Introduction
Five percent of adults are affected by carpal tunnel syndrome (CTS), a neuropathy caused by entrapment and compression of the median nerve as it passes through the carpal tunnel of the wrist. Symptoms include numbness and pain in the medial side of the hand and the first three fingers. Later in the progression of this syndrome, muscle atrophy occurs, leading to a loss of motor function.
Traditional therapies have been the preferred treatment method for CTS, but a follow-up study found that only 60 to 70% of patients reported symptom relief with these methods (Katz, 1998). Corticosteroid injections provide immediate relief, but the effects only last about four weeks and come with serious side effects, such as degenerative tendon rupture (Kim, 2014). [Link to steroid article]. Surgery is recommended for severe cases; however, surgical failure rates of 7–75% are reported in the literature (Huisstede, 2010).
Platelet-rich plasma (PRP) offers a promising outcome for the treatment of neuropathies with low side effect risks. PRP is prepared from the patient’s own blood. The blood sample is spun to produce a platelet layer that contains a high concentration of platelets. These platelets contain growth factors that promote tissue regeneration and healing. PRP may also improve nerve regeneration in the entrapment area.
The Study
The authors conducted a meta-analysis of randomized controlled trials to document the efficacy and safety of PRP. Subjects had mild to moderately severe CTS. A total of nine studies with 434 patients were included in the review. Control groups were treated with corticosteroid injections in five trials, saline injections in one trial, and splints in three trials. The PRP groups received one injection under ultrasound guidance in six of the nine studies.
Outcome measures included a 10-point pain scale, symptom, and functional status measures. Secondary outcomes included sensory and motor nerve electrophysiology results.
Results
At one month post-treatment, five of the nine studies reported results. All groups reported less pain and symptoms, and there were no significant differences between groups except on the electrophysiology measure, with greater improvement in the PRP group.
At three months, significant differences were noted between groups for pain, symptoms, and function in three studies, with the PRP group showing greater effects. This study found promising outcomes in the PRP groups for symptoms of pain, tingling, and numbness, as well as the frequency and duration of these symptoms at three and six months. Compared to conservative treatment, PRP provided more effective long-term relief. There was no difference between groups at one month, as the steroids and hormones provided to the traditionally treated groups resulted in short-term symptom relief. The PRP group showed significant long-term benefits in nerve function compared to the corticosteroid groups.
In this meta-analysis, PRP had lasting effects on nerve function, which may indicate that the PRP injection reduced the swelling of flexor tenosynovitis. However, nerve recovery is a slow process that lasts about 18 months, and a study with a longer follow-up would be helpful.
Only one study reported side effects, which were increased pain within 48 hours of the injection. Overall, PRP treatment was found to be safe and effective.
Conclusion
Mild to moderate CTS can potentially be improved with PRP treatment. Interventions that promote nerve tissue regeneration are critical at these stages before the injury progresses to tissue atrophy. PRP contains high levels of growth factors that are closely associated with nerve regeneration. In this analysis, PRP was the only treatment that showed improved sensory and motor results, suggesting possible nerve tissue regeneration.
References
Dong, C., Sun, Y., Qi, Y., et al. (2020). Effect of platelet-rich plasma injection on mild or moderate carpal tunnel syndrome: An updated systematic review and meta-analysis of randomized controlled trials. BioMed Research International, 5089378. https://doi.org/10.1155/2020/5089378
Katz, J. N., Keller, R. B., Simmons, B. P., et al. (1998). Maine carpal tunnel study: outcomes of operative and nonoperative therapy for carpal tunnel syndrome in a community-based cohort. The Journal of Hand Surgery, 23(4):697–710. doi: 10.1016/S0363-5023(98)80058-0
Kim, H. J., Park, S. H. (2014). Median nerve injuries caused by carpal tunnel injections. The Korean Journal of Pain, 27(2):112–117. doi: 10.3344/kjp.2014.27.2.112
Huisstede, B. M., Hoogvliet, P., Randsdorp, M. S., Glerum, S., van Middelkoop, M., Koes, B. W. (2010). Carpal tunnel syndrome. Part I: effectiveness of nonsurgical treatments—a systematic review. Archives of Physical Medicine and Rehabilitation, 91(7):981–1004. doi: 10.1016/j.apmr.2010.03.022
