An interventional study of Sodium bicarbonate and Control arm in Carpal Tunnel Syndrome, sponsored by Kuopio University Hospital. Active, not recruiting at 1 site in Finland. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-09-16.
Sponsored by Kuopio University Hospital · Not applicable, Interventional, and Treatment
Introduction Carpal tunnel syndrome (CTS) is the most common peripheral nerve entrapment syndrome in Finland and worldwide. Nowadays carpal tunnel release (CTR) surgery is often done in local anaesthesia. Often the most painful event during CTR is the injection of the local anaesthetic. Multiple different methods have been trialed and buffering the local anaesthetic seems to have good results in reducing the pain caused by the injection. However, no study has buffered long-acting local anaesthetic in CTR surgery, and no study has accounted for the patient's individual pain tolerance in the groups. There are no comparisons of the results to minimal clinically important difference (MCID) for pain.
Hypothesis In this study the investigators will evaluate the effects of buffering long-lasting local anaesthetic in wide-awake local anaesthesia no tourniquet (WALANT) CTR. This study's hypothesis is that buffering long-acting local anaesthetic with sodium bicarbonate decreases the pain of the injection.
The investigators also expect that buffering will reduce the number of needle stings felt during injection, will result in as good perioperative pain control, will lengthen the effect of anaesthetic, will reduce postoperative painkiller usage, will have at least as good functional outcome and greater patient satisfaction.
Methods This study will enlist 116 patients and divide the patients into two groups in this double blinded randomized controlled trial. One group receives non-buffered, and the second group buffered local anaesthetic. This study's primary outcome is to compare burning, pressure, needle sting and total pain the patient experienced between the groups. The investigators will assess this using VAS, and will compare the results to MCID. The investigators secondary outcomes are comparisons of expected injection pain level and pain during CTR with VAS, individual pain tolerance/catastrophising tendency with preoperative PCS-FINv2.0 form, the number of needle stings the patient feels during the injection, functional outcome and improvement of the patients' symptoms with The Boston Carpal Tunnel Questionnaire (Likert 5) before and after the surgery, evaluation of patient satisfaction with net promoter score (NPS) and the use of painkillers, duration of analgesia and pain levels using VAS after the surgery until the 3rd postoperative night.
589 studies on the registry are indexed under Carpal Tunnel Syndrome; 139 are open to participants now.
This study's enrollment of 116 is above the median of 60 across 445 interventional studies indexed under Carpal Tunnel Syndrome.
Browse Carpal Tunnel Syndrome studies →Kuopio University Hospital is the lead sponsor of 132 studies on the registry; 23 are open to participants now.
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Exclusion Criteria:
The investigators allocate 58 patients in this arm. It serves as the control group, who receives currently used local anaesthetic solution.
Other: Control arm
The investigators allocate 58 patients in this arm. It serves as the experimental group, who receives currently used anaesthetic solution that has been buffered.
Other: Sodium bicarbonate
A 50/50 solution of lidocaine with adrenalin 1% and bupivacaine with adrenalin 0.5% is buffered with 7.5% sodium bicarbonate in 1:10.
A 50/50 solution of lidocaine with adrenalin 1% and bupivacaine with adrenalin 0.5%.
Total pain level with visual analogic scale (VAS)
The investigators evaluate the total pain with 0-100 mm visual analogue scale (VAS). In VAS higher number means more pain and is therefore worse. The investigators calculate the mean VAS level for each group and compare the results to find statistically and clinically relevant difference. Clinically relevant difference is evaluated by comparing the VAS difference to MCID.
Time frame: VAS is recorded immediately after the injection of local anaesthetic.
Burning pain level with VAS
The investigators evaluate the total pain with 0-100 mm visual analogue scale (VAS). In VAS higher number means more pain and is therefore worse.
Time frame: VAS is recorded immediately after the injection of local anaesthetic.
Pressure pain level with VAS
The investigators evaluate the total pain with 0-100 mm visual analogue scale (VAS). In VAS higher number means more pain and is therefore worse.
Time frame: VAS is recorded immediately after the injection of local anaesthetic.
Needle sting pain level with VAS
The investigators evaluate the total pain with 0-100 mm visual analogue scale (VAS). In VAS higher number means more pain and is therefore worse.
Time frame: VAS is recorded immediately after the injection of local anaesthetic.
CTR pain level
The investigators evaluate the maximum pain level patient experiences during CTR surgery with visual analogue scale (VAS). This study uses 0-100 mm VAS. In VAS higher number means more pain and is therefore worse.
Time frame: VAS is recorded right after CTR surgery
Analgesia duration
The investigators assess the length of the anaesthesia by recording the pain level with visual analogue scale (VAS) every 4 hours. This study uses 0-100 mm VAS. In VAS higher number means more pain and is therefore worse.
Time frame: Every 4 hours after the surgery until 3rd postoperative night.
Painkiller consumption
The investigators record the painkiller consumption after the surgery.
Time frame: After the surgery until 3rd postoperative night.
Number of needle stings
The investigators ask the patient to report how many needle stings the patient felt during the injection of the local anaesthetic.
Time frame: Immediately after the injection of local anaesthetic.
Pain catastrophizing tendency
The investigators ask the patients to fill pain catastrophizing tendency evaluating form (PCS-FINv2.0) before the surgery in order to evaluate the pain levels between the experimental and control group. It has 13 questions and scores between 0-52. Higher score means higher pain catastrophizing tendency.
Time frame: Before the surgery.
Functional outcome
The investigators ask the patients to evaluate symptoms and functional outcome using the Boston Carpal Tunnel Questionnaire (BTCQ). It has 11 questions for symptoms of carpal tunnel syndrome and scores between 11 and 55. Higher score means more symptoms. BTCQ also has 8 questions for functionality of hand and it has scores between 8 and 40. Higher scores mean worse function of the hand.
Time frame: Before and 3 months after the surgery.
Patient satisfaction
The investigators ask the patients to evaluate the surgery experience with net promoter score (NPS). NPS has 10 steps and higher value indicates greater satisfaction.
Time frame: 3 months after the surgery.
Expected pain level
The investigators ask the patients to evaluate the pain the patient expect to experience during administration of local anaesthetic using visual analogue scale (VAS). This study uses 0-100 mm VAS. In VAS higher number means more pain and is therefore worse.
Time frame: Before the surgery.
Documents are hosted by the registry — open the source record to download them.
Plan to share: Yes — The investigators share pseudonymised data in EU/ETA if it is separately requested.
Supporting information: Study protocol, Sap, Icf, Csr, Analytic code
This study is active, not recruiting, as verified in Sep 2025. You cannot join it, but the record below documents what was studied.
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Kuopio University Hospital