John C Kefer

Lerner Research Institute, Cleveland, Ohio, United States

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Publications (14)23.13 Total impact

  • Journal of Urology - J UROL. 01/2009; 181(4):737-737.
  • Journal of Urology - J UROL. 01/2009; 181(4):551-551.
  • Journal of Urology - J UROL. 01/2009; 181(4):737-737.
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    ABSTRACT: We assessed the safety and efficacy of percutaneous nephrostolithotomy in patients requiring long-term anticoagulant therapy. We reviewed the records of 792 patients undergoing percutaneous nephrostolithotomy at our institution from 2000 to 2007, and identified 27 on anticoagulation therapy (warfarin, clopidogrel or cilostazol) who underwent surgery after perioperative reversal and reinitiation of anticoagulation. Warfarin was withheld 5 days preoperatively with enoxaparin bridging and resumed 5 days postoperatively. Clopidogrel and cilostazol were stopped 10 days preoperatively and resumed 5 days postoperatively. We subsequently analyzed changes in preoperative and postoperative hemoglobin, serum creatinine and clotting parameters, as well as intraoperative and postoperative bleeding or thromboembolic complications. Overall the stone-free rate with percutaneous nephrostolithotomy monotherapy was 93% (25 of 27 patients). A second look procedure was required in 5 patients and a third procedure was required in 1. Mean hemoglobin decrease was 1.5 gm/dl (range 0 to 4.1) and mean change in serum creatinine was 0.03 mg/dl (range 0 to 0.4). Two patients (7%) had significant bleeding and 1 (4%) had a thromboembolic complication. All complications were successfully managed conservatively or in a minimally invasive manner. All patients were stone-free at 1-month followup. With careful perioperative regulation of anticoagulation therapy and clotting parameters, percutaneous nephrostolithotomy can be performed safely and efficiently in properly selected patients requiring long-term anticoagulation.
    The Journal of urology 12/2008; 181(1):144-8. · 4.02 Impact Factor
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    ABSTRACT: We examined the long-term effects of pubo-urethral ligament deficiency as a potential model of stress urinary incontinence compared to an established model of stress urinary incontinence. A total of 21 female Sprague-Dawley rats were randomly assigned to 1 of 3 groups, including pubo-urethral ligament transection, sham pubo-urethral ligament transection and bilateral pudendal nerve transection. Leak point pressure was measured 28 days later via an implanted suprapubic catheter. After leak point pressure measurement all animals were sacrificed. The pubic arch and pelvic organs were harvested for histological examination. The Wilcoxon rank sum test was used to evaluate differences in leak point pressure among the experimental groups. At 28 days after pubo-urethral ligament transection mean +/- SD leak point pressure was significantly decreased when comparing pubo-urethral ligament transection and pudendal nerve transection to sham treatment (15.75 +/- 6.46 and 15.10 +/- 4.98 cm H(2)O, respectively, vs 42.56 +/- 11.58, p <0.001). No difference was noted when comparing pubo-urethral ligament transection to pudendal nerve transection (p = 0.76), indicating the long-term durability of pubo-urethral ligament transection on inducing stress urinary incontinence in the female rat. Histological examination of en bloc suprapubic areas demonstrated an absent pubo-urethral ligament in the pubo-urethral ligament transection group, and an intact pubo-urethral ligament in the sham treated and pudendal nerve transection groups. Our results show that pubo-urethral ligament deficiency in the female rat induces long-term stress urinary incontinence that is comparable to that in the established stress urinary incontinence model via pudendal nerve transection. Our novel rat model could be used to investigate mechanisms of stress urinary incontinence in females, including the role of urethral hypermobility and potential therapeutic interventions for stress urinary incontinence.
    The Journal of urology 12/2008; 181(1):397-400. · 4.02 Impact Factor
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    ABSTRACT: We report our experience with patients requiring long-term anticoagulation therapy who underwent open or laparoscopic partial nephrectomy for renal tumors at our institution. We compared outcomes with those in a control group undergoing partial nephrectomy with no anticoagulation requirements. We retrospectively reviewed the records of 1,031 patients who underwent laparoscopic or open partial nephrectomy from 2000 to 2005. Since 2000, 31 open and 16 laparoscopic partial nephrectomies were performed in patients on chronic warfarin, clopidogrel or cilostazol. Anticoagulation was appropriately discontinued perioperatively. The 47 anticoagulated cases were compared with 47 nonanticoagulated controls that were carefully matched for surgical approach, partial nephrectomy defect size, tumor size and location, procedure year and warm ischemia time. Investigators were blinded to all clinical outcomes throughout the matching process. Bleeding and thrombotic outcomes were then analyzed. The 2 groups were well matched for resection bed size, tumor size, tumor location (central vs peripheral), solitary kidney, operative time and warm ischemia time (each p >or=0.3). Controls had significantly higher intraoperative blood loss (300 vs 200, p <0.05) and a greater postoperative decrease in hemoglobin (3.5 vs 2.4 mg/dl, p <0.001). However, transfusion rates were similar in the 2 groups (each 15%). Five patients on anticoagulation had thrombotic events postoperatively vs none in the control group. Patients on anticoagulation are at higher perioperative risk but with careful perioperative management of anticoagulation therapy partial nephrectomy can be performed in a safe and efficacious manner. To our knowledge this is the largest study of outcomes in this complex patient population.
    The Journal of urology 10/2008; 180(6):2370-4; discussion 2734. · 4.02 Impact Factor
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    ABSTRACT: We compared perioperative outcomes in patients undergoing ureterorenoscopy and Ho:YAG lithotripsy for renal calculi with or without anticoagulation. We reviewed the records of all patients undergoing flexible ureterorenoscopy and Ho:YAG lithotripsy for renal calculi at 2 institutions from 2001 to 2007. We identified 37 patients on anticoagulation with Coumadin, clopidogrel or aspirin in whom anticoagulation therapy was not discontinued before surgery. Data on the anticoagulation group were retrospectively compared to those on a contemporary matched cohort of 37 controls without anticoagulation who underwent a similar operative procedure. The 2 groups were compared with regard to the stone-free rate, and intraoperative and postoperative complications with specific reference to bleeding and thromboembolism. The 2 groups were matched for stone size, stone location, number of stones, bilateral procedures and concomitant ureteral stones. Anticoagulation group patients were older (58.2 vs 50.4 years, p = 0.0209) and had a greater American Society of Anesthesiologists score (2.8 vs 1.9, p <0.0001) compared to the control group. No procedure had to be terminated in the anticoagulation group due to poor visibility from bleeding. The median postoperative hemoglobin decrease was greater in the anticoagulation group than in the control group (0.6 vs 0.2 gm/dl, p <0.0001). The stone-free rate (81.1% vs 78.4%, p = 0.7725), intraoperative complications (0% vs 3%, p = 0.3140), postoperative complications (11% vs 5%, p = 0.3943) and hemorrhagic or thromboembolic adverse events were comparable in the 2 groups. When necessary, ureterorenoscopy and Ho:YAG lithotripsy can be performed safely and efficaciously for renal calculi in patients on anticoagulation therapy without the need for perioperative manipulation.
    The Journal of urology 04/2008; 179(4):1415-9. · 4.02 Impact Factor
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    ABSTRACT: We hypothesized that transection of the pubo-urethral ligament in the female rat would cause stress urinary incontinence, as indicated by decreased leak point pressure. We created a novel model of pubo-urethral ligament deficiency in the rat and validated our model through comparison with an established model of stress urinary incontinence. A total of 21 female age matched Sprague-Dawley rats (Harlan, Indianapolis, Indiana) were randomly assigned to 5 groups, including pubo-urethral ligament transection or sham pubo-urethral ligament transection with leak point pressure measured 4 days (groups 1 and 2) or 10 days (groups 3 and 4) postoperatively and bilateral pudendal nerve transection with leak point pressure measured 4 days postoperatively (group 5). Leak point pressure was measured in all groups via a suprapubic catheter. The Wilcoxon signed rank test was used to evaluate differences between the groups. Leak point pressure was significantly decreased in the pubo-urethral ligament transection groups compared to that in the sham treated groups after 4 days (mean +/- SEM 16.3 cm +/-2.74 vs 36.6 +/- 8.39 cm H(2)O, p <0.00001), although it was no different from that in the pudendal nerve transection group (14.5 +/- 1.06 cm H(2)O, p <0.44). Ten days after surgery leak point pressure remained significantly lower in the pubo-urethral ligament transection groups compared to that in the sham treated groups (17.6 +/- 6.36 vs 31.2 +/- 5.14 cm H(2)O, p <0.00001), indicating the durability of pubo-urethral ligament transection for inducing stress urinary incontinence in female rats. Our results demonstrate that deficiency of the pubo-urethral ligament in the female rat induces stress urinary incontinence comparable to that in a previously established model of pudendal nerve transection induced stress urinary incontinence. This novel rat model could be used to investigate the mechanisms of urethral hypermobility in female stress urinary incontinence or potential therapeutic interventions for stress urinary incontinence.
    The Journal of urology 02/2008; 179(2):775-8. · 4.02 Impact Factor
  • Journal of Urology - J UROL. 01/2008; 179(4):364-364.
  • Journal of Urology - J UROL. 01/2008; 179(4):283-283.
  • Journal of Urology - J UROL. 01/2008; 179(4):540-540.
  • Journal of Urology - J UROL. 01/2008; 179(4):433-433.
  • Journal of Urology - J UROL. 01/2008; 179(4):282-283.
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    ABSTRACT: To assess the management of advanced pelvic organ prolapse (POP) with robotic-assisted abdominal sacrocolpopexy (RASC) and evaluate outcomes using the POP quantification scale (POP-Q). Women with symptomatic stages III and IV POP were evaluated at our institution. After complete clinical assessment, including POP-Q-based physical examination and urodynamic studies, the patients underwent RASC with or without anti-incontinence surgery in the presence (sacrouteropexy) or absence of uterus (sacrocolpopexy). Follow-up examinations at 3 and 6 months included a POP-Q-based examination. Fifteen women were consented for RASC; 12 underwent successful RASC, one required conversion to laparoscopic ASC, one to open ASC, and one to transvaginal repair. The mean (range) patient age was 64 (50-79) years. Before surgery, the mean POP-Q stage was 3.1 (3-4) and the POP-Q values for the anterior (Aa, Ba), posterior (Ap, Bp) and apex (C) of the vagina were: Aa - 0.9, Ba + 1.0, Ap - 1.0, Bp + 1.3, and C +2.1. After surgery, the mean POP-Q stage was 0 and the POP-Q values had improved to Aa - 2.29, Ba - 2.29, Ap - 2.65, Bp - 2.65, and C - 8.28. The mean (range) estimated blood loss during surgery was 81 (50-150) mL. The mean hospital stay was 2.4 (1-7) days. Seven patients had concurrent placement of a mid-urethral sling and one patient had a concurrent Burch colposuspension. These early results show that RASC is safe and efficacious, and that its anatomical outcomes compare favourably to the reported results for open or laparoscopic ASC.
    BJU International 11/2007; 100(4):875-9. · 3.05 Impact Factor