SLR - April 2018 - Jennifer A. Skolnik

Toe Pressures Are Superior to Duplex Parameters in Predicting Wound Healing Following Toe and Foot Amputations

Reference: Stone P, Glomski A, Thompson S, Adams E. Toe Pressures Are Superior to Duplex Parameters in Predicting Wound Healing Following Toe and Foot Amputations. Ann Vas Surg. 2018 Jan; 46, 147–154.  

Scientific Literature Review

Reviewed By: Jennifer A. Skolnik, DPM
Residency Program: Temple University Hospital, Philadelphia, PA

Podiatric Relevance: Treatment of foot ulcerations, frequently secondary to diabetes or peripheral arterial disease, is commonplace for today’s foot and ankle surgeons. These wounds frequently result in subsequent amputation; however, prior to performing amputation, assessment of distal perfusion is necessary. Assessment of distal blood flow may initially be completed using noninvasive vascular studies, including, but not limited to, ankle brachial indices (ABI), toe brachial indices (TBI), toe pressures and waveforms. However, currently there are no accepted standard noninvasive testing parameters that accurately predict healing capability for minor lower-extremity amputations. Therefore, the authors of the present study sought to determine any diagnostic parameters or clinical factors that contributed to wound healing, thus decreasing the likelihood for further revision surgery or subsequent proximal amputation.

Methods: A retrospective review was performed of patients who underwent elective amputations up to the level of midfoot amputation at one medical center over a five-year period. To be eligible for inclusion in the study, prior to amputation, patients must have had have at least one of the following vascular studies performed: toe pressures, ABI, TBI, posterior or anterior duplex velocities or waveforms, as well as follow-up for at least 90 days postoperatively. These studies and other patient characteristics were compared between patients with healed amputations and those who did not, defined as requiring reamputation within 90 days and analyzed to determine any significant relationships or confounding variables.

Results: Of all 333 amputations included in the present study, 62 or 19 percent failed to heal and required subsequent amputation within 90 days, 39 of those going on to major amputation. Toe pressures greater than 47 mmHg were found to have a statistically greater rate of healing (87 percent) compared with those less than 47 mmHg (73 percent). Triphasic and biphasic waveforms at the level of the posterior and anterior tibial arteries were also associated with greater rates of healing. There were no statistically significant differences in the healed versus nonhealed groups when comparing ABI and TBI. Patients who failed to heal were more likely to be older. Patients with chronic kidney disease were also more likely to go on to nonhealing. Additionally, patients who had a procedure for revascularization were found to have a significantly greater nonhealing rate compared to those who had not. When investigated in the presence of the above confounders, only toe pressures greater than or equal to 47 mmHg predicted wound healing.

Conclusions: In the presence of confounders, toe pressures were the only noninvasive measure to predict wound healing prior to foot amputation. Therefore, these authors conclude that toe pressures should be regularly acquired prior to any minor lower-extremity amputation to ascertain healing potential. Specifically, pressures greater than 47 mmHg were found to be correlated with healing in the present study. This article accentuates the ability of a simple, noninvasive test to help surgeons determine potential for healing prior to amputation and to help guide the level of amputation and need for revascularization prior to amputation.  

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