Pilonidal sinus and pilonidal cyst, collectively known as pilonidal disese, is a chronic sinus or cyst within the soft tissue of the intergluteal fissure of the sacrococcygeal region and is characterized by the presence of hairs. It can also present as an acute abscess in the sacrococcygeal region, which is punctured and forms a chronic sinus tract, or heals temporarily and eventually punctures again, and can recur. The cysts are accompanied by granulation tissue, fibrous hyperplasia and often contain a tuft of hair. Although the disease can be seen after birth, it mostly occurs after puberty at the age of 20-30 years, when symptoms appear due to increased activity of the hairy lipid glands.
Etiology
The true etiology is unknown and there are two theories.
1. Congenital: Inclusion of the skin due to residual medullary canal or developmental malformation of the sacrococcygeal suture. However, antecedent lesions of hair hiding disease are rarely found in infants with a midline position in the superficial posterior anal recess, while they are indeed more common in adults.
2. Acquired.
It is believed that sinuses and cysts are granulomatous diseases caused by injury, surgery, foreign body irritation and chronic infection. Recently, it has been confirmed that hairs entering from outside are the main etiology. The intergluteal cleft has a negative attraction that allows penetration of shed hairs subcutaneously. Excessive hair within the fissure is too long, the top of the hair has a filtering and softening hair skin effect, the hair penetrates into the skin, forming a short channel, later deepening into a sinus, the hair root shedding into the sinus can also make the hair stem penetrate, during the pathogenesis of the movement can be seen to change, but only half of the cases can be found hair, the disease is seen in patients with multiple hair flat, sebaceous over activity, the intergluteal fissure is too deep and the buttocks are often injured. The skin of the sacrococcygeal region of automobile drivers is often subject to long-term upsets and injuries, which can cause sebaceous gland tissue and debris to accumulate in the capsule and cause inflammation. Common germs are anaerobes, staphylococci, streptococci, and E. coli. rainsbury and southan analyzed stationary hide hair disease with less than half of the individual bacteria and 58% of the anaerobes. Surprisingly, staphylococci were uncommon and most aerobic bacteria were gram-negative.
Tibetan hair cysts are often asymptomatic in the absence of secondary infection, except for sacrococcygeal prominence, and in some cases pain and swelling felt in the sacrococcygeal region. Usually the main and first symptom is an acute abscess in the sacrococcygeal region with acute inflammatory features such as local redness, swelling, heat and pain. Most of them break out pus automatically or the inflammation subsides after surgical drainage, and a few drainage openings can be completely closed, but most of them show recurrent episodes or frequent flow of water and form sinus tracts or fistulas.
In the quiescent phase, a small irregular hole with a diameter of about 1 mm-1 cm can be seen in the midline skin of the sacrococcygeal area. the surrounding skin is red and hardened, often with scarring, and some hairs are visible. The probe can probe into 3-4mm, some can probe into 10cm, and can discharge dilute light smelly liquid when squeezed. In the acute phase, there are acute inflammatory manifestations, tenderness and redness, more purulent discharge, and sometimes abscess and cellulitis.
Clinical manifestations
Zebra cysts are often asymptomatic if there is no secondary infection, only sacrococcygeal protrusion, and some feel pain and swelling in the sacrococcygeal area. Usually the main and first symptom is an acute abscess in the sacrococcygeal region with local acute inflammatory features such as redness, swelling, heat and pain. Most of them break out pus automatically or the inflammation subsides after surgical drainage, and a few drainage openings can be completely closed, but most of them show recurrent episodes or frequent flow of water and form sinus tracts or fistulas.
In the quiescent phase, a small irregular hole with a diameter of about 1 mm-1 cm can be seen in the midline skin of the sacrococcygeal area. the surrounding skin is red and hardened, often with scarring, and some hairs are visible. The probe can probe into 3-4mm, some can probe into 10cm, and can discharge dilute light smelly liquid when squeezed. In the acute phase, there are acute inflammatory manifestations, tenderness and redness, more purulent discharge, and sometimes abscess and cellulitis.
Differential diagnosis
It should be differentiated from boils, anal fistulas and granulomas. Boils grow on the skin, protrude from the skin, and have a yellow top. Canker sores have multiple external holes with necrotic tissue inside. In anal fistula, the external opening is close to the anus, the fistula travels in the direction of the anus, there are cords on palpation, there is an internal opening in the anal canal, and there is a history of anorectal abscess. In contrast, the direction of travel of the hidradenous sinus is mostly cranial and rarely downward. Tuberculous granuloma is connected to bone, and X-ray reveals destruction of bone and tuberculous lesions in other parts of the body. Syphilitic granuloma has a history of syphilis and is seropositive for syphilis.
Surgical treatment method of hidden hair sinus
Surgery is the main treatment method, but it is contraindicated in the presence of inflammation and should be performed after the inflammation has subsided. The surgical methods are as follows.
1. Excision and one-stage suture: surgical excision of all diseased tissues, free muscles and skin, and complete suturing of the wound to enable one-stage healing. To eliminate deep intergluteal fissures and their negative pressure, reduce wound dehiscence, hematomas and abscesses, Z formation is feasible. It is suitable for cysts and small uninfected sinus tracts on the midline with a recurrence rate of 0%-37%. The advantage is that the healing time is short, the scar formed within the intergluteal fissure is soft and mobile, and there is soft tissue between the scar and the sacrum that can tolerate injury.
2.Excisional partial suture: The diseased tissue is excised and the skin on both sides of the wound is sutured to the sacral fascia so that the majority of the wound heals in one phase and the middle part of the wound is healed by granulation tissue. It is suitable for cases with many sinus openings and sinus tracts, and the effect is the same as excisional one-phase suture, but the healing time is longer.
3.Excisional wound open secondary suture: Applicable to cases with severe infection and cases with infected wound incision and drainage occurred in the first stage suture.
4.Open excisional wound: Applicable to cases where the wound is too large to be sutured and the surgery is recurrent. The operation is simple, but the healing period is long and the scar formed is extensive, with only a thin layer of epithelium that sticks to the sacrum, and the scar is prone to rupture if there is an injury.
5.Pouch suture: The surface part of the sinus wall and the upper cover skin are excised, and the wound is created with intestinal thread or absorbable artificial suture to promote healing. Satisfactory results can often be seen with careful postoperative care. It is mostly used for unresectable cases or recurrent hidrocystic sinuses.
Non-surgical treatment of the hidrocystic sinus
The sacrococcygeal fossa does not require treatment because it is only a depression in the sacrococcygeal joint, the lower part of the sacrum and the tip of the coccyx, without any symptoms and of no clinical importance.
If infection occurs in sacrococcygeal sinus and sacrococcygeal swelling, anti-inflammatory treatment should be performed to keep local cleanliness, and if abscess is reproduced, incision and drainage should be performed. However, the skin and subcutaneous tissue of sacrococcygeal region are thicker and harder, and there is no obvious performance in the early stage, and the inflammation often spreads to the surrounding tissues to cause cellulitis. Deep tissue necrosis should be incised and drained at an early stage.
Sclerotherapy is the injection of corrosive drugs into the sinus tract to destroy the sinus and intracapsular epithelium, so that the cystic cavity and sinus tract are closed. Since 1960, someone applied phenol solution injection therapy, but not many applicants, because the application of pure phenol solution, the pain is severe, later changed to 80% concentration, and under general anesthesia; sinus injection gel to protect the surrounding skin. hegge (1987) with 80% phenol solution 1 to 5ml slowly injected into the sinus, about 15min, slow injection can prevent complications, such as skin burns, fat necrosis or severe pain. Stansby (1989) injected 80% phenol solution into the sinus under general anesthesia, kept it for 1 min, scraped the sinus tract, and repeated it 3 times, treating 4 cases of aseptic abscess and 1 case of bee sick fossa in 104 cases. Tissue inflammation, no other complications. Compared with 65 cases of surgical resection, the treatment rate; resected is 86%, phenol injection is 75%; follow-up average 8 months (3 months to 4 years), resected 10 cases of recurrence injected 12 cases of recurrence.
Prognosis
Carcinomas occurring in the hidradenous sinus are rare. The lesions are mostly well-differentiated squamous cell carcinomas. Wound changes should give rise to suspicion of carcinoma, such as ulcers that break easily and grow quickly, out of sedan and mycobacterial-like margins. Extensive excision should be preferred. As the wound is widely treated with skin graft or flap. The prognosis is not good if there is metastasis, and the 5-year survival rate is 51%. The recurrence rate is 50%. Metastases in the abdominal and femoral lymph nodes are found in 14% of cases at the time of initial diagnosis.