An algorithm for early aggressive treatment of frostbite with limb salvage directed by triple-phase scanning

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

OBJECTIVE:

Frostbite is a localized cold-thermal injury resulting from prolonged exposure of flesh to freezing and near freezing temperatures. The depth and extent of frostbite injuries are not easily assessed, from a clinical standpoint, at the time of injury making it challenging to plan appropriate management and treatment.

METHODS:

A review of the literature of management of cold-related injuries and retrospective case review of the imaging and clinical course of frostbite injury.

RESULTS:

Bone scintigraphy with single photon emission computed tomography (SPECT)/CT was performed in the acute and subacute course of frostbite injuries, subsequently leading to earlier definitive management and shorter hospital stay.

CONCLUSION:

Multiphase technetium-99m-methylenediphosphonate (⁹⁹mTc-MDP) bone scintigraphy with SPECT/CT can expedite clinical management of frostbite injuries by determining the extent of injury and can accurately predict the level of amputation if needed.

ADVANCES IN KNOWLEDGE:

 SPECT/CT is underutilized at many facilities but can have a profound and immediate impact on clinical management of patients with frostbite when used in combination with physiological bone scan imaging.

Frostbite: Spectrum of Imaging Findings and Guidelines for Management

Frostbite is a localized cold thermal injury that results from tissue freezing. Frostbite injuries can have a substantial effect on long-term limb function and mobility if not promptly evaluated and treated. Imaging plays a critical role in initial evaluation of frostbite injuries and in monitoring response to treatment. A multimodality approach involving radiography, digital subtraction angiography (DSA), and/or multiphase bone scintigraphy with hybrid single photon emission computed tomography (SPECT)/computed tomography (CT) is often necessary for optimal guidance of frostbite care. Radiographs serve as an initial survey of the affected limb and may demonstrate characteristic findings, depending on the time course and severity of injury. DSA is used to evaluate perfusion of affected soft tissues and identify potential targets for therapeutic intervention. Angiography-directed thrombolysis plays an essential role in tissue preservation and salvage in deep frostbite injuries. Multiphase bone scintigraphy with technetium 99m-labeled diphosphonate provides valuable information regarding the status of tissue viability after initial treatment. The addition of SPECT/CT to multiphase bone scintigraphy enables precise anatomic localization of the level and depth of tissue necrosis before its appearance at physical examination and can help uncover subtle findings that may remain occult at scintigraphy alone. Multiphase bone scintigraphy with SPECT/CT is the modality of choice for prognostication and planning of definitive surgical care of affected limbs. Appropriate use of imaging to direct frostbite care can help limit the effects that these injuries have on limb function and mobility. ©RSNA, 2016.

Cold injury

The pathophysiology of true frostbite reveals that the direct injury produced during the initial freeze process has a minor contribution to the global tissue damage. However, rapid rewarming to reverse the tissue crystallization has essentially been the lone frostbite intervention for almost half a century. The major pathologic process is the progressive microvascular thrombosis following reperfusion of the ischemic limb, with the cold-damaged endothelial cells playing a central role in the outcome of these frozen tissues. Newer interventions offer the opportunity to combat this process, and this article offers a scientific approach to frostbite injuries of the upper extremities.

Environmental Cold-Induced Injury

More than 650 deaths from hypothermia occur each year in the United States. Even minor deviation from normal temperature leads to important symptoms and disability. The most significant risk factors are advanced age, mental impairment, substance abuse, and injury. This article examines the incidence of hypothermia, its detrimental effect on trauma patients, and methods of rewarming the hypothermic patient. It also looks at the controversial protective role hypothermia might play in shock, organ transplantation, cardiac arrest, and brain injury. Finally, it examines cold injuries, including frostbite, chilblain, and trench foot, and makes recommendations for their treatment.

Retrospective study of 70 cases of severe frostbite lesions: a proposed new classification scheme

OBJECTIVE

Previous frostbite classifications were mainly based on retrospective diagnosis and, most of the time, could not be used to predict the final outcome of the lesions and especially the probability of an amputation and its level. The aim of this study was to suggest a new classification at day 0 based mainly on the topography of the lesions and on early bone scan results, which are more convenient and accurate in predicting the final outcome of frostbites.

METHODS

The retrospective study of the clinical histories of 70 patients hospitalized at Chamonix Hospital (Mont-Blanc Massif) from 1985 to 1999 for severe frostbite injuries of the extremities has allowed us to classify the aspects of the initial lesions on day 0 and to compare them with final outcomes.

RESULTS

A strong correlation was found between the extent of the lesion and the outcome of each finger or toe. When the initial lesion was on the distal phalanx, the probability of bone amputation was around 1% for the digit, 31% for the middle phalanx, 67% for the proximal phalanx, 98% for the metacarpal/metatarsal, and 100% for the carpal/tarsal.

CONCLUSIONS

Based on these clinical results and on the results of bone scans (previously validated), a new classification of frostbite severity at day 0 is proposed. Four degrees of severity are defined: first degree, leading to recovery; second degree, leading to soft tissue amputation; third degree, leading to bone amputation, and fourth degree, leading to large amputation with systemic effects.

Hyperbaric oxygen treatment in deep frostbite of both hands in a boy

An 11-year-old boy in good general health conditions suffered deep frostbite on six fingers while he was working without gloves as a beater during a hunt in Poland at an outdoor temperature of -32 degrees C over a 4 h-period. Three days later he was first seen by a physician who planned to amputate the affected fingers. The patient was transferred by his family to our University Hospital in Aachen, Germany. We found third degree frostbite on four fingers of the right and on two fingers of the left hand. Because of the late beginning of the therapy, the patient was treated by HBO(2) according to the Marx-schema for problem wounds (2,4 bar, total time at depth: 90 min, alternations of 100% O(2) and air breathing). HBO(2)-treatment was repeated daily for 14 days. No adverse events were recorded during the course of therapy. A total recovery of the severe frostbite was observed after 14 days of HBO(2)-treatment. Twenty-eight months after the injury the patient reports fully regained sensibility and no pain. The plain X-ray after this period showed no premature closure of the epiphyses or sclerosis of the metaphyses.

CONCLUSIONS

Because of the low risk associated with HBO(2), and its potential therapeutic efficiency, HBO(2) should be recommended as adjunct therapy in the treatment of deep frostbite.

Free flap coverage of bilateral frostbite of the feet

The indications, principles of management, and outcomes of free flap transfer for limb salvage in four patients with bilateral frostbite of their feet are presented. A fasciocutaneous flap was used for coverage when the wound involved a single surface of the foot. When multiple surfaces of the foot required free flap coverage, a muscle flap was used because it could more easily improve the shape and contour of the defect. Successful coverage was achieved in all four patients.