SLR - May 2014 - Corey M. Fidler

Split-Thickness Skin Grafting the High Risk Diabetic Foot

Reference: Rose JF, Giovinco N, Mills JL, Najafi B, Pappalardo J, Armstrong DG. Split-thickness skin grafting the high risk diabetic foot. Journal of Vascular Surgery. 2014 Feb 8.

Scientific Literature Review

Reviewed By: Corey M. Fidler, DPM
Residency Program: Medstar Washington Hospital Center
 
Podiatric Relevance: Healing a diabetic foot ulcer is a challenging task that all foot and ankle surgeons face. Traditionally, healing these ulcers is based around techniques focused on healing by secondary intention including local wound care and tissue engineered skin grafts, which do not require harvesting or the added risk of anesthesia and postoperative hospitalization. However, the take rate of such grafts is lower than split thickness skin grafts (STSG) and could increase the time to healing, thus adding to the risk of possible future infections. The purpose of this article was to determine if STSG placement in chronic lower extremity wounds was a viable option for diabetic patients.   

Methods: This was a retrospective review of 94 patients in the inpatient and outpatient service of an integrated surgical limb salvage service who presented with chronic lower extremity wounds and underwent STSG placement. Those patients with antecedent trauma associated with their wounds or those who underwent fasciotomies were excluded from the study. Factors examined in the study group included: patient age, sex, presence of diabetes, presence of dialysis dependent renal failure, indication for STSG, wound location (plantar vs. nonplantar), graft size, time to healing, and ambulatory status.

Surgical technique was performed in a consistent fashion, with pre-operative preparation of the wound bed to healthy granulation tissue via a surgical blade or Versajet. Next the graft was harvested with an electric dermatome from the ipsilateral thigh at a thickness of 0.012-0.018 inches thick and secured into place with 4-0 chromic gut sutures. Negative pressure wound therapy was utilized for three days at the recipient site. A location specific offloading protocol was used for plantar wounds consisting of four weeks in a removable cast walker followed by TCC as tolerated. Nonplantar wounds received edema-control and trauma protection dressings.

Data were grouped by presence of diabetes and plantar or nonplantar wound location. A univariate analysis of covariance was used to compare the wound healing times between groups. Patient age and sex were considered covariates with results being weighted according to the initial wound size. Between group differences for time to wound healing was compared and the differences in wound survival probability was estimated.

Results: There were 94 patients (72 percent male) in the study group, with a mean age of 61.0 ± 12.8 years.  66 (70.2 percent) of these patients had diabetes, including 13 who were dialysis-dependent, with the remaining 28 patients presenting with chronic wounds nondiabetic in origin. The average duration of follow-up was 12.0 ± 12.9 months. After STSG placement, 65 (69.1 percent) experienced complete graft incorporation and healing, and 18 (19.1 percent) required revision, 5 (5.3 percent) of whom ultimately required major limb amputation. There were no differences in healing when wounds in patients with and without diabetes or plantar vs. nonplantar wound locations were compared (P>.05). Similar results were observed after adjusting the results for initial wound size. Although dialysis patients had a threefold higher rate of STSG revision (46.2 percent vs. 14.8 percent; p = .01), the cumulative rate of wound healing as a function of time was independent of end-stage renal disease (p = .83).

Conclusions: The results of this study suggest that STSG can be an effective method for management of wound healing irrespective of wound location and the presence of diabetes, in particular with the augmentation of postoperative NPWT. A meta-analysis of the few publications regarding this topic by McCartan and Dinh computed a graft take of >90 percent in 78 percent of patients by eight weeks. Unfortunately, many diabetic patients are plagued by a spectrum of diseases including CAD, PVD, and chronic kidney disease, all of which increase the risk of delayed wound healing. Therefore, when selecting a closure method for diabetic foot wounds it is imperative that all comorbidites be considered, as it is likely that patients with a higher comorbidities index will result in graft failure. 

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