing to sitting: effect of fusion versus motion preservation at L4-L5 and L5-S1. Spine J. 2020;21(4):708719.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • Collapse
  • Expand
Illustration from Levi and Schwab (pp 653–659). Copyright Roberto Suazo. Published with permission.
  • FIG. 1.

    Sagittal CT images in the supine position (left) and radiographs in the standing position (right) in a patient in the DiLL(+) and a patient in the DiLL(−) group. The angle between the white lines indicates LL. Cases with angle (A) > (B) are DiLL(+) and those with angle (C) < (D) are DiLL(−).

  • FIG. 2.

    Graph showing the correlation between supine LL, standing LL, PI − LL, and DiLL. Supine LL and DiLL were not correlated, but standing LL, PI − LL, and DiLL were strongly correlated.

  • FIG. 3.

    Differences in low-back pain between the DiLL(+) and DiLL(−) groups, from the preoperative period to 2 years postoperatively. Low back pain recurred in the DiLL(+) group.

  • FIG. 4.

    The graph shows the changes in LL 2 years postoperatively. The vertical axis shows the number of cases. In the DiLL(+) group, there were significantly more cases in which LL improved by 5° or more compared to the DiLL(−) group.

  • 1

    Srinivas S, Paquet J, Bailey C, Nataraj A, Stratton A, Johnson M, et al. Effect of spinal decompression on back pain in lumbar spinal stenosis: a Canadian Spine Outcomes Research Network (CSORN) study. Spine J. 2019;19(6):10011008.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Takahashi H, Aoki Y, Saito J, Nakajima A, Sonobe M, Akatsu Y, et al. Unilateral laminectomy for bilateral decompression improves low back pain while standing equally on both sides in patients with lumbar canal stenosis: analysis using a detailed visual analogue scale. BMC Musculoskelet Disord. 2019;20(1):100.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Kleinstück FS, Grob D, Lattig F, Bartanusz V, Porchet F, Jeszenszky D, et al. The influence of preoperative back pain on the outcome of lumbar decompression surgery. Spine (Phila Pa 1976).2009;34(11):11981203.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Tsutsui S, Kagotani R, Yamada H, Hashizume H, Minamide A, Nakagawa Y, et al. Can decompression surgery relieve low back pain in patients with lumbar spinal stenosis combined with degenerative lumbar scoliosis?. Eur Spine J. 2013;22(9):20102014.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Liang C, Sun J, Cui X, Jiang Z, Zhang W, Li T. Spinal sagittal imbalance in patients with lumbar disc herniation: its spinopelvic characteristics, strength changes of the spinal musculature and natural history after lumbar discectomy. BMC Musculoskelet Disord. 2016;17(1):305.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6

    Endo K, Suzuki H, Tanaka H, Kang Y, Yamamoto K. Sagittal spinal alignment in patients with lumbar disc herniation. Eur Spine J. 2010;19(3):435438.

  • 7

    Lee ES, Ko CW, Suh SW, Kumar S, Kang IK, Yang JH. The effect of age on sagittal plane profile of the lumbar spine according to standing, supine, and various sitting positions. J Orthop Surg Res. 2014;9(1):11.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Mauch F, Jung C, Huth J, Bauer G. Changes in the lumbar spine of athletes from supine to the true-standing position in magnetic resonance imaging. Spine (Phila Pa 1976).2010;35(9):10021007.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Chevillotte T, Coudert P, Cawley D, Bouloussa H, Mazas S, Boissière L, Gille O. Influence of posture on relationships between pelvic parameters and lumbar lordosis: comparison of the standing, seated, and supine positions. A preliminary study. Orthop Traumatol Surg Res. 2018;104(5):565568.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Hansen BB, Bendix T, Grindsted J, Bliddal H, Christensen R, Hansen P, et al. Effect of lumbar disc degeneration and low-back pain on the lumbar lordosis in supine and standing: a cross-sectional MRI study. Spine (Phila Pa 1976).2015;40(21):16901696.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Park SA, Kwak DS, Cho HJ, Min DU. Changes of spinopelvic parameters in different positions. Arch Orthop Trauma Surg. 2017;137(9):12231232.

  • 12

    Ohyama S, Aoki Y, Inoue M, Kubota G, Watanabe A, Nakajima T, et al. Influence of preoperative difference in lumbar lordosis between the standing and supine positions on clinical outcomes after single-level transforaminal lumbar interbody fusion: minimum 2-year follow-up. Spine (Phila Pa 1976).2021;46(16):10701080.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Ohyama S, Aoki Y, Inoue M, Nakajima T, Sato Y, Watanabe A, et al. Predictors of spontaneous restoration of lumbar lordosis after single-level transforaminal lumbar interbody fusion for degenerative lumbar diseases. Spine Surg Relat Res. Published online February 2021. doi:10.22603/ssrr.2020-0195

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Arai Y, Hirai T, Yoshii T, Sakai K, Kato T, Enomoto M, et al. A prospective comparative study of 2 minimally invasive decompression procedures for lumbar spinal canal stenosis: unilateral laminotomy for bilateral decompression (ULBD) versus muscle-preserving interlaminar decompression (MILD). Spine (Phila Pa 1976).2014;39(4):332340.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Ryu SJ, Kim IS. Interspinous implant with unilateral laminotomy for bilateral decompression of degenerative lumbar spinal stenosis in elderly patients. J Korean Neurosurg Soc. 2010;47(5):338344.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Pfirrmann CW, Metzdorf A, Zanetti M, Hodler J, Boos N. Magnetic resonance classification of lumbar intervertebral disc degeneration. Spine (Phila Pa 1976).2001;26(17):18731878.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17

    Sekiguchi M, Wakita T, Otani K, Onishi Y, Fukuhara S, Kikuchi S, Konno S. Lumbar spinal stenosis-specific symptom scale: validity and responsiveness. Spine (Phila Pa 1976).2014;39(23):E1388E1393.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18

    Eguchi Y, Suzuki M, Yamanaka H, Tamai H, Kobayashi T, Orita S, et al. Assessment of clinical symptoms in lumbar foraminal stenosis using the Japanese Orthopaedic Association back pain evaluation questionnaire. Korean J Spine. 2017;14(1):16.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Aoki Y, Sugiura S, Nakagawa K, et al. Evaluation of nonspecific low back pain using a new detailed visual analogue scale for patients in motion, standing, and sitting: characterizing nonspecific low back pain in elderly patients. Pain Res Treat. Published online November 18, 2012. 10.1155/2012/680496

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Hasegawa K, Okamoto M, Hatsushikano S, Caseiro G, Watanabe K. Difference in whole spinal alignment between supine and standing positions in patients with adult spinal deformity using a new comparison method with slot-scanning three-dimensional X-ray imager and computed tomography through digital reconstructed radiography. BMC Musculoskelet Disord. 2018;19(1):437.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21

    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;30(18):20242029.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 22

    Aoki Y, Nakajima A, Takahashi H, Sonobe M, Terajima F, Saito M, et al. Influence of pelvic incidence-lumbar lordosis mismatch on surgical outcomes of short-segment transforaminal lumbar interbody fusion. BMC Musculoskelet Disord. 2015;16(1):213.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 23

    Takahashi H, Aoki Y, Inoue M, Saito J, Nakajima A, Sonobe M, et al. Characteristics of relief and residual low back pain after discectomy in patients with lumbar disc herniation: analysis using a detailed visual analogue scale. BMC Musculoskelet Disord. 2021;22:167.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Sun Z, Zhou S, Wang W, Zou D, Li W. Differences in standing and sitting spinopelvic sagittal alignment for patients with posterior lumbar fusion: important considerations for the changes of unfused adjacent segments lordosis. BMC Musculoskelet Disord. 2020;21(1):760.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 25

    Patwardhan AG, Sielatycki JA, Havey RM, Humphreys SC, Hodges SD, Blank KR, et al. Loading of the lumbar spine during transition from standing to sitting: effect of fusion versus motion preservation at L4-L5 and L5-S1. Spine J. 2020;21(4):708719.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation

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