Evolution of Robotic Technology in Urologic Surgery

Abstract

Over the last 25 years, the field of urology has seen the advent and evolution of minimally invasive surgical techniques. The robot in particular has been shown to be safe and efficacious in managing malignancies. More recently its application has been expanded to benign urological conditions. While some robotic applications have been well established, others remain at varying stages of evolution. Relative to open approaches, the robot has been shown to enhance intraoperative visualization and precision, mitigate surgeon tremor, hasten post-operative recovery, and shorten length of hospital stay for certain indications; however, it has also been associated with higher costs, longer operative times, and limited outcomes data. We review the evolution of robotic applications within urology and speculate on the future directions and implications within the field.

INTRODUCTION

Beginning with endoscopic procedures and later robotic technology, urologists have been among the first to pioneer minimally invasive surgical approaches. Such approaches are geared towards decreasing morbidity, hospital stay and post-operative discomfort while attempting to increase procedural precision and technical ease. Over the past 25 years, robotic platforms have been used to enhance surgical procedures, and their growing role continues to evolve.

Initial surgical applications of the robot date back to the 1980s, with demonstrated utility in stereotactic brain surgery [1]. One of the first urologic applications of the robot was a transurethral resection of the prostate using the Probot system, as reported by Davis et al. in 1989 [2]. Soon thereafter, the US Food and Drug Administration (FDA) approved the Automated Endoscopic System for the Optimal Positioning (AESOP) device (Computer Motion, Inc., Berkeley, CA, USA) [3], which, when used with EndoAssist, helps direct the robotic arm that holds the laparoscope by using voice, pedal, or infrared motion control, thereby replacing the surgical assistant during laparoscopic surgery [4]. In 1997, the da Vinci® Surgical System was used to perform the first robotic cholecystectomy [5]. At the time, it was the only telerobotic system available in the market, allowing the surgeon to operate remotely by controlling robotic arms performing surgical maneuvers during an operative case. By 2001, Intuitive Surgical, Inc. (Sunnyvale, CA) received FDA approval for prostatic surgery using this system. Since then, the role of robotic technology has expanded to include the management of several malignant and benign urological conditions.

Robotic-assisted surgery offers several advantages over conventional laparoscopy. These include 3D visualization, mitigation of surgeon tremor, magnification of the surgical field, and expanded range of motion, which can facilitate intracorporeal suturing when compared with conventional laparoscopy. Nonetheless, this technology has not yet been universally adopted due to its high cost, longer operative times, and limited outcomes data. Recently, Lee et al. reported on the process of establishing a robotics program, focusing on preparation of the hospital, operating room, and practice [6]. In the present review, we describe the current applications, outcomes, and drawbacks of robotic technology within urology and speculate on the future implications within the field. We focus on the more well-established applications of the robot, while deferring less established or experimental applications beyond the scope of the current review.

APPLICATIONS AND OUTCOMES

Prostate Cancer

Since the first robotically assisted laparoscopic radical prostatectomy (RALP) procedure described by Bender et al. in 2000 [7], the robot has played a monumental role in the treatment of localized prostate cancer. RALP is increasingly replacing the traditional open retropubic radical prostatectomy as the gold standard surgical approach. The number of RALP performed annually in the US increased significantly over the last decade, representing only 1% of all prostatectomies in 2001, to 40% in 2006–2007 [8], to currently an estimated 80% of prostatectomies in the US [9]. The most commonly utilized RALP technique is that developed by Menon et al. in 2003, the VattiKuti Institute Prostatectomy (VIP) [10]. A number of modifications to the VIP technique have since been developed, such as neurovascular preservation to improve potency rates [11,12].

RALP has been shown to be a safe and effective alternative to open techniques for the surgical treatment of localized prostate cancer. In a systematic review by Ficarra et al., both laparoscopic prostatectomy and RALP were found to demonstrate significantly lower blood loss, shorter hospital stay and lower complication rates when compared to the open approach [13]. However, they both involved longer operative times than the open prostatectomy. The rate of positive surgical margins was similar among all three techniques. The continence and potency rates were also comparable among the three modalities. Operator experience notably influences outcomes and complication rates [14]. Although no single study has yet proven superiority of RALP over the traditional open prostatectomy, longer follow-up data are still awaited.

Kidney Cancer

Another common application of robotic technology to urology is the robotic nephrectomy for kidney cancer. The partial nephrectomy has evolved as the standard of care for managing small renal lesions (<4cm), providing improved long-term results and preservation of renal function in comparison to radical nephrectomy [15]. The robotic-assisted partial nephrectomy was first reported in 2004 and has since gained acceptance as a viable alternative to the open approach for small renal masses [16]. Several reports have shown that robotic-assisted partial nephrectomy is safe, with acceptable pathological and functional outcomes [17, 18]. These results are very promising and show comparable outcomes to both open and laparoscopic approaches.

Bladder Cancer

The robot has been used to perform radical cystectomies in treating muscle-invasive bladder cancer, with the first series on robotic cystectomies published in 2003 by Menon et al. [19] and Beecken et al. [20]. Initially entailing an average of eight to nine hours per case in earlier series, these technically complex procedures have been reduced to an average operative time of four to six hours per case at experienced centers [21, 22]. Pruthi et al. published their experience with robotic cystectomies in 100 consecutive patients demonstrating low complication rates without compromising surgical outcomes (0% positive margin rates) [23]. Others have compared open radical cystectomies with robotic cystectomies in prospective studies on 187 patients [21, 24]. They report similar operative time between the two groups, but significantly lower blood loss, blood transfusion rates, and length of hospital stay in the robotic group. Robotic cystectomy for muscle invasive bladder cancer remains in its infancy, and the long-term outcomes are still awaited to justify its widespread use.

The use of robot has been extended to urinary diversion following cystectomy which can be performed either intra- or extracorporally. The intracorporeal approach is challenging technically and may take up to an average of nine to thirteen hours, limiting its widespread acceptance and confining the approach to high volume centers only [25]. Limited data with few case reports are available from large volume centers describing total intracorporeal ileal conduit diversion and bladder augmentation or reconstruction for benign indications [20, 26]. As for malignant indications, the main drawback cited in these reports is the relatively long operating time associated with these procedures. Most surgeons prefer extracorporeal bladder reconstruction or diversion when performed in conjunction with radical cystectomy to reduce the total operating time.

Benign Nephrectomy

The use of robotic technology now has been extended to a number of benign urological conditions as well. Laparoscopic removal of kidneys for benign indications has become widely accepted as the standard of care. Robotic manipulators such as AESOP were initially described to facilitate laparoscopic nephrectomies [27]. The first robotic-assisted laparoscopic nephrectomy was reported in 2001 [28]. Since then, multiple reports describing robotic-assisted nephrectomy have been published. While robotic technology maintains intraoperative dexterity, precision and ergonomics, no study has shown a clear advantage of the robot over the laparoscope for nephrectomies.

Ureteropelvic Junction Obstruction

Robotic pyeloplasties have been performed in both adult and pediatric populations for the treatment of ureteropelvic junction obstruction. A minimally invasive approach offers advantages over the traditional open approach, which entails a larger incision, longer hospital stay and higher morbidity. Studies have reported comparable success rates to open and standard laparoscopic approaches [29]. In a nonrandomized study, Gettman et al. reported shorter operative and anastomotic times with robotic-assisted pyeloplasty as compared to conventional laparoscopic pyeloplasty [30]. Bentas et al. reported an average operating time of 197 minutes in a cohort of 11 patients undergoing robotic pyeloplasty with 100% success rate at 12 months follow up [31]. With added experience operative times as short as 122 minutes have been described in larger series [32].

Ureteral Reconstruction

After successful application of the robot to pyeloplasties, novel applications of robotic technology were pioneered in other ureteral reconstructive surgeries including uretero-ureteral anastomosis and ureteral reimplantation. Robotic-assisted procedures have also been expanded to the pediatric population, though much of the surrounding literature remains in evolution. The challenges of pediatric robotic surgery include the limited working space in children and the size of the instruments of the robotic platform. Satisfactory outcomes have been described in small series of extravesical ureteral reimplantation using the da Vinci system [33].

Pelvic Organ Prolapse

The da Vinci system gained FDA approval for gynecological surgeries in 2005. Since then, robotic gynecological procedures, such as abdominal hysterectomy, have been performed for both benign and oncological indications. The most common urogynecologic procedure of interest to urologists is abdominal sacrocolpopexy for the treatment of apical or vaginal vault prolapse. The open approach has traditionally been considered the gold standard in managing apical vaginal prolapse, with excellent long term success rates reaching as high as even 100% [34]. This procedure, however, necessitates a large incision, lengthy recovery with long hospital stay, and increased morbidity and risk of complications as seen with any major open surgery. The introduction of robotic technology in treating apical or vaginal vault prolapse has minimized invasiveness and shortened recovery time and hospital length of stay when compared to open approaches [35]. Both approaches had equivalent reported short-term efficacy.

Benign Adrenal Conditions

After the advent of the laparoscopic adrenalectomy in 1992 [36], the robotic approach was first introduced by Horgan and Vanuno in 2001 [37]. Robotic adrenalectomies have been shown to be feasible, efficacious, and safe, and the robot provides enhanced visualization and magnification to allow more meticulous dissection. Short-term outcomes of robotic adrenalectomies are comparable to those of the laparoscopic approach, though operative times are longer in the former [38, 39]. Furthermore, given the expense of the robot, it remains yet to be elucidated whether robotic technology is superior from a cost-benefit perspective in comparison to the conventional laparoscopic approach for performing adrenalectomies.

Miscellaneous urological conditions

Robotic technology has been extended to other urological conditions for the purpose of vision, technical ease and frequently surgeon’s preference. These include vesico-vaginal fistula repair, colposuspension, and vaso-vasostomy. However, the literature is limited to case reports, and the robot has not yet gained widespread acceptance for these indications [40, 41].

CONCLUSION

Robotic technology has revolutionized urology over the last 25 years. Urological procedures are now increasingly performed utilizing robotic technology. In various urological centers the use of this technology has been extended to routine benign urological conditions. Literature supports the use of the robot for some of the benign and malignant indications. The robot carries the advantage of hastening recovery and shortening hospital stay in comparison to the open approach for several conditions; however, further cost-benefit analyses are needed at this time to justify the use of the robot in extended applications. While short-term surgical outcomes are promising and comparable to those of traditional open or laparoscopic procedures, long-term data is still lacking and necessary to prove superiority of robotic technology over conventional approaches.