Robotic surgery is increasingly implemented as a minimally invasive approach to a variety of gynaecological procedures. The use of conventional laparoscopy by a broad range of surgeons, especially in complex procedures, is hampered by several drawbacks. Robotic surgery was created with the aim of overcoming some of the limitations. Although robotic surgery has many advantages, it is also associated with clear disadvantages. At present, the proof of superiority over access by laparotomy or laparoscopy through large randomised- controlled trials is still lacking. Until results of such trials are present, a firm conclusion about the usefulness of robotic surgery cannot be drawn. Robotic surgery is promising, making the advantages of minimally invasive surgery potentially available to a large number of surgeons and patients in the future.
Definition and history of robots in medicine
The term ‘robot’ was first used in 1921 in a play by the Czech playwright Karel Čapek, entitled Rossom’s Universal Robots . The word ‘robot’ is derived from the Czech word ‘robota’, which means ‘forced labour’ or ‘serf’. One of today’s definitions of the term robot is ‘a device that automatically performs complicated often repetitive tasks’. Thus, only the earlier inventions, such as PUMA 560, PROBOT, and ROBODOC ® are robots true to the official meaning, as they carry out tasks automatically without human intervention. The devices used in gynaecological surgery today, such as the da Vinci ® (Intuitive Surgical, Inc., Sunnyvale, California) need the guidance of the surgeon to perform their tasks. Hence, surgery with these devices would be better defined as computer-assisted surgery, but the term robotic surgery has become the more common term.
The idea of creating a mechanical machine that can move or perform tasks on its own date back to the 10th century BC where a mechanical engineer in ancient China built a machine that looked and moved like a human. Major progress in the field of robotic technology, however, was not possible until the industrial revolution in the late 18th century, and the rapid advancements in electronics and computer technology of the last decades. Although robots in medicine are a relatively new field, a large number of different robotic and computer-assisted devices have been developed and are still under development. Only a few inventions, however, are repeatedly cited, including Arthrobot (1983, limb fixation in arthroscopic procedures ), PUMA 560 (1985, robotic arm used in a stereotactic brain procedure ), Probot (late eighties, automatic prostate resection ) and ROBODOC (1992, hip arthroplasty ). The basis for today’s robots used in laparoscopy was the concept of performing remote surgical procedures in a hostile environment, such as a battlefield. Consequently, early projects, such as the development of AESOP ® (Computer Motion, Inc., Goleta, CA), were partly financed by the Defence Advanced Research Projects Agency. After commercialisation of the technology, it was soon applied to civilian operating rooms. The camera holding system AESOP ® (Automated Endoscopic System for Optimal Positioning, latest version AESOP ® 3000, 1998) replaces the camera assistant during laparoscopy, as it can be controlled by the surgeon’s voice. Computer Motion, Inc. launched a few more robotic systems before it was bought by Intuitive Surgical, Inc. in 2003. The most popular of these systems is ZEUS ® ( Fig. 1 ). It consists of a surgeon control consol and three table-mounted robotic arms. One of the arms is the above mentioned camera holding system AESOP ® , and the other two are instrument arms. Both types of instruments, rigid and articulated instruments (MicroWrist ® Instruments) can be used. The surgeon sits ergonomically in front of a monitor from where he controls the instruments. With ZEUS ® , the world’s first transcontinental procedure, a laparoscopic cholecystectomy, was carried out in 2001, where the surgeon operated on a patient in Strasbourg while he was located in New York. As a result of the acquisition by Intuitive Surgical, Inc., ZEUS and other products of Computer Motion, Inc. (e.g. AESOP, HERMES, SOCRATES) were no longer produced and marketed. Therefore, discussions about today’s surgical robots mostly refer to the da Vinci ® Surgical System. Additionally, nearly all studies of the last years dealing with robotic surgery investigated the da Vinci ® system; hence, this review concentrates on issues related to this robotic system.
The da Vinci ® Surgical System
Intuitive Surgical, Inc. was founded in 1995. After securing licenses on the technologies developed by several institutions and merging ideas and inventions into a commercially available medical device, the first version of the da Vinci ® Surgical System was launched in 1999. In July 2000, the device received US Food and Drug Administration approval for laparoscopic surgery. The da Vinci ® system consists of three core components: a surgeons console, a patients-side cart and a high-definition, three-dimensional vision system. During operation, the surgeon sits at the console. The patients-side cart has four arms containing one arm for the camera and three arms for the interchangeable instruments. The change of the instruments during a procedure is realised by an assistant ( Fig. 2 ). The surgeon is able to control the instruments through movement of his fingertips ( Fig. 3 ). The specially designed instruments called EndoWrist ® Instruments have ‘90-degree articulation’ and ‘seven degrees of freedom’. The last important component of the da Vinci ® System is the three-dimensional vision system, allowing depth perception of the operation field. At present, three different versions of the da Vinci ® exist: da Vinci ® Surgical System (Standard) (1999), da Vinci ® S High-Definition Surgical System (2006) and da Vinci ® Si Surgical System (2009). The first version originally had only three robotic arms; in 2003 an updated version with four arms became available. The da Vinci ® Surgical System (Standard) is no longer marketed. The da Vinci ® S provides high-definition vision and a better range of motion of the robotic arms, as well as extended length instruments allowing multiple quadrant operations. The instruments are available in 5 mm or 8 mm width. The latest version, the da Vinci ® Si, has a second console; therefore, the possibility of simultaneous training of a second surgeon or for collaborative conduction of procedures exists. Intuitive Surgical Inc., states that, among other improvements, the device set up should be realised quicker with the da Vinci ® Si Surgical System. As the da Vinci ® Si has been launched as recently as 2009, most studies and cited critical points refer to former versions. Thus, some problems existing with the former version may be solved in the latest version. Whether the latest version could overcome, some disadvantages of its predecessors has to be clarified in comparative studies. The da Vinci ® Surgical System is currently used in many different specialties, including general surgery, head and neck surgery, cardiothoracic surgery and urology. In 2005, the US Food and Drug Administration approved the da Vinci system ® Surgical System for gynaecologic surgery. The number of installed da Vinci ® Surgical Systems and robotic procedures has steadily increased over the past few years. On 30 June 2012, 2341 da Vinci ® systems were installed worldwide; 1707 in the USA, 389 in Europe, and 245 throughout the rest of the world. One explanation for the growing interest in robotic surgery might be the expectation that, with robotic surgery, even complex procedures can be minimally invasive and carried out by a broader base of surgeons. Some limitations of conventional laparoscopy could, therefore be overcome and open procedures could be replaced by robotic surgery.
The da Vinci ® Surgical System
Intuitive Surgical, Inc. was founded in 1995. After securing licenses on the technologies developed by several institutions and merging ideas and inventions into a commercially available medical device, the first version of the da Vinci ® Surgical System was launched in 1999. In July 2000, the device received US Food and Drug Administration approval for laparoscopic surgery. The da Vinci ® system consists of three core components: a surgeons console, a patients-side cart and a high-definition, three-dimensional vision system. During operation, the surgeon sits at the console. The patients-side cart has four arms containing one arm for the camera and three arms for the interchangeable instruments. The change of the instruments during a procedure is realised by an assistant ( Fig. 2 ). The surgeon is able to control the instruments through movement of his fingertips ( Fig. 3 ). The specially designed instruments called EndoWrist ® Instruments have ‘90-degree articulation’ and ‘seven degrees of freedom’. The last important component of the da Vinci ® System is the three-dimensional vision system, allowing depth perception of the operation field. At present, three different versions of the da Vinci ® exist: da Vinci ® Surgical System (Standard) (1999), da Vinci ® S High-Definition Surgical System (2006) and da Vinci ® Si Surgical System (2009). The first version originally had only three robotic arms; in 2003 an updated version with four arms became available. The da Vinci ® Surgical System (Standard) is no longer marketed. The da Vinci ® S provides high-definition vision and a better range of motion of the robotic arms, as well as extended length instruments allowing multiple quadrant operations. The instruments are available in 5 mm or 8 mm width. The latest version, the da Vinci ® Si, has a second console; therefore, the possibility of simultaneous training of a second surgeon or for collaborative conduction of procedures exists. Intuitive Surgical Inc., states that, among other improvements, the device set up should be realised quicker with the da Vinci ® Si Surgical System. As the da Vinci ® Si has been launched as recently as 2009, most studies and cited critical points refer to former versions. Thus, some problems existing with the former version may be solved in the latest version. Whether the latest version could overcome, some disadvantages of its predecessors has to be clarified in comparative studies. The da Vinci ® Surgical System is currently used in many different specialties, including general surgery, head and neck surgery, cardiothoracic surgery and urology. In 2005, the US Food and Drug Administration approved the da Vinci system ® Surgical System for gynaecologic surgery. The number of installed da Vinci ® Surgical Systems and robotic procedures has steadily increased over the past few years. On 30 June 2012, 2341 da Vinci ® systems were installed worldwide; 1707 in the USA, 389 in Europe, and 245 throughout the rest of the world. One explanation for the growing interest in robotic surgery might be the expectation that, with robotic surgery, even complex procedures can be minimally invasive and carried out by a broader base of surgeons. Some limitations of conventional laparoscopy could, therefore be overcome and open procedures could be replaced by robotic surgery.
Conventional laparoscopy
Minimally invasive surgery has many well-known advantages, including reduced blood loss, less pain, fewer infections, reduced hospital stay, and faster return to normal life. Conventional laparoscopy, however, is associated with disadvantages for the surgeon, thus hampering the widespread use of this minimally invasive approach. Learning laparoscopic skills and being confident in advanced laparoscopic actions, such as suturing, is a challenging and often time-consuming task. Additionally, not all surgeons are equally skilled in acquiring the needed proficiency and in conducting laparoscopic surgeries. The conversion of the two-dimensional picture seen on the monitor into precise movements of the instruments is often difficult, as depth perception is minimised through the loss of three-dimensional vision. The restricted degrees of freedom of the instruments, the counterintuitive movements needed to guide the instruments to the area of interest, and the loss of the natural hand-eye co-ordination, can make laparoscopic procedures an exhausting and frustrating task, especially at the beginning of the learning curve. Owing to the transmission and amplification of the physiological tremor through the length of the rigid instruments, precise and filigreed actions can be complicated. The loss of haptic feedback further complicates laparoscopic procedures. Overall, these limitations influence the surgeon’s dexterity compared with the confidence and personal skill known from open procedures, potentially leading to frustration, especially in difficult operative situations. Consequently, many surgeons still feel uncomfortable with laparoscopic surgery. As laparoscopy is the gold standard in diagnosis and treatment of many diseases today, simple laparoscopic procedures can generally be conducted by most surgeons. Especially advanced laparoscopic procedures, however, such as myomectomies, are still a challenge for most surgeons and are often conducted only by experienced laparoscopists. Hence, in daily practice, many procedures that could be conducted laparoscopically by a surgeon with advanced laparoscopic skills are still conducted through laparotomy. Robotic surgery can eliminate some of the disadvantages associated with laparoscopy, but also creates new ones specific for this approach.
Advantages of the da Vinci ® Surgical System
The da Vinci ® Surgical System has several special functions aimed at overcoming the limitations of conventional laparoscopy and to mimic characteristic features known from open surgery. The three-dimensional, high-definition imaging allows stereotactic vision of the operation field, making depth perception possible. Additionally, the area of interest can be magnified up to 10 times. The surgeon’s hand movements can be scaled (5:1, 3:1, or 1:1) so that large movements of the surgeon’s hand are translated into smaller movements inside the patient. Furthermore, the system reduces the physiological tremor, which enables precise surgical manoeuvres, such as vascular anastomosis. As movements of the fingertips are directly transferred into movements of the instrument tips, the illusion emerges that the instrument tips are a continuation of the fingertips. Hence, natural hand-eye coordination leads to intuitive movements and handling of the instruments. Thus, together with the seven degrees of freedom provided by the instruments, surgeon’s dexterity is improved and may be comparable to the dexterity achieved in open procedures. The ergonomical sitting position during the operation increases the surgeon’s comfort, resulting in reduced fatigue owing to absence of unnatural, thus exhausting movements or positions often observed in conventional laparoscopy. As movements in robotic surgeries are intuitive, the learning curve is not as steep as in conventional laparoscopy. Therefore, even laparoscopically inexperienced surgeons might be able to acquire skills to conduct robotic surgeries within a relatively short time compared with the time required for being confident in respective laparoscopic tasks ( Table 1 ).
| Advantages | Disadvantages |
|---|---|
| Three-dimensional high-definition imaging allowing stereotactic vision. | Extensive preparation before robotic surgery can be implemented in a facility. |
| Depth perception. | High costs. |
| Scaling of hand movements. | Considerable floor space needed. |
| Reduction of physiological tremor. | Bulky instruments. |
| Natural hand-eye coordination. | Aesthetical disadvantage through different trocar placement. |
| Intuitive movements and handling of the instruments. | Lack of direct access to the patient. |
| Seven degrees of freedom of the instruments. | Delayed conversion to open procedure in case of emergencies. |
| Ergonomical sitting position. | Loss of tactile and force feedback. |
| Reduced surgeon fatigue. | Unproven efficiency. |
| Less steep learning curve. |
Disadvantages of the da Vinci ® Surgical System
Despite the numerous advantages of the da Vinci ® Surgical system, it certainly has substantial drawbacks that hinder the widespread implementation of its usage. Although the learning curve for robotic surgery is less steep than for laparoscopy, extensive training is also needed before surgeons can operate on patients. Additionally, the theatre team also need training to become familiar with the device set up as well as with the solution of potential problems during procedures. Hence, the preparation for implementation of robotic surgery in a hospital is a time- and resource-consuming process. As robotic surgery depends on technical innovations, it is likely that ever new upgrades may be available within short time frames. Although the continuous process of improving existing techniques is important and desirable, one problem might be that the technique of today is rapidly outdated and new upgrades may add additional costs to the already high costs of robotic surgery. The high costs associated with robotic surgery are definitely one of the main drawbacks (see section on costs). Another disadvantage is the considerable floor space is needed, as the instruments are bulky, which could be a problem if the available space is already limited. As a result, cost-intensive renovations might be conducted before robotic surgery can be implemented. Placement of the trocars in robotic surgery can differ from that in conventional laparoscopy, as the trocars must be placed in order to prevent the bulky robotic arms from interfering with each other. In robotic surgery, the trocars are often placed in an arch, which might be an aesthetical disadvantage for the patients compared with the more hidden scars after laparoscopy. The lack of direct access to the patient, but especially the restricted usability of the uterine manipulator, as well as the difficulty of removing the uterus or other specimens from the vagina, is stated as a significant disadvantage of robotic surgery in gynaecology. Furthermore, in case of emergencies, the time needed to convert to an open procedure may be delayed, as the instruments cannot be removed as quickly as in conventional laparoscopy. A further disadvantage is the loss of tactile and force feedback. In laparoscopy, the tactile feedback is reduced; however, it is completely absent in robotic surgery, potentially leading to inadvertent lacerations or frequent ruptures of suture material during knot tying. This problem may be solved after extensive training and may be partly compensated by the three-dimensional vision system. Additionally, new technological inventions may allow tactile feedback in the future. Finally, another main disadvantage is the unproven efficacy of robotic surgery compared with laparoscopy or laparotomy. To decide if it would be worthwhile to invest in robotics, it has to be confirmed that it is superior to conventional techniques. Although numerous retrospective have confirmed equal or even better outcomes for robotic surgery, at present, only one randomised-controlled trial (RCT) has been published in gynaecology comparing laparoscopic and robotic sacrocolpopexy. This disadvantage, however, may be resolved in the near future if more RCTs are conducted.
Learning and training
It is assumed that robotic surgery is associated with a less steep learning curve than conventional laparoscopy, owing to the more intuitive handling of robotic instruments and three-dimensional vision. In fact, in-vitro studies comparing learning curves for laparoscopically and robotically performed exercises (e.g. knot tying or paper cutting) revealed faster learning curves and better performances in the robotic groups. Differences in learning curves were most significant for surgeons without, or with less, surgical experience compared with experienced laparoscopic surgeons. If surgeons are experienced in laparoscopy, usage of the robot could improve ergonomics of motion. This, in turn, may be especially useful in complex procedures within limited workspaces, potentially leading to a reduction of collateral tissue damage. Robotic surgical training is associated with a higher feeling of mastery, familiarity, self-confidence and less difficulty than conventional laparoscopy. Furthermore, training with the robot results in a better stress profile and decreased workload compared with laparoscopy training. One obvious limitation of in-vitro studies is the limited transferability to real operating room scenarios, as usually only a few, repetitive tasks are investigated, which contrasts with the often complex nature of procedures. Nonetheless, because of safety concerns and extensive time required for acquisition of skills, in- vitro training is an important tool before surgeons can operate on patients. Several types of robotic in-vitro training modalities exist, including pelvic trainer in a dry lab, virtual reality trainer, animal models or training with human cadavers, with each of them having particular advantages and disadvantages. In addition to in-vitro skill acquisition, the process of learning robotic surgery involves much more personnel and financial effort. Lenihan et al. described the process of introducing da Vinci ® surgery in their hospital. First, the primary surgeons and the lead operating room technician visited an Intuitive Training Centre, where they were trained in all aspects of set-up, operation and breakdown of the da Vinci ® system. Additionally, the primary surgeons underwent computer-based skill training, observed cases and participated in 2 days of porcine laboratory training before operating on patients. Second, all key primary team members observed cases at an institution already carrying out robotic surgery. Third, company representatives did on-site setups and breakdowns of the robot before the first case. Finally, the first three human procedures were proctored, and technical representatives were present in the operating room for the first 20 cases. Therefore, the whole operating team, in addition to the surgeons and medical technicians, must receive special training. As a result, several learning curves exist for set-up time (preparation and activation of the robot), docking time (positioning and installing of the robot) and console time (actual time needed to complete the robotic procedure). It can be assumed that the learning curve for set-up time and docking time improve rapidly when working in a high-volume setting with a committed team. Published data about learning curves indicate that operative time improved after 20 cases (hysterectomy and pelvic-aortic lymphadenectomy for endometrial cancer), 20 cases (hysterectomy for benign gynaecological diseases and myomectomies), and 50 cases (major benign gynaecological surgery). The surgeons in these studies, however, had previous experience in laparoscopy. Hence, laparoscopically inexperienced surgeons may need more cases to reduce and stabilise the operative time. Further studies need to investigate these learning curves, which could than serve as an orientation for surgeons without any previous experience in advanced laparoscopy. The information obtained from these studies may be particularly helpful for surgeons currently conducting procedures, mainly through an open approach and thinking about adoption of robotic surgery, to offer their patients the benefits of minimally invasive surgery.
Costs
A reliable statement about the expected costs for hospitals aiming to introduce robotic surgery is difficult to make, as various components influence cost calculations, including factors related to hospital and healthcare systems. Cost calculations can be approached in different ways, depending on inclusion or exclusion of the initial purchase costs of the robot, the inclusion of societal costs associated with lost work time of the patient or, in general, on the parameters included in the direct and indirect operating costs. Therefore, studies concerned with costs can only provide an orientation about different aspects, which must be taken into account for calculations ( Table 2 ). Some costs, such as purchase and maintenance costs and costs of disposables, are calculable. The mean purchase price of the da Vinci ® S HD is $1.65 million, with an annual maintenance cost of $149 000 a year for years 2–7. In 2010, the cost of the newest da Vinci ® Si Surgical System was 1.69 million Euro plus tax. An examination of all cost studies of robotic procedures published between 2005 and 2010, including 20 types of surgery, revealed that, on average, the additional cost was about $1600 and about $3200 when the amortized costs were included, respectively. In general, if the purchase and maintenance costs are included in calculations, the costs per procedure vary, depending on the number of procedures performed per month and year, respectively. In a cost-calculation model, the additional cost per procedure decreases when the number of cases performed per month increases ($2814 for 12 cases per month; $1939 for 18 cases per month and $1090 for 32 cases per month). In another calculation, the amortization costs, maintenance costs, and the cost of disposables, were included. Again, the cost per procedure decreases when the number of cases performed per year increases (34,500€ for 10 procedures per year; 8,900€ for 50 procedures per year and 4100€ for 200 procedures per year). Since the costs of disposables increases with the number of procedures performed per year, a compromise must be found between the cost per procedure and the overall cost. On the one hand, a low number of cases make every procedure expensive because of the distribution of the amortization and maintenance costs. On the other hand, a high case volume causes high cost of disposables. In his calculation, Cormier estimates the lower and upper threshold at 100 and 250 procedures to reach a compromise between cost per procedure and overall costs. The disposables can be divided into different categories: draping for the system; EndoWrist instruments (every instrument can be used only 10 times, after which it has to be exchanged); and the accessories that are specific to the da Vinci ® system, including small items that are added to the instruments (e.g. tips and tip covers, reducers). In cost-calculation models, reduction of cost of disposables was one main factor for making the robotic approach less expensive than other approaches, and therefore economically attractive. Since the da Vinci ® Surgical System is currently the only available robotic system of its kind, no price competition exists, making reduction of costs unlikely in the near future. Cost can, however, also be saved through reduction of disposables used and through reduction of operation time, which is likely to occur after completing the initial learning curve of both the surgeon and the theatre stuff concerned with the device set-up. As costs vary between procedures and depend on many different factors, however, it is difficult to draw a general conclusion about the exact amount of costs associated with robotic surgery. Prospective, RCTs are needed to compare costs between different surgical approaches and different procedures to determine operations where robotic surgery can be used cost effectively. Furthermore, in addition to cost effectiveness, prospective studies must prove the efficacy of robotic surgery so that maybe even higher costs would be justified if this approach provides the best possible care for patients.
