Level Posterior Lumbar Fusions Research Articles

Robotic Versus Navigation Assisted Posterior Lumbar Fusion: A National Database Study.

Retrospective cohort study. Compare perioperative adverse events and reoperations between navigation-assisted and robotic-assisted posterior lumbar fusion. Navigation has become increasingly utilized for posterior lumbar fusion (PLF). More recently, robotic assistance systems have been gaining traction. However, the incremental advantage of these systems has been unclear in the literature. Patients undergoing one to three level PLF (with or without anterior or posterior interbody fusion) were identified from the 2015-2022 M161Ortho PearlDiver Database using CPT codes. Navigation assistance was identified based on CPT coding and robotic assistance was based on ICD-10 procedural coding. Navigation-assisted cases were matched 4:1 to robotic assisted patients based on age, sex, Elixhauser Comorbidity Index, number of levels fuse, and concomitant anterior fusion. Incidence of 90-day adverse outcomes were assessed and compared with multivariable logistical regression. Bonferroni correction was applied for multiple testing. Rate of reoperation was assessed using a Kaplan-Meier survival analysis. From 2015 to 2022, there has been a significant increase in both navigation and robotic assisted lumbar fusions, with navigation-assisted surgery being significantly more common. After matching, there were 2,401 navigation-assisted cases and 651 robotic-assisted cases. On multivariate analysis, there no significant differences in 90-day any, severe, or minor adverse events. There was a significant increase odd of readmissions in the robotic cohort (OR: 1.77, P<0.001). There were no differences in three-year reoperation rates between the navigation-assisted and robotic-assisted cohorts (95.8% versus 94.0%, P=0.30). As spinal navigation has been gaining popularity and robotic assistance is starting to be further utilized, the incremental advantage of different techniques may be questioned. While further study and technique evolution are ongoing, the current study was not able to demonstrate 90-day or 3-year incremental advantages for robotics relative to navigation based on the metrics evaluated.

Physical Therapy Utilization Following Single Level Posterior Lumbar Fusion.

Retrospective cohort study. Characterize physical therapy (PT) utilization following single-level posterior lumbar fusion (PLF). PLF is a common procedure that is increasing in frequency. Following such surgeries, PT may be considered to facilitate mobilization and return to activities. However, the usage of such therapy has not been well-characterized in the literature. Patients undergoing single-level PLF were identified from the 2010-2021 PearlDiver administrative database. These patients were stratified based on usage of therapy, home versus outpatient therapy, and timing of therapy within the year following surgery. To determine predictors of therapy, patient characteristics were determined and multivariable regressions were performed. A total of 213,240 patients undergoing single-level PLF were identified, of which therapy was done in the year following surgery for 63,231 (29.0%, of which home therapy accounted for 16.5% of therapy visits). Of those who utilized PT, the average number of visits was 10.6±10.6. Home therapy peaked within the first month following surgery and outpatient therapy peaked at month two. Factors associated with any PT following PLF in decreasing odds ratio (OR) were: having commercial insurance (OR: 1.68), being from the Northeast (OR:1.41), age (OR: 1.13 for 70+ of age) female sex (OR: 1.09), and ECI (OR: 1.04 per point) (P<0.001 for all). Of those who received therapy, factors associated with home PT utilization were: being from the Northeast (OR: 2.55), age (OR: 1.91 for 70+ of age), Medicaid insurance (OR: 1.48), female sex (OR: 1.39), and interbody fusion (OR:1.07) (P<0.001 for all). Following single-level PLF, the minority of patients received home or outpatient PT. Of those that did, there was significant variation in the number of visits, with nonmedical factors such as insurance plan and geographic region being strongly associated suggesting room for more consistent practice patterns. III.

Weight loss makes the difference: perioperative outcomes following posterior lumbar fusion in patients with and without weight loss following bariatric surgery

Morbid obesity (MO) has been associated with increased risk of adverse events following procedures such as posterior lumbar fusion (PLF). While preemptive bariatric surgery (BS) has been considered for those with MO (body mass index [BMI] ≥35 kg/m2), not all undergoing such intervention have significant weight loss, and the impact of BS has been shown to correlate with weight loss after different related procedures. To examine outcomes following isolated single level PLF among patients with history of BS who subsequently did and did not transition out of the morbidly obese category. Retrospective case-control study. The PearlDiver 2010-Q1 2020 MSpine database was used to identify adult patients undergoing elective isolated PLF. Patients were excluded if they had a history of infection, neoplasm, or trauma in the 90-days prior to their PLF and if they were not active in the database for at least 90 days following their surgery. Three sub-cohorts were defined: 1) MO controls without a history of BS (-BS+MO), 2) patients with prior BS procedure who remained MO (+BS+MO), and 3) patients with prior BS who were no longer MO at the time of PLF (+BS-MO). Matched 1:1:1 populations were created for these three sub-cohorts based on age, sex and Elixhauser Comorbidity Index (ECI). Ninety-day adverse events and readmission rates were assessed and compared between the three sub-cohorts (-BS+MO, +BS+MO, +BS-MO). Univariable analyses and multivariable logistic regression were performed on the matched population to compare 90-day adverse events and readmission rates controlling for age, sex, and ECI. The current study identified PLF patients who were MO at the time of surgery but did not have a history of BS (-BS+MO, n=34,236), those who had BS and remained MO (+BS+MO, n=564), and those who had MS and were no longer MO (+BS-MO, n=209 which was only 27% of those who had BS). On multivariable analysis of the matched populations, those that had BS but remained MO (+BS+MO) were not at reduced odds of 90-day adverse events. However, those that had BS and were no longer MO (+BS-MO) were at reduced odds of 90-day any, severe, and minor adverse events (OR 0.41, 0.51, and 0.37, respectively with p<0.05 for all). Only 27% of those with a history of BS prior to PLF transitioned out of the MO category. Compared to those who were morbidly obese without BS, those who had BS were only at reduced risk of 90-day adverse events if they actually lost weight sufficient to drop out of morbidly obesity. These findings should be taken into account when counseling patients and interpreting prior studies.

Modifiable Patient Factors Demonstrate No Increased Risk for 30-Day Complication Rate for Elective 1-2 Level Posterior Lumbar Fusion Surgery: A Comparison Between a National Database and Local Registry.

While national databases provide large datasets that can be used to understand trends over time, their correlation with prospectively collected data from local registries has not been established. The purpose of the study was to compare differences in patient demographics and adverse events for patients undergoing elective posterior spinal fusion (PSF) between a national database and institutional registry. A retrospective chart review was performed. A total of 14,618 patients (13,678 patients from the National Surgical Quality Improvement Program [NSQIP] database and 940 patients from the institutional registry) who underwent elective 1- to 2-level PSF were included in the study. Preoperative patient demographics and comorbidities of each cohort were compared. In addition, postoperative 30-day complications and readmission were collected. A multivariate analysis was performed to examine for differences in risk factors for 30-day adverse events between the 2 cohorts. A total of 13,678 patients from the NSQIP database and 940 patients from the institutional cohort were included for analysis. Mean age was similar between patient cohorts (60.8 ± 13.1NSQIP vs 58.8 ± 12.9registry), with NSQIP having significantly more patients over the age of 65 (41.4% vs 33.2%, P < 0.001). Overall complication rate was similar between NSQIP (6.8%) and the institutional registry (8.4%). Both found age and female sex to be significant predictors of 30-day adverse events, while obesity, hypertension, and smoking were only found to be predictive in the NSQIP database. Age and female sex were found to be independent risk factors for 30-day adverse events between both cohorts, while only NSQIP found modifiable comorbidities to be significant predictors. Although large databases allow for trends in quality over time, subtleties in practice variation and data collection methods at the individual institution level need to be considered when generalizing findings, especially as it pertains to modifiable factors. Quality metrics and risk factors for patient outcomes are often derived from national databases. This study highlights the differences between study results when outcomes are derived from an institutional registry compared to a national database.

P111. Undergoing elective posterior lumbar fusions at “US News & World Report” ranked hospitals versus non-ranked hospitals: do rankings even matter?

BACKGROUND CONTEXT The US News and World Report (USNWR) hospital rankings remain the most publicly referenced system for identifying top hospitals for each specialty. However, due to recent methodological concerns on whether rankings are reflective of objective data, the rankings have been shrouded in controversy in the medical world. PURPOSE The current study aims to evaluate whether there are any differences in outcomes and costs for patients undergoing elective 1-to-3 level posterior lumbar fusions at ranked and non-ranked hospitals. STUDY DESIGN/SETTING Retrospective analysis of the 2010-2014 Medicare 100% Standard Analytical Files (SAF100) database. PATIENT SAMPLE The 2010-2014 USNWR hospital rankings were used to identify ranked hospitals in “Neurosurgery” and “Orthopedics.” Since surgeons from both specialties routinely perform elective lumbar fusions, top ranked hospitals from both specialties were included in the study. The 2010-2014 100% Medicare Standard Analytical Files (SAF100) were used to identify patients undergoing elective 1-to-3 level posterior lumbar fusions for degenerative spinal pathology. OUTCOME MEASURES Ninety-day outcomes and costs. METHODS The study cohort was divided into two groups, based on whether patients received surgery at a ranked hospital vs a non-ranked hospital. Multi-variate logistic and linear regression analyses were used to assess for differences in 90-day outcomes and costs between ranked and non-ranked hospitals, while controlling for potential co-variates/confounders. RESULTS A total of 149,863 patients undergoing elective 1-to-3 level posterior lumbar fusions were included in the study, out of which 15,722 (10.5%) underwent surgery in one of the 100 ranked hospitals across the study time period. Ranked hospitals were more likely to have a higher annual case volume, greater bed size, be teaching hospitals and be located in a low socioeconomic area. After adjusting for age, gender, region, comorbidity burden and hospital-level characteristics, there were no significant differences between ranked vs non-ranked hospitals with regards to wound complications (4.6% vs 4.3%; p=0.299), cardiac complications (8.3% vs 7.8%; p=0.077), thromboembolic complications (3.0% vs 2.3%; p=0.208), pneumonia (2.0% vs 2.3%; p=0.482), urinary tract infections (10.6% vs 9.7%; p=0.109), renal complications (4.2% vs 4.0%; p=0.255), revision surgery (0.5% vs 0.4%; p=0.886) and all-cause readmissions (10.0% vs 10.0%; p=0.843). Patients undergoing surgery at ranked hospitals vs non-ranked hospitals had slightly lower odds of experiencing septic complications (1.0% vs 1.3%; OR 0.78 [95% CI 0.64-0.94]; p=0.010), however these findings were largely not clinically significant. Elective posterior lumbar fusions at ranked hospitals, however, had significantly higher risk-adjusted 90-day charges (+ 11,938; p CONCLUSIONS Elective posterior lumbar fusions at ranked hospitals have similar outcomes as compared to non-ranked hospitals, even though ranked hospitals have higher costs of care over the 90-day episode of care. The findings of the study support the need for a better clinical approach towards defining hospital rankings. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

P110. Hospital network participation and outcomes following elective posterior lumbar fusions: are mergers warranted?

BACKGROUND CONTEXT Due to financial pressures associated with health care reforms, an increasing number of hospitals are now integrating/merging into networks or systems. However, it remains unclear as to how these mergers or network participations impact quality of care and/or costs. PURPOSE The current study aims to evaluate the impact of hospital network participation on 90-day complications, charges and costs following elective posterior lumbar fusions (PLFs). STUDY DESIGN/SETTING Retrospective review of a 100% national sample of Medicare claims from 2010-2014 (SAF100). PATIENT SAMPLE The 2010-2014 100% Medicare Standard Analytical Files (SAF100) was used to identify patients undergoing elective 1-to-3 level posterior lumbar fusions for degenerative lumbar pathology. The Dartmouth Atlas for Healthcare hospital-level data, which uses a combination of American Hospital Association and additional source data, was used to identify hospitals that were part of a network/system between 2010 and 2014. The study sample was divided into two cohorts (Network Hospitals and Non-Network Hospitals) for analyses. OUTCOME MEASURES Ninety-day complications, charges and costs. METHODS Multi-variate logistic regression models were used to compare differences in 90-day complications between network and non-network hospitals, while controlling for baseline demographics (age, gender, region, year of surgery, median household income, co-morbidity burden) and hospital-level characteristics (case volume, teaching status, urban/rural location and hospital ownership). Generalized linear regression modeling was used to assess for differences in 90-day charges and costs. RESULTS A total of 145,141 patients undergoing surgery in 2,186 hospitals were included in the study – out of which 107,919 (74.4%) underwent surgery in a network hospital (N=1,526). Network hospitals were likely to cater to patients from the South or West, and those having a median household income less than the 5th quintile. Network hospitals were also more likely to have a higher annual case volume of elective 1-to-3 PLFs, greater number of beds, be located in an urban location, and have a voluntary/non-profit or proprietary/profit ownership model. Multi-variate analyses showed that even though patients undergoing surgery at network hospitals (vs non-network hospitals) had a slightly increased odds of 90-day cardiac complications (7.9% vs 7.4%, OR 1.07 [95% CI 1.02-1.12]; p=0.010), thromboembolic complications (2.4% vs 2.2%, OR 1.12 [95% CI 1.01-1.20]; p=0.025) and emergency department visits (16.4% vs 16.0%, OR 1.06 [95% CI 1.02-1.09]; p=0.002), the differences were not clinically important/significant. Despite a slight, but clinically insignificant, decrease in risk-adjusted 90-day reimbursements (-$272), the risk-adjusted 90-day charges were actually significantly higher (+ $9,959; p CONCLUSIONS Even though hospitals that are part of a network/system do not appear to have significantly different complication rates following elective PLFs, they do have significantly higher risk-adjusted charges, as compared to non-network hospitals. Further research is required to understand market-level changes induced by hospital mergers into networks. Additionally, as the federal government increasingly pushes hospitals towards implementing value, a broader understanding of hospital network participation on outcomes following other orthopedic surgical procedures is required to best ensure that policies laid down in the upcoming years are geared towards ensuring quality health care is made equitable and accessible to all. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Hospital network participation and outcomes following elective posterior lumbar fusions – are mergers effective?

Background contextDue to financial pressures associated with healthcare reforms, an increasing number of hospitals are now merging (or consolidating) into networks (or systems). However, it remains unclear how these mergers or network participations affect quality of care and/or costs. PurposeThe current study aims to evaluate the impact of hospital network participation on 90-day complications, charges, and costs following elective posterior lumbar fusions (PLFs). Study designRetrospective review of a 100% national sample of Medicare claims from 2010 to 2014 (SAF100). Study sampleAll Medicare-eligible patients undergoing elective 1-to-3 level PLFs for degenerative lumbar pathology from 2010 to 2014. Outcome measuresNinety-day complications, charges, and costs. MethodsThe 2010 to 2014 100% Medicare Standard Analytical Files (SAF100) was used to identify patients undergoing elective 1- to 3-level PLFs for degenerative lumbar pathology. The Dartmouth Atlas for Healthcare hospital-level data, which uses a combination of American Hospital Association and additional source data, was used to identify hospitals that were part of a network (or system) between 2010 and 2014. The study sample was divided into 2 cohorts (network hospitals and non-network hospitals) for analyses. Multivariate logistic regression models were used to compare differences in 90-day complications between network and non-network hospitals, while controlling for baseline demographics (age, gender, region, year of surgery, median household income, co-morbidity burden) and hospital-level characteristics (case volume, teaching status, urban/rural location, and hospital ownership). Generalized linear regression modeling was used to assess for differences in 90-day charges and costs. ResultsA total of 145,141 patients undergoing surgery in 2,186 hospitals were included in the study, out of which 107,919 (74.4%) underwent surgery in a network hospital (N=1,526). Network hospitals were more prevalent in the South or West regions of the United States. Patients in network hospitals had a median household income less than the 5th quintile. Network hospitals were also more likely to have a higher annual case volume of elective 1- to 3-level PLFs, greater number of beds, be located in an urban location, and have a voluntary/nonprofit or proprietary/profit ownership model. Multivariate analyses showed that even though patients undergoing surgery at network hospitals (vs non-network hospitals) had a slightly increased odds of 90-day cardiac complications (7.9% vs 7.4%, odds ratio [OR] 1.07 [95% confidence interval {CI} 1.02–1.12]; p=.010), thromboembolic complications (2.4% vs 2.2%, OR 1.12 [95% CI 1.01–1.20]; p=.025) and emergency department visits (16.4% vs 16.0%, OR 1.06 [95% CI 1.02–1.09]; p=.002), the differences would not be considered clinically significant. Despite a slight decrease in risk-adjusted 90-day reimbursements (−$272), the risk-adjusted 90-day charges were actually significantly higher (+$9,959; p<.001) at network hospitals. ConclusionsEven though hospitals that are part of a network do not appear to have significantly different complication rates following elective PLFs, they do have significantly higher risk-adjusted charges as compared to non-network hospitals. Further research is required to understand market-level changes induced by hospital mergers into networks.

63. Orthopedic vs neurosurgery: understanding 90-day complications and costs in patients undergoing elective 1- to 2-level posterior lumbar fusions by different specialties

BACKGROUND CONTEXT Spine surgery is routinely performed by either orthopedic or neurological spine surgeons. Controversy still exists as to whether a provider's specialty (orthopedic vs neurosurgery) influences outcomes. PURPOSE With present evidence limited to inpatient-only and 30-day outcomes, the current study aims to understand differences in 90-day complication rates and health care resource utilization/costs between orthopedic and neurosurgical spine surgeons performing elective 1- to 2-level posterior lumbar fusions. STUDY DESIGN/SETTING Retrospective review of insurance claims from the Humana Commercial Database. PATIENT SAMPLE The 2007-2015Q2 Humana Commercial Database was queried using Current Procedural Terminology codes (22612, 22614, 22630, 22632, 22633 and 22634) to identify patients undergoing 1-to-2 level posterior lumbar fusions with active enrollment up to 90-days post-procedure. Patients undergoing fusion due to trauma, deformity and/or malignancy were excluded to capture a relevant study population of patients with degenerative lumbar pathology. OUTCOME MEASURES The 90-day complications included wound, pulmonary, cardiac, thromboembolic, sepsis, pneumonia, urinary tract infections, renal, dural tears and mechanical complications. Additional outcomes included emergency department (ED) visits, revision surgeries and readmissions within 90 days. The surgical and 90-day resource utilization costs for the two groups were compared, by studying average reimbursements for acute-care (index hospitalization, surgeon and anesthesia) and postacute care categories (office visits, nursing care, home health services, physical therapy, emergency department visits and readmissions). METHODS All 90-day complications and costs were compared using multivariable logistic and linear regression techniques while controlling for baseline differences in age, gender, race, region, Elixhauser Co-morbidity Index (ECI) and type of plan/benefit. RESULTS A total of 10,509 patients (5,523 = orthopedic, 4,986 = neurosurgery) underwent an elective 1- to 2- level posterior lumbar fusion during the time period. With the exception of a significantly lower odds of wound complications (OR 0.81) and a higher odds of dural tears (OR 1.29) in elective posterior lumbar fusions performed by orthopedic surgeons, no statistically strong differences were seen in 90-day complication rates between the two groups. Total 90-day costs were also similar between orthopedic and neurosurgeons, with the only exception being that surgeon reimbursement was lower for orthopedic surgery vs neurosurgery ($1,202 vs $1,372; p CONCLUSIONS A provider's specialty does not largely influence 90-day surgical safety outcomes and costs. The results of the study promote the formation and acceptance of dual training pathways for entry into the realm of spine surgery. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

93. Certificate-of-Need state laws and elective posterior lumbar fusions: a Medicare trends, costs and outcomes analysis

BACKGROUND CONTEXT Certificate-of-Need (CON) state laws have been a major mandate of health policies aimed at forming centralized health planning as a key-core of the US health care system. Though the federal CON mandate was repealed in 1986, several states still continue to use it as a means of limiting health care resource utilization while attempting to provide quality care in high-volume facilities. PURPOSE The current study aimed to utilized a national Medicare claims dataset to assess whether elective posterior lumbar fusions (PLFs) performed in CON vs No CON states had lower utilization rates, lower costs, and better quality of care. STUDY DESIGN/SETTING Retrospective review of administrative claims from the 100% Medicare Standard Analytical Files (SAF100). PATIENT SAMPLE The 2005-2014 100% Medicare Standard Analytical File (SAF100) was queried to identify patients undergoing elective 1-to-3 level PLF. OUTCOME MEASURES Trends in utilization during the study period (2005-2014), average 90-day costs/reimbursements, 90-day complications and 90-day readmissions. METHODS Patients were categorized into ‘CON’ and ‘No CON’ based on existing state laws where they received the procedure. For each group (CON vs No CON), differences in per-capita utilization, 90-day reimbursements and proportion of high-volume facilities (>150 procedures/year) vs low-volume facilities (≤50 procedures/year) have been reported. Multivariate analyses were used analyze 90-day complication/readmission rates between the two groups. RESULTS A total of 188,687 patients underwent an elective 1- to 3-level PLF in a CON state and 167,642 patients received the procedure in a No CON state from 2005 to 2014. The average per capita utilization of PLFs was lower in CON states as compared to No CON states (14.5 vs 15.4 per 10,000 population; p CONCLUSIONS While the presence of CON laws was associated with lower utilization of elective 1-to-3 level PLFs, and a greater presence of high-volume facilities, the mandate's effect on enhancing quality-of-care, by reduction of 90-day readmissions and 90-day complications is minimally significant. Future research, involving other surgical subspecialties, is needed before health policy makers may consider the removal or alteration of these laws. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

303. Intravenous ketorolac substantially reduces opioid use following lumbar spinal fusion: early results of a randomized, double-blinded, placebo controlled trial

BACKGROUND CONTEXT Lumbar spine fusions are rated amongst the most painful surgical procedures. Adequately controlling post-operative pain while minimizing opioid use is an important public health objective PURPOSE The purpose of this study was to examine the effect of intravenous ketorolac (IV-K) on hospital opioid use compared to IV placebo (IV-P) and IV Acetaminophen (IV-A). STUDY DESIGN/SETTING Prospective, randomized, double-blind trial. PATIENT SAMPLE Patients aged 18-75 undergoing 1-2 level posterior lumbar fusion without history of long-term opioid use. Smokers and those with contraindications to IV-A or IV-K were excluded OUTCOME MEASURES The primary outcome was in-hospital opioid use up to post-operative day 3 (POD3). The secondary outcomes were opioid related adverse events (ORAE) and length of stay (LOS). METHODS Patients (Pts) were randomized to receive IV-K, IV-P or IV-A. IV-K pts received 15mg (age > 65) or 30mg (age RESULTS A total of 115 patients met the inclusion criteria (39 IV-K, 39 IV-A, 37 IV-P). There was no difference between patients with regards to demographic or surgical variables. The IV-K group had substantially lower opioid use at 72h (181±156mg) compared to IV-A (268± 176mg) and IV-P (315±183mg) (p=0.003). IV-K was superior to IV-A (p=0.030) and IV-P (0.001). IV-A was not superior to IV-P (p=0.234). Similar trends were observed for opioid use per hour (IV-K: 3.0±2.4mg/hr; IV-A: 4.1±2.3mg/hr; IV-P: 4.7±2.5mg/hr, p=0.009). IV-K pts reported improved pain control on POD1 (p=0.050). IV-K pts trended toward shorter LOS (IV-K: 75±44hr; IV-A: 93±60hr; IV-P:88±35hr, p=0.231). There were no differences in ORAE, drain output, hematocrit levels, serum creatinine and transfusion rates. CONCLUSIONS IV-K results in a substantial reduction in opioid use (>40% vs IV-P, >30% vs IV-A) and improved pain control on POD1. There is a trend toward decreased LOS; there appears to be no increase in in-hospital complications. Longer term follow-up is planned to assess the impact of IV-K on pseudarthrosis. FDA DEVICE/DRUG STATUS Unavailable from authors at time of publication.

128. Posterior lumbar fusions (PLFs) at physician-owned hospitals: reconsidering the restrictions of the Affordable Care Act (ACA)

BACKGROUND CONTEXT Due to perceptions and concerns about unnecessary high resource utilization/costs and low quality of care provided in physician owned hospitals, the Affordable Care Act (ACA) of 2010 imposed restrictions on existing physician-owned hospitals from expanding. PURPOSE The current study aimed to assess differences in 90-day costs and outcomes between patients undergoing elective 1-to-3 level posterior lumbar fusions (PLFs) at physician-owned hospitals vs non-physician–owned hospitals. STUDY DESIGN/SETTING Retrospective review of 2007-2014 100% Medicare Standard Analytical Files (SAF100) database. PATIENT SAMPLE The 2007-2014 Medicare 100% Standard Analytical Files (SAF100) database was queried using International Classification of Diseases, 9th Edition (ICD-9) procedure code for patients undergoing elective 1- to 3-level posterior lumbar fusions (81.07, 81.08 and 81.62). The Medicare Hospital Compare database was used to identify provider codes for physician-owned hospitals and were cross-referenced to identify records of patients receiving elective posterior lumbar fusions at these hospitals from the SAF100 database. OUTCOME MEASURES Ninety-day complications, readmissions, charges and costs. METHODS Multivariate logistic and linear regression analyses were used to assess significant differences in 90-day complications, readmissions, charges and costs between the two groups. RESULTS A total of 6,679 (2.9%) patients received an elective posterior lumbar fusion at a physician-owned hospital (N=39; 2.2%) whereas 225,090 (97.1%) received surgery at non-physician–owned hospital (N=1,774; 97.8%). After controlling for age, gender, region, hospital factors (socioeconomic status area, urban vs rural location and volume) and ECI, undergoing surgery at physician-owned hospital was associated with lower odds of thromboembolic complications (OR 0.66 [95% CI 0.53-0.82]; p CONCLUSIONS Our results suggest that patients undergoing elective 1-to-3 level PLFs at physician-owned hospitals have fewer charges and costs over the 90-day episode of care, while having lower odds of experiencing urinary tract infections, thromboembolic complications and renal complications within 90-days of the surgery. The findings call into the need for revaluation/reconsideration of the ACAs restriction on the expansion of these physician-owned hospitals. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Orthopedic versus Neurosurgery–Understanding 90-Day Complications and Costs in Patients Undergoing Elective 1-Level to 2-Level Posterior Lumbar Fusions by Different Specialties

Lumbar fusions are routinely performed by either orthopedic or neurologic spine surgeons. Controversy still exists as to whether a provider's specialty (orthopedic vs. neurosurgery) influences outcomes. The 2007-2015Q2 Humana Commercial Database was queried using Current Procedural Terminology codes (22612, 22614, 22630, 22632, 22633 and 22634) to identify patients undergoing elective 1-to-2 level posterior lumbar fusions (PLFs) with active enrollment up to 90 days after procedure. Ninety-day complication rates were calculated for the 2 specialties. The surgical and 90-day resource utilization costs for the 2 groups were compared, by studying average reimbursements for acute-care and post-acute-care categories. Ninety-day complications and costs were compared using multivariable logistic and linear regression analyses. A total of 10,509 patients (5523 orthopedic and 4986 neurosurgery) underwent an elective 1-to-2 level PLF during the period. With the exception of a significantly lower odds of wound complications (odds ratio, 0.81) and a higher odds of dural tears (odds ratio, 1.29) in elective PLFs performed by orthopedic surgeons, no statistically strong differences were seen in 90-day complication rates between the 2 groups. Total 90-day costs were also similar between orthopedic surgeons and neurosurgeons, with the only exception being that surgeon reimbursement was lower for orthopedic surgery versus neurosurgery ($1202 vs. $1372; P< 0.001). It seems that a provider's specialty does not largely influence 90-day surgical outcomes and costs after elective PLFs. The results of the study promote the formation and acceptance of dual training pathways for entry into spine surgery.

Wednesday, September 26, 2018 10:35 AM – 12:00 PM Understanding Lumbar Stenosis/Spondylolisthesis: 12. A preoperative score for predicting 30-day readmission after elective 1- or 2-level posterior lumbar fusion

BACKGROUND CONTEXT Posterior lumbar fusion is one of the most commonly performed procedures in the United States. Readmission rates are an important metric of quality of care and directly tied to reimbursement. Identification of factors that influence readmission rates is valuable for preoperative optimization and for appropriate risk stratification of patients. PURPOSE To develop a model to predict 30-day readmission in elective 1- or 2-level posterior lumbar fusion patients. STUDY DESIGN/SETTING Case control study. PATIENT SAMPLE Patients undergoing elective 1- or 2-level posterior lumbar spine fusion in the state inpatient databases (SID) of New York, Florida, North Carolina, Utah, and California. OUTCOME MEASURES Creation of the readmission after posterior spinal fusion (RAPSF) scoring system. METHODS Data were queried for 30-day readmission, as well as demographic and surgical data. Patients were randomly assigned to a derivation cohort and a validation cohort. A stepwise multivariate analysis was conducted to create a model to predict 30-day readmission. Variables with p 1.1 and p RESULTS There were 92,262 patients in the derivation cohort and 90,257 in the validation cohort. Thirty-day readmission rates were 10.9% and 11.1% respectively. The following variables were significant in the multivariate model and included in the RAPSF (point value in parentheses): age (50-59: 4, 60-69: 4, 70-79:6,>90: 8), gender (female: 3), race (Hispanic: 4, black: 5), insurance (Medicare: 4, Medicaid: 5, other–non-commercial: 3), anterior approach (4), cerebrovascular disease (3), chronic pulmonary disease (3), congestive heart failure (4), diabetes without chronic complications (4), diabetes with chronic complication (4), hemiplegia/paraplegia (7), rheumatic disease 3), drug abuse (4), electrolyte disorder (4), osteoporosis (3), depression (3), obesity (4), morbid obesity (5). Linear regression between readmission rate and RAPSF fit the derivation cohort with an adjusted r2 of 0.92 and a coefficient of 0.011 (p CONCLUSIONS We developed an easy-to-use tool, the RAPSF, to accurately predict readmission rates in patients undergoing elective 1-2 level posterior lumbar fusion. The RAPSF may be useful to empower informed choice regarding the risks of surgery and to guide an evidence-based approach to preoperative optimization and risk adjustment within alternative payment models for elective spine surgery. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Thursday, September 27, 2018 8:30 AM–9:30 AM Best Papers: 109. Healthcare utilization and costs prior to primary single-level posterior lumbar fusions: What happens before surgery?

BACKGROUND CONTEXT With an emphasis toward value-based health care, there have been multiple studies investigating postprocedural costs and their economic impact. However, often times preoperative resource utilization is overlooked and may present an opportunity for curbing excess costs and enhancing quality of care. PURPOSE There is little data with regards to preoperative costs incurred prior to a single level posterior lumbar fusion in the 2 years preceding the surgery. We sought to collate data using a national database to determine health care resource utilization prior to a single-level posterior lumbar fusion. STUDY DESIGN/SETTING This was a retrospective study done using national insurance claim records available through a subcription-based database. PATIENT SAMPLE A total of 10,281 patients undergoing primary single-level posterior lumbar fusion with active records for events occuring 2 years prior to the surgery were included in the final cohort. OUTCOME MEASURES Resource utilization was measured using per patient average reimbursements (PPAR) for each health care category with regards to pre-specified time periods. METHODS The PearlDiver Humana Database was queried for active records of patients undergoing primary single-level posterior lumbar fusions using CPT codes. Preoperative health care utilization was categorized into office visits, physical therapy, radiology, injections (facet blocks or rhizotomies or epidurals), pain medications (NSAIDS or analgesics), muscle relaxants, opioids and procedures (laminectomies). All health care utilization categories were cross-referenced with concurrent diagnoses for degenerative spine pathology to ensure relevant billing records were retrieved. The PPAR were calculated for each health care resource category with regard to specified pre-operative time periods (0-3 months, 0-6 months, 0-1year and 0-2 years). RESULTS Records of 10,281 patients, stratified as 1,408 commercial (C) and 8873 Medicare Advantage (MA) beneficiaries, undergoing primary single-level lumbar fusions were retrieved. Overall spine related care in the 2 years preceding surgery was $8,240,890 and $23,966,498 in the MA and C groups, respectively. Overall 2-year PPARs for each resource category were – office visits (MA=$887.7; C=$1132.5); physical therapy (MA=$553.8; $710.7), radiology (MA=$936.4; C=$2402), injections (MA=$1285, C=$3054.9), pain meds (MA=$127.2; C=$142.9), muscle relaxants (MA=$31.3; C=$41.5), opioids (MA=$71.2; C=$84.8) and procedures (MA=$2402.9; C=$6443.2). The majority of reimbursements for all categories occurred just before the primary procedure with results showing 37%–54% and 40%–57% of the overall PPAR/category being accounted for in the last three months for MA and C beneficiaries, respectively. Of note, 46.3% (MA)/49.5% (C) of the overall PPAR for injections and 45.2% (MA)/52.1% (C) of the overall PPAR for Opioids were accounted for in the last three months. CONCLUSIONS We observed a high utilization of spine-related care in the three months prior to a single level posterior lumbar fusion for both C and MA beneficiaries. As we move toward value based payment models, judicious use of nonsurgical interventions with proven benefit, particularly in patients that ultimately require surgical intervention, will be required to optimize cost-effectiveness. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P19. Outpatient posterior lumbar fusion: a population-based analysis of trends and complication rates

BACKGROUND CONTEXT Outpatient lumbar spine fusion is now possible secondary to minimally invasive techniques that allow for reduced hospital stays and analgesic requirements. Data is currently limited regarding the clinical outcome of outpatient lumbar fusion. PURPOSE The purpose of this study is to determine the nationwide trends and complication rates associated with outpatient posterior lumbar fusion (PLF). STUDY DESIGN/SETTING This is a retrospective case control study utilizing the Humana subset of the PearlDiver insurance records database. PATIENT SAMPLE The patient sample consisted of patients who underwent one-two level PLF (CPT-22612 or CPT-22633 AND ICD-9-816.2) as either outpatients or inpatients from Q1 2007 to Q2 2015. OUTCOME MEASURES Perioperative medical and surgical complications were identified by querying for relevant International Classification of Diseases and Current Procedural Terminology codes. METHODS The incidence of perioperative medical and surgical complications was determined after the database query was performed. Multivariate logistic regression adjusting for age, gender, and Charlson Comorbidity Index was used to calculate odds ratios (OR) of complications among outpatients relative to inpatients undergoing PLF. RESULTS Cohorts of 770 patients who underwent outpatient PLF and 26,826 patients who underwent inpatient PLF were identified. The median age was in the age 65-69 age group for both cohorts. The annual relative incidence of outpatient PLF remained stable across the study period (R2=0.03, p=.646). Adjusting for age, gender, and comorbidities, patients undergoing outpatient PLF had higher likelihood of revision/extension of posterior fusion (OR 2.33, CI 2.06–2.63, p CONCLUSIONS Outpatient lumbar fusion is uncommonly performed in the United States. Data collected from a national private insurance database demonstrate a greater risk of postoperative surgical complications including revision anterior and posterior fusion and decompressive laminectomy. Surgeons should be cautious in performing posterior lumbar fusion in the outpatient setting as the risk of revision surgery may increase in these cases.

PHP120 - Characteristics and Rate of Subsequent Lumbar Spine Fusion Surgery Among Patients Treated with Allogenic Cellular Bone Matrix for Posterior Lumbar Spinal Fusion

Published literature indicates that posterior lumbar spinal fusion (PSF) is associated with a mean 3.4-day hospital length of stay (LOS) and as high as a 6% rate of subsequent lumbar spine fusion (SLSF) within 12 months. New allograft material, such as Vivigen® Cellular Bone Matrix (CBM), combine osteoconductive, osteoinductive and osteogenic properties and may be used during spinal procedures to promote arthrodesis. This study evaluated patient characteristics, LOS and incidence of SLSF among PSF patients treated with Vivigen CBM. We queried the Premier Healthcare Database® (2013-2016) using ICD-9/10 codes to identify patients who received 1-2 level posterior lumbar fusion with a concurrent hospital charge for ViviGen CBM (LifeNet Health®, Virginia Beach, VA). Patients’ demographics, clinical characteristics, and procedural details were collected and analyzed. Hospital LOS for the index hospitalization and the incidence of SLSF within one year of index surgery were evaluated. The evaluation of SLSF included only those patients from hospitals that continuously contributed data to the database for at least one year after index PSF. This study included 685 patients with a mean (SD) age of 61.5 (12.0) years. The majority of patients were female (59.0%). Medicare was the predominant payer (52.7%) followed by commercial insurance (32.4%). Common comorbidities included hypertension (61.9%), diabetes (22.3%), depression (20.3%) and obesity (17.3%). Mean (SD) LOS was 2.8 (1.8) days. Among the 178 patients with one year follow-up hospital data after index fusion, 1.7% (95% CI: 0.3%-4.8%) had a SLSF within one year. This study provides initial real-world insights into the patient population and one-year outcomes for patients who received ViviGen during PSF. Future research with greater statistical power as well as direct comparative data will further our understanding of the value of Vivigen CBM.

Poor Nutrition Status and Lumbar Spine Fusion Surgery in the Elderly: Readmissions, Complications, and Mortality.

Retrospective database review. To quantify the medical and surgical risks associated with elective lumbar spine fusion surgery in patients with poor preoperative nutritional status and to assess how nutritional status alters length of stay and readmission rates. There has been recent interest in quantifying the increased risk of complications caused by frailty, an important consideration in elderly patients that is directly related to comorbidity burden. Preoperative nutritional status is an important contributor to both sarcopenia and frailty and is poorly studied in the elderly spine surgery population. The full 100% sample of Medicare data from 2005 to 2012 were utilized to select all patients 65 to 84 years old who underwent elective 1 to 2 level posterior lumbar fusion for degenerative pathology. Patients with diagnoses of poor nutritional status within the 3 months preceding surgery were selected and compared with a control cohort. Outcomes that were assessed included major medical complications, infection, wound dehiscence, and mortality. In addition, readmission rates and length of stay were evaluated. When adjusting for demographics and comorbidities, malnutrition was determined to result in significantly increased odds of both 90-day major medical complications (adjusted odds ratio, OR: 4.24) and 1-year mortality (adjusted OR: 6.16). Multivariate analysis also demonstrated that malnutrition was a significant predictor of increased infection (adjusted OR: 2.27) and wound dehiscence (adjusted OR: 2.52) risk. Length of stay was higher in malnourished patients, though 30-day readmission rates were similar to controls. Malnutrition significantly increases complication and mortality rates, whereas also significantly increasing length of stay. Nutritional supplementation before surgery should be considered to optimize postoperative outcomes in malnourished individuals. 3.

Can facet joint fluid on MRI and dynamic instability be a predictor of improvement in back pain following lumbar fusion for degenerative spondylolisthesis?

To investigate the relationship between lumbar facet fluid and dynamic instability in degenerative spondylolisthesis (DS), as well as the relationship between facet fluid and patient-reported outcomes following a posterior lumbar fusion. We analyzed consecutive patients with degenerative spondylolisthesis undergoing single level posterior lumbar fusion from December 2010 to January 2013 at a single academic institution. We investigated the relationship between fluid in the facet joint as measured on axial MRI and the presence of dynamic instability. We investigated the impact of facet fluid, Modic changes, and dynamic instability on patient-reported outcomes. There was a significant association between the amount of facet joint fluid and the presence of dynamic instability (p=0.03); as facet fluid increases, the probability of dynamic instability also increases. For every 1mm of facet fluid, there was a 41.6% increase (95% CI 1.8-97) in the odds of dynamic instability. A facet fluid amount less than 0.5mm gave a 90% probability that there was no dynamic instability. The presence of facet fluid and dynamic instability were associated with achieving minimal clinical important difference (MCID) in low back pain following lumbar fusion (p=0.04 and 0.05, respectively). Facet joint fluid is associated with the presence of dynamic instability in DS. The presence of facet fluid and dynamic instability may predict increased likelihood of achieving MCID for improvement in back pain following posterior lumbar fusion.

A consensus statement regarding the utilization of BMP in spine surgery.

Recombinant human bone morphogenetic protein - 2 (rh-BMP-2) was first approved by the United States Food and Drug Administration (FDA) in 2002 for use in anterior lumbar interbody fusions. Since that time, it has been estimated that "off label" use accounts for 85% of applications. Original, industry sponsored studies demonstrated superior fusion rates with decreased incidence of complications when compared with traditional iliac crest bone graft. These studies have been criticized for potential bias and newer research has detailed potential complications as well as alternative applications. Potential off label uses of rhBMP-2 include: anterior lumbar fusions, single level posterior lumbar fusions, multiple level posterior lumbar fusions, posterior cervical fusions, long deformity fusions, in the presence of vertebral osteomyelitis, and in patients with history of malignancy. A review of the literature related to rhBMP-2 was conducted to evaluate its use for the above-mentioned applications with a special focus on fusion rates, observed complications, and clinical or radiographic outcomes.

Ketamine as an Adjunct to Postoperative Pain Management in Opioid Tolerant Patients after Spinal Fusions: A Prospective Randomized Trial

Management of acute postoperative pain is challenging, particularly in patients with preexisting narcotic dependency. Ketamine has been used at subanesthetic doses as a N-methyl D-aspartate (NMDA) receptor antagonist to block the processing of nociceptive input in chronic pain syndromes. This prospective randomized study was designed to assess the use of ketamine as an adjunct to acute pain management in narcotic tolerant patients after spinal fusions. Twenty-six patients for 1-2 level posterior lumbar fusions with segmental instrumentation were randomly assigned to receive ketamine or act as a control. Patients in the ketamine group received 0.2 mg/kg on induction of general anesthesia and then 2 mcg kg(-1) hour(-1) for the next 24 hours. Patients were extubated in the operating room and within 15 minutes of arriving in the Post Anesthesia Care Unit (PACU) were started on intravenous patient-controlled analgesia (PCA) hydromorphone without a basal infusion. Patients were assessed for pain (numerical rating scale [NRS]), narcotic use, level of sedation, delirium, and physical therapy milestones until discharge. The ketamine group had significantly less pain during their first postoperative hour in the PACU (NRS 4.8 vs 8.7) and continued to have less pain during the first postoperative day at rest (3.6 vs 5.5) and with physical therapy (5.6 vs 8.0). Three patients in the control group failed PCA pain management and were converted to intravenous ketamine infusions when their pain scores improved. Patients in the ketamine group required less hydromorphone than the control group, but the differences were not significant. Subanesthetic doses of ketamine reduced postoperative pain in narcotic tolerant patients undergoing posterior spine fusions.