Distribution and Determinants of 90-Day Payments for Multilevel Posterior Lumbar Fusion: A Medicare Analysis

Social determinants of health and disparities in spine surgery: a 10-year analysis of 8,565 cases using ensemble machine learning and multilayer perceptron

BACKGROUND CONTEXT

The influence of SDOH on spine surgery is poorly understood. Historically, researchers commonly focused on the isolated influences of race, insurance status, or income on healthcare outcomes. However, analysis of SDOH is becoming increasingly more nuanced as viewing social factors in aggregate rather than individually may offer more precise estimates of the impact of SDOH on healthcare delivery.

PURPOSE

The aim of this study was to evaluate the effects of patient social history on length of stay (LOS) and readmission within 90 days following spine surgery using ensemble machine learning and multilayer perceptron.

STUDY DESIGN

Retrospective chart review.

PATIENT SAMPLE

8,565 elective and emergency spine surgery cases performed from 2013 to 2023 using our institution's database of longitudinally collected electronic medical record information.

OUTCOMES MEASURES

Patient LOS, discharge disposition, and rate of 90-day readmission.

METHODS

Ensemble machine learning and multilayer perceptron were employed to predict LOS and readmission within 90 days following spine surgery. All other subsequent statistical analysis was performed using SPSS version 28. To further assess correlations among variables, Pearson's correlation tests and multivariate linear regression models were constructed. Independent sample t-tests, paired sample t-tests, one-way analysis of variance (ANOVA) with post-hoc Bonferroni and Tukey corrections, and Pearson's chi-squared test were applied where appropriate for analysis of continuous and categorical variables.

RESULTS

Black patients demonstrated a greater LOS compared to white patients, but race and ethnicity were not significantly associated with 90-day readmission rates. Insured patients had a shorter LOS and lower readmission rates compared to non-insured patients, as did privately insured patients compared to publicly insured patients. Patients discharged home had lower LOS and lower readmission rates, compared to patients discharged to other facilities. Marriage decreased both LOS and readmission rates, underweight patients showcased increased LOS and readmission rates, and religion was shown to impact LOS and readmission rates. When utilizing patient social history, lab values, and medical history, machine learning determined the top 5 most-important variables for prediction of LOS -along with their respective feature importances-to be insurance status (0.166), religion (0.100), ICU status (0.093), antibiotic use (0.061), and case status: elective or urgent (0.055). The top 5 most-important variables for prediction of 90-day readmission-along with their respective feature importances-were insurance status (0.177), religion (0.123), discharge location (0.096), emergency case status (0.064), and history of diabetes (0.041).

CONCLUSIONS

This study highlights that SDOH is influential in determining patient length of stay, discharge disposition, and likelihood of readmission following spine surgery. Machine learning was utilized to accurately predict LOS and 90-day readmission with patient medical history, lab values, and social history, as well as social history alone.

Biomechanical Comparison of Corticopedicular Spine Fixation versus Pedicle Screw Fixation in a Lumbar Degenerative Spondylolisthesis Finite Element Analysis Model

OBJECTIVE

To compare the stability of a corticopedicular posterior fixation (CPPF) device with traditional pedicle screws for decompression and fusion in adult degenerative lumbar spondylolisthesis.

METHODS

Finite element analysis (FEA) was used in a validated model of grade 1 L4-L5 spondylolisthesis to compare segmental stability after laminectomy alone, laminectomy with pedicle screw fixation, or laminectomy with CPPF device fixation. A 500-N follower load was applied to the model and different functional movements were simulated by applying a 7.5-Nm force in different directions. Outcomes included degrees of motion, tensile forces experienced in the CPPF device, and stresses in surrounding cortical bone.

RESULTS

At maximum loading, laminectomy alone demonstrated a 1° increase in flexion range of motion, from 6.35° to 7.39°. Laminectomy with pedicle screw fixation and CPPF device fixation both reduced spinal segmental motion to ≤1° at maximum loading in all ranges of motion, including flexion (0.94° and 1.09°), extension (-0.85° and -1.08°), lateral bending (-0.56° and -0.96°), and torsion (0.63° and 0.91°), respectively. There was no significant difference in segmental stability between pedicle screw fixation and CPPF device fixation during maximum loading, with a difference of ≤0.4° in any range of motion. Tensile forces in the CPPF device remained ≤51% the ultimate load to failure (487 N) and stress in surrounding cortical bone remained ≤84% the ultimate stress of cortical bone (125.4 MPa) during maximum loading.

CONCLUSIONS

CPFF fixation demonstrated similar segmental stability to traditional pedicle screw fixation whereas tensile forces and stress in surrounding cortical bone remained below the load to failure.

Does Surgical Day of Week Affect Patient Outcomes and Hospital Costs Following Lumbar Fusion?

Background As the population ages, surgical intervention for degenerative spine conditions is increasing, and this causes a commiserate increase in healthcare expenditures associated with these procedures. Little research has been done on the effect of early-week versus later-week surgeries on patient outcomes, cost, and length of stay (LOS) in patients undergoing lumbar fusion surgery. The purpose of this study is to compare LOS, patient outcomes, and hospital costs between patients having surgery early in the week and later in the week. Methods A retrospective review of 771 patients undergoing a one-, two-, or three-level lumbar fusion from December 2020 to December 2023 at a single institution was performed. Demographics, surgical details, postoperative outcomes and cost were compared between patients who had surgery on Monday, Tuesday, and Wednesday, to those having surgery Thursday or Friday. Univariate and multivariate analyses were performed to compare the groups. Results There were no differences in age, sex, BMI, race, American Society of Anesthesiology (ASA) scores, Charlson Comorbidity Index (CCI) scores, number of operative levels or inpatient/outpatient status between early- and late-week surgeries. Postoperatively the only significant difference was cost, late-week surgeries were, on average, $3,697 more expensive than early-week surgeries ($26,506 vs. $22,809; p<0.001). On multivariate analysis late-week surgeries were 2.47 times more likely to have a non-home discharge (OR: 2.47, 95% CI: 1.24 to 4.95; p=0.010) and 2.19 times more likely to have a 30-day readmission (OR: 2.19, 95% CI:1.01 to 4.74; p=0.044) Additionally, late-week surgeries were $2,041.55 (β:2,041.55, 95% CI: 804.72 to 3,278.38; p=0.001) more expensive than early-week surgeries. Conclusions At our institution, patients undergoing one- to three-level lumbar fusion surgery on Thursday or Friday had a higher risk of non-home discharge, 30-day readmission, and incurred higher cost than those having early-week surgery. Further research is needed to elucidate the reasons for these findings and to evaluate interventions aimed at improving outcomes for patients undergoing surgery later in the week.

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.

Readmission and Resource Utilization in Patients From Socioeconomically Distressed Communities Following Lumbar Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To determine whether: (1) patients from communities of socioeconomic distress have higher readmission rates or postoperative healthcare resource utilization and (2) there are differences in patient-reported outcome measures (PROMs) based on socioeconomic distress.

SUMMARY OF BACKGROUND DATA

Socioeconomic disparities affect health outcomes, but little evidence exists demonstrating the impact of socioeconomic distress on postoperative resource utilization or PROMs.

METHODS

A retrospective review was performed on patients who underwent lumbar fusion at a single tertiary academic center from January 1, 2011 to June 30, 2021. Patients were classified according to the distressed communities index. Hospital readmission, postoperative prescriptions, patient telephone calls, follow-up office visits, and PROMs were recorded. Multivariate analysis with logistic, negative binomial regression or Poisson regression were used to investigate the effects of distressed communities index on postoperative resource utilization. Alpha was set at P <0.05.

RESULTS

A total of 4472 patients were included for analysis. Readmission risk was higher in distressed communities (odds ratio, 1.75; 95% confidence interval, 1.06-2.87; P =0.028). Patients from distressed communities (odds ratio, 3.94; 95% confidence interval, 1.60-9.72; P =0.003) were also more likely to be readmitted for medical, but not surgical causes ( P =0.514), and distressed patients had worse preoperative (visual analog-scale Back, P <0.001) and postoperative (Oswestry disability index, P =0.048; visual analog-scale Leg, P =0.013) PROMs, while maintaining similar magnitudes of clinical improvement. Patients from distressed communities were more likely to be discharged to a nursing facility and inpatient rehabilitation unit (25.5%, P =0.032). The race was not independently associated with readmissions ( P =0.228).

CONCLUSION

Socioeconomic distress is associated with increased postoperative health resource utilization. Patients from distressed communities have worse preoperative PROMs, but the overall magnitude of improvement is similar across all classes.

LEVEL OF EVIDENCE

Level IV.

Risk Factors of Unplanned Readmission after Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-Analysis

PURPOSE

With an increasing number of anterior cervical discectomy and fusion (ACDF) being conducted for degenerative cervical disc disease, there is a rising interest in the related quality of management and healthcare costs. Unplanned readmission after ACDF affects both the quality of management and medical expenses. This meta-analysis was performed to evaluate the risk factors of unplanned readmission after ACDF to improve the quality of management and prevent increase in healthcare costs.

MATERIALS AND METHODS

We searched the databases of PubMed, EMBASE, Web of Science, and Cochrane Library to identify eligible studies using the searching terms, "readmission" and "ACDF." A total of 10 studies were included.

RESULTS

Among the demographic risk factors, older age [weighted mean difference (WMD), 3.93; 95% confidence interval (CI), 2.30-5.56; p<0.001], male [odds ratio (OR), 1.23; 95% CI, 1.10-1.36; p<0.001], and private insurance (OR, 0.34; 95% CI, 0.17-0.69; p<0.001) were significantly associated with unplanned readmission. Among patient characteristics, hypertension (HTN) (OR, 2.14; 95% CI, 1.41-3.25; p<0.001), diabetes mellitus (DM) (OR, 1.59; 95% CI, 1.20-2.11; p=0.001), coronary artery disease (CAD) (OR, 2.87; 95% CI, 2.13-3.86; p<0.001), American Society of Anesthesiologists (ASA) physical status grade >2 (OR, 2.13; 95% CI, 1.68-2.72; p<0.001), and anxiety and depression (OR, 1.39; 95% CI, 1.29-1.51; p<0.001) were significantly associated with unplanned readmission. Among the perioperative factors, pulmonary complications (OR, 22.52; 95% CI, 7.21-70.41; p<0.001) was significantly associated with unplanned readmission.

CONCLUSION

Male, older age, HTN, DM, CAD, ASA grade >2, anxiety and depression, pulmonary complications were significantly associated with an increased occurrence of unplanned readmission after ACDF.

Is Discretionary Care Associated with Safety Among Medicare Beneficiaries Undergoing Spine Surgery?

BACKGROUND

Spine surgery and its corresponding costs have increased in recent years and are variable across geographic regions. Discretionary care is the component of spending variation that is independent of illness severity, age, and regional pricing. It is unknown whether greater discretionary care is associated with improved safety for patients undergoing spine surgery, as we would expect from value-based health care.

METHODS

We conducted an analysis of 5 spine surgery cohorts based on Medicare claims from 2013 to 2017. Patients were grouped into quintiles based on the Dartmouth Atlas End-of-Life Inpatient Care Index (EOL), reflecting regional spending variation attributed to discretionary care. Multivariable regression examined the association between discretionary care and safety measures while controlling for age, sex, race, comorbidity, and hospital features.

RESULTS

We observed a threefold to fourfold variation in 90-day episode-of-care cost across regions, depending on the cohort. Spine-specific spending was correlated with EOL quintile, confirming that spending variation is due more to discretionary care than it is to pricing, age, or illness severity. Greater spending across EOL quintiles was not associated with improved safety, and, in fact, was associated with poorer safety in some cohorts. For example, all-cause readmission was greater in the high-spending EOL quintile relative to the low-spending EOL quintile among the "fusion, except cervical" cohort (14.2% vs. 13.1%; OR = 1.10; 95% CI = 1.05 to 1.20), the "complex fusion" cohort (28.0% vs. 25.4%; OR = 1.15; 95% CI = 1.01 to 1.30), and the "cervical fusion" cohort (15.0% vs. 13.6%; OR = 1.12; 95% CI = 1.05 to 1.20).

CONCLUSIONS

Wide variation in spending was not explained by differences in illness severity, age, or pricing, and increased discretionary care did not enhance safety. These findings point to inefficient use of health-care resources, a potential focus of reform.

LEVEL OF EVIDENCE

Economic and Decision Analysis Level IV. See Instructions for Authors for a complete description of levels of evidence.

Outpatient Versus Inpatient Surgical Fixation of Isolated Ankle Fractures: An Analysis of 90-Day Complications, Readmissions, and Costs

Despite increasing interest toward managing isolated ankle fractures in an outpatient setting, evidence of its safety remains largely limited. The 2007 to 2014 Humana Administrative Claims database was queried to identify patients undergoing open reduction internal fixation for unimalleolar, bimalleolar, or trimalleolar isolated closed ankle fractures. Two cohorts (outpatient versus inpatient) were then matched on the basis of age, sex, race, region, fracture type (uni-/bi-/trimalleolar) and Elixhauser Comorbidity Index to control for selection bias. Multivariate regression analyses were performed to report independent impact of outpatient-treated ankle fracture surgery on 90-day complications, readmission, and emergency department visit rates. Independent-samples t test was used to compare global 90-day costs between cohorts. A total of 5317 inpatient-treated and 6941 outpatient-treated closed ankle fractures were included in the final cohort. After matching and multivariate analyses, patients with outpatient ankle fractures, compared with patients with inpatient ankle fractures, had statistically lower rates of pneumonia (2.3% versus 4.0%; p < .001), myocardial infarction (0.9% versus 1.8%; p = .005), acute renal failure (2.2% versus 5.3%; p < .001), urinary tract infections (7.4% versus 12.3%; p < .001), and pressure ulcers (0.9% versus 2.0%; p = .001). Outpatient ankle fractures also had lower rates of 90-day readmissions (9.7% versus 14.1%; p < .001) and emergency department visits (13.8% versus 16.2%; p = .028). Last, overall 90-day costs for outpatient ankle fractures were nearly $9000 lower than costs for inpatient ankle fractures ($12,923 versus $21,866; p < .001). Based on our findings, it appears that outpatient treatment of ankle fractures can be deemed safe and feasible in a select cohort of patients.

Degenerative Adult Cervical Kyphosis With Secondary Diagnosis Codes Are Associated With Higher Cost and Complications After Spinal Fusion: A Medicare Database Study

BACKGROUND

Adult cervical deformity (ACD) is a potentially debilitating condition resulting from kyphosis, scoliosis, or both, of the cervical spine. Conditions such as ankylosing spondylitis, rheumatoid arthritis, Parkinson's disease, and neuromuscular diseases are particularly known to cause severe deformities. We describe the 90-day cost and complications associated with spinal fusion for ACD using International Classification of Diseases (ICD) coding terminology and study if secondary diagnoses associated with potential for severe deformity affect the cost and complication profile of ACD surgery.

METHODS

Medicare data were used to study hospital costs and complications within 90 days after primary cervical fusion for ACD in 2 cohorts matched by demographics and comorbidity burden: (1) patients with diagnoses of secondary pathology (SP) known to cause severe deformity and (2) without SP. Univariate and multiple-variable analyses to study incidence of complications, readmission, and costs within 90 days were done.

RESULTS

A total of 2900 patients in matched cohorts of 1450 each were included. The mean index hospital payment ($26 545 ± $25 968 versus $22 991 ± $21 599) and length of stay (4.8 ± 5.6 versus 3.9 ± 4.5 days) was significantly (P < .01) higher in ACD patients with SP. On adjusted analysis, the risk of procedure-related complications was higher (odds ratio [OR] = 1.47, 95% confidence interval [CI], 1.18-1.83) in patients with SP than those without SP, but not readmission (OR = 1.04, 95% CI, 0.82-1.32) or refusion (OR = 0.95, 95% CI, 0.45-2.0) within 90 days. The cost profile of complications, readmission, and refusion has been given.

CONCLUSIONS

ACD patients with secondary diagnosis codes such as inflammatory arthropathy or neuromuscular pathology incur higher 90-day costs due to the inherent requirement of bigger fusions and higher risk of peri-operative complications, but with similar risk of readmission and refusion as those without SP.

LEVEL OF EVIDENCE

3.

CLINICAL RELEVANCE

With evolving health care reforms and payment models, knowledge of conditions associated with higher expenditure after elective spine surgical procedures will be beneficial to providers and payors for appropriate risk stratification.

Fellow Versus Resident: Graduate Medical Education and Patient Outcomes After Anterior Cervical Diskectomy and Fusion Surgery

INTRODUCTION

The effect of spine fellow versus orthopaedic surgery resident assistance on outcomes in anterior cervical diskectomy and fusion (ACDF) has not been well studied. The objective of this study was to determine differences in patient health-related outcomes based on the level of surgical trainees.

METHODS

Consecutive cases of ACDF (n = 407) were reviewed at a single high-volume institution between 2015 and 2017 and were separated into two groups based on whether they were fellow-assisted or resident-assisted. Demographic and clinical variables were recorded, and health-related quality of life was evaluated using the Short Form-12 (SF-12) survey. The SF-12, visual analog scale pain score, and neck disability index were compared between the two groups. Surgery level, surgical time, preoperative Charlson Comorbidity Index, estimated blood loss, equivalent morphine use, perioperative complications, and 30-day readmission were also recorded. Patient outcomes were compared using an unpaired t-test as well as multivariate linear regression, controlling for age, sex, body mass index, Charlson Comorbidity Index, presurgical visual analog scale, SF-12, and neck disability index. Results were reported with the 95% confidence interval.

RESULTS

Spine surgery fellows and orthopaedic surgery residents participated in 228 and 179 ACDF cases, respectively. No notable demographic differences between the two groups were found. A higher proportion of three or more level ACDF surgeries assisted by fellows versus residents was found. Estimated blood loss was greater in fellow-assisted ACDF cases. Both surgery time and total time in the room were also longer in the fellow-assisted ACDF group. No 30-day readmissions were found in either groups, and only one case of acute hemorrhagic anemia was found in the fellow-assisted group. Overall, postoperative complications were higher in the resident group; however, no difference with regard to intraoperative complications between groups was found.

DISCUSSION

This study shows that patient health-related outcomes are similar in ACDF cases that were fellow-assisted versus resident-assisted. However, fellow-assisted ACDF cases were associated with more blood loss and longer surgery time.

Utilization of Predictive Modeling to Determine Episode of Care Costs and to Accurately Identify Catastrophic Cost Nonwarranty Outlier Patients in Adult Spinal Deformity Surgery: A Step Toward Bundled Payments and Risk Sharing

STUDY DESIGN

Retrospective review of prospectively-collected, multicenter adult spinal deformity (ASD) database.

OBJECTIVE

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.

SUMMARY OF BACKGROUND DATA

Cost outliers or surgeries resulting in CC are a major concern for ASD surgery as some question the sustainability of these surgical treatments.

METHODS

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).

RESULTS

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.

CONCLUSION

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.

LEVEL OF EVIDENCE

3.

Epidemiology and Socioeconomic Trends in Adult Spinal Deformity Care

Adult spinal deformity (ASD) has gained significant attention over the past decade with improvements in diagnostic tools, classification schemes, and surgical technique. The demographics of the aging population in the United States are undergoing a fundamental shift as medical care advances and life expectancy increases. The “baby boomers” represent the fastest growing demographic in the United States and by 2050, the number of individuals 65 yr and older is projected to reach 89 million, more than double its current size. Based on current prevalence estimates there are approximately 27.5 million elderly individuals with some form of spinal deformity, which will place a significant burden on our health care systems. Rates of surgery for ASD and case complexity are both increasing, with concomitant increase in the cost of deformity care. At the same time, patients are more medically complex with increasing number of comorbidities that result in increased surgical risk and complication profiles. This review aims to highlight recent trends in the epidemiology and socioeconomic patterns in surgery for ASD.

30- and 90-Day Unplanned Readmission Rates, Causes, and Risk Factors After Cervical Fusion: A Single-Institution Analysis

STUDY DESIGN

Retrospective cohort study OBJECTIVE.: To study 30- and 90-day readmission rates, causes, and risk factors after anterior cervical discectomy and fusion (ACDF) and posterior cervical fusion (PCF).

SUMMARY OF BACKGROUND DATA

Existing data on readmission after cervical fusion is majorly derived from national databases. Given their inherent limitations in accuracy, follow-up available, and missing data, we intend to add to literature from our institutional analysis.

METHODS

Patients who underwent ACDF and PCF for degenerative cervical pathology in 2013 and 2014 were identified for the study. Comprehensive chart review was performed to record demographics and clinical patient profile. Hospital readmission within 30 and 90 days was identified, and the causes and management were recorded. Binary logistic regression analysis was done to study risk factors for readmission. ACDF and PCF were studied separately.

RESULTS

Our analysis included a total of 549 patients, stratified as 389 ACDFs and 160 PCFs. The 30- and 90-day unplanned readmission rate was 5.1% and 7.7% after ACDF. These rates were 11.2% and 16.9% after PCF. The most common cause of readmission was systemic infection and sepsis after ACDF and PCF (31.4% and 25.8% of readmitted, respectively), followed by pulmonary complications after ACDF (14.3% of readmitted) and wound complications after PCF (19.4% of readmitted). Predictors of readmission after ACDF included heart failure, history of malignancy, history of deep vein thrombosis/pulmonary embolism, and any intraoperative complication. In the PCF cohort, history of ischemic heart disease, increasing number of fusion levels and longer length of stay were independently predictive.

CONCLUSION

The rates, causes, and risk factors of readmission after ACDF and PCF have been identified. There is variation in published data regarding the incidence and risk factors for readmission after cervical fusion; however, majority of readmissions occur due to medical complications and systemic infection.

LEVEL OF EVIDENCE

3.

Adverse events and their risk factors 90 days after cervical spine surgery: analysis from the Michigan Spine Surgery Improvement Collaborative

OBJECTIVE

The Michigan Spine Surgery Improvement Collaborative (MSSIC) is a statewide, multicenter quality improvement initiative. Using MSSIC data, the authors sought to identify 90-day adverse events and their associated risk factors (RFs) after cervical spine surgery.

METHODS

A total of 8236 cervical spine surgery cases were analyzed. Multivariable generalized estimating equation regression models were constructed to identify RFs for adverse events; variables tested included age, sex, diabetes mellitus, disc herniation, foraminal stenosis, central stenosis, American Society of Anesthesiologists Physical Classification System (ASA) class > II, myelopathy, private insurance, anterior versus posterior approach, revision procedures, number of surgical levels, length of procedure, blood loss, preoperative ambulation, ambulation day of surgery, length of hospital stay, and discharge disposition.

RESULTS

Ninety days after cervical spine surgery, adverse events identified included radicular findings (11.6%), readmission (7.7%), dysphagia requiring dietary modification (feeding tube or nothing by mouth [NPO]) (6.4%), urinary retention (4.7%), urinary tract infection (2.2%), surgical site hematoma (1.1%), surgical site infection (0.9%), deep vein thrombosis (0.7%), pulmonary embolism (0.5%), neurogenic bowel/bladder (0.4%), myelopathy (0.4%), myocardial infarction (0.4%), wound dehiscence (0.2%), claudication (0.2%), and ileus (0.2%). RFs for dysphagia included anterior approach (p < 0.001), fusion procedures (p = 0.030), multiple-level surgery when considering anterior procedures only (p = 0.037), and surgery duration (p = 0.002). RFs for readmission included ASA class > II (p < 0.001), while preoperative ambulation (p = 0.001) and private insurance (p < 0.001) were protective. RFs for urinary retention included increasing age (p < 0.001) and male sex (p < 0.001), while anterior-approach surgery (p < 0.001), preoperative ambulation (p = 0.001), and ambulation day of surgery (p = 0.001) were protective. Preoperative ambulation (p = 0.010) and anterior approach (p = 0.002) were protective of radicular findings.

CONCLUSIONS

A multivariate analysis from a large, multicenter, prospective database identified the common adverse events after cervical spine surgery, along with their associated RFs. This information can lead to more informed surgeons and patients. The authors found that early mobilization after cervical spine surgery has the potential to significantly decrease adverse events.