The robot-assisted ureteral reconstruction in adult: A narrative review on the surgical techniques and contemporary outcomes.

Study concept and design: Kulthe Ramesh Seetharam Bhat; Young Hwii Ko Data acquisition: Kulthe Ramesh Seetharam Bhat Data analysis: Marcio Covas Moschovas Drafting of the manuscript: Kulthe Ramesh Seetharam Bhat; Young Hwii Ko Critical revision of the manuscript: Vipul R. Patel.

Retroperitoneal fibrosis is a rare condition that causes extrinsic compression of the ureter because of extensive fibrosis of the retroperitoneum from either benign or malignant conditions, although two-thirds of the cases are idiopathic. Mufarrij and Stifelman [ 51 ] described the first case of robotic ureterolysis, where in the flank position, the colon is mobilized and the entire length of the ureter is exposed. Segments encased by the fibrous capsule are released by splitting the capsule until the adventitia of the ureter is visible. Finally, the ureter is intraperitonealized by wrapping the omentum around it. Since its initial description, multiple reports of cases have been published that demonstrate the feasibility and safety of robotic ureterolysis [ 52 , 53 ].

The authors declare no conflict of interest.

While robotic applications for ureteral surgery have been reported prominently in the field of pediatric urology, especially for relieving congenital obstruction in the ureteral pelvic junction, contemporary studies across the world have consistently reported its potential for malignant, iatrogenic, and traumatic conditions, which are predominant in adults. Several pioneering reports have indicated that a robotic approach for ureteral reconstruction is both safe and feasible. However, urologists should keep in mind that robotic assistance in ureteral surgeries has been primarily reported in studies involving highly skilled surgeons, and its oncological safety for malignant etiologies remains debatable. The lack of comparative study design and low-level evidence generated from the retrospective small series without long-term follow-up makes it difficult to identify the unique advantage of the robotic approach over conventional treatment. Thus, there is a need for qualified prospective trials for wider acceptance, as well as for resolving the uncertainty regarding the advantages of robotic approaches over the conventional ones. However, contemporary reports have demonstrated that the robotic approach can be used as an alternative option for ureteral construction, even in the absence of haptic feedback, which can be compensated using various surgical techniques and enhanced three-dimensional visualization.

Stem cells comprise the basic building blocks of tissue engineering, biomaterial scaffolding, and growth factor supplementation. Biomaterials used as scaffolds for inducing ureter regeneration include small intestinal submucosa, decellularized ureter, or synthetic grafts, such as Gore-Tex [ 54 ]. A lack of animal models that can mimic human ureters is an important limitation that has prevented the further development of tissue engineering techniques. In addition, it is difficult to develop ureteral substitutes with peristalsis. In line with this, a collagen-based tubular scaffold with radial elasticity was recently developed by Versteegden et al. [ 55 ], which, in combination with a regenerated smooth muscle layer, was found to be ideal for restoring a neo-ureter. Moreover, the use of arteries as ureteral substitutes has also been described, as they have an intrinsic extracellular matrix ultrastructure, with collagenic composition similar to that of the ureters [ 56 ]. Furthermore, venous grafts and porcine ureter grafts have also been used as scaffolds, and in some cases, may be lined with smooth muscle tissue and urothelium. In addition, Zhao et al. [ 57 ] proposed the use of extracellular matrix blood vessels with mesenchymal stem cells to bridge the ureteral graft.

The widespread use of robotic surgery has motivated urologists to apply robotics in typical surgical settings where open and laparoscopic approaches have long been the standard of care [ 1 ]. Ureteral reconstruction encompasses a wide spectrum of diseases with different etiologies, including iatrogenic, congenital, and malignant conditions, across the upper and lower ureter, each requiring unique approaches for surgical correction. Owing to their minimal invasiveness and high dexterity, robotic ureteral reconstruction procedures for the upper tract were initially applied in the field of pediatric urology. As such, there are limited data on the outcome of robotic surgery for the repair of the upper urinary tract in adults. In the case of lower ureteral disease, there has been increasing interest regarding robotic ureteral surgery as a kidney-sparing procedure for distally located upper tract urothelial carcinoma (UTUC), including distal ureterectomy and segmental ureterectomy [ 2 ]. Both procedures, concomitant with or without a psoas hitch or Boari flap, are recommended in recently available guidelines as reliable alternatives to replace the standard radical nephroureterectomy [ 3 ]. Nevertheless, the lack of comparative studies based on heterogeneous conditions makes it difficult to perform a meta-analysis and establish a solid conclusion on the unique benefit of the robotic approach over the open approach and conventional laparoscopy in the general population. Thus, by reviewing contemporary published articles, we sought to establish consistent findings regarding robotic ureteral reconstruction in adult patients. Given the retrospective, single-arm design of the majority of reported studies, we also aimed to investigate the feasibility and benefit of robotic surgery in different etiologies and provide a summary of the suggested surgical techniques. Despite recent technological advances, the absence of tactile feedback in currently available robotic surgical systems is a significant drawback that makes it difficult to identify an area of interest [ 4 ]. Therefore, conducting imaging studies before robotic ureteral procedures is a pivotal step in planning surgery. Because of the variety in the location and size of tumors in UTUC, each robotic ureteral procedure is performed in an individualized fashion. Computed tomography imaging is currently the gold standard technique for the identification and localization of the lesion. If the area of interest is narrow, pre-insertion of a ureteral catheter up to the area of interest before surgery could provide additional information. In a patient with a pre-existing percutaneous nephrostomy (PCN) tract, a ureteral access sheath can be inserted under general anesthesia, enabling the insertion of a flexible ureteroscope in an anterograde fashion. One of the unique benefits of robotic technology is the use of indocyanine green (ICG), which can be visualized under near-infrared fluorescence (NIRF) to identify lesions. A ureteral catheter and/or a PCN tract can be used to inject 10 mL of ICG into the diseased ureter, above and below the stricture point. Intraoperatively, NIRF is activated to assist in the identification of the ureter and localize the margins of ureteral strictures [ 5 ]. The position of the patient should be tailored according to the area of interest. In general, the patient position depends on the type of procedure and the location of the area of interest. For procedures on upper tract lesions, including the renal pelvis and upper ureter, lateral decubitus or modified decubitus position can be recommended. For procedures on lower counterparts, the patients usually placed in the dorsal lithotomy position and steep Trendelenburg position, and the robot is brought into position between the patient's legs, as with conventional prostatectomy. In cases that require additional ureteral or bladder procedures by cystoscopy or ureteroscopy, the lithotomy position may be used, albeit with great caution, owing to possible collisions of the instrument arm with the patient's leg or the bedside assistant. However, this conventional position limits access to the bladder, which is mandatory in many cases, especially for retrograde placement of a ureteral stent. Slater et al. [ 6 ] performed 14 distal ureteral reconstructions, including three Boari flap procedures using the da Vinci Si system, and suggested side-docking of the robotic patient cart. The da Vinci Xi series has an additional advantage that it provides a wider range of motion and minimizes external collisions between each robot arm [ 7 ]. Moreover, side-docking helps to provide adequate access to the perineum, and its interchangeable camera trocars help in placing the camera in any trocar, thus providing various angles and enhancing the visualization. The latest da Vinci SP system has been demonstrated to be safe and feasible in a small single surgeon series [ 8 , 9 ]. Trocar placement for robotic ureter reconstruction should be individualized depending on the area of interest, workload of the procedure, type of robotic system, and patient positioning.