Satomi Kawamoto MD

The Russell H. Morgan Department of Radiology and Radiological Science Department of Urology, Johns Hopkins Medical Institutions

Robot-assisted laparoscopic radical prostatectomy is a minimally invasive prostate surgery for localized prostate cancer using the daVinci robotic system (Intuitive Surgical, Sunnyvale, Calif). There has been evolution of open radical prostatectomy to laparoscopic prostatectomy, to robot-assisted prostatectomy in recent years [1]. Robotic systems enhance surgeons technical abilities and offer the potential more precise surgical technique [2]. Since it was first described in 2001 [3, 4] robot-assisted radical prostatectomy is gaining acceptance and popularity among urologists [5].

Robot-assisted laparoscopic radical prostatectomy provides several advantages over open and laparoscopic prostatectomy such as precise dissection through improved instrument control with articulating tips, 3-D vision and magnified view, intuitive eye-hand coordination, motion scaling and filter of tremor [5]. With laparoscopic approaches, a hospital stay of only 1 day has become routine in many centers [6]. Good results with urinary continence and potency after robot-assisted laparoscopic radical prostatectomy have been reported [7, 8], although whether continence and/or potency are better with a laparoscopic/robotic-assisted approach compared with open surgery in expert hands is uncertain [1]. Surgical margins are comparable to those with open approaches [9] and are partly influenced by surgical technique and experience [1].

For laparoscopic radical prostatectomy, the majority of complications are urologic. The most common complication is anastomotic leak which occurred in approximately 10% of patients [10]. Following robot-assisted laparoscopic radical prostatectomy, the reported incidence of postoperative urethrovesical anastomotic urinary leak was 8.6 to 13.6% [11, 12], and it can be associated with intraperitoneal leak when transperitoneal approach is used.

The purposes of this exhibit are to analyze and illustrate the pattern of anastomotic leak after robot-assisted laparoscopic radical prostatectomy on MDCT cystography and to review and illustrate key surgical techniques of robot-assisted laparoscopic radical prostatectomy to explain the mechanism of the intraperitoneal urine leak. Incidence and clinical significance of anastomotic leak after robot-assisted laparoscopic radical prostatectomy were also reviewed.

The da Vinci surgical system

• The da Vinci surgical system comprises three components: a surgeon’s console, a patient-side robotic cart with 4 arms manipulated by the surgeon (the central arm positions the binocular endoscope camera, and three to manipulate multijoint robotic arms), and a high-definition 3D vision system. Multijoint robotic arms are introduced into the body through cannulas. The system is controlled by the surgeon who is seated on the operative console, a few feet away from the patient [2]. The device senses the surgeon’s hand movements and translates them electronically into scaled-down micro-movements to manipulate the tiny proprietary instruments. It also detects and filters out any tremors in the surgeon's hand movements, so that they are not duplicated robotically. The instruments allow 7 degrees of liberty (degree of excursion) in their movement, simulating the human hand [2]. The camera used in the system consists of two high resolution fiber optic cameras, and provides a true stereoscopic view of the operative field with 10-12 fold magnification transmitted to a surgeon's console.
• The da Vinci System is FDA cleared for a variety of surgical procedures including urologic surgical procedures, general laparoscopic surgical procedures, gynecologic laparoscopic surgical procedures, general throacoscopic surgical procedures, and thoracoscopically assisted cardiotomy procedures, and is used in more than 800 hospitals in the worldwide.

There are two approaches of robot-assisted laparoscopic radical prostatectomy; (1) transperitoneal and (2) extraperitoneal approaches. For transperitoneal approach, pneumoperitoneum is initially achieved, and a port and the laparoscope are introduced for initial abdominal inspection. Four additional trocars are then placed. The extraperitoneal space - Retizius (retropubic) space is entered through an inverted U-shaped incision in the parietal peritoneum superior to the bladder to include the urachus and laterally to medial umbilical ligaments. With the Montsouris technique [4], the vas deference and seminal vesicles are dissected retrovesically through an incision of the peritoneum overlying the vas deferens before further dissection of the prostate gland. With this technique, two routes of interaperitoneal communication (anterior to the bladder, and posterior to the bladder) from the uretrovesical anastomosis are made. Alternative to Montsouris technique, the seminal vesicles may be dissected after separation of the prostate from the posterior bladder neck.

The use of transperitoneal or extraperitoneal approach for laparoscopic or robot-assisted laparoscopic prostatectomy is largely a matter of surgeon preference, and there is no consistently demonstrated advantage for either approach [1]. However, extraperitoneal approach helps to confine any urine leak that may occur from the vesicourethral anastomosis within the extraperitoneal space [1].

CT cystography technique

• CT cystography were performed with 64-slice multidetector CT scanners while the balloon tipped Foley catheter was still in place. Noncontrast CT of the pelvis was initially performed, then scan at full bladder was performed after 150-250 ml of diluted sterile contrast material (30 cc of iohexol (Omnipaque 350; GE Healthcare, Princeton, NJ) in a 500 cc bag of normal saline was dripped under gravity into the empty bladder. Scan after emptying the bladder with draining contrast material through the Foley catheter was then obtained. Detector collimation settings of 16 x 0.75 mm or 64 x 0.6 mm were used.
• The data were reconstructed at 0.75 mm slice thickness at 0.5 mm intervals for multiplanar reformation and three dimensional (3D) imaging with soft tissue algorithm. For diagnostic reading, 3 mm or 5 mm slice thickness and 3 mm or 5 mm reconstruction intervals were used.

Extraperitoneal anastomotic leak

• On CT cystography, the site and extent of leak is easily assessed. For extraperitoneal leak, contrast material extending from the vesicourethral anastomosis confines to the extravesical space (Figure 1). When pelvic fluid collection or hematoma is seen on CT, CT cystography can demonstrate presence or absence of communication of anastomotic leak to pelvic fluid collection or hematoma (Figures 2 and 3). Anastomotic leak may be seen in the anterior or posterior aspect of the anastomosis.

Extraperitoneal anastomotic leak

Left: Illustration depicting sagittal section through pelvis, showing retrovesicle and tretropubic space(A). Illustrations, (1, 2, 3.) showing vesicourethral anastomosis.
Right: Illustration depicting anterior leak at vesicourethral anastomosis. Sagittal section shows leak contained in the extraperitoneal space.

Extraperitoneal anastomotic leak

Figure 1. Status post robot-assisted laparoscopic prostatectomy for prostate cancer (pT2bN0Mx, Gleason 7 adenocarcinoma). (a) Fluoroscopic cystogram was performed 13 days after surgery because of recurrent postoperative ileus. It demonstrates moderate extraperitoneal leak within the pelvis. No clear intraperitoneal leak is detected. (b) Axial CT csytogram at the superior aspect of the bladder obtained 4 weeks after surgery shows moderate ascites within the pelvis. (c) Axial and (d) sagittal MPR CT cystograms obtained 4 weeks after surgery show persistent but decrease in size of extraperitoneal leak from the anterior aspect of the anastomosis. The patient was readmitted and treated conservatively. It was felt that undetected intraperitoneal leak that was not detected on the initial cystogram may have lead to a peritonitis causing a recurrent ileus.

Extraperitoneal anastomotic leak

Figure 2. Status post robot-assisted laparoscopic radical prostatectomy (pT2bNxMx, Gleason 7 adenocarcinoma). The patient experienced episodes of leaking urine around Foley catheter with no drainage via Foley catheter. CT cystography obtained 12 days after surgery. (a) Axial noncontrast CT shows moderate sized radiodense fluid collection posterior to the bladder, consistent with hematoma (asterisk). (b) Axial, (c) lateral, and (d) anterior volume rendered CT cystograms show thick-walled bladder, but there is no evidence of anastomotic leak.

Extraperitoneal anastomotic leak

Figure 3. Status post robot-assisted laparoscopic radical prostatectomy (pT2N0Mx, Gleason 6 adenocarcinoma). The patient had abdominal pain after Foley catheter removal, and outside CT showed pelvic fluid collections. CT cystography performed 20 days after surgery. (a) Noncontrast axial CT of the pelvis shows fluid collections anterior and posterior to the bladder. (b) Axial CT csytogram at the level of the vesicourethral anastomosis shows leak from the left posterior aspect of the anastomosis (arrow). (c) Axial CT csytogram above the level of the vesicourethral anastomosis shows contrast accumulation within pelvic fluid collections anterior and posterior to the bladder (asterisk). (d) Lateral volume rendered CT cystogram shows contrast leak from the posterior aspect of the anastomosis, accumulating in the posterior pelvic collection.

Intraperitoneal anastomotic leak

• Intraperitoneal anastomotic leak from vesicourethral anastomosis is an uncommon complication after robot-assisted laparoscopic radical prostatectomy. In patients with intraperitoneal leak, precontrast CT usually shows ascites (Figure 4). On CT cystography, contrast material from the anastomotic leak extending into the peritoneal space is easily detected. Anastomotic leak may arise from the anterior aspect of the anastomosis (Figs 4-6) or from the posterior aspect of the anastomosis (Figs 7-8), and communicate with the peritoneal space. Typically, in our experience, patients with intraperitoneal leak were found early postoperative days (average 2.3 days) when CT cystography was performed due to clinically suspected anastomotic leak. Most patients with intraperitoneal leak were treated conservatively with a Foley catheter kept in place, and follow-up imaging often shows gradual resolution of anastomotic leak without further intervention.

Intraperitoneal anastomotic leak

Illustration depicting posterior leak at vesicourethral anastomosis. Sagittal section shows comunication between the retrovesicle space and peritoneal space.

Intraperitoneal anastomotic leak

Figure 4. Status post robot-assisted laparoscopic radical prostatectomy (pT2N0Mx, Gleason 6 adenocarcinoma). Urine leak was clinically suspected because of rising creatinine and increase in drain via Davol drain. CT cystography performed 2 days after surgery. (a) Axial noncontrast CT shows moderate ascites. (b) Axial and (c) anterior volume rendered CT cystograms show intraperitoneal leak. (d) Lateral volume rendered and (e) axial CT cystograms show contrast leak from the anterior aspect of the anastomosis (arrow), extending into the peritoneal space indicating intraperitoneal leak. The patient’s condition was improved with conservative management, and the patient was discharged. (f) Follow-up fluoroscopic cystogram performed 18 days after surgery demonstrates decrease in size of leak confined to the extraperitoneal pelvis. No intraperitoneal leak is detected.

Intraperitoneal anastomotic leak

Figure 5. Status post robot-assisted laparoscopic radical prostatectomy (pT2N0Mx, Gleason 6 adenocarcinoma). Urine leak was clinically suspected because of rising creatinine, high output from the drain and low output from a Foley catheter. CT cystography performed 2 days after surgery. (a) Sagittal MPR and (b) axial CT cystograms show leak from the anterior aspect of the anastomosis (arrow) extending to the peritoneal space. (c) Axial and (d) anterior MPR CT cystograms show contrast material within the peritoneal space indicating intraperitoneal leak. The patient’s condition was improved with conservative management, and the patient was discharged.

Intraperitoneal anastomotic leak

Figure 6. Status post robot-assisted laparoscopic radical prostatectomy (pT2N0Mx, Gleason 6 adenocarcinoma). Urine leak was clinically suspected because of abdominal pain, rising creatinine, high output from a drain and low output from a Foley catheter. CT cystography performed 3 days after surgery. (a) Lateral volume rendered and (b) axial CT cystograms show leak from the anterior aspect of the anastomosis (arrow) extending to the peritoneal space. (c) Axial and (d) anterior volume rendered CT cystograms show contrast material within the peritoneal space indicating intraperitoneal leak. The patient’s condition was improved with conservative management, and the patient was discharged.

Intraperitoneal anastomotic leak

Figure 7. Status post robot-assisted laparoscopic radical prostatectomy (pT2N0Mx, Gleason 8 adenocarcinoma). Urine leak was clinically suspected because of high output from a drain and abdominal pain. CT cystography obtained 6 days after surgery. (a) Noncontrast CT at the level of urethrovesical anastomosis shows small fluid collection posterior to the anastomosis. (b) sagittal MPR and (c) axial CT cystograms show leak from the posterior aspect of the anastomosis (arrow) which accumulates in the pelvic fluid collection (asterisk), and extends to the peritoneal space. (d) Anterior volume rendered CT cystogram shows contrast material within the peritoneal space indicating intraperitoneal leak. The patient’s condition was improved with conservative management, and the patient was discharged. (e) Follow-up fluoroscopic cystography 16 days after surgery and (f) 44 days after surgery shows decrease in size of leak (arrow) confined to the extraperitoneal space.

Intraperitoneal anastomotic leak

Figure 8. Status post robot-assisted laparoscopic radical prostatectomy (pT2N0Mx, Gleason 7 adenocarcinoma). Urine leak was clinically suspected because of high drain outputs, low Foley outputs, elevated creatinine, and abdominal pain on post op day 1. CT cystography performed 1 day after surgery. (a) Lateral volume rendered and (b) axial CT cystograms show leak from the posterior aspect of the anastomosis (arrow) extending to the peritoneal space. (c) axial and (d) anterior volume rendered CT cystogram show contrast material within the peritoneal space indicating interaperitoneal leak. The patient underwent exploration and reanastomosis. The patient recovered without complication after reanastomosis.

The reported rate of anastomotic leak after open radical prostatectomy is quite varied ranging from 3.9% to 23% in the prior studies [14, 15]. For laparoscopic radical prostatectomy, the reported rate of anastomotic leak occurred in approximately 10% to 17% [10, 16]. Similar complication rates have been reported after robot-assisted laparoscopic radical prostatectomy.

Patil et al. [12] reported 287 (8.6%) of 3327 patients who had robot- assisted laparoscopic prostatectomy had a detectable anastomotic leak on cystography. They also classified anastomotic leaks in patients undergoing robot-assisted radical prostatectomy into three grades based on the gravity cystography [12]. Cystography was obtained 7 days after robotic prostatectomy after instilling 125 to 250 ml of iodinated contrast medium; grade I, extraperitoneal within 6 cm of the urethrovesical anastomosis; grade II, extraperitoneal extending to the side-wall >6 cm from the anastomosis; grade III, intraperitoneal. Among them, 179 (62.4%) was grade I, 84 (29.3%) were grade II, and 24 (8.4%) were grade III. Of the patients with a detectable anastomotic leak, 70% were continent within 3 months and 94% had no involuntary urinary leakage at 1 year. Eight of grade II or II patients (2.8% of 287 patients) in this study required a secondary intervention to correct bladder neck contracture. They concluded that the presence of anastomotic leak might delay the time to continence, but no adverse effect on long-term urinary control, and quantifying the gradation of leakage might provide the prognostic information about patients at risk for future interventions [12].

In our experience, among 882 patients who underwent robot-assisted laparoscopic prostatectomy between 2003 and May 2009, 314 patients (35.6%) underwent postoperative imaging studies to evaluate anastomotic leak including 8 patients who underwent CT cystography. Anastomotic leak was found in 55 patients including 6 patients on CT cystography. This accounted for 55 of 314 patients who had imaging studies (17.5%), and 6.2% of all 882 patients. Leak of contrast material was limited in extraperitoneal pelvic space in 50 patients. Intraperitoneal leak was documented in 5 patients (0.6%) of our patients, and only one of 5 patients required repair of anastomosis.

Anastomotic leak after robot-assisted laparoscopic prostatectomy is mostly limited to extraperitoneal pelvic space, which is usually transient and requires no further intervention. Rarely, intraperitoneal leak may occur after robot-assisted laparoscopic prostatectomy. Most patients with intraperitoneal leak were treated conservatively. MDCT cystography is a fast and accurate method to detect anastomotic leak and to evaluate extent of extraperitoneal and intraperitoneal leak after RALRP.

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