gms | German Medical Science

Objectives/Interrogation: This study aims to obtain the most favorable syringe and needle combination, which causes the least pain during local anesthesia tumescent injection in the simulation of fully awake hand surgery.

Methods: A randomized single-blinded controlled trial is designed for 30 adult male healthy subjects to compare the pain from injection using syringe and needle combination i.e. 1) 1 cc syringe with 26G needle, 2) 3 cc syringe with 26 G needle, and 3) 5 cc needle with 26 G needle. The injection will be performed in any of at the second, third and fourth fingers of either subject's hand randomly. The injection will be SIMPLE block technique using 1 cc of NaCl 0.9% solution under the injection speed of 30 seconds/cc. Subjects are required to rate three check-point of VAS at the timing of needle puncture, initial tumescent solution injection and just right after the completion of the infiltration. Upon the completion of each finger, the subject is also asked to give a response to a series of questions regarding the procedures. At the end of all injections, the subject is asked to rate his preference of syringe and needle combination.

Results and Conclusions: 90 fingers were randomized, we assume no differences between all finger that were tested. No adverse events were noted. The mean VAS score at the timing of needle puncture for 1 cc syringe with 26G needle, 3 cc syringe with 26 G needle, and 5 cc needle with 26 G needle are 0.76, 0,72 and 0.63 respectively. The mean VAS score at the initial tumescent solution injection for 1 cc syringe with 26G needle, 3 cc syringe with 26 G needle, and 5 cc needle with 26 G needle are 0.88, 0.75 and 0.74 respectively. The mean VAS score right after the completion of the infiltration or 1 cc syringe with 26G needle, 3 cc syringe with 26 G needle, and 5 cc needle with 26 G needle are 0.85, 0.87 and 0.71 respectively. We found no correlation between syringe-needle combinations to VAS Score at three different checkpoints and patient preferences (p<0,05). In our knowledge, this the first study to translate the variance in Initial Force and Maintenance Force of a syringe-needle combination into a subjective perceptible pain in the clinical setting. We postulate that the difference of forces among combinations in this study is too small to be recognized by VAS Score. The findings in this study have promoted the equal safety, usability and comfort of either 1, 3 and 5 cc syringe with 26 G needle combinations for local tumescent injection in fully awake hand surgery.