The median nerve runs in the carpal tunnel along with 9 other tendons. There is a limited amount of room in the tunnel. If the tissues around the tendons (called tenosynovium) become inflamed or thickened, this results in pressure on the median nerve. Pressure on a nerve that provides sensation and motor function can lead to numbness, tingling but also weakness. This condition is usually caused by a combination of factors. Genetics play a role in leading to anatomical variations of the carpal tunnel’s size. Also, certain inflammatory and metabolic conditions can predispose patients to CTS, e.g. autoimmune inflammatory joint conditions such as rheumatoid arthritis.

CTS is a progressive condition that often worsens over time. The initial symptoms include numbness and tingling in the fingertips of the thumb, index, middle and ring finger. Nighttime symptoms (tingling and/or pain) are particularly common, and can wake patients up. As the condition progresses, atrophy (“thinning”) of the thumb muscles may occur. The numbness and weakness can become constant. Dropping objects is also commonly reported by patients as a result. Not infrequently, the pain radiates up the patient’s arm.

The patient's history is critical in making the diagnosis, followed by a physical exam that includes a number of maneuvers such as the Tinel and Phalen tests. Electromyography (EMG, also called “nerve test”) aids in further confirming the condition and locating the site of nerve compression. Dr. Sammy also routinely uses the ultrasound to diagnose the condition. CTS can be treated with a variety of options, depending on its severity.

Nonoperative measures include night splinting, hand therapy, as well as antiinflammatories. The next step in treatment can involve a corticosteroid injection into the carpal tunnel. Surgical release is often considered, depending on the severity of the compression. The procedure involves dividing the transverse carpal ligament to increase room in the carpal canal and relieve pressure on the median nerve. Dr. Sammy performs both open and endoscopic releases, depending on the patient and their individual needs.

Open Carpal Tunnel Release
The open release requires making a short incision in the palm over the carpal tunnel. Through this approach, the median nerve is released with direct visualization of the nerve. The incision is closed with dissolvable stitches. The hand is bandaged leaving the thumb and fingers free. The bandage stays on for 7 days. Immediate movement of the fingers is encouraged to help minimize swelling. Light use of the hand is allowed at 2 weeks. Heavier use at 4 weeks.

Endoscopic Carpal Tunnel Release
This is a minimally-invasive procedure that involves making a small incision along the forearm at the wrist level and advancing a camera into the carpal tunnel. The ligament is released using a special camera-mounted device. The recovery is shorter than that of the traditional open carpal tunnel release. Dissolvable sutures are used. The hand can be used immediately for light activities. Heavier activities after 2 weeks.

This illustration reveals the open versus the endoscopic approach. Although it may appear as though the endoscopic release is the best solution, this is something that Dr. Dowlatshahi will go over with you during the consultation.

The CPN can be compressed for several reasons. Sometimes it occurs without trauma, but more often, there is a history of significant leg swelling and trauma or prior surgery that leads to thickening of fascia in this area that can impinge on the CPN.

The result of CPN compression is numbness, tingling, weakness (as in foot drop), and pain. Infrequently, all these symptoms occur at the same time. More often, we see a combination of a few of these symptoms, which makes diagnosis difficult.

Nerve testing as in EMG’s can be helpful but not always. A dedicated MRI called MR neurography can be obtained. Alternatively, a high frequency ultrasound of the nerve can be more helpful in identifying more subtle changes in the nerve.

One specific circumstance which is almost an entity in itself is an acute CPN compression from a ganglion originating from the proximal tib-fib joint. This can lead to tearing and sudden pain in the nerve, often with weakness. An MRI usually shows the culprit and allows for an early diagnosis.

The causes vary and can range from direct repetitive pressure to the area in the groin from tight clothing or a tool belt, weight fluctuation and direct trauma to the area. Diabetics can develop this nerve compression, similar to other compressions that are common in this patient population such as carpal tunnel and tarsal tunnel syndrome.

Pain and/or numbness and tingling in the anterolateral thigh. The site of compression is usually in the groin area where the inguinal ligament is located. This area can be point tender.

The diagnosis is made largely clinically based on history and a thorough physical exam, although an MRI or high frequency ultrasound can be very helpful in making an accurate diagnosis. Diagnostic injections can be helpful in confirming the diagnosis, but even when steroids are administered, the effect of the injection will often wear off after several months. Occasionally, physical therapy can be helpful.

Since there are several sites of potential compression, the causes vary. Abnormal attachments of the triceps muscle (Arcade of Struthers) can compress the nerve above the elbow. Tumors such as lipomas or ganglion cysts aren’t common but can compress the nerve near the elbow. Most often, fascial bands at the elbow are the cause of the compression (ligament of Osborne). On occasion, within the flexor-pronator mass there can be a fascial layer that can compress the ulnar nerve. In some cases, the ulnar nerve can be unstable and subluxate (dislocate/slide) during elbow flexion and this can lead to compression.

Numbness and tingling in the ring and small fingers are commonly reported. Pain may or may not be present and often runs along the course of the ulnar nerve at the forearm. Weakness of the ulnar innervated muscles can lead to significant hand deformity and greatly affect hand function. In its most advanced form it can lead to an ulnar claw hand.

The history and physical exam are critical. Xrays can help determine if there is any bony abnormality at the elbow. An MRI of the ulnar nerve can be helpful in cases of prior surgery on the nerve or the nearby elbow joint and its ligaments. Also in cases of recent trauma. SInce the ulnar nerve is rather superficial, ultrasound using a high frequency probe can aid in the diagnosis. EMG and NCS (nerve testing) can help ascertain the site of compression and also determine its severity, although it can sometimes be normal.

Compressive fascial bands or crossing vessel branches can lead to compression of the femoral nerve. Other causes are space occupying lesions such as prominent lymph nodes or ganglion cysts, bursitis. A separate category consists of cases of iatrogenic injury, such as during vascular intervention, hernia repairs, hip replacements where one of the components can get dislodged, or cement can extrude around the nerve.

Pain and/or weakness, depending on the severity of the compression and the portion of the nerve that is affected.

Making an accurate diagnosis can be difficult and requires a thorough physical examination, an EMG, and more likely a high-frequency or ultra-high-frequency ultrasound to look more carefully at the nerve. MRI neurography can also be helpful in assessing nearby structures but is only performed in certain centers.

Trauma and cancer are the most common causes of a high ulnar nerve palsy/injury. Less commonly, it can also be seen as an iatrogenic complication during another surgical procedure, such as lipoma removal, placement or removal of implanted contraceptive devices, cubital tunnel release, and others.

Depending on the severity of the ulnar nerve involvement, there can be numbness, tingling, weakness in the affected hand. Muscles can atrophy, giving rise to what is called an “ulnar claw hand” which has a characteristic appearance.

The physical examination is most important to identify the extent of sensory and motor involvement and help localize the site of the ulnar nerve lesion. Ultrasound and MRI are additional diagnostic modalities that help characterize the anatomy in greater detail. Neurophysiologic testing is an invaluable tool to help identify and characterize the location and extent of the nerve lesion, and is a good tool for longitudinal followup to monitor the recovery. Typically this is obtained immediately after the lesion, and in 3 month intervals after that.

Often the cause is unclear. Some tumors are connected to known genetic syndromes, such as neurofibromatosis (type 1 and 2) and schwannomatosis. In these conditions, tumors develop on or adjacent to nerves in any part of the body. These tumors are not infrequently multiple and can lead to symptoms spanning from painful lumps to weakness, numbness and tingling. In other cases, the tumor may be due to a malfunctioning gene. A history of radiation can also increase the risk of developing a peripheral nerve tumor. More often these tumors are benign, but in certain cases, they can be malignant.

Symptoms can vary from a painless lump to focal neurologic deficits, numbness, tingling, weakness in the affected nerve. Pain can occur, and the tumor itself can be tender to touch. They often continue to grow over time.

The diagnosis is often made with cross sectional imaging such as MRI or ultrasound. The location is critical when deciding how to proceed in terms of treatment.

In this form of median nerve compression, the nerve is compressed at the proximal to mid-forearm by several structures, most often the pronator teres, but there can also be other compression sites such as the superficial flexor tendon origin called sublimis arch, and aberrant fascial bands or vascular leashes.

In contrast to carpal tunnel syndrome, more advanced cases of median nerve compression at the forearm can present with numbness and tingling in the distribution of the palmar cutaneous nerve. This is the classic differentiation of carpal tunnel syndrome from the less common median nerve compression at the forearm. The patient may also have pronounced pain in the forearm along the course of the median nerve. A tinel sign can be present.

The patient's history is critical in making the diagnosis, followed by a physical exam that includes a number of so-called provocative maneuvers such as the Tinel, Phalen, and carpal compression test, resisted forearm pronation and passive forearm supination. Sensory examination in the distribution of the palmar cutaneous nerve is critical. Electromyography (EMG, also called “nerve test”) aids in further confirming and locating the site of nerve compression. In terms of imaging studies, both MRI and ultrasound are helpful modalities, in particular the ultrasound since this can delineate any component of dynamic compression.

Depending on the severity of symptoms and the results of electrophysiologic studies, a customized treatment is often required which can range from physical or occupational therapy to surgical decompression.

Patient that underwent an endoscopic carpal tunnel release with persistence of symptoms. We performed an open release (patient incidentally had a bifid median nerve at the carpal tunnel). The blue marking on the forearm outlines the planned incision to access the median nerve at the pronator tunnel. The incision we made ended up being shorter than the initial marking.

The SPN is most often compressed at the point where it exits the fascia at approximately 10-15 cm from the ankle joint. Thickening of the fascia is a known cause of this compression and can happen after trauma, in cases of exertional compartment syndrome, but also when the patient has experienced bouts of swelling and edema that can occur after knee or ankle operations.

The result of SPN compression is most often pain that is located along the course of the nerve. The exit point through fascia at approximately 10 cm from the ankle is often point tender. Numbness and tingling in the distribution of the nerve can also be present.

Nerve testing (EMG) is often not helpful / non-diagnostic. The physical examination is the mainstay of diagnosis.. A dedicated MRI called MR neurography can be obtained. Alternatively, a high frequency ultrasound of the nerve can be more helpful in identifying more subtle changes in the nerve as it exits the fascia. If the patient presents with pain, a diagnostic local anesthetic injection performed in the office under ultrasound guidance can provide helpful prognostic information.

Compression of the tibial nerve can be due to inflammation, tumors, tight fascial bands, abnormally large muscles that lead to dynamic compression of the nerve, and sometimes due to changes in the nerve itself than can thicken and become pinched when it dives underneath various structures, most commonly fascial bands that occur everywhere in the body.

Patients with tibial nerve compression will often experience pain, numbness and tingling. Depending on the site of the compression, weakness may be present too. Lack of sensation in the feet can be problematic since it can lead to unrecognized ulcers that can become quite large and become limb-threatening.

The diagnosis is often clinical, based on the history and physical examination. Nerve tests are often obtained but can be normal, especially in dynamic compressions. MRI and ultrasound can be helpful in visualizing the nerve and its compression, but can also identify muscles that are undergoing denervation changes from lack of normal nerve electrical signals into the muscle. Diagnostic injections can be considered.

One particular challenge is differentiating tibial nerve compression from exertional compartment syndrome and popliteal artery entrapment syndrome. As a matter of fact, these conditions can be present at the same time and require specialized testing such as measurement of exertional compartment pressures, and dynamic ultrasound or MRI scan.

Treatment:

The treatment is customized to the site of compression, its cause and severity. Physical therapy to promote nerve gliding can be helpful. Gait analysis and retraining with a focused physical therapy regimen can help in high level athletes. Botulinum toxin injections can be considered if the compression is dynamic. Surgical release is recommended for more severe cases and does not involve cutting the nerve like some patients think, but actually involves releasing it from the surrounding structures so that it can recover. Depending on the severity of the compression, there may be abnormal changes in the nerve fibers themselves. These take a lot longer to recover, possibly years. This is the case with any severe nerve compression.

Any injury, such as a sharp transection, crush injury, radiation, thermal injury/burn, frost bite, cancer, stretching can lead to neuroma formation. Even inadvertent and excessive retraction during surgery can lead to nerve injury.

Pain, numbness, tingling and possibly weakness can result if the nerve has a motor component that powers a muscle or an entire muscle group. The type of pain caused by a nerve injury is often called “neuropathic pain”.

The history and physical examination are the most important steps in making a diagnosis. Additional modalities such as MRI neurography and ultrasound can be helpful in diagnosing a nerve injury. Indirect methods include Electromyography (EMG) and Nerve Conduction Studies (NCS).