Faculty Bibliography

BACKGROUND CONTEXT: Adult spinal deformity (ASD) patients exhibit complex and highly variable pathology. The decision to manage patients operatively is subjective and varies based on training and experience. Machine learning algorithms have shown promise in supporting clinical decision-making. PURPOSE: We sought to develop models capable of accurately discriminating between patients receiving operative vs nonoperative treatment based only on baseline radiographic and clinical data at enrollment. STUDY DESIGN/SETTING: Retrospective analysis of a multicenter, prospectively-defined, consecutive cohort of ASD patients. PATIENT SAMPLE: A total of 1,503 patients were included in this study, divided in a 70:30 split for training and testing. OUTCOME MEASURES: Patients receiving operative treatment were defined as those undergoing surgery up to 1 year after their baseline visit.
METHOD(S): Potential predictors included available demographics, past medical history, HRQoL, and premeasured radiographic parameters from AP and lateral films. Variables with >10% missing data were discarded, and the remainder underwent median imputation. In total, 321 potential predictors were included. Random forest, elastic net regression, and support vector machines (SVMs) with radial and linear kernels were trained. Model performance was evaluated by area under the receiver operating characteristic curve (AUC).
RESULT(S): Of the patients, 69.0% (n=727) and 69.1% (n=311) in the training and testing sets received operative management, respectively. Upon evaluation with the testing dataset, performance for SVM linear (AUC=0.910), elastic net (0.913), and SVM radial (0.914) models was excellent, and the random forest model performed very well (0.830). In our SVM radial model, HRQoL metrics were particularly important for making predictions; the top 3 most important variables were SRS appearance, SRS total, and ODI.
CONCLUSION(S): This study developed models exhibiting excellent discrimination (AUC>0.9) between patients receiving operative vs nonoperative management, based solely on baseline enrollment values. HRQoL metrics were strongest in making these predictions. Future investigations may evaluate the implementation of such models for decision support in the clinical setting. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Antifibrinolytic agents are used during ASD surgery to minimize blood loss and transfusion requirements. Tranexamic acid (TXA) reduces the risk of blood loss and transfusion after ASD surgery, but there persists concern for prothrombotic effects, myocardial infarction, stroke, and postoperative neurologic events including seizures. PURPOSE: To investigate perioperative blood loss and transfusion after TXA for ASD surgery. STUDY DESIGN/SETTING: Retrospective review of prospectively collected single center database. PATIENT SAMPLE: 469 patients who received TXA, and 354 patients who did not receive TXA. OUTCOME MEASURES: Perioperative blood loss and blood product transfusion rate, and complications.
METHOD(S): Using a single-institution multi-surgeon database, we performed a retrospective review of patients undergoing ASD surgery from 2011-2018. We identified 469 patients who received TXA, and 354 patients who did not receive TXA. We investigated perioperative blood loss and blood product transfusion rate, and complications occurring after surgery.
RESULT(S): There was no significant difference in age, BMI, or frailty between the TXA (age: 45 +/- 23, BMI: 25 +/- 6) and non-TXA group (age: 47 +/- 24, BMI: 26 +/- 7). The prevalence of coronary artery disease, chronic kidney disease, and history of pulmonary embolism was higher in the non-TXA group, presumably due to surgeon preoperative screening, with no difference in other medical comorbidities. There were more revision surgeries and pelvic fixation procedures in the TXA group, with no other differences in surgical complexity. The group that received TXA had significantly lower EBL (1693 +/- 1343 mL vs 2009 +/- 1892 mL, p=0.019), and were transfused less platelets intraoperatively (.07 +/-.3 U vs 0.25 +/- 0.86 U, p=0.012). There was no difference in rates of perioperative pRBC transfusion between the groups. The most common complications in both groups were ileus and urinary retention. There was no difference in rate of thrombotic, cardiac, or renal complications, or seizures between the two groups. There was no significant difference in 90-day complication, readmission, or revision rates.
CONCLUSION(S): Among patients undergoing ASD surgery, TXA was associated with a lower estimated blood loss, without a higher risk for any morbid event. To our knowledge, this is the largest study to date to evaluate the safety of TXA for ASD surgery. FDA DEVICE/DRUG STATUS: Unavailable from authors at time of publication.
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BACKGROUND CONTEXT: Bariatric surgery for morbid obesity helps to address common comorbidity burdens, including decreasing rates of myocardial infarction and stroke. The increased mechanical stresses on the spine caused by morbid obesity predispose patients to various spinal pathologies and are concerning for spinal surgeons, with previous studies suggesting poorer outcomes than the general population. The effects of bariatric surgery on diminishing spinal complaints or symptoms have yet to be elucidated in the literature. PURPOSE: To assess the rate in which various spinal symptoms diminish after bariatric surgery. STUDY DESIGN/SETTING: Retrospective analysis of the prospectively collected New York State Inpatient Database (NYSID) years (2004-2013). PATIENT SAMPLE: A total of 4,351 patients who underwent bariatric surgery with at least one identified spinal diagnosis present before bariatric surgery. OUTCOME MEASURES: Time from bariatric surgery until disappearance of specific spinal complaint, percentage of unresolved spinal complaints with 2-year follow-up.
METHOD(S): Retrospective analysis of the prospectively collected (NYSID) years 2004-2013. Patient linkage codes allow identification of multiple and return inpatient stays within the time frame analyzed (720 days). Inclusion criteria were bariatrics surgery patients with one or more visits prior to and after bariatric procedure (excluding pts with <30 days f/u, spine surgery, or new post-bariatric spine pathology) for one of the following common cervical or lumbar spinal diagnoses, queried with ICD-9CM codes: herniation, stenosis, spondylosis, disc degeneration, and spondylolisthesis. Time from bariatric surgery until the patient's respective spinal diagnosis was no longer present was considered resolution of spinal symptoms. Kaplan-Meier survivorship curves assessed rates of resolution within each spinal diagnosis cohort.
RESULT(S): A total of 4,351 bariatric surgery pts with a preop spinal diagnosis by ICD-9 were analyzed. Lumbar pts: 1,049 had stenosis, 774 spondylosis, 648 degeneration, 249 spondylolisthesis, 72 disc herniation. Cervical pts: 581 disc herniation, 376 had stenosis, 366 spondylosis, 236 degeneration. Cumulative resolution rates at 90-day, 180-day, 360-day, and 720-day follow-up were as follows: lumbar stenosis (48%,67.6%,79%,91%), lumbar herniation (61%,77%,86%,93%), lumbar spondylosis (47%,65%,80%,93%), lumbar spondylolisthesis (37%,58%,70%,87%), lumbar degeneration (37%,56%,72%,86%). By cervical region: cervical stenosis (48%,70%,84%,94%), cervical herniation (39%,58%,74%,87%), cervical spondylosis (46%, 70%,83%, 94%), cervical degeneration (44%,64%,78%,89%). Lumbar herniation pts saw significantly higher 90d-resolution than cervical herniation pts (p<0.001). Cervical vs lumbar degeneration resolution rates did not differ @90d (p=0.058), but did @180d(p=0.034). Cervical and lumbar stenosis resolution was similar @90d & 180d, but cervical showed greater resolution by 1 year (p=0.036).
CONCLUSION(S): Over 50% of bariatric patients diagnosed with a cervical or lumbar pathology before weight-loss surgery no longer sought inpatient care for their respective spinal diagnosis by 180 days postop. Lumbar herniation had significantly higher resolution than cervical herniation by 90d, whereas cervical degeneration and stenosis resolved at higher rates than corresponding lumbar pathologies by 180d and 1-year follow-up, respectively. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Cannabis is the most commonly used illicit drug in the United States with 4 million Americans meeting clinical criteria for cannabis dependence or abuse in 2015. With recent state-level legalization efforts and changing public perception, its use is expected to grow. Considering these changes and the reported medicinally beneficial effects, studies evaluating cannabis use and its impact on outcomes following cervical fusion (CF) are quite limited; further detailed study is warranted. PURPOSE: This study sought to identify if adverse outcomes, such as complications, readmissions, and revisions, are comparable between cannabis users and noncannabis users undergoing CF. We compared 90-day complication and readmission rates and 2-year revision rates between baseline cannabis users and nonusers following CF. STUDY DESIGN/SETTING: Retrospective cohort study of a prospectively collected database. PATIENT SAMPLE: All patients who underwent CF between January 2009 and September 2013 in the New York Statewide Planning and Research Cooperative System (SPARCS) were identified. Patients were included if they had <=90-day follow-up for complications and readmissions, or >=2-year follow-up for revisions. Patients with a preoperative ICD-9-CM diagnosis of cannabis abuse (Cannabis) or dependence were identified. Patients were excluded for systemic disease, osteomyelitis, cancer, trauma, or concomitant substance or polysubstance abuse/dependence. OUTCOME MEASURES: Demographic information, fusion approach, fusion levels, complications, readmissions, and revisions.
METHOD(S): All patients aged >=18y who underwent CF from 2009-13 were identified via the SPARCS database and included if they had <=90D follow-up for complications and readmissions or 2Y follow-up for revisions. Pts with preoperative cannabis abuse/dependence identified (Cannabis). Pts were excluded for systemic disease, osteomyelitis, cancer, trauma, or concomitant substance or polysubstance abuse/dependence. Following patient selection in the SPARCS database, Cannabis patients were 1:1 propensity score-matched by age, gender, race, Deyo score, fusion levels and approach, and tobacco use to nonusers (Non-Cannabis). These groups were compared for hospital-related parameters, rates of 90-day complications and readmissions, and 2-year revisions. Multivariate binary stepwise logistic regression models identified independent predictors of these outcomes.
RESULT(S): A total of 432 pts (n=216 each) were identified, with comparable age, sex, Deyo scores, tobacco use rates, and distribution of anterior or posterior approach (all p>0.05). Cannabis patients were more frequently African American (27.8% vs 12.0%), primarily utilized Medicaid (29.6% vs 12.5%), and incurred longer lengths of stay (3.0 vs 1.9 days), all p<=0.001. Both cohorts experienced comparable rates of 90-day medical, surgical and overall complications (5.6% vs 3.7%) and 2-year revisions (4.3% vs 2.8%), p<=0.430. Cannabis users experienced higher 90-day readmission rates (11.6% vs 6.0%, p=0.042). Cannabis use was an independent predictive factor of 90-day readmission (OR=2.0, 95%CI, 1.0-4.1, p=0.049), but did not predict any 90-day complications or 2-year revisions (all p>0.05).
CONCLUSION(S): Baseline cannabis dependence/abuse was associated with increased 90-day readmission odds following CF. Further investigation of the physiologic impact of cannabis on musculoskeletal patients may identify what measurable or overlooked patient factors contribute to this association. FDA DEVICE/DRUG STATUS: Unavailable from authors at time of publication.
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BACKGROUND CONTEXT: Lateral interbody fusion (LLIF) is often performed with biologic adjuvants to promote fusion. Commercially available bone allograft containing allogeneic stem cells (ASC) and bone morphogenetic protein-2 (BMP) are designed to promote fusion while avoiding the morbidity of iliac crest autograft; however, no study to date has directly compared the two in LLIF. The ASC studied is Osteocel Pro (NuVasive, Inc). PURPOSE: This non-industry funded study compares fusion rate, complications, and costs between LLIF with BMP and ASC. STUDY DESIGN/SETTING: Single center retrospective comparative study. PATIENT SAMPLE: Patients with 1-3 lumbar levels treated with LLIF. OUTCOME MEASURES: Outcomes measures are fusion at 1 year postoperative, complication rates, length of stay, and costs.
METHOD(S): A retrospective chart review was conducted to identify patients treated with LLIF and ASC or BMP from February 2012 through September 2017. Patients were included who had from 1-3 lumbar levels treated with LLIF and at least 1 year of radiographic follow up. Interbody fusion was assessed on lumbar X-ray images using a validated scale.
RESULT(S): A total of 94 patients were included representing 162 levels fused. Of these, 74 patients and 133 levels were treated with BMP; 20 patients and 29 levels were treated with ASC. Comparing patients treated with BMP or ASC, there were no differences in age [61.6 vs 60.4, p=0.7], BMI [29.8 vs 28.3, p=0.3], gender [60.8% vs 55.0% female], smoking status [12.2% vs 10.0%, p=1], diabetes [28.4% vs 15.0%, p=0.2], Charleston Comorbidity Index [4.3 vs 3.5, p=0.2], revision status [47.3% vs 45.0%, p=0.9], intraoperative complications [4.1% vs 5.0%, p=1], postoperative complications [37.8% vs 30.0%, p=0.5], or blood loss [881 vs 528ml, p=0.2]. More levels were fused in the BMP group (1.8 vs 1.45, p=0.04) and the BMP group tended toward a longer length of stay [4.8 vs 3.8 days, p=0.06]. There was a nonsignificant trend toward a higher fusion rate with BMP vs ASC[98.5% vs 93.1%, p=0.1]. The average amount of rhBMP used per level was 2.0 cc compared to 5.9 cc of ASC. There was no difference in the cost of the BMP per level compared with ASC [4.45% vs 4.80%, p=0.33], but the BMP group tended toward a higher cost of total care [103.5% vs 87.6%, p=0.1].
CONCLUSION(S): ASC and BMP are both acceptable adjuvants in LLIF that demonstrate comparable fusion rates at 1 year with comparable cost in the setting of similar groups of patients. The radiographic fusion rate seen in our study compares to previous reports in the literature using ASC. Cost considerations are becoming ever more cogent in spine surgery; the results of this study can inform decision making regarding which biologic adjuvant to use in lumbar interbody fusion. FDA DEVICE/DRUG STATUS: Osteocel (Approved for this indication), rhBMP (Infuse) (Not approved for this indication)
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BACKGROUND CONTEXT: The Adult Spinal Deformity Invasiveness Index incorporates deformity-specific components to assess the magnitude of correction. It's unknown how invasiveness relates to outcomes in each frailty state. PURPOSE: Investigate the relationship between increasing invasiveness and outcomes in ASD surgery in each frailty states. STUDY DESIGN/SETTING: Retrospective review of prospective, consecutively enrolled multicenter ASD database. PATIENT SAMPLE: A total of 195 ASD patients with baseline demographic and surgical details. OUTCOME MEASURES: Invasiveness, frailty, minimal clinically important differences (MCID) for the Oswestry Disability Index, SF-36 Physical Component Scores, and Scoliosis Research Society Scores.
METHOD(S): ASD patients (scoliosis >=20degree, SVA >=5cm, PT >=25degree, or TK >=60degree) with baseline frailty and invasiveness scores. Invasiveness index included; posterior: decompression (1), fusion (2), instrumentation (1), osteotomies: 3-coloumn (14), Ponte (1), interbody fusion; anterior lumbar (8), transforaminal/posterior lumbar (2), iliac fixation (2), revision surgery (3). Invasiveness scores were calculated within different frailty states (not frail, NF, <0.3), frail (F, 0.3-0.5), severely frail (SF, >0.5). Logistic regression analysis assessed the relationship between increasing invasiveness and major complications or reoperations and meeting MCID for any of the measured HRQLs at 3 years. Decision tree analysis assessed thresholds for an invasiveness risk benefit cutoff point, above which experiencing complications or reoperations and not reaching MCID were higher. Significance was set to p<0.05.
RESULT(S): One hundred ninety-five of 322 patients met inclusion criteria. Baseline demographic info: age 59.9 +/- 14.4, 75% female, BMI 27.8 +/- 6.2, CCI 1.7 +/- 1.7. Baseline surgical info: 61% osteotomy, 52% decompression, 11.0 +/- 4.1 levels fused. There were 98 NF, 65 F, and 30 SF patients. For the entire cohort, binary regression analysis found a significant relationship between increasing invasiveness and experiencing a major complication or reoperation (1.01 [1.00-1.02], p=0.01). Within each frailty subgroup, the results were 1.01 ([1.00-1.03], p=0.05) for NF, 1.01 ([1.01-1.02], p<0.001) for F, and 1.01 ([1.00-1.01], p=0.02) for SF. When defining no major complications or reoperation and meeting MCID in any HRQL at 3 years as a favorable outcome, decision tree analysis established an invasiveness risk benefit cutoff of 63.9. Patients below this threshold were 1.8 [1.38-2.35] (p<0.001) times more likely to not have a major complication/reoperation and meet MCID at 3 years. Invasiveness above this point was a negative predictor (0.55 [0.401-0.754], p<0.001). When factoring in frailty, for NF patients the risk benefit cutoff was 79.3 (2.11 [1.39-3.20] (p<0.001), 111 for F (2.62 [1.70-4.06] (p<0.001), and 53.3 for SF (2.35 [0.78-7.13] (p=0.13).
CONCLUSION(S): Increasing invasiveness is associated with increased odds of major complications and reoperations. A risk/benefit cutoff for decreasing major complications/reoperations and meeting MCID was found to be 79.3 for NF patients, 111 for F patients, and 53.3 for SF patients. Above these thresholds, increasing invasiveness is associated with increasing the risk of major complications or reoperations and not meeting MCID at 3 years. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Spinal and body balance are active processes requiring a thorough understanding of the harmony between static posture and dynamic motion. Our understanding of patients' function is lacking a more objective and quantified mechanism of assessment. The Dubousset Functional Test (DFT) is a four-component, novel, multidomain physical function and balance assessment proposed by Dr. Jean Dubousset. PURPOSE: To identify normative baseline/reference values for DFT in asymptomatic, healthy subjects, establish test feasibility, and identify correlations between demographics and DFT performance in the general population. STUDY DESIGN/SETTING: Prospective single-center. PATIENT SAMPLE: Sixty-five asymptomatic volunteers (mean age: 42.4+/-15.4 years; 42% female, mean BMI 26+/-4.8kg/m2). OUTCOME MEASURES: Demographics, DFT components: Up-and-Walking Test (UWT), Steps Test (ST), Down-and-Sitting Test (DST), Dual-Tasking Test (DTT).
METHOD(S): Asymptomatic volunteers were screened and recruited to participate in the 4 DFT components at a single center from 2017-2018. These include: (1) UWT (Up-and-Walking Test): unassisted sit-to-stand, walk forward/backward 5 m (no turn), unassisted sit; (2) ST (Steps Test): ascend 3 steps, turn, descend 3 steps; (3) DST (Down-and-Sitting Test): stand-to-ground sit-to-stand, assistance as needed; (4) DTT (Dual-Tasking Test): walk 5 m forth and back while counting down from 50 by 2. All subjects were given standardized verbal instructions and a physical demonstration for each DFT test. Trials were video recorded and timed, with scores assigned by time required to complete the test. All trials were conducted and all tests were scored by the same rater. Univariate and multivariate analysis were utilized to analyze durations of test components against demographics.
RESULT(S): 65 subjects were included (mean age, 42.4+/-15.4 years); 42% were female, and mean BMI was 26+/-4.8 kg/m^2. The racial breakdown of the cohort was 34% White, 25% Black, 15% Asian, 9% Indian, 6% Latino, 10% other. Evaluating the four components of the DFT, the mean and standard deviations of each test component were as follows: mean duration in seconds and 95% confidence interval of each DFT test: UWT: 14.8s (14.0-15.6s), ST: 6.3s (6.0-6.6s), DST: 6.0s (5.4-6.6s), and DTT: 12.8s (12.1-13.6s). There were no differences between males and females in time taken to perform any of the tests. There were significant correlations between age and DST (r=0.529), UWT (r=0.429), and ST (r=0.356) (all p<0.05), with no correlation found with DTT. A similar trend was found with respect to correlation with BMI (r=0.372, r=0.289, and r=0.366, p<0.05), with no correlation again found with DTT. With respect to DTT specifically, patients on average finished countdown from 50 to 29.7+/-5.3. 12.3% of subjects exhibited physical pausing during the DTT, and 87.5% of those were pauses occurred while turning. Among total subjects, 32.3% exhibited verbal pausing/stuttering/mistakes in counting during the Dual Tasking test; of these, 62% occurred while turning.
CONCLUSION(S): The DFT is a quick and feasible test that was performed safely in a cohort of healthy subjects. Age and BMI, but not gender, were found to influence all DFT tests. Physical and verbal pausing were reported in about 1/10 and 1/3 patients, respectively, with the majority of pausing occurring during the turning phase of the test. Utilization of this test in patients with spinal pathologies may help us to determine the offset from norms as well as understand the impact of preoperative DFT performance on surgical outcomes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Sagittal malalignment has been discussed extensively in adult spinal deformity (ASD) literature, while coronal malalignment (CM) and fractional curve (FC) have received less attention. As a result, little guidance currently exists for surgical indications in managing CM, despite it being a relatively common occurrence that can considerably impact patient wellbeing. Patients with CM significantly affected by FC are at particular risk for continued CM postoperatively, along with its complications. PURPOSE: Assess types of approach to fusion of the fractional curve in ASD surgery and their relation to coronal alignment and sagittal alignment. STUDY DESIGN/SETTING: Retrospective review at single institution. PATIENT SAMPLE: A total of 82 ASD patients undergoing primary spinal fusion of 4 or more levels to sacrum or pelvis. OUTCOME MEASURES: Baseline (BL), 1-year (Y1) postoperatively and BL-Y1 difference (DELTABL-Y1) in magnitudes of FC, coronal alignment (CA) and sagittal alignment (SA) parameters: pelvic incidence-LL (PI-LL), cervical sagittal vertical axis (cSVA), T1 pelvic angle (TPA).
METHOD(S): Patients >=18 years old undergoing primary >=4-level fusion to sacrum/pelvis between October 2011 and January 2018 with minimum 6-month follow-up included. Chart review performed for operative dates and details and patient follow-up information. Coronal and sagittal parameters measured using deformity measuring software program. FC measured as segmental angle between L4 and S1. CA measured as distance between C7 plumb line and central sacral vertical line. CA>=20mm designated as CM, per guidelines in literature. Chi-squared test used to compare percentages and ANOVA used to compare means, with significance set at p<0.05.
RESULT(S): A total of 82 patients studied (68.3%F, age 62.6+/-13.3, BMI 28.1+/-6.6, Charlson comorbidity index 0.80+/-1.16). Nine patients (10.98%) had anterior-posterior fusion (AP), 41 (50%) posterior-only fusion with interbody device (PIB), 32 (39.02%) PSF without interbody (PSF). Twenty-three patients (28.04%) had FC>=15degree at BL, 7 (8.54%) at Y1. Forty-one patients (50%) had CM at BL, 35 (42.68%) at Y1. AP fusion patients had least levels fused (6.4 AP, 11.4 PIB, 11.8 PSF, p<0.001). No difference in revision by approach (55.56% AP, 24.39% PIB, 28.13% PSF, p=0.179). Approach type was not associated with different BL, Y1 or DELTABL-Y1 alignment parameters for FC, CA or SA. Mean FC 9.89degree at BL, 6.91degree at Y1 and DELTABL-Y1 difference 5.77degree, no difference between approach groups (p=0.361, 0.127, 0.550, respectively). Mean value for CA 33.62mm at BL, 21.15mm at Y1 and DELTABL-Y1 difference 23.23mm, no difference between approach groups (p=0.087, 0.153, 0.206, respectively). Mean PI-LL 25.21degree at BL, 11.1degree at Y1 and DELTABL-Y1 difference -13.7degree, no difference between approach groups (p=0.503, 0.600, 0.356, respectively). Mean cSVA 27.53degree at BL, 28.85degree at Y1 and DELTABL-Y1 difference 1.29degree, no difference between approach groups (p=0.364, 0.099, 0.141, respectively). Mean TPA 28.37degree at BL, 21.12degree at Y1 and DELTABL-Y1 difference -6.63degree, no difference between approach groups (p=0.066, 0.248, 0.138, respectively).
CONCLUSION(S): Fusion to the sacrum/pelvis improves sagittal alignment, fractional curve and coronal alignment in most patients. However, while fractional curve and sagittal alignment are better corrected, coronal malalignment, particularly more severe malalignment at baseline, tends to persist postoperatively. Type of approach and use of interbody device does not appear to significantly impact these results. This should be considered in preoperative planning for patients with coronal deformity. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Cannabis is the most commonly used illicit drug in the United States, and with changing state legislation, the use of cannabis is expected to expand. Although other literature has noted potentially medicinally beneficial effects of cannabis, there is limited literature evaluating the impact of cannabis on outcomes for patients following spinal surgery. With shifting public sentiment, expanding decriminalization, and a dearth of knowledge on the potential surgical implications of cannabis, it is imperative we take a closer, objective look at how cannabis dependence or abuse impacts the outcomes of common orthopedic procedures, such as thoracolumbar fusion. PURPOSE: To determine if adverse outcomes would be comparable between baseline cannabis users and non-cannabis users undergoing thoracolumbar spinal fusion. We compared the rates of 90-day outcomes and complications and 2-year revisions between baseline cannabis users and non-users following thoracolumbar spinal fusion. STUDY DESIGN/SETTING: Retrospective cohort study of a prospectively-collected database. PATIENT SAMPLE: The New York State Statewide Planning and Research Cooperative System (SPARCS) was queried to identify all patients from January 2009 to September 2013 who underwent thoracolumbar spinal fusion. Patients were included if they had <=90-day follow-up for complications and readmissions or >=2-year follow-up for revisions. Patients with preoperative cannabis abuse/dependence were identified. Patients were excluded for systemic disease, osteomyelitis, cancer, trauma, or concomitant substance or polysubstance abuse/dependence. OUTCOME MEASURES: Demographic information, fusion approach, fusion levels, complications, readmissions, and revisions.
METHOD(S): The NYS SPARCS database was queried to identify all patients >=18y who underwent thoracolumbar spinal fusion from 2009-13. Patients were included if they had <=90D FU for complications and readmissions or 2Y FU for revisions. Patients with preoperative cannabis abuse/dependence were identified. Patients were excluded for systemic disease, osteomyelitis, cancer, trauma, or concomitant substance or polysubstance abuse/dependence. Following patient identification in the SPARCS database, patients with ICD-9-CM diagnosed cannabis use were 1:1 propensity score-matched by age, gender, race, Deyo score, fusion levels and approach and tobacco use to non-cannabis users. These groups were compared for hospital-related parameters, rates of 90-day complications and readmissions and 2-year revisions. Multivariate binary stepwise logistic regression models identified independent predictors of outcomes.
RESULT(S): A total of 628 patients (n=314 each) were identified and included; patients had comparable age, gender, fusion approaches and fusion levels distribution. More cannabis patients were African American (19.7 vs 7.6%) and primarily utilized Medicaid (24.2% vs 11.5%), all p<=0.001. Non-cannabis patients incurred lower 90-day overall and medical complication rates (5.1% vs 12.1%; 4.5% vs 9.9%), all p<0.01. Regression revealed baseline cannabis use as a negative independent predictor of any 90-day medical complications (OR=0.43, p=0.01). Baseline cannabis use was not associated with increased surgical or overall 90-day complications, 90-day readmissions or 2-year revisions.
CONCLUSION(S): Cannabis was a protective factor against postoperative anemia and any medical complication, and baseline cannabis use was not associated with increased surgical or overall 90-day complications and readmissions or 2-year revision rates. These findings underscore that baseline cannabis use in the absence of acute intoxication may not necessarily require delays in preoperative clearance. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
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BACKGROUND CONTEXT: Adult Spinal Deformity (ASD) surgery is associated with a high cost. Previous studies have suggested that the actual direct hospital cost of ASD surgery is higher than the Medicare Allowable (MA) rate. MA rates are becoming the benchmark reimbursement target for hospital accounting systems. It is important to determine what factors can predict which ASD patients have actual costs below Medicare reimbursement. PURPOSE: Our goal is to (1) determine if we can develop a model to predict when index episode of care (iEOC) surgical costs of ASD surgeries are below the MA threshold and (2) to identify potentially modifiable variables. STUDY DESIGN/SETTING: Retrospective analysis of a prospective multi-center ASD database. PATIENT SAMPLE: Adult spinal deformity patients undergoing surgical correction enrolled into a prospective, multicenter surgical database from 2008-2014. OUTCOME MEASURES: Primary outcome measure is iEOC costs and patient and hospital-specific MA reimbursements, but other baseline HRQOL outcome measures were collected such as Oswestry Disability Index (ODI), SF-36 PCS, and SF-36 MCS.
METHOD(S): From a prospective, multicenter ASD surgical database, patients undergoing long instrumented fusions (>4 level) with cost data were identified. Index episode of care (iEOC) cost was calculated by utilizing actual direct hospital cost. MA rates were calculated using the year-appropriate CMS Inpatient Pricer Payment System Tool and were hospital specific. Demographic, baseline HRQOL, radiographic and surgical variables were analyzed. A predictive model was developed to identify variables that can predict iEOCRESULT(S): Administrative direct cost data was obtained from 4 of 11 centers with a total of 195 patients included in the model. A total of 109 (55%) patients had iEOC below the MA threshold. There was significant variation across the 4 centers in both the mean iEOC cost ($56,788 to $78,878,p<0.001) and reimbursement ($40,623 to $91,351, p<0.001) which was seen across deformity-specific DRGs (453,454,456,457). Academic centers were more likely to have iEOC costs below reimbursement (66.7% vs 8.9%, p<0.001). The model showed excellent fit and calibration with an AUC of 94.48% [95%CI 91.59-97.38]. Negative predictors included number of levels fused (OR 0.61, 95%CI [0.48-0.75], p <0.001) and DRG 457 (OR 0.016, 95%CI [0.0-0.20], p = 0.0016) while having a revision surgery (OR 3.61, [1.06-13.58], p=0.045) and at an academic center (OR 19.6 95%CI [8.81-50.7], p <0.001) were positive predictors. The marginal effect for additional levels fused is -4.38%, meaning for each additional level fused, the likelihood of the iEOCCONCLUSION(S): There is significant institutional variation in ASD cost and reimbursement with an increased likelihood of 56.8% getting reimbursed more than the cost of surgery (iEOCCopyright