Pilonidal Sinus Disease

A pilonidal sinus is a small tunnel or cavity that forms under the skin, most commonly in the cleft between the buttocks (the natal cleft). The word “pilonidal” comes from the Latin for “nest of hair” — because loose hairs often become trapped in the skin here, causing irritation, infection, and the formation of a sinus tract.

The area between the buttocks is warm, moist, and subjected to pressure — conditions that allow bacteria to thrive. Once infection takes hold, it can create a network of tunnels (sinus tracts) lined with granulation tissue, which are prone to recurring flare-ups.

Pilonidal sinus disease most commonly affects young adults, particularly men. Risk factors include:

• Excess body hair, especially coarse or curly hair
• Obesity or a deep natal cleft
• Jobs involving prolonged sitting (driving, office work)
• Smoking
• Family history of the condition
• Poor local hygiene

Several surgical approaches exist for pilonidal sinus disease. Your surgeon will advise which is most appropriate based on the number and complexity of your sinus tracts, your general health, and your personal circumstances.

Conservative Management

For mild or early cases: meticulous hair removal (shaving or laser hair removal) around the natal cleft, regular washing, and careful wound care can sometimes control the condition without surgery.

Surgical Excision

This involves surgically removing the infected tissue. The wound may be closed with stitches (primary closure) or left open to heal naturally over several weeks (healing by secondary intention). Flap reconstruction (e.g. Limberg or Karydakis flap) may be used for complex or recurrent disease.

Laser Ablation — The Approach Used at This Clinic

For suitable patients, we offer a minimally invasive approach combining seton insertion followed by laser ablation. This two-stage technique avoids large incisions, preserves healthy tissue, and is associated with a faster recovery than open surgery. Both stages are explained in detail below.

Before laser ablation can be performed, any active infection must be controlled and the sinus tract walls need to be prepared. This is achieved by inserting a seton.

What Is a Seton?

A seton is a thin, flexible thread or loop of surgical material that is passed through the sinus tract and loosely tied. It acts as a drain, keeping the tract open and allowing the infected contents to drain away continuously. Over several weeks, the seton encourages the walls of the sinus to become fibrous and well-defined, making them more suitable for laser treatment.

How Is the Seton Inserted?

Seton insertion is a minor procedure, usually carried out under local anaesthetic as a day case. Your surgeon will:

1. Clean and examine the sinus openings in the natal cleft
2. Probe the sinus tract carefully to define its full extent
3. Pass the seton thread through the tract and secure it loosely in a loop
4. Apply a dressing and give you aftercare instructions

The procedure itself takes only a short time. You will be awake throughout but should feel only pressure — not sharp pain. Local anaesthetic is used to numb the area.

Living with the Seton

The seton will remain in place for several weeks (typically 6–12 weeks) until your surgeon is satisfied that the tract is ready for laser treatment. During this time:

• You can bathe and shower normally — gentle washing of the area with warm water is encouraged
• Some discharge from around the seton is normal and expected
• Wear comfortable, loose-fitting underwear and clothing
• Change dressings as directed by the clinic or your community nurse
• Avoid strenuous exercise or prolonged sitting for the first week or two
• You can usually return to desk-based work within a few days

Once the seton has matured the sinus tract and infection is fully settled, the second stage — laser ablation — can take place. The technique used is also called PiLaC (Pilonidal Sinus Laser Closure).

How Does the Laser Work?

A thin optical fibre is introduced along the length of the sinus tract. A controlled burst of laser energy is then delivered through the fibre, precisely destroying the diseased granulation tissue lining the tract. The healthy surrounding tissue is largely unaffected.

The heat generated by the laser causes the walls of the tract to shrink and seal. Over the following weeks, the body gradually absorbs the treated tissue and the cavity closes.

What to Expect During the Procedure

Laser ablation is performed as a day case — most patients go home the same day. It is typically carried out under local or general anaesthetic; your surgeon will discuss the most appropriate option for you.

• The procedure takes approximately 15–30 minutes
• The seton is removed during the laser treatment
• Small surface openings (pits) are curetted (scraped clean) at the same time
• The entry points are usually closed with one or two small absorbable stitches
• A simple dressing is applied before you leave

Why Two Stages?

In most cases, two stages are required because laser ablation works best when the sinus tract is free from active infection and has firm, well-defined walls. Attempting laser ablation in the presence of acute infection significantly reduces the chance of success. In a small number of carefully selected cases, a single-stage laser procedure may be possible — your surgeon will advise you individually.

Immediately After the Procedure

After the laser procedure you will recover in the day ward for 1–2 hours. The nursing team will monitor your comfort and make sure you are safe to go home. You will be given:

• A supply of dressings
• Pain relief medication to take at home
• Written aftercare instructions
• A follow-up appointment date

Going Home

You will need a responsible adult to collect you from the clinic, particularly if you have received sedation or general anaesthetic. You should not drive on the day of the procedure.

Wound Care

Unlike open surgery, laser ablation leaves only small surface wounds. Healing is generally quicker and less uncomfortable. You will need to:

• Keep the area clean and dry in the first 24 hours
• Shower normally from the following day — use warm water and avoid soaking in the bath for the first week
• Pat the area dry gently after washing — avoid rubbing
• Change dressings as instructed — there will be some discharge in the first few weeks, which is normal
• Avoid perfumed products, talcum powder, or harsh soaps around the wound
• A barrier cream may be prescribed to protect the skin

Hair Removal

To reduce the risk of recurrence, it is very important to keep the natal cleft free of hair during healing and long-term. Your surgeon will advise you on the most effective method — this may include regular shaving, depilatory creams, or referral for laser hair removal.

Pain Management

Most patients find pain well-controlled with regular over-the-counter analgesics such as paracetamol and ibuprofen (if suitable for you). Take these regularly for the first few days rather than waiting until the pain is severe. Your surgeon will prescribe stronger pain relief if needed.

Laser ablation for pilonidal sinus is generally well-tolerated and serious complications are uncommon. However, as with any surgical procedure, there are potential risks. Your surgeon will discuss these with you fully before you consent to treatment.

Common — affecting up to 1 in 10 patients

• Discomfort or mild pain around the wound in the first few days — well managed with regular analgesia
• Discharge from the wound for several weeks after the procedure — this is expected as the cavity heals
• Minor local skin irritation or sensitivity around the sinus openings

Uncommon — affecting up to 1 in 100 patients

• Wound infection requiring a course of antibiotics
• Incomplete treatment — residual or incompletely treated sinus tracts may persist, requiring a further procedure
• Delayed wound healing, particularly in patients who smoke or have diabetes