Current status of robotic single-port surgery.

Robotic-assisted laparoscopic surgery in urology is an ever progressing field, and boundaries are constantly broken with the aid of new technology. Advancements in instrumentation have given birth to the era of robotic laparoendoscopic single-site technique (R-LESS). R-LESS however, has not gained widespread acceptance due to technical hurdles such as adequate triangulation, robotic arm clashing, decreased access for the bedside assistant, lack of wrist articulation, continued need for an axillary/accessory port, lack of robust retraction, and ergonomic discomfort. Many innovations have been explored to counter such limitations. We aim to give a brief overview of a history and development of R-LESS urologic surgery and outline the latest advancements in the realm of urologic R-LESS. By searching PubMed selectively for relevant articles, we concluded a literature review. We searched using the keywords: robotic laparoscopic single incision, robotic laparoendoscopic single-site, single incision robotic surgery, and R-LESS. We selected all relevant articles in that pertained to single-site robotic surgery in urology. We selected all relevant articles that pertained to single-site robotic surgery in urology in a table encompassed within this article. The development of the R-LESS procedures, instrumentations, and platforms has been an evolution in progress. Our results showed the history and evolution toward a purpose-built single-port robotic platform that addresses previous limitations to R-LESS. Even though previous studies have shown feasibility with R-LESS, the future of R-LESS depends on the availability of purpose-built robotic platforms. The larger concern is the demonstration of the definitive advantage of single-site over the conventional multiport surgery.

INTRODUCTION

There has been a great development in practice of urology with the progressive shift from laparoscopic to robotic surgery in past few decades. Single-site surgery is a great leap since the introduction to laparoscopic/robotic surgery. The first surgery using single-port as reported by Hirano et al. was retroperitoneoscopic adrenalectomy in 2005.[3] Robotic laparoendoscopic single-site (R-LESS) has undergone remarkable growth since inception, and it addresses numerous issues associated with its predecessor, LESS. There is a significant enhancement in optics and ergonomics. Reports also conclude improved cosmesis and reduced incidence of postoperative complications such as abdominal adhesions and incisional hernias with single-port surgery. At present, R-LESS is applied in various urological procedures, including nephrectomy (partial, simple, and radical), pyeloplasty, nephroureterectomy, prostatectomy, and sacrocolpopexy.

Even though R-LESS is still an evolutionary technique, efforts are made to address common complaints regarding difficulties of triangulation and instrument clashing.[2] Numerous efforts are made to overcome these hindrances by developing flexible endoscopes, curved trocars, semi-rigid robotic instruments, multichannel ports, and seven-degree wrist movement of the robotic instruments. The surgical approach has been reconfigured. The extraperitoneal and perineal approach has shown intelligent advantage because of the ability to maneuver the instrument arm about its axis without moving each individual arm. Our group has recently published preclinical study using such approaches.[4] The aim of this paper is to analyze the current status of R-LESS and to discuss its future.

MATERIALS AND METHODS

By searching PubMed selectively for relevant articles, we concluded a literature review. The keywords used in our search were robotic laparoscopic single incision, robotic laparoendoscopic single-site, single incision robotic surgery, and R-LESS. We identified 36 related articles in specifically in the field of urology. We selectively chose only those that pertained to single-site robotic surgery in urology.

RESULTS

We identified and reviewed 36 articles on R-LESS in the field of urology [Table 1]. Although there are substantially more in circulation describing R-LESS use in such procedures as cholecystectomy, colectomy, and hysterectomy we focused on those concentrating on urology. The very first report of R-LESS was in 2008 by Kaouk et al. of three patients describing three different urologic procedures using the da Vinci S robotic platform through a multichannel single-port.[5] These three first R-LESS procedures opened the gateway to advance this technique and was driven by the enthusiasm of decreasing the need for visible scars, decreasing postoperative pain during major abdominal surgery. It was also reported that using the robot did enhance surgeon experience, and eased the technicalities of the surgical procedures compared to pure LESS technique. However, this was not without limitations. The first generation da Vinci platform occupied substantial space extracorporeally which caused clashing of the arms and inhibited triangulation which was necessary for laparoscopic surgery. This lack of triangulation was described as “chopstick” that occurs due to the lack of wrist movement.[1]

Table 1

List of all relevant publications regarding robotic single-port surgery (study size and description is given where applicable)

The few studies that were published the following year in 2009 began to develop the R-LESS using the similar platform. The use of the GelPort was an effort to decrease the problems with the triangulation and arm clashing that was the ever present problem.[7] The access site for the robot did continue to be one of the primary issues with the robotic platform at that time. Won Lee et al. described using a glove size seven, and an Alexis wound retractor (Applied Medical, Rancho Santa Margarita, CA, USA) to facilitate further movement and flexibility of the robotic arms but was met with issues such as tearing the glove, loss of air pressure and increased operative time.[17]

Advancements also took place with regards to the robotic instruments. In 2010, our group first described the use of the VeSPA instruments and accessories in a preclinical study in pigs. These instruments were rigid as the standard da Vinci arms were, which allowed them to be flexed and crossed at the fascial level with the aid of curved cannulae. Furthermore, introduced in this study was a newly designed specific-purpose multichannel single-port. The software for the new instruments allowed the right robotic arm to be controlled by the surgeon's left hand and vice versa. This eliminated the issues with triangulation. However, these first generation instruments restricted surgeon's freedom and ability of wrist articulation. Soon after, the implementation of slightly shorter trocars and more flexible instruments were redesigned. These second-generation improvements enhanced the laparoscopic environment [Figure 1].

Figure 1

Top left: Photograph of new trocars in a single-site port. Bottom left: Photograph of single-port surgery with use of trocars. Right: Photograph of three trocars with adequate triangulation

The feasibility of R-LESS for partial nephrectomy in cases with larger tumor burden was first done by Tiu et al. in 2012.[21] In this retrospective study, patients were stratified into two groups depending on size either >4 m or ≤4 cm. The study reported safety of R-LESS in tumors >4 cm but with longer warm ischemia times (WITs) and length of stay in patients with higher mean nephrometry scores. It was only in 2013 that Komninos et al. published the Trifecta outcome study after partial nephrectomies (i.e., WIT <20 min, negative surgical margins, and no surgical complications) showing inferior outcomes for R-LESS compared to multiport surgery.[29] Even though total operation time and WIT are longer in R-LESS, the effect on renal eGFR return was only short-term. The ultimate return of renal function was influenced by the amount of renal mass preserved.[31]

A prospective study of 19 patients that underwent R-LESS in 2010 with published results in 2014 after 3-year follow-up.[35] This study was the first direct clinical application showing feasibility and safety in human population. The latest and perhaps the most dynamic innovation have yet to be released. Preclinical trials are currently undergoing and two studies have described the new purpose-built single-port robotic SP 1098 [Figures 2 and 3].[4] This system holds promise to overcome difficulties with previous techniques and instrumentation. This new platform permits three instruments, and an 8 mm camera, which all individually articulate, to utilize a single 25 mm port. The SP 1098 is designed to be compatible with the Xi side cart. As described by Ramirez et al. and Maurice et al. the excellence of this design allows instruments to be deployed through at 25 mm port intracorporeally while maintaining all seven degrees of freedom at the wrist.[438] These two preclinical studies show that this platform allows complex procedures to be feasible and eliminates several of the previous limitations.

Figure 2

Photograph of single-port specific robotic instruments

Figure 3

Illustration of single-port robotic instruments at work in a patient. The camera instrument works alongside of the assistant instruments during the surgery

DISCUSSION

The advantages of R-LESS are undisputable with shorter recovery times and less postoperative pain with better cosmetic outcomes. The major shortcomings with the initial laparoscopic single-port surgery were instrument clashing, difficulties with triangulation. This led to single-port surgery attempted with the multiport standard platform with the da Vini S and Si models with the introduction of Gelport. Unfortunately, the robotic arms still limited the triangulation angle which the VeSPA system and automatic instrument reversal techniques showed less external clashing problems but with the sacrifice of wrist movement. What was necessitated was a complete change in the entire robotic platform. This progression of technological need gave birth to the novel da Vinci SP 1098 platform. Specifically developed for single-site surgery is still in preclinical research phase.[438] The endowrist technology introduced in 2015 has been a step forward to avoid difficulties with triangulation especially/more so in surgeries with multiple sutures and knot tying.[37] Limitations of R-LESS as reported include a steep learning curve and the level of expertise required to perform these procedures. Moreover, the majority of the studies to date are retrospective analysis with very few prospective studies in small group of patients.

CONCLUSION

Although feasibility and better outcomes are reported with less invasive single-port, there still remains a concern for the demonstration of a clear advantage of single-port over the conventional robotic surgery. There are improvements in technology-mostly that robotic interface is being used now compared to laparoscopy, and that a purpose-built robot is now being developed. Hence with new technology, the authors believe the field of single-port surgery will move toward more efficient surgeries and more innovational operative techniques. Whether such techniques will impact outcomes and decrease morbidity has yet to be seen.

Financial support and sponsorship

Nil.

Conflicts of interest

Jihad H. Kaouk certifies that all conflicts of interest, including specific financial interests and relationships and affiliations relevant to the subject matter or materials discussed in the manuscript (e.g., employment/affiliation, grants or funding, consultancies, honoraria, stock ownership or options, expert testimony, royalties, or patents filed, received, or pending), are the following: Endocare, Inc., Intuitive. – J.H. Kaouk (consultant).