Carpal tunnel syndrome
Carpal tunnel syndrome is a syndrome caused by pressure on the median nerve in the carpal tunnel due to volume reduction or pressure increase in the carpal tunnel, resulting in numbness and pain in 3 to 4 fingers on the radial side, which is more obvious at night or early in the morning, and the pain sometimes radiates to the elbow; sometimes the thumb abduction, weakness to the palm, and inflexible movement are the main manifestations.
Carpal tunnel syndrome is a clinical symptom caused by the compression and stimulation of the median nerve in the carpal tunnel. Any factor that increases or enlarges the contents of the carpal tunnel or reduces the volume of the carpal tunnel can lead to this disease.
The etiology of the disease is unknown in most patients and is mainly related to the following factors.
(1) Changes in the endocrine system (e.g., pregnancy, lactation, menopause, etc.)
(2) Fracture or injury to the wrist.
(3) occupying lesions in the carpal tunnel.
(4) Infection of the wrist.
(5) rheumatism or rheumatoid etc.
(6) Wrist strain.
Clinical manifestations include numbness and pain in the wrist, thumb, index and middle finger, abnormal sensation, weakness in the thumb, and pain on percussion of the wrist. Some patients have a history of acute trauma or chronic strain injury. The disease is mostly seen in middle-aged and elderly people, more women than men, with one or bilateral onset, and is more likely to occur in people who often engage in grasping and rubbing. The disease is usually cured by non-surgical treatment. If the non-surgical treatment is ineffective or the symptoms are aggravated, surgical treatment should be adopted, and the results are mostly good.
Clinical manifestations
1. Numbness and pain in the wrist, radial side of the palm surface of the hand, thumb, index finger, middle finger and radial side of the ring finger, which may radiate to the elbow and shoulder. The symptoms are worse at night or early in the morning; they are relieved after activity and hand shaking.
2. Sensation in the above-mentioned areas is diminished or absent. The thumb abduction, flexion and opposite palm muscles are weakened. Compression on the palmar side of the wrist may aggravate the symptoms.
3.If the disease lasts for a long time, atrophy and paralysis of the interphalangeal muscle can be seen.
4.The wrist flexion test and nerve stem percussion test (Tinel’s sign) are positive.
Diagnosis and differential diagnosis
1. Numbness and pain in the wrist and thumb, thumb and middle finger, abnormal sensation, thumb to palm restriction, and atrophy of the greater interphalangeal muscle.
2, Compression on the palmar side of the wrist aggravates the symptoms.
3.The wrist flexion test and Tinel’s sign are positive.
4.Symptoms subsided significantly after carpal tunnel closure.
5.Electromyography showed that the median nerve conduction velocity was altered.
6. No change in cervical spine x-ray.
Disease treatment Treatment principles
1.External fixation: If the symptoms are obvious, fix the wrist in mild dorsal extension position for 1-2 weeks with a plaster brace or splint.
2.Carpal tunnel closure: use 1% procaine 2ml and prednisolone 12.5mg for intracarpal tunnel injection once a week, 3-4 times.
3.Take anti-inflammatory and pain-relieving drugs.
4.Surgical treatment: If the non-surgical treatment is ineffective or the symptoms are aggravated or there is atrophy of the greater interosseous muscle, early surgical treatment should be performed. Cut the transverse carpal ligament to release the compression on the median nerve. Sometimes it is necessary to perform interfascicular release of the median nerve at the same time.
Principles of medication
1.Most of the patients are mainly treated with carpal tunnel closure, which can be supplemented with anti-inflammatory and pain-relieving drugs, but attention should be paid to the gastrointestinal reaction.
2. For some patients who need surgical treatment, postoperative antibiotics and supportive and symptomatic treatment can be applied.
(A) Pathogenesis
The carpal tunnel is a bone-fiber tube in the palm of the wrist, through which the thumb flexor and four superficial flexor tendons, four deep flexor tendons and the median nerve enter the hand, the carpal tunnel is on the palmar radial side of the wrist and is composed of the carpal bone and the transverse carpal ligament, the transverse carpal ligament is tough and the proximal edge is thickened, which is the main factor to compress the median nerve. The median nerve is superficially located in the carpal tunnel and is easily compressed by the transverse carpal ligament, resulting in injury.
The onset of carpal tunnel syndrome is associated with chronic injury and is prone to develop when the hand and wrist work is intense.
There are many causes of carpal tunnel syndrome, which can be broadly divided into three categories.
1.Local factors
(1) Factors causing reduction of carpal tunnel volume: such as Colles fracture, Smith fracture, navicular fracture and deformed healing after lunar dislocation, and acromegaly, etc.
(2) Factors that increase the content of the carpal tunnel: such as lipoma, fibroma, tendon sheath cyst, abnormal position of the muscles in the carpal tunnel (superficial flexor muscle belly too low, earthworm muscle belly too high), non-specific synovitis, hematoma.
2.Systemic factors
(1) Factors causing neurodegeneration: such as diabetes, alcoholism, infection, gout, etc.
(2) Factors that change fluid balance: such as pregnancy, oral contraceptives, long-term hemodialysis, hypothyroidism.
(3) Postural factors People who work excessively with their wrists, such as computer operators, disabled people walking with crutches, repeated flexion and extension of fingers and wrist joints, Gellman et al. found in 77 cases of paraplegic patients, 38 of them (49%) suffered from carpal tunnel syndrome.
However, it should be noted that the etiology of carpal tunnel syndrome is not clear in some of the patients who suffer from it.
(B) Pathogenesis
The carpal tunnel is a fibrous bone canal composed of the carpal sulcus and the transverse carpal ligament that bridges it. The radial side of the carpal tunnel is the navicular bone and most of the angular bones; the ulnar side is the pisiform bone and hook bone; the dorsal side is the skull, navicular bone, lunar bone and small polygonal bone; the palmar side is the transverse carpal ligament, which is attached to the pisiform bone and hook bone sulcus on the ulnar side and to the navicular tuberosity and most of the angular bone on the radial side. The transverse carpal ligament is tough, nearly trapezoidal in shape, about the size of a normal postage stamp (about 2 cm × 2 cm), 1 to 2 mm thick, and continues distally with the palmar tendon membrane and proximally with the carpal palmar ligament (forearm deep fascia), which is located at the level of the proximal carpal bone and the base of the metacarpal bone.
The carpal tunnel is slightly oval in cross section, with its apex on the radial side. 9 flexor tendons and 1 nerve (the median nerve) pass through the carpal tunnel, and the ratio of the area of the carpal tunnel to the total area of 9 flexor tendons and 1 nerve is about 3:1, thus, the area of the carpal tunnel provides some space for the activities of the carpal tunnel contents. The superficial layer is the superficial flexor tendon, which overlaps from the little finger to the index finger, and the deep layer is the deep flexor tendon, which overlaps from the radial side to the ulnar side, and they are surrounded by two tendon synovial sheaths, namely the radial synovial bursa and the ulnar synovial bursa.
The median nerve is located on the superficial surface of the superficial flexor tendon (mostly on the superficial surface of the superficial flexor tendon of the middle finger and ring finger), and its position is more constant. The median nerve is always in direct contact with the transverse carpal ligament, and this specific local anatomic relationship, combined with the fact that the transverse carpal ligament is a tough fibrous tissue with few elastic fibers, causes any cause of transverse carpal ligament degeneration to cause friction and compression of the median nerve, especially during dorsal wrist extension. The majority of the median nerve (about 95%) is divided into medial and lateral branches at the distal edge of the transverse carpal ligament, with the lateral branch sending out a return branch to innervate the thumb short extensor muscle, thumb to palmar muscle and thumb short flexor muscle (superficial head), and the terminal branch is the first finger palmar general nerve, the end of which is divided into three finger palmar intrinsic nerves, which are distributed in the skin of the radial, ulnar and radial edge of the index finger, and the intrinsic nerve to the radial edge of the index finger has branches to the first The medial branch is divided into the 2nd and 3rd common metacarpal nerves, and each of them is divided into 2 common metacarpal nerves to the proximal side of the metacarpophalangeal joint, which are distributed in the skin of the index finger, the middle finger and the opposite edge of the middle finger and the ring finger, and the 2nd common metacarpal nerve also branches to the 2nd earthworm muscle.
How should carpal tunnel syndrome be prevented?
Carpal tunnel syndrome can be caused by a variety of etiologies, most patients are caused by excessive hand and wrist activities, for these causes of patients prevention work is meaningful, its significance lies not only in the prevention before the onset, but also in the prevention of recurrence after the alleviation of symptoms.
In addition, relaxing the wrist before and after labor and fully moving the wrist joint can help prevent the occurrence of carpal tunnel syndrome.
2, pay attention to avoid washing cold water during labor, avoid cold stimulation and excessive stretching and flexing force, pay attention to local warmth.
3, for patients who have suffered from the disease after treatment, such as symptom relief, to pay attention to prevent recurrence, to avoid prolonged hand, wrist strength activities.
4.Patients with fractures and dislocations caused by trauma, such as numbness and pain in the fingers, should go to the hospital for examination and timely treatment to obtain good results.
Examination
What tests should be done for carpal tunnel syndrome? Without relevant laboratory tests, there are four main tests for this disease as follows.
1, electrophysiological examination electrophysiological examination suggests that the electromyography of the greater interosseous muscle and the median nerve conduction velocity measurement of the carpal finger have nerve damage signs, which is of some significance to the diagnosis.
2.X-ray examination X-ray plain film can understand whether there is bone and joint pathological changes in the carpal bone area.
3.Arthroscopy is a new examination method developed in recent years. Under the arthroscope, the pathological changes in the carpal tunnel can be understood, which can further clarify the diagnosis, and carpal tunnel release can also be done under the mirror.
4.CT and MRI examination of the wrist MRI and CT examination can provide useful clinical information and can be used to understand the situation inside the carpal tunnel, but they are not used as routine examination.
Complications
How should carpal tunnel syndrome be prevented? Carpal tunnel syndrome can be caused by a variety of etiologies, most patients are caused by excessive hand and wrist activities, for such causes of patients prevention is meaningful, its significance lies not only in the prevention before the onset, but also in the prevention of recurrence after the alleviation of symptoms.
In addition, relaxing the wrist before and after labor and fully moving the wrist joint can help prevent the occurrence of carpal tunnel syndrome.
2, pay attention to avoid washing cold water during labor, avoid cold stimulation and excessive stretching and flexing force, pay attention to local warmth.
3, for patients who have suffered from the disease after treatment, such as symptom relief, to pay attention to prevent recurrence, to avoid prolonged hand, wrist strength activities.
4.Patients with fractures and dislocations caused by trauma, such as numbness and pain in the fingers, should go to the hospital for examination and timely treatment to obtain good results.