(Originally published in Chinese Journal of General Surgery Luo Yong Wu Wenlin, Diagnosis and treatment of sacrococcygeal hidden hair disease: with a report of 19 cases 2009.18(12):1318-1319.) Sinus tracts and cysts in the soft tissues of the gluteal fissure of the sacrococcygeal region are often referred to as i-hair sinuses or i-hair cysts, and are collectively referred to as i-hair diseases. It is characterized by the presence of hair within the i. It is a rare disease that occurs in young adults, especially in patients with heavy hair, and is more common in males. It is currently believed that the pathogenic factors are congenital and acquired. Congenital epithelial remnants or depressions are formed due to incomplete separation of the neural ectoderm from the skin ectoderm in the dorsal midline area of the spine during the process of neural tube closure in the embryo at 3-5 weeks. Acquired factors are due to the repeated twisting and rubbing of the buttocks, resulting in body hair gradually piercing the skin, forming a short tube under negative pressure, when the hair is shed, it will be sucked into the short tube and gather in the subcutaneous fat layer to become a “foreign body”. It is very easy to get infected and form sacrococcygeal sinus tracts or cysts. Luo Yong, Department of General Surgery, The Affiliated Hospital of Inner Mongolia Medical University With the in-depth understanding of i-hair disease, the reports of this disease have gradually increased in recent years. The initial typical presentation is a small sacrococcygeal sinus tract with a small amount of thick secretion on extrusion. Symptoms such as redness and swelling of the surrounding skin, pressure pain, and localized inflammatory packet fast may also be present. The authors performed surgical treatment on all 19 cases of i-hair disease in this group. Among them, one-stage excision suture was performed in 12 patients with sacrococcygeal hair-hiding sinus tracts that were not combined with obvious infections. The surgery was performed under local or epidural anesthesia, and the sinus tract was first stained with methylene blue injections along the sinus tract to facilitate intraoperative search for excision of the sinus tract wall. Then insert a probe into the opening of the sinus tract, make a shuttle incision along the direction of the probe, and incise the sinus cavity of the hidden hairs, in which more granulation tissue and multiple long and thick black hairs are seen. All the granulation scar tissue in the wall of the sinus cavity was excised, and the bottom of the sinus cavity was excised with care not to damage the presacral fascia. According to the length of the wound, 3-5 tension-reducing sutures were placed without ligation, and then interrupted sutures were placed to close the subcutaneous and superficial layer of presacral fascia, and a fine silicone drain was placed, which was connected to a negative-pressure suction device in the postoperative period. After suturing the skin, the wound was covered with a gauze roll to tighten and ligate the tension-reducing sutures. After surgery, cephalosporin sodium or lomefloxacin was put on static drip for 7d, the drain was removed in 48 hours, and the stitches were removed in 14d, and the wounds all healed in one stage. 3 cases of sacrococcygeal two sinus orifices were located in the midline of the gluteal fissure and on both sides of the fistulae, and sinus excision was performed with partial suture surgery, and the entire sinus cavity was removed, with larger range, and the skin on both sides of the wounds and the bottom of the sinus cavity were interrupted with full sutures, and a part of the middle part of the wounds was covered with Vaseline gauze, which was used for the healing of the granulation tissue growth. The granulation tissue was allowed to grow and heal. Postoperative routine anti-inflammatory treatment for 14d, and then simply change the medicine, 3d once, 25d-30d after healing. 4 cases of sacrococcygeal hidden hair cysts patients, two cases of cyst excision one stage of suture, 14d postoperative removal of stitches healed. The other two cases of cyst epidermal erythema in pediatric patients were treated with simple incision and drainage, and the wounds were healed after 20d-26d. The whole group of patients were followed up for 12-18 months, and all of them were cured without recurrence. Treatment experience: because of the repeated recurrence of sinus tract, infection can make the sinus cavity enlargement or the formation of multiple sinus tracts, so that it is difficult to one-stage resection and healing, so the sacrococcygeal i-hair disease clinically once diagnosed that should be early surgical treatment. The choice of surgery depends mainly on the degree of lesions, the presence or absence of foci of infection and other factors. The first surgery is particularly important, poorly handled may recur. For a single sinus tract, there is no peripheral redness, swelling and pressure, no abscess formation can be a one-stage excision suture. If there are multiple sinus tracts, long history of disease, recurrent episodes, and deeper sinus tracts than 7.5cm, then it should be dealt with according to the situation. If the resection range is large, Z-type flap molding or sinus tract excision partial suture surgery. When the sinus tract or cyst is in an acute inflammatory state, anti-inflammatory treatment before surgery is appropriate; or simple incision and drainage can be made, and then radical surgery after 3 months. In our group, there were 12 cases of multiple hairs in the sinus tract, and no hairs were seen in the 2 pediatric patients who had incision and drainage for secondary infection of the cyst. 5 patients who had previous incision and drainage and sinus tract scraping surgery also had no hairs, which may be related to the previous drainage and scraping surgeries to remove hairs in the lumen of the sinus tract. Pediatric sacrococcygeal i-hair cysts are rare, and two cases in our group were infants and young children 3 months and 9 months after birth, respectively, who came to the clinic for redness, swelling, and infection of the sacrococcygeal region and found the disease. ultrasound showed cystic changes in the subcutaneous tissue of the sacrococcygeal region without obvious peritoneum, and MRI showed that the cysts were located in the posterior part of the sacrococcygeal vertebrae, and were not in communication with the spinal canal. It was promptly incised and drained, and healed after anti-inflammatory and local dressing change. Because the sacrococcygeal area is close to the angle of the sacrum with little subcutaneous fat, the surface of the sacral fissure is only covered with skin and a layer of fibrous membrane, which is easy to be extruded and cause localized bedsores, and once the infection is easy to spread to the vertebral canal, it can be combined with bacterial meningitis, epidural abscess, etc. At this time, it is necessary to take the initiative to incise and drain the cyst as early as possible. At this time, it is necessary to take the initiative and cut and drain as soon as possible. When the infection is combined with intravertebral abscess, the condition progresses rapidly, with persistent high fever, significantly higher white blood cell count, redness and swelling of the skin around the sacrococcygeal sinus tract, pus flow, and even symptoms of spinal cord neurological dysfunction. In addition, in the diagnosis and treatment of pediatric patients, attention should be paid to the identification of spinal cord embolism. The latter, in addition to the clinical manifestations of i hair disease, mainly limb movement disorders, manifested as low muscle strength, reduced activity, or only thigh activity without calf activity, unable to stand and so on. Incontinence and increased frequency of bowel movements may occur. The diagnosis can be confirmed by CT or MRI.