Pilonidal disease is morbid condition of young productive population, that could impair quality of life with high cost for health care system. No consensus exists on optimal surgical treatment, even if several techniques have been proposed. In this preliminary experimental case-control study the investigators compared excision by knife and diathermy with the aim to investigate if wound dehiscence could be related to heat spreading during excision of the sinus.

Between January 2017 and February 2018, 29 patients underwent to sinus excision. The investigators considered 16 sinus excision performed by diathermy as a case group (named "Hot" group) and the last 13 procedures performed by knife as control group (named "Cold" group). Temperature data were recorded for both group. Follow-up was carried out until complete healing. Were considered primary and secondary outcomes.

Inclusion Criteria:

• male and female patients between 14 and 65 years old,
• primary, non recurrent pilonidal disease
• midline and intergluteal location
• spinal anesthesia
• dimension no more than 5 cm in length, primary closure performed

Exclusion Criteria:

• age < 14 and > 65 years old,
• secondary fistulous tracts or lateral developing/cutaneous opening
• dimension over 5 cm in length,
• local anesthesia employ
• smoker and obese patients (BMI> 25 kg/m2)
• diabetic and coagulopathies affected one
• flogged or acute or infected or abscessed forms
• ASA score > IV,
• normal range WBC and Hb preoperative values.

All patients were enrolled by outpatient surgical control for signs and symptoms of chronic sinus referred to us by a family doctor; median age was 19.2 ± 4.3 years, ranging from 14 to 52 years old; 6 patients were females and 23 males and them were request to give informed consensus to underwent to pilonidal sinus excision; 16 patients of whom 12 males and 4 females, were treated by electrosurgery as case group ("hot"), while in the control group ("cold"), 13 patients 11 were male and 2 were females.