Considerations on the development of surgical techniques for the treatment of onychocryptosis

. Rashmi TM, Sathish HS. Earliest details of dermatology by Ayurveda. An Bras Dermatol. 2021;96:649--50. . Ferreira IG, Weber MB, Bonamigo RR. History of dermatology: the study of skin diseases over the centuries. An Bras Dermatol. 2021;96:332--45. . Mirzaei MR, Ghazi-Sha’rbaf J, Mohammadinasab R. Letter to the Editor regarding: ‘‘History of dermatology: the study of skin diseases over the centuries’’. An Bras Dermatol. 2021;96:648--9. a Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil b Santa Casa de Misericórdia de Porto Alegre, Porto Alegre, RS, Brazil c Faculty of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil


Dear Editor,
As onychocryptosis is a frequent demand in dermatological assistance, and its surgical management requires both specific training and indication criteria, we read with interest the article by Ma, 1 which aimed to describe a new surgical approach for onychocryptosis.
Currently, there is no consensus, nor a body of evidence on the specific differences of the several surgical techniques for onychocryptosis, or on their comparison in terms of effectiveness, morbidity, infection, cost-effectiveness and technical difficulty. Therefore, the development of new methods is of scientific relevance and should be critically appreciated considering the described surgeries, especially regarding the technical differences and recurrence rates after 12 months.
Despite the interesting results presented by Dr. Ma, the proposed surgical technique sequence is very similar to the classic matricectomy described by Winograd (1929), 2 which has undergone several adaptations over the years. 3 in virtually all studies that used the Winograd method or its variants. 4 As this is a similar surgical approach, the result shown by Ma, who found no recurrence in 67 surgeries (with a follow-up of 6 to 12 months), may not represent a difference in relation to the expected rate of 6% (p = 0.119 ---Fisher Exact test) due to modest sample size. However, it can also be due to the small percentage of cases with grade I onychocryptosis, which usually do not show recurrence and whose frequency was not discriminated by the author. Table 1 depicts the main technical characteristics of the Winograd method and its main variants, its recurrence rates, in addition to chemical matricectomy with 88% phenol and 80% trichloroacetic acid, for comparison. 5 Surgical techniques for the treatment of onychocryptosis require careful systematization of the operative sequences and approach to the matrix, as well as the precise indication according to tissue hyperplasia, nail plate situation and pyogenic granuloma. Only the comparative analysis of the performance of the techniques, stratified according to the indications, can lead to criticism, aiming to maximize the performance of the procedures.
Due to the peculiar anatomy of the nail apparatus, surgical approaches to onychosis require specialized training by the dermatologist. However, despite the high prevalence of onychocryptosis and impact on quality of life, there is a lack of well-conducted comparative clinical trials that favor the personalization of indications. Moreover, it is crucial to review the previously described surgical techniques, both for their historical and scientific value, when one proposes the standardization of a new surgical technique.

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Conflicts of interest
None declared. The key point to narrow the nail plate is to destroy the corresponding part of the nail matrix completely. Treatments include surgery, electrocautery, and chemicals, etc. The most assured is the surgical excision. There are clear points and lines of reference in every step of the surgical approach I proposed. In the discussion, I emphasized that Step 4 is the most important procedure to avoid recurrence. I was very careful to cut off all the tissue around the corresponding part of the nail matrix in all my 67 patients. And there are still two suggestions: 1) to see the white phalanx; 2) to perform a little wedge-shaped resection. As a result, I am very confident to guarantee low recurrence or even no recurrence after surgery.
I have propagated my technique in more than fifteen hospitals in southern China. Most dermatologists only need to observe and listen once to achieve results similar to mine. Even so, with the established method, there may be a few differences in the final recurrence rate among different doctors.