Curr Urol Rep (2014) 15:402 DOI 10.1007/s11934-014-0402-9
MINIMALLY INVASIVE SURGERY (V BIRD AND M DESAI, SECTION EDITORS)
Robotic Surgery in Pediatric Urology Jason P. Van Batavia & Pasquale Casale
Published online: 23 March 2014 # Springer Science+Business Media New York 2014
Abstract Minimally invasive laparoscopic procedures for urological diseases in children have proven to be safe and effective, with outcomes comparable to open procedures. Technical advances, including improved instruments and high-definition cameras, have contributed to the expanded role of minimal invasive surgery (MIS) in children. The major drawback to laparoscopy has been the relatively steep learning curve due to the technical difficulties of suturing and the limitations of instrument dexterity and range of motion. Recently, robotic-assisted laparoscopic surgery (RAS) has gained popularity in both adult and pediatric urology. RAS has several advantages over conventional laparoscopic surgery, particularly in the improved exposure via magnified 3dimensional view and simplification of suturing with the increased degree of freedom and movement of the robotic arm. This review discusses the role of RAS in pediatric urology and provides technical aspects of RAS in specific urologic procedures as well. Keywords Robotics . Laparoscopy . Minimally invasive surgery . Pediatrics . Urology
Introduction With the recent advances in equipment and surgical techniques, minimally invasive surgery (MIS) has become an widely accepted and efficient technique in both adults and children. Laparoscopic surgery is associated with minimal morbidity when compared to standard open surgery, and has the advantages of a quicker postoperative recovery, increased magnification, superior cosmetic outcome, less postoperative This article is part of the Topical Collection on Minimally Invasive Surgery J. P. Van Batavia : P. Casale (*) Department of Urology, Columbia University Medical Center, Division of Pediatric Urology, Morgan Stanley Children’s Hospital/NY Presbyterian, New York, USA e-mail: [email protected]
pain, lower analgesic requirements, and shorter hospital stays [1–3]. The major drawback of the pure laparoscopic approach has been the relatively steep learning curve for the procedure given the technical difficulties of suturing and anastomosis. These limitations can be minimized through the use of robotic surgical technology [4–6]. Advantages of Robotic Surgery Since its inception as a military tool for remote surgical care of injured soldiers, and with its subsequent expansion into clinical practice in the late 1990s and 2000s, robotic-assisted surgery (RAS) has gained enormous popularity in adult urology [7]. The daVinci Surgical System (Intuitive Surgical, Sunnyvale, CA, USA) provides the advantages of a novel dual-channel telescope that enhances visualization by providing a highly magnified 3-dimensional (stereoscopic) image that improves hand-eye coordination. Furthermore, this magnified image can be combined with tremor filtration and motion scaling, which allows for delicate motions in small areas, thus enabling much wider adoption of a procedure that would otherwise require advanced laparoscopic expertise. Additionally, robotic technology assists the pediatric surgeon by increasing dexterity and precision of movement with a robotic wrist-like mechanism that allows for up to 90 degrees of articulation and 7 degrees of freedom [8]. The overall benefit over conventional laparoscopy is to reduce the learning curve for intracorporeal suturing and performance of MIS [12]. While robotic surgery was initially thought not feasible in children before adolescence due to the smaller working spaces and large size of the robot, RAS is now in use throughout pediatric urology. Uses in Pediatric Urology The most common procedure performed robotically in pediatric urology is pyeloplasty for ureteropelvic junction obstruction [5]. Utilization of RAS in pediatric urology has recently expanded to include virtually all surgeries performed by the
402, Page 2 of 7
pediatric urologist, particularly ureteral reimplantation as well as both total and partial nephrectomy [6, 9]. Even complex reconstructive urologic procedures have been amenable to the robotic approach, including appendicovesicostomy and bladder augmentation [10, 11]. Although long-term outcome analysis of robotic pediatric urology series has been largely unexplored, the same advantages of laparoscopic over open conventional surgical procedures apply: more rapid recovery, less postoperative pain, less analgesic use, and shorter hospital length of stay [13••].
Important Principles of RAS As with any surgical procedure, RAS requires a unique skill set that must be learned, practiced, and mastered by the pediatric urologist. This includes an understanding of both anatomy and physiology for planning of trocar placement as well as the ability to embrace the technology with its constantly evolving instruments and equipment. The pediatric patient represents a smaller working environment compared to the adult, which can lead to port site conflicts and instrument collisions. Children are also thought to be more sensitive to intra-abdominal pressure, have a higher likelihood of crepitance development, and have less resistant (compliant) abdominal walls. Sakka et al. noted that children 2–6 years of age had significant decreases in cardiac index when initial intra-abdominal pressures of 12 mmHg were used and that these changes reversed upon reducing the pressure to 6 mmHg [14]. Taking these differences into account, the senior author uses working pressures of 6–10 mmHg in infants (0–2 years) and 10–12 mmHg in older children and adolescents [14, 15]. Another important difference between children and adults is the greater incidence of aerophagia and gastric insufflation during anesthesia induction in children, which when combined with the more rapid gastric emptying time seen in children, can lead to rapid insufflation of the entire small bowel. Distended small bowel can present problems during trocar placement and can hinder visualization/access during RAS. To minimize these effects, the authors recommend immediate placement of orogastric or nasogastric tube immediately after endotracheal tube insertion to decompress the stomach. Additionally, the bladder in infants is in a more abdominal location, which increases the risk of bladder injury during trocar insertion. This risk can be minimized by placement of a urethral catheter prior to gaining access. The use of robotic surgery simulators, and what D. Anders Ericsson calls “deliberate practice,” can overcome the limitations of experience gained only in the operating room [16•]. Another critical principle of RAS is mentorship and training under an expert in the field. The mentor is able to both teach the proper skills and techniques as well as address bad habits, which can then be unlearned.
Curr Urol Rep (2014) 15:402
General Techniques Gaining Access The robot has both 8-mm and 5-mm diameter instruments, and the most commonly used camera scope is 12 mm in diameter. Typically, an open-access (Hasson) technique is used first to place the 12-mm camera port. This technique involves opening the skin, fascia, and muscle until the peritoneum is exposed. The peritoneal cavity is then entered and the trocar placed under direct vision. The use of this open technique has been shown to decrease the risk of major vascular injury in large multicenter analyses [17–19]. An alternate approach for the initial trocar placement is to use the Veress needle. The needle itself utilizes a spring-loaded “safety” insert that is designed to prevent iatrogenic visceral injury. The Veress needle is placed blindly into the abdominal cavity, and insufflation occurs through the needle. Proper placement is supported by placement of a saline-filled syringe on the needle. Aspiration should show gas in the syringe, and saline injected into the needle as the syringe is removed should quickly enter the abdomen (the so-called hanging saline drop test). When gas is insufflated via the Veress needle, one should see high flow rates at low pressure. If these findings are not observed, the needle should be withdrawn and placement reattempted before the trocar is inserted. We usually place the camera port in the superior aspect of the umbilicus, although depending on the age and size of the patient, this site may be placed more inferior if it affords better triangulation to the operative organ. The abdomen is insufflated with CO2 at the desired pressure, and the 12-mm, 0-degree telescope is inserted to view the area of insertion for iatrogenic trauma. In addition to the 12-mm camera, a 5-mm endoscope is available, although it is monocular and provides only 2D images. Next, the working trocars (often two separate 5-mm trocars, although 8-mm trocars are available) are inserted under direct vision. For upper urinary tract surgery, the robotic device is docked from the ipsilateral side; for lower urinary tract surgery and orchiopexy, it is docked from the foot of the bed. The robotic instruments are available in both 8-mm and 5–mm sizes, which is determined based on the size of the patient. A fourth arm is available for grasping and retraction. Generally, we utilize Maryland bipolar forceps as a grasper and either monopolar hook device or curved scissors during dissection. The instruments can be changed quickly and easily by the bedside assistant. After appropriate dissection and exposure, the dissecting instruments can be switched to robotic needle drivers (often in both arms) to make suturing easier. As the technology has evolved over time, results have improved and are now nearly identical to open procedures, utilizing 5-0, 6-0, and 7-0 sutures as in open surgeries.
Curr Urol Rep (2014) 15:402
Procedure Nephrectomy Indications for simple nephrectomy include poorly functioning or nonfunctioning kidney secondary to UPJ obstruction, obstructing stone, reflux nephropathy, single-system ectopic ureter, and multicystic dysplastic kidney [20]. Simple nephrectomy may also be utilized for donor nephrectomies, while radical nephrectomy may be performed for renal cell carcinoma and Wilms tumor [21]. Simple nephrectomy can be performed with either conventional laparoscopic or robotic-assisted approaches, but as outlined above, the use of RAS for nephrectomy has several advantages: high-definition three-dimensional images, increased dexterity and range of motion, and gentler learning curve [22]. While both conventional laparoscopic and roboticassisted laparoscopic nephrectomy can be performed using either the transperitoneal or retroperitoneal approach, the transperitoneal procedure is more widely utilized in robotics, especially in the infant population, given the size of the ports and the robotic arms. Ultimately, the choice depends upon the surgeon’s experience and the need for additional procedures such as ureterectomy and/or bladder access. Retroperitoneal Approach Retroperitoneal access is different from the transabdominal approach in both port placement and patient positioning. Ports are placed posteriorly or laterally, depending upon surgeon preference. Given the size of the robotic arms compared with the size of the patient, a posterior approach is more difficult in pediatrics for children 12 years and younger [19]. For access, the first trocar incision is made 15 mm long and 10 mm inferior from the lower border of the tip of the 12th rib. This trocar is fixed with a purse-string suture to make an airtight seal, and the working space is created by gas insufflation dissection. Alternatively, the working retroperitoneal space can be created by utilizing two index fingers of powder-free surgical gloves, which are placed one inside the other and attached to the end of the 5/10-mm trocar sheath. Next, 500 ml of warm saline is instilled through the insufflation channel of the trocar, and after completed dissection, the trocar is reinserted without the balloon. Pneumoretroperitoneum is established using a maximum pressure of 12 mmHg (or alternative pressure if age/weight appropriate) and a 5-mm or 10mm 0-degree telescope is inserted through this first trocar. The two working ports are then placed under direct vision, with the first trocar inserted posteriorly near the costovertebral angle and the second trocar inserted 10 mm above the top of the iliac crest in the anterior axillary line. Care must be taken to avoid transperitoneal insertion of the second working trocar by ensuring that the retroperitoneal working space is fully developed and identifying the deep
Page 3 of 7, 402
surface of the anterior wall muscles before inserting the trocar. Using this access technique, the kidney is approached posteriorly and Gerota’s fascia is incised parallel to the psoas muscle. Next, the perirenal fat is dissected to reveal the lower pole of the kidney, followed by identification of the renal pelvis, which is then mobilized. Ideally, the ureter is located first and can be transected to form a handle that can be used to guide the surgeon to the renal hilum. Transabdominal Approach The transabdominal approach can be performed in one of two ways: with the patient in the supine position with rotation of the table 45 degrees, or with the patient in a modified flank position (contralateral decubitus) with a 60-degree elevation of the flank. The ipsilateral arm can be placed on an elevated armrest in a straight extended or elbow-bent configuration or in a hand-in-pocket position at the patient’s ipsilateral side. First, the camera port is placed in the umbilicus (via either the Hasson or Veress technique), and then the working ports are placed under direct vision. The first working port is placed either midline at a point at least 4 cm above the umbilicus or lateral to the ipsilateral rectus muscle at the subcostal border. The second working port is placed either in the midline at least 4 cm below the umbilicus or in the midclavicular line at the level of the anterior superior iliac spine. In infants, the more cephalad working port should be placed subxiphoid in the midline, and the more caudal working port either as lateral as possible to the rectus muscle or suprapubically. When placing ports suprapubically, caution must be taken to avoid iatrogenic injury, especially to the bladder. The robot is docked over the ipsilateral shoulder, and the procedure is performed as described for laparoscopic approach [23]. Gargollo et al. have described an alternative approach to port placement, termed the HIdES technique, in which the robotic working port, camera port, and 5-mm assistant port are placed below the line of a Pfannenstiel incision. The second working port is then placed infraumbilically [24]. Heminephroureterectomy and Partial Nephrectomy Heminephroureterectomy (HNU) and partial nephrectomy may be indicated in children with duplication anomalies such as nonfunctioning upper pole kidney with ectopic ureter or ureterocele, cystic malformation of upper pole kidney, and nonfunctioning refluxing lower pole kidney [25]. The magnification and high-definition 3D imaging of the robot are particularly advantageous for these children since the upper and lower poles of the kidney are often divided by a clear vascular and anatomic plane that can be visualized. Roboticassisted HNU and partial nephrectomy can also be performed via transperitoneal or retroperitoneal approach in a similar manner to nephrectomy, with identical port placement and initial exposure of the ureters and hilum. The resection of
402, Page 4 of 7
the affected moiety can be accomplished either with the hook or scissors cautery, ultrasonic shears, or bipolar device. Prior to patient positioning, an open-ended ureteral catheter can be placed cystoscopically into the unaffected moiety in order to inject methylene blue after moiety transection to ensure that there is no leakage. For HNU, once the heminephrectomy is complete, the robot typically needs to be re-docked from the foot of the bed for access to the bladder. The senior author prefers the transperitoneal approach because, if bladder access is needed, one can readily turn the robotic instruments to the bladder for repair. Pyeloplasty Pyeloplasty is performed for ureteropelvic junction obstruction (UPJO), which is characterized by a functionally significant impairment of urinary transport. UPJO can be caused by intrinsic obstruction or smooth muscle impairment, anatomical abnormalities (e.g., high ureteral insertion) or extrinsic obstruction (e.g., anteriorly crossing vessel) at the precise junction of the renal pelvis and ureter. Robotic assisted laparoscopic pyeloplasty is performed in a similar manner to conventional laparoscopic pyeloplasty, but with the significant advantage of easier and more precise suturing with the robotic arms and instruments. As with robotic nephrectomy, robotic-assisted pyeloplasty can be performed using a transperitoneal or retroperitoneal approach with the same patient positioning and the same robotic docking as described above. Retroperitoneal Approach With the retroperitoneal approach, the surgeon approaches the kidney from the posterior side. From the posterior side, Gerota’s fascia is identified, and the fascia is incised in a parallel manner to the psoas muscle. Next, the perinephric fat is dissected to expose the lower pole of the kidney from which the renal pelvis can be identified and mobilized, allowing access to the UPJ. The UPJ is minimally dissected from surrounding connective tissue, and special attention must be paid to the anterior surface of the UPJ to identify or confirm the absence of any crossing vessel pathology. Transperitoneal Approach During the transperitoneal approach, the left UPJ is exposed transmesenterically and the right UPJ is exposed with minimal colonic mobilization. While the senior author prefers a transmesenteric approach for access to the left UPJ, alternatively, the colon on the left may be mobilized if the surgeon prefers. If the colon for a left UPJ is mobilized, the surgeon must continue the mobilization medially over the aorta [26]. The surgical procedures follow the same steps as the conventional laparoscopic approach [27]. If the renal pelvis is extremely dilated and/or difficult to access, a hitch stitch can be passed through the abdominal wall and placed through the renal pelvis. The bedside assistant
Curr Urol Rep (2014) 15:402
then places the stitch on traction by lifting both ends of the suture extracorporeally and placing a clamp on both ends just above the skin. This helps to elevate and stabilize the renal pelvis for easier access during incision of the UPJ and reanastomosis. The hitch stich is often helpful if a pyelolithotomy is necessary. After the UPJ is exposed, the pelvis is incised and the ureter is spatulated laterally. Depending upon the type of pyeloplasty to be performed, the renal pelvis, UPJ, and/or ureter can be incised to fit the repair. Reports in the literature have described various laparoscopic and robotic pyeloplasty techniques, including AndersonHynes dismembered pyeloplasty, “Y-V plasty,” and the “bypass pyeloplasty,” in which a side-to-side anastomosis is made between the dilated portion of the ureter just distal to the UPJO and the lower dependent portion of the hydronephrotic renal pelvis [28•, 29]. Choice of dismembered versus nondismembered pyeloplasty is dependent upon surgeon experience and the anatomy of the renal pelvis and ureter. In all pyeloplasties, the anastomosis is performed using a running suture. While a 6-0 monofilament absorbable suture is preferable for the anastomosis, any 5-0 or 6-0 absorbable suture can be used, depending upon the patient’s size. If a ureteral stent is required, a double-pigtail stent can be placed after the posterior wall of the anastomosis is closed. The stent can be placed through the anterior abdominal wall via a 16-gauge angiocatheter. A guide wire is first placed through the angiocatheter and manipulated by the robotic instruments down the ureter in an antegrade fashion. Next, the stent is passed over the guide wire. To confirm proper position of the stent into the bladder, the bladder can be filled with methylene blue so that one can observe the efflux of blue urine when the stent enters the bladder. Alternatively, the ureteral stent can be placed via cystoscopy in a retrograde fashion, with a dangling string to allow removal in the office. Postoperatively, the senior author leaves a urethral catheter overnight, and if a doublepigtail stent is placed, it is removed in 2 to 4 weeks. The results described in the literature show similar success rates for the robotic and open procedures, at around 95 % [13••, 30, 31]. Ureterocalicostomy Robotic ureterocalicostomy can be performed in children with UPJ obstruction and significant lower pole caliectasis or those with an exaggerated intrarenal pelvis. It may also be useful in patients who have failed previous pyeloplasty and have a minimal pelvis [32]. The procedure utilizes the transperitoneal approach, with similar trocar placement as described above for pyeloplasty. If necessary, after colon reflection, the ureter is transected and ligated using absorbable sutures at the level of the renal pelvis. Next, the most dependent lower pole calix is incised using hot scissors with minimal bleeding secondary to the thinned parenchyma of the lower pole system. The ureter is then spatulated and the posterior anastomosis of the ureter with the lower pole calix is performed using 5-0 absorbable suture in a running fashion.
Curr Urol Rep (2014) 15:402
After the posterior anastomosis is complete, the ureteral stent is placed as described above. The anterior anastomosis is performed in an interrupted fashion, which allows visualization and precise alignment of the calix with the ureteral mucosa without tension on the renal parenchyma. The stent is left in place for approximately 6 weeks and removed at the same time as retrograde ureteropyelogram to confirm an intact and healed anastomosis. Ureteroureterostomy Ureteroureterostomy is indicated in children with a duplicated collecting system in which the upper pole ectopic moiety has function. At the beginning of the procedure, all patients undergo cystoscopy with retrograde pyelogram and open-ended ureteral catheter placement into the lower pole. A urethral catheter is then placed and the external portion of the ureteral catheter is secured to the urethral catheter. Both catheters are prepped into the operative field, as access to the ureteral catheter is essential during the robotic portion of the procedure. The senior author utilizes the transperitoneal approach for robotic ureteroureterostomy, with trocar placement similar to that described above for pyeloplasty. The upper pole ectopic ureter is dissected free, transected, and spatulated. The proximal portion of the upper pole ureter is then anastomosed to the lower pole ureter in an end-to-side fashion. The anastomosis is performed with 6-0 absorbable suture in a running fashion. During this portion of the procedure, the open-ended ureteral catheter can be instilled with methylene blue to test the integrity of the anastomosis. The distal upper pole ureteral segment is then dissected and removed all the way to the level of the vagina in girls and the prostate in boys. As the transperitoneal approach affords easy access to the distal ureteral segment for resection, we recommend removing this segment in all children undergoing ureteroureterostomy. Ureteral Reimplantation Open ureteral reimplantation is the established procedure for primary vesicoureteral reflux (VUR). Over the past decade, successful laparoscopic and robotic-assisted laparoscopic ureteral reimplantation has been described via both extravesical and vesicoscopic approach [33–35, 36••]. Indications for reimplantation in children with VUR are controversial, but may include breakthrough urinary tract infection, worsening reflux, and unresolved high-grade reflux with evidence of upper tract scarring/damage. Transvesical Approach For the laparoscopic Cohen procedure using a pneumovesicum, the patient is placed in the supine position with legs apart. The bladder is filled with saline solution via a urethral catheter, and the 12-mm camera port is placed directly into the dome of the bladder through the
Page 5 of 7, 402
midline using an open technique or under direct visualization via a flexible pediatric cystoscope. Next, the bladder wall and skin are secured to the trocar using 3-0 absorbable suture secures. The working ports (8-mm or 5-mm) are inserted at the midclavicular line midway between the umbilicus and pubis, and all ports are secured to the abdominal wall. This stitch is utilized later to close the bladder. To insufflate the bladder, the urethral catheter is attached to suction to drain all saline from the bladder as CO2 is introduced via the port. The robot can then be docked over the patient’s feet. The reimplantation is performed in a manner similar to the open technique, with insertion of a 6-cm segment of a 5Fr feeding tube or 4Fr open-ended ureteral catheter into the ureter. The ureteral stent is secured with 4-0 absorbable suture prior to ureteral dissection. Next, hook or scissors cautery is used to dissect and mobilize the ureters. The submucosal tunnels are formed using the scissors starting from the original hiatus in a cross-trigonal manner to the contralateral side of the trigone [26]. After incision of the mucosa at the site of the new hiatus, the ureter is brought through the submucosal tunnel and ureteral anastomosis performed using 4-0 absorbable anchoring sutures to secure the ureter to the bladder musculature. 5-0 absorbable sutures are used to attach the ureter to the mucosal cuff, and the original hiatal mucosa is closed using a running 5-0 absorbable suture. Upon completion of the reanastomosis, the working ports are removed and the bladder holding stitches are tied down. The fascia at each port site is closed, and a flexible cystoscope is inserted transurethrally to thoroughly inspect the bladder. Finally, a urethral catheter is placed and kept in overnight. It should be noted that this technique is extremely challenging but provides excellent visualization and control. Limitations have been reported in bladders
MINIMALLY INVASIVE SURGERY (V BIRD AND M DESAI, SECTION EDITORS)
Robotic Surgery in Pediatric Urology Jason P. Van Batavia & Pasquale Casale
Published online: 23 March 2014 # Springer Science+Business Media New York 2014
Abstract Minimally invasive laparoscopic procedures for urological diseases in children have proven to be safe and effective, with outcomes comparable to open procedures. Technical advances, including improved instruments and high-definition cameras, have contributed to the expanded role of minimal invasive surgery (MIS) in children. The major drawback to laparoscopy has been the relatively steep learning curve due to the technical difficulties of suturing and the limitations of instrument dexterity and range of motion. Recently, robotic-assisted laparoscopic surgery (RAS) has gained popularity in both adult and pediatric urology. RAS has several advantages over conventional laparoscopic surgery, particularly in the improved exposure via magnified 3dimensional view and simplification of suturing with the increased degree of freedom and movement of the robotic arm. This review discusses the role of RAS in pediatric urology and provides technical aspects of RAS in specific urologic procedures as well. Keywords Robotics . Laparoscopy . Minimally invasive surgery . Pediatrics . Urology
Introduction With the recent advances in equipment and surgical techniques, minimally invasive surgery (MIS) has become an widely accepted and efficient technique in both adults and children. Laparoscopic surgery is associated with minimal morbidity when compared to standard open surgery, and has the advantages of a quicker postoperative recovery, increased magnification, superior cosmetic outcome, less postoperative This article is part of the Topical Collection on Minimally Invasive Surgery J. P. Van Batavia : P. Casale (*) Department of Urology, Columbia University Medical Center, Division of Pediatric Urology, Morgan Stanley Children’s Hospital/NY Presbyterian, New York, USA e-mail: [email protected]
pain, lower analgesic requirements, and shorter hospital stays [1–3]. The major drawback of the pure laparoscopic approach has been the relatively steep learning curve for the procedure given the technical difficulties of suturing and anastomosis. These limitations can be minimized through the use of robotic surgical technology [4–6]. Advantages of Robotic Surgery Since its inception as a military tool for remote surgical care of injured soldiers, and with its subsequent expansion into clinical practice in the late 1990s and 2000s, robotic-assisted surgery (RAS) has gained enormous popularity in adult urology [7]. The daVinci Surgical System (Intuitive Surgical, Sunnyvale, CA, USA) provides the advantages of a novel dual-channel telescope that enhances visualization by providing a highly magnified 3-dimensional (stereoscopic) image that improves hand-eye coordination. Furthermore, this magnified image can be combined with tremor filtration and motion scaling, which allows for delicate motions in small areas, thus enabling much wider adoption of a procedure that would otherwise require advanced laparoscopic expertise. Additionally, robotic technology assists the pediatric surgeon by increasing dexterity and precision of movement with a robotic wrist-like mechanism that allows for up to 90 degrees of articulation and 7 degrees of freedom [8]. The overall benefit over conventional laparoscopy is to reduce the learning curve for intracorporeal suturing and performance of MIS [12]. While robotic surgery was initially thought not feasible in children before adolescence due to the smaller working spaces and large size of the robot, RAS is now in use throughout pediatric urology. Uses in Pediatric Urology The most common procedure performed robotically in pediatric urology is pyeloplasty for ureteropelvic junction obstruction [5]. Utilization of RAS in pediatric urology has recently expanded to include virtually all surgeries performed by the
402, Page 2 of 7
pediatric urologist, particularly ureteral reimplantation as well as both total and partial nephrectomy [6, 9]. Even complex reconstructive urologic procedures have been amenable to the robotic approach, including appendicovesicostomy and bladder augmentation [10, 11]. Although long-term outcome analysis of robotic pediatric urology series has been largely unexplored, the same advantages of laparoscopic over open conventional surgical procedures apply: more rapid recovery, less postoperative pain, less analgesic use, and shorter hospital length of stay [13••].
Important Principles of RAS As with any surgical procedure, RAS requires a unique skill set that must be learned, practiced, and mastered by the pediatric urologist. This includes an understanding of both anatomy and physiology for planning of trocar placement as well as the ability to embrace the technology with its constantly evolving instruments and equipment. The pediatric patient represents a smaller working environment compared to the adult, which can lead to port site conflicts and instrument collisions. Children are also thought to be more sensitive to intra-abdominal pressure, have a higher likelihood of crepitance development, and have less resistant (compliant) abdominal walls. Sakka et al. noted that children 2–6 years of age had significant decreases in cardiac index when initial intra-abdominal pressures of 12 mmHg were used and that these changes reversed upon reducing the pressure to 6 mmHg [14]. Taking these differences into account, the senior author uses working pressures of 6–10 mmHg in infants (0–2 years) and 10–12 mmHg in older children and adolescents [14, 15]. Another important difference between children and adults is the greater incidence of aerophagia and gastric insufflation during anesthesia induction in children, which when combined with the more rapid gastric emptying time seen in children, can lead to rapid insufflation of the entire small bowel. Distended small bowel can present problems during trocar placement and can hinder visualization/access during RAS. To minimize these effects, the authors recommend immediate placement of orogastric or nasogastric tube immediately after endotracheal tube insertion to decompress the stomach. Additionally, the bladder in infants is in a more abdominal location, which increases the risk of bladder injury during trocar insertion. This risk can be minimized by placement of a urethral catheter prior to gaining access. The use of robotic surgery simulators, and what D. Anders Ericsson calls “deliberate practice,” can overcome the limitations of experience gained only in the operating room [16•]. Another critical principle of RAS is mentorship and training under an expert in the field. The mentor is able to both teach the proper skills and techniques as well as address bad habits, which can then be unlearned.
Curr Urol Rep (2014) 15:402
General Techniques Gaining Access The robot has both 8-mm and 5-mm diameter instruments, and the most commonly used camera scope is 12 mm in diameter. Typically, an open-access (Hasson) technique is used first to place the 12-mm camera port. This technique involves opening the skin, fascia, and muscle until the peritoneum is exposed. The peritoneal cavity is then entered and the trocar placed under direct vision. The use of this open technique has been shown to decrease the risk of major vascular injury in large multicenter analyses [17–19]. An alternate approach for the initial trocar placement is to use the Veress needle. The needle itself utilizes a spring-loaded “safety” insert that is designed to prevent iatrogenic visceral injury. The Veress needle is placed blindly into the abdominal cavity, and insufflation occurs through the needle. Proper placement is supported by placement of a saline-filled syringe on the needle. Aspiration should show gas in the syringe, and saline injected into the needle as the syringe is removed should quickly enter the abdomen (the so-called hanging saline drop test). When gas is insufflated via the Veress needle, one should see high flow rates at low pressure. If these findings are not observed, the needle should be withdrawn and placement reattempted before the trocar is inserted. We usually place the camera port in the superior aspect of the umbilicus, although depending on the age and size of the patient, this site may be placed more inferior if it affords better triangulation to the operative organ. The abdomen is insufflated with CO2 at the desired pressure, and the 12-mm, 0-degree telescope is inserted to view the area of insertion for iatrogenic trauma. In addition to the 12-mm camera, a 5-mm endoscope is available, although it is monocular and provides only 2D images. Next, the working trocars (often two separate 5-mm trocars, although 8-mm trocars are available) are inserted under direct vision. For upper urinary tract surgery, the robotic device is docked from the ipsilateral side; for lower urinary tract surgery and orchiopexy, it is docked from the foot of the bed. The robotic instruments are available in both 8-mm and 5–mm sizes, which is determined based on the size of the patient. A fourth arm is available for grasping and retraction. Generally, we utilize Maryland bipolar forceps as a grasper and either monopolar hook device or curved scissors during dissection. The instruments can be changed quickly and easily by the bedside assistant. After appropriate dissection and exposure, the dissecting instruments can be switched to robotic needle drivers (often in both arms) to make suturing easier. As the technology has evolved over time, results have improved and are now nearly identical to open procedures, utilizing 5-0, 6-0, and 7-0 sutures as in open surgeries.
Curr Urol Rep (2014) 15:402
Procedure Nephrectomy Indications for simple nephrectomy include poorly functioning or nonfunctioning kidney secondary to UPJ obstruction, obstructing stone, reflux nephropathy, single-system ectopic ureter, and multicystic dysplastic kidney [20]. Simple nephrectomy may also be utilized for donor nephrectomies, while radical nephrectomy may be performed for renal cell carcinoma and Wilms tumor [21]. Simple nephrectomy can be performed with either conventional laparoscopic or robotic-assisted approaches, but as outlined above, the use of RAS for nephrectomy has several advantages: high-definition three-dimensional images, increased dexterity and range of motion, and gentler learning curve [22]. While both conventional laparoscopic and roboticassisted laparoscopic nephrectomy can be performed using either the transperitoneal or retroperitoneal approach, the transperitoneal procedure is more widely utilized in robotics, especially in the infant population, given the size of the ports and the robotic arms. Ultimately, the choice depends upon the surgeon’s experience and the need for additional procedures such as ureterectomy and/or bladder access. Retroperitoneal Approach Retroperitoneal access is different from the transabdominal approach in both port placement and patient positioning. Ports are placed posteriorly or laterally, depending upon surgeon preference. Given the size of the robotic arms compared with the size of the patient, a posterior approach is more difficult in pediatrics for children 12 years and younger [19]. For access, the first trocar incision is made 15 mm long and 10 mm inferior from the lower border of the tip of the 12th rib. This trocar is fixed with a purse-string suture to make an airtight seal, and the working space is created by gas insufflation dissection. Alternatively, the working retroperitoneal space can be created by utilizing two index fingers of powder-free surgical gloves, which are placed one inside the other and attached to the end of the 5/10-mm trocar sheath. Next, 500 ml of warm saline is instilled through the insufflation channel of the trocar, and after completed dissection, the trocar is reinserted without the balloon. Pneumoretroperitoneum is established using a maximum pressure of 12 mmHg (or alternative pressure if age/weight appropriate) and a 5-mm or 10mm 0-degree telescope is inserted through this first trocar. The two working ports are then placed under direct vision, with the first trocar inserted posteriorly near the costovertebral angle and the second trocar inserted 10 mm above the top of the iliac crest in the anterior axillary line. Care must be taken to avoid transperitoneal insertion of the second working trocar by ensuring that the retroperitoneal working space is fully developed and identifying the deep
Page 3 of 7, 402
surface of the anterior wall muscles before inserting the trocar. Using this access technique, the kidney is approached posteriorly and Gerota’s fascia is incised parallel to the psoas muscle. Next, the perirenal fat is dissected to reveal the lower pole of the kidney, followed by identification of the renal pelvis, which is then mobilized. Ideally, the ureter is located first and can be transected to form a handle that can be used to guide the surgeon to the renal hilum. Transabdominal Approach The transabdominal approach can be performed in one of two ways: with the patient in the supine position with rotation of the table 45 degrees, or with the patient in a modified flank position (contralateral decubitus) with a 60-degree elevation of the flank. The ipsilateral arm can be placed on an elevated armrest in a straight extended or elbow-bent configuration or in a hand-in-pocket position at the patient’s ipsilateral side. First, the camera port is placed in the umbilicus (via either the Hasson or Veress technique), and then the working ports are placed under direct vision. The first working port is placed either midline at a point at least 4 cm above the umbilicus or lateral to the ipsilateral rectus muscle at the subcostal border. The second working port is placed either in the midline at least 4 cm below the umbilicus or in the midclavicular line at the level of the anterior superior iliac spine. In infants, the more cephalad working port should be placed subxiphoid in the midline, and the more caudal working port either as lateral as possible to the rectus muscle or suprapubically. When placing ports suprapubically, caution must be taken to avoid iatrogenic injury, especially to the bladder. The robot is docked over the ipsilateral shoulder, and the procedure is performed as described for laparoscopic approach [23]. Gargollo et al. have described an alternative approach to port placement, termed the HIdES technique, in which the robotic working port, camera port, and 5-mm assistant port are placed below the line of a Pfannenstiel incision. The second working port is then placed infraumbilically [24]. Heminephroureterectomy and Partial Nephrectomy Heminephroureterectomy (HNU) and partial nephrectomy may be indicated in children with duplication anomalies such as nonfunctioning upper pole kidney with ectopic ureter or ureterocele, cystic malformation of upper pole kidney, and nonfunctioning refluxing lower pole kidney [25]. The magnification and high-definition 3D imaging of the robot are particularly advantageous for these children since the upper and lower poles of the kidney are often divided by a clear vascular and anatomic plane that can be visualized. Roboticassisted HNU and partial nephrectomy can also be performed via transperitoneal or retroperitoneal approach in a similar manner to nephrectomy, with identical port placement and initial exposure of the ureters and hilum. The resection of
402, Page 4 of 7
the affected moiety can be accomplished either with the hook or scissors cautery, ultrasonic shears, or bipolar device. Prior to patient positioning, an open-ended ureteral catheter can be placed cystoscopically into the unaffected moiety in order to inject methylene blue after moiety transection to ensure that there is no leakage. For HNU, once the heminephrectomy is complete, the robot typically needs to be re-docked from the foot of the bed for access to the bladder. The senior author prefers the transperitoneal approach because, if bladder access is needed, one can readily turn the robotic instruments to the bladder for repair. Pyeloplasty Pyeloplasty is performed for ureteropelvic junction obstruction (UPJO), which is characterized by a functionally significant impairment of urinary transport. UPJO can be caused by intrinsic obstruction or smooth muscle impairment, anatomical abnormalities (e.g., high ureteral insertion) or extrinsic obstruction (e.g., anteriorly crossing vessel) at the precise junction of the renal pelvis and ureter. Robotic assisted laparoscopic pyeloplasty is performed in a similar manner to conventional laparoscopic pyeloplasty, but with the significant advantage of easier and more precise suturing with the robotic arms and instruments. As with robotic nephrectomy, robotic-assisted pyeloplasty can be performed using a transperitoneal or retroperitoneal approach with the same patient positioning and the same robotic docking as described above. Retroperitoneal Approach With the retroperitoneal approach, the surgeon approaches the kidney from the posterior side. From the posterior side, Gerota’s fascia is identified, and the fascia is incised in a parallel manner to the psoas muscle. Next, the perinephric fat is dissected to expose the lower pole of the kidney from which the renal pelvis can be identified and mobilized, allowing access to the UPJ. The UPJ is minimally dissected from surrounding connective tissue, and special attention must be paid to the anterior surface of the UPJ to identify or confirm the absence of any crossing vessel pathology. Transperitoneal Approach During the transperitoneal approach, the left UPJ is exposed transmesenterically and the right UPJ is exposed with minimal colonic mobilization. While the senior author prefers a transmesenteric approach for access to the left UPJ, alternatively, the colon on the left may be mobilized if the surgeon prefers. If the colon for a left UPJ is mobilized, the surgeon must continue the mobilization medially over the aorta [26]. The surgical procedures follow the same steps as the conventional laparoscopic approach [27]. If the renal pelvis is extremely dilated and/or difficult to access, a hitch stitch can be passed through the abdominal wall and placed through the renal pelvis. The bedside assistant
Curr Urol Rep (2014) 15:402
then places the stitch on traction by lifting both ends of the suture extracorporeally and placing a clamp on both ends just above the skin. This helps to elevate and stabilize the renal pelvis for easier access during incision of the UPJ and reanastomosis. The hitch stich is often helpful if a pyelolithotomy is necessary. After the UPJ is exposed, the pelvis is incised and the ureter is spatulated laterally. Depending upon the type of pyeloplasty to be performed, the renal pelvis, UPJ, and/or ureter can be incised to fit the repair. Reports in the literature have described various laparoscopic and robotic pyeloplasty techniques, including AndersonHynes dismembered pyeloplasty, “Y-V plasty,” and the “bypass pyeloplasty,” in which a side-to-side anastomosis is made between the dilated portion of the ureter just distal to the UPJO and the lower dependent portion of the hydronephrotic renal pelvis [28•, 29]. Choice of dismembered versus nondismembered pyeloplasty is dependent upon surgeon experience and the anatomy of the renal pelvis and ureter. In all pyeloplasties, the anastomosis is performed using a running suture. While a 6-0 monofilament absorbable suture is preferable for the anastomosis, any 5-0 or 6-0 absorbable suture can be used, depending upon the patient’s size. If a ureteral stent is required, a double-pigtail stent can be placed after the posterior wall of the anastomosis is closed. The stent can be placed through the anterior abdominal wall via a 16-gauge angiocatheter. A guide wire is first placed through the angiocatheter and manipulated by the robotic instruments down the ureter in an antegrade fashion. Next, the stent is passed over the guide wire. To confirm proper position of the stent into the bladder, the bladder can be filled with methylene blue so that one can observe the efflux of blue urine when the stent enters the bladder. Alternatively, the ureteral stent can be placed via cystoscopy in a retrograde fashion, with a dangling string to allow removal in the office. Postoperatively, the senior author leaves a urethral catheter overnight, and if a doublepigtail stent is placed, it is removed in 2 to 4 weeks. The results described in the literature show similar success rates for the robotic and open procedures, at around 95 % [13••, 30, 31]. Ureterocalicostomy Robotic ureterocalicostomy can be performed in children with UPJ obstruction and significant lower pole caliectasis or those with an exaggerated intrarenal pelvis. It may also be useful in patients who have failed previous pyeloplasty and have a minimal pelvis [32]. The procedure utilizes the transperitoneal approach, with similar trocar placement as described above for pyeloplasty. If necessary, after colon reflection, the ureter is transected and ligated using absorbable sutures at the level of the renal pelvis. Next, the most dependent lower pole calix is incised using hot scissors with minimal bleeding secondary to the thinned parenchyma of the lower pole system. The ureter is then spatulated and the posterior anastomosis of the ureter with the lower pole calix is performed using 5-0 absorbable suture in a running fashion.
Curr Urol Rep (2014) 15:402
After the posterior anastomosis is complete, the ureteral stent is placed as described above. The anterior anastomosis is performed in an interrupted fashion, which allows visualization and precise alignment of the calix with the ureteral mucosa without tension on the renal parenchyma. The stent is left in place for approximately 6 weeks and removed at the same time as retrograde ureteropyelogram to confirm an intact and healed anastomosis. Ureteroureterostomy Ureteroureterostomy is indicated in children with a duplicated collecting system in which the upper pole ectopic moiety has function. At the beginning of the procedure, all patients undergo cystoscopy with retrograde pyelogram and open-ended ureteral catheter placement into the lower pole. A urethral catheter is then placed and the external portion of the ureteral catheter is secured to the urethral catheter. Both catheters are prepped into the operative field, as access to the ureteral catheter is essential during the robotic portion of the procedure. The senior author utilizes the transperitoneal approach for robotic ureteroureterostomy, with trocar placement similar to that described above for pyeloplasty. The upper pole ectopic ureter is dissected free, transected, and spatulated. The proximal portion of the upper pole ureter is then anastomosed to the lower pole ureter in an end-to-side fashion. The anastomosis is performed with 6-0 absorbable suture in a running fashion. During this portion of the procedure, the open-ended ureteral catheter can be instilled with methylene blue to test the integrity of the anastomosis. The distal upper pole ureteral segment is then dissected and removed all the way to the level of the vagina in girls and the prostate in boys. As the transperitoneal approach affords easy access to the distal ureteral segment for resection, we recommend removing this segment in all children undergoing ureteroureterostomy. Ureteral Reimplantation Open ureteral reimplantation is the established procedure for primary vesicoureteral reflux (VUR). Over the past decade, successful laparoscopic and robotic-assisted laparoscopic ureteral reimplantation has been described via both extravesical and vesicoscopic approach [33–35, 36••]. Indications for reimplantation in children with VUR are controversial, but may include breakthrough urinary tract infection, worsening reflux, and unresolved high-grade reflux with evidence of upper tract scarring/damage. Transvesical Approach For the laparoscopic Cohen procedure using a pneumovesicum, the patient is placed in the supine position with legs apart. The bladder is filled with saline solution via a urethral catheter, and the 12-mm camera port is placed directly into the dome of the bladder through the
Page 5 of 7, 402
midline using an open technique or under direct visualization via a flexible pediatric cystoscope. Next, the bladder wall and skin are secured to the trocar using 3-0 absorbable suture secures. The working ports (8-mm or 5-mm) are inserted at the midclavicular line midway between the umbilicus and pubis, and all ports are secured to the abdominal wall. This stitch is utilized later to close the bladder. To insufflate the bladder, the urethral catheter is attached to suction to drain all saline from the bladder as CO2 is introduced via the port. The robot can then be docked over the patient’s feet. The reimplantation is performed in a manner similar to the open technique, with insertion of a 6-cm segment of a 5Fr feeding tube or 4Fr open-ended ureteral catheter into the ureter. The ureteral stent is secured with 4-0 absorbable suture prior to ureteral dissection. Next, hook or scissors cautery is used to dissect and mobilize the ureters. The submucosal tunnels are formed using the scissors starting from the original hiatus in a cross-trigonal manner to the contralateral side of the trigone [26]. After incision of the mucosa at the site of the new hiatus, the ureter is brought through the submucosal tunnel and ureteral anastomosis performed using 4-0 absorbable anchoring sutures to secure the ureter to the bladder musculature. 5-0 absorbable sutures are used to attach the ureter to the mucosal cuff, and the original hiatal mucosa is closed using a running 5-0 absorbable suture. Upon completion of the reanastomosis, the working ports are removed and the bladder holding stitches are tied down. The fascia at each port site is closed, and a flexible cystoscope is inserted transurethrally to thoroughly inspect the bladder. Finally, a urethral catheter is placed and kept in overnight. It should be noted that this technique is extremely challenging but provides excellent visualization and control. Limitations have been reported in bladders
