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Content provided by Jon Lund
Clinical Associate Professor, School of Graduate Entry Medicine & Health, University of Nottingham 		 
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Pilonidal Sinus

pilonidal sinus disease showing pits in the midline

1. Definition

1.1 Sinus

A blind ending epithelial lined tract

1.2 Pilonidal Sinus

In Latin, Pilus means hair and Nidus means nest, therefore pilonidal means "hair nest". A pilonidal sinus is an acquired condition where a sinus tract, generally containing hair, forms mainly occurring in the natal cleft but may also occur elsewhere in the body, namely the fingers in barbers, hairdressers and animal groomers and in the armpits. There may be associated chronic suppuration.

2. Epidemiology + Aetiology

  • The incidence is approximately 0.7%

  • Risk factors include

    • More common in Caucasian compared to Africans or Asians

    • Male

    • Age - rare after 40 and before puberty

    • Hirsute

    • Occupations involving sitting

 

3. Pathophysiology

  • Thought to be an acquired process rather than congenital

  • Sex hormones at puberty lead to enlarged hair follicules

  • Plugging of the follicules with hair or keratin leads to folliculitis

  • The follicules rupture in the subcutaneous tissue leading to subsequent abscess formation

  • The result from this is a sinus that connects the skin to a subcutaneous cavity

 

4. Symptoms & Signsa probe can be passed along the subcutaneous course of the sinus

4.1 Symptoms

  • Presentation may be

    • Asymptomatic - noticed by patient or physician

    • As a painful swelling

    • As an abscess

    • Chronic pilonidal disease

 

 

 

4.2 Signs

  • Visible sinus tract or pits in the sacrococcygeal region

  • Those with any abscess

    • Calor (heat)
    • Rubor (Erythema)

    • Dolor (pain)

    • Tumor (swelling)

    • Chronic disease

  • Recurrence following abscess drainage

  • Chronic discharge without presence of an acute abscess

     

 

5. Diagnosis & Investigation 

  • Diagnosis made purely on history and examination

  • No investigations are required

6. Management

Varies according to presentation

6.1 Aymptomatic disease

  • Conservative measures can be employed

  • Exemplary hygiene must be employed

 

6.2 Acute pilonidal abscess

  • Incision and drainage of abscess and curettage of cavity

  • Incision should be laterally, away from the midline due to poor wound healing in the midline

  • Not a curative procedure

 

6.3 Chronic pilonidal disease

  • Numerous surgical options

  • No surgical option has proven to be superior to the other

6.3.1 Fibrin Glue

fibrin glue used to treat pilonidal sinus disease
  • Curretage followed by injection of fibrin glue

  • Promising early results with improved pain scores and earlier return to normal daily activities

  • Gallery of gluing pictures is here

    6.3.2 Excision of sinus tract

    • Excision of the pits down to presacral fascia
    • Minimal removal of surrouding tissues
    • The wound may be closed primarily if clean – patient should be warned of the risk that closure may not be successful
    • In the presence of sepsis, the wound should be left to granulate

    6.3.3 Bascom's lift

    • Lateral incision made
    • Sinus excised and skin closed primarily off the midline and the natal cleft flattened

    6.3.4 Rhomboid (Limberg) flap

    • Used for advanced/recurrent disease where local excision not an option
    • Diseased area is excised down to the facia in a diamond shape
    • Unaffected skin and fat is marked out and the flap mobilised
    • The flap is rotated into the defect and sutured into place
    • Patient needs to have a drain postoperatively and be nursed on side/front for 72 hours or so. Can be painful post op. Low recurrence rate

    6.3.5 Karydakis procedure

    • Asymmetrical ellipse drawn onto natal cleft prior to incision including the lateral tracks in the wider half of the ellipse
    • Skin incised over markings to pre-sacral fascia
    • Flap created by undermining one side until the wound edges can be approximated

    Further Reading...

    Fibrin Glue
    • Fibrin Glue in the Treatment of Pilonidal Sinus: Results of a Pilot Study Diseases of the Colon & Rectum 2005;48:1094-6 [link]
    • Fibrin glue may be better than surgery for pilonidal sinus: Results of a prospective, randomized, controlled trial and 2-year follow up Diseases of the Colon and Rectum 2008;51:710-11 [link]
    Review of treatment of pilonidal sinus disease Sacrococcygeal pilonidal disease 2008 Colorectal Disease; 10: 639-650 [link]