Increasing Cost Efficiency in Adult Spinal Deformity Surgery: Identifying Predictors of Lower Total Costs

Who benefits from home-based exercise for adult spinal deformity? A prospective multicenter study on clinical and radiographic predictors

PURPOSE

The prevalence of adult spinal deformity (ASD) is expected to exceed 60 million by 2050 due to an aging population and increased life expectancy. Despite advances in surgery, high complication rates and the economic burden highlight the need for effective non-surgical treatments. This study assesses the "Koshimagari Exercise," a self-exercise program for ASD patients, and aims to develop a classification system to identify those who would benefit most.

METHODS

A prospective cohort study was conducted across 13 facilities, enrolling 144 participants from December 2020 to June 2022. The inclusion criteria were adults aged 50-80 years with chronic low back pain due to spinal deformities. Participants attended weekly physiotherapist-led exercise sessions and performed self-exercises at home three times a week, focusing on flexibility, functional improvement, trunk and back muscle strengthening, motor learning, and pain control. The primary outcome was the change in the Oswestry Disability Index (ODI) from baseline to 6 months post-intervention, with a 12-month follow-up. Clinical evaluations included health-related quality of life (HRQOL) assessments with ODI and EuroQol-5 Dimensions (EQ-5D), spinal alignment radiography, and magnetic resonance imaging of the paravertebral muscle (PVM) cross-sectional area.

RESULTS

Of the 130 participants who provided written informed consent, 98 completed the 6-month follow-up. The study found that 42% of patients achieved a minimum clinically important difference (MCID) in ODI, with significant improvements in EQ-5D scores and LBP from baseline. Patients who achieved MCID had lower baseline body mass index and EQ-5D scores, and higher baseline ODI scores compared to those who did not. Logistic regression identified three significant predictors of MCID achievement: L4/S1 angle, the difference between standing and supine thoracolumbar kyphosis (ΔTLK), and the relative cross-sectional area (rCSA) of the PVM at L4/5. Based on these findings, a classification system was developed, dividing patients into Self-Exercise-Friendly and Self-Exercise-Limited groups, with a significant difference in ODI improvement observed between these groups at 6 months post-intervention.

CONCLUSION

The "Koshimagari Exercise," a novel self-exercise program for ASD, achieved an MCID in the ODI for 42% of patients. The classification system, incorporating L4/S1 angle, ΔTLK, and L4/5 rCSA, is associated with improvements in HRQOL and may help identify patients who are more likely to benefit from this home-based exercise program.

Prediction of primary admission total charges following cervical disc arthroplasty utilizing machine learning

BACKGROUND CONTEXT

Cervical disc arthroplasty (CDA) has become an increasingly popular alternative to anterior cervical discectomy and fusion, offering benefits such as motion preservation and reduced risk of adjacent segment disease. Despite its advantages, understanding the economic implications associated with varying patient and hospital factors remains critical.

PURPOSE

To evaluate how hospital size, geographic region, and patient-specific variables influence charges associated with the primary admission period following CDA.

STUDY DESIGN

A retrospective analysis using machine learning models to predict and analyze charge factors associated with CDA.

PATIENT SAMPLE

Data from the National Inpatient Sample (NIS) database from 2016 to 2020 was used, focusing on patients undergoing CDA.

OUTCOME MEASURES

The primary outcome was total charge associated with the primary admission for CDA, analyzed against patient demographics, hospital characteristics, and regional economic conditions.

METHODS

Multivariate linear regression and machine learning algorithms including logistic regression, random forest, and gradient boosting trees were employed to assess their predictive power on charge outcomes. Statistical significance was set at the 0.003 level after applying a Bonferroni correction.

RESULTS

The analysis included 3,772 eligible CDA cases. Major predictors of charge identified were hospital size and ownership type, with large and privately owned hospitals associated with higher charges (p<.001). The Western region of the U.S. also showed significantly higher charges compared to the Northeast (p<.001). The gradient boosting trees model showed the highest accuracy (AUC=85.6%). Length of stay and wage index were significant charge drivers, with each additional inpatient day increasing charges significantly (p<.001) and higher wage index regions correlating with increased charges (p<.001).

CONCLUSIONS

Hospital size, geographic region, and specific patient demographics significantly influence the charges of CDA. Machine learning models proved effective in predicting these charges, suggesting that they could be instrumental in guiding economic decision-making in spine surgery. Future efforts should aim to incorporate these models into broader clinical practice to optimize healthcare spending and enhance patient care outcomes.

Thoracolumbar fusions for adult lumbar deformity show superior QALY gain and lower costs compared with upper thoracic fusions

PURPOSE

Adult spinal deformity (ASD) patients with sagittal plane deformity (N) or structural lumbar/thoraco-lumbar (TL) curves can be treated with fusions stopping at the TL junction or extending to the upper thoracic (UT) spine. This study evaluates the impact on cost/cumulative quality-adjusted life year (QALY) in patients treated with TL vs UT fusion.

METHODS

ASD patients with > 4-level fusion and 2-year follow-up were included. Index and total episode-of-care costs were estimated using average itemized direct costs obtained from hospital records. Cumulative QALY gained were calculated from preoperative to 2-year postoperative change in Short Form Six-Dimension (SF-6D) scores. The TL and UT groups comprised patients with upper instrumented vertebrae (UIV) at T9-T12 and T2-T5, respectively.

RESULTS

Of 566 patients with type N or L curves, mean age was 63.2 ± 12.1 years, 72% were female and 93% Caucasians. Patients in the TL group had better sagittal vertical axis (7.3 ± 6.9 vs. 9.2 ± 8.1 cm, p = 0.01), lower surgical invasiveness (- 30; p < 0.001), and shorter OR time (- 35 min; p = 0.01). Index and total costs were 20% lower in the TL than in the UT group (p < 0.001). Cost/QALY was 65% lower (492,174.6 vs. 963,391.4), and 2-year QALY gain was 40% higher, in the TL than UT group (0.15 vs. 0.10; p = 0.02). Multivariate model showed TL fusions had lower total cost (p = 0.001) and higher QALY gain (p = 0.03) than UT fusions.

CONCLUSION

In Schwab type N or L curves, TL fusions showed lower 2-year cost and improved QALY gain without increased reoperation rates or length of stay than UT fusions.

LEVEL OF EVIDENCE

III.

Factors Associated With the Maintenance of Cost-effectiveness at Five Years in Adult Spinal Deformity Corrective Surgery

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

To evaluate factors associated with the long-term durability of cost-effectiveness (CE) in ASD patients.

BACKGROUND

A substantial increase in costs associated with the surgical treatment for adult spinal deformity (ASD) has given precedence to scrutinize the value and utility it provides.

METHODS

We included 327 operative ASD patients with five-year (5 yr) follow-up. Published methods were used to determine costs based on CMS.gov definitions and were based on the average DRG reimbursement rates. The utility was calculated using quality-adjusted life-years (QALY) utilizing the Oswestry Disability Index (ODI) converted to Short-Form Six-Dimension (SF-6D), with a 3% discount applied for its decline in life expectancy. The CE threshold of $150,000 was used for primary analysis.

RESULTS

Major and minor complication rates were 11% and 47%, respectively, with 26% undergoing reoperation by five years. The mean cost associated with surgery was $91,095±$47,003, with a utility gain of 0.091±0.086 at one years, QALY gained at 2 years of 0.171±0.183, and at five years of 0.42±0.43. The cost per QALY at two years was $414,885, which decreased to $142,058 at five years.With the threshold of $150,000 for CE, 19% met CE at two years and 56% at five years. In those in which revision was avoided, 87% met cumulative CE till life expectancy. Controlling analysis depicted higher baseline CCI and pelvic tilt (PT) to be the strongest predictors for not maintaining durable CE to five years [CCI OR: 1.821 (1.159-2.862), P =0.009] [PT OR: 1.079 (1.007-1.155), P =0.030].

CONCLUSIONS

Most patients achieved cost-effectiveness after four years postoperatively, with 56% meeting at five years postoperatively. When revision was avoided, 87% of patients met cumulative cost-effectiveness till life expectancy. Mechanical complications were predictive of failure to achieve cost-effectiveness at two years, while comorbidity burden and medical complications were at five years.

Inflation-adjusted medicare physician reimbursement for adult spinal deformity surgery substantially declined from 2002 to 2020

PURPOSE

Physician fees for orthopaedic surgeons by the Centers for Medicare and Medicaid Services (CMS) are increasingly scrutinized. The present retrospective review aims to assess whether adult spinal deformity (ASD) surgeries are properly valued for Medicare reimbursement.

METHODS

Current Procedural Terminology (CPT) codes related to posterior fusion of spinal deformity of ≤ 6, 7-12, and ≥ 13 vertebral levels, as well as additional arthrodesis and osteotomy levels, were assessed for (1) Compound annual growth rate (CAGR) from 2002 to 2020, calculated using physician fee data from the CMS Physician Fee Schedule Look-Up Tool; and (2) work relative value units (RVUs) per operative minute, using data from the National Surgical Quality Improvement Program.

RESULTS

From 2002 to 2020, all CPT codes for ASD surgery had negative inflation-adjusted CAGRs (range, - 18.49% to - 27.66%). Mean physician fees for spinal fusion declined by 26.02% (CAGR, - 1.66%) in ≤ 6-level fusion, 27.91% (CAGR, - 1.80%) in 7- to 12-level fusion, and 28.25% (CAGR, - 1.83%) ≥ 13-level fusion. Fees for both 7-12 (P < 0.00001) and ≥ 13 levels (P < 0.00001) declined more than those for fusion of ≤ 6 vertebral levels. RVU per minute was lower for 7- to 12-level and ≥ 13-level (P < 0.00001 for both) ASD surgeries than for ≤ 6-level.

CONCLUSIONS

Reimbursement for ASD surgery declined overall. CAGR for fusions of ≥ 7 levels were lower than those for fusions of ≤ 6 levels. For 2012-2018, ≥ 7-level fusions had lower RVU per minute than ≤ 6-level fusions. Revaluation of Medicare reimbursement for longer-level ASD surgeries may be warranted.

LEVEL OF EVIDENCE

III.

How much are patients willing to pay for spine surgery? An evaluation of attitudes toward out-of-pocket expenses and cost-reducing measures

BACKGROUND CONTEXT

With rising healthcare expenditures in the United States, patients and providers are searching to maintain quality while reducing costs.

PURPOSE

The aim of this study was to investigate patient willingness to pay for anterior cervical discectomy and fusion (ACDF), degenerative lumbar spinal fusions (LF), and adult spine deformity (ASD) surgery.

STUDY DESIGN/SETTING

A survey was developed and distributed to anonymous respondents through Amazon Mechanical Turk (MTurk).

METHODS

The survey introduced 3 procedures: ACDF, LF, and ASD surgery. Respondents were asked sequentially if they would pay at each increasing price option. Respondents were then presented with various cost-saving methods and asked to select the options that made them most uncomfortable, even if those would save them out-of-pocket costs.

RESULTS

In total, 979 of 1,172 total responses (84%) were retained for analysis. The average age was 36.2 years and 44% of participants reported a household income of $50,000 to 100,000. A total of 63% used Medicare and 13% used Medicaid. A total of 40% stated they had high levels of financial stress. A total of 30.1% of participants were willing to undergo an ACDF, 30.3% were willing to undergo a LF, and 29.6% were willing to undergo ASD surgery for the cost of $3,000 (p=.98). Regression demonstrated that for ACDF surgery, a $100 increase in price resulted in a 2.1% decrease in willingness to pay. This is comparable to degenerative LF surgery (1.8% decrease), and ASD surgery (2%). When asked which cost-saving measures participants were least comfortable with for ACDF surgery, 60% stated "Use of the older generation implants/devices" (LF: 51%, ASD: 60%,), 61% stated "Having the surgery performed at a community hospital instead of at a major academic center" (LF: 49%, ASD: 56%), and 55% stated "Administration of anesthesia by a nurse anesthetist" (LF: 48.01%, ASD: 55%). Conversely, 36% of ACDF patients were uncomfortable with a "Video/telephone postoperative visit" to cut costs (LF: 51%, ASD: 39%).

CONCLUSIONS

Patients are unwilling to contribute larger copays for adult spinal deformity correction than for ACDF and degenerative lumbar spine surgery, despite significantly higher procedural costs and case complexity/invasiveness. Patients were most uncomfortable forfeiting newer generation implants, receiving the operation at a community rather than an academic center, and receiving care by physician extenders. Conversely, patients were more willing to convert postoperative visits to telehealth and forgo neuromonitoring, indicating a potentially poor understanding of which cost-saving measures may be implemented without increasing the risk of complications.

Are We Focused on the Wrong Early Postoperative Quality Metrics? Optimal Realignment Outweighs Perioperative Risk in Adult Spinal Deformity Surgery

BACKGROUND

While reimbursement is centered on 90-day outcomes, many patients may still achieve optimal, long-term outcomes following adult spinal deformity (ASD) surgery despite transient short-term complications.

OBJECTIVE

Compare long-term clinical success and cost-utility between patients achieving optimal realignment and suboptimally aligned peers.

STUDY DESIGN/SETTING

Retrospective cohort study of a prospectively collected multicenter database.

METHODS

ASD patients with two-year (2Y) data included. Groups were propensity score matched (PSM) for age, frailty, body mass index (BMI), Charlson Comorbidity Index (CCI), and baseline deformity. Optimal radiographic criteria are defined as meeting low deformity in all three (Scoliosis Research Society) SRS-Schwab parameters or being proportioned in Global Alignment and Proportionality (GAP). Cost-per-QALY was calculated for each time point. Multivariable logistic regression analysis and ANCOVA (analysis of covariance) adjusting for baseline disability and deformity (pelvic incidence (PI), pelvic incidence minus lumbar lordosis (PI-LL)) were used to determine the significance of surgical details, complications, clinical outcomes, and cost-utility.

RESULTS

A total of 930 patients were considered. Following PSM, 253 "optimal" (O) and 253 "not optimal" (NO) patients were assessed. The O group underwent more invasive procedures and had more levels fused. Analysis of complications by two years showed that the O group suffered less overall major (38% vs. 52%, p = 0.021) and major mechanical complications (12% vs. 22%, p = 0.002), and less reoperations (23% vs. 33%, p = 0.008). Adjusted analysis revealed O patients more often met MCID (minimal clinically important difference) in SF-36 PCS, SRS-22 Pain, and Appearance. Cost-utility-adjusted analysis determined that the O group generated better cost-utility by one year and maintained lower overall cost and costs per QALY (both p < 0.001) at two years.

CONCLUSIONS

Fewer late complications (mechanical and reoperations) are seen in optimally aligned patients, leading to better long-term cost-utility overall. Therefore, the current focus on avoiding short-term complications may be counterproductive, as achieving optimal surgical correction is critical for long-term success.

Association of frailty with healthcare resource utilization after open thoracic/thoracolumbar posterior spinal fusion for adult spinal deformity

PURPOSE

The Hospital Frailty Risk Score (HFRS) is a frailty-identifying metric developed using ICD-10-CM codes. While other studies have examined frailty in adult spinal deformity (ASD), the HFRS has not been assessed in this population. The aim of this study was to utilize the HFRS to investigate the impact of frailty on outcomes in ASD patients undergoing posterior spinal fusion (PSF).

METHODS

A retrospective study was performed using the 2016-2019 National Inpatient Sample database. Adults with ASD undergoing elective PSF were identified using ICD-10-CM codes. Patients were categorized into HFRS-based frailty cohorts: Low (HFRS < 5) and Intermediate-High (HFRS ≥ 5). Patient demographics, comorbidities, intraoperative variables, and outcomes were assessed. Multivariate regression analyses were used to determine whether HFRS independently predicted extended length of stay (LOS), non-routine discharge, and increased cost.

RESULTS

Of the 7500 patients identified, 4000 (53.3%) were in the Low HFRS cohort and 3500 (46.7%) were in the Intermediate-High HFRS cohort. On average, age increased progressively with increasing HFRS scores (p < 0.001). The frail cohort experienced more postoperative adverse events (p < 0.001), greater LOS (p < 0.001), accrued greater admission costs (p < 0.001), and had a higher rate of non-routine discharge (p < 0.001). On multivariate analysis, Intermediate-High HFRS was independently associated with extended LOS (OR: 2.58, p < 0.001) and non-routine discharge (OR: 1.63, p < 0.001), though not increased admission cost (OR: 1.01, p = 0.929).

CONCLUSION

Our study identified HFRS to be significantly associated with prolonged hospitalizations and non-routine discharge. Other factors that were found to be associated with increased healthcare resource utilization include age, Hispanic race, West hospital region, large hospital size, and increasing number of AEs.

Impact of Affective Disorders on Inpatient Opioid Consumption and Hospital Outcomes Following Open Posterior Spinal Fusion for Adult Spine Deformity

OBJECTIVE

Affective disorders (ADs) are common and have a profound impact on surgical recovery, though few have studied the impact of ADs on inpatient narcotic consumption. The aim of this study was to assess the impact of ADs on inpatient narcotic consumption and healthcare resource utilization in patients undergoing spinal fusion for adult spinal deformity.

METHODS

A retrospective cohort study was performed using the 2016-2017 Premier Healthcare Database. Adults who underwent adult spinal deformity surgery were identified using International Classification of Disease, Tenth Revision, codes. Patients were grouped based on comorbid diagnosis of an AD. Demographics, comorbidities, intraoperative variables, complications, length of stay, admission costs, and nonroutine discharge rates were assessed. Increased inpatient opioid use was categorized by morphine milligram equivalents consumption greater than the 75th percentile. Multivariate regression analysis was used to identify predictors of increased healthcare recourse utilization.

RESULTS

Of the 1831 study patients, 674 (36.8%) had an AD. A smaller proportion of patients in the AD cohort were 65+ years of age (P = 0.001), while a greater proportion of patients in the AD cohort identified as non-Hispanic White (P < 0.001). A greater proportion of patients in the AD cohort had increased morphine milligram equivalents consumption (P < 0.001). The AD cohort also had a longer mean length of stay (P < 0.001). A greater proportion of patients in the AD cohort had nonroutine discharges (P = 0.039) and unplanned 30-day readmission (P = 0.041). On multivariate analysis, AD was significantly associated with increased cost (odds ratio: 1.61, P < 0.001) and nonroutine discharge (odds ratio: 1.36, P = 0.035).

CONCLUSIONS

ADs may be associated with increased inpatient opioid consumption and healthcare resource utilization.

Improvements in Outcomes and Cost After Adult Spinal Deformity Corrective Surgery Between 2008 and 2019

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

To assess whether patient outcomes and cost-effectiveness of adult spinal deformity (ASD) surgery have improved over the past decade.

BACKGROUND

Surgery for ASD is an effective intervention, but one that is also associated with large initial healthcare expenditures. Changes in the cost profile for ASD surgery over the last decade has not been evaluated previously.

MATERIALS AND METHODS

ASD patients who received surgery between 2008 and 2019 were included. Analysis of covariance was used to establish estimated marginal means for outcome measures [complication rates, reoperations, health-related quality of life, total cost, utility gained, quality adjusted life years (QALYs), cost-efficiency (cost per QALY)] by year of initial surgery. Cost was calculated using the PearlDiver database and represented national averages of Medicare reimbursement for services within a 30-day window including length of stay and death differentiated by complication/comorbidity, revision, and surgical approach. Internal cost data was based on individual patient diagnosis-related group codes, limiting revisions to those within two years (2Y) of the initial surgery. Cost per QALY over the course of 2008-2019 were then calculated.

RESULTS

There were 1236 patients included. There was an overall decrease in rates of any complication (0.78 vs . 0.61), any reoperation (0.25 vs . 0.10), and minor complication (0.54 vs . 0.37) between 2009 and 2018 (all P <0.05). National average 2Y cost decreased at an annual rate of $3194 ( R2 =0.6602), 2Y utility gained increased at an annual rate of 0.0041 ( R2 =0.57), 2Y QALYs gained increased annually by 0.008 ( R2 =0.57), and 2Y cost per QALY decreased per year by $39,953 ( R2 =0.6778).

CONCLUSION

Between 2008 and 2019, rates of complications have decreased concurrently with improvements in patient reported outcomes, resulting in improved cost effectiveness according to national Medicare average and individual patient cost data. The value of ASD surgery has improved substantially over the course of the last decade.

Preoperative characteristics are associated with increased likelihood of low early postoperative mobility after adult spinal deformity surgery

BACKGROUND CONTEXT

Low early postoperative mobility (LEPOM) has been shown to be associated with increased length of hospital stay, complication rates, and likelihood of nonhome discharge. However, few studies have examined preoperative characteristics associated with LEPOM in adult spinal deformity (ASD) patients.

PURPOSE

To investigate which preoperative patient characteristics may be associated with LEPOM after ASD surgery.

DESIGN

Retrospective review.

PATIENT SAMPLE

Included were 86 ASD patients with fusion of ≥5 levels for whom immediate-postoperative AM-PAC Basic Mobility Inpatient Short Form (6-Clicks) scores had been obtained.

OUTCOME MEASURES

The primary outcome of this study was the likelihood of LEPOM, defined as an AM-PAC score ≤15, which is associated with inability to stand for more than 1 minute.

METHODS

Significant cutoffs for preoperative characteristics associated with LEPOM were determined via threshold linear regression. Multivariable logistic regression was used to assess the impact of preoperative characteristics on the likelihood of LEPOM.

RESULTS

LEPOM was recorded in 38 patients (44.2%). Threshold regression identified the following cutoffs to be associated with LEPOM: preoperative Patient Reported Outcomes Measurement Information System (PROMIS) scores of ≥68 for Pain, <28.3 for Physical Function, and ≥63.4 for Anxiety; preoperative Oswestry disability index (ODI) score of ≥60; and body mass index (BMI) of ≥35.2. On multivariate analysis, preoperative PROMIS scores of ≥68 for Pain (odds ratio [OR] 5.3, confidence interval [CI] 1.2-22.8, p=.03), <28.3 for Physical Function (OR 10.1, CI 1.8-58.2, p=.01), and ≥63.4 for Anxiety (OR 4.7, CI 1.1-20.8, p=.04); preoperative ODI score ≥60 (OR 38.8, CI 4.0-373.6, p=.002); BMI ≥35.2 (OR 14.2, CI 1.3-160.0, p=.03), and male sex (OR 5.4, CI 1.2-23.7, p=.03) were associated with increased odds of LEPOM.

CONCLUSIONS

Preoperative PROMIS Pain, Physical Function, and Anxiety scores; ODI score; BMI; and male sex were associated with LEPOM. Several of these characteristics are modifiable risk factors and thus may be candidates for optimization before surgery.

LEVEL OF EVIDENCE

III.