Real-time transrectal ultrasonography during laparoscopic radical prostatectomy

We describe the technical aspects of real-time transrectal ultrasound (TRUS) monitoring and guidance during laparoscopic radical prostatectomy (LRP). Furthermore, we describe the TRUS visualized anatomy of periprostatic structures during LRP.

In 25 consecutive patients undergoing transperitoneal LRP, baseline preoperative, real-time intraoperative and immediate postoperative TRUS evaluations were performed. To define periprostatic anatomy precisely TRUS measurements were obtained with specific reference to the neurovascular bundle (NVB), prostate apex, membranous urethra, bladder neck, rectal wall and any cancer nodule. Conventional gray scale, power Doppler, harmonic imaging and 3-dimensional ultrasound functions were used.

Real-time TRUS navigation facilitated 3 technical aspects of LRP. 1) It identified the correct plane between the posterior bladder neck and prostate base, allowing quick laparoscopic identification of the vasa and seminal vesicles. 2) It identified the occasional, difficult to see distal protrusion of the prostate apex posterior to the membranous urethra, thus enhancing apical dissection with negative margins. 3) It provided visualization of any hypoechoic nodule abutting the prostate capsule, alerting the laparoscopic surgeon to perform wide dissection at that location. TRUS measured various anatomical parameters including i) the mean distance +/-SD between the NVB and the lateral edge of the prostate a) at apex (1.9 +/- 0.9 mm), b) base (2.5 +/- 0.8 mm) and c) tip of seminal vesicle (4.0 +/- 1.6 mm), ii) the dimensions of the NVB a) before (4.5 x 3.9 mm), b) after (4.2 x 3.6 mm) nerve sparing LRP and c) after nonnerve sparing LRP (0.9 x 0.9 mm), iii) arterial blood flow resistive index within NVB a) before (0.83 +/- 0.04), b) after (0.84 +/- 0.03) nerve sparing LRP and c) after nonnerve sparing LRP (0), iv) and the length of membranous urethra a) before (12.2 +/- 1.1 mm) and b) after (11.7 +/- 1.0 mm) surgery. Focal distortion of the prostate surface by an exophytic nodule was visualized on TRUS in 3 patients, necessitating ipsilateral nerve resection at LRP and contributing to negative surgical margins.

This initial experience suggests that real-time intraoperative TRUS guidance may enhance anatomical performance of LRP. This improved understanding of periprostatic anatomy has the potential to improve functional and oncological outcomes. Such corroboration is awaited.