Hyungkeun Park

Quantitative analysis of gains and catch-up saccades of video-head-impulse testing by age in normal subjects.

To evaluate video‐head‐impulse test (vHIT) results in normal subjects, to determine the normative values of vHIT for the vestibulo‐ocular reflex (VOR) and to characterise the catch‐up saccades (CSs).

Management of recurrent urethral strictures with covered retrievable expandable nitinol stents: long-term results.

OBJECTIVE The purpose of this study was to evaluate the long-term clinical efficacy of temporary placement of covered retrievable stents in the management of recurrent urethral strictures. MATERIALS AND METHODS During the period December 1998-December 2005, 32 men and one adolescent boy (mean age, 48.6 years; range, 16-73 years) with recurrent urethral strictures underwent fluoroscopically guided insertion of a total of 68 stents. Patients without complications underwent elective stent removal 2 or 4 months after stent insertion. Rates of clinical success (long-term clinical and radiographic resolution of urethral strictures) were assessed. The Mann-Whitney U test was used to compare the duration of stent placement in patients with long-term clinical resolution with that in patients with stricture relapse. RESULTS Clinical success was achieved in 18 (55%) of the 33 patients. The mean duration of stent placement in patients with clinical success was significantly different from that in patients who had recurrences (p < 0.0001). Stricture relapse did not occur in only four (20%) of 20 cases of stent placement for 2 months. All 14 stent placements lasting at least 4 months resulted in long-term resolution after a mean follow-up period of 3.6 years. The most common complications necessitating early stent removal were stent migration (33.8% of stents) and tissue hyperplasia (20.6% of stents). CONCLUSION Placement of a covered retrievable stent for a minimum of 4 months is effective in inducing long-term resolution of refractory urethral strictures. Stent migration remains the largest obstacle in achieving adequate duration of stent placement.

Retrospective Comparison of Internally and Externally Covered Retrievable Stent Placement for Patients With Benign Urethral Strictures Caused by Traumatic Injury

OBJECTIVE The purpose of this article is to compare the clinical effectiveness and complications of externally and internally covered stents for the treatment of benign urethral strictures. MATERIALS AND METHODS From July 2002 to June 2010, 59 retrievable self-expandable polytetrafluoroethylene-covered nitinol stents were placed in 33 men with benign urethral strictures. These included 34 internally covered stents placed in 18 patients (group I) and 25 externally covered stents in 15 patients (group E). Stents were routinely removed 4 months after placement from patients who experienced no complications. Complications, duration of stent placement, removal techniques, and maintained patency rates were compared in the two groups. RESULTS Twenty-eight complications (82.4%) occurred in 15 patients in group I, whereas 12 complications (48%) occurred in six patients in group E (p=0.005). Three (16.7%) patients in group I and nine (60%) in group E had their stents electively removed without complications (p=0.010). Stent migration was more frequent in group I (47.1%) than in group E (24.0%). No tissue ingrowth was detected in group E, whereas six cases of tissue ingrowth occurred in group I (p=0.034). The standard technique was used more frequently in group E (70.8%). The median stent indwelling period was significantly shorter in group I than in group E (51.5 vs 114 days; p=0.34). CONCLUSION Despite their relatively high complication rates, externally covered stents are more effective with fewer complications than internally covered stents in the treatment of benign urethral strictures.

Results of video head impulse and caloric tests in 36 patients with vestibular migraine and 23 patients with vestibular neuritis: a preliminary report.

Abstract Caloric test has been used to probe the low-frequency range of lateral canal function and video head impulse test (vHIT) provides an objective measurement of the high-frequency range of canal function in vestibular disorders. Abnormal lateral canal function for high-frequency stimuli tested by vHIT was rare (8%) in vestibular migraine (VM), suggesting that there is a substantial remaining high-frequency canal function in VM. In vestibular neuritis (VN), caloric and vHIT responses are more frequently affected than VM, with a significant positive correlation between both tests. Caloric and vHIT probe different frequencies of head movement and provide complementary information regarding the lateral canal function. This article is protected by copyright. All rights reserved.

Vertical components of head-shaking nystagmus in vestibular neuritis, Meniere's disease and migrainous vertigo.

To describe vertical and horizontal components of head‐shaking nystagmus (HSN) in various vestibular disorders.

A comparative study of pediatric open pyeloplasty, laparoscopy-assisted extracorporeal pyeloplasty, and robot-assisted laparoscopic pyeloplasty

Purpose To compare the outcomes of open pyeloplasty (OP), laparoscopy-assisted extracorporeal (LEXP), and robotic-assisted laparoscopic pyeloplasty (RALP) for ureteropelvic junction obstruction in pediatric patients. Methods We retrospectively reviewed the age-matched cohort of 30 children who underwent OP, 30 who underwent LEXP, and 10 who underwent RALP at a single institution, from 1996 to 2014. Pre- and post-operative variables including success rate were compared among surgical groups. Results The mean age of the patients was 120.2 months, the Society for Fetal Urology grade was 3.6, the anteroposterior diameter was 3.1 cm, and the renal relative function was 44.0%. The distribution of laterality, mean body mass index, and preoperative anteroposterior pelvic diameter on ultrasound did not differ among groups. The mean length of hospital stay was significantly shorter in the RALP group (3.2 days) than in the OP (6.6 days) and LEXP (5.8 days) groups (p<0.001). The duration of analgesics use was shorter in the RALP group (1.1 days) than in the other groups (p<0.001). During the mean follow-up period of 49.0, 20.1, and 16.6 months, the success rate was 96.7%, 89.7%, and 100% in the OP, LEXP, and RALP groups, respectively, although this difference was not statistically different (p = 0.499). In multivariate regression analysis, the presence of crossing vessels was the only factor that decreased the success rate (hazard ratio: 46.09, 95% confidence interval: 2.41–879.6, p = 0.011). Conclusions Patients who undergo RALP have a reduced hospital stay and lower use of pain medication; however, there is no difference in the success rates for OP, LP, and RALP surgeries. The presence of crossing vessels is a negative prognostic indicator for surgical outcome regardless of the surgical method.

Characteristics and pathogenesis of facial nerve stimulation after cochlear implant surgeries: A single-centre retrospective analysis from 1151 patients

Incidence of facial nerve stimulation (FNS) was 2.8% (32 out of 1151) and higher in ears with cochlear anomaly (6.4%, 25 out of 391) than without cochlear anomaly (0.9%, 7 out of 760). FNS occurred at various current levels and locations of electrodes by different mechanisms related to incomplete insertion of electrodes, cochleo-facial dehiscence, and types of cochlear anomalies. FNS at apical electrodes related to cochleo-facial dehiscence with low current levels, and FNS at basal electrodes with high current levels and partial insertion of electrodes. FNS at most electrodes with high current levels was the most common type in patients with a common cavity or narrowing of the bony cochlear nerve canal. Understanding the mechanisms of FNS might provide insight for preventing FNS when performing CI surgeries. This article is protected by copyright. All rights reserved.