Kogan L., Lebenthal A., Breiterman S., Eldad A.

Ann. Burns and Fire Disasters, 14: 85-9, 2001

We commend the Authors for the effort they have put in their work and in reporting their results. However, serious flaws in the study design proper as well as in the measured parameters shed considerable doubts on the validity of the study and on its reported outcome. The Authors describe an experimental comparative trial on the effect of the Chinese moist exposed burn ointment (MEBO) and Bacitracin ointment on healing of partial-thickness burns in 40 female guinea pigs. The guinea pigs were depilated chemically before sustaining controlled contact burns. It is common knowledge that even mild skin cleansers may produce irritation and have a profound effect on cutaneous barrier function.1-4 The cosmetic depilatory cream used (Alpha Cosmetica) by itself may have introduced unknown variables that would influence the healing mechanisms. The animals were grouped in four separate groups. Group 1 consisted of 10 animals that sustained deep partial-thickness burns on each side of the body. The right side was treated with Mebo while the left side was treated with Bacitracin; hence direct comparison of the two treatment modalities was available for each animal. Two animals of this group died on day 14. Group 2, on the other hand, was also composed of 10 animals that sustained two burns each. However, contrary to what is stated in Table I, the animals were not treated as in group 1. Instead, five animals were treated with Mebo, and the other five were treated with Bacitracin. In this group, only three Bacitracin-treated and four Mebo-treated animals survived. The same treatment modality was also applied for group 3. This inconsistency and the inadequate categorization of the various study groups in Table I may have affected the statistical analysis.

The Authors evaluated healing by planimetry and punch biopsies on days 1, 3, 7, 10, 14, and 21. Planimetry measures wound surface area that can be accurately calculated from standardized digital photographs with computerized planimetry (Image Tool 2.0). The decrease in surface area and the progression of the Healing Index:

Healing Index (HI) = (Ulcer size day 0 - Ulcer size day X)/(Ulcer size day 0)

are extremely valuable in quantifying healing of full- thickness wounds that proceed by wound contraction and re-epithelialization from the wound edges. This type of healing, on the other hand, is not significant in healing of partial-thickness wounds that heal primarily by re-epithelialization from the retained epithelial cells present throughout the wound beds. Planimetry measurements, therefore, cannot be of any value to assess healing of partial-thickness burns. This is better assessed by trans-epidermal water loss (tewl) measurement.5 Protein permeability across the wound surface measurements reflects even more reliably and objectively surface reepithelialization.

The punch biopsies performed by the Authors could be a reliable method to evaluate anatomical surface re-epithelialization. The Authors reported better healing with Mebo treatment; however, the improved healing was not statistically significant. This is probably because of the small number of animals in each group included in the comparative study but most likely owing to the fact that between the 10th and the 21st day, the period during which healing is expected and any differences are to be observed, only one punch biopsy was effected, on day 14. Moreover, the scoring modality the Authors have used to quantify healing is rather arbitrary. As an example, regarding epithelial regeneration, a score of 1 is given to 25-75% surface epithelial coverage, which is an extremely wide bracket that by itself could mask any difference between the two treatment modalities.

Our studies with Mebo (Julphar Gulf Pharmaceutical Industries, uae),5,7,8 though not from the same ointment manufacturer, Mebo (Rongxiang Pharmaceutical, China), have demonstrated improved healing of partial-thickness wounds. The conclusion reached by the Authors as it applies to their study model, as stated, cannot be justified.

Bishara S. Atiyeh, M.D.,

F.A.C.S., Associate Clinical Professor of Surgery,

Division of Plastic & Reconstructive Surgery,

American University of Beirut Medical Center, Beirut, Lebanon

John Ioannovich, M.D.,

Professor of Plastic Surgery, Director,

Department of Plastic Surgery and Burns,

General State Hospital of Athens, Athens, Greece

BIBLIOGRAPHY

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2. Fartasch M.: Ultrastructure of the epidermal barrier after irritation. Microsc. Res. Tech., 37: 193-9, 1997.
3. Wortzman M.S.: Evaluation of mild skin cleansers. Dermatol. Clin., 9: 35-44, 1991.
4. Treffel P., Gabard B.: Stratum corneum dynamic function measurements after moisturizer or irritant application. Arch. Dermatol. Res., 287: 474-9, 1995.
5. Ioannovich J., Tsati E., Tsoutsos D., Frangia K. et al.: Moist exposed burn therapy: evaluation of the epithelial repair process (an experimental model). Ann. Burns and Fire Disasters, 13: 3, 2000.
6. Breuing K., Erikson E., Liu P., Miller D.R.: Healing of partial thickness porcine skin wounds in a liquid environment. J. Surg. Research. 52: 50-8, 1992.
7. Atiyeh B.S., Ghanimeh G., Kaddoura I.L., Al Amm C., Ioannovich J.: Split-thickness skin graft donor site dressing: Preliminary results of controlled clinical comparative study of MEBO and sofra-tulle. Letter to the Editor, Ann. Plast. Surg., 2001.
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