Efficacy of magnetic resonance imaging in diagnosing osteomyelitis in diabetic foot ulcers

Predictive Factors for Limb Salvage and Foot Ulcer Recurrence in Patients with Chronic Limb-Threatening Ischemia After Multidisciplinary Team Treatment: A 6-Year Japanese Single-Center Study

Chronic limb-threatening ischemia (CLTI) is associated with a short-term risk of limb loss. Multidisciplinary teams are often involved in CLTI treatment; however, in Asian countries, multidisciplinary teams that include podiatrists specializing in foot wounds and vascular surgeons who can perform distal bypass surgery are lacking. We investigated predictive factors for limb salvage and foot ulcer recurrence in patients with CLTI treated by a Japanese single-center intensive multidisciplinary team over 6 years. We retrospectively investigated 84 patients with CLTI and foot ulcers who had undergone revascularization and wound treatment between October 2013 and December 2019. Following postrevascularization treatment, including undertaking minor amputations, the healing rate was 77.8%, and the average wound healing time was 75 ± 68 days. To achieve adequate blood supply, 17.7% of patients were treated using a combination of endovascular revascularization and bypass surgeries. Thirty-three (44%) patients had wound recurrence and there was wound recurrence within 6 months in 58.9% of these patients. Multivariate logistic regression analysis showed that postrevascularization skin perfusion pressure was significantly associated with wound healing (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.033-1.243, P = .0078). Diabetes mellitus (OR 9.72, 95% CI 1.855-50.937, P = .0071), and heart disease (OR 3.51, 95% CI 1.052-11.693, P = .0411) were significantly associated with wound recurrence (P < .05). Treatment within a single-center intensive multidisciplinary team resulted in good patient outcomes. Our study indicates that the revascularization endpoint of CLTI treatment should be marked by attainment of adequate blood supply and wound healing. The timing of revascularization and debridement is of utmost importance for the successful treatment of CLTI wounds.

Minimally invasive nanomedicine: nanotechnology in photo-/ultrasound-/radiation-/magnetism-mediated therapy and imaging

Traditional treatments such as chemotherapy and surgery usually cause severe side effects and excruciating pain. The emergence of nanomedicines and minimally invasive therapies (MITs) has brought hope to patients with malignant diseases. Especially, minimally invasive nanomedicines (MINs), which combine the advantages of nanomedicines and MITs, can effectively target pathological cells/tissues/organs to improve the bioavailability of drugs, minimize side effects and achieve painless treatment with a small incision or no incision, thereby acquiring good therapeutic effects. In this review, we provide a comprehensive review of the research status and challenges of MINs, which generally refers to the medical applications of nanotechnology in photo-/ultrasound-/radiation-/magnetism-mediated therapy and imaging. Additionally, we also discuss their combined application in various fields including cancers, cardiovascular diseases, tissue engineering, neuro-functional diseases, and infectious diseases. The prospects, and potential bench-to-bedside translation of MINs are also presented in this review. We expect that this review can inspire the broad interest for a wide range of readers working in the fields of interdisciplinary subjects including (but not limited to) chemistry, nanomedicine, bioengineering, nanotechnology, materials science, pharmacology, and biomedicine.

Diagnosing Osteomyelitis: A Histology Guide for Pathologists

Histopathologic examination of bone specimens coupled with bone culture is considered the gold standard for the diagnosis of osteomyelitis (OM). Despite this, studies have demonstrated interpathologist agreement in the diagnosis of OM as low as 30%, largely stemming from a lack of specific definitions and diagnostic criteria. Review of the literature has provided insight into the lifecycle of OM, illustrating the histologic progression of OM phases from acute to chronic, and provides support for defining subcategories of OM. Using an algorithmic histopathologic tool consisting of 15 criteria, each with an associated score, we defined 5 categories of OM: (1) acute OM, (2) acute and chronic OM, (3) chronic OM, (4) chronic active OM, and (5) chronic inactive OM. We reviewed 462 microscopic slides from 263 patients with suspected OM, and for each slide, we determined an algorithm-derived diagnosis, which was then used to calculate a total histopathologic load score (Jupiter score). Algorithm-derived diagnoses recapitulated original clinical diagnoses and diagnosed cases as OM that had not been originally diagnoses. These novel cases were more likely to have subsequent clinical complications. Finally, pathologic load scores were assessed for association with the category of OM.

Reevaluating Magnetic Resonance Imaging in Radiographically Suspected Osteomyelitis of the Toe

BACKGROUND:

Magnetic resonance imaging (MRI) is both sensitive and specific in the diagnosis of osteomyelitis, and it is an important imaging modality in preoperative planning of resection of infected bone. In many cases, however, the extent of osseous infection is evident on plain radiographs, and little additional information is gained from the MRI. The goal of this study was to assess the accuracy of radiographs against MRIs in assessing the spread of suspected osteomyelitis from one phalanx to another or to a metatarsal.

METHODS:

A medical record review was performed, and 14 patients with 16 toes confirmed to have osteomyelitis involving one or more phalanges were included in the study. An investigator blinded to the MRI findings interpreted the extent of osseous involvement based solely on the radiographic and clinical presentation. The accuracy of the radiographic interpretation was then calculated against the MRI findings.

RESULTS:

In 14 of the 16 toes (87.5%), whether osteomyelitis had spread from one bone to another was determined based on the radiographic and clinical presentation. In one toe, the radiograph did not adequately depict osteomyelitis in adjacent infected bone. In one more toe, the radiograph depicted features of osteomyelitis in uninfected bone.

CONCLUSIONS:

In a large percentage of patients, the phalanges affected by osteomyelitis had visible findings on the radiograph, and operative planning could have been based on the radiograph alone.

Follow up of MRI bone marrow edema in the treated diabetic Charcot foot - a review of patient charts

Background: Ill-defined areas of water-like signal on bone magnetic resonance imaging (MRI), characterized as bone marrow edema or edema-equivalent signal-changes (EESC), is a hallmark of active-stage pedal neuro-osteoarthropathy (Charcot foot) in painless diabetic neuropathy, and is accompanied by local soft-tissue edema and hyperthermia. The longitudinal effects on EESC of treating the foot in a walking cast were elucidated by reviewing consecutive cases of a diabetic foot clinic. Study design: Retrospective observational study, chart review Material and methods: Cases with active-stage Charcot foot were considered, in whom written reports on baseline and follow-up MRI studies were available for assessment. Only cases without concomitant infection or skin ulcer were chosen, in whom both was documented, onset of symptomatic foot swelling and patient compliance with cast treatment. Results: From 1994 to 2017, 45 consecutive cases in 37 patients were retrieved, with 95 MRI follow-up studies (1-6 per case, average interval between studies 13 weeks). Decreasing EESC was documented in 66/95 (69%) follow-up studies. However, 29/95 (31%) studies revealed temporarily increasing, migrating or stagnating EESC. Conclusion: EESC on MRI disappear in response to prolonged offloading and immobilizing treatment; however, physiologic as well as pathologic fluctuations of posttraumatic EESC have to be considered when interpreting the MR images. Conventional MRI is useful for surveillance of active-stage Charcot foot recovery.

Efficacy of a novel strategy for poststernotomy deep sternal infection after thoracic aorta replacement using a prosthetic graft

BACKGROUND

Poststernotomy deep sternal wound infections are persistent and occasionally fatal, especially in cases involving prosthetic grafts, because of their complicated structure and virtual impossibility of removal. We aimed to verify the influence of cooperation with plastic surgeons and our novel strategy for treating deep sternal wound infection after aortic replacement on cardiovascular surgery outcomes.

PATIENTS AND METHODS

Nine hundred eighty-three consecutive patients were divided into two groups: an early group (2012-2013) and a late group (2014-2015). The late group had received cooperatively improved perioperative wound management: our novel strategy of deep sternal infection based on radical debridement and immediate reconstruction decided by reference to severities of the patient's general condition and widespread infection by early intervention of plastic surgeons. The groups were analysed retrospectively. Binary variables were analysed statistically with the Fisher exact test and continuous variables with the Mann-Whitney U test. Inter-group differences were assessed with the chi-square test.

RESULTS

Twenty of 390 cases in the early group and 13 of 593 cases in the late group were associated with deep sternal infection. Morbidity rates of deep sternal wound infection and associated mortality rates 1 year after reconstruction surgery were significantly less (p <0.05 for both) in the late group.

CONCLUSIONS

Intervention by plastic surgeons improved perioperative wound management outcomes. Our treatment strategy for deep sternal wound infection also reduced associated mortality rates. Facilities should consider the early inclusion of plastic surgeons in the treatment of patients undergoing aortic replacement to facilitate better outcomes.

Correlating pre-operative MRI measurements of metatarsal Osteomyelitis with surgical clean margins reveals the need for a one centimeter resection margin

Background

Due to the high incidence of forefoot ulcerations with associated osteomyelitis, there has been an increased demand for partial ray amputations. In order to ensure complete removal of infected metatarsal bone, a clean margin amount is chosen based on the surgeon’s intraoperative visual subjective evaluation. The margin is resected and sent to pathology. Currently the literature shows positive proximal margin rates of 35–40%. The purpose of this study was to reduce the rate of positive proximal margins by effectively resecting all infected bone using pre-operative MRI measurements with an added resection margin.

Methods

Twenty-four osteomyelitis positive metatarsals were included in this exploratory study. The distance of proximal osteomyelitic extension within the metatarsal was measured on MRI in centimeters. Intra-operatively, the partial ray amputation cut was determined by adding an extra 0.5 cm resection margin to the MRI measurement. At the study’s mid-point, bone histopathology revealed an increase in positive proximal margin rates-so the resection margin was increased to 1 cm. Descriptive outcomes included the mean distance of osteomyelitis propagation, proximal margin rates, as well as diagnostic statistics.

Results

After removing the specimens with false positive MRI results, the study sample included 21 metatarsals positive for osteomyelitis. A 0.5 cm resection margin proximal to the osteomyelitis resulted in a 50% positive proximal margin rate. After increasing the resection margin to 1 cm, there was found to be an improved positive proximal margin rate of 9%. Based on MRI findings, the mean distance + standard deviation of osteomyelitis propagation along the metatarsal proximally was 1.81 cm + 0.74 cm. The metatarsal specimen was processed by pathology into multiple pieces and compared to MRI, resulting in MRI sensitivity of 67%, specificity of 74%, positive predictive value of 79%, and negative predictive value of 60%.

Conclusions

By performing a 1 cm resection margin proximal to the metatarsal osteomyelitis the proximal margin rate was reduced to clinically meaningful levels. These preliminary findings support using a 1 cm resection margin when performing any form of metatarsal amputation, to reduce the risk of residual osteomyelitis post-operatively.

Trial registration

St. Luke’s Hospital, IRB National Protocol ID SLHN2015–112. Date:1–13-16.

Surgical treatment strategy for diabetic forefoot osteomyelitis

The aim of this study was to propose an appropriate surgical treatment for diabetic forefoot osteomyelitis (DFO) involving ischemia or moderate to severe soft tissue infection. The records of 28 patients with osteomyelitis from 2009 to 2015 were retrospectively studied. All patients had undergone surgery based on preoperative magnetic resonance imaging examinations and histopathological or culture analyses confirming the surgical bone margin. The appropriate surgical margin, crucial factors for early healing, and prognosis after complete resection of osteomyelitis were examined. After healing, patients were followed up to assess prognosis (range 32-1,910 days, median 546 days). The healing rate of nonischemic cases of DFO with negative surgical margins was 100% and that of ischemic cases was 84.6%; the ambulatory rates for both types of cases were 100%. No wound (and/or osteomyelitis) recurrence was observed. Nine new cases of DFO developed in six patients (21.4%; eight were due to vascular stenosis, and one was due to biomechanical changes in the foot. After complete resection of osteomyelitis, preoperative and postoperative C-reactive protein levels and the size of the ulcer were significant predictors of early healing (p < 0.05, 0.01, and 0.05, respectively). The appropriate surgical margin should be set in the area of bone marrow edema, based on magnetic resonance imaging examinations after revascularization. In cases with high preoperative or postoperative C-reactive protein levels, long-term antibiotic therapy is recommended, and surgery should be planned after the C-reactive protein levels decrease, except in emergencies.

Saving the Limb in Diabetic Patients With Ischemic Foot Lesions Complicated by Acute Infection

Ischemia and infection are the most important factors affecting the prognosis of foot ulcerations in diabetic patients. To improve the outcome of these patients, it is necessary to aggressively treat 2 important pathologies—namely, occlusive arterial disease affecting the tibial and femoral arteries and infection of the ischemic diabetic foot. Each of these 2 conditions may lead to major limb amputation, and the presence of both critical limb ischemia (CLI) and acute deep infection is a major risk factor for lower-extremity amputation. Thus, the management of diabetic foot ulcers requires specific therapeutic approaches that vary significantly depending on whether foot lesions are complicated by infection and/or ischemia. A multidisciplinary team approach is the key to successful treatment of a diabetic foot ulcer: ischemic diabetic foot ulcers complicated by acute deep infection pose serious treatment challenges because high levels of skill, organization, accuracy, and timing of intervention are required to maximize the chances of limb salvage: these complex issues are better managed by a multidisciplinary clinical group.