Patients and the ProPep Advantage
The Role of Somatic Nerves in Sexual Function & ContinenceIt is common knowledge that literature reports 22% – 38% of patients are impotent and 3% – 10% are incontinent at 12 months following “successful” nerve-sparing, robotic-assisted, radical prostatectomy [1]. It is also well known that nerve sparing (neurovascular bundle (NVB) sparing), as it is performed today, is primarily an autonomic nerve sparing surgical technique.What is less well known is the role somatic nerves play in sexual function and continence (see chart below). Specifically in regard to sexual function, it is typically not well understood is that penile erection is a two phase process – one parasympathetic nerve-mediated and one somatic nerve-mediated.
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Improving Potency with Nerve Mapping
Dr. Randy Fagin presentation at 2013 Prostate Cancer World Congress |
- The second or muscular phase is a somatic nerve-mediated event which involves the contraction of the bulbospongiosus and ischiocavernosus muscles which further compresses the deep dorsal vein of the penis and compresses the crux of the penis which together result in full tumescence and penile rigidity.
What is also not well understood is the fact that these critical somatic nerves, that lie outside the NVB, vary significantly in their course through the pelvis (see footnotes [2,3,4]). So much so that anatomical landmarks are not reliable in identifying where they are.
Muscles Innervated by the Perineal Nerve
MuscleBulbospongiosus
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Course & InsertionSurrounds lateral aspects of bulb of penis and most proximal part of body of penis, inserting into perineal membrane, dorsal aspect of corpora spongiosum and cavernosa, and fascia of bulb of penis.
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InnervationMuscular (deep) branch of perineal nerve, branch of pudendal nerve (S2–S4)
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Main Action(s)Compresses bulb of penis to expel last drops of urine/semen.
Assists erection by compressing outflow via deep dorsal vein and by pushing blood from bulb into body of penis. [5] |
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Ischiocavernosus
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Embraces crus of penis, inserting onto inferior and medial aspects of crus and to perineal membrane medial to crus.
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Muscular (deep) branch of perineal nerve, branch of pudendal nerve
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Maintains erection of penis by compressing deep dorsal vein and pushing blood from root of penis into body of penis.
Increases intracavernosal pressure 3 – 5 fold. Elevates penis past horizontal position and pulls penis against ischial tuberosity to assist vaginal penetration. [2,3] |
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External urethral sphincter
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Surrounds urethra superior to perineal membrane
Also ascends anterior aspect of prostate |
Muscular (deep) branch of perineal nerve, branch of pudendal nerve (S2–S4)
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Compresses urethra to maintain urinary continence.
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Levator ani
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Forms the main part of the pelvic diaphragm, the cranial layer of the pelvic floor.
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Perineal nerve; inferior rectal nerve, branches of pudendal nerve.
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Controls opening and closing of the levator hiatus. By this means, plays a crucial role in the preservation of urinary and bowel continence.
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How can the ProPep® Nerve Monitoring System help?
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Intraoperative Identification and Monitoring of the Somatic Nerves Critical to Potency Preservation during da Vinci Prostatectomy
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 essential in locating this nerve to avoid potentially damaging it during both pedicle and apical dissection.
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 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.pdf | |
| File Size: | 65 kb |
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Variability in Nerve Location During da Vinci® Prostatectomy
R. Kuhn
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.
R. Kuhn
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-kuhn.pdf | |
| File Size: | 189 kb |
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Surgeon perception is not a good predictor of peri-operative outcomes in robot-assisted radical prostatectomy
Joshua Stern, Saurabh Sharma, Pierre Mendoza, Mary Walicki, Rachel Hastings, Kelly Monahan, Baber Sheikh, Alexei Wedmid and David I. Lee
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_surgical_outcomes._lee.pdf | |
| File Size: | 123 kb |
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click to view larger version
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Results of Using a New Technology to Improve the Identification and Preservation of Nerve Tissue during Robotic-Assisted Laparoscopic Radical Prostatectomy | R. Kuhn
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.
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| results_of_using_a_new_technology_to_improve_-_aua_2013_presentation.pdf | |
| File Size: | 1310 kb |
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Pelvic Autonomic Nerve Mapping Around the Prostate by Intraoperative Electrical Stimulation With Simultaneous Measurement of Intracavernous and Intraurethral Pressure Atsushi Takenaka,* Ashutosh Tewari, Rouei Hara, Robert A. Leung, Kohei Kurokawa, Gen Murakami and Masato Fujisawa
| nerve_mapping_ash_tewari.pdf | |
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1 Coelho FR, Rocco B, Patel MB et al. Retropubic, laparoscopic, and robot-assisted radical prostatectomy: a critical review of outcomes reported by high-volume centers. J Endo Urol. 2010 Dec; 24:12: 2003 – 15.
2 Zvara P, Carrier S, Kour N-W, Tanagho EA. The detailed neuroanatomy of the human striated urethral sphincter. BJU. 1994; 74: 182 – 187.
3 Akita K, Sakamoto H, Sato T. Origins and courses of the nervous branches to the male urethral sphincter. Surg Radiol Anat. 2003; 25: 387 – 392
4 Schraffordt SE, Tjandra JJ, Eizenberg N, Dwyer PL. Anatomy of the pudendal nerve and its terminal branches: a cadaver study. ANZ J. Surg. 2004: 74: 23 – 265 Lavoisier P, Proulx J, Courtois F, De Carufel F, Durand L-G. Relationship between muscle contractions, penile tumescence, and penile rigidity during nocturnal erections. J Urol. 1988 Jan; 139: 176 -9.
2 Zvara P, Carrier S, Kour N-W, Tanagho EA. The detailed neuroanatomy of the human striated urethral sphincter. BJU. 1994; 74: 182 – 187.
3 Akita K, Sakamoto H, Sato T. Origins and courses of the nervous branches to the male urethral sphincter. Surg Radiol Anat. 2003; 25: 387 – 392
4 Schraffordt SE, Tjandra JJ, Eizenberg N, Dwyer PL. Anatomy of the pudendal nerve and its terminal branches: a cadaver study. ANZ J. Surg. 2004: 74: 23 – 265 Lavoisier P, Proulx J, Courtois F, De Carufel F, Durand L-G. Relationship between muscle contractions, penile tumescence, and penile rigidity during nocturnal erections. J Urol. 1988 Jan; 139: 176 -9.
Variability in Nerve Location During da Vinci Prostatectomy | R. Kuhn
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Abstract
Objectives 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.Methods 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 Download the entire paper below:
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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).
For more information about ProPep Surgical® products or questions regarding appropriate CPT codes for nerve monitoring using the ProPep® product, please contact us.
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