Surgical versus non-surgical treatment for carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is a compression neuropathy of the median nerve at the wrist. Surgery is considered when symptoms persist despite the use of non-surgical treatments. It is unclear whether surgery produces a better outcome than non-surgical therapy. This is an update of a Cochrane review published in 2008.

To assess the evidence regarding the benefits and harms of carpal tunnel release compared with non-surgical treatment in the short (< 3 months) and long (> 3 months) term.

In this update, we included studies from the previous version of this review and searched the Cochrane Neuromuscular Specialised Register, CENTRAL, Embase, MEDLINE, ClinicalTrials.gov and WHO ICTRP until 18 November 2022. We also checked the reference lists of included studies and relevant systematic reviews for studies.

We included randomised controlled trials comparing any surgical technique with any non-surgical therapies for CTS.

We used the standard methodological procedures expected by Cochrane.

The 14 included studies randomised 1231 participants (1293 wrists). Eighty-four per cent of participants were women. The mean age ranged from 32 to 53 years, and the mean duration of symptoms from 31 weeks to 3.5 years. Trial sizes varied from 22 to 176 participants. The studies compared surgery with: splinting, corticosteroid injection, splinting and corticosteroid injection, platelet-rich plasma injection, manual therapy, multimodal non-operative treatment, unspecified medical treatment and hand support, and surgery and corticosteroid injection with corticosteroid injection alone. Since surgery is generally used for its long-term effects, this abstract presents only long-term results for surgery versus splinting and surgery versus corticosteroid injection. 1) Surgery compared to splinting in the long term (> 3 months) Surgery probably results in a higher rate of clinical improvement (risk ratio (RR) 2.10, 95% confidence interval (CI) 1.04 to 4.24; 3 studies, 210 participants; moderate-certainty evidence). Surgery probably does not provide clinically important benefit in symptoms or hand function compared with splinting (moderate-certainty evidence). The mean Boston Carpal Tunnel Questionnaire (BCTQ) Symptom Severity Scale (scale 1 to 5; higher is worse; minimal clinically important difference (MCID) = 1) was 1.54 with splint and 0.26 points better with surgery (95% CI 0.52 better to 0.01 worse; 2 studies, 195 participants). The mean BCTQ Functional Status Scale (scale 1 to 5; higher is worse; MCID 0.7) was 1.75 with splint and 0.36 points better with surgery (95% CI 0.62 better to 0.09 better; 2 studies, 195 participants). None of the studies reported pain. Surgery may not provide better health-related quality of life compared with splinting (low-certainty evidence). The mean EQ-5D index (scale 0 to 1; higher is better; MCID 0.074) was 0.81 with splinting and 0.04 points better with surgery (95% CI 0.0 to 0.08 better; 1 study, 167 participants). We are uncertain about the risk of adverse effects (very low-certainty evidence). Adverse effects were reported amongst 60 of 98 participants (61%) in the surgery group and 46 of 112 participants (41%) in the splinting group (RR 2.11, 95% CI 0.37 to 12.12; 2 studies, 210 participants). Surgery probably reduces the risk of further surgery; 41 of 93 participants (44%) were referred to surgery in the splinting group and 0 of 83 participants (0%) repeated surgery in the surgery group (RR 0.03, 95% CI 0.00 to 0.21; 2 studies, 176 participants). This corresponds to a number needed to treat for an additional beneficial outcome (NNTB) of 2 (95% CI 1 to 9). 2) Surgery compared to corticosteroid injection in the long term (> 3 months) We are uncertain if clinical improvement or symptom relief differs between surgery and corticosteroid injection (very low-certainty evidence). The RR for clinical improvement was 1.23 (95% CI 0.73 to 2.06; 3 studies, 187 participants). For symptoms, the standardised mean difference (SMD) was -0.60 (95% CI -1.88 to 0.69; 2 studies, 118 participants). This translates to 0.4 points better (95% CI from 1.3 better to 0.5 worse) on the BCTQ Symptom Severity Scale. Hand function or pain probably do not differ between surgery and corticosteroid injection (moderate-certainty evidence). For function, the SMD was -0.12 (95% CI -0.80 to 0.56; 2 studies, 191 participants) translating to 0.10 points better (95% CI 0.66 better to 0.46 worse) on the BCTQ Functional Status Scale with surgery. Pain (0 to 100 scale) was 8 points with corticosteroid injection and 6 points better (95% CI 10.45 better to 1.55 better; 1 study, 123 participants) with surgery. We found no data to estimate the difference in health-related quality of life (very low-certainty evidence). We are uncertain about the risk of adverse effects and further surgery (very low-certainty evidence). Adverse effects were reported amongst 3 of 45 participants (7%) in the surgery group and 2 of 45 participants (4%) in the corticosteroid injection group (RR 1.49, 95% CI 0.25 to 8.70; 2 studies, 90 participants). In one study, 12 of 83 participants (15%) needed surgery in the corticosteroid group, and 7 of 80 participants (9%) needed repeated surgery in the surgery group (RR 0.61, 95% CI 0.25 to 1.46; 1 study, 163 participants).

Currently, the efficacy of surgery in people with CTS is unclear. It is also unclear if the results can be applied to people who are not satisfied after trying various non-surgical options. Future studies should preferably blind participants from treatment allocation and randomise people who are dissatisfied after being treated non-surgically. The decision for a patient to opt for surgery should balance the small benefits and potential risks of surgery. Patients with severe symptoms, a high preference for clinical improvement and reluctance to adhere to non-surgical options, and who do not consider potential surgical risks and morbidity a burden, may choose surgery. On the other hand, those who have tolerable symptoms, who have not tried non-surgical options and who want to avoid surgery-related morbidity can start with non-surgical options and have surgery only if necessary. We are uncertain if the risk of adverse effects differs between surgery and non-surgical treatments. The severity of adverse effects may also be different.