Analgesia efficacy of lidocaine transfused by a novel disposable injectable cervical dilator during intrauterine device removal procedure: A randomized clinical trial.

Objective: The majority of intrauterine devices (IUDs) inserted in China are tailless, requiring intrauterine manipulations for removal and causing pain. This study aimed to investigate the analgesic efficacy of lidocaine injection into a novel disposable injectable cervical dilator for IUD removal procedures.

Study Design: A double-blinded, placebo-controlled, randomized clinical trial was conducted with women aged 18-65 years old requesting outpatient IUD removal. The study randomly assigned participants to either lidocaine (injecting 5 ml of 2% lidocaine into the injectable cervical dilator) or placebo (injecting 5 ml of normal saline into the device) group. All participants received a standardized paracervical block. The primary outcome was pain reported during IUD removal on a 100 mm Visual Analog Scale (VAS). Intention-to-treat were conducted to evaluate the analgesic effectiveness of injecting lidocaine into the injectable cervical dilators.

Results: We enrolled seventy-four eligible participants (37 in lidocaine group and 37 in placebo group). The results showed that the median intraoperative VAS score in the lidocaine group was lower than the placebo group (30.0 mm [IQR 20.0-46.0, n = 37] vs 46.0 mm [IQR 30.0-55.0, n = 37], p = 0.01. In subgroup analyses, among participants with IUD removal and without uterine manipulation and additional procedures, there was no statistically significant disparity observed in intraoperative VAS scores between the lidocaine and placebo group (15.0 mm [IQR 10.0-27.5, n = 8] vs 20.0 mm [IQR 20.0-40.0, n = 6]), p = 0.28). Among participants with an IUD removal necessitating intrauterine manipulations and without additional procedures, showing lower intraoperative VAS scores in lidocaine group (25.0 mm [IQR 15.0-40.5, n = 17]) compared to placebo group (46.0 mm [IQR 38.5-50.0, n = 23]), p < 0.01. Among participants with additional procedures in addition to IUD removal, there was no statistically significant disparity observed in intraoperative VAS scores between the lidocaine and placebo group (41.0 mm [IQR 32.5-57.5, n = 12] vs 45.0 mm [IQR 22.5-69.0, n = 8]), p = 0.97).

Conclusions: Injecting lidocaine into the novel disposable injectable cervical dilator for cervix dilation can significantly reduce pain during an IUD removal, particularly in patients necessitating intrauterine manipulations during IUD removal.

Implications: When we have to perform intrauterine manipulations to remove an IUD, surgical pain and narrow cervical canal undoubtedly affect the implementation of the procedure. Injecting lidocaine into the injectable cervical dilator can achieve local anesthesia while dilating the cervix, and might reduce the choice of general anesthesia for IUD removal.