Focal Cryoablation of Image-Localized Prostate Cancer

Focal cryoablation of localized prostate cancer can offer patients superior genitourinary functional outcomes in terms of preservation of urinary continence and potency compared with radical whole-gland therapy, while maintaining intermediate-term oncologic control. We present a step-by-step guide to focal cryoablation of localized prostate cancer. A patient with elevated prostate specific antigen (PSA) underwent multiparametric MRI (mpMRI) of the prostate that revealed a prostate imaging-reporting and data system (PI-RADS) four lesion. The patient subsequently had a transrectal ultrasound (TRUS)-guided MRI fusion biopsy of the target lesion as well as a systematic biopsy and was only found to have Gleason 3 + 4 prostate cancer in the 0.5 cc mpMRI target. The lesion plus a treatment margin was ablated with cryotherapy utilizing a traditional transperineal approach. Patient position, ultrasound and mpMRI image fusion, insertion of cryoablation needles, ablation of the prostate cancer lesion, and postoperative care were reviewed. Equipment used during the operation was itemized and described. This guide explores the necessary equipment, procedural steps, and tips for success when performing focal cryoablation of the prostate. The technique described represents the culmination of knowledge gathered with 30 years of experience performing cryoablation of prostate cancer. The accompanying video highlights the utilization of mpMRI and TRUS image fusion, triangulation of lethal ice around the prostate cancer lesion, and the importance of monitoring real-time ice formation with TRUS imaging. Cryoablation of prostate cancer can be applied to several clinical scenarios: partial-gland ablation, quadrant, hemiablation, focal-targeted, or whole gland in the primary or salvage settings. We present the surgical steps that are essential for effective focal ablation of image-localized prostate cancer.

Timing of sacral neurostimulation is important for increasing bladder capacity in the anesthetized rat

We assessed the effects of limited application of sacral neurostimulation (SNS) during bladder filling on bladder capacity using our previously published SNS model in rats. Female Sprague-Dawley rats (n = 24) were urethane anesthetized (1.2 g/kg sc) and implanted with jugular venous and transvesical bladder catheters. L6/S1 nerve trunks were isolated bilaterally, and two electrodes were placed on each exposed nerve. True bladder capacity (TBC) was determined using stable single-fill cystometrograms. In the first series of experiments, SNS was applied at the onset of bladder filling for 25%, 50%, 75%, and 100% of the previous control filling cycle duration (n = 10). In the second series of experiments, SNS was applied during the first, second, third, and fourth 25% and the first and second 50% of the control fill. In the first series, a significant increase in TBC was observed only when SNS was applied for 75% or 100% of the control fill duration (30% and 35%, respectively, P < 0.05). In the second series, significant increases in TBC only occurred during the fourth 25% period and second 50% period (32% and 43%, respectively, P < 0.001). Results from the second series also revealed an increase in subsequent single-fill bladder capacities (TBC) only when SNS was applied during the second 50% of the prior fill cycle. These data indicate that the application of SNS during the final 50% of the bladder fill cycle is necessary and sufficient for increasing bladder capacity.