MR Imaging-Based In Vivo Macrophage Imaging to Monitor Immune Response after Radiofrequency Ablation of the Liver.

PURPOSE: To establish molecular magnetic resonance (MR) imaging instruments for in vivo characterization of the immune response to hepatic radiofrequency (RF) ablation using cell-specific immunoprobes. MATERIALS AND METHODS: Seventy-two C57BL/6 wild-type mice underwent standardized hepatic RF ablation (70 °C for 5 minutes) to generate a coagulation area measuring 6-7 mm in diameter. CD68+ macrophage periablational infiltration was characterized with immunohistochemistry 24 hours, 72 hours, 7 days, and 14 days after ablation (n = 24). Twenty-one mice were subjected to a dose-escalation study with either 10, 15, 30, or 60 mg/kg of rhodamine-labeled superparamagnetic iron oxide nanoparticles (SPIONs) or 2.4, 1.2, or 0.6 mg/kg of gadolinium-160 (160Gd)-labeled CD68 antibody for assessment of the optimal in vivo dose of contrast agent. MR imaging experiments included 9 mice, each receiving 10-mg/kg SPIONs to visualize phagocytes using T2∗-weighted imaging in a horizontal-bore 9.4-T MR imaging scanner, 160Gd-CD68 for T1-weighted MR imaging of macrophages, or 0.1-mmol/kg intravenous gadoterate (control group). Radiological-pathological correlation included Prussian blue staining, rhodamine immunofluorescence, imaging mass cytometry, and immunohistochemistry. RESULTS: RF ablation-induced periablational infiltration (206.92 µm ± 12.2) of CD68+ macrophages peaked at 7 days after ablation (P < .01) compared with the untreated lobe. T2∗-weighted MR imaging with SPION contrast demonstrated curvilinear T2∗ signal in the transitional zone (TZ) (186 µm ± 16.9), corresponsing to Iron Prussian blue staining. T1-weighted MR imaging with 160Gd-CD68 antibody showed curvilinear signal in the TZ (164 µm ± 3.6) corresponding to imaging mass cytometry. CONCLUSIONS: Both SPION-enhanced T2∗-weighted and 160Gd-enhanced T1-weighted MR imaging allow for in vivo monitoring of macrophages after RF ablation, demonstrating the feasibility of this model to investigate local immune responses.

Quantitative Automated Segmentation of Lipiodol Deposits on Cone-Beam CT Imaging Acquired during Transarterial Chemoembolization for Liver Tumors: A Deep Learning Approach.

PURPOSE: To show that a deep learning (DL)-based, automated model for Lipiodol (Guerbet Pharmaceuticals, Paris, France) segmentation on cone-beam computed tomography (CT) after conventional transarterial chemoembolization performs closer to the "ground truth segmentation" than a conventional thresholding-based model. MATERIALS AND METHODS: This post hoc analysis included 36 patients with a diagnosis of hepatocellular carcinoma or other solid liver tumors who underwent conventional transarterial chemoembolization with an intraprocedural cone-beam CT. Semiautomatic segmentation of Lipiodol was obtained. Subsequently, a convolutional U-net model was used to output a binary mask that predicted Lipiodol deposition. A threshold value of signal intensity on cone-beam CT was used to obtain a Lipiodol mask for comparison. The dice similarity coefficient (DSC), mean squared error (MSE), center of mass (CM), and fractional volume ratios for both masks were obtained by comparing them to the ground truth (radiologist-segmented Lipiodol deposits) to obtain accuracy metrics for the 2 masks. These results were used to compare the model versus the threshold technique. RESULTS: For all metrics, the U-net outperformed the threshold technique: DSC (0.65 ± 0.17 vs 0.45 ± 0.22, P < .001) and MSE (125.53 ± 107.36 vs 185.98 ± 93.82, P = .005). The difference between the CM predicted and the actual CM was 15.31 mm ± 14.63 versus 31.34 mm ± 30.24 (P < .001), with lesser distance indicating higher accuracy. The fraction of volume present ([predicted Lipiodol volume]/[ground truth Lipiodol volume]) was 1.22 ± 0.84 versus 2.58 ± 3.52 (P = .048) for the current model's prediction and threshold technique, respectively. CONCLUSIONS: This study showed that a DL framework could detect Lipiodol in cone-beam CT imaging and was capable of outperforming the conventionally used thresholding technique over several metrics. Further optimization will allow for more accurate, quantitative predictions of Lipiodol depositions intraprocedurally.

MR Imaging Biomarkers for the Prediction of Outcome after Radiofrequency Ablation of Hepatocellular Carcinoma: Qualitative and Quantitative Assessments of the Liver Imaging Reporting and Data System and Radiomic Features.

PURPOSE: To assess the Liver Imaging Reporting and Data System (LI-RADS) and radiomic features in pretreatment magnetic resonance (MR) imaging for predicting progression-free survival (PFS) in patients with nodular hepatocellular carcinoma (HCC) treated with radiofrequency (RF) ablation. MATERIAL AND METHODS: Sixty-five therapy-naïve patients with 85 nodular HCC tumors <5 cm in size were included in this Health Insurance Portability and Accountability Act-compliant, institutional review board-approved, retrospective study. All patients underwent RF ablation as first-line treatment and demonstrated complete response on the first follow-up imaging. Gadolinium-enhanced MR imaging biomarkers were analyzed for LI-RADS features by 2 board-certified radiologists or by analysis of nodular and perinodular radiomic features from 3-dimensional segmentations. A radiomic signature was calculated with the most informative features of a least absolute shrinkage and selection operator Cox regression model using leave-one-out cross-validation. The association between both LI-RADS features and radiomic signatures with PFS was assessed via the Kaplan-Meier analysis and a weighted log-rank test. RESULTS: The median PFS was 19 months (95% confidence interval, 16.1-19.4) for a follow-up period of 24 months. Multifocality (P = .033); the appearance of capsular continuity, compared with an absent or discontinuous capsule (P = .012); and a higher radiomic signature based on nodular and perinodular features (P = .030) were associated with poorer PFS in early-stage HCC. The observation size, presence of arterial hyperenhancement, nonperipheral washout, and appearance of an enhancing "capsule" were not associated with PFS (P > .05). CONCLUSIONS: Although multifocal HCC clearly indicates a more aggressive phenotype even in early-stage disease, the continuity of an enhancing capsule and a higher radiomic signature may add value as MR imaging biomarkers for poor PFS in HCC treated with RF ablation.

A Matched Comparison of Postoperative Complications Between Smokers and Nonsmokers Following Open Reduction Internal Fixation of Distal Radius Fractures.

PURPOSE: The purpose of the present study was to identify differences in 30-day adverse events, reoperations, readmissions, and mortality for smokers and nonsmokers who undergo operative treatment for a distal radius fracture. METHODS: The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database was queried for patients who had operatively treated distal radius fractures between 2005 and 2017. Patient characteristics and surgical variables were assessed. Thirty-day outcome data were collected on serious (SAEs) and minor adverse events (MAEs), as well as on infection, return to the operating room, readmission, and mortality. Multivariable logistic analyses with and without propensity-score matching was used to compare outcome measures between the smoker and the nonsmoker cohorts. RESULTS: In total, 16,158 cases were identified, of whom 3,062 were smokers. After 1:1 propensity-score matching, the smoking and nonsmoking cohorts had similar demographic characteristics. Based on the multivariable propensity-matched logistic regression, cases in the smoking group had a significantly higher rate of any adverse event (AAE) (odds ratio [OR], 1.75; 95% confidence interval [95% CI], 1.28-2.38), serious adverse event (SAE) (OR, 1.75; 95% CI, 1.22-2.50), and minor adverse event (MAE) (OR, 1.84; 95% CI, 1.04-3.23). Smokers also had higher rates of infection (OR, 1.73; 95% CI, 1.26-2.39), reoperation (OR, 2.07; 95% CI, 1.13-3.78), and readmission (OR, 1.83; 95% CI, 1.20-2.79). There was no difference in 30-day mortality rate. CONCLUSIONS: Smokers who undergo open reduction internal fixation of distal radius fractures had an increased risk of 30-day perioperative adverse events, even with matching and controlling for demographic characteristics and comorbidity status. This information can be used for patient counseling and may be helpful for treatment/management planning. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.

Perioperative Outcomes of Hemiarthroplasty Versus Total Hip Arthroplasty for Geriatric Hip Fracture: The Importance of Studying Matched Populations.

BACKGROUND: Geriatric femoral neck fracture is a common injury for which hemiarthroplasty (HA) or total hip arthroplasty (THA) may be considered in select patients. As prior database studies comparing these have not used propensity matching, which is a robust statistical method of controlling for potentially confounding variables, unmatched and matched methodologies are contrasted in the present study. METHODS: Patients aged ≥70 years who underwent HA or THA for hip fractures were identified from the 2012-2015 National Surgical Quality Improvement database. Propensity score 1:1 matching was performed. Differences in rates of 30-day postoperative adverse outcomes were compared using multivariate logistic regression for unmatched and matched cohorts. RESULTS: In total, 15,558 patients (14,403 HA and 1155 THA) were evaluated. Although multivariate outcomes for the unmatched populations were different for blood transfusion, mortality, minor adverse events, major adverse events, and reoperation, multivariate outcomes for matched populations only differed for blood transfusion (odds ratio 0.6 for HA vs THA, P < .001). Of note, although readmissions were similar for the two groups, patients undergoing THA had a 5.4% greater rate of perioperative readmission due to dislocation. CONCLUSION: Geriatric patients undergoing HA and THA for hip fracture were compared with and without propensity matching. Once matching was performed, the only differences in outcomes between the two groups were a lower transfusion rate among the HA group and a greater readmission rate due to dislocation among the THA group. This suggests that either procedure can be safely considered if found to be advantageous from a longer-term outcome perspective. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

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.

Abnormally High, as Well as Low, Preoperative Platelet Counts Correlate With Adverse Outcomes and Readmissions After Elective Total Knee Arthroplasty.

BACKGROUND: Laboratory studies are routinely performed as a part of the preoperative workup for a total knee arthroplasty (TKA). The ramifications of abnormal preoperative platelet counts remain uncharacterized in large, multicenter patient populations. METHODS: Patients who underwent elective primary TKA were identified in the 2011-2015 National Surgical Quality Improvement Program database. Risk of 30-day postoperative complications was calculated as a function of preoperative platelet counts. Patients were characterized as having a normal platelet count, abnormally low platelet count, and abnormally high platelet count based on relative risk calculations. Univariate and multivariate analyses were performed to associate abnormal platelet counts with patient demographics, operative variables, 30-day postoperative complications, and readmissions. RESULTS: In total, 140,073 patients who underwent elective TKA were identified. Using the relative risk threshold of 1.5 for any adverse event, abnormally low and abnormally high platelet count thresholds were set at ≤116,000/mL and ≥492,000/mL, respectively. Multivariate analyses revealed low platelet counts to be associated with higher rates of any, major, and minor adverse events and longer length of stay. Analogously, high platelet counts were associated with higher rates of any and minor adverse events and longer length of stay. CONCLUSION: The present study employed a large patient sample size and showed that elective TKA patients with abnormally high, as well as low, platelet counts are at increased risk of postoperative adverse outcomes. Focused attention needs to be paid to TKA patients with preoperative abnormal platelet counts for optimization and postoperative care. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Incidence, Risk Factors, and Impact of Clostridium difficile Colitis Following Primary Total Hip and Knee Arthroplasty.

BACKGROUND: An improved understanding of Clostridium difficile is important as it is used as a measure of hospital quality and is associated with substantial morbidity. This study utilizes the National Surgical Quality Improvement Program to determine the incidence, timing, risk factors, and clinical implications of C difficile colitis in patients undergoing primary total hip or knee arthroplasty (THA or TKA). METHODS: Patients who underwent primary THA or TKA as part of the 2015 National Surgical Quality Improvement Program were identified. The primary outcome was a diagnosis of C difficile colitis within the 30-day postoperative period. Risk factors for the development of C difficile colitis were identified using Poisson multivariate regression. RESULTS: A total of 39,172 patients who underwent primary THA or TKA were identified. The incidence of C difficile colitis was 0.10% (95% confidence interval [CI] 0.07-0.13). Of the cases that developed C difficile colitis, 79% were diagnosed after discharge and 84% had not had a preceding infection diagnosed. Independent preoperative and procedural risk factors for the development of C difficile colitis were greater age (most notably ≥80 years old, relative risk [RR] 5.28, 95% CI 1.65-16.92, P = .008), dependent functional status (RR 4.05, 95% CI 1.44-11.36, P = .008), preoperative anemia (RR 2.52, 95% CI 1.28-4.97, P = .007), hypertension (RR 2.51, 95% CI 1.06-5.98, P = .037), and THA (vs TKA; RR 2.25, 95% CI 1.16-4.36, P = .017). Postoperative infectious risk factors were urinary tract infection (RR 10.66, 95% CI 3.77-30.12, P < .001), sepsis (RR 17.80, 95% CI 3.77-84.00, P < .001), and "any infection" (RR 6.60, 95% CI 2.66-16.34, P < .001). CONCLUSION: High-risk patients identified in this study should be targeted with preventative interventions and have perioperative antibiotics judiciously managed.

Dialysis Patients Undergoing Total Knee Arthroplasty Have Significantly Increased Odds of Perioperative Adverse Events Independent of Demographic and Comorbidity Factors.

BACKGROUND: The prevalence of dialysis-dependent patients is growing, and an increasing number of these patients are being considered for total knee arthroplasty (TKA). Studies assessing the preoperative risk associated with TKA in this population are limited to institutional cohorts with small sample sizes or national inpatient databases that lack follow-up data. METHODS: The 2006-2015 National Surgical Quality Improvement Program databases were queried for adult patients undergoing elective TKA. Differences in 30-day any/severe/minor adverse event, need for reoperation, readmission, and mortality were compared for dialysis-dependent and nondialysis TKA patients using risk-adjusted logistic regression. To account for the smaller number of dialysis patients and variations in study populations, coarsened exact matching was used. The proportion of adverse events that occurred before vs after discharge was also assessed. RESULTS: In total, 250 dialysis-dependent patients and 163,560 nondialysis patients met inclusion criteria. After controlling for patient demographics (age, sex, body mass index, functional status) and overall health (American Society of Anesthesiologists class), matched analysis revealed dialysis-dependent patients to be significantly more likely to experience any adverse event (odds ratio = 2.01; 95% confidence interval [CI], 1.34-3.02; P = .001), severe adverse event (odds ratio = 2.49; 95% CI, 1.61-3.84; P < .001), reoperation (odds ratio = 2.38; 95% CI, 1.19-4.75; P = .014), readmission (odds ratio = 2.32; 95% CI, 1.47-3.66; P = .001), and mortality (odds ratio = 6.71; 95% CI, 2.99-22.50; P = .002). The majority of adverse outcomes occurred postdischarge. CONCLUSION: Independent of patient demographics and overall health (American Society of Anesthesiologists), patients undergoing dialysis before TKA are significantly more likely to experience 30-day adverse outcomes than matched nondialysis cohorts. Preoperative evaluation of bone health status and management of medical treatment are warranted in this fragile population. Cautious surgical planning, patient counseling, and heightened surveillance are necessitated throughout their perioperative period and postoperative recovery plans may need to be different from nondialysis counterparts. Furthermore, hospitals and physicians must take these increased risks into account when working on bundle payment reimbursement strategies and resource allocation. LEVEL OF EVIDENCE: 3.

Evaluation of a Standardized Perioperative Management Protocol in the Adult Hematology Anticoagulation Management Service.

BACKGROUND: In North America, 250,000 patients on vitamin K antagonists require surgical procedures each year. Temporary interruption of oral anticoagulation and perioperative bridging therapy with unfractionated heparin or low-molecular-weight heparin are recommended by the American College of Chest Physicians 2012 for select patients. OBJECTIVES: The study objectives are to evaluate adherence and nonadherence to the Johns Hopkins clinic guidelines for perioperative management of anticoagulation and identify bleeding or thromboembolic events during perioperative management of anticoagulation. METHODS: This is a retrospective study of patients who required perioperative management of anticoagulation for an invasive procedure from May 2009 to March 2014. Individualized perioperative anticoagulation management plans were prospectively developed for each patient according to the standardized Johns Hopkins perioperative bridging recommendations and documented in the medical record. Adherence to these standardized Johns Hopkins clinic guidelines, the incidence of thromboembolic events, and bleeding and adverse events during perioperative management were retrieved from the medical record. RESULTS: In 294 perioperative management cases, there was 1 (0.3%) thromboembolism, 3 (1%) major bleeds, and 21 (7%) minor bleeds. One patient experienced facial swelling after starting enoxaparin. There was no difference in thromboembolic (0 vs 1, P = 1.00), major (1 vs 2, P = 1.00), or minor bleeding (14 vs 7, P = 1.00) events in patients managed by providers who were adherent to guidelines when compared with providers who were nonadherent. CONCLUSION: Our study shows that using a standardized guideline for perioperative management of anticoagulation to inform but not to dictate clinical practice leads to low rates of both thromboembolism and bleeding.

Underweight patients are the highest risk body mass index group for perioperative adverse events following stand-alone anterior lumbar interbody fusion.

BACKGROUND CONTEXT: Prior studies investigating the association between Body Mass Index (BMI) and patient outcomes following spine surgery have had inconsistent conclusions, likely owing to insufficient power, confounding variables, and varying definitions and cutoffs for BMI categories (eg, underweight, overweight, obese, etc.). Further, few studies have considered outcomes among low BMI cohorts. PURPOSE: The current study analyzes how anterior lumbar interbody fusion (ALIF) perioperative outcomes vary along the BMI spectrum, using World Health Organization (WHO) categories of BMI. STUDY DESIGN/SETTING: A retrospective cohort study. PATIENT SAMPLE: Patients undergoing stand-alone one or two-level anterior lumbar interbody fusion (ALIF) found in the 2005-2018 American College of Surgeons National Surgical Quality Improvement Program (NSQIP) databases. OUTCOME MEASURES: Thirty-day adverse events, hospital readmissions, post-operative infections, and mortality. METHODS: Stand-alone one or two-level ALIF surgical cases were identified and extracted from the 2005-2018 National Surgical Quality Improvement Program (NSQIP) database. Posterior cases and those primary diagnoses of trauma, tumor, infection, or emergency presentation were excluded. Patients were then binned into WHO guidelines of BMI. The incidence of adverse outcomes within 30-day post-operation was defined. Odds ratios of adverse outcomes, normalized to the average risk of normal-weight subjects (BMI 18.5-24.9 kg/m3), were calculated. Multivariate analysis was then performed controlling for patient factors. RESULTS: In total, 13,710 ALIF patients were included in the study. Incidence of adverse events was elevated in both the underweight (BMI<18.5 kg/m3) and super morbidly obese (>50 kg/m3), however, multivariate risks for adverse events and postoperative infection were elevated for underweight patients beyond those found in any other BMI category. No effect was noted in these identical variables between normal, overweight, obese class 1, or even obese class 2 patients. Multivariate analysis also found overweight patients to show a slightly protective trend against mortality while the super morbidly obese had elevated odds. CONCLUSIONS: Underweight patients are at greater odds of experiencing postoperative adverse events than normal, overweight, obese class 1, or even obese class 2 patients. The present study identifies underweight patients as an at-risk population that should be given additional consideration by health systems and physicians, as is already done for those on the other side of the BMI spectrum.

Use of Artificial Intelligence in Non-Oncologic Interventional Radiology: Current State and Future Directions.

The future of radiology is disproportionately linked to the applications of artificial intelligence (AI). Recent exponential advancements in AI are already beginning to augment the clinical practice of radiology. Driven by a paucity of review articles in the area, this article aims to discuss applications of AI in non-oncologic IR across procedural planning, execution, and follow-up along with a discussion on the future directions of the field. Applications in vascular imaging, radiomics, touchless software interactions, robotics, natural language processing, post-procedural outcome prediction, device navigation, and image acquisition are included. Familiarity with AI study analysis will help open the current 'black box' of AI research and help bridge the gap between the research laboratory and clinical practice.

Patient Factors and Perioperative Outcomes Affect Hospital Consumer Assessment of Healthcare Providers and Systems Survey Response Rates After Primary Total Hip Replacement.

INTRODUCTION: The Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey is a federally mandated survey that assesses patient satisfaction after hospitalization. It has been noted that a minority of patients actually return the survey. Potential bias in who does and does not respond to the survey (nonresponse bias) after total hip arthroplasty (THA) may affect the survey results. METHODS: All adult patients undergoing inpatient elective primary THA between February 2013 and May 2020 at a single institution were selected for retrospective analysis. After discharge, all had been mailed the HCAHPS survey, and the primary outcome for the current study was survey return. Patient characteristics and 30-day perioperative outcomes were assessed. Univariate and multivariate analyses were performed to determine correlations between the above variables and HCAHPS survey return status. RESULTS: Of 3,310 THA patients analyzed, 1,049 (31.69%) returned the HCAHPS surveys. On multivariate regression analyses, patients who did not return the survey were more likely to have a higher American Society of Anesthesia score (score of three or higher, odds ratio [OR] = 2.27; P < 0.001), be more functionally dependent (OR = 2.69; P = 0.005), or be Black/African American (OR = 3.40; P < 0.001). Similarly, patients who did not return the survey were more likely to have had any adverse event (OR = 1.80; P = 0.012), major adverse event (OR = 2.88; P = 0.007), readmission (OR = 2.13; P < 0.001), be discharged to a place other than home (OR = 1.71; P < 0.001), or stay in the hospital for longer than 3 days (OR = 1.89; P < 0.001). DISCUSSION: After THA, the HCAHPS survey response rate was only 31.69% and completion of the survey correlated with demographic and perioperative variables. These findings suggest that the HCAHPS survey results should be interpreted as a skewed sample of the true surgical patient population. Nonresponse bias is an important factor to consider when evaluating healthcare quality, patient satisfaction survey results, and their effects on federal hospital reimbursement rates.

Hospital Consumer Assessment of Healthcare Providers and Systems survey response rates are significantly affected by patient characteristics and postoperative outcomes for patients undergoing primary total knee arthroplasty.

INTRODUCTION: The Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey measures patients' satisfaction of their hospital experience. A minority of discharged patients return the survey. Underlying bias among who ultimately returns the survey (non-response bias) after total knee arthroplasty (TKA) may affect results of the survey. Thus, the objective of the current study is to assess the relationship between patient characteristics and postoperative outcomes on HCAHPS survey nonresponse. METHODS: All adult patients at a single institution undergoing inpatient, elective, primary TKA between February 2013 and May 2020 were selected for analysis. Following discharge, all patients had been mailed the HCAHPS survey. The primary outcome analyzed in the current study is survey return. Patient characteristics, surgical variables, and 30-day postoperative outcomes were analyzed. Univariate and multivariate analyses were performed to identify factors independently associated with return of the HCAHPS survey. RESULTS: Of 4,804 TKA patients identified, 1,498 (31.22%) returned HCAHPS surveys. On multivariate regression analyses controlling for patient factors, patients who did not return the survey were more likely to have a higher American Society of Anesthesia score (ASA score of 4 or higher, OR = 2.37; P<0.001), and be partially or totally dependent (OR = 2.37; P = 0.037). Similarly, patients who did not return the survey were more likely to have had a readmission (OR = 1.94; P<0.001), be discharged to a place other than home (OR = 1.52; P<0.001), or stay in the hospital for longer than 3 days (OR = 1.43; P = 0.004). DISCUSSION: Following TKA, HCAHPS survey response rate was only 31.22% and completion of the survey was associated with several demographic and postoperative variables. These findings suggest that HCAHPS survey results capture a non-representative fraction of the true TKA patient population. This bias is necessary to consider when using HCAHPS survey results as a metric for quality of healthcare and federal reimbursement rates.

Underweight patients are an often under looked "At risk" population after undergoing posterior cervical spine surgery.

BACKGROUND: Body Mass Index (BMI) is a weight-for-height metric that is used to quantify tissue mass and weight levels. Past studies have mainly focused on the association of high BMI on spine surgery outcomes and shown variable conclusions. Prior results may have varied due to insufficient power or inconsistent categorical separation of BMI groups (e.g. underweight, overweight, or obese). Additionally, few studies have considered outcomes of patients with low BMI. The aim of the current study was to analyze patients along the entirety of the BMI spectrum and to establish specific granular BMI categories for which patients become at risk for complication and mortality following posterior cervical spine surgery. METHODS: Patients undergoing elective posterior cervical spine surgery were abstracted from the 2005-2016 National Surgical Quality Improvement Program (NSQIP) databases. Patients were aggregated into pre-established WHO BMI categories and adverse outcomes were normalized to average risk of normal-weight subjects (BMI 18.5-24.9 kg/m2). Risk-adjusted multivariate regressions were performed controlling for patient demographics and overall health. RESULTS: A total of 16,806 patients met inclusion criteria. Odds for adverse events for underweight patients (BMI < 18.5 kg/m2) were the highest among any category of patients along the BMI spectrum. These patients experienced increased odds of any adverse event (Odds Ratio (OR) = 1.67, p = 0.008, major adverse events (OR=2.08, p = 0.001), post-operative infection (OR = 1.95, p = 0.002), and reoperation (OR = 1.84, p = 0.020). Interestingly, none of the overweight or obese categories were found to be correlated with increased risk of adverse event categories other than super-morbidly obese patients (BMI>50.0 kg/m2) for post-operative infection (OR = 1.54, p = 0.041). CONCLUSIONS: The current study found underweight patients to have the highest risk of adverse events after posterior cervical spine surgery. Increased pre-surgical planning and resource allocation for this population should be considered by physicians and healthcare systems, as is often already done for patients on the other end of the BMI spectrum.

Spine Surgery HCAHPS Patient Satisfaction Survey Results Inversely Correlate with Survey Response Time.

STUDY DESIGN: Retrospective review. OBJECTIVE: The aim of this study was to understand the potential correlation of the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey response time on reported satisfaction following spine surgery hospitalization. SUMMARY OF BACKGROUND DATA: With increasing emphasis on patient satisfaction metrics, such as HCAHPS, hospital reputations, and reimbursements are being affected by the results of such surveys. HCAHPS is a 32-question survey about patient experience in the hospital and after discharge. METHODS: HCAHPS surveys were routinely sent to all patients admitted after spine surgery at an academic medical center between January 2013 and August 2017. Survey data, survey return time, patient demographics, and 30-day postoperative outcomes were gathered for all spine surgery patients who returned the survey. Multivariate regression analysis controlling for age, sex, BMI, functional status, American Society of Anesthesiologists class, education, and race was used to determine whether there were differences in rates of "Top Box" response between different time ranges of survey return. RESULTS: In total, 1495 consecutive spinal surgery patients who returned their HCAHPS survey were identified. Of these, 31.51% returned their surveys within 21 days, 48.09% returned them between 22 to 42 days, 13.58% returned them between 43 to 64 days, and 6.82% returned them ≥65 days after distribution. Multivariate regression demonstrated no statistical differences in reported satisfaction between surveys returned between days 0 to 21 and days 22 to 42. However, there were significantly lower scores reported by surveys returned on days 43 to 64 and 65 plus days. CONCLUSION: Centers for Medicare and Medicaid Services only considers HCAHPS surveys returned within the first 42 days. It appears that the survey responses are similar over this time period. Beyond this time, lower scores are reported. Further attention to this less satisfied, later HCAHPS survey returning group seems warranted.Level of Evidence: 2.

Underweight Patients Are the Greatest Risk Body Mass Index Group for 30-Day Perioperative Adverse Events After Total Shoulder Arthroplasty.

INTRODUCTION: Existing literature investigating the correlation of body mass index (BMI) with surgical complications has focused on those with elevated BMI. These investigations have reported mixed conclusions, possible because of insufficient power, poor controlling of confounding variables, and inconsistent definitions of BMI categories (eg, underweight, overweight, and varying classifications of obese). Few studies have considered complications of patients with low BMI. The aim of the current study was to analyze the spectrum of categories for BMI with 30-day perioperative adverse events after primary total shoulder arthroplasty (TSA) to better assess where along the BMI spectrum patients are at risk for complications. METHODS: Patients undergoing elective TSA were abstracted from the National Surgical Quality Improvement Program (NSQIP) databases from 2005 to 2016. Patients were then aggregated into BMI categories, and 30-day adverse events were normalized to average risk of normal-weight subjects (BMI 18.5 to 24.9 kg/m2). Risk-adjusted multivariate regressions were performed, controlling for demographic variables and overall health. RESULTS: In total, 15,717 patients met the inclusion criteria. Underweight TSA patients (BMI < 18.5 kg/m2) had the greatest odds for multiple perioperative adverse events compared with any other BMI category. By multivariate analysis, underweight patients were more likely to experience any adverse event (odds ratio [OR] = 2.22, P = 0.034), serious adverse events (OR = 3.18, P = 0.004), or have postoperative infections (OR = 2.77, P = 0.012) within 30 days when compared with normal-weight patients. No significant difference was observed in these complications for elevated BMI categories when compared with normal-weight patients. CONCLUSIONS: Only underweight TSA patients were found to have higher rates of 30-day perioperative adverse events than normal BMI patients, unlike any overweight/obese category including the super morbidly obese. Underweight TSA patients were thus identified as an at-risk subpopulation of TSA patients who had not previously been described. Physicians and healthcare systems should give additional consideration to this fragile cohort because they often already do for those at the other end of the BMI spectrum. LEVEL OF EVIDENCE: III.

Cement Augmentation of Vertebral Compression Fractures May Be Safely Considered in the Very Elderly.

OBJECTIVE: The objective of the current study was to perform a retrospective review of a national database to assess the safety of cement augmentation for vertebral compression fractures in geriatric populations in varying age categories. METHODS: The 2005-2016 National Surgical Quality Improvement Program databases were queried to identify patients undergoing kyphoplasty or vertebroplasty in the following age categories: 60-69, 70-79, 80-89, and 90+ years old. Demographic variables, comorbidity status, procedure type, provider specialty, inpatient/outpatient status, number of procedure levels, and periprocedure complications were compared between age categories using chi-square analysis. Multivariate logistic regressions controlling for patient and procedural variables were then performed to assess the relative periprocedure risks of adverse outcomes of patients in the different age categories relative to those who were 60-69 years old. RESULTS: For the 60-69, 70-79, 80-89, and 90+ years old cohorts, 486, 822, 937, and 215 patients were identified, respectively. After controlling for patient and procedural variables, 30-day any adverse events, serious adverse events, reoperation, readmission, and mortality were not different for the respective age categories. Cases in the 80- to 89-year-old cohort were at increased risk of minor adverse events compared to cases in the 60- to 69-year-old cohort. CONCLUSION: As the population ages, cement augmentation is being considered as a treatment for vertebral compression fractures in increasingly older patients. These results suggest that even the very elderly may be appropriately considered for these procedures (level of evidence: 3).