"Rest is best" for carpal tunnel and similar repetitive-strain injuries, new research suggests.
Carpal tunnel syndrome is pressure on a nerve in the wrist, which causes tingling, numbness and pain in the hand and fingers. Recommended treatments can include wearing a wrist splint and taking paracetamol or ibuprofen for short-term pain relief.
In a study conducted in rats, US researchers found that a four-week period of rest was almost as effective as an experimental drug at reducing discomfort and regaining function.
The findings are relevant to treating human patients with common musculoskeletal disorders caused by overuse, such as tendinitis, tendinosis and low back pain, as well as carpal tunnel syndrome, the researchers believe.
"Rest appears to be a good first treatment choice," commented Amanda White, PhD, a postdoctoral fellow at Temple University who conducted the research along with Mary Barbe, PhD, professor at the Lewis Katz School of Medicine. "Other treatments following rest should include exercises to improve tissues, and pain reducers if needed. If symptoms do not subside and strength does not return following this approach, then pharmacological treatments may be needed to aid recovery."
For the study, rats were trained to repeatedly pull a lever, in order to model the types of repetitive-strain injuries humans experience. After 12 weeks, the animals showed signs of strain-induced tissue damage, including a weaker grip strength, discomfort and increased collagen production in the forearm.
The rats were then allowed to rest for four weeks, and one group also received an experimental drug that blocks a neurotransmitter, Substance P, which is associated with the sensation of pain.
"We found that the four-week rest treatment reduced collagen production, improved strength and decreased discomfort," White said. "The drug blocking Substance P signalling also had similar effects, and was somewhat better at improving grip strength, but at the same time made the animals less sensitive to very hot temperatures, which is concerning. This led us to conclude that rest may be the better treatment."
The researchers also noted, however, that while the study showed rest was sufficient for recovering from repeated moderate-strain activity, previous studies indicated it was not sufficient when the lever was harder to pull, causing more strain.