Periprosthetic Knee Infection - Part 1: Risk Factors, Classification and Diagnosis / Infecção periprotética do joelho - Parte 1: Fatores de risco, classificação e diagnóstico

Abstract Infection is one of the most feared complications in the postoperative period of knee arthroplasties. With the progressive aging of the population and the increased incidence of degenerative joint diseases, there is an exponential increase in the number of arthroplasties performed and, consequently, in the number of postoperative infections. The diagnosis of these should follow a hierarchical protocol, with welldefined criteria, which lead to diagnostic conclusion, thus guiding the most appropriate treatment. The aim of the present update article is to present the main risk factors, classifications and, mainly, to guide diagnostic investigation in an organized manner.

Resumo A infecção é uma das complicações mais temidas no pós-operatório de artroplastias do joelho. Com o envelhecimento populacional progressivo e o aumento da incidência de doenças degenerativas articulares, observa-se um aumento exponencial do número de artroplastias realizadas e, consequentemente, do número de infecções pós-operatórias. O diagnóstico destas devem seguir um protocolo hierarquizado, com critérios bem definidos, que conduzam à conclusão diagnóstica, orientando, assim, o tratamento mais adequado. O objetivo do presente artigo de atualização é apresentar os principais fatores de risco, as classificações e, principalmente, guiar de forma organizada a investigação diagnóstica.

Prognostic Value of Surgical Site Infection in Patients After Radical Colorectal Cancer Resection.

BACKGROUND This study aimed to evaluate the clinicopathological factors associated with surgical site infection (SSI) and the prognostic impact on patients after colorectal cancer (CRC) resection surgery. MATERIAL AND METHODS This retrospective study evaluated the relationships between SSI and various clinicopathological factors and prognostic outcomes in 326 consecutive patients with CRC who underwent radical resection surgery at Wuhan Union Hospital during April 2015-May 2017. RESULTS Among the 326 patients who underwent radical CRC resection surgery, 65 had SSIs, and the incidence rates of incisional and organ/space SSI were 16.0% and 12.9%, respectively. Open surgery, chronic obstructive pulmonary disease (COPD), and a previous abdominal surgical history were identified as risk factors for incisional SSI. During a median follow-up of 40 months (range: 5-62 months), neither simple incisional nor simple organ/space SSI alone significantly affected disease-free survival (DFS) or overall survival (OS), whereas combined incisional and organ/space SSI had a significant negative impact on both the 3-year DFS and OS (P<0.001). A multivariate analysis identified that age ≥60 years, lymph node involvement, tumor depth (T3-T4), and incisional and organ/space SSI were independent predictors of 3-year DFS and OS. In addition, adjuvant chemotherapy and a carbohydrate antigen-125 concentration ≥37 ng/ml were also independent predictors of OS. CONCLUSIONS We have identified several clinicopathological factors associated with SSI, and identified incisional and organ/space SSI is an independent prognostic factor after CRC resection. Assessing the SSI classification may help to predict the prognosis of these patients and determine further treatment options.

Prevention, Classification and Management Review of Deep Sternal Wound Infection.

Sternal wound complications are significant problems in cardiac surgery and cause challenges to surgeons as they are associated with high mortality, morbidity, and a tremendous load on the hospital budget. Risk factors and preventive measures against sternal wound infection need to be in focus. Classification of different types of sternotomy complications post cardiac surgery is important for specific categorization and management. Reviewing the literature, a variety of classifications was introduced to help understand the pathophysiology of these wounds and how best to manage them. Initial classifications were based on the postoperative period of the infectious process and risk factors. Recently, the anatomical description of sternal wound, including the depth and location, was shown to be more practical. There is a lack of evidence-based surgical consensus for the appropriate management strategy, including type of closure, choice of sternal coverage post sternectomy, whether primary, delayed and when to use reconstructive flaps.

Phenotypic heterogeneity by site of infection in surgical sepsis: a prospective longitudinal study.

BACKGROUND: The role of site of infection in sepsis has been poorly characterized. Additionally, sepsis epidemiology has evolved. Early mortality has decreased, but many survivors now progress into chronic critical illness (CCI). This study sought to determine if there were significant differences in the host response and current epidemiology of surgical sepsis categorized by site of infection. STUDY DESIGN: This is a longitudinal study of surgical sepsis patients characterized by baseline predisposition, insult characteristics, serial biomarkers, hospital outcomes, and long-term outcomes. Patients were categorized into five anatomic sites of infection. RESULTS: The 316 study patients were predominantly Caucasian; half were male, with a mean age of 62 years, high comorbidity burden, and low 30-day mortality (10%). The primary sites were abdominal (44%), pulmonary (19%), skin/soft tissue (S/ST, 17%), genitourinary (GU, 12%), and vascular (7%). Most abdominal infections were present on admission and required source control. Comparatively, they had more prolonged proinflammation, immunosuppression, and persistent organ dysfunction. Their long-term outcome was poor with 37% CCI (defined as > 14 in ICU with organ dysfunction), 49% poor discharge dispositions, and 30% 1-year mortality. Most pulmonary infections were hospital-acquired pneumonia. They had similar protracted proinflammation and organ dysfunction, but immunosuppression normalized. Long-term outcomes are similarly poor (54% CCI, 47% poor disposition, 32% 1-year mortality). S/ST and GU infections occurred in younger patients with fewer comorbidities, less perturbed immune responses, and faster resolution of organ dysfunction. Comparatively, S/ST had better long-term outcomes (23% CCI, 39% poor disposition, 13% 1-year mortality) and GU had the best (10% CCI, 20% poor disposition, 10% 1-year mortality). Vascular sepsis patients were older males, with more comorbidities. Proinflammation was blunted with baseline immunosuppression and organ dysfunction that persisted. They had the worst long-term outcomes (38% CCI, 67% poor disposition, 57% 1-year mortality). CONCLUSION: There are notable differences in baseline predisposition, host responses, and clinical outcomes by site of infection in surgical sepsis. While previous studies have focused on differences in hospital mortality, this study provides unique insights into the host response and long-term outcomes associated with different sites of infection.

Sternal Wound Complications: Objective Reclassification and Surgical Reconsideration.

Background: Sternal wound complications pose a tremendous challenge post-cardiac surgery. There's no consensus or clear guidelines to deal with them. We propose that simple and more objective classification helps to organize the range of sternal wound complications and suggest a relevant treatment strategy. Methods: One-hundred-sixteen cases of sternal wound complications retrospectively were reviewed out of 2,391 adult patients, who underwent full sternotomy during cardiac surgery from 2006 to 2018. Eighty-six cases conservatively were managed and the remaining 30 cases required surgical intervention. More objective classification was proposed and less invasive fasciocutaneous flap was considered for nearly all reconstructive procedures. Results: The incidence of sternal wound complications was 4.8%. Conservative management was adopted for 86 cases, mean duration was 11.19 ± 9.8 days. Surgical management was performed in 30 patients (25.86%); 28 (93.3%) of whom recovered with good outcomes with less invasive fasciocutaneous flap done for 13 cases. Two cases had recurrence; one conservatively was managed and other was reoperated and healed well. The most common organisms in recurrent infections were N. coagulase (29.8%), Klebsiella (12.5%), pseudomonas (10.5%), and MRSA (10.5%). We had 4 mortalities. None of the mortalities were related to sternal wound complications; one was related to the cardiac surgery. Conclusions: Sternal wound complications are grave events. Objective classification and proper management selection will gain better outcomes.

Use of health databases to deal with underreporting of surgical site infections due to suboptimal post-discharge follow-up.

This study describes a combined surveillance of surgical site infection implemented in an Italian region, which relies on integration of the specific surveillance (SIChER) with other sources and the targeted review of a small proportion of cases. Additional information on post-surgical follow-up was obtained from hospital discharge, microbiology laboratory and emergency department databases. Based on these data, 76 patients were reclassified as possible cases and revised by the health trust representatives. Eventually 45 new cases were confirmed, leading to an increase in the infection ratio from 1.13% to 1.45%. The proposed method appears to be accurate and sustainable over time.

Proposed Classification of Incision Complications: Analysis of a Prospective Study on Elective Open Lower-Limb Revascularization.

Background: Incision complications (IC) have a significant impact on procedure-related morbidity after lower-limb revascularization. One of the most studied IC is surgical site infection (SSI). Reporting these complications in a uniform way is crucial to evaluate treatment approaches. The aim of this study was to propose a comprehensive classification of IC and apply it to compare SSI with other IC in a trial on elective open lower-limb revascularization procedures. Methods: Two hundred twenty-three eligible patients undergoing elective unilateral inguinal and infra-inguinal arterial vascular surgery were extracted from a randomized controlled trial on incisional negative-pressure wound therapy (NPWT) on inguinal vascular surgical incisions. The IC were classified by grades of severity (grade 0-6) that focused on IC-related consequences such as out-patient treatment (grade 1), prolonged in-patient treatment (grade 2), re-admission (grade 3), and re-operation (grade ≥4). An SSI was defined by the ASEPSIS score criteria. Results: An SSI was diagnosed in 63 patients (28.3%). Thirty-five of 160 patients (21.8%) not suffering from SSI underwent IC treatment. Treatment for IC was recorded for 25/144 patients (17.4%) with satisfactory site healing as judged by the ASEPSIS score. The median incision-related in-hospital stay in those with SSI (n = 79) and disturbed healing (n = 16) according to the ASEPSIS score was 13 days in both groups (p = 0.53). Five patients had peri-vascular SSI (IC grade 4 n = 4; grade 5 n = 1). The proposed classification of IC and the ASEPSIS score correlated highly (r = 0.77; p < 0.001). Inter-rater reliability for IC grading was substantial for three investigators with different levels of experience (k = 0.81, 0.71, and 0.70). Conclusions: The proposed incision classification suggests a comparable clinical significance of vascular IC in terms of IC-related in-patient stay, whether there was a surgical site infection or not. This classification system requires external validation.

Management of Surgical Site Infections.

The American Academy of Orthopaedic Surgeons has developed Appropriate Use Criteria for the Management of Surgical Site Infections (SSIs) (website: http://www.orthoguidelines.org/go/auc/default.cfm?auc_id=225018&actionxm=Terms). Evidence-based information, in conjunction with the clinical expertise of physicians, was used to develop the criteria to improve patient care and obtain best outcomes while considering the subtleties and distinctions necessary in making clinical decisions. The Appropriate Use Criteria for the Management of SSIs were derived by identifying clinical indications typical of patients commonly presenting with a SSI in clinical practice. These indications were most often parameters observable by the clinician, including symptoms and diagnostic tests. The 264 patient scenarios and nine treatments were developed by the writing panel, which consisted of a group of clinicians who are specialists in this Appropriate Use Criteria topic. Next, a separate, multidisciplinary, voting panel (made up of specialists and nonspecialists) rated the appropriateness of treatment of each patient scenario using a nine-point scale to designate a treatment as appropriate (median rating, seven to nine), may be appropriate (median rating, four to six), or rarely appropriate (median rating, one to three).

Primary Skin Closure after Repair of Hollow Viscus Injuries.

Decisions regarding whether to close the skin in trauma patients with hollow viscus injuries (HVIs) are based on surgeon discretion and the perceived risk for an SSI. We hypothesized that leaving the skin open would result in fewer wound complications in patients with HVIs. We performed a retrospective analysis of all adult patients who underwent operative repair of an HVI. The main outcome measure was superficial or deep SSIs. Of 141 patients, 38 (27%) had HVIs. Twenty-six patients developed SSIs, of which 13 (50%) were superficial or deep SSIs. On adjusted analysis, only female gender (P = 0.03) and base deficit were associated (P = 0.001) with wound infections Open wound management was not associated with a decreased incidence of SSIs (P = 0.19) in patients with HVIs. Further research is required to determine optimal strategies for reducing wound complications in patients sustaining HVIs.

Evidence-based wound classification for vulvar surgery: Implications for risk adjustment.

OBJECTIVES: The correct wound classification for vulvar procedures (VP) is ambiguous according to current definitions, and infection rates are poorly described. We aimed to analyze rates of surgical site infection (SSI) in women who underwent VP to correctly categorize wound classification. METHODS: Patients who underwent VP for dysplasia or carcinoma were collected from the National Surgical Quality Improvement Program database (NSQIP). SSI rates of vulvar cases were compared to patients who underwent abdominal hysterectomy via laparotomy, stratified by the National Academy of Sciences wound classification. Descriptive analyses and trend tests of categorical variables were performed. RESULTS: Between 2008 and 2016, 2116 and 31,506 patients underwent a VP or TAH, respectively. Among VP, 1345 (63.6%), 364 (17.2%), and 407 (19.2%) women underwent simple vulvectomy, radical vulvectomy, or radical vulvectomy with lymphadenectomy, respectively. The overall rate of SSI for VP was higher than that observed for TAH (5.6% vs. 3.8%; p < 0.0001). While patients undergoing TAH displayed a corresponding increase in the rate of SSI with wound type (type I: 3.4%; type II: 3.8%, type III: 6.8%; type IV 10.6%; p < 0.001), no such correlation was observed for simple VP (type I: 3.3%, type II: 3.0%; type III: 3.2%; type IV: 0%; p = 0.40). On the other hand, a non-significant correlation was observed for radical VP (type I: 4.0%, type II: 10.1%; type III: 14.3%; type IV: 20.0%; p = 0.08). The overall rate of SSI in patients undergoing any radical VP was similar to patients undergoing hysterectomy with a type IV wound (10.1% vs 10.6%, p = 0.87). CONCLUSION: Patients undergoing VP are at high risk of infection. Simple vulvectomy should be classified as a type II and radical vulvectomy as a type III wound. These recommendations are important for proper risk adjustment.

Classification of breast tissue expander infections: Back to the basics.

BACKGROUND: Infections following tissue expander (TE) placement are frequent complications in breast reconstruction. While breast surgery is a clean case, implant-based breast reconstruction has rates of infection up to 31%, decidedly higher than the typical 1% to 2% rate of surgical site infections (SSI). Few authors use the Center for Disease Control's (CDC) SSI definition for TE infections. We highlight how adoption of a consistent definition of TE infection may change how infections are researched, categorized, and ultimately managed. METHODS: Two researchers with definitional discrepancies of infection performed an independent analysis of all postmastectomy patients receiving TEs (n = 175) in 2017. RESULTS: Researcher One, using a clinical definition, delineated an infection rate of 19.4%. Antibiotics alone successfully treated 50% of cases. Researcher Two found an infection rate of 13.7% using CDC criteria. These infections were further delineated by a SSI rate of 6.3% and a TE infection rate post port access of 7.4%. Only 45.5% SSI's and 15.4% of TE infections were salvaged with antibiotics alone. CONCLUSIONS: Rigorous adoption of CDC criteria for infection characterization in published research will help standardize the definition of infection and allow surgeons to create evidence-based infection prevention regimens.

Gross Motor Function Classification System Specific Growth Charts-Utility as a Risk Stratification Tool for Surgical Site Infection Following Spine Surgery.

BACKGROUND: There is currently minimal evidence that preoperative malnutrition increases surgical site infection (SSI) risk in children with cerebral palsy (CP) undergoing spinal deformity surgery. Growth charts specifically for patients with CP have been created to aid in the clinical interpretation of body mass index (BMI) as a marker of nutritional status, but to our knowledge these charts have never been used to risk stratify patients before orthopaedic surgery. We hypothesize that patients with CP who have BMI-for-age below the 10th percentile (BMI≤10) on CP-specific growth charts are at increased risk of surgical site infection following spinal deformity surgery compared with patients with BMI-for-age above the 10th percentile (BMI>10). METHODS: Single-center, retrospective review comparing the rate of SSI in patients with CP stratified by BMI-for-age percentiles on CP-specific growth charts who underwent spinal deformity surgery. Odds ratios with 95% confidence intervals and Pearson χ tests were used to analyze the association of the measured nutritional indicators with SSI. RESULTS: In total, 65 patients, who underwent 74 procedures, had complete follow-up data and were included in this analysis. Ten patients (15.4%) were GMFCS I-III and 55 (84.6%) were GMFCS IV-V; 39 (60%) were orally fed and 26 (40%) were tube-fed. The rate of SSI in this patient population was 13.5% with 10 SSIs reported within 90 days of surgery. There was a significant association between patients with a BMI below the 10th percentile on GMFCS-stratified growth charts and the development of SSI (OR, 13.6; 95% CI, 2.4-75.4; P=0.005). All SSIs occurred in patients that were GMFCS IV-V. There was no association between height, weight, feeding method, or pelvic instrumentation and development of SSI. CONCLUSIONS: CP-specific growth charts are useful tools for identifying patients at increased risk for SSI following spinal instrumentation procedures, whereas standard CDC growth charts are much less sensitive. There is a strong association between preoperative BMI percentile on GMFCS-stratified growth charts and SSI following spinal deformity surgery. LEVEL OF EVIDENCE: Level III-Retrospective Study.

A Robust AUC Maximization Framework With Simultaneous Outlier Detection and Feature Selection for Positive-Unlabeled Classification.

The positive-unlabeled (PU) classification is a common scenario in real-world applications such as healthcare, text classification, and bioinformatics, in which we only observe a few samples labeled as "positive" together with a large volume of "unlabeled" samples that may contain both positive and negative samples. Building robust classifiers for the PU problem is very challenging, especially for complex data where the negative samples overwhelm and mislabeled samples or corrupted features exist. To address these three issues, we propose a robust learning framework that unifies area under the curve maximization (a robust metric for biased labels), outlier detection (for excluding wrong labels), and feature selection (for excluding corrupted features). The generalization error bounds are provided for the proposed model that give valuable insight into the theoretical performance of the method and lead to useful practical guidance, e.g., to train a model, we find that the included unlabeled samples are sufficient as long as the sample size is comparable to the number of positive samples in the training process. Empirical comparisons and two real-world applications on surgical site infection (SSI) and EEG seizure detection are also conducted to show the effectiveness of the proposed model.

[Peritoneal dialysis-related infections in pediatric patients: diagnosis and treatment review]. / Infecciones asociadas a diálisis peritoneal en el paciente pediátrico: diagnóstico y tratamiento.

Peritoneal dialysis-related infections are the main complication in pediatric patients undergoing this renal replacement therapy, associating a high rate of morbidity, generating also a decreasing survival of the peritoneal membrane and worsening the patient outcome. We describe the recommended diagnostic and therapeutic modalities to treat dialysis-related in children.

Infecciones asociadas a diálisis peritoneal en el paciente pediátrico: diagnóstico y tratamiento / Peritoneal dialysis-related infections in pediatric patients: diagnosis and treatment review

Resumen Las infecciones asociadas a diálisis peritoneal (DP), corresponden a la principal complicación de los pacientes pediátricos en esta terapia de reemplazo renal, disminuyendo la sobrevida de la membrana peritoneal y empeorando el pronóstico del paciente. El reconocimiento precoz y un tratamiento oportuno de éstas son fundamentales para preservar esta modalidad dialítica. Se presenta una revisión actualizada de la literatura científica, con el fin de entregar recomendaciones reproducibles en los distintos centros pediátricos que realizan diálisis peritoneal crónica en niños.

Peritoneal dialysis-related infections are the main complication in pediatric patients undergoing this renal replacement therapy, associating a high rate of morbidity, generating also a decreasing survival of the peritoneal membrane and worsening the patient outcome. We describe the recommended diagnostic and therapeutic modalities to treat dialysis-related in children.

International survey among orthopaedic trauma surgeons: Lack of a definition of fracture-related infection.

INTRODUCTION: Fracture-related infection (FRI) is one of the most challenging musculoskeletal complications in orthopaedic-trauma surgery. Although the orthopaedic community has developed and adopted a consensus definition of prosthetic joint infections (PJI), it still remains unclear how the trauma surgery community defines FRI in daily clinical practice or in performing clinical research studies. The central aim of this study was to survey the opinions of a global network of trauma surgeons on the definitions and criteria they routinely use, and their opinion on the need for a unified definition of FRI. The secondary aims were to survey their opinion on the utility of currently used definitions that may be at least partially applicable for FRI, and finally their opinion on the important clinical parameters that should be considered as diagnostic criteria for FRI. METHODS: An 11-item questionnaire was developed to cover the above-mentioned aims. The questionnaire was administered by SurveyMonkey and was sent via blast email to all registered users of AO Trauma (Davos, Switzerland). RESULTS: Out of the 26'563 recipients who opened the email, 2'327 (8.8%) completed the questionnaire. Nearly 90% of respondents agreed that a consensus-derived definition for FRI is required and 66% of the surgeons also agreed that PJI and FRI are not equal with respect to diagnosis, treatment and outcome. Furthermore, "positive cultures from microbiology testing", "elevation of CRP", "purulent drainage" and "local clinical signs of infection" were voted the most important diagnostic parameters for FRI. CONCLUSION: This international survey infers the need for a consensus definition of FRI and provides insight into the clinical parameters seen by an international community of trauma surgeons as being critical for defining FRI.

ICS classification system of infected osteosynthesis: Long-term results.

The best treatment strategy for infected osteosyntheses is still debated. While hardware removal or eventually early device exchange may be necessary in most of the cases, temporary hardware retention until fracture healing can be a valid alternative option in others. Aim of the present study is to report the long-term results of 215 patients with infected osteosyntheses, treated according to the ICS (Infection, Callus, Stability) classification in two Italian hospitals. Patients classified as ICS Type 1 (N = 83) feature callus progression and hardware stability, in spite of the presence of infection; these patients were treated with suppressive antibiotic therapy coupled with local debridement in 18.1% of the cases, and no hardware removal until bone healing. Type 2 patients (N = 75) are characterized by the presence of infection and hardware stability, but no callus progression; these patients were treated as Type 1 patients, but with additional callus stimulation therapies. Type 3 patients (N = 57), showing infection, no callus progression and loss of hardware stability, underwent removal and exchange of the fixation device. Considering only the initial treatment, performed according to the ICS classification, at a minimum 5 years follow up, 89.3% achieved bone healing and 93.5% did not show infection recurrence. The ICS classification appears as a useful and reliable tool to help standardizing the decision-making process in treating infected osteosynthesis with the most conservative approach.

Definition of infection after fracture fixation: A systematic review of randomized controlled trials to evaluate current practice.

INTRODUCTION: One of the most challenging musculoskeletal complications in modern trauma surgery is infection after fracture fixation (IAFF). Although infections are clinically obvious in many cases, a clear definition of the term IAFF is crucial, not only for the evaluation of published research data but also for the establishment of uniform treatment concepts. The aim of this systematic review was to identify the definitions used in the scientific literature to describe infectious complications after internal fixation of fractures. The hypothesis of this study was that the majority of fracture-related literature do not define IAFF. MATERIAL AND METHODS: A comprehensive search was performed in Embase, Cochrane, Google Scholar, Medline (OvidSP), PubMed publisher and Web-of-Science for randomized controlled trials (RCTs) on fracture fixation. Data were collected on the definition of infectious complications after fracture fixation used in each study. Study selection was accomplished through two phases. During the first phase, titles and abstracts were reviewed for relevance, and the full texts of relevant articles were obtained. During the second phase, full-text articles were reviewed. All definitions were literally extracted and collected in a database. Then, a classification was designed to rate the quality of the description of IAFF. RESULTS: A total of 100 RCT's were identified in the search. Of 100 studies, only two (2%) cited a validated definition to describe IAFF. In 28 (28%) RCTs, the authors used a self-designed definition. In the other 70 RCTs, (70%) there was no description of a definition in the Methods section, although all of the articles described infections as an outcome parameter in the Results section. CONCLUSION: This systematic review shows that IAFF is not defined in a large majority of the fracture-related literature. To our knowledge, this is the first study conducted with the objective to explore this important issue. The lack of a consensus definition remains a problem in current orthopedic trauma research and treatment and this void should be addressed in the near future.

Fracture-related infection: A consensus on definition from an international expert group.

Fracture-related infection (FRI) is a common and serious complication in trauma surgery. Accurately estimating the impact of this complication has been hampered by the lack of a clear definition. The absence of a working definition of FRI renders existing studies difficult to evaluate or compare. In order to address this issue, an expert group comprised of a number of scientific and medical organizations has been convened, with the support of the AO Foundation, in order to develop a consensus definition. The process that led to this proposed definition started with a systematic literature review, which revealed that the majority of randomized controlled trials in fracture care do not use a standardized definition of FRI. In response to this conclusion, an international survey on the need for and key components of a definition of FRI was distributed amongst all registered AOTrauma users. Approximately 90% of the more than 2000 surgeons who responded suggested that a definition of FRI is required. As a final step, a consensus meeting was held with an expert panel. The outcome of this process led to a consensus definition of FRI. Two levels of certainty around diagnostic features were defined. Criteria could be confirmatory (infection definitely present) or suggestive. Four confirmatory criteria were defined: Fistula, sinus or wound breakdown; Purulent drainage from the wound or presence of pus during surgery; Phenotypically indistinguishable pathogens identified by culture from at least two separate deep tissue/implant specimens; Presence of microorganisms in deep tissue taken during an operative intervention, as confirmed by histopathological examination. Furthermore, a list of suggestive criteria was defined. These require further investigations in order to look for confirmatory criteria. In the current paper, an overview is provided of the proposed definition and a rationale for each component and decision. The intention of establishing this definition of FRI was to offer clinicians the opportunity to standardize clinical reports and improve the quality of published literature. It is important to note that the proposed definition was not designed to guide treatment of FRI and should be validated by prospective data collection in the future.