Cost-Effectiveness of Surgical Treatment for Adult Spinal Deformity: A Comparison of Dollars per Quality of Life Improvement Across Health Domains

Methodology of economic evaluations in spine surgery: a systematic review and qualitative assessment

OBJECTIVES

The present study is a systematic review conducted as part of a methodological approach to develop evidence-based recommendations for economic evaluations in spine surgery. The aim of this systematic review is to evaluate the methodology and quality of currently available clinical cost-effectiveness studies in spine surgery.

STUDY DESIGN

Systematic literature review.

DATA SOURCES

PubMed, Web of Science, Embase, Cochrane, Cumulative Index to Nursing and Allied Health Literature, EconLit and The National Institute for Health Research Economic Evaluation Database were searched through 8 December 2022.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies were included if they met all of the following eligibility criteria: (1) spine surgery, (2) the study cost-effectiveness and (3) clinical study. Model-based studies were excluded.

DATA EXTRACTION AND SYNTHESIS

The following data items were extracted and evaluated: pathology, number of participants, intervention(s), year, country, study design, time horizon, comparator(s), utility measurement, effectivity measurement, costs measured, perspective, main result and study quality.

RESULTS

130 economic evaluations were included. Seventy-four of these studies were retrospective studies. The majority of the studies had a time horizon shorter than 2 years. Utility measures varied between the EuroQol 5 dimensions and variations of the Short-Form Health Survey. Effect measures varied widely between Visual Analogue Scale for pain, Neck Disability Index, Oswestry Disability Index, reoperation rates and adverse events. All studies included direct costs from a healthcare perspective. Indirect costs were included in 47 studies. Total Consensus Health Economic Criteria scores ranged from 2 to 18, with a mean score of 12.0 over all 130 studies.

CONCLUSIONS

The comparability of economic evaluations in spine surgery is extremely low due to different study designs, follow-up duration and outcome measurements such as utility, effectiveness and costs. This illustrates the need for uniformity in conducting and reporting economic evaluations in spine surgery.

Outcomes of operative treatment for adult spinal deformity: a prospective multicenter assessment with mean 4-year follow-up

OBJECTIVE

The current literature has primarily focused on the 2-year outcomes of operative adult spinal deformity (ASD) treatment. Longer term durability is important given the invasiveness, complications, and costs of these procedures. The aim of this study was to assess minimum 3-year outcomes and complications of ASD surgery.

METHODS

Operatively treated ASD patients were assessed at baseline, follow-up, and through mailings. Patient-reported outcome measures (PROMs) included scores on the Oswestry Disability Index (ODI), Scoliosis Research Society-22r (SRS-22r) questionnaire, mental component summary (MCS) and physical component summary (PCS) of the SF-36, and numeric rating scale (NRS) for back and leg pain. Complications were classified as perioperative (≤ 90 days), delayed (90 days to 2 years), and long term (≥ 2 years). Analyses focused on patients with minimum 3-year follow-up.

RESULTS

Of 569 patients, 427 (75%) with minimum 3-year follow-up (mean ± SD [range] 4.1 ± 1.1 [3.0-9.6] years) had a mean age of 60.8 years and 75% were women. Operative treatment included a posterior approach for 426 patients (99%), with a mean ± SD 12 ± 4 fusion levels. Anterior lumbar interbody fusion was performed in 35 (8%) patients, and 89 (21%) underwent 3-column osteotomy. All PROMs improved significantly from baseline to last follow-up, including scores on ODI (45.4 to 30.5), PCS (31.0 to 38.5), MCS (45.3 to 50.6), SRS-22r total (2.7 to 3.6), SRS-22r activity (2.8 to 3.5), SRS-22r pain (2.3 to 3.4), SRS-22r appearance (2.4 to 3.5), SRS-22r mental (3.4 to 3.7), SRS-22r satisfaction (2.7 to 4.1), NRS for back pain (7.1 to 3.8), and NRS for leg pain (4.8 to 3.0) (all p < 0.001). Degradations in some outcome measures were observed between the 2-year and last follow-up evaluations, but the magnitudes of these degradations were modest and arguably not clinically significant. Overall, 277 (65%) patients had at least 1 complication, including 185 (43%) perioperative, 118 (27%) delayed, and 56 (13%) long term. Notably, the 142 patients who did not achieve 3-year follow-up were similar to the study patients in terms of demographic characteristics, deformities, and baseline PROMs and had similar rates and types of complications.

CONCLUSIONS

This prospective multicenter analysis demonstrated that operative ASD treatment provided significant improvement of health-related quality of life at minimum 3-year follow-up (mean 4.1 years), suggesting that the benefits of surgery for ASD remain durable at longer follow-up. These findings should prove useful for counseling, cost-effectiveness assessments, and efforts to improve the safety of care.

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.

The Impact of Comorbid Mental Health Disorders on Complications Following Adult Spinal Deformity Surgery With Minimum 2-Year Surveillance

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

To compare long-term outcomes between patients with and without mental health comorbidities who are undergoing surgery for adult spinal deformity (ASD).

SUMMARY OF BACKGROUND DATA

Recent literature reveals that one in three patients admitted for surgical treatment for ASD has comorbid mental health disorder. Currently, impacts of baseline mental health status on long-term outcomes following ASD surgery have not been thoroughly investigated.

METHODS

Patients admitted from 2009 to 2013 with diagnoses of ASD who underwent more than or equal to 4-level thoracolumbar fusion with minimum 2-year follow-up were retrospectively reviewed using New York State's Statewide Planning and Research Cooperative System (SPARCS). Patients were stratified by fusion length (short: 4-8-level; long: ≥9 level). Patients with comorbid mental health disorder (MHD) at time of admission were selected for analysis (MHD) and compared against those without MHD (no-MHD). Univariate analysis compared demographics, complications, readmissions, and revisions between cohorts for each fusion length. Multivariate binary logistic regression models identified independent predictors of outcomes (covariates: fusion length, age, female sex, and Deyo score).

RESULTS

Six thousand twenty patients (MHD: n = 1631; no-MHD: n = 4389) met inclusion criteria. Mental health diagnoses included disorders of depression (59.0%), sleep (28.0%), anxiety (24.0%), and stress (2.3%). At 2-year follow-up, MHD patients with short fusion had significantly higher complication rates (P = 0.001). MHD patients with short or long fusion also had significantly higher rates of any readmission and revision (all P ≤ 0.002). Regression modeling revealed that comorbid MHD was a significant predictor of any complication (odds ratio [OR]: 1.17, P = 0.01) and readmission (OR: 1.32, P < 0.001). MHD was the strongest predictor of any revision (OR: 1.56, P < 0.001). Long fusion most strongly predicted any complication (OR: 1.87, P < 0.001).

CONCLUSION

ASD patients with comorbid depressive, sleep, anxiety, and stress disorders were more likely to experience surgical complications and revision at minimum of 2 years following spinal fusion surgery. Proper patient counseling and psychological screening/support is recommended to complement ASD treatment.

LEVEL OF EVIDENCE

3.

Novel Index to Quantify the Risk of Surgery in the Setting of Adult Spinal Deformity: A Study on 10,912 Patients From the Nationwide Inpatient Sample

STUDY DESIGN

Retrospective review of the Nationwide Inpatient Sample from 2001 to 2010, a prospectively collected national database.

OBJECTIVE

Structure an index to quantify adult spinal deformity (ASD) surgical risk based on risk factors for medical complications, surgical complications, revisions (R), mortality (M) rates, and length of hospital stay.

SUMMARY OF BACKGROUND DATA

Evidence supporting ASD surgery cost-effectiveness and anticipating surgical risk is critical to evaluate the risk/benefit balance of such treatment for patients.

MATERIALS AND METHODS

Discharges ages 25+, 4+ levels fused, diagnoses specific for scoliosis, and refusions. Five multivariate models determined independent risk factors that increased the risk of ≥1 for medical complications, surgical complications, R, M, and length of hospital stay. Models controlled for age, sex, race, revision status, surgical approach, levels fused, and osteotomy utilization. Odds ratios (ORs) were weighted using Nationwide Inpatient Sample weight files and based on their predictive category: 2 times for revision predictors and 4 times for mortality predictors. Predictors with OR≥1.5 were considered clinically relevant. Fifty points were distributed among the predictors based on their accumulative OR to establish a risk index.

RESULTS

A total of 10,912 ASD discharges were identified (mean age: 62 y; 73% females; 14% revision cases). The structured risk index incorporated the following factors based on accumulative ORs: pulmonary circulation disorder (42.05), drug abuse (21.86), congestive heart failure (15.25), neurological disorder (17.31), alcohol abuse (13.24), renal failure (11.64), age>65 (12.28), coagulopathy (11.65), level +9 (6.7), revision (3.35), and osteotomy (3). These risk factors were scored: 14, 7, 5, 5, 4, 4, 4, 4, 2, 1, 1, respectively. Three risk thresholds were proposed: mild (0-10), moderate (10-20), severe >20/50 points.

CONCLUSIONS

This study proposes an index to quantify the possible risk of morbidity before ASD surgery that will help patients, health insurance companies, and socioeconomic studies in assessing surgical risk/benefits.

LEVEL OF EVIDENCE

Level III.

Predicting Extended Length of Hospital Stay in an Adult Spinal Deformity Surgical Population

STUDY DESIGN

A retrospective review of a prospective multicenter database.

OBJECTIVE

The aim of this study was to identify variables associated with extended length of stay (ExtLOS) and this impact on health-related quality of life (HRQoL) scores in adult spinal deformity (ASD) patients.

SUMMARY OF BACKGROUND DATA

ASD surgery is complex and associated with complications including extLOS. Although variables contributing to extLOS have been considered, specific complications and pre-disposing factors among ASD surgical patients remain to be investigated.

INCLUSION CRITERIA

ASD surgical patients (age >18 years, scoliosis ≥20°, sagittal vertical axis ≥5 cm, pelvic tilt ≥25°, and/or thoracic kyphosis >60°) with complete demographic, radiographic, and HRQoL data at baseline, 6 weeks, and 2 years postoperative. ExtLOS was based on 75th percentile (≥9 days). Univariate and multivariate analyses identified predictors and evaluated effects on outcomes. Repeated-measures mixed models analyzed impact of ExtLOS on HRQoL [Oswestry Disability Index; Short Form-36 physical component summary/mental component summary; SRS22r Activity (AC), Pain (P), Appearance (AP), Satisfaction (S), Mental (M) and Total (T)].

RESULTS

Three hundred eighty patients met inclusion criteria: 105 (27.6%) had extLOS (≥9 days) and 275 (72.4%) did not. Average LOS was 8 days (range: 1-30 days). Age [odds ratio (OR) 1.04], no. of levels fused (OR 1.12), no. of infections (OR 2.29), no. of neurologic complications (OR 2.51), Charlson Comorbidity Index Score (CCI) predicted ExtLOS (OR 3.92), and no. of intraop complications predicted ExtLOS (OR 3.56). ExtLOS patients had more intracardiopulmonary (pleural effusion: 1.9% vs. 0%) and operative complications (dural tear: 13.3% vs. 5.1%; excessive blood loss: 18% vs. 5.8%) (P < 0.022). At 2 years, both groups of patients experienced an overall improvement in all HRQoL scores (P < 0.001). ExtLOS patients had significantly less overall improvement in all HRQoLs (P < 0.01) except for MCS (P = 0.17) and SRS M (P = 0.08).

CONCLUSION

Extended LOS of ASD patients is affected by comorbidities (higher CCI) and number of intraoperative, but not peri-operative, complications. All patients improved overall in HRQoL scores, but extended LOS patients improved less overall at 2 years in comparison.

LEVEL OF EVIDENCE

3.