Joan S. Ko
Johns Hopkins University
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Featured researches published by Joan S. Ko.
BJUI | 2011
Joan S. Ko; Patricia Landis; H. Ballentine Carter; Alan W. Partin
Study Type – Diagnostic (exploratory cohort)
Current Urology Reports | 2014
Natasha Gupta; Joan S. Ko; Brian R. Matlaga; Ming Hsien Wang
The incidence of pediatric urolithiasis is increasing. While many smaller stones may pass spontaneously, surgical therapy is sometimes warranted. Surgical options include shock wave lithotripsy, ureteroscopy, percutaneous nephrolithotomy, and open surgery. Ureteroscopy represents a minimally invasive approach, and it is increasingly being used to treat pediatric upper tract calculi. Ureteroscopy is performed under anesthesia and fluoroscopic guidance, with basket extraction or lithotripsy of the calculi. Technical considerations include active or passive ureteral dilatation, the use of ureteral access sheaths for larger stone burdens, and post-operative stent placement. The current pediatric literature suggests high success rates (equal to or surpassing shock wave lithotripsy) and low complication rates. However, concerns remain regarding feasibility in patients with variant anatomies and risk due to intra-operative radiation exposure.
Journal of Pediatric Urology | 2014
Adam J M Kern; Brian M. Inouye; Joan S. Ko; Michael A. Gorin; Mohamad E. Allaf; Seth D. Goldstein; Heather N. DiCarlo; Bhavik B. Shah; Ming Hsien Wang
OBJECTIVE The present study is designed to assess the long-term renal function of children who underwent radical nephrectomy for unifocal Wilms tumor. METHODS A single institution retrospective cohort study of non-syndromic children treated with radical nephrectomy for unifocal Wilms tumor between 1995 and 2011 was performed to identify risk factors for decreased glomerular filtration rate (GFR). The primary endpoint was decrease in age-adjusted GFR below normal published ranges. The secondary endpoint was progression to chronic renal insufficiency (CRI). RESULTS A total of 55 patients were identified in the cohort. Eight (15%) patients exhibited decreased age-adjusted GFR during the follow-up period, with 2 (4%) progressing to CRI. Increasing time between surgery and the last known GFR follow-up was associated with decreased GFR, with the normal GFR group having median follow-up of 7.32 years versus 11.47 years (p = 0.019) in the decreased GFR group. CONCLUSIONS A trend toward decline in GFR was detected with longer follow-up. Longer follow-up may reveal that clinically significant decline in renal function occurs years following nephrectomy among a subset of Wilms tumor survivors, even among those who do not progress to end stage renal disease.
Journal of Pediatric Urology | 2018
William R. Boysen; Ardavan Akhavan; Joan S. Ko; Jonathan S. Ellison; Thomas S. Lendvay; Jonathan Huang; Michael Garcia-Roig; Andrew J. Kirsch; Chester J. Koh; Marion Schulte; Paul H. Noh; M. Francesca Monn; Benjamin Whittam; Trudy Kawal; Aseem R. Shukla; Arun K. Srinivasan; Mohan S. Gundeti
BACKGROUND Robot-assisted laparoscopic extravesical ureteral reimplantation (RALUR-EV) is a minimally invasive alternative to open surgery. We have previously reported retrospective outcomes from our study group, and herein provide an updated prospective analysis with a focus on success rate, surgical technique, and complications among surgeons who have overcome the initial learning curve. OBJECTIVE To assess the safety and efficacy of RALUR-EV in children, among experienced surgeons. DESIGN AND METHODS We reviewed our prospective database of children undergoing RALUR-EV by pediatric urologists at eight academic centers from 2015 to 2017. Radiographic success was defined as absence of vesicoureteral reflux (VUR) on postoperative voiding cystourethrogram. Complications were graded using the Clavien scale. Univariate regression analysis was performed to assess for association among various patient and technical factors and radiographic failure. RESULTS In total, 143 patients were treated with RALUR-EV for primary VUR (87 unilateral, 56 bilateral; 199 ureters). The majority of ureters (73.4%) had grade III or higher VUR preoperatively. Radiographic resolution was present in 93.8% of ureters, as shown in the summary table. Ureteral complications occurred in five ureters (2.5%) with mean follow-up of 7.4 months (SD 4.0). Transient urinary retention occurred in four patients following bilateral procedure (7.1%) and in no patients after unilateral. On univariate analysis, there were no patient or technical factors associated with increased odds of radiographic failure. DISCUSSION We report a radiographic success rate of 93.8% overall, and 94.1% among children with grades III-V VUR. In contemporary series, alternate management options such as endoscopic injection and open UR have reported radiographic success rates of 90% and 93.5% respectively. We were unable to identify specific patient or technical factors that influenced outcomes, although immeasurable factors such as tissue handling and intraoperative decision-making could not be assessed. Ureteral complications requiring operative intervention were rare and occurred with the same incidence reported in a large open series. Limitations include lack of long-term follow-up and absence of radiographic follow-up on a subset of patients. CONCLUSIONS Radiographic resolution of VUR following RALUR is on par with contemporary open series, and the incidence of ureteral complications is low. RALUR should be considered as one of several viable options for management of VUR in children.
Urology Practice | 2016
Joan S. Ko; Nathaniel Readal; Mark W. Ball; Misop Han; Phillip M. Pierorazio
Introduction In response to the 2011 Accreditation Council for Graduate Medical Education duty hour restrictions, many residency programs adopted a night float system. Due to concerns regarding the effects of night float on sleep and, subsequently, on patient care, we examined sleep patterns of residents on different call schedules. Methods Urology residents assigned to day shift (Monday to Friday, 6 am to 6 pm), night float (Sunday to Friday, 6 pm to 6 am) or 24‐hour home call as well as attending physicians were monitored for 2‐week periods using actigraphy bands. Total sleep time, light vs deep sleep time, sleep latency and number of sleep disruptions were measured. Comparative statistics and logistic regression were used to compare call systems and to determine predictors of sleep metrics. Results When comparing day shift, night float and 24‐hour home call, the only significant difference was in sleep latency. All sleep variables except sleep latency were significantly different among residents of various levels (junior, senior, research year). Compared to residents, attendings had a shorter sleep latency and were woken less frequently. Being a research year resident was the only significant univariate predictor of total sleep. Age and being a research year resident were significant univariate predictors of sleep latency. Conclusions This pilot study demonstrates the feasibility of actigraphy in measuring sleep patterns of urology house officers. It also suggests that night float does not significantly impact total sleep or quality of sleep. Further research is needed to confirm these findings, and to determine the effects of night float rotations on resident quality of life and patient safety.
Journal of Pediatric Urology | 2016
Jason E. Michaud; Joan S. Ko; Kathy Lue; Heather N. Di Carlo; Richard J. Redett; John P. Gearhart
PURPOSE The authors have reviewed the use of muscle pedicle flaps for the treatment of failed bladder neck closure in exstrophy spectrum patients. METHODS A retrospective review of all exstrophy spectrum patients who underwent continence procedures with the use of muscle pedicle flaps at our institution during the last 15 years was performed. Patient characteristics, surgical history, and outcomes, including complications, continence, morbidity, and infection, were assessed. The authors utilized muscle pedicle flaps in eight exstrophy patients, including four patients with classic bladder exstrophy and four patients with cloacal exstrophy. Seven of eight patients had failed at least one prior bladder neck closure, and they had undergone a median of three prior urologic procedures. To achieve continence, five rectus muscle flaps and three gracilis muscle flaps were utilized in combination with bladder neck closure. RESULTS There were no major intraoperative or postoperative complications. All patients were initially continent, and after a median follow-up of 18.7 months seven of eight patients were continent. One patient required continent urinary stoma revision and one patient developed perineal incontinence after perineal trauma. No patients required revision of, or additional, continence procedures at the bladder neck. DISCUSSION The use of pedicle muscle flaps appears to be a safe and feasible option for exstrophy spectrum patients with failed bladder neck closure. Although achieving continence can be difficult in this population, use of muscle flaps and bladder neck closure is a viable and effective option in this challenging subset of patients.
Journal of Pediatric Urology | 2014
Ali Tourchi; Brian M. Inouye; Heather N. Di Carlo; Ezekiel E. Young; Joan S. Ko; John P. Gearhart
The exstrophy-epispadias complex is a rare spectrum of anomalies affecting the genitourinary system, anterior abdominal wall, and pelvis. Recent advances in the repair of classic bladder exstrophy (CBE) and cloacal exstrophy (CE) have resulted in significant changes in outcomes of surgical management (including higher continence rate, fewer surgical complications, and better cosmesis) and health-related quality of life in these patients. These noteworthy changes resulted from advances in the pathophysiological and genetic backgrounds of this disease and better radiologic assessment of the three-dimensional anatomy of the bony pelvis and its musculature. A PubMed search was performed with the keyword exstrophy. The resulting literature pertaining to genetics, stem cells, imaging, tissue engineering, epidemiology, and endocrinology was reviewed. The following represents an overview of the advances in basic science understanding and imaging of the exstrophy-epispadias spectrum and discusses their possible and future effects on the management of CBE and CE.
Urology case reports | 2013
Joan S. Ko; Heather N. Di Carlo; Angela D. Gupta; Ashley E. Ross; Frederic E. Eckhauser; Trinity J. Bivalacqua
Bladder exstrophy is a rare birth defect that typically requires patients to undergo multiple surgical procedures throughout the course of their childhood. Many ultimately undergo operations that use segments of bowel for the reconstruction and/or augmentation of the urinary tract, which imparts an increased risk of malignancy in these patients. We present the case of a 59-year-old man with a history of bladder exstrophy managed with ureterosigmoidostomies revised to an ileal conduit who developed a large adenocarcinoma in the ileal conduit that extended into small bowel, sigmoid colon, and ureter.
Urology case reports | 2017
Arnav Srivastava; Joan S. Ko; Joy Ogunsile; Alison R. Moliterno; William H. Westra; Alice Semerjian
Testicular torsion, a urological emergency, occurs due to absence of testicular blood supply secondary to a mechanical twist of the spermatic cord. The authors describe a 28-year-old male who presented with torsion symptoms, first in the left testicle and four months later in the right testicle. Doppler ultrasound and surgical exploration revealed disruption of blood flow but no evidence of spermatic cord twisting. Additionally, physical examination findings at the time of presentation were inconsistent with testicular torsion. Hematologic workup revealed triple positive antiphospholipid syndrome as the cause of testicular ischemia. The patient was successfully treated with aspirin and therapeutic heparin.
Investigative and Clinical Urology | 2017
Mark W. Ball; Zeyad R. Schwen; Joan S. Ko; Alexa R. Meyer; George J. Netto; Arthur L. Burnett; Trinity J. Bivalacqua
Purpose To determine the impact of lymph node density (LND) on survival after inguinal lymph node dissection (ILND) for penile cancer. Materials and Methods Our institutional penile cancer database was queried for patients who underwent ILND. Clinicopathologic characteristics including LND and total number of positive lymph nodes (LNs) were analyzed to determine impact on recurrence-free survival (RFS) and overall survival (OS). LND, or the percent of positive LN out of total LN, was calculated as a categorical variable at varying thresholds. Results Twenty-eight patients with complete follow-up were identified. Indications for ILND were stage >T2 in 20 patients (71.4%), palpable adenopathy in 7 (25%), high grade T1 in 1 (3.6%). Median node yield was 17.5 (interquartile range, 12−22), and positive LNs were found in 14 patients (50%). RFS and OS were significantly lower for patients with >15% LN density (median RFS: 62 months vs. 6.3 months, p=0.0120; median OS: 73.6 months vs. 6.3 months, p<0.001). Controlling for age, medical comorbidities, number of positive LN, T stage, pelvic LN status and indication, LN density >15% was independently associated with worse RFS (hazard ratio [HR], 3.6; p=0.04) and OS (HR, 73.6; p=0.002). The c-index for LND was higher than total positive LNs for RFS (0.64 vs. 0.54) and OS (0.79 vs. 0.61). Conclusions In this small, retrospective penile cancer cohort, the presence of nodal involvement >15% was associated with decreased RFS and OS, and outperformed total number of positive LN as a prognostic indicator.