PILONIDAL SINUS EXCISION - small incision & closed wounds

(Drain and close pilonidal abscess - no need to leave huge open wound!)

Pilonidal Sinus Disease

Pilonidal sinus disease is a tract with an opening on the skin leading to a collection of hair. It most commonly occurs in the natal cleft(in the midline between the buttocks) but it can also occur elsewhere - eg in hands(especially in barbers) and around the belly button(especially if one has a deep umbilical stump).

How Pilonidal Sinus Develops

The natal cleft is often moist. The hair shafts (which under the microscope look like barbs) drill into the soft moist skin when one sits(the buttocks can also create a suction type effect - sucking in the hairs deeper). This may be then lead to localized inflammation(folliculitis) which further weakens the skin. Over time a nest full of hair forms under the skin. This may be connected to the outside skin by a small sinus tract.

Interestingly, the sinus may also be congenital(present from birth) in some people. This may explain why people who are not hairy develop pilonidal sinus disease too.


An abscess can develop when an infection forms within this nest of hair and the tract is not able let the pus drain out. This can be very painful. In addition, it may be complicated by sepsis (with high fever) and surrounding skin infection(cellulitis).

Dr Cheah's Mini-excision 

This is Dr LP Cheah's preferred first line approach (even if there is a pilonidal abscess) - it is an improvement of the Bascom operation he learnt from Paul Kitchen., using much shorter incisions. It is a simple and safe surgery to perform.  

There is a short 1cm incision to excise around the sinus opening - and also the underlying sinus tract. Nest of hairs would be removed if present. 

Another short 1cm incision is usually made over an underlying abscess or abscess cavity (this is often filled with clumps of hairs too).

The tract in between in debrided 

Small undermining incisions is used to lift up the excision scar in midline(mini cleft lift) - sometimes a local flap is also used to minimize the scar in midline

Wounds are closed with dissolvable sutures - there are usually just 2 short 1cm scars

This can be done under local anaesthesia for patients without private insurance. 

Postop - Time off work - usually just the day.  Dissolvable sutures usually fall off in 6 to 8 weeks. Antibiotics may be needed if there is pus present.

If an abscess has been drained - the sutures may be kept loose to allow ongoing drainage of fluid collecting in the abscess cavity. May need to redress the area with a dressing that can absorb the ooze - sanitary pads work well here. 

Need to keep the area free of new hairs regrowing - laser hair removal is best. This surgery unlike the bigger Karydakis surgery, does not remove the predisposing factors (deep natal cleft, hairs, moist cleft) - on sweaty days when one is sitting for prolonged periods, one can try stuffing a toilet paper into the cleft from time to time to flatten the cleft a bit and absorb the moisture.

Review in 2 to 3 months postop 

Modified Karydakis Surgery

The principles of surgery for pilonidal sinus disease is :

(i) To excise the sinus tract and the nest of hair

(ii) To leave a scar away from the midline to reduce the risk of recurrence

(iii) To make the natal cleft shallower to have less chance for hair to reaccumulate or be sucked inwards

The operation involves:

1. Marking out the area prior to making the incisions and putting in local anaesthetic around the area - a large ellipse of skin and subcutaneous tissue is excised

2. Excising the sinus tract and the nest of hair. This is done in a way which will leave the resulting scar away from the midline

3. Raising a large local flap of skin to cover to allow closure of the wound - ensuring that the wound stays away from midline and the natal cleft becomes shallower

Dr Cheah usually recommends this operation as the first operation in certain complicated pilonidal sinus disease.

Other options:

1. Direct large excision and closure - but this will leave a scar in the midline and has a high recurrence rate (20-30% - info from the Australian Colorectal Society website)

Dr Cheah's mini-excision leaves shorter scars and heals faster

2. Excision and closure with other types of flaps including rhomboid flaps- again the principle is the same as the Modified Karydakis operation

3. Excision and wound left open - this will take months to heal and patients have to undergo repeated dressing changes. Unfortunately this is still been done in many places. Some patients end up being on a Vacuum dresssing for months.  

Please come to see Dr Cheah asap if you have a pilonidal sinus abscess and would like to have short incision and a closed wound. There is no need to go through weeks of dressing changes! (Dr Cheah would rather see you before the surgery than after). It is a surgical dogma to have to lay open an abscess - Dr Cheah has been closing pilonidal sinus abscess wounds for a number of years with good results for his patients. 

4. Excision of pit/sinus tract, removal of hairs and cleaning of the tract(Bascom type operation) - this is a smaller operation hence recovery is quicker. This can be done in the rooms under local anaesthesia. Advantages: smaller wounds, less pain postop, no deformity to buttocks. Disadvantages : The drawback is a higher recurrence rate hence close long term follow up is essential. There is a variant which uses ultrasound to localize the abscess cavity

Dr Cheah's Mini-excision is his modification of this - using shorter incisions. 

5. Endoscopic Pilonidal Sinus Surgery Advantages: smaller wounds, less pain postop, no deformity to buttocks. Disadvantages : More extensive dissection, extra incisions for camera/scope

Dr Cheah's Mini-excision is using this technique directly - without need for extensive dissections. Based on his experience, infected tissues and hairs under the skin are resected using the short skin incisions

Risks of Surgery

1. Recurrence - the Modified Karydakis has a very low recurrence rate(1-3%). Mini-excision - like laying open(but without the disadvantage of having an open wound for months that needs daily dressings)

2. Bleeding - there is a risk of a small amount of bleeding and bruising. During the operation, any bleeding blood vessels would be cauterized to reduce the risk of a haematoma developing after the operation.

3. Wound infection / breakdown - this would need treatment with antibiotics and occassionally surgical drainage. This may lead to an area that would take longer to heal. To reduce the risk, intravenous antibiotics is given at the time of surgery.

4. Pain in the wound as with any other cuts.

Useful link: www.pilonidal.org


Dr George Karydakis was a surgeon from Greece who has performed thousands of pilonidal sinus surgery using the technique he first described in the Lancet in 1973.

Mr Paul Kitchen is the surgeon who coined the term "Karydakis operation" in his publication in the ANZ Journal of Surgery in 1981. He has had the opportunity to learn from Dr George Karydakis himself(in London in 1973) and also from Dr John Bascom(and his son Dr Tom Bascom) in Oregon, US. He has performed over 300 pilonidal sinus surgery(probably the highest number in Australia) since 1973. He is a fantastic teacher of surgery. He also has an amazing knowledge of theology and can speak in fluent Arabic(from years of charity work in the Middle East)

The author, Mr LP Cheah, has had the privilege of training under Mr Paul Kitchen - a Senior Lecturer at the University of Melbourne and senior surgeon at St Vincent's Hospital.  To date, he has performed over 600 pilonidal sinus surgery.

If you are from interstate and is seeing Mr LP Cheah in the rooms with a view of having a Mini Excision , please fax the referral for a prior phone consult. 

If you have a pilonidal sinus that is discharging and potentially turning into an abscess, please fax referral to 90699480 for an urgent phone consult.