Reconstructive management of the ureter is a challenging procedure and represents an evolving field in urology, especially in minimally invasive techniques. Treatment of ureteral defects, such as ureteral stricture, fistula, and urothelial cancer, requires ureteral reconstruction to obtain normal urinary drainage. The laparoscopic technique for creation of a Boari flap was initially described in 2001 by Fugita and colleagues. With the technologic developments in minimally invasive surgery, Schimpf and colleagues performed the first Boari flap procedure using a robotic platform. Robotic assistance offers the advantages of instrument flexibility during reconstruction and magnified vision. However, because of the limited number of cases and its technical novelty, clinical experience with laparoscopic and robotic Boari flap creation is still limited.
Indications and contraindications
The indications for a Boari flap in adults include iatrogenic ureteral injury, ureteral strictures, ureterovaginal fistula, and urothelial tumor located in the distal ureter. However, use of the Boari flap is contraindicated in cases of small-capacity irradiated bladder. The psoas hitch is an effective procedure to bridge a defect of the lower third of the ureter. Ureteral defects proximal to the pelvic brim usually require more than a simple psoas hitch. A psoas hitch can provide an additional 5 cm of length compared with ureteral reimplantation alone. Its advantages over a Boari flap include simplicity, improved vascularity, ease of endoscopic surveillance, and minimal voiding difficulties. Midureteral defects present a particular surgical challenge because this area has a tenuous blood supply and there are potential problems achieving a tension-free repair. When the diseased segment is too long or ureteral mobility is too limited for a primary ureteral reimplantation or psoas hitch, a laparoscopic or robotic Boari flap procedure may be a useful alternative. A Boari flap procedure can be performed to bridge defects up to 12 to 15 cm, and spiraled bladder flaps can reach to the renal pelvis in some patients. As with a psoas hitch, preoperative complete visualization of the ureter and evaluation of the bladder function are mandatory. Bladder outlet obstruction and neurogenic dysfunction must be addressed and resolved preoperatively for a sufficient amount of time. In the context of open surgery, complex reconstruction, as in flaps, normally requires a large incision as wide exposure is of utmost importance. The benefits of a laparoscopic or robotic approach for Boari flap surgery for patients with multiple medical comorbidities include less postoperative pain, reduced blood loss, and shorter hospital stay; however, with regard to technical feasibility, laparoscopic or robotic Boari flap surgery in patients with morbid obesity and major surgical history is challenging. Increased abdominal girth disturbs the range of motion of laparoscopic instruments and robotic arms. In addition, the surgeon must ensure that trocars and instruments are of the appropriate length to gain access to the target anatomy.
Although the psoas hitch and Boari flap have conventionally been performed by open surgery, the advantages of the laparoscopic or robotic technique have rapidly come into the limelight. With robotic assistance, instrument flexibility in a confined space and magnified vision are the additional advantages over laparoscopic reconstructive surgery.
Patient preoperative evaluation and preparation
Preoperative evaluation of patients who will undergo laparoscopic or robotic Boari flap surgery may depend on the reason for surgery. However, urine study and basic imaging are imperative.
Patients should be initially evaluated with urinalysis, urine culture and serum creatinine, and electrolytes. Basic imaging, including renal ultrasound and computed tomography urography with delayed images, will demonstrate ureteral defects or obstruction.
Technetium 99m mercaptoacetyltriglycine (MAG3) diuretic renography is of benefit in assessing the degree of preoperative obstruction and in postoperative follow-up for assessment of obstruction. Also, MAG3 renography confirms preoperative renal function. Concomitant antegrade and retrograde pyelography could provide exact information regarding the length and location of stricture (“up-and-down-o-gram”) with increased sensitivity and aid in preoperative planning. In patients in whom urothelial malignancy is suspected, ureteroscopic evaluation with washing cytology and biopsy is needed before surgery. In assessing for reconstruction of the ureter, a psoas hitch would be appropriate for defects of 6 to 10 cm; for longer defects—12 to 15 cm—a Boari flap procedure should be performed. After thorough review of all options, including psoas hitch and other endoscopic methods, if the laparoscopic or robotic Boari flap procedure is selected, evaluation of the bladder volume is needed. Review previous radiation or injury to the bladder, as well as previous pelvic surgeries, to plan the laparoscopic or robotic Boari flap procedure.
Patient preparation starts with informed consent. Inform the patient of possible postoperative complications such as obstruction, urine leakage, postoperative voiding symptoms, and the potential for open procedure conversion. Bowel preparation is usually not necessary; however, some centers perform bowel preparation using sodium phosphate or bisacodyl to decompress the colon during the transperitoneal approach. Obtain a urine culture and administer prophylactic antibiotics according to local sensitivity patterns and hospital protocol.
Operating room configuration and patient positioning
For patient positioning for the laparoscopic Boari flap procedure, the operating room is configured so that the entire team can view the procedure on the monitor. After the induction of general anesthesia and intubation, prepare the patient in a supine position and carefully secure the patient to the table for use of the Trendelenburg position with the operative site elevated at a 45-degree angle, which can be used to move the bowel contents away from the bladder. Surgically prepare the skin from the xiphoid process to the upper thigh, including the genitalia. An 18-French Foley catheter is inserted.
For patient positioning for robotic Boari flap surgery, prepare the patient in a lithotomy position and carefully secure the patient with a chest band to the table so that a steep Trendelenburg position can be used. The patient is positioned with the legs abducted 60 degrees and slightly flexed at the knee ( Figs. 26.1 and 26.2 ). Surgically prepare the skin from the xiphoid process to the upper thigh, including the genitalia; an 18-French Foley catheter is inserted after draping. The robot is docked between the patient’s legs.
For laparoscopic surgery, insert the initial trocar at the supraumbilicus using the Veress needle technique with insufflation with carbon dioxide (CO 2 ) to access the intraperitoneal cavity via a 12-mm supraumbilical port for the camera. Use CO 2 insufflation pressure up to 20 mm Hg to ensure tense pneumoperitoneum during port placement. Place the first 12-mm camera port on the supraumbilical site using a Visiport Plus optical trocar (Covidien, Minneapolis, MN), which permits visualization while the initial trocar is introduced. The camera port trocar is secured with a 1-0 silk suture to prevent inadvertent withdrawal during surgery. The abdomen is inspected with the 30-degree downward lens, and additional ports are placed under direct vision as follows. Place two additional 5-mm working trocars under direct vision at the level of the iliac crest along the lateral edge of the rectus muscle, triangulating these with the camera port. An additional 5-mm assistant port is placed on the cranial side on the line of the lateral edge of the rectus muscle ( Fig. 26.3 ).
For robotic Boari flap surgery, trocar placement through the introduction of the initial endoscopic (camera) port is similar to that for laparoscopic technique. After the initial endoscopic port has been introduced, the trocar positioning is as follows: two 8-mm robotic ports are placed bilaterally at each side 8 cm lateral to the midline camera port at the level of the umbilicus; a fourth 8-mm robotic port is placed on the ipsilateral side of the pathologic ureter 8 cm lateral to the ipsilateral 8-mm robotic port at a level 3 cm above iliac crest; a 5-mm assistant port is placed triangulating with the camera port and the 8-mm robotic port; a 12-mm assistant port is placed on the contralateral side of the fourth arm at a level 3 cm above the iliac crest; and 5-mm and 12-mm assistant ports are placed contralateral to the target side ( Fig. 26.4 ). The robotic arm is docked to the patient; bipolar Maryland forceps are placed on the nondominant hand, and monopolar scissors are placed on the dominant hand. The ProGrasp instrument (Intuitive Surgical, Sunnyvale, CA) is placed on the fourth robotic arm.
Operative procedure ( )
After placement of ports and completion of the docking procedure, laparoscopic or robotic Boari flap surgery requires the following steps:
Adhesiolysis of any intraabdominal adhesions.
Incision of the white line of Toldt and medial mobilization of the colon.
Ureteral identification and adequate mobilization while preserving ureteral vascularity.
Identification of the pathologic area of the ureter.
Mobilization of the bladder with preservation of blood supply. Dissection of the contralateral bladder pedicle if additional length is needed to ensure a tension-free repair.
Fixation of the bladder on the psoas muscle to avoid injury to adjacent neural structures.
Creation of the L-shaped bladder flap while preventing flap ischemia.
Ureteral spatulation and anastomosis with bladder flap.
Observation for hemostasis and drain placement.
Closure of the trocar sites.
The main principle of the Boari flap is to close the large gap with a tubularized L-shaped bladder flap; the bladder is mobilized to the pathologic area, with an anterior bladder flap of 2 cm and a base of 4 cm created and extended to the ipsilateral posterior dome. The ratio of bladder flap length to base width should be within 3:1 to prevent flap ischemia.
For long ureteral defects from 12 to 15 cm in length, a Boari flap technique should be performed in addition to a psoas hitch procedure.
Mobilizing the colon
The laparoscopic and robotic Boari flap technique is essentially a replication of the open Boari flap technique. The cecum or sigmoid colon is initially mobilized depending on the side of the pathology ( Fig. 26.5 ). Deflect the colon medially by incising the line of Toldt from the liver on the right side and spleen on the left side to the medial umbilical ligament. Then, extend the incision medial to the umbilical ligament on the anterior abdominal wall.
Identifying and securing the ureter
In female patients, make the initial dissection in the peritoneal fold between the bladder and uterus to gain access to the ureters in the region of the trigone. In male patients, the ureter can be seen as it crosses posterior to the vas deferens. Create a peritoneal window, and free and elevate the ureter inferior to the vas deferens.
After the mobilization of the sigmoid colon or the caecum, the ureter is identified. The ureter is dissected while preserving vascularity, and the fourth robotic arm is used for traction of the ureter caudally to the pathologic segment. Transect the normal ureter above the pathologic area and spatulate it posteriorly on the normal ureter proximal end ( Figs. 26.6–26.8 ).