DEFINITION : Pilonidal Sinuses, Hair Cyst, Pilonidal Disease and Pilonidal Abscess are all related to the same condition (a latin word, Pilo meaning hair + Nidus meaning nest + Sinus meaning a passage leading to a cavity containing pus). A Pilonidal Sinuses usually, but not necessarily,contains a hair strand or hair nests and varies from a few strands of loose hair to tens of thousands of strands which are encapsulated in a thick walled cyst (see attached photographs). Sometimes, loose hairs are visible and protruding out through the opening of the sinuses. It is a common disease and affects people from the age of puberty up to forty. It is rare before puberty or over the age of forty. It is far more common in males than in females and especially common in hirsute males. The Sinuses are found in the midline skin at the top of the cleft between the buttocks. In my opinion, the causes are either acquired or congenital. In the congenital type, it is due to congenital anomalies and are certainly related to the incomplete closure of the neural canal during development of the embryo. Therefore, these pits are present at birth, initially very small and invisible. They growand enlarge as the individual ages and they become very clear when the individual approaches puberty. Their number varies from one pit to ten pits. They stop growing in size when the individual’s growth stops for example around eighteen years old. In this respect, they are not “Hamertoma” lesions but mimic Hamertoma. These pits remain silent and asymptomatic for the rest of the individual’s life and the person is not aware of their presenceunless and until it causes problems.In tens of years of my active surgical practice, when I examine patients in the left lateral Sim’s position for ano-rectal diseases and perform proctoscopy and sigmoidoscopy, I discover patients with numerous small pits in the midline and the patient is not aware of them as per the attached photographs.
The midline skin of the natal cleft is tethered to the tail bone (coccyx), when infection and abscess formation takes place, it will be extremely painful as there is little space for the abscess to expand due to this tethering.
In my opinion, two mechanisms take place for the development of the track of sinuses which are located deep under the skin. The first mechanism, during walking, the motion of the buttocks rubbing together causes shed hairs from the scalp and back to be driven directly into the pre-existing dimples (pits). The second mechanism for the development of deep under the skin sinus tracks is that when the individual stands up from the seated position, the buttocks approximate to each other causing negative pressure in these pits which have already become deeper over the years. This negative pressure sucks the hair into the track particularly in males with large and fatty buttocks.
SYMPTOMS AND DIAGNOSIS : Because of the anatomic site i.e. the lowest part of the back, the proximity of the lesion to the back passage, the presence of warmth and moisture in this area, the frequent presence of fluff, fibre from cotton and wool undergarments, lint, shedding of billions of dead skin cells, and sometimes, lack of hygiene, all are predisposing factors in the development of infection especially in teenage males involved in sports. When an infection develops, these substances and/or the hair acts as the foreign bodies/blockage thus preventing the clearance of infection. The end result is chronic infected holes (sinuses), or a chronic abscess that flares up after a few days into an acute abscess with swelling of various sizes, redness, exquisite tenderness, hotness and pain which varies between a dull ache and acute unbearable throbbing pain preventing the patient from walking, sitting or lying on his back. I have seen patients coming to my surgical clinic limping and screaming from the pain. In a lesser degree, if the patient is lucky, the abscess will burst with immediate relief of pain, but may reoccur unexpectedly sometime in the future which could be weeks or months later with increasing disability, anxiety and depression largely due to the continuous soiling of the underwear and foul odour as well as a low morale especially in teenagers and young adults.
TREATMENT : The only certain and permanent cure is Surgical Operation:
1) If it is an abscess, a surgical operation should be done as soon as possible as an emergency, to evacuate and drain the abscess cavity. An elective surgical operation is necessary a few weeks later when the inflammation subsides.
2) For a permanent cure, planned and elective surgical operation is the only definitive procedure to ensure non-recurrence. This totally depends on the skill and expertise of the Surgeon, provided the patient adheres to the post-operative instructions. In my surgical out-patient clinic in Dubai, I have performed around one hundred and twenty (120) surgical operations on Pilonidal Sinuses and Hair Cysts in the operation theatre of the clinic under pre-medication and local anaesthesia (Lidocaine 2% with Adrenaline 1/80,000 or 1/100,000). In all the cases, healing was by granulation and epithelialization (secondary intention). Nearly all patients stayed in the clinic overnight. Several cases were really bad recurrences. The results were no recurrences. All are documented with numerous photographs. Almost all were followed-up for one year i.e. review every three to four months for one year.