Retrospective review of prospectively-collected, multicenter adult spinal deformity (ASD) databases.
To apply artificial intelligence (AI)-based hierarchical clustering as a step toward a ...classification scheme that optimizes overall quality, value, and safety for ASD surgery.
Prior ASD classifications have focused on radiographic parameters associated with patient reported outcomes. Recent work suggests there are many other impactful preoperative data points. However, the ability to segregate patient patterns manually based on hundreds of data points is beyond practical application for surgeons. Unsupervised machine-based clustering of patient types alongside surgical options may simplify analysis of ASD patient types, procedures, and outcomes.
Two prospective cohorts were queried for surgical ASD patients with baseline, 1-year, and 2-year SRS-22/Oswestry Disability Index/SF-36v2 data. Two dendrograms were fitted, one with surgical features and one with patient characteristics. Both were built with Ward distances and optimized with the gap method. For each possible n patient cluster by m surgery, normalized 2-year improvement and major complication rates were computed.
Five hundred-seventy patients were included. Three optimal patient types were identified: young with coronal plane deformity (YC, n = 195), older with prior spine surgeries (ORev, n = 157), and older without prior spine surgeries (OPrim, n = 218). Osteotomy type, instrumentation and interbody fusion were combined to define four surgical clusters. The intersection of patient-based and surgery-based clusters yielded 12 subgroups, with major complication rates ranging from 0% to 51.8% and 2-year normalized improvement ranging from -0.1% for SF36v2 MCS in cluster 1,3 to 100.2% for SRS self-image score in cluster 2,1.
Unsupervised hierarchical clustering can identify data patterns that may augment preoperative decision-making through construction of a 2-year risk-benefit grid. In addition to creating a novel AI-based ASD classification, pattern identification may facilitate treatment optimization by educating surgeons on which treatment patterns yield optimal improvement with lowest risk.
4.
Revision surgery represents a major event for patients undergoing adult spinal deformity (ASD) surgery. Previous reports suggest that ASD surgery has minimal or no impact on health-related-quality of ...life (HRQOL) outcomes.
The present study aims to investigate the impact of early reoperations within the first year on HRQOL and on the likelihood of reaching the minimally clinically important difference (MCID) after ASD surgery.
This is a retrospective analysis of prospectively collected data from consecutive surgically treated adult deformity surgery patients included in a multicenter, international database.
The present study included 280 patients from a multicenter international prospective database.
Oswestry Disability Index (ODI), Short Form-36 (SF-36), Scoliosis Research Society-22 (SRS-22), MCID were evaluated in this work.
Consecutive surgical patients with ASD recruited prospectively in six different centers from four countries with a minimum 2-year follow-up were stratified into two groups: R (revision surgery within the first year) and NR (no revision). Health-related-quality of life (ODI, SF-36, SRS-22) was assessed and compared at 6-month, 1-year, and 2-year follow-up stages. Statistical analysis included chi-square tests, Student t tests, and linear mixed models.
Forty-three patients (R Group) received 46 revision surgeries. Nineteen patients (41.3%) had implant-related complications, 9 patients (19.6%) had deep surgical site infections, 9 patients (19.6%) had proximal junctional kyphosis, 3 patients (6.5%) had hematoma, and 6 patients (13%) had other complications. Baseline characteristics differed between groups.
At 6 months, all HRQOL scores improved in both groups, except in the SF-36 Mental Component Summary and SRS-22 mental health domain in the R Group. At 1 year, ODI and SRS-22 improvement was significantly greater in the NR Group, exceeding the reported MCID. At the 2-year follow-up, ODI, SRS-22, SF-36 MCS, and SF-36 PCS improvement was similar in both groups. However, postoperative change was only above the MCID for SF-36 PCS, ODI, and SRS-22 in the NR Group.
Early unanticipated revision surgery has a negative impact on mental health at 6 months and reduces the chances of reaching an MCID improvement in SRS-22, SF-36 PCS, and ODI at the 2-year follow-up.
A retrospective analysis of data collected prospectively in an adult spine deformity multicenter database.
The aim of this study was to determine the impact of adult scoliosis (AS) on the type of ...Roussouly sagittal shape in terms of classification applicability, scoliosis modification of a patient theoretical sagittal shape, and coronal-sagittal deformity associations.
Roussouly described a four-type sagittal shape classification in healthy individuals, which has been also applied to patients with degenerative spinal disease. However, it remains uncertain if its principles can be applied to AS patients.
AS patients recorded in a prospective multicenter database of adult spinal deformity were included. Preoperative sagittal radiographs were analyzed using the KEOPS software to measure pelvic parameters, global sagittal alignment, and the various criteria used for the Roussouly classification. The different sagittal shape types were compared using the Chi-square and McNemars tests, and analysis of variance with Bonferroni correction.
The classification was applicable to all of the 190 analyzed AS patients. In addition to Roussouly criteria, two parameters helped differentiate the different shapes: T10-L2 angle (24° ± 19 type-1; 14° ± 15 type-2; 3° ± 15 type-3; 0.4° ± 14 type-4; P < 0.001), and lordosis distribution index (90% ± 17 type-1; 83% ± 16 type-2; 73% ± 21 type-3; 63% ± 16 type-4; P < 0.001). AS changed the theoretical shape in 34% of the patients (P < 0.001). Curve etiology and curve pattern were not associated with any particular type of sagittal shape (P > 0.05). Type-1 was associated with older patients (P = 0.02), degenerative curves (P = 0.02), and greater PI-LL mismatch (P = 0.012). Types 3 to 4 were associated with younger age and idiopathic etiology (P < 0.001).
Roussouly four-type sagittal shape classification could be applied to AS patients. AS modified the theoretical type in one of every three patients. No particular association was found between the sagittal types and specific coronal deformities. Sagittal shape recognition in patients with AS will help restore the appropriate theoretical shape through surgery, which can eventually lead to better surgical outcomesLevel of Evidence: 2.
The minimum clinically important difference (MCID), an important concept to evaluate the effectiveness of treatments, might not be a single “magical” constant for any given health-related quality of ...life (HRQoL) scale. Thus, we analyzed the effects of various factors on MCIDs for several HRQoL measures in an adult spinal deformity population.
Surgical and nonsurgical patients from a multicenter adult spinal deformity database who had completed pretreatment and 1-year follow-up questionnaires (Core Outcome Measures Index COMI, Oswestry Disability Index ODI, Medical Outcomes Study 36-item short-form questionnaire, 22-item Scoliosis Research Society Outcomes questionnaire, and an anchor question of “back health”–related change during the previous year) were evaluated. The MCIDs for each HRQoL measure were calculated using an anchor-based method and latent class analysis for the overall population and subpopulations stratified by age, gender, and baseline scores (ODI and COMI) separately for patients with positive versus negative perceptions of change.
Patients with a baseline ODI score of <20, 20–40, and >40 had an MCID of 2.24, 11.35, and 26.57, respectively. Similarly, patients with a baseline COMI score of <2.75, 2.8–5.4, and >5.4 had an MCID of 0.59, 1.38, and 3.67 respectively. The overall MCID thresholds for deterioration and improvement were 0.27 and 2.62 for COMI, 2.23 and 14.31 for ODI, and 0.01 and 0.71 for 22-item Scoliosis Research Society Outcomes questionnaire, respectively.
The results from the present study have demonstrated that MCIDs change in accordance with the baseline scores and direction of change but not by age or gender. The MCID, in its current state, should be considered a concept rather than a constant.
Retrospective review of prospectively-collected, multicenter adult spinal deformity (ASD) database.
The aim of this study was to evaluate the rate of patients who accrue catastrophic cost (CC) with ...ASD surgery utilizing direct, actual costs, and determine the feasibility of predicting these outliers.
Cost outliers or surgeries resulting in CC are a major concern for ASD surgery as some question the sustainability of these surgical treatments.
Generalized linear regression models were used to explain the determinants of direct costs. Regression tree and random forest models were used to predict which patients would have CC (>$100,000).
A total of 210 ASD patients were included (mean age of 59.3 years, 83% women). The mean index episode of care direct cost was $70,766 (SD = $24,422). By 90 days and 2 years following surgery, mean direct costs increased to $74,073 and $77,765, respectively. Within 90 days of the index surgery, 11 (5.2%) patients underwent 13 revisions procedures, and by 2 years, 26 (12.4%) patients had undergone 36 revision procedures. The CC threshold at the index surgery and 90-day and 2-year follow-up time points was exceeded by 11.9%, 14.8%, and 19.1% of patients, respectively. Top predictors of cost included number of levels fused, surgeon, surgical approach, interbody fusion (IBF), and length of hospital stay (LOS). At 90 days and 2 years, a total of 80.6% and 64.0% of variance in direct cost, respectively, was explained in the generalized linear regression models. Predictors of CC were number of fused levels, surgical approach, surgeon, IBF, and LOS.
The present study demonstrates that direct cost in ASD surgery can be accurately predicted. Collectively, these findings may not only prove useful for bundled care initiatives, but also may provide insight into means to reduce and better predict cost of ASD surgery outside of bundled payment plans.
3.
Purpose
Anterior approaches are gaining popularity for adult spinal deformity (ASD) surgeries especially with the introduction of hyperlordotic cages and improvement in MIS techniques. Combined ...Approaches provide powerful segmental sagittal correction potential and increase the surface area available for fusion in ASD surgery, both of which would improve overall. This is the first study directly comparing surgical outcomes between combined anterior–posterior approaches and all-posterior approach in a matched ASD population.
Methods
This is a retrospective matched control cohort analysis with substitution using a multicenter prospectively collected ASD data of patients with > 2 year FU. Matching criteria include: age, American Society of Anesthesiologists Score, Lumbar Cobb angle, sagittal deformity (Global tilt) and ODI.
Results
In total, 1024 ASD patients were available for analysis. 29 Combined Approaches patients met inclusion criteria, and only 22 could be matched (1:2 ratio). Preoperative non-matched demographical, clinical, surgical and radiological parameters were comparable between both groups. Combined approaches had longer surgeries (548 mns vs 283) with more blood loss (2850 ml vs 1471) and needed longer ICU stays (74 h vs 27). Despite added morbidity, they had comparable complication rates but with significantly less readmissions (9.1% vs 38.1%) and reoperations (18.2% vs 43.2%) at 2 years. Combined Approaches achieved more individualised and harmonious deformity correction initially. At the 2 years control, Combined Approaches patients reported better outcomes as measured by COMI and SRS scores. This trend was maintained at 3 years.
Conclusion
Despite an increased initial surgical invasiveness, combined approaches seem to achieve more harmonious correction with superior sagittal deformity control; they need fewer revisions and have improved long-term functional outcomes when compared to all-posterior approaches for ASD deformity correction.
Prospective multicenter study of adult spinal deformity (ASD) surgery.
To clarify the effect of ASD surgery on each health-related quality of life (HRQOL) subclass/domain.
For patients with ASD, ...surgery offers superior radiological and HRQOL outcomes compared with nonoperative care. HRQOL may, however, be affected by surgical advantages related to corrective effects, yielding adequate spinopelvic alignment and stability or disadvantages because of long segment fusion.
The study included 170 consecutive patients with ASD from a multicenter database with more than 2-year follow-up period. We analyzed each HRQOL domain/subclass (short form-36 items, Oswestry Disability Index, Scoliosis Research Society-22 SRS-22 questionnaire), and radiographic parameters preoperatively and at 1 and 2 years postoperatively. We divided the patients into two groups each based on lowest instrumented vertebra (LIV; above L5 or S1 to ilium) or surgeon-determined preoperative pathology (idiopathic or degenerative). Improvement rate (%) was calculated as follows: 100 × |pre.-post.|/preoperative points (%) (+, advantages; -, disadvantages).
The scores of all short form-36 items and SRS-22 subclasses improved at 1 and 2 years after surgery, regardless of LIV location and preoperative pathology. Personal care and lifting in Oswestry Disability Index were, however, not improved after 1 year. These disadvantages were correlated to sagittal modifiers of SRS-Schwab classification similar to other HRQOL. The degree of personal care disadvantage mainly depended on LIV location and preoperative pathology. Although personal care improved after 2 years postoperatively, no noticeable improvements in lifting were recorded.
HRQOL subclass analysis indicated two disadvantages of ASD surgery, which were correlated to sagittal radiographic measures. Fusion to the sacrum or ilium greatly restricted the ability to stretch or bend, leading to limited daily activities for at least 1 year postoperatively, although this effect may subside after another year. Consequently, spinal surgeons should note the effect of surgical treatment on each HRQOL domain and counsel patients about the implications of surgery.
4.
A post hoc analysis.
Advances in machine learning (ML) have led to tools offering individualized outcome predictions for adult spinal deformity (ASD). Our objective is to examine the properties of ...these ASD models in a cohort of adult symptomatic lumbar scoliosis (ASLS) patients.
ML algorithms produce patient-specific probabilities of outcomes, including major complication (MC), reoperation (RO), and readmission (RA) in ASD. External validation of these models is needed.
Thirty-nine predictive factors (12 demographic, 9 radiographic, 4 health-related quality of life, 14 surgical) were retrieved and entered into web-based prediction models for MC, unplanned RO, and hospital RA. Calculated probabilities were compared with actual event rates. Discrimination and calibration were analyzed using receiver operative characteristic area under the curve (where 0.5=chance, 1=perfect) and calibration curves (Brier scores, where 0.25=chance, 0=perfect). Ninety-five percent confidence intervals are reported.
A total of 169 of 187 (90%) surgical patients completed 2-year follow up. The observed rate of MCs was 41.4% with model predictions ranging from 13% to 68% (mean: 38.7%). RO was 20.7% with model predictions ranging from 9% to 54% (mean: 30.1%). Hospital RA was 17.2% with model predictions ranging from 13% to 50% (mean: 28.5%). Model classification for all three outcome measures was better than chance for all area under the curve=MC 0.6 (0.5-0.7), RA 0.6 (0.5-0.7), RO 0.6 (0.5-0.7). Calibration was better than chance for all, though best for RA and RO (Brier Score=MC 0.22, RA 0.16, RO 0.17).
ASD prediction models for MC, RA, and RO performed better than chance in a cohort of adult lumbar scoliosis patients, though the homogeneity of ASLS affected calibration and accuracy. Optimization of models require samples with the breadth of outcomes (0%-100%), supporting the need for continued data collection as personalized prediction models may improve decision-making for the patient and surgeon alike.
Introduction
The Global Alignment and Proportion (GAP) score incorporates three domains directly modified with surgery (relative pelvic version–RPV, relative lumbar lordosis—RLL, lumbar distribution ...index—LDI) and one indirectly restored (relative spinopelvic alignment—RSA). We analyzed our surgical realignment performance and the consequences of domain-specific realignment failure on mechanical complications and PROMs.
Materials and methods
From an adult spinal deformity prospective multicenter database, we selected patients: fused to pelvis, upper instrumented vertebra at or above L1, and 2 years of follow-up. Descriptive, univariate and multivariate analyses were employed.
Results
The sample included 333 patients. RLL-6w showed the highest success rate (58.3% aligned), but 16.5% of patients were classified in the “Severe hypolordosis” and “Hyperlordosis” subgroups. RPV-6w was the most challenging to realign, with 51.6% moderate or severe retroversion. Regarding RSA-6w, 21.9% had severe positive malalignment. Correct alignment of RPV-6w (
p
= 0.025) and RSA-6w (
p
= 0.002) proved to be protective factors against the development of mechanical complications. Severe pelvic retroversion (
p
= 0.026) and severe positive malalignment (
p
= 0.007) were risk factors for mechanical complications. RSA-6w “Severe positive malalignment” was associated with less improvement in PROMs: ∆ODI (8.83 vs 17.2;
p
= 0.011), ∆SRS-22 total (0.54 vs 0.87;
p
= 0.007), and ∆SF-36PCS (3.47 vs 7.76;
p
= 0.04); MCID for ODI (37.0 vs 55.5%;
p
= 0.023), and SRS-22 (40.8 vs 60.1%;
p
= 0.015); and PASS for ODI (17.6 vs 31.7%;
p
= 0.047).
Conclusions
RPV was the most underperformed modifiable parameter. Severe pelvic retroversion and severe positive malalignment influenced the occurrence of mechanical complications. Severe positive malalignment affected PROMs improvement.
