Sacral Neuromodulation Device Heating During Lumbar and Pelvic Magnetic Resonance Imaging-a Phantom Study.

OBJECTIVE: To evaluate radiofrequency-induced temperature rises associated with performing lumbar and pelvic magnetic resonance imaging (MRI) studies with an implanted sacral neuromodulation device using a phantom model. MATERIALS AND METHODS: An accepted phantom model of radiofrequency-induced heating in human tissue was used to measure the temperature rise in the stimulator lead electrodes and impulse generator under the conditions used during routine clinical lumbar and pelvic MRIs in a 1.5Tesla MRI scanner. Testing configurations included an intact device (tined lead connected to generator), an intact lead, and a lead fragment (model of lead fracture). Variations in the position of the phantom relative to the scanner were also tested. RESULTS: During testing with the intact device or the lead fragment no significant heating was detected. In contrast, the isolated intact lead model showed heating up to 5°C. CONCLUSION: These tests provide preliminary evidence that the risk of heating is low for clinical lumbar and pelvic MRI at 1.5-Tesla with an intact sacral neuromodulation device system and with a fractured lead. However, there is a significant temperature change in the intact lead model.

Real-Time Changes in Brain Activity during Sacral Neuromodulation for Overactive Bladder.

PURPOSE: We performed functional magnetic resonance imaging to identify changes in brain activity during sacral neuromodulation in women with overactive bladder who were responsive to therapy. MATERIALS AND METHODS: Women recruited into the study had nonneurogenic refractory overactive bladder, responded to sacral neuromodulation and had had a stable program for at least 3 months with no subsequent overactive bladder treatment. Enrolled patients completed validated symptom and quality of life instruments before functional magnetic resonance imaging. Stimulus settings were recorded, devices were switched off for a 5-day washout and instruments were repeated. Three functional magnetic resonance imaging scans with simultaneous sacral neuromodulation stimulation were performed below, at and above stimulus sensory threshold using a block design. This yielded brain activity maps represented by changes in blood oxygenation level dependence. A total of 5 stimulator off and 4 stimulator on cycles of 42 seconds each were imaged. Group analysis was done using a single voxel p value of 0.05 with a false-positive error of 0.05 on cluster analysis. RESULTS: Six of the 13 patients enrolled completed functional magnetic resonance imaging. Median age was 52 years (range 36 to 64). Urinary symptoms and voiding diary data worsened with washout. Overall brain activation generally progressed with increasing stimulation amplitude. However, activation of the right inferior frontal gyrus remained stable while deactivation of the pons and the periacqueductal gray matter only occurred with subsensory stimulation. Sensory stimulation activated the insula but deactivated the medial and superior parietal lobes. Suprasensory stimulation activated multiple structures and the expected S3 somatosensory region. All devices had normal impedance after functional magnetic resonance imaging. CONCLUSIONS: Functional magnetic resonance imaging confirmed that sacral neuromodulation influences brain activity in women with overactive bladder who responded to therapy. These changes varied with stimulus intensity.

Transabdominal sacrocolpopexy with autologous rectus fascia graft.

INTRODUCTION AND HYPOTHESIS: Extrusion and infection are potential postoperative complications when using synthetic mesh for abdominal sacrocolpopexy. Long-term follow-up in the Colpopexy and Urinary Reduction Efforts (CARE) trial revealed an estimated 9.9 % risk of mesh extrusion. There are 26 reports of spondylodiscitis after sacrocolpopexy with synthetic mesh. These surgical risks may be decreased by using autologous fascia. To date, there have been no reports of extrusion or spondylodiscitis after using autologous fascia for sacrocolpopexy. METHODS: This video demonstrates transabdominal sacrocolpopexy with an autologous rectus fascia graft. A 76-year-old woman with symptomatic stage 3 prolapse also had a history of diverticulitis and sigmoid abscess requiring sigmoid colectomy with end colostomy and incidental left ureteral transection with subsequent left nephrostomy tube placement. She presented for colostomy reversal, ureteral reimplantation, and prolapse repair. Given the need for concomitant colon and ureteral reconstruction, the risk of infection was potentially higher if synthetic mesh were used. The patient therefore underwent transabdominal sacrocolpopexy with autologous rectus fascia graft. RESULTS: At 4 months' follow-up the patient reported resolution of her symptoms and on examination she had no pelvic organ prolapse. CONCLUSION: Transabdominal sacrocolpopexy using autologous rectus fascia graft is a feasible option, especially in cases in which infection and synthetic mesh extrusion risks are potentially higher.

Urologic applications of botulinum toxin.

The neuromuscular blocker botulinum toxin has a wide variety of medical applications, including overactive bladder and neurogenic detrusor overactivity in patients in whom drug therapy fails or is not well tolerated. Botulinum toxin therapy for these conditions has been shown to be safe and effective in several large multicenter randomized controlled trials. Off-label uses in urology include detrusor external sphincter dyssynergia and pelvic pain syndromes.

Repair of complete urethral disruption due to synthetic sling complication.

INTRODUCTION AND HYPOTHESIS: Urethral complications due to synthetic midurethral slings are rare. Possible causes may include unrecognized trocar injury, mesh implantation despite recognized injury, mesh contamination leading to inflammation and delayed perforation, and excessive sling tension. There is no consensus as to the surgical management of urethral complications with regard to how much mesh should be excised, whether an interposition flap should be used, and whether a pubovaginal sling should be placed at the time of surgery. The purpose of this video is to present a technique of repairing complete urethral disruption due to a synthetic midurethral sling complication. METHODS: In this video, we demonstrate the steps to perform primary end-to-end urethral reconstruction for repairing complete urethral disruption. Any residual synthetic mesh must first be excised, after which the anastomosis may be completed. RESULTS: Complete urethral disruption is a rare complication of synthetic midurethral sling surgery that can be repaired primarily with good results. CONCLUSIONS: There is no consensus regarding surgical management of urethral complications caused by synthetic midurethral slings, and thus an individualized approach should be used based on patient presentation and surgeon expertise.

Construct validity of the LapSim virtual reality laparoscopic simulator within a urology residency program.

OBJECTIVE: : We assessed the construct validity of the LapSim laparoscopic surgical simulator in a urology residency training program. METHODS: : In total, 15 residents participated in the study between July 2007 and July 2008. The subjects were tested six times at one-month intervals on three skill tasks (lifting and grasping, cutting and clip application) using the LapSim laparoscopic simulator. The testing sessions were divided into the first three sessions (seminar 1), and the subsequent three sessions (seminar 2). We evaluated the following parameters: total time, path length, angular path length, tissue damage, maximum damage and stretch damage. The subjects were divided into junior (PGY 1,2) and senior resident groups (PGY 3,4,5). The Wilcoxon Signed-Rank test for paired samples was used to compare the performances of the juniors and seniors during seminar 1 to their performance in seminar 2 to determine whether there was improvement over time. The Wilcoxon Rank-Sum test for independent samples was used to compare the performance of the juniors to that of the seniors for seminar 1, seminar 2 and the combination of both seminars to determine whether the more experienced senior residents performed better than the less experienced juniors. RESULTS: : No significant performance improvement between testing sessions could be demonstrated. Similarly, there was no significant difference in performance between junior and senior residents. CONCLUSIONS: : Construct validity could not be demonstrated for the total time, path length, angular path length and tissue handling parameters of the LapSim laparoscopic surgical simulator when examined within the context of a urology residency program.

Ureteroscopy for transplant lithiasis.

BACKGROUND AND PURPOSE: The optimal management of renal and ureteral calculi in transplanted kidneys is not well defined. Although larger (>1.5 cm) stone burdens are generally treated with percutaneous nephrolithotomy (PCNL), smaller stones may be reasonably approached with retrograde or antegrade ureteroscopy (URS). We report our multicenter experience with URS for transplant lithiasis. PATIENTS AND METHODS: URS performed for stone disease within a transplanted kidney were retrospectively identified at three stone-referral centers between 2006 and 2011. Demographic and disease parameters were recorded, as were perioperative and postoperative details. RESULTS: Twelve patients underwent URS for a calculus in a transplant renal unit and/or ureter. For retrograde procedures (7), access to the ureteral orifice was facilitated by the use of a Kumpe catheter; a two-wire (safety and working guidewire) technique was used. For antegrade procedures (5), the ureteroscope was passed into the kidney using a two-wire technique without tract dilation. All stones but one necessitated holmium:yttrium-aluminum-garnet laser lithotripsy with extraction of stone fragments. All patients were stone free on postoperative imaging except for one patient with a 2-mm fragment that was observed. Stone analysis included calcium oxalate (6), calcium phosphate (4), and struvite (1). CONCLUSION: Antegrade and retrograde URS are safe and effective treatments for patients with simple stone burdens in a transplanted kidney. Although retrograde access to the ureter can be challenging, specialized techniques and modern endoscope technology facilitate this process. Antegrade URS for small stone burdens can be performed safely and effectively without tract dilation.