Carpal tunnel syndrome

OUTLINE

Define

Ống cổ tay là một khoang kín có dây thần kinh giữa và 9 gân gấp đi qua. Thành ống cổ tay cứng, được tạo nên từ xương cổ tay phía sau và phía trước bởi dây chằng ngang ống cổ tay khá dày. Thể tích của ống cổ tay chỉ vừa đủ chứa các thành phần nằm bên trong nó nên chỉ cần sự thu hẹp của ống cổ tay hoặc tăng thêm một phần nào đó trong ống cổ tay sẽ tăng áp lực trong ống cổ tay.

Carpal tunnel syndrome is a disease that compresses the median nerve in the carpal tunnel causing paresthesia, pain, numbness, and areas innervated by the median nerve. The pathophysiology of the disease is not well understood, but it is thought to be caused by compression of the median nerve in the carpal tunnel.

Reason

• The exact cause of the disease is unknown.
• Bệnh được xem gây ra bởi sự kết hợp của các yếu tố di truyền và môi trường. Một số các yếu tố ảnh hưởng bao gồm: bệnh tiểu đường, béo phì, mang thai, suy giáp, và công việc lao động nặng hoặc làm việc với các công cụ rung. Các rối loạn khác như viêm bao hoạt dịch và viêm gân có liên quan đến chuyển động lặp đi lặp lại thực hiện trong quá trình làm việc bình thường hoặc các hoạt động khác.

1. Increased capacity in the wrist, possibly due to

• Phù hoặc dày của bao hoạt dịch gân gấp như: viêm bao gân gấp (viêm thấp, chấn thương, lao,…) u sụn.
• Edema due to trauma, infection, metabolic disorder, etc.
• Injury in the space: lymph nodes, forming bone tumor, abnormal bulges inside or outside the muscle (worm muscle II, superficial flexion II, deep palmar).
• Tophy of gout, calcium deposition,…
• Hemophilia, leukemia.

2. Reducing the size of the carpal tunnel in the body is

• Inflammation of the bone joints, semilunar dislocation, Colles fracture, etc.
• Wrist fracture
• Fracture of the lower end of the radial bone, the bone is displaced anteriorly, or motionless Wrist posture can cause compression of the median nerve
• Direct pressure from crutches or canes
• The choroid holds the flexor tendon due to: powdery degeneration, acromegaly
• Congenital stenosis of the cervical canal

Classify

There is no specific classification, but according to Acta Neurologica Scandinavica. Carpal tunnel syndrome can be divided into five categories:

table 27.1. Classification of carpal tunnel syndrome

ASSESSMENT OF PATIENTS

Medical history

Tê tay là dấu hiệu chủ yếu đầu tiên, tê nhiều hay ít tùy theo mức độ chèn ép trên thần kinh giữa. Bệnh nhân bị giảm cảm giác ở mặt lòng các ngón tay cái, trỏ và giữa. Lúc đầu chỉ tê một lúc vào buổi sáng sau khi thức dậy, đẩy các khối nặng hay lái xe gắn máy rồi sau đó tê tay liên tục suốt ngày, kèm theo cảm giác tê tay là cảm giác kim châm nhè nhẹ ở đầu các ngón tay. Nếu không được điều trị, bệnh nhân sẽ mất dần cảm giác tiếp xúc và nhận biết các vật thể cầm nắm đến mức làm rơi muỗng, đũa khi ăn.

The thumb is gradually weakened due to reduced movement of the maggot muscle group in the counter-finger movements, but in the early stages, the patient does not notice it, and in the later stages, the humerus is clearly atrophied.

Clinical examination

• Look for Tinel's sign on the median nerve at the wrist: taping the median nerve is positive if the patient feels electrical currents in the median nerve supply (spinning or pain), this test is positive. In 15 – 30% cases, negative results cannot rule out carpal tunnel syndrome.

• Find the feeling of vibration with frequency 256, 128, 32 Hz using tuning fork. The disease is more severe if the sensation is reduced with low frequency.
• Look for signs of decreased ability to distinguish two points on the same lobe.
• Look for Phallen's sign: let the patient flex the wrist for 30-60 seconds causing pain or numbness in the neck This test is positive in 70-80% cases.

Subclinical

• Conduct clinical trials including:

+ Capture X-ray: cervical spine four postures

+ Electromyography EMG (electromyography):

• It is very necessary for patients with suspected carpal tunnel syndrome, it is both valuable in diagnosis, legal, surgical indication and postoperative follow-up.
• Normal motor conduction < 4.4 milliseconds
  • 5 milliseconds: moderate nerve damage
  • 6 milliseconds: surgical indication is required
• Sensory conduction is slow, and when sensory action potentials are abundant, the indication is more delicate than motor transmission.

Upper limit of normal conduction # 4 milliseconds. Lower limit of normal potential # 8 milliseconds.

DIAGNOSE

Defined criteria: clinical examination + electromyography. X-rays of the cervical spine are necessary to rule out carpal tunnel syndrome, where cervical nerve roots are compressed due to foramen stenosis.

Diagnose the cause: usually not needed because the specific cause of carpal tunnel syndrome is unknown.

Differential diagnosis

There are diseases, patients also have symptoms similar to carpal tunnel syndrome:

• Spine diseases: cervical spondylosis, herniated discs, vertebral body tumors, etc.
• Peripheral neuropathy: peripheral neuritis (due to history of diabetes and elevated blood sugar)
• Arthritis Fingers (pain with joint movement)
• Rotator cuff tendon bursitis (pain near base of thumb)
• Medial nerve compression at the elbow (weak wrist flexion)
• Hypothyroidism
• Carpal synovial cyst (with tumor of the base of toe I).

TREATMENT

Purpose

Restoring movement and feeling of damaged limbs, in order to bring the highest efficiency to help patients soon recover daily activities with optimal quality of life.

Rule 

• Once carpal tunnel syndrome has been identified, it should be treated immediately because if left for too long, the damage to the median nerve is difficult to recover.
• Depending on the time of the injury, there is an appropriate treatment method
• No further damage.

Specific treatment

In the early stages, the disease is mild, only need to wear a wrist brace at night for 2 months, the drug only supports the natural recovery including group B vitamins, ATP and calcium.

In the later stages, surgery is required. If the disease is not long, it is enough to open the carpal tunnel, cut the ring ligament and release the median nerve, but if the disease has been around for a long time, especially if there has been atrophy of the female muscles, the nerve sheath is fibrous, it is necessary to peel and cut the outer envelope. The classic incision on the front of the wrist will create an invisible scar as it heals

1. Indications for surgery

• Symptoms do not reduce with conservative treatment, splints 2-4 weeks, restricts movement for one month
• Pain several times a day
• Partial atrophy of the gynaecomastia
• Suspected tumor compressing the wrist: lipoma or neuromas
• Electromyography severity.

2. Surgical technique

Local anesthetic, garrot. There are two methods of surgery:

Open surgery

- The incision: depends on the surgeon. Usually one of the following three incisions is used:

+ Classic skin incision: following the humeral fold down to the wrist crease, bend the ulnar angle to avoid damaging the palmar branch of the median nerve that distributes the palmar surface, this branch is usually located between the palmar long arm and the neck flexion. hand crank, if damage to the branch will reduce the sensation of the mound.

+ Skin incision L: skin incision parallel to the crease of the mound (usually the line between the 3rd and 4th fingers) to the wrist crease, making a horizontal incision of 1 cm inclined the cylinder.

+ The incision across the wrist crease is 1-2 cm depending on the surgeon.

When examining the median nerve, if there is stenosis or surrounding fibrous tissue, the fibrous tissue should be dissected. In most cases, decompression of the median nerve by transverse ligament ablation is sufficient to improve microcirculation. However, in cases of fibrosis, the inner nerve fibers are still compressed in the fiber bundles. Nerve sheath dissection produces a significant injury to the nerve fiber such as microbleeding, edema, scarring, and microcirculation changes.

In addition, it is very easy to cut into the structure that they form bridges between adjacent fiber bundles. Curis and Everomann (1973) recommend sheath dissection when patients have persistent sensory loss and muscle atrophy. According to the author F. Marin. Braun It is recommended that when there is atrophy of the gynaecomastia, examine the nerve division with a magnifying glass.

Endoscopic: Make a small incision to insert the endoscope to view the transverse ligament and cut.

3. Complications after surgery

• Injury caused by the physician injuring the median nerve, cutting into the palmar branch or the recurrent branch of the female tissue
• Carpal tunnel decompression is not completely prone to recurrence
• Surgical wound complications

+ Infections

+ Open incision

+ Incision pain due to the dermal branch being attached to the surgical scar, painful keloids, and shrinkage scars from the incisions perpendicular to the wrist crease.

• Weakness in handling heavy objects
• Stiffness in fingers and wrists
• Burning sympathetic dystrophy due to frequent effects from minor trauma of the median nerve
• Recurrent carpal tunnel syndrome due to perineural fibrosis and synovial hyperplasia
• The flexor tendon loses its fulcrum like the bowstring.

FOLLOW-UP EXAMINATION

• Days 1 and 2: The patient is hospitalized with his arms hanging high until the pain is gone and the edema is reduced, and begins to exercise the fingers.
• Weeks 1 and 2: Wrist splint 2 weeks. Should not be left free, tired arms can be removed several times a day and exercise shoulder and elbow exercises.
• Weeks 3 and 4: place a firm bandage on the wrist, allowing only light movements.
• Weeks 5 and 8: Can do light work without lifting heavy objects or repetitive tasks for up to 3 months.