Bioregenerative Umbilical Cord Amniotic Membrane Allograft Ureteral Wrap During Robot-Assisted Ureterolysis

Abstract

Omental wrap is commonly performed after ureterolysis to prevent ureteral obstruction from recurrence of periureteral adhesions and fibrosis. We present the case of a 37-year-old Caucasian woman with a history of two cesarean sections and laparotomy for the treatment of endometriosis. She subsequently developed right flank pain caused by a right distal ureteral stricture requiring a chronic indwelling ureteral stent. Diagnostic laparoscopy revealed extrinsic compression of the ureter for which robot-assisted ureterolysis was performed. Because of inadequate omentum, we report the initial use of a cryopreserved bioregenerative umbilical cord amniotic membrane allograft to perform a ureteral wrap to promote ureteral tissue healing and serve as an adhesion barrier to prevent recurrence of the fibrosis.

Clinical History

The patient is a 37-year-old woman who presented with chronic right flank pain that worsened for the past year. She was referred locally for urologic evaluation and was diagnosed with a long right distal ureteral stricture that was managed with a chronic indwelling internal ureteral stent that remained in place for 6 months. The patient has a long history of endometriosis and had previously undergone laparotomy and excision ∼15 years prior. She also has a history of two cesarean sections, with planned tubal ligation that was unable to be performed secondary to extensive right-sided pelvic adhesions. The patient was referred to our institution for further evaluation and definitive management of her right distal ureteral stricture.

Physical Examination and Diagnosis

The patient's body mass index 21.29 kg/m² and her physical examination was notable for a well-healed Pfannenstiel incision. Her renal function was normal with a creatinine of 0.82 mg/dL and estimated glomerular filtration rate of 95 mL/(min·1.73 m²). Urinalysis revealed large blood, consistent with presence of an indwelling ureteral stent, and urine culture was negative.

CT of abdomen and pelvis with contrast performed at the time of her initial presentation revealed right-sided hydroureteronephrosis to the level of the distal ureter, which was unable to be adequately observed because of surrounding soft tissue infiltration (Fig. 1A). Based on the patient's prior gynecologic surgical interventions, the etiology of her right distal ureteral stricture was deemed most either extrinsic compression from retroperitoneal pelvic fibrosis or recurrent endometriosis, or intrinsic from potential prior ureteral injury.

FIG. 1.

(A) Sagittal view of CT demonstrating soft tissue overlying distal right ureter, postureteral stent placement, distal to iliac vessels (arrow). (B) Intraoperative right retrograde pyelogram demonstrating distal right ureteral narrowing (arrow).

Office cystogram was performed in consideration for potential distal ureterectomy with ureteroneocystostomy and Boari flap reconstruction, showing a normal appearing bladder with a capacity of 350 mL. The patient's right indwelling ureteral stent was observed under fluoroscopy with no radiographic evidence of encrustation. Two weeks before planned surgical intervention, the patient's right indwelling ureteral stent was removed in the office to allow for ureteral rest and associated reduction of ureteral and periureteral inflammation at time of surgery.

Intervention

Surgery began with cystoscopy and right retrograde pyelography, demonstrating a 3 cm narrowing of the distal ureter with the most distal aspect of stricture ∼4 cm from the ureterovesical junction (Fig. 1B). A flexible ureteroscope was attempted to be passed through the ureteral stricture without success.

A four-arm robotic transperitoneal approach was employed. Extensive lysis of adhesions was performed and inspection revealed a scant amount of omental tissue. Adhesions arising from the intestines, appendix, and right ovary encased the right ureter (Fig. 2A), and appendectomy and right salpingo-oophorectomy was performed. Robot-assisted ureterolysis was then performed for extensive retroperitoneal fibrosis noted distal to the right common iliac vessels extending to the level of the bladder (Fig. 2B, C). After completion of the ureterolysis (Fig. 2D), ureteral patency was confirmed as the flexible ureteroscope was able to pass the area of the ureteral narrowing, with the absence of intraluminal ureteral obstruction. A 6F-24 cm indwelling internal ureteral stent was placed. Vascularity of the ureter was confirmed with intravenous administration of indocyanine green and use of near-infrared fluorescence imaging (FireFly™; Intuitive Surgical, Inc.) (Fig. 3). Omental wrap could not be performed because of the absence of adequate omental tissue likely secondary to her multiple pelvic surgeries and extensive lysis of adhesions. As a result, a 6 cm × 3 cm cryopreserved umbilical cord amniotic membrane allograft (CLARIX™; Amniox Medical, Inc.) was used to wrap of the distal ureter and was secured with 3-0 monofilament suture (Fig. 4).

FIG. 2.

(A) Appendix (blue arrow) and right ovary (white arrow) adherent to the underlying ureter at the level distal to crossing of the iliac vessels. (B) Exposed ureter (blue arrow) surrounded by fibrotic tissue after salpingo-oophorectomy and appendectomy. (C) Dissection of the posterior fibrotic rind off of the ureter (blue arrow) during ureterolysis. (D) Global view of pelvis demonstrating the freed ureter (isolated with vessel loop) postureterolysis.

FIG. 3.

(A) White light image of right distal ureter isolated with vessel loop. (B) Near-infrared fluorescence image of right distal ureter (FireFly™; Intuitive Surgical, Inc.) confirming vascularity of ureter after intravenous indocyanine green administration.

FIG. 4.

(A) Securing of bioregenerative umbilical cord amniotic membrane allograft (CLARIX™; Amniox Medical, Inc.) around distal ureter. (B) Completed umbilical cord amniotic membrane allograft ureteral wrap.

Operative time was 3 hours and 28 minutes and estimated blood loss was 50 mL. The Foley catheter was removed the next morning and the patient was discharged on the first postoperative day.

Follow-Up and Outcome

The patient underwent ureteral stent removal 4 weeks postoperatively. She has not had recurrence of flank pain or gross hematuria since stent removal. Renal ultrasonography at 6 weeks after stent removal showed resolution of right hydroureteronephrosis. Nuclear medicine renal scan was performed at both 6 weeks after stent removal and 6 months postoperatively. At 6 months the scan revealed left and right diuretic T ½ of 9 and 12 minutes, respectively. Both ultrasonography and renal scan demonstrated resolution of her right ureteral obstruction.

Discussion and Literature Review

Ureterolysis with omental wrap has been shown to be an effective solution for the management of retroperitoneal fibrosis, with open surgery demonstrating >90% stent-free rate at 12 months. The first laparoscopic ureterolysis procedure was described by Kavoussi in 1992, and since the popularization of robotic surgery, robot-assisted laparoscopic ureterolysis has also been shown to be safe and effective. Keehn et al. in 2011 reported on 18 patients who underwent robotic ureterolysis with omental wrap, 3 of whom had a bilateral procedure for a total of 21 renal units. Eighteen (85.7%) renal units had radiographic and symptomatic resolution of ureteral obstruction without reoperation.¹ Three of 21 renal units required repeat robotic ureterolysis with ureteral reimplantation, laser endoureterotomy, or robotic ureteroureterostomy, after which all patients had radiographic and symptomatic resolution of obstruction.

Omental wrap has been utilized classically in ureteral reconstruction as a technique to provide the ureter with a healthy tissue layer with good blood supply, and to protect the ureter from recurrent fibrosis. Although usually adequate in patients who have not undergone previous abdominal surgery, there may be cases, in which the amount of omentum is limited or unable to reach the level of the diseased ureter. We encountered this challenging situation in this case. There are other strategies to insulate the ureter from the fibrotic retroperitoneal tissues, including lateralizing the ureter or intraperitonealizing the ureter; however, both of these options were not feasible during out procedure because of the distal location of the stricture and the absence of enough laxity in the diseased ureteral segment.² As a result, a 6 cm × 3 cm bioregenerative umbilical cord amniotic membrane allograft was used to circumferentially wrap the freed ureteral segment as a substitute for omentum. Cryopreserved umbilical cord amniotic membrane matrix promotes healing through angiogenic, anti-inflammatory, and antifibrotic properties, thus reducing the likelihood of scaring while also serving as an adhesion barrier. This matrix has been utilized in other disciplines, including ophthalmology, orthopedics, and neurosurgery, as well in nerve-sparing robot-assisted radical prostatectomy, to accelerate return of continence and potency.³ Our intention for using the bioregenerative umbilical cord amniotic membrane allograft was to assist with ureteral healing, prevent recurrent stricture formation, and to provide a barrier from the surrounding fibrotic tissues.

To our knowledge this is the first report in the literature on the use of an umbilical cord amniotic membrane allograft during robot-assisted ureterolysis. A case report in the gynecologic realm detailed the use of 2 cm × 12 cm amniotic membrane allograft wrapped around an injured ureter at the time of robot-assisted excision of endometriosis.⁴ The ureteral injury was noted intraoperatively and involved a partially denuded 1 cm area of the distal left ureter. The patient eventually required cystoscopy, retrograde pyelography, and ureteral stent placement on postoperative day 7 for flank pain caused by ureteral extravasation in the area of a 1.5 cm stricture. After ureteral stent removal after 2 weeks, nuclear medicine renal scan and CT urogram at 3 and 4 months, respectively, showed no evidence of obstructive uropathy. Although in this case the amniotic membrane allograft was placed at the time of iatrogenic injury, the authors' intention for using the allograft was to promote primary healing of the ureter. This case report, as well as our experience, illustrates the utility of umbilical cord amniotic membrane allograft wrap, which can be used in the setting of ureterolysis, ureteral injury, or other ureteral reconstructive procedures.

Conclusion

We report the initial use of an umbilical cord amniotic membrane allograft ureteral wrap to promote healing and serve as a barrier to prevent recurrent adhesions. The bioregenerative nature of this matrix is ideal for patients with ureteral strictures undergoing ureterolysis in the absence of adequate omentum.

Abbreviation Used

CT

computed tomography

Disclosure Statement

N.C., N.V., and B.R.D. have no competing financial interests; R.M. is a lecturer in Boston Scientific, Inc. and TissueTech, Inc.

Funding Information

No funding was received for this article.

Cite this article as: Cheng N, Velazquez N, Desroches BR, Munver R (2020) Bioregenerative umbilical cord amniotic membrane allograft ureteral wrap during robot-assisted ureterolysis, Journal of Endourology Case Reports 6:4, 431–434, DOI: 10.1089/cren.2020.0185.