Nuclear imaging for diagnosing fracture-related infection

Purpose Fracture-related infection (FRI) is a complication of surgical fracture treatment and can be challenging to diagnose. Recent studies show promising results for the use of either FDG-PET/CT or WBC/anti-granulocyte scintigraphy. The purpose of this pictorial essay is to outline recent developments in nuclear imaging techniques to diagnose FRI. Methods The current literature on this topic is reviewed. Additionally, three examples of patients who underwent nuclear imaging as part of their clinical work-up and surgical treatment for FRI are presented. Results Based on recent retrospective studies, FDG-PET/CT (accuracy 0.83) and WBC scintigraphy with SPECT/CT (accuracy 0.92) both have a good diagnostic accuracy for diagnosing fracture-related infection. Nuclear imaging contributes to a correct diagnosis in patients with FRI. Conclusion Retrospective studies show promising results for both FDG-PET/CT and WBC scintigraphy with SPECT/CT in diagnosing FRI. A prospective, multicenter study (IFI trial), directly comparing MRI, FDG-PET/CT, and WBC scintigraphy with SPECT/CT in patients with suspected FRI, is currently in progress

High delayed and missed injury rate after inter-hospital transfer of severely injured trauma patients

PURPOSE: Missed injuries are reported in 1.3-65% of all admitted trauma patients. The severely injured patient that needs a higher level of care which requires an inter-hospital transfer has an increased risk for missed injuries. The aim of this study was to establish the incidence and clinical relevance of missed injuries in severely injured patients who require inter-hospital transfer to a level 1 trauma center. METHODS: All patients with an Injury Severity Score (ISS) ≥ 16 transferred to the University Medical Center Groningen (UMCG) between January 2010 and July 2015 were included. Data were obtained from a prospective trauma database and supplemented with information from the patient records. A delayed diagnosis was defined as any injury detected within the first 24 h after the initial trauma, with or without a tertiary survey. Missed diagnoses were defined as any injury diagnosed after 24 h following trauma. RESULTS: Two hundred and fifty-one trauma patients were included. A total of 88 patients (35%) were found to have ≥ 1 new diagnoses with 65 (26%) patients that had 1 or more delayed diagnoses and 23 (9.2%) patients had 1 or more missed diagnoses (detected > 24 h after injury) after transfer to our hospital. For 47 of the 88 patients (53%), the new diagnoses required a change of management. The Glasgow Coma Scale (GCS) was the only statistically significant risk factor for a new diagnosis upon transfer. CONCLUSIONS: Inter-hospital transfer of severely injured patients increases the risk of a delayed detection of injuries. We found that 35% of all transferred patients with an ISS ≥ 16 have at least new diagnoses, with over half of these diagnoses requiring a change of management. Given these findings, clinicians should maintain a high index of suspicion when receiving a transferred severely injured trauma patient

White Blood Cell Scintigraphy for Fracture-Related Infection:Is Semiquantitative Analysis of Equivocal Scans Accurate?

Purpose: White blood cell (WBC) scintigraphy is considered the gold-standard nuclear imaging technique for diagnosing fracture-related infection (FRI). Correct interpretation of WBC scans in FRI is important since a false positive or false negative diagnosis has major consequences for the patient in terms of clinical decision-making. The European Association of Nuclear Medicine (EANM) guideline for correct analysis and interpretation of WBC scans recommends semiquantitative analysis of visually equivocal scans. Therefore, this study aims to assess the diagnostic accuracy of semiquantitative analysis of visually equivocal WBC scans for diagnosing FRI. Methods: A retrospective single-center study was performed in consecutive patients who received WBC scintigraphy in the diagnostic work-up for FRI between February 2012 and January 2017. All the visually equivocal scans were analysed using semiquantitative analysis by comparing leukocyte uptake in the manually selected suspected infection focus with the contralateral bone marrow (L/R ratio). Cut-off points for a ‘positive’ scan result of >0%, >10% and >20% leukocyte increase between the early and late scans were used in separate analyses. The discriminative ability was quantified by calculating the sensitivity, specificity and diagnostic accuracy. Results: In total, 153 WBC scans were eligible for inclusion. After visual assessment of all the scans, 28 visually equivocal scans were included. Dichotomization of the ratios using the cut-off of >0% resulted in a sensitivity of 30%, a specificity of 45% and a diagnostic accuracy of 40%. The >10% cut-off point resulted in a sensitivity of 18%, a specificity of 82% and a diagnostic accuracy of 66%. The >20% cut-off point resulted in a sensitivity of 0%, a specificity of 89% and a diagnostic accuracy of 67%. Conclusion: Semiquantitative analysis of visually equivocal WBC scans is insufficient for correctly diagnosing FRI

What is the diagnostic value of the Centers for Disease Control and Prevention criteria for surgical site infection in fracture-related infection?

Background: Fracture-related infection (FRI) remains one of the most challenging complications in orthopaedic trauma surgery. An early diagnosis is of paramount importance to guide treatment. The primary aim of this study was to compare the Centers for Disease Control and Prevention (CDC) criteria for the diagnosis of organ/space surgical site infection (SSI) to the recently developed diagnostic criteria of the FRI consensus definition in operatively treated fracture patients.   Methods: This international multicenter retrospective cohort study evaluated 257 patients with 261 infections after operative fracture treatment. All patients included in this study were considered to have an FRI and treated accordingly (‘intention to treat’). The minimum follow-up was one year. Infections were scored according to the CDC criteria for organ/space SSI and the diagnostic criteria of the FRI consensus definition.   Results: Overall, 130 (49.8%) FRIs were captured when applying the CDC criteria for organ/space SSI, whereas 258 (98.9%) FRIs were captured when applying the FRI consensus criteria. Patients could not be classified as having an infection according to the CDC criteria mainly due to a lack of symptoms within 90 days after the surgical procedure (n = 96; 36.8%) and due to the fact that the surgery was performed at an anatomical localization not listed in the National Healthcare Safety Network (NHSN) operative procedure code mapping (n = 37; 14.2%).    Conclusion: This study confirms the importance of standardization with respect to the diagnosis of FRI. The results endorse the recently developed FRI consensus definition. When applying these diagnostic criteria, 98.9% of the infections that occured after operative fracture treatment could be captured. The CDC criteria for organ/space SSI captured less than half of the patients with an FRI requiring treatment, and seemed to have less diagnostic value in this patient population

Diagnosing Fracture-Related Infection: Current Concepts and Recommendations

Summary:Fracture-related infection (FRI) is a severe complication after bone injury and can pose a serious diagnostic challenge. Overall, there is a limited amount of scientific evidence regarding diagnostic criteria for FRI. For this reason, the AO Foundation and the European Bone and Joint Infection Society proposed a consensus definition for FRI to standardize the diagnostic criteria and improve the quality of patient care and applicability of future studies regarding this condition. The aim of this article was to summarize the available evidence and provide recommendations for the diagnosis of FRI. For this purpose, the FRI consensus definition will be discussed together with a proposal for an update based on the available evidence relating to the diagnostic value of clinical parameters, serum inflammatory markers, imaging modalities, tissue and sonication fluid sampling, molecular biology techniques, and histopathological examination. Second, recommendations on microbiology specimen sampling and laboratory operating procedures relevant to FRI will be provided.Level of Evidence:Diagnostic Level V. See Instructions for Authors for a complete description of levels of evidence

General treatment principles for fracture-related infection: recommendations from an international expert group

Fracture-related infection (FRI) remains a challenging complication that creates a heavy burden for orthopaedic trauma patients, their families and treating physicians, as well as for healthcare systems. Standardization of the diagnosis of FRI has been poor, which made the undertaking and comparison of studies difficult. Recently, a consensus definition based on diagnostic criteria for FRI was published. As a well-established diagnosis is the first step in the treatment process of FRI, such a definition should not only improve the quality of published reports but also daily clinical practice. The FRI consensus group recently developed guidelines to standardize treatment pathways and outcome measures. At the center of these recommendations was the implementation of a multidisciplinary team (MDT) approach. If such a team is not available, it is recommended to refer complex cases to specialized centers where a MDT is available and physicians are experienced with the treatment of FRI. This should lead to appropriate use of antimicrobials and standardization of surgical strategies. Furthermore, an MDT could play an important role in host optimization. Overall two main surgical concepts are considered, based on the fact that fracture fixation devices primarily target fracture consolidation and can be removed after healing, in contrast to periprosthetic joint infection were the implant is permanent. The first concept consists of implant retention and the second consists of implant removal (healed fracture) or implant exchange (unhealed fracture). In both cases, deep tissue sampling for microbiological examination is mandatory. Key aspects of the surgical management of FRI are a thorough debridement, irrigation with normal saline, fracture stability, dead space management and adequate soft tissue coverage. The use of local antimicrobials needs to be strongly considered. In case of FRI, empiric broad-spectrum antibiotic therapy should be started after tissue sampling. Thereafter, this needs to be adapted according to culture results as soon as possible. Finally, a minimum follow-up of 12 months after cessation of therapy is recommended. Standardized patient outcome measures purely focusing on FRI are currently not available but the patient-reported outcomes measurement information system (PROMIS) seems to be the preferred tool to assess the patients’ short and long-term outcome. This review summarizes the current general principles which should be considered during the whole treatment process of patients with FRI based on recommendations from the FRI Consensus Group. Level of evidence: Level V

Accuracy of diagnostic imaging modalities for peripheral post-traumatic osteomyelitis : a systematic review of the recent literature

Aims: Post-traumatic osteomyelitis (PTO) is difficult to diagnose and there is no consensus on the best imaging strategy. The aim of this study is to present a systematic review of the recent literature on diagnostic imaging of PTO. Methods: A literature search of the EMBASE and PubMed databases of the last 16 years (2000–2016) was performed. Studies that evaluated the accuracy of magnetic resonance imaging (MRI), three-phase bone scintigraphy (TPBS), white blood cell (WBC) or antigranulocyte antibody (AGA) scintigraphy, fluorodeoxyglucose positron emission tomography (FDG-PET) and plain computed tomography (CT) in diagnosing PTO were considered for inclusion. The review was conducted using the PRISMA statement and QUADAS-2 criteria. Results: The literature search identified 3358 original records, of which 10 articles could be included in this review. Four of these studies had a comparative design which made it possible to report the results of, in total, 17 patient series. WBC (or AGA) scintigraphy and FDG-PET exhibit good accuracy for diagnosing PTO (sensitivity ranged from 50–100%, specificity ranged from 40–97% versus 83–100% and 51%–100%, respectively). The accuracy of both modalities improved when a hybrid imaging technique (SPECT/CT & FDG-PET/CT) was performed. For FDG-PET/CT, sensitivity ranged between 86 and 94% and specificity between 76 and 100%. For WBC scintigraphy + SPECT/CT, this is 100% and 89–97%, respectively. Conclusions: Based on the best available evidence of the last 16 years, both WBC (or AGA) scintigraphy combined with SPECT/CT or FDG-PET combined with CT have the best diagnostic accuracy for diagnosing peripheral PTO

Brodie's Abscess : A Systematic Review of Reported Cases

Introduction: Brodie's abscess is a form of osteomyelitis. Since its first appearance in the medical literature in 1832, numerous cases have been described. The aim of this article is to provide the first comprehensive overview of published cases of Brodie's abscess, and to describe diagnostic methods, therapeutic consequences and outcomes. Methods: According to PRISMA guidelines a systematic review of the literature was performed. All published data in English or Dutch were considered for inclusion with no limitations on publication date. Data was extracted on demography, duration of symptoms, signs of inflammation, diagnostic imaging, causative agent, treatment and follow-up. Results: A total of 70 articles were included, reporting on a total of 407 patients, mostly young (median age 17) males (male:female ratio 2.1:1). The median duration of symptoms before diagnosis was 12 weeks (SD 26). Mostly consisting of pain (98%) and/or swelling (53%). 84% of all patients were afebrile, and less than 50% had elevated serum inflammation markers. Diagnosis was made with a combination of imaging modalities: plain X-ray in 96%, MRI (16%) and CT-scan (8%). Treatment consisted of surgery in 94% of the cases, in conjunction with long term antibiotics in 77%. Staphylococcus aureus was the pathogen most often found in the culture (67,3%). Outcome was generally reported as favorable. Recurrence was reported in 15,6% of the cases requiring further intervention. Two cases developed permanent disability. Conclusion: Brodie's abscess has an insidious onset as systemic inflammatory signs and symptoms were often not found. Treatment consisted mostly of surgery followed by antibiotics (77%) or only surgery (17%) and outcomes were generally reported as favourable

Brodie's Abscess : A Systematic Review of Reported Cases

Introduction: Brodie's abscess is a form of osteomyelitis. Since its first appearance in the medical literature in 1832, numerous cases have been described. The aim of this article is to provide the first comprehensive overview of published cases of Brodie's abscess, and to describe diagnostic methods, therapeutic consequences and outcomes. Methods: According to PRISMA guidelines a systematic review of the literature was performed. All published data in English or Dutch were considered for inclusion with no limitations on publication date. Data was extracted on demography, duration of symptoms, signs of inflammation, diagnostic imaging, causative agent, treatment and follow-up. Results: A total of 70 articles were included, reporting on a total of 407 patients, mostly young (median age 17) males (male:female ratio 2.1:1). The median duration of symptoms before diagnosis was 12 weeks (SD 26). Mostly consisting of pain (98%) and/or swelling (53%). 84% of all patients were afebrile, and less than 50% had elevated serum inflammation markers. Diagnosis was made with a combination of imaging modalities: plain X-ray in 96%, MRI (16%) and CT-scan (8%). Treatment consisted of surgery in 94% of the cases, in conjunction with long term antibiotics in 77%. Staphylococcus aureus was the pathogen most often found in the culture (67,3%). Outcome was generally reported as favorable. Recurrence was reported in 15,6% of the cases requiring further intervention. Two cases developed permanent disability. Conclusion: Brodie's abscess has an insidious onset as systemic inflammatory signs and symptoms were often not found. Treatment consisted mostly of surgery followed by antibiotics (77%) or only surgery (17%) and outcomes were generally reported as favourable