Evaluation of a needle-free injection system for local anaesthesia prior to venous cannulation

The Anesthetic Effectiveness of J-Tip Needle-Free Injection System Prior to Trigger Finger Injection: A Double-Blind Randomized Clinical Trial

Background: The aim of this preliminary study was to evaluate the effectiveness of a J-tip needle-free injection system (JNFS) to reduce pain associated with corticosteroid injection of the tendon sheath for treatment of trigger finger. Methods: Thirty-four consecutive trigger fingers occurring in 28 unique patients who met inclusion/exclusion criteria were consented and enrolled into this double-blind randomized controlled study. Patients were randomly assigned to the control (JNFS loaded with sterile normal saline) or treatment group (JNFS loaded with buffered 1% lidocaine). Both the fellowship-trained hand surgeon and patient were blinded to the allocation group. Prior to each trigger finger injection, each patient rated pain associated with stubbing toe and papercut on the visual analog scale (VAS), in addition to a postprocedure VAS pain score. Results: A total of 28 patients and 34 digits were enrolled in this study. There was no difference in patient demographics or preintervention pain perception between the control and treatment groups. The use of JNFS demonstrated lower mean pain VAS score when comparing the control group (n = 17) with the treatment group (n = 17), with VAS pain scores of 49 (SD = 31) and 39 (SD = 36), respectively. However, this difference was not statistically significant (P = .389). Conclusions: The use of JNFS loaded with 1% buffered lidocaine may reduce pain associated with trigger finger injections, although our results did not find a statistically significant difference. We hypothesize that the pain caused by the acidity of lidocaine is the primary driver of pain and discomfort during injection, and the pain from the needle stick is secondary. As a result, any pain reduction from JNFS is masked by the most painful part of injection-the delivery of injectate. Based on the findings and experience obtained from this study, we hypothesize that a follow-up study using buffered lidocaine may be able to better reveal the benefits of JNFS.