An updated approach to incremental nerve sparing for robot‐assisted radical prostatectomy

Abstract

A.M. and S.C. contributed equally to this work ObjectivesTo update the algorithm for performing incremental nerve sparing (NS) using our multiparametric magnetic resonance imaging (mpMRI)-based nomogram. Patients and methodsWe applied the coefficients of the nomogram to the observations extracted from our population of patients who underwent robot-assisted radical prostatectomy between February 2014 and October 2015 and who received preoperative mpMRI. The information considered were PSA level, highest side-specific biopsy Gleason grade group, highest ipsilateral percentage core involvement with the highest Gleason grade group, and extracapsular extension (ECE) on mpMRI. The nomogram-derived probability [P (%)], after internal validation, was used as the independent variable on a classification tree to identify the most significant thresholds for ECE prediction. Incremental NS was performed as follows: Grade 1 NS: intrafascial dissection between the peri-prostatic veins and the pseudocapsule of the prostate; Grade 2 NS: inter-fascial dissection along the perivenous plane; Grade 3 NS: inter-fascial dissection through the outer compartment of the lateral prostatic fascia; Grade 4 NS: extrafascial dissection. ResultsData from 561 patients were considered, and 829 prostatic lobes with biopsy-documented tumour were analysed. Overall, 142 lobes presented ECE that was focal in 27 (19%) cases. The classification tree identified four risk categories. In the low-[P (%) ≤10], intermediate-[P (%) 10-21], high [P (%) 21-73] and very-high-risk [P(%) >73] groups, the ECE rates were 3.3%, 16%, 61.6% and 90%, respectively. Amongst those, ECE was focal in 41.7%, 31.7%, 7.9% and 0%, respectively. ConclusionWe suggest that Grade 1 NS (intrafascial) should be performed in the low-risk group. The inter-fascial approach, namely grades 2 and 3 NS, should be performed in the intermediate-and high-risk categories, respectively. Grade 4 NS (extrafascial) should be performed in the very-high-risk group. The current algorithm yields a better accuracy than the previous one; however, prospective validation is warranted.

<p>Changes in risk-group stratification of patients undergoing radical prostatectomy at the Southern Alberta Institute of Urology over time</p>

“…Though we strongly feel that pathological confirmation is a diagnostic gold standard and should be recommended in all instances prior to surgery, an RP in these patients may be considered. Finally, advances in robotic nerve-sparing RP have led to improved functional outcomes while maintaining oncological control in properly selected patients 16. However, despite the reduced morbidity of these techniques, surgery is never without risk.…”

“…Finally, advances in robotic nerve-sparing RP have led to improved functional outcomes while maintaining oncological control in properly selected patients. 16 However, despite the reduced morbidity of these techniques, surgery is never without risk. Regardless of the surgical technique and degree of nerve sparing, RP carries the risk of significant consequences, both functional (eg, incontinence, erectile dysfunction) and perioperative (eg, deep-vein thrombosis, pulmonary embolism, myocardial infection).…”

Comprehensive approach for preserving cavernous nerves and erectile function after radical prostatectomy in the era of robotic surgery

“…53,54 Martini et al reported an algorithm for carrying out graded nerve-sparing procedures using their own nomogram. 55,56 The nomogram consisted of several parameters; that is, preoperative PSA values, Gleason biopsy grade, maximum percentage of tumor in the biopsy core with the highest Gleason score and the findings of extracapsular extension defined by multiparametric magnetic resonance imaging. 55,56 The patients were divided into four risk groups; that is, low-, intermediate-, high-and very high-risk groups, based on the probability values of side-specific extracapsular extension of the prostate calculated by the aforementioned nomogram.…”

“…55,56 The patients were divided into four risk groups; that is, low-, intermediate-, high-and very high-risk groups, based on the probability values of side-specific extracapsular extension of the prostate calculated by the aforementioned nomogram. 55,56 They suggested that graded nerve-sparing procedures should be carried out according to this risk grouping.…”

“…Martini et al . reported an algorithm for carrying out graded nerve‐sparing procedures using their own nomogram 55,56 . The nomogram consisted of several parameters; that is, preoperative PSA values, Gleason biopsy grade, maximum percentage of tumor in the biopsy core with the highest Gleason score and the findings of extracapsular extension defined by multiparametric magnetic resonance imaging 55,56 .…”