Common anorectal infection under the skin in the gluteal cleft.
- 3:1 male predilection
History
Pilonidal means nest of hair and is derived from the Latin words for hair (pilus) and nest (nidus). Herbert Mayo is credited with the first description of this disease in 1833, and R.M. Hodges coined the term pilonidal in 1880. Buie noted its prevalence in male, military recruits who drove jeeps and thus characterized it as “jeep disease.” Pilonidal disease was most notable during World War II when an estimated 80,000 soldiers became afflicted and lost significant time from active duty.
Aetiology
Risk factors:
- Family history
- Local trauma
- Sedentary occupation
- Obesity
Pathogenic formula (Karydakis GE):
Pilonidal disease = Hair (H) x Force (F) x Vulnerability (V)2
Pathoanatomy
Hair follicles in the gluteal cleft become infected with keratin resulting in local infection and abscess formation while local suction forces cause hairs to enter the infected pit and lodge in the abscess cavity. Secondary pits then result from subcutaneous burrowing of hair and additional hairs enter through the pits.
- Pilonidal sinus (PNS): Sinus tract (small channel), that may originate from the source of infection and open to the surface of the skin.
- Material from the cyst drains through the pilonidal sinus
- A pilonidal cyst is usually painful, but with draining the patient might not feel pain
Pathogenesis:
- Midline pit develops that may be a hair follicle, which has shed its own hair and then allows debris to occupy the pit
- Loose semi-curved roots of hair fall and migrate to the cleft where they become vertically oriented and insert into the pit via their roots
- Foreign body granuloma develops in the subcutaneous fat
- Depth of the natal cleft is associated with anaerobic environment with moisture and pressure that can lead to increased hair insertion
- Direction of the follicle determines the direction of the tract.
Clinical features
May arise in one of three forms:
Acute pilonidal abscess:
Pain, tenderness, swelling, and erythema in the gluteal cleft with/without drainage from the involved area
- Fever, chills, and pain
Chronic pilonidal abscess (draining sinus tracts):
Chronic pilonidal sinus cavity with recurrent drainage due to retained hair and infected residue
- Sinus tracts: intermittent discharge or bleeding
- Opaque yellow (purulent) or bloody discharge from the tailbone area
- Unexpected moisture in the tailbone region
- Discomfort sitting on the tailbone, doing sit-ups or riding a bicycle—any activities that roll over the tailbone area
Diagnosis
Trephine punch biopsy:
Differential diagnosis:
- Dermoid cyst (germ cell tumor)
- Aacrococcygeal teratoma
Management
Conservative management:
- Shaving/depilation (preventive and therapeutic):
- Shave until complete healing has occurred
Surgical management
- Minimal-to-moderate disease:
- Incision & drainage
- Unroofing & secondary healing
- Incision with marsupialisation
- Bascom chronic abscess curettage with midline pit excision (Bascom I)
- Primary closure with flap procedures
- Severe and recurrent disease:
- Karydakis flap
- Bascom cleft lift closure (Bascom II)
- Rhomboid excision with Limberg/modified Limberg flap
- V-Y advancement flap
- Z-plasty
- Gluteus maximus myocutaneous flap
Incision & drainage:
Limited off-midline incision is combined with excising a small ellipse of overlying skin to promote drainage
Unroofing and open secondary healing:
Excision of midline tracts followed by an open wound leads to prolonged healing. Unroofing of the tracts minimizes the midline wound and shortens healing accordingly. This approach is effective in the presence of a concomitant abscess.
Incision with marsupialization:
Opening the sinus tracts in the midline to include any secondary tracts. The posterior and lateral fibrous tissue is then left in situ and sutured to the skin edge or dermis. The goal is to reduce the effective wound healing area thus reducing the time of healing.
Bascom I surgery:
Bascom chronic abscess curettage with midline pit excision
- Midline pits conservatively excised with removal of contiguous hair and debris in pits
- Concomitant lateral incision, parallel to midline wound made to curette debris from cavity connecting sinus pits
- All incisions left open to heal by secondary intention
- Wounds followed closely to remove hair that may gravitate into the wound
- Careful and frequent wound care essential
Karydakis flap:
Bascom cleft lift closure (Bascom II):
Z-plasty:
Negative pressure wound therapy:
