Karen L. Stern

Dr. Karen L. Stern

orcid

Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2020 in Journal of Endourology
Verified
Journal Article
Closed access
KSKaren L. Stern
Karen L. Stern
NCNoah Canvasser
Noah Canvasser
MBMichael Borofsky
Michael Borofsky
VGVanessa M. Gleason
Vanessa M. Gleason
GKGuido Kamphuis
Guido Kamphuis
Kymora B. ScotlandKymora B. Scotland
Kymora B. Scotland
Introduction Kidney stones affect 1 in every 11 people in the United States each year. There is a significant high recurrence rate without a stone prevention protocol. Alkali citrate is beneficial in decreasing stone recurrence, but due to the cost and gastrointestinal side effects there is a low adherence rate. This study aims to serve as a review of some of the most commonly used alkalizing over- the- counter supplements that are advertised to prevent and treat kidney stones. Methods Data was gathered by a comprehensive online literature search and company inquiries for kidney stone prevention supplements. An additional informal poll of the authors selected supplements that are most commonly taken by their patients. A total of eight supplements were evaluated for cost, alkali equivalent provided, dosing and regulatory information. Results Eight of the most commonly used supplements were reviewed with a focus on alkalizing agents. Information reviewed revealed dosing recommendations resulting in decreased citrate alkali equivalents per day compared to prescription-strength potassium citrate. Cost, peer-reviewed study results and regulatory data were reviewed, tabulated and analyzed. Cost per alkali equivalent was substantially decreased for each supplement compared to the prescribed drug. All supplements were found to be readily available online. Conclusion Over- the- counter alkalizing agents are available to patients and may be an appropriate alternative to cost prohibitive potassium citrate when treating urolithiasis patients. Additional testing will be necessary in the future to determine the efficacy of these supplements in the treatment and prevention of urinary stone disease.

1 November 2023 in Journal of Endourology
Verified
Journal Article
Open access
KSKaren L. Stern
Karen L. Stern
BBBenjamin Joseph Borgert
Benjamin Joseph Borgert
JWJ. Stuart Wolf
J. Stuart Wolf
Background: The results of a recent pilot study suggest that steerable ureteroscopic renal evacuation (SURE) is safe and more effective in stone removal than basketing following laser lithotripsy. The objective of this retrospective study was to further assess the safety and efficacy of SURE using the CVAC ® Aspiration System (Calyxo, Inc., Pleasanton, CA) in patients with large stone burdens. Materials and Methods: Patients with a baseline stone burden of ≥10 mm who underwent SURE were identified. Subject demographics, secondary procedures, complications, and stone clearance (defined as percent baseline volume reduction) were evaluated. Subanalyses were performed to explore patients identified as high risk for percutaneous nephrolithotomy (PCNL) because (1) they were on anticoagulation or antiplatelet therapy at the time of procedure or (2) they had limited mobility due to neurologic conditions. Results: Identified patients ( N = 43) had a mean preoperative stone burden of 29 ± 12 mm and mean stone volume of 3092 ± 5002 mm 3 . Approximately one-half of patients ( n = 24, 55.8%) had CT imaging at follow-up, and of those, 8 (33.3%) had no residual stones, 22 (91.7%) had >90% stone clearance, 23 (95.8%) had >80% stone clearance, and 24 (100%) had >60% stone clearance. Stone clearance based on baseline stone burden varied between 93.8% and 98.9%. At baseline, 21 patients were anticipated to require staged ureteroscopy; however, only two of those (9.5%) needed secondary procedures. High-risk patients ( n = 22) were on anticoagulation or antiplatelet therapy ( n = 12) or had neurologic conditions ( n = 10). Stone clearance was 97% among patients in the anticoagulated cohort with postoperative CT imaging and 83% in the neurologic condition cohort. There were no device-related complications and no postoperative admissions. Conclusions: The CVAC Aspiration System is safe and effective for treating large stone burdens, including in high-risk patients, and may decrease the need for PCNL or secondary procedures. ClinicalTrials.gov Identifier: NCT04519294.

1 January 2025 in Journal of Endourology
Verified
Journal Article
Open access
BMBrian R. Matlaga
Brian R. Matlaga
TMThomas Mueller
Thomas Mueller
BJBrett Johnson
Brett Johnson
JPJay Page
Jay Page
JWJ. Stuart Wolf
J. Stuart Wolf
TCThomas Chi
Thomas Chi
Purpose: We report the first multicenter, prospective, randomized noninferiority controlled trial of steerable ureteroscopic renal evacuation (SURE) for nephrolithiasis treatment. Materials and Methods: Candidates for laser lithotripsy ≥18 years with ≥1 renal stone ≥7 mm and 7–20 mm stone burden were randomized 1:1 SURE vs ureteroscopy (URS). SURE was performed using the CVAC Aspiration System, a novel steerable irrigation–aspiration catheter. The primary efficacy end point was noninferiority in stone-free rate (SFR) based on zero residual fragments (RFs) 30 days postprocedure on noncontrast computed tomography. Secondary end points were superiority tests, stone clearance (percent stone volume reduction), residual stone volume (RSV), SFR (no RF >2 mm), and SFR (no RF >4 mm) 30 days postprocedure. Results: Of the subjects, 123 were randomized and 101 qualified for efficacy analysis (SURE 46 vs URS 55). Despite randomization, baseline URS stone volume was higher (SURE 485.0 ± 432.5 mm 3 vs URS 713.3 ± 558.5 mm 3 ). The primary noninferiority end point was achieved (SURE SFR 48% vs URS SFR 49%, p = 0.027, −1.3% [90% confidence interval; −18%, 15%]). Stone clearance was significantly higher for SURE vs URS subjects (SURE 96.9 ± 5.6% vs URS 92.9 ± 11.6%, p = 0.036); RSV was significantly lower (SURE 14.3 ± 3 0.9 mm 3 vs URS 70.2 ± 144.9 mm 3 , p = 0.012). SURE stone clearance and RSV were independent of baseline stone volume, but for URS degraded with increasing baseline stone volume. Safety was comparable between groups. Conclusions: SFR for SURE subjects was noninferior compared with URS subjects; stone clearance and RSV were significantly better with SURE, independent of baseline stone volume.

1 April 2023 in Journal of Urology
Verified
Journal Article
Closed access
GNGopal Narang
Gopal Narang
JMJonathan Moore
Jonathan Moore
KWKevin Wymer
Kevin Wymer
YCYu-Hui Chang
Yu-Hui Chang
ELElisabeth Lim
Elisabeth Lim
KSKaren L. Stern
Karen L. Stern
Post-ureteroscopy stent placement carries significant morbidity which can interfere with daily life. This discomfort unfortunately leads to high utilization of opioid pain medications, which have a known risk of addiction. Cannabidiol oil represents an alternative analgesic that has proven anti-inflammatory and antinociceptive effects. The purpose was to evaluate the effect of a Food and Drug Administration-approved cannabidiol oil (Epidiolex) on pain control and opioid usage in the post-ureteroscopy setting. This was a prospective, randomized, double-blind, placebo-controlled trial at a tertiary care center. Ninety patients undergoing ureteroscopy with stent placement for urinary stone disease were randomized 1:1 to placebo or 20 mg cannabidiol oil daily for 3 days postoperatively. Both groups were prescribed a rescue narcotic, tamsulosin, oxybutynin, and phenazopyridine. Daily pain scores, medication usage, and ureteral stent symptoms using the validated Ureteral Stent Symptom Questionnaire were recorded postoperatively. Both the placebo and cannabidiol oil groups were not different in pre- and perioperative characteristics. There was no difference in pain scores or opioid usage between groups postoperatively. The level of discomfort with ureteral stents was also not different between groups when comparing physical activity, sleep, urination, and activities of daily life. This randomized, blinded, placebo-controlled trial showed that cannabidiol oil is safe but ineffective when compared to placebo in reducing post-ureteroscopic stent discomfort or opioid usage. Despite the availability of numerous analgesic agents, stent symptoms continue to be a dissatisfier for most patients, suggesting additional work needs to focus on novel interventions and pain control.

21 January 2022 in World Journal of Urology
Verified
Journal Article
Closed access
PDF file
JMJonathan Moore
Jonathan Moore
ACAlexandra Chavez
Alexandra Chavez
GNGopal Narang
Gopal Narang
JBJamie M. Bogle
Jamie M. Bogle
KSKaren L. Stern
Karen L. Stern

15 April 2023 in Urolithiasis
Verified
Journal Article
Closed access
PDF file
KSKaren L. Stern
Karen L. Stern
RSRoger L. Sur
Roger L. Sur
ELElisabeth S. Lim
Elisabeth S. Lim
EKEmily Kong
Emily Kong
KWK. F. Victor Wong
K. F. Victor Wong
BCBen H. Chew
Ben H. Chew