Larva Terapia.com.ecDr. C.A. Vincent M.D.INTERNISTAManuel Galecio 1208 y Av. del Ejército (Centro Guayaquil)Bálsamos #629 e/ Ficus y Las Monjas (Urdesa)Telf.: 2280008 / 2320936 Cel.: 0981137366 / 097226405Guayas - Ecuador
was loosely covered with gauze, which was changed every 4–6 hours. Between MTcycles, wounds were dressed with gauze moistened with saline or 0.125% sodiumhypochlorite. All wounds were evaluated visually, photographed, measured, and tracedevery 2 weeks. Wound healing rate was calculated by dividing wound area by woundcircumference. Paired t-tests compared pre-MT versus MT healing rates.Results: Forty-three evaluable patients received MT by convenience assignment at sometime during the study and 49 received CT. On enrollment, the MT patients had largerPUs with higher likelihood of diabetes or spinal cord injury and higher average serumalbumin than the CT patients. Necrotic tissue and wound size decreased faster andgranulation tissue improved more during the first 4 weeks of treatment in the MTcompared to CT patients (P < 0.05), though healing time and the percentage of woundshealed after 12 weeks were not significantly different between the 2 groups. The onlyvariable significantly associated with PU debridement was MT. Thirty-one PUs treatedfirst for an average of 4.8 weeks with CT and then treated with MT for an average of 5.2weeks increased in size during CT, then decreased in size during MT (P < 0.001).Conclusion: These results establish the foundation for prospective clinical trialscomparing MT to other debridement modalities on PUs.Maggot Debridement of Ulcers in Patients with DiabetesReference: Sherman RA. Maggot therapy for treating diabetic foot ulcers unresponsiveto conventional therapy. Diabetes Care. 2003;26(2):446–451.Rationale: Maggot therapy selectively debrides necrotic tissue. However, the optimalrole has not been clarified in the management of chronic wounds.Objective: The objective of the study was to determine the effectiveness of MT inmanaging foot and leg ulcers (DUs) failing conventional treatment in hospital patientswith diabetes.Methods: A retrospective analysis of the aforementioned database was conducted on143 patients with diabetes with 260 nonhealing DUs referred to the MT service in a USVeterans Administration hospital. Twenty wounds on 18 patients qualified for analysis.Six DUs were treated with conventional surgical or nonsurgical therapy (CT), 6 withMT, and 8 with CT for at least 2 weeks followed by MT. Ulcers were neuropathic inorigin for 86% of the 14 subjects receiving CT or CT+MT and 64% of the 14 subjectsreceiving MT or CT+MT. Wound dimensions, area, healing rate at 4 and 8 weeks,necrotic tissue, granulation tissue, and time to complete healing were measured.Results: The analysis combined the 6 subjects receiving CT or MT only with the 8subjects receiving CT first followed by MT, rendering it impossible to compare effectsof CT only with MT only. At first glance, paired t-test results for the 8 subjectsreceiving CT (for “~ 5.6 weeks”) to MT (“completely debrided in 4 weeks”) appearmore compelling, reporting statistically significant effects on necrotic tissue and woundarea. However, the most common CT debridement modality was wet-to-dry gauze,currently recognized as substandard care. Only 1 CT patient received hydrogel, adebriding modality with evidence supporting healing efficacy in diabetic foot ulcers.Percent of DU closed during 4 weeks did not reach statistical significance (0% for CTcompared to 14% for MT).
Conclusions: While the results are interpreted as supporting efficacy of MT ascompared to CT on DUs, many questions remain unanswered, and a large prospectivetrial is warranted.Clinical PerspectiveThe Cochrane conclusion agrees with the conclusions of these MT articles. While theevidence is insufficient to support a firm conclusion of efficacy of larval therapy in anychronic or acute wound, appropriately powered prospective, randomized, controlledtrials (RCTs) are warranted. When these RCTs are conducted, it is hoped that MT willbe compared to a hydrogel under a moisture-retentive dressing, a modality withsignificant evidence of debriding efficacy during 14 days of use.Valuable lessons can be learned from this literature. First, there is an inherent flaw inproceeding from CT to MT and assuming that wound size reduction reflects debridingefficacy. Necrotic tissue debridement is often initially associated with perceived woundenlargement before healing proceeds to close the wound. Successive treatments shouldalways be conducted in completely balanced cross-over studies to control for this effect.Second is the issue of whether to measure healing, debridement, or both. Technically,debridement efficacy is efficacy in removing necrotic tissue. Subsequent healing variesaccording to the wound environment or extent to which the cause of tissue damage hasbeen consistently and completely alleviated. The MT literature and some hydrogelliterature have measured both debridement and healing. For example, the onlyprospective MT RCT found in the literature6 compared MT (n = 6) to a hydrogel with agauze (HG) secondary dressing (n = 6). In this MT RCT, only 2 HG patients ascompared to all 6 MT patients were debrided in 1 month. This result does not matchprior published hydrogel debridement results, possibly owing to differences inapplication techniques or debridement measures. In a prospective RCT using validateddebridement measures, Romanelli reported significant debriding efficacy of ahydrogel (n = 16) compared to an enzymatic agent (n = 16) during the first 14 days oftherapy when both were covered with an occlusive film dressing. This literaturesuggests that 1) validated measures of debridement are appropriate for comparingefficacy of debriding agents and 2) gauze is no longer an accepted standard dressing indebridement studies. It may be associated with substandard debriding outcomes,masking efficacy when used in conjunction with an evidence-based debriding modality,such as a hydrogel. There is sufficient evidence to use standard validated debridementmeasures5 and to avoid gauze, defining a hydrogel covered with a moisture-retentivedressing as a best practice standard debriding dressing for future research.References1. Parish LC, Bolton LL. Evidence-based dermatology and wound healing: let’s getreal! Skinmed. 2006;5(1):6–7.2. Saap L, Falanga V. Debridement performance index and its correlation withcomplete closure of diabetic foot ulcers. Wound Repair Regen. 2002;10(6):354–359.3. Smith J. Debridement of diabetic foot ulcers. Cochrane Database Syst Rev.2002;(4):CD003556.4. Williams D, Enoch S, Miller D, Harris K, Price P, Harding KG. Effect of sharpdebridement using curette on recalcitrant nonhealing venous leg ulcers: a concurrentlycontrolled, prospective cohort study. Wound Repair Regen. 2005;13(2):131–137.5. Romanelli M. Objective measurement of venous ulcer debridement andgranulation with a skin color reflectance analyzer. WOUNDS. 1997;9(4):122–126.6. Wayman J, Nirojogi V, Walker A, Sowinski A, Walker MA. The costeffectiveness of larval therapy in venous ulcers. J Tissue Viability. 2000;10(3):91–94.
7. National Institute for Clinical Excellence. Guidance on the use of debridingagents and specialist wound care clinics for difficult to heal surgical wounds.Technology Appraisal Guidance—No. 24. London, UK: National Institute for ClinicalExcellence; April 2001.Laura L. Bolton, PhD, FAPWCA, Adj. Assoc. Prof., UMDNJ; WOUNDS EditorialAdvisory Board Member and Department Editor________________________________________