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Pilonidal sinus
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Dr.Barin Bose MS, FACRSI .
Surgeon , Coloproctologist and GI Endoscopist.
Jabalpur Hospital and Research Centre.
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In Latin pilus means hair and nidus means nest. Pilonidal sinus is a, minor surgical condition though benign it causes much distress to the patient. It requires a radical surgical procedure with a long stay in hospital, discomfort and loss of earning.

It is commonly an infection in the intergluteal (natal) cleft. This disease consists of a sinus situated a short distance behind the anus which generally contains hairs. It is a disease of second and third decades of life. Men are more commonly affected than women. Majority are dark hairy subjects. Surprisingly the condition is rare in black Africans. The condition rarely occurs in the blonds. The condition occurs in dark haired white race persons whose hairs are stiffer than the silky blonds.

It occurs in young hairy men who have large buttocks and deep natal cleft. Patients are less than 40 years of age and have a long sitting occupation. It was so common among jeep drivers in 1935 to 1945 war that it was known as "jeep bottom".

It occurs in the sacrococcygeal area in midline about 5 cms behind the anus . Even if multiple sinus do not extend deep in the sacral fascia, thus preventing their penetration into the bone . Loose hairs are mostly found in the sinus hence the inflammation is a combination of an infection and foreign body reaction. The sinus extend mostly cephaloid and branches out laterally. Rarely it extends caudally, then it become difficult to differentiate with anal fistula.

Aetiology : (1) Dermal theory - The pilonidal disease is either a sequestration dermoid or implantation dermoid. The sinus which form in the web of fingers can be explained on the basis of implantation dermoid.
(2) Theory of acquired origin - Patey and Scarff in 1946 suggested that the sinus was of acquired origin since it - (a) Recurred quite frequently. (b) It does not contain hair follicle. The hairs are the secondary invaders as hair is present in only half of the Pilonidal abscesses.
(3) Rolling theory - Bearly suggested in 1955 that the rolling movement which takes place between the contiguous surfaces of the buttocks at the cleft results in hairs being detached from the skin and twisted into bundles. This bundle of hair lying along the cleft then drills its way through the skin. Once the skin is punctured further penetration is helped by the suction mechanism. The separation of buttock during sitting or bending tends to lift the skin at the base of the natal cleft away from the underlying sacrococcygeal fascia thus creating a negative pressure. This negative pressure tends to suck the bundles of hair deep into the sacrococcygeal fascia.
Presentation - The symptoms are due to inflammation in the sinus. Pain swelling and pus discharge is the usual symptoms.
¢ Patient present with acute abscess usually single.
¢ Chronic Pilonidal sinus presents with continuous or intermittent pus discharge or nonhealing midline ulcer with or without pain.
Condition resembles a foreign body granuloma since the tract is lined by granulation tissue.

Diagnosis - It occurs in young hairy adult male , who have large buttocks and a deep nalat clift. The affected area is soft oily skin which is lacking in good hygiene.
Differential Diagnosis - It is to be differentiated from -
¢ Furuncle.
¢ Carbuncle.
¢ Anal fistula.
¢ Hidradenitis suppurate.
Squamous cell carcinoma and basal cell carcinoma have been reported in the sinus tract.
The sinus extends upwards and forwards but do not reach the bone. It ends blindly before reaching the bone. It mostly occurs in the midline in sacrococcygeal area, about 5 cms from anus.
Other sites of the disease are -
¢ Finger web.
¢ Axilla.
¢ Presternal.
¢ Perineum.
¢ Suprapubic region.
¢ Nipple.
¢ Neck.
¢ Groin.
¢ Anal canal.

Conservative Treatment: Patients reporting for the first time with mild symptoms can be cured by conservative treatment. It consists of cleaning of the tract and removing all hairs from the area. Washing the area with detergent and water and then applying witch hazel and alcohol in equal parts. Long sitting and driving is avoided. Depilation of hair, frequent sitz bath, keeping the area dry. Injection of Phenol is tried in early sinus with one or two openings or recurrence after surgery.
Operative Procedures - It should be performed when inflammation has been controlled by antibiotics. Patient has been placed in prone jack knife position. Methylene blue is injected into the sinus to color all the tracts. Then following can be done -
(1) Lay open the tract, remove all the debris and hairs, then suturing the edges of the tract with the skin , thus marsupalising the tract.
(2) Excise all the tract as stained by blue dye. Secure good haemostasis by diathermy and sutures. Then close the subcutaneous tissue and skin after keeping a Romovac drain for 48 hours.
(3) Excise all the tract as stained by blue dye.Secure good haemostasis by diathermy and sutures. The wound is packed and dressed ,following day the whole dressing and pack is removed and then daily dressing is done till the wound heals by granulation tissue . Ensuring that the wound heals from below. Epithelialisation can be speeded up by skin grafting. Cure rate is high if re entry of the hair is prevented. Chronic Pilonidal sinus is treated keeping in mind the high rate of failure / recurrence.
(4) Excision - Conservative excision - A midline elliptical incision is made to include all the sinus and whole of the tract is excised.
(5) Wide radical excision - Is done in an assumption that this was the only way to prevent recurrence, though it was not always necessary. The wound may be left open for secondary healing.
To accelerate healing the following procedure is done -
¢ Primary closure - Straight midline closure or Z - plasty.
¢ Partial closure or secondary closure.
¢ Skin grafting .
Other Operative Techniques - (1) Excision of coccyx to reduce suture line tension.
(2) Skin flap advancement to obliterate the natal cleft
(3) Excision of sinus with Z plasty.
(4)Gluteus maximum myocutaneous flap.

(5)Karydakis Technique- The sinus is excised by an eccentric elliptical incision. A flap is mobilized from the medial side of the wound. Sound closure is to one side of the midline.
(6) Bascom's Technique- An incision 2-3cms lateral and parallel to the midline is made and the chronic abscess cavity is drained, freed of the hairs, granulation tissue is curetted. Removal of small midline pits is carried out by a small elliptical incision. The lateral wounds are kept open but the midline wound is closed.
(7)Excision and direct closure- the complete tract with its extension is excised and the cavity is closed with primary sutures. Primary closure with midline scar is associated with recurrence rate of 18%. Where as it is less than 10% when the scar is displaced from the midline.
(8) Bascom's cleft closure Technique- this is used for open midline wounds after failure of surgery. After debridement of the abscess cavity. A full thickness skin flap is excised and advanced (rotated) across the midline to obliterate the natal cleft .
(9) Rhomboid flap Technique- The Pilonidal sinus is excised and a rhomboid flap of skin taken from the adjoining gluteal area is rotated into the resultant defect and completed with primary closure. Disadvantage of this technique is -- (a) blood loss
(b) Flap necrosis (c) Numbness over the flap.
(10) Excision and Saucerisation Technique- The sinus is excised widely and the raw area is left to granulate from the depth and to obliterate the cavity with long healing process.
(a) Long healing process
(b) Long hospital stay of patient.
(c) Persistent nonhealing midline wound.
(d) Wide excision of all the tissue till the sacrum and leaving the wound open to granulate can never be justified.
(11) Marsupialisation- The wound is partially closed by suturing the skin edges to the sacral fascia.
(12) D- Excision Technique - The sinus is excised enblock up to the sacral fascia through a D shaped incision. The flaps are undermined and approximated without any tension.
(13) Using Gluteal muscle myocutaneous flap - It is a complex produce and is used rarely. It produces reliable healing with low recurrence, but requires prolonged hospital stay and is more technically demanding. Loss of such a flap can be a serious complication.
(14) Multiple Z-Plasty Technique - By Dr. Predeep P Sharma . Pune (vide Indian Journel of Coloproctology Vol. 19, 2004 , P.3 to 8 ) Under local anaesthesia and sedation with Medazolam. The patient is kept prone in a Jack knife position with a pillow under the belly to raise the hips.The buttock were strapped with sticking plaster to keep them apart and expose the operative area. The operative area was shaved just before the surgery and suitably painted and drapped. Methylene blue was injected through the mouth of the sinus to stain the entire tract, to enable complete excision of the tract. The area was infiltrated with 2% xylocaine and adrenaline. The mouth of the sinus or the sinuses along with all the congenital pits are encircled with an elliptical incision and the tract is cored out .The congenital pits are encircled and cored out as these pit are the precursor of the sinus. The sinuses are cored out completely, taking care not to enter the tract at any time. A complete excision of the diseased tissue is the key to the success of the operation .Haemostasis is achieved by a bipolar cautry. Skin hooks are applied at either end of the wound and traction is applied, cuts are marked on the skin. The number of cuts depend on the length of the wound from 1 to 5 cuts are deepened till the subcutaneous fat. The flaps are undermined and mobilized. Extensive undermining is avoided to prevent devascularising of the flaps, the flaps are suitably interdigited and sutured. Subcutaneous sutures are applied with Vicryl 4-0 and skin sutures are applied with 5-0 Nylon, interrupted sutures. Drain is avoided if the haemostasis is good. But a Redivac drain is used if the situation demands . A haematoma in the absence of the drain would lead to breakdown of the wound causing relapse. Healex spray is applied to prevent contamination.

Post Operative Care - The patient is put on liquid diet for 3 to 4 days bowel movement is discouraged till then patient is nursed in a prone position for first few days , then gradually moved out of bed. Sitting on the bed is discouraged for 15 days. Patient is discharged on 5th day. Sutures are removed on the 10th day. Followup is done on 7th and 15th day. Then monthly for three months and three monthly for 3 years.

Advantages of Multiple Z-Plasty over single Z-Plasty -
¢ It requires less undermining.
¢ It is done under local anaesthesia.
¢ Blood loss is less.
¢ No necrosis of the flaps.
¢ Absence of numbness of flap which is common with single Z-plasty.
¢ Cosmetic effect is better as the scar does not extend to the buttock.
¢ The side tracts are easily excised as one of the limbs of Multiple Z-plasty. In single Z-plasty it would require a wider ellipse to encompass the side tracts, which would later cause tension on the wound closure.

After Care - The operative area need regular cleaning with soap and water even after the wound has healed, the area should be regularly scrubbed with soap and washed with water to wash away loose hairs. The surroundings should be kept free of hairs by regular shaving.


Cause of Recurrent Pilonidal Sinus -
(1) A diverticulum of the main channel which has been overlooked at the time of primary operation.
(2) New hairs enter the sinus or scar.
(3) When the natal cleft is deformed by scarring. A least trauma causes tearing of the scar. The ulcer thus formed become contaminated with coliform bacteria.