The Anatomical Distribution of the Pudendal Nerve Block Injection: A Cadaveric Study.

OBJECTIVE: The objective of this study was to assess the accuracy of commonly used injection locations of the pudendal nerve block by examining the proximity of the injected dye to the pudendal nerve in a cadaveric model. METHODS: Pudendal block injections at 4 sites were placed transvaginally on 5 cadaveric pelvises. These sites were 1 cm proximal to the ischial spine (black dye), at the ischial spine (red dye), 1 cm distal to the ischial spine (blue dye), and 2 cm lateral and 2 cm distal to the ischial spine (green dye). The cadavers were dissected via a posterior approach. RESULTS: We measured the shortest distance from the center of the dye-stained tissue to the pudendal nerve. As expected, the injections at the ischial spine (red) resulted in a distribution of dye closest to the pudendal nerve, averaging 3.0 ± 0.95 mm. Dyes at other sites were close to the nerve: 3.1 ± 1.00 mm (black), 3.6 ± 1.14 mm (blue), and 4.05 ± 1.28 mm (green). CONCLUSIONS: Regardless of the injection site, all dyes were close the pudendal nerve, indicating accuracy. We observed wide variation in the dye distribution even though all injections were performed by the same provider, implicating lack of precision. Based on our findings, we propose that the most effective injection location is at the ischial spine because it is the closest to the pudendal nerve; however, all injections were within 4 mm of the pudendal nerve, suggesting that only 1 to 2 injections may be sufficient.

Use of pelvic model-based simulation for sacrospinous ligament fixation education in novice learners: a single-blinded randomized controlled trial.

INTRODUCTION AND HYPOTHESIS: We hypothesize that there will be improvement in a novice learners' confidence and skill level with sacrospinous ligament fixation (SSLF) following a pelvic model-based simulation. METHODS: We performed a single-blinded randomized controlled trial with obstetrics and gynecology residents who were novices at SSLF. The residents were randomly assigned to two groups. The control group received a lecture on the SSLF procedure and anatomy, whereas the intervention group received the same lecture in addition to a pelvic model-based simulation session taught by urogynecologists. The residents' knowledge of SSLF anatomy and confidence level with the procedure were measured via assessments administered before and after the educational interventions. Their technical skills were objectively assessed by one of two fellowship-trained urogynecologists who were blinded to their group allocation. RESULTS: A total of 28 residents were recruited with 14 residents in each group and equal distribution of junior and senior trainees. None of the residents had previously performed the SSLF procedure. There was no difference in anatomical knowledge between the two groups. The intervention group showed a greater increase in their average confidence score compared with the control group: 4.0 ± 1.4 (95% CI 3.1-4.8) versus 2.6 ± 1.6 (95% CI 1.7-3.4) respectively, with p = 0.02. The intervention group also showed better objective scores in specific technical skills, such as instrument handling (p < 0.001), instrument movement/motion (p < 0.001), and speed (p = 0.01). CONCLUSION: Our results demonstrate that inclusion of a pelvic model simulation significantly improves confidence and certain technical skills of novice trainees in performing SSLF.