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Ejaculation sparing surgery for Benign Prostatic Enlargement

Dr. Andrea Cocci,
Urology Section, Department of Andrology and Urology, University of Florence

Rodrigo Suarez-Ibarrola,
Department of Urology, Faculty of Medicine, University of Freiburg – Medical Centre, Freiburg, Germany

Dr. Giorgio Ivan Russo,
Department of Urology, Department of Surgery, University of Catania, Catania, Italy

Benign prostatic enlargement (BPE) is a prevalent condition of the aging male that can lead to a range of lower urinary tract symptoms (LUTS) [1, 2]. Moderate to severe LUTS are estimated to affect 30% of men over the age of 50 years and are known to negatively impact mental and physical aspects of health [3]. Furthermore, approximately 25% of men who develop LUTS will require surgical intervention [4].

Over the past three decades research has focused on the development of new surgical strategies to reduce morbidity and complications of conventional surgical procedures, such as transurethral resection of the prostate (TURP) and open prostatectomy (OP), but in most cases overlooking the impact on the patients’ ejaculatory function.

Although TURP remains the treatment reference standard, it carries risks of bleeding, clot retention, urethral stenosis, bladder neck contracture and ejaculatory dysfunction [5]. Despite its significant morbidity and long learning curve, TURP remains today the standard treatment for symptomatic BPE. In recent years, there has been a pursuit to develop minimally invasive therapies with fewer complications, better side-effect profiles and equal efficacy to rival TURP. Laser-based treatment options have reduced perioperative morbidity and allowed size-independent endoscopic enucleation of the prostate.

Thanks to the advent of laser technologies, endoscopic enucleation of the prostate (EEP) techniques have been developed . These mimic an OP, which is achieved endoscopically, using a laser, or a bipolar resector to enucleate the adenoma, imitating the use of the finger during OP, but maintaining minimal invasiveness of TURP. Holmium laser enucleation of the prostate (HoLEP) and thulium laser enucleation of the prostate (ThuLEP) are the most demanded laser EEP (LEEP) techniques. Both determine excellent resolution of LUTS and improvement in voiding parameters, comparable to those of TURP and OP, but with reduced morbidity, catheterization time and hospital stay. Moreover, they allow to treat prostates of virtually all sizes. Reasons for which, EAU Guidelines recommend to resort to OP only in the absence of an EEP system. Despite the well documented advantages of LEEP techniques over TURP and OP, they have not been able to overcome postoperative ejaculatory dysfunction (EjD). The only recommended ejaculation-sparing (ES) procedure today, is the prostatic urethral lift, which consists in the positioning of suture-based implants under cystoscopic guidance, to compress the lateral lobes. Despite being a valid treatment option, especially in elderly and frail patients and despite excellent outcomes on ejaculation, it does not achieve the same micturition improvement of TURP. Moreover, it is only recommended for small prostates (< 70 cc) and it does not remove the hyperplastic tissue. Other novel, minimally invasive, non-ablative surgical techniques such as Aquablation, Rezum, and prostatic artery embolization, despite presenting more favorable outcomes on ejaculation compared to TURP, are still considered “under investigation” by EAU Guidelines, due to the lack of randomized controlled trials, with a long-term follow-up, investigating their safety and efficacy. Before the ‘90 s ejaculation was thought to be a 4-phase process, which consisted of:

  1. Erection.
  2. Emission of semen into the prostatic urethra, closed between the internal sphincter (bladder neck) and the external sphincter.
  3. Formation of a pressure chamber inside the prostatic urethra.
  4. Expulsion of semen through the external sphincter. According to this theory, loss of ejaculation after endoscopic surgery was and is still attributed by many to the removal of the internal sphincter, causing retrograde ejaculation.

However, evidence on ejaculation physiology has demonstrated the importance of the tissues surrounding the veru montanum, rather than the bladder neck, for outward ejaculation. Dynamic transrectal ultrasonography (TRUS) has shown how, just before ejaculation, the veru montanum undergoes a caudal shift, making contact with the anterior wall of the urethra, allowing the antegrade progression of semen, which is emitted into the inframontanal urethra and expelled, almost simultaneously, through the external sphincter. No accumulation of semen inside the prostatic urethra, and therefore, generation of a high-pressure area was demonstrated. A fundamental role in this process is played by the musculus ejaculatorious, a longitudinal strain of muscle fibres, which originate from around the ejaculatory ducts and extend caudally in the urethral crest, inserting below the urethral sphincter. Contraction of the musculus ejaculatorious could be responsible not only for the emission of semen from the ejaculatory ducts into the prostatic urethra, but also for the correct movement of the veru montanum during ejaculation.

Based on these findings, supramontanal and paracollicular tissue-sparing surgical techniques have been developed.

ES techniques have been applied to TURP and photoselective vaporization of the prostate (PVP) with encouraging results. However, TURP and PVP are currently recommended only for the treatment of small to intermediate size prostates. Considering that LEEP techniques have already proved to be size independent, modify classical ThuLEP surgery, by sparing 1.5 cm of tissue above the veru montanum and two hills of tissue at the apex of the lateral lobes, can be effective in maintaining ejaculation, without compromising micturition improvement.

Recently, aquablation (Aquabeam®, Procept BioRobotics, Redwood Shores, CA, USA) has emerged as a novel minimally invasive water ablation therapy combining image-guidance and robotics for the targeted and heat-free removal of prostatic tissue [6]. Aquablation has shown high levels of efficacy with a potentially decreased risk of side effects in sexual function possibly due to more accurate tissue targeting [7]. One of its potential advantages is the rapid resection time and the robotic standardization of BPE surgery as opposed to free-hand resection in patients with more challenging anatomies such as large prostates and prominent middle lobes. While an increasing number of studies have been performed on the technique, a critical, comprehensive and detailed statistical appraisal is still lacking.

References

1. Faber, K., et al., Image-guided robot-assisted prostate ablation using water jet-hydrodissection: initial study of a novel technology for benign prostatic hyperplasia. J Endourol, 2015. 29(1): p. 63-9.

2. Gravas S, Cornu J.N., Drake M.J. et al. EAU Guidelines on the Management of Non-neurogenic Male LUTS 2018.

3. Gilling, P., et al., Aquablation – image-guided robot-assisted waterjet ablation of the prostate: initial clinical experience. BJU Int, 2016. 117(6): p. 923-9.

4. Gilling, P., P. Anderson, and A. Tan, Aquablation of the Prostate for Symptomatic Benign Prostatic Hyperplasia: 1-Year Results. J Urol, 2017. 197(6): p. 1565-1572.

5. Pimentel, M.A., S.M. Nair, and P.J. Gilling, Aquablation™: Early Clinical Results. Current Bladder Dysfunction Reports, 2016. 11(2): p. 130-133.

6. Taktak, S., et al., Aquablation: a novel and minimally invasive surgery for benign prostate enlargement. Ther Adv Urol, 2018. 10(6): p. 183-188.

7. Gilling, P., et al., WATER: A Double-Blind, Randomized, Controlled Trial of Aquablation® vs Transurethral Resection of the Prostate in Benign Prostatic Hyperplasia. J Urol, 2018. 199(5): p. 1252-1261.

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