Steroid Injections
Strong evidence supports that the use of steroid (methylprednisolone) injection should improve patient reported outcomes.

There is one high quality study (Atroshi 2013) that directly compares the use of steroid injection to placebo to treat carpal tunnel syndrome.  In a prospective, randomized, double-blinded, placebo controlled study, the efficacies of 40mg methylprednisolone and 80mg methylprednisolone were compared to placebo injection at various time lines (10 weeks and 1 year). At 10 weeks, there was greater improvement in the CTS symptom severity score in the group receiving injections of 40mg or 80mg methylprednisolone (p<0.003) versus placebo injections; but there was no difference amongst the groups at 1 year.  However, patients receiving 80mg methylprednisolone injection were less likely to go on to need surgery than placebo injection (p=0.04). A small p-value (p<.05) indicates that this difference was not observed due to chance, subsequently favoring the alternative hypothesis of methylprednisolone injection improving patient outcomes.
Several high quality studies (Dammers 2006[1-3], Wong 2001, and Wong 2005) compare various doses of injected or routes of administration of methylprednisolone to treat carpal tunnel syndrome.  In a double blinded, randomized study, Dammers 2006 compare the efficacy of 20, 40, and 60mg methylprednisolone injections to treat carpal tunnel syndrome. There was no significant difference in treatment response at 1 year. In a randomized double blind controlled trial, Wong 2005 compare a the effects of a single 80mg methylprednisolone injection with saline injection at 8 weeks versus two 80mg methylprednisolone injections 8 weeks apart. There was no significant difference between groups respect to Global Symptom Score, electrophysiological study, or functional outcomes (p=0.26). In a prospective randomized double-blind study, Wong 2001 compared 25mg methylprednisolone orally for 10 days and placebo injection to 15mg methylprednisolone injection with oral placebo. The steroid injection provided significant improvement based on Global Symptom Score at 12 weeks.