Multisite Study of the Management of Musculoskeletal Infection After Trauma: The MMUSKIT Study.

Background: The optimal duration and choice of antibiotic for fracture-related infection (FRI) is not well defined. This study aimed to determine whether antibiotic duration (≤6 vs >6 weeks) is associated with infection- and surgery-free survival. The secondary aim was to ascertain risk factors associated with surgery- and infection-free survival. Methods: We performed a multicenter retrospective study of patients diagnosed with FRI between 2013 and 2022. The association between antibiotic duration and surgery- and infection-free survival was assessed by Cox proportional hazard models. Models were weighted by the inverse of the propensity score, calculated with a priori variables of hardware removal; infection due to Staphylococcus aureus, Staphylococcus lugdunensis, Pseudomonas or Candida species; and flap coverage. Multivariable Cox proportional hazard models were run with additional covariates including initial pathogen, need for flap, and hardware removal. Results: Of 96 patients, 54 (56.3%) received ≤6 weeks of antibiotics and 42 (43.7%) received >6 weeks. There was no association between longer antibiotic duration and surgery-free survival (hazard ratio [HR], 0.95; 95% CI, .65-1.38; P = .78) or infection-free survival (HR, 0.77; 95% CI, .30-1.96; P = .58). Negative culture was associated with increased hazard of reoperation or death (HR, 3.52; 95% CI, 1.99-6.20; P < .001) and reinfection or death (HR, 3.71; 95% CI, 1.24-11.09; P < .001). Need for flap coverage had an increased hazard of reoperation or death (HR, 3.24; 95% CI, 1.61-6.54; P = .001). Conclusions: The ideal duration of antibiotics to treat FRI is unclear. In this multicenter study, there was no association between antibiotic treatment duration and surgery- or infection-free survival.

Can gas and infection coexist in the intervertebral disc? A retrospective analysis of percutaneously biopsied suspected discitis-osteomyelitis cases.

OBJECTIVES: To retrospectively evaluate the correlation between intradiscal gas and infection in patients percutaneously biopsied for suspected discitis-osteomyelitis. MATERIALS AND METHODS: We retrospectively reviewed all CT-guided discitis-osteomyelitis biopsies performed between 2002 and 2022. Two independent trained musculoskeletal radiologists evaluated for presence of gas on CT and/or MRI within 1 week of the biopsy. Disagreements were resolved by a third musculoskeletal radiologist. CT was considered the gold standard for the detection of intradiscal gas. Pathology, microbiology, and imaging and clinical follow-up were used as the gold standard for presence of infection. Interrater agreement on CT and MRI, sensitivity, and positive predictive value were calculated, using the presence of gas as an indicator (test positive) for "no infection." RESULTS: There were 284 biopsies in 275 subjects (mean age 58 ± 1.0 (range 4-99) years; 101 (37%) females and 174 (63%) males). Of the biopsies, 12 (4%) were cervical, 80 (28%) were thoracic, 192 (68%) were lumbar, and 200 (70%) were considered true discitis-osteomyelitis based on pathology, imaging, and clinical follow-up. Interrater agreement was excellent for CT (kappa = 0.83) and poor for MRI (kappa = - 0.021). The presence of gas had a 94% specificity and 76% negative predictive value for the absence of infection. CONCLUSION: CT is the preferred method for detecting intradiscal gas. The presence of gas means that discitis-osteomyelitis is unlikely. If intradiscal gas is present in the setting of discitis-osteomyelitis, the gas bubbles tend to be smaller and fewer in number.

Periprosthetic Joint Infection: Current Clinical Challenges.

Over the last several decades, periprosthetic joint infection has been increasing in incidence and is occurring in more complex patients. While there have been advances in both surgical and medical treatment strategies, there remain important gaps in our understanding. Here, we share our current approaches to the diagnosis and management of periprosthetic joint infection, focusing on frequent clinical challenges and collaborative interdisciplinary care.

External validation of a predictive algorithm for in-hospital and 90-day mortality after spinal epidural abscess.

BACKGROUND CONTEXT: Mortality in patients with spinal epidural abscess (SEA) remains high. Accurate prediction of patient-specific prognosis in SEA can improve patient counseling as well as guide management decisions. There are no externally validated studies predicting short-term mortality in patients with SEA. PURPOSE: The purpose of this study was to externally validate the Skeletal Oncology Research Group (SORG) stochastic gradient boosting algorithm for prediction of in-hospital and 90-day postdischarge mortality in SEA. STUDY DESIGN/SETTING: Retrospective, case-control study at a tertiary care academic medical center from 2003 to 2021. PATIENT SAMPLE: Adult patients admitted for radiologically confirmed diagnosis of SEA who did not initiate treatment at an outside institution. OUTCOME MEASURES: In-hospital and 90-day postdischarge mortality. METHODS: We tested the SORG stochastic gradient boosting algorithm on an independent validation cohort. We assessed its performance with discrimination, calibration, decision curve analysis, and overall performance. RESULTS: A total of 212 patients met inclusion criteria, with a short-term mortality rate of 10.4%. The area under the receiver operating characteristic curve (AUROC) of the SORG algorithm when tested on the full validation cohort was 0.82, the calibration intercept was -0.08, the calibration slope was 0.96, and the Brier score was 0.09. CONCLUSIONS: With a contemporaneous and geographically distinct independent cohort, we report successful external validation of a machine learning algorithm for prediction of in-hospital and 90-day postdischarge mortality in SEA.

Peri-Prosthetic Joint Infection in Patients Prescribed Suppressive Antibiotic Therapy Undergoing Primary Total Joint Arthroplasty: A 1:4 Case Control Matched Study.

Background: Oral suppressive antibiotic therapy (SAT) has emerged as a potential means to increase rates of infection-free survival in many complex peri-prosthetic joint infection (PJI) cases after total joint arthroplasty (TJA). The purpose of the present study is to evaluate the risk of PJI of a new primary TJA in patients on oral SAT. Patients and Methods: A retrospective matched cohort study from five hospitals in a 20-year period within a large hospital network was performed. Inclusion criteria consisted of patients over age 18 undergoing primary TJA, with any order for oral long-term (>6 months duration) SAT, and minimum of one-year clinical follow-up. Patients were matched 1:4 on age, gender, body mass index (BMI), hip or knee surgery, diabetes mellitus, smoking status, and indication for primary TJA. Student t-test, Fisher exact, and χ2 tests were utilized for group comparisons. Our study was powered to detect a 10.5% increase in PJI incidence compared with a 1% baseline rate of PJI. Results: We identified 45 TJA in 33 patients receiving SAT, which were matched to 180 control cases. There was no difference in the rate of development of PJI at any time point within follow-up between the SAT cohort and control group (2.22% vs. 1.11%; p = 0.561). Conclusions: We found a 2.22% rate of PJI in a cohort of patients receiving SAT identified over a 20-year period. As the clinical scenario of primary TJA while on SAT is rare but likely to become more prevalent, future large-scale studies can be performed to better clarify rates and risk of PJI in this population.

Predictors of reoperation after surgery for spinal epidural abscess.

BACKGROUND CONTEXT: Spinal epidural abscess is a rare but severe condition with high rates of postoperative adverse events. PURPOSE: The objective of the study was to identify independent prognostic factors for reoperation using two datasets: an institutional and national database. STUDY DESIGN/SETTING: Retrospective Review. PATIENT SAMPLE: Database 1: Review of five medical centers from 1993 to 2016. Database 2: The National Surgical Quality Improvement Program (NSQIP) was queried between 2012 and 2016. OUTCOME MEASURES: Thirty-day and ninety-day reoperation rate. METHODS: Two independent datasets were reviewed to identify patients with spinal epidural abscesses undergoing spinal surgery. Multivariate analyses were used to determine independent prognostic factors for reoperation while including factors identified in bivariate analyses. RESULTS: Overall, 642 patients underwent surgery for a spinal epidural abscess in the institutional cohort, with a 90-day unplanned reoperation rate of 19.9%. In the NSQIP database, 951 patients were identified with a 30-day unplanned reoperation rate of 12.3%. On multivariate analysis in the NSQIP database, cervical spine abscess was the only factor that reached significance for 30-day reoperation (OR=1.71, 95% CI=1.11-2.63, p=.02, Area under the curve (AUC)=0.61). On multivariate analysis in the institutional cohort, independent prognostic factors for 30-day reoperation were: preoperative urinary incontinence, ventral location of abscess relative to thecal sac, cervical abscess, preoperative wound infection, and leukocytosis (AUC=0.65). Ninety-day reoperation rate also found hypoalbuminemia as a significant predictor (AUC=0.66). CONCLUSION: Six novel independent prognostic factors were identified for 90-day reoperation after surgery for a spinal epidural abscess. The multivariable analysis fairly predicts reoperation, indicating that there may be additional factors that need to be uncovered in future studies. The risk factors delineated in this study through the use of two large cohorts of spinal epidural abscess patients can be used to improve preoperative risk stratification and patient management.

Outcomes of Concurrent Endocarditis and Periprosthetic Joint Infection: A Retrospective Case Series of 16 Patients.

Introduction Concurrent diagnosis of periprosthetic joint infection (PJI) of total hip arthroplasty (THA) or total knee arthroplasty (TKA) with infectious endocarditis is a devastating clinical scenario infrequently documented in the literature. To date, no studies have fully described the orthopedic and infectious outcomes of patients with these concurrent diagnoses. The purpose of this study was to conduct a case series of patients with these diagnoses and document the orthopedic and infectious outcomes so that surgeons may effectively counsel patients regarding the gravity of the condition and the expected course of treatment. Methods This study is a retrospective case series using patient data from five hospitals within an academic healthcare system in the northeastern United States. Cases of concurrent endocarditis and THA or TKA PJI with a minimum of one-year follow-up were identified from January 2000 to January 2021. Basic statistics such as means, standard deviations, and percentages were used to identify trends within our series. Kaplan-Meier survivorship curves with log-rank tests were performed to determine if there were any differences in two-year mortality and joint survival (defined as needing explant) between patients who had cardiac surgery prior to surgical management for their PJI and those who had surgical management for PJI prior to cardiac surgery. Results A total of 18 joints in 16 patients with endocarditis and concurrent TKA or THA PJI were identified. All PJIs were managed surgically, with 14/18 (77.77%) of joint infections initially being managed by debridement, antibiotics, and implant retention (DAIR) and 4/18 (22.22%) of joint infections initially being managed by explant. Within the first six months of PJI diagnosis, 25% (4/16) of patients died of complications related to their infection, and one additional patient died of bacteremia just over a year after the initial PJI diagnosis. Of the 18 PJIs, 72.23% (13/18) had treatment failure, defined as any outcome equal to or worse than requiring chronic suppressive antibiotics for the infection. Due to low statistical power, we were not able to identify any differences in two-year mortality from PJI diagnosis (p=0.311) or joint survival (in terms of requiring explant) (p=0.420) depending on whether cardiac surgery or DAIR was performed first. Conclusions Concurrent infectious endocarditis and prosthetic joint infection is associated with high morbidity and mortality. Patients with these concurrent infections should be counseled that not only the associated mortality rate is high, but also the surgical treatment of their PJI has a high rate of treatment failure, including an explant following an initial DAIR, an explant with retained spacer, or a requirement of lifelong antibiotic suppression.

Creation of a Multidisciplinary Drug Use Endocarditis Treatment (DUET) Team: Initial Patient Characteristics, Outcomes, and Future Directions.

BACKGROUND: Consensus guidelines recommend multidisciplinary models to manage infective endocarditis, yet often do not address the unique challenges of treating people with drug use-associated infective endocarditis (DUA-IE). Our center is among the first to convene a Drug Use Endocarditis Treatment (DUET) team composed of specialists from Infectious Disease, Cardiothoracic Surgery, Cardiology, and Addiction Medicine. METHODS: The objective of this study was to describe the demographics, infectious characteristics, and clinical outcomes of the first cohort of patients cared for by the DUET team. This was a retrospective chart review of patients referred to the DUET team between August 2018 and May 2020 with DUA-IE. RESULTS: Fifty-seven patients were presented to the DUET team between August 2018 and May 2020. The cohort was young, with a median age of 35, and injected primarily opioids (82.5% heroin/fentanyl), cocaine (52.6%), and methamphetamine (15.8%). Overall, 14 individuals (24.6%) received cardiac surgery, and the remainder (75.4%) were managed with antimicrobial therapy alone. Nearly 65% of individuals were discharged on medication for opioid use disorder, though less than half (36.8%) were discharged with naloxone and only 1 patient was initiated on HIV pre-exposure prophylaxis. Overall, the cohort had a high rate of readmission (42.1%) within 90 days of discharge. CONCLUSIONS: Multidisciplinary care models such as the DUET team can help integrate nuanced decision-making from numerous subspecialties. They can also increase the uptake of addiction medicine and harm reduction tools, but further efforts are needed to integrate harm reduction strategies and improve follow-up in future iterations of the DUET team model.

Antiplatelet therapy for Staphylococcus aureus bacteremia: Will it stick?

Staphylococcus aureus bacteremia (SAB) remains a clinically challenging infection despite extensive investigation. Repurposing medications approved for other indications is appealing as clinical safety profiles have already been established. Ticagrelor, a reversible adenosine diphosphate receptor antagonist that prevents platelet aggregation, is indicated for patients suffering from acute coronary syndrome (ACS). However, some clinical data suggest that patients treated with ticagrelor are less likely to have poor outcomes due to S. aureus infection. There are several potential mechanisms by which ticagrelor may affect S. aureus virulence. These include direct antibacterial activity, up-regulation of the innate immune system through boosting platelet-mediated S. aureus killing, and prevention of S. aureus adhesion to host tissues. In this Pearl, we review the clinical data surrounding ticagrelor and infection as well as explore the evidence surrounding these proposed mechanisms of action. While more evidence is needed before antiplatelet medications formally become part of the arsenal against S. aureus infection, these potential mechanisms represent exciting pathways to target in the host/pathogen interface.

Best Practices: CT-Guided Percutaneous Sampling of Vertebral Discitis-Osteomyelitis and Technical Factors Maximizing Biopsy Yield.

Vertebral discitis-osteomyelitis is an infection of the intervertebral disk and vertebral bodies that may extend to adjacent paraspinal and epidural soft tissues. Its incidence is increasing, likely because of improved treatments and increased life expectancy for patients with predisposing chronic disease and increased rates of IV drug use and intravascular intervention. Because blood cultures are frequently negative in patients with vertebral discitis-osteomyelitis, biopsy is often indicated to identify a causative microorganism for targeted antimicrobial therapy. The reported yield of CT-guided percutaneous sampling is 31-91%, which is lower than the reported yield of open biopsy of 76-91%. However, the less invasive approach may be favored given its relative safety and low cost. If paravertebral fluid collections are present, CT-guided aspiration should be performed. If aspiration is unsuccessful or no paravertebral fluid collections are present, CT-guided percutaneous biopsy should be performed, considering technical factors (e.g., anatomic approach, needle selection, and needle angulation) that may improve microbiologic yield. Although antimicrobial therapy should be withheld for 1-2 weeks before biopsy if clinically feasible, biopsy may still be performed without stopping antimicrobial therapy if needed. Because of the importance of targeted antimicrobial therapy, repeat biopsy should be considered after 72 hours if initial biopsy does not identify a pathogen.

CT-guided discitis-osteomyelitis biopsies: needle gauge and microbiology results.

PURPOSE: To compare the microbiology results and needle gauge for CT-guided biopsies of suspected discitis-osteomyelitis. METHODS: All CT-guided biopsies performed for suspected discitis-osteomyelitis at our institution between 2002 and 2019 were reviewed. Biopsy location, needle type and gauge, microbiology, pathology, and clinical and imaging follow-up were obtained through chart review. Yield, sensitivity, specificity, and accuracy were calculated. A pairwise analysis of different needle gauges was also performed with calculations of odds ratios. Naïve Bayes predictive modeling was performed. RESULTS: 241 (age: 59 ± 18 years; 88 [35%] F, 162 [65%] M) biopsies were performed. There were 3 (1%) 11 gauge (G), and 13 (5%) 12-G biopsies; 23 (10%) 13-G biopsies; 75 (31%) 14-G biopsies; and 90 (37%) 16-G, 33 (14%) 18-G, and 4 (2%) 20 G biopsies. True disease status (presence of infection) was determined via either pathology findings (205, 86%) or clinical and imaging follow-up (36, 14%). The most common true positive pathogen was Staphylococcus aureus (31, 33%). Overall biopsy yield, sensitivity, specificity, and accuracy were 39%, 56%, 89%, and 66%, respectively. Pooled biopsy yield, sensitivity, specificity, and accuracy was 56%, 69%, 71%, and 69% for 11-13-G needles and 36%, 53%, 91%, and 65% for 14-20-G needles, respectively, with an odds ratio between the two groups of 2.29 (P = 0.021). Pooled biopsy yield, sensitivity, specificity, and accuracy was 48%, 63%, 85%, and 68% for 11-14-G needles and 32%, 49%, 91%, and 64% for 16-20-G needles, respectively, with an odds ratio between the two groups of 2.02 (P = 0.0086). CONCLUSION: The use of a larger inner bore diameter/lower gauge biopsy needle may increase the likelihood of culturing the causative microorganism for CT-guided biopsies of discitis-osteomyelitis.

MRI and clinical features of acute fungal discitis/osteomyelitis.

OBJECTIVES: To compare imaging and clinical features of fungal and Staphylococcus aureus discitis-osteomyelitis (DO) for patients presenting for CT-guided biopsies. METHODS: Our study was IRB-approved and HIPAA-compliant. A group of 11 fungal DO (FG) with MRI within 7 days of the biopsy and a control group (CG) of 19 Staphylococcus aureus DO were evaluated. Imaging findings (focal vs diffuse paravertebral soft tissue abnormality, partial vs complete involvement of the disc/endplate), biopsy location, pathology, duration of back pain, immune status, history of intravenous drug, history of prior infection, current antibiotic treatment, and history of invasive intervention. Differences were assessed using the Fisher exact test and Kruskal-Wallis test. Naïve Bayes predictive modeling was performed. RESULTS: The most common fungal organisms were Candida species (9/11, 82%). The FG was more likely to have focal soft tissue abnormality (p = 0.040) and partial disc/endplate involvement (p = 0.053). The clinical predictors for fungal DO, in order of importance, back pain for 10 or more weeks, current antibiotic use for 1 week or more, and current intravenous drug use. History of invasive instrumentation within 1 year was more predictive of Staphylococcus aureus DO. CONCLUSION: MRI features (focal partial soft tissue abnormality and partial involvement of the disc/endplate) in combination with clinical features may help to predict fungal species as a causative organism for DO. KEY POINTS: • MRI features of discitis-osteomyelitis (focal partial soft tissue abnormality and partial involvement of the disc/endplate) in combination with clinical features may help to predict fungal species as a causative organism for DO.

CT-guided discitis-osteomyelitis biopsies with negative microbiology: how many days should we wait before repeating the biopsy?

PURPOSE: To determine the number of days to positive CT-guided biopsy sample culture in patients with discitis-osteomyelitis. METHODS: Our study was IRB approved and HIPAA compliant. All CT-guided biopsies performed for acute discitis-osteomyelitis with positive microbiology between 2002 and 2018 were reviewed. Microbiological organism and days to positive biopsy were documented. Mean, median, skew, and standard deviation were calculated. The proportion of positive cultures that become positive after each day has elapsed was also calculated. RESULTS: There were 96 true positive cultures, with 64 (67%) male and 32 (33%) female, ages 57 ± 18 (range 19-87) years. Overall, including all culture results, the mean number of days to positive culture was 2.9 ± 3.5 days. The median number of days was 2, with a positive skew of 2.9. At days 1, 2, 3, 4, and 5, 48%, 68%, 78%, 85%, and 89%, respectively, of biopsy samples had a positive microbiology culture. CONCLUSION: Approximately three-quarters of discitis-osteomyelitis pathogens will be identified by biopsy sample culture by 3 days after CT-guided biopsy. This finding should be considered if planning for a repeat biopsy in the setting of a negative microbiology culture.

Development of machine learning algorithms for prediction of mortality in spinal epidural abscess.

BACKGROUND CONTEXT: In-hospital and short-term mortality in patients with spinal epidural abscess (SEA) remains unacceptably high despite diagnostic and therapeutic advancements. Forecasting this potentially avoidable consequence at the time of admission could improve patient management and counseling. Few studies exist to meet this need, and none have explored methodologies such as machine learning. PURPOSE: The purpose of this study was to develop machine learning algorithms for prediction of in-hospital and 90-day postdischarge mortality in SEA. STUDY DESIGN/SETTING: Retrospective, case-control study at two academic medical centers and three community hospitals from 1993 to 2016. PATIENTS SAMPLE: Adult patients with an inpatient admission for radiologically confirmed diagnosis of SEA. OUTCOME MEASURES: In-hospital and 90-day postdischarge mortality. METHODS: Five machine learning algorithms (elastic-net penalized logistic regression, random forest, stochastic gradient boosting, neural network, and support vector machine) were developed and assessed by discrimination, calibration, overall performance, and decision curve analysis. RESULTS: Overall, 1,053 SEA patients were identified in the study, with 134 (12.7%) experiencing in-hospital or 90-day postdischarge mortality. The stochastic gradient boosting model achieved the best performance across discrimination, c-statistic=0.89, calibration, and decision curve analysis. The variables used for prediction of 90-day mortality, ranked by importance, were age, albumin, platelet count, neutrophil to lymphocyte ratio, hemodialysis, active malignancy, and diabetes. The final algorithm was incorporated into a web application available here: https://sorg-apps.shinyapps.io/seamortality/. CONCLUSIONS: Machine learning algorithms show promise on internal validation for prediction of 90-day mortality in SEA. Future studies are needed to externally validate these algorithms in independent populations.

Development of a machine learning algorithm for prediction of failure of nonoperative management in spinal epidural abscess.

BACKGROUND CONTEXT: Data regarding risk of failure of nonoperative management in spinal epidural abscess (SEA) are limited. Given the potential for deterioration with treatment failure, a tool that predicts the probability of failure would be of great clinical utility. PURPOSE: We primarily aim to build a machine learning model using independent predictors of nonoperative management failure. Secondarily, we aim to develop an open-access web-based application that provides a patient-specific probability of treatment failure. STUDY DESIGN/SETTING: Retrospective, case-control study. PATIENT SAMPLE: Patients 18 years or older diagnosed with SEA at 2 academic medical centers and 3 community hospitals. OUTCOME MEASURES: Failure of nonoperative management. METHODS: This is a retrospective cohort study of 367 patients with SEA initially managed nonoperatively between 1993 and 2016. The primary outcome was failure of nonoperative management defined as neurologic deterioration, worsened back and/or radicular pain, or persistent symptoms despite initiation of antibiotic therapy. Five machine learning algorithms were developed and assessed by discrimination, calibration, and overall performance. RESULTS: Ninety-nine (27%) patients failed nonoperative management. Factors determined for prediction of nonoperative management were: motor deficit, diabetes, ventral component of abscess relative to thecal sac, history of compression or pathologic vertebral fracture, sensory deficit, active malignancy, and involvement of 3 or more vertebral levels. The elastic-net penalized logistic regression model was chosen as the final model given its superior discrimination, calibration, and overall model performance. This model was incorporated into an open access web application. CONCLUSION: By building a discriminative and well-calibrated model in a user-friendly and open-access digital interface, we hope to provide a prognostic tool that can be used to inform clinical decision-making in real-time.

Neutrophil to lymphocyte ratio and mortality in spinal epidural abscess.

BACKGROUND CONTEXT: Neutrophil to lymphocyte ratio and platelet to lymphocyte ratio have been previously identified as markers for overall survival in oncology but remain heretofore unexplored in spinal epidural abscess (SEA). PURPOSE: The purpose of this study was to determine the impact of these routinely collected assessments on 90-day mortality in SEA. STUDY DESIGN/SETTING: Retrospective, case-control study. PATIENT SAMPLE: Patients 18 years or older diagnosed with SEA at 2 academic medical centers and 3 community hospitals. OUTCOME MEASURES: Ninety-day postdischarge and in-hospital mortality. METHODS: Complete blood count with differential obtained on the day immediately preceding or on the day of admission was used to calculate platelet to lymphocyte and neutrophil to lymphocyte ratios. Multivariate analyses were used to determine if these ratios were independent risk factors for 90-day mortality. RESULTS: For 1,053 SEA patients included in the study, the rate of 90-day mortality was 134 (12.7%). The rate of 90-day mortality with neutrophil to lymphocyte ratio (≥8) was (20.5%) compared to (8.1%) with neutrophil to lymphocyte ratio <8. Neutrophil to lymphocyte ratio was positively associated with bacteremia, elevated erythrocyte sedimentation rate, and concurrent systemic infections (endocarditis, meningitis) and negatively associated with duration of symptoms prior to presentation. On multivariate analysis, elevated neutrophil to lymphocyte remained an independent risk factor for 90-day mortality (odds ratio=2.62, 95% confidence interval=1.66-4.17, p<.001). Platelet to lymphocyte ratio was not associated with 90-day mortality. CONCLUSIONS: Absolute neutrophil to lymphocyte ratio is a routinely collected but overlooked biomarker in patients with spinal epidural abscess that is a novel independent risk factor for 90-day mortality.

Albumin and Spinal Epidural Abscess: Derivation and Validation in Two Independent Data Sets.

BACKGROUND: None of the existing prognostic scoring systems for spinal epidural abscess (SEA) include albumin despite albumin's established role in inflammation, nutrition, lipid peroxidation, and regulation of apoptosis. The purpose of the present study was to determine the prognostic value of albumin in SEA. METHODS: We performed a retrospective, case-control study of 2 independent data sets: patients with SEA in an institutional population and patients in the National Surgical Quality Improvement Program (NSQIP). Bivariate analyses and multivariate analyses were used to determine whether albumin is an independent prognostic factor for survival in both data sets. RESULTS: For the 1053 patients with SEA in the institutional cohort, the 90-day postdischarge mortality was 134 (12.7%). Overall, 633 (60.1%) underwent surgery in the initial admission, with a 30-day postoperative mortality rate of 5.5% (n = 35). For the 1154 patients with SEA in the NSQIP database, the 30-day postoperative mortality rate was 3.6% (n = 42). The rate of 90-day postdischarge mortality in the institutional cohort for patients with albumin <2.3 g/dL was 25.1%. In contrast, the rate for patients with albumin >3.3 g/dL was 4.5%. On multivariate analysis of the NSQIP database, hypoalbuminemia was an independent prognostic factor for 30-day postoperative mortality. On multivariate analysis of the institutional cohort, hypoalbuminemia remained a prognostic factor for 90-day postdischarge mortality. CONCLUSION: Albumin was validated as an independent prognostic factor in patients with SEA. The lack of this marker in existing scoring systems underscores the need for updated models to optimize risk stratification and shared decision-making before surgery.

Fungal spinal epidural abscess: a case series of nine patients.

BACKGROUND CONTEXT: Fungal spinal epidural abscess (FSEA) is a rare entity with high morbidity and mortality. Reports describing the clinical features, diagnosis, treatment, and outcomes of FSEA are scarce in the literature. PURPOSE: This study aimed to describe the clinical features, diagnosis, treatment, and outcomes of FSEA. STUDY DESIGN: This study is designed as a retrospective clinical case series. PATIENT SAMPLE: A continuous series of patients with the diagnosis of FSEA who presented at our institution from 1993 to 2016. METHODS: We reviewed the electronic medical records of patients with SEA who were treated within our hospital system from 1993 to 2016. We only included SEA cases that were due to fungi. We also reviewed FSEA cases in the English language literature from 1952 to 2017 to analyze the features of FSEA. RESULTS: From a database of 1,053 SEA patients, we identified 9 patients with FSEA. Aspergillus fumigatus was isolated from 2 (22%) patients, and Candida species were isolated from 7 (78%). Focal spine pain, neurologic deficit, and fever were demonstrated in 89%, 50%, and 44% of FSEA cases, respectively. Five of nine cases involved the thoracic spine, and eight were located anterior to the thecal sac. Three cases had fungemia, six had long symptom duration (>2 weeks) prior to presentation, seven had concurrent immunosuppression, and eight had vertebral osteomyelitis. Additionally, one case had residual motor deficit at last follow-up, one had S1 sensory radicular symptoms, two suffered recurrent FSEA, two died within hospitalization, and two died within 90 days after discharge. CONCLUSIONS: In summary, the classic diagnostic triad (focal spine pain, neurologic deficit, and fever) is not of great clinical utility for FSEA. Biopsy, intraoperative tissue culture, and blood culture can be used to diagnose FSEA. The most common pathogens of FSEA are Aspergillus and Candida species. Therefore, empiric treatment for FSEA should cover these species while definitive identification is pending. FSEA is found in patients with poor baseline health status, which is the essential reason for its high mortality.

Mycobacterial Musculoskeletal Infections.

Although less common as causes of musculoskeletal infection than pyogenic bacteria, both Mycobacterium tuberculosis and nontuberculous mycobacteria can infect bones and joints. Although tuberculous arthritis and osteomyelitis have been recognized for millennia, infections caused by nontuberculous mycobacteria are being identified more often, likely because of a more susceptible host population and improvements in diagnostic capabilities. Despite advances in modern medicine, mycobacterial infections of the musculoskeletal system remain particularly challenging to diagnose and manage. This article discusses clinical manifestations of musculoskeletal infections caused by Mycobacterium tuberculosis and nontuberculous mycobacteria. Pathogenesis, unique risk factors, and diagnostic and therapeutic approaches are reviewed.

Mycobacterium abscessus: A Rare Cause of Periprosthetic Knee Joint Infection.

A 61-year-old woman with a periprosthetic knee joint infection caused by Mycobacterium abscessus was successfully treated with surgical débridement, multidrug antimicrobial therapy, and staged reimplantation. To the authors' knowledge, this represents the first report of successfully treating this organism after knee arthroplasty. M. abscessus knee infections are rare, and there are no specific guidelines to inform treatment or successful treatment regimens for periprosthetic knee infections. Medical management alone was not successful in this case and hence cannot be recommended. Using a collaborative multidisciplinary approach, including surgical débridement, staged reimplantation, and multidrug antimicrobials, successful eradication of the periprosthetic joint infection caused by M. abscessus was achieved.