Training on Minimally Invasive Colorectal Surgery during Surgical Residency: Integrating Surgical Education and Advanced Techniques

Abstract

Surgery is an ever-evolving discipline and continually incorporates new technologies that have improved the ability of the operating room surgeon to perform. The next generation of minimally invasive surgery includes laparoscopic and robotic-assisted procedures. Graduating residents may be expected to have the skills to perform common colorectal procedures using these technologies, and residency programs are developing curriculums to teach these skills. Minimally invasive techniques are challenging and learning only by observation and practice alone is difficult. This requires dedicated training and mentoring.

New simulation methods have been conceived specifically for minimally invasive procedures, and these embrace a combination of virtual reality simulators and box trainers, with animal and human tissue, as well as synthetic materials. The aim of this review is to provide an overview of training in minimally invasive colorectal surgery with a focus on different types of simulators that build the basis to develop and include a multistep training approach in a structured training curriculum for minimally invasive colorectal procedures.

The high level of technical complexity associated with minimally invasive procedures in colorectal surgery requires specific skills dissimilar to those used during conventional surgery. ¹ The learning curve is extended, and, in the light of the current data in the scientific literature, have been estimated as being between 30 and 60 cases. ^{2 3}

Minimally invasive procedures, such as laparoscopic colectomy, low anterior resection, transanal total mesorectal excision (TaTME), or transanal minimally invasive surgery (TAMIS), are technically challenging for a specialist, and frequently being self-taught by senior surgeons. ⁴ There is available evidence that the absence of appropriate training may lead to patient safety compromise. ⁵

Surgical training has traditionally been one of apprenticeship, based on a Halsted's “see one, do one, teach one” classic aphorism, where the surgical trainee is keen to perform surgery under the supervision of an experienced surgeon. ⁶ Ability for minimally invasive procedures needs specific surgical skills to overcome intrinsic technical difficulties, which include two-dimensional vision with loss of depth perception, less range of motion of the instruments when compared with open surgery, impaired tactile sensation, and the disparity between visual and proprioceptive feedback known as the fulcrum effect. ^{7 8}

Currently, there is a gap between expected level and actual practice ⁹ in trainees' performances. Research has demonstrated a deficit in successful performances in numbers of critical laparoscopic colorectal cases by trainees. ^{10 11} Moreover, augmented rates of adverse clinical outcomes at the beginning of the learning curve create ethical questions and underline the demand for solutions to decrease complications and unnecessary conversions to open surgery during the early stage of independent practice. It has also been shown that the surgical theater cannot be the best scenario for a beginner who is learning from the moment that high stress leads to damaging effects on performance. ¹² Additionally, surgical training in the operating room implicates additional costs, estimated in approximately USD $47,979 per year per trainee. ¹³

The challenges that training residents in colon and rectal surgery have to face are significant and simple box trainers are not the ideal minimally invasive colorectal model, because of the need to work in multiple abdominal quadrants, transect and extract often large specimens, and perform bowel anastomosis. ⁶ In this scenario, it is really important to promote the use of advanced training in laparoscopic colorectal surgery, with the evident need to improve the training opportunities. Advanced surgery needs advanced simulation training. Laparoscopic and robotic training not only have changed the traditional Halsted's centennial apprenticeship model, ⁶ but have also induced an urge to development of simulation techniques. Adequate training definitely is the best way to prevent and diminish potential surgical errors. ¹⁴

Overview of Training

Surgical trainees, traditionally learned practices by observation and adoption of Dr. Halsted's methods, studied since the 1940s. ^{9 10} Before his time, there was no formal training programs in surgery, and most surgeons were self-taught. ¹⁵ Dr. Halsted was responsible for training the first generation of modern surgeons, basing his approach on the “pyramid” system of training. His model continues to influence surgical education up to nowadays.

Thereafter, surgical techniques evolved, with the introduction of minimally invasive procedures. New simulation methods were needed, so have recently been specifically developed, specifically in a combination of animal and human tissue, synthetic materials, box trainers, and virtual reality (VR) simulators. ^{16 17}

Animal and human cadaver training models have commonly been used to improve perception of surgical anatomy, to identify dissection planes and to prove tissue handling and complex surgical techniques. ^{18 19} Unluckily, both these models are associated to limitations: they require specialized training setting, are expensive, have poor availability, and each trainee probably can perform only a part of the procedure once.

Box simulators are based on the use of laparoscopic instruments set within a physical box. The advantages of these devices are to provide tactile feedback and to be relatively affordable. On the other hand, they require ongoing maintenance and specific materials, and need feedback from an external trainer.

Modern VR simulators use extremely advanced hardware and software to arrange the most realistic simulation: they have a higher cost, but they can be used not only as a training device but also as a tool to assess surgical skills. In fact, they provide a series of facilities, such as pretask tutorials and feedbacks at the completion of the procedure, and register several parameters like time taken, efficiency of motion, and knot integrity. Using VR simulator systems, the trainer can be monitored easily and remotely. ²⁰

After all, the aim of resident training is to produce a competent, efficient, and honest surgeon and the real challenge is how to motivate residents to meet these standards.

Structure of a Training Curriculum

Nowadays residents may be expected to have the skills to perform common colorectal procedures using minimally invasive techniques, so residency programs have adopted standardized apprenticeship models to teach and access these skills and to secure a curriculum, comprehensive specified operative experience, transparent performance feedback, and optimized clinical outcomes. ²¹ To develop an exhaustive surgical curriculum, it is fundamental that specialty-based knowledge, clinical judgment, adequate technique, and professional skills and behavior must be acquired at each stage to reach high-quality surgical training. ²² Each learner must be able to acquire knowledge without constraints of time and with the option of receiving expert feedback and assistance if required.

Simulators as Part of Surgical Curriculum

A simulator-based curriculum should provide a pretraining education through reading, videos, or live interactions, to recognize the correct and incorrect behavior and avoid significant errors. The learner has to acquire skills progressively, from simple to complex situations in an organized plan. Generally, good practice suggests starting with low-tech trainers to practice building block skills, such as, knot tying, cutting, and suturing.

For high-tech trainers, as VR simulators, it is reasonable to begin with simple depth-perception and hand–eye coordination exercises before progressing to complex procedures. Most VR simulators provide a proximate feedback to the trainees aiding them learning. ^{17 23}

Many authors have described simulation-based curriculum for laparoscopic surgery and particularly for minimally invasive colorectal skills. ^{19 24} For instance, general surgical curriculum in the U.K. is based on the Intercollegiate Surgical Curriculum Program (ISCP) which was launched in 2007 and is now in its 10th version. The ISCP provides the U.K. model for surgical training from university, through to consultant level. It achieves this through a syllabus that lays down the standards of specialty-based knowledge, clinical judgment, technical, and operative skills, which must be acquired at each stage to progress. The aims of the curriculum are to ensure the highest standards of surgical practice in the U.K. by delivering high-quality surgical training and to provide an excellent care for the surgical patient. ²²

In regards to surgical training in the U.S., the American College of Surgeons (ACS) has developed the ACS Fundamentals of Surgery Curriculum. It is an online curriculum, highly interactive, case-based, that addresses the essential content areas that all surgical residents need to master in the early years of training. The curriculum was developed by the ACS Division of Education and includes more than 110 simulated case scenarios in which residents have to evaluate data, recognize and assess symptoms and signs, to order appropriate tests and procedures, and to initiate appropriate actions.

Colorectal Societies and Training Opportunity

International Colorectal Surgery Societies have been actively providing support for the education of respective members specializing in colon and rectal surgery, general surgeons, surgical residents, and medical students. With new developments in minimally invasive techniques and in surgical education, they offer educational tools and activities designed for acquisition of medical knowledge and technical skills. These tools and activities include hands-on courses, cadaver laboratories, and some examples which are reported in Table 1 .

Table 1. Tools and activities offered by Colorectal Surgery Societies.

	Country	Duration	Receivers	Aim (skills)	Online learning courses	Course
ESCP	Europe	Days	Junior and experienced trainees	Basic laparoscopic skills (e.g., laparoscopic right hemicolectomy and left-sided colonic mobilization)	–	• Lectures and videos • Wet laboratory • Cadaver laboratory
ASCRS	U.S.	Variable	Junior and experienced trainees	Online learning program and self- assessment instrument	• CARSEP • CREST	• Texts and lectures • Hands-on course
ACPGBI	U.K.	Days	Junior and experienced trainees	Full range of colorectal surgery procedures; laparoscopic pelvic floor surgery.	–	• Texts and lectures • Hands-on course
CSSANZ	Australia and New Zealand	2 years	Fellows	Full range of colorectal surgery procedures; laparoscopic pelvic floor surgery.	–	• Hands-on course • Journal Club (monthly) • Training weekend (annual) • One research year (optional)

Abbreviations: ACPGBI, Association of Coloproctology of Great Britain and Ireland; ASCRS, American Society of Colorectal Surgery; CSSANZ, Colorectal Surgical Society of Australia and New Zealand; ESCP, European Society of Colorectal Surgery.

European Society of Colorectal Surgery

This program is designed for junior trainees in colorectal surgery and runs a colorectal laparoscopic basic skills course aimed to perform laparoscopic right hemicolectomy and left-sided colonic mobilization. It was hoped that those attending the course would be able to acquire new operative techniques and an appreciation of the surgical strategies. The daily courses comprise lectures and video presentations from an international invited faculty, hands-on operative skills exercises in the wet laboratory, and hands-on operations in the cadaver laboratory. ²⁵

American Society of Colorectal Surgery (ASCRS): The program of the ASCRS' online learning center includes two online learning courses: CARSEP and CREST.

• CARSEP is a self-assessment instrument, consisting of 250 multiple-choice questions, a photo quiz, and a pre- and posttest for self-assessment, answers, feedback, and references.

• CREST is a dynamic online learning program offering numerous fundamental topics of colorectal disease: perioperative, malignancy, anorectal disease, benign disease, pelvic floor, and miscellaneous. Each topic offers learning materials in a variety of medias, such as narrated presentations, videos, journal articles, and book chapters, to encourage learning in the way users find the most helpful. A postassessment and evaluation are available after the user completes all of the required content in each topic. ²⁶

ACS/Association of Program Directors in Surgery (APDS) Surgery Resident Skills Curriculum: The ACS/APDS Surgery Resident Skills Curriculum was developed jointly by the ACS and the APDS and includes three phases. Phase 1 includes 20 modules that address basic surgical skills. Phase 2 includes 15 modules that address advanced skills and procedures, and Phase 3 includes 10 modules that address team-based skills. ²⁶

Colorectal Surgical Society of Australia and New Zealand: In Australia and New Zealand, a formal colorectal surgical training program is run by the Australia and New Zealand Training Board in Colon and Rectal Surgery (ANZTBCRS). The purpose of the training is to provide the structured educational and training skill necessary to achieve expertise in the understanding, diagnosis, and management of diseases of the colon, rectum, small bowel, and anus. The program offers two clinical years of colorectal surgical training at ANZTBCRS-accredited units throughout Australia and New Zealand, with the expectation of 1 year outside of a trainee's home state/country to increase their experience in minimally invasive colorectal procedures. Trainees have to register completed work and this is reviewed by the Board to warrant that training exposure to different cases is suitable. Some trainees can broad an additional research year as part of their training. ²⁷

How Do We Train: State of the Art

Simulators are often described as low-tech versus high-tech. Low-tech simulators vary from plastic models of organ systems to basic plastic manikins and skills trainers. Human cadavers and animal tissue are also included in this group. These simulators are not computer-driven, are usually of low cost and low maintenance. High-tech simulators are computer-based, utilizing advanced hardware and software to achieve realistic simulation. Simulators can also be classified on the degree of fidelity based on characteristics like tactile feedback, visual clues, and interaction with the trainee ²⁸ ( Table 2 ).

Table 2. Main features of different types of simulators.

Type	Trainee population	Skills	Advantages	Limitations	Cost
Low fidelity
Physical simulator – Box trainers	Beginners	• Hand–eye coordination • Cutting • Suturing • Bimanual dexterity	• Task-training • Sensory feedback • Portable • Used repeatedly by multiple users	• Limited Realism/ haptics • No inherent metrics • Requires direct observation and supervision by trainer	Set-up: Low Ongoing: Low
Human cadaver and animal models  - Porcine  - Canine  - Bovine  - Baboon  - Avian	Beginners to advanced	• Open skills • Laparoscopic skills • Endoscopic skills • Vascular procedures	• Task, procedure, and team training • Best anatomic and clinical-like model • Realistic haptic feedback	• Loss of tissue fidelity compared with live model • Limited availability • Not portable • Single use • Ethical and disease transmission concerns • Operative facilities and funeral service	Set-up: High Ongoing: High
Harvested tissue model  - Animal tissue attached to synthetic frames	Beginners to intermediate	• Skills that require repetition	• May provide haptic feedback	• Limited procedures • Requires special facilities for storage	Set-up: Low Ongoing: Very low
High fidelity
Computer simulation  - Virtual reality simulators	Beginners to advanced	• Recording of training performance for objective evidence of skill performance	• Task and procedure training • Provides detailed metrics • May be portable	• May have limited haptics (depending on type)	Set-up: High Ongoing: Moderate
Hybrid models  - Combined virtual reality and physical simulator	Intermediate to advanced	• Advanced surgical skills	• Procedure and team training • Simulates entire operative experience	• Requires facility, time, and effort in preparation and maintenance • Not portable	Set-up: High Ongoing: High (Minor compared with cadaver)

Korndorffer et al ²⁹ found out that training to a prearranged experienced level on a video-trainer suture model allows trainees to translate skills into better quality operative performance. The usefulness of VR simulator training for minimally invasive procedures has been validated by several randomized controlled trials, and these studies have shown that there is a strong evidence (grade IA–IIB) to support the use of VR simulators in training. ³⁰ Indeed, Lucas et al ³¹ observed that surgical skills acquired by means of training on a VR laparoscopic simulator (LAP Mentor) are not procedure-specific but improve overall surgical skills, thereby translating into superior performance of an unrelated live laparoscopic urological procedure.

Low-fidelity trainers: Low-fidelity trainers embrace simple devices like knot-tying boards, tissue models to practice dissection and suturing, and box trainers. They use surgical instruments and a camera/video system. These devices are designed to improve hand–eye coordination, cutting, suturing, and bimanual dexterity providing sensory feedback that allows trainees to practice with instruments, needles, and tissue handling. These simulators are typically portable, associated to low maintenance, of relatively lower cost, and can be used repeatedly by multiple users.

High-fidelity trainers: High-fidelity trainers are based in VR simulators and live animal models. VR trainers allow the trainee to interact with a computer-generated environment that reproduces situations and procedures with possible complications that may occur during the procedures. One of the main advantages of VR systems is their ability to evaluate detailed objective data on a vast array of parameters for every session with the simulator: this consents to monitor trainees' progress.

One of the first presented laparoscopic trainers was the Minimal Invasive Surgery Trainer-Virtual Reality . This device had simple imagery with tasks related to placement and transfer of virtual objects. Another one is the LapSim system, which is a commonly used VR simulator and has a more developed graphic interface that allows to simulate laparoscopic cholecystectomy, colectomy, hernia repair, and bariatric procedures. Hybrid VR or augmented reality systems, such as HapticaProMis , are different kinds of devices which combine anatomic models with laparoscopic monitors. Live animal models are also considered of high fidelity and have been used for decades to teach, develop, and test surgical innovations for both laparoscopic and open surgery. These models are perfect to teach dissection, tissue handling, and complex surgical procedures. ³²

The Example of TaTME: Our Experience

TaTME is one of the most challenging and advanced surgical techniques for rectal dissection and mobilization. The interest for TaTME has been spread rapidly worldwide. It was initially pioneered for rectal cancer, ³³ but currently the procedure has also been adopted for benign conditions such as ulcerative colitis or polyposis ( Fig. 1 ). ^{34 35}

Fig. 1.

Surgeons at work during the transanal total mesorectal excision (TaTME) course.

In TaTME, there are several technical challenges, such as the unusual view and interpretation of the anatomy from below and, moreover, identifying correct tissue plans can be difficult. Additionally, operating through a single port involves significant technical skills. Prior training in laparoscopic and rectal surgery is a necessary prerequisite for TaTME training.

In the light of the above, we propose a workshop TaTME course, which had the first edition in 2015, in our simulation center. This 2-day course aims colorectal surgeons who are experienced in laparoscopic and/or robotic rectal surgery, and ideally also experienced with transanal surgery, for example transanal endoscopic microsurgery and TAMIS. The course involves a multistep training approach, embracing in-depth didactic lectures, live case observation, explanatory videos, and hands-on training on simulators as well as on human cadavers under the supervision of experienced surgeons with the technique.

Future Directions

Surgical simulation has undergone a substantial transformation since the early 1990s, evolving from manikins and plastic bench-top kits to three-dimensional printing and patient-specific VR systems. This evolution has led to the development of devices that are useful to both experienced and novice surgeons. Traditionally, simulators like cadavers and bench-top models were mainly used to train novice surgeons. However, new devices are an important tool also for expert surgeons to practice for unique surgical conditions specific to the patient. These new simulators are redefining the role of simulations, expanding their use from training to preoperative planning.

Different meta-analyses have determined that implementing simulation to conventional surgical training results in enhanced surgical performance, reduced duration of surgical procedures, decreased error rate, and improved patient outcomes. ^{36 37} Other clinical trials focusing on VR simulators of laparoscopic surgery have similarly validated that the use of these systems reduced surgical complication rates, improved the development of trainee surgical skills, and shortened operative times overall. ^{24 38} There is a current need to integrate these simulators into structured surgical training curricula, while many surgical workshops are organized annually to teach specific surgical procedures on simulators, the presence of longitudinal courses incorporating simulators is lacking.

Conclusion

Standard surgical training has traditionally been one of apprenticeship, where the surgical trainee learns to perform surgery under the supervision of a trained surgeon, following Halsted's classic scheme. This process of learning is time-consuming, costly, and increases the risk of adverse clinical outcomes for the patient. In the light of the above, the use of simulation in surgical training, using both low- and high-fidelity trainers, plays a fundamental role in the curriculum to improve the clinical environment and make the learning environment safer and more efficient. The intent of surgical simulation is to allow the trainee to acquire critical skills in a safe environment that does not threaten patients' safety. In conclusion, a multistep training approach, embracing in-depth didactic lectures, live case observation, explanatory videos, and hands-on training on simulators and on human cadavers under the supervision of an experienced surgeon should be applied and included in a structured training curriculum for minimally invasive colorectal procedures.