The utility of bone scintigraphy with SPECT/CT in the evaluation and management of frostbite injuries

Frostbite in the Pediatric Population: A Comprehensive Review and a Prospective Canadian Survey

INTRODUCTION

Frostbite in the pediatric population, where skeletal maturity has not been achieved, can have important repercussions on subsequent growth. Yet, the optimal management of frostbite injuries in children remains vague. This review aims to summarize the current evidence for frostbite management in children and understand Canadian practice trends on this topic.

METHODS

A review using Medline, Scopus, Web of Science, and gray literature was performed to identify relevant literature on the clinical manifestations, diagnostic methods, and treatment options in pediatric frostbite. An online survey was sent to plastic surgeons through the Canadian Society of Plastic Surgeons (CSPS) mailing list to further identify national practices and trends for pediatric frostbite management.

RESULTS

A total of 109 articles were reviewed. No article provided a specific algorithm for pediatric frostbite, with existing recommendations suggesting the use of adult guidelines for treating children. Our survey yielded 9 responses and highlighted the rarity of pediatric frostbite cases, with no responder treating more than 10 cases per year. Most (55.6%) do not use a pediatric-specific treatment algorithm, whereas 30% apply adult guidelines. A conservative approach focusing on rewarming (55.6%), limb elevation (50%), and tetanus status verification (66.7%) was predominant. Imaging and surgical interventions seem to be reserved for severe cases.

CONCLUSIONS

The current literature for pediatric frostbite management lacks specificity. Canadian practices vary, with a trend toward a conservative approach. The limited evidence and rarity of experience highlight the need for further research, ideally in a collaborative multicentric manner, to create a consensus for pediatric frostbite care.

Cold Injury

Cold injury has been documented for centuries and remains a concern for military personnel, winter recreationalists, and urban homeless populations. Treatment advances in the last decades have included thrombolytic and prostaglandin therapies however the mainstay remains early recognition and rapid rewarming. This chapter focuses on frostbite, with a brief overview of other cold related conditions.

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Frostbite: 2024 Update

The Wilderness Medical Society convened an expert panel to develop a set of evidence-based guidelines for the prevention and treatment of frostbite. We present a review of pertinent pathophysiology. We then discuss primary and secondary prevention measures and therapeutic management. Recommendations are made regarding each treatment and its role in management. These recommendations are graded on the basis of the quality of supporting evidence and balance between the benefits and risks or burdens for each modality according to methodology stipulated by the American College of Chest Physicians. This is an updated version of the guidelines published in 2019.

Bone scintigraphy outperformed anatomic images in frostbite injuries: a case report

Frostbite is a localized cold thermal injury, as a result of tissue exposure to temperatures below freezing point for a prolonged period of time. The spectrum of injury is broad; thus, frostbite injuries may have deleterious effects with the possibility of losing part or whole extremities. We aim to present the case of a 38-year-old male patient evaluated with multiphase technetium-99m-methylene diphosphonate bone scintigraphy. This methodology may accelerate clinical management of frostbite injuries because it provides precise clinical-imaging correlation by determining the extent of injury and can accurately predict the level of amputation if required.

Practical Review of the Current Management of Frostbite Injuries

Frostbite is an injury that occurs when the skin and tissues are exposed to temperatures below their freezing point. This type of injury can lead to various complications such as functional loss, chronic pain, and psychological trauma. As such, understanding frostbite management is crucial for optimal patient care. A scoping review was conducted in February 2022 using PubMed, EMBASE, referenced articles and snowballing to identify relevant published articled using the terms "frostbite" and "management" and "surgery. Articles related to pathophysiology, classifications, radiography, complications, and medical and surgical management were included to formulate recommendations for practical management. Two hundred fifty-one articles were identified and 54 met inclusion criteria. Rapid rewarming in warm water (40-42 °C) remains the standard of care. Thrombolytic therapy has been shown in numerous studies to improve tissue salvage. Radiographic imaging has become crucial in the evaluation and management in frostbite injury. Current literature recommends delayed surgery with soft tissue debridement and bone scan-guided amputations. Surgical intervention including debridement, selective blister drainage, fasciotomies, surgical salvage, skin grafts' and flaps are often necessary in these patients towards optimizing form and function. The true prevalence and incidence of frostbite injury is unknown. A centralized national database will improve our understanding of the diagnostic and management modalities used in frostbite care. Plastic surgeons have a critical role in the management of frostbite care and must work with an interdisciplinary team to identify the best treatment route for optimal patient care.

The Effects Of Rapid Rewarming On Tissue Salvage In Severe Frostbite Injury

Frostbite is a high morbidity injury caused by soft tissue freezing, which can lead to digit necrosis requiring amputation. Rapid rewarming is a first line treatment method that involves placing affected digits into a warm water bath. This study aims to assess the clinical practices for frostbite at facilities outside of dedicated burn centers, and any impact these practices have on tissue salvage. Retrospective chart review at a single burn center identified frostbite patients admitted directly or as transfers over a seven-year period. Records were reviewed to identify initial treatment strategies. If given, time to thrombolytics from admit was noted. Tissue salvage rates were calculated from radiologically derived tissue at-risk scores and final amputation scores. One-hundred patients were transferred from outside facilities, and 108 were direct admissions (N=208). There was no significant difference in group demographics. Rapid rewarming was the initial treatment modality more commonly in direct admit patients (P=0.016). The use of rapid rewarming did not correlate with tissue salvage (P=0.112). Early use of thrombolytics had a positive impact on tissue salvage (P=0.003). Thrombolytics were given 1.2 hours earlier in direct admit patients (P=0.029), however there was no difference in tissue salvage rates between the groups (P=0.127). Efforts should focus on larger scale study to further assess the effectiveness of rapid rewarming. Although rapid rewarming did not significantly impact tissue salvage in this study, we continue to recommend its use over less studied treatment methods, and continue to view it as an important bridge to burn center transfer and administration of thrombolytic therapy.

Research progress in the pathogenic mechanisms and imaging of severe frostbite

PURPOSE

This article reviews the pathological mechanisms and progress of imaging of severe frostbite to assist in the search for targets for clinical diagnosis and treatment of severe frostbite. This review also aims to provide strong evidence for clinical diagnosis and treatment of deep frostbite.

METHODS

The review was based on the summary and analysis of the existing literature, and explored the pathological mechanism of deep frostbite and the advantages and disadvantages of imaging diagnostic methods.

RESULTS

According to the depth of tissue involvement, frostbite is divided into 4 levels. Severe frostbite includes Grade 3 and Grade 4 frostbite. Clinical performance evaluation and imaging diagnostic research have always been the mainstream of severe frostbite diagnosis. Imaging methods focus on vascular patency and tissue vitality. This article introduces angiography, SETCT/CT and MRA, and we summarize the advantages and disadvantages of these imaging methods. We recommend corresponding imaging modalities according to the state of frostbite patients.

CONCLUSIONS

Imaging examination, especially angiography and bone scans, provide useful information for determining the diagnosis and prognosis of severe frostbite. In order to obtain a good clinical prognosis, clinicians should first perform SPECT/CT. MRA does not burden the patient's body, but the balance between cost and benefit must be considered. Angiography provides a good feedback on the changes in blood vessel status before and after treatment, which is helpful for discovering the response of limbs to treatment.

A Longitudinal Study of T2 Mapping Combined With Diffusion Tensor Imaging to Quantitatively Evaluate Tissue Repair of Rat Skeletal Muscle After Frostbite

Purpose: T2 mapping and diffusion tensor imaging (DTI) enable the detection of changes in the skeletal muscle microenvironment. We assessed T2 relaxation times, DTI metrics, performed histological characterization of frostbite-induced skeletal muscle injury and repair, and provided diagnostic imaging biomarkers.

Design and Methods: Thirty-six Sprague Dawley rats (200 ± 10 g) were obtained. Thirty rats were used for establishing a skeletal muscle frostbite model, and six were untreated controls. Functional MR sequences were performed on rats on days 0, 3, 5, 10, and 14 (n = 6 per time point). Rats were then sacrificed to obtain the quadriceps muscles. Tensor eigenvalues (λ1, λ2, and λ3), mean diffusivity (MD), fractional anisotropy (FA), and T2 values were compared between the frostbite model and control rats. ImageJ was used to measure the extracellular area fraction (EAF), muscle fiber cross-sectional area (fCSA), and skeletal muscle tumor necrosis factor α (TNF-α), and Myod1 expression. The correlation between the histological and imaging parameters of the frostbitten skeletal muscle was evaluated. Kolmogorov–Smirnoff test, Leven’s test, one-way ANOVA, and Spearman coefficient were used for analysis.

Results: T2 relaxation time of frostbitten skeletal muscle was higher at all time points (p < 0.01). T2 relaxation time correlated with EAF, and TNF-α and Myod1 expression (r = 0.42, p < 0.05; r = 0.86, p < 0.01; r = 0.84, p < 0.01). The average tensor metrics (MD, λ1, λ2, and λ3) of skeletal muscle at 3 and 5 days of frostbite increased (p < 0.05), and fCSA correlated with λ1, λ2, and λ3, and MD (r = 0.65, p < 0.01; r = 0.48, p < 0.01; r = 0.52, p < 0.01; r = 0.62, p < 0.01).

Conclusion: T2 mapping and DTI imaging detect frostbite-induced skeletal muscle injury early. This combined approach can quantitatively assess skeletal muscle repair and regeneration within 2 weeks of frostbite. Imaging biomarkers for the diagnosis of frostbite were suggested.

Protocoled thrombolytic therapy for frostbite improves phalangeal salvage rates

Background

Frostbite is a cold injury that has the potential to cause considerable morbidity and long-term disability. Despite the complexity of these patients, diagnostic and treatment practices lack standardization. Thrombolytic therapy has emerged as a promising treatment modality, demonstrating impressive digit salvage rates. We review our experience with thrombolytic therapy for severe upper extremity frostbite.

Methods

Retrospective data on all frostbite patients evaluated at our institution from December 2017 to March 2018 was collected. A subgroup of patients with severe frostbite treated with intra-arterial thrombolytic therapy (IATT) were analysed.

Results

Of the 17 frostbite patients treated at our institution, 14 (82%) were male and the median age was 31 (range: 19–73). Substance misuse was involved in a majority of the cases (58.8%). Five (29.4%) patients with severe frostbite met inclusion criteria for IATT and the remaining patients were treated conservatively. Angiography demonstrated a 74.5% improvement in perfusion after tissue plasminogen activator thrombolysis. When comparing phalanges at risk on initial angiography to phalanges undergoing amputation, the phalangeal salvage rate was 83.3% and the digit salvage rate was 80%. Complications associated with IATT included groin hematoma, pseudoaneurysm and retroperitoneal hematoma.

Conclusions

Thrombolytic therapy has the potential to greatly improve limb salvage and functional recovery after severe frostbite when treated at an institution that can offer comprehensive, protocoled thrombolytic therapy. A multi-center prospective study is warranted to elucidate the optimal treatment strategy in severe frostbite.

Utilization of bone scan and single photon emission computed tomography on amputation planning in acute microvascular injury: Two cases

The use of single photon emission computer tomography (SPECT/CT) in acute vascular injury is not well documented. SPECT/CT combines the anatomic detail of computer tomography with the functional vascular perfusion of photon emission to determine the viability of osseous structures and surrounding soft tissue. The superimposed imaging provides the practitioner with a reliable anatomic image of viability of a specific anatomic area following insult or injury. We present two cases, bilateral lower extremity frostbite, and symmetric peripheral gangrene in which this imaging modality provided guidance for surgical intervention with adequate predictability and results.