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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.

BACKGROUND Early aseptic revision within 90 days after primary TKA is a devastating complication. The causes, complications, and rerevision risks of aseptic revision TKA performed during this period are poorly described. QUESTIONS/PURPOSES (1) What is the likelihood of re-revision within 2 years after early aseptic TKA revision within 90 days compared with that of a control group of patients undergoing primary TKA? (2) What are the indications for early aseptic TKA revision within 90 days? (3) What are the differences in revision risk between different indications for early aseptic revision TKA? METHODS Patients who underwent unilateral aseptic revision TKA within 90 days of the index procedure were identified in a national insurance claims database (PearlDiver Technologies) using administrative codes. The exclusion criteria comprised revision for infection, history of bilateral TKA, and age younger than 18 years. The PearlDiver database was selected for its large and geographically diverse patient base and the availability of outpatient follow-up data that are unavailable in other databases focused on inpatient care. A total of 481 patients met criteria for early aseptic revision TKA, with 14% (67) loss to follow-up at 2 years. This final cohort of 414 patients was compared with a control group of patients who underwent primary TKA without revision within 90 days. For the control group, 137,661 patients underwent primary TKA without early revision, with 13% (18,138) loss to follow-up at 2 years. Among these patients, 414 controls were matched using a one-to-one propensity score method; no differences in age, gender, and Charlson comorbidity index score were observed between the groups. Indications for initial revision and 2-year re-revision were recorded. The Kaplan-Meier method was used to assess survival between the early revision and control groups. RESULTS Two-year survivorship free from additional revision surgery was lower in the early aseptic revision cohort compared with the control (78% [95% confidence interval 77% to 79%] versus 98% [95% CI 96% to 99%]; p < 0.001). Among early revisions, 10% (43 of 414) of the patients underwent re-revision for periprosthetic infection with an antibiotic spacer within 2 years. The reasons for early aseptic revision TKA were instability/dislocation (37% [153 of 414]), periprosthetic fracture (23% [96 of 414]), aseptic loosening (23% [95 of 414]), pain (11% [45 of 414]), and arthrofibrosis (6% [25 of 414]). Early revision for pain was associated with higher odds of re-revision than early revisions performed for other all other reasons (44% [20 of 45] versus 29% [100 of 344]; odds ratio 2.0 [95% CI 1.0 to 3.7]; p = 0.04). CONCLUSION Acute early aseptic revision TKA carries a high risk of re-revision at 2 years and a high risk of subsequent periprosthetic joint infection. Patients who undergo an early revision should be carefully counseled regarding the very high risk of repeat revision and discouraged from having early revision unless the indications are absolutely clear and compelling. Early aseptic revision for pain alone carries an unacceptably high risk of repeat revision and should not be performed. Adjunctive measures for infection prophylaxis should be strongly considered. Specific interventions to reduce surgical complications in this subset of patients have not been adequately studied; additional investigation of strategies to minimize the risk of reoperation or infection is warranted. LEVEL OF EVIDENCE Level III, therapeutic study.

Introduction Although one of the touted benefits of the direct anterior approach (DAA) includes decreased postoperative pain, there is no consensus on the effect of surgical approach on postoperative pain and subsequent analgesic consumption. Methods Consecutive patients undergoing total hip arthroplasty by a single surgeon from May 2016 to March 2020 were identified. Procedures were categorized as DAA or posterior approach. Patient demographics and surgical details were assessed. Patient-reported maximum pain by postoperative day (POD), total opioid consumption during hospitalization, and whether the patient required a refill of opioid prescription within 3 months after discharge were compared between the two surgical approaches through multivariate analyses. Results A total of 611 patients were included in this study (447 DAA and 164 posterior approaches). On multivariate analyses that controlled for preoperative/intraoperative differences, patients in the DAA group had lower average maximum reported pain (0 to 10 scale) on POD #0 (6.5 versus 6.8, P = 0.034) and POD #1 (5.4 versus 6.1, P = 0.018). However, the DAA was not associated with a statistically significant reduction in total inpatient oral morphine equivalents consumed (79.8 versus 100.1, P = 0.486). Furthermore, there was no association between surgical approach and opioid prescription refill within 3 months after discharge (P = 0.864). Discussion The DAA was associated with slightly lower patient-reported pain. Furthermore, statistical analysis did not provide the necessary evidence to reject the null hypothesis, which was that there would be no difference in opioid utilization between the two approaches. Other perioperative factors may be more important to opioid use reduction than the surgical approach alone.

The last decade has seen increasing initiatives to improve health care delivery while decreasing financial expenditures, as particularly exemplified by the implementation of bundled payments for lower extremity arthroplasty, which hold the providers responsible for the both the quality and cost of these procedures. In this context, the utility of routine preoperative laboratory testing is unknown. The present study characterizes the associations, if any, between preoperative sodium, blood urea nitrogen (BUN), and creatinine values and the occurrence of general health adverse outcomes following total hip arthroplasty (THA).Patients undergoing primary THA were identified in the 2011-2015 National Surgical Quality Improvement Program. Cases with traumatic, oncologic, or infectious indications were excluded. Preoperative levels of sodium, BUN, and creatinine were tested for associations with perioperative adverse events and adverse hospital metrics using multivariate regressions that adjusted for patient baseline characteristics.A total of 92,093 patients were included, of which 5.25% had an abnormal preoperative sodium level, 24.20% had an abnormal preoperative BUN level, and 11.95% had an abnormal preoperative creatinine level. Abnormal preoperative sodium levels (odds ratios: 1.23-1.50, p 0.007) and creatinine levels (odds ratios: 1.27-1.55, p 0.007) were associated with the occurrence of all studied adverse outcomes and abnormal preoperative BUN levels (odds ratios: 1.15-1.52, p 0.007) were associated with the occurrence of all adverse outcomes except for hospital readmission.Abnormal preoperative laboratory testing is significantly associated with adverse outcomes following THA, supporting the added value of laboratory evaluation of patients before elective arthroplasty procedures.Clinical, Level III.

STUDY DESIGN Retrospective study of prospectively collected data. OBJECTIVE To determine the incidence, timing, risk factors, and clinical implications of postoperative hematoma requiring reoperation after anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA Postoperative hematomas requiring reoperation are rare but potentially catastrophic complications after ACDF. However, there has been a lack of large cohort studies investigating these complications in the ACDF population despite increasing outpatient procedure volume. METHODS Patients who underwent ACDF in the 2012 to 2016 National Surgical Quality Improvement Program database were identified. The primary outcome was an occurrence of hematoma requiring reoperation within 30 days postoperatively. Risk factors for this outcome were identified using multivariate regression. Postoperative length of stay, subsequent complications, and mortality were compared between patients who did and did not develop a hematoma requiring reoperation. RESULTS A total of 37,261 ACDF patients were identified, of which 148 (0.40%) developed a hematoma requiring reoperation (95% confidence interval [CI], 0.33%-0.46%). Of the cases that developed this complication, 37% occurred after discharge. Risk factors for the development of hematoma requiring reoperation were multilevel procedures (most notably ≥3 levels, relative risk [RR] = 3.14, 95% CI = 1.86-5.32, P 1.2 (RR = 2.85, 95% CI = 1.42-5.71, P = 0.006), lower BMI (notably body mass index ≤24, RR = 2.11, 95% CI = 1.21-3.67, P = 0.008), American Society of Anesthesiologists classification ≥3 (RR = 2.07, 95% CI = 1.47-2.91, P

Background: Surgical treatment for lumbar degenerative spondylolisthesis has been shown to provide better long-term outcomes than conservative treatment. However, there is variation in surgical approaches employed by surgeons. This study investigates current surgical practice patterns and compares perioperative outcomes of 3 common surgical treatments for this pathology. Methods: A survey was administered to surgeons who attended the Lumbar Spine Research Society (LSRS) meeting in 2014. Data were extracted from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) from 2005 to 2014 to characterize the same responses. The 2 data sets were compared. Perioperative outcomes of those in the ACS-NSQIP posterior fusion subcohorts were characterized and compared. Results: Posterior surgical approaches utilized by surgeons who responded to the LSRS survey were similar to those captured by ACS-NSQIP where 72% of those with degenerative spondylolisthesis were fused. Of those that were fused, 8% had an uninstrumented posterior fusion, 33% had an instrumented posterior fusion, and 59% had an instrumented posterior fusion with interbody. On multivariate analysis, there was no difference in risk of postoperative adverse events, readmission, or length of stay between these 3 common types of fusion. Conclusions: Practice patterns for the posterior management of lumbar degenerative spondylolisthesis were similar between LSRS survey responses and ACS-NSQIP data. The ACS-NSQIP perioperative outcome measures assessed were similar regardless of surgical technique. These findings highlight that cost-benefit considerations and longer-term outcomes have to be the measures by which surgical technique is chosen for degenerative spondylolisthesis.

Background Context Posterior lumbar fusion (PLF) is a commonly performed procedure. The evolution of bundled payment plans is beginning to require physicians to more closely consider patient outcomes up to 90 days after an operation. Current quality metrics and other databases often consider only 30 postoperative days. The relatively new Healthcare Cost and Utilization Project Nationwide Readmissions Database (HCUP-NRD) tracks patient-linked hospital admissions data for up to one calendar year. Purpose To identify readmission rates within 90 days of discharge following PLF and to put this in context of 30 day readmission and baseline readmission rates. Study Design Retrospective study of patients in the HCUP-NRD. Patient Sample Any patient undergoing PLF performed in the first 9 months of 2013 were identified in the HCUP-NRD. Outcome Measures Readmission patterns up to a full calendar year after discharge. Methods PLFs performed in the first 9 months of 2013 were identified in the HCUP-NRD. Patient demographics and readmissions were tracked for 90 days after discharge. To estimate the average admission rate in an untreated population, the average daily admission rate in the last quarter of the year was calculated for a subset of PLF patients who had their operation in the first quarter of the year. This study was deemed exempt by the institution's Human Investigation Committee. Results Of 26,727 PLFs, 1,580 patients (5.91%) were readmitted within 30 days of discharge and 2,603 patients (9.74%) were readmitted within 90 days of discharge. Of all readmissions within 90 days, 54.56% occurred in the first 30 days. However, if only counting readmissions above the baseline admission rate of a matched population from the 4th quarter of the year (0.08% of population/day), 89.78% of 90 day readmissions occurred within the first 30 days. Conclusions The current study delineates readmission rates after PLF and puts this in the context of 30-day readmission rates and baseline readmission rates for those undergoing PLF. These results are important for patient counseling, planning, and preparing for potential bundled payments in spine surgery.

The incidence of periprosthetic hip fractures is increasing due to higher numbers of total hip arthroplasties being performed. Unlike native hip fractures, the effect of time to surgery of periprosthetic hip fractures is not well established. This study evaluates the effect of time to surgery on perioperative complications for patients with periprosthetic hip fractures.Patients who underwent surgery for periprosthetic hip fracture were identified in the 2005-2016 National Surgical Quality Improvement Program database and stratified into 2 groups:2 and ≥2 days from hospital admission to surgery. Multivariate regressions were used to compare risk for perioperative complications between the 2 groups. Independent risk factors for postoperative serious adverse events were characterized.In total, 409 (2 days from admission to surgery) and 272 (≥2 days from admission to surgery) patients were identified. Multivariate analysis revealed only higher risk of extended postoperative stay for patients who had delays of ≥2 days to surgery compared to those who had2 days from admission to surgery. Independent risk factors for serious adverse events included increasing age, dependent preoperative functional status, and preoperative congestive heart failure, but not time to surgery.Unlike for native hip fractures, time to surgery for periprosthetic hip fractures does not appear to affect most 30-day perioperative complications. However, it is worth noting that this study was unable to control for all potential confounders and therefore the results may not be generalizable to all types of periprosthetic hip fractures.

INTRODUCTION There has been a lack of studies investigating the perioperative course of total shoulder arthroplasty (TSA) performed in the increasingly octogenarian (≥80 years old) population in a large sample size. The purpose of this study was to compare perioperative complications between primary TSA performed in octogenarians and that performed in younger populations (

BACKGROUND Comorbidity indices like the modified Charlson Comorbidity Index (mCCI) and the modified Frailty Index (mFI) are commonly reported in large database outcomes research. It is unclear if they provide greater association and discriminative ability for postoperative adverse events after total shoulder arthroplasty (TSA) than simple variables. QUESTIONS/PURPOSES Using a large research database to examine postoperative adverse events after anatomic and reverse TSA, we asked: (1) Which demographic/anthropometric variable among age, sex, and body mass index (BMI) has the best discriminative ability as measured by receiver operating characteristics (ROC)? (2) Which comorbidity index, among the American Society of Anesthesiologists (ASA) classification, the mCCI, or the mFI, has the best ROC? (3) Does a combination of a demographic/anthropometric variable and a comorbidity index provide better ROC than either variable alone? METHODS Patients who underwent TSA from 2005 to 2015 were identified from the National Surgical Quality Improvement Program (NSQIP). This multicenter database with representative samples from more than 600 hospitals in the United States was chosen for its prospectively collected data and documented superiority over administrative databases. Of an initial 10,597 cases identified, 70 were excluded due to missing age, sex, height, weight, or being younger than 18 years of age, leaving a total of 10,527 patients in the study. Demographics, medical comorbidities, and ASA scores were collected, while BMI, mCCI and mFI were calculated for each patient. Though all required data variables were found in the NSQIP, the completeness of data elements was not determined in this study, and missing data were treated as being the null condition. Thirty-day outcomes included postoperative severe adverse events, any adverse events, extended length of stay (LOS, defined as > 3 days), and discharge to a higher level of care. ROC analysis was performed for each variable and outcome, by plotting its sensitivity against one minus the specificity. The area under the curve (AUC) was used as a measure of model discriminative ability, ranging from 0 to 1, where 1 represents a perfectly accurate test, and 0.5 indicates a test that is no better than chance. RESULTS Among demographic/anthropometric variables, age had a higher AUC (0.587-0.727) than sex (0.520-0.628) and BMI (0.492-0.546) for all study outcomes (all p < 0.050), while ASA (0.580-0.630) and mFI (0.568-0.622) had higher AUCs than mCCI (0.532-0.570) among comorbidity indices (all p < 0.050). A combination of age and ASA had higher AUCs (0.608-0.752) than age or ASA alone for any adverse event, extended LOS, and discharge to higher level of care (all p < 0.05). Notably, for nearly all variables and outcomes, the AUCs showed fair or moderate discriminative ability at best. CONCLUSION Despite the use of existing comorbidity indices adapted to large databases such as the NSQIP, they provide no greater association with adverse events after TSA than simple variables such as age and ASA status, which have only fair associations themselves. Based on database-specific coding patterns, the development of database- or NSQIP-specific indices may improve their ability to provide preoperative risk stratification. LEVEL OF EVIDENCE Level III, diagnostic study.

Background: Although publication rates from multiple orthopedic research conferences have been published in the literature, the publication rates of abstracts presented at the Lumbar Spine Research Society (LSRS) meetings have never been reported. The purpose of this study is to evaluate the publication rates from the LSRS annual meeting years 2008–2012 and then to compare those rates with that of other spine research society meetings. Methods: Podium presentations from 2008 to 2012 and poster presentations from 2010 to 2012 were reviewed. For each presentation, a PubMed search was performed to determine if a full-text publication existed. χ2 tests were used to compare LSRS publication rates to those of other spine meetings. In addition, impact of published articles was evaluated by average citation count and average journal impact factor. Results: From 2008 to 2012, a total of 332 podium and poster presentations were identified. The overall publication rate was 55.1% (183/332). For podium presentations, this was greatest in 2012 (66.0%) and lowest in 2008 (51.5%). For poster presentations, this was greatest in 2012 (53.6%) and lowest in 2010 (25.0%). The publication rate of presentations is statistically greater than the publication rates of Eurospine (37.8%, P Conclusions: While LSRS is a relatively young society, these findings point to the high quality of presentations at this scientific meeting. These findings speak to the scientific rigor of presentations at LSRS. Clinical Relevance: This study helps clinicians and scientists gauge the quality of a research meeting and make informed choices on which gatherings to attend.

Retrospective cohort comparison study.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.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.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.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%).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 III.

The etiology, complications, and rerevision risks of early aseptic revision total hip arthroplasty (THA) within 90 days are insufficiently documented.A national insurance claims database (PearlDiver Technologies, Fort Wayne, IN) was queried for patients who underwent unilateral aseptic revision THA within 90 days of the index procedure using administrative codes. Patients who underwent revision for infection, without minimum 2-year follow-up, and younger than 18 years were excluded. This cohort was matched based on gender, age, and Charlson Comorbidity Index to a control group of patients who underwent primary THA without revision within 90 days. Two-year rerevision and 90-day complication rates were recorded. Chi-square and Fisher exact tests were used as appropriate for statistical comparison.Four hundred two patients met the inclusion criteria for early aseptic revision within 90 days of the index procedure and were matched to the control group. The overall 2-year rerevision rate was higher in the early revision group compared with control group (14.9% vs 2.5%, P.001). Complications within 90 days occurred more frequently in the early revision group, including blood transfusion (10.2% vs 3.2%, P.001), deep vein thrombosis (9.0% vs 3.2%, P = .001), and pulmonary embolism (2.74% vs 0.75%, P = .031). The most common reasons for early aseptic revision were dislocation (41.5%), fracture (38.1%), and loosening (17.4%).Early aseptic revision THA is associated with significantly higher 90-day complication rates and 2-year rerevision rates compared with a control group of primary THA without revision. The most common reasons for acute early revision were dislocation, fracture, and mechanical loosening.Level III.

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Background Context The presence of missing data is a limitation of large datasets, including the National Surgical Quality Improvement Program (NSQIP). In addressing this issue, most studies use complete case analysis, which excludes cases with missing data, thus potentially introducing selection bias. Multiple imputation, a statistically rigorous approach that approximates missing data and preserves sample size, may be an improvement over complete case analysis. Purpose The present study aims to evaluate the impact of using multiple imputation in comparison with complete case analysis for assessing the associations between preoperative laboratory values and adverse outcomes following anterior cervical discectomy and fusion (ACDF) procedures. Study Design/Setting This is a retrospective review of prospectively collected data. Patient Sample Patients undergoing one-level ACDF were identified in NSQIP 2012–2015. Outcome Measures Perioperative adverse outcome variables assessed included the occurrence of any adverse event, severe adverse events, and hospital readmission. Methods Missing preoperative albumin and hematocrit values were handled using complete case analysis and multiple imputation. These preoperative laboratory levels were then tested for associations with 30-day postoperative outcomes using logistic regression. Results A total of 11,999 patients were included. Of this cohort, 63.5% of patients had missing preoperative albumin and 9.9% had missing preoperative hematocrit. When using complete case analysis, only 4,311 patients were studied. The removed patients were significantly younger, healthier, of a common body mass index, and male. Logistic regression analysis failed to identify either preoperative hypoalbuminemia or preoperative anemia as significantly associated with adverse outcomes. When employing multiple imputation, all 11,999 patients were included. Preoperative hypoalbuminemia was significantly associated with the occurrence of any adverse event and severe adverse events. Preoperative anemia was significantly associated with the occurrence of any adverse event, severe adverse events, and hospital readmission. Conclusions Multiple imputation is a rigorous statistical procedure that is being increasingly used to address missing values in large datasets. Using this technique for ACDF avoided the loss of cases that may have affected the representativeness and power of the study and led to different results than complete case analysis. Multiple imputation should be considered for future spine studies.

The prevalence of dialysis-dependent patients in the United States is growing. Prior studies evaluating the risk of perioperative adverse events for dialysis-dependent patients are either institutional cohort studies limited by patient numbers or administrative database studies limited to inpatient data.The present study uses a large, national sample with 30-day follow-up to investigate dialysis as risk factor for perioperative complications independent of patient demographics or comorbidities.This is a retrospective cohort study.Patients undergoing elective spine surgery with or without dialysis from the 2005-2015 National Surgical Quality Improvement Program (NSQIP) database were included in the study.Postoperative complications within 30 days and binomial reoperation, readmission, and mortality within 30 days were determined.The 2005-2015 NSQIP databases were queried for adult dialysis-dependent and dialysis-independent patients undergoing elective spinal surgery. Differences in 30-day outcomes were compared using risk-adjusted multivariate regression and coarsened exact matching analysis for adverse events, unplanned readmission, reoperation, and mortality. The percentage of complications occurring before versus after hospital discharge was also assessed. The authors have no financial disclosures related to the present study.A total of 467 dialysis and 173,311 non-dialysis patients met the inclusion criteria. Controlling for age, gender, body mass index, functional status, and American Society of Anesthesiologists (ASA) class, dialysis patients were found to be at significantly greater odds of any adverse event (odds ratio [OR]=2.52 before, 2.17 after matching, p=.001), major adverse event (OR=2.90 before, 2.52 after matching, p=.001), and minor adverse event (OR=1.50 before matching, p=.025, but not significantly different after matching). Further, dialysis patients were significantly more likely to return to the operating room (OR=2.77 before, 2.50 after matching, p=.001), have unplanned readmissions (OR=2.73 before, 2.37 after matching, p=.001), and die within 30 days (OR=3.77 before, 2.71 after matching, p=.001). Adverse events occurred after discharge for 51.78% of non-dialysis patients and for 43.80% of dialysis patients.Dialysis patients undergoing elective spine surgery are at significantly higher risk of aggregated adverse outcomes, return to the operating room, readmission, and death than non-dialysis patients, even after controlling for patient demographics and overall health (as indicated by ASA class). These differences need to be considered when determining treatment options. Additionally, with bundled payments expected in spine surgery, physicians and hospitals need to account for increased costs and liabilities when working with dialysis patients.

No known study has compared the predictive power of the American Society of Anesthesiologists (ASA) class, modified Charlson Comorbidity Index, modified Frailty Index, and demographic characteristics for general health complications after total hip arthroplasty (THA).Comorbidity indices and demographics from National Surgical Quality Improvement Program THA patients were evaluated for discriminative ability in predicting adverse outcomes using the area under the curve analysis from the receiver operating characteristic curves. Perioperative outcomes included any adverse event, severe adverse events, minor adverse events, extended hospital stay, and discharge to higher-level care.In total, 64,792 THA patients were identified. The most predictive comorbidity index was ASA, and demographic factor was age. Of these, age had the greatest discriminative ability for four of the five adverse outcomes.For THA, easily obtained patient ASA and age are more predictive of perioperative adverse outcomes than the more complex and numerically tabulated modified Charlson Comorbidity Index and modified Frailty Index.

Background Context Venous thromboembolism (VTE) is a known complication after spine surgery, but prophylaxis guidelines are ambiguous for patients undergoing elective spine surgery. Purpose The objective of this study was to characterize the incidence and risk factors for VTE and the association of pharmacologic prophylaxis with VTE and bleeding complications after elective spine surgery. Study Design/Setting This is a retrospective cohort study of patients undergoing elective spine surgery in the National Surgical Quality Improvement Program (NSQIP) database and a retrospective cohort analysis at an academic medical center. Patient Sample This study included 109,609 patients in the NSQIP database from 2005 to 2014 and 2,855 patients at the authors' institution from January 2013 to March 2016 who underwent elective spine surgery. Outcome Measures The incidence and risk factors for VTE were assessed in both cohorts based on the NSQIP criteria. The incidence of bleeding complications requiring reoperation was assessed based on operative reports in the institutional cohort. Materials and Methods Associations of patient and procedure factors with VTE were characterized in the NSQIP population. In the single-institution cohort, in addition to NSQIP variables, a chart review was completed to determine the use of VTE prophylaxis, the history of prior VTE, and the incidence of hematoma requiring reoperation. The association of patient and procedure variables, including pharmacologic prophylaxis and history of prior VTE, with VTE and hematoma requiring reoperation were determined with multivariate regression. Results Among 109,609 elective spine surgery patients in NSQIP, independent risk factors for VTE were greater age, male gender, increasing body mass index, dependent functional status, lumbar spine surgery, longer operative time, perioperative blood transfusion, longer length of stay, and other postoperative complications. There were 2,855 patients included in the institutional cohort. Pharmacologic prophylaxis was performed in 56.3% of the institutional patients, of whom 97.1% received unfractionated heparin. When controlling for patient and procedural variables, pharmacologic prophylaxis did not significantly influence the rate of VTE, but was associated with a significant increase in hematoma requiring a return to the operating room (relative risk=7.37, p=.048). Conclusions Pharmacologic prophylaxis, primarily with unfractionated heparin, after elective spine surgery was not associated with a significant reduction in VTE. However, there was a significant increase in postoperative hematoma requiring reoperation among patients undergoing prophylaxis. This raises questions about the routine use of unfractionated heparin for VTE prophylaxis and supports the need for further consideration of risks and benefits of chemoprophylaxis after elective spine surgery.

STUDY DESIGN Retrospective cohort study. OBJECTIVE To determine if International Classification of Diseases (ICD) coding for obesity is biased toward certain subgroups and how potential bias may influence the outcomes of database research in spine. SUMMARY OF BACKGROUND DATA There has been increased use of national databases using administrative data in the spine surgery literature. Past research demonstrates that sensitivity of ICD codes for obesity is poor, but it is unknown if such inaccuracies are systematically biased and if they may bias studies utilizing such data. METHODS Patients who underwent elective posterior lumbar fusion, 2013 to 2016, at a large academic hospital were identified. All ICD codes assigned to the encounter were obtained. Body mass index (BMI) was calculated based on height and weight. The sensitivity of ICD coding for obesity was calculated. Sensitivity was compared for subgroups defined by demographic, comorbidity, intraoperative, and postoperative factors. The association of obesity (as defined by BMI≥30 and ICD coding) with 30-day postoperative adverse events was tested with multivariate regression. RESULTS The study included 796 patients. The overall sensitivity of ICD coding for obesity was 42.5%. The sensitivity of ICD coding for obesity was significantly higher in patients with greater BMI, diabetes, American Society of Anesthesiologists class≥III, increased length of stay, venous thromboembolism, any adverse event, and major adverse event. Multivariate analysis for determining outcomes of increased risk with obesity as defined by ICD coding included venous thromboembolism, major adverse events, and any adverse events. However, multivariate analysis for determining outcomes of increased risk with obesity defined by BMI did not yield any positive associations. CONCLUSION ICD codes for obesity are more commonly assigned to patients with other comorbidities or postoperative complications. Further, use of such nonrandomly assigned ICD codes for obesity has the potential to skew studies to suggest greater associated adverse events than calculated BMI would demonstrate. LEVEL OF EVIDENCE 3.

Background The Rothman Index is a comprehensive measure of overall patient status in the inpatient setting already in use at many medical centers. It ranges from 100 (best score) to -91 (worst score) and is calculated based on 26 variables encompassing vital signs, routine laboratory values, and organ system assessments from nursing rounds from the electronic medical record. Past research has shown an association of Rothman Index with complications, readmission, and death in certain populations, but it has not been evaluated in geriatric patients with hip fractures, a potentially vulnerable patient population. Questions/purposes (1) Is there an association between Rothman Index scores and postdischarge adverse events in a population aged 65 years and older with hip fractures? (2) What is the discriminative ability of Rothman Index scores in determining which patients will or will not experience these adverse events? (3) Are there Rothman Index thresholds associated with increased incidence of postdischarge adverse outcomes? Methods One thousand two hundred fourteen patients aged 65 years and older who underwent hip fracture surgery at an academic medical center between 2013 and 2016 were identified. Demographic and comorbidity characteristics were characterized, and 30-day postdischarge adverse events were calculated. The associations between a 10-unit change in Rothman Index scores and postdischarge adverse events, mortality, and readmission were determined. American Society of Anesthesiologists (ASA) class was used as a measure of comorbidity because prior research has shown its performance to be equivalent or superior to that of calculated comorbidity measures in this data set. We assessed the ability of Rothman Index scores to determine which patients experienced adverse events. Finally, Rothman Index thresholds were assessed for an association with increased incidence of postdischarge adverse outcomes. Results We found a strong association between Rothman Index scores and postdischarge adverse events (lowest score: odds ratio [OR] = 1.29 [1.18-1.41], p < 0.001; latest score: OR = 1.37 [1.24-1.52], p < 0.001) after controlling for age, sex, body mass index, ASA class, and surgical procedure performed. The discriminative ability of lowest and latest Rothman Index scores was better than those of age, sex, and ASA class for any adverse event (lowest value: area under the curve [AUC] = 0.641; 95% confidence interval [CI], 0.601-0.681; latest value: AUC = 0.640; 95% CI, 0.600-0.680); age (0.534; 95% CI, 0.493-0.575, p < 0.001 for both), male sex (0.552; 95% CI, 0.518-0.585, p = 0.001 for both), and ASA class (0.578; 95% CI, 0.542-0.614; p = 0.004 for lowest Rothman Index, p = 0.006 for latest Rothman Index). There was never a difference when comparing lowest Rothman Index value and latest Rothman Index value for any of the outcomes (Table 5). Patients experienced increased rates of postdischarge adverse events and mortality with a lowest Rothman Index of ≤ 35 (p < 0.05) or latest Rothman Index of ≤ 55 (p < 0.05). Conclusions The Rothman Index provides an objective method of assessing perioperative risk in the setting of hip fracture surgery in patients older than age 65 years and is more accurate than demographic measures or ASA class. Furthermore, there are Rothman Index thresholds that can be used to identify patients at increased risk of complications. Physicians can use this tool to monitor the condition of patients with hip fracture, recognize patients at high risk of adverse events to consider changing their plan of care, and counsel patients and families. Further investigation is needed to determine whether interventions based on Rothman Index values contribute to improved outcomes or value of hip fracture care. Level of Evidence Level II, diagnostic study.

Study Design.Retrospective cohort comparison study.Objective.To compare perioperative outcomes between navigated and conventional single-level instrumented posterior lumbar fusions in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database.Summary of Backgroun

STUDY DESIGN This is a retrospective study. OBJECTIVE To study the differences in definition of "inpatient" and "outpatient" [stated status vs. actual length of stay (LOS)], and the effect of defining populations based on the different definitions, for anterior cervical discectomy and fusion (ACDF) and lumbar discectomy procedures in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. SUMMARY OF BACKGROUND DATA There has been an overall trend toward performing ACDF and lumbar discectomy in the outpatient setting. However, with the possibility of patients who underwent outpatient surgery staying overnight or longer at the hospital under "observation" status, the distinction of "inpatient" and "outpatient" is not clear. MATERIALS AND METHODS Patients who underwent ACDF or lumbar discectomy in the 2005-2014 ACS-NSQIP database were identified. Outpatient procedures were defined in 1 of 2 ways: either as being termed "outpatient" or hospital LOS=0. Differences in definitions were studied. Further, to evaluate the effect of the different definitions, 30-day outcomes were compared between "inpatient" and "outpatient" and between LOS>0 and LOS=0 for ACDF patients. RESULTS Of the 4123 "outpatient" ACDF patients, 919 had LOS=0, whereas 3204 had LOS>0. Of the 13,210 "inpatient" ACDF patients, 337 had LOS=0, whereas 12,873 had LOS>0. Of the 15,166 "outpatient" lumbar discectomy patients, 8968 had LOS=0, whereas 6198 had LOS>0. Of the 12,705 "inpatient" lumbar discectomy patients, 814 had LOS=0, whereas 11,891 had LOS>0. On multivariate analysis of ACDF patients, when comparing "inpatient" with "outpatient" and "LOS>0" with "LOS=0" there were differences in risks for adverse outcomes based on the definition of outpatient status. CONCLUSIONS When evaluating the ACS-NSQIP population, ACDF and lumbar discectomy procedures recorded as "outpatient" can be misleading and often did not correlate with same day discharge. These findings have significant impact on the interpretation of existing studies and define an area that needs clarification for future studies. LEVEL OF EVIDENCE Level 3.

Background Despite the advantages of large, national datasets, one continuing concern is missing data values. Complete case analysis, where only cases with complete data are analyzed, is commonly used rather than more statistically rigorous approaches such as multiple imputation. This study characterizes the potential selection bias introduced using complete case analysis and compares the results of common regressions using both techniques following unicompartmental knee arthroplasty. Methods Patients undergoing unicompartmental knee arthroplasty were extracted from the 2005 to 2015 National Surgical Quality Improvement Program. As examples, the demographics of patients with and without missing preoperative albumin and hematocrit values were compared. Missing data were then treated with both complete case analysis and multiple imputation (an approach that reproduces the variation and associations that would have been present in a full dataset) and the conclusions of common regressions for adverse outcomes were compared. Results A total of 6117 patients were included, of which 56.7% were missing at least one value. Younger, female, and healthier patients were more likely to have missing preoperative albumin and hematocrit values. The use of complete case analysis removed 3467 patients from the study in comparison with multiple imputation which included all 6117 patients. The 2 methods of handling missing values led to differing associations of low preoperative laboratory values with commonly studied adverse outcomes. Conclusion The use of complete case analysis can introduce selection bias and may lead to different conclusions in comparison with the statistically rigorous multiple imputation approach. Joint surgeons should consider the methods of handling missing values when interpreting arthroplasty research.

BACKGROUND: Patients with geriatric hip fractures may be at increased risk for postoperative Clostridium difficile colitis, which can cause severe morbidity and can influence hospital quality metrics. However, to our knowledge, no large database study has calculated the incidence of, factors associated with, and effect of C. difficile colitis on geriatric patients undergoing hip fracture surgery. QUESTIONS/PURPOSES: To use a large national database with in-hospital and postdischarge data (National Surgical Quality Improvement Program(®) [NSQIP®]) to (1) determine the incidence and timing of C. difficile colitis in geriatric patients who underwent surgery for hip fracture, (2) identify preoperative and postoperative factors associated with the development of C. difficile colitis in these patients, and (3) test for an association between C. difficile colitis and postoperative length of stay, 30-day readmission, and 30-day mortality. PATIENTS AND METHODS: This is a retrospective study. Patients who were 65 years or older who underwent hip fracture surgery were identified in the 2015 NSQIP database. The primary outcome was a diagnosis of C. difficile colitis during the 30-day postoperative period. Preoperative and procedural factors were tested for association with the development of C. difficile colitis through a backward stepwise multivariate model. Perioperative antibiotic type and duration were not included in the model, as this information was not recorded in the NSQIP. The association between C. difficile colitis and postoperative length of stay, 30-day readmission, and 30-day mortality were tested through multivariate regressions, which adjusted for preoperative and procedural characteristics such as age, comorbidities, and surgical procedure. A total of 6928 patients who were 65 years or older and underwent hip fracture surgery were identified. RESULTS: The incidence of postoperative C. difficile colitis was 1.05% (95% CI, 0.81%-1.29%; 73 of 6928 patients). Of patients who had C. difficile colitis develop, 64% (47 of 73 patients) were diagnosed postdischarge and 79% (58 of 73 patients) did not have a preceding infectious diagnosis. Preoperative factors identifiable before surgery that were associated with the development of C. difficile colitis included admission from any type of chronic care facility (versus admitted from home; relative risk [RR] = 1.98; 95% CI, 1.11-3.55; p = 0.027), current smoker within 1 year (RR = 1.95; 95% CI, 1.03-3.69; p = 0.041), and preoperative anemia (RR = 1.76; 95% CI, 1.07-2.92; p = 0.027). Patients who had pneumonia (RR = 2.58; 95% CI, 1.20-5.53; p = 0.015), sepsis (RR = 4.20; 95% CI, 1.27-13.82; p = 0.018), or “any infection” (RR = 2.26; 95% CI, 1.26-4.03; p = 0.006) develop after hip fracture were more likely to have C. difficile colitis develop. Development of C. difficile colitis was associated with greater postoperative length of stay (22 versus 5 days; p < 0.001), 30-day readmission (RR = 3.41; 95% CI, 2.17-5.36; p < 0.001), and 30-day mortality (15% [11 of 73 patients] versus 6% [439 of 6855 patients]; RR = 2.16; 95% CI, 1.22-3.80; p = 0.008). CONCLUSIONS: C. difficile colitis is a serious infection after hip fracture surgery in geriatric patients that is associated with 15% mortality. Patients at high risk, such as those admitted from any type of chronic care facility, those who had preoperative anemia, and current smokers within 1 year, should be targeted with preventative measures. From previous studies, these measures include enforcing strict hand hygiene with soap and water (not alcohol sanitizers) if a provider is caring for patients at high risk and those who are C. difficile-positive. Further, other studies have shown that certain antibiotics, such as fluoroquinolones and cephalosporins, can predispose patients to C. difficile colitis. These medications perhaps should be avoided when prescribing prophylactic antibiotics or managing infections in patients at high risk. Future prospective studies should aim to determine the best prophylactic antibiotic regimens, probiotic formula, and discharge timing that minimize postoperative C. difficile colitis in patients with hip fractures. LEVEL OF EVIDENCE: Level III, therapeutic study.

STUDY DESIGN Retrospective matched cohort study of prospectively collected data. OBJECTIVE To compare rates of adverse events and readmission between lumbar total disc arthroplasty (TDA) and anterior lumbar interbody fusion (ALIF) using the American College of Surgeons National Surgical Quality Improvement Program database. SUMMARY OF BACKGROUND DATA TDA and ALIF may be considered for similar degenerative indications. However, there have been a few large-cohort comparison studies of short-term clinical outcomes for these procedures. METHODS The 2011-2015 NSQIP databases were retrospectively queried to identify patients who underwent elective stand-alone ALIF and TDA. After propensity matching, the association of procedure type with adverse events and readmission was determined using McNemar's test. Operative time and postoperative length of stay (LOS) were compared using multivariate linear regression. Risk factors for adverse events were determined using multivariate Poisson regression. RESULTS In total, 1801 ALIF and 255 TDA patients were identified. After matching with propensity scores, there were no significant differences in the rates of any adverse event, serious adverse events, individual adverse events, or readmission other than blood transfusion, which occurred more frequently in the ALIF cohort (3.92% vs. 0.39%, P = 0.007). Operative time was not significantly different between the two cohorts, but postoperative LOS was significantly longer for ALIF cases (+0.28 days, P < 0.001). When evaluating 10 preoperative variables as potential risk factors for adverse events and readmission after TDA and ALIF, the majority of results were similar. CONCLUSION The only identified differences in perioperative outcomes between TDA and ALIF were a 3.53% higher incidence of blood transfusion and 0.28-day longer LOS for the ALIF group. These results suggest overall similar short-term general-health outcomes between the two groups, and that the choice between the two procedures, for the appropriately selected patient, should be based on longer-term functional outcomes. LEVEL OF EVIDENCE 3.

Purpose The purpose of the current study was to use the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) to determine whether there were differences in 30-day perioperative complications between open arthrotomy and arthroscopy for the treatment of septic knees in a large national sample. Methods Patients who were diagnosed with a septic knee and underwent open arthrotomy or arthroscopy were identified in the 2005-2014 NSQIP data sets. Patient demographics and perioperative complications were characterized and compared between the 2 procedures. Results In total, 168 patients undergoing knee arthrotomy and 216 patients undergoing knee arthroscopy for septic knee were identified. There were no statistically significant differences in demographic variables between the 2 groups. On univariate analysis, the rate of minor adverse events (MAEs; 15.48% vs 8.80%, P = .043) was higher in the open arthrotomy treatment group, while the rate of serious adverse events (SAEs; 37.50% vs 26.19%, P = .019) was higher in the arthroscopic surgery treatment group. On multivariate analysis, which controlled for patient characteristics/comorbidities and used the Bonferroni correction for multiple comparisons, there were no statistically significant differences in risk of any adverse events (relative risk [RR] = 0.851; 99% confidence interval [CI], 0.598-1.211; P = .240), MAE (RR = 1.653; 99% CI, 0.818-3.341; P = .066), SAE (RR = 0.706; 99% CI, 0.471-1.058; P = .027), return to the operating room (RR = 0.810; 99% CI, 0.433-1.516; P = .387), or readmission (RR = 1.022; 99% CI, 0.456-2.294; P = .944) between open compared with arthroscopic surgery. Conclusions Univariate analysis revealed a lower rate of MAE but a higher rate of SAE in the arthroscopic surgery treatment group. However, on multivariate analysis, similar perioperative complications, rate of return to the operating room, and rate of readmission were found after open and arthroscopic debridement for septic knees. Based on the lack of demonstrated superiority of either of these 2 treatment modalities for this given diagnosis, and the expectation that most differences in perioperative complications for this diagnosis would have declared themselves within the first 30 days, deciding between the studied treatment modalities may be based more on other factors not included in this study. Level of Evidence Retrospective comparative study, Level III.

The number of octogenarians undergoing revision total knee arthroplasty (TKA) is increasing. However, there has been a lack of studies investigating the perioperative course and safety of revision TKA performed in this potentially vulnerable population in a large patient population. The purpose of this study is to compare complications following revision TKA between octogenarians and 2 younger patient populations (70 and 70-79 year olds).Patients who underwent revision TKA were identified in the 2005-2015 National Surgical Quality Improvement Program database and stratified into 3 age groups:70, 70-79, and ≥80 years. Baseline preoperative and intraoperative characteristics were compared between the 3 groups. Propensity score matched comparisons were then performed for 30-day perioperative complications, length of hospital stay, and readmissions.This study included 6523 (70 years), 2509 (70-79 years), and 957 octogenarian patients who underwent revision TKA. After propensity matching, statistical analysis revealed only higher rates of blood transfusion and slightly longer length of stay in octogenarians compared to70 year olds. Similarly, octogenarians had only higher rates of blood transfusion and slightly longer length of stay compared to 70-79 year olds. Notably, there were no differences in mortality or readmission between octogenarians compared to younger populations.These data suggest that revision TKA can safely be considered for octogenarians with the observation of higher rates of blood transfusion and slightly longer length of stay compared to younger populations. Octogenarian patients need not be discouraged from revision TKA solely based on their advanced age.

Despite extensive research regarding risk factors for adverse events after total joint arthroplasty (TJA), there are few publications describing the timing at which such adverse events occur. (1) On which postoperative day do certain adverse events occur? (2) What adverse events occur earlier after TKA than after THA? (3) For each adverse event, what proportion occurred after hospital discharge? We screened the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) to identify all patients undergoing primary THA and primary TKA between 2005 and 2013, resulting in a study population of 124,657 patients evaluated as part of this retrospective database analysis. For each of eight different adverse events, the median postoperative day of diagnosis, interquartile range for day of diagnosis, and middle 80% for day of diagnosis were determined. Multivariate Cox proportional hazards modeling was used to test whether there is a difference of timing for each adverse event as stratified by TKA or THA. The proportion of adverse events occurring after versus before discharge was also calculated. The median day of diagnosis (and interquartile range; middle 80%) for stroke was 2 (1–10; 1–19), myocardial infarction 3 (2–6; 1–15), pulmonary embolism 3 (2–7; 1–19), pneumonia 4 (2–9; 2–17), deep vein thrombosis 6 (3–14; 2–23), urinary tract infection 8 (3–16; 2–24), sepsis 10 (5–19; 2–24), and surgical site infection 17 (11–23; 6–28). For the later occurring adverse events (surgical site infection, sepsis), the rate of occurrence remained high at the end of the 30-day postoperative period. Timing was earlier in patients undergoing TKA for pulmonary embolism (day 3 [interquartile range 2–6] versus 5 [3–17], p < 0.001) and deep vein thrombosis (day 5 [2–11] versus 13 [6–22], p < 0.001). The proportion of events occurring after discharge for myocardial infarction was 97 of 283 (34%), stroke 42 of 118 (36%), pulmonary embolism 223 of 625 (36%), pneumonia 171 of 426 (40%), deep vein thrombosis 576 of 956 (60%), urinary tract infection 958 of 1406 (68%), sepsis 284 of 416 (68%), and surgical site infection 1147 of 1212 (95%). As lengths of hospital stay after TJA continue to decrease, our findings suggest that caution is in order because several acute and immediately life-threatening findings, including myocardial infarction and pulmonary embolism, might occur after discharge. Furthermore, the timing of surgical site infection and sepsis suggests that even the 30-day followup afforded by the ACS-NSQIP may not be sufficient to study the latest occurring adverse events. Additionally, both pulmonary embolism and deep vein thrombosis tend to occur earlier after TKA than THA, and this should guide clinical surveillance efforts in patients undergoing those procedures. These findings also indicate that inpatient-only databases (such as the Nationwide Inpatient Sample) may fail to capture a very large proportion of postoperative adverse events, weakening the conclusions of many published studies using those databases. Level III, therapeutic study.

A higher volume of primary total hip arthroplasty (THA) is starting to be performed as an outpatient procedure. However, data on appropriate patient selection for this surgical protocol is scarce.Patients who underwent primary THA were identified in the 2012-2018 National Surgical Quality Improvement Program database. Outpatient procedure was defined as having a hospital length of stay of 0 days. The primary outcome was a readmission within the 30-day postoperative period. Risk factors for and effect of overnight hospital stay on 30-day readmission after outpatient THA were identified through multivariable models. Reasons for and timing of readmission were also identified.A total of 5245 outpatient THA patients and 44,171 patients who stayed 1 night were identified. The incidence of 30-day readmission after outpatient THA was 1.60% (95% confidence interval [CI] 1.26-1.94). Risk factors for 30-day readmission after outpatient THA include the following: older age relative to 18-60 years old (most notably 71-75 years old, relative risk [RR] = 2.3, 95% CI = 1.15-4.62; 76-80 years old, RR = 6.6, 95% CI = 3.55-12.43; and80 years old, RR = 5.6, 95% CI = 2.43-12.89, P.001) and bleeding disorders (RR = 4.5, 95% CI = 1.45-14.31, P = .010). For patients who had some of these risk factors, their risk of medically related 30-day readmission was reduced if they had stayed 1 night at the hospital (P.05). The majority of readmissions were surgically related (62%), including wound complications (27%) and periprosthetic fractures (25%).The rate of 30-day readmission after outpatient THA was low. Patients who are at high risk for 30-day readmission after outpatient THA include those with older age and bleeding disorders. Some of these patients may benefit from an inpatient hospital stay.

Study design Survey study and retrospective review of prospective data. Objectives To contrast surgeons' perceptions and reported national data regarding the rates of postoperative adverse events following anterior cervical discectomy and fusion (ACDF) and to assess the accuracy of surgeons in predicting the impact of patient factors on such outcomes. Methods A survey investigating perceived rates of perioperative complications and the perceived effect of patient risk factors on the occurrence of complications following ACDF was distributed to spine surgeons at the Cervical Spine Research Society (CSRS) 2015 Annual Meeting. The equivalent reported rates of adverse events and impacts of patient risk factors on such complications were assessed in patients undergoing elective ACDF from the National Surgical Quality Improvement Program (NSQIP). Results There were 110 completed surveys from attending physicians at CSRS (response rate = 44%). There were 18 019 patients who met inclusion criteria in NSQIP years 2011 to 2014. The rates of 11 out of 17 (65%) postoperative adverse events were mildly overestimated by surgeons responding to the CSRS questionnaire in comparison to reported NSQIP data (overestimates ranged from 0.24% to 1.50%). The rates of 2 out of 17 (12%) postoperative adverse events were mildly underestimated by surgeons (range = 0.08% to 1.2%). The impacts of 5 out of 10 (50%) patient factors were overestimated by surgeons (range relative risk = 0.56 to 1.48). Conclusions Surgeon estimates of risk factors for and rates of adverse events following ACDF procedures were reasonably nearer to national data. Despite an overall tendency toward overestimation, surgeons' assessments are roughly appropriate for surgical planning, expectation setting, and quality improvement initiatives.

STUDY DESIGN Retrospective cohort study. OBJECTIVE To compare short-term morbidity for primary and revision anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA Revision ACDF procedures are relatively common, yet their risks are poorly characterized in the literature. There is a need to assess the relative risk of revision ACDF procedures compared with primary surgery. METHODS The prospectively collected American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify patients who underwent primary and revision ACDF from 2005 to 2014. The occurrence of 30-day postoperative complications, readmission, operative time, and postoperative length of stay were compared between primary and revision procedures using multivariate regression to control for patient and operative characteristics. RESULTS A total of 20,383 ACDF procedures were identified, 1219 (6.0%) of which were revision cases. On multivariate analysis, revision procedures were associated with significantly increased risk of any adverse event (relative risk [RR] 2.3, P

Background Extensive research has been conducted concerning the epidemiology of fractures of the calcaneus and ankle. However, less work has characterized the population sustaining talus fractures, necessitating the analysis of a large, national sample to assess the presentation of this important injury. Methods The current study included adult patients from the 2011 through 2015 National Trauma Data Bank (NTDB) who had talus fractures. Modified Charlson Comorbidity Index (CCI), mechanism of injury (MOI), Injury Severity Score (ISS), and associated injuries were evaluated. Results Out of 25,615 talus fracture patients, 15,607 (61%) were males. The age distribution showed a general decline in frequency as age increased after a peak incidence at 21 years of age. As expected, CCI increased as age increased. The mechanism of injury analysis showed a decline in motor vehicle accidents (MVAs) and an increase in falls as age increased. ISS was generally higher for MVAs compared to falls and other injuries. Overall, 89% of patients with a talus fracture had an associated injury. Among associated bony injuries, non-talus lower extremity fractures were common, with ankle fractures (noted in 42.7%) and calcaneus fractures (noted in 27.8%) being the most notable. The most common associated internal organ injuries were lung (noted in 19.0%) and intracranial injuries (noted in 14.9%). Conclusion This large cohort of patients with talus fractures defined the demographics of those who sustain this injury and demonstrated ankle and calcaneus fractures to be the most commonly associated injuries. Other associated orthopaedic and non-orthopaedic injuries were also defined. In fact, the incidence of associated lumbar spine fracture was similar to that seen for calcaneus fractures (14%) and nearly 1 in 5 patients had a thoracic organ injury. Clinicians need to maintain a high suspicion for such associated injuries for those who present with talus fractures. Level of Evidence Level II, retrospective study

STUDY DESIGN This was a retrospective study of prospectively collected data. OBJECTIVE To utilize a large national database with prospectively collected data [National Surgical Quality Improvement Program Pediatric (NSQIP-Pediatric)] to study the safety and effectiveness of antifibrinolytic use during multilevel posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA There is currently a lack of consensus and evidence regarding the safety and effectiveness of antifibrinolytic use for pediatric patients undergoing corrective surgery for AIS. MATERIALS AND METHODS Patients who underwent multilevel PSF for AIS in the 2016 NSQIP-Pediatric database were identified. Preoperative and procedural characteristics were compared between patients who received antifibrinolytics versus those who did not. Multivariate regressions were used to compare perioperative transfusion rates and postoperative outcomes, such as rate of return to the operating room, 30-day readmission, and intensive care unit and hospital length of stay between the 2 treatment groups. RESULTS This study included 975 patients who received antifibrinolytics and 223 patients who did not. Patients who received these agents tended to have more levels fused, osteotomies performed, and longer operative times. After controlling for these variances, there were no statistical differences in rate and volume of transfusion, rate of return to the operating room, 30-day readmission, 30-day postoperative complications, or intensive care unit or hospital length of stay between the 2 treatment groups. CONCLUSIONS This study did not demonstrate transfusion reduction in the group that received antifibrinolytics. This finding may be, in part, secondary to nonoptimized or nonstandardized protocols for antifibrinolytic use in pediatric deformity surgery or the inability to adequately control for selection bias, as those with greater surgical invasiveness may be more likely to receive antifibrinolytics. Nonetheless, using antifibrinolytics in this population appears safe and not associated with increased perioperative complications. LEVEL OF EVIDENCE Level III.

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.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.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; P0.001), 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; P0.001), 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; P0.001), and a cardiac complication after discharge was associated with increased 30-day readmission (RR = 12.32; 95% CI = 8.17 to 18.59; P0.001). 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; P0.001).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 III.

Objectives: Upper extremity injuries following motorcycle crashes (MCC) incur increased healthcare costs and rehabilitation needs. We aim to characterize the epidemiology of MCC upper extremity injuries and identify factors that influence the severity of and cost of care for upper extremity injuries. Methods: We performed a retrospective cohort analysis of 571 patients with upper extremity injuries after MCC at a level 1 trauma center from 2002 to 2013. We collected data pertaining to demographics, helmet use, toxicology, bony injury, Injury Severity Score (ISS), Glasgow Coma Scale (GCS), hospital length of stay (LOS), and cost. Continuous variables were compared using t-test or Wilcoxon rank test, depending on data distribution, and dichotomous variables were compared using Pearson’s chi-squared or Fisher’s exact tests. Regression models were used to evaluate the effect of intoxication or helmets on injury location, severity, cost of care, and LOS. Results: The incidence of MCC upper extremity injury was 47.5%, with hand and forearm fractures the most common injuries (25.5% and 24.7% of total injuries). Intoxicated patients were more likely to have a high cost of care (p = 0.012), extended LOS (p = 0.038), plastic surgery involvement in their care (p = 0.038), but fewer upper extremity bony injuries (p = 0.019). Non-helmeted patients sustained less upper extremity bony injuries (p p = 0.001), yet more severe injuries (ISS ≥ 30, p = 0.006 and GCS p Conclusion: Upper extremity injuries are common in motorcyclists. Despite vital protection for the brain and maxillofacial injury, helmeted MCC patients have an increased incidence of upper extremity injuries compared to non-helmeted patients, but overall have less severe injuries. Intoxicated patients have fewer upper extremity bony injuries, but the higher cost of care, and extended LOS. Therefore, even with the increased risk of injury helmets may expose to the upper extremity, helmets reduced overall morbidity and mortality. In addition to mandatory helmet laws, we advocate for further development of safety equipment focusing specifically on the prevention of upper extremity injuries.

Background Prophylactic surgical treatment of the femur is commonly offered to patients with metastatic disease who have a high risk of impending pathologic fracture. Prophylactic fixation is associated with improved functional outcomes in appropriate patients selected based on established criteria, but the perioperative complication profile has received little attention. Given the substantial comorbidity in this population, it is important to characterize surgical risks for surgeons and patients to improve treatment decisions. Questions/purposes (1) What is the incidence of postoperative adverse events after prophylactic surgical stabilization of metastatic lesions of the femoral shaft or distal femur? (2) How does this complication profile compare with stabilization of pathologic fractures adjusted for differences in patient demographics and comorbidity? Methods We performed a retrospective study using the National Surgical Quality Improvement Program (NSQIP) database. We identified patients undergoing prophylactic treatment of the femoral shaft or distal femur by Current Procedural Terminology (CPT) codes. Patients undergoing treatment of a pathologic fracture were identified by CPT code for femur fracture fixation as well as an International Classification of Diseases code indicating neoplasm or pathologic fracture. We tracked adverse events, operative time, blood transfusion, hospital length of stay, and discharge to a facility within 30 days postoperatively. There were 332 patients included in the prophylactic treatment group and 288 patients in the pathologic fracture group. Patients in the prophylactic treatment group presented with greater body mass index (BMI), whereas the pathologic fracture group presented with a greater incidence of disseminated cancer. The odds of experiencing adverse events were initially compared between the two groups using bivariate logistic regression and then using multivariate regression controlling for age, sex, BMI, and American Society of Anesthesiologists (ASA) class and disseminated cancer causing marked physiological compromise per NSQIP guidelines. Results With multivariate analysis controlling for age, sex, BMI, and ASA class, patients with pathologic fracture were more likely to experience any adverse event (odds ratio [OR], 1.53; 95% confidence interval [CI], 1.03-2.29; p = 0.036), major adverse events (OR, 1.61; 95% CI, 1.01-2.55; p = 0.043), death (OR, 1.90; 95% CI, 1.07-3.38; p = 0.030), blood transfusion (OR, 1.57; 95% CI, 1.08-2.27; p = 0.017), and hospital stay ≥ 9 days (OR, 1.51; 95% CI, 1.05-2.19; p = 0.028) compared with patients undergoing prophylactic treatment. However, when additionally controlling for disseminated cancer, the only difference was that patients with pathologic fractures were more likely to receive a blood transfusion than were patients undergoing prophylactic fixation (OR, 1.61; 95% CI, 1.12-2.36; p = 0.011). Conclusions After controlling for differences in patient characteristics, prophylactic treatment of femoral metastases was associated with a decreased likelihood of blood transfusion and no differences in terms of the frequency of other adverse events. In the context of prior studies supporting the mechanical and functional outcomes of prophylactic treatment, the findings of this cohort suggest that the current guidelines have achieved a reasonable balance of morbidity in patients with femoral lesions and further support the current role of prophylactic treatment of impending femur fractures in appropriately selected patients. Level of evidence Level III, therapeutic study.

STUDY DESIGN A retrospective cohort comparison study. OBJECTIVE The aim of this study was to investigate the perioperative adverse event profile of cervical total disc replacement (CTDR) performed as an outpatient relative to inpatient procedure. SUMMARY OF BACKGROUND DATA Recent reimbursement changes and a push for safe reductions in hospital stay have resulted in increased interest in performing CTDRs in the outpatient setting. However, there has been a paucity of studies investigating the safety of outpatient CTDR procedures, despite increasing frequency. METHODS Patients who underwent single-level CTDR were identified in the 2005 to 2016 National Surgical Quality Improvement Program database. Outpatient versus inpatient procedure status was defined by length of stay, with outpatient being less than 1 day. Patient baseline characteristics and comorbidities were compared between the two groups. Propensity score matched comparisons were then performed for 30-day perioperative complications and readmissions between the two cohorts. In addition, perioperative outcomes of outpatient single-level CTDR versus matched outpatient single-level anterior cervical discectomy and fusion (ACDF) cases were compared. RESULTS In total, 373 outpatient and 1612 inpatient single-level CTDR procedures were identified. After propensity score matching was performed to control for potential confounders, statistical analysis revealed no significant difference in perioperative complications between outpatient versus matched inpatient CTDR. Notably, the rate of readmissions was not different between the two groups. In addition, there was no difference in rates of perioperative adverse events between outpatient single-level CTDR versus matched outpatient single-level ACDF. CONCLUSION The perioperative outcomes evaluated in the current study support the conclusion that, for appropriately selected patients, single-level CTDR can be safely performed in the outpatient setting without increased rates of 30-day perioperative complications or readmissions compared with inpatient CTDR or outpatient single-level ACDF. LEVEL OF EVIDENCE 3.

This study uses a prospective surgical registry to characterize the timing of 10 postoperative adverse events following geriatric hip fracture surgery. There were 19,873 patients identified who were ≥70 years undergoing surgery for hip fracture as part of the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP). The median postoperative day of diagnosis (and interquartile range) for myocardial infarction was 3 (1-5), cardiac arrest requiring cardiopulmonary resuscitation 3 (0-8), stroke 3 (1-10), pneumonia 4 (2-10), pulmonary embolism 4 (2-11), urinary tract infection 7 (2-13), deep vein thrombosis 9 (4-16), sepsis 9 (4-18), mortality 11 (6-19), and surgical site infection 16 (11-22). For the earliest diagnosed adverse events, the rate of adverse events had diminished by postoperative day 30. For the later diagnosed adverse events, the rate of adverse events remained high at postoperative day 30. Findings help to enable more targeted clinical surveillance, inform patient counseling, and determine the duration of follow-up required to study specific adverse events effectively. Orthopedic surgeons should have the lowest threshold for testing for each adverse event during the time period of greatest risk.

Aims The aim of this study was to compare the rate of perioperative complications following aseptic revision total hip arthroplasty (THA) in patients aged ≥ 80 years with that in those aged < 80 years, and to identify risk factors for the incidence of serious adverse events in those aged ≥ 80 years using a large validated national database. Patients and Methods Patients who underwent aseptic revision THA were identified in the 2005 to 2015 National Surgical Quality Improvement Program (NSQIP) database and stratified into two age groups: those aged < 80 years and those aged ≥ 80 years. Preoperative and procedural characteristics were compared. Multivariate regression analysis was used to compare the risk of postoperative complications and readmission. Risk factors for the development of a serious adverse event in those aged ≥ 80 years were characterized. Results The study included 7569 patients aged < 80 years and 1419 were aged ≥ 80 years. Multivariate analysis showed a higher risk of perioperative mortality, pneumonia, urinary tract infection and the requirement for a blood transfusion and an extended length of stay in those aged ≥ 80 years compared with those aged < 80 years. Independent risk factors for the development of a serious adverse event in those aged ≥ 80 years include an American Society of Anesthesiologists score of ≥ 3 and procedures performed under general anaesthesia. Conclusion Even after controlling for patient and procedural characteristics, aseptic revision THA is associated with greater risks in patients aged ≥ 80 years compared with younger patients. This is important for counselling and highlights the need for medical optimization in these vulnerable patients. Cite this article: Bone Joint J 2018;100-B:143–51.

Objectives The Charlson comorbidity index (CCI), Elixhauser comorbidity measure (ECM), and modified frailty index (mFI) have been associated with mortality after hip fracture. The present study compares the clinically informative discriminative ability of CCI, ECM, and mFI, as well as demographic characteristics for predicting in-hospital adverse outcomes after surgical management of hip fractures. Methods Patients undergoing hip fracture surgery were selected from the 2013 National Inpatient Sample. The discriminative ability of CCI, ECM, and mFI, as well as demographic factors for adverse outcomes were assessed using the area under the curve analysis from receiver operating characteristic curves. Outcomes included the occurrence of any adverse event, death, severe adverse events, minor adverse events, and extended hospital stay. Results In total, 49,738 patients were included (mean age: 82 years). In comparison with CCI and mFI, ECM had the significantly largest discriminative ability for the occurrence of all outcomes. Among demographic factors, age had the sole or shared the significantly largest discriminative ability for all adverse outcomes except extended hospital stay. The best performing comorbidity index (ECM) outperformed the best performing demographic factor (age) for all outcomes. Conclusion Among both comorbidity indices and demographic factors, the ECM had the best overall discriminative ability for adverse outcomes after surgical management of hip fractures. The use of this index in correctly identifying patients at risk for postoperative complications may help set appropriate patient expectations, assist in optimizing prophylaxis regimens for medical management, and adjust reimbursements. More widespread use of this measure for hip fracture studies may be appropriately considered. Level of evidence Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

A retrospective study of prospectively collected data.The aim of this study was to utilize a large national database with post-hospitalization follow-up data [National Surgical Quality Improvement Program (NSQIP)] to determine the incidence, risk factors, timing, and clinical impact of Clostridium difficile colitis in spine surgery patients.Recent literature has suggested an increased incidence of C. difficile infections. However, there has been a lack of large cohort studies defining the incidence and impact of C. difficile colitis in patients undergoing spine surgery.Patients who underwent spine surgical procedures in the 2015 NSQIP database were identified. The primary outcome was a diagnosis of C. difficile colitis within the 30-day postoperative period. Independent risk factors for development of C. difficile colitis were identified using multivariate regression. Postoperative length of stay and rate of 30-day readmission were compared between patients who did and did not develop C. difficile colitis.A total of 23,981 patients who underwent spine surgical procedures were identified. The incidence of C. difficile colitis was approximately 0.11% [95% confidence interval (95% CI), 0.07-0.16]. Of the cases that developed C. difficile colitis, 70% were diagnosed postdischarge and 88% had not had a pre-existing infection diagnosed. Independent risk factors for the development of C. difficile colitis were combined anterior/posterior lumbar fusion procedures [odds ratio (OR) = 12.29, 95% CI = 2.22-68.13, P = 0.010], greater age (most notably ≥76 years old, OR = 10.31, 95% CI = 3.06-34.76, P 0.001), hypoalbuminemia (OR = 6.40, 95% CI = 2.49-16.43, P 0.001), and anemia (OR = 2.39, 95% CI = 1.13-5.05, P = 0.023). The development of C. difficile colitis was associated with greater length of stay (2.2 vs. 12.5 days; P 0.001) and increased 30-day readmission (OR = 8.21, 95% CI = 3.14-21.45, P 0.001).C. difficile was diagnosed in 0.11% of patients undergoing spine surgery. The majority of these cases occurred after discharge and in patients not having prior infection diagnoses. High-risk patients should be monitored and targeted with preventative interventions accordingly.3.

Retrospective cohort comparison study.To compare perioperative outcomes between navigated and conventional single-level instrumented posterior lumbar fusions in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database.Although multiple studies have investigated the accuracy of pedicle screw placement and radiation exposure with navigation, no study has compared perioperative complications between navigated and conventional posterior lumbar fusion. The potential benefits of navigation include improved accuracy of screw placement and reduced surgeon radiation exposure, but this is balanced by potential operative time and surgical site contamination/infection related to this bulky technology.Patients who underwent navigated or conventional single-level posterior instrumented lumbar fusions were identified in the 2010-2015 NSQIP database. The usage of navigation was characterized. Patient characteristics and comorbidities were compared between the two treatment groups. Propensity score matching was done and comparisons were made for operative time, hospital length of stay, postoperative complications, and 30-day readmissions between the two cohorts.The percentage of navigated cases tended to increase over years studied to approximately 10%. After propensity matching to control potential confounding factors, statistical analysis revealed no significant difference in operative time and for most adverse events including wound infection, return to the operating room, and readmission. There were significantly lower blood transfusions in the navigated cohort (2.84% vs. 7.15%, P 0.001). Patients who underwent navigated surgery also had a shorter mean hospital length of stay (0.2 day difference, P = 0.016).The reduced blood loss and mildly reduced hospital length of stay identified for the navigated cases are probably markers of more minimally invasive surgery in the navigated cohort. The current study could not identify other differences in operative time, wound infection, or return to the operating room/readmission between navigated and conventional single level posterior instrumented lumbar cases.3.

Background Context There has been growing interest in performing posterior lumbar fusions (PLFs) in the outpatient setting to optimize patient satisfaction and reduce cost. Although still done in only a small percentage of cases, this has been more possible because of advances in surgical techniques and anesthesia. However, data on the perioperative course of outpatient compared with inpatient PLF in a large sample size are scarce. Purpose This study aimed to compare perioperative complications between outpatient and inpatient PLF in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. Study Design/Setting A retrospective cohort comparison study was carried out. Patient Sample Patients undergoing PLF with or without interbody fusion from the 2005 to 2015 NSQIP database comprised the sample. Outcome Measures Outcome measures were postoperative complications within 30 days and readmission within 30 days. Methods Patients who underwent PLF with or without interbody fusion were identified in the 2005–2015 NSQIP database. Outpatient procedures were defined as cases that had hospital length of stay (LOS)=0 days, whereas inpatient procedures were defined as LOS=1–30 days. Patient characteristics, comorbidities, and procedural variables (inclusion of interbody fusion, instrumentation, and number of levels fused) were compared between the two cohorts. Propensity score-matched comparisons were then performed for postoperative complications and 30-day readmissions between the two groups. Results The current study included 360 outpatient and 36,610 inpatient PLF cases. After propensity matching to control potential confounding factors, statistical analysis revealed no significant difference in postoperative adverse events other than significantly lower blood transfusions in the outpatient group (2.78% vs. 10.83%, p Conclusions Based on the lack of differences in rates of most perioperative complications and 30-day readmissions between the outpatient and inpatient cohorts, it seems that outpatient PLF may be appropriately considered for select patients. However, extremely careful patient selection should be exercised.

This is the first large-scale study to define the injured population and examine associated injuries for patients with tibial shaft fractures. Patients over 18 years of age in the National Trauma Data Bank (NTDB) who presented with tibial shaft fractures during 2011 and 2012 were identified. Modified Charlson Comorbidity Index (CCI), mechanism of injury (MOI), injury severity score (ISS), and specific associated injuries were described. Multivariate logistic regression was used to identify predictors of mortality.

Background Context The Rothman Index (RI) is a comprehensive rating of overall patient condition in the hospital setting. It is used at many medical centers and calculated based on vital signs, laboratory values, and nursing assessments in the electronic medical record. Previous research has demonstrated an association with adverse events, readmission, and mortality in other fields, but it has not been investigated in spine surgery. Purpose The present study aims to determine the potential utility of the RI as a predictor of adverse events after discharge following elective spine surgery. Study Design/Setting This retrospective cohort study was carried out at a large academic medical center. Patient Sample A total of 2,687 patients who underwent elective spine surgery between 2013 and 2016 were included in the present study. Outcome Measures The occurrence of adverse events and readmission after discharge from the hospital, within postoperative day 30, was determined in the present study. Methods Patient characteristics and 30-day perioperative outcomes were characterized, with events being classified as “major adverse events” or “minor adverse events” using standardized criteria. Rothman Index scores from the hospitalization were analyzed and compared for those who did or did not experience adverse events after discharge. The association of lowest and latest scores on adverse events was determined with multivariate regression, controlling for demographics, comorbidities, surgical procedure, and length of stay. Results Postdischarge adverse events were experienced by 7.1% of patients. The latest and lowest RI values were significantly inversely correlated with any adverse events, major adverse events, minor adverse events and readmissions after controlling for age, gender, body mass index, American Society of Anesthesiologists (ASA) class, surgical site, and hospital length of stay. Rates of readmission and any adverse event consistently had an inverse correlation with lowest and latest RI scores, with patients at increased risk with lowest score below 65 or latest score below 85. Conclusions The RI is a tool that can be used to predict postdischarge adverse events after elective spine surgery that adds value to commonly used indices such as patient demographics and ASA. It is found that this can help physicians identify high-risk patients before discharge and should be able to better inform clinical decisions.

There has been great interest in performing outpatient THA and TKA. Studies have compared such procedures done as outpatients versus inpatients. However, stated “outpatient” status as defined by large national databases such as the National Surgical Quality Improvement Program (NSQIP) may not be a consistent entity, and the actual lengths of stay of those patients categorized as outpatients in NSQIP have not been specifically ascertained and may in fact include some patients who are “observed” for one or more nights. Current regulations in the United States allow these “observed” patients to stay more than one night at the hospital under observation status despite being coded as outpatients. Determining the degree to which this is the case, and what, exactly, “outpatient” means in the NSQIP, may influence the way clinicians read studies from that source and the way hospital systems and policymakers use those data. The purposes of this study were (1) to utilize the NSQIP database to characterize the differences in definition of “inpatient” and “outpatient” (stated status versus actual length of stay [LOS], measured in days) for THA and TKA; and (2) to study the effect of defining populations using different definitions. Patients who underwent THA and TKA in the 2005 to 2014 NSQIP database were identified. Outpatient procedures were defined as either hospital LOS = 0 days in NSQIP or being termed “outpatient” by the hospital. The actual hospital LOS of “outpatients” was characterized. “Outpatients” were considered to have stayed overnight if they had a LOS of 1 day or longer. The effects of the different definitions on 30-day outcomes were evaluated using multivariate analysis while controlling for potential confounding factors. Of 72,651 patients undergoing THA, 529 were identified as “outpatients” but only 63 of these (12%) had a LOS = 0. Of 117,454 patients undergoing TKA, 890 were identified as “outpatients” but only 95 of these (11%) had a LOS = 0. After controlling for potential confounding factors such as gender, body mass index, functional status before surgery, comorbidities, and smoking status, we found “inpatient” THA to be associated with increased risk of any adverse event (relative risk, 2.643, p = 0.002), serious adverse event (relative risk, 2.455, p = 0.011), and readmission (relative risk, 2.775, p = 0.010) compared with “outpatient” THA. However, for the same procedure and controlling for the same factors, patients who had LOS > 0 were not associated with any increased risk compared with patients who had LOS = 0. A similar trend was also found in the TKA cohort. Future THA, TKA, or other investigations on this topic should consistently quantify the term “outpatient” because different definitions, stated status or actual LOS, may lead to different assignments of risk factors for postoperative complications. Accurate data regarding risk factors for complications after total joint arthroplasty are crucial for efforts to reduce length of hospital stay and minimize complications. Level III, therapeutic study.

STUDY DESIGN A retrospective cohort study of prospectively collected data. OBJECTIVE As an initial effort to address readmissions after lumbar discectomy, reasons for hospital readmission are identified and discussed. SUMMARY OF BACKGROUND DATA Lumbar discectomy is a commonly performed procedure. The Affordable Care Act codifies penalties for hospital readmissions. New quality-based reimbursements tied to readmissions call for a better understanding of the causes of readmission after procedures such as lumbar discectomy. METHODS Lumbar discectomies performed in 2012 to 2014 were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Patient demographics, surgical variables, and reasons for readmissions within 30 days were recorded. Pearson chi square was used to compare rates of demographics and surgical variables between readmitted and nonreadmitted patients. Multivariate regression was used to identify risk factors for readmission. RESULTS Of 20,376 lumbar discectomies, 533 patients (2.62%) were readmitted within 30 days of surgery. The most common reasons for readmission were surgical site infections (n = 130, 0.64% of all discectomies, 24.4% of all readmissions), followed by pain issues (n = 89, 0.44%, 16.7%), and thromboembolic events (43, 0.21%, 8.1%). Overall time to readmission was 13.0 ± 8.0 days (mean ± standard deviation). Factors most associated with readmission after lumbar discectomy were higher American Society of Anesthesiologists class (relative risk = 1.49, P