Preoperative laboratory testing for total hip arthroplasty: Unnecessary tests or a helpful prognosticator.

BACKGROUND: 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). METHODS: 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. RESULTS: 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. CONCLUSIONS: 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. STUDY DESIGN: Clinical, Level III.

What Is the Adverse Event Profile After Prophylactic Treatment of Femoral Shaft or Distal Femur Metastases?

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.

The Rothman Index Is Associated With Postdischarge Adverse Events After Hip Fracture Surgery in Geriatric Patients.

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.

Discriminative Ability of Elixhauser's Comorbidity Measure is Superior to Other Comorbidity Scores for Inpatient Adverse Outcomes After Total Hip Arthroplasty.

BACKGROUND: Identifying patients at highest risk for a complex perioperative course following total hip arthroplasty (THA) is more important than ever in order to educate patients, optimize outcomes, and to minimize cost and length of stay. There are no known studies comparing the clinically relevant discriminative ability of 3 commonly used comorbidity indices for adverse outcomes following THA: Elixhauser Comorbidity Measure (ECM), the Charlson Comorbidity Index (CCI), and the modified Frailty Index (mFI). METHODS: Patients undergoing THA were extracted from the 2013 National Inpatient Sample. The discriminative ability of ECM, CCI, and mFI, as well as the demographic factors age, body mass index, and gender for the occurrence of index admission Centers for Medicare & Medicaid Services procedure-specific complication measures, extended length of hospital stay, and discharge to a facility were assessed using the area under the curve analysis from receiver operating characteristic curves. RESULTS: ECM outperformed CCI and mFI for the occurrence of all 5 adverse outcomes. Age outperformed gender and obesity for the occurrence of all 5 adverse outcomes. ECM (the best performing comorbidity index) outperformed age (the best performing demographic factor) in discriminative ability for the occurrence of 3 of 5 adverse outcomes. CONCLUSION: The less commonly used ECM outperformed the more often utilized CCI and newer mFI as well as demographic factors in correctly preoperatively identifying patients' probabilities of experiencing an adverse outcome suggesting that wider adoption of ECM should be considered in both identifying likelihoods of adverse patient outcomes and for research purposes in future studies.

Treatments of Missing Values in Large National Data Affect Conclusions: The Impact of Multiple Imputation on Arthroplasty Research.

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.

Definitional Differences of 'Outpatient' Versus 'Inpatient' THA and TKA Can Affect Study Outcomes.

BACKGROUND: 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. QUESTIONS/PURPOSES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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 OF EVIDENCE: Level III, therapeutic study.

Results of Database Studies in Spine Surgery Can Be Influenced by Missing Data.

BACKGROUND: 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. QUESTIONS/PURPOSES: (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? METHODS: 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. RESULTS: 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. CONCLUSIONS: 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. CLINICAL RELEVANCE: 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.

Risk Factors for Venous Thromboembolism in Children Undergoing Orthopedic Surgery.

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<.001), arthrotomy (P<.001), and femur fracture (P<.001). Postoperative adverse events occurring prior to a VTE were also assessed. Controlling for patient factors, independent risk factors for VTE included any adverse event (P<.001), major adverse events (P<.001), minor adverse events (P<.001), reoperation (P<.001), and readmission (P<.001). This study identified an incidence of VTE of 0.07% in a population of more than 80,000 children undergoing orthopedic surgery. The identification of risk factors for VTE in this patient population raises the issue of VTE prophylaxis for select high-risk subpopulations. [Orthopedics. 2022;45(1):31-37.].

Pediatric Supracondylar Humerus Fracture Outcomes by Pediatric and Nonpediatric Orthopedists.

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.].

Coagulopathies Are a Risk Factor for Adverse Events Following Total Hip and Total Knee Arthroplasty.

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.].

Characteristics and Predictors of HCAHPS Nonresponse After Spine Surgery.

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 < 0.001), have a higher American Society of Anesthesiologists score (OR 1.76, P < 0.001), and have had a major adverse event (OR = 1.66; P = 0.001), minor adverse event (OR = 2.50; P < 0.001), discharged to a destination other than home (OR = 2.16, P < 0.001), hospital readmission (OR = 2.58; P < 0.001), and a long hospital length of stay (OR = 1.28, P = 0.001). CONCLUSION: For spine surgery patients, patient characteristics and perioperative outcomes were found to be significantly associated with the nonresponder bias for HCAHPS surveys. Although the potential resultant bias in HCAHPS scores cannot be directly determined, this must be considered in interpreting the results of such satisfaction surveys given that less than one-third of patients actually completed this survey in the study population. LEVEL OF EVIDENCE: 3.

Incidence and considerations of 90-day readmissions following posterior lumbar fusion.

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.

Admission NarxCare Narcotics Scores are not Associated With Adverse Surgical Outcomes or Self-reported Patient Satisfaction Following Elective Spine Surgery.

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.

Management of Degenerative Spondylolisthesis: Analysis of a Questionnaire Study, Correlation With a National Sample, and Perioperative Outcomes of Treatment Options.

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.

Evaluating the effect of growing patient numbers and changing data elements in the National Surgical Quality Improvement Program (NSQIP) database over the years: a study of posterior lumbar fusion outcomes.

BACKGROUND CONTEXT: The use of national databases in spinal surgery outcomes research is increasing. A number of variables collected by the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) changed between 2010 and 2011, coinciding with a rapid increase in the number of patients included per year. However, there has been limited study evaluating the effect that these changes may have on the results of outcomes studies. PURPOSE: The present study aimed to investigate the influence of changing data elements and growth of the NSQIP database on results of lumbar fusion outcomes studies. STUDY DESIGN/SETTING: This is a retrospective cohort study of prospectively collected data. PATIENT SAMPLE: The NSQIP database was retrospectively queried to identify 19,755 patients who underwent elective posterior lumbar fusion surgery with or without interbody fusion between 2005 and 2014. Patients were split into two groups based on year of surgery: 2,802 from 2005 to 2010 and 16,953 from 2011 to 2014. OUTCOME MEASURES: The occurrence of adverse events after discharge from the hospital, within postoperative day 30, was determined. METHODS: Preoperative characteristics and 30-day perioperative outcomes were compared between the era groups using bivariate analysis. To illustrate the effect of such changing data elements, the association between age and postoperative outcomes in the era groups was analyzed using multivariate Poisson regression. The present study had no funding sources, and there were no study-related conflicts of interest for any authors. RESULTS: There were significant differences between the era groups for a variety of preoperative characteristics. Postoperative events such blood transfusion and deep vein thrombosis were also significantly different between the era groups. For the 2005-2010 cohort, age was significantly associated with septic shock by multivariate analysis. For the 2011-2014 cohort, age was significantly associated with septic shock, urinary tract infection, blood transfusion, myocardial infarction, and extended length of stay. CONCLUSIONS: The NSQIP database has undergone substantial changes between 2005 and 2014. These changes may contribute to different results in analyses, such as the association between age and postoperative outcomes, when using older versus newer data. Conclusions from early studies using this database may warrant reconsideration.

Longer Operative Time Is Associated With Increased Adverse Events After Anterior Cervical Diskectomy and Fusion: 15-Minute Intervals Matter.

Little is known about the impact of operative time, as an independent and interval variable, on general health perioperative outcomes following anterior cervical diskectomy and fusion. Therefore, patients undergoing a 1-level anterior cervical diskectomy and fusion were identified in the American College of Surgeons National Surgical Quality Improvement Program. Operative time (as an interval variable) was tested for association with perioperative outcomes using a multivariate regression that was adjusted for differences in baseline characteristics. A total of 15,241 patients were included. Increased surgical duration was consistently correlated with a rise in any adverse event postoperatively, with each additional 15 minutes of operating time raising the risk for having any adverse event by an average of 10% (99.64% confidence interval, 3%-17%, P<.001). In fact, 15-minute increases in surgical duration were associated with incremental increases in the rates of venous thromboembolism, sepsis, unplanned intubation, extended length of hospital stay, and hospital readmission. Greater operative time, despite controlling for other patient variables, increases the risk for overall postoperative adverse events and multiple individual adverse outcomes. This increased risk may be attributed to anesthetic effects, physiologic stresses, and surgical site issues. Although it is difficult to fully isolate operative time as an independent variable because it may be closely related to the complexity of the surgical pathology being addressed, the current study suggests that surgeons should maximize operative efficiency as possible (potentially using strategies that have been shown to improve operative time in the 15-minute magnitude), without compromising the technical components of the procedure. [Orthopedics. 2018; 41(4):e483-e488.].

Systematic Changes in the National Surgical Quality Improvement Program Database Over the Years Can Affect Comorbidity Indices Such as the Modified Frailty Index and Modified Charlson Comorbidity Index for Lumbar Fusion Studies.

STUDY DESIGN: Retrospective cohort study of prospectively collected data. OBJECTIVE: The aim of this study was to investigate the influence of changes in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database over the years on the calculation of the modified Frailty Index (mFI) and the modified Charlson Comorbidity Index (mCCI) for posterior lumbar fusion studies. SUMMARY OF BACKGROUND DATA: Multiple studies have utilized the mFI and/or mCCI and showed them to be predictors of adverse postoperative outcomes. However, changes in the NSQIP database have resulted in definition changes and/or missing data for many of the variables included in these indices. No studies have assessed the influence of different methods of treating missing values when calculating these indices on such studies. METHODS: Elective posterior lumbar fusions were identified in NSQIP from 2005 to 2014. The mFI was calculated for each patient using three methods: treating conditions for which data was missing as not present, dropping patients with missing values, and normalizing by dividing the raw score by the number of variables collected. The mCCI was calculated by the first two of these methods. Mean American Society of Anesthesiologists (ASA) scores used for comparison. RESULTS: In total, 19,755 patients were identified. Mean ASA score increased between 2005 and 2014 from 2.27 to 2.50 (+10.1%). For each of the methods of data handling noted above, mean mFI over the years studied increased by 33.3%, could not be calculated, and increased by 183.3%, respectively. Mean mCCI increased by 31.2% and could not be calculated respectively. CONCLUSION: Systematic changes in the NSQIP database have resulted in missing data for many of the variables included in the mFI and the mCCI and may affect studies utilizing these indices. These changes can be understood in the context of ASA trends, and raise questions regarding the use of these indices with data available in later NSQIP years. LEVEL OF EVIDENCE: 3.

Inaccuracies in ICD Coding for Obesity Would Be Expected to Bias Administrative Database Spine Studies Toward Overestimating the Impact of Obesity on Perioperative Adverse Outcomes.

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.

General Health Adverse Events Within 30 Days Following Anterior Cervical Discectomy and Fusion in US Patients: A Comparison of Spine Surgeons' Perceptions and Reported Data for Rates and Risk Factors.

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.

Adverse Events Following Posterior Lumbar Fusion: A Comparison of Spine Surgeons Perceptions and Reported Data for Rates and Risk Factors.

BACKGROUND: Postoperative complications and risks factors for adverse events play an important role in both decision making and patient expectation setting. The present study serves to contrast surgeons' perceived and reported rates of postoperative adverse events following posterior lumbar fusion (PLF) and to assess the accuracy of predicting the impact of patient factors on such outcomes. METHODS: A survey investigating perceived rates of adverse events and the impact of patient risk factors on them following PLF for degenerative conditions was distributed to spine surgeons at the Lumbar Spine Research Society (LSRS) 2016 annual meeting. For comparison, the corresponding rates and patient risk factors were assessed in patients undergoing elective PLF from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) data years 2011-2014. RESULTS: From the survey, there were 53 responses (response rate of 79%) from attending physicians at LSRS. From NSQIP, there were 16,589 patients who met the inclusion criteria. Adverse event rates estimated by the surgeons at LSRS were close to those determined by NSQIP data (no greater than 2.81% different). The largest differences were for deep vein thrombosis (overestimation of 2.81%, P < .001), anemia requiring transfusion (overestimation of 2.47%, P = .018), and urinary tract infection (overestimation of 2.29%, P < .001). Similarly, the estimated impact of patient factors was similar to the data (within relative risk of 2.02). The largest differences were for current smoking (overestimation of 2.02 relative risk, P < .001), insulin dependent diabetes (overestimation of 1.36, P < .001), and obesity (overestimation of 1.35, P < .001). CONCLUSIONS: The current study noted that surgeon estimates were relatively close to national numbers for estimating the adverse events and impact of patient factors on such outcomes after PLF for degenerative conditions. The estimates are roughly appropriate with a bias toward overestimation for planning and expectation setting.