Does a Different Local Anesthetic Improve Pain After Carpal Tunnel Release?

Description

A research nurse will meet with each patient presenting for outpatient CTR surgery at the Saskatoon City Hospital procedure room. He or she will obtain informed consent for interested participants. The patient will be assigned a subject number and be randomized to standard vs. bupivacaine treatment based on a computer algorithm. Participants will complete the Boston Carpal Tunnel Questionnaire as a baseline for comparison as well as a brief questionnaire on demographics. For those patients that are having both sides released during the study period, the first side will be randomized based on the study protocol and the second side will be anesthetized with the other treatment. They will be blinded to both procedures such that we can directly compare their operative experience.

The surgeon will draw up and mix the pre-determined local anesthetic (LA) for each patient based on the randomization protocol. The research nurse (who will be performing all assessments) and the patient will remain blinded to the type of anesthetic.

The two types of anesthetic will be:

1. 10 mL 1% lidocaine with 1:100,000 epinephrine and 1 mL 8.4% sodium bicarbonate (standard treatment)
2. 5 mL 1% lidocaine with 1:100,000 epinephrine + 5 mL 0.5% bupivacaine with 1:100,000 epinephrine and 1 mL 8.4% sodium bicarbonate (bupivacaine treatment)

The participants will be anesthetized in the standard fashion, with all 11 mL of LA infiltrated subcutaneously into the area of the incision. After a delay of 20-40 minutes, the CTR will be carried out using the standard mini-open approach. Patients will be provided with the standard post-operative instructions regarding activity and wound care.

After the procedure, participants will complete a short questionnaire (VAS) about any pain experienced during the administration of the local anesthetic and during the procedure. Patients will be sent home with instructions to complete a pain and numbness assessment at 2, 4, 6, 8, and 10 hours after surgery. They will be provided with a form containing the VAS and the times at which they are to self-administer this pain scoring system. Additionally, they will be provided with 20 Tylenol tablets (325mg each) and 20 ibuprofen tablets (200mg each), with instructions to take 1-2 tablets of one or both analgesics every 6 hours as needed during the first 24 hours. They will be asked to document the times at which they took the medications, as well as the dosages taken. They will be asked to refrain from using other types of pain medications, if possible. They will also be asked to document use of any other analgesics including Cannabis. Any questions will be answered by the research nurse before leaving clinic.

The day after surgery, at the 24 hour mark, the research nurse will call each patient and inquire about their pain scores and numbness at 2, 4, 6, 8, and 10 hours, as well as the present time (24 hours). He or she will also ask about the number of Tylenol and/or ibuprofen pills taken during the first 24 hours, as well as the timing of consumption. This information recorded on a password-protected datasheet which contains only the subject number (no identifiers).

The patient will return for their standard follow-ups. At 3 months, the research nurse will repeat the Boston Carpal Tunnel Questionnaire to assess outcome. At this time, if the patient wishes, they may be unblinded.

For patients wishing for bilateral CTR, the first will be performed according to the randomization protocol as described above. The contralateral CTR will be performed 2-8 weeks later (as standard in our practice), with the alternate anesthetic (e.g. first CTR with standard treatment, second CTR with bupivacaine treatment). The same post-operative assessment will be performed for the second CTR. Patients will remain blinded to their type of anesthetic in each wrist until 3 months after the second surgery is performed. At that time, they will be asked by the research nurse whether the first or second surgery provided a better pain experience. Only after this will they be unblinded, if desired.

Details