Robot-assisted laparoscopic urologic upper urinary tract reconstruction

Bowel preparation

As exposure can be further restricted by the presence of significant bowel gas or stool burden in the pediatric abdomen, some urologists have routinely prescribed polyethylene glycol or a suppository the day prior to surgery, along with instructions to maintain a clear liquid diet for 24 hours preoperatively. This practice is surgeon-dependent, but it can be considered for patients who have substantial constipation.

Preoperative urine cultures

There are no current guidelines on the utilization of preoperative urine cultures in robotic pyeloplasty, and as such, there are significant practice pattern differences. Given these variations, studies on the utility of these cultures are challenging to conduct, and meaningful conclusions are hard to draw. Preoperative cultures may be considered in patients with a history of urinary tract infections or with indwelling stents or nephrostomy tubes, as clearing preoperative bacteriuria may be prudent prior to urologic manipulation.

Retrograde pyelogram and stent placement

Retrograde pyelogram and stent placement may be performed in cases in which the anatomy is not well delineated on preoperative imaging and further clarification is needed. In infants in whom the extremely dilated pelvis displaces the UPJ, a retrograde pyelogram just prior to pyeloplasty allows the surgeon to identify the location of the UPJ and adjust port placement accordingly. In some cases, the pyelogram can also help assess the length of the narrowed segment, which may be longer than expected ( Fig. 61.1 ). In infants, retrograde stent placement may be ideal, as antegrade placement can be challenging with the risk of injuring the ureterovesical junction. Some surgeons may choose to place stents with a dangler extraction string such that it may be removed in the office without a separate anesthetic.

Patient positioning and preparation

If a retrograde pyelogram is performed prior to pyeloplasty, the patient is placed in the lithotomy position. Following a retrograde pyelogram and ureteral stent placement, a Foley catheter is placed for bladder decompression. An orogastric tube should also be placed to decompress the stomach. The patient is then positioned for the robotic portion of the case.

For the pyeloplasty, the patient is positioned in a modified flank position with the ipsilateral side elevated with a gel roll or rolled blanket. A padded bean bag may also be considered to help stabilize the patient. The ipsilateral arm is straight and in a neutral position. Some surgeons may prefer to have the contralateral arm bent at the elbow and supported by an arm board. However, keeping the contralateral arm straight has been described and offers easy access to the abdomen ( Fig. 61.2 ). A pillow or towel is placed between the legs, and the heels are well padded. In small children, flexion of the contralateral leg should be avoided as it may impede movement of the inferior robotic arm. The patient is secured to the table with towels and tape. The head should be supported on both sides with towels or gel foam to ensure that it remains in a neutral position during bed rotation. After securing the patient, the bed is rotated maximally both ways to ensure that the patient is adequately secured and does not move. A lower-body Bair Hugger may be considered to ensure the patient remains normothermic during the case.

The bed is then rotated toward the ipsilateral side so that the abdomen is flat for port placement. The abdomen is prepped and draped. It is important to prep as lateral as possible on the ipsilateral side to ensure that the ideal location of the hitch stitch is within the sterile field. In cases in which the stent is placed in an antegrade fashion, the external genitalia should also be prepped, and the Foley catheter should be placed on the field. A council tip catheter may be considered in girls. Following stent placement, a wire can be placed through the catheter to facilitate easier access to the urethra to confirm that the distal end of the stent is in the bladder via cystoscopy.

Port placement

Port placement varies slightly depending on the operative side, but they are essentially mirror images of each other ( Fig. 61.3 ). Port placement is also dependent on the patient’s age and the target anatomy. The camera port is placed at the umbilicus. Two working ports are used. One is placed in the midline about half-way between the xiphoid and umbilicus. The inferior working port can be placed about two-thirds the distance from the umbilicus and ipsilateral anterior superior iliac spine. In young infants, this port can be moved inferiorly and medially toward the midline to maximize working space. An additional working port may be placed above the superior working port or in the left upper quadrant for liver retraction for right-sided pyeloplasties.

Some may prefer the hidden incision endoscopic surgery (HIdES) approach, in which a majority of the ports are placed below the line of a Pfannenstiel incision. With this approach, the camera port is midline or in the contralateral lower quadrant and below the line of the Pfannenstiel incision. One working port is placed at the infraumbilical location, and another is placed in line with the camera port and approximately 1 to 2 fingerbreadths medial to the ipsilateral anterior superior iliac spine ( Fig. 61.4 ). This approach to port placement has comparable results and complication rates as the traditional approach to port placement.

Docking

Following port placement, the bed is rotated in the contralateral direction while the surgeon observes the UPJ with a laparoscopic camera. This allows the surgeon to determine the degree of rotation necessary to maximize exposure. The bed should be rotated enough for gravity to keep the small bowel out of the way. A laparoscopic Maryland or bowel grasper may be used to sweep the small bowel off the UPJ to help determine the optimal degree of rotation. For left-sided pyeloplasties for which a transmesenteric approach is feasible and desired, the bed should be rotated such that the small bowel falls out of the way, but the colon remains on top of the kidney and does not obstruct visualization of the UPJ. If this balance is not feasible, then the bed should be rotated enough such that the descending colon will drop after it is reflected.

In infants, the surgeon should also evaluate if the bladder is adequately decompressed by the Foley and whether there is significant rectal distention. If the bladder is not adequately decompressed, the circulator or bedside assistant, depending on whether the catheter is within the sterile field, may aspirate the catheter to ensure that the bladder is drained and does not reduce working space. A red rubber catheter may be placed in the rectum, if the rectum is filled with gas and affecting exposure. Once exposure is optimized, the robot may be docked.

The robot is typically on the ipsilateral side of the patient. The camera port, target anatomy, and robot base should be in a straight line. The bed may be angled to best facilitate this. The da Vinci Xi platform has a rotating boom, so the robot may be placed on either side of the patient and the boom rotated to the ipsilateral side. It is also equipped with a targeting capability that optimizes docking. Once the robotic arms are docked, one should ensure that there is at least one fist-length distance between the robotic elbows to ensure that there is adequate working space and the arms do not clash. The ports may also need to be pulled back under visualization, or “burped,” to maximize working space.

Ureteropelvic junction exposure

Once ready for the robotic pyeloplasty, attention is turned to exposing the UPJ. Dissection may be carried out with the use of a bipolar Maryland or DeBakey grasper in the left and a monopolar scissor or hook in the right for right-handed individuals ( Table 61.1 ).

A transperitoneal approach is standard, and the UPJ may be approached in a retrocolic fashion bilaterally or in a transmesenteric fashion on the left. With the retrocolic approach, the ascending or descending colon is reflected medially along the white line of Toldt, depending on the operative side. If dissection is challenging, it is important to not inadvertently take down the lateral attachments to the kidney, as this would cause the kidney to rotate medially and make exposing the UPJ more challenging.

Once the colon is reflected, the UPJ is located. If the pelvis is noted to be intrarenal or malrotated on ultrasound and the UPJ is not easily identifiable, one may first identify the ipsilateral ureter distally and follow it up toward the UPJ. Once the UPJ is identified, dissection is carefully conducted to expose the proximal ureter, the UPJ, and the medial pelvis.

When the exposure allows for a transmesenteric approach, the ureter can be identified just inferior to the pelvis and the mesentery opened based on that orientation. The ureter is then lifted, and dissection is carried up to the renal pelvis (RP) and UPJ. Care is taken not to injure any of the mesenteric vessels. Partial mobilization of the pelvis is undertaken prior to the placement of the hitch stitch, which facilitates further dissection.

Hitch placement

A hitch stitch is placed in the medial RP once exposure is adequate. A 3-0 polydioxanone (PDS) suture on a partially straightened SH needle is passed through the lateral abdominal wall inferior to the costal margin. The hitch is placed through the medial aspect of the RP and then passed back through the abdominal wall. During placement, care is taken to not angle the needle toward the major vessels. Once the hitch is placed, the needle is removed. Gentle traction is applied, and the stitch is snapped externally. This traction helps stabilize the pelvis and improves exposure for the anastomosis ( Fig. 61.5 ). It also helps with further dissection, if needed.

In cases in which the RP is rotated posteriorly, placement of a hitch in the identifiable pelvis may help rotate the RP into view and ease dissection until a more desirable exposure can be achieved. A second hitch may then be placed. Prior to pyelotomy, it is important to loosen the hitch to ensure that it is not distorting the orientation of the UPJ. The placement of the hitch stitch medially will then typically position the UPJ inferiorly and mark the true lateral position as most dependent.

Dismemberment, antegrade stent placement, anastomosis

Once the UPJ is adequately exposed, it is dismembered sharply from the superior-medial RP to the UPJ ( Fig. 61.6 ). The pelvis tissue may be used as a handle to allow manipulation of the ureter ( Fig. 61.7 ). Alternatively, a 5-0 Vicryl stitch may be placed sagittally on the medial ureter to provide a handle. The ureter is then spatulated laterally until the area of intrinsic obstruction is bypassed (see Fig. 61.7 ). Spatulation may be performed with curved scissors or Potts scissors. If using curved robotic scissors, care must be taken to ensure that the line of spatulation is straight to avoid spiraling.

The anastomosis may be performed using 5-0 or 6-0 Monocryl, PDS, Polysorb, or Vicryl sutures on noncutting needles, depending on surgeon preference. Needle drivers or black diamond micro forceps may be used for the anastomosis based on the surgeon’s preference. The first stitch is at the apex of the spatulation ( Fig. 61.8 ). The authors then perform a running anastomosis along the posterior wall. Once this is complete, the anterior wall anastomosis is started. If a stent has not been preplaced, it may be placed in an antegrade fashion after completing the posterior wall anastomosis and placing one or two stitches on the anterior wall. This will stabilize the apex. A wire with the preloaded stent is introduced into the abdomen through a 14-gauge (14G) angiocath. The wire and stent are passed down the ureter and into the bladder. Once the stent is placed, the wire is removed while the stent is stabilized with the robotic grasper. The proximal coil is then placed into the pelvis ( Fig. 61.9 ). The location of the distal coil may be confirmed by cystoscopy. Alternatively, the bladder may be filled with normal saline containing methylene blue dye or indocyanine green (ICG) and clamped. If the distal stent coil is in the bladder, reflux of the dyed fluid may be seen through the stent. ICG may be best visualized using the near-infrared fluorescence imaging available on certain robotic platforms. The anastomosis is then continued. Just prior to complete closure, the RP is irrigated to remove any blood clots that may occlude the stent. The anastomosis is then completed, and the tissue handle on the ureter is trimmed as necessary. At this point, the hitch is removed, and the port sites are closed. Jackson-Pratt (JP) drains may be considered in cases of challenging anastomoses or re-operative pyeloplasties but are otherwise not routinely used.

Foley Y-V plasty

In cases of high ureteral insertion without a crossing vessel or if there is significant UPJ scarring that precludes adequate mobilization of the RP, a Foley Y-V plasty may be considered. This method does not involve dismemberment of the UPJ. With this technique, a V flap is made in the medial, dependent aspect of the RP and extended along the lateral ureter, which forms the Y portion. The apex of the renal pelvic flap is then anastomosed to the most distal aspect of the ureterotomy. This method is not suitable in cases of crossing vessels, proximal ureteral strictures, or cases that require renal pelvic reduction.

Spiral flap

In cases in which the RP is large and there is a long, proximal ureteral stricture, a spiral flap may be used. An oblique incision is made on the lateral dependent RP between the UPJ insertion and renal parenchyma. The incision is carried medially with the medial line of the spiral extending through the UPJ and the proximal ureteral stricture. The apex of the flap is rotated and anastomosed to the end of the ureterotomy, and the UPJ is reconstructed over an indwelling stent.

Ureterocalicostomy

For some redo pyeloplasties or if the ureter and RP are very scarred, a ureterocalicostomy may be needed to facilitate a tension-free anastomosis. Leaving the UPJ intact, a lower pole nephrotomy is performed, and the proximal ureter is spatulated laterally. The ureter is then anastomosed to the lower pole calyx. Given the high risk of a urine leak, additional coverage of the anastomosis with omentum or perinephric fat may be considered. A nephrostomy tube may also be considered in addition to the indwelling stent to maximize drainage.

Vascular hitch

In select cases in which the UPJ obstruction is due solely to extrinsic compression rather than intrinsic ureteral narrowing, a vascular hitch approach has been described. In this technique, the crossing vessel is mobilized from the RP and secured in a more cephalad position by enveloping it in a fairly mobile anterior RP with interrupted sutures. ^, While this may be effective for a select group of patients, this approach would not address concomitant intrinsic UPJ obstructions, which are seen in as high as 24% of patients. As such, patient selection is critical for this approach.