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OBJECTIVE To assess the risk factors associated with deep infection after operative treatment of peritalar fracture dislocations. DESIGN A retrospective study was performed to identify patients who had operative treatment of a peritalar fracture dislocation over an 11-year period (2008-2019). SETTING Level 1 trauma center. PARTICIPANTS Patients were identified by review of all surgical billing that included open reduction of peritalar dislocation. Minimum follow-up for inclusion was 3 months or the outcome of interest. A total of 178 patients were identified and 154 patients met inclusion criteria. MAIN OUTCOME The primary outcome was deep infection, defined as return to the operating room for debridement with positive cultures. RESULTS A total of 19 (12.3%) patients developed a post-operative deep infection. The most common associated fractures were talus (47%), calcaneus (33%), and fibula (9%). The infected group was significantly older (47.2 vs 39.5 years, p=0.03). Patients undergoing operative management for peritalar fracture dislocations with current smoking were found to have significantly higher odds of postoperative deep infection (74 vs 34%, aOR=7.4, 95% CI, 2.3-24.1, p=0.001). There was a significantly higher risk of infection in patients with a Gustilo-Anderson type 3 open fractures (32 vs 12%, aOR=5.7, 95% CI, 1.6-20.3, p=0.007). The infected group had high rates of below knee amputation when compared to the group without infection (47 vs 1%, p< 0.001). CONCLUSION In our retrospective study, risk factors for infection after peritalar fracture dislocation included older age, smoking, and Gustilo-Anderson type 3 open fracture. LEVEL OF EVIDENCE Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

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 cohort study. OBJECTIVE To assess nonresponder biases for the HCAHPS survey following spine surgery. SUMMARY OF BACKGROUND DATA The Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey is a publicly reported patient satisfaction survey. In addition to having the potential of impacting a hospital's reputation, it is directly linked to government reimbursement. However, it is known that a minority of patients return this survey, and it is expected that there are nonresponder biases. METHODS All adult inpatient spine surgery patients at a single institution between January 2013 and August 2017 at a single institution were selected for retrospective analysis. Patient demographics and perioperative outcomes were assessed as potential predictors of not returning HCAHPS surveys. Univariate and multivariate analyses were performed. RESULTS Of 5517 spine surgeries analyzed, 1505 (27.3%) patients returned the HCAHPS survey. Response rate was variable based on patient characteristics (with statistically significant differences based on age, functional status, race, and American Society of Anesthesiologists score) but not variable based on anatomic region of the spine surgery. Multivariate analysis revealed that patients who did not return the HCAHPS survey were more likely to be black/African American (OR = 2.8, P

Venous thromboembolism (VTE) is an uncommon but highly morbid and potentially preventable complication in children. This study aimed to characterize the incidence of, and risk factors for, VTE in children undergoing orthopedic surgery. A retrospective analysis was performed using the 2012 to 2017 American College of Surgeons National Surgical Quality Improvement Program Pediatric (NSQIP-P) database. Patient demographics, comorbidities, operative variables, and perioperative outcomes were compared between patients who did and did not develop a VTE. In total, 81,490 pediatric patients who underwent orthopedic surgery were identified. Of those, the mean±SD age was 9.7±4.8 years, and 50.1% were male. Sixty patients (0.07%) developed a postoperative VTE. On multivariate regression, demographic and surgical variables associated with a VTE were ages 16 to 18 years ( P =.002; compared with ages 11 to 15 years), American Society of Anesthesiologists (ASA) classes III and V ( P =.003; compared with ASA classes I and II), preoperative blood transfusion ( P P P P P P P P Orthopedics . 2022;45(1):31–37.]

Purpose Surgical repair of the Achilles tendon is a common procedure in cases of acute rupture. Open Achilles tendon surgery with a traditional extensile approach is most often performed in the prone position, but this can lead to numerous complications. The mini-open approach for repair in the supine position may avoid the risks of the prone position. The purpose of this study is to compare perioperative outcomes and differences in cost between patients undergoing acute Achilles rupture repair with mini-open approach, incision of approximately 3 cm, in the supine position versus traditional approach in the prone position. Methods Patients who underwent surgical repair of acute Achilles rupture at a single institution were retrospectively identified using Current Procedural Terminology (CPT) code 27650. Complication rates and the total cost charged to the insurance companies of both the supine and prone groups were calculated. Results A total of 80 patients were included for analysis, 26 supine and 54 prone. The difference in average total time in the operating room was statistically significant. The prone position took approximately 15% more time (118.7 minutes) compared to the supine position (100 minutes) (p = 0.001). While not statistically significant, the total cost for the supine group ($19,889) was less than the for the prone group ($21,722) (p = 0.153) Average postoperative pain score, infection rate, dehiscence rate, sepsis rate, and deep vein thrombosis (DVT) rate were also similar between the two groups. No patient in either group experienced re-rupture of the Achilles tendon within the first year of primary repair. Conclusion The mini-open approach in the supine position may be advantageous in the repair of acute Achilles rupture in that it reduces total time in the operating room and total cost while maintaining positive patient outcomes. Prospective clinical studies are warranted to validate these assessments.

STUDY DESIGN Retrospective cohort study OBJECTIVE.: The aim of this study was to investigate how elective spine surgery patient preoperative opioid use (as determined by admission NarxCare narcotics use scores) correlated with 30-day perioperative outcomes and postoperative patient satisfaction. SUMMARY OF BACKGROUND DATA The effect of preoperative narcotics usage on postoperative outcomes and patient satisfaction following spine surgery has been of question. The NarxCare platform analyzes the patients' state Physician Drug Monitoring Program (PDMP) records to assign numerical scores that approximate a patient's overall opioid drug usage. METHODS Elective spine surgery cases performed at a single institution between October 2017 and March 2018 were evaluated. NarxCare narcotics use scores at the time of admission were assessed. Patient characteristics, as well as 30-day adverse events, readmissions, reoperations, and mortality, were abstracted from the medical record. Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey data were also abstracted when available.Cases were binned based on the following ranges of admission NarxCare scores: 0, 1 to 99, 100 to 299, 300 to 499, and 500+. Multivariate logistic regressions were performed to compare the odds of having an adverse events, readmission, reoperation, and mortality between the different narcotics groups. One-way analysis of variance analyses were performed to compare HCAHPS survey response rates and HCAHPS survey results between the different narcotics score groups. RESULTS In total, 346 patients met criteria for inclusion in the study (NarxScore 0: n = 74, 1-99: n = 58, 300-499: n = 117, and 500+: n = 21). Multivariate logistic regressions did not detect statistically significant differential odds of experiencing adverse events, readmission, reoperation, or mortality between the different groups of admissions narcotics scores. Analyses of variance did not detect statistically significant differences in HCAHPS survey response rates, total HCAHPS scores, or HCAHP subgroup scores between the different narcotics score groups. CONCLUSION Although there are many reasons to address preoperative patient narcotic utilization, the present study did not detect perioperative outcome differences or patient satisfaction based on the narcotic use scores as stratified here. LEVEL OF EVIDENCE 3.

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.

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.

Pediatric supracondylar humerus fractures are common and often require surgical intervention by an orthopedic surgeon, who may or may not have pediatric subspecialty training. This study used a large national database to assess for potential differences in perioperative outcomes for pediatric supracondylar humerus fractures treated by pediatric and nonpediatric orthopedists. A retrospective comparative cohort analysis was performed using data from the National Surgical Quality Improvement Project-Pediatric (NSQIP-P) database 2012 to 2017. Patients 1 to 11 years old were assessed. Demographics, comorbidities, and the incidence of adverse outcomes were compared between pediatric and nonpediatric orthopedists using multivariate analysis controlling for patient characteristics. A total of 15,831 patients were included in the study. Of these, 85.2% were treated by pediatric orthopedists and 14.8% were treated by nonpediatric orthopedists. Demographics, comorbidity burden, operative time, and hospital length of stay were not significantly different between the study groups. With multivariate analysis controlling for patient factors, no differences were identified for 30-day adverse events, reoperation, or readmission whether surgery was performed by pediatric or nonpediatric orthopedists. Considering self-selection of surgeons who perform surgery for pediatric supracondylar humerus fractures, no differences in hospital or general outcome metrics were identified based on who performed these procedures. [ Orthopedics . 2021;44(2):e203–e210.]

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.

Aims The aims of this study were to evaluate the incidence of postoperatively restricted weight-bearing and its association with outcome in patients who undergo surgery for a fracture of the hip. Patients and Methods Patient aged > 60 years undergoing surgery for a hip fracture were identified in the 2016 National Surgical Quality Improvement Program (NSQIP) Hip Fracture Targeted Procedure Dataset. Analysis of the effect of restricted weight-bearing on adverse events, delirium, infection, transfusion, length of stay, return to the operating theatre, readmission and mortality within 30 days postoperatively were assessed. Multivariate regression analysis was used to adjust for confounding demographic, comorbid and procedural characteristics. Results Of the 4918 patients who met inclusion criteria, 3668 (63.53%) were allowed to weight-bear as tolerated postoperatively. Controlling for patient and procedural factors, multivariate odds of any adverse event, major adverse event, delirium, infection, transfusion, length of stay ≥ 75th percentile (six days) and mortality within 30 days were all higher in patients with weight-bearing restrictions. Notably, there were no differences for thromboembolic events, return to the operating theatre or readmission within 30 days between the groups. Conclusion Elderly patients with a fracture of the hip with postoperative weight-bearing restrictions have a significantly greater risk of developing most adverse events compared with those who are encouraged to weight-bear as tolerated. These findings emphasize the importance of immediate weight-bearing as tolerated to optimize the outcome in these frail patients; however nearly 25% of surgeons fail to meet this evidence-based guideline. Cite this article: Bone Joint J 2018;100-B:1377–84.

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 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.

Aims The aims of this study were to characterize the frequency of missing data in the National Surgical Quality Improvement Program (NSQIP) database and to determine how missing data can influence the results of studies dealing with elderly patients with a fracture of the hip. Patients and Methods Patients who underwent surgery for a fracture of the hip between 2005 and 2013 were identified from the NSQIP database and the percentage of missing data was noted for demographics, comorbidities and laboratory values. These variables were tested for association with ‘any adverse event’ using multivariate regressions based on common ways of handling missing data. Results A total of 26 066 patients were identified. The rate of missing data was up to 77.9% for many variables. Multivariate regressions comparing three methods of handling missing data found different risk factors for postoperative adverse events. Only seven of 35 identified risk factors (20%) were common to all three analyses. Conclusion Missing data is an important issue in national database studies that researchers must consider when evaluating such investigations. Cite this article: Bone Joint J 2018;100-B:226–32.

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.

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.

BackgroundAlthough less common in adults, venous thromboembolism (VTE) in children is a highly morbid, preventable adverse event. While VTE has been well studied among pediatric hospitalized and trauma patients, limited work has been done to examine postoperative VTE in children undergoing surgery.MethodsUsing data from National Surgical Quality Improvement Project Pediatric database (NSQIP-P) from 2012 to 2016, a retrospective cohort analysis was performed to determine the incidence of, and risk factors for, VTE in children undergoing surgery. Additionally, the relationships between VTE and other postoperative adverse outcomes were evaluated.ResultsOf 361 384 pediatric surgical patients, 378 (0.10%) were identified as experiencing postoperative VTE. After controlling for patient and surgical factors, we found that American Society of Anesthesiologists (ASA) class of II or greater, aged 16–18 years, non-elective surgery, general surgery (compared with several other surgical specialties), cardiothoracic surgery (compared with general surgery) and longer operative time were significantly associated with VTE in pediatric patients (pConclusionIn a large pediatric surgical population, an incidence of postoperative VTE of 0.10% was observed. Defined patient and surgical factors, and perioperative adverse events were found to be associated with such VTE events.

Current literature suggests a correlation between preoperative coagulopathies and postsurgical adverse events (AEs). However, this correlation has not been specifically assessed in the total hip arthroplasty (THA) and the total knee arthroplasty (TKA) populations. Patients who underwent primary THA and TKA with coagulopathy data were identified from the 2011–2015 American College of Surgeons National Surgical Quality Improvement Program database. Coagulopathies studied were low platelets, high partial thromboplastin time (PTT), high international normalized ratio (INR), and other hematological conditions. Univariate and multivariate analyses were conducted to explore the relationship between coagulopathies and 30-day AEs following surgery in these populations. In total, 39,605 THA patients and 67,685 TKA patients were identified. Of these, approximately 16% had a coagulopathy. These patients tended to be older and have a dependent functional status, American Society of Anesthesiologists score of 3 or greater, and diabetes mellitus. In the THA cohort, low platelets, high PTT, high INR, and other hematological conditions were associated with increased odds of any AE, major AEs, and minor AEs. High INR and other hematological conditions were associated with an increased odds of hospital readmission. In the TKA group, low platelets, high INR, and other hematological conditions were associated with increased odds of any AE, major AEs, and minor AEs. High PTT was associated with increased odds of major AEs and readmissions. Presence of a coagulopathy was associated with multiple AEs following both THA and TKA. This shows that special attention should be paid patients with any form of coagulopathy to minimize the potential risk of AEs. [ Orthopedics . 2020;43(4):233–238.]

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.

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.

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.

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

Background Context As research tools, the American Society of Anesthesiologists (ASA) physical status classification system, the modified Charlson Comorbidity Index (mCCI), and the modified Frailty Index (mFI) have been associated with complications following spine procedures. However, with respect to clinical use for various adverse outcomes, no known study has compared the predictive performance of these indices specifically following posterior lumbar fusion (PLF). Purpose This study aimed to compare the discriminative ability of ASA, mCCI, and mFI, as well as demographic factors including age, body mass index, and gender for perioperative adverse outcomes following PLF. Study Design/Setting A retrospective review of prospectively collected data was performed. Patient Sample Patients undergoing elective PLF with or without interbody fusion were extracted from the 2011–2014 American College of Surgeons National Surgical Quality Improvement Program (NSQIP). Outcome Measures Perioperative adverse outcome variables assessed included the occurrence of minor adverse events, severe adverse events, infectious adverse events, any adverse event, extended length of hospital stay, and discharge to higher-level care. Methods Patient comorbidity indices and characteristics were delineated and assessed for discriminative ability in predicting perioperative adverse outcomes using an area under the curve analysis from the receiver operating characteristics curves. Results In total, 16,495 patients were identified who met the inclusion criteria. The most predictive comorbidity index was ASA and demographic factor was age. Of these two factors, age had the larger discriminative ability for three out of the six adverse outcomes and ASA was the most predictive for one out of six adverse outcomes. A combination of the most predictive demographic factor and comorbidity index resulted in improvements in discriminative ability over the individual components for five of the six outcome variables. Conclusion For PLF, easily obtained patient ASA and age have overall similar or better discriminative abilities for perioperative adverse outcomes than numerically tabulated indices that have multiple inputs and are harder to implement in clinical practice.

National databases are increasingly being used for research in spine surgery; however, one limitation of such databases that has received sparse mention is the frequency of missing data. Studies using these databases often do not emphasize the percentage of missing data for each variable used and do not specify how patients with missing data are incorporated into analyses. This study uses the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database to examine whether different treatments of missing data can influence the results of spine studies. (1) What is the frequency of missing data fields for demographics, medical comorbidities, preoperative laboratory values, operating room times, and length of stay recorded in ACS-NSQIP? (2) Using three common approaches to handling missing data, how frequently do those approaches agree in terms of finding particular variables to be associated with adverse events? (3) Do different approaches to handling missing data influence the outcomes and effect sizes of an analysis testing for an association with these variables with occurrence of adverse events? Patients who underwent spine surgery between 2005 and 2013 were identified from the ACS-NSQIP database. A total of 88,471 patients undergoing spine surgery were identified. The most common procedures were anterior cervical discectomy and fusion, lumbar decompression, and lumbar fusion. Demographics, comorbidities, and perioperative laboratory values were tabulated for each patient, and the percent of missing data was noted for each variable. These variables were tested for an association with “any adverse event” using three separate multivariate regressions that used the most common treatments for missing data. In the first regression, patients with any missing data were excluded. In the second regression, missing data were treated as a negative or “reference” value; for continuous variables, the mean of each variable’s reference range was computed and imputed. In the third regression, any variables with > 10% rate of missing data were removed from the regression; among variables with ≤ 10% missing data, individual cases with missing values were excluded. The results of these regressions were compared to determine how the different treatments of missing data could affect the results of spine studies using the ACS-NSQIP database. Of the 88,471 patients, as many as 4441 (5%) had missing elements among demographic data, 69,184 (72%) among comorbidities, 70,892 (80%) among preoperative laboratory values, and 56,551 (64%) among operating room times. Considering the three different treatments of missing data, we found different risk factors for adverse events. Of 44 risk factors found to be associated with adverse events in any analysis, only 15 (34%) of these risk factors were common among the three regressions. The second treatment of missing data (assuming “normal” value) found the most risk factors (40) to be associated with any adverse event, whereas the first treatment (deleting patients with missing data) found the fewest associations at 20. Among the risk factors associated with any adverse event, the 10 with the greatest effect size (odds ratio) by each regression were ranked. Of the 15 variables in the top 10 for any regression, six of these were common among all three lists. Differing treatments of missing data can influence the results of spine studies using the ACS-NSQIP. The current study highlights the importance of considering how such missing data are handled. Until there are better guidelines on the best approaches to handle missing data, investigators should report how missing data were handled to increase the quality and transparency of orthopaedic database research. Readers of large database studies should note whether handling of missing data was addressed and consider potential bias with high rates or unspecified or weak methods for handling missing data.