Preservation of nerves during da Vinci prostatectomy (dVP) has been clinically proven to be critical to preservation of urinary function and surgeon perception has been shown to be a poor predictor of nerve location during dVP. Despite this evidence, opinions still vary on the ability of surgeons to use anatomic landmarks to accurately identify these nerves during dVP and to predictably preserve urinary function.To explore the location of these critical nerves compared to anatomic landmarks and quantify the amount of variability, a single surgeon performed intraoperative nerve identification using the ProPep® Nerve Monitoring System on a series of consecutive patients undergoing dVP.
The ProPep® Nerve Monitoring System was used to identify the superficial portion of the perineal branch of the pudendal nerve (PBPN) in real time during dVP. The PBPN has been shown to innervate the levator ani (LA) and external urethral sphincter and to be a critical nerve in the maintenance of urinary continence. A low level electric current (0.5-10 milliamps) similar to that used for nerve identification in other surgical specialties was applied to the tissues during prostate dissection and the resulting waveforms allowed the surgeon to identify the exact location of the PBPN. The surgeon documented the location of the nerve relative to the prostate using a clock-face reference on both the right and left sides. The surgeon also documented the distance of the nerve from the prostate on both the right and left sides. Data was collected prospectively.Results
The ProPep® Nerve Monitoring System reliably identified the otherwise invisible PBPN with an evoked electromyographic (e-EMG) waveform in 100% of the patients. Using a clock-face reference with 12 o’clock being located at the most anterior aspect of the prostate, and 6 o’clock at the most posterior aspect, the nerve on the left side was located at 7:30 50% of the time, 8:00 25% of the time, 7:00 13% of the time, and 6:30 12% of the time. On the right side, the nerve was located at 4:30 50% of the time, 4:00 25% of the time, 5:00 13% of the time, and 5:30 12% of the time. Distance of the nerve from the prostate also varied with the nerve being located 3mm from the prostate 45% of the time, 2mm from the prostate 18% of the time, 4mm from the prostate 18% of the time, 8mm from the prostate 9.5% of the time, and 1mm from the prostate 9.5% of the time.Conclusions
The use of the ProPep® Nerve Monitoring System during dVP identified the otherwise invisible PBPN which innervates the pelvic floor in 100% of the cases. Both the nerve location relative to the prostate as well as the nerve distance from the prostate varied from case to case with the most common location occurring only 50% of the time. Given the importance of nerve preservation for urinary control recovery, the documented inability for surgeon perception to predict nerve location, and the documented variability of nerve location from case to case, the use of the ProPep® Nerve Monitoring System is an effective tool for improving the accuracy of nerve identification and could improve the preservation of these nerves and the clinical outcomes achieved by patients.
|Variability in Nerve Location|
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Using a clock-face reference with 12 o’clock being located at the most anterior aspect of the prostate, and 6 o’clock at the most posterior aspect, the nerve on the left side was located at 7:30 50% of the time, 8:00 25% of the time, 7:00 13% of the time, and 6:30 12% of the time (figure 4). On the right side, the nerve was located at 4:30 50% of the time, 4:00 25% of the time, 5:00 13% of the time, and 5:30 12% of the time (figure 5).
Distance of the nerve from the prostate also varied with the nerve being located 3mm from the prostate 45% of the time, 2mm from the prostate 18% of the time, 4mm from the prostate 18% of the time, 8mm from the prostate 9.5% of the time, and 1mm from the prostate 9.5% of the time (figure 6).
J Rasmussen, J Schneider
Nerve sparing during radical prostatectomy has traditionally focused on preservation of the parasympathetic nerves located within the NVB that are responsible for the vascular/filling phase of the erectile response. Studies have shown, however, that a somatic nerve (the muscular branch of the perineal nerve) not located within the NVB and found in variable locations around the apex of the prostate, drives the muscular phase of the erectile response. This nerve is responsible for the achievement of the full tumescence and rigidity needed for penetration. Using the ProPep® Nerve Monitoring Device, surgeons have demonstrated the ability to accurately, safely, and efficiently identify this critical nerve during RARP. It is the authors’ belief that the variability in the location of this critical somatic nerve, the resultant inability to predict its location based on anatomic landmarks, and the fact that it is located outside of the traditional NVB makes the use of the ProPep® Nerve Monitoring Device essential in locating this nerve to avoid potentially damaging it during both pedicle and apical dissection.
|Intraoperative Identification and Monitoring of Somatic Nerves_Single Pages_final|
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Joshua Stern, Saurabh Sharma, Pierre Mendoza, Mary Walicki, Rachel Hastings, Kelly Monahan, Baber Sheikh, Alexei Wedmid and David I. Lee
|Surgeon Perception is not a good predictor of peri-operative outcomes in RARP|
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Efforts to improve continence after robotic-assisted laparoscopic radical prostatectomy (RALRP) have focused on preserving periurethral and bladder neck tissue and techniques involving posterior reconstructions and anterior suspensions. Many patients, however, still have varying degrees of urinary incontinence. Literature has shown that nerves innervating the levator ani (LA) contribute to continence and anatomic landmarks are not accurate in determining their location. Inadvertent damage to these nerves may therefore contribute to post RALRP incontinence.
|Results of Using a New Technology to Improve AUA- 2013 presentation|
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Atsushi Takenaka, Ashutosh Tewari, Rouei Hara, Robert A. Leung, Kohei Kurokawa, Gen Murakami and Masato Fujisawa
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Fairleigh Reeves, Shane Battye, James F. Borin, Niall M. Corcoran, and Anthony J. Costello
Somatic nerves account for almost 5% of all nerve fibers in the periprostatic tissue. This study
found a mean somatic nerve count of 5.83, 5.25, and 3.67 at the level of the prostate base, midzone,
and apex, respectively. These nerves are most frequently located either anteriorly or in the region
of the neurovascular bundle (posterolateral).
|High-resolution Map of Somatic Periprostatic Nerves|
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