About gluteal myoclonus

"Gluteal myoclonus" is a medical disease caused by the injection of the gluteal muscle in infancy, which has caused thousands of children and adolescents to suffer from lameness and even life-long disability, which is surprising and reflective. Recently, I was invited by Pingzhou Hospital in Nanhai City, Guangdong Province to visit Nanhai and Zhongshan City to investigate this disease.

Symptoms and pathogenesis of gluteus contracture

The gluteal muscles (including gluteus maximus, gluteus medius, gluteus minimus, and vastus tensor fasciae latae) are the main power muscles of the human body to maintain the stability of the pelvis and hip joints, and to maintain upright walking. When contracture of fascia or muscle occurs due to injury or infection of gluteus maximus muscle in infancy, in mild cases, both hip joints cannot be retracted internally, and it is impossible to finish stilt walking, which affects the function of running and jumping. In severe cases, when squatting, the legs are extremely abducted and externally rotated, resembling frog-shaped legs, commonly known as "frogman". In very serious cases, the passive hip flexion function completely disappears, and even urination and defecation can only be standing position, resulting in serious disability. After the contracture of the gluteal muscle, if you do not implement surgical treatment before school age, will be secondary to osteoarthritic deformities, leaving a lifelong disability.

Causes of gluteal myoclonus

Gluteal myoclonus is a disease of medical origin, which has been recognized in the medical community (in rare cases, it is congenital). Injections into the gluteal muscles are the main cause of the disease. After repeated injections, the mechanical damage of the needle to the muscle and the stimulation of chemicals cause local hemorrhage, edema to myofibrillitis, and eventually fibrosis and scarring contracture of the gluteal muscle. Although the dilution of potassium salt penicillin with benzyl alcohol can reduce the pain during intramuscular injection (benzyl alcohol has the effect of local anesthesia and antiseptic), the irritation and chemical damage to the muscle tissues are more serious, which is the main reason for the high incidence of the disease in Guangdong Province. Young children before the age of four, the gluteal muscle muscle development is poor, the muscle is slender, the absorption function and anti-stimulation ability is poor, repeated multiple intramuscular injections, either mechanical or chemical stimulation, can cause local myocyte damage or hemorrhage. Hypotonic or high concentration of drugs, resulting in changes in the local fluid environment, or toxic side effects of drugs, so that the myocytes degeneration and necrosis, the formation of fibrosis, scarring, loss of elasticity. Children in the process of growth, bone growth is normal, and contracture tissue relative growth is slow or no growth, the inevitable occurrence of hip abduction, external rotation deformity, and then secondary to osteoarticular and even lumbar spine deformity changes.

The younger the child, the more frequent the muscle injection, the concentration or dosage of the drug is unreasonable, the more necrosis of the hip muscles and fascia, and the more severe the contracture of the hip muscles. According to the statistics of Pingzhou Hospital, the favorable age is before 4 years old, of course, we can not exclude the factors of susceptible people, such as Lianzhou County, Guangdong Province, a family of 12 children in 6 sick.

The occurrence of gluteal myoclonus has a clear geographical factor. Large and medium-sized cities with standardized operating regulations are less likely to cause gluteal myoclonus. The disease occurs mainly in underdeveloped areas. For example, the authors in September 2001 in Shaanxi Huarong County, Taoxia Town, a census of more than 80 cases of patients, a mountain village in Jiangsu Province during the same period occurred more than 20 cases of patients, are muscle injection of penicillin potassium salt caused. Because gluteal myoclonus occurs gradually during the growth and development of children, without pain and other uncomfortable symptoms, early attention is not paid to the children and their families, and it is easy to delay treatment.

The Guangdong Provincial Department of Health issued a letter in July 2000 to stop using benzyl alcohol to dissolve penicillin for intramuscular injection, but new cases still occur in the region, mainly some rural doctors practicing medicine is not standardized for infants and young children's colds, fever, diarrhea and other illnesses are all line hip muscle injection. It can be seen that the main measure to prevent this disease is to regulate the medical behavior of rural doctors.

Diagnosis and treatment of gluteal myoclonus

Because children in underdeveloped rural areas are less likely to go to orthopedic departments of large hospitals for examination, and orthopedic textbooks are less likely to discuss this disease, many doctors are still unfamiliar with this disease or even don't recognize it, so that they do some unnecessary and expensive tests such as CT, MIR, etc. In the last two years, the authors have surgically treated this disease in the past two years. Among the more than 30 patients surgically treated by the authors in the past two years, a considerable number of them have been misdiagnosed or even mistreated elsewhere. If the clinician understands the characteristics of this disease, he or she can confirm the diagnosis based on the clinical symptoms alone, with almost no need for any auxiliary tests.

Examination of light children can not stilt legs, lying on their backs; the affected limb neutral hip flexion with popping; the heavier children in the knee position can not squat, the two knees apart before squatting, and both sides of the buttocks are concave, pointed buttock deformity, the heavier frog position leg squatting. In the most severe cases, the hip flexion function is completely lost, and the life function is seriously affected (all see the left figure). x-ray examination, the patient's pelvis, the femoral neck stem angle and anterior tilt angle have bony deformity changes, and even secondary to hip dislocation.

TreatmentThe contracture of the gluteal muscles, once it occurs, will not be reversed, but will only gradually worsen with age, and it is possible to release the contracture through physical therapy in mild cases. In mild cases, it is possible to release the contracture with physical therapy. If a hip abduction contracture has already occurred, surgical release is the only option. The younger the age, the less invasive the surgery is, and the surgery does not require special equipment and conditions, the better the outcome of the surgery, the more the child's gait and function can be completely normalized after the surgery, and a series of osteoarthritic complications secondary to this disease can be avoided. In the severe type over 16 years of age, symptoms and function can be significantly improved after surgery, but secondary deformities and claudication are difficult to disappear completely.

The surgical method has been relatively mature, for mild or moderate patients, a small skin incision of 3 cm in length is made posteriorly over the greater trochanter of the femur, and the contracture tissue is peeled off and exposed to be cut off in different planes and layers. The mechanism of the surgery is to cut the connection between the contractured gluteal muscle and fascia and the femur, so as to restore the flexion and adduction of the hip joint. The restoration of passive hip motion can be tested intraoperatively. A skilled orthopedic surgeon can usually perform a hip release in a few minutes or ten minutes. Since most of the disease occurs bilaterally, both lower extremities should be operated on at the same time. Hip adduction and flexion exercises should be performed early after surgery. Exercises are performed with a "one" walk similar to that of a model. The older severe type due to extensive contracture of the gluteal muscles and skin, and even secondary bony changes in the pelvis and hip joint, the surgery is very traumatic, and it is difficult to restore the appearance and function to normal after surgery.

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Gluteal myoclonus was first reported by Volederrama in 1969, and nearly 1,000 patients occurred in Taiwan in the 1970s as a result of intramuscular injections in the buttocks of infants and children. The occurrence of the disease was first reported in the late 1970s on the mainland, and the incidence has gradually increased since then, and the name of the disease has been discussed. Since the 1880s Qin Sihe has surgically treated more than 100 cases; Xi'an He Xijing has reported more than 80 cases; Yu Huiguo has reported 303 cases; and the PLA 301 Hospital has treated more than 40 cases with laparoscopic surgery in recent years.

From 1994 to 2002, more than 2,000 cases of gluteal myoclonus were treated surgically at Pingzhou Hospital. The minimum age of the patients was 4 years old, and the average age was 13.6 years old. According to the hospital's survey of primary and secondary school students in Foshan, Qingyuan, Lianzhou and other places, the incidence rate of 5.6% to 20%, of which a school of more than 400 people, that is, 80 children have the disease. Statistics confirm that the younger the age of the child's intramuscular injections and the more frequent the hip injections, the higher the chance of gluteal myoclonus occurring. By this inference, there are still a considerable number of unchecked and untreated gluteal myoclonus in Guangdong Province. What is the national prevalence? And how many adolescents with physical disabilities are caused by this disease? There is no survey yet.