No abstract

Myxofibrosarcoma (MFS) is a well‐recognized histotype of soft tissue sarcomas that generally presents with localized disease. Herein, we describe the case of a patient with metastatic MFS who experienced durable response to sixth‐line therapy with temozolomide. Upon further progression, his tumor was notable for a high tumor mutational burden, and he was subsequently treated with seventh‐line immunotherapy, atezolizumab, achieving a second durable response. This case highlights the role of immunotherapy after administration of alkylating agents. Review of the literature indicates that recurrent tumors treated with alkylating agents often experience hypermutation as a means of developing resistance and that checkpoint inhibitors are subsequently effective in these tumors. Key Points To the authors' knowledge, this is the first report of a patient with myxofibrosarcoma with high tumor mutational burden after administration of temozolomide monotherapy. Hypermutation may be a resistance mechanism for patients with soft tissue sarcoma who develop resistance to alkylating agents. Checkpoint inhibition may be effective therapy in patients with soft tissue sarcoma with high tumor mutational burden as a consequence of alternate systemic therapy resistance.

Study Design. Retrospective case series. Objective. We sought to identify risk factors associated with surgical site infection (SSI) after posterior long segment spinal fusion (PLSF). Summary of Background Data. Patients who undergo PLSF may be at elevated risk of SSI. Identifying factors associated with SSI in these operations can help risk stratify patients and tailor management. Methods. We analyzed PLSFs-seven or more levels-at our institution from 2000 to 2015. Data on patients' clinical characteristics, procedural factors, and antimicrobial management were collected. Multivariable analysis identified factors independently associated with outcomes of interest. Results. In 628 cases, SSI was associated with steroid use (P ¼ 0.024, odds ratio [OR] ¼ 2.54) and using cefazolin (P < 0.001, OR ¼ 4.37) or bacitracin (P ¼ 0.010, OR 3.49) irrigation, as opposed to gentamicin or other irrigation. Gram-positive infections were more likely with staged procedures (P ¼ 0.021, OR 4.91) and bacitracin irrigation (P < 0.001, OR ¼ 17.98), and less likely with vancomycin powder (P ¼ 0.050, OR 0.20). Gram-negative infections were more likely with a history of peripheral arterial disease (P ¼ 0.034, OR ¼ 3.21) or cefazolin irrigation (P < 0.001, OR 25.47). Readmission was more likely after staged procedures (P ¼ 0.003, OR ¼ 3.31), cervical spine surgery (P ¼ 0.023, OR ¼ 2.28), or cefazolin irrigation (P ¼ 0.039, OR ¼ 1.85). Reoperation was more common with more comor-bidities (P ¼ 0.022, OR 1.09), staged procedures (P < 0.001, OR ¼ 4.72), cervical surgeries (P ¼ 0.013, OR ¼ 2.36), more participants in the surgery (P ¼ 0.011, OR ¼ 1.06), using cefazolin (P < 0.001, OR ¼ 3.12) or bacitracin (P ¼ 0.009, OR ¼ 3.15) irrigation, and higher erythrocyte sedimentation rate at readmission (P ¼ 0.009, OR ¼ 1.04). Washouts were more likely among patients with more comorbidities (P ¼ 0.013, OR ¼ 1.16), or who used steroids (P ¼ 0.022, OR ¼ 2.92), and less likely after cervical surgery (P ¼ 0.028, OR ¼ 0.24). Instrumentation removal was more common with bacitracin irrigation (p ¼ 0.013, OR ¼ 31.76). Conclusion. Patient factors, whether a procedure is staged, and choice of antibiotic irrigation affect the risk of SSI and ensuing management required.

BACKGROUND:Most posterior spinal fusion (PSF) patients do not require admission to an intensive care unit (ICU), and those who do may represent an underinvestigated, high-risk subpopulation.OBJECTIVE:To identify the microbial profile of and risk factors for surgical site infection (SSI) in PSF patients admitted to the ICU postoperatively.METHODS:We examined 3965 consecutive PSF patients treated at our institution between 2000 and 2015 and collected demographic, clinical, and procedural data. Comorbid disease burden was quantified using the Charlson Comorbidity Index (CCI). We performed multivariable logistic regression to identify risk factors for SSI, readmission, and reoperation.RESULTS:Anemia, more levels fused, cervical surgery, and cerebrospinal fluid leak were positively associated with ICU admission, and minimally invasive surgery was negatively associated. The median time to infection was equivalent for ICU patients and non-ICU patients, and microbial culture results were similar between groups. Higher CCI and undergoing a staged procedure were associated with readmission, reoperation, and SSI. When stratified by CCI into quintiles, SSI rates show a strong linear correlation with CCI (P = .0171, R = 0.941), with a 3-fold higher odds of SSI in the highest risk group than the lowest (odds ratio = 3.15 [1.19, 8.07], P = .032).CONCLUSION:Procedural characteristics drive the decision to admit to the ICU postoperatively. Patients admitted to the ICU have higher rates of SSI but no difference in the timing of or microorganisms that lead to those infections. Comorbid disease burden drives SSI in this population, with a 3-fold greater odds of SSI for high-risk patients than low-risk patients.