Carpal Tunnel Injection

Excerpt

Carpal tunnel syndrome (CTS) is a common ailment affecting the general patient population. It is the most common cause of peripheral nerve compression, with an incidence of 99 in 100,000 people. CTS is most commonly seen in patients over 40 years of age and has a greater prevalence in females. Females comprise approximately 65% to 75% of all reported cases . CTS results from compression of the median nerve within the carpal tunnel in the wrist. Typically the pressure within the carpal tunnel in these patients can be 32 to 110 mm Hg compared to 2 to 31 mm Hg in normal patients. The compression of the median nerve causes the classic pain distribution and/or parathesiass seen in CTS on the palmar aspect of the hand. The classic distribution invloves the area innervated by the median nerve to include the volar aspect of the thumb, index finger, long finger, and the radial volar half of the ring finger. Risk factors for the development of CTS include obesity, pregnancy (especially later in pregnancy), age, trauma to the wrist, and inflammatory rheumatic disorders. Controversy exists whether or not overuse is a contributing factor (such as daily typing). Conservative treatment options include keeping the wrist immobile using wrist splints, physiotherapy, and pain medications, both topically and systemically. More invasive options include local steroid injections to the carpal tunnel and surgical decompression of the space. This article will focus on injection techniques for CTS.

The exact etiology of CTS is not completely known, but the condition is largely assumed to be idiopathic or multifactorial. Some of the suspected risk factors for CTS include diabetes mellitus type 1 or 2, hypothyroidism, menopause, obesity, arthritis, and age. Diabetes seems to have the greatest association with CTS with a prevalence rate of 30% in patients with diabetic neuropathy and 14% in patients without neuropathic symptoms. Hormonal changes may be a contributing factor since pregnancy, menopause, and hypothyroidism are associated with CTS. Mechanical risk factors, including inflammation, thickening, arthritic deformity, and bony irregularities, contribute to median nerve compression.