Prolonged Length of Stay and Risk of Unplanned 30-Day Readmission After Elective Spine Surgery: Propensity Score-Matched Analysis of 33,840 Patients

Assessment of a Private Payer Bundled Payment Model for Lumbar Decompression Surgery

INTRODUCTION

Although bundled payment models are well-established in Medicare-aged individuals, private insurers are now developing bundled payment plans. The role of these plans in spine surgery has not been evaluated. Our objective was to analyze the performance of a private insurance bundled payment program for lumbar decompression and microdiskectomy.

METHODS

A retrospective review was conducted of all lumbar decompressions in a private payer bundled payment model at a single institution from October 2018 to December 2020. 120-day episode of care cost data were collected and reported as net profit or loss regarding set target prices. A stepwise multivariable linear regression model was developed to measure the effect of patient and surgical factors on net surplus or deficit.

RESULTS

Overall, 151 of 468 (32.2%) resulted in a deficit. Older patients (58.6 vs. 50.9 years, P < 0.001) with diabetes (25.2% vs. 13.9%, P = 0.004), hypertension (38.4% vs. 28.4%, P = 0.038), heart disease (13.9% vs. 7.57%, P = 0.030), and hyperlipidemia (51.7% vs. 35.6%, P = 0.001) were more likely to experience a loss. Surgically, decompression of more levels (1.91 vs. 1.19, P < 0.001), posterior lumbar decompression (86.8% vs. 56.5%, P < 0.001), and performing surgery at a tertiary hospital (84.8% vs. 70.3%, P < 0.001) were more likely to result in loss. All readmissions resulted in a loss (4.64% vs. 0.0%, P < 0.001). On multivariable regression, microdiskectomy (β: $2,398, P = 0.012) and surgery in a specialty hospital (β: $1,729, P = 0.096) or ambulatory surgery center (β: $3,534, P = 0.055) were associated with cost savings. Increasing number of levels, longer length of stay, active smoking, and history of cancer, dementia, or congestive heart failure were all associated with degree of deficit.

CONCLUSIONS

Preoperatively optimizing comorbidities and using risk stratification to identify those patients who may safely undergo surgery at a facility other than an inpatient hospital may help increase cost savings in a bundled payment model of working-age and Medicare-age individuals.

The ISSG-AO Complication Intervention Score, but Not Major/Minor Designation, is Correlated With Length of Stay Following Adult Spinal Deformity Surgery

STUDY DESIGN

Retrospective review.

OBJECTIVES

The International Spine Study Group-AO (ISSG-AO) Adult Spinal Deformity (ASD) Complication Classification System was developed to improve classification, reporting, and study of complications among patients undergoing ASD surgery. The ISSG-AO system classifies interventions to address complications by level of invasiveness: grade zero (none); grade 1, mild (e.g., medication change); grade 2, moderate (e.g., ICU admission); grade 3, severe (e.g., reoperation related to surgery of interest). To evaluate the efficacy of the ISSG-AO ASD Complication Classification System, we aimed to compare correlations between postoperative length of stay (LOS) and complication severity as classified by the ISSG-AO ASD and traditional major/minor complication classification systems.

METHODS

Patients age ≥18 in a multicenter ASD database who sustained in-hospital complications were identified. Complications were classified with the major/minor and ISSG-AO systems and correlated with LOS using an ensemble-based machine learning algorithm (conditional random forest) and a generalized linear mixed model.

RESULTS

490 patients at 19 sites were included. 64.9% of complications were major, and 35.1% were minor. By ISSG-AO classification, 20.4%, 66.1%, 6.7%, and 6.7% were grades 0-3, respectively. ISSG-AO complication grading demonstrated significant correlation with LOS, whereas major/minor complication classification demonstrated inverse correlation with LOS. In conditional random forest analysis, ISSG-AO classification had the greatest relative importance when assessing correlations across multiple variables with LOS.

CONCLUSIONS

The ISSG-AO system may help identify specific complications associated with prolonged LOS. Targeted interventions to avoid or reduce these complications may improve ASD surgical quality and resource utilization.

Predictive models to assess risk of extended length of stay in adults with spinal deformity and lumbar degenerative pathology: development and internal validation

BACKGROUND CONTEXT

Postoperative recovery after adult spinal deformity (ASD) operations is arduous, fraught with complications, and often requires extended hospital stays. A need exists for a method to rapidly predict patients at risk for extended length of stay (eLOS) in the preoperative setting.

PURPOSE

To develop a machine learning model to preoperatively estimate the likelihood of eLOS following elective multi-level lumbar/thoracolumbar spinal instrumented fusions (≥3 segments) for ASD.

STUDY DESIGN/SETTING

Retrospectively from a state-level inpatient database hosted by the Health care cost and Utilization Project.

PATIENT SAMPLE

Of 8,866 patients of age ≥50 with ASD undergoing elective lumbar or thoracolumbar multilevel instrumented fusions.

OUTCOME MEASURES

The primary outcome was eLOS (>7 days).

METHODS

Predictive variables consisted of demographics, comorbidities, and operative information. Significant variables from univariate and multivariate analyses were used to develop a logistic regression-based predictive model that use six predictors. Model accuracy was assessed through area under the curve (AUC), sensitivity, and specificity.

RESULTS

Of 8,866 patients met inclusion criteria. A saturated logistic model with all significant variables from multivariate analysis was developed (AUC=0.77), followed by generation of a simplified logistic model through stepwise logistic regression (AUC=0.76). Peak AUC was reached with inclusion of six selected predictors (combined anterior and posterior approach, surgery to both lumbar and thoracic regions, ≥8 level fusion, malnutrition, congestive heart failure, and academic institution). A cutoff of 0.18 for eLOS yielded a sensitivity of 77% and specificity of 68%.

CONCLUSIONS

This predictive model can facilitate identification of adults at risk for eLOS following elective multilevel lumbar/thoracolumbar spinal instrumented fusions for ASD. With a fair diagnostic accuracy, the predictive calculator will ideally enable clinicians to improve preoperative planning, guide patient expectations, enable optimization of modifiable risk factors, facilitate appropriate discharge planning, stratify financial risk, and accurately identify patients who may represent high-cost outliers. Future prospective studies that validate this risk assessment tool on external datasets would be valuable.

Association of inpatient opioid consumption on postoperative outcomes after open posterior spinal fusion for adult spine deformity

INTRODUCTION

Opioids are the most commonly used analgesic in the postoperative setting. However, few studies have analyzed the impact of high inpatient opioid use on outcomes following surgery, with no current studies assessing its effect on patients undergoing spinal fusion for an adult spinal deformity (ASD). Thus, the aim of this study was to investigate risk factors for high inpatient opioid use, as well as to determine the impact of high opioid use on outcomes such as adverse events (AEs), hospital length of stay (LOS), cost of hospital admission, discharge disposition, and readmission rates in patients undergoing spinal fusion for ASD.

METHODS

A retrospective cohort study was performed using the Premier healthcare database from the years 2016 and 2017. All adult patients > 40 years old who underwent thoracic or thoracolumbar fusion for ASD were identified using the ICD-10-CM diagnostic and procedural coding system. Patients were then categorized into three cohorts based on inpatient opioid use: Low MME (morphine milligram equivalents), Medium MME, and High MME. Patient demographics, comorbidities, treating hospital characteristics, intraoperative variables, postoperative AEs, LOS, discharge disposition, and total cost of hospital admission were assessed in the analysis. Multivariate regression analysis was done to determine independent predictors of high inpatient MME, prolonged LOS, and increased hospital cost.

RESULTS

Of 1673 patients included, 417 (24.9%) were classified as Low MME, 840 (50.2%) as Medium MME, and 416 (24.9%) as High MME. Age significantly decreased with increasing MME (Low: 71.0% 65 + years vs Medium: 62.0% 65 + years vs High: 47.4% 65 + years, p < 0.001), while the proportions of patients presenting with three or more comorbidities were similar across the cohorts (Low: 20.1% with 3 + comorbidities vs Medium: 18.0% with 3 + comorbidities vs High: 24.3% with 3 + comorbidities, p = 0.070). With respect to postoperative outcomes, the proportion of patients who experienced any AE (Low: 60.2% vs Medium: 68.8% vs High: 70.9%, p = 0.002), extended LOS (Low: 6.7% vs Medium: 20.7% vs High: 45.4%, p < 0.001), or non-routine discharge (Low: 66.6% vs Medium: 73.5% vs High: 80.1%, p = 0.003) each increased along with total MME. In addition, rates of 30-day readmission were greatest among the High MME cohort (Low: 8.4% vs Medium: 7.9% vs High: 12.5%, p = 0.022). On multivariate analysis, medium and high MME were associated with prolonged LOS [Medium: OR 4.41, CI (2.90, 6.97); High: OR 13.99, CI (8.99, 22.51), p < 0.001] and increased hospital cost [Medium: OR 1.69, CI (1.21, 2.39), p = 0.002; High: OR 1.66, CI (1.12, 2.46), p = 0.011]. Preadmission long-term opioid use [OR 1.71, CI (1.07, 2.7), p = 0.022], a prior opioid-related disorder [OR 11.32, CI (5.92, 23.49), p < 0.001], and chronic pulmonary disease [OR 1.39, CI (1.06, 1.82), p = 0.018] were each associated with a high inpatient MME on multivariate analysis.

CONCLUSION

Our study demonstrated that increasing inpatient MME consumption was associated with extended LOS and increased hospital cost in patients undergoing spinal fusion for ASD. Further studies identifying risk factors for increased MME consumption may provide better risk stratification for postoperative opioid use and healthcare resource utilization.

Factors contributing to a longer length of stay in adults admitted to a quaternary spinal care center

BACKGROUND

Longer hospital length of stay (LOS) has been associated with worse outcomes and increased resource utilization. However, diagnostic and patient-level factors associated with LOS have not been well studied on a large scale. The goal was to identify patient, surgical and organizational factors associated with longer patient LOS for adult patients at a high-volume quaternary spinal care center.

METHODS

We performed a retrospective analysis of 13,493 admissions from January 2006 to December 2019. Factors analyzed included age, sex, admission status (emergent vs scheduled), ASIA grade, operative vs non-operative management, mean blood loss, operative time, and adverse events. Specific adverse events included surgical site infection (SSI), other infection (systemic or UTI), neuropathic pain, delirium, dural tear, pneumonia, and dysphagia. Diagnostic categories included trauma, oncology, deformity, degenerative, and "other". A multivariable linear regression model was fit to log-transformed LOS to determine independent factors associated with patient LOS, with effects expressed as multipliers on mean LOS.

RESULTS

Mean LOS for the population (SD) was 15.8 (34.0) days. Factors significantly (p < 0.05) associated with longer LOS were advanced patient age [multiplier on mean LOS 1.011/year (95% CI: 1.007-1.015)], emergency admission [multiplier on mean LOS 1.615 (95% CI: 1.337-1.951)], ASIA grade [multiplier on mean LOS 1.125/grade (95% CI: 1.051-1.205)], operative management [multiplier on mean LOS 1.211 (95% CI: 1.006-1.459)], and the occurrence of one or more AEs [multiplier on mean LOS 2.613 (95% CI: 2.188-3.121)]. Significant AEs included postoperative SSI [multiplier on mean LOS 1.749 (95% CI: 1.250-2.449)], other infections (systemic infections and UTI combined) [multiplier on mean LOS 1.650 (95% CI: 1.359-2.004)], delirium [multiplier on mean LOS 1.404 (95% CI: 1.103-1.787)], and pneumonia [multiplier on mean LOS 1.883 (95% CI: 1.447-2.451)]. Among the diagnostic categories explored, degenerative patients experienced significantly shorter LOS [multiplier on mean LOS 0.672 (95%CI: 0.535-0.844), p < 0.001] compared to non-degenerative categories.

CONCLUSION

This large-scale study taking into account diagnostic categories identified several factors associated with patient LOS. Future interventions should target modifiable factors to minimize LOS and guide hospital resource allocation thereby improving patient outcomes and quality of care and decreasing healthcare-associated costs.

Thirty-day unplanned reoperations of thoracic spine surgery: 10 years of data from a single center with 3,242 patients

BACKGROUND CONTEXT

Unplanned reoperation is a useful quality indicator for spine surgery. However, the rates of a 30-day unplanned reoperation in patients undergoing thoracic spinal surgery are not well established.

PURPOSE

To assess the rates, reasons, and risk factors of 30-day unplanned reoperations for thoracic spine surgeries in a single center study.

STUDY DESIGN

A retrospective observational study.

PATIENT SAMPLE

3,242 patients who underwent thoracic spinal surgery at our institution in the past decade were included.

OUTCOME MEASURES

The incidence, chief reasons, and risk factors for unplanned reoperations within 30 days after thoracic spinal surgery.

METHODS

We retrospectively analyzed the data of all patients who underwent thoracic spinal surgery between January 2012 and December 2021. Statistical methods, including univariate and multivariate analyses, were performed to assess the incidence, reasons, and risk factors for thoracic degenerative diseases, spinal tumors, kyphosis deformity, and spinal trauma.

RESULTS

Of the 3,242 patients who underwent thoracic spinal surgery, 107 (3.30%) required unplanned reoperations within 30 days due to epidural hematoma (1.17%), wound complications (0.80%), implant complications (0.43%), inadequate decompression (0.25%), and other causes (0.65%). Patients with degenerative disease (3.88%), spinal tumor (2.98%), and kyphosis deformity (3.33%) had significantly higher incidences of reoperation than those with spinal trauma (1.47%). Unplanned reoperations were classified as hyperacute (30.84%), acute (31.76%), and subacute (37.38%). After univariate analysis, several factors were associated with unplanned reoperation in the 4 cohorts of thoracic spine diseases (p<.05). Multivariate logistic regression analysis revealed that upper thoracic spine surgery (p=.001), concomitant dekyphosis (p=.027), and longer activated partial thromboplastin time (p=.025) were risk factors of unplanned reoperation for thoracic degenerative disease. Whereas American Society of Anesthesiologists (ASA) grade III (p=.015), combined approach (p=.016), and operation time longer than 420 min (p=.042) for spinal tumor, and similar ankylosing spondylitis (p=.023) and operation time longer than 340 min (p=.041) were risk factors of unplanned reoperation for kyphosis deformity.

CONCLUSIONS

The unplanned reoperation rate for thoracic spine surgery was 3.30%, with epidural hematoma and wound complications being the most common reasons. However, upper thoracic spine surgery, concomitant dekyphosis, underlying coagulation disorder, longer operation time, higher ASA grade, and comorbidities of ankylosing spondylitis led to an increased risk of unplanned reoperation within 30 days of thoracic spine surgery.

Incidences, causes and risk factors of unplanned reoperations within 30 days of spine surgery: a single-center study based on 35,246 patients

BACKGROUND CONTEXT

Unplanned reoperation, a quality indicator in spine surgery, has not been sufficiently investigated in a large-scale, single-center study.

PURPOSE

To assess the incidences, causes, and risk factors of unplanned reoperations within 30 days of spine surgeries in a single-center study.

STUDY DESIGN

Retrospective observational study.

PATIENT SAMPLE

A cohort of 35,246 patients who underwent spinal surgery in our hospital were included.

OUTCOME MEASURES

The rates, chief reasons, and risk factors for unplanned reoperations within 30 days of spine surgery.

METHODS

We retrospectively analyzed the data for patients who underwent spine surgeries for degenerative spinal disorders, tumor, or deformity and had subsequent unplanned operations within 30 days at a single tertiary academic hospital from January 2016 to July 2021. Univariate and multivariate analyses were performed to assess the incidences, causes, and risk factors.

RESULTS

Out of 35,246 spinal surgery patients, 297 (0.84%) required unplanned reoperations within 30 days of spine surgery. Patients with a thoracic degenerative disease (3.23%), spinal tumor (1.63%), and spinal deformity (1.50%) had significantly higher rates of reoperation than those with atlantoaxial (0.61%), cervical (0.65%), and lumbar (0.82%) degenerative disease. The common causes for reoperation included epidural hematoma (0.403%), wound infections (0.148%), neurological deficit (0.108%), and pedicle screw malposition (0.077%). Unplanned reoperations were classified as hyperacute (45.45%), acute (30.98%), subacute (15.82%), or chronic (7.74%). Univariate analysis indicated that 20 clinical factors were associated with unplanned reoperation (p<.05). Multivariate Poisson regression analysis revealed that anemia (p<.001), osteoporosis (p=.048), ankylosing spondylitis (p=.008), preoperative foot drop (p=.011), deep venous thrombosis (p<.001), and previous surgical history (p<.001) were independent risk factors for unplanned spinal reoperation.

CONCLUSIONS

The incidence of unplanned spinal reoperations was 0.84%. The chief common causes were epidural hematoma, wound infections, neurological deficit, and pedicle screw malposition. Anemia, osteoporosis, ankylosing spondylitis, preoperative foot drop, deep venous thrombosis, and previous surgical history led to an increased risk of unplanned reoperation within 30 days of spine surgery.

Variations in LOS and its main determinants overtime at an academic spinal care center from 2006-2019

Objectives

Efforts to safely reduce hospital LOS while maintaining quality outcomes and patient satisfaction are paramount. The primary goal of this study was to assess trends in LOS at a high-volume quaternary care spine center. Secondary goals were to assess trends in factors most associated with prolonged LOS.

Methods

This is a prospective study of all consecutive patients admitted from January 2006 to December 2019. Data included demographics, diagnostic category (degenerative, oncology, deformity, trauma, other), LOS (mean, median, interquartile range, standard deviation, defined as days from admission to discharge), and in-hospital adverse events.

Results

A total of 13,493 patients were included. Overall LOS has not changed over time with an overall median of 6.3 days (p = 0.451). Median LOS significantly increased for patients treated for degenerative pathology from 2.2 days in 2006 to 3.2 days in 2019 (p = 0.019). LOS has not changed for patients treated for deformity (overall median 6.8 days, p = 0.411), oncology (overall median 11.0 days, p = 0.051), or trauma (overall median 11.8 days, p = 0.582). Emergency admissions increased 3.2%/year for degenerative pathologies (p =  < 0.001). Mean age has increased from 48.4 years in 2006 to 58.1 years in 2019 (p =  < 0.001). This trend was observed in the deformity, degenerative and trauma group, not for patients treated for oncological disease. More adverse events were significantly associated with increasing age.

Conclusion

This is the first North American study to comprehensively analyze trends in LOS for spinal surgery overtime in an academic center. Overall, LOS has not changed from 2006–2019. Various factors that influence LOS appear to have balanced each other. It may also be explained by the changing epidemiology of both elective and emergency surgeries. These findings provide opportunities for intervention and improvement, targeted at the geriatric population, to reduce length of hospitalization.