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Purpose: Energy sources used during nerve sparing radical prostatectomy are known to compromise cavernous nerve function. Lasers offer the potential for accurate dissection while minimizing collateral injury to delicate neural structures. We evaluated cavernous nerve function following KTP laser dissection and compared outcomes to those of ultrasonic shears and cold scissor dissection. Materials and Methods: Laparoscopic unilateral neurovascular bundle mobilization was performed in 36 survival dogs using a KTP laser, ultrasonic shears and an athermal technique with cold scissors and clips in 12 each. Peak intracavernous pressure upon cavernous nerve stimulation, expressed as a percent of mean arterial pressure, was measured acutely and at 1 month. Thermal spread from the KTP laser and ultrasonic shears was assessed histologically ex vivo in harvested peritoneum. Results: Median peak intracavernous pressure as a percent of mean arterial pressure was similar immediately and 1 month after laser and athermal dissection, and significantly decreased after dissection with ultrasonic shears. Acute peak intracavernous pressure as a percent of mean arterial pressure was 53%, 96% and 98% for ultrasonic shears, laser and the athermal technique, respectively (laser vs athermal p = 0.51, ultrasonic shears vs laser p <0.001 and ultrasonic shears vs athermal p <0.001). Chronic peak intracavernous pressure as a percent of mean arterial pressure was 56%, 98% and 100% for ultrasonic shears, laser and the athermal technique, respectively (laser vs athermal p = 0.38, ultrasonic shears vs laser p = 0.016 and ultrasonic shears vs athermal p = 0.013). The median depth of acute laser injury was 600 μm compared to 1.2 mm for ultrasonic shear dissection and 450 μm crush injury due to the athermal technique. Thermography revealed less collateral thermal spread from the laser than from the ultrasonic shears (median greater than 60C thermal spread 1.07 vs 6.42 mm, p <0.01). Conclusions: The KTP laser was comparable to the athermal technique and superior to the ultrasonic shears for preserving cavernous nerve function. [Copyright &y& Elsevier]

OBJECTIVES To examine the feasibility of using laser energy during nerve-sparing robotically assisted radical prostatectomy (RARP), as the energy sources currently used for haemostasis in RARP adversely affect cavernous nerve function, while clips require application by a skilled assistant, but laser energy potentially allows precise dissection with minimal collateral tissue injury. MATERIALS AND METHODS We used laser-based RARP in 10 dogs, using the da Vinci S system (Intuitive Surgical, Sunnyvale, CA, USA) and a prototype robotic laser instrument. The potassium-titanyl-phosphate laser was used for dissection at 2–6 W, with intermittent use of the neodymium-doped yttrium-aluminium-garnet laser at 5 W for coagulating larger vessels. The peak intracavernosal pressure response to nerve stimulation was recorded as a percentage of mean arterial pressure (ICP%MAP) before and after RARP. Five dogs were killed immediately after RARP and five were maintained alive for 72 h; the haemoglobin and haematocrit levels were measured before and after RARP in the latter five dogs. RESULTS All 10 procedures were performed solely using laser energy and no additional haemostatic manoeuvres. The median prostate excision time was 65 min. The ICP%MAP before and after RARP (median 98.5% and 77.0%, P = 0.12) were not significantly different; similarly, the respective haemoglobin (median 14.4 vs 12.6 g/dL, P = 0.06) and haematocrit levels (45.1% vs 40.2%, P = 0.06) were not significantly different. Two dogs had catheter-related complications and one had an anastomotic leak. There were no laser-related complications or postoperative haemorrhage. CONCLUSIONS Laser RARP is feasible in dogs and further assessment is warranted. [ABSTRACT FROM AUTHOR]

Purpose: Although the dog is often used as a radical prostatectomy model, precise descriptions of canine prostate and neurovascular bundle anatomy are lacking. We describe canine prostate and neurovascular bundle anatomical and electrophysiological characteristics. Materials and Methods: The canine prostate and pelvic neurovascular structures were dissected in 6 canine cadavers and 12 anesthetized dogs. Pelvic plexus branches were stimulated using a CaverMap® probe and peak intracavernous pressure responses were recorded as a percent of mean arterial pressure. Results: The canine pelvic plexus lies 5 to 10 mm lateral to the prostate. It is supplied by the hypogastric nerve cranially and the pelvic nerve laterally. The neurovascular bundles course distal from the pelvic plexus along the posterolateral aspect of the prostate, including a dominant cavernous nerve along its lateral aspect. CaverMap stimulation of the efferent branches of the pelvic plexus confirmed their roles in tumescence. Histology revealed extensive neurovascular tissue along the posterolateral aspect of the prostate beneath the periprostatic fascia. Notable differences to human anatomy were the absence of seminal vesicles, the lateral positions of the pelvic plexus, the dominant cavernous nerve and the circumferential urethral distribution of the cavernous nerves. Conclusions: Canine neurovascular anatomy resembles that of humans and it is a suitable model in which to assess prostatectomy related erectile dysfunction. However, there are key differences in neurovascular relationships that must be considered when the canine prostate is used as a radical prostatectomy model. [Copyright &y& Elsevier]