A comprehensive review of neuroanatomy of the prostate

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.

Surgical techniques to preserve continence after robot-assisted radical prostatectomy

Radical prostatectomy significantly impacts the inherent anatomy of the male pelvis and the functional mechanisms of urinary continence. Incontinence has a considerable negative influence on the quality of life of patients, as well as their social and psychological wellbeing. Numerous surgical techniques have been demonstrated to support the preservation of continence during robot-assisted radical prostatectomy (RARP). In this in-depth analysis, we give a general summary of the surgical techniques used in RARP and their impact on incontinence rates.

Local Staging of Prostate Cancer at MRI: What the Urologist and Radiation Oncologist Want to Know

This slide presentation provides an overview of prostate cancer risk stratification and management, reviews key anatomic and imaging principles pertaining to local staging of prostate cancer, and highlights inflection points where MRI findings regarding local staging may modify clinical management.

Neuropeptide Y and its receptors in prostate cancer: associations with cancer invasiveness and perineural spread

PURPOSE

Neuropeptide Y (NPY) is a pleiotropic peptide, which is involved in many biological mechanisms important in regulation of cell growth and survival. The aim of this study was a comprehensive analysis of the NPY system in prostate pathology.

METHODS

The study was based on immunohistochemical analysis of NPY and its receptors, Y1R, Y2R and Y5R, in tissue samples from benign prostate (BP), primary prostate cancer (PCa) and PCa bone metastases. Tissue microarray (TMA) technique was employed, with analysis of multiple cores from each specimen. Intensity of the immunoreactivity and expression index (EI), as well as distribution of the immunostaining in neoplastic cells and stromal elements were evaluated. Perineural invasion (PNI) and extraprostatic extension (EPE) were areas of special interests. Moreover, a transwell migration assay on the LNCaP PCa cell line was used to assess the chemotactic properties of NPY.

RESULTS

Morphological analysis revealed homogeneous membrane and cytoplasmic pattern of NPY staining in cancer cells and its membrane localization with apical accentuation in BP glands. All elements of the NPY system were upregulated in pre-invasive prostate intraepithelial neoplasia, PCa and metastases. EI and staining intensity of NPY receptors were significantly higher in PCa then in BP with correlation between Y2R and Y5R. The strength of expression of the NPY system was further increased in the PNI and EPE areas. In bone metastases, Y1R and Y5R presented high expression scores.

CONCLUSION

The results of our study suggest that the NPY system is involved in PCa, starting from early stages of its development to disseminated states of the disease, and participates in the invasion of PCa into the auto and paracrine matter.

Perineural Invasion and Spread in Common Abdominopelvic Diseases: Imaging Diagnosis and Clinical Significance

Malignancies and other diseases may spread by multiple pathways, including direct extension, hematogenous spread, or via lymphatic vessels. A less-well-understood route is the peripheral nervous system, which is known as perineural spread (PNS). In addition to accounting for pain and other neurologic symptoms, PNS affects both disease prognosis and management. Although PNS is commonly discussed in relation to head and neck tumors, there is emerging data regarding PNS in abdominopelvic malignancies and other conditions such as endometriosis. Due to improved contrast and spatial resolution, perineural invasion, a finding heretofore diagnosed only at pathologic examination, can be detected at CT, MRI, and PET/CT. PNS most commonly manifests as abnormal soft-tissue attenuation extending along neural structures, and diagnosis of it is aided by optimizing imaging parameters, understanding pertinent anatomy, and becoming familiar with the typical neural pathways of spread that largely depend on the disease type and location. In the abdomen, the celiac plexus is a central structure that innervates the major abdominal organs and is the principal route of PNS in patients with pancreatic and biliary carcinomas. In the pelvis, the lumbosacral plexus and inferior hypogastric plexus are the central structures and principal routes of PNS in patients with pelvic malignancies. Although the imaging findings of PNS may be subtle, a radiologic diagnosis can have a substantial effect on patient care. Knowledge of anatomy and known routes of PNS and optimizing imaging parameters is of utmost importance in providing key information for prognosis and treatment planning. © RSNA, 2023 Supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. Quiz questions for this article are available through the Online Learning Center.

Loss of the Sympathetic Signal Produces Sterile Inflammation of the Prostate

Neural innervations exert essential roles in the prostate. However, spatial distribution and regulatory function of such neural inputs are incompletely characterized. Here, we exploited the advanced whole-tissue immunolabeling and optical clearing technique to assess the 3D anatomy of autonomic innervations in the mouse and human prostate for the first time. We observed that sympathetic and parasympathetic inputs in the mouse prostate remained unaffected during castration-induced tissue regression. However, the pharmacologic destruction of sympathetic innervations in the mouse prostate led to sterile inflammation of the tissue, mimicking the disease condition of chronic non-bacterial prostatitis. Also, the genetic ablation of sympathetic inputs produced a similar inflammatory response. Furthermore, we showed that treatment of the specific β2-adrenergic receptor agonists could effectively mitigate the prostate inflammation caused by such sympathetic loss. Together, these results have elucidated the new immunomodulatory function of the sympathetic signal via the β2-adrenergic receptor in prostate inflammatory disease.

International Continence Society (ICS) report on the terminology for sexual health in men with lower urinary tract (LUT) and pelvic floor (PF) dysfunction

INTRODUCTION

The terminology for sexual health in men with lower urinary tract (LUT) and pelvic floor (PF) dysfunction has not been defined and organized into a clinically based consensus terminology report. The aim of this terminology report is to provide a definitional document within this context that will assist clinical practice and research.

METHODS

This report combines the input of the members of sexual health in men with LUT and PF Dysfunction working group of the International Continence Society (ICS), assisted at intervals by external referees. Appropriate core clinical categories and a sub-classification were developed to give coding to definitions. An extensive process of 18 rounds of internal and external review was involved to exhaustively examine each definition, with decision-making by collective opinion (consensus). The Committee retained evidence-based definitions, identified gaps, and updated or discarded outdated definitions. Expert opinions were used when evidence was insufficient or absent.

RESULTS

A terminology report for sexual health in men with LUT and PF dysfunction, encompassing 198 (178 NEW) separate definitions, has been developed. It is clinically based with the most common diagnoses defined. Clarity and user-friendliness have been key aims to make it interpretable by practitioners and trainees in all the different speciality groups involved. Conservative and surgical managements are major additions and appropriate figures have been included to supplement and clarify the text. Emerging concepts and measurements, in use in the literature and offering further research potential, but requiring further validation, have been included as an appendix. Interval (5-10 years) review is anticipated to keep the document updated.

CONCLUSION

A consensus-based terminology report for sexual health in men with LUT and PF dysfunction has been produced to aid clinical practice and research. The definitions that have been adopted are those that are most strongly supported by the literature at this time or are considered clinical principles or consensus of experts' opinions.

Systematic review comparing Anterior vs Retzius-sparing robotic assisted radical prostatectomy: can the approach really make a difference?

INTRODUCTION

Retzius-Sparing Robotic Assisted Radical Prostatectomy (RS-RARP) is a novel surgical approach to radical prostatectomy. Its pioneers have suggested an improved recovery of urinary continence, while maintaining adequate cancer control. Aim of this systematic review is to explore available data on RS-RALP and compare functional, oncologic and perioperative results of RS-RARP compared to anterior RARP.

EVIDENCE ACQUISITION

A search following PRISMA guidelines was performed including the combination of the following words: retzius AND sparing AND radical AND prostatectomy. 93 articles were identified and 13 were included in the systematic review, including 3 randomized controlled trials (RCT), 4 prospective studies and 6 retrospective studies.

EVIDENCE SYNTHESIS

All available randomized trials confirmed an improved immediate continence for RS-RARP, with rates ranging 51-71%, compared to 21-48% for anterior RARP. However, this advantage was progressively lost with no significant difference found after 6 months. Moreover, a prospective study found no discrepancy in terms of quality of life across the two techniques. Erectile function was difficult to compare, as patients had different baseline erectile function across studies and rate of neurovascular preservation was not comparable. Surgical approach remains controversial regarding positive margin rate, although related to the surgeon's experience and clinical stage. Biochemical recurrence-free survival appears similar between the two approaches.

CONCLUSIONS

RS-RARP improves early urinary continence recovery compared to anterior RARP, with this advantage being lost after 3 to 6 months. Erectile function and quality of life were however comparable between the two techniques. The results concerning the rate of positive margins remained controversial. Future studies with longer follow-up are needed to better assess oncologic outcomes.

Real-time, functional intra-operative localization of rat cavernous nerve network using near-infrared cyanine voltage-sensitive dye imaging

Despite current progress achieved in the surgical technique of radical prostatectomy, post-operative complications such as erectile dysfunction and urinary incontinence persist at high incidence rates. In this paper, we present a methodology for functional intra-operative localization of the cavernous nerve (CN) network for nerve-sparing radical prostatectomy using near-infrared cyanine voltage-sensitive dye (VSD) imaging, which visualizes membrane potential variations in the CN and its branches (CNB) in real time. As a proof-of-concept experiment, we demonstrate a functioning complex nerve network in response to electrical stimulation of the CN, which was clearly differentiated from surrounding tissues in an in vivo rat prostate model. Stimulation of an erection was confirmed by correlative intracavernosal pressure (ICP) monitoring. Within 10 minutes, we performed trans-fascial staining of the CN by direct VSD administration. Our findings suggest the applicability of VSD imaging for real-time, functional imaging guidance during nerve-sparing radical prostatectomy.

A prediction model relating the extent of intraoperative fascia preservation to erectile dysfunction after nerve-sparing robot-assisted radical prostatectomy

Robot-assisted radical prostatectomy (RARP) is performed in patients with prostate cancer. Unfortunately, 10-46% of patients may still suffer from limited erectile function (EF) after RARP. This study aimed to develop a prediction model based on the extent of fascia preservation (FP) and postoperative EF after RARP. A previously developed FP score quantizing the extent and regions of nerve-preservation was determined in a cohort of 1241 patients who underwent RARP. The predictive value of the FP score for post-prostatectomy EF (following the international index erectile function (IIEF) score, EF domain) was analyzed. To increase the predictive value of the scoring system, the FP regions were related to postoperative EF, nerve distribution and co-morbidity factors. Finally, a prediction model for EF was developed based on the studied cohort. When corrected for the preoperative IIEF-EF, the FP score was shown to be a significant denominator for IIEF (p = 2.5 × 10^- 15) with an R² of 35%. Variable selection performed using the Akaike information criterion led to a final prediction model for postoperative IIEF after nerve-preservation based on the FP score. Furthermore, patient's age, preoperative IIEF score, CCIS and use of clips for nerve sparing were significantly associated with postoperative IIEF-EF. More anterior fascia preservation was correlated with better EF outcome and age was a strong independent predictor of EF outcome. In older men, the relative benefit of more extensive fascia preservation was at least similar to younger men, despite a lower baseline IIEF-EF score. Quantitative nerve-sparing FP scoring could be related to the postoperative IIEF-EF and integrated into a multivariate prediction model, which includes with age, use of surgical clips, the Charlson Comorbidity Index Score (CCIS), and preoperative IIEF-EF. When further validated the prediction model could provide patients and care-givers a qualitative estimation of EF outcome after RARP.

Surgical Factors Associated With Male and Female Sexual Dysfunction After Radical Cystectomy: What Do We Know and How Can We Improve Outcomes?

BACKGROUND

Sexual dysfunction after radical cystectomy (RC) is a frequent, though commonly overlooked symptom for both men and women. Improved oncological outcomes and the rising number of bladder cancer survivors mandate physicians to closely address and evaluate post-surgical sexual dysfunction and offer goal-directed treatment. Improvements in RC surgical techniques that promote post-operative sexual function have been proposed, alongside new quality-of-life inventories and sexual function therapeutic options; however, rigorous studies in the field are lacking.

AIM

To provide a comprehensive overview of post-RC sexual dysfunction and discuss new surgical techniques, sexual dysfunction evaluation, and novel treatment strategies.

METHODS

A non-systematic narrative review of the literature was performed through PubMed about sexual dysfunction in men and women after RC.

OUTCOMES

We reported on the surgical anatomy of sexual function-sparing RC, the most common inventories used to investigate sexual function in post-RC patients, and current treatment options.

RESULTS

Extensive knowledge about pelvic anatomy and nerve-sparing surgical techniques in men is well understood from studies about prostate anatomy and nerve-sparing prostatectomy. However, anatomical and surgical details of sexual-sparing RC in women needs further characterization. Several questionnaires are used to investigate sexuality after RC, but a standardized approach is still missing. Therapeutic options are available to treat sexual dysfunction, but limited studies have been conducted to specifically address the post-RC population.

CONCLUSION

Further work is needed to understand the best strategies to prevent and treat sexual dysfunction in patients after RC. Pederzoli F, Campbell JD, Matsui H, et al. Surgical Factors Associated With Male and Female Sexual Dysfunction After Radical Cystectomy: What Do We Know and How Can We Improve Outcomes? Sex Med Rev 2018;6:469-481.

Visualization of prostatic nerves by polarization-sensitive optical coherence tomography

Preservation of prostatic nerves is critical to recovery of a man's sexual potency after radical prostatectomy. A real-time imaging method of prostatic nerves will be helpful for nerve-sparing radical prostatectomy (NSRP). Polarization-sensitive optical coherence tomography (PS-OCT), which provides both structural and birefringent information of tissue, was applied for detection of prostatic nerves in both rat and human prostate specimens, ex vivo. PS-OCT imaging of rat prostate specimens visualized highly scattering and birefringent fibrous structures superficially, and these birefringent structures were confirmed to be nerves by histology or multiphoton microscopy (MPM). PS-OCT could easily distinguish these birefringent structures from surrounding other tissue compartments such as prostatic glands and fats. PS-OCT imaging of human prostatectomy specimens visualized two different birefringent structures, appearing fibrous and sheet-like. The fibrous ones were confirmed to be nerves by histology, and the sheet-like ones were considered to be fascias surrounding the human prostate. PS-OCT imaging of human prostatectomy specimens along the perimeter showed spatial variation in the amount of birefringent fibrous structures which was consistent with anatomy. These results demonstrate the feasibility of PS-OCT for detection of prostatic nerves, and this study will provide a basis for intraoperative use of PS-OCT.

Novel anatomical identification of nerve-sparing radical prostatectomy: fascial-sparing radical prostatectomy

Radical prostatectomy (RP) became a first choice of treatment for prostate cancer after the advance in nerve-sparing techniques. However, the difficult technical details still involved in nerve-sparing RP (nsRP) can invite unwanted complications. Therefore, learning to recognize key anatomical features of the prostate and its surrounding structures is crucial to further improve RP efficacy. Although the anatomical relation between the pelvic nerves and pelvic fascias is still under investigation, this paper characterizes the periprostatic fascias in order to define a novel fascial-sparing approach to RP (fsRP), which will help spare neurovascular bundles. In uroanatomic perspective, it can be stated that nsRP is a functional identification of the surgical technique while fsRP is an anatomic identification as well. The functional and oncological outcomes related to this novel fsRP are also reviewed.