Training for laparoendoscopic single-site surgery and natural orifice transluminal endoscopic surgery

Authors


Ithaar H. Derweesh, MD, Division of Urology, Moores UCSD Cancer Center, 3855 Health Sciences Drive, Mail Code 0987, La Jolla, CA 92093-0987, USA.
e-mail: iderweesh@gmail.com

Abstract

A combination of refinements in laparoscopic instrumentation and increasing surgical experience has driven innovation in the area of laparoendoscopic single-site surgery (LESS) and natural orifice transluminal endoscopic surgery (NOTES). By combining working ports and the extraction incision into one site, LESS allows access to the peritoneum with fewer incisions and less scarring than the traditional multiport laparoscopic technique. Reduced incisional morbidity and improved cosmesis have sparked a growing interest in the utilization of these techniques to perform urological surgery. Mastering of the technique requires training and repetition to develop the muscle memory required to perform these challenging procedures. Although there has been an explosion of literature published about initial experiences with LESS and NOTES, little has been written about training and implementation of this approach. Here, we describe our institutional experience and the essential elements of a LESS and NOTES training curriculum and offer some insight into establishing a successful programme.

Abbreviations
LESS

laparoendoscopic single-site surgery

NOTES

natural orifice transluminal endoscopic surgery

MIS

minimally invasive surgery

IRB

Institutional Review Board

INTRODUCTION

Since the early 1990s, with the introduction of complex laparoscopic techniques into the surgical armamentarium, laparoscopy has been a rapidly evolving area of urology [1]. As experience has increased and laparoscopic instrumentation has improved, an innumerable array of more complex procedures has been reported which has conferred the benefits of minimally invasive surgery (MIS) – namely, improved cosmesis, accelerated recovery and decreased analgesic requirements [2,3]. A combination of refinements in laparoscopic instrumentation and increasing surgical experience has driven innovation in the area of laparoendoscopic single-site surgery (LESS) and natural orifice transluminal endoscopic surgery (NOTES) [4–6].

LESS allows access to the peritoneum with fewer incisions and less scarring than the traditional multiport laparoscopic technique. Reduced incisional morbidity and improved cosmesis have sparked a growing interest in the utilization of the technique to perform urological surgery [4,7–9]. NOTES involves the intentional puncture of one of the viscera (e.g. stomach, rectum, vagina, urinary bladder) with an endoscope to access the abdominal cavity and perform intra-abdominal operations [6]. It offers the advantages of MIS in addition to eliminating trauma to the abdominal wall and the attendant sequelae of abdominal wall incisions or hernias, and hence reduction in visible scars and in postoperative pain [10–16]. Although there has been an explosion of literature published about initial experiences with LESS and NOTES, little has been written about training and implementation of this approach. Herein, we describe essential elements of a LESS and NOTES training curriculum, key instruments, training tips and pitfalls, and collaboration ideas that will help establish a successful programme. We will highlight our institutional experience and programme with training residents and fellows (a total of 11 have undergone training in LESS/NOTES procedures) following a clearly delineated algorithm of a didactic introduction, inanimate training and live animal laboratory experience.

GETTING STARTED

It is important to understand the endpoint or goal of any new skill set. Although a number of LESS procedures have been described, for most surgeons these techniques will be immediately applicable to ablative upper tract surgery: total/radical nephrectomy, renal cryoablation, cyst decortication and adrenalectomy. As experience has expanded, LESS has been applied to reconstructive urological procedures such as pyeloplasty, partial nephrectomy and sacrocolopexy [17]. Before beginning human investigation with LESS or NOTES, we strongly suggest investigators adopt the ASGE/SAGES Working Group recommendations for a multidisciplinary team possessing advanced therapeutic endoscopic and laparoscopic skills, by employing a stepwise approach beginning with inanimate trainers to familiarize themselves with the approach, and progressing to animal laboratory experience to train and practise LESS and NOTES techniques and procedures [18]. And finally, Institutional Review Board (IRB) approval must be obtained before introduction of NOTES procedures in human patients.

LESS

LESS is a technically demanding and challenging endeavour that requires a significant commitment. Mastering of the technique requires training and repetition to develop the muscle memory required to perform challenging LESS procedures. Although there has been an explosion of literature published about initial experiences with LESS, little has been written about training and implementation of this approach. As of the time of this paper, only two papers in the literature describe approaches to learning or training for LESS [19,20].

TRAINING APPROACH

Table 1 provides an outline of our institutional LESS training protocol. Beginning adopters of this technology must realize that LESS is different from traditional laparoscopy. In fact, much of what was learned in laparoscopy over time must be modified, if not abandoned. Placement of multiple instruments within a small working space creates significant challenges and initial frustration. Internal and external collisions are more common. Even experienced laparoscopic surgeons will struggle initially with the technique and complain of tight angles and frequent instrument clashes. In accordance with the Fundamentals of Laparoscopic Surgery training curriculum developed by SAGES, we provide a didactic introduction for our LESS training programme by discussing principles, instruments and emerging data [21,22].

Table 1.  Stepwise approach to training and implementation of LESS or NOTES
1. Didactic background (principles, instrument familiarization, review of literature)
2. Hands on box trainers
  a. Inanimate trainer drills
  b. Start with trocars set wide apart (6–7 cm) and reduce linear spread with practice (2–3 cm)
  c. Instruments: start with two regular instruments and then one articulating and one standard
3. Animal lab experience: swine model ideal for LESS renal surgery
4. Hybrid procedures: needlescopic ports or instruments (2–3 mm) to provide additional retraction or triangulation

BOX TRAINERS AND HANDS-ON LAB EXPERIENCE

We progress to hands-on box trainers with inanimate trainer drills (Table 2). A number of box training modules are available on the market to help surgeons develop laparoscopic skills. Standard box trainers or pelvic trainers have multiple ports with standard spacing. These basic models can be easily modified to provide a platform for LESS. By adding additional ports or moving instruments into the same pre-cut port, with or without use of a gel-type port one can develop experience with the technique (Figs 1 and 2). Box trainers can be utilized with or without a camera. Initially, we have found that practice without the camera is preferable at least initially. Several device companies offer table-top training modules that can be easily adapted to LESS training, including Simulab (Seattle, WA, USA) and the FLS Laparoscopic Trainer Box (Venture Technologies, North Billerica, MA, USA). Newer models have more versatility and are ideally suited to begin LESS training. These box trainers combined with a curriculum have an important role in facilitating the development of the psychomotor skills and dexterity required during the performance of laparoscopic surgery [21].

Table 2.  Training tasks
Task 1: Transferring (pegboard): Using two graspers, the operator is required to lift each of six pegs from one board, transfer it to the other grasper, and then place it on the second board. The procedure is then reversed
Task 2: Precision cutting: The participant is required to cut a 4-cm pre-drawn circular pattern out of a 10 × 10 cm piece of double-ply suspended gauze
Task 3: Placement and securing of ligating loop: A pre-tied slip knot (Surgitie, Covidien, Mansfield, MA, USA, or Endoloop, Ethicon Endo-Surgery, Cincinnati, OH, USA) is placed on a circumferential line marked on a tubular foam appendage
Task 4: Extracorporeal knot: This is similar to the previous task except that the suture is 12 cm and an intracorporeal knot is used
Figure 1.

Single incision training with box trainers using ‘Manhattan’ multiport approach.

Figure 2.

Single incision training with box trainers using gel port.

Establishing a training curriculum that guides the surgeon through a series of increasingly difficult tasks is a very effective approach. Our institutional protocol incorporates the FLS-SAGES drill criteria and applies it to LESS skills training (Table 2) [22]. The curriculum is proficiency-based, whereby trainees are oriented to the materials and self-practice until expert-derived performance levels are reached based on timed performance. In our experience, dexterity drills did correlate with incremental skill acquisition and the ability to perform intracorporeal suturing using LESS. These drills help develop successful skills necessary for LESS and multiport laparoscopy including ambidexterity, depth perception, handling materials, manipulating instruments, and using movements that are fluid and rhythmic. While virtual reality trainers have seen a dramatic improvement over the last several years for standard endoscopy and laparoscopy, these platforms are not yet currently available for LESS.

VIVARIUM PROCEDURES

After an inanimate training regimen, we proceed with, and indeed recommend, a regimen that progresses through animal models. Animal training protocols should focus on establishing access, kidney mobilization and medial visceral rotation, hilar dissection and ligation, and specimen extraction. These techniques require close coordination between operating surgeon, assistant and the entire operating room team. We feel that this approach to training is essential to achieve proficiency levels before human application.

PORT PLACEMENT AND LESS ACCESS

Commercially available box trainers can be utilized initially and gradually the ports are brought together. It is important to consider the principle of horizontal port placement within the single incision and use of the vertical dissection plane in order to minimize instrument clashes. Trainees learn to minimize instrument clashes by maximizing the efficiency of their dissection with experience.

There are several commercially available devices for establishing transperitoneal access and pneumoperitoneum. Initially we preferred utilizing separate trocars placed individually through the fascia, all via a single 3- to 4-cm skin incision. The trocar heights were modified to create a ‘Manhattan’ effect which helps to minimize external collisions (Fig. 1). Others have also described multiple fascial punctures through one skin incision, either alone or in combination with use of additional transabdominal sutures to stabilize the target organ. Surgical device makers have recently introduced a number of LESS platforms that offer a low profile, attached CO2 gas inflow and a reliable way of maintaining pneumoperitoneum through a seal. A number of products are available including tri and quad ports and gel-type ports. Some of the novel devices include the Unix-X (Pnavel Systems, Brooklyn, NY, USA) and the AnchorPort, TriPort and R-port devices (Advanced Surgical Concepts, Bray, Co. Wicklow, Ireland). Additionally, the SILS port (Covidien, Mansfield, MA, USA) is a flexible device with three distinct openings that is placed at the umbilicus and leaves only a small incision. The standard GelPort (Applied Medical, Rancho Santa Margarita, CA, USA) has also been used by a number of investigators for LESS access [9]. We recommend that emerging LESS adopters familiarize themselves with a variety of different platforms in dry and pre-clinical live procedures in order to choose the platform(s) they find most comfortable with prior to human application.

INSTRUMENTATION AND LESS STRATEGY

The technology of the instrumentation is constantly changing and each surgeon will develop preferences as experience increases. We have found extra-long instruments useful to create height differences and minimize external collisions. For example we use the extra-long tip on the suction irrigator, extra-long ultrasonic shears or sealants (harmonic scalpel, Enseal, Ethicon Endo-Surgery, Cincinnati, OH, USA) and long scissors, and non-locking atraumatic deBakey forceps. Articulating instruments including flexible-tip cameras and rotating scissors, needle drivers and graspers can also help with intracorporeal triangulation.

Needlescopic ports and instruments can offer a bridge to LESS. These devices are <3 mm in diameter and can be used with or without a traditional trocar. They offer the surgeon ability to triangulate instruments as he or she acquires experience with LESS techniques. Instrument strength and functionality were limited in some of the instruments until recently. They do offer the ability for limited dissection and retraction with the advantage of triangulation. Scars resulting from these instruments are nearly invisible at 6 months according to standardized dermatological scar scales [23,24].

In teaching as well as in our clinical experience, we have found it useful to begin initially with two basic straight instruments. While these instruments may sometimes restrict freedom of movement especially in more complex manoeuvres (upper-pole intracorporeal suturing for instance), we feel that preserving operator familiarity is an important first step in mastering the LESS approach. As experience increases, we have gradually incorporated flexible and reticulating instruments into our training and clinical armamentarium, and then moved to a single straight grasper with articulating scissors in the dominant hand. With practice, one will notice some important differences with respect to standard laparoscopy. Due to the proximity of the instruments, internal clashes are quite common as we have mentioned. In addition, coordinated movements with the camera holder are necessary to prevent camera image smearing. The surgeon’s hands and instruments should move deliberately – somewhat slower than in standard laparoscopy and in unison when possible. The manoeuvres will help prevent the instruments from getting lost, injuring abdominal viscera, and will help maintain orientation. At times, instrument crossing is required to provide adequate retraction in the appropriate vector; however, we try to keep this to a minimum. Other investigators have recently evaluated the use of curved or flexible instruments for LESS and have found pre-bent instruments advantageous for this approach. Stolzenburg et al. [25] found pre-bent instruments had a significant advantage over flexible instruments in terms of time required and a decreased error rate to perform a laparoscopic nephrectomy in a pig model.

FUTURE DIRECTIONS

A variety of different strategies are being developed to facilitate LESS training. These include three-dimensional imaging technology, improved optics and use of advanced simulation. Kommu et al. [26] have described a box model with a three-dimensional image acquisition system that was used to test subjects in basic skills, dorsal vein complex ligation and a sutured urethral anastomosis in a LESS model. Candidates undergoing the expanded imaging protocol acquired target competence for dorsal vein complex ligation 2.3 times quicker and urethral anastomosis 2.8 times quicker than the corresponding two-dimensional only group. The tandem two-dimensional alternating with three-dimensional views helped to narrow the learning curve for target skill acquisition in the LESS platform. Other advances including flexible-tip cameras and self-cleaning lenses with integrated irrigation–suction, such as in the colonoscope, may help to improve surgical efficiencies during LESS procedures. A number of companies are also working on improving optics technology that will lead to improved image quality and with a smaller footprint. Finally, computer simulation has made great advances in helping surgical trainees and practising surgeons develop, maintain and refine laparoscopic skills. Although there is not yet commercial availability of these systems, it is anticipated that the development of these products as well as adaptation of robotic technology in the LESS arena will be spurred on by increasing adoption of LESS.

NOTES

Kalloo et al. [27] first described NOTES in 2004. Since then, several urology groups have demonstrated that a range of surgical procedures can be performed using a variety of different entry points in a porcine model [28–31]. These include the transvaginal route with a peri-umbilical abdominal trocar for visualization, the combined transgastric–transvaginal routes and a pure transvaginal route [28–33]. Others have described intra-abdominal and thoracic organ visualization through a transvesical route and a combined transvesical–transgastric route, as in cholecystectomy [34–37]. In humans, transvaginal specimen retrieval has been described by several groups, and recently Sotelo et al. [10] reported the first successful transvaginal NOTES radical nephrectomy in a human [38–41]. Although NOTES is in its infancy, it represents the next step in MIS.

TRAINING APPROACH

As described by Sotelo et al. [10], establishing a successful NOTES programme involves a progressive, stepwise approach. As with other innovators and early adopters of this technology, we recommend use of a standardized training programme that focuses on development of a multidisciplinary research team, instrument familiarization, dry labs, simulators and vivarium tasks before moving on to human trials. As with LESS, creating an overall research plan with intermediate and long-term goals with IRB approval will help give structure to this endeavour. At our institution, we have a hybrid (transumbilical camera) NOTES protocol for renal surgery with an Institutional Animal Care and Use Committee approved protocol for training and investigation in a pre-clinical swine model [42].

ESTABLISHING THE TEAM

Establishing a research-oriented, multidisciplinary team is a crucial first step. This will help consolidate the diverse skill set that is needed to be successful with this approach. This team should include general and gynaecological surgery experts, urologists and possibly even gastroenterologists with endoscopic expertise. At our institution, we have collaborated with the general surgery MIS team. The MIS multidisciplinary team had been performing NOTES procedures on animals and had recently applied this expertise to human procedures. The MIS team, with the help of the gynaecological surgeons, has successfully performed transvaginal cholecystectomies and hernia repairs [42,43]. Team meetings helped to establish the overall research plan and establish interim training goals to test proficiency. Meetings were held before specific lab sessions to carefully diagram the planned procedure, discuss the type of access and necessary equipment, and plan for possible anatomical and surgical challenges. This collaboration allowed us to share experience and develop a close working relationship that paid dividends as the endeavour progressed.

INSTRUMENTATION AND FAMILIARIZATION

Although urologists are adept at endoscopic procedures, learning to manipulate multichannel endoscopes represents a new skill set. Videogastroscopes or endoscopes have biplanar controls along with incorporated suction and irrigation features and single or multiple working channels. As with LESS, our NOTES investigational and teaching protocol incorporates a didactic introduction with basic principles and dry lab familiarization with the instruments. It is crucial to become familiar with flexible endoscopes and the commercially available instruments that can be inserted through their working channels (Fig. 3).

Figure 3.

Dual-channel endoscope (Olympus GIF 2T-160, Center Valley, PA, USA).

TRAINING TASKS

Progression through the standard tasks described in the LESS section is often more difficult in the NOTES setting. After instrument familiarization, box trainers help the surgeon begin working in a non-triangulated setting. With a hybrid NOTES approach, the endoscope is placed through the lower portion of the box trainer and one additional port can be used to assist with dissection. Instruments, including graspers and electrocautery devices, are then passed through the endoscope. The secondary port can be used for visualization, retraction or dissection in the surgical field. As experience increased, we moved to pure NOTES tasks. These tasks were modified but similar to those established as benchmarks for LESS, including transferring (pegboard, placed on the back wall of the box to approximate the NOTES environment), precision cutting (pattern cutting) and placement and securing of ligating loop. After box trainers, the focus on training tasks should be based on the research plan and objectives detailed at the start of the programme. Skills must be established in the vivarium. While working with the MIS team, we developed techniques to obtain natural orifice access to the vagina. We have also found that establishing access and being able to complete the tasks or operation often requires innovative use of off the shelf trocars, gel-type ports and/or adjunctive needlescopic instruments.

ESTABLISHING THE ACCESS

Use of box trainers and dry labs helped expedite our learning experience. In the vivarium we performed our NOTES procedures using an umbilically inserted camera for visualization of abdominal natural orifice access; this is a safety procedure mandated by our institution board review committee. As described by Kaouk et al. [41], we transitioned to a vaginally placed gel port through which instruments were inserted into the abdomen to perform urological procedures. Next we will describe establishing our transvaginal access and nephrectomy technique in the training porcine model.

VAGINAL ACCESS AND KIDNEY DISSECTION TECHNIQUE IN PIG MODEL

After general anaesthesia is established, the pig is placed in a supine position with both hind legs abducted. A 12-mm umbilical port is placed per IRB requirement as a safety measure, to assist with visualization and for deployment of the endovascular stapler. Transvaginal access was obtained using a coaxial needle/knife electrocautery and balloon (Boston Scientific, Natick, MA, USA). This device (Fig. 4) includes three parts: a blunt hollow needle which is used to perforate the posterior vaginal cul-de-sac, a guidewire introduced through the needle using Seldinger’s technique to provide access into the abdominal cavity, and a balloon dilator. The balloon is then advanced over the guidewire to dilate the vaginal tract and provide access for a conventional dual channel endoscope (Olympus GIF 2T-160, Center Valley, PA, USA). The balloon is then deflated and removed, and the pig is repositioned to the left flank position. We also place a 15-mm trocar over the endoscope to maintain access.

Figure 4.

Coaxial needle balloon system for NOTES access.

After access is established, monopolar flexible scissors or flexible graspers can be used in the single umbilical port to assist with the renal mobilization. The dissection is initially done along the posterior aspect of the kidney close to the psoas. Next, the colon is mobilized and the dissection progresses from the lower pole to the renal hilum. The ureter is visualized and retracted medially and posterior attachments of the kidney are freed in a medial-to-lateral fashion towards the upper pole using the monopolar scissors inserted through the gastroscope working channel or from the umbilical port. After completion of the posterior dissection, the endoscope is withdrawn to the lower pole and the ureter is retracted laterally. Medial attachments can then be divided to reveal the pedicle, which is dissected free. The endoscope is advanced medially and flexed 90° to face the hilum, and an articulating endoscopic stapler (Endo-GIA, Covidien, or Endopath ETS, Ethicon) can be used to divide the renal vein and artery en bloc. The superior and lateral attachments of the kidney are then freed, and the kidney is placed in a specimen retrieval bag and removed intact transvaginally.

Establishing access is often the most difficult part of the procedure. The pig has a narrow vagina that is often multi-lobulated so that it can be somewhat difficult to establish access in the posterior fornix. Careful attention to creating a small opening or using a 15-mm trocar will help to maintain a pneumoperitoneum in this area. In women, we recommend starting off with older patients and with those who have had prior hysterectomy. In these cases, establishing access through the vaginal cuff is somewhat easier than in younger women. As mentioned earlier, having gynaecologists integrated into the surgical team offers a significant advantage to this approach. Intact specimen retrieval through the vagina helps to maintain the NOTES advantage of no skin incision surgery.

FUTURE TRAINING

Innovations in software, optics and mechanical instrumentation will help drive the future of NOTES. Computer-based, hands-on training with high fidelity to actual procedures will be important to establish basic familiarization with NOTES. Integration of endoscopic training devices and adapted colonoscopy trainers with laparoscopic simulators will help develop proficiency. Typical endoscopy often requires endoscope manipulation with a strong emphasis on rotational movements, and as a result there are a number of limitations in optics and visualization. Steering is by trial and error, and proficiency is gained through experience. Rotation of the camera angle has been shown to decrease surgical efficiency and increase time to complete certain tasks. New robotic and integrated camera-information systems are being developed to correct camera angle and orientation and thereby increase surgical efficiency. Additionally, needlescopic or capsule-type cameras may improve optics [24].

Expanded use of internal retractors may improve the ability of the surgeon to triangulate within the abdomen; the Endograb (Virtual Ports, Misgav, Israel) is one such device [44]. Future NOTES training will also incorporate many of the new robotic and nanotechnology devices being tested. Magnetically anchored and guidance systems are being designed to manoeuvre intra-abdominal instruments by use of an external handheld magnet [17]. Other devices include small robotic instruments that are assembled intracorporeally after transgastric or transvaginal placement. These devices provide the surgeon with flexibility and strength of instruments to assist with both retraction and dissection or suturing. The ability to insert instruments and have the surgeon control them remotely can allow degrees of freedom and triangulation not otherwise possible with a single point of origin. This is an exciting and rapidly progressing area of active research [5].

LIMITATIONS

LESS and NOTES present substantial technical challenges. Establishing instrument triangulation, as with traditional laparoscopy, is often difficult to attain in LESS. This translates into difficulty with suturing and frequent instrument clashes. Articulating or pre-bent instruments are promising in their ability to provide intra-abdominal triangulation. These, however, require substantial training and practice, as the articulating instruments are often counterintuitive in their movements. NOTES presents many surgical challenges as well. In particular it is still highly debated in surgical arenas and lacks long-term data. NOTES entails a steep learning curve because of the required instruments and expertise of working through a natural orifice. Close coordination with gynaecology or general surgery is requisite to help establish safe access and in establishing a successful programme. The nuances of the gastroscope and limited working space combined with unique camera angles further push the surgical envelope.

CONCLUSION

LESS and NOTES present substantial technical challenges, but represent an exciting new area of surgical investigation. As such, establishing an investigational curriculum with stepwise progression through training modules before human application is essential. Before starting a LESS programme or embarking upon human investigation of NOTES, we strongly suggest investigators adopt the ASGE/SAGES Working Group recommendations for establishing a multidisciplinary team possessing advanced therapeutic endoscopic and laparoscopic skills. Establishing an investigationally oriented, multidisciplinary team is a crucial first step that will lead to a successful programme. These recommendations also stress the need for IRB approval, in particular before introduction of NOTES procedures in human patients.

Adopters of LESS should understand that establishing instrument triangulation, as with traditional multiport laparoscopy, is often difficult to attain in LESS. This presents challenges with complex manoeuvres such as suturing and instrument clashes, which may be substantially reduced but not eliminated with increasing experience. Articulating or pre-bent instruments are promising in their ability to provide intra-abdominal triangulation. Extended training with these instruments is recommended. NOTES presents many surgical challenges as well. NOTES entails a steep learning curve because of the required instruments and working through a natural orifice means that the available space limits the number of instruments. Additionally, flexible endoscopes are commonly used which can present angulation and visualization challenges. Overall, training should focus on establishing a multidisciplinary team followed by instrument familiarization, and progression from investigational curriculum, to dry lab and box training modules to vivarium labs and human cases as skills progress.

CONFLICT OF INTEREST

SPS, WB: None. IHD is a consultant for Angiodynamics and Ethicon Endo-Surgery.

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