Ectrodactyly is a malformation of the extremities, in which there is an absence or underdevelopment of one or more toes and hands, sometimes involving the metacarpal and metatarsal. In a typical case, the number of fingers is reduced or part of the fingers are underdeveloped, a deep cleft is revealed along the middle line of the hand or foot. With atypical cleavage, the middle components are underdeveloped or absent, the deepening of the interdigital gap is determined. Pathology is diagnosed on the basis of examination, radiography, ultrasound, CT, MRI and other imaging techniques. Treatment – operations to eliminate an external defect and increase the functionality of the segment.
Ectrodactyly is a reductive malformation of the distal extremities. It can be detected in isolation or in combination with other congenital anomalies of the limbs. It is found in 1 out of 90-150 thousand newborns. Unlike many other orthopedic defects, it has a predominantly hereditary character, often combined with certain pathologies of other organs and systems. The degree of severity of the defect varies significantly – from a slight deepening of the interdigital gap to a rough deformation by the type of claw.
In 90% of cases, pathology develops as a result of inherited mutations. Usually the 7th chromosome suffers, less often the 3rd chromosome. The anomaly is transmitted by an autosomal dominant type, combined with ectodermal dysplasia, malformations of the lacrimal and genitourinary tracts, facial cleftages. There are reports of X-linked and autosomal recessive inheritance. In other cases, the cause is the following adverse factors affecting the fetus during pregnancy:
- neoplasms of the uterus;
- endocrine disorders in the mother;
- infectious diseases of the mother;
- exposure to ionizing radiation and substances with teratogenic effects;
- disorders of placental circulation of various genesis.
Taking into account the peculiarities of the change in structure, the absence of certain segments, the presence of concomitant deformities, two variants of ectrodactyly are distinguished:
- Primary. Distal underdevelopment of segments. In mild cases, only the nail phalanges suffer. With defects of moderate severity, the nail and middle phalanges are affected. In severe cases, distal segments are absent, proximal segments are absent or underdeveloped. Concomitant soft tissue deformities are not detected.
- Secondary. The reduction of segments is characterized by the same patterns as in primary ectrodactyly. The anomaly is combined with various concomitant defects, including syndactyly, brachydactyly and clinodactyly.
Taking into account the number of fingers, mono-, di-, tri- and tertradactyly are isolated. The most common variant is didactyly with splitting of the distal segment of the limb according to the type of crustacean claw. The lesion in ectrodactyly is usually bilateral.
The malformation is detected at birth. Attention is drawn to the unusual appearance of the child’s hands or feet. Some fingers are underdeveloped or missing. Two deformed fingers with splitting of the foot or hand are often detected. The degree of limitation of the function of the affected limbs varies significantly depending on the severity of the pathology.
Ectrodactyly entails a violation of social adaptation due to the presence of a gross cosmetic defect. Children with this pathology are often neurotic, shy away from their peers, which negatively affects their psycho-emotional development. Violations of the function of the hands become the cause of disability. With ectrodactyly of the feet, there is a non-physiological load distribution when standing and walking, this leads to the development of curvature of the spine, early osteochondrosis and arthrosis of the joints of the lower extremities.
Pathology is detected by orthopedic doctors. Diagnosis is not difficult. Diagnostic studies are aimed at clarifying the possible hereditary nature of the anomaly, assessing the severity and features of the anomaly for drawing up a surgical treatment plan. During the examination, the following are carried out:
- Collection of a family history. Since ectrodactyly is often part of the symptom complex inherent in hereditary pathology, the patient or his parents find out whether there were typical cases of damage to the musculoskeletal system and other organs in the family.
- Radiography. The pictures show the absence or underdevelopment of the finger bones, sometimes the metacarpal and metatarsal bones. The technique allows you to assess the severity of changes on the part of the bone system, plan the operation.
- CT and MRI. They are carried out to clarify the results of radiography, make it possible to detail the unique features of the structure of the feet or hands on the basis of layer-by-layer study and creation of a three-dimensional model.
- Sonography. Ultrasound is performed to assess the condition and structural features of soft tissues. To study the features of the blood supply to the segment, Dopplerography or duplex examination is performed.
- Neurological research. Disorders of the development of bones and soft tissues cause individual features of the innervation of abnormal segments, which must be taken into account during surgical interventions. These features are revealed during neurological examination, electromyography and other studies.
- Genetic research. They are indicated in the presence of data on the hereditary nature of the pathology. With the probability of having a child with ectrodactyly, they are performed not only in the postnatal period, but also at the stage of intrauterine development.
Hereditary ectrodactyly is associated with a high probability of multiple congenital anomalies, therefore, if this variant of the disease is suspected, an extended examination is indicated. The patient is examined by an ophthalmologist, an otolaryngologist, a dentist. Consultations of a urologist and a gastroenterologist are appointed. The list of instrumental and laboratory tests is determined by the identified violations.
Differential diagnosis of isolated ectrodactyly is carried out with amniotic constrictions, brachydactyly, cleavage of the hand. When the hereditary nature of the disease is detected, a distinction is made between ectrodactyly-dermal dysplasia syndrome, ADULT syndrome, LMS syndrome, Rapp-Hodgkin syndrome and some others.
Pathology treatment is only surgical. The purpose of therapeutic measures is to restore the functionality of the distal segments of the limbs, eliminate or minimize a cosmetic defect. During operations on the feet, they achieve an even distribution of the load and the correct positioning of the legs while walking. When intervening on the hands, they provide the possibility of capturing objects.
Operations are usually performed in the microsurgery department, often with the participation of neurosurgeons and vascular surgeons. It is possible to use the following techniques:
- Separation of fingers with replacement of defects with skin and soft-tissue flaps.
- Transplantation of fingers from the foot to the hand.
- Arthroplasty of joints, partial excision of soft tissues that prevent movement.
- Arthroplasty of the joints of the hands.
Often combined methods are used, multi-stage interventions are performed. In the postoperative period, long-term rehabilitation is carried out, aimed at developing new motor stereotypes.
The prognosis for ectrodactyly is determined by the severity and localization of the defect. With claw-like foot defects, the possibilities of restoring the functions of support and walking are regarded as good. With anomalies of the development of the hands, the outcome is more uncertain, differs greatly in different patients, depends on the severity of violations, the timeliness and correctness of the choice of intervention tactics, the volume of rehabilitation measures.
The only way to prevent hereditary ectrodactyly, combined with other malformations, is early detection of pathology in the prenatal period and termination of pregnancy. The probability of isolated defects can be reduced by timely treatment of maternal diseases, excluding the influence of negative factors on the fetus.