The Influence of Diagnosis, Age, and Gender on Surgical Outcomes in Patients With Adult Spinal Deformity

Calculation of the minimal clinically important difference in operated patients with adult spine deformity: advantages of the ROC method and significance of prevalence in threshold selection

PURPOSE

The Minimal Clinically Important Difference (MCID) is crucial to evaluate management outcomes, but different thresholds have been obtained in different works. Part of this variability is due to measurement error and influence of the database, both essential for calculating the MCID. The aim of this study was to introduce the association of the ROC method in the anchor-based MCID calculation for ODI, SRS-22r, and SF-36, to objectively set the threshold for the anchor-based MCID in an adult spine deformity (ASD) population.

METHODS

Multicentric study based on a prospective database of consecutively operated ASD patients. An anchor question was used to assess patients' quality of life after surgery. Different approaches were used to calculate the MCID and then compared: SEM (Standard Error of Measurement), MDC (Minimal Detectable Change), and anchor-based MCID with ROC method.

RESULTS

516 patients were included. Those who responded with 6 and 7 to the anchor question were considered improved. The MCID ranges obtained with the ROC method exhibited the lowest variability. Prediction error rates ranged from 31% (SRS-22r) to 41% (SF-36 MCS). The MCID ranges spanned between 12 and 15 for ODI, 0.6 and 0.73 for SRS-22r, 6.62 and 7.41 for SF-36 PCS, and between 2.69 and 5.63 for SF-36 MCS.

CONCLUSION

The ROC method proposes an MCID range with error rate, and can objectively determine the threshold for distinguishing improved and non-improved patients. As the MCID correlates with the utilized database and error of measurement, each study should compute its own MCID for each PROM to allow comparison among different publications.

LEVEL OF EVIDENCE

II.

Can Baseline Disability Predict Outcomes in Adult Spinal Deformity Surgery?

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVE

To assess if there is a threshold of baseline disability beyond which the patient-reported outcomes after surgical correction of adult spinal deformity (ASD) are adversely impacted.

BACKGROUND

Patient-reported outcomes vary after correction of adult spinal deformity, even when patients are optimally realigned. There is a paucity of literature examining the impact of baseline disability on patient-reported outcomes in ASD.

METHODS

Patients with baseline (BL) and two-year data were included. Disability was ranked according to BL Oswestry Disability Index (ODI) into quintiles: Q1 (lowest ODI score) to Q5 (highest ODI score). Adjusted logistic regression analyses evaluated the likelihood of reaching ≥1 MCID in Scoliosis Research Society Outcomes Questionnaire (SRS-22) Pain, SRS-22 Activity, and Short Form-36 physical component summary at two years across disability groups Q1-Q4 with respect to Q5. Sensitivity tests were performed, excluding patients with any "0" Schwab modifiers at BL.

RESULTS

Compared with patients in Q5, the odds of reaching MCID in SRS-22 Pain at 2Y were significantly higher for those in Q1 (OR: 3.771), Q2 (OR: 3.006), and Q3 (OR: 2.897), all P <0.021. Similarly, compared with patients in Q5, the odds of reaching MCID in SRS-22 Activity at two years were significantly higher for those in Q2 (OR: 3.454) and Q3 (OR: 2.801), both P <0.02. Lastly, compared with patients in Q5, odds of reaching MCID in Short Form-36 physical component summary at two years were significantly higher for patients in Q1 (OR: 5.350), Q2 (OR: 4.795), and Q3 (OR: 6.229), all P <0.004.

CONCLUSIONS

This study found that patients presenting with moderate disability at BL (ODI<40) consistently surpassed health-related quality of life outcomes as compared with those presenting with greater levels of disability. We propose that a baseline ODI of 40 represents a disability threshold within which operative inte rvention maximizes patient-reported outcomes. Furthermore, delaying the intervention until patients progress to severe disability may limit the benefits of surgical correction in ASD patients.

LEVEL OF EVIDENCE

3.

Correlation Between Sagittal Balance and Mechanical Distal Junctional Failure in Degenerative Pathology of the Spine: A Retrospective Analysis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

This study aimed to investigate the failure of the caudal end of lumbar posterior fixation in terms of pre-operative and post-operative spinopelvic parameters, correction performed, demographic and clinical data.

METHODS

The lumbar, thoraco-lumbar and lumbo-sacral posterior fixations performed with pedicle screws and rods in 2017-2019 were retrospectively analyzed. As 81% failures occurred within 4 years, an observational period of 4 years was chosen. The revision surgeries due to the failure in the caudal end were collected in the junctional group. Fixations which have not failed were gathered in the control group. The main spinopelvic parameters were measured for each patient on standing lateral radiographs with the software Surgimap. Demographic and clinical data were extracted for both groups.

RESULTS

Among the 457 patients who met the inclusion criteria, the junctional group included 101 patients, who required a revision surgery. The control group collected 356 primary fixations. The two most common causes of revision surgeries were screws pullout (57 cases) and rod breakage (53 cases). SVA, PT, LL, PI-LL and TPA differed significantly between the two groups (P = .021 for LL, P < .0001 for all the others). The interaction between the two groups and the pre-operative and post-operative conditions was significant for PT, SS, LL, TK, PI-LL and TPA (P < .005). Sex and BMI did not affect the failure onset.

CONCLUSIONS

Mechanical failure is more likely to occur in patients older than 40 years with a thoraco-lumbar fixation where PT, PI-LL and TPA were not properly restored.

Sex and gender determinants following spinal fusion surgery: A systematic review of clinical data

In the last decade, numerous studies analyzed and described the surgical outcomes in male and female patients submitted to orthopedic surgery. Although this, the impact of sex/gender on spinal fusion surgery clinical outcomes is still poorly defined. This review systematically maps and synthesizes the scientific literature on sex/gender differences in postoperative outcomes for patients undergoing spinal fusion surgery. The search was performed in PubMed, Scopus, and Web of Science in the last 22 years. Clinical studies evaluating potential sex/gender differences in postoperative outcomes and/or complications, as primary or secondary aim, were included and analyzed. Out of the 1,885 records screened, 47 studies were included. These studies comprised a total of 1,158,555 patients (51.31% female; 48.69% male). About 77% of the analyzed studies reported sex/gender-related differences in postoperative outcomes. Most studies treated patients for lumbar degenerative diseases and more than 55% of them reported a worse postoperative outcome in female patients in terms of pain, disability, health-related quality of life questionnaires, and complications. Differently, a significant heterogeneity across studies on patients treated for cervical and sacral degenerative diseases as well as for spinal deformity and traumatic spinal fracture prevented the understanding of specific sex/gender differences after spinal fusion surgery. Despite this, the present review highlighted those female patients treated for lumbar degenerative spine diseases could require more clinical awareness during postoperative care. The understanding of how sex/gender differences can really affect clinical outcomes after spinal fusion surgeries is mandatory for all spinal pathological conditions to drive clinical research toward oriented and personalized protocols.

Failure in Adult Spinal Deformity Surgery: A Comprehensive Review of Current Rates, Mechanisms, and Prevention Strategies

STUDY DESIGN

Literature review.

OBJECTIVE

The aim of this review is to summarize recent literature on adult spinal deformity (ASD) treatment failure as well as prevention strategies for these failure modes.

SUMMARY OF BACKGROUND DATA

There is substantial evidence that ASD surgery can provide significant clinical benefits to patients. The volume of ASD surgery is increasing, and significantly more complex procedures are being performed, especially in the aging population with multiple comorbidities. Although there is potential for significant improvements in pain and disability with ASD surgery, these procedures continue to be associated with major complications and even outright failure.

METHODS

A systematic search of the PubMed database was performed for articles relevant to failure after ASD surgery. Institutional review board approval was not needed.

RESULTS

Failure and the potential need for revision surgery generally fall into 1 of 4 well-defined phenotypes: clinical failure, radiographic failure, the need for reoperation, and lack of cost-effectiveness. Revision surgery rates remain relatively high, challenging the overall cost-effectiveness of these procedures.

CONCLUSION

By consolidating the key evidence regarding failure, further research and innovation may be stimulated with the goal of significantly improving the safety and cost-effectiveness of ASD surgery.

Variation of Minimum Clinically Important Difference by Age, Gender, Baseline Disability, and Change of Direction in Adult Spinal Deformity Population: Is It a Constant Value?

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Decision Analysis in Quest of the Ideal Treatment in Adult Spinal Deformity Adjusted for Minimum Clinically Important Difference

BACKGROUND

Surgery appears to yield better results in adult spinal deformity treatment when fixed minimum clinically important difference values are used to define success. Our objective was to analyze utilities and improvement provided by surgical versus nonsurgical treatment at 2 years using Oswestry Disability Index with treatment-specific minimum clinically important difference values.

METHODS

From a multicenter database including 1452 patients, 698 with 2 years of follow-up were analyzed. Mean age of patients was 50.95 ± 19.44 years; 580 patients were women, and 118 were men. The surgical group comprised 369 patients, and the nonsurgical group comprised 329 patients. The surgical group was subcategorized into no complications (192 patients), minor complications (97 patients) and major complications (80 patients) groups to analyze the effect of complications on results. Minimum clinically important differences using Oswestry Disability Index were 14.31, 14.96, and 2.48 for overall, surgical, and nonsurgical groups. Utilities were calculated by visual analog scale mapping.

RESULTS

Surgical treatment provided higher utility (0.583) than nonsurgical treatment (0.549) that was sensitive to complications, being 0.634, 0.564, and 0.497 in no, minor, and major complications. Probabilities of improvement, unchanged, and deterioration were 38.3%, 39.2%, and 22.5% for surgical treatment and 39.4%, 10.5%, and 50.1% for nonsurgical treatment. Improvement in the surgical group was also sensitive to complications with rates of 40.1%, 39.3%, and 33.3%.

CONCLUSIONS

Our results suggest that surgical treatment has less disease burden and less chance of deterioration, but equal chances for improvement at 2 years of follow-up. As it appears to be a better modality in the absence of complications, future efforts need be directed to decreasing the complication rates.

Effect modifiers for patient-reported outcomes in operatively and nonoperatively treated patients with adult symptomatic lumbar scoliosis: a combined analysis of randomized and observational cohorts

OBJECTIVE

Adult symptomatic lumbar scoliosis (ASLS) is a common and disabling condition. The ASLS-1 was a multicenter, dual-arm study (with randomized and observational cohorts) examining operative and nonoperative care on health-related quality of life in ASLS. An aim of ASLS-1 was to determine patient and radiographic factors that modify the effect of operative treatment for ASLS.

METHODS

Patients 40-80 years old with ASLS were enrolled in randomized and observational cohorts at 9 North American centers. Primary outcomes were the differences in mean change from baseline to 2-year follow-up for the SRS-22 subscore (SRS-SS) and the Oswestry Disability Index (ODI). Analyses were performed using an as-treated approach with combined cohorts. Factors examined were prespecified or determined using regression tree analysis. For each potential effect modifier, subgroups were created using clinically relevant cutoffs or via regression trees. Estimates of within-group and between-group change were compared using generalized linear mixed models. An effect modifier was defined as a treatment effect difference greater than the minimal detectable measurement difference for both SRS-SS (0.4) and ODI (7).

RESULTS

Two hundred eighty-six patients were enrolled and 256 (90%) completed 2-year follow-up; 171 received operative treatment and 115 received nonoperative treatment. Surgery was superior to nonoperative care for all effect subgroups considered, with the exception of those with nearly normal pelvic incidence-lumbar lordosis (PI-LL) match (≤ 11°). Male patients and patients with more (> 11°) PI-LL mismatch at baseline had greater operative treatment effects on both the SRS-SS and ODI compared to nonoperative treatment. No other radiographic subgroups were associated with treatment effects. High BMI, lower socioeconomic status, and poor mental health were not related to worse outcomes.

CONCLUSIONS

Numerous factors previously related to poor outcomes with surgery, such as low mental health, lower socioeconomic status, and high BMI, were not related to outcomes in ASLS in this exploratory analysis. Those patients with higher PI-LL mismatch did improve more with surgery than those with normal alignment. On average, none of the factors considered were associated with a worse outcome with operative treatment versus nonoperative treatment. These findings may guide future prospective analyses of factors related to outcomes in ASLS care.