National trends in outpatient surgical treatment of degenerative cervical spine disease

Predicting conversion of ambulatory ACDF patients to inpatient: a machine learning approach

BACKGROUND CONTEXT

Machine learning is a powerful tool that has become increasingly important in the orthopedic field. Recently, several studies have reported that predictive models could provide new insights into patient risk factors and outcomes. Anterior cervical discectomy and fusion (ACDF) is a common operation that is performed as an outpatient procedure. However, some patients are required to convert to inpatient status and prolonged hospitalization due to their condition. Appropriate patient selection and identification of risk factors for conversion could provide benefits to patients and the use of medical resources.

PURPOSE

This study aimed to develop a machine-learning algorithm to identify risk factors associated with unplanned conversion from outpatient to inpatient status for ACDF patients.

STUDY DESIGN/SETTING

This is a machine-learning-based analysis using retrospectively collected data.

PATIENT SAMPLE

Patients who underwent one- or two-level ACDF in an ambulatory setting at a single specialized orthopedic hospital between February 2016 to December 2021.

OUTCOME MEASURES

Length of stay, conversion rates from ambulatory setting to inpatient.

METHODS

Patients were divided into two groups based on length of stay: (1) Ambulatory (discharge within 24 hours) or Extended Stay (greater than 24 hours but fewer than 48 hours), and (2) Inpatient (greater than 48 hours). Factors included in the model were based on literature review and clinical expertise. Patient demographics, comorbidities, and intraoperative factors, such as surgery duration and time, were included. We compared the performance of different machine learning algorithms: Logistic Regression, Random Forest (RF), Support Vector Machine (SVM), and Extreme Gradient Boosting (XGBoost). We split the patient data into a training and validation dataset using a 70/30 split. The different models were trained in the training dataset using cross-validation. The performance was then tested in the unseen validation set. This step is important to detect overfitting. The performance was evaluated using the area under the curve (AUC) of the receiver operating characteristics analysis (ROC) as the primary outcome. An AUC of 0.7 was considered fair, 0.8 good, and 0.9 excellent, according to established cut-offs.

RESULTS

A total of 581 patients (59% female) were available for analysis. Of those, 140 (24.1%) were converted to inpatient status. The median age was 51 (IQR 44-59), and the median BMI was 28 kg/m2 (IQR 24-32). The XGBoost model showed the best performance with an AUC of 0.79. The most important features were the length of the operation, followed by sex (based on biological attributes), age, and operation start time. The logistic regression model and the SVM showed worse results, with an AUC of 0.71 each.

CONCLUSIONS

This study demonstrated a novel approach to predicting conversion to inpatient status in eligible patients for ambulatory surgery. The XGBoost model showed good predictive capabilities, superior to the older machine learning approaches. This model also revealed the importance of surgical duration time, BMI, and age as risk factors for patient conversion. A developing field of study is using machine learning in clinical decision-making. Our findings contribute to this field by demonstrating the feasibility and accuracy of such methods in predicting outcomes and identifying risk factors, although external and multi-center validation studies are needed.

Risk Factors for Unexpected Conversion From Ambulatory to Inpatient Admission Among One-level or Two-level ACDF Patients

STUDY DESIGN/SETTING

A retrospective observational study.

OBJECTIVE

The aim of this study was to investigate the factors associated with the conversion of patient status from ambulatory anterior cervical discectomy and fusion (ACDF) to inpatient.

SUMMARY OF BACKGROUND DATA

Surgeries are increasingly performed in an ambulatory setting in an era of rising healthcare costs and pressure to improve patient satisfaction. ACDF is a common ambulatory cervical spine surgery, however, there are certain patients who are unexpectedly converted from an outpatient procedure to inpatient admission and little is known about the risk factors for conversion.

MATERIALS AND METHODS

Patients who underwent one-level or two-level ACDF in an ambulatory setting at a single specialized orthopedic hospital between February 2016 to December 2021 were included. Baseline demographics, surgical information, complications, and conversion reasons were compared between patients with ambulatory surgery or observational stay (stay <48 h) and inpatient (stay >48 h).

RESULTS

In total, 662 patients underwent one-level or two-level ACDF (median age, 52 yr; 59.5% were male), 494 (74.6%) patients were discharged within 48 hours and 168 (25.4%) patients converted to inpatient. Multivariable logistic regression analysis demonstrated that females, low body mass index <25, American Society of Anesthesiologists classification (ASA) ≥3, long operation, high estimated blood loss, upper-level surgery, two-level fusion, late operation start time, and high postoperative pain score were considered independent risk factors for conversion to inpatient. Pain management was the most common reason for the conversion (80.0%). Ten patients (1.5%) needed reintubation or remained intubated for airway management.

CONCLUSIONS

Several independent risk factors for prolonged hospital stay after ambulatory ACDF surgery were identified. Although some factors are unmodifiable, other factors, such as procedure duration, operation start time, and blood loss could be potential targets for intervention. Surgeons should be aware of the potential for life-threatening airway complications in ambulatory-scheduled ACDF.

Patient Selection Criteria in Ambulatory Spine Surgery: Single Canadian Provincial Experience

BACKGROUND

Ambulatory spinal surgery is a care delivery model meant to improve patient outcomes and reduce in-hospital length of stay (LOS). We reviewed the experience of implementing an outpatient spine surgery program in Manitoba, Canada and highlight elements that can be used to reduce LOS and re-presentation to hospital.

METHODS

This is a retrospective cohort study using data from the Canadian Spine Outcomes and Research Network and independent chart review of adult patients undergoing outpatient spinal surgery between 2015 and 2018. Patient demographics, comorbidities, perioperative course, LOS, and readmissions were analyzed.

RESULTS

We included 217 patients in this analysis. The mean LOS was 36.2 hours; 71.98% of patients had a LOS <24 hours. A Kruskal-Wallis test by ranks analysis was conducted and identified 7 elements that correlated with prolonged length of stay (>1 day): age older than 55 (P = 0.027), body mass index >25 (P = 0.045), uncontrolled diabetes (P = 0.015), preoperative use of opioid medication (P = 0.024), American Society of Anesthesiologists classification of 3 (P = 0.023), non-minimally invasive surgical approach, and multilevel procedures. Most (94.1%) of the patients with none of these elements (i.e., age <55, low body mass index, normal/controlled diabetes, minimal preoperative opioid use, American Society of Anesthesiologist classification <3, minimally invasive surgical procedure) had a favorable LOS, <24 hours, compared with 84.8% with 1 risk factor, 80.4% of those with two, 69.8% with three, 53.1% with four, and 31.2% with 5 or more. A small number of patients (14.98%) presented to an emergency department within 90 days of their operation, and there was a 6.28% readmission rate.

CONCLUSIONS

We identified several patient and surgical criteria that correlate with prolonged length of stays following planned ambulatory spine surgery. Our work provides some empiric evidence to help guide surgeons on which patients and approaches are ideal for ambulatory surgery.

The use of machine learning for predicting candidates for outpatient spine surgery: a review

While spine surgery has historically been performed in the inpatient setting, in recent years there has been growing interest in performing certain cervical and lumbar spine procedures on an outpatient basis. While conducting these procedures in the outpatient setting may be preferable for both the surgeon and the patient, appropriate patient selection is crucial. The employment of machine learning techniques for data analysis and outcome prediction has grown in recent years within spine surgery literature. Machine learning is a form of statistics often applied to large datasets that creates predictive models, with minimal to no human intervention, that can be applied to previously unseen data. Machine learning techniques may outperform traditional logistic regression with regards to predictive accuracy when analyzing complex datasets. Researchers have applied machine learning to develop algorithms to aid in patient selection for spinal surgery and to predict postoperative outcomes. Furthermore, there has been increasing interest in using machine learning to assist in the selection of patients who may be appropriate candidates for outpatient cervical and lumbar spine surgery. The goal of this review is to discuss the current literature utilizing machine learning to predict appropriate patients for cervical and lumbar spine surgery, candidates for outpatient spine surgery, and outcomes following these procedures.

The Influence of Workers' Compensation Status on Patient-Reported Outcomes after Cervical Disc Arthroplasty at an Ambulatory Surgical Center

INTRODUCTION

Workers' compensation (WC) status tends to negatively affect patient outcomes in spine surgery. This study aims to evaluate the potential effect of WC status on patient-reported outcomes (PROs) after cervical disc arthroplasty (CDR) at an ambulatory surgical center (ASC).

METHODS

A single-surgeon registry was retrospectively reviewed for patients who had undergone elective CDR at an ASC. Patients with missing insurance data were excluded. Propensity score-matched cohorts were generated by the presence or lack of WC status. PROs were collected preoperatively and at 6-week, 12-week, 6-month, and 1-year time points. PROs included the Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF), visual analog scale (VAS) neck and arm pain, and Neck Disability Index. PROs were compared within and between groups. Minimum clinically important difference (MCID) achievement rates were compared between groups.

RESULTS

Sixty-three patients were included, with 36 without WC (non-WC) and 27 with WC. The non-WC cohort demonstrated postoperative improvement in all PROs at all time points, with the exception of VAS arm past the 12-week point ( P ≤ 0.030, all). The WC cohort demonstrated postoperative improvement in VAS neck at 12-week, 6-month, and 1-year time points ( P ≤ 0.025, all). The WC cohort improved in VAS arm and Neck Disability Index at the 12-week and 1-year points as well ( P ≤ 0.029, all). The non-WC cohort reported superior PRO scores in every PRO at one or more postoperative time points ( P ≤ 0.046, all). The non-WC cohort demonstrated higher rates of minimum clinically important difference achievement in PROMIS-PF at 12 weeks ( P ≤ 0.024).

CONCLUSION

Patients with WC status undergoing CDR at an ASC may report inferior pain, function, and disability outcomes compared with those with private or government-provided insurance. Perceived inferior disability in WC patients persisted into the long-term follow-up period (1 year). These findings may aid surgeons in setting realistic preoperative expectations with patients at risk of inferior outcomes.

Risk stratification of patients undergoing outpatient lumbar decompression surgery

BACKGROUND CONTEXT

Reimbursement has slowly transitioned from a fee-for-service model to a bundled payment model after introduction of the United States Centers for Medicare and Medicaid Services bundled payment program. To minimize healthcare costs, some surgeons are trying to minimize healthcare expenditures by transitioning appropriately selected lumbar decompression patients to outpatient procedure centers.

PURPOSE

To prepare a risk stratification calculator based on machine learning algorithms to improve surgeon's preoperative predictive capability of determining whether a patient undergoing lumbar decompression will meet inpatient vs. outpatient criteria. Inpatient criteria was defined as any overnight hospital stay.

STUDY DESIGN/SETTING

Retrospective single-institution cohort.

PATIENT SAMPLE

A total of 1656 patients undergoing primary lumbar decompression.

OUTCOME MEASURES

Postoperative outcomes analyzed for inclusion into the risk calculator included length of stay.

METHODS

Patients were split 80-20 into a training model and a predictive model. This resulted in 1,325 patients in the training model and 331 into the predictive model. A logistic regression analysis ensured proper variable inclusion into the model. C-statistics were used to understand model effectiveness. An odds ratio and nomogram were created once the optimal model was identified.

RESULTS

A total of 1,656 patients were included in our cohort with 1,078 dischared on day of surgery and 578 patients spending ≥ 1 midnight in the hospital. Our model determined older patients (OR=1.06, p<.001) with a higher BMI (OR=1.04, p<0.001), higher back pain (OR=1.06, p=.019), increasing American Society of Anesthesiologists (ASA) score (OR=1.39, p=.012), and patients with more levels decompressed (OR=3.66, p<0.001) all had increased risks of staying overnight. Patients who were female (OR=0.59, p=.009) and those with private insurance (OR=0.64, p=.023) were less likely to be admitted overnight. Further, weighted scores based on training data were then created and patients with a cumulative score over 118 points had a 82.9% likelihood of overnight. Analysis of the 331 patients in the test data demonstrated using a cut-off of 118 points accurately predicted 64.8% of patients meeting inpatient criteria compared to 23.0% meeting outpatient criteria (p<0.001). Area under the curve analysis showed a score greater than 118 predicted admission 81.4% of the time. The algorithm was incorporated into an open access digital application available here: https://rothmanstatisticscalculators.shinyapps.io/Inpatient_Calculator/?_ga=2.171493472.1789252330.1671633274-469992803.1671633274 CONCLUSIONS: Utilizing machine-learning algorithms we created a highly reliable predictive calculator to determine if patients undergoing outpatient lumbar decompression would require admission. Patients who were younger, had lower BMI, lower preoperative back pain, lower ASA score, less levels decompressed, private insurance, lived with someone at home, and with minimal comorbidities were ideal candidates for outpatient surgery.

Ambulatory Lumbar Fusion: A Systematic Review of Perioperative Protocols, Patient Selection Criteria, and Outcomes

STUDY DESIGN/SETTING

Systematic review.

OBJECTIVE

The primary purpose was to propose patient selection criteria and perioperative best practices that can serve as a starting point for an ambulatory lumbar fusion program. The secondary purpose was to review patient-reported outcomes (PROs) after ambulatory lumbar fusion.

SUMMARY OF BACKGROUND

As healthcare costs rise, there is an increasing emphasis on cost saving strategies (i.e. outpatient/ambulatory surgeries). Lumbar fusion procedures remain a largely inpatient surgery. Early studies have shown that fusion procedures can be safely preformed in an outpatient setting but no review has summarized these findings and best practices.

MATERIALS AND METHODS

This study was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed/MEDLINE, The Cochrane Library, and Embase were searched. The following data were collected: (1) study design; (2) number of participants; (3) patient population; (4) procedure types; (5) procedure setting; (6) inclusion criteria; (7) protocols; (8) adverse events; (9) PROs; and (10) associations between patient/surgical factors, setting, and outcomes.

RESULTS

The search yielded 20 publications. The following selection criteria for ambulatory lumbar fusion were identified: age below 70, minimal comorbidities, low/normal body mass index, no tobacco use, and no opioid use. The perioperative protocol can include a multimodal analgesic regimen. The patient should be observed for at least three hours after surgery. The patient should not be discharged without an alertness check and a neurological examination. Patients experienced significant improvements in PROs after ambulatory lumbar fusion; similarly, when compared to an inpatient group, ambulatory lumbar fusion patients experienced a comparable or superior improvement in PROs.

CONCLUSION

There are two critical issues surrounding ambulatory lumbar fusion: (1) Who is the ideal patient, and (2) What needs to be done to enable expedited discharge? We believe this review will provide a foundation to assist surgeons in making decisions regarding the performance of lumbar fusion on an ambulatory basis.

LEVEL OF EVIDENCE

Level III.

The Effect of the Coronavirus Disease 2019 (COVID-19) Pandemic on Elective Cervical Spine Surgery Utilization and Complications in the United States: A Nationwide Temporal Trends Analysis

OBJECTIVES

As a result of the coronavirus disease 2019 (COVID-19) pandemic, elective surgeries nationwide were suspended. The objective was to compare temporal trends in patient demographics, case volumes, and postoperative complications of patients undergoing elective cervical spine surgery from pre-COVID-19 (2019-2020 Q1) to post-COVID-19 (2020 Q2-Q4).

METHODS

The 2019 to 2020 American College of Surgeon's National Surgery Quality Improvement Program database was queried for common elective cervical spine surgeries. Patients pre-COVID-19 (2019-2020 Q1) were compared with those undergoing surgery during post-COVID-19 (2020 Q2-Q4) protocols. Procedural use, patient demographics, and complications were compared. Linear regression was used to evaluate case volume changes over time. P values less than 0.05 were significant.

RESULTS

In total, 31,013 patients underwent elective cervical spine surgery in 2019 (N = 16,316) and 2020 (N = 14,697); an overall 10% decline. Compared with the calendar year 2019 through 2020 Q1 mean, elective surgery volume decreased by 21.6% in 2020 Q2 and never returned to prepandemic baseline. The percentage decline in case volume from 2019 to 2020 Q1 to 2020 Q2 was greatest for anterior cervical discectomy and fusion (23.3%), followed by cervical decompression (23.4%), posterior cervical fusion (15.0%), and cervical disc arthroplasty and vertebral corpectomy (13.7%). Patients undergoing surgery in 2020 Q2-Q4 had overall greater comorbidity burden (American Society of Anesthesiologists grade 3 and 4) (P < 0.001). From 2019-2020 Q1 versus 2020 Q2-Q4, there was a significant increase in total complication (5.5% vs. 6.8%, P < 0.001), reoperation (1.9% vs. 2.2%, P = 0.048), and mortality (0.25% vs. 0.37%, P = 0.049) rates.

CONCLUSIONS

Elective surgery declined drastically during the second quarter of 2020. Patients undergoing surgery during the pandemic had an overall greater comorbidity burden, resulting in increased total complication and mortality rates over the study period.

Impact of age within younger populations on outcomes following cervical surgery in the ambulatory setting

Objective

To determine the effect of age within the younger population seen at ambulatory surgical centers on patient-reported outcome measures (PROMs) after cervical spine surgery.

Methods

Patients of age <65 years undergoing single-level anterior cervical discectomy and fusion (ACDF) or cervical disc replacement (CDR) were included. Patients were divided by mean age of initial population (46 years). PROMs included Patient-reported Outcome Measurement Information System Physical Function (PROMIS-PF), 12-Item Short-Form Physical Component Survey (SF-12 PCS), Visual Analog Scale (VAS) neck, VAS arm, Neck Disability Index (NDI) collected preoperatively and at postoperative time points up to 2 years.

Results

138 patients were included, with 66 patients <46 years. Both cohorts demonstrated improvement from preoperative baseline with regard to all studied PROMs at multiple time points postoperatively (p ≤ 0.042, all). Between groups, the older cohort demonstrated greater mean PROMIS-PF scores preoperatively and at 6 weeks (p ≤ 0.011, both), while VAS arm scores were lower in the older group at 1 year (p = 0.002), and NDI scores were lower in the older group at 6 weeks and 1 year (p < 0.027, both). Minimal Clinically Important Difference (MCID) achievement rates were greater in the younger group in PROMIS PF at 2 years (p = 0.002), and in the older group in VAS arm score at 1 year (p = 0.007).

Conclusion

Both cohorts showed significant improvement at multiple postoperative time points for all PROMs. Between groups, the older group reported more favorable physical function, VAS arm, and NDI scores at several time points. However, MCID achievement rates only significantly differed in two PROMs at singular time points. Difference in age in patients <65 years likely does not significantly affect long-term outcomes after cervical spine surgery.

Ambulatory Single-level Posterior Cervical Foraminotomy for Cervical Radiculopathy: A Propensity-matched Analysis of Complication Rates

STUDY DESIGN

Retrospective cohort comparison study.

OBJECTIVE

The aim was to compare perioperative complications and 30-day readmission between ambulatory and inpatient posterior cervical foraminotomy (PCF) in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database.

SUMMARY OF BACKGROUND DATA

Single-level PCF for cervical radiculopathy is increasingly being performed as an ambulatory procedure. Despite this increase, there is a lack of published literature documenting the safety of ambulatory PCF.

MATERIALS AND METHODS

Patients who underwent PCF (through laminotomy or laminectomy) were identified in the 2005-2018 NSQIP database. Ambulatory procedures were defined as cases that had hospital length of stay=0 days. Inpatient procedures were defined as cases that had length of stay=1-4 days. Patient characteristics, comorbidities, and procedural variables (laminotomy or laminectomy performed) were compared between the 2 cohorts. Propensity score matched comparisons were then performed for postoperative complications and 30-day readmissions between the 2 groups.

RESULTS

In total, 795 ambulatory and 1789 inpatient single-level PCF cases were identified. After matching, there were 795 ambulatory and 795 inpatient cases. Statistical analysis after propensity score matching revealed no significant difference in individual complications including 30-day readmission, thromboembolic events, wound complications, and reoperation, or aggregated complications between ambulatory versus matched inpatient procedures. Overall 30-day readmissions after ambulatory single-level PCF were noted for 2.46% of the study population, and the most common reasons were surgical site infections (46%) and pain control (15%).

CONCLUSIONS

The perioperative outcomes assessed in this study support the conclusion that single-level PCF for cervical radiculopathy can be performed for correctly selected patients in the ambulatory setting without increased rates of 30-day perioperative complications or readmissions compared with inpatient procedures.

LEVEL OF EVIDENCE

Level III.

Impact of Surgeon Experience on Outcomes of Anterior Cervical Discectomy and Fusion

INTRODUCTION

The relationship between surgeon experience and cervical fusion outcomes has yet to be assessed. We investigate perioperative characteristics, patient-reported outcomes (PROMs), and minimal clinically important difference (MCID) achievement after anterior cervical diskectomy and fusion (ACDF) by the volume of cases done throughout an orthopaedic spine surgeon's career.

METHODS

ACDF procedures between 2005 and 2020 were identified. Group I included the first half of ACDF cases (#1-#321). PROMs were introduced in the second half of the ACDF cases; thus, the next 322 cases were subdivided to compare PROM and MCID between subgroups (cases #322 to #483 = group II and #484 to #645 = group III). PROMs, including VAS back/leg, Oswestry Disability Index (ODI), Short Form-12 Physical Composite Score, and PROMIS-PF, were collected preoperatively/postoperatively. Demographics, perioperative variables, mean PROMs, and MCID achievement were compared between groups and subgroups using the Student t-test and chi-square. Logistic regression evaluated MCID achievement using the established threshold values.

RESULTS

A total of 642 patients were included (320 in group I, 161 in group II, and 161 in group III). The latter cases had significantly decreased surgical time, blood loss, and postoperative length of stay in comparison of groups and subgroups (P ≤ 0.002, all). CT-confirmed 1-year arthrodesis rates were increased among the latter cases (P = 0.045). Group II had significantly higher arthrodesis rates than group III (P = 0.039). The postoperative complication rates were lower in the latter cases (P < 0.001, all), whereas subgroup analysis revealed lower incidence of urinary retention and other complications in group III (P ≤ 0.031, all). Mean PROMs were significantly inferior in group II versus group III for VAS neck at 6 months (P = 0.030), Neck Disability Index at 6 months preoperatively (P ≤ 0.022, both), Short Form-12 Physical Composite Score at 12 weeks/2 years (P ≤ 0.047, both), and PROMIS-PF at 12 weeks/6 months (P ≤ 0.036, both). The MCID attainment rates were higher among group III for VAS neck/Neck Disability Index at 2 years (P ≤ 0.005) and overall achievement across all PROMs (P ≤ 0.015, all).

DISCUSSION

Increased ACDF case volume may lead to markedly decreased surgical time, blood loss, and length of postoperative stay as well as improved clinical outcomes in pain, disability, and physical function.

Dysphagia and Satisfaction Following Anterior Cervical Spine Surgery: A Prospective Observation Trial

STUDY DESIGN

Prospective observation.

OBJECTIVE

To assess the effect of dysphagia on patient satisfaction following anterior cervical discectomy and fusion.

BACKGROUND

Difficulty with swallowing is a common complaint following anterior cervical spine surgery. The exact impact of this issue on the patient's overall satisfaction is unknown because of its often-transient nature.

MATERIALS AND METHODS

A prospective evaluation of all patients from a single surgeon undergoing an anterior cervical spine surgery. Dysphagia was evaluated both preoperatively and postoperatively at set intervals via a combination of 3 validated scoring systems. Mean satisfaction scores at 6 months was evaluated at 6 months via modified CSRS survey. Comparative analysis was performed to determine if there was any relationship between the 2 outcomes.

RESULTS

A total of 96.77% (68/71) of enrolled patients completed all of their follow-up surveys. The prevalence of dysphagia was 32.4% at 2 weeks after surgery, 20.6% at 6 weeks, 13.2% at 3 months, and 13.2% at 6 months. In total, 82.35% (56/68) of patients were satisfied with their surgical outcome and only 5.88% (4/68) were dissatisfied with their outcome. There was no relationship between a patient's overall satisfaction level and the presence of dysphagia at any postoperative interval. The absence of neck pain at 6 months was the only significant predictor of patient satisfaction (P=0.003).

CONCLUSION

Dysphagia is a common but often transient complaint following anterior cervical spine surgery. Fortunately, its presence does not seem to correlate with a patient's overall satisfaction level following surgery.

LEVEL OF EVIDENCE

Level I.

Early Opioid Consumption Patterns After Anterior Cervical Spine Surgery

STUDY DESIGN

This is a prospective observational study.

OBJECTIVE

The aim was to record daily opioid use and pain levels after 1-level or 2-level anterior cervical discectomy and fusion (ACDF) or cervical disc arthroplasty (CDA).

SUMMARY OF BACKGROUND DATA

Data to inform opioid prescription guidelines following ACDF or CDA is lacking. Understanding postoperative opioid consumption behaviors is critical to provide appropriate postdischarge prescriptions.

METHODS

Patients undergoing 1-level or 2-level primary ACDF or CDA were consecutively enrolled at 2 participating institutions between March 2018 and March 2019. Patients with opioid dependence (defined as daily use ≥6 mo before surgery) were excluded. Starting postoperative day 1, daily opioid use and numeric pain rating scale pain levels were collected through a Health Insurance Portability and Accountability Act-compliant, automated text-messaging system. To facilitate clinical applications, opioid use was converted from oral morphine equivalents into "pills" (oxycodone 5 mg equivalents). After 6 weeks or upon patient-reported cessation of opioid use, final survey questions were asked. Refill data were verified from the state prescription registry. Risk factors for patients in top quartile of consumption were analyzed.

RESULTS

Of 57 patients, 48 completed the daily queries (84.2%). Mean age of the patient sample was 50.2±10.9 years. Thirty-two patients (66.7%) underwent ACDF and 16 CDA (33.3%); 64.6% one level; 35.4% two levels. Median postdischarge use was 6.7 pills (range: 0-160). Cumulative opioid use did not vary between the 1-level and 2-level groups (median pill consumption, 10 interquartile range: 1.3-31.3 vs. 4 interquartile range: 0-18, respectively, P=0.085). Thirteen patients (27.1%) did not use any opioids after discharge. Of those patients that took opioids after discharge, half ceased opioids by postoperative day 8. Preoperative intermittent opioid use was associated with the top quartile of opioid consumption (9.1% vs. 50%, P=0.006).

CONCLUSION

Given that most patients use few opioids, patients could be offered the option of a 12 oxycodone 5 mg (90 oral morphine equivalents) discharge prescription, accompanied by education on appropriate opioid use and disposal.

Association of Medicaid expansion under the Affordable Care Act with access to elective spine surgical care

OBJECTIVE

The Affordable Care Act expanded Medicaid eligibility in many states, improving access to some forms of elective healthcare in the United States. Whether this effort increased access to elective spine surgical care is unknown. This study's objective was to evaluate the impact of Medicaid expansion under the Affordable Care Act on the volume and payer mix of elective spine surgery in the United States.

METHODS

This study evaluated elective spine surgical procedures performed from 2011 to 2016 and included in the all-payer State Inpatient Databases of 10 states that expanded Medicaid access in 2014, as well as 4 states that did not expand Medicaid access. Adult patients aged 18-64 years who underwent elective spine surgery were included. The authors used a quasi-experimental difference-in-difference design to evaluate the impact of Medicaid expansion on hospital procedure volume and payer mix, independent of time-dependent trends. Subgroup analysis was conducted that stratified results according to cervical fusion, thoracolumbar fusion, and noninstrumented surgery.

RESULTS

The authors identified 218,648 surgical procedures performed in 10 Medicaid expansion states and 118,693 procedures performed in 4 nonexpansion states. Medicaid expansion was associated with a 17% (95% CI 2%-35%, p = 0.03) increase in mean hospital spine surgical volume and a 23% (95% CI -0.3% to 52%, p = 0.054) increase in Medicaid volume. Privately insured surgical volumes did not change significantly (incidence rate ratio 1.13, 95% CI -5% to 34%, p = 0.18). The increase in Medicaid volume led to a shift in payer mix, with the proportion of Medicaid patients increasing by 6.0 percentage points (95% CI 4.1-7.0, p < 0.001) and the proportion of private payers decreasing by 6.7 percentage points (95% CI 4.5-8.8, p < 0.001). Although the magnitude of effects varied, these trends were similar across procedure subgroups.

CONCLUSIONS

Medicaid expansion under the Affordable Care Act was associated with an economically and statistically significant increase in spine surgery volume and the proportion of surgical patients with Medicaid insurance, indicating improved access to care.

Effectiveness of a Fully Impregnated Hydroxyapatite Polyetheretherketone Cage on Fusion in Anterior Cervical Spine Surgery

Introduction Anterior cervical discectomy and fusion (ACDF) is the gold standard for the treatment of cervical spondylosis. However, new techniques, technologies, and improved implants have aided surgeons in reducing operative time with enhanced patient outcomes. Impregnated hydroxyapatite polyetheretherketone (HA PEEK) cages (Arena-C HA®, LESspine Inc. Malden, MA) are one such option that has aimed to increase the fusion rate. The authors herein aimed to assess the use of HA PEEK interbody cages by looking at outcomes, complications, and radiographic fusion.  Methods The medical records of 41 consecutive patients undergoing single-level ACDF with impregnated HA PEEK cages (group 1) were compared to the control group of 47 patients who had single-level ACDF without impregnated HA PEEK cages (group 2). Outcomes assessed included Visual Analog Scale (VAS) neck, Neck Disability Index (NDI) scores, radiographic fusion, and complication rates.  Results Of the 41 patients in group 1 (HA PEEK), 48% were female population with a mean age of 58.5+/- 1.7 years and BMI 29.7+/-1.2 kg/m². Of the 47 patients in group 2 (non-HA PEEK), 53% were female with a mean age of 54.3+/- 1.2 years and BMI 27.8+/-0.8 kg/m². Using t-test, there was a statistically significant intergroup difference in two-year VAS neck and NDI scores, p=0.007, and p=0.001, respectively. Radiographic fusion occurred as early as three months in the HA PEEK group.  Conclusions This study has demonstrated the equivalence of impregnated HA PEEK cages in single-level ACDF. Significant improvements were seen in VAS and NDI scores in the HA PEEK group. There was no incidence of heterotopic bone formation or reaction to HA PEEK cages. Additionally, a trend toward fusion was seen in HA PEEK patients as early as three to five months compared to seven to eight months for the ACDF group. We conclude that HA PEEK cages can be safely placed with excellent outcomes. However, further studies are required to look at added benefits.

Administrative Data Are Unreliable for Ranking Hospital Performance Based on Serious Complications After Spine Fusion

STUDY DESIGN

Retrospective analysis of administrative billing data.

OBJECTIVE

To evaluate the extent to which a metric of serious complications determined from administrative data can reliably profile hospital performance in spine fusion surgery.

SUMMARY OF BACKGROUND DATA

While payers are increasingly focused on implementing pay-for-performance measures, quality metrics must reliably reflect true differences in performance among the hospitals profiled.

METHODS

We used State Inpatient Databases from nine states to characterize serious complications after elective cervical and thoracolumbar fusion. Hierarchical logistic regression was used to risk-adjust differences in case mix, along with variability from low case volumes. The reliability of this risk-stratified complication rate (RSCR) was assessed as the variation between hospitals that was not due to chance alone, calculated separately by fusion type and year. Finally, we estimated the proportion of hospitals that had sufficient case volumes to obtain reliable (>0.7) complication estimates.

RESULTS

From 2010 to 2017 we identified 154,078 cervical and 213,133 thoracolumbar fusion surgeries. 4.2% of cervical fusion patients had a serious complication, and the median RSCR increased from 4.2% in 2010 to 5.5% in 2017. The reliability of the RSCR for cervical fusion was poor and varied substantially by year (range 0.04-0.28). Overall, 7.7% of thoracolumbar fusion patients experienced a serious complication, and the RSCR varied from 6.8% to 8.0% during the study period. Although still modest, the RSCR reliability was higher for thoracolumbar fusion (range 0.16-0.43). Depending on the study year, 0% to 4.5% of hospitals had sufficient cervical fusion case volume to report reliable (>0.7) estimates, whereas 15% to 36% of hospitals reached this threshold for thoracolumbar fusion.

CONCLUSION

A metric of serious complications was unreliable for benchmarking cervical fusion outcomes and only modestly reliable for thoracolumbar fusion. When assessed using administrative datasets, these measures appear inappropriate for high-stakes applications, such as public reporting or pay-for-performance.Level of Evidence: 3.

Association of Duration of Preoperative Opioid Use with Reoperation After One-level Anterior Cervical Discectomy and Fusion in Nonmyelopathic Patients

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of this study was to determine that rates of preoperative opioid use in patients undergoing single-level anterior discectomy and fusion (ACDF) without myelopathy and determine the association with reoperations over 5 years.

SUMMARY OF BACKGROUND DATA

Preoperative opioid use before cervical spine surgery has been linked to worse postoperative outcomes. However, no studies have determined the association of duration and type of opioid used with reoperations after ACDF.

METHODS

Patients undergoing single-level ACDF without myelopathy between 2007 and 2016 with at least 5-year follow-up were identified in one private insurance administrative database. Preoperative opiate use was divided into acute (within 3 months), subacute (acute use and use between 3 and 6 months), and chronic (subacute use and use before 6 months) and by the opiate medication prescribed (tramadol, oxycodone, and hydrocodone). Postoperative rates of additional cervical spine surgery were determined at 5 years and multivariate logistic regression was used to determine the association of preoperative opiates with additional surgery.

RESULTS

Of 445 patients undergoing single-level ACDF without myelopathy, 66.3% were taking opioid medications before surgery. The most commonly used preoperative opioid was hydrocodone (50.3% acute use, 24.7% chronic use). Opioid-naïve patients had a 5-year reoperation rate of 4.7%, compared to 25.0%, 15.5%, and 23.3% with chronic preoperative use of tramadol, hydrocodone, and oxycodone. In multivariate analysis, controlling for age, sex, and Charlson Comorbidity Index, chronic use of hydrocodone (odds ratio [OR] = 2.08, P = 0.05), oxycodone (OR = 4.46, P < 0.01), and tramadol (OR = 4.01, P = 0.01) were all associated with increased reoperations. However, acute use of hydrocodone, oxycodone, and tramadol was not associated with reoperations (P > 0.05).

CONCLUSION

Both subacute and chronic use of common lower-dose opioid medications is associated with increased reoperations after single-level ACDF in nonmyelopathic patients. This information is critical when counseling patients preoperatively and developing preoperative opioid cessation programs.Level of Evidence: 3.

Outcomes of Same-Day Orthopedic Surgery: Are Spine Patients More Likely to Have Optimal Immediate Recovery From Outpatient Procedures?

BACKGROUND

Spinal surgery is associated with an inherently elevated risk profile, and thus far there has been limited discussion about how these outpatient spine patients are benefiting from these same-day procedures against other typical outpatient orthopedic surgeries.

METHODS

Orthopedic patients who received either inpatient or outpatient surgery were isolated in the American College of Surgeons National Surgical Quality of Improvement Program (2005-2016). Patients were stratified by type of orthopedic surgery received (spine, knee, ankle, shoulder, or hip). Mean comparisons and chi-squared tests assessed basic demographics. Perioperative complications were analyzed via regression analyses in regard to their principal inpatient or outpatient orthopedic surgery received.

RESULTS

This study included 729 480 surgical patients: 32.5% received spinal surgery, 36.5% knee, 24.1% hip, 4.9% shoulder, and 1.7%ankle. Of those who received a spinal procedure, 74.7% were inpatients (IN), and 25.3% were outpatients (OUT): knee: 96.1% IN, 3.9% OUT; hip:98.9% IN, 1.1% OUT; ankle: 29% IN, 71% OUT; and shoulder: 52.6% IN, 47.6% OUT. Hip patients were the oldest, and knee patients had the highest body mass index out of the orthopedic groups (P < .00). Spine IN patients experienced more complications than the other orthopedic groups and had the lowest OUT complications(both P < .05). This same trend of having higher IN complications than OUT complications was identified for hip, shoulder, and knee. However, ankle procedures had greater OUT procedure complications than IN (P < .05). After controlling for age, body mass index, and Charlson Comorbidity Index, IN procedures, such as knee, hip, spine, and shoulder, were significantly associated with experiencing postoperative complications. From 2006 to 2016, IN and OUT surgeries were significantly different among complications experienced for all of the orthopedic groups (P < .05) with complications decreasing for IN and OUT patients by 2016.

CONCLUSIONS

Over the past decade, spine surgery has decreased in complications for IN and OUT procedures along with IN/OUT knee, ankle, hip, and shoulder procedures, reflecting greater tolerance for risk in an outpatient setting.

LEVEL OF EVIDENCE

3.

CLINICAL RELEVANCE

Despite the increase in riskier spine procedures, complications have decreased over the years. Surgeons should aim to continue to decrease inpatient spine complications to the level of other orthopedic surgeries.

The Expanding Frontier of Outpatient Spine Surgery

BACKGROUND

In 2014, inpatient spinal fusion surgery had the highest aggregate cost of any inpatient surgery performed in the United States, costing 12 billion dollars. As the national health care system seeks to improve value-based care, there is increased motivation to perform surgery on an outpatient basis. To ensure improved patient outcomes with this transition, patient selection has become increasingly important to identify who would most benefit from outpatient spine fusion, for example. This demands an improved understanding of the demographics of patients who have been receiving outpatient spine fusion on which the spine surgery community can build to improve cost-effective care delivered.

METHODS

The Healthcare Cost and Utilization Project, State Ambulatory Surgery Databases, and Agency for Healthcare Research and Quality databases were queried for demographic data regarding all-cause outpatient spine surgery between 2012 and 2014. Outpatient surgery volume was compared with inpatient surgery volume-which was provided by the State Inpatient Databases.

RESULTS

A total of 1,164,040 spine fusion procedures were identified between 2012 and 2014, of which 132,900 procedures were performed as outpatient surgery (11.4%). Of all fusion procedures amongst 18- to 44-year-old patients, 18.4% were outpatient. A larger proportion of white patients, rather than black or Hispanic patients, underwent ambulatory procedures (12.14% vs 9.53% vs 7.46%, respectively); 16.54% of spinal fusion procedures for patients with private insurance was performed on an outpatient basis. Based on patient income, 76% of all outpatient fusions were performed on patients who live in "not low" income ZIP codes.

CONCLUSIONS

There has been a gradual trend toward performing more outpatient spinal fusion procedures over the studied period. This study has also revealed unique trends in the demographics of patients who have received outpatient spine fusion during this time.

LEVEL OF EVIDENCE

3.

Implementation of Outpatient Minimally Invasive Lumbar Decompression at an Academic Medical Center without Ambulatory Surgery Centers: A Cost Analysis and Systematic Review

BACKGROUND

Lumbar decompressions are increasingly performed at ambulatory surgery centers (ASCs). We sought to compare costs of open and minimally invasive (MIS) lumbar decompressions performed at a university without dedicated ASCs.

METHODS

Lumbar decompressions performed at a tertiary academic hospital or satellite university hospital dedicated to outpatient surgery were retrospectively reviewed. Care pathways were same-day, overnight observation, or inpatient admission. Patient demographics, American Society of Anesthesiologists classification, Charlson Comorbidity Index, surgical characteristics, 30-day readmission, and costs were collected. A systematic review of lumbar decompression cost literature was performed.

RESULTS

A total of 354 patients, mean age 55 years with 128 women (36.2%), were reviewed. There was no significant difference in age, gender, body mass index, American Society of Anesthesiologists classification, or Charlson Comorbidity Index between patients treated with open and minimally invasive surgery. Open decompression was associated with higher total cost ($21,280 vs. $14,407; P < 0.001); however, this was driven by care pathway and length of stay. When stratifying by care pathway, there was no difference in total cost between open versus minimally invasive surgery among same-day ($10,609 vs. $11,074; P = 0.556), overnight observation ($14,097 vs. $13,992; P = 0.918), or inpatient admissions ($24,507 vs. $27,929; P = 0.311).

CONCLUSIONS

When accounting for care pathway, the cost of open and MIS decompression were no different. Transition from a tertiary academic hospital to a university hospital specializing in outpatient surgery was not associated with lower costs. Academic departments may consider transitioning lumbar decompressions to a dedicated ASC to maximize cost savings; however, additional studies are needed.

Patient Risk Factors Associated With 30- and 90-Day Readmission After Cervical Discectomy: A Nationwide Readmission Database Study

STUDY DESIGN

This is a retrospective cohort study.

OBJECTIVE

The aim of this study was to assess the patient-level risk factors associated with 30- and 90-day unplanned readmissions following elective anterior cervical decompression and fusion (ACDF) or cervical disk arthroplasty (CDA).

SUMMARY OF BACKGROUND DATA

For cervical disk pathology, both ACDF and CDA are increasingly performed nationwide. However, relatively little is known about the adverse complications and rates of readmission for ACDF and CDA.

METHODS

A retrospective cohort study was performed using the Nationwide Readmission Database from the years 2013 to 2015. All patients undergoing either CDA or ACDF were identified using the International Classification of Diseases, Ninth Revision, Clinical Modification coding system. Unique patient linkage numbers were used to follow patients and to identify 30- and 31-90-day readmission rates. Patients were grouped by no readmission (Non-R), readmission within 30 days (30-R), and readmission within 31-90 days (90-R).

RESULTS

There were a total of 13,093 index admissions with 856 (6.5%) readmissions [30-R: n=532 (4.0%); 90-R: n=324 (2.5%)]. Both overall length of stay and total cost were greater in the 30-R cohort compared with 90-R and Non-R cohorts. The most prevalent 30- and 90-day complications seen among the readmitted cohorts were infection, genitourinary complication, and device complication. On multivariate regression analysis, age, Medicaid status, medium and large hospital bed size, deficiency anemia, and any complication during index admission were independently associated with increased 30-day readmission. Whereas age, large hospital bed size, coagulopathy, and any complication during the initial hospitalization were independently associated with increased 90-day readmission.

CONCLUSION

Our nationwide study identifies the 30- and 90-day readmission rates and several patient-related risk factors associated with unplanned readmission after common anterior cervical spine procedures.

LEVEL OF EVIDENCE

Level III.

Economics of Cervical Disc Replacement

BACKGROUND

Although extensive reports of clinical outcome after cervical disc replacement (CDR) and anterior cervical discectomy and fusion exist, few reviews of the cost-effectiveness research in cervical spine surgery exist. The purpose of this study was to review the concepts of cost-effectiveness research, the various approaches to cost-effectiveness studies in the context of cervical spine surgery, and some of the literature results.

METHODS

Review article describing cost-effectiveness research concepts, methodology, and results. The article reviews the concept of value, cost, utility, incremental cost-effectiveness ratio, and recent research.

RESULTS

Mixed data on cost-effectiveness of CDR compared with fusion exist. Notably, several studies performed within the last 5 years that use prospectively collected utility scores, costs, and adverse event calculations demonstrate a significant cost savings associated with CDR compared with fusion.

CONCLUSIONS

The recent literature confirms that, in properly selected patients, CDR is more effective and less costly over a 7-year time horizon for patients with symptomatic degenerative disc disease. The primary driver of the differential in cost effectiveness is the difference in secondary surgery rates.

LEVEL OF EVIDENCE

Level 5 CLINICAL RELEVANCE: In properly selected patients, CDR is more effective and less costly over a 7-year time horizon for patients with symptomatic degenerative disc disease.

Safety of Outpatient Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-Analysis

BACKGROUND

Anterior cervical discectomy and fusion (ACDF) is being increasingly offered on an outpatient basis. However, the safety profile of outpatient ACDF remains poorly defined.

OBJECTIVE

To review the medical literature on the safety of outpatient ACDF.

METHODS

We systematically reviewed the literature for articles published before April 1, 2018, describing outpatient ACDF and associated complications, including incidence of reoperation, stroke, thrombolytic events, dysphagia, hematoma, and mortality. A random-effects analysis was performed comparing complications between the inpatient and outpatient groups.

RESULTS

We identified 21 articles that satisfied the selection criteria, of which 15 were comparative studies. Most of the existing studies were retrospective, with a lack of level I or II studies on this topic. We found no statistically significant difference between inpatient and outpatient ACDF in overall complications, incidence of stroke, thrombolytic events, dysphagia, and hematoma development. However, patients undergoing outpatient ACDF had lower reported reoperation rates (P < .001), mortality (P < .001), and hospitalization duration (P < .001).

CONCLUSION

Our meta-analysis indicates that there is a lack of high level of evidence studies regarding the safety of outpatient ACDF. However, the existing literature suggests that outpatient ACDF can be safe, with low complication rates comparable to inpatient ACDF in well-selected patients. Patients with advanced age and comorbidities such as obesity and significant myelopathy are likely not suitable for outpatient ACDF. Spine surgeons must carefully evaluate each patient to decide whether outpatient ACDF is a safe option. Higher quality, large prospective randomized control trials are needed to accurately demonstrate the safety profile of outpatient ACDF.

Does preventive care bundle have an impact on surgical site infections following spine surgery? An analysis of 9607 patients

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The purpose was to analyze the effect of care bundle protocol on SSI in our institution. Postoperative surgical site infections (SSI) pose significant health burden. In spite of the use of prophylactic antibiotics, surgical advances and postoperative care, wound infection continues to affect patient outcomes after spine surgery.

METHODS

Retrospective analysis of 9607 consecutive patients who underwent spine procedures from 2014 to 2018 was performed. Preventive care bundle was implemented from January 2017 consisting of (a) preoperative bundle-glycemic control, chlorhexidine gluconate (CHG) bath, (b) intra-operative bundle-time specified antibiotic prophylaxis, CHG+ alcohol-based skin preparation (c) postoperative bundle-five moments of hand hygiene, early mobilization and bundle auditing. Patients operated from January 2017 were included in the post-implementation cohort and prior to that the pre-implementation cohort was formed. Data were drawn from weekly and yearly spine audits from the hospital infection committee software. Infection data were collected based on CDC criteria, further sub classification was done based on procedure, spinal disorders and spine level. Variables were analyzed and level of significance was set as < 0.05.

RESULTS

A total of 7333 patients met the criteria. The overall SSI rate decreased from 3.42% (131/3829) in pre-implementation cohort to 1.22% (43/3504, p = 0.0001) in post-implementation cohort (RR = 2.73, OR = 2.79). Statistically significant reduction was seen in all the groups (a) superficial and deep, (b) early and late and (c) instrumented and uninstrumented groups but was more pronounced in early (p = 0.0001), superficial (p = 0.0001) and instrumented groups (p = 0.0001). On subgroup analysis based on spine level and spinal disorders, significant reduction was seen in lumbar (p = 0.0001) and degenerative group (p = 0.0001).

CONCLUSIONS

Our study revealed significant reduction of SSI secondary to strict bundle adherence and monitored compliance compared to patients who did not receive these interventions.

LEVEL OF EVIDENCE

III.

An enhanced recovery after surgery pathway: association with rapid discharge and minimal complications after anterior cervical spine surgery

OBJECTIVEEnhanced recovery after surgery (ERAS) pathways are associated with improved outcomes, lower morbidity and complications, and higher patient satisfaction in multiple surgical subspecialties. Despite these gains, there are few data to guide the application of ERAS concepts to spine surgery. The authors report the development and implementation of the first ERAS pathway for patients undergoing anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA).METHODSThis was a retrospective cohort study of prospectively collected data. The authors created a multidisciplinary pathway based on best available evidence for interventions that positively influence outcomes after anterior cervical spine surgery. Patients were followed prospectively up to postoperative day 90. Patient data were collected via electronic medical record review and included demographics, comorbidities, baseline and perioperative opioid use, postoperative complications, and length of hospital stay (LOS). ERAS process measures and compliance with pathway elements were also tracked.RESULTSThirty-three patients were cared for under the pathway (n = 25 ACDF; n = 8 CDA). The median LOS was 416 minutes (interquartile range [IQR] 210-1643 minutes). Eight patients required an extended stay-longer than 23 hours. Reasons for extended admission included pain (n = 4), dyspnea (n = 1), hypoxia (n = 1), hypertension (n = 1), and dysphagia (n = 1). The median LOS for the 8 patients who required extended monitoring prior to discharge was 1585 minutes (IQR 1423-1713 minutes). Overall pathway compliance with included process measures was 85.6%. The median number of ERAS process elements delivered to each patient was 18. There was no strong association between LOS and number of ERAS process elements provided (Pearson's r = -0.20). Twelve percent of the cohort was opioid tolerant on the day of surgery. There were no significant differences between total intraoperatively or postanesthesia care unit-administered opioid, or LOS, between opioid-tolerant and opioid-naïve patients. There were no complications requiring readmission.CONCLUSIONSAn ERAS pathway for anterior cervical spine surgery facilitates safe, prompt discharge. The ERAS pathway was associated with minimal complications, and no readmissions within 90 days of surgery. Pain and respiratory compromise were both linked with extended LOS in this cohort. Further prospective studies are needed to confirm the potential benefits of ERAS for anterior cervical spine surgery, including longer-term complications, cost, and functional outcomes.

Support for a Three-Item Questionnaire Prior to Spinal Surgery: A Health-Related Quality of Life Outcome Study

Objective  Elective lumbar and cervical operations are becoming more common in the United States. Additionally, there is a movement in the literature and clinical practice to discover short versions of longer measures as a way to anticipate an outcome. This study aims to provide neurosurgeons in practice with a three-item questionnaire that can guide referrals to psychological services presurgery. Ultimately, results could lead to an improvement in health-related quality of life (HRQoL) postspinal surgery.

Methods  This quantitative-descriptive, survey-based design with a retrospective chart review component followed 47 patients at baseline ( N = 47), 3 months ( N = 20), 6 months ( N = 31), and 1 year ( N = 19). A single item from the Coping Strategies Questionnaire, the Survey of Pain Attitudes, and the Tampa Scale of Kinesiophobia were utilized in the three-item questionnaire as a baseline measure. Patient-Reported Outcomes Measurement Information System Global Health measured HRQoL outcome at all time points. A linear regression model was conducted to predict mental health QoL postspinal surgery.

Results  This measure can predict mental health QoL outcomes up to 3-month postsurgery. Six-month and 1-year follow-ups are statistically inconclusive.

Conclusion  Individuals who are undergoing spinal surgery show lower mental health QoL outcome at baseline and 3-month postsurgery when responses on a three-item questionnaire are elevated. Limitations and future directions are discussed.

Proton Pump Inhibitor Use Affects Pseudarthrosis Rates and Influences Patient-Reported Outcomes

STUDY DESIGN

Retrospective cohort review.

OBJECTIVES

Cervical pseudarthrosis is a frequent cause of need for revision anterior cervical discectomy and fusion (ACDF) and may lead to worse patient-reported outcomes. The effect of proton pump inhibitors on cervical fusion rates are unknown. The purpose of this study was to determine if patients taking PPIs have higher rates of nonunion after ACDF.

METHODS

A retrospective cohort review was performed to compare patients who were taking PPIs preoperatively with those not taking PPIs prior to ACDF. Patients younger than 18 years of age, those with less than 1-year follow-up, and those undergoing surgery for trauma, tumor, infection, or revision were excluded. The rates of clinically diagnosed pseudarthrosis and radiographic pseudarthrosis were compared between PPI groups. Patient outcomes, pseudarthrosis rates, and revision rates were compared between PPI groups using either multiple linear or logistic regression analysis, controlling for demographic and operative variables.

RESULTS

Out of 264 patients, 58 patients were in the PPI group and 206 were in the non-PPI group. A total of 23 (8.71%) patients were clinically diagnosed with pseudarthrosis with a significant difference between PPI and non-PPI groups (P = .009). Using multiple linear regression, PPI use was not found to significantly affect any patient-reported outcome measure. However, based on logistic regression, PPI use was found to increase the odds of clinically diagnosed pseudarthrosis (odds ratio 3.552, P = .014). Additionally, clinically diagnosed pseudarthrosis negatively influenced improvement in PCS-12 scores (P = .022).

CONCLUSIONS

PPI use was found to be a significant predictor of clinically diagnosed pseudarthrosis following ACDF surgery. Furthermore, clinically diagnosed pseudarthrosis negatively influenced improvement in PCS-12 scores.

Comparison of Multilevel Anterior Cervical Discectomy and Fusion Performed in an Inpatient Versus Outpatient Setting

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To evaluate differences in patient factors, procedural factors, early outcomes and safety in mutlilevel anterior cervical discectomy and fusion (ACDF) in the inpatient versus outpatient setting.

METHODS

Patient demographics, operative factors, and outcomes of multilevel ACDF performed in an inpatient and outpatient setting were compared using Fisher's exact test for categorical and Student's t test for continuous variables.

RESULTS

Fifty-seven patients had surgery on an outpatient and 46 on an inpatient basis. Inpatients were older (56.7 vs 52.2 years, P = .012) and had a higher ASA (American Society of Anesthesiologists) class (P = .002). Sixty percent of 2-level cases were outpatient surgeries, compared with 35% of 3-level cases (P = .042). Outpatients had shorter operative times (71.26 vs 83.59 minutes, P < .0001) and shorter lengths of stay (8.51 vs 35.76 hours, P < .0001), lower blood loss (33.04 vs 45.87 mL, P = .003), and fewer in-hospital complications (5.3% vs 37.0%, P < .0001). Outpatients had better early outcomes in terms of 6-week Neck Disability Index (NDI) (27.97 vs 37.59, P = .014), visual analogue scale (VAS) neck (2.92 vs 4.02, P = .044), and Short Form-12 Physical Health Score (SF-12 PHS) (35.66 vs 30.79, P = .008). However, these differences did not persist at 6 months.

CONCLUSIONS

The results of our study suggest that multilevel ACDF can be performed safely in the outpatient setting without an increased risk of complications compared with the inpatient setting in an appropriately selected patient. Specifically, patients' age, ASA class, and number of levels being fused should be taken into consideration. At our institution, ASA class 3, body mass index >40 kg/m², age >80 years, intubation time >2.5 hours, or not having a responsible adult with the patient warrant inpatient admission. Importantly, the setting of the surgery does not affect patient-reported outcomes.

Ambulatory surgery center ownership models

Outpatient spine surgery performed in ambulatory surgery centers (ASCs) has grown dramatically over the last decade because of significant clinical and economic advantages to patients, physicians and the health care industry. Physicians benefit from the efficiencies of the outpatient setting and potential profit from ownership. There are various ownership models which differ primarily on the amount of ownership attributed to physicians, management companies and hospital systems, the key players in the space. The majority of ASCs are still solely owned by physicians, which gives physicians the benefit of maximum control but brings the challenges of management and contracting as well. Joint ventures involving various combinations of physicians, ASC management companies and hospital systems strive to find a balance between physician influence and management expertise from their partners. ASCs owned solely by hospital systems are on the rise and seek to involve physicians in a co-management role. Overall, the ASC market will continue to grow and alternative business models will arise as the key players look for the right combination to maximize efficiency and clinical success.

Spine centers of excellence: applications for the ambulatory care setting

Centers of excellence (COE) are designed to deliver high-quality, cost-effective healthcare by providing specialized and comprehensive multidisciplinary care for a given condition and have become attractive option to both insurers and healthcare providers given their promise of creating value. The criteria that constitute and define a COE may be delineated by a number of entities with a stake in value-based healthcare delivery including professional societies, the federal government, insurers and businesses seeking to control costs while guaranteeing outcomes for their employees. COEs accomplish this goal through a number of means, the first and most essential of which is centralization of organization wherein a variety of specialists are integrated under a single hospital system to improve communication between providers and decrease overall variability of care delivery. In this system, the patient is tracked throughout the entire spectrum of care from diagnosis, through non-operative or surgical intervention, and postoperative care. The centralized model in turn allows for standardization of protocols and multidisciplinary team input which helps to inform case selection, improve patient screening, make treatment more uniform and ultimately allow for dynamic and continual modification of best practices. This model lends itself particularly well to orthopedic subspecialties where patients often require specialized pre-, intra- and post-operative care from a variety of providers. However, despite their apparent benefits, studies evaluating outcomes after implementation of COEs have been less than favorable, and further research is needed in this area to support their widespread adoption. The growth of the ambulatory surgery center in orthopedics provides a new opportunity for the development, evaluation and evolution of spine COEs. Although the direct value of COEs is yet to be firmly established, they provide guidelines for best practices in outpatient spine surgery and a framework for how spine care can be transitioned safely and effectively to the outpatient setting.

Complication avoidance and management in ambulatory spine surgery

The positive safety profile and potential cost savings associated with ambulatory spine surgery have resulted in an increasing number of spine procedures being performed on an outpatient basis. As indications become more inclusive and the variety and volume of ambulatory procedures grow, the incidence of complications may rise. Limiting adverse events in the outpatient setting starts with patient selection. Surgeons should be aware of the potential complications and associated risk factors for common ambulatory spine procedures and employ strategies to limit and appropriately manage them. Protocols which include patient education, multimodal anesthesia and analgesia, standardized post-operative monitoring, and safe discharge planning are also essential for maximizing safety in the ambulatory setting.

Utilization and Outcomes for Spine Surgery in the United States and Canada

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

The aim of this study was to examine variation in spine surgery utilization between the province of Ontario and state of New York among all patients and pre-specified patient subgroups.

SUMMARY OF BACKGROUND DATA

Spine surgery is common and costly. Within-country variation in utilization is well studied, but there has been little exploration of variation in spine surgery utilization between countries.

METHODS

We used population-level administrative data from Ontario (years 2011-2015) and New York (2011-2014) to identify all adults who underwent inpatient spinal decompression or fusion surgery using relevant procedure codes. Patients were stratified according to age and surgical urgency (elective vs. emergent). We calculated standardized utilization rates (procedures per-10,000 population per year) for each jurisdiction. We compared Ontario and New York with respect to patient demographics and the percentage of hospitals performing spine surgery. We compared utilization rates of spinal decompression and fusion surgery in Ontario and New York among all patients and after stratifying by surgical urgency and patient age.

RESULTS

Patients in Ontario were older than patients in New York for both decompression (mean age 58.8 vs. 51.3 years; P < 0.001) and fusion (58.1 vs. 54.9; P < 0.001). A smaller percentage of hospitals in Ontario than New York performed decompression (26.1% vs. 54.9%; P < 0.001) or fusion (15.2% vs. 56.7%; P < 0.001). Overall, utilization of spine surgery (decompression plus fusion) in Ontario was 6.6 procedures per-10,000 population per-year and in New York was 16.5 per-10,000 per-year (P < 0.001). Ontario-New York differences in utilization were smaller for emergent cases (2.0 per 10,000 in Ontario vs. 2.5 in New York; P < 0.001), but larger for elective cases (4.6 vs. 13.9; P < 0.001). The lower utilization in Ontario was particularly large among younger patients (age <60 years).

CONCLUSION

We found significantly lower utilization of spine surgery in Ontario than in New York. These differences should inform policy reforms in both jurisdictions.

LEVEL OF EVIDENCE

3.

Surgery for degenerative cervical spine disease in Finland, 1999-2015

Background

The incidence of surgery for degenerative cervical spine disease (DCSD) has risen by almost 150% in the USA in the last three decades and stabilized at slightly over 70 operations/100,000 people. There has been significant regional variation in the operation incidences. We aim to assess the diagnosis-based, age-adjusted trends in the operation incidences and the regional variation in Finland between 1999 and 2015.

Methods

Data from the Finnish Hospital Discharge Register (FHDR), the Cause of Death Register, and the registers of the Social Insurance Institution were combined to analyze all the primary operations for DCSD or rheumatoid atlanto-axial subluxation (rAAS). Combinations of the operative and the diagnosis codes were used to classify the patients into five diagnostic groups.

Results

A total of 19,701 primary operations were included. The age-adjusted operation incidence rose from 21.0 to 36.5/100,000 people between 1999 and 2013 and plateaued thereafter. The incidence of surgery for radiculopathy increased from 13.1 to 23.3 operations/100,000 people, and the incidence of surgery for DCM increased from 5.8 to 7.0 operations/100,000 people. The rise was especially pronounced in surgery for foraminal stenosis, which increased from 5.3 to 12.4 operations/100,000 people. Of the five diagnostic groups, only operations for rAAS declined. Operations increased especially in the 40- to 65-year-old age group. The overall operation incidences varied from 18.3 to 43.1 operations/100,000 people between the university hospitals.

Conclusions

The age-adjusted incidence of surgery for DCSD has risen in Finland by 76%, but the rise has plateaued. Surgery for radiculopathy, especially for foraminal stenosis, increased more steeply than surgery for degenerative medullopathy, with vast regional differences in the operation incidences.

Electronic supplementary material

The online version of this article (10.1007/s00701-019-03958-6) contains supplementary material, which is available to authorized users.

Future endeavors in ambulatory spine surgery

Due to the high societal and financial burden of spinal disorders, spine surgery is thought to be one of the most impactful targets for healthcare cost reduction. One avenue for cost-reduction that is increasingly being explored not just in spine surgery but across specialties is the performance of surgeries in ambulatory surgery centers (ASCs). Despite potential cost-savings, the utilization of ASCs for spine surgery remains largely limited to high-volume centers in the US, and predominantly for single- or two-level lumbar microdiscectomy and anterior cervical discectomy and fusion (ACDF) procedures. Factors most commonly cited for the lack of wider adoption include the risk of life-threatening complications, paucity of guidelines, and limited accessibility of these procedures to various patient populations. Thus, the future growth and adoption of ambulatory spine surgery depends on addressing these concerns by developing evidence-based guidelines for patient- and procedure selection, creating risk-stratification tools, devising appropriate discharge recommendations, and optimizing care protocols to ensure that safety, efficacy and outcomes are maintained. Other avenues that may allow for more widespread use of ASCs include the use of electronic health tools for post-operative monitoring after discharge from the ASC, increasing accessibility of ambulatory procedures to eligible populations, and identifying systemic inefficiencies and implementing process-improvement measures to optimize patient-selection, scheduling and peri-operative management. The success of ambulatory surgery ultimately depends not only on the surgical procedure, but also on its organization upstream and downstream. It provides an exciting and burgeoning avenue for innovation, cost-reduction and value-creation.

Using minimally invasive techniques adds to the value equation for select patients

Conditions of the spine are one of the most prevalent causes of global disability, and result in a considerable portion of total health expenditures. Surgical treatment of the spine has been demonstrated in multiple studies to be a cost-effective treatment option for many patients, especially with continuing improvements in surgical technique and instrumentation. Minimally invasive spine surgery (MISS), in particular, has evolved as a valuable option in treating certain patients. Numerous studies have analyzed minimally invasive techniques in regards to cost-effectiveness and other purported advantages. These advantages include conduciveness to outpatient settings, better perioperative and immediate post-operative benefits, and faster time to recovery. This article will describe the current literature on the advantages of MISS, specifically in regards to value and cost savings.

A Comparison of 30-Day Hospital Readmission and Complication Rates After Outpatient Versus Inpatient 1 and 2 Level Anterior Cervical Discectomy and Fusion Surgery: An Analysis of a Medicare Patient Sample

BACKGROUND

Same-day surgery has been demonstrated to be a safe and cost-effective alternative to traditional inpatient surgery. Several studies have demonstrated no differences in the postoperative complication profile or 30-day hospital readmission rates with outpatient versus inpatient anterior cervical discectomy and fusion (ACDF). However, none of these studies compared the outcomes in elderly patients (aged >65 years) undergoing ACDF. Whether the results from previous studies can be applied to this subgroup pf patients remains unknown. The aim of the present study was to compare the 30-day hospital readmission rates for Medicare patients (aged >65 years) undergoing outpatient versus inpatient ACDF.

METHODS

We performed a retrospective analysis of a Medicare database, including data from 17,421 patients. Of the 17,421 patients, 16,386 had undergone inpatient ACDF and 1035, outpatient ACDF. Age, sex, comorbidities, postoperative complications, readmission rates, and overall financial costs were compared between the 2 cohorts.

RESULTS

In a Medicare sample (aged >65 years), inpatient ACDF was associated with a greater incidence of postoperative complications compared with outpatient ACDF. Outpatient surgery was associated with significantly lower rates of postoperative complications (urinary tract infection, surgical site infection, deep vein thrombosis, pulmonary embolism, and myocardial infarction) and significantly lower treatment costs (P ≤ 0.001). All-cause 30-day hospital readmission rates were also greater for inpatients (10.1% vs. 4%; P = 0.17).

CONCLUSION

The results from the present study suggest that outpatient ACDF appears to be safe and effective with low complication and readmission rates in a Medicare patient sample.

Cardiac Complications Related to Spine Surgery: Timing, Risk Factors, and Clinical Effect

INTRODUCTION

Large cohort studies evaluating cardiac complications in patients undergoing spine surgery are lacking. The purpose of this study was to determine the incidence, timing, risk factors, and effect of cardiac complications in spine surgery by using a national database, the American College of Surgeons National Surgical Quality Improvement Program.

METHODS

Patients who underwent spine surgery in the 2005 to 2012 National Surgical Quality Improvement Program database were identified. The primary outcome was an occurrence of cardiac arrest or myocardial infarction during the operation or the 30-day postoperative period. Risk factors for development of cardiac complications were identified using multivariate regression. The postoperative length of stay, 30-day readmission, and mortality were compared between patients who did and did not experience a cardiac complication.

RESULTS

A total of 30,339 patients who underwent spine surgery were identified. The incidence of cardiac complications was 0.34% (95% confidence interval [CI], 0.27% to 0.40%). Of the cases in which a cardiac complication developed, 30% were diagnosed after discharge. Risk factors for the development of cardiac complications were greater age (most notably ≥80 years, relative risk [RR] = 5.53; 95% CI = 2.28 to 13.43; P < 0.001), insulin-dependent diabetes (RR = 2.58; 95% CI = 1.51 to 4.41; P = 0.002), preoperative anemia (RR = 2.46; 95% CI = 1.62 to 3.76; P < 0.001), and history of cardiac disorders and treatments (RR = 1.88; 95% CI = 1.16 to 3.07; P = 0.011). Development of a cardiac complication before discharge was associated with a greater length of stay (7.9 versus 2.6 days; P < 0.001), and a cardiac complication after discharge was associated with increased 30-day readmission (RR = 12.32; 95% CI = 8.17 to 18.59; P < 0.001). Development of a cardiac complication any time during the operation or 30-day postoperative period was associated with increased mortality (RR = 113.83; 95% CI = 58.72 to 220.68; P < 0.001).

DISCUSSION

Perioperative cardiac complications were diagnosed in approximately 1 in 300 patients undergoing spine surgery. High-risk patients should be medically optimized and closely monitored through the perioperative period.

LEVEL OF EVIDENCE

Level III.

Safety of 2-level Anterior Cervical Discectomy and Fusion (ACDF) Performed in an Ambulatory Surgery Setting With Same-day Discharge

STUDY DESIGN

This was a retrospective review of prospectively collected data.

OBJECTIVE

To evaluate differences in patient factors, procedural factors, outcomes and safety in 2-level anterior cervical discectomy and fusion (ACDF) performed in ambulatory surgery centers (ASCs) versus the hospital setting.

BACKGROUND

Emphasis on reducing health care costs has led to numerous surgeries across specialties being performed in ASCs. Because of short operative times and moderate postoperative pain, 1-level ACDF is one of the most common spine surgeries successfully performed in ASCs. Despite the success of single-level ACDF, concerns over postoperative complications, including respiratory compromise have curtailed the performance of 2-level ACDF in ASCs.

MATERIALS AND METHODS

Patient demographics, operative factors and outcomes [blood loss, operative time, length of stay, complications and patient-reported outcomes (PROs)] of patients undergoing 2-level ACDF in an ASC and a hospital were compared using the Fisher exact test for categorical and the Student t test for continuous variables.

RESULTS

Of the 83 patients included, 25 underwent 2-level ACDF in an ASC, and 58 in a hospital. Mean age for the ASC group was 51.7±7.6 and 53.2±7.9 years for the hospital group (P=0.44). Body mass index was lower in the ASC group, at 27.3 kg/m versus 30.4 in the hospital group (P=0.03). Likewise, the ASC group had a lower ASA grade, favoring ASA 1 and 2 (P<0.001). There were no differences in blood loss (P=0.72) or complication rates, (P=0.16) with urinary retention being most common, and only 1 patient in the hospital setting requiring reintubation. In addition, no patients in the ASC setting required hospitalization. There were no differences in preoperative, 6-week and 6-month PROs.

CONCLUSIONS

The results of our study suggest that 2-level ACDF can be performed safely in the ASC setting without increased risk of complications compared with the hospital setting in an appropriately selected patient. Specifically, body mass index, and ASA class should be taken into consideration. Importantly, the setting of the surgery does not impact early PROs.

LEVEL OF EVIDENCE

Level 3.

Predicting Surgical Complications in Adult Patients Undergoing Anterior Cervical Discectomy and Fusion Using Machine Learning

Objective

Machine learning algorithms excel at leveraging big data to identify complex patterns that can be used to aid in clinical decision-making. The objective of this study is to demonstrate the performance of machine learning models in predicting postoperative complications following anterior cervical discectomy and fusion (ACDF).

Methods

Artificial neural network (ANN), logistic regression (LR), support vector machine (SVM), and random forest decision tree (RF) models were trained on a multicenter data set of patients undergoing ACDF to predict surgical complications based on readily available patient data. Following training, these models were compared to the predictive capability of American Society of Anesthesiologists (ASA) physical status classification.

Results

A total of 20,879 patients were identified as having undergone ACDF. Following exclusion criteria, patients were divided into 14,615 patients for training and 6,264 for testing data sets. ANN and LR consistently outperformed ASA physical status classification in predicting every complication (p < 0.05). The ANN outperformed LR in predicting venous thromboembolism, wound complication, and mortality (p < 0.05). The SVM and RF models were no better than random chance at predicting any of the postoperative complications (p < 0.05).

Conclusion

ANN and LR algorithms outperform ASA physical status classification for predicting individual postoperative complications. Additionally, neural networks have greater sensitivity than LR when predicting mortality and wound complications. With the growing size of medical data, the training of machine learning on these large datasets promises to improve risk prognostication, with the ability of continuously learning making them excellent tools in complex clinical scenarios.

Does patient selection account for the perceived cost savings in outpatient spine surgery? A meta-analysis of current evidence and analysis from an administrative database

OBJECTIVEFrom 1994 to 2006 outpatient spinal surgery increased 5-fold. The perceived cost savings with outcomes comparable to or better than those achieved with inpatient admission for the same procedures are desirable in an era where health expenditures are scrutinized. The increase in outpatient spine surgery is also driven by the proliferation of ambulatory surgery centers. In this study, the authors hypothesized that the total savings in outpatient spine surgery is largely driven by patient selection and biases toward healthier patients.METHODSA meta-analysis assessed patient selection factors and outcomes associated with outpatient spine procedures. Pooled odds ratios and mean differences were calculated using a Bayesian random-effects model. The authors extended this analysis in a novel way by using the results of the meta-analysis to examine cost data from an administrative database of academically affiliated hospitals. A Bayesian approach with priors informed by the meta-analysis was used to compare costs for inpatient and outpatient performance of anterior cervical discectomy and fusion (ACDF) and lumbar laminectomy.RESULTSSixteen studies with a total of 370,195 patients met the inclusion criteria. Outpatient procedures were associated with younger patient age (mean difference [MD] -2.34, 95% credible interval [CrI] -4.39 to -0.34) and no diabetes diagnosis (odds ratio [OR] 0.78, 95% CrI 0.54-0.97). Outpatient procedures were associated with a lower likelihood of reoperation (OR 0.42, 95% CrI 0.16-0.80), 30-day readmission (OR 0.39, 95% CrI 0.16-0.74), and complications (OR 0.29, 95% CrI 0.15-0.50) and with lower overall costs (MD -$121,392.72, 95% CrI -$216,824.81 to -$23,632.92). Additional analysis of the national administrative data revealed more modest cost savings than those found in the meta-analysis for outpatient spine surgeries relative to inpatient spine surgeries. Estimated cost savings for both younger patients ($555 for those age 30-35 years [95% CrI -$733 to -$374]) and older patients ($7290 for those age 65-70 years [95% CrI -$7380 to -$7190]) were less than the overall cost savings found in the meta-analysis.CONCLUSIONSCompared to inpatient spine surgery, outpatient spine surgery was associated with better short-term outcomes and an initial reduction in direct costs. A selection bias for outpatient procedures toward younger, healthier patients may confound these results. The additional analysis of the national database suggests that cost savings in the outpatient setting may be less than previously reported and a result of outpatient procedures being offered more frequently to younger and healthier individuals.

A Comparison of Narcotic Consumption Between Hospital and Ambulatory-Based Surgery Centers Following Anterior Cervical Discectomy and Fusion

Background

Several studies have compared outcomes between hospital-based (HBCs) and ambulatory surgery centers (ASCs) following anterior cervical discectomy and fusion (ACDF). However, the association between narcotic consumption and pain in the early postoperative period has not been well characterized. As such, the purpose of this study is to compare pain, narcotic consumption, and length of stay (LOS) between HBC and ASC patients undergoing same-day-discharge following ACDF.

Methods

A surgical registry of patients who underwent a primary, 1- or 2-level ACDF during 2013-2015 was reviewed. Patients were stratified by operative location. Differences in demographics were assessed using independent-sample t tests and chi-square analysis. The presence of an association between operative location and outcomes was analyzed using Poisson regression with robust error variance or linear regression adjusted for preoperative characteristics.

Results

A total of 76 patients were identified, of which 42 and 34 underwent surgery at an HBC or ASC, respectively. The HBC cohort had greater total (P < .001) and hourly (P = .034) narcotic consumption and prolonged LOS (P < .001). Over 90% of ASC patients consumed less than or equal to the 30th percentile (32.0 mg) of oral morphine equivalents (OME), whereas over 57% of HBC patients consumed greater than 32.0 mg OME. The HBC cohort consumed greater average doses of fentanyl and oxycodone (P < .001 for each).

Conclusions

This study demonstrates that patients undergoing same-day surgery for primary 1- or 2-level ACDF received more narcotics at HBCs compared to at ASCs. The increased narcotic consumption at HBCs may have resulted in longer LOS; however, this did not impact long-term pain, complications, or clinical outcomes.

Clinical Relevance

Patients scheduled to be discharged on postoperative day 0 following ACDF at HBCs may be able to receive fewer narcotics and be discharged sooner without compromising pain control or increasing their risk for complications.

Safety and Efficiency of Cervical Disc Arthroplasty in Ambulatory Surgery Centers vs. Hospital Settings

Background

Outpatient surgery has been shown safe and effective for anterior cervical discectomy and fusion (ACDF), and more recently, for 1-level cervical disc arthroplasty (CDA). The purpose of this analysis is to compare the safety and efficiency of 1-level and 2-level CDA performed in an ambulatory surgery center (ASC) and in a hospital setting.

Methods

The study was a retrospective collection and analysis of data from consecutive CDA patients treated in ASCs compared to a historical control group of patients treated in hospital settings who were classified as outpatient (0 or 1-night stay) or inpatient (2 or more nights). Surgery time, blood loss, return to work, adverse events (AEs), and subsequent surgeries were compared.

Results

The sample consisted of 145 ASC patients, 348 hospital outpatients, and 65 hospital inpatients. A greater proportion of 2-level surgeries were performed in hospital than ASC. Surgery times were significantly shorter in ASCs than outpatient or inpatient 1-level (63.6 ± 21.6, 86.5 ± 35.8, and 116.7 ± 48.4 minutes, respectively) and 2-level (92.4 ± 37.3, 126.7 ± 43.8, and 140.3 ± 54.5 minutes, respectively) surgeries. Estimated blood loss was also significantly less in ASC than outpatient and inpatient 1-level (18.5 ± 30.6, 43.7 ± 35.9, and 85.7 ± 98.0 mL, respectively) and 2-level (21.1 ± 12.3, 67.8 ± 94.9, and 64.9 ± 66.1 mL). There were no hospital admissions and no subsequent surgeries among ASC patients. ASC patients had 1 AE (0.7%) and hospital patients had 10 AEs (2.4%). Working patients returned to work after a similar number of days off, but fewer ASC patients had returned to work by the end of the 90-day period.

Conclusions

Both 1- and 2-level CDA may be performed safely in an ASC. Surgeries in ASCs are of shorter duration and performed with less blood loss without increased AEs.

Comparison of Inpatient and Outpatient Preoperative Factors and Postoperative Outcomes in 2-Level Cervical Disc Arthroplasty

OBJECTIVE

The purpose of this study was to evaluate factors associated with inpatient admission following 2-level cervical disc arthroplasty (CDA). A secondary aim was to compare outcomes between those treated on an inpatient versus outpatient basis.

METHODS

Using data from the American College of Surgeons National Surgical Quality Improvement Program database, multivariate logistic regression analysis was used to assess the independent effect of each variable on inpatient or outpatient selection for surgery. Statistical significance was defined by p-values <0.05. The factors considered were age, sex, body mass index (BMI), smoking status, American Society of Anesthesiologists physical status classification, and comorbidities including hypertension, diabetes, history of dyspnea or chronic obstructive pulmonary disease, previous cardiac intervention or surgery, steroid usage, and history of bleeding. In addition, whether the operation was performed by an orthopedic or neurosurgical specialist was analyzed.

RESULTS

The number of 2-level CDA procedures increased from 6 cases reported in 2014 to 142 in 2016, although a statistically significant increase in the number of outpatient cases performed was not seen (p=0.2). The factors found to be significantly associated with inpatient status following surgery were BMI (p=0.019) and diabetes mellitus requiring insulin (p=0.043). There were no significant differences in complication and readmission rates between the inpatient and outpatient groups.

CONCLUSION

Patients undergoing inpatient 2-level CDA had significantly higher rates of obesity and diabetes requiring insulin than did patients undergoing the same procedure in the outpatient setting. With no difference in complication or readmission rates, 2-level CDA may be considered safe in the outpatient setting in appropriately selected patients.

Rates of Mortality in Cervical Spine Surgical Procedures and Factors Associated With Its Occurrence Over a 10-Year Period: A Study of 342 477 Patients on the Nationwide Inpatient Sample

Background

Risk of death is important in counseling patients and improving quality of care. Incidence of death in cervical surgery is not firmly established due to its rarity and limited sample sizes, particularly in the context of different surgeries, demographics, and risk factors. Particularly, different patient risk profiles may have varying degrees of risk in terms of surgeries, comorbidities, and demographics. This study aims to use a large patient cohort available on a national database to study the prevalence of death associated with cervical spine surgery.

Methods

This study was a retrospective review of the Nationwide Inpatient Sample (NIS) years 2003-2012. A total of 342 477 patients were identified by International Classification of Diseases, Ninth Revision, Clinical Modification codes undergoing spinal fusion or decompression for disc degeneration, stenosis, spondylosis, myelopathy, postlaminectomy syndrome, scoliosis, or neck pain associated with the cervical region. Patients with malignancy were excluded from analysis. Incidence of mortality was assessed by χ² tests across different patient demographics and comorbidities, procedures performed, and concurrent in-hospital complications. Binary logistic regression identified significant increases or decreases in risk of death while controlling for comorbidities, race, sex, and Mirza invasiveness. Significance was defined as P < .05 differences relative to overall cohort.

Results

The study analyzed 342 477 patients with an overall mortality rate of 0.32%. A total of 231 977 simple fusions (single approach and <3 levels) experienced a mortality rate of 0.256%; 49 594 complex fusions (combined approach or ≥3 levels) had a mortality rate of 0.534%; and 61 285 decompression-only procedures reported a 0.424% mortality rate, all P < .001 from overall rate. In reporting rates across different demographics, male patients experienced a significantly higher risk for mortality (odds ratio [OR], 2.16; 95% CI, 1.87-4.49), as did black patients (OR, 1.58; CI, 1.32-1.90) and patients over age 75 (OR, 7.55; 95% CI, 6.58-8.65), all P < .001. Patients with liver disease reported 6.40% mortality. Similarly, patients with congestive heart failure (3.91%), cerebrovascular disease (3.41%), and paraplegia (3.79%) experienced high mortality rates, all in cohorts of over 2000 patients, all P < .001. Concurrent in-hospital complications with the highest risk of mortality were shock (OR, 51.41; 95% CI, 24.08-109.76), pulmonary embolism (OR, 25.01; 95% CI, 14.70-42.56), and adult respiratory distress disorder (OR, 14.94; 95% CI, 12.75-17.52), all P < .001.

Conclusion

In 342 477 cervical spine surgery patients an overall mortality rate of 0.32% was reported. The rate was 3.91% in a cohort of 5933 patients with congestive heart failure and 3.79% in a cohort of 6947 patients with paraplegia. These findings are consistent with previous estimates and may help counsel patients and improve in-hospital safety.

Level of Evidence

3.

Comparing Health-Related Quality of Life Outcomes in Patients Undergoing Either Primary or Revision Anterior Cervical Discectomy and Fusion

STUDY DESIGN

A retrospective review of prospectively collected data.

OBJECTIVE

Compare health-related quality of life (HRQOL) outcome metrics in patients undergoing primary and revision anterior cervical discectomy and fusion (ACDF).

SUMMARY OF BACKGROUND DATA

ACDF is associated with significant improvements in HRQOL outcome metrics. However, 2.9% of patients per year will develop symptomatic adjacent segment disease and there is a paucity of literature on HRQOL outcomes after revision ACDF.

METHODS

Patients were identified who underwent either a primary or revision ACDF, and who had both preoperative and a minimum of 1-year postoperative HRQOL outcome data. Pre- and postoperative Short Form 12 Physical Component Score (SF12 PCS), Short Form 12 Mental Component Score (SF12 MCS) Visual Analog Scale for neck pain (VAS-Neck), VAS-Arm, and Neck Disability Index (NDI) scores were compared.

RESULTS

A total of 360 patients (299 primary, 61 revision) were identified. Significant improvement in SF12 PCS, NDI, VAS-Neck, and VAS-Arm was seen in both groups; however, only a significant improvement in SF12 MCS was seen in the primary group. When comparing the results of a primary versus a revision surgery, the SF12 PCS score was the only outcome with a significantly different net improvement in the primary group (7.23 ± 9.72) compared to the revision group (2.9 ± 11.07; P = 0.006) despite similar baseline SF12 PCS scores. The improvement in each of the other reported HRQOL outcomes did not significantly vary between surgical groups.

CONCLUSION

A revision ACDF for cervical radiculopathy or myelopathy leads to a significant improvement in the HRQOL outcome, and with the exception of the SF12 PCS, these results are similar to those of patients undergoing a primary ACDF.

LEVEL OF EVIDENCE

2.

Radiation exposure to the surgeon during minimally invasive spine procedures is directly estimated by patient dose

PURPOSE

Radiation exposure is a necessary component of minimally invasive spine procedures to augment limited visualization of anatomy. The surgeon's exposure to ionizing radiation is not easily recognizable without a digital dosimeter-something few surgeons have access to. The aim of this study was to identify an easy alternative method that uses the available radiation dose data from the C-arm to accurately predict physician exposure.

METHODS

The senior surgeon wore a digital dosimeter during all minimally invasive spine fusion procedures performed over a 12-month period. Patient demographics, procedure information, and radiation exposure throughout the procedure were recorded.

RESULTS

Fifty-five minimally invasive spine fusions utilizing 330 percutaneous screws were included. Average radiation dose was 0.46 Rad/screw to the patient. Average radiation exposure to the surgeon was 1.06 ± 0.71 μSv/screw, with a strong positive correlation (r = 0.77) to patient dose. The coefficient of determination (r²) was 0.5928, meaning almost two-thirds of the variability in radiation exposure to the surgeon is explained by radiation exposure to the patient.

CONCLUSIONS

Intra-operative radiation exposure to the patient, which is easily identifiable as a continuously updated fluoroscopic monitor, is a reliable predictor of radiation exposure to the surgeon during percutaneous screw placement in minimally invasive spinal fusion surgery and therefore can provide an estimate of exposure without the use of a dosimeter. With this, a surgeon can better understand the magnitude of their exposure on a case-by-case basis rather than on a quarterly basis, or more likely, not at all. These slides can be retrieved under Electronic Supplementary Material.

Are Patients Undergoing an Anterior Cervical Discectomy and Fusion Treated Differently at a Physician-owned Hospital?

STUDY DESIGN

Retrospective case-control study.

BACKGROUND

Physician-owned specialty hospitals focus on taking care of patients with a select group of conditions. In some instances, they may also create a potential conflict of interest for the surgeon. The effect this has on the surgical algorithm for patients with degenerative cervical spine conditions has not been determined.

METHODS

A retrospective review of all patients who underwent a 1- or 2-level anterior cervical discectomy and fusion between October 2009 and December 2014 at either a physician-owned specialty hospital or an independently owned community hospital were identified. Demographic information, the time course for treatment and the nonoperative treatment regimen were evaluated.

RESULTS

In total, 115 patients undergoing surgery at a physician-owned specialty hospital and 149 patients undergoing surgery at an independent community hospital were identified. Demographic data between the groups including the presence of 12 medical comorbidities and insurance status was similar between the groups. The only difference that was identified was that patients at the surgeon-owned hospital were marginally younger than patients who had surgery at the independent hospital (49.7 vs. 50.0, P=0.048). No difference in the median number of months from the onset of symptoms to surgery (6.51 vs. 7.53 mo, respectively; P=0.55), from the onset of symptoms to the preoperative visit (6.02 vs. 6.02, P=0.64), or from the initial surgical consultation to surgery (0.99 vs. 1.02, P=0.31) was identified. No difference in the number of patients who underwent formal physical therapy (72.2% vs. 67.1%, P=0.42) or who had a cervical steroid injection (55.6% vs. 50.3%, P=0.25%) was identified between patients who had surgery at a physician-owned or independent hospital; however, patients who underwent surgery at the physician-owned hospital were more likely to have taken oral anti-inflammatories (93.0% vs. 83.9%, P=0.04).

CONCLUSIONS

When comparing hospitals with similar resources, surgeons do not preferentially select younger, healthier patients with higher paying insurance to be treated at the physician-owned hospital. Furthermore, both the time from the onset of symptoms to surgery and the nonoperative treatment regimen were similar between patients treated at the 2 facilities.

Outpatient spine surgery: defining the outcomes, value, and barriers to implementation

Spine surgery is a key target for cost reduction within the United States health care system. One possible strategy involves the transition of inpatient surgeries to the ambulatory setting. Lumbar laminectomy with or without discectomy, lumbar fusion, anterior cervical discectomy and fusion, and cervical disc arthroplasty all represent promising candidates for outpatient surgeries in select populations. In this focused review, the authors clarify the different definitions used in studies describing outpatient spine surgery. They also discuss the body of evidence supporting each of these procedures and summarize the proposed cost savings. Finally, they examine several patient- and surgeon-specific considerations to highlight the barriers in translating outpatient spine surgery into actual practice.