pilonidal sinus Flashcards
definition of pilonidal sinus
latin for nest of hair
abnormal epithelium lined tract filled with hair that opens to the skin surface
most commonly in the natal cleft
obstruction of the natal cleft hair follicles approx 6cm above anus
aetiology of pilonidal sinus
proposed to be caused by shed or sheared hairs penetrating the skin and inciting an inflammatoiry reaction and sinus development
with intermittent -ve pressure drawing in more hair and perpetuating the cycle
ingrowing hair = foreign body reaction = secondary tracks to open laterally +- abscesses with foul smelling discharge
RF for pilonidal sinus
associated with hirsute individuals who spend a long time sitting (known as jeep botton in WW2)
certain occupations predispose - eg hairdressers may develop interdigital pilonidal sinus
young men with excessive body hair
obesity
deep gluteal cleft
poor anal hygeine/local irritation
sedentary lifestyle
FH
epidemiology of pilonidal sinus
common
affecting 0.7% young adults
male more
obese caucasians, Asian, middle east and mediterranean
sx of pilonidal sinus
painful natal cleft
especially if inflammed or superimposed infection
discharging swelling
recurrent
signs of pilonidal sinus
presence of midline openings or pits seen between the buttocks - from which hairs may protrude
if associated with infection or abscess - tender swelling develops that may be fluctuant or discharge pus or bloodstained fluid on compression
fever
erythema
secondary openings may be seen on either side of the midline
pathology of pilonidal sinus
sinus tract is lined with squamous epithelium and extends variable distance into SC tissue, often with branching side channels
hair shafts and foreign body gviant cells seen in associated granulation tissue
tracking of bacteria -> inflammation and the formation of an SC polymicrobial abscess filled with granulation tissue, pus and hair
Ix for pilonidal sinus
none needed for dx
bloods - FBC (raised WCC), fasting glucose - dm
Mx of acute pilonidal abscess
requires incision and drainage (can be done under LA if small), with removal of pus, hair and granulation tissue
cavity is packed (eg with iodine soaked dressings) and changed regularly until secondary closure
AB cover post op usually unnecessary
Mx of chronic pilonidal sinus
pre-op AB
excision under GA with exploration, laying open and removal of tracts (may be identified by staining with methylene blue) +- primary closure
fibrous tissue tracts attatched to sacrococcygeal bone can be divided
wound healing improved if initial incision is not in the midline eg karydakis operation
Bascom technique involves incision lateral to the midline for removal of the chronic abscess cavity with removal of the small midline pits using small incisions that are closes - leaving the lateral wound open
complex tracks can be laid open and packed individually or skin flaps can be used to cover the defect
prevention of pilonidal sinus
good hygiene in area
shaving important in preventing recurrence
complications of pilonidal sinus
pain
infection
abscess
recurrence
prognosis of pilonidal sinus
good with drainage of pilonidal abscess
shaving = cure in many patients
may be recurring problem
usually resolves by age 40
mechanism of pilonidal sinus
sitting/bending hair follicles in vulnerable skin with deep natal cleft, to stretch and break = formation of an open pore or pit
open pores collect debris or broken heaor roots
movement = negative pressure (suction) and further penetration of hair into local subcut tissue = formation of pilonidal sinus
collections = local tissue inflammation within the sinus = abscess/fistulae
RF for pilonidal sinus
young men with excessive body hair
obesity
deep gluteal cleft
poor anal hygeine/local irritation
sedentary lifestyle
FH
