Long-Term Functional and Oncological Outcomes of Patients Undergoing Sural Nerve Interposition Grafting during Robot-Assisted Laparoscopic Radical Prostatectomy

Nerve graft for erectile dysfunction after radical prostatectomy: animal study and clinical data-a narrative review

Introduced in the late 1990s, nerve grafting, particularly with sural and genitofemoral nerves, aims to enhance erectile function recovery when neurovascular bundles cannot be preserved following radical prostatectomy. Over the past three decades, researchers have conducted numerous animal and clinical studies to explore the application and clinical effectiveness of this method, with the hope of benefiting patients suffering from erectile dysfunction after radical prostatectomy. Animal studies have demonstrated the potential of various grafting materials, including autologous nerve and vein grafts, and bioengineered grafts, in promoting nerve regeneration and erectile function recovery. Clinical studies, especially those focusing on sural and genitofemoral nerve grafts, have shown mixed results with varied success rates due to methodological weaknesses and small sample sizes. This review thoroughly incorporates current data, explores emerging nerve grafting methods, demonstrates the complexity of nerve grafting outcomes, and emphasizes the necessity for continuous research, including multi-institutional randomized controlled trials, to establish standardized protocols and optimize patient selection for nerve grafting in the management of erectile dysfunction after radical prostatectomy.

Spider silk erectile nerve reconstruction in robot-assisted radical prostatectomy: a first-in-men feasibility analysis

PURPOSE

To investigate the safety and feasibility of spider silk interposition for erectile nerve reconstruction in patients undergoing robotic radical prostatectomy (RARP).

METHODS

The major-ampullate-dragline from Nephila edulis was used for spider silk nerve reconstruction (SSNR). After removal of the prostate with either uni- or bilateral nerve-sparing, the spider silk was laid out on the site of the neurovascular bundles. Data analysis included inflammatory markers and patient reported outcomes.

RESULTS

Six patients underwent RARP with SSNR. In 50% of the cases, only a unilateral nerve-sparing was performed, bilateral nerve-sparing could be performed in three patients. Placement of the spider silk conduit was uneventful, contact of the spider silk with the surrounding tissue was mostly sufficient for a stable connection with the proximal and distal ends of the dissected bundles. Inflammatory markers peaked until postoperative day 1 but stabilized until discharge without any need for antibiotic treatment throughout the hospital stay. One patient was readmitted due to a urinary tract infection. Three patients reported about erections sufficient for penetration after three months with a continuous improvement of erectile function both after bi- and unilateral nerve-sparing with SSNR up to the last follow-up after 18 months.

CONCLUSION

In this analysis of the first RARP with SSNR, a simple intraoperative handling without major complications was demonstrated. While the series provides evidence that SSNR is safe and feasible, a prospective randomized trial with long-term follow-up is needed to identify further improvement in postoperative erectile function due to the spider silk-directed nerve regeneration.

Neuroprotective and Nerve Regenerative Approaches for Treatment of Erectile Dysfunction after Cavernous Nerve Injury

Erectile dysfunction (ED) is a significant cause of reduced quality of life in men and their partners. Cavernous nerve injury (CNI) during pelvic surgery results in ED in greater than 50% of patients, regardless of additional patient factors. ED related to CNI is difficult to treat and typically poorly responsive to first- and second-line therapeutic options. Recently, a significant amount of research has been devoted to exploring neuroprotective and neuroregenerative approaches to salvage erectile function in patients with CNI. In addition, therapeutic options such as neuregulins, immunophilin ligands, gene therapy, stem cell therapy and novel surgical strategies, have shown benefit in pre-clinical, and limited clinical studies. In the era of personalized medicine, these new therapeutic technologies will be the future of ED treatment and are described in this review.

Interpositional Nerve Grafting of the Prostatic Plexus after Radical Prostatectomy

Background:

Injury to the prostatic plexus may occur during radical prostatectomy even with the use of minimally invasive techniques. Reconstruction of these nerves by interpositional nerve grafting can be performed to reduce morbidity. Although the feasibility of nerve reconstruction has been shown, long-term functional outcomes are mixed, and the role of nerve grafting in these patients remains unclear.

Methods:

A retrospective study was performed on 38 consecutive patients who underwent immediate unilateral or bilateral nerve reconstruction after open prostatectomy. Additionally, 53 control patients who underwent unilateral, bilateral, or non–nerve-sparing open prostatectomy without nerve grafting were reviewed. Outcomes included rates of urinary continence, erections sufficient for sexual intercourse, and ability to have spontaneous erections. Analysis was performed by stratifying patients by D’Amico score and laterality of nerve involvement.

Results:

Unilateral nerve grafting conferred no significant benefit compared with unilateral nerve-sparing prostatectomy. Bilateral nerve-sparing patients demonstrated superior functional outcomes compared with bilateral non–nerve-sparing patients, whereas bilateral nerve-grafting patients displayed a trend toward functional improvement. With increasing D’Amico score, there was a trend toward worsening urinary continence and erectile function regardless of nerve-grafting status.

Conclusions:

In the era of robotic prostatectomy, interpositional nerve reconstruction is not a routine practice. However, the substantial morbidity experienced in patients with bilateral nerve resections remains unacceptable, and therefore, nerve grafting may still improve functional outcomes in these patients. Further investigation is needed to improve the potential of bilateral nerve grafting after non–nerve-sparing prostatectomy.

Surgical management of prostate cancer

Surgery remains a mainstay in the management of localized prostate cancer. This article addresses surgical aspects germane to the management of men with prostate cancer, including patient selection for surgery, nerve-sparing approaches, minimization of positive surgical margins, and indications for pelvic lymph node dissection. Outcomes for men with high-risk prostate cancer following surgery are reviewed, and the present role of neoadjuvant therapy before radical prostatectomy is discussed. In addition, there is a review of the published literature on surgical ablative therapies for prostate cancer.

Emerging issues in peripheral nerve repair

It is today widely acknowledged that nerve repair is now more than a matter of perfect microsurgical reconstruction only and that, to further improve clinical outcome, the involvement of different scientific disciplines is required. This evolving reconstructive/regenerative approach is based on the interdisciplinary and integrated pillars of tissue engineering such as reconstructive microsurgery, transplantation and biomaterials. In this paper, some of the most promising innovations for the tissue engineering of nerves, emerging from basic science investigation, are critically overviewed with special focus on those approaches that appear today to be more suitable for clinical translation.

Robotic-assisted radical prostatectomy in 2010

This article reviews the current status of robotic-assisted radical prostatectomy (RARP) with outcome analysis. The published English literature (PubMed) database was searched extensively for major publications and large series on RARP. The search was carried out over the preceding 3-year period. Selected series were then reviewed, summarized and analyzed for their salient features. A literature search yielded 19 major publications on RARP in the preceding 2 years. A review of the current RARP literature (2006-2009) of multi-institutional cases of RARP demonstrated a mean operating room time, blood loss, hospital stay, positive surgical margin rate and perioperative-complication rate of approximately 194 min, 196 ml, 1.43 days, 25.7% and 5.83 %, respectively (based on the analysis of data using central tendency measures [mean]). The overall potency and continence rates were 73.6 and 87.1%, respectively (based on analysis of the published and reported data). All RARP cases were performed with the use of da Vinci robotic system (Intuitive Surgical, CA, USA). It is expected that in 2010 close to 70% of radical prostatectomies in the USA will be performed with robotic assistance. The patient and surgeon appeal for RARP continues to expand exponentially. It seems pertinent to conclude that increasing experience with RARP may reduce the incidence of positive surgical margins and will improve the functional outcome, which is the challenge at this point in time. Although the early cancer control and intermediate follow-up on functional outcome with RARP appears to be convincing and favorable, the long-term ( approximately 10 years) data are still awaited.

Interposition nerve grafting during radical prostatectomy: cumulative review and critical appraisal of literature

In 1997, the first report of sural nerve interposition grafting during radical prostatectomy was published in Urology. The favorable findings in this initial pilot study generated numerous follow-up reports that have demonstrated conflicting and contradictory outcomes. Certainly, controversy exists regarding the true benefit of nerve grafting. This review will objectively and critically summarize the salient literature, discuss evolving techniques, and offer insight into the future of interposition grafting in the current era of clinically localized prostate cancer and robotic prostatectomy.