Since their initial introduction, robotic surgical systems have been adopted enthusiastically by the urological community. As practitioners and trainees grow accustomed to their ubiquity, these platforms serve as engines of surgical innovation, and the breadth of their applications will only continue to grow. Recent developments in robotic assisted reconstruction herald a transformation in the management of lower and upper urinary tract pathologies previously felt to be difficult or insurmountable, particularly in a reoperative or irradiated field. Robotic techniques not only augment conventional approaches with advanced instrumentation but also adapt and remix preexisting knowledge from other disciplines in order to achieve luminal patency and preserve function.

Posterior Urethra and Bladder Neck

While an endoscopic approach is reasonable for the initial management of bladder neck contracture (BNC) or vesicourethral anastomotic stricture (VUAS), addressing recurrent or refractory stenoses can be challenging. In addition to the technical difficulty of visualization and suturing in the narrow confines of the deep pelvis, open surgery may risk injury to the urinary sphincter complex, cavernous nerves or rectum. Ancillary maneuvers including pubectomy and combined abdominoperineal dissection may be necessary. In cases when open reconstruction does deliver success with respect to patency, a significant proportion of patients suffer de novo urinary incontinence and are at risk for subsequent erosion of artificial urinary sphincter (AUS) cuff, especially where there is a history of pelvic radiation. ¹ The cumulative morbidity of historical approaches may dissuade providers and patients from pursuing definitive treatment.

Several robotic assisted approaches to stenoses of the posterior urethra and bladder neck have now been described, all of which leverage the advantages of improved visualization, dexterity, and adjuncts such as near-infrared fluorescence (NIRF) imaging to facilitate precise anastomosis of well-vascularized tissues. ² Where the stenosis is nonobliterative, an anterior-only dissection with scar incision and interposition either with bladder flap advancement (see figure, a) or dorsal onlay of buccal mucosal graft (BMG) is suitable, obviating the need for posterior dissection and mitigating the risk of rectal injury. For complete obliteration, where complete mobilization and excision of diseased tissue is paramount, concurrent flexible cystoscopy and/or transrectal ultrasonography render posterior dissection significantly safer. The short-term and mid-term patency and continence outcomes of these techniques are highly encouraging. ³ Critically, if patients do require an AUS in the future, avoiding an upfront perineal dissection may improve long-term durability.

Upper Urinary Tract

Figure. Robotic assisted approaches to nonobliterative VUAS via anterior cystotomy with cystoscope light and wire visible and laparoscopic guided needle used in hydrodissection ( a), nontransecting distal ureteral reimplant with side-to-side anastomosis ( b), identification of the proximal ureter with intraluminal ICG (c) and augmented anastomotic appendiceal onlay ureteroplasty for right proximal ureteral stricture ( d).

Building on the concept of nontransecting urethroplasty, in which spongiosal periurethral vascularity is preserved, Slawin et al recently reported a multi-institutional experience with robotic assisted side-to-side ureteral anastomosis for patients with benign distal ureteral strictures. ⁴ A posterolateral cystotomy is anastomosed to a longitudinal anterior ureterotomy made proximal to the stricture (see figure, b). While conventional ureteroneocystostomy can be a reliable modality for short stenoses, circumferential mobilization and transection of the distal ureter is required, possibly affecting vascularity and resulting in recurrent stricture. The putative advantages of a nontransecting approach in addition to preserving the posterior ureteral blood supply include avoiding a potentially dangerous dissection over the iliac vessels if there is significant periureteral fibrosis as well as preserving the native ureteral orifice if future endoscopic intervention is needed.

The development of the more novel robotic approaches to mid and proximal ureteral strictures similarly proceeded from recognition of the difficulty of safe ureteral dissection in a multi-operated or irradiated field, the challenge of achieving tension-free anastomoses and the morbidity or technique expertise required for options such as ileal ureteral interposition or renal autotransplantation. In such cases NIRF can be used intraoperatively in conjunction with intraluminal indocyanine green (ICG) instilled either via a nephrostomy tube or ureteral catheter to identify the ureter and aid in its dissection (see figure, c). Alternately, white light from a flexible ureteroscope can also be used for this purpose. While ureteroureterostomy remains the gold standard for treatment of relatively short unifocal strictures, longer and more complex disease warrants consideration of robotic assisted ureteroplasty. First described in 2015, updated intermediate-term outcomes are now available for robotic ureteral reconstruction with BMG, demonstrating preserved success at 28 months in 87% of patients with low perioperative morbidity. ⁵ Obliterative and nonobliterative strictures (median length 3 cm) can be addressed with the technique. Where the ureteral lumen is patent, a longitudinal anterior ureterotomy preserves the posterior ureteral plate and allows for an onlay repair. For complete obliteration, diseased tissue is excised, a new posterior plate is created with the proximal and distal healthy ends of ureter and BMG covers the defect in an augmented anastomotic fashion. In either case, omentum or perinephric fat can be used to support the repair.

While BMG-based techniques have shown promising results, a potential concern is donor site morbidity, particularly where long defects may need to be bridged. Addressing these concerns, Jun et al have presented the largest series to date of robotic appendiceal ureteroplasty for right-sided strictures, where median length was 6.5 cm and 92% of cases demonstrated success at 15 months followup. ⁶ Intraoperatively, after determination of stricture length the appendix was mobilized and the patency of its lumen was confirmed. Intravenous ICG can be used to confirm vascularity of the appendiceal flap. Obliterative strictures or ureteral avulsions were treated with appendiceal interposition. Nonobstructive disease was addressed with ventral onlay after detubularizing the appendix (see figure, d). The length of ureter that can be augmented or replaced depends on the appendiceal lumen and its mesentery. Importantly, a third of the patients in this series had previous pelvic radiation. A long Boari flap, while possibly adequate to treat the stricture length reported here, may have resulted in markedly reduced bladder capacity.

Conclusion

While open surgical techniques will always play a role in the management of complex stricture disease, advances in robotics have shifted the paradigm toward offering definitive treatment to patients with challenging pathology. Future exposition of long-term outcomes, cost analysis and the feasibility of disseminating these novel approaches will ultimately determine their place in the reconstructive armamentarium.