Safety and Effectiveness of Abre Self-Expanding Venous Stent for Treatment of Superior Vena Cava Syndrome.

PURPOSE: Superior vena cava (SVC) syndrome is a constellation of symptoms that results from partial or complete SVC obstruction. Endovascular SVC stenting is an effective treatment for SVC syndrome with rapid clinical efficacy and low risk of complications. In this study, we assess the technical and clinical outcomes of a cohort of patients with SVC syndrome treated with the AbreTM self-expanding venous stent (Medtronic, Inc, Minneapolis, MN, USA). METHODS: An institutional database was used to retrospectively identify patients with SVC syndrome treated with AbreTM venous self-expanding stent placement between 2021-2023. Patient demographic data, technical outcomes, treatment effectiveness, and adverse events were obtained from the electronic medical record. Nineteen patients (mean age 58.6) were included in the study. Thirteen interventions were performed for malignant compression of the SVC, 5 for central venous catheter-related SVC stenosis, and 1 for HD fistula-related SVC stenosis refractory to angioplasty. RESULTS: Primary patency was achieved in 93% of patients (17/19). Two patients (7%) required re-intervention with thrombolysis and angioplasty within 30 days post-stenting. Mean duration of clinical and imaging follow-up were 228.7 ± 52.7 and 258.7 ± 62.1 days, respectively. All patients with clinical follow-up experienced significant improvement in clinical symptoms post-intervention. No stent related complications were identified post-intervention. CONCLUSIONS: Treatment of SVC syndrome with the AbreTM self-expanding venous stent has high rates of technical and clinical success. No complications related to stent placement were identified in this study.

The Natural History of Splenic Artery Aneurysms: Factors That Predict Aneurysm Growth.

PURPOSE: To examine the natural history of splenic artery aneurysms (SAAs) at a single institution and assess the effect of patient factors and aneurysm characteristics on aneurysm growth. MATERIALS AND METHODS: This single-center retrospective study included patients with SAAs who underwent serial imaging over 30 years (1990-2020). Data regarding patient demographics and aneurysm characteristics were collected. The variables contributing to aneurysm growth were assessed using nonparametric tests for continuous variables and chi-square test for categorical variables. Multivariable linear regression was performed using aneurysm growth rate as a continuous dependent variable. RESULTS: A total of 132 patients were included in this study. The median maximum diameter of the SAAs was 15.8 mm (range, 4.0-50.0 mm). Growth over time was observed in 39% of the aneurysms, whereas the remaining 61% were stable in size. Of aneurysms that increased in size, the median aneurysm growth rate was 0.60 mm/y (range, 0.03-5.00 mm/y). Maximum aneurysm diameter of >2 cm and the presence of >50% mural thrombus were significant positive predictors for aneurysm growth (P = .020 and P = .022, respectively). Greater than 50% rim calcification was a significant negative predictor for aneurysm growth (P = .009) in multivariate analysis. CONCLUSIONS: A larger baseline SAA size, presence of mural thrombus, and lack of rim calcification are associated with increased aneurysm growth rate.

Trends in coronary calcium score and coronary CT angiography imaging volume during the COVID-19 pandemic.

OBJECTIVES: The COVID-19 pandemic disrupted the delivery of preventative care and management of acute diseases. This study assesses the effect of the COVID-19 pandemic on coronary calcium score and coronary CT angiography imaging volume. MATERIALS AND METHODS: A single institution retrospective review of consecutive patients presenting for coronary calcium score or coronary CT angiography examinations between January 1, 2020 to January 4, 2022 was performed. The weekly volume of calcium score and coronary CT angiogram exams were compared. RESULTS: In total, 1,817 coronary calcium score CT and 5,895 coronary CT angiogram examinations were performed. The average weekly volume of coronary CTA and coronary calcium score CT exams decreased by up to 83% and 100%, respectively, during the COVID-19 peak period compared to baseline (P < 0.0001). The post-COVID recovery through 2020 saw weekly coronary CTA volumes rebound to 86% of baseline (P = 0.024), while coronary calcium score CT volumes remained muted at only a 53% recovery (P < 0.001). In 2021, coronary CTA imaging eclipsed pre-COVID rates (P = 0.012), however coronary calcium score CT volume only reached 67% of baseline (P < 0.001). CONCLUSIONS: A significant decrease in both coronary CTA and coronary calcium score CT volume occurred during the peak-COVID-19 period. In 2020 and 2021, coronary CTA imaging eventually superseded baseline rates, while coronary calcium score CT volumes only reached two thirds of baseline. These findings highlight the importance of resumption of screening exams and should prompt clinicians to be aware of potential undertreatment of patients with coronary artery disease.

Preoperative embolization in surgical treatment of spinal metastases originating from non-hypervascular primary tumors: a propensity score matched study using 495 patients.

BACKGROUND CONTEXT: Preoperative embolization (PE) reduces intraoperative blood loss during surgery for spinal metastases of hypervascular primary tumors such as thyroid and renal cell tumors. However, most spinal metastases originate from primary breast, prostate, and lung tumors and it remains unclear whether these and other spinal metastases benefit from PE. PURPOSE: To assess the (1) efficacy of PE on the amount of intraoperative blood loss and safety in patients with spinal metastases originating from non-hypervascular primary tumors, and (2) secondary outcomes including perioperative allogeneic blood transfusion, anesthesia time, hospitalization, postoperative complication within 30 days, reoperation, 90-day mortality, and 1-year mortality. STUDY DESIGN: Retrospective propensity-score matched, case-control study at 2 academic tertiary medical centers. PATIENT SAMPLE: Patients 18 years of age or older undergoing surgery for spinal metastases originating from primary non-thyroid, non-renal cell, and non-hepatocellular tumors between January 1, 2002 and December 31, 2016 were included. OUTCOME MEASURES: The primary outcomes were estimated amount of intraoperative blood loss and complications attributable to PE, such as neurologic injury, wound infection, thrombosis, or dissection. The secondary outcomes included perioperative allogeneic blood transfusion, anesthesia time, hospitalization, postoperative complication within 30 days, reoperation, 90-day mortality, and 1-year mortality. METHODS: In total, 495 patients were identified, of which 54 (11%) underwent PE. After propensity score matching on 21 variables, including primary tumor, number of spinal levels, and surgical treatment, 53 non-PE patients were matched to 53 PE patients. Matching was adequate measured by comparing the matched variables, testing the standardized mean differences (<0.25), and inspecting Kernel density plots. The degree of embolization was noted to be complete, until stasis, or successful in 43 (80%) patients. RESULTS: Intraoperative blood loss did not differ between both groups with a median blood loss in liters of 0.6 (IQR, 0.4-1.2) for non-PE patients and 0.9 (IQR, 0.6-1.2) for PE patients (p=.32). No complications occurred during embolization or the time between embolization and surgery. No differences were found in terms of the secondary outcomes. CONCLUSIONS: Our data suggest that, although no complications occurred and the embolization procedure can be considered safe, patients with non-hypervascular spinal metastases might not benefit from PE. A larger, prospective study could confirm or refute these study findings and aid in elucidating a subset of spinal metastases that might benefit from PE.

Imaging Findings in Immunotherapy-related Renal Toxicity.

Immunotherapy-related adverse events (irAEs) associated with immune-checkpoint inhibitors can affect nearly any organ system including commonly the luminal gastrointestinal tract, hepatobiliary system, lungs, endocrine glands, and skin, many of which have described imaging manifestations. In patients without clinically suspected irAEs, imaging findings may be the first indication of an abnormality that prompts further workup to facilitate early detection and initiation of appropriate treatment, such as therapy discontinuation or corticosteroid therapy. While some irAEs have well described imaging correlates, such as pneumonitis, hypophysitis, and colitis, others are not well described, such as nephritis. We report 2 cases of irAE nephritis associated with PD-1 inhibitor therapy and their imaging features.

Insulin-Dependent Status Influences Post-Procedural Outcomes in Diabetic Patients Following Lower Extremity Endovascular Intervention for Peripheral Arterial Disease.

PURPOSE: Diabetic patients are at increased risk of developing lower extremity peripheral arterial disease (PAD) requiring revascularization. This study assessed the effect of insulin dependence in diabetics on post-procedural outcomes following infra-inguinal endovascular intervention. MATERIALS AND METHODS: The American College of Surgeon's National Surgical Quality Improvement Program database was used to identify 8022 patients undergoing infra-inguinal endovascular interventions between 2014 and 2017. Thirty-day post-procedural outcomes for patients without diabetes, with non-insulin-dependent diabetes mellitus (NIDDM), and with insulin-dependent diabetes mellitus (IDDM) were compared. RESULTS: At presentation, IDDM patients were more likely to present with critical limb ischemia compared to NIDDM and non-diabetic patients. In propensity score-weighted logistic regression analysis, IDDM status was an independent predictor for increased renal complication (odds ratio [OR] = 3.08, confidence interval [CI] = 1.44-6.65), sepsis (OR = 1.68, CI = 1.13-2.48), wound complication (OR = 1.57, CI = 1.09-2.25, p = 0.006), UTI (OR = 2.07, CI = 1.09-3.94, p = 0.03), and readmission (OR = 1.21, CI = 1.03-1.42). NIDDM status was an independent predictor for increased risk of renal complications (OR = 2.80, CI = 1.18-6.63). CONCLUSIONS: IDDM status is an independent predictor for increased risk of 30-day post-procedural complications and readmission compared to both NIDDM and non-diabetic status in patients undergoing lower extremity endovascular interventions for PAD.

Albumin and the fibrinogen-to-albumin ratio: Biomarkers for the acute phase response following total knee arthroplasty.

PURPOSE: Complications following total knee arthroplasty (TKA) lead to patient morbidity and cost. While acute phase reactants, such as c-reactive protein (CRP) and fibrinogen, have been used to predict complications following TKA, the extent and duration of changes in albumin levels following TKA are unknown. It is hypothesized that like CRP and fibrinogen, albumin, and the fibrinogen/albumin ratio (FAR) represent useful measures of the acute phase response (APR) following TKA. The purpose of this study was to describe the longitudinal course of albumin and FAR in healthy patients following TKA, relative to established biomarkers, and examine if the variance in albumin or FAR correlates with patient comorbidities. METHODS: This retrospective cohort study of patients undergoing TKA at a tertiary medical center. CRP, fibrinogen, and albumin values were collected pre- and post-operatively. An age-adjusted Charlson comorbidity index (CCI) was utilized as a measure of patient comorbidity status. RESULTS: The median preoperative albumin value was 4.3 g/dL, which dropped to 3.6 g/dL on postoperative day 1 following TKA. The albumin value returned to 93% of the baseline by postoperative week 2. The course of albumin inversely mirrored the course of CRP (r = -0.41). Median preoperative FAR was 0.087 g/L, which rose to 0.130 g/L by postoperative week 2 and returned to baseline by postoperative week 6. While preoperative FAR strongly correlated with postoperative week 2 values (r = 0.74), there was a weak positive correlation between age-adjusted CCI and pre-operative FAR (r = 0.24) in patients undergoing primary TKA. CONCLUSION: Albumin levels follow a predictable postoperative decline that inversely correlates with CRP in healthy patients following TKA. Given the low cost and abundance of laboratories offering albumin levels, direct albumin levels and/or albumin ratios such as FAR may be underutilized biomarkers for monitoring the APR following TKA.

Utilization of a Virtual Information Session to Increase Engagement With Prospective Applicants in the Setting of COVID-19.

PURPOSE: This study aimed to assess the efficacy of a virtual information session hosted by a diagnostic radiology residency program at addressing applicant concerns about the 2020-2021 interview cycle and highlighting key aspects of the residency program. METHODS: Participants were recruited to attend the virtual information session over a 2-week period via social media and communication with medical school radiology interest groups. Attendees were able to submit questions or topics of interest prior to the session. The virtual information session was hosted by trainees and faculty from a radiology residency. Data regarding the demographics of the attendees and the efficacy of the session were obtained through interactive live polling during the virtual session and a voluntary anonymous postsession survey. RESULTS: A total of 171 attendees participated in the virtual information session. Of the attendees, 42% learned about the session from Twitter and 72% were fourth-year medical students applying for residency. Among topics addressed during the session, attendees indicated that they were most interested in learning about "Application strategies during COVID-19" during an in-session poll. On the post-session survey, 96% of attendees reported being more knowledgeable about the residency program culture and the breadth of research and educational opportunities. CONCLUSION: Given the virtual nature of the 2020-2021 residency application cycle, utilization of web-based platforms for recruitment will be essential. Virtual information sessions can be effective at providing insight into aspects of a residency program that are typically gained during the in-person interview experience.

Factors influencing cumulative radiation dose from percutaneous intra-abdominal abscess drainage in the setting of inflammatory bowel disease.

PURPOSE: Patients with inflammatory bowel disease (IBD) are at risk for intra-abdominal abscesses requiring CT-guided drainage. These patients are at baseline risk of high cumulative radiation exposure from imaging, which may be exacerbated by CT-guided drainage. This study aimed to determine the radiation dose associated with percutaneous drainage in the setting of IBD and identify risk factors associated with high exposure. METHODS: An IRB-approved single-center retrospective study was performed to identify patients with IBD who underwent percutaneous abscess drainage over a 5-year period. An episode of drainage was defined from drain placement to removal, with all intervening procedures and diagnostic CT scans included in the cumulative radiation dose. RESULTS: The mean cumulative effective dose for a drainage episode was 47.50 mSv. The mean duration of a drainage episode was 68.7 days. Patients with a cumulative dose greater than 50 mSv required higher number of follow-up visits compared to patients with less than 50 mSv (6.9 vs. 3.5, p = 0.003*). Patients with higher cumulative dose were also more likely to require drain upsize (54% vs. 13%, p = 0.01*) or additional drain placement (63% vs 24%, p = 0.03*) compared to patients with lower dose. CONCLUSION: Intra-abdominal abscess drainage may be associated with significant cumulative radiation exposure. Requirement of drain upsizing or additional drain placement were associated with higher cumulative radiation dose, which may be related to more severe underlying inflammatory bowel disease.

Comparison of Safety and Efficacy of Percutaneous Microwave Ablation of Central Versus Peripheral Renal Cell Carcinoma.

PURPOSE: Thermal ablation of central renal cell carcinoma has been associated with increased risk of incomplete tumor necrosis and adverse events due to the proximity of tumors to the central collecting system and hilar vessels. The purpose of this study was to compare the safety and efficacy of computed tomography-guided percutaneous microwave ablation of central versus peripheral renal cell carcinoma. MATERIALS AND METHODS: An institutional database was used to retrospectively identify 114 patients with renal cell carcinoma who were treated with computed tomography-guided percutaneous microwave ablation between January 2015 and December 2019. Patients were divided into two cohorts based on tumor location: central versus peripheral. Central renal tumors were defined as being within 4 mm of renal pelvis and/or ureter and peripheral tumors were defined as tumors beyond 4 mm the renal pelvis and/or ureter. Patient demographics, tumor type, technical success, primary technique efficacy and adverse events were recorded from the medical record. Technical success, primary technique efficacy and adverse events were compared between the two cohorts. RESULTS: There were 44 patients in the central group and 70 patients in the peripheral group. Technical success was 100% for both groups. There was no significant difference in primary technique efficacy rates for peripheral compared to central tumors (93% vs. 89%, p = 0.49). There was no significant difference in overall adverse event rate (17.7% vs. 11.7%, p = 0.34) or Grade II or higher adverse event rate (7.8% vs. 2.6%, p = 0.17) following microwave ablation of central versus peripheral lesions. Adjunctive maneuvers of hydrodissection and/or pyeloperfusion were performed significantly more frequently for treatment for central tumors compared to peripheral tumors (53% vs. 29%, p = 0.006). CONCLUSION: When adjunctive procedures were utilized more frequently for central compared to peripheral tumors, there was no significant difference in primary technique efficacy or adverse event rate following CT-guided percutaneous microwave ablation of central compared to peripheral renal cell carcinoma. The data suggest that MWA can be successfully applied to select central renal masses and adjunctive maneuvers such as pyeloperfusion should be strongly considered for patient safety. LEVEL OF EVIDENCE III: Non-randomized controlled cohort study/follow-up study.

A Clinical Prediction Algorithm to Stratify Pediatric Musculoskeletal Infection by Severity.

OBJECTIVE: There are currently no algorithms for early stratification of pediatric musculoskeletal infection (MSKI) severity that are applicable to all types of tissue involvement. In this study, the authors sought to develop a clinical prediction algorithm that accurately stratifies infection severity based on clinical and laboratory data at presentation to the emergency department. METHODS: An IRB-approved retrospective review was conducted to identify patients aged 0 to 18 who presented to the pediatric emergency department at a tertiary care children's hospital with concern for acute MSKI over a 5-year period (2008 to 2013). Qualifying records were reviewed to obtain clinical and laboratory data and to classify in-hospital outcomes using a 3-tiered severity stratification system. Ordinal regression was used to estimate risk for each outcome. Candidate predictors included age, temperature, respiratory rate, heart rate, C-reactive protein (CRP), and peripheral white blood cell count. We fit fully specified (all predictors) and reduced models (retaining predictors with a P-value ≤0.2). Discriminatory power of the models was assessed using the concordance (c)-index. RESULTS: Of the 273 identified children, 191 (70%) met inclusion criteria. Median age was 5.8 years. Outcomes included 47 (25%) children with inflammation only, 41 (21%) with local infection, and 103 (54%) with disseminated infection. Both the full and reduced models accurately demonstrated excellent performance (full model c-index 0.83; 95% confidence interval, 0.79-0.88; reduced model 0.83; 95% confidence interval, 0.78-0.87). Model fit was also similar, indicating preference for the reduced model. Variables in this model included CRP, pulse, temperature, and an interaction term for pulse and temperature. The odds of a more severe outcome increased by 30% for every 10 U increase in CRP. CONCLUSIONS: Clinical and laboratory data obtained in the emergency department may be used to accurately differentiate pediatric MSKI severity. The predictive algorithm in this study stratifies pediatric MSKI severity at presentation irrespective of tissue involvement and anatomic diagnosis. Prospective studies are needed to validate model performance and clinical utility. LEVEL OF EVIDENCE: Level II-prognostic study.

Effects of Antibiotic Timing on Culture Results and Clinical Outcomes in Pediatric Musculoskeletal Infection.

INTRODUCTION: Musculoskeletal infection (MSI) is a common cause of morbidity and hospital resource utilization in the pediatric population. Many physicians prefer to withhold antibiotics until tissue cultures can be taken in an effort to improve culture yields. However, there is little evidence that this practice improves culture results or outcomes in pediatric MSI. Therefore, investigating the effects of antibiotic timing may lead to improved clinical practice guidelines for treating children with MSI. METHODS: An IRB-approved retrospective review was conducted that identified 113 patients aged 0 to 18 who presented to the pediatric emergency room at a tertiary care children's hospital with MSI from 2008 to 2013. Demographic data, culture results, severity markers, and intervention timing were obtained from the medical record. Logistic regression and Cox survival analysis were performed to determine the relationship of antibiotic timing with culture sensitivity and time to discharge. RESULTS: No difference was seen in culture sensitivity antibiotic administration in either the local (55% culture before antibiotics vs. 89% after antibiotics) or disseminated group (76% before vs. 79% after), which persisted when further accounting for disease severity with C-reactive protein. However, later administration of antibiotics in the local infection group correlated with a decreased likelihood of discharge (3.91 d when cultured before antibiotics vs. 2.93 d when cultured after antibiotics; hazard ratio, 0.53; P<0.05). In patients with disseminated infection, antibiotic administration was not shown to correlate with any difference in time to discharge (hazard ratio, 1.08). CONCLUSIONS: The authors were surprised to find that tissue culture sensitivities were not decreased by antibiotic administration in either local or disseminated MSI, suggesting that antibiotic administration should not be delayed to obtain tissue cultures. The correlation of earlier antibiotic administration with shorter length of stay in children with local MSI led the authors to conclude that antibiotics should be initiated as quickly as possible. Further study is necessary to confirm these findings and establish clinical practice guidelines. LEVEL OF EVIDENCE: Level III-retrospective cohort.

C-Reactive Protein Predicts Risk of Venous Thromboembolism in Pediatric Musculoskeletal Infection.

BACKGROUND: The rate of venous thromboembolism in children with musculoskeletal infections (MSKIs) is markedly elevated compared with hospitalized children in general. Predictive biomarkers to identify high-risk patients are needed to prevent the significant morbidity and rare mortality associated with thrombotic complications. We hypothesize that overactivation of the acute phase response is associated with the development of pathologic thrombi and we aim to determine whether elevations in C-reactive protein (CRP) are associated with increased rates of thrombosis in pediatric patients with MSKI. METHODS: A retrospective cohort study measuring CRP in pediatric MSKI patients with or without thrombotic complications. RESULTS: The magnitude and duration of elevation in CRP values correlated with the severity of infection and the development of pathologic thrombosis. In multivariable logistic regression, every 20 mg/L increase in peak CRP was associated with a 29% increased risk of thrombosis (P<0.001). Peak and total CRP were strong predictors of thrombosis with area under the receiver-operator curves of 0.90 and 0.92, respectively. CONCLUSIONS: Future prospective studies are warranted to further define the discriminatory power of CRP in predicting infection-provoked thrombosis. Pharmacologic prophylaxis and increased surveillance should be strongly considered in patients with MSKI, particularly those with disseminated disease and marked elevation of CRP. LEVEL OF EVIDENCE: Level III.

A Novel Classification System Based on Dissemination of Musculoskeletal Infection is Predictive of Hospital Outcomes.

BACKGROUND: Musculoskeletal infections (MSKIs) are a common cause of pediatric hospitalization. Children affected by MSKI have highly variable hospital courses, which seem to depend on infection severity. Early stratification of infection severity would therefore help to maximize resource utilization and improve patient care. Currently, MSKIs are classified according to primary diagnoses such as osteomyelitis, pyomyositis, etc. These diagnoses, however, do not often occur in isolation and may differ widely in severity. On the basis of this, the authors propose a severity classification system that differentiates patients based on total infection burden and degree of dissemination. METHODS: The authors developed a classification system with operational definitions for MSKI severity based on the degree of dissemination. The operational definitions were applied retrospectively to a cohort of 202 pediatric patients with MSKI from a tertiary care children's hospital over a 5-year period (2008 to 2013). Hospital outcomes data [length of stay (LOS), number of surgeries, positive blood cultures, duration of antibiotics, intensive care unit LOS, number of days with fever, and number of imaging studies] were collected from the electronic medical record and compared between groups. RESULTS: Patients with greater infection dissemination were more likely to have worse hospital outcomes for LOS, number of surgeries performed, number of positive blood cultures, duration of antibiotics, intensive care unit LOS, number of days with fever, and number of imaging studies performed. Peak C-reactive protein, erythrocyte sedimentation rate, white blood cell count, and temperature were also higher in patients with more disseminated infection. CONCLUSIONS: The severity classification system for pediatric MSKI defined in this study correlates with hospital outcomes and markers of inflammatory response. The advantage of this classification system is that it is applicable to different types of MSKI and represents a potentially complementary system to the previous practice of differentiating MSKI based on primary diagnosis. Early identification of disease severity in children with MSKI has the potential to enhance hospital outcomes through more efficient resource utilization and improved patient care. LEVEL OF EVIDENCE: Level II-prognostic study.

Similar Clinical Severity and Outcomes for Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus Pediatric Musculoskeletal Infections.

BACKGROUND: Prior studies of pediatric musculoskeletal infection have suggested that methicillin-resistant Staphylococcus aureus (MRSA) infections result in worse outcomes compared with infections with methicillin-susceptible S aureus (MSSA) strains. Based on these results, clinical prediction algorithms have been developed to differentiate between MRSA and MSSA early in a patient's clinical course. This study compares hospital outcomes for pediatric patients with MRSA and MSSA musculoskeletal infection presenting to the emergency department at a large tertiary care children's hospital. METHODS: A retrospective study identified pediatric patients with S aureus musculoskeletal infection over a 5-year period (2008-2013) by sequential review of all pediatric orthopedic consults. Relevant demographic information, laboratory values, and clinical outcomes were obtained from the electronic medical record. RESULTS: Of the 91 identified cases of S aureus pediatric musculoskeletal infection, there were 49 cases of MRSA infection (53%) and 42 cases of MSSA infection (47%). There were no significant differences between MRSA and MSSA infections in median hospital length of stay (4.8 vs 5.7 days, P = .50), febrile days (0.0 vs 1.5 days, P = .10), and antibiotic duration (28 vs 34 days, P = .18). Methicillin-resistant S aureus infections were more likely to require operative intervention than MSSA infection (85% vs 62%, P = .15). A logistic regression model based on C-reactive protein, temperature, white blood cell count, pulse, and respiratory rate at presentation demonstrated poor ability to differentiate between MRSA and MSSA infection. CONCLUSIONS: The results demonstrated no significant differences between MSSA and MRSA musculoskeletal infections for most hospital outcomes measured. However, MRSA infections required more operative interventions than MSSA infections. In addition, a predictive model based on severity markers obtained at presentation was unable to effectively differentiate between MRSA and MSSA infection. The clinical utility and capacity for early differentiation of MRSA and MSSA depends on virulence patterns that may vary temporally and geographically.

Characterizing the Acute Phase Response in Healthy Patients Following Total Joint Arthroplasty: Predictable and Consistent.

BACKGROUND: During surgery, trauma to musculoskeletal tissue induces a systemic reaction known as the acute phase response (APR). When excessive or prolonged, the APR has been implicated as an underlying cause of surgical complications. The purpose of this study was to determine the typical APR following total joint arthroplasty in a healthy population defined by the Charlson Comorbidity Index (CCI). METHODS: This retrospective study identified 180 healthy patients (CCI < 2) who underwent total joint arthroplasty by a single surgeon for primary osteoarthritis from 2013 to 2015. Serial measurements of C-reactive protein (CRP) and fibrinogen were obtained preoperative, perioperative, and at 2 and 6 weeks postoperative. RESULTS: Postoperative CRP peaked during the inpatient period and returned to baseline by 2 weeks. Fibrinogen peaked after CRP and returned to baseline by 6 weeks. Elevated preoperative CRP correlated with a more robust postoperative APR for both total hip arthroplasty and total knee arthroplasty, suggesting that a patient's preoperative inflammatory state correlates with the magnitude of the postoperative APR. CONCLUSION: Measurement of preoperative acute phase reactants may provide an objective means to predict a patient's risk of postoperative dysregulation of the APR and complications.

Pediatric Musculoskeletal Infection: Hijacking the Acute-Phase Response.

Tissue injury activates the acute-phase response mediated by the liver, which promotes coagulation, immunity, and tissue regeneration. To survive and disseminate, musculoskeletal pathogens express virulence factors that modulate and hijack this response. As the acute-phase reactants required by these pathogens are most abundant in damaged tissue, these infections are predisposed to occur in tissues following traumatic or surgical injury. Staphylococcus aureus expresses the virulence factors coagulase and von Willebrand binding protein to stimulate coagulation and to form a fibrin abscess that protects it from host immune-cell phagocytosis. After the staphylococcal abscess community reaches quorum, which is the colony density that enables cell-to-cell communication and coordinated gene expression, subsequent expression of staphylokinase stimulates activation of fibrinolysis, which ruptures the abscess wall and results in bacterial dissemination. Unlike Staphylococcus aureus, Streptococcus pyogenes expresses streptokinase and other virulence factors to activate fibrinolysis and to rapidly disseminate throughout the body, causing diseases such as necrotizing fasciitis. Understanding the virulence strategies of musculoskeletal pathogens will help to guide clinical diagnosis and decision-making through monitoring of acute-phase markers such as C-reactive protein, erythrocyte sedimentation rate, and fibrinogen.

Elevated d-Dimer Is Not Predictive of Symptomatic Deep Venous Thrombosis After Total Joint Arthroplasty.

BACKGROUND: Serum d-dimer is a common screening test for symptomatic deep venous thrombosis (DVT) after total joint arthroplasty. This study characterized the longitudinal resolution of d-dimer measurements after total hip and knee arthroplasty (THA/TKA) over a 6-week period. The authors hypothesized that serum d-dimer would not return to baseline or be below the institutional threshold for a positive test at 6 weeks after uncomplicated total joint arthroplasty, suggesting that quantitative d-dimer has limited clinical utility for postoperative DVT screening. METHODS: An institutional review board-approved retrospective cohort study was conducted with consecutive patients between January 2013 and June 2015. A total of 177 adult patients aged 40-88 years who underwent a primary hip or knee arthroplasty with a Charlson Comorbidity Index <3 were included in the study. Serum d-dimer was measured at preoperative, perioperative, and postoperative 2- and 6-week time points. RESULTS: d-dimer measurements peaked 2 weeks postoperatively for both TKA and THA. At the 6-week time point, the peak serum d-dimer measurement resolved by 54.3% and 76.6% for TKA and THA, respectively. At 6 weeks after operation, 92% of THA patient and 100% of TKA patients had serum d-dimer measurements higher than the institutional threshold (0.40 µg/mL) for a "positive" quantitative test. No symptomatic DVTs were reported for the THA and TKA cohorts during the study period. CONCLUSION: The results suggest that serum d-dimer is an ineffective screening test for the diagnosis of symptomatic DVT in the acute postoperative period. The authors propose that extravascular fibrinolysis, a process essential for wound healing, has a crucial role in the prolonged elevation of serum d-dimer in the postoperative period.

Locking Versus Nonlocking Implants in Isolated Lower Extremity Fractures: Analysis of Cost and Complications.

The purpose of this study was to investigate operative costs and postoperative complication rates in relation to utilization of locking versus nonlocking implants in isolated, lower limb fractures. Seventy-seven patients underwent plate fixation of isolated bicondylar tibial plateau, bimalleolar ankle, and trimalleolar ankle fractures at a large tertiary care center. Fixation with locking versus nonlocking implants was compared to incidence of postsurgical complications. Costs of these implants were directly compared. No significant correlation was found between locking versus nonlocking implants and incidence of complications. However, the cost of fixation with locking implants was significantly greater than nonlocking for all fractures. Utilization of more costly locking implants was not associated with reduced postoperative complications compared with nonlocking implants. More attention must be dedicated toward maximizing cost efficiency, since uniform usage of nonlocking implants has the potential to reduce surgical costs without compromising patient outcomes in isolated lower extremity fractures.