Pilonidal disease

Spectrum of diseases - ranging from a simple asymptomatic sinus, to a large, complex open wound.

Epidemiology

• Typically mid-to-late 20s
• Men

Risk factors

• Seen in hairy people with deep natal clefts
• Poor hygiene
• Prolonged sitting (44%)
• Excessive sweating
• Obesity (37%)
• Local irritation or trauma (34%)

Pathophysiology

• Thought to be acquired, rather than congenital
• Most likely results from shed hairs being drawn subcutaneously through pre-existing pits
• Leads to local trauma and inflammation, and subsequent abscess
• Sinuses generally extend cephalad from the skin

Presentation

• Majority present initially with a pilonidal abscess, cephalad to the natal cleft
• Presence of midline pits is the hallmark finding

Differentials

• Hidradenitis suppuritiva
• Anal fistula
• Neoplasm (rare)
• Sacral pressure area

Principles

• Control sepsis
  • Drain acute abscesses
  • Definitive surgical management in the face of active infection is to be discouraged
  • Primary closure will likely fail in the setting of infection
• Disease severity and operative approach should match
• Avoid too much excision
  • Too deep of an excision leads to recurrence/treatment failure
• Unroof all disease, debride granulation tissue, remove hair
• Use an off-midline excision and closure when possible
  • Minimise amount of wound in midline
• If wound is closed, minimise tension
• Change the anatomy, flatten the natal cleft
  • Deep natal clefts contribute to recurrence

Treatment

Non-surgical

• • Shaving
  • Hygiene
  • Antibiotics for inflammation without abscess
  • No benefit to laser hair removal in studies, but not unreasonable to encourage it, along with other depilatory agents

Surgical

• • It is possible to find data demonstrating the superiority of any one procedure over any other procedure
  • Decision for definitive elective surgery should be based on the severity of symptoms as perceived by the patient, rather than any criterion such as the number of abscesses
  • Principle
    • Destruction of all sinus tracts and pits
    • Normal tissue preserved as much as possible to facilitate wound management (higher volumes of excised tissue associated with increased complication and recurrence rates)

Simple procedures

• • Simple abscess drainage
    • Indication: acute pilonidal abscess
    • Typically, the abscess 'points' to one side of natal cleft - incise abscess cavity just off midline in this direction
    • Unroofing and curettage leads to better resolution rates than just I+D (96% vs 79%) and fewer recurrences
    • Break up all loculations, drain all purulence
    • Don't excise pits - no clinical benefit in acute setting
    • Cease antibiotics unless cellulitis
    • Initial packing, but not necessary after first day
    • Once or twice daily showering with soapy water
    • Typically closes in 1-2 weeks
    • Follow-up:
      • Recurrence rate of 10-55% - multiple pores and lateral sinus tracts associated with recurrence
      • UTD says start regular hair control technique (not razor shaving)
  • Pit-picking and the simple Bascom procedure (Bascom 1 procedure)
    • Indication: mild chronic disease in which primary complaint is midline pits, or there is a small wound off-midline.
      • This is a good option for when a full resection would be a major undertaking and is not justified
    • Components (can do both):
      • Excise central pits with a punch knife of appropriate size - insert to full depth, remove hair and debris, and close primarily (3-0 vicryl)
      • For off-midline disease, make a 2-3cm incision just lateral to indurated area. Dissect subcutaneous towards midline pits, and excise the lot. Close the superior and inferior aspects, then leave the middle open to pack (comes out next day).
    • Heals in 1-3 weeks
  • Excision with or without primary wound closure
    • Apply above principles - wound off midline, as small as possible
    • Primary closure is associated with faster healing (14 vs 60 days), but higher recurrence (8.7 vs 5.3%). Infections were low in both groups.
    • Don't try it in patients with extensive and destructive disease
    • Healing takes weeks to months - can use negative pressure dressings
    • NPWT is more useful for larger defects. Slightly improved time to complete healing in NPWT compared to standard therapy (84 to 93 days).

Intermediate procedures

• • Excision of or unroofing of disease in the midline (or just off midline) followed by subcutaneous flap mobilisation and tension-appropriate closure +/- drain
    • Healing rates of >90% and low recurrence rates have been reported
  • Karydakis flap
    • See separate topic
  • Cleft lift procedure (Bascom 2 procedure)
    • Mark the 'safe zone' by pushing gluteal fold together and marking where tissue touches in the midline
    • Excise disease, with scimitar shape of lower edge. Leave the bulk of deeper fatty tissue in place under the skin disease.
    • Mobilise flap towards opposite 'safe zone', about the thickness of a breast flap (3-5mm), but thicker on the inferior edge. This mobilisation flattens the cleft and allows it to close.
    • Close wound in layers - deep layer with 3/0 Vicryl to obliterate dead space, then Monocryl for skin
    • Mostly won't need a drain, but if you do, have it in between the skin and deep layers of sutures

Complex procedures

• • Wide excision of severely disease tissue followed by mobilisation of lipocutaneous flap
  • Rhomboid flap (modified rhomboid or Limberg flap)
  • If there is significant lower back disease, such that mobilising a rotational flap would be impossible, it's ok to still do the rhomboid flap and treat the upper disease as an open wound, with debridement and healing by secondary intention

Post-op

• Post-op shaving MIGHT be beneficial (UTD says yes)
• Avoid prolonged sitting
• Lose weight
• Perineal hygiene