Robotic kidney transplantation allows safe access for transplant renal biopsy and percutaneous procedures

Dear Editors, Robot-assisted kidney transplantation (RAKT) is being increasingly performed in selected centers with extensive experience in robotic surgery and kidney transplantation [1–3]. Several surgical techniques have been proposed for RAKT [2,4–6]. To date, most centers, including the European Association of Urology (EAU) Robotic Urology Section (ERUS)—RAKT group [1], follow the principles of the Vattikuti Urology Institute-Medanta technique, developed following the IDEAL framework for introducing surgical innovations [2,7], potentially with few technical nuances [8]. A key point of the Vattikuti-Medanta technique is the transperitoneal approach with final extraperitoneization of the graft after kidney reperfusion. In particular, the graft is allocated in an extraperitoneal pouch by reapproximating two peritoneal flaps prepared at the beginning of surgery (Fig. 1a–f and Video S1). This critical step aims to avoid graft torsion, facilitate postoperative graft monitoring, and allow convenient access for ultrasound-guided transplant renal biopsy and/or placement of nephrostomy tubes, if needed. Of note, despite commonly performed in routine clinical practice, there is lack of evidence on the use of ultrasound imaging for postoperative graft monitoring and on the feasibility and safety of percutaneous procedures after transperitoneal RAKT with extraperitoneization of the graft. As such, herein we report our experience after 31 RAKTs from living (n = 13) or deceased (n = 18) donors, performed by a single surgeon [G.V.] between January 2017 and July 2019 following the principles of the Vattikuti-Medanta technique [8]. (Video S1). Postoperative ultrasound imaging was performed according to a standardized protocol [9], without any technical difficulty related to the anatomic position of the graft (Fig. 1g). Notably, a laminar perirenal fluid collection was recorded in almost all patients at ultrasound examinations during the first postoperative period (i.e., postoperative day 1, 7 and at hospital discharge) (Fig. 1h). Subsequent follow-up evaluations showed a progressive reduction of the fluid collection until reabsorption within 20–30 days after surgery (Fig. 1i,j), con- firming the complete extraperitoneization of the graft. In our cohort, 5/31 (16%) patients underwent percutaneous transplant renal biopsy for suspected acute rejection (Fig. 1l,m). All biopsies were performed using an automated needle biopsy system, as recommended [10], and achieved proper diagnostic yield. Acute rejection was confirmed in one case. In addition, one patient required percutaneous placement of a nephrostomy tube (with antegrade insertion of a double-J stent) for hydronephrosis and rise in serum creatinine (n = 1, Fig. 1n). The anatomic extraperitoneal position of the graft achieved by RAKT (Fig. 1k) allowed safe performance of these percutaneous procedures since the early postoperative period, with no need for more invasive (i.e., laparoscopic) approaches and no periprocedural complications. We believe transperitoneal RAKT with extraperitoneization of the graft according to the Vattikuti-Medanta technique, which is likely to be increasingly performed by referral centers across Europe, allows to combine the advantages of minimally invasive surgery— from both patients’ and surgeons’ perspectives—with those of extraperitoneal open kidney transplantation, including the opportunity of a safe access for diagnostic and therapeutic percutaneous procedures during the postoperative period