Splinting for Carpal Tunnel Syndrome: It’s Not a One-Size-Fits-All Solution

Carpal tunnel syndrome (CTS) is a common condition, affecting approximately two out of every 100 individuals in the United States.¹ Patients with CTS report pain, numbness, and tingling in the median nerve distribution of the hand and often attempt to self-treat their condition.

The Problem with Over-the-Counter Splints

Patients can find a variety of retail remedies readily available due to the high incidence rate of CTS. Those affected may also seek intervention suggestions from family, friends, and the internet. The effectiveness of orthoses or splints for treating CTS has been demonstrated in several studies, including a systematic review by Page, et al.²

Eventually, patients may be referred to a therapist for treatment and may report to the clinician that they have been wearing an orthosis without relief of their symptoms. The treating therapist must recognize that not all orthoses are created equal. Some may even cause more harm than good.

Fitting a Patient for Orthosis

Proper positioning of the wrist is crucial in decreasing pressure on the median nerve and reducing symptoms. A study by Gelberman, et al.,³ measured intracarpal canal pressures on the median nerve with a wick catheter. Pressure to the median nerve increased when the wrist was placed in flexion or extension, but pressure was low in the neutral wrist position.

Some prefabricated orthoses place the wrist in extension, actually increasing pressure on the median nerve. The therapist may need to modify the patient’s prefabricated orthosis by adjusting the metal stays to place the wrist in a neutral position.

Additional pointers to keep in mind when guiding a patient in the use of an orthosis include:

• Pressure from the orthosis at the wrist near the superficial branch of the radial nerve causes additional numbness and tingling to the dorsal/radial aspect of the hand.
• Failure to limit digit motion with the orthosis can increase pressure in the CT by virtue of the lumbricals descending into the tunnel during digit flexion. In some cases, the digits need to be included in the orthosis to prevent 75 percent of full digit flexion and to avoid invasion of the proximal reaches of the lumbricals into the carpal tunnel.⁴ This is important when an individual sleeps with the digits in flexion and symptoms are persistent (see photo below).

• Increasing the wearing time may also be helpful, according to studies by Walker, et al.,⁵ and Hall, et al.⁶ Some patients report reduced symptoms when wearing the orthosis while sleeping, but others may require additional wear during waking hours.

The application of an orthosis for CTS, whether custom fit or prefabricated, needs to consider fit, wearing schedule, and the neutral wrist position to be effective in decreasing symptoms.

There are many interventions other than orthoses for conservative management of CTS. For more information on this topic, my MedBridge course Orthotic Management for Peripheral Nerve Injuries of the Upper Extremity reviews the use of orthoses and how it relates to the treatment of median, ulnar, and radial nerve dysfunction.