Pilonidal sinus

A pilonidal sinus is a subcutaneous sinus containing hair
Lined by granulation tissue rather than epithelium
Usually occur in the natal cleft

Picture provided by Miss Avril Chang, Central Middlesex Hospital, London, United Kingdom

Picture provided by Dr Ovidiu Florica, Royal Melbourne Hospital, Melbourne, Australia

Also seen in interdigital clefts, face and axilla
Usually seen in young adults.
Rare after the age of 40 years
Male : female ratio is 4:1

Aetiology

It is generally believed to be an acquired condition
Inflamed hair follicles in the cleft result in abscess or sinus formation
Hair becomes trapped in cleft and enters sinuses
Results in a foreign body reaction and perpetuates sinus formation
80% present with recurrent pain
80% present with a purulent discharge

Treatment

Consider methylene blue injection to identify all of the tracts
Antibiotic prophylaxis may be of benefit
Options available included:
- Excision and healing by secondary intention
  - Requires regular wound dressing and shaving
  - Produces 70 - 90% healing at 70 days
  - 5-15% recurrences rate
- Excision and primary closure
  - Produces 70% healing at 2 weeks
  - 20% develop wound infection
- Lord's procedures
  - Involves excision of pits, removal of hair and brushing of tracts
  - Produces 80-90% healing
- Phenol injections
  - Produces 60 - 70% healing
- Skin flap procedures (e.g. Karydakis procedure)
  - Aim to flatten natal cleft and keep scar from midline
  - In expert hands produces good results
  - Failure rates as low as 5% have been reported

Bibliography

Bascom J U. Pilonidal sinus. Curr Pract Surg 1994; 6: 175 - 180.

Duxbury M S, Blake S M, Dashfield A, Lambert A W. A randomised trial of knife versus diathermy in pilonidal disease. Ann R Coll Surg Engl 2003; 85: 405-407.

Khaira H S, Brown J H. Excision and primary suture of pilonidal sinus. Ann R Coll Surg Eng 1995; 77: 242-244.

Kitchen P R B. Pilonidal sinus: experience with the Karydakis flap. Br J Surg 1996; 83: 1452-1455.

Peterson S, Koch R, Stelzner S et al. Primary closure techniques in chronic pilonidal sinus. a survey of the results of different surgical approaches. Dis Colon Rectum 2002; 45: 1458-1467.

Senapati A, Cripps N P J. Pilonidal sinus. In: Johnson C D, Taylor I. eds. Recent advances in surgery 23. Edinburgh, Churchill Livingstone, 2000: 33-42.

Senapati A, Cripps N P J, Thompson M R. Bascom's operation in the day-surgical management of symptomatic pilonidal sinus. Br J Surg 2000; 87: 1067-1070.