Abstract

Background

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.

Objectives

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.

Search methods

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.

Selection criteria

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

Data collection and analysis

We used the standard methodological procedures expected by Cochrane.

Main results

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).

Authors' conclusions

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.

Author(s)

Vieda Lusa, Teemu V Karjalainen, Markus Pääkkönen, Tuomas Jaakko Rajamäki, Kati Jaatinen

Abstract

Plain language summary

Surgical versus non‐surgical treatment for carpal tunnel syndrome

Surgery or non‐surgical treatment: which works better for carpal tunnel syndrome?

Key messages

Surgery probably results in a higher rate of clinical improvement than splinting after a follow‐up of 6 to 12 months. The evidence on which of the two treatments may have less harmful effects is uncertain.

The evidence is uncertain if clinical improvement or the rate of harmful effects differ between surgery and corticosteroid injection after a follow‐up of 6 to 12 months.

Generally, we lack confidence about the efficacy of surgery in people with carpal tunnel syndrome because we did not find studies comparing surgery with placebo surgery or no treatment. Future studies should address this evidence gap.

What is carpal tunnel syndrome?

Carpal tunnel syndrome is a condition in which the median nerve at the wrist is compressed, causing numbness, tingling in the thumb, index and middle finger, and pain. In severe cases, skin sensation can be permanently diminished and compression may cause muscle wasting at the base of the thumb.

How is carpal tunnel syndrome treated?

Usually, non‐surgical treatments such as splints, corticosteroid injections, exercises and manual therapy are offered as first‐line treatments. Surgery is considered for people with persisting symptoms and sometimes as the primary treatment for people with severe symptoms.

What did we want to find out?

If surgery or non‐surgical treatment is more beneficial and less harmful for treating carpal tunnel syndrome.

What did we do?

We searched for studies that compared surgery with 1) no treatment or placebo treatment, or 2) any non‐surgical treatment. We compared the rate of clinical improvement, symptoms, hand function, pain and health‐related quality of life, as well as harmful effects and need for further surgery. We collected and analysed data according to Cochrane methods.

What did we find?

We found 14 studies randomising 1231 people: mean age ranged between 32 and 53 years; 84% female; representing nine countries from Asia, Europe and North America; symptom duration 31 weeks to 3.5 years with a varying degree of severity. Surgery was compared with 1) splinting, 2) corticosteroid injection, 3) splinting and corticosteroid injection, 4) platelet‐rich plasma injection, 5) manual therapy (three 30‐minute treatment sessions including desensitisation manoeuvres, once per week), 6) multimodal non‐operative treatment (combination of six visits of hand therapy, activity modification, nonsteroidal anti‐inflammatory drugs, splinting, followed by ultrasound treatment if needed), 7) unspecified medical treatment and hand support. Additionally, one study compared corticosteroid injection with surgery plus corticosteroid injection. Two studies reported including people who had been unresponsive to at least 2 weeks of non‐surgical treatment. Study sizes varied from 22 to 176 people. Ten studies measured outcomes at long‐term follow‐up (over 3 months, usually 6 or 12 months).

We did not find studies comparing surgery with placebo surgery or no treatment.

Key results

Because surgery is often used for its long‐term effects, this summary focusses on long‐term follow‐up (6 to 12 months).

Surgery compared to splinting

Surgery probably results in a higher rate (twice) of clinical improvement compared with splinting. However, surgery may not be more beneficial than splinting for improving symptoms or hand function, or general health‐related quality of life.

We are uncertain if the risk of harmful effects differs between surgery and splinting. Some people in the splinting group had surgery‐related harms because they had undergone surgery before the outcomes were measured. However, surgery probably reduces the need for further surgery.

Surgery compared to corticosteroid injection

We are uncertain if clinical improvement, symptom relief, risk of harmful effects and the need for further surgery differ between surgery and corticosteroid injection. Hand function or pain probably do not differ considerably.

Other comparisons

Surgery is probably slightly more beneficial than multimodal non‐operative treatment for improving symptoms, but may not provide benefits for other outcomes.

Surgery probably results in a higher rate of clinical improvement than manual therapy (1.6 times) but may not provide benefits for other outcomes.

We are uncertain if surgery provides more benefits compared with a combination of splint and corticosteroid injection.

What are the limitations of the evidence?

The most important limitation is that there is no existing evidence to determine whether surgery is better than no treatment or if surgery is more effective than continuing non‐surgical treatments for people who have not improved with non‐surgical interventions. Additionally, it is unclear if surgery could provide more long‐lasting effects after several years' follow‐up.

Our confidence in the evidence regarding the differences between surgery and non‐surgical treatment was mostly affected by the fact that people in all the studies were aware of which treatment they received. This may affect how people report the outcomes and result in biased estimations of treatment effects. Furthermore, in two large studies, up to 40% of people, who were randomised to non‐surgical treatment, opted for surgery during the study and had already undergone it by the time long‐term outcomes were measured. If these people had not had surgery, their outcomes might have been worse, with the resulting benefits of surgery being underestimated.

How up‐to‐date is this evidence?

The evidence is up‐to‐date until November 2022.

Author(s)

Vieda Lusa, Teemu V Karjalainen, Markus Pääkkönen, Tuomas Jaakko Rajamäki, Kati Jaatinen

Reviewer's Conclusions

Authors' conclusions 

Implications for practice 

The efficacy of carpal tunnel release in people with carpal tunnel syndrome (CTS) is unclear, since we identified no studies comparing it with placebo or no treatment.

At short‐term follow‐up (up to 3 months), surgery may not provide clinically important benefits compared to various non‐operative treatments, but our conclusions are limited by risk of bias, inconsistency and often imprecision of the outcomes. However, people most likely consider surgery because it can provide long‐term improvements, with short‐term results likely to be secondary in clinical decision‐making.

At long‐term follow‐up, surgery probably provides better clinical improvement compared with splinting and manual therapy, but the benefits of surgery in symptoms and hand function seem to be small compared with non‐surgical treatment. 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, have not tried non‐surgical options and want to avoid surgery‐related morbidity can start with non‐surgical options and have surgery only if they fail to achieve a satisfactory symptom state with non‐surgical options. However, at the moment, we do not know if surgery is better than continuing non‐surgical treatments in people who are not satisfied with the outcomes of non‐surgical options.

We are uncertain if the risk of adverse effects differs between surgery and non‐surgical treatments. The severity of adverse effects may differ between surgery and non‐surgical options, with surgery potentially causing rare severe adverse effects, such as deep wound or systemic infection or nerve injury, which are not plausible risks in non‐surgical care. This may be explained to people who consider opting for surgery.

Implications for research 

A placebo‐surgery‐controlled study assessing the efficacy of carpal tunnel release would be helpful in clinical decision‐making in people considering surgery. From the clinical point of view, the most useful information would probably come from a study randomising people who are not satisfied with non‐surgical interventions, since this is the population that usually deliberates about whether to undergo surgery.

Similarly, comparisons of surgery and non‐surgical interventions should primarily recruit people who have already exhausted non‐surgical options. If, however, treatment‐naive patients are randomised to surgery versus a non‐surgical option (or a combination of them), long‐term (up to several years) follow‐up is recommended, because long‐term outcomes could impact clinical decision‐making; a high rate of conversion to surgery could influence some people to choose surgery initially, despite small benefits during the first year.

Optimally, future studies should use rigorous methods, including blinding the participants and study personnel from treatment allocation to minimise sources of bias, and plan strategies to minimise early switching to surgery to avoid bias arising from it.

In the included studies, few participants had severe CTS. This population was probably excluded in most trials because surgery is considered the primary option in this population. However, since we failed to find evidence supporting large benefits from surgery compared with non‐surgical treatments, a study randomising people at a severe stage may be appropriate.

Furthermore, more evidence is needed on the minimal clinically important difference of the Boston Carpal Tunnel Questionnaire to help to interpret the results of trials and meta‐analyses.

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