Upper and Lower Extremity Compression Nerve Syndromes
UPPER EXTREMITY COMMON COMPRESSION NEUROPATHIES
Median Nerve Compression Syndromes
Carpal Tunnel Syndrome
Carpal tunnel syndrome is the most common of the compression neuropathies. Compression neuropathy means that the nerve is compressed at one point or multiple points along its course. In carpal tunnel syndrome the nerve that is compressed is called the median nerve.
Compression of the median nerve results in pain and numbness of the wrist, the palm, the thumb and the fingers. In its typical presentation the fingers affected are the thumb, index and long fingers. Any motion that causes wrist flexion can worsen or precipitate numbness and tingling of the fingers and the palm. It is very common for patients to awaken at night because of pain, numbness and tingling. The reason is that during sleep we often flex our wrists and that causes the symptoms. The presentation can vary in different patients. In some patients it may present as wrist pain only. In some patients it may present as palm tingling or aching only. In some other patients carpal tunnel may present as tingling of the fingers only. It is critical to menton that carpal tunnel syndrome is very common in the population. It may affect in different degrees up to 10% of the population.
The actual location of the median nerve compression in carpal tunnel syndrome is the carpal tunnel or the carpal canal. The carpal tunnel is comprised or bony walls and soft tissue. The bony walls are the bones of the wrist and palm. The soft tissue is right under the palm skin and the wrist and it is called transverse carpal ligament. This thick fibrous transverse carpal ligament is typically what gets divided by surgery so that more space can get created for the median nerve.
Those professionals who use their hands in repetitive fashion a lot during the day as part of their work are more prone to carpal tunnel. Musicians are common amongst this group. Typists are also common.
Carpal tunnel syndrome is diagnosed during the physical examination. The diagnosis of carpal tunnel can be confirmed by nerve conduction velocity studies following the initial examination.
The effective treatment of carpal tunnel syndrome is by surgery. Carpal tunnel surgery can be open or endoscopic. Either operation can be equally effective.
A very thorough evaluation by a hand and upper extremity surgeon is a necessity because carpal tunnel can often co-exist with other types of compression neuropathies in the body. It is not uncommon to have compression of the ulnar nerve at the elbow or brachial plexus neuropathy at the same time. Sometimes the co-existence of other compression neuropathies can confuse the diagnosis.
- The effective therapy is to decompress the compression of the median nerve with surgery. Surgery can be open or endoscopic.
- I perform both techniques. Both techniques are discussed after thorough patient evaluation and the best is selected for each patient.
- Many other therapies are often reported and advertised in the media. Some of these therapies are steroid injections in the palm or the wrist lasers, splints worn during the day, Vitamin B6, magnets and topical creams. These treatments do not work in the long run. They are not proper long-term effective therapies.
- Splints to keep the wrist in a proper anatomic position and prevent wrist flexion are often given as first line therapy for carpal tunnel syndrome. However they do not treat the condition. They merely ameliorate the severity of the symptoms.
- Carpal tunnel syndrome and any kind of neuropathy should be operated upon earlier than later. The sooner the better. The more time a nerve gets compressed the higher the chance of incomplete recovery. Nerves are responsible for the proper function of the muscles and sensation. If nerves are compressed for a long time before correction of the compression then muscle and sensory function will not ever be complete.
- Carpal tunnel surgery is quick and may last 15-30 minutes. Patients go home the same day. I apply a soft dressing of the hand for comfort. I encourage my patients to return to their regular activities after a week.
- I can perform carpal tunnel syndrome correction and operative release under local anesthesia only if someone is afraid to go under general anesthesia.
- Recurrence of carpal tunnel is possible. In that situation the proper therapy is again surgical decompression.
Anterior Interosseous Nerve Syndrome
This compression neuropathy occurs when the median nerve gets compressed at a higher location as it comes down the forearm. Specifically the compression location of the median nerve occurs near the elbow. The compression is due to compression by fascial bands or due to certain muscles of the arm and forearm.
This compression neuropathy of the median nerve produces primarily a motor deficit as opposed to a sensory deficit. Specifically it produces weakness of the flexor digitorum longus of the index and long fingers and also weakness of the profundus muscle. Weakness of the flexor digitorum profundus of the index and long fingers means weakened ability to flex those fingers. The typical presentation is the inability to flex the terminal phalanges of the thumb, index, and long fingers. Paralysis of the pronator quadratus is also seen.
- The proper therapy is surgical decompression. Specifically the hand surgeon identifies the area of compression and surgically divides the compressive bands. This frees the median nerve and the weakness is improved.
Entrapment and compression of the median nerve in the forearm can lead to pronator syndrome alone. Usually the patient presents with an 8 -24 month history of forearm weakness, aching and pain. The pain and aching are non-localized. When forearm pronation is resisted during the physical examination the pain is reproduced. Forearm pronation means to rotate the forearm and wrist counterclockwise.
- The proper effective therapy is by surgical decompression of the constrictions.
RADIAL NERVE SYNDROMES
Superficial Radial Nerve Entrapment
This syndrome is caused by compression along the course of the radial nerve at the lower half of the dorsum of the forearm, wrist and hand. Compression bands, tight gloves, a tight cast are usual causes of this compression. There is no motor deficit with this type and once the compression is relieved everything returns to normal.
Important: de Quervain’s tenosynovitis can often by mistaken for radial sensory nerve compression. A proper history, physical examination and evaluation of the patient by a hand surgeon will help to clarify the diagnosis.
Posterior Interosseous Nerve Syndrome
This syndrome presents itself as a lack of extension of one or more digits of the hand. In a more aggressive presentation there is complete inability of extension and none of the muscles supplied by the radial nerve are functioning. The patient cannot extent the thumb, long, index, ring and little fingers. There is no sensory deficit with this type of syndrome.
- Therapy is by surgical decompression. This syndrome can be often confused as lateral epicondylitis, or resistant tennis elbow.
Important: Sometimes radial tunnel syndrome and tennis elbow can exist at the same time. Also sometimes one may confuse tennis elbow for radial tunnel syndrome. A proper thorough evaluation is critical.
ULNAR NERVE COMPRESSION SYNDROMES
Guyon’s Tunnel Syndrome
The distal part of the ulnar nerve can be compressed as it enters the wrist by the hook of the hamate bone, the pissiform bone or the Guyon canal itself. A pure motor, pure sensory or a combination of both can clinically manifest.
- Therapy is by surgical decompression.
Cubital Tunnel Syndrome
The ulnar nerve can be compressed at the level of the elbow. A combined motor and sensory deficit occurs to people. This is the second most common compression neuropathy that I have seen after carpal tunnel syndrome.
- Surgical decompression at the level of the elbow. Sometime transposition of the ulnar nerve may be required.
MUSCULOCUTANEOUS NERVE ENRAPEMENT
Dysfunction of the musculocutaneous nerve can lead to weakness or paralysis of the bicepts muscle and the brachialis muscle. A sensory deficit along the lateral aspect of the forearm can be also present.
- Therapy is by surgical exploration of the course of the nerve and decompression.
This was first described in bowlers and baseball batters. Pain of the thumb and numbness is seen. Sometimes a mass of the base of the thumb can be palpated.
This syndrome is thought to be caused by repetitive external compression. It is an overuse syndrome.
- First line therapy is conservative. It consists of rest, anti inflammatory agents, steroid injections and splinting.
- If those measures do not work then surgical exploration and decompression is due.
THORACIC OUTLET SYNDROME
This syndrome results from compression of the nerves as they come out from the cervical spine and get compressed by the scalene muscles, and the first rib. Other areas of compression may occur. Many clinical presentations may present.
This syndrome results to brachial plexus neuropathy. There are many symptoms due to involvement of compression of the median, radial, musculocutaneous and ulnar nerve distributions.
- Surgical exploration, resection of neuromas in continuity, nerve grafting, nerve transfer and surgical decompression are the techniques used to treat this pathologic entity. It is essentially a brachial plexus reconstruction.
LOWER EXTREMITY COMMON COMPRESSION NEUROPATHIES
Common Peroneal Nerve
This nerve is relatively fixed at the lateral side of the fibula. In simple terms it is found in the lower aspect of the lateral aspect of the knee and upper leg. Due to its location very close to the skin and right over the bones it can be easily injured and compressed. This is another common injury I see in athletes.
Injury to the common peroneal nerve at the fibular head gives the feeling of the leg “giving out”. Why is that?
The muscles that are innervated (get their motion by this nerve) by the common peroneal nerve control ankle exntension and eversion (moving the ankle outward). Weakness in these functions gives the feeling of loss of control and giving out of the foot.
The common peroneal nerve can be injured often by an ankle sprain. This is a frequent condition. An ankle sprain can cause traction of the common peroneal nerve. This reaction can injure the nerve.
- At first can be conservative.
- If no progress is seen within a reasonable window of time then surgical exploration and repair of the nerve is needed.
This is a syndrome described by Morton in 1875 and a well-recognized condition caused by compression to the nerve. The nerve that gets compressed is the common plantar digital nerve.
- Can range from excision of the nerve that is diseased to division of the intermetacarpal ligament that causes the chronic compression.
Lateral Femoral Cutaneous Nerve Compression /Injury
This is another often-unrecognized entity. This condition is also referred to as “meralgia paresthetica and it is caused by injury to the lateral cutaneous femoral nerve.
The injury to the lateral cutaneous femoral nerve can be caused by conditions such as prior hernia repair, prior hysterectomy surgery, lower abdominal surgeries in general, diabetes, wearing abdominal girdle and corsets.
- Surgical exploration and release of the compressed nerve and nerve repair.