Robotic renal transplantation: Current status.

INTRODUCTION: Kidney transplantation (KT) has traditionally been performed by open renal transplantation, but recently, a few groups including our own have described a minimally invasive approach to KT. We aim to discuss the current status of robotic kidney transplantation (RKT) and describe our technique of RKT with regional hypothermia.
MATERIAL AND METHODS: We used the search terms "minimally invasive" OR "robotic" OR "robot assisted" AND "kidney transplantation." Papers written in English and concerning technical and/or clinical outcomes following minimally invasive kidney transplantation were selected. Three hundred and eighteen unique articles were retrieved and nine were relevant. Comparative outcomes data following RKT with regional hypothermia versus open KT (OKT) from our own group were also included.
FINDINGS: Nine papers, so far, have evaluated the role of robotic approach in KT and have conclusively established the feasibility, safety, and reproducibility of RKT, although these studies have been performed by experienced robotic surgeons/teams. The contemporary published series note that rejection rates were similar in RKT and OKT patients. Mean serum creatinine at 6 months in RKT and OKT patients was equivalent, across the three series. Most of the studies also note a dramatic reduction in the wound-related complication rates.
CONCLUSION: RKT appears to be a safe surgical alternative to the standard open approach of KT. RKT is associated with reduced postoperative pain, analgesic requirement, and better cosmesis. RKT, although in its infancy, appears to be associated with lower complication rates.

INTRODUCTION

End-stage renal disease (ESRD), as the name suggests, represents the terminal stage in chronic kidney disease and is defined by a glomerular filtration rate (GFR) of less than 15 mL/min/1.73 m2.[1] ESRD is associated with high morbidity and mortality.[1] Chronic kidney disease and ESRD globally result in approximately 735,000 deaths annually.[2] The prevalence of ESRD varies in the developed versus the developing world; the situation being much graver in the developing nations. True estimates are seldom available in the developing nations, such as India, due to lack/prematurity of nationwide kidney disease registries.[3] Conservative estimates, however, state that the annual incidence of ESRD in India is approximately 229 persons per million with more than 100,000 new patients entering the renal replacement programs annually.[4]

Different modalities exist for renal replacement therapy, such as hemodialysis, peritoneal dialysis, etc. however, kidney transplantation (KT) remains the treatment of choice for ESRD as it leads to longer survival and superior quality of life.[5]

KT has traditionally been performed by open surgery, but recently, a few groups including our own have described a minimally invasive approach to KT. A pure laparoscopic approach has been described by Rosales et al.[6] and Modi et al.,[789] whereas more recently, a laparoscopic approach with robotic-assistance has been described by Giulianotti et al.[1011] Boggi et al.,[12] our group,[13141516] and Tsai et al.[17] There is a strong rationale for utilizing minimally invasive surgery (MIS) in the ESRD patients. MIS (with robotic-assistance) leads to smaller incision, lesser surgical infections, technical complications, blood loss and postoperative pain, shorter hospital stay and convalescence period, and better cosmesis.[1819] These outcomes are important in the general surgical population but attain even greater significance in the fragile ESRD patients, where preventing these adverse perioperative outcomes not only leads to better convalescence in the short-term but also leads to improved graft and patient survival in the long term.[202122] Accordingly, in this review, we aim to discuss the current status of robotic kidney transplantation (RKT) and describe our technique of RKT with regional hypothermia.

EVIDENCE SYNTHESIS

A literature search of Medline (PubMed) and EMBASE was performed on 21st September, 2014 to retrieve all published articles on robotic KT (between January 1990 and June 2014). We used the search terms “minimally invasive” OR “robotic” OR “robot assisted,” AND “kidney transplantation.” Papers written in English and concerning technical and/or clinical outcomes following minimally invasive kidney transplantation (MIKT) were selected. Three hundred and eighteen unique articles were retrieved and nine were relevant [Figure 1]. Reference lists of the selected papers were scrutinized for additional relevant articles but yielded no additional studies. Comparative outcomes data following RKT with regional hypothermia versus open KT (OKT) from our own group were also included (manuscript under review and published as an abstract).

Figure 1

Flowchart representing the literature search results and inclusion of relevant studies

Table 1 summarizes the studies looking at outcomes following RKT in patients with end-ESRD. All studies, except one,[23] represent contemporary experience and were published between 2010 and 2014. Four studies were case reports and/or technical papers,[10121323] three studies reported detailed outcomes following RKT,[111517] and the remaining two studies dealt with the subject of patient safety and surgeon learning curve monitoring during adoption of a new technique, in the setting of RKT.[1416] All contemporary RKT studies were from four groups/teams (see legend in Table 1].

Table 1

Summary of the series looking at robotic kidney transplantation outcomes in patients with end-stage renal disease

SURGICAL TECHNIQUE

We have previously described our surgical technique of RKT with regional hypothermia in detail in a step-by-step manner (with diagrammatic illustrations and a surgical video),[15] and have also compared it with other approaches of RKT in a tabulated fashion.[24] Here, we recapitulate the major steps of the procedure briefly.

VIDEO: http://www.europeanurology.com/surgery-in-motion-video/1127/robotic-kidney-transplantation-with-regional-hypothermia-a-step-by-step-description-of-the-vattikuti-urology-institute-medanta-technique-ideal-phase-2a

After induction of general anesthesia, the patient is placed in supine position and ports are placed as described before (in a manner similar to robotic radical prostatectomy). After the ports and the GelPOINT (hand-assist device) are placed, the patient is moved to Trendelenburg position. The operation starts with identification and skeletonization of the external-iliac vessels followed by bladder dropdown. Once optimal lengths of external-iliac vein and external-iliac artery are exposed and minor tributaries controlled, the bladder is filled with normal saline and is prepared from ureteroneocystostomy. Next, the pelvic bed is cooled with ice-slush and the graft kidney is introduced (both introduced via the GelPOINT). Following graft introduction, the graft renal vein and artery are anastomosed to the external-iliac vessels in an end-to-side continuous manner utilizing Gore-Tex suture. After completion of vascular anastomosis, the graft kidney is extraperitonealized using a peritoneal flap. After this, ureteroneocystostomy is performed robotically using the modified Lich-Gregoir technique. The patient is closed in a standard manner and an on-table ultrasound i obtained routinely to check for graft vascular flow.

RESULTS AND DISCUSSION

Nine studies [Table 1], so far, have evaluated the role of robotic approach in KT and have conclusively established the feasibility, safety, and reproducibility of RKT, although these studies have been performed by surgeons/teams facile with robotic technology.

Hoznek et al.[23] were the first to utilize robotic assistance during performance of a KT operation; in the single patient reported by Hoznek et al. the access to iliac fossa was established via open surgery and robotic assistance was only utilized to perform the dissection and the anastomoses. The first case report of a “truly” robotic KT operation, hence, came from Giulianotti et al.[10] from Chicago in 2009 (7 years after the study by Hoznek et al). The operation took 223 min to be completed with a warm ischemia time of 50 min. Boggi et al.[12] soon thereafter reported the first RKT case from Europe. Both these studies, although robotic, did employ hand assistance during at least one phase of the RKT operation. Boggi et al. performed ureterovesical anastomosis by open surgery via the Pfannenstiel incision, made earlier to introduce the kidney, whereas Giulianotti et al utilized hand assistance to manipulate the graft intracorporeally. On the other hand, the RKT technique described by Menon et al.[15] was completely hand-assistance free. Furthermore, their technique also utilized intracorporeal graft cooling to maintain optimal graft temperature during vascular anastomoses, which the other studies did not utilize. Lastly, while all these three approaches have been transabdominal (though the final position of the graft is extraperitoneal in the approaches described by Giulianotti et al and Menon et al), the recent study of 10 patients reported by Tsai et al. represents the initial experience in robot-assisted retroperitoneal KT.

Out of the nine studies, only three studies have reported detailed outcomes after RKT. Table 2 summarizes the perioperative outcomes from these studies. The study of RKT by Oberholzer et al.[11] and Tsai et al.[17] were both performed under warm ischemia. The mean warm ischemia times were 48 min and 67 min, respectively. On the other hand, the RKT study by Menon et al.[15] consistently employed the use of regional hypothermia (using ice-slush) during performance of vascular anastomosis. We routinely achieved graft surface temperatures of 18-20°C and our mean re-warming time (with ice-slush) was 47 min and warm ischemia time was 2.4 min. Accordingly, Oberholzer et al. noted a slower return of the graft function in patients undergoing RKT which we did not observe possibly due to the renoprotective effect of hypothermia[25] (Figure 2B; unpublished data). We and Modi et al. (in their study of laparoscopic KT) both noted a significant reduction in analgesic requirements in patients undergoing MIKT (other RKT studies did not evaluate this endpoint). On average, OKT patients required 3.2 mg of the analgesic medication (morphine equivalent), whereas laparoscopic KT patients required 1.4 mg in the study by Modi et al. (P = 0.005). In our study, patients undergoing RKT used on average lesser analgesic (unpublished data; 21.1 mg PCA-morphine vs. 29.5 mg; P = 0.003) while also reported lower pain scores (Figure 2A; P < 0.05). This might be related, at least in part, to the significant reduction is size of the incision. Modi et al. reported an average incision size of 5.5 cm in patients undergoing laparoscopic KT compared with an average incision size of 17.8 cm in OKT patients (P < 0.001). Similarly, in our study, RKT patients had an average incision length of 6.1 cm versus 15.6 cm in OKT patients (unpublished data; P < 0.001) and Tsai et al. reported an incision size of 7.7 cm in their cohort of retroperitoneal RKT patients. In none of the studies there arose the need to convert the RKT to an open setting.

Table 2

Summary of perioperative outcomes in the series looking at robotic kidney transplantation outcomes in patients with end-stage renal diseasea

Figure 2

Trends (a) postoperative pain; (b) postoperative creatinine fall

Table 3 summarizes the functional outcomes and complication rates in patients undergoing RKT and OKT from the three series. Mean serum creatinine at 6 months in RKT and OKT patients was equivalent across the three series (Tsai et al did not report on outcomes in OKT patients and our data is presented in Figure 2B [unpublished data]). One patient undergoing RKT had delayed graft function (DGF) both in the studies by Oberholzer et al. (n=1; 3.6%) and Tsai et al. (n=1; 10%), whereas none of the patients in our cohort had DGF. In all three studies, there were no vascular complications (eg, vascular stenosis, vascular leak, or torsion).

Table 3

Summary of functional outcomes in the series looking at robotic kidney transplantation outcomes in patients with end-stage renal diseasea

Rejection rates were similar in RKT and OKT patients as reported by Oberholzer et al. [Table 3]. Oberholzer et al. also reported a dramatic reduction in wound complications in patients undergoing RKT (3.6% vs. 28.6%; P = 0.02). We also noted 0% wound complications in our RKT cohort; there is substantial evidence to support that reduction in wound complications, especially, wound infections leads to improved graft and patient survival in the long term.[21] Furthermore, from a societal point of view, Oberholzer et al. pointed out an important issue that by decreasing complication rates (such as wound complications and DVT/embolism), RKT might lead to attenuation of disparities that currently exist with regard to transplant wait times and access to transplantation in morbidly obese patients, solely due to the fear of having higher postoperative complications in these patients.[26] There was no graft loss in patients undergoing RKT in all three studies evaluating RKT. One patient died of acute congestive heart failure (1.5 months post-KT), in our study, due to pre-existing cardiac pathology.

In conclusion, RKT appears to be a safe surgical alternative to the standard open approach of KT. RKT is associated with reduced postoperative pain, analgesic requirement, and better cosmesis. RKT, although in its infancy, appears to be associated with lower complication rates when compared with both OKTs, and has graft function outcomes that are equivalent to OKT.