Proximity of percutaneous tibial nerve stimulation needle insertion to surrounding anatomic structures: a cadaveric study.

BACKGROUND: Percutaneous tibial nerve stimulation is a third-line treatment for overactive bladder and urgency urinary incontinence. During the procedure, a needle is inserted cephalad to the medial malleolus and posterior to the tibia. In recent years, permanent implants and leads have been developed for insertion into the medial ankle via a small incision. There are many important structures present in the medial compartment of the ankle, including the great saphenous vein, saphenous nerve, tibial nerve, posterior tibial vessels, and tendons of the posterior compartment leg muscles. OBJECTIVE: The primary objective of this study was to identify the proximity of the percutaneous tibial nerve stimulation needle placed per Food and Drug Administration-approved device instructions to nearby important anatomic structures. The secondary objectives were to identify the proximity of the tibial nerve to the needle site, identify clinically relevant ankle anatomic structures, and confirm the tibial nerve and posterior tibial vasculature by histologic analysis. STUDY DESIGN: Detailed medial ankle dissections were performed bilaterally on 10 female lightly embalmed anatomic donors (cadavers) obtained from the Willed Body Program at the University of Louisville. A pin was inserted at the percutaneous tibial nerve stimulation needle site, and the medial ankle was minimally dissected so the surrounding anatomic structures were visible but not disrupted. The shortest distance from the pin to the selected structures of the medial ankle region was measured. On completion of each dissection and set of measurements, tissue was harvested for histologic examination. The distances between the pin and each structure were assessed using means and standard deviations. A paired t test was used to assess the difference in the locations between the left and right ankles. Statistical analysis was performed on left-sided, right-sided, and combined measurements. An 80% prediction interval was found to represent the expected range of values for the measurement of a new cadaver or patient, and the 95% confidence interval of the mean was computed to characterize the average distance across all cadavers or patients. RESULTS: The medial ankle of 10 adult female lightly embalmed cadavers were examined bilaterally. Dissections were completed from October 2021 to July 2022. Of note, 80% prediction intervals for the tibial nerve, the posterior tibial artery or vein, and the flexor digitorum longus tendon had a lower range of 0.0 mm from the pin and extending to 12.1, 9.5, and 13.9 mm, respectively. Moreover, 2 of the structures were found to be asymmetrical between the right and left ankles. The great saphenous vein was further from the pin on the left (20.5 mm [standard deviation of 6.4 mm] on the left vs 18.1 mm [standard deviation of 5.3 mm] on the right; P=.04). The calcaneal (Achilles) tendon was further from the pin on the right side (13.2 mm [standard deviation of 6.8 mm] vs 7.9 mm [standard deviation of 6.7 mm]; P=.04). Tibial neurovascular structures were confirmed with microscopic analysis. CONCLUSION: The anatomic structures within the medial ankle lie unexpectedly close to the percutaneous tibial nerve stimulation needle site as noted per Food and Drug Administration-approved device instructions. There is a possibility that some medial ankle structures are not symmetrical. It is crucial that practitioners understand medial ankle anatomy when performing percutaneous tibial nerve stimulation or permanent device insertion.

Video Playback as an Educational Tool for Improving Resident Laparoscopic Performance: A Randomized Controlled Trial.

STUDY OBJECTIVE: In this single-masked randomized controlled study, we evaluate whether watching video recordings of oneself performing Fundamentals of Laparoscopic Skills (FLS) exercises results in an improvement on the 30-point Global Operative Assessment of Laparoscopic Skills (GOALS) assessment among Obstetrics and Gynecology (Ob/Gyn) residents. DESIGN: Twenty-three Ob/Gyn residents in the 2020-2021 academic year completed the FLS exercises while being timed, video recorded, and receiving real-time feedback from an Ob/Gyn faculty member. Baseline GOALS assessment was completed by participants and faculty. After the intervention, all participants then repeated the FLS exercises while being timed and were again scored using the GOALS assessment. Each participant completed the study in a single session. In addition, all participants completed a pre- and post-test survey. SETTING: University of Louisville Laparoscopic Skills Labortaory. PARTICIPANTS: University of Louisville Ob/Gyn residents in the 2020-2021 academic year. INTERVENTION: Twelve participants were randomized to the intervention and were allowed to watch their video recording in addition to receiving verbal feedback whereas the remaining 11 received verbal feedback only. MEASUREMENTS AND MAIN RESULTS: There were significant improvements in faculty (p <.01) and self-reported GOALS scores (p <.01) when comparing both the intervention and control group with baseline scores. The intervention group improved by 3.2 points more than that of the control group based on masked faculty evaluation (95% confidence interval, 1.4-5.0 points; p <.01). The difference was not significant in resident self-scores. Overall time improved for all participants (15:54 ± 0.21 minutes before and 13:13 ± 0.14 minutes after), but this difference was not significant between the 2 groups. Higher postgraduate year (PGY) residents reported significantly more comfort performing laparoscopic tasks, earned higher GOALS score (faculty and self-scores), and completed the first set of exercises in less time. A significant interaction between PGY and intervention was detected with improvement in GOALS score most strongly associated with PGY4 residents (p <.01). CONCLUSION: Although all learners objectively benefit from watching recordings of themselves performing surgical tasks, advanced learners may benefit the most when video recordings are used as an educational tool.