congenital absence of radius
Introduction
Introduction to congenital absence of the humerus Congenital absence of the humerus, also known as paraaxial sacral hemiplegia or sacral rod-shaped hand, is a rare congenital malformation, but more common than the ulna. The onset is often bilateral, and unilateral is not uncommon. Male patients are more than females, the ratio is about 3:2. In the neonatal period, the forearm can be seen to bend to the temporal side, the thumb is turned to the inside, and the forearm is bent at 90°. basic knowledge The proportion of illness: 0.005% Susceptible people: young children Mode of infection: non-infectious Complications: hydrocephalus, cleft palate, hernia, scoliosis, anal atresia
Cause
Congenital absence of the tibia
(1) Causes of the disease
The true cause of congenital absence of the humerus remains unclear. According to Gegenbauer's theory, the upper limb consists of a trunk and four secondary rays. The humerus, the scaphoid, the majority of the horn, the first metacarpal and the thumb are the first ray. When the development of the first pair of rays is inhibited, there is a deficiency of congenital tibia, and the thumb is often absent. Recently, it is thought to be related to the inhibition of the growth of the cervical 7 nerve root or the phrenic nerve.
(two) pathogenesis
During the normal embryonic development period, after the limb buds appear next to the torso, the nerves guide the bone growth. The front end of the limb buds has a flat rounded shape, which forms a trunk and four rays, the thumb, the big fish muscle, the first metacarpal, the carpal bone and The humerus belongs to the first ray. Any factor interference causes the development of the first ray of the upper limb to be suppressed, and all of the humerus will be absent, and at the same time, the thumb, the big fish muscle and the scaphoid will be absent.
Prevention
Congenital absence of humerus
The disease is a congenital disease, there is no effective preventive measures, early diagnosis and early treatment is the key to the prevention and treatment of this disease, and at the same time should pay attention to the identification of the simple absence of the humerus, or the lack of humerus caused by other congenital malformations, in order to carry out the cause Treatment, early recovery of the child's health.
Complication
Congenital humerus lack of complications Complications hydrocephalus splitting hernia scoliosis anal atresia
This disease often coexists with other congenital malformations, such as: hydrocephalus, rabbit lips, cleft palate, rib deformity, pulmonary hypoplasia or atrophy, hernia, scoliosis or kyphosis, semi-vertebral body, anal atresia, clubfoot, Fanconi synthesis Consolidation of severe anemia.
Symptom
Congenital absence of symptoms of the humerus Common symptoms
1. This malformation can be divided into three types. Type A is dysplasia of the tibia, lack of growth at the distal end of the humerus, delayed ossification of the epiphysis, short distal humerus, the same level of styloid process and ulnar styloid process, and proximal humerus epiphysis. The relationship with the elbow joint is normal, the humerus shortens lightly, the scaphoid and the sacral bone are dysplasia, the sacral finger is small or absent, the wrist joint is partial, but it is more stable, the type B is partial humerus, and the distal end of the humerus is not Development, the proximal humerus normal to maintain a certain degree of stability of the elbow joint, humeral hypoplasia, fusion with the ulna, forming a type of ulnar and ulnar fusion, sometimes the tibia and the humeral head fusion, ulnar shortening thickening and bending, convex To the humerus, the wrist joint is unstable, the hand is skewed to the temporal side, and the C type is completely absent (Fig. 1B). This type is the most common, accounting for about 50% of the local deformity. Because the wrist has no humeral support, the forearm is sacral. The soft tissue is severely contracted, and the hand and the forearm form a 90° or more 90° or more. When the elbow flexes, the hand is even parallel to the upper arm, and the radial rays are completely absent, including the scaphoid, most of the horn, the first The metacarpal and thumb bones, such as the thumb, Often refers to a floating or hypoplasia, shortening humerus, capitellum or absence of dysplasia, delayed ossification distal humeral epiphysis.
2. There is a fiber connection between the ulnar and wrist joints, no articular cartilage coverage, dislocation of the wrist joint to the temporal side and the volar side, and soft tissue contracture of the temporal forearm. If the deformity is not treated, the deformity is more aggravated with bone growth. Hyperextension, limited flexion, fixed flexion deformity of the proximal interphalangeal joint, proximal interphalangeal joint and metacarpophalangeal joint X-ray showed normal, joint stiffness may be related to abnormality of the extensor digitorum, knuckle contraction The ulnar side is gradually reduced.
In 1/4 of the cases, the elbow joint is stiff and straight, and if the elbow joint is straight and contracted, if it cannot be corrected, it is regarded as a contraindication for wrist centering surgery.
The muscles are also affected, the sacral extensor muscle is absent or underdeveloped, fibrosis or fusion, the anterior muscle, the radial extension of the wrist, the diaphragm and the supinator muscle are often absent, the flexor hallucis longus, the thumb length is short. Extensor muscles and abductor muscles and large fish muscles are often absent, but the interosseous muscles, the sacral muscles and the small intermuscular muscles are generally not affected.
The extensor muscles of the wrist and the fingers are normal, but often fused together, the flexor digitorum superficial muscle is highly variable, can be underdeveloped, fibrotic or combined with the flexor digitorum deep muscle.
The biceps brachii lacks a long head, but the short head exists, but the abnormal point is often attached to the joint capsule or the remaining humerus or the upper iliac crest. The chest, small muscles and deltoid muscles exist, but the abnormalities are abnormal or The deltoid or diaphragm muscles are fused together.
3, nerve involvement: sacral nerve and ulnar nerve are normal, musculocutaneous god is often absent, phrenic nerve often terminates the elbow, the sacral side of the hand is dominated by the median nerve, the median nerve is larger than normal, located in the deep fascia of the forearm The median nerve is thicker than normal, located under the deep fascia of the forearm, and should be avoided during surgery.
4, vascular involvement: ulnar artery exists, often become the main blood vessels supplying the forearm and hand, the interosseous artery is well developed, the radial artery and the palmar artery are abnormal, the degree of vascular involvement is related to the temporal dysplasia, and the forearm is laterally interfrontal The arteries innervate from the ulnar artery, accompanied by the median nerve, and the radial artery is degenerated or absent.
Examine
Congenital examination of the absence of humerus
(1) Ultrasound examination:
Congenital defects of the humerus occur in the distal part of the humerus, and the muscles that innervate the wrist also contracture, resulting in shortening of the forearm, bending of the ulna to the tibia, and deformation of the wrist and handcuffs. Some scholars call it a "deformed hand." Ultrasound examination can show that the humerus is absent or significantly shorter, the forearm forearm is short and curved, and the hand is skewed and admits this specific deformity image.
(2) X-ray inspection:
Clinically, the bilateral lateral humerus and the orthotopic position of both sides of the humerus can be found. The humerus of the affected side can be found to be absent. At the same time, other bone deformities, such as the ulnar bones or the metacarpal and phalanx defects, can be found. It is skewed to the temporal side and forms a vertical shape with the ulna.
Diagnosis
Diagnosis and diagnosis of congenital sacral defect
According to clinical manifestations and X-ray examination is not difficult to diagnose.
The disease needs to be identified with some syndromes involving congenital longitudinal loss of the tibia:
1 lack of humerus - thrombocytopenia syndrome, is an autosomal recessive hereditary disease;
2 cardiovascular - limb syndrome, is an autosomal dominant hereditary disease.
