LAUSR

DEAR EDITOR, Pilonidal sinus (PNS) is an acquired phenomenon, with more than three factors involved in its onset (hormonal factors, presence of hair, friction, sitting for long periods or infection). It occurs in the cleavage between the buttocks (natal cleft) and can cause discomfort, embarrassment and absence from work for thousands of young people. Males are affected more frequently than females. Surgical treatment is considered the best option, with a high relapse rate (5–20%). Other methods such as alexandrite laser (755 nm), diode laser (800 or 810 nm), intense pulsed light (IPL) or neodymium-doped yttrium aluminium garnet (Nd:YAG) laser have been used for epilation as an adjuvant treatment after surgical intervention. We propose a new treatment of primary PNS itself with Nd:YAG laser. We treated six patients with a clinical diagnosis of PNS using a Nd:YAG laser 1064-nm wavelength (Laserscope Lyra XP; Laserscope Inc., San Jose, CA, U.S.A.). Most of the patients were young males with a chronic disease (mean 8 8 months of time of evolution) (Table S1; see Supporting Information). All of the lesions were localized in the natal cleft and were 1– 2 cm diameter on the surface; however, the depth could vary between patients or with inflammation present in the lesion. After informed consent was obtained from the patients or their parents, all patients underwent Nd:YAG laser treatment. Before laser treatment, the area was shaved with a razor then anaesthetized with mepivacaine. The initial irradiation energy was tailored to the individual lesion based on inflammation and depth of the lesion, which was previously examined with forceps. The energy applied was 90–130 J cm , with three pulses repeated in the same area. The spot size was 5 mm in all patients and a pulse of 45–65 ms was used (Table S1; see Supporting Information). During treatment and for 1 min after, the treatment area was cooled with a Cynosure SmartCool Cryo chiller (Cynosure, Westford, MA, U.S.A.). When the laser treatment was finished, persistent hairs were removed through the sinus opening with Adson tweezers. All patients needed more than one session, so laser treatment was performed 6–8 weeks later. The end point of the treatment was when the PNS was asymptomatic and there were no signs of inflammation or suppuration and the cyst was healed (Fig. 1). The follow-up period after laser therapy ranged from 7 to 100 months (mean 52 months). All six patients responded to the curative treatment. All the patients’ sinuses were healed with three or four sessions and no symptoms recurred following treatment. No patients had severe scars or changes in skin colour or any complication related to the treatment. The surgical treatment, which is considered gold standard, has many recurrences, and down time after surgery is in some cases very prolonged. All patients in this study returned to their daily routine the day after treatment. Two studies with laser and IPL have examined the possibility of a curative treatment, but it was a light with low wavelength and poor penetration into the skin, so the epilation