Perioperative management - Operation according to Karydakis

• long-standing asymptomatic pilonidal sinus (upon patient request)
• chronic pilonidal sinus
• acutely abscessing pilonidal sinus (two-stage: 7-10 days after abscess clearance/incision in local anesthesia/cryotherapy)

• An asymptomatic, non-irritated pilonidal sinus requires no further therapy. The patient should be informed that chronic or acutely abscessing infections may occur, and that in extremely rare cases, malignant degeneration (usually a squamous cell carcinoma) is possible after years. For this reason, annual clinical examinations of the local findings should be conducted to initiate further histological examination if the findings are suspicious.
• Radical excision in the abscess stage is uncertain and is associated with a high recurrence rate (up to 41%). Therefore, initially only unroofing of the abscess for effective drainage. Radical excision is performed in the infection-free stage after 5-7 days.

In the case of suspected pilonidal sinus, risk factors such as excessive body hair, increased sweat secretion, obesity, and poor personal hygiene should first be considered. Then, it is necessary to differentiate between:

• a non-irritated pore
• an acutely abscessing form
• a chronically secreting form

Ultrasound, CT, or MRI are generally dispensable.

• In the case of a non-irritated porus, the patient is informed about the course of the condition, particularly that spontaneous healing is not possible, and that very rarely malignant degeneration can occur. The patient is re-scheduled for annual check-ups.
• In the case of the acutely abscessing form, the typical signs of a soft tissue abscess with local redness, warmth, and swelling can usually be detected paramedian to the anal cleft. The acutely abscessing form requires immediate therapy, and initially, a surgical abscess drainage (1-2 cm incision under local anesthesia) should be performed. In addition to checking tetanus protection, a calculated oral antibiotic therapy (e.g., Moxifloxacin) should be initiated. The wound should be checked daily until surgery, and definitive surgical treatment should occur after five to seven days.
• In the case of the chronic form of pilonidal sinus, the fistula should be probed with a button probe and flushed with saline. Until surgery, care should be taken to prevent occlusion of the fistula opening and subsequent abscess formation.

• Explanation of the various surgical procedures: Karydakis procedure, rhomboid excision with Limberg flap, radical excision of the sinus with subsequent secondary wound healing.
• Recurrence: The recurrence rates of all methods are reported to be approximately 4%.
• Wound dehiscence or abscess formation
• Bleeding
• Cosmetically disturbing changes in the gluteal region
• Impairment of skin sensitivity