Supra-acetabular line is better than supra-iliac line for coronal balance referencing-a study of perioperative whole spine X-rays in degenerative lumbar scoliosis and ankylosing spondylitis patients

The radiographic assessments of spino-pelvic compensation using IoT-based real-time ischial pressure adjustment

In malalignment syndrome, the spino-pelvic alignment correction with foot orthotics can be applied only to a standing position in the coronal plane. Considering the fact that the average time Koreans spend sitting in a chair is 7.5 hours per day, studies on spino-pelvic correction in sitting position is needed. The purpose of this study is to investigate the pressure changes and radiographic assessment of spino-pelvic alignment using a chair equipped with a height-adjustable seat-plate. This study was conducted on 30 participants with spinopelvic malalignment. All participants were subjected to measure buttocks interface pressure while seated using a smart chair in three consecutive steps: 1. on initial seated, 2. on balancing seated, and then. 3. on 1 hour balancing seated. Radiographically, the five spino-pelvic parameters such as shoulder height differences (SHD), iliac crest height differences (ICHD), leg length discrepancy (LLD), pelvic oblique angle (POA), and coronal imbalance were analyzed to investigate the effect of pelvic imbalance compensation on spino-pelvic alignment. Statistical analysis was performed using ANOVA and paired t test. The pressure discrepancy improvement between buttocks from 36.4 ± 32.3 mm on initial seated to 15.7 ± 20.3 mm on balancing, 12.7 ± 10.9 mm on 1hr balancing seated (Ω, P = .008). The radiographic results of pelvic imbalance compensation during seated show a statistical improvement of average SHD (from −0.9 to −0.8 mm, P = .005) and average ICHD (from 9.5 to 2.5 mm, P = .037). For a standing posture after use of smart chair, average SHD value (−3.0 to −1.0 mm, P = .005), ICHD (from 1.8 to 0.8 mm, P = .016), and average LLD value (0.8–0.1 mm, P = .033) were statistically significant improved. Spine-pelvic malalignment can be improved by individually customized pelvic compensation using balanced seat plate height adjustments under the real-time pressure sensing and monitoring on the buttocks while seated.

A novel integrated global coronal aligner helps prevent post-operative standing coronal imbalance in adult spinal deformity patients fused to pelvis: technical notes and preliminary results

Background

Chieving postoperative coronal balance in adult spinal deformity correction surgeries can be challenging. Even with T square rod technique, there were still some cases with good intraoperative coronal alignment but unsatisfactory post-operative standing coronal imbalance. Thus, the novel techniques to obtain global coronal balance are still in great needs. The purpose of this study was to describe a novel integrated global coronal aligner (IGCA) and evaluate its efficacy on avoidance of post-operative coronal imbalance in adult spinal deformity patients fused to pelvis.

Methods

A detailed description of IGCA technique was presented. 52 ASD patients fused to pelvis were divided into two groups (IGCA group, n = 27; and non-IGCA group, n = 25) according to whether intraoperative IGCA was used or not. Preoperative demographics and postoperative outcomes were compared.

Results

There were no significant differences regarding coronal balance difference (CBD) and imbalance/balance ratio between IGCA and non-IGCA groups preoperatively. After surgery, CBD in IGCA group was significantly improved from 24.7 ± 20.3 mm preoperatively to 12.6 ± 6.4 mm postoperatively (t = 3.185 p = 0.004), and imbalance/balance ratio decreased significantly from 55.6% (15/27) preoperatively to 11.1% (3/27) postoperatively (χ2 = 12.000, p = 0.001), while CBD and imbalance/balance ratio in non-IGCA group were not significantly improved. Compared to non-IGCA group, the amount of correction in CBD was significantly larger in IGCA group (t = 3.274, P = 0.002), and imbalance/balance ratio in IGCA group was significantly lowered (χ2 = 8.606 p = 0.003). Further logistic regression analysis revealed IGCA technique was associated with increased odds ratio for postoperative coronal balance (odds ratio: 7.385; 95% confidence interval 1.760–30.980; P = 0.006).

Conclusions

The novel intraoperative IGCA technique could help improve CBD and reduce imbalance/balance ratio. It could help prevent post-operative coronal imbalance in adult spinal deformity patients fused to pelvis.

Level of evidence

3

2-Dimensional Long Film O-Arm Imaging, an Alternative When Intraoperative Fluoroscopy Is Inadequate

Obtaining intraoperative images of the spine in the obese patient and at the cervicothoracic junction have historically been technically difficult due to variable penetration and x-ray scatter. This is particularly true for spinal deformity cases, where clear visualization of the end plates is needed to determine if functional alignment has been restored to the spine. The novel "2D long film" functionality for the Medtronic O-arm is capable of capturing the x-ray backscatter, producing enhanced intraoperative images. Furthermore, images can be obtained along the gantry translation of the O-arm and combined into a single long image, optimizing the workflow of surgeons who use the O-arm for intraoperative navigation. The purpose of this report is to highlight 2 example spinal deformity cases that underscore the utility of this imaging technology. In both cases, standard intraoperative fluoroscopy visualization was unacceptable, so 2D long film images were obtained to assess postcorrection spinal alignment.

[Surgical challenges with spinal balance in adult spinal deformities-the forgotten coronal plane]

This article gives a brief overview of the importance, planning and correction of coronal spinal imbalance in patients with adult and pediatric spinal deformity.

[Risk factors analysis of coronal imbalance after posterior long-level fixation and transforaminal lumbar interbody fusion for degenerative lumbar scoliosis]

OBJECTIVE

To explore the risk factors of coronal imbalance after posterior long-level fixation and fusion for degenerative lumbar scoliosis.

METHODS

Retrospectivly analyzed the clinical records of 41 patients with degenerative lumbar scoliosis who had received posterior long-level fixation and fusion with selective transforaminal lumbar interbody fusion (TLIF) accompanied by Ponte osteotomy between August 2011 and July 2016. Patients were divided into imbalance group (group A, 11 cases) and balance group (group B, 30 cases) according to state of coronal imbalance measured at last follow-up. The radiographic parameters at preoperation and last follow-up were measured, and the variance of preoperative and last follow-up parameters were calculated. The radiographic parameters included coronal Cobb angle, coronal balance distance (CBD), apical vertebral translation (AVT), apical vertebral rotation (AVR), Cobb angle of lumbar sacral curve (LSC), and L 5 tilt angle (L 5TA). Univariate analysis was performed for the factors including gender, age, preoperative T value of bone mineral density, number of instrumented vertebra, upper and lower instrumented vertebra, segments of TLIF, decompression, and Ponte osteotomy, as well as the continuous variables of preoperative imaging parameters with significant difference were converted into two-category variables, obtained the influence factors of postoperative coronal imbalance. Multivariate logistic regression analysis was performed to verify the risk factors from the preliminary screened influence factors and the variance of imaging parameters with significant difference between the two groups.

RESULTS

The follow-up time of groups A and B was (3.76±1.02) years and (3.56±1.03) years respectively, there was no significant difference between the two groups ( t=0.547, P=0.587). The coronal Cobb angle, AVT, LSC Cobb angle, and L 5TA in group A were significantly higher than those in group B before operation ( P<0.05), and all the imaging parameters in group A were significantly higher than those in group B at last follow-up ( P<0.05). There was no significant difference between the two groups in parameters including the variance of coronal Cobb angle, AVT, and LSC Cobb angle before and after operation ( P>0.05), and there were significant differences between the two groups in parameters including the variance of CBD, L 5TA, and AVR ( P<0.05). Univariate analysis showed that preoperative L 5TA was the influencing factor of postoperative coronal imbalance ( P<0.05). Multivariate logistic regression analysis showed that preoperative L 5TA≥15° was an independent risk factor of postoperative coronal imbalance, and variance of pre- and post-operative AVR was a protective factor.

CONCLUSION

Preoperative L 5TA≥15° is an independent risk factor for coronal imbalance in patients with degenerative lumbar scoliosis after posterior long-level fixation and fusion.