Topographical Anatomy of Periprostatic and Capsular Nerves: Quantification and Computerised Planimetry

Distribution of neurovascular structures within the prostate gland and their relationship to complications after radical prostatectomy

BACKGROUND

Radical prostatectomy remains the main choice of treatment for prostate cancer. However, despite improvements in surgical techniques and neurovascular sparing procedures, rates of erectile dysfunction, and urinary incontinence remain variable. This is due, at least in part, to an incomplete understanding of neurovascular structures associated with the prostate. The objective of this study was to provide a comprehensive, detailed histological overview of the distribution of nerves and blood vessels within the prostate, facilitating subsequent correlation of prostatic neurovascular structures with patients' clinical outcomes after radical prostatectomy.

METHODS

Neurovascular structures within the prostate were investigated in a total of 309 slides obtained from 15 patients who underwent non-nerve-sparing radical prostatectomy. Immunohistochemical staining was performed to identify and distinguish between parasympathetic and sympathetic nerves, whereas hematoxylin and eosin staining was used to identify blood vessels. The total number, density, and relative position of nerves and blood vessels were established using quantitative morphometry and illustrated using visualization approaches. Patient-specific outcome data were then used to establish whether the internal distribution of nerves and blood vessels within the prostate correlated with the nature and extent of complications after surgery. One-way analysis of variance tests and unpaired t tests were applied to establish statistically significant differences across the measured variables.

RESULTS

Nerves and blood vessels were present across all prostatic levels and regions. However, their number and density varied considerably between regions. Assessment of the precise positioning of neurovascular structures revealed that the majority of nerve fibers were located within the dorsal and peripheral aspects of the gland. In contrast, blood vessels were predominantly located within ventral and dorsal midline regions. The number of intraprostatic nerves was found to be significantly lower in patients who recovered their continence within 12 months of surgery, compared to those whose recovery took 12 months or longer.

CONCLUSION

We report an unexpected disconnect between the localization and positioning of nerve fibers and blood vessels within the prostate. Moreover, individual variability in the density of intraprostatic neurovascular structures appears to correlate with the successful recovery of urinary continence after radical prostatectomy, suggesting that differences in intrinsic neurovascular arrangements of the prostate influence postoperative outcomes.

[Urinary incontinence after radical prostatectomy: risk factors and utilisation of care]

Stress urinary incontinence is a relevant risk of radical prostatectomy (RP), which significantly affects patients' quality of life. The risk of developing stress urinary incontinence depends on pre-, intra- and postoperative factors. In particular, intraoperative factors regarding different surgical techniques are often focused on in order to improve continence rates. If stress urinary incontinence develops after RPE, patients affected should be treated adequately. In this respect, there are indications of healthcare insufficiencies in Germany. On the one hand, these include deficits in the use of incontinence materials. On the other hand, surgical treatment of stress urinary incontinence after RPE is insufficient.

Impact of Early Dorsal Venous Complex Ligation on Urinary Continence Recovery after Robot-assisted Radical Prostatectomy: Results from a Phase 3 Randomized Controlled Trial

BACKGROUND

Whether early ligation of the dorsal venous complex (DVC) might improve recovery of urinary continence (UC) after robot-assisted radical prostatectomy (RARP) has never been investigated in a prospective randomized study.

OBJECTIVE

To assess whether early DVC ligation might affect UC recovery after RARP.

INTERVENTION

DVC ligation (early vs standard).

DESIGN, SETTING, AND PARTICIPANTS

A total of 312 patients with prostate cancer underwent primary RARP at a tertiary care institution.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was UC recovery at 1 and 4 mo after RARP. UC was defined as 0 pads/1 safety pad per day. All patients completed the International Prostate Symptom Score (IPSS) and International Consultation of Incontinence Questionnaire (ICIQ)-Short Form questionnaires. Secondary outcomes were early (≤4 mo) erectile function recovery, the positive surgical margin (PSM) rate, 30-d Clavien-Dindo complications, and biochemical recurrence rates. Quality of life was assessed using the EQ-5D-5L questionnaire. The association between treatment arm and UC recovery was also tested using multivariable regression models.

RESULTS AND LIMITATIONS

After surgery, 23 patients withdrew their consent and 29 were lost to follow-up, leaving 261 patients available for per-protocol analyses. Of these, 32 patients (24%) in the experimental group and 37 (29%) in the control group used no pad/one safety pad at 1 mo after RARP, whereas 96 (72%) in the control group versus 83 (65%) in the control group were continent at 4-mo follow-up (both p = 0.3). Median ICIQ and IPSS scores did not differ between the groups at both time points. The results were confirmed on multivariable regression analyses. PSMs were observed for 32 patients (25%) in the experimental group versus 30 (22%) in the control group (p = 0.6). The incidence of postoperative complications (17% experimental vs 13% control) and the 1-yr biochemical recurrence-free survival did not differ between the groups.

CONCLUSIONS

In this randomized clinical trial, we did not find evidence that early ligation of the DVC during RARP was associated with better UC recovery after surgery in comparison to the standard technique. Given its safety in terms of surgical margins and complications, this technique may be considered as an option for surgical dissection according to the physician's preference.

PATIENT SUMMARY

Our trial showed that for patients undergoing robot-assisted surgical removal of the prostate, the timing of a specific step to control bleeding from a network of veins draining the prostate did not affect recovery of urinary continence after surgery. The results indicate that earlier control of these veins may be considered as an option according to the surgeon's preference.

Objective quantification of nerves in immunohistochemistry specimens of thyroid cancer utilising deep learning

Accurate quantification of nerves in cancer specimens is important to understand cancer behaviour. Typically, nerves are manually detected and counted in digitised images of thin tissue sections from excised tumours using immunohistochemistry. However the images are of a large size with nerves having substantial variation in morphology that renders accurate and objective quantification difficult using existing manual and automated counting techniques. Manual counting is precise, but time-consuming, susceptible to inconsistency and has a high rate of false negatives. Existing automated techniques using digitised tissue sections and colour filters are sensitive, however, have a high rate of false positives. In this paper we develop a new automated nerve detection approach, based on a deep learning model with an augmented classification structure. This approach involves pre-processing to extract the image patches for the deep learning model, followed by pixel-level nerve detection utilising the proposed deep learning model. Outcomes assessed were a) sensitivity of the model in detecting manually identified nerves (expert annotations), and b) the precision of additional model-detected nerves. The proposed deep learning model based approach results in a sensitivity of 89% and a precision of 75%. The code and pre-trained model are publicly available at https://github.com/IA92/Automated_Nerves_Quantification.

The study of nerves as a prognostic marker for cancer is becoming increasingly important. However, accurate quantification of nerves in cancer specimens is difficult to achieve due to limitations in the existing manual and automated quantification methods. Manual quantification is time-consuming and subject to bias, whilst automated quantification, in general, has a high rate of false detections that makes it somewhat unreliable. In this paper, we propose an automated nerve quantification approach based on a novel deep learning model structure for objective nerve quantification in immunohistochemistry specimens of thyroid cancer. We evaluate the performance of the proposed approach by comparing it with existing manual and automated quantification methods. We show that our proposed approach is superior to the existing manual and automated quantification methods. The proposed approach is shown to have a high precision as well as being able to detect a significant number of nerves not detected by the experts in manual counting.

Anatomical Fundamentals and Current Surgical Knowledge of Prostate Anatomy Related to Functional and Oncological Outcomes for Robotic-Assisted Radical Prostatectomy

Context

Meticulous knowledge about the anatomy of the prostate and surrounding tissue represents a crucial and mandatory requirement during radical prostatectomy for reliable oncological and excellent replicable, functional outcomes. Since its introduction two decades ago, robotic-assisted laparoscopic radical prostatectomy (RALP) has evolved to become the predominant surgical approach in many industrialized countries.

Objective

To provide and highlight currently available literature regarding prostate anatomy and to help in improving oncological and functional outcomes in RALP.

Methods/Evidence Acquiring

PubMed database was searched using the following keywords: “robotic-assisted radical prostatectomy,” “anatomy,” “neurovascular bundle,” “nerve,” “periprostatic fascia,” “pelvis,” “sphincter,” “urethra,” “urinary incontinence,” and “erectile dysfunction.” Relevant articles and book chapters were critically reviewed and if eligible, they were included in this review.

Results

New evidence in regards to prostatic anatomy and surgical approaches in RALP has been reported in recent years. Besides detailed anatomical studies investigating the meticulous structure of the fascial structures surrounding the prostate and neurovascular bundle preservation, debate about the optimal RALP approach is still ongoing, inspired by recent publications presenting promising functional outcomes following modifications in surgical approaches.

Conclusions

This review provides a detailed overview of the current knowledge of prostate anatomy, its surrounding tissue, and its influence on key surgical step development for RALP.

Improvement in early continence after introduction of periurethral suspension stitch in robotic prostatectomy

Early urinary incontinence remains a major source of morbidity for patients undergoing robotic prostatectomy. The purpose of the study was to determine whether the introduction of a suspension stitch would improve early urinary continence rates in patients undergoing robotic prostatectomy for localized prostate cancer at our department. We retrospectively reviewed patients undergoing robotic prostatectomy with either suspension (n = 119) or figure-of-eight (n = 48) stitching of the dorsal venous complex. The patients submitted EPIC-26 questionnaires before surgery and after 3 and 18 months, respectively. Logistic regression analysis was run to determine the effect of the suspension stitch, nerve-sparing, posterior reconstruction, prostate volume, age and body mass index on early continence rate. The odds ratio of experiencing urinary leaks was 2.1 times higher (95% CI 1.0–4.3) in the figure-of-eight stitch group compared to the suspension stitch group 3 months after surgery (p < 0.05). The early urinary continence rate was 61.3% in the suspension stitch group compared to 35.4% in the figure-of-eight stitch group (p < 0.005). There were no differences between the groups 18 months post-prostatectomy (90.7% in the suspension stitch group versus 81.4% in the non-suspension stitch group, p = 0.1). Ordinal regression analysis identified the suspension stitch, bilateral nerve-sparing and body mass index as independent predictors of urinary continence at 3 months. The association between urinary continence and either unilateral nerve-sparing, posterior reconstruction, prostate volume or age did not reach statistical significance. Our results suggest that the suspension stitch improved early urinary continence following robotic prostatectomy.

A new method in robotic-assisted laparoscopic radical prostatectomy: personalised neuroprotective surgery with neuromonitoring system-randomised controlled study

PURPOSE

Erectile dysfunction is one of the important morbidities following the radical prostatectomy (RP) surgeries. The goal of this research is to investigate the contribution of intraoperative neuromonitorisation method (IONM) on postoperative erectile function in patients who underwent robotic-assisted laparoscopic radical prostatectomy (RALP) with the localise prostate cancer (LPCa).

MATERIALS AND METHODS

In this randomised controlled study contains 88 patients with LPCa were classified based on D'Amico Risk Classification. 61 patients who met the necessary criteria were divided into two groups as neuromonitorisation group (n = 30) and control group (n = 31). All patients were operated under general anaesthesia. All patients included in the study underwent RALP by robotic-assisted system. For the neuromonitorisation, IONM electromyography electrodes were placed to the right and left cavernous bodies in neuromonitorisation group. Impulses in the corpora cavernosa were considered significant. Postoperative erectile functions were determined according to the 3th and 6th month IIEF-5 scores. Demographic data, operative procedures, Gleason scores, final pathology, surgery border, PSA, and IIEF-5 score of patients were recorded.

RESULTS

No statistically difference was found between the groups in terms of demographic data, operative procedures, Gleason scores, final pathology, surgery border, and third-month PSA levels (p > 0.05). There was statistically difference between the postoperative third and 6-month IIEF-5 score in neuromonitorisation group (p < 0.05).

CONCLUSION

In the IONM technique, high rate of improvement in erectile function was observed in the early period thanks to personalised neuroprotective surgery applied to patients.

Neuro-anatomic basis of potency recovery after radical prostatectomy: an expert's point of view

INTRODUCTION

From 25% to 95% of those who have undergone radical prostatectomy (RP) report erectile dysfunction 12 months after surgery. We attempt a review of the available evidence regarding the anatomy of the cavernous nerves and the surgical refinements to enhance sexual function recovery after surgery.

EVIDENCE ACQUISITION

The PubMed/Medline database was searched. Duplicates were removed. Studies were selected by the authors according to the aim of the present review.

EVIDENCE SYNTHESIS

The cavernous nerves are deemed responsible for erections, but their exact function is still a matter of debate. They do not necessarily have the same distribution in all individuals: in most the cases, these nerves are located posterolaterally, however, it is not uncommon to find some fibers on the anterolateral aspects of the prostate, especially towards the apex. Several technical strategies were proposed in order to intraoperatively identify and spare the neurovascular bundles: despite all efforts, clinical results are still only partially satisfying.

CONCLUSIONS

The recovery of potency is one of the most unpredictable outcomes after RP. The advent of the robotic surgical system seems to have brought a trend towards a faster recovery of erectile function.

Intrafascial nerve-sparing radical prostatectomy improves patients' postoperative continence recovery and erectile function: A pooled analysis based on available literatures

BACKGROUND

Intrafascial nerve-sparing prostatectomy has been currently applied based on the updated anatomic understanding of periprostatic cavernous nerves, in order to provide patients better postoperative recovery of continence and potency. The aim of our study is to perform a pooled analysis of available literatures regarding the functional outcomes following intrafascial nerve-sparing technique.

METHODS

The authors performed database searches of articles published till October 2017 on PubMed using following keywords across the "title" and "abstract" field of the records: intrafascial, veil, curtain dissection, high anterior release, incremental nerve sparing, and radical prostatectomy. Fulfilled papers were screened and data were extracted independently by 3 reviewers. Main outcome was the postoperative continence and potency rate stratified by follow-up durations. Both 1-arm and comparative meta-analyses were performed and meta-regression models were conducted to evaluate the confounding factors.

RESULTS

Using the electronic search strategy, a total of 71 records were retrieved and 20 studies were finally included, of which 6 were surgical series and 14 were controlled studies. Our 1-arm meta-analysis summarized the pooled continence rates after intrafascial prostatectomy were 59.4%, 76.2%, 89.9%, and 92.2% at postoperative follow-up of 1, 3, 6, and 12 months, respectively. Regardless of the variance in potency definition, the pooled potency rates after intrafascial prostatectomy were 42.2%, 54.2%, and 72.2% at 3, 6, and 12 months, respectively. Comparative analysis showed that the intrafascial group offered better continence rates at 1, 3, and 6 months with an odds ratio (OR) of 2.38 (95% confidence interval [CI]: 1.73-3.26), 1.82 (95% CI: 1.18-2.82), and 2.19 (95% CI: 1.43-3.34) as compared with the interfascial group. Moreover, potency rate in the intrafascial group was higher at 12 months than in the interfascial group, with an OR of 2.44 (95% CI: 1.35-4.42).

CONCLUSION

Based on the limited evidence, our study demonstrated that intrafascial nerve-sparing prostatectomy could provide patients with earlier recovery of continence and better erectile function compared with conventional interfascial approach, but physiological mechanisms about this technique still need further study.

Reappraisal of the lateral rectal ligament: an anatomical study of total mesorectal excision with autonomic nerve preservation

PURPOSE

The term "lateral rectal ligament" in surgery for rectal cancer has caused confusion regarding its true existence and contents. In previous studies, investigators claimed the existence of the ligament and described its topographical features as neurovascular structures and their surrounding connective tissues located at the anterolateral aspect of the distal rectum or the posterolateral aspect of the middle rectum. The purpose of this study is to evaluate the structure of the so-called "lateral rectal ligament" in cadaver dissections.

METHODS

Dissection was performed in nine cadavers (eight males and one female, aged 73 to 94 years) in accordance with typical total mesorectal excision techniques. During dissection, structures related to "the ligament" were examined and images recorded.

RESULTS

At the anterolateral aspect of the distal rectum, the middle rectal artery was noted to be crossing the fusion of Denonvilliers' fascia and the proper rectal fascia. At the posterolateral aspect of the middle rectum, there was a structure which consisted of the rectal nerves running through the fusion of the pelvic fasciae. Although called "ligaments," neither structure contained discrete strong connective tissue fixing the rectum to the pelvic wall.

CONCLUSIONS

The proper rectal fascia and surrounding pelvic fasciae fuse firmly anterolaterally and posterolaterally where neurovascular structures course toward the rectum. During a total mesorectal excision, the surgical dissection plane coincides with the fused part of the fasciae, which had long been considered the "lateral rectal ligament."

Comparison of intrafascial and non-intrafascial radical prostatectomy for low risk localized prostate cancer

In this meta-analysis study, we compared the oncological and functional outcomes of intrafascial radical prostatectomy (IFRP) with non-intrafascial radical prostatectomy (NIFRP) in the treatment of patients with low risk localized prostate cancer (PCa). Relevant articles were identified by searching PubMed, EMBASE, Cochrane Library, Ovid, and the ISI Web of Knowledge databases. A total of 2096 patients were included from 7 eligible studies. Results of the pooled data showed that the oncological outcomes including gleason score, positive surgical margin and biochemical free survival rates were similar between the two groups. IFRP was superior to NIFRP with lower postoperative complication rates (RR 0.57, 95% CI 0.38, 0.85, p = 0.006), higher continence rates at 3 months post-operation (RR: 1.14; 95% CI, 1.04, 1.26; p = 0.006), and higher potency rates at 6 months (RR: 1.53; 95% CI, 1.07, 2.18; p = 0.02) and 12 months post-operation (RR: 1.38; 95% CI, 1.11, 1.73; p = 0.005). Additionally, there was a tendency towards higher potency rate in patients ≤65 years old compared with patients >65 years old after IFRP. Overall, these findings suggest that IFRP in young patients with low risk localized PCa had less postoperative complications, shortened time to return to continence and improved potency rate without compromising complete tumor control.

Influence of fractional anisotropy thresholds on diffusion tensor imaging tractography of the periprostatic neurovascular bundle and selected pelvic tissues: do visualized tracts really represent nerves?

Background Diffusion tensor imaging (DTI) tractography has recently been shown to successfully visualize periprostatic tracts allegedly representing the neurovascular bundle. Purpose To examine the impact of different fractional anisotropy (FA) thresholds on the results of DTI tractography in the male pelvis as well as to evaluate the resulting specificity for nerve tracts. Material and Methods Ten healthy male volunteers were examined at 3 Tesla. DTI tractography was performed based on seed points placed circularly around the prostate, in the rectoprostatic angle, the peripheral zone of the prostate, the sciatic nerve, and in addition the urinary bladder using FA thresholds of 0.20, 0.05, and 0.01. DTI tract number and DTI tract length measured with different FA thresholds were compared. ANOVA with repeated measures was used for statistics. Results DTI tract number and tract length were significantly dependent on FA thresholds. While a FA threshold of 0.20 visualized the typical distribution of DTI tracts in the sciatic nerve, a FA threshold of ≤0.05 was necessary to yield results visually mimicking the distribution of nerve tracts in the NVB. However, with such low FA thresholds even in the filled urinary bladder DTI tracts could be visualized. With FA thresholds of 0.20, the number and length of periprostatic DTI tracts did not differ from those measured within the prostate. Conclusion DTI tractography can be used to visualize DTI tracts periprostatically. However, one may doubt that these DTI tracts represent nerve tracts and that the periprostatic neurovascular bundle can be evaluated in a meaningful way with the current methods available.

Nerve-sparing techniques and results in robot-assisted radical prostatectomy

Nerve-sparing techniques in robot-assisted radical prostatectomy (RARP) have advanced with the developments defining the prostate anatomy and robotic surgery in recent years. In this review we discussed the surgical anatomy, current nerve-sparing techniques and results of these operations. It is important to define the right and key anatomic landmarks for nerve-sparing in RARP which can demonstrate individual variations. The patients' risk assessment before the operation and intraoperative anatomic variations may affect the nerve-sparing technique, nerve-sparing degree and the approach. There is lack of randomized control trials for different nerve-sparing techniques and approaches in RARP, therefore accurate preoperative and intraoperative assessment of the patient is crucial. Current data shows that, performing the maximum possible nerve-sparing using athermal techniques have better functional outcomes.

Full Neurovascular Sparing Extraperitoneal Robotic Radical Prostatectomy: Our Experience with PERUSIA Technique

INTRODUCTION

Primary aim of this study was to investigate the feasibility and the safety of PERUSIA (posterior, extraperitoneal, robotic, under santorini, intrafascial, anterograde) radical prostatectomy (RP). Secondary aim was to evaluate oncologic and functional results. The main intent of PERUSIA is to reduce injury of the Neuro-Vascular Bundles (NVB) and to preserve periurethral anterior structures. This is the first reported prospective cohort study about our technique.

MATERIALS AND METHODS

We collected prospective data of a cohort of 210 patients who had undergone PERUSIA RP between January 2013 and May 2015. Key points of this technique included the following: posterior approach to intrafascial plane, which was developed from the median to lateral side, anterograde preservation of the Veil of Aphrodite, and development of an anterior avascular plane to preserve the santorini plexus. We included only sexually potent patients with low-risk disease. Perioperative, oncologic, and functional outcomes were collected. Postoperative full continence was defined as no pad use. Patients were defined potent when International Index of Erectile Function (IIEF-5) score was >17. Median follow-up was 22 months.

RESULTS

Median operative time and median estimated blood loss were 120 minutes and 150 mL, respectively. 25 patients (11.9%) experienced a total of 36 complications overall with an overall complication rate of 17.1%. We reported 3 (8.3%) grade IIIb complications and no major ones. Overall positive surgical margin rate was 20% with biochemical recurrence occurring in 3.8% of patients at a median follow-up of 22 months. Immediate urinary continence rate (1 day after catheter removal) was 66.6%. At 3 and 12 months, the continence rate was 90.4% and 96.1%, respectively, while sexual potency rate was 70.4% and 80.9%.

CONCLUSION

PERUSIA RP has proved to be safe and effective for low-risk prostate cancer with exciting functional outcomes in terms of early recovery of urinary continence and sexual potency.

A Critical Analysis of the Current Knowledge of Surgical Anatomy of the Prostate Related to Optimisation of Cancer Control and Preservation of Continence and Erection in Candidates for Radical Prostatectomy: An Update

CONTEXT

In 2010, we published a review summarising the available literature on surgical anatomy of the prostate and adjacent structures involved in cancer control and the functional outcome of prostatectomy.

OBJECTIVE

To provide an update based on new literature to help the surgeon improve oncologic and surgical outcomes of radical prostatectomy (RP).

EVIDENCE ACQUISITION

We searched the PubMed database using the keywords radical prostatectomy, anatomy, neurovascular bundle, nerve, fascia, pelvis, sphincter, urethra, urinary continence, and erectile function. Relevant articles and textbook chapters published since the last review were critically reviewed, analysed, and summarised. Moreover, we integrated aspects that were not addressed in the last review into this update.

EVIDENCE SYNTHESIS

We found new evidence for several topics. Up to 40% of the cross-sectional surface area of the urethral sphincter tissue is laterally overlapped by the dorsal vascular complex and might be injured during en bloc ligation. Denonvilliers fascia is fused with the base of the prostate in a horizontal fashion dorsally/caudally of the seminal vesicles, requiring sharp detachment when preserved. During extended pelvic lymph node dissection, the erectile nerves are at risk in the presacral and internal iliac area. Dissection planes for nerve sparing can be graded according to the amount of tissue left on the prostate as a safety margin against positive surgical margins. Vascular structures can serve as landmarks. The urethral sphincter and its length after RP are influenced by the shape of the apex. Taking this shape into account allows preservation of additional sphincter length with improved postoperative continence.

CONCLUSIONS

This update provides additional, detailed information about the surgical anatomy of the prostate and adjacent tissues involved in RP. This anatomy remains complex and widely variable. These details facilitate surgical orientation and dissection during RP and ideally should translate into improved outcomes.

PATIENT SUMMARY

Based on recent anatomic findings regarding the prostate and its surrounding tissue, the urologist can individualise the dissection during RP according to cancer and patient characteristics to improve oncologic and functional results at the same time.

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.

Visualization of periprostatic nerve fibers before and after radical prostatectomy using diffusion tensor magnetic resonance imaging with tractography

PURPOSE

The purpose was to evaluate whether the diffusion tensor imaging (DTI) technique can visualize changes in the numbers of periprostatic nerve fibers before and after nerve-sparing and non-nerve-sparing prostatectomy.

METHOD

Fifty-two prostate cancer patients underwent 3-T magnetic resonance imaging including DTI before and after prostatectomy.

RESULTS

After non-nerve-sparing prostatectomy, the numbers of tracts were significantly decreased at base (218.8±198.8 vs. 60.5±88.7), midgland (124.1±134.5 vs. 32.5±45.7), and apex (103.1±127.4 vs. 29.1±57.1). However, after nerve-sparing prostatectomy, the numbers of tracts were not changed significantly at base (170.5±139.7 vs. 127.7±146.0), midgland (134.3±140.8 vs. 83.7±58.3), and apex (64.1±68.4 vs. 62.3±61.9).

CONCLUSION

DTI technique may be feasible for visualization of periprostatic nerve fibers.

A comprehensive review of neuroanatomy of the prostate

Although oncologic efficacy is the primary goal of radical prostatectomy, preserving potency and continence is also important, given the indolent clinical course of most prostate cancers. In order to preserve and recover postoperative potency and continence after radical prostatectomy, a detailed understanding of the pelvic anatomy is necessary to recognize the optimal nerve-sparing plane and to minimize injury to the neurovascular bundles. Therefore, we reviewed the most recent findings from neuroanatomic studies of the prostate and adjacent tissues, some of which are contrary to the established consensus on pelvic anatomy. We also described the functional outcomes of radical prostatectomies following improved anatomical understanding and development of surgical techniques for preserving the neurovascular bundles.

Single-port transvesical laparoscopic radical prostatectomy for organ-confined prostate cancer: technique and outcomes

OBJECTIVE

To report a novel technique for performing single-port transvesical laparoscopic radical prostatectomy (STLRP) and to evaluate the oncological and functional outcomes in 16 patients with organ-confined prostate cancer.

PATIENTS AND METHODS

In total, 16 consecutive patients with clinical stage T1-2aN0M0 were scheduled for STLRP, and their continence and erectile status were investigated preoperatively. The patients' mean age was 62 years, mean prostate volume 42 mL and mean prostate-specific antigen (PSA) 7.5 ng/mL. The STLRP procedures were performed by a single surgeon, and all the operating procedures were conducted transvesically and laparoscopically. Intra-operative and postoperative complications, assessed according to the modified Clavien system, were recorded and peri-operative and functional outcome data were analysed. All patients were followed up for a minimum of 12 months postoperatively through PSA detection, daily pads, the International Index of Erectile Function (IIEF)-6 score and urography.

RESULTS

All of the 16 STLRP procedures were successfully completed. The mean (range) operation duration was 105 (75-180) min, and the mean (range) estimated blood loss was 130 (75-500) mL. No patients had positive surgical margins. Postoperative complications occurred in five patients, including three cases of urinary infection and two cases of haematuria (grade II). Catheters were removed after a mean (range) time of 11.2 (9-14) days with cystography. The mean (range) hospital stay was 12.7 (10-15) days. Of the 16 patients, 13 were immediately continent (0 pads/day), and three had mild incontinence (2-3 pads/day) after catheter removal. All patients were observed as continent 3 months postoperatively. In total, 10/16 and 12/16 patients achieved a satisfactory erection at 6 and 12 months follow-up postoperatively, respectively, with an IIEF-6 score ≥ 18. The mean postoperative PSA levels at 3, 6 and 12 months were 0.015 ng/mL, 0.017 ng/mL and 0.016 ng/mL, respectively. No patients were identified with biochemical recurrence in this series. No patients demonstrated vesico-urethral stricture during follow-up for 12-24 months.

CONCLUSIONS

We conclude that STLRP is technically feasible for patients with low-risk organ-confined prostate cancer and demonstrates promising functional outcomes regarding continence and potency.

Computerized quantification and planimetry of prostatic capsular nerves in relation to adjacent prostate cancer foci

BACKGROUND

Perineural invasion is discussed as a significant route of extraprostatic extension in prostate cancer (PCa). Recent in vitro studies suggested a complex mechanism of neuroepithelial interaction.

OBJECTIVE

The present study was intended to investigate whether the concept of neuroepithelial interaction can be supported by a quantitative analysis and planimetry of capsular nerves in relation to adjacent PCa foci.

DESIGN, SETTING, AND PARTICIPANTS

Whole-mount sections of the prostate were created from patients undergoing non-nerve-sparing laparoscopic radical prostatectomy. For each prostate, adjacent sections were created and stained both to identify capsular nerves (S100) and to localize cancer foci (hematoxylin and eosin).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Computerized quantification and planimetry of capsular nerves (ImageJ software) were performed after applying a digital grid to define 12 capsular sectors. For statistical analyses, mixed linear models were calculated using the SAS 9.3 software package.

RESULTS AND LIMITATIONS

Specimens of 33 prostates were investigated. A total of 1957 capsular nerves and a total capsular nerve surface area of 26.44 mm(2) were measured. The major proportion was found in the dorsolateral (DL) region (p<0.001). Adjacent tumor was associated with a statistically significant higher capsular nerve count compared with the capsules of tumor-free sectors (p<0.005). Similar results were shown for capsular nerve surface area (p<0.006). Subsequent post hoc analyses at the sector level revealed that the effect of tumor on capsular nerve count or nerve surface area is most pronounced in the DL region.

CONCLUSIONS

The presence of PCa foci resulted in a significantly increased capsular nerve count and capsular nerve surface area compared with tumor-free sectors. The present study supports former in vitro findings suggesting that the presence of PCa lesions may lead to complex neuroepithelial interactions resulting in PCa-induced nerve growth.

Generating prostate models by means of geometric deformation with application to computerized training of cryosurgery

PURPOSE

As a part of an ongoing project to develop computerized training tools for cryosurgery, the objective of the current study is twofold: to compile literature data on the likelihood of cancer tumor growth and its effect on the prostate shape and to present a deformation scheme for a 3D organ template in order to generate clinically relevant prostate models. The long-term objective of this study is to develop a database of prostate models for computerized training.

METHODS

Cryosurgery is typically performed on patients with localized prostate cancer found in stage T3 or earlier. The distribution of key geometric features likely to be found in the prostate at stage T3 is integrated into a 3D prostate template by employing the extended free-form deformation (EFFD) method. The applied scheme combines two steps: pre-selecting a set of geometric parameter values and manipulating the lattice control points until the prostate model meets the desired criteria.

RESULTS

Examples for model generation are displayed, based on two 3D prostate templates previously obtained from ultrasound imaging. These examples include selected cases with unilateral and bilateral stage T3 tumor growth, suitable for incorporation into a training database.

CONCLUSIONS

EFFD is an efficient method for rapid generation of prostate models. The compiled criteria for model generation do not lead to a unique shape since the contours for template deformation are randomly selected. Nevertheless, these criteria do lead to shapes resembling cancer growth, as various growth histories can lead to a tumor characterized by the same key parameter values.

Preliminary results for continence recovery after intrafascial extraperitoneal laparoscopic radical prostatectomy

Purpose

We present our initial experience and surgical outcomes for the most recent refinement of bilateral intrafascial nerve-sparing extraperitoneal laparoscopic radical prostatectomy (nsELRP).

Materials and Methods

Among 62 patients who underwent laparoscopic radical prostatectomy, 50 patients underwent intrafascial nsELRP by a single surgeon at Pusan National University Hospital from November 2011 to April 2012. As part of the intrafascial technique, the dissection plane is directly on the prostatic capsule to preserve most of the periprostatic fascia containing small vessels and nerves, endopelvic fascia, neurovascular bundle, and puboprostatic ligament. Postoperative continence recovery was established by daily consumption of pads. Follow-up was done at 2 weeks, 6 weeks, and 3 months after surgery.

Results

The patients' mean age was 66.5±6.2 years. The mean operation time and mean blood loss were 149.3±28.1 minutes and 155.4±168.1 ml, respectively. The mean hospitalization time and mean catheterization time were 6.3±5.1 days and 5.5±4.7 days, respectively. Two weeks after the operation, a total of 14 patients (28.0%) were pad-free but the other incontinent patient group used on average 2.3 pads per day. After 6 weeks, 35 patients (70.0%) achieved pad-free status and 7 patients (14.0%) required more than 2 pads per day. At 3 months after surgery, a total of 31 patients were available for follow-up, and 26 patients (83.9%) were pad-free.

Conclusions

Compared with conventional laparoscopic prostatectomy, the intrafascial nsELRP procedure enables the preservation of periprostatic structures that are essential to the recovery of surgical structures related to continence. As a result, early postoperative continence can be achieved.

Perioperative betamethasone treatment reduces signs of bladder dysfunction in a rat model for neurapraxia in female urogenital surgery

BACKGROUND

Information on autonomic neurapraxia in female urogenital surgery is scarce, and a model to study it is not available.

OBJECTIVE

To develop a model to study the impact of autonomic neurapraxia on bladder function in female rats, as well as to assess the effects of corticosteroid therapy on the recovery of bladder function in this model.

DESIGN, SETTING, AND PARTICIPANTS

Female Sprague-Dawley rats were subjected to bilateral pelvic nerve crush (PNC) and perioperatively treated with betamethasone or vehicle. Bladder function and morphology of bladder tissue were evaluated and compared with sham-operated rats.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Western blot, immunohistochemistry, organ bath experiments, and cystometry.

RESULTS AND LIMITATIONS

Sham-operated rats exhibited regular micturitions without nonvoiding contractions (NVCs). Crush of all nerve branches of the pelvic plexus or PNC resulted in overflow incontinence and/or NVCs. Betamethasone treatment improved recovery of regular micturitions (87.5% compared with 27% for vehicle; p<0.05), reduced lowest bladder pressure (8 ± 2 cm H(2)O compared with 21 ± 5 cm H(2)O for vehicle; p<0.05), and reduced the amplitude of NVCs but had no effect on NVC frequency in PNC rats. Compared with vehicle, betamethasone-treated PNC rats had less CD68 (a macrophage marker) in the pelvic plexus and bladder tissue. Isolated bladder from betamethasone-treated PNC rats exhibited better nerve-induced contractions, contained more cholinergic and sensory nerves, and expressed lower amounts of collagen III than bladder tissue from vehicle-treated rats.

CONCLUSIONS

PNC causes autonomic neurapraxia and functional and morphologic changes of isolated bladder tissue that can be recorded as bladder dysfunction during awake cystometry in female rats. Perioperative systemic betamethasone treatment reduced macrophage contents of the pelvic plexus and bladder, partially counteracted changes in the bladder tissue, and had protective effects on micturition function.

Distribution of the lymphatic vessels in the prostatic fascia

BACKGROUND

The prostatic fascia-preserving procedure is effective for the early recovery of erectile function after radical prostatectomy; however, the long-term influence of on cancer control was unknown. This study clarified the distribution of lymphatic vessels in the prostatic fascia.

MATERIAL AND METHODS

The lymphatic vessels were analyzed in 10 prostates obtained from fixed Japanese cadavers (aged, 71-90 years old). Specimens were taken from the apex, the middle part, and the base of the right-hand side of the prostate. Lymphatic vessels were detected by immunohistochemical stain using an antibody specific for the lymphatic endothelial cells (clone D2-40). The lymphatic vessels were counted in the prostate capsule and the prostatic fascia of each section by light microscopy at low power (100×).

RESULTS

The median number of lymphatic vessels in the prostatic capsule per prostatic half was 21.0, 14.0, and 21.0 in the apex, middle, and base part of the prostate, respectively. In the prostatic facia the median number of lymphatic vessels per prostatic half was 8.0, 3.0, and 13.0 in the apex, middle, and the base part of the prostate, respectively. In the apex and the middle part the lymphatic vessels in the prostatic fascia were fewer than those in the prostatic capsule. However, in the base part the number of lymphatic vessels in the prostatic fascia was similar to that in the prostatic capsule.

CONCLUSIONS

The present study suggested the surgeon to pay more attention for the dissection of the fascia at the base of the prostate.

[Comparative study of periprostatic tissues thickness after retropubic or laparoscopic radical prostatectomy]

OBJECTIVE

Analysing periprostatic tissue (PPT) thickness after retropubic (RP) or laparoscopic (LP) prostatectomy.

MATERIAL

From January to December 2007, 114 consecutives prostatectomies were performed in our institution (38 RP, 76 LP). Clinical data were prospectively collected in a database. Gardner et al.'s (1988) procedure was used for pathological analysis. PPT thickness was measured on pathological specimens by a single observer on a single microscope. The observer had no knowledge of either clinical data or surgical approach. Four levels were chosen (at the base, the proximal part, the distal part, the apex) and 12 standardized measures were performed on each level, 48 measures: a prostate. We compared PPT thickness and surgical margins according to surgical approach and clinical data.

RESULTS

Comparative analysis confirmed that LP and RP groups were similar as far as it concerns preoperative and pathological findings. Positive margin rate was also similar in LP and RP groups (4% versus 5.3%; P=0,37). Overall PPT thickness was thinner after LP than after RP except at the apex and the anterior face. Nevertheless, in the "complete preservation" group, PPT thickness was thinner at the apex in the RP group, thinner at the base in the LP group.

CONCLUSION

Measuring PPT thickness was an original objective and reproducible way to compare different techniques and new technologies for radical prostatectomy. PPT sparing was different but not better with the laparoscopic approach.

Surgical anatomy of the prostate in the era of radical robotic prostatectomy

PURPOSE OF REVIEW

New insights in the anatomy of the prostate and the surrounding tissue evolve the technique of radical prostatectomy for the treatment of prostate cancer.

RECENT FINDINGS

Regarding the course of the erectile nerves along the prostate, recent studies confirmed the presence of parasympathetic pro-erectile nerve fibers at the anterolateral aspect of the prostate. Another study of intraoperative electrostimulation of those nerves confirmed an increase in intracavernosal pressure by stimulations between the 1 and 3 o'clock position. Therefore, it is very likely that these anterior nerve fibers have an effect on erectile function. Regarding the urethral sphincter in the male, a study showed no attachment of the external sphincter to the levator ani muscle, probably resulting in an absence of a levator ani support to the continence mechanism. The male urinary sphincter seems to be in isolation responsible for urinary continence.

SUMMARY

The nerve fibers at the anterolateral aspect of the prostate seem to participate in erectile function, which renders the concept of a high anterior release during nerve sparing beneficial. The isolated urinary sphincter mechanism results in the need to conserve as much urethral length as possible during radical prostatectomy to avoid urinary incontinence.

Natural orifice (NOTES) transurethral sutureless radical prostatectomy with thulium laser support: first patient report

INTRODUCTION

The aim of this descriptive study was to demonstrate the feasibility and safety of the first true transurethral sutureless radical prostatectomy for prostate cancer in humans using the NOTES technique.

MATERIALS AND METHODS

A 77-year-old man with clinically localized bilateral prostate cancer (Gleason 3 + 4 = 7 in 80% of 12 biopsy cores) and a serum PSA level of 2.1 ng/ml underwent our first natural orifice transurethral radical thulium laser prostatectomy within toto organ retrieval via sectio alta. The surgical procedure is described.

RESULTS

The procedure was completed successfully. Overall operation time was 312 min; laser time was 46 min with 151 KJ. Postoperative hemoglobin was 9.4 g/dl, and the hematocrit was 28%. A cystogram on the 7th postoperative day showed no signs of extravasation and the transurethral catheter was removed, and a flexible cystoscopy on the 9th day demonstrated a sufficient arbitrarily sphincter closure against irrigation flow.

CONCLUSION

The presented descriptive report demonstrates that natural orifice transurethral radical thulium laser prostatectomy for prostate cancer is feasible and safe. Potential candidates include older patients with low-risk cancers and urinary obstruction. Further prospective reports are necessary to evaluate functional and oncological outcome for this innovative technique.

Classification of the distribution of cavernous nerve fibers around the prostate by intraoperative electrical stimulation during laparoscopic radical prostatectomy

We investigated the distribution of cavernous nerve (CN) fibers around the prostate by electrical nerve stimulation during laparoscopic radical prostatectomy to classify the distribution of the CN fibers. Electrical stimulation was performed on 30 consecutive patients with localized prostate cancer; middle of the neurovascular bundle (NVB, point A), base of the NVB (point B), the rectal wall 1 cm posterolateral to the NVB (point C) and the lateral aspect of the prostate (point D). We measured the intraurethral pressure at the midportion to detect the changes in intracavernosal pressure. The mean maximum changes were 10.5 ± 7.9, 11.6 ± 8.8, 9.6 ± 7.4 and 6.7 ± 7.0 cm H(2)O at points A, B, C and D, respectively. The patterns of CN fiber distribution were divided into four groups: type 1 (23%), the bundle corresponding to the NVB; type 2 (7%), the bundle from the rectal wall to the prostate; type 3 (27%), the plate including NVB and posterolateral to NVB; and type 4 (43%), the plate between the rectal wall posterolateral to the NVB and the lateral aspect of the prostate. Distribution of the CNs in a bundle-like formation was considered to account for 30%, whereas a plate-like formation accounted for 70%. Understanding these four patterns of CN fiber distribution should facilitate accurate CN-sparing radical prostatectomy.

Radical prostatectomy: evolution of surgical technique from the laparoscopic point of view

PURPOSE

To review the literature and present a current picture of the evolution in radical prostatectomy from the laparoscopic point of view.

MATERIALS AND METHODS

We conducted an extensive Medline literature search. Articles obtained regarding laparoscopic radical prostatectomy (LRP) and our experience at Institut Montsouris were used for reassessing anatomical and technical issues in radical prostatectomy.

RESULTS

LRP nuances were reassessed by surgical teams in order to verify possible weaknesses in their performance. Our basic approach was to carefully study the anatomy and pioneer open surgery descriptions in order to standardized and master a technique. The learning curve is presented in terms of an objective evaluation of outcomes for cancer control and functional results. In terms of technique-outcomes, there are several key elements in radical prostatectomy, such as dorsal vein control-apex exposure and nerve sparing with particular implications in oncological and functional results. Major variations among the surgical teams' performance and follow-up prevented objective comparisons in radical prostatectomy. The remarkable evolution of LRP needs to be supported by comprehensive results.

CONCLUSIONS

Radical prostatectomy is a complex surgical operation with difficult objectives. Surgical technique should be standardized in order to allow an adequate and reliable performance in all settings, keeping in mind that cancer control remains the primary objective. Reassessing anatomy and a return to basics in surgical technique is the means to improve outcomes and overcome the difficult task of the learning curve, especially in minimally access urological surgery.

Antitumor activity of BIBF 1120, a triple angiokinase inhibitor, and use of VEGFR2+pTyr+ peripheral blood leukocytes as a pharmacodynamic biomarker in vivo

PURPOSE

BIBF 1120 is a potent, orally available triple angiokinase inhibitor that inhibits VEGF receptors (VEGFR) 1, 2, and 3, fibroblast growth factor receptors, and platelet-derived growth factor receptors. This study examined the antitumor effects of BIBF 1120 on hepatocellular carcinoma (HCC) and attempted to identify a pharmacodynamic biomarker for use in early clinical trials.

EXPERIMENTAL DESIGN

We evaluated the antitumor and antiangiogenic effects of BIBF 1120 against HCC cell line both in vitro and in vivo. For the pharmacodynamic study, the phosphorylation levels of VEGFR2 in VEGF-stimulated peripheral blood leukocytes (PBL) were evaluated in mice inoculated with HCC cells and treated with BIBF 1120.

RESULTS

BIBF 1120 (0.01 μmol/L) clearly inhibited the VEGFR2 signaling in vitro. The direct growth inhibitory effects of BIBF 1120 on four HCC cell lines were relatively mild in vitro (IC(50) values: 2-5 μmol/L); however, the oral administration of BIBF 1120 (50 or 100 mg/kg/d) significantly inhibited the tumor growth and angiogenesis in a HepG2 xenograft model. A flow cytometric analysis revealed that BIBF 1120 significantly decreased the phosphotyrosine (pTyr) levels of VEGFR2(+)CD45(dim) PBLs and the percentage of VEGFR2(+)pTyr(+) PBLs in vivo; the latter parameter seemed to be a more feasible pharmacodynamic biomarker.

CONCLUSIONS

We found that BIBF 1120 exhibited potent antitumor and antiangiogenic activity against HCC and identified VEGFR2(+)pTyr(+) PBLs as a feasible and noninvasive pharmacodynamic biomarker in vivo.