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Original Article

Which Is More Predictive Value for Mechanical Complications: Fixed Thoracolumbar Alignment (T1 Pelvic Angle) Versus Dynamic Global Balance Parameter (Odontoid-Hip Axis Angle)

Kwang-Ryeol Kim1, Jean-Charles Le Huec2, Hyun-Jun Jang3, Sung-Hyun Noh4, Jeong-Yoon Park3, Yoon Ha5, Sung-Uk Kuh5, Dong-Kyu Chin3, Keun-Su Kim3, Byung-Ho Jin1, Yong-Eun Cho3, Kyung-Hyun Kim3orcid
Neurospine 2021;18(3):597-607.
Published online: September 30, 2021

1Department of Neurosurgery, International St. Mary’s Hospital, Catholic Kwandong University College of Medicine, Incheon, Korea

2Department of Orthopedic Surgery, Polyclinique Bordeaux Nord Aquitaine, Bordeaux, France

3Department of Neurosurgery, Spine and Spinal Cord Institute, Gangnam Severance Spine Hospital, Yonsei University College of Medicine, Seoul, Korea

4Department of Neurosurgery, Ajou University Hospital, Ajou University College of Medicine, Suwon, Korea

5Department of Neurosurgery, Spine and Spinal Cord Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea

Corresponding Author Kyung-Hyun Kim https://orcid.org/0000-0002-1338-5523 Department of Neurosurgery, Spine and Spinal Cord Institute, Gangnam Severance Spine Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul 06273, Korea Email: nskhk@yuhs.ac
• Received: April 30, 2021   • Revised: July 17, 2021   • Accepted: July 28, 2021

Copyright © 2021 by the Korean Spinal Neurosurgery Society

This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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  • Objective
    In this study, we investigate about relationship between postoperative global sagittal imbalance and occurrence of mechanical complications after adult spinal deformity (ASD) surgery. In global sagittal balance parameters, odontoid-hip axis (OD-HA) angle and T1 pelvic angle (TPA) were analyzed.
  • Methods
    Between January 2009 and December 2016, 199 consecutive patients (26 males and 173 females) with ASD underwent corrective fusion of more than 4 levels and were followed up for more than 2 years. Immediate postoperative and postoperative 2 years whole spine x-rays were checked for evaluating immediate postoperative OD-HA, TPA, and other parameters. In clinical outcomes, back and leg pain visual analogue scale, Scoliosis Research Society-22 spinal deformity questionnaire (SRS-22), Oswestry Disability Index (ODI), 36-item Short Form Health Survey (SF-36) were evaluated.
  • Results
    Based on the occurrence of mechanical complications, a comparative analysis was performed for each parameter. In univariable analysis, mechanical complications were significantly much more occurred in OD-HA abnormal group (odds ratio [OR], 3.296; p<0.001; area under the curve [AUC]=0.645). In multivariable analysis, the result was much more related (OR, 2.924; p=0.001; AUC=0.727). In contrast, there was no significant difference between normal and the occurrence of mechanical complications in TPA. In clinical outcomes (normal vs. abnormal), the differences of SRS-22 (0.88±0.73 vs. 0.68±0.64, p=0.042), ODI (-24.72±20.16 vs. -19.01±19.95, p=0.046), SF-36 physical composite score (19.33±18.55 vs. 12.90±16.73, p=0.011) were significantly improved in OD-HA normal group.
  • Conclusion
    The goal of ASD surgery is to improve patient life quality through correction. In our study, TPA was associated with spinopelvic parameter and OD-HA angle was associated with health-related quality of life and complications. OD-HA angle is predictable factor for mechanical complications after ASD surgery.
  • Keywords: Cervical deformity, Thoracolumbar deformity, Posture balance, Complication
Degenerative changes have the potential to greatly disrupt the normal curvature of the spine, leading to sagittal malalignment [1]. The interaction between deformity and compensatory mechanisms depicts the final presentation of patients with adult spinal deformity (ASD) [2]. ASD is a debilitating condition that often requires surgical correction. In case of severe deformity, surgical treatment has been shown to offer better clinical and radiological outcomes compared with nonoperative treatments [3-5].
However mechanical failure, such as proximal junctional kyphosis (PJK), proximal junctional failure (PJF), or rod fracture is one of the most common complication and have substantial incidence in ASD surgery. There were many studies to investigate about risk factors or predictive factors of mechanical failure after ASD surgery [6-11]. Among these radiologic parameters, increasing evidence implies that sagittal vertical axis (SVA) alone does not fully reflect sagittal malalignment, and global spinal pelvic alignment such as the T1 pelvic angle (TPA) assessment provides a more complete picture of the mechanisms for maintaining an upright posture [12]. Thus, TPA is one of the global tilt parameters that is not affected by posture with good parameter for showing thoracolumbar alignment. On the other hand, as Le Huec et al. [13] summarized the sagittal balance of the spine, odontoid-hip axis (OD-HA) angle includes a cervical alignment and have been proven to represent a constant global sagittal parameter which could show current patients posture according to gravity line [14].
TPA corresponds to the angle between a line connecting the center of T1 to the center of the femoral heads and the line to the center of the S1 endplate. It has been correlated with pelvic tilt (PT) and SVA, but does not account for pelvic incidence (PI) value. The TPA target value is under 14° and OD-HA angle is the angle between the vertical and the highest point of the dens connecting the center of the acetabulum [15,16]. The OD-HA angle target value is +2° to -5°. This angle takes into account the position of the cervical spine, the thoraco-lumbar spine and pelvis, and may benefit an overall analysis and assessment of the risk of PJK after ASD surgery (Fig. 1) [13,14,17].
Although both of these parameters have been proved to reflect global balance, there is little comparative study between these 2 parameters with regard to impact on mechanical complications or patients’ reported outcome.
Therefore, this study aimed to investigate which one would be a good representation of a patient’s global balance, to predict clinical outcome and the occurrence of mechanical complications after surgery for patients with ASD.
1. Patient Population
We retrospectively reviewed patients with ASD who underwent posterior spinal fusion and instrumentation in 2 centers. Inclusion criteria were as follows: (1) patients who underwent surgical corrective surgery for ASD; (2) those with at least one of the following radiologic criteria: coronal Cobb angle more than 20°, SVA more than 5 cm, PT more than 25°, and/or thoracic kyphosis (TK) more than 60°; (3) those who underwent posterior spinal fusion and instrumentation as ASD surgery for more than 4 levels; and (4) those with a follow-up period of more than 24 months. Exclusion criteria were (1) patients with ASD secondary to syndromic, autoimmune, infectious, tumor, or other pathologic conditions: (2) those who underwent ASD surgery for fewer than 4 levels; and (3) those with a follow-up period less than 24 months.
Between February 2011 and January 2018, 454 patients with ASD underwent spinal surgery in our institute. Among them, we excluded 253 patients whose follow-up period was less than 2 years, and those who were not indicated for corrective surgery for ASD or whose surgery level was 3 levels or less. Finally, 199 consecutive patients with sagittal imbalance who underwent ASD surgery were included.
The demographics of patients, such as age, sex, bone mineral density (BMD), body mass index (BMI) were also conducted. Dual-energy x-ray absorptiometry scan to measure BMD at the spine and hip.
This study was approved by each hospital’s Institutional Review Board, and all participants provided written informed consent.
2. Radiological Assessments
In order to minimize the error, our study used the radiographic measurement manual introduced by the Scoliosis Research Society for whole spine radiograph imaging. A 36-inch whole spinal anteroposterior and lateral planar radiographs were collected at a distance of 72 inches from the film. The patient was standing in a comfortable position with the knees fixed, feet shoulder-width apart, looking straight ahead, elbows bent, and the knuckles of the supraclavicular fossa bilaterally [18,19].
All radiologic evaluation of OD-HA angle and TPA were conducted at 4 weeks postoperatively. The normal value of OD-HA angle is +2° to -5°, and normal value of TPA was under 14° [13].
And whole spine anteroposterior/lateral was performed at postoperatively 2 years to evaluate mechanical complications; such as PI, sacral slope, L1-S1 lordosis (LL), PT, SVA, and PI–LL. In order to reduce the error between individual measurements, a software program called Surgimap (https://www.surgimap.com/) was used. Also, level of fusion vertebra, uppermost instrumented vertebra (UIV) and lowest instrumented vertebra (LIV), and state of spinopelvic fixation (SPF) were conducted.
3. Mechanical Complications and Clinical Outcomes
Mechanical complications were defined as PJK or PJF, distal junctional kyphosis (DJK) or distal junctional failure, rod fracture, and implant-related complications [20,21]. Implant-related complications were defined as rod breakage or prominence, painful implant, screw breakage, loosening, or malposition, implant (interbody graft, hook, or set-screw) dislodgement [20,22].
In clinical assessments, patients reported pre- and postoperative 24-month back and leg pain using a visual analogue scale (VAS) scored from 0–10. The Oswestry Disability Index (ODI), Scoliosis Research Society-22 spinal deformity questionnaire (SRS-22), and 36-item Short Form Health Survey (SF-36) were used to measure health-related quality of life (HRQoL) measures.
4. Statistical Analysis
Statistical analyses were performed using SAS 9.4 (SAS Institute Inc., Cary, NC, USA). Demographic and radiological data were compared using independent t-test and categorical variables using chi-square test or Fisher exact test. The logistic regression model is established with mechanical complications, PJK, PJF, and implant-related failure as outcome. The results are expressed as mean±standard deviation or number (percentage). A p-value less than 0.05 was considered statistically significant.
A total of 199 patients (26 males and 173 females) were retrospectively reviewed. The average age was 67.36 years (range, 49–80 years), and they were followed for an average of 30.54 months (range, 24–118 months).
Patients were classified according to normal TPA and OD-HA angle values. In the OD-HA angle group, 102 patients were in the normal range and 97 patients were in the abnormal range, In the TPA group had 59 patients with a normal range and 140 patients with an abnormal range. Although the OD-HA angle group showed no difference between normal and abnormal groups in demographic comparisons, the TPA group had a high average age and female ratio in the abnormal group. In radiological assessments, postoperative sagittal balance parameters were compared with fusion segment, UIV, LIV, and SPF via whole spine radiographs anteroposterior/lateral view for the 2 years after surgery. In postoperative parameters, in OD-HA angle groups, the normal group was on average close to normal compared to the abnormal group, but there was no statistical significance. On the other and, the TPA group showed differences in SVA, PI–LL, PI, and PT values, which were statistically significant. For instrumentation, on average, there were 7 fusion segments, T11–12 for UIV, L5–S1 for LIV. In these results, both OD-HA angle and TPA were not different in normal and abnormal groups. In SPF, 91 patients were administered and 108 were not. In this result, OD-HA angle was significantly more frequent in the normal group, and there was no difference between the 2 groups in TPA (Table 1).
In clinical assessments, back and leg VAS related to pain and ODI, SRS-22, SF-36 related to functional impairment were analyzed. First of all, there was no significant difference in pain between normal and abnormal groups in the OD-HA angle group. However, there were significant differences in the change values of ODI, SRS-22, and SF-36 physical composite score related to the functional impairment. On the other hand, in the TPA group, there was no significant difference in functional impairment between normal and abnormal groups, but in the case of pain, the results were particularly favorable in the back pain, which was statistically significant (Table 2).
A simple comparison of the patients’ mechanical complication, PJK, PJF, and implant-related complication was conducted. In the entire patient population, the incidence of complications (n, %) was mechanical complication (84 of 199, 42.2%), PJK (80 of 199, 40.2%), PJF (43 of 199, 21.6%), implant-related complication (26 of 199, 13.1%). In simple comparison, there was no difference between normal and abnormal groups in TPA, but in C2HA, there was a difference between normal and abnormal groups. [Normal (n, %) vs. abnormal (n, %), p-value, mechanical complication (29 of 102, 28.4%) vs. (55 of 97, 56.7%), p<0.001; PJK (28 of 102, 27.5%) vs. (52 of 97, 53.6%), p<0.001; PJF (13 of 102, 12.8%) vs. 30 of 97, 30.9%, p=0.002; implant-related complication (7 of 102, 6.9%) vs. 19 of 97, 19.6%, p=0.008] (Table 3).
In order to investigate the correlation more closely, a logistic regression was constructed using mechanical complication, PJK, PJF, and implant-related complication as outcomes. In univariate analysis, OD-HA angle, age, BMD, BMI, postoperative SVA was related with postoperative mechanical complication. In multivariable analysis, OD-HA angle was related with postoperative mechanical complication (OR, 2.924; p=0.001; AUC=0.727) (Table 4, Fig. 2).
Recent studies on outcomes following ASD surgeries have shown high rates of complications (8.4%–42%) and revision rates (9%–17.6%) [2,12,23-25]. In our study, the overall mechanical complication occurred in about 42%, and revision rate was about 21%. This is slightly higher than other studies, but does not show much difference [3,11,22].
The occurrence of mechanical complications after ASD surgery has already been dealt with in several studies. In previous studies, thoracoplasty, posterior spinal fusion, combined anteroposterior spinal fusion preoperative existence of more than 5° proximal junctional angle one level above UIV, fusion to the sacrum and surgical correction of TK more than 50% was suggested as risk factors for PJK [7,11,26-29]. And older age (over 55 years), large abnormal preoperative sagittal parameters, osteoporosis, high BMI, thoracoplasty, and fusion to the lower lumbar vertebra and sacrum was suggested as risk factors for PJF [12,30-33].
Yagi et al. [11] demonstrated that PJK can be minimized by postoperative normalization of global spine alignment and balance. Thus, we analyzed the difference according to whether normality of the postoperative global balance parameters TPA and OD-HA angle.
It is done through cervical curvature and lumbar lordosis in order to maintain a horizontal gaze and to free the upper limbs. It is important to analyze the problem statically and dynamically to understand the conditions required for this balance. Recently, several studies demonstrated that OD-HA angle was characterized the overall spinal balance, remains constant whatever the age and despite variations of lordosis (which decreases with loss of disc height) and the presence of compensation mechanism. And it hardly varies and is a good way to study the overall sagittal balance. It integrates the cervical spine and head and stays constant even in elderly if they are asymptomatic [13-15].
In Dubousset’s conus of economy (ref), the concept of balance includes from head to lower limbs. Therefore, the center of the head, that is, the center of C2, which is a line descending from the center of the external auditory meatus, can be regarded as the center of gravity. For that reason, OD-HA could be a good indicator of global balance in terms of the concept of Dubousset’s conus of economy that global balance is the ability of a person to stand upright with respect to gravity and that it is efficient to use the least energy. However, there are not many studies yet analyzed whether this indicator can predict mechanical complications in ASD.
Protopsaltis et al. [16] introduced about TPA, and several studies reported it is related with clinical outcomes of patients’ mechanical complication after ASD surgery [12,16,20,21,34]. TPA is similar to the spinopelvic angle, allows the patient to check thoracolumbar alignment well, and is not affected by changes in the patient’s posture, so it can be evaluated objectively. It can be assumed that there may be a downside to being difficult to know exactly in terms of the ability to stand in the Dubousset’s conus of economy. In our study, the normality of TPA was related to the normal value of the spinopelvic parameter after surgery, and was related to the pain parameters. The sagittal spinopelvic parameters were related with chronic back pain and/or HRQoL [34-36]. It can be seen that this contributed to the improvement of back pain by sufficiently making lordosis through correction of the sagittal imbalance. TPA has a certain value even in the stooping posture of the patient because the alignment of cervical spine and the horizontal gaze of the patient are missing. There was no research on whether these differences were related to the prediction of mechanical complications. In postoperative stooping posture related with global imbalance of the patient after ASD surgery, it may be due to pain, and there may be various reasons. Such as, PJK, DJK, pain, insufficient decompression. If the patient’s global balance cannot be maintained due to various reasons, assuming that the OD-HA angle might come out poorly and TPA remains constant, we studied whether this difference is different in the prediction of the patient’s postoperative prognosis, that is, the mechanical complication. Results in our paper, OD-HA angle showed better results.
In several studies have reported that spinopelvic fixation affects the occurrence of PJK. In several studies reported SPF with iliac screws had high rates of lumbosacral fusion and low incidence of mechanical complications and revision surgery for PJK [37] and reduced sacroiliac joint pain after multisegment spinal fusion after SPF with S2 alar iliac screws [38]. Otherwise, some studies reported although the rigid SPF has decreased the risk for distal screw loosening, cyclic loading during daily activities might lead to fatigue of the posterior instrumentation, which can result in mechanical long-term complications such as nonunion and eventually increase the risk of iliac screw loosening, development of PJK, PJF, and pseudarthrosis or pedicle screw loosening at L5–S1 level [10,39,40]. In our study, statistical significance was not observed, but there was a force to SPF was related with development of mechanical complication especially PJK/PJF.
Also, many articles reported that older age, osteoporosis, and obesity are important risk factors of mechanical complication, PJK, and PJF. Lau et al. [32] demonstrated that age was an important risk factor of PJK and PJF. And high BMI was related with worse sagittal alignment after ASD surgery and worse postoperative scores in HRQoL, and development of PJK [10,20,41]. And osteoporosis was related with PJK and PJF [10,11,20]. Especially, Yagi et al. [11] reported low BMD (T score < -1.5) was a significant risk factor for the incidence of PJF. In our study, older age was related with occurrence of mechanical complication, BMD was related with all types of complications, and BMI was related with occurrence of mechanical complication and PJK. Sexual difference was not related with occurrence of complications. In radiological assessments, postoperative SVA was related with occurrence of mechanical complication and PJK. The other postoperative sagittal parameters were not related with complications. And UIV and LIV were similar between the 2 groups as T11–12 and L5–S1. In SPF, there is no significant difference between the 2 groups, but it shows approaching an acceptable significance level. The results of our study were also similar to previous other studies (Table 5).
The present study had several limitations. Because this was not a randomized and prospective study, but rather retrospective in design, a control population that received standard conservative care was not included. In addition, we did not control for selected surgical method or the period of preoperative conservative management. Meanwhile, the clinical score was not an absolute result because it was entirely patent specific. The images of the patients were measured by whole spine x-ray. Due to this, there may be some correction by the patient’s position. Finally, the results of this study may be limited because it was conducted only in a single country and a single institution. Further studies are needed with multicenter, multinational, and multiracial data for more reliable results in the future.
The goal of ASD surgery is to improve patient life quality through correction. In our study, TPA was associated with spinopelvic parameter and clinical parameters related with pain, OD-HA angle was associated with clinical parameters with functional impairment and complications. OD-HA angle is predictable factor for mechanical complications after ASD surgery.

The authors have nothing to disclose.

Fig. 1.
Measurement of global balance parameters. (A) Odontoid-hip axis (OD-HA) angle. OD-HA angle (white lines) is the angle between the vertical and the hightest point of the dens connecting the center of the femoral heads (black dotted line, center of the black circles). The OD-HA angle target value is +2° to -5°. (B) T1 pelvic angle (TPA). TPA (white dotted lines) corresponds to the angle between a line connecting the center of T1 to the center of the femoral heads (black dotted line, center of the black circles) and the line to the center of the S1 endplate (black line). The TPA target value is under 14°.
ns-2142452-226f1.jpg
Fig. 2.
Receiver operating characteristic (ROC) curve. Logistic regression (mechanical complication) in odontoid-hip axis angle. Odds ratio, 2.924; p=0.001; area under the curve=0.727
ns-2142452-226f2.jpg
Table 1.
Demographic variables and radiographic data between OD-HA and TPA
Table 1.
Variable Total (n=199) OD-HA
 TPA
Normal (n=102) Abnormal (n=97) p-value Normal (n = 59) Abnormal (n=140) p-value
Demographics
 Age (yr) 67.36 ± 8.28 66.71 ± 8.23 68.052 ± 8.32 0.253 64.61 ± 8.97 68.52 ± 7.71 0.002*
 Sex 0.162 0.015†
  Male 26 (13.07) 10 (9.80) 16 (16.49) 13 (22.03) 13 (9.29)
  Female 173 (86.93) 92 (90.20) 81 (83.51) 46 (77.97) 127 (90.71)
 BMD -1.98 ± 1.05 -1.91 ± 1.03 -2.063 ± 1.07 0.299 -1.84 ± 0.85 -2.04 ± 1.12 0.170
 BMI (kg/m2) 23.98 ± 2.61 23.71 ± 2.37 24.261 ± 2.82 0.133 24.26 ± 2.85 23.86 ± 2.50 0.328
Postoperative parameters
 SVA 38.18 ± 39.98 34.73 ± 26.00 41.80 ± 50.60 0.221 26.98 ± 37.95 42.89 ± 40.01 0.010*
 PI–LL 15.81 ± 12.82 14.69 ± 11.88 16.98 ± 13.70 0.208 9.60 ± 10.44 18.43 ± 12.86 < 0.001*
 LL 35.03 ± 12.97 35.13 ± 13.43 34.92 ± 12.54 0.906 35.63 ± 11.67 34.78 ± 13.51 0.674
 PI 50.84 ± 11.91 49.82 ± 12.33 51.90 ± 11.42 0.220 45.22 ± 9.47 53.20 ± 12.07 < 0.001*
 PT 24.01 ± 9.77 23.22 ± 8.39 24.85 ± 11.02 0.243 18.19 ± 8.38 26.47 ± 9.29 < 0.001*
 SS 27.53 ± 10.39 27.65 ± 10.54 27.40 ± 10.29 0.862 27.90 ± 8.69 27.37 ± 11.06 0.718
Instrumentation
 Segments‡ 7.13 ± 2.41 6.95 ± 2.18 7.32 ± 2.62 0.282 7.12 ± 2.36 7.14 ± 2.44 0.964
 UIV§ 11.40 ± 2.54 11.69 ± 2.23 11.10 ± 2.81 0.101 11.39 ± 2.60 11.40 ± 2.52 0.980
 LIV§ 17.52 ± 1.18 17.62 ± 0.85 17.41 ± 1.44 0.225 17.51 ± 1.37 17.52 ± 1.09 0.949
 SPF 0.006† 0.529
  No 108 (54.27) 62 (60.78) 46 (47.42) 30 (50.85) 78 (55.71)
  Yes 91 (45.73) 40 (39.22) 52 (52.58) 29 (49.15) 62 (44.29)

Values are presented as mean±standard deviation or number (%).

OD-HA, odontoind-hip axis angle; TPA, T1-pelvic angle; BMD, bone mineral density; BMI, body mass index; SVA, sagittal vertical axis; PI, pelvic incidence; LL, lumbar lordosis; PT, pelvic tilt; SS, sacral slope; UIV, upper most instrumented vertebra; LIV, lower most instrumented vertebra; SPF, spino-pelvic fixation.

*p<0.05, statistically significantly differences in independent t-test.

†p<0.05, statistically significantly differences in chi-square test (Fisher exact test).

‡The number of instrumented vertebral segments.

§Numbering the spine. It starts with 1 for C1 and ends with 18 for S1. Number 11 stands for T11, and number 17 for L5.

Table 2.
Clinical data between OD-HA versus TPA
Table 2.
Variable Total (n=199) OD-HA
 TPA
Normal (n=102) Abnormal (n=97) p-value Normal (n=59) Abnormal (n=140) p-value
Back VAS
 Preoperative 7.41 ± 1.98 7.43 ± 2.02 7.38 ± 1.94 0.860 7.53 ± 1.73 7.36 ± 2.08 0.585
 Postoperative 4.73 ± 2.47 4.51 ± 2.44 4.96 ± 2.48 0.200 4.12 ± 2.39 4.99 ± 2.46 0.023*
 Changes -2.68 ± 2.23 -2.92 ± 2.29 -2.42 ± 2.15 0.115 -3.41 ± 2.20 -2.37 ± 2.18 0.003*
Leg VAS
 Preoperative 6.76 ± 2.88 7.03 ± 2.82 6.49 ± 2.93 0.183 6.48 ± 3.00 6.89 ± 2.83 0.359
 Postoperative 4.44 ± 2.90 4.40 ± 2.79 4.47 ± 3.03 0.861 3.71 ± 2.59 4.74 ± 2.98 0.022*
 Changes -2.33 ± 2.89 -2.63 ± 2.95 -2.01 ± 2.82 0.133 -2.76 ± 3.20 -2.14 ± 2.75 0.168
ODI
 Preoperative 60.02 ± 17.04 59.91 ± 15.81 60.14 ± 18.32 0.923 60.57 ± 14.77 59.79 ± 17.96 0.770
 Postoperative 38.09 ± 19.85 35.19 ± 18.40 41.13 ± 20.93 0.034* 35.07 ± 17.03 39.36 ± 20.85 0.165
 Changes -21.94 ± 20.21 -24.72 ± 20.16 -19.01 ± 19.95 0.046* -25.50 ± 17.05 -20.44 ± 21.28 0.107
SRS-22
 Preoperative 2.38 ± 0.47 2.37 ± 0.49 2.39 ± 0.45 0.762 2.38 ± 0.47 2.38 ± 0.47 0.931
 Postoperative 3.16 ± 0.72 3.25 ± 0.72 3.07 ± 0.72 0.081 3.29 ± 0.71 3.11 ± 0.72 0.120
 Changes 0.78 ± 0.69 0.88 ± 0.73 0.68 ± 0.64 0.042* 0.91 ± 0.66 0.73 ± 0.70 0.092
SF-36 PCS
 Preoperative 27.18 ± 17.95 25.44 ± 17.19 29.01 ± 18.62 0.162 27.04 ± 17.75 27.24 ± 18.10 0.943
 Postoperative 43.38 ± 21.65 44.77 ± 20.90 41.91 ± 22.44 0.354 44.96 ± 20.50 42.71 ± 22.16 0.506
 Changes 16.20 ± 17.93 19.33 ± 18.55 12.90 ± 16.73 0.011* 17.92 ± 16.22 15.47 ± 18.61 0.381
SF-36 MCS
 Preoperative 35.85 ± 18.94 34.99 ± 18.35 36.76 ± 19.59 0.512 36.42 ± 20.74 35.61 ± 18.20 0.783
 Postoperative 53.44 ± 23.28 55.02 ± 23.74 51.77 ± 22.80 0.326 54.03 ± 23.55 53.19 ± 23.25 0.818
 Changes 17.59 ± 18.61 20.04 ± 20.01 15.02 ± 16.74 0.057 17.61 ± 19.25 17.58 ± 18.41 0.993

Values are presented as mean±standard deviation.

OD-HA, odontoid-hip axis; TPA, T1-pelvic angle; VAS, visual analogue scale; ODI, Oswestry Disability Index; SRS, scoliosis research society; SF-36, 36-item Short Form Health Survey; PCS, physical component summary; MCS, mental component summary.

*p<0.05, statistically significantly differences in independent t-test.

Table 3.
Occurrence of complications between OD-HA versus TPA
Table 3.
Variable Total (n=199) OD-HA
 TPA
Normal (n=102) Abnormal (n=97) p-value Normal (n = 59) Abnormal (n = 140) p-value
Mechanical complication < 0.001* 0.123
 Occurred 84 (42.2) 29 (28.4) 55 (56.7) 20 (33.9) 64 (450.7)
 Not occurred 115 (57.8) 73 (71.6) 42 (43.3) 39 (66.1) 76 (540.3)
PJK < 0.001* 0.135
 Occurred 80 (40.2) 28 (27.5) 52 (53.6) 19 (32.2) 61 (430.6)
 Not occurred 119 (59.8) 74 (72.5) 45 (46.4) 40 (67.8) 79 (560.4)
PJF 0.002* 0.925
 Occurred 43 (21.6) 13 (12.8) 30 (300.9) 13 (22.0) 30 (210.4)
 Not occurred 156 (78.4) 89 (87.3) 67 (690.1) 46 (78.0) 110 (780.6)
Implant related complication 0.008* 0.431
 Occurred 26 (13.1) 7 (6.9) 19 (190.6) 6 (10.2) 20 (14.3)
 Not occurred 173 (86.9) 95 (93.1) 78 (80.4) 53 (89.8) 120 (85.7)

Values are presented as number (%).

OD-HA, odontoid-hip axis; TPA, T1-pelvic angle; PJK, proximal junctional kyphosis; PJF, proximal junctional failure.

*p<0.05, statistically significantly differences in chi-square test.

Table 4.
Logistic regression (mechanical complication) in OD-HA angle
Table 4.
Univariable (n = 199)
 Multivariable
OR (95% CI) p-value AUC OR (95% CI) p-value AUC
OD-HA 0.645 0.727
 Normal Reference Reference
 Abnormal 3.296 (1.830–5.938) < 0.001* 2.924 (1.567–5.455) 0.001*
TPA
 Normal Reference Reference
 Abnormal 1.642 (0.872–3.094) 0.125 1.370 (0.673–2.791) 0.386
Age 1.038 (1.000–1.077) 0.048* 1.018 (0.978–1.060) 0.390
Sex
 Female Reference
 Male 0.832 (0.363–1.904) 0.663
BMD 0.634 (0.473–0.850) 0.002* 0.739 (0.527–1.039) 0.082
BMI 1.199 (1.066–1.349) 0.003* 1.144 (1.008–1.299) 0.038*
SVA 1.009 (1.001–1.017) 0.020* 1.006 (0.997–1.014) 0.174
PI–LL 1.016 (0.994–1.039) 0.152
PI 1.005 (0.981–1.029) 0.690
LL 0.988 (0.967–1.010) 0.292
PT 1.013 (0.984–1.043) 0.381
SS 0.995 (0.968–1.022) 0.702
Fusion level segments 1.022 (0.909–1.148) 0.719
UIV 0.996 (0.891–1.113) 0.939
LIV 1.073 (0.836–1.377) 0.582
SPF
 None Reference Reference
 Done 1.731 (0.980–3.055) 0.059 1.324 (0.695–2.523) 0.393

OD-HA, odontoid-hip axis; OR, odds ratio; CI, confidence interval; AUC, area under the curve; TPA, T1 pelvic angle; BMD, bone mineral density; BMI, body mass index; PI, pelvic index; LL, lumbar lordosis; PT, pelvic tilt; SS, sacral slope; SVA, sagittal vertical axis; UIV, uppermost instrumented vertebra; LIV, lowest instrumented vertebra; SPF, spino-pelvic fixation.

*p<0.05, statistically significantly differences in logistic regression.

Table 5.
Risk factors according to occurrence of complications
Table 5.
Variable Total (n=199) Mechanical complication
 Proximal junctional kyphosis
 Proximal junctional failure
 Implant related complication
Normal (n=115) Occurred (n=84) p-value Normal (n=119) Occurred (n=80) p-value Normal (n=156) Occurred (n=43) p-value Normal (n = 173) Occurred (n = 26) p-value
Demographics
  Age 67.36 ± 8.28 66.36 ± 8.75 68.74 ± 7.42 0.045* 66.72 ± 8.45 68.31 ± 7.98 0.185 67.44 ± 8.17 67.07 ± 8.74 0.795 67.12 ± 8.18 69.00 ± 8.89 0.280
Sex 0.676 0.526 0.305 0.755
  Male 26 (13.07) 14 (12.17) 12 (14.29) 14 (11.76) 12 (15.00) 18 (11.54) 8 (18.60) 22 (12.72) 4 (15.38)
Female 173 (86.93) 101 (87.83) 72 (85.71) 105 (88.24) 68 (85.00) 138 (88.46) 35 (81.40) 151 (87.28) 22 (84.62)
BMD -1.98 ± 1.05 -1.78 ± 0.93 -2.26 ± 1.14 0.001* -1.81 ± 0.93 -2.24 ± 1.16 0.004* -1.87 ± 0.99 -2.40 ± 1.15 0.003* -1.86 ± 0.99 -2.78 ± 1.16 < 0.001*
BMI 23.98 ± 2.61 23.49 ± 2.46 24.64 ± 2.67 0.002* 23.59 ± 2.35 24.55 ± 2.87 0.011* 23.76 ± 2.35 24.75 ± 3.30 0.072 23.86 ± 2.40 24.76 ± 3.68 0.236
Postoperative parameters
SVA 38.18 ± 39.98 32.36 ± 30.77 46.14 ± 49.01 0.025* 31.44 ± 30.38 48.20 ± 49.57 0.008* 35.78 ± 34.76 46.86 ± 54.57 0.213 36.69 ± 37.36 48.07 ± 54.24 0.310
PI-LL 15.81 ± 12.82 14.69 ± 12.11 17.34 ± 13.66 0.151 15.16 ± 12.08 16.77 ± 13.87 0.386 16.17 ± 12.47 14.50 ± 14.08 0.450 15.66 ± 12.33 16.78 ± 15.97 0.734
LL 35.03 ± 12.97 35.86 ± 13.28 33.89 ± 12.52 0.293 35.81 ± 13.10 33.85 ± 12.76 0.295 34.74 ± 13.25 36.07 ± 12.01 0.554 34.43 ± 12.85 39.03 ± 13.29 0.091
PI 50.84 ± 11.91 50.55 ± 12.49 51.23 ± 11.14 0.691 50.98 ± 12.52 50.62 ± 11.01 0.836 50.91 ± 11.97 50.56 ± 11.84 0.866 50.09 ± 12.11 55.81 ± 9.24 0.022
PT 24.01 ± 9.77 23.50 ± 8.75 24.72 ± 11.03 0.382 23.97 ± 8.92 24.07 ± 10.98 0.945 24.35 ± 9.07 22.80 ± 12.01 0.358 23.78 ± 8.84 25.60 ± 14.66 0.542
SS 27.53 ± 10.39 27.77 ± 10.21 27.20 ± 10.69 0.704 27.67 ± 10.10 27.31 ± 10.87 0.809 27.28 ± 9.86 28.43 ± 12.23 0.519 27.14 ± 10.00 30.09 ± 12.64 0.178
Instrumentation
Segments† 7.13±2.41 7.08 ± 2.30 7.20 ± 2.56 0.721 7.01 ± 2.29 7.31 ± 2.58 0.384 7.03 ± 2.32 7.51 ± 2.69 0.242 7.02 ± 2.36 7.85 ± 2.63 0.104
UIV‡ 11.40 ± 2.54 11.41 ± 2.39 11.38 ± 2.75 0.940 11.51 ± 2.37 11.23 ± 2.77 0.435 11.51 ± 2.41 11.00 ± 2.94 0.248 11.53 ± 2.52 10.54 ± 2.52 0.064
LIV‡ 17.52 ± 1.18 17.48 ± 1.05 17.57 ± 1.34 0.582 17.51 ± 1.01 17.53 ± 1.40 0.942 17.53 ± 1.15 17.49 ± 1.28 0.855 17.54 ± 1.13 17.39 ± 1.44 0.538
SPF 0.063 0.081 0.084 0.210
  No 108 (54.27) 69 (60.00) 39 (46.43) 71 (59.66) 37 (46.25) 90 (57.69) 18 (41.86) 97 (56.07) 11 (42.31)
Yes 91 (45.73) 46 (40.00) 45 (53.57) 48 (40.34) 43 (53.75) 66 (42.31) 25 (58.14) 76 (43.93) 15 (57.69)

Values are presented as mean±standard deviation or number (%).

BMD, bone mineral density; BMI, body mass index; SVA, sagittal vertical axis; PI, pelvic incidence; LL, lumbar lordosis; PT, pelvic tilt; SS, sacral slope; UIV, upper most instrumented vertebra; LIV, lower most instrumented vertebra; SPF, spino-pelvic fixation.

*p<0.05, statistically significantly differences in independent t-test.

†The number of instrumented vertebral segments.

‡Numbering the spine. It starts with 1 for C1 and ends with 18 for S1. Number 11 stands for T11, and number 17 for L5.

  • 1. Barrey C, Roussouly P, Perrin G, et al. Sagittal balance disorders in severe degenerative spine. Can we identify the compensatory mechanisms? Eur Spine J 2011;20:626-33.
  • 2. Diebo BG, Henry J, Lafage V, et al. Sagittal deformities of the spine: factors influencing the outcomes and complications. Eur Spine J 2015;24 Suppl 1:S3-15.
  • 3. Barton C, Noshchenko A, Patel V, et al. Risk factors for rod fracture after posterior correction of adult spinal deformity with osteotomy: a retrospective case-series. Scoliosis 2015;10:30.
  • 4. Shapiro GS, Taira G, Boachie-Adjei O. Results of surgical treatment of adult idiopathic scoliosis with low back pain and spinal stenosis: a study of long-term clinical radiographic outcomes. Spine (Phila Pa 1976) 2003;28:358-63.
  • 5. Yamada K, Nakamae T, Shimbo T, et al. Targeted therapy for low back pain in elderly degenerative lumbar scoliosis: a cohort study. Spine (Phila Pa 1976) 2016;41:872-9.
  • 6. Glattes RC, Bridwell KH, Lenke LG, et al. Proximal junctional kyphosis in adult spinal deformity following long instrumented posterior spinal fusion: incidence, outcomes, and risk factor analysis. Spine (Phila Pa 1976) 2005;30:1643-9.
  • 7. Kim YJ, Bridwell KH, Lenke LG, et al. Proximal junctional kyphosis in adult spinal deformity after segmental posterior spinal instrumentation and fusion: minimum five-year follow-up. Spine (Phila Pa 1976) 2008;33:2179-84.
  • 8. Liu FY, Wang T, Yang SD, et al. Incidence and risk factors for proximal junctional kyphosis: a meta-analysis. Eur Spine J 2016;25:2376-83.
  • 9. Maruo K, Ha Y, Inoue S, et al. Predictive factors for proximal junctional kyphosis in long fusions to the sacrum in adult spinal deformity. Spine (Phila Pa 1976) 2013;38:E1469-76.
  • 10. Park SJ, Lee CS, Chung SS, et al. Different risk factors of proximal junctional kyphosis and proximal junctional failure following long instrumented fusion to the sacrum for adult spinal deformity: survivorship analysis of 160 patients. Neurosurgery 2017;80:279-86.
  • 11. Yagi M, Akilah KB, Boachie-Adjei O. Incidence, risk factors and classification of proximal junctional kyphosis: surgical outcomes review of adult idiopathic scoliosis. Spine (Phila Pa 1976) 2011;36:E60-8.
  • 12. Jacobs E, van Royen BJ, van Kuijk SM, et al. Prediction of mechanical complications in adult spinal deformity surgery—the GAP score versus the Schwab classification. Spine J 2019;19:781-8.
  • 13. Le Huec J, Thompson W, Mohsinaly Y, et al. Sagittal balance of the spine. Eur Spine J 2019;28:1889-905.
  • 14. Amabile C, Le Huec JC, Skalli W. Invariance of head-pelvis alignment and compensatory mechanisms for asymptomatic adults older than 49 years. Eur Spine J 2018;27:458-66.
  • 15. Amabile C, Pillet H, Lafage V, et al. A new quasi-invariant parameter characterizing the postural alignment of young asymptomatic adults. Eur Spine J 2016;25:3666-74.
  • 16. Protopsaltis T, Schwab F, Bronsard N, et al. The T1 pelvic angle, a novel radiographic measure of global sagittal deformity, accounts for both spinal inclination and pelvic tilt and correlates with health-related quality of life. J Bone Joint Surg Am 2014;96:1631-40.
  • 17. Faundez AA, Richards J, Maxy P, et al. The mechanism in junctional failure of thoraco-lumbar fusions. Part II: analysis of a series of PJK after thoraco-lumbar fusion to determine parameters allowing to predict the risk of junctional breakdown. Eur Spine J 2018;27(Suppl 1):139-48.
  • 18. Hey HWD, Lau ETC, Tan KA, et al. Lumbar spine alignment in six common postures. Spine (Phila Pa 1976) 2017;42:1447-55.
  • 19. Janssen MM, Drevelle X, Humbert L, et al. Differences in male and female spino-pelvic alignment in asymptomatic young adults: a three-dimensional analysis using upright low-dose digital biplanar X-rays. Spine (Phila Pa 1976) 2009;34:E826-32.
  • 20. Noh SH, Ha Y, Obeid I, et al. Modified global alignment and proportion scoring with body mass index and bone mineral density (GAPB) for improving predictions of mechanical complications after adult spinal deformity surgery. Spine J 2019;20:776-84.
  • 21. Yilgor C, Sogunmez N, Yavuz Y, et al. Global alignment and proportion (GAP) score: development and validation of a new method of analyzing spinopelvic alignment to predict mechanical complications after adult spinal deformity surgery. J Bone Joint Surg Am 2017;99:1661-72.
  • 22. Soroceanu A, Diebo BG, Burton D, et al. Radiographical and implant-related complications in adult spinal deformity surgery: incidence, patient risk factors, and impact on healthrelated quality of life. Spine (Phila Pa 1976) 2015;40:1414-21.
  • 23. Bianco K, Norton R, Schwab F, et al. Complications and intercenter variability of three-column osteotomies for spinal deformity surgery: a retrospective review of 423 patients. Neurosurg Focus 2014;36:E18.
  • 24. Pichelmann MA, Lenke LG, Bridwell KH, et al. Revision rates following primary adult spinal deformity surgery: six hundred forty-three consecutive patients followed-up to twenty-two years postoperative. Spine (Phila Pa 1976) 2010;35:219-26.
  • 25. Schwab FJ, Hawkinson N, Lafage V, et al. Risk factors for major peri-operative complications in adult spinal deformity surgery: a multi-center review of 953 consecutive patients. Eur Spine J 2012;21:2603-10.
  • 26. Denis F, Sun EC, Winter RB. Incidence and risk factors for proximal and distal junctional kyphosis following surgical treatment for Scheuermann kyphosis: minimum five-year follow-up. Spine (Phila Pa 1976) 2009;34:E729-34.
  • 27. Helgeson MD, Shah SA, Newton PO, et al. Evaluation of proximal junctional kyphosis in adolescent idiopathic scoliosis following pedicle screw, hook, or hybrid instrumentation. Spine (Phila Pa 1976) 2010;35:177-81.
  • 28. Hollenbeck SM, Glattes RC, Asher MA, et al. The prevalence of increased proximal junctional flexion following posterior instrumentation and arthrodesis for adolescent idiopathic scoliosis. Spine (Phila Pa 1976) 2008;33:1675-81.
  • 29. Kim YJ, Bridwell KH, Lenke LG, et al. Proximal junctional kyphosis in adolescent idiopathic scoliosis following segmental posterior spinal instrumentation and fusion: minimum 5-year follow-up. Spine (Phila Pa 1976) 2005;30:2045-50.
  • 30. Bridwell KH, Lenke LG, Cho SK, et al. Proximal junctional kyphosis in primary adult deformity surgery: evaluation of 20 degrees as a critical angle. Neurosurgery 2013;72:899-906.
  • 31. Kim HJ, Bridwell KH, Lenke LG, et al. Patients with proximal junctional kyphosis requiring revision surgery have higher postoperative lumbar lordosis and larger sagittal balance corrections. Spine (Phila Pa 1976) 2014;39:E576-80.
  • 32. Lau D, Clark AJ, Scheer JK, et al. Proximal junctional kyphosis and failure after spinal deformity surgery: a systematic review of the literature as a background to classification development. Spine (Phila Pa 1976) 2014;39:2093-102.
  • 33. O’Leary PT, Bridwell KH, Lenke LG, et al. Risk factors and outcomes for catastrophic failures at the top of long pedicle screw constructs: a matched cohort analysis performed at a single center. Spine (Phila Pa 1976) 2009;34:2134-9.
  • 34. Endo K, Suzuki H, Nishimura H, et al. Characteristics of sagittal spino-pelvic alignment in Japanese young adults. Asian Spine J 2014;8:599-604.
  • 35. Chaléat-Valayer E, Mac-Thiong JM, Paquet J, et al. Sagittal spino-pelvic alignment in chronic low back pain. Eur Spine J 2011;20 Suppl 5:634-40.
  • 36. Hasegawa K, Okamoto M, Hatsushikano S, et al. Normative values of spino-pelvic sagittal alignment, balance, age, and health-related quality of life in a cohort of healthy adult subjects. Eur Spine J 2016;25:3675-86.
  • 37. Nguyen JH, Buell TJ, Wang TR, et al. Low rates of complications after spinopelvic fixation with iliac screws in 260 adult patients with a minimum 2-year follow-up. J Neurosurg Spine 2019 Feb 1:1-9. https://doi.org/10.3171/2018.9.SPINE18239. [Epub].
  • 38. Unoki E, Miyakoshi N, Abe E, et al. Sacropelvic fixation with S2 alar iliac screws may prevent sacroiliac joint pain after multisegment spinal fusion. Spine (Phila Pa 1976) 2019;44:E1024-30.
  • 39. Charles YP, Ntilikina Y. Scoliosis surgery in adulthood: what challenges for what outcome? Ann Transl Med 2020;8:34.
  • 40. Kim YH, Ha KY, Chang DG, et al. Relationship between iliac screw loosening and proximal junctional kyphosis after long thoracolumbar instrumented fusion for adult spinal deformity. Eur Spine J 2020;29:1371-8.
  • 41. Horn SR, Segreto FA, Ramchandran S, et al. The influence of body mass index on achieving age-adjusted alignment goals in adult spinal deformity corrective surgery with full-body analysis at 1 year. World Neurosurg 2018;120:e533-45.

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Which Is More Predictive Value for Mechanical Complications: Fixed Thoracolumbar Alignment (T1 Pelvic Angle) Versus Dynamic Global Balance Parameter (Odontoid-Hip Axis Angle)
Neurospine. 2021;18(3):597-607.   Published online September 30, 2021
DOI: https://doi.org/10.14245/ns.2142452.226
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Which Is More Predictive Value for Mechanical Complications: Fixed Thoracolumbar Alignment (T1 Pelvic Angle) Versus Dynamic Global Balance Parameter (Odontoid-Hip Axis Angle)
Neurospine. 2021;18(3):597-607.   Published online September 30, 2021
DOI: https://doi.org/10.14245/ns.2142452.226
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Which Is More Predictive Value for Mechanical Complications: Fixed Thoracolumbar Alignment (T1 Pelvic Angle) Versus Dynamic Global Balance Parameter (Odontoid-Hip Axis Angle)
Image Image
Fig. 1. Measurement of global balance parameters. (A) Odontoid-hip axis (OD-HA) angle. OD-HA angle (white lines) is the angle between the vertical and the hightest point of the dens connecting the center of the femoral heads (black dotted line, center of the black circles). The OD-HA angle target value is +2° to -5°. (B) T1 pelvic angle (TPA). TPA (white dotted lines) corresponds to the angle between a line connecting the center of T1 to the center of the femoral heads (black dotted line, center of the black circles) and the line to the center of the S1 endplate (black line). The TPA target value is under 14°.
Fig. 2. Receiver operating characteristic (ROC) curve. Logistic regression (mechanical complication) in odontoid-hip axis angle. Odds ratio, 2.924; p=0.001; area under the curve=0.727

Fig. 1.

Fig. 2.

Which Is More Predictive Value for Mechanical Complications: Fixed Thoracolumbar Alignment (T1 Pelvic Angle) Versus Dynamic Global Balance Parameter (Odontoid-Hip Axis Angle)
Variable Total (n=199) OD-HA
 TPA
Normal (n=102) Abnormal (n=97) p-value Normal (n = 59) Abnormal (n=140) p-value
Demographics
 Age (yr) 67.36 ± 8.28 66.71 ± 8.23 68.052 ± 8.32 0.253 64.61 ± 8.97 68.52 ± 7.71 0.002*
 Sex 0.162 0.015†
  Male 26 (13.07) 10 (9.80) 16 (16.49) 13 (22.03) 13 (9.29)
  Female 173 (86.93) 92 (90.20) 81 (83.51) 46 (77.97) 127 (90.71)
 BMD -1.98 ± 1.05 -1.91 ± 1.03 -2.063 ± 1.07 0.299 -1.84 ± 0.85 -2.04 ± 1.12 0.170
 BMI (kg/m2) 23.98 ± 2.61 23.71 ± 2.37 24.261 ± 2.82 0.133 24.26 ± 2.85 23.86 ± 2.50 0.328
Postoperative parameters
 SVA 38.18 ± 39.98 34.73 ± 26.00 41.80 ± 50.60 0.221 26.98 ± 37.95 42.89 ± 40.01 0.010*
 PI–LL 15.81 ± 12.82 14.69 ± 11.88 16.98 ± 13.70 0.208 9.60 ± 10.44 18.43 ± 12.86 < 0.001*
 LL 35.03 ± 12.97 35.13 ± 13.43 34.92 ± 12.54 0.906 35.63 ± 11.67 34.78 ± 13.51 0.674
 PI 50.84 ± 11.91 49.82 ± 12.33 51.90 ± 11.42 0.220 45.22 ± 9.47 53.20 ± 12.07 < 0.001*
 PT 24.01 ± 9.77 23.22 ± 8.39 24.85 ± 11.02 0.243 18.19 ± 8.38 26.47 ± 9.29 < 0.001*
 SS 27.53 ± 10.39 27.65 ± 10.54 27.40 ± 10.29 0.862 27.90 ± 8.69 27.37 ± 11.06 0.718
Instrumentation
 Segments‡ 7.13 ± 2.41 6.95 ± 2.18 7.32 ± 2.62 0.282 7.12 ± 2.36 7.14 ± 2.44 0.964
 UIV§ 11.40 ± 2.54 11.69 ± 2.23 11.10 ± 2.81 0.101 11.39 ± 2.60 11.40 ± 2.52 0.980
 LIV§ 17.52 ± 1.18 17.62 ± 0.85 17.41 ± 1.44 0.225 17.51 ± 1.37 17.52 ± 1.09 0.949
 SPF 0.006† 0.529
  No 108 (54.27) 62 (60.78) 46 (47.42) 30 (50.85) 78 (55.71)
  Yes 91 (45.73) 40 (39.22) 52 (52.58) 29 (49.15) 62 (44.29)
Variable Total (n=199) OD-HA
 TPA
Normal (n=102) Abnormal (n=97) p-value Normal (n=59) Abnormal (n=140) p-value
Back VAS
 Preoperative 7.41 ± 1.98 7.43 ± 2.02 7.38 ± 1.94 0.860 7.53 ± 1.73 7.36 ± 2.08 0.585
 Postoperative 4.73 ± 2.47 4.51 ± 2.44 4.96 ± 2.48 0.200 4.12 ± 2.39 4.99 ± 2.46 0.023*
 Changes -2.68 ± 2.23 -2.92 ± 2.29 -2.42 ± 2.15 0.115 -3.41 ± 2.20 -2.37 ± 2.18 0.003*
Leg VAS
 Preoperative 6.76 ± 2.88 7.03 ± 2.82 6.49 ± 2.93 0.183 6.48 ± 3.00 6.89 ± 2.83 0.359
 Postoperative 4.44 ± 2.90 4.40 ± 2.79 4.47 ± 3.03 0.861 3.71 ± 2.59 4.74 ± 2.98 0.022*
 Changes -2.33 ± 2.89 -2.63 ± 2.95 -2.01 ± 2.82 0.133 -2.76 ± 3.20 -2.14 ± 2.75 0.168
ODI
 Preoperative 60.02 ± 17.04 59.91 ± 15.81 60.14 ± 18.32 0.923 60.57 ± 14.77 59.79 ± 17.96 0.770
 Postoperative 38.09 ± 19.85 35.19 ± 18.40 41.13 ± 20.93 0.034* 35.07 ± 17.03 39.36 ± 20.85 0.165
 Changes -21.94 ± 20.21 -24.72 ± 20.16 -19.01 ± 19.95 0.046* -25.50 ± 17.05 -20.44 ± 21.28 0.107
SRS-22
 Preoperative 2.38 ± 0.47 2.37 ± 0.49 2.39 ± 0.45 0.762 2.38 ± 0.47 2.38 ± 0.47 0.931
 Postoperative 3.16 ± 0.72 3.25 ± 0.72 3.07 ± 0.72 0.081 3.29 ± 0.71 3.11 ± 0.72 0.120
 Changes 0.78 ± 0.69 0.88 ± 0.73 0.68 ± 0.64 0.042* 0.91 ± 0.66 0.73 ± 0.70 0.092
SF-36 PCS
 Preoperative 27.18 ± 17.95 25.44 ± 17.19 29.01 ± 18.62 0.162 27.04 ± 17.75 27.24 ± 18.10 0.943
 Postoperative 43.38 ± 21.65 44.77 ± 20.90 41.91 ± 22.44 0.354 44.96 ± 20.50 42.71 ± 22.16 0.506
 Changes 16.20 ± 17.93 19.33 ± 18.55 12.90 ± 16.73 0.011* 17.92 ± 16.22 15.47 ± 18.61 0.381
SF-36 MCS
 Preoperative 35.85 ± 18.94 34.99 ± 18.35 36.76 ± 19.59 0.512 36.42 ± 20.74 35.61 ± 18.20 0.783
 Postoperative 53.44 ± 23.28 55.02 ± 23.74 51.77 ± 22.80 0.326 54.03 ± 23.55 53.19 ± 23.25 0.818
 Changes 17.59 ± 18.61 20.04 ± 20.01 15.02 ± 16.74 0.057 17.61 ± 19.25 17.58 ± 18.41 0.993
Variable Total (n=199) OD-HA
 TPA
Normal (n=102) Abnormal (n=97) p-value Normal (n = 59) Abnormal (n = 140) p-value
Mechanical complication < 0.001* 0.123
 Occurred 84 (42.2) 29 (28.4) 55 (56.7) 20 (33.9) 64 (450.7)
 Not occurred 115 (57.8) 73 (71.6) 42 (43.3) 39 (66.1) 76 (540.3)
PJK < 0.001* 0.135
 Occurred 80 (40.2) 28 (27.5) 52 (53.6) 19 (32.2) 61 (430.6)
 Not occurred 119 (59.8) 74 (72.5) 45 (46.4) 40 (67.8) 79 (560.4)
PJF 0.002* 0.925
 Occurred 43 (21.6) 13 (12.8) 30 (300.9) 13 (22.0) 30 (210.4)
 Not occurred 156 (78.4) 89 (87.3) 67 (690.1) 46 (78.0) 110 (780.6)
Implant related complication 0.008* 0.431
 Occurred 26 (13.1) 7 (6.9) 19 (190.6) 6 (10.2) 20 (14.3)
 Not occurred 173 (86.9) 95 (93.1) 78 (80.4) 53 (89.8) 120 (85.7)
Univariable (n = 199)
 Multivariable
OR (95% CI) p-value AUC OR (95% CI) p-value AUC
OD-HA 0.645 0.727
 Normal Reference Reference
 Abnormal 3.296 (1.830–5.938) < 0.001* 2.924 (1.567–5.455) 0.001*
TPA
 Normal Reference Reference
 Abnormal 1.642 (0.872–3.094) 0.125 1.370 (0.673–2.791) 0.386
Age 1.038 (1.000–1.077) 0.048* 1.018 (0.978–1.060) 0.390
Sex
 Female Reference
 Male 0.832 (0.363–1.904) 0.663
BMD 0.634 (0.473–0.850) 0.002* 0.739 (0.527–1.039) 0.082
BMI 1.199 (1.066–1.349) 0.003* 1.144 (1.008–1.299) 0.038*
SVA 1.009 (1.001–1.017) 0.020* 1.006 (0.997–1.014) 0.174
PI–LL 1.016 (0.994–1.039) 0.152
PI 1.005 (0.981–1.029) 0.690
LL 0.988 (0.967–1.010) 0.292
PT 1.013 (0.984–1.043) 0.381
SS 0.995 (0.968–1.022) 0.702
Fusion level segments 1.022 (0.909–1.148) 0.719
UIV 0.996 (0.891–1.113) 0.939
LIV 1.073 (0.836–1.377) 0.582
SPF
 None Reference Reference
 Done 1.731 (0.980–3.055) 0.059 1.324 (0.695–2.523) 0.393
Variable Total (n=199) Mechanical complication
 Proximal junctional kyphosis
 Proximal junctional failure
 Implant related complication
Normal (n=115) Occurred (n=84) p-value Normal (n=119) Occurred (n=80) p-value Normal (n=156) Occurred (n=43) p-value Normal (n = 173) Occurred (n = 26) p-value
Demographics
  Age 67.36 ± 8.28 66.36 ± 8.75 68.74 ± 7.42 0.045* 66.72 ± 8.45 68.31 ± 7.98 0.185 67.44 ± 8.17 67.07 ± 8.74 0.795 67.12 ± 8.18 69.00 ± 8.89 0.280
Sex 0.676 0.526 0.305 0.755
  Male 26 (13.07) 14 (12.17) 12 (14.29) 14 (11.76) 12 (15.00) 18 (11.54) 8 (18.60) 22 (12.72) 4 (15.38)
Female 173 (86.93) 101 (87.83) 72 (85.71) 105 (88.24) 68 (85.00) 138 (88.46) 35 (81.40) 151 (87.28) 22 (84.62)
BMD -1.98 ± 1.05 -1.78 ± 0.93 -2.26 ± 1.14 0.001* -1.81 ± 0.93 -2.24 ± 1.16 0.004* -1.87 ± 0.99 -2.40 ± 1.15 0.003* -1.86 ± 0.99 -2.78 ± 1.16 < 0.001*
BMI 23.98 ± 2.61 23.49 ± 2.46 24.64 ± 2.67 0.002* 23.59 ± 2.35 24.55 ± 2.87 0.011* 23.76 ± 2.35 24.75 ± 3.30 0.072 23.86 ± 2.40 24.76 ± 3.68 0.236
Postoperative parameters
SVA 38.18 ± 39.98 32.36 ± 30.77 46.14 ± 49.01 0.025* 31.44 ± 30.38 48.20 ± 49.57 0.008* 35.78 ± 34.76 46.86 ± 54.57 0.213 36.69 ± 37.36 48.07 ± 54.24 0.310
PI-LL 15.81 ± 12.82 14.69 ± 12.11 17.34 ± 13.66 0.151 15.16 ± 12.08 16.77 ± 13.87 0.386 16.17 ± 12.47 14.50 ± 14.08 0.450 15.66 ± 12.33 16.78 ± 15.97 0.734
LL 35.03 ± 12.97 35.86 ± 13.28 33.89 ± 12.52 0.293 35.81 ± 13.10 33.85 ± 12.76 0.295 34.74 ± 13.25 36.07 ± 12.01 0.554 34.43 ± 12.85 39.03 ± 13.29 0.091
PI 50.84 ± 11.91 50.55 ± 12.49 51.23 ± 11.14 0.691 50.98 ± 12.52 50.62 ± 11.01 0.836 50.91 ± 11.97 50.56 ± 11.84 0.866 50.09 ± 12.11 55.81 ± 9.24 0.022
PT 24.01 ± 9.77 23.50 ± 8.75 24.72 ± 11.03 0.382 23.97 ± 8.92 24.07 ± 10.98 0.945 24.35 ± 9.07 22.80 ± 12.01 0.358 23.78 ± 8.84 25.60 ± 14.66 0.542
SS 27.53 ± 10.39 27.77 ± 10.21 27.20 ± 10.69 0.704 27.67 ± 10.10 27.31 ± 10.87 0.809 27.28 ± 9.86 28.43 ± 12.23 0.519 27.14 ± 10.00 30.09 ± 12.64 0.178
Instrumentation
Segments† 7.13±2.41 7.08 ± 2.30 7.20 ± 2.56 0.721 7.01 ± 2.29 7.31 ± 2.58 0.384 7.03 ± 2.32 7.51 ± 2.69 0.242 7.02 ± 2.36 7.85 ± 2.63 0.104
UIV‡ 11.40 ± 2.54 11.41 ± 2.39 11.38 ± 2.75 0.940 11.51 ± 2.37 11.23 ± 2.77 0.435 11.51 ± 2.41 11.00 ± 2.94 0.248 11.53 ± 2.52 10.54 ± 2.52 0.064
LIV‡ 17.52 ± 1.18 17.48 ± 1.05 17.57 ± 1.34 0.582 17.51 ± 1.01 17.53 ± 1.40 0.942 17.53 ± 1.15 17.49 ± 1.28 0.855 17.54 ± 1.13 17.39 ± 1.44 0.538
SPF 0.063 0.081 0.084 0.210
  No 108 (54.27) 69 (60.00) 39 (46.43) 71 (59.66) 37 (46.25) 90 (57.69) 18 (41.86) 97 (56.07) 11 (42.31)
Yes 91 (45.73) 46 (40.00) 45 (53.57) 48 (40.34) 43 (53.75) 66 (42.31) 25 (58.14) 76 (43.93) 15 (57.69)
Table 1. Demographic variables and radiographic data between OD-HA and TPA

Values are presented as mean±standard deviation or number (%).

OD-HA, odontoind-hip axis angle; TPA, T1-pelvic angle; BMD, bone mineral density; BMI, body mass index; SVA, sagittal vertical axis; PI, pelvic incidence; LL, lumbar lordosis; PT, pelvic tilt; SS, sacral slope; UIV, upper most instrumented vertebra; LIV, lower most instrumented vertebra; SPF, spino-pelvic fixation.

p<0.05, statistically significantly differences in independent t-test.

p<0.05, statistically significantly differences in chi-square test (Fisher exact test).

The number of instrumented vertebral segments.

Numbering the spine. It starts with 1 for C1 and ends with 18 for S1. Number 11 stands for T11, and number 17 for L5.

Table 2. Clinical data between OD-HA versus TPA

Values are presented as mean±standard deviation.

OD-HA, odontoid-hip axis; TPA, T1-pelvic angle; VAS, visual analogue scale; ODI, Oswestry Disability Index; SRS, scoliosis research society; SF-36, 36-item Short Form Health Survey; PCS, physical component summary; MCS, mental component summary.

p<0.05, statistically significantly differences in independent t-test.

Table 3. Occurrence of complications between OD-HA versus TPA

Values are presented as number (%).

OD-HA, odontoid-hip axis; TPA, T1-pelvic angle; PJK, proximal junctional kyphosis; PJF, proximal junctional failure.

p<0.05, statistically significantly differences in chi-square test.

Table 4. Logistic regression (mechanical complication) in OD-HA angle

OD-HA, odontoid-hip axis; OR, odds ratio; CI, confidence interval; AUC, area under the curve; TPA, T1 pelvic angle; BMD, bone mineral density; BMI, body mass index; PI, pelvic index; LL, lumbar lordosis; PT, pelvic tilt; SS, sacral slope; SVA, sagittal vertical axis; UIV, uppermost instrumented vertebra; LIV, lowest instrumented vertebra; SPF, spino-pelvic fixation.

p<0.05, statistically significantly differences in logistic regression.

Table 5. Risk factors according to occurrence of complications

Values are presented as mean±standard deviation or number (%).

BMD, bone mineral density; BMI, body mass index; SVA, sagittal vertical axis; PI, pelvic incidence; LL, lumbar lordosis; PT, pelvic tilt; SS, sacral slope; UIV, upper most instrumented vertebra; LIV, lower most instrumented vertebra; SPF, spino-pelvic fixation.

p<0.05, statistically significantly differences in independent t-test.

The number of instrumented vertebral segments.

Numbering the spine. It starts with 1 for C1 and ends with 18 for S1. Number 11 stands for T11, and number 17 for L5.

Table 1.

Table 2.

Table 3.

Table 4.

Table 5.

NS : Neurospine
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