Onychocryptosis is a disease of the nail plate in which an abnormal interaction with the nail fold produces ingrowth, causing pain, inflammation, and even recurrent infection.1 With time, a highly vascular and very tender granulation tissue develops, producing marked morbidity, with difficulty walking and even time off work.2,3

Onychocryptosis is a common health problem, accounting for 20 of every 100000 first consultations and 20% of foot problems.1,4–6 It can present at any age, though it is most common between 15 and 40 years, with a male predominance of 3 to 1.4

Based on clinical experience, the great toe is most commonly affected, usually unilaterally, although the condition can be bilateral.1

Onychocryptosis is classified into 4 stages according to the severity and duration of the disease.3,7 In stage 1, the lateral nail fold is tender and presents erythema and mild edema. The nail fold has not grown over the border of the nail plate. Stage 2 is divided into 2 substages: stage 2A, in which symptoms deteriorate and a serous secretion and infection may develop (the nail fold overlaps the surface of the nail but by less than 3mm); and stage 2B, with symptoms similar to those of stage 2A, but the hypertrophic fold overlaps the nail plate by more than 3mm). In stage 3, symptoms become more intense and chronic granulation tissue and hypertrophy of the nail fold develop. The granuloma or hypertrophic tissue covers a large part of the nail surface. Inadequate treatment can lead to further progression, with severe chronic deformity. Finally, stage 4, the result of progression from stage 3, presents greater deformity of the nail plate and folds; stage 4 is differentiated from stage 3 by hypertrophy of the distal nail fold.

Mild, stage 1 disease can be treated medically, while moderate and severe forms (stages 2, 3, and 4) require surgery.8

Two surgical strategies are used: reduction of the nail plate and reduction of the soft tissues of the great toe. The aim in both cases is to optimize the relationship between the nail and the soft tissue. Treatments that aim to reduce nail size include chemical cautery or partial matricectomy with 88% phenol; this is usually the most widely used technique,9 and it consists of partial surgical ablation of the nail plate using a 80% to 95% solution of phenol in distilled water. The solution, applied under local anesthesia, has 3 main actions: necrosis, disinfection, and anesthesia.9,10

Treatments that reduce the soft tissues, such as the Howard-Dubois and VandenBos procedures, are designed to reduce or eliminate excess tissue.9 The super U technique was first described by Dr. Ival Peres Rosa in 1989.11–13 It is used in cases of severe nail-fold hypertrophy and achieves good healing and a good cosmetic result, with low recurrence rates and no risk of infection.13,14

In this article, we report our experience in patients with onychocryptosis treated surgically using the super U technique.

Between January 2014 and January 2015, 10 patients (5 men and 5 women) aged between 15 and 61 years (mean age, 35.7 years) underwent surgery for onychocryptosis in the dermatology department using the super U technique (Table 1)

Only 1 patient had bilateral disease (Fig. 3). The severity of onychocryptosis, based on the staging classification, was stage 1 in 1 patient, stage 2 in 6, and stage 3 in 3. No patients presented stage 4 disease.

Figure 3.

Patient 3. Bilateral stage 3 disease. A, Right great toe. B, Left great toe: A dermographic marker is used to outline the tissue to be excised. C, Intraoperative image after U excision of the periungual granulation tissue. D, Four weeks after surgery, silver nitrate is still visible on the nail plate.

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The mean time between onset of the disease and treatment using the super U technique was 87 months (range, 4–444 months).

Half of patients had undergone previous surgery of their onychocryptosis using other surgical techniques.

A total of 6 follow-up visits were performed; 2 patients only attended 3 of these visits. Mean time to healing was 6 weeks.

Complications were only observed in 1 patient, who developed postoperative infection requiring treatment with systemic antibiotics. Pain was evaluated at the follow-up visits using a VAS. Seven of the 10 patients reported pain during the week after surgery, with a mean VAS score of 5 in 6 of them. Only 1 patient reported maximum pain for more than a week, related, in this case, to preoperative bone changes and not to the surgical technique.

Nine of the 10 patients were satisfied with the cosmetic appearance evaluated at the follow-up visit at 1 year.

Two patients presented recurrence prior to the 1-year follow-up visit.

Various treatments are available for onychocryptosis, from conservative management to complex surgical procedures that require considerable experience.10 Surgery must be considered in cases with pain, recurrent onychocryptosis, surgical recurrence, onychogryposis, chronic recurrent paronychia, or failure of conservative management.7 Management should be conservative in patients with stage 1 disease.3,8 The super U technique can be used in patients with disease in stage 1 or 2 that recurs after treatment, though recognizing that this is an aggressive procedure compared with other existing techniques. The patient with stage 1 disease in our series presented recurrence and severe pain after previous surgery.

According to the literature, partial matricectomy with phenol is more often used in stages 1 and 2A.4 Phenol matricectomy is a rapid, simple, and inexpensive technique. Inflammation and wound healing persist for at least 2 to 3 weeks, with full recovery a month after treatment.10

Recurrence occurs in up to 24%,3,10 probably caused by incomplete matricectomy, with new nail growth in the lateral fold.9 The main disadvantage is that the nail is narrower, typically producing a poor cosmetic result.15

The Howard-Dubois procedure consists of a fish-mouth incision running below and parallel to the lateral and distal nail folds, accompanied by a second incision to create a wedge in the center of the distal wall, with subsequent excision of the crescent of tissue. This technique is considered best for mild to moderate cases, while the super U technique is the best option for severe disease in stage 3 or 4.9 The results are good with both techniques, but the Howard-Dubois operation can lead to necrosis of the wound margins if excessive tissue is removed in cases with moderately hypertrophic lateral folds; this does not occur with the super U technique. In addition, the Howard-Dubois procedure is very painful, requiring good analgesic control.9 Another technique similar to the super U procedure is the one described by Vandenbos. The differences between the 2 procedures are that the proximal part of the incision in the super U technique does not include the proximal nail fold, the distal fold is excised, and hemostasis is achieved using a running lock suture.9,13,14

In our series of 10 patients undergoing the super U procedure, the majority stated they were satisfied with the operation, and recurrence and complication rates were low. We therefore consider that this technique achieved excellent resolution of the disease in almost all our patients.

It is important to draw attention to the patients in who previous treatments had been unsuccessful using techniques distinct from the super U procedure. Of these patients, 4 showed an excellent response to the new procedure, with mild to moderate pain of short duration, an absence of infection, and satisfaction with the cosmetic result. In patients with a long history of the disease or who have undergone previous surgical treatments, the super U procedure therefore appears to be an effective option.

With respect to patients with more advanced disease (stage 3), super U excision is seen as a good option, as the clinical course in all our patients was excellent, with no recurrences or complications.

Another relevant point is postoperative follow-up, especially to control granulation tissue formation and to prevent its hypertrophy by using topical silver nitrate. The super U technique requires very strict nursing control, which is usually complete within 30 to 45 days.

Comparing the results in our patients using the super U technique described by Dr. Peres Rosa, with the results described in the literature for partial matricectomy with phenol,3,5,6,10 we can conclude that both techniques have been shown to be safe, simple, and effective. Both procedures have a low recurrence rate and a relatively similar postoperative recovery, though time to healing is shorter with partial matricectomy with 88% phenol. However, the super U technique preserves the whole nail, adapting the soft tissues of the great toe to the nail, leading to a much better cosmetic result than with matricectomy.

Our study is limited by the small number of patients. No studies designed to compare the super U technique with any other type of surgery have yet been published.

It is very difficult to select a treatment for onychocryptosis that satisfies all patient characteristics and requirements, and more so when resolution of the disease varies with its duration.

Based on our experience and the results of the study presented, we consider that the super U procedure is a very useful technique. It is the best option for severe onychocryptosis that presents hypertrophy of the lateral and distal nail folds, and for stage 2 disease in which previous treatments have failed.

The authors declare that they have no conflicts of interest.