Perioperative management - Karydakis flap procedure for pilonidal sinus

• Asymptomatic pilonidal sinus of many years (if desired by patient)
• Chronic pilonidal sinus
• Acute pilonidal sinus with abscess (staged procedure: 7-10 days post abscess evacuation/stab incision under LA/cryoanesthesia

• Asymptomatic pilonidal sinus without signs of inflammation does not require treatment. Inform the patient about possible chronic infections and acute abscess formation, and that years later malignant transformation (extremely rare; mostly squamous-cell carcinoma) may occur. For this reason, the local findings must be followed up by annual clinical examinations in order to initiate further histological work-up in the event of an abnormal finding.
• Radical excision in case of abscess is unreliable and carries with it a high recurrence rate (up to 41%). Therefore, the first step should be to unroof the abscess to ensure effective drainage. This is followed by radical excision during the infect-free stage 5-7 days later.

If pilonidal sinus is suspected, first note risk factors such as excessive body hair, copious sweating, obesity, and poor personal hygiene. Differential diagnosis then must first establish whether there is:

• A porus without inflammation
• Sinus with acute abscess formation
• Sinus with chronic secretion

Usually, ultrasound, CT or MRI are not required.

• In porus without inflammation, inform the patient about the course of the disease, emphasizing the fact that spontaneous healing is not possible and malignant transformation may be possible in very rare cases. Schedule the patient for annual follow-ups.
• In case of acute abscess, the typical signs of a soft tissue abscess with local redness, warmth and swelling paramedian to the gluteal fold are usually present. Pilonidal sinus with acute abscess requires immediate treatment, and the first step should be surgical abscess drainage (1-2 cm long incision under local anesthesia). In addition to verifying the tetanus status, a calculated oral antibiotic regimen (e.g. with moxifloxacin) should be initiated. Monitor the wound daily until the operation and perform definitive surgery after five to seven days.
• In chronic pilonidal sinus, explore the tract with a bulb-headed probe and lavage with saline. Until the operation ensure that the opening of the fistula is not obstructed, which otherwise would promote subsequent abscess formation.

• Presentation of the various surgical techniques: Karydakis flap procedure, rhomboid excision with Limberg rotation flap, radical excision of the sinus with subsequent secondary wound healing.
• Recurrence The recurrence rate of all techniques is reported as about 4%.
• Suture line dehiscence and abscess formation
• Bleeding
• Unsightly cosmesis in the gluteal region
• Impaired skin sensitivity