Hemimelia is a birth defect characterized by the absence of all or part of the distal part of the lower or upper limb. A person suffering from hemimelia appears to have part of a limb cut off, which is why the defect is sometimes called congenital amputation of the limbs. What are the causes and symptoms of hemimelia? How is her treatment going?

Hemimelia( hemi- + gr.mélos'limb') is very rarecongenital defect , which is characterized by the unilateral or bilateral absence of all or part of the distal part of the lower or upper limb, i.e. the lower leg and forearm. There are fourtypes of hemimelia :

  • fibular hemimelia - congenital lack of fibula;
  • tibial hemimelia - congenital lack of the tibia;
  • radial hemimelia - congenital lack of a radius bone;
  • ulnar hemimelia - congenital lack of ulna;

Hemimelia may be an independent (isolated) defect. However, it often coexists with other congenital abnormalities, such as, for example, fused fingers (also known as hyperplasia, syndactyly), extra fingers (polydactyly), lobster hand / foot (ectrodactyly), congenital valgus foot, Fanconi anemia or Sprengel's disease. It can also be one of the components of the syndromes of birth defects. For example, the congenital absence of a radius is part of i.a. TAR syndrome (thrombocytopenia and radial aplasia syndrome).

Hemimelia - causes and risk factors

A spontaneous gene mutation or a disturbance in embryogenesis may lead to the development of hemimelia. The defect may also be inherited.

There are also known teratogenic (fetal malformation) factors that may increase the risk of hemimelia. These are x-rays, viral infections during pregnancy, and medications. For example, exposure of the fetus to thalidomide (in the 1960s it was a drug intended to prevent morning sickness in pregnant women) during the first trimester of pregnancy is the best known factor that can lead to a congenital radius deficiency.

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Hemimelia - symptoms

1. Fibular hemimelia - congenital lack of fibula

There are no fibula, ankle and heel bones in this defect. In addition, the thigh may be slightly shortened and the tibia may bend. The foot may be slightly crooked.

2. Tibial hemimelia - congenital lack of tibia

The limb shortening is characteristic, and the foot is turned to the extreme outside in relation to its long axis (foot supination). In addition, the knee joint (if it develops at all) in 90 percent. cases is unstable. Besides, the fibula is axially offset from the femur, it can also be deformed or normal.

3. Radial hemimelia - congenital lack of radius

Congenital absence of a radius is characterized by a shortening of the forearm - as a consequence, the hands are located right next to the elbows. In addition, the wrist is displaced in relation to the distal end of the ulna. Hypoplasia of the thumb is always present in this defect, and it occurs in various degrees of severity.

4. Ulnar hemimelia - congenital lack of ulna

The forearm is short, slightly bent towards the elbow, the elbow is flexed.

Hemimelia - treatment

In Poland, in the case of congenital lack of tibia and fibula bones, only amputation and further prosthesis of the limb are possible. However, Dr. Dror Paley, an orthopedist at The Paley Advanced Limb Lengthening Institute at St. Mary's Medical Center (West Palm Beach, Florida, USA) treats children with this defect using a special apparatus (spacial super frame - or external fixator) along with the reconstruction of joints and muscles (leg straightening, bone extension and construction of non-existent joints). It is important that the operation is performed as soon as possible, preferably between 18 and 24 months of age. Unfortunately, the operation costs are very high and amount to over PLN 1 million.

In the case of a congenital lack of a radius and ulna bone, the operation involves installing an apparatus in the skeletal system for straightening and stretching the wrist and forearm.

Category:

Genetic diseases