Serial Debridement Under Scrutiny

Serial sharp debridement, also called maintenance debridement, is suggested to benefit chronic wounds by removing biofilm, which may precede some infections.¹ While debridement of necrotic tissue is part of standard care for most chronic wounds,^2,3 studies cited as supporting bedside sharp debridement or more invasive surgical debridement4 provide inadequate randomized clinical trial (RCT) support for healing benefits. Examples include:

• (a): a retrospective analysis⁵ of clinical trials on 366 venous ulcers and on 310 diabetic foot ulcers reporting a nonsignificant correlation between increasingly frequent surgical debridement and increased rates of wound closure;
• (b): a post hoc subset analysis of centers studying platelet-derived growth factor (PDGF) reporting that PDGF healing efficacy was greater in more frequently debriding centers;⁶
• (c): a convenience controlled trial⁷ reporting a transient 4-week area reduction in slough-covered venous ulcers sharply curette-debrided at baseline, compared to slough-free nondebrided venous ulcers that were not comparable to the sharply debrided ulcers at baseline. No healing difference persisted after 4 weeks; and
• (d): an RCT reported no differences in healing or patient quality of life improvements in 67 patients treated with either low frequency ultrasound or surgical debridement.⁸

None of these studies supports a conclusion that sharp or surgical debridement speeds healing compared to another method of debridement. Instead, they report associations that may arise from variables other than the method of debridement. This enticing web of opinion and coincidence may misinform consensus statements that recommend sharp debridement, ⁹ potentially distracting wound care professionals from addressing causes of tissue damage or using autolytic debridement, which has better evidence of optimizing healing.¹⁰ In search of better evidence, this Evidence Corner describes a recent RCT studying the interaction of serial sharp debridement with enzymatic debridement11 and a debridement literature review.⁴

Reference. Motley TA, Lange DL, Dickerson JE Jr, Slade HB. Clinical outcomes associated with serial sharp debridement of diabetic foot ulcers with and without clostridial collagenase ointment. Wounds. 2014;26(3):57-64.

Rationale. Debridement is an accepted component of care for diabetic foot ulcers (DFUs), with improved healing as an important expected outcome.

Objective. Conduct an exploratory randomized controlled trial (RCT) to describe effects of topical debridement with or without collagenase ointment as an adjunct to clinically indicated initial and/or serial sharp debridement of DFUs.

Methods. A prospective, 7-center open-label RCT compared effects of standard of care (SOC) off-loading and initial and/or serial sharp debridement on 12-week healing of diabetic patients with neuropathic, uninfected, nonischemic foot ulcers measuring 5 cm²-10 cm² in area that required debridement. Patients included had serum prealbumin > 15 mg/ml and HbA1c < 12%, with a DFU of at least 1 month duration. Patients were excluded if they required no debridement, had uncontrolled diabetes, or had a bleeding disorder, systemic infection, or osteomyelitis of the target foot. All DFUs were partial-thickness, not extending below the dermis. One to 5 days after the initial blood sample to determine eligibility, all target DFUs were sharply debrided. Then, after measuring the baseline area of the wounds, the DFUs were randomized by computer to receive 6 weeks of SOC including serial sharp debridement either with or without enzymatic debridement,with clostridial collagenase ointment (CCO) applied 2 mm thick once daily. The control group with no CCO received daily wound care and dressings at the investigator’s discretion, excluding hyperbaric oxygen or negative pressure therapy. During 6 weeks of follow-up, all open target DFUs received a primary foam dressing with optional hydrogel, covered with 1 layer of cast padding held in place with a self-adherent elastic bandage until DFU closure or week 12, whichever came first. Serial sharp debridement was performed, followed by digital wound area measurement during weekly clinic visits if a combined score of 3 or more was reported on standardized scales of edge, undermining, necrotic tissue type, or amount adapted from the Bates-Jensen Wound Assessment Tool. Between clinic visits, patients were instructed on wound cleansing with sterile saline and application of their assigned topical wound care. Safety was assessed as frequency of adverse events. Percent of wounds healed and percent wound area reduction from baseline were assessed at 6 and 12 weeks after the first treatment and analyzed using a paired t test for significance of healing comparisons or analysis of covariance for risk-adjusted outcomes analysis. Chi square tests compared baseline and demographic values for the 2 groups. Missing values were imputed as group means or “0” area if healed. Sample size was set at 48 per group, with each center contributing at least 2 subjects to each treatment group to support a descriptive study, not a study to test the hypothesis of healing effects of either intervention.

Results. Six weeks of adding CCO to serial sharp debridement (n = 28) reduced wound area from baseline at both 6 weeks and 12 weeks after the first treatment (P < 0.001), but serial sharp debridement (n = 27) did not significantly reduce wound area at either time point. Though wound bed and appearance improved over the course of the study in both groups (P < 0.044), there were no significant differences between groups in percentage change in wound area from baseline to either time point, any subscale of wound appearance, time to wound closure, or adverse events.

Authors’ Conclusions. Though limited by its unblinded design, this study reported 68% DFU area reduction in 6 weeks, replicating the 11% per week area reduction reported in a prior 4-week study using CCO alone without sharp debridement. More research is needed to contrast and clarify effects of different debridement interventions.

Reference. Strohal R, Apelqvist J, Dissemond J, et al. EWMA document: debridement. J Wound Care. 2013;22(suppl 1):S1-S52.

Rationale. Despite the central role of debridement in wound care, there is no evidence-based algorithm for why and when to debride which types of wound with which interventions.

Objective. This literature review aimed to define debridement options with benefits and limitations of each and provide an algorithm for clinical use of each debriding intervention

Methods. Defining debridement as “the act of removing necrotic material, eschar, devitalised tissue, serocrusts, infected tissue, hyperkeratosis, slough, pus, hematomas, foreign bodies, debris, bone fragments or any other type of bioburden from a wound with the objective to promote wound healing,” the authors summarized best available evidence supporting clinical healing and economic outcomes of indications and methods of use for each form of debridement: mechanical with gauze, autolytic, enzymatic, absorptive or honey dressings, larval, jet lavage systems, ultrasound, negative pressure, low frequency ultrasound, surgical, and sharp debridement options. An evidence-based algorithm summarizes best available debridement options for major wound categories.

Results. Parameters influencing the decision to debride a wound include pain, patient biological age and comorbidities, environment, choice and consent, quality of life, skill and resources of the caregiver, regulations, and guidelines. Evidence on cost and resource utilization is summarized for each intervention and tabulated for each debridement intervention. Sharp debridement is described as fast, more cost-efficient and resource-efficient than the more invasive surgical debridement, but with a high risk of infection if sterile conditions are not ensured. The only studies described as supporting sharp debridement are those already noted as (a) through (d),^5-8 which fail to report a healing or other relevant benefit of sharp debridement compared to any other form of debridement on comparable wounds at baseline.

Authors’ Conclusions. The authors concluded that, in spite of the current major role of surgical debridement in wound management, there is a paucity of available evidence to document the benefits. Surgical and sharp debridement are rapid methods of removing devitalized or necrotic tissue, but should be used with caution, avoiding risk of overexcision and wound damage which may delay later healing.

A literature review on debridement⁴ found no significant healing or patient-oriented outcome benefit of sharp serial debridement compared to any other debridement intervention. The study exploring serial sharp debridement with vs without CCO¹¹ reported improved healing only if CCO was added to serial sharp debridement within the context of good SOC for DFU. By design, the study did not compare the 2 debriding interventions, so serial sharp debridement remains without RCT evidence of efficacy compared to other debriding interventions. It raises the question whether healing benefits of CCO may match or exceed those of serial sharp debridement. To date, autolytic debridement with a hydrogel remains the only debridement intervention with consistent evidence of healing benefits on DFUs compared to mechanical debridement with gauze.¹⁰ Patients deserve care that works. This requires RCTs to compare healing outcomes of evidence-based autolytic debridement using hydrocolloid dressings, hydrogels, or honey, to sharp serial debridement or other debriding interventions. The persistent lack of compelling evidence to support serial sharp debridement raises the question of whether there may be more effective courses of action to manage necrotic tissue or to minimize biofilms. For example, increasing evidence suggests that strands of gauze in contact with wounded tissue potentiate infection.^12,13 Might they be acting as foreign matter substrates for biofilm formation?

This may be yet another reason to avoid gauze wound dressings. Only science can tell us for sure.

Laura Bolton, PhD
Adjunct Associate Professor
Department of Surgery, Rutgers Robert Wood
Johnson Medical School, New Brunswick, NJ

This article was not subject to the WOUNDS peer-review process.