[Health Lecture] How to treat polydactyly?

According to reports, about 200,000 to 300,000 children with congenital malformations visible to the naked eye are born in my country every year, and the incidence of neonatal birth defects is as high as 6%. As a hand and foot surgeon, I will see some children with congenital malformations of the hands in the clinic, and I have seen too many parents crying in the outpatient clinic. They should have enjoyed the joy of being a parent, but they fell into endless distress because of their children's finger deformities. Many of them even ran around for medical treatment all year round. Many parents will ask: What is polydactyly? Why does my child have extra fingers? What factors are related to this disease? How to treat it? Is it okay without surgery? How to do the surgery? How to give anesthesia? Will the child be stupid after general anesthesia! What is the best way to recover after surgery? What can I look like? Will it grow again after the operation? Will it be the same after giving birth to a second baby?

1. Overview

Polydactyly refers to the presence of more than five fingers at the distal end of a hand, which manifests as constricted fingers other than normal fingers, or as the growth of phalanges, simple soft tissue components or metacarpal bones of fingers. It is the most common congenital malformation of the hand in clinical practice, and its incidence rate is reported to range from 5 to 19 per 10,000, which is still quite high. Polydactyly can exist alone or as a manifestation of various syndromes, such as Bloom syndrome, Beckwith-Wiedemann syndrome, Holt-Oram syndrome, etc. Therefore, when polydactyly occurs, it is also necessary to check for abnormalities in other parts of the body, especially the heart, craniofacial region, and urinary system. Polydactyly can be divided into radial polydactyly, i.e., double thumb, central polydactyly and ulnar polydactyly, among which double thumb is the most common.

2. Etiology and Genetics

The occurrence of polydactyly is affected by both genetic and environmental factors . Some polydactyly is obviously hereditary and is autosomal dominant . Some are caused by interference with finger development in early pregnancy. The cause may be that the limb buds and ectodermal crowns are specially damaged in the early stage of formation, causing the original embryo to split and cause limb (finger) duplication. This is the definition in genetics, but many times parents do not have polydactyly, so why do children have it? This may be related to some special damage to the mother during pregnancy, and may be related to factors such as viral infection, drugs, radiation, pollution, etc.

3. Clinical manifestations and classification

Generally speaking, it can be divided into radial polydactyly (i.e. thumb polydactyly or thumb duplication deformity) according to the location of the multi-digit polydactyly; polydactyly occurring on the middle finger is called middle finger duplication deformity; and polydactyly occurring on the ulnar side of the little finger is called ulnar polydactyly, i.e. little finger duplication deformity . Among them, thumb polydactyly is the most common.

According to the clinical manifestations of thumb polydactyly and the bone and joint deformities, the most commonly used classification of thumb polydactyly is to refer to the thumb X-ray film and divide thumb polydactyly into 7 types according to the Wassel classification method, namely the distal phalanx type, the proximal phalanx type and the metacarpal type. Each deformity is further divided into two types according to the degree of separation of the duplicated fingers: the bifurcated type with bony connection and the compound finger type with joint connection. Together with the three-segment thumb type, there are 7 types in total (Figure 3), among which type IV is the most common, accounting for about 47%, type VII accounts for 23%, and type II accounts for 15%. This classification method is concise and in line with the pathological and anatomical laws. As shown in the figure:

IV. Treatment

Polydactyly seriously affects the appearance and function of children's hands, and can easily affect their psychological development, learning and social life, and even their future employment, work and marriage.

Surgery is the most effective way to treat polydactyly! The principle of surgery is to remove unnecessary structures and reconstruct or combine the necessary parts into a new thumb with good appearance and function. However, surgery is not a simple "one size fits all" approach. It is equally important to have a beautiful appearance and to reconstruct the finger function. Therefore, you must choose a professional and regular medical institution for surgery.

When is the right time to have surgery?

The choice of surgical timing is the key to whether secondary deformities occur after surgery for multiple thumb deformities. The timing of surgery should be based on the complexity of the deformity, the general health of the child, the safety of anesthesia, and the requirements of the parents, and follow the principle of individualization. The period from 6 months to 3 years after the baby is born is the shaping period of hand function. During this period, the ossification centers of the phalanges appear one after another, and the anatomical structure is clear, which is conducive to the doctor's operation. At the same time, the grasping function of the child's fingers has formed a control area in the cerebral cortex during this period, which is more convenient for functional exercise and recovery after surgery. For simple polydactyly, especially ulnar polydactyly, surgery can usually be performed when the child is about 6 months old; and for those with severe deformities, obvious ulnar and radial deviations, or three-segment thumb deformities that require osteotomy correction, it is also recommended to perform surgery when the child is about 6 months old. If the operation is performed too early, due to imperfect bone development, it is easy to cause long-term developmental deformities, and a second operation may be required. If the operation is performed too late, the supernumerary fingers are likely to compete for position and nutrition, resulting in poor development of healthy fingers.

About the Author

Zhang Haiyang, West Campus of Zibo Central Hospital, Hand and Foot Surgery, attending physician, master's degree student, democratic party (China Democratic League), graduated from Xinjiang Medical University in 2015, majoring in orthopedic surgery, has published two SCI papers since work, and studied in the Hand Surgery/Foot and Ankle Surgery Department of the Second Hospital of Shandong University in 2022. An excellent teacher of Binzhou Medical College, currently a member of the Science Popularization Committee of the Chinese Medical Education Association, a member of the Foot and Ankle Professional Committee of Shandong Research Hospitals, a member of the Foot and Ankle Professional Committee of Shandong Medical Engineering, and a member of the Trauma Surgery Committee of Zibo City. Main research directions: treatment of severe multiple injuries, diagnosis and treatment of diseases related to foot and ankle and congenital malformations, etc., specializes in: diagnosis and treatment of foot and ankle and congenital malformations.