Cumulative sum analysis of the learning curve for retrograde intrarenal stone surgery in newbie surgeons.

INTRODUCTION: This study investigated the learning curve of retrograde intrarenal surgery (RIRS) in patients with medium-sized stones using cumulative sum analysis (CUSUM) to evaluate the competence and proficiency of three new surgeons during their first RIRS procedures. MATERIALS AND METHODS: We conducted a retrospective review of 227 patients from 2019 to 2022 at a single institution. The patients were divided into four groups based on the operating surgeon: tutor surgeon (85 patients), newbie surgeon A (21 patients), newbie surgeon B (85 patients), and newbie surgeon C (36 patients). Patients had one or multiple stones with the largest stone diameter fell within the range of 10-30 mm. Fragmentation efficacy was calculated as "removed stone volume (mm3) divided by operative time (minutes)." CUSUM analysis monitored changes in fragmentation efficacy and validated surgical outcomes. RESULTS: No statistically significant differences were observed in the total stone volume, maximum stone size, or total operation time between the three newbie surgeons and the tutor surgeon. The mean fragmentation efficacy value was comparable among the newbie surgeons, but significantly different from that of the tutor surgeon. The minimum acceptable fragmentation efficacy level was set at 25.12 mL/min, based on the tutor's average value. The CUSUM curves for the three surgeons initially remained relatively flat until Cases 12-15, after which they increased and eventually plateaued. Stone-free rates and postoperative complications did not differ significantly among the surgeons. CONCLUSION: Learning curve analysis for the three newbie surgeons indicated that approximately 12-15 cases were required to reach a plateau.

Auditory brainstem responses to CE-Chirp® stimuli for normal ears and those with sensorineural hearing loss.

OBJECTIVE: Evaluation of the characteristic differences between click-and CE-Chirp-evoked auditory brainstem responses (ABRs) in normal hearing and sensorineural hearing loss. DESIGN: A prospective study. Ears with normal hearing and with sensorineural hearing loss were evaluated. Pure-tone audiometry and click-and CE-Chirp evoked ABRs exams were conducted for all ears. Visual detection levels, wave-V amplitudes, and latencies of the ABRs were assessed. STUDY SAMPLE: Twenty-two ears with normal hearing and 22 ears with sloping type sensorineural hearing loss were examined. RESULTS: In normal-hearing ears, mean amplitudes were larger for CE-chirps than for clicks at all intensities until 80 dB nHL, at which the amplitudes dropped off, presumably due to upward spread of excitation. In ears with sensorineural hearing loss, however the drop-off was less significant at 80 dB nHL. Comparisons with pure-tone audiometry findings revealed ABRs to CE-Chirps to correlate at 0.5, 1, 2, and 3 kHz, and to clicks at 1, 2, 3, and 4 kHz. CONCLUSIONS: The CE-Chirp has advantages over clicks for examining normal ears. However, under high-level stimulation, these advantages are no longer present. In ears with sensorineural hearing loss, the upward spread of excitation is less prominent. The CE-Chirps results correlate significantly to low frequency audiometric findings at 0.5 kHz, while clicks do not.

Analysis of p1 latency in normal hearing and profound sensorineural hearing loss.

OBJECTIVES: P1 is a robust positivity at a latency of 50-150 msec in the auditory evoked potential of young children. It has been reported that over the first 2-3 years of life, there is a rapid decrease of the latency and the mean P1 latency in adults with normal hearing is approximately 60 msec. This study was designed to evaluate the change of the P1 latency in Koreans with normal hearing according to age and to compare this with the P1 latency of young patients with profound sensorineural hearing loss before and/or after cochlear implantation. METHODS: Among the patients who visited the Department of Otorhinolaryngology at Seoul National University Hospital from June 2007 to September 2009, the P1 response was recorded in 53 patients in the normal hearing group, in 13 patients in the pre-cochlear implantation (CI) group and in 10 patients in the post-CI group. A synthesized consonant-vowel syllable /ba/ was used to elicit the evoked responses. The evoked responses were collected using the center of the frontal head. For each subject, an individual grand average waveform was computed by averaging the ten recordings. The P1 latency was visually identified as a robust positivity in the waveform. RESULTS: For the normal hearing group, the P1 latency showed the pattern of shortening as the age increased (coefficient, -0.758; P<0.001). For the pre-CI group, 10 cases showed delayed latencies and 3 cases did not show the P1 wave. For the post-CI group, the P1 latencies showed a less delayed tendency than those of the pre-CI group, but this was not statistically different. CONCLUSION: This report provides the standard value of the P1 latency at each age in Koreans for the first time and the findings support that the maturation of the central auditory pathways could be measured objectively using the P1 latency.