Carpal tunnel syndrome (CTS) is a medical condition due to compression of the median nerve as it travels through the wrist at the carpal tunnel.[1] The main symptoms are pain, numbness and tingling, in the thumb, index finger, middle finger, and the thumb side of the ring fingers.[1] Symptoms typically start gradually and during the night.[2] Pain may extend up the arm.[2] Weak grip strength may occur and after a long period of time the muscles at the base of the thumb may waste away.[2] In more than half of cases both sides are affected.[1]
Generally accepted treatments include: physiotherapy, steroids either orally or injected locally, splinting, and surgical release of the transverse carpal ligament.[3] However, recent evidence has emerged from the world of acupoint injection therapy in which the application of a local anesthetic, particularly procaine (the preferred and recommended local anesthetic by ARIABC) by injection around the wrist can provide similar relief to carpel tunnel syndrome as steroids injected locally.
Two studies conducted by the same team 1 year apart set out to compare the efficacy of triamcinolone acetonide (corticosteroid) and that of procaine (local anesthetic).
The first study published in 2011 divided 99 patients into 3 groups[4]. Group 1 received 40 mg of triamcinolone acetonide, group 2 received 4 ml of 1% procaine HCl, and group 3 received both 40 mg of triamcinolone acetonide and 4 ml of 1% procaine HCl. The patients were injected 1 cm proximal to the distal wrist-flexion crease, between the palmaris longus and the flexor carpi radialis tendons. Each patient was injected only once. The results at two and six months after the treatment showed that group 3 (combination of steroids and local anesthetic) benefited the most, but there was no significant differences between group 1 (steroids) and group 2 (local anesthetic).
The study was repeated in 2012 which divided 102 patients into 3 groups [5]. Group 1 was injected with 1 ml 0.09% saline (placebo), group 2 was injected with 40 mg triamcinolone acetonide, and group 3 was injected with 4 ml 1% procaine HCl. The location of the injection was the same as the previous study, each patient was injected only once. The results showed significant improvements in both group 2 (steroids) and group 3 (local anesthetic) after two and six months without any significant difference between the two groups. No significant changes were observed in group 1 (placebo).
These results led the authors of the studies to conclude that steroid and procaine HCl injections are effective in carpel tunnel syndrome regarding short- and long-term outcomes compared with placebo injections, and local procaine HCl injection was as effective in reducing the symptoms of carpel tunnel syndrome and improving electrophysiological findings as steroid injection. Procaine HCl can be used in carpel tunnel syndrome patients in whom steroid use is contraindicated, such as those with diabetes mellitus.
If both corticosteroids and procaine have the same outcome, why should you opt for procaine over a corticosteroid? The main reason is the potential side effect profile of corticosteroids.
Corticosteroids have been shown in a 2014 systematic review to have a wide range of side effects that are detrimental to long term tendon health such as; loss of collagen organisation, collagen necrosis, reduction in the proliferation and viability of fibroblasts, collagen synthesis was decreased, increase in inflammatory cell infiltrate and an increased cellular toxicity.[6] The meta-analysis revealed a significant deterioration in mechanical properties of tendons leading the authors to conclude their paper with the following statements.
Overall it is clear that the local administration of glucocorticoid has significant negative effects on tendon cells in vitro, including reduced cell viability, cell proliferation and collagen synthesis. There is increased collagen disorganisation and necrosis as shown by in vivo studies. The mechanical properties of tendon are also significantly reduced. This review supports the emerging clinical evidence that shows significant long-term harms to tendon tissue and cells associated with glucocorticoid injections. - Dean et al 2014[6]
REFERENCES
- Burton, C; Chesterton, LS; Davenport, G (May 2014). "Diagnosing and managing carpal tunnel syndrome in primary care.". The British journal of general practice : the journal of the Royal College of General Practitioners 64(622): 262–3. PMID 24771836
- Carpal Tunnel Syndrome Fact Sheet". National Institute of Neurological Disorders and Stroke. January 28, 2016.
- Piazzini, DB; Aprile, I; Ferrara, PE; Bertolini, C; Tonali, P; Maggi, L; Rabini, A; Piantelli, S; Padua, L (Apr 2007). "A systematic review of conservative treatment of carpal tunnel syndrome". Clinical rehabilitation 21 (4): 299–314.doi:10.1177/0269215507077294. PMID 17613571.
- Karadaş O, Tok F, Ulaş UH, Odabaşi Z. "The effectiveness of triamcinolone acetonide vs. procaine hydrochloride injection in the management of carpal tunnel syndrome: a double-blind randomized clinical trial" in Am J Phys Med Rehabil. 2011 Apr;90(4):287-92. doi: 10.1097/PHM.0b013e31820639ec.
- Karadaş O, Tok F, Ulaş UH, Odabaşi Z. "Triamcinolone acetonide vs procaine hydrochloride injection in the management of carpal tunnel syndrome: randomized placebo-controlled study." in J Rehabil Med. 2012 Jun;44(7):601-4. doi: 10.2340/16501977-0990.
- Dean BJ. "The risks and benefits of glucocorticoid treatment for tendinopathy: A systematic review of the effects of local glucocorticoid on tendon" in Seminars in Arthritis and Rheumatism 43, Issue 4 (February 2014) pp. 570-576. http://www.semarthritisrheumatism.com/article/S0049-0172(13)00173-X/fulltext