Factors related to postoperative coronal imbalance in adult lumbar scoliosis

Poorer clinical outcomes after THA in patients with a spinal scoliotic deformity: a case-control study of 268 patients assessed with PROMS

INTRODUCTION

Spinal deformities can lead to specific complications after total hip arthroplasty (THA), such as functional leg length discrepancy due to a fixed pelvic obliquity, as well as an increased risk of prosthetic instability due to a lack of adaptive pelvic mobility, but these issues were not investigated in large comparative series. Therefore a retrospective case-control study was done aiming: 1) to analyze the impact of a preoperative scoliotic deformity on the functional outcomes of patients who underwent THA with a minimum 1-year follow-up, 2) to measure the prevalence of scoliosis in both the case and control groups 3) to screen other factors that may be correlated with poorer clinical outcomes in patients who underwent THA, including age, gender, Body Mass index (BMI), American Society of Anesthesiologists (ASA) score, primary THA etiology and postoperative complication occurrence.

HYPOTHESIS

The presence of scoliosis would have a negative impact on THA outcomes as assessed by PROMs.

MATERIALS AND METHODS

A case-control study was conducted using prospectively collected data including 268 patients who underwent THA between January 2009 and December 2021 through a direct anterior approach by the same senior surgeon. Cases were identified based on a 1-year follow-up modified Harris Hip score (mHHS) lower than 81 while controls were defined as patients with an excellent 1-year follow-up mHHS score (equal to or higher than 81). Three controls were randomly matched with each case based on the surgery period. To assess the impact of a concurrent scoliosis on clinical outcomes, a mathematical univariate and multivariate logistic model was used, including other confounding factors (age, gender, ASA score, BMI, Complication occurrence, etiology), to calculate the adjusted odds-ratio.

RESULTS

In the multivariate analysis, scoliosis was found to be a significant risk factor, with a three-fold higher adjusted odds-ratio of lower mHHS score (adjOR = 3.1; 95 CI:1.4-7, (p < 0.01)). The mean mHHS score was significantly lower in the scoliosis group compared to the non-scoliosis group (77 vs 84 (p = 0.01)) as well as the mean Oxford Hip Score (36 vs 43 (p < 0.001)). Among the other assessed risk factors, only the occurence of a postoperative complication was associated with an increased odds ratio of poorer mHHS scores (adjOR = 7.1; 95 CI: 2.78 - 18.24, (p < 0.001). The prevalence of scoliosis in our practice was 19%.

DISCUSSION

Given the prevalence of 19% found in our study, we recommend screening for scoliosis in all patients scheduled for THA. Our results indicate that patients who had scoliosis experienced lower PROMs scores compared to those who had not. Surgeons should consider delivering this information to patients who have scoliosis undergoing THA to mitigate patient dissatisfaction.

LEVEL OF EVIDENCE

III; retrospective case-control study.

Do different pathologies of adult spinal deformity (idiopathic lumbar scoliosis against de novo lumbar scoliosis) affect preoperative and postoperative selfimage?

STUDY DESIGN

Retrospective single-center study.

PURPOSE

This study aimed to examine the factors associated with the self-image domain of the Scoliosis Research Society-22 revised (SRS-22r) in patients who underwent corrective surgery for adult idiopathic scoliosis (AdIS).

OVERVIEW OF LITERATURE

Adult spinal deformity (ASD) can be classified into AdIS and de novo scoliosis. However, no studies have investigated the effect of different ASD pathologies on self-image.

METHODS

This study enrolled 60 patients who underwent corrective surgery and were followed up for >2 years postoperatively. AdIS was defined as adolescent idiopathic scoliosis in patients who had no history of corrective surgery, had a primary thoracolumbar/lumbar (TL/L) curve, and were ≥30 years old at the time of surgery.

RESULTS

The AdIS (n=23; mean age, 53.1 years) and de novo (n=37; mean age, 70.0 years) groups were significantly different in terms of the main thoracic and TL/L curves, sagittal vertical axis, thoracic kyphosis, and thoracolumbar kyphosis preoperatively. The scores in the self-image domain of the SRS-22r (before surgery/2 years after surgery [PO2Y]) were 2.2/4.4 and 2.3/3.7 in the AdIS and de novo groups, respectively, and PO2Y was significantly different between the two groups (p<0.001). Multivariate regression analysis revealed that AdIS was an independent factor associated with self-image at PO2Y (p=0.039).

CONCLUSIONS

AdIS, a spinal deformity pathology, was identified as a significant factor associated with the self-image domain of SRS-22r in patients who underwent corrective surgery. AdIS is not solely classified based on pathology but also differs in terms of the clinical aspect of self-image improvement following corrective surgery.

Risk Factors of Postoperative Coronal Balance Transition in Degenerative Lumbar Scoliosis

STUDY DESIGN

Retrospective radiographic study.

OBJECTIVE

To determine the potential risk factors influencing the transition of postoperative coronal balance in degenerative lumbar scoliosis (DLS) patients.

SUMMARY OF BACKGROUND DATA

As time passes after surgery, the spinal sequence of DLS patients may dynamically shift from coronal balance to imbalance, causing clinical symptoms. However, the transition of postoperative coronal balance and its risk factors have not been effectively investigated.

MATERIALS AND METHODS

We included 156 DLS patients. The cohort was divided into immediate postoperative coronal balance with follow-up balance (N=73) and follow-up imbalance (N=21), immediate postoperative coronal imbalance (CIB) with follow-up balance (N=23), and follow-up imbalance (N=39). Parameters included age, sex, classification of coronal balance, coronal balance distance, fusion of L5 or S1, location of apical vertebra, apical vertebral translation (AVT), Cobb angle of the main curve and lumbar-sacral curve, tilt and direction of L4/5, tilt and direction of upper instrumented vertebra (UIV), and Cobb angle of T1-UIV. Statistical testing was performed using chi-square/Fisher exact test, t tests or nonparametric tests, correlation testing, and stepwise logistic regression.

RESULTS

We identified a significant difference in preoperative AVT, preoperative Cobb angle, and immediate postoperative UIV tilt between patients with and without follow-up balance. Logistic regression analysis demonstrated factors associated with follow-up CIB included preoperative AVT ( P =0.015), preoperative Cobb angle ( P =0.002), and tilt of immediate postoperative UIV ( P =0.018). Factors associated with immediate postoperative CIB in patients with follow-up coronal balance were sex, correction ratio of the main curve, and direction of L4. Logistic regression analysis further identified a correction ratio of main curve ≤0.7 ( P =0.009) as an important predictive factor.

CONCLUSION

Patients with immediate postoperative coronal balance and higher preoperative AVT, preoperative Cobb angle, and tilt of immediate postoperative UIV were more likely to experience follow-up CIB. A correction ratio of the main curve ≤0.7 was an independent predictor of follow-up CIB.

LEVEL OF EVIDENCE

3.

Adherence to the Obeid coronal malalignment classification and a residual malalignment below 20 mm can improve surgical outcomes in adult spine deformity surgery

PURPOSE

Coronal balance is a major factor impacting the surgical outcomes in adult spinal deformity (ASD). The Obeid coronal malalignment (O-CM) classification has been proposed to improve the coronal alignment in ASD surgery. Aim of this study was to investigate whether a postoperative CM < 20 mm and adherence to the O-CM classification could improve surgical outcomes and decrease the rate of mechanical failure in a cohort of ASD patients.

METHODS

Multicenter retrospective analysis of prospectively collected data on all ASD patients who underwent surgical management and had a preoperative CM > 20 mm and a 2-year follow-up. Patients were divided in two groups according to whether or not surgery had been performed in adherence to the guidelines of the O-CM classification and according to whether or not the residual CM was < 20 mm. The outcomes of interest were radiographic data, rate of mechanical complications and Patient-Reported Outcome Measures.

RESULTS

At 2 years, adherence to the O-CM classification led to a lower rate of mechanical complications (40 vs. 60%). A coronal correction of the CM < 20 mm allowed for a significant improvement in SRS-22 and SF-36 scores and was associated with a 3.5 times greater odd of achieving the minimal clinical important difference for the SRS-22.

CONCLUSION

Adherence to the O-CM classification could reduce the risk of mechanic complications 2 years after ASD surgery. Patients with a residual CM < 20 mm showed better functional outcomes and a 3.5 times greater odd of achieving the MCID for the SRS-22 score.

New Effective Intraoperative Techniques for the Prevention of Coronal Imbalance after Circumferential Minimally Invasive Correction Surgery for Adult Spinal Deformity

This study aimed to devise measures and investigate their effect on coronal imbalance (CI) after circumferential minimally invasive correction surgery (CMIS) with lateral lumbar interbody fusion and percutaneous pedicle screw for adult spinal deformity (ASD). A total of 115 patients with ASD who underwent CMIS from the lower thoracic spine to the ilium were included. Patients were stratified based on the distance between the spinous process of the upper instrumented vertebra and central sacrum vertical line (UIV-CSVL) after the first intraoperative rod application into groups P (UIV-CSVL > 10 mm, n = 50) and G (UIV-CSVL < 10 mm, n = 65). Measures to correct postoperative CI introduced during surgery, preoperative and postoperative UIV-CSVL, and changes in UIV-CSVL after various measures (ΔUIV-CSVL) were investigated in group P. Rod rotation (RR), S2 alar-iliac screw distraction (SD), and kickstand-rod (KR) technique were performed in group P. Group P was further divided into group RR (n = 38), group SD (RR and SD) (n = 7), and group KR (RR and KR) (n = 5); the ΔUIV-CSVLs were 13.9 mm, 20.1 mm, and 24.4 mm in these three groups, respectively. Postoperative C7-CSVL < 10 mm was achieved in all three correction groups. In conclusion, our measures enabled sufficient correction of the UIV-CSVL and are useful for preventing CI after CMIS for ASD.

Global Coronal Malalignment in Degenerative Lumbar Scoliosis and Priority-Matching Correction Technique to Prevent Postoperative Coronal Decompensation

STUDY DESIGN

A prospective case-control study.

OBJECTIVE

To analyze global coronal malalignment (GCM) in degenerative lumbar scoliosis (DLS) and to prospectively investigate the performance of priority-matching correction technique on preventing postoperative coronal imbalance.

METHODS

A total of 444 DLS inpatients and outpatients were recruited. GCMs were classified into 2 types: Type 1, GCM with thoracolumbar (TL/L) curve as the main contribution on coronal imbalance; Type 2, GCM with lumbosacral (LS) curve as the main contribution on coronal imbalance. Patients receiving priority-matching correction were assigned to Group P-M and receiving traditional correction were assigned to Group T form August 2020. The fundamental principle of priority-matching technique was to first correct the key curve contributing to coronal imbalance rather than the curve with greater magnitude.

RESULTS

Type 1 GCM accounted for 45% and Type 2 GCM accounted for 55% of patients. Type 2 GCM was detected to have greater LS Cobb angle and L4 tilt. At 1-year follow-up, 29.8% of patients with Type 2 GCM, whereas 11.7% of patients with Type 1 GCM were observed to have postoperative coronal decompensation. Patients with postoperative imbalance were revealed to have greater preoperative LS Cobb angle and L4 tilt and smaller correction extent of LS curve and L4 tilt. 6.25% of patients developed postoperative coronal imbalance in Group P-M, whereas 40.5% developed in Group T.

CONCLUSION

Highlighting priority and aggressive correction of the key curve to coronal imbalance, priority-matching technique was proved to be able to limit the development of postoperative coronal decompensation.

Independent Risk Factors of Postoperative Coronal Imbalance after Adult Spinal Deformity Surgery

The aim of the present study is to elucidate preoperative risk factors for inadequate correction of coronal imbalance and/or creation of new postoperative coronal imbalance (iatrogenic CIB) in patients who undergo surgery for Adult Spinal Deformity (ASD). A retrospective review of adults who underwent posterior spinal fusion (>5 levels) for ASD was performed. Patients were divided into groups according to the Nanjing classification: type A (CSVL < 3 cm), type B (CSVL > 3 cm and C7 plumb line shifted to major curve concavity), and type C (CSVL > 3 cm and C7 plumb line shifted to major curve convexity). They were also divided according to postoperative coronal balance in balanced (CB) vs. imbalanced (CIB) and according to iatrogenic coronal imbalance (iCIB). Preoperative, postoperative, and last follow-up radiographical parameters and intraoperative data were recorded. A multivariate analysis was performed to identify independent risk factors for CIB. A total of 127 patients were included (85 type A, 30 type B, 12 type C). They all underwent long (average levels fused 13.3 ± 2.7) all-posterior fusion. Type C patients were more at risk of developing postoperative CIB (p = 0.04). Multivariate regression analysis indicated L5 tilt angle as a preoperative risk factor for CIB (p = 0.007) and indicated L5 tilt angle and age as a preoperative independent risk factors for iatrogenic CIB (p = 0.01 and p = 0.008). Patients with a preoperative trunk shift towards the convexity of the main curve (type C) are more prone to postoperative CIB and leveling the L4 and L5 vertebrae is the key to achieve coronal alignment preventing the "takeoff phenomenon".

The top 100 most-cited articles on adult spinal deformity: The most popular topics are still sagittal plane parameters and complications

Purpose

This study aimed to summarize the characteristics of the 100 most-cited articles on adult spinal deformity (ASD) and to analyze past and current research hotspots and trends.

Methods

Literature searches (from inception to 28 April 2022) using Web of Science databases were conducted to identify ASD-related articles. The top 100 most-cited articles were collected for further analysis. Meanwhile, author keywords from articles published in the last 5 years were selected for further analysis.

Results

The top 100 most-cited articles on ASD were selected from 3,354 papers. The publication year ranged from 1979 to 2017, and all papers were written in English. The citation count among them ranged from 100 to 1,145, and the mean citation number was 215.2. The foremost productive first author was Schwab F. University of Washington had the largest number of publications. The United States of America had the largest number of published articles (n = 84) in this field. Spine was the most popular journal. Complications were the most studied themes. The visualization analysis of author keywords from the literature in the recent 5 years showed that complications, sagittal plane parameters, and surgical techniques are still the research hotspots, and minimally invasive surgery will continue to develop rapidly.

Conclusion

Based on a comparative analysis of the results of bibliometric and visualization, complications and sagittal plane parameters are still the major topics of research at present and even later, and minimally invasive surgery has a growth trend in this field of ASD.

Risk factors for coronal oblique take-off following adult spinal deformity surgery using lateral lumbar interbody fusion and open posterior corrective fusion

PURPOSE

To evaluate risk factors associated with oblique take-off (OT) following lateral lumbar interbody fusion (LLIF) for adult spinal deformity.

METHODS

Thirty-nine consecutive patients (mean age 67.9 years) with scoliosis of the lumbar curve (> 30°) were evaluated. Multilevel LLIF, followed by open thoraco-pelvic posterior corrective fusion after 1 week, was performed. We defined OT as a distance of > 25 mm between the C7 plumb line and the central sacral vertical line and examined risk factors by dividing the patients into the OT and non-OT groups.

RESULTS

OT occurred in 11 patients (28%), all showing a tilt to the convex side. The correction rate of the lumbar curve was approximately 70% range for both groups, which indicated good correction. Preoperative radiographs showed a high L1-central sacral vertical line in the standing position; high L5 tilt in the supine position; high L3, L4, and L5 tilts to the convex side in the supine-bending position; and a high L4 vertebral wedge on the convex side in OT cases. Multiple logistic regression analysis showed that an L4 tilt to the concave side in the bending position was the most effective predictor of OT (odds ratio = 1.104, P = 0.047). For a cutoff value of 16°, the sensitivity and specificity were 73% and 61%, respectively, according to the receiver operating characteristic curve analysis (area under the curve = 0.73).

CONCLUSION

OT occurred in 28% of adult scoliosis patients following LLIF. An L4 tilt > 16° to the concave side in the bending position was the most valuable risk factor.

LEVEL OF EVIDENCE

IV.

Kickstand rods and correction of coronal malalignment in patients with adult spinal deformity

PURPOSE

Coronal malalignment (CM) is a challenging spinal deformity to treat. The kickstand rod (KR) technique is powerful for correcting truncal shift. This study tested the hypothesis that the KR technique provides superior coronal alignment correction in adult deformity compared with traditional rod techniques.

METHODS

A retrospective evaluation of a prospectively collected multicenter database was performed. A 2:1 matched cohort of non-KR accessory rod and KR patients was planned based on preoperative coronal balance distance (CBD) and a vector of global shift. Patients were subgrouped according to CM classification with a 30-mm CBD threshold defining CM, and comparisons of surgical and clinical outcomes among groups was performed.

RESULTS

Twenty-one patients with preoperative CM treated with a KR were matched to 36 controls. KR-treated patients had improved CBD compared with controls (18 vs. 35 mm, P < 0.01). The postoperative CBD did not result in clinical differences between groups in patient-reported outcomes (P ≥ 0.09). Eight (38%) of 21 KR patients and 12 (33%) of 36 control patients with preoperative CM had persistent postoperative CM (P = 0.72). CM class did not significantly affect the likelihood of treatment failure (postoperative CBD > 30 mm) in the KR cohort (P = 0.70), the control cohort (P = 0.35), or the overall population (P = 0.31).

CONCLUSIONS

Application of the KR technique to coronal spinal deformity in adults allows for successful treatment of CM. Compared to traditional rod techniques, the use of KRs did not improve clinical outcome measures 1 year after spinal deformity surgery but was associated with better postoperative coronal alignment.