Simulators in surgery

Recent Advances in Smart Epidural Spinal Needles

Lumbar puncture is a minimally invasive procedure that utilizes a spinal needle to puncture the lumbar epidural space to take a sample from the cerebrospinal fluid or inject drugs for diagnostic and therapeutic purposes. Physicians rely on their expertise to localize epidural space. Due to its critical procedure, the failure rate can reach up to 28%. Hence, a high level of experience and caution is required to correctly insert the needle without puncturing the dura mater, which is a fibrous layer protecting the spinal cord. Failure of spinal anesthesia is, in some cases, related to faulty needle placement techniques since it is blindly inserted. Therefore, advanced techniques for localization of the epidural space are essential to avoid any possible side effects. As for epidural space localization, various ideas were carried out over recent years to provide accurate identification of the epidural space. Subsequently, several methodologies based on mechanical and optical schemes have been proposed. Several research groups worked from different aspects of the problem, namely, the clinical and engineering sides. Hence, the main goal of this paper is to review this research with the aim of remedying the gap between the clinical side of the problem and the engineering side by examining the main techniques in building sensors for such purposes. This manuscript provides an understanding of the clinical needs of spinal needles from an anatomical point of view. Most importantly, it discusses the mechanical and optical approaches in designing and building sensors to guide spinal needles. Finally, the standards that must be followed in building smart spinal needles for approval procedures are also presented, along with some insight into future directions.

Recent advances in benign gynecological laparoscopic surgery

Minimally invasive surgery continues to transform the field of gynecological surgery and is now the standard of care for the surgical treatment of many diseases in gynecology. Owing to minimally invasive surgery's clear advantages, new advances in technology are being employed rapidly and enabling even the most complicated procedures to be performed less invasively. We examine recent literature on minimally invasive surgical innovations, advances, and common practices in benign gynecology that, from our point of view, made an impact on the way laparoscopic surgery is performed and managed in the last decade.

Striving for Better Medical Education: the Simulation Approach

Medical simulation is a rapidly expanding area within medical education due to advances in technology, significant reduction in training hours and increased procedural complexity. Simulation training aims to enhance patient safety through improved technical competency and eliminating human factors in a risk free environment. It is particularly applicable to a practical, procedure-orientated specialties.

Simulation can be useful for novice trainees, experienced clinicians (e.g. for revalidation) and team building. It has become a cornerstone in the delivery of medical education, being a paradigm shift in how doctors are educated and trained. Simulation must take a proactive position in the development of metric-based simulation curriculum, adoption of proficiency benchmarking definitions, and should not depend on the simulation platforms used.

Conversely, ingraining of poor practice may occur in the absence of adequate supervision, and equipment malfunction during the simulation can break the immersion and disrupt any learning that has occurred. Despite the presence of high technology, there is a substantial learning curve for both learners and facilitators.

The technology of simulation continues to advance, offering devices capable of improved fidelity in virtual reality simulation, more sophisticated procedural practice and advanced patient simulators. Simulation-based training has also brought about paradigm shifts in the medical and surgical education arenas and ensured that the scope and impact of simulation will continue to broaden.

Virtual reality-based assessment of basic laparoscopic skills using the Leap Motion controller

BACKGROUND

The majority of the current surgical simulators employ specialized sensory equipment for instrument tracking. The Leap Motion controller is a new device able to track linear objects with sub-millimeter accuracy. The aim of this study was to investigate the potential of a virtual reality (VR) simulator for assessment of basic laparoscopic skills, based on the low-cost Leap Motion controller.

METHODS

A simple interface was constructed to simulate the insertion point of the instruments into the abdominal cavity. The controller provided information about the position and orientation of the instruments. Custom tools were constructed to simulate the laparoscopic setup. Three basic VR tasks were developed: camera navigation (CN), instrument navigation (IN), and bimanual operation (BO). The experiments were carried out in two simulation centers: MPLSC (Athens, Greece) and CRESENT (Riyadh, Kingdom of Saudi Arabia). Two groups of surgeons (28 experts and 21 novices) participated in the study by performing the VR tasks. Skills assessment metrics included time, pathlength, and two task-specific errors. The face validity of the training scenarios was also investigated via a questionnaire completed by the participants.

RESULTS

Expert surgeons significantly outperformed novices in all assessment metrics for IN and BO (p < 0.05). For CN, a significant difference was found in one error metric (p < 0.05). The greatest difference between the performances of the two groups occurred for BO. Qualitative analysis of the instrument trajectory revealed that experts performed more delicate movements compared to novices. Subjects' ratings on the feedback questionnaire highlighted the training value of the system.

CONCLUSIONS

This study provides evidence regarding the potential use of the Leap Motion controller for assessment of basic laparoscopic skills. The proposed system allowed the evaluation of dexterity of the hand movements. Future work will involve comparison studies with validated simulators and development of advanced training scenarios on current Leap Motion controller.

The Effect of Mixed-Task Basic Training in the Acquisition of Advanced Laparoscopic Skills

The aim of this study was to assess whether mixed practice of basic tasks on a virtual reality (VR) simulator improves the performance of advanced tasks on the same device used for training as well as on a video trainer (VT). Thirty-six novices were allocated into 3 equal groups. Each group practiced on different combinations of basic tasks on a VR simulator: (A) peg transfer, (B) peg transfer and clipping, and (C) peg transfer, clipping, and cutting. Before and after training, each group performed a laparoscopic cholecystectomy (LC) scenario on the simulator and intracorporeal knot tying (KT) on a VT. Assessment metrics included time, instrument’s path length, penalty score, and hand motion synchronization. Results showed that for the common training tasks, plateau values were statistically equivalent for most assessment metrics ( P > .05). For LC, all groups showed significant performance improvement ( P < .05). For KT, group C improved significantly in pathlength ( P < .005), penalty score ( P < .05), and hand motion synchronization ( P < .05); the other groups failed to show an improvement ( P > .05). In conclusion, training on different VR tasks seems to have no effect on the performance of more demanding tasks on the same device. However, the number of different tasks practiced on the VR simulator seems to favorably affect the performance of advanced tasks on the VT.

The clinical safety of performing laparoscopic gastrectomy for gastric cancer by trainees after sufficient experience in assisting

BACKGROUND

Laparoscopic gastrectomy (LAG) is increasingly performed to treat gastric cancer. However, the procedure remains complicated, and an optimal system for educating clinicians about LAG has not been established.

METHODS

Our training system centers on understanding the anatomical appearance under laparoscopy and the standardized steps of LAG, including the roles of the scopist and the assistant. The trainees participated in LAG procedures as a scopist and an assistant in 30-35 cases, before conducting their first LAG case. The data of 788 consecutive patients with early gastric cancer who underwent LAG were also reviewed.

RESULTS

During the study period, nine trainees performed a total of 215 LAG (27.3 %) with trainers, while 563 LAG were conducted by the two trainers (71.4 %). The surgical outcomes including operative time, blood loss, and retrieval of lymph nodes were almost equivalent for both the trainers and the trainees. The total experience among the trainees as scopist and as first assistant was 45.0 and 41.4 cases, respectively, and the trainees had experienced 33.8 cases as a scopist and 35.3 cases as an assistant before they performed their first LAG as an operator. After commencing experience as an operator, the average operation time of the trainees reached that of the trainers within six cases and their learning curve reached a plateau.

CONCLUSIONS

Our training system based on attaining sufficient experience as an assistant and scopist in the simulation of a LAG procedure was effective for ensuring clinical safety for LAG performed by a trainee with experienced surgeons.

Towards a realistic in vitro experience of epidural Tuohy needle insertion

The amount of pressure exerted on the syringe and the depth of needle insertion are the two key factors for successfully carrying out epidural procedure. The force feedback from the syringe plunger is helpful in judging the loss of pressure, and the depth of the needle insertion is crucial in identifying when the needle is precisely placed in the epidural space. This article presents the development of two novel wireless devices to measure these parameters to precisely guide the needle placement in the epidural space. These techniques can be directly used on patients or implemented in a simulator for improving the safety of procedure. A pilot trial has been conducted to collect depth and pressure data with the devices on a porcine cadaver. These measurements are then combined to accurately configure a haptic device for creating a realistic in vitro experience of epidural needle insertion.

Objective assessment of the core laparoscopic skills course

Objective. The demand for laparoscopic surgery has led to the core laparoscopic skills course (CLSC) becoming mandatory for trainees in UK. Virtual reality simulation (VR) has a great potential as a training and assessment tool of laparoscopic skills. The aim of this study was to determine the role of the CLSC in developing laparoscopic skills using the VR. Design. Prospective study. Doctors were given teaching to explain how to perform PEG transfer and clipping skills using the VR. They carried out these skills before and after the course. During the course they were trained using the Box Trainer (BT). Certain parameters assessed. Setting. Between 2008 and 2010, doctors attending the CLSC at St Georges Hospital. Participants. All doctors with minimal laparoscopic experience attending the CLSC. Results. Forty eight doctors were included. The time taken for the PEG skill improved by 52%, total left hand and right hand length by 41% and 48%. The total time in the clipping skill improved by 57%. Improvement in clips applied in the marked area was 38% and 45% in maximum vessel stretch. Conclusions. This study demonstrated that CLSC improved some aspects of the laparoscopic surgical skills. It addresses Practice-based Learning and patient care.

Simulation in surgery: a review

The ability to acquire surgical skills requires consistent practice, and evidence suggests that many of these technical skills can be learnt away from the operating theatre. The aim of this review article is to discuss the importance of surgical simulation today and its various types, exploring the effectiveness of simulation in the clinical setting and its challenges for the future. Surgical simulation offers the opportunity for trainees to practise their surgical skills prior to entering the operating theatre, allowing detailed feedback and objective assessment of their performance. This enables better patient safety and standards of care. Surgical simulators can be divided into organic or inorganic simulators. Organic simulators, consisting of live animal and fresh human cadaver models, are considered to be of high-fidelity. Inorganic simulators comprise virtual reality simulators and synthetic bench models. Current evidence suggests that skills acquired through training with simulators, positively transfers to the clinical setting and improves operative outcome. The major challenge for the future revolves around understanding the value of this new technology and developing an educational curriculum that can incorporate surgical simulators.

Is the digitization of laparoscopic movement using accessible alternative technologies possible?

It is widely documented that laparoscopic surgeons require training, and an objective evaluation of the training that they receive. The most advanced evaluation systems integrate the digitization of the movement of laparoscopic tools. A great number of these systems, however, do not permit the use of real tools and their high cost limits their academic impact. Likewise, it is documented that new and accessible systems need to be developed. The aim of this article is to explore the possibility of digitizing the movement of laparoscopic tools in a three-dimensional workspace, using accessible alternative technology. Our proposal uses a commercial Wii video game control in conjunction with a program for determining kinematic variables during the execution of a recognition task.

The Role of Haptics in Medical Training Simulators: A Survey of the State of the Art

This review paper discusses the role of haptics within virtual medical training applications, particularly, where it can be used to aid a practitioner to learn and practice a task. The review summarizes aspects to be considered in the deployment of haptics technologies in medical training. First, both force/torque and tactile feedback hardware solutions that are currently produced commercially and in academia are reviewed, followed by the available haptics-related software and then an in-depth analysis of medical training simulations that include haptic feedback. The review is summarized with scrutiny of emerging technologies and discusses future directions in the field.

How to objectively classify residents based on their psychomotor laparoscopic skills?

In minimally invasive surgery (MIS), a surgeon needs to acquire a certain level of basic psychomotor MIS skills to perform surgery safely. Evaluation of those skills is a major impediment. Although various assessment methods have been introduced, none of them came as a superior. Three aspects of assessing psychomotor MIS skills are discussed here: (i) advantages and disadvantages of currently available assessment methods, (ii) methods to objectively classify residents according to their level of psychomotor skills, and (iii) factors that influence psychomotor MIS skills. Motion analysis has a potential to be the means to deal with assessment of psychomotor skills. Together with classification methods (e.g. linear discriminant analysis), motion analysis provides an aid in deciding whether a resident is ready to move to the next level of training. Presence of factors that influence psychomotor MIS skills results in a high need for standardisation of valid tasks and setups used for the assessment of MIS skills.

The utility of simulation in medical education: what is the evidence?

Medical schools and residencies are currently facing a shift in their teaching paradigm. The increasing amount of medical information and research makes it difficult for medical education to stay current in its curriculum. As patients become increasingly concerned that students and residents are "practicing" on them, clinical medicine is becoming focused more on patient safety and quality than on bedside teaching and education. Educators have faced these challenges by restructuring curricula, developing small-group sessions, and increasing self-directed learning and independent research. Nevertheless, a disconnect still exists between the classroom and the clinical environment. Many students feel that they are inadequately trained in history taking, physical examination, diagnosis, and management. Medical simulation has been proposed as a technique to bridge this educational gap. This article reviews the evidence for the utility of simulation in medical education. We conducted a MEDLINE search of original articles and review articles related to simulation in education with key words such as simulation, mannequin simulator, partial task simulator, graduate medical education, undergraduate medical education, and continuing medical education. Articles, related to undergraduate medical education, graduate medical education, and continuing medical education were used in the review. One hundred thirteen articles were included in this review. Simulation-based training was demonstrated to lead to clinical improvement in 2 areas of simulation research. Residents trained on laparoscopic surgery simulators showed improvement in procedural performance in the operating room. The other study showed that residents trained on simulators were more likely to adhere to the advanced cardiac life support protocol than those who received standard training for cardiac arrest patients. In other areas of medical training, simulation has been demonstrated to lead to improvements in medical knowledge, comfort in procedures, and improvements in performance during retesting in simulated scenarios. Simulation has also been shown to be a reliable tool for assessing learners and for teaching topics such as teamwork and communication. Only a few studies have shown direct improvements in clinical outcomes from the use of simulation for training. Multiple studies have demonstrated the effectiveness of simulation in the teaching of basic science and clinical knowledge, procedural skills, teamwork, and communication as well as assessment at the undergraduate and graduate medical education levels. As simulation becomes increasingly prevalent in medical school and resident education, more studies are needed to see if simulation training improves patient outcomes.

Objective classification of residents based on their psychomotor laparoscopic skills

Background

From the clinical point of view, it is important to recognize residents’ level of expertise with regard to basic psychomotor skills. For that reason, surgeons and surgical organizations (e.g., Acreditation Council for Graduate Medical Education, ACGME) are calling for assessment tools that credential residents as technically competent. Currently, no method is universally accepted or recommended for classifying residents as “experienced,” “intermediates,” or “novices” according to their technical abilities. This study introduces a classification method for recognizing residents’ level of experience in laparoscopic surgery based on psychomotor laparoscopic skills alone.

Methods

For this study, 10 experienced residents (>100 laparoscopic procedures performed), 10 intermediates (10–100 procedures performed), and 11 novices (no experience) performed four tasks in a box trainer. The movements of the laparoscopic instruments were recorded with the TrEndo tracking system and analyzed using six motion analysis parameters (MAPs). The MAPs of all participants were submitted to principal component analysis (PCA), a data reduction technique. The scores of the first principal components were used to perform linear discriminant analysis (LDA), a classification method. Performance of the LDA was examined using a leave-one-out cross-validation.

Results

Of 31 participants, 23 were classified correctly with the proposed method, with 7 categorized as experienced, 7 as intermediates, and 9 as novices.

Conclusions

The proposed method provides a means to classify residents objectively as experienced, intermediate, or novice surgeons according to their basic laparoscopic skills. Due to the simplicity and generalizability of the introduced classification method, it is easy to implement in existing trainers.

Effectiveness of a team participation training course for laparoscopy-assisted gastrectomy

BACKGROUND

Laparoscopy-assisted distal gastrectomy (LADG) for stomach cancer is increasingly performed in Japan and Korea. However, the procedure still is considered to be complicated, and the optimal education system for trainees has not been established to date.

METHODS

The authors organized a 1-day professional training course termed the LADG Basic Lab Course for LADG beginners. The participants were required to apply as a team of two surgeons and two operating nurses. The training course consisted of lectures and a live porcine lab emphasizing use of the ultrasonically activated device and the flexible laparoscope as well as team cooperation. The quality and effectiveness of the course were evaluated 6-10 months (mean, 8.2 +/- 2.2 months) after the course using a survey form sent to a representative surgeon of each institution.

RESULTS

From May 2007 to July 2008, a total of 80 colleagues (47 surgeons and 33 nurses) from 20 different centers in Japan participated in the training course. These surgeons represented 12.4 +/- 6.2 postgraduate years of education and had performed 2.7 +/- 4.9 LADGs before taking the course. In the follow-up evaluation, 12 institutions (60%) completed the survey forms. The mean operation time was reduced for eight respondents (66.7%). The number of LADGs performed per month increased in 50% of the respondents' institutions. The degree of lymph node dissection in LADG was extended for 66.7% of the respondents. The respondents answered that 100% of the first operators showed improvement in skills, as did 59.5% of the scope operators and 59.5% of the nurses.

CONCLUSIONS

The training course was an effective means of introducing LADG to each institution. Training courses emphasizing explanations of key devices and teamwork may be effective for the introduction of advanced laparoscopic surgeries.

Systems for tracking minimally invasive surgical instruments

Minimally invasive surgery (e.g. laparoscopy) requires special surgical skills, which should be objectively assessed. Several studies have shown that motion analysis is a valuable assessment tool of basic surgical skills in laparoscopy. However, to use motion analysis as the assessment tool, it is necessary to track and record the motions of laparoscopic instruments. This article describes the state of the art in research on tracking systems for laparoscopy. It gives an overview on existing systems, on how these systems work, their advantages, and their shortcomings. Although various approaches have been used, none of the tracking systems to date comes out as clearly superior. A great number of systems can be used in training environment only, most systems do not allow the use of real laparoscopic instruments, and only a small number of systems provide force feedback.

Surgical simulator design and development

With the introduction of minimally invasive surgery (MIS), it became necessary to develop training methods to learn skills outside the operating room. Several training simulators have become commercially available, but fundamental research into the requirements for effective and efficient training in MIS is still lacking. Three aspects of developing a training program are investigated here: what should be trained, how it should be trained, and how to assess the results of training. In addition, studies are presented that have investigated the role of force feedback in surgical simulators. Training should be adapted to the level of behavior: skill-based, rule-based, or knowledge-based. These levels can be used to design and structure a training program. Extra motivation for training can be created by assessment. During MIS, force feedback is reduced owing to friction in the laparoscopic instruments and within the trocar. The friction characteristics vary largely among instruments and trocars. When force feedback is incorporated into training, it should include the large variation in force feedback properties as well. Training different levels of behavior requires different training methods. Although force feedback is reduced during MIS, it is needed for tissue manipulation, and therefore force application should be trained as well.

Simulation and surgical training

The aim of this review was to outline current forms of surgical simulation and methods of assessing technical skills using these forms of simulation. To review this subject, a literature search was done using key words 'assessment', 'simulation', 'surgery', 'technical skills' and 'virtual reality'. Simulation in surgery has several forms, inorganic (synthetic & computer) and organic (animal or cadaver). Surgical simulation is a mode of training which is promising and may be effective. Technical errors in the simulated environment do not have clinical consequences and does not have a morbidity or mortality. We must ensure that the competent skills learnt in the simulation environment are translated to the real environment. This can be achieved if the same assessment tools are used in both environments. Surgical training is entering a new era, with increased scrutiny and an evolving work and training environment. We as surgical teachers must ensure that the surgeons of the future are as competent as or better than their predecessors using these new modes of training which we have access to.

Retracting and seeking movements during laparoscopic goal-oriented movements. Is the shortest path length optimal?

Aims

Minimally invasive surgery (MIS) requires a high degree of eye–hand coordination from the surgeon. To facilitate the learning process, objective assessment systems based on analysis of the instruments’ motion are being developed. To investigate the influence of performance on motion characteristics, we examined goal-oriented movements in a box trainer. In general, goal-oriented movements consist of a retracting and a seeking phase, and are, however, not performed via the shortest path length. Therefore, we hypothesized that the shortest path is not an optimal concept in MIS.

Methods

Participants were divided into three groups (experts, residents, and novices). Each participant performed a number of one-hand positioning tasks in a box trainer. Movements of the instrument were recorded with the TrEndo tracking system. The movement from point A to B was divided into two phases: A-M (retracting) and M-B (seeking). Normalized path lengths (given in %) of the two phases were compared.

Results

Thirty eight participants contributed. For the retracting phase, we found no significant difference between experts [median (range) %: 152 (129–178)], residents [164 (126–250)], and novices [168 (136–268)]. In the seeking phase, we find a significant difference (<0.001) between experts [180 (172–247)], residents [201 (163–287)], and novices [290 (244–469)]. Moreover, within each group, a significant difference between retracting and seeking phases was observed.

Conclusions

Goal-oriented movements in MIS can be split into two phases: retracting and seeking. Novices are less effective than experts and residents in the seeking phase. Therefore, the seeking phase is characteristic of performance differences. Furthermore, the retracting phase is essential, because it improves safety by avoiding intermediate tissue contact. Therefore, the shortest path length, as presently used during the assessment of basic MIS skills, may be not a proper concept for analyzing optimal movements and, therefore, needs to be revised.

Mechanical Simulators for Training for Laparoscopic Surgery in Urology

BACKGROUND AND PURPOSE

The introduction of laparoscopic surgery into urology has led to new training concepts differing significantly from previous concepts of training for open surgery. This paper focuses on the type and importance of mechanical simulators in laparoscopic training.

MATERIALS AND METHODS

On the basis of our own studies and experience with the development of various concepts of laparoscopic training, including different modules (i.e., Pelvi-trainer, animal models, clinical mentoring) since 1991, we reviewed the current literature concerning all types of simulators. We focused on training for laparoscopic ablative and reconstructive surgery using mechanical simulators.

RESULTS

The principle of a mechanical simulator (i.e., a box with the possibility of trocar insertion) has not changed during the last decade. However, the types of Pelvi-trainers and the models used inside have been improved significantly. According to the task of the simulator, various sophisticated models have been developed, including standardized phantoms, animal organs, and even perfused segments of porcine organs. For laparoscopic suturing, various step-by-step training concepts have been presented. These can be used for determination of the ability of a physician with an interest in laparoscopic surgery, but also to classify the training status of a laparosopic surgeon.

CONCLUSIONS

Training in laparoscopic surgery has become an important topic, not only in learning a procedure, but also in maintaining skills and preparing for the management of complications. For these purposes, mechanical simulators will definitely play an important role in the future.