The Commonly Performed Nerve Sparing Total Prostatectomy Does Not Acknowledge the Actual Nerve Courses

Nerve Visualization using Phenoxazine-Based Near-Infrared Fluorophores to Guide Prostatectomy

Fluorescence-guided surgery (FGS) is poised to revolutionize surgical medicine through near-infrared (NIR) fluorophores for tissue- and disease-specific contrast. Clinical open and laparoscopic FGS vision systems operate nearly exclusively at NIR wavelengths. However, tissue-specific NIR contrast agents compatible with clinically available imaging systems are lacking, leaving nerve tissue identification during prostatectomy a persistent challenge. Here, it is shown that combining drug-like molecular design concepts and fluorophore chemistry enabled the production of a library of NIR phenoxazine-based fluorophores for intraoperative nerve-specific imaging. The lead candidate readily delineated prostatic nerves in the canine and iliac plexus in the swine using the clinical da Vinci Surgical System that has been popularized for minimally invasive prostatectomy procedures. These results demonstrate the feasibility of molecular engineering of NIR nerve-binding fluorophores for ready integration into the existing surgical workflow, paving the path for clinical translation to reduce morbidity from nerve injury for prostate cancer patients.

Analysis of a practical surgical skills laboratory for nerve sparing radical prostatectomy

PURPOSE

With the rapidly expanding anatomical and technical knowledge surrounding nervesparing radical prostatectomy (NSRP), anatomical and operative textbooks have failed to keep pace with the literature. A surgical skill laboratory (SSL) was designed to educate urology trainees on surgical anatomy and techniques for NSRP. The objective was to assess the validity of a SSL program.

METHODS

A low-fidelity, anatomically accurate prostate model with its appropriate fascial coverings and location of the neurovascular bundle was created. Participants were surveyed prior to a SSL workshop for their knowledge of NSRP focusing on clinical and anatomical considerations. An interactive 2-h tutorial and workshop was then undertaken outlining the clinical and anatomical nuances for NSRP, with participants then practising an intra and inter-fascial NSRP on the model. Participants were resurveyed immediately after the workshop and at 6 months.

RESULTS

Thirty participants completed the NSRP workshop. Significant differences (p < 0.0001) in anatomical and clinical knowledge were noted after the workshop with improvements for both junior and senior trainees. The knowledge was retained at 6 months following the workshop.

CONCLUSIONS

A low-fidelity bench-top model is a feasible and reproducible technique for improving the understanding of periprostatic anatomy and the different surgical approaches for NSRP. The SSL is useful and knowledge gained appears to be retained by workshop participants. SSL workshops are a valid hands-on approach to teaching surgical skills and should remain an integral part of urology training.

Coherent anti-Stokes Raman scattering rigid endoscope toward robot-assisted surgery

Label-free visualization of nerves and nervous plexuses will improve the preservation of neurological functions in nerve-sparing robot-assisted surgery. We have developed a coherent anti-Stokes Raman scattering (CARS) rigid endoscope to distinguish nerves from other tissues during surgery. The developed endoscope, which has a tube with a diameter of 12 mm and a length of 270 mm, achieved 0.91% image distortion and 8.6% non-uniformity of CARS intensity in the whole field of view (650 μm diameter). We demonstrated CARS imaging of a rat sciatic nerve and visualization of the fine structure of nerve fibers.

Cavernosal nerve preservation during robot-assisted radical prostatectomy is a graded rather than an all-or-none phenomenon: objective demonstration by assessment of residual nerve tissue on surgical specimens

OBJECTIVE

To demonstrate the existence of different degrees of nerve sparing (NS) (graded NS) by comparing the surgeon's intent of NS with the residual nerve tissue on prostatectomy specimens.

METHODS

We performed a prospective study of 133 consecutive patients who underwent robot-assisted radical prostatectomy in January and February of 2011. The surgeon graded the amount of NS intraoperatively independently for either side as follows: 1, no NS; 2, <50% NS; 3, 50% NS; 4, 75% NS; and 5, ≥ 95% NS. A pathologist who was unaware of the surgeon's score measured the area of residual nerve tissue on the posterolateral surface of the prostate.

RESULTS

A greater NS score correlated significantly with a decreasing area of residual nerve tissue on the prostatectomy specimens (P < .001). Overall, the area of residual nerve tissue on the prostatectomy specimens was significantly different among the NS groups (P < .001). On specific intergroup analysis, significant differences were found in the area of residual nerve tissue on the prostatectomy specimens between the greater NS groups: NS score 3 versus 4, median 13 mm(2) (interquartile range [IQR] 7-23) versus 3 mm(2) (IQR 0-8; P = .01); NS score 4 versus 5, median 3 mm(2) (IQR 0-8) versus 0.5 mm(2) (IQR 0-2; P = .001).

CONCLUSION

Subjective NS classification using the surgeon's intraoperative perception correlated significantly with the area of residual nerve tissue on the prostatectomy specimens determined by the pathologist. It is possible to intentionally tailor the amount of NS performed at surgery. This finding demonstrates that NS is a graded rather than an all-or-none phenomenon that can even go beyond the traditional concept of complete, partial, or no NS.

Advances in the study of the peripheral nervous system for erection in animals and humans

Introduction

Since Walsh first emphasized the importance of preserving the neurovascular bundle n to protect the cavernous nerve during pelvic surgery, patients' sexual life quality has dramatically improved. Today, nerve-sparing radical prostatectomy is the established gold standard for organ-confined prostate cancer patients. Recent technical advances in functional assessment such as intraoperative electrical stimulation have unveiled new anatomical features and physiological roles. Basic research has advanced understanding of cavernous nerve function, while molecular biology has uncovered the crucial role of neuronal nitric oxide in mediating erection, and has led to new treatments such as phosphodiesterase type-5 inhibitors. A recent focus in cavernous nerve research concerns the nerve distribution external to the neurovascular bundle. The cavernous nerves in humans appear to be distributed more widely beneath the lateral pelvic fascia than in other animals, and electrical stimulation studies suggest possible involvement of these nerves in erection. These findings have prompted new surgical techniques such as the "veil of Aphrodite", or "intrafascial nerve-sparing" procedures.

Materials and Methods

These recent anatomical and physiological studies in humans and animals and their impact are reviewed in this article.

Conclusions

Further investigation should stimulate future advances in strategies to preserve erectile function in RP patients.