Carpal Tunnel Syndrome

What is Carpal Tunnel Syndrome?

Carpal tunnel syndrome (CTS) is caused by mechanical compression of the median nerve within the carpal tunnel (front of the wrist). This compression causes local ischemia (restricted blood flow) and results in sensory and/or motor deficits in the distribution of the median nerve.

CTS is the most common nerve entrapment with a reported prevalence of 3-16% in the general population. The condition has a female to male ratio of at least 2 or 3:1. The peak incidence of CTS is adults age 45-60.

Median nerve irritation can occur from a variety of etiologies and multiple risk factors are often present. Extrinsic factors are often task-related and include prolonged wrist flexion or extension, repetitive wrist movements i.e. supermarket checker, and extended exposure to vibration or cold. Those working on an assembly line are at much higher risk for developing CTS than data entry personnel. CTS is more common in the dominant hand and symptoms on both sides are not unusual.

Intrinsic factors such as prior trauma to the arm or wrist resulting in fracture, dislocation or osteoarthritis may narrow the canal and can be a contributing factor. Fluid retention during pregnancy can be a cause of transient CTS symptoms. Imbalanced tension of the surrounding interconnected fascia can also limit median nerve mobility and is a suspected etiological mechanism for CTS. Lastly, there appears to be a genetic susceptibility that is partially explained by the fact that many of the other risk factors are inherited.

What Will Carpal Tunnel Syndrome Look and Feel Like?

Paresthesias (numbness, tingling, burning) in a median nerve distribution (palm side of thumb and/or first 2 fingers) with nocturnal awakening is present in 77.4% of cases. Hand volume has been shown to increase overnight rom 8 pm to 8 am and not surprisingly, CTS compressive symptoms often progressively increase over the same time period. Patients may have difficulty localizing symptoms and often initially erroneously complain that their “whole hand is numb”. Pain is generally centered over the carpal tunnel (front of the wrist) while paresthesias are reported more towards the tips of the fingers and into the hand. Pain may sometimes extend up to the elbow.

The palmar cutaneous branch of the median nerve innervates the palm, thus CTS symptoms that involve the palm suggest pronator teres syndrome, or at least an alternate source of nerve irritation. Approximately 12% of CTS patients have concurrent pronator teres syndrome.

CTS symptoms may begin nocturnally and progress from daytime activity-provoked to constant annoyance. Symptoms are aggravated by gripping activities, i.e. reading the paper, driving, painting.  Early on, symptoms may be relieved by “shaking the hands out”. In more severe cases, hand weakness or muscle atrophy may be present. Patients may complain of “dropping things” or clumsiness which may be more related to diminished sensory involvement as opposed to a true motor deficit. Complaints of a tight/swollen feeling, skin color changes, or hand temperature changes have also been reported and may be related to compression of other fibers within the median nerve.

Clinical evaluation may reveal tenderness to palpation over the carpal tunnel, limited wrist range of motion with likely complaints of symptoms at sustained end range flexion or extension. CTS is sometimes part of a “double crush syndrome”, wherein the median nerve is sensitized to compression within the carpal tunnel as a result of more irritation up the chain. Patients presenting with bilateral hand symptoms should be presumed to have central cord involvement until disproven by MRI.

How Do We Treat Carpal Tunnel Syndrome?

If left untreated, CTS may result in permanent neurologic damage. Various authorities, including the AAOS and the American Academy of Neurology recommend conservative management before considering surgical alternatives. Several clinical trials have demonstrated that conservative manual therapy and surgery had similar effectiveness for improving self-reported function, symptom severity, and pinch-grip force on the symptomatic hand in a group of CTS patients. Another systematic review of carpal tunnel syndrome research comparing surgical vs. non-surgical (ie, splint, steroid injection, or physical therapy) outcomes found: “No significant differences at 3 or 12 months” in terms of functional status, symptom severity, and nerve conduction outcomes. Therefore, conservative management is effective in comparison to surgery and should focus on resolving any site of neurologic insult along the entire course of the nerve.

Myofascial release may include soft tissue mobilization (STM) or instrument assisted soft tissue mobilization (IASTM) to the forearm, wrist, and hand with a particular emphasis on the pronator, wrist flexors and carpal tunnel. CTS patients often demonstrate impaired median nerve mobility within the carpal tunnel therefore techniques like median nerve “flossing” are effective in treating CTS complaints. Incorporation of cupping and/or elastic therapeutic taping have also shown to reduce pain and sensory disturbances as well. Additionally, manipulation and mobilization of cervical spine or bones of the hand have shown benefit.

Therapeutic and home stretching to be directed at tight muscles in the cervical spine, neck, forearm, and wrist as well as therapeutic exercise including chin retraction, carpal tunnel mobilization, median nerve flossing and gliding. Home instructions may also likely include selective rest to avoid repetitive wrist flexion or extension. Patients should avoid traditional push-ups and be cautious during positions of weightbearing through the hands to avoid trauma from sustained wrist flexion. Cycling will likely cause median nerve irritation and should be avoided until discussed with a medical professional.

As far as managing nocturnal symptoms, splints that hold the wrist in a neutral or slightly extended position may reduce symptoms. The use of a splint alone may be sufficient treatment for mild CTS cases, however are typically done in conjunction with other manual and exercise-based treatment.

Patients with significant motor/strength deficits may require consult for injections or surgery. Delaying surgical management in chronic cases can lead to prolonged or incomplete recovery.