Buccal Mucosa Graft for Ureteral Strictures




Complex proximal ureteral strictures can be challenging to manage. Whereas distal ureteral to midureteral strictures can be successfully managed with ureteral reimplantation with psoas hitch or Boari flap, proximal ureteral strictures are often managed with ureteroureterostomy. However, when the affected ureteral segment is long, adequate mobilization to bridge the gap between healthy distal and proximal ureteral mucosa to allow for ureteroureterostomy may not be possible. Long or multifocal proximal ureteral strictures may require ileal substitution or autotransplantation of the kidney, options that are associated significant potential morbidity from bowel and vascular complications.


The use of buccal mucosa grafts (BMGs) as an alternative to ileal ureter or autotransplantation has been reported in several case series but has not gained widespread use, perhaps because of the need for an open approach and the relative unfamiliarity of urologists with BMG harvest. However, for reconstructive urologists, BMGs have been a mainstay of treatment for urethral strictures since the 1990s owing to particular characteristics that make it ideal for the urinary tract. It has a panlaminar vascular plexus ideal for engraftment and a thick nonkeratinized epithelium compatible with a wet environment. It is a graft material that has proven to be durable in the urinary tract without the risk of metabolic complications associated with use of bowel interposition. The application of robotic technology with its magnification, three-dimensional visualization, and articulated instruments to facilitate delicate suturing now allows buccal ureteroplasty to be performed in a minimally invasive fashion, which may result in more widespread adoption of this technique.


Indications and Contraindications


Buccal ureteroplasty should be considered in patients who have long or multifocal proximal ureteral strictures that are not amenable to ureteroureterostomy and are being considered for autotransplantation or ileal ureter. Ureteral injury may have various causes such as trauma, iatrogenic injury from ureteroscopy or failed prior reconstructive surgery, or long-standing nephrolithiasis. Renal scan should be performed to demonstrate obstruction and to assess adequate function in the affected kidney. Contraindications to buccal ureteroplasty include any oral diseases that prevent harvest of oral mucosa.




Patient Preoperative Evaluation and Preparation


Diuretic renography should be considered to determine degree of obstruction and differential renal function. If there is minimal function remaining in the affected kidney, then nephrectomy may be a better option.


The length of the defect in the affected ureter must be evaluated. An antegrade or retrograde radiographic evaluation may be performed depending on whether the patient has a nephrostomy tube. If the degree of stenosis does not allow flow of contrast past the stricture on evaluation, simultaneous antegrade radiography and retrograde radiography or ureteroscopy may be necessary to evaluate stricture length ( Fig. 30-1 ). If the patient has a ureteral stent in place, we prefer to remove the stent, and place a nephrostomy tube to allow for accurate evaluation of the affected ureter.




Figure 30-1


Demonstration of stricture length. The tip of the flexible ureteroscope is seen at the distal extent of the stricture (arrow), and antegrade nephrostogram via the nephrostomy tube demonstrates the proximal extent of the stricture. A wire is seen traversing the stricture.


Evaluation for BMG harvest includes careful review of any history of oral diseases such as leukoplakia, which may preclude harvest of oral mucosa.




Operating Room Configuration and Patient Positioning


Careful consideration must be given to operating room configuration owing to the varied components of the procedure, including the robotic-assisted laparoscopic approach, the ureteroscopic evaluation, and the BMG harvest ( Fig. 30-2 ). Patient positioning must allow adequate access to the patient’s mouth for buccal graft harvest as well as optimal configuration for the use of the robot. Practical considerations include positioning of the screens for the cystoscopic tower as well as the video tower for the robot.




Figure 30-2


Operating room configuration and patient positioning. Patient is positioned in modified right lateral decubitus lithotomy position for left-sided repair. The mouth is draped separately from the abdominal field for buccal mucosa graft harvest.


The anesthesia machine is at the head of the bed. The patient is positioned in a modified lateral decubitus position with the side of the affected ureter up. If the patient is female, a modified lateral decubitus lithotomy position with the legs secured in Allen stirrups is used to allow for access to the bladder ( Fig. 30-3 ). The upper arm is padded and secured to the patient’s side. All pressure points are padded. The genitalia are prepared into the field to allow for intraoperative ureteroscopic evaluation. The endotracheal tube is secured on the dependent side of the mouth to allow for buccal mucosa harvest from the contralateral cheek. The mouth is prepared and draped separately from the rest of the surgical field.




Figure 30-3


If the patient is female, a modified lateral decubitus lithotomy position, with legs secured in Allen stirrups, is used to allow access to the bladder.


The bedside assistant stands contralateral to the affected ureter and the robot is docked at a right angle to the patient’s back. The screen for the robot is placed cephalad to the robot, and the cystoscope tower is placed caudad to the robot to allow both the bedside assistant and the surgeon performing the ureteroscopy to see their respective screens. The scrub nurse stands by the bedside assistant to allow the passage of instruments. A stand with the cystoscopic equipment is at the foot of the bed, and a stand with the equipment for the BMG harvest is placed at the head of the bed.




Trocar Placement


The initial incision for the camera port is made cephalad to the umbilicus at the lateral border of the rectus ( Fig. 30-4 ). Three robotic ports are placed—one at the costal margin, another infraumbilical at the lateral border of the rectus, and the last between the umbilicus and anterior superior iliac spine—to allow for adequate spacing of all ports. An assistant port is placed between the camera port and the inferior robotic port. Ports are placed 8 to 10 cm apart as allowed by the patient’s size. An additional 5-mm trocar may be necessary for retraction of the liver for a right-sided dissection.


Sep 11, 2018 | Posted by in ABDOMINAL MEDICINE | Comments Off on Buccal Mucosa Graft for Ureteral Strictures
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