Construct validity of fresh frozen human cadaver as a training model in minimal access surgery

Collating evidence to support the validation of a simulated laparotomy incision and closure-training model

BACKGROUND

It is essential to evaluate the functionality of surgical simulation models, in order to determine whether they perform as intended. In this study, we assessed the use of a simulated laparotomy incision and closure-training model by collating validity evidence to determine its utility as well as pre and post-test interval data.

METHOD

This was a quantitative study design, informed by Messick's unified validity framework. In total, 93 participants (surgical trainees ​= ​80, experts ​= ​13) participated in this study. Evaluation of content validity and the models' relationships with other variables was conducted, along with a pre and post-test confidence assessment.

RESULTS

The model was deemed realistic and useful as a teaching tool, providing strong content validity evidence. In assessment of relationships with other variables, the expert group out-performed the novice group conclusively. Pre and post-test evaluation reported a statistically significant increase in confidence levels.

CONCLUSION

We present strong validity evidence of a novel laparotomy incision and closure simulation-training model.

Psychological Consequences of the Delay in the Silent Mentor Programme During the COVID-19 Pandemic: Perspectives From Family Members of Silent Mentors

The COVID-19 pandemic has put a hold on the Silent Mentor Programme (SMP); this pause has not only caused unprecedented challenges for the delivery of medical education but has forced changes in the programme ceremony sessions. We aimed to describe the psychological impact and experiences of family members of silent mentors during the COVID-19 pandemic using qualitative interviews. Many expressed feelings of remorse and unrest about the unprecedented delay of the SMP. The delay increased negative emotions particularly among some elderly family members; however, there was no prominent negative effect on their functional health and well-being. Several participants relayed the belief that the soul cannot rest until the body receives a proper burial while some worried about the deterioration of the physical condition of the mentors. In conclusion, findings provide insights into the importance of not overlooking the mental health implications of delaying the SMP in future outbreaks or crises.

Current and potential use of fresh frozen cadaver in surgical training and anatomical education

As surgical procedures continue to be more complex, the need for more effective training in anatomy has increased. The study of anatomy plays a significant role in the understanding of the human body as well as in basic and advanced clinical training. Among the different cadaver models, fresh frozen cadavers (FFCs) are known for their realistic tissue quality. The purpose of this article was to review and summarize the preparation procedures for and reported cases involving FFCs. PubMed, Scopus, Medline, and Web of Science were searched for relevant studies. The preparation procedures were divided into five steps: washing, irrigation, freezing, defrosting, and arterial infusion. Not all steps were reported to be mandatory, but omitting one or more could result in a loss of quality. FFCs were reported to be used for various purposes: undergraduate education, general surgery training, vascular surgery training, minimal access surgery (laparoscopic surgery) training, and microsurgery training. In all categories, expert opinions and statistical analyses indicated successful outcomes. The reasons for high satisfaction with FFCs included realistic texture, capability of reenacting actual operations, and accuracy of anatomical locations. The results also revealed the importance and advantages of the dissection courses in surgical training. Since the direct comparison between cadaver models is insufficient, future studies regarding this topic are deemed necessary. In addition, it would be advantageous to develop methods to improve FFC quality, or ideas to optimize this model for certain purposes.

A review of simulation training and new 3D computer-generated synthetic organs for robotic surgery education

We conducted a comprehensive review of surgical simulation models used in robotic surgery education. We present an assessment of the validity and cost-effectiveness of virtual and augmented reality simulation, animal, cadaver and synthetic organ models. Face, content, construct, concurrent and predictive validity criteria were applied to each simulation model. There are six major commercial simulation machines available for robot-assisted surgery. The validity of virtual reality (VR) simulation curricula for psychomotor assessment and skill acquisition for the early phase of robotic surgery training has been demonstrated. The widespread adoption of VR simulation has been limited by the high cost of these machines. Live animal and cadavers have been the accepted standard for robotic surgical simulation since it began in the early 2000s. Our review found that there is a lack of evidence in the literature to support the use of animal and cadaver for robotic surgery training. The effectiveness of these models as a training tool is limited by logistical, ethical, financial and infection control issues. The latest evolution in synthetic organ model training for robotic surgery has been driven by new 3D-printing technology. Validated and cost-effective high-fidelity procedural models exist for robotic surgery training in urology. The development of synthetic models for the other specialties is not as mature. Expansion into multiple surgical disciplines and the widespread adoption of synthetic organ models for robotic simulation training will require the ability to engineer scalability for mass production. This would enable a transition in robotic surgical education where digital and synthetic organ models could be used in place of live animals and cadaver training to achieve robotic surgery competency.

Three-dimensional ultrasound for knee osteophyte depiction: a comparative study to computed tomography

Purpose

Osteophytes are common radiographic markers of osteoarthritis. However, they are not accurately depicted using conventional imaging, thus hampering surgical interventions that rely on pre-operative images. Studies have shown that ultrasound (US) is promising at detecting osteophytes and monitoring the progression of osteoarthritis. Furthermore, three-dimensional (3D) ultrasound reconstructions may offer a means to quantify osteophytes. The purpose of this study was to compare the accuracy of osteophyte depiction in the knee joint between 3D US and conventional computed tomography (CT).

Methods

Eleven human cadaveric knees were pre-screened for the presence of osteophytes. Three osteoarthritic knees were selected, and then, 3D US and CT images were obtained, segmented, and digitally reconstructed in 3D. After dissection, high-resolution structured light scanner (SLS) images of the joint surfaces were obtained. Surface matching and root mean square (RMS) error analyses of surface distances were performed to assess the accuracy of each modality in capturing osteophytes. The RMS errors were compared between 3D US, CT and SLS models.

Results

Average RMS error comparisons for 3D US versus SLS and CT versus SLS models were 0.87 mm ± 0.33 mm (average ± standard deviation) and 0.95 mm ± 0.32 mm, respectively. No statistical difference was found between 3D US and CT. Comparative observations of imaging modalities suggested that 3D US better depicted osteophytes with cartilage and fibrocartilage tissue characteristics compared to CT.

Conclusion

Using 3D US can improve the depiction of osteophytes with a cartilaginous portion compared to CT. It can also provide useful information about the presence and extent of osteophytes. Whilst algorithm improvements for automatic segmentation and registration of US are needed to provide a more robust investigation of osteophyte depiction accuracy, this investigation puts forward the potential application for 3D US in routine diagnostic evaluations and pre-operative planning of osteoarthritis.

Positioning accuracy assessment of minimally invasive percutaneous injection techniques for the treatment of temporomandibular disorders

OBJECTIVE

The aim of the present study was to evaluate the accuracy of an extraoral CBCT-planned 3D-printed surgical guide aimed to percutaneous injection of substances into the temporomandibular joint (TMJ) and the lateral pterygoid muscle (LPM).

METHODS

Nine human cadaver heads were used. Pre-planning CBCT and facial scans were obtained and three percutaneous injection sites were planned: one for the lower compartment of the TMJ and two for the LPM. A digital surgical guide was then designed with small titanium sleeves and printed by a 3D printer. After the injections, new CBCT scans with the needles in place were obtained in order to assess the accuracy of the procedure in relation to the virtual planning.

RESULTS

The mean values for angle deviation were very low (range 1.13^o-4.08^o), the same happening for the mean difference in the length reached (range 1.82-2.64 mm), as well as for the mean difference in the needle tip dislocation (range 0.94-2.03 mm).

CONCLUSION

The guide seems to be a reliable tool for accurate percutaneous injection of drugs into the inferior compartment of the TMJ and the LPM. Further studies are necessary to test the efficacy and validate the method in an in vivo study.

Depth and Location of Sacral Suture Placement During Cadaveric Simulation of Open Sacrocolpopexy

OBJECTIVES

To evaluate the location and depth of placement of sacral sutures in a cadaveric sacrocolpopexy model.

MATERIALS AND METHODS

Following a 1-hour instructional session, trainees performed an open sacrocolpopexy on unembalmed cadavers under guidance by a Female Pelvic Medicine & Reconstructive Surgery board-certified surgeon. At completion of the session, the presacral tissues were dissected and the location and depth of each sacral suture was identified.

RESULTS

A total of 19 sutures were placed by 9 trainees into 8 cadavers. The majority of sutures (14/19, 74%) were placed between L5 and S1. Three sutures (16%) were placed at L5 and 2 (11%) were placed at the S1 vertebral body. The mean depth of the anterior longitudinal ligament (ALL) was 1.4 mm. When assessing depth of suture placement, 13 of 19 (68%) were placed into the ALL without penetrating the disc space. Two sutures (11%) were placed in the tissues superficial to the ALL and 4 (22%) were placed deep to the ALL into the periosteum or disc.

CONCLUSION

This study of cadaveric simulation of open sacrocolpopexy finds that location of sacral suture placement is most commonly at the level of the L5-S1 disc space and that placement of sutures into the underlying disc occurs about 1 in 5 times.

Surgical training in video-assisted neck surgery-based thyroidectomy using fresh frozen human cadavers

Endoscopic surgery has been introduced in various surgical fields. Endoscopic surgery requires different skills from open surgery due to the restricted surgical field and difficulty in identifying anatomical structures from certain viewpoints. Therefore, surgeons need to undergo sufficient surgical training before performing such surgery in the clinical setting. We examined the utility of fresh frozen human cadavers for surgical training aimed at introducing video-assisted neck surgery (VANS) at our department. First, we performed surgical training using fresh human cadavers four times. Next, we performed hemi-thyroidectomy with VANS in 5 clinical patients. After the cadaver training and the actual surgery, the surgeons evaluated each step of the surgical procedure using a 3-point scale. In the cadaver training, the scores for steps : creation of a subcutaneous tunnel and lifting up the skin flap and pre-thyroid muscles were higher than other steps. And a tracheal injury occurred as a complication. However, we were able to recognize anatomical structures under the endoscopic view. And it was also useful for confirming the role of surgical staff and simulating the placement of surgical equipment. Surgical training using fresh frozen human cadavers was effective at introducing a new surgical method. J. Med. Invest. 66 : 293-296, August, 2019.

Lightly Embalmed Cadavers in Sonography Education: A Novel Approach to Improving Students’ Perceived Competence in Renal Biopsy Procedures

Objective:

To determine if a simulation lab using lightly embalmed cadavers would improve diagnostic medical sonography (DMS) students’ perceived competence in ultrasound-guided native renal biopsy examinations.

Methods:

Subjects included DMS students (n = 49) enrolled in academic years 2012 to 2018. Each DMS student performed a native renal biopsy with a nephrology fellow. Skills practiced included machine setup, inferior renal pole localization, biopsy guide preparation, needle visualization, and communication skills. Pre- and postlab surveys assessed DMS students’ perceived competence.

Results:

Prelab, 12% (n = 6) of students felt competent to assist in the procedure. Postlab, 61% (n = 35) of students felt competent, a statistically significant ( P < .001) change. All students viewed the lab as a valuable experience. Hands-on experience (53%), student/physician collaboration (33%), and low-stress environment (13%) were reported themes. Additional resources (50%) and scheduling (22%) were areas for improvement.

Conclusion:

A renal biopsy simulation lab using lightly embalmed cadavers is an effective method to improve DMS students’ perceived competence in this procedure.

Simulation platforms to assess laparoscopic suturing skills: a scoping review

BACKGROUND

Laparoscopic suturing (LS) has become a common technique used in a variety of advanced laparoscopic procedures. However, LS is a challenging skill to master, and many trainees may not be competent in performing LS at the end of their training. The purpose of this review is to identify simulation platforms available for assessment of LS skills, and determine the characteristics of the platforms and the LS skills that are targeted.

METHODS

A scoping review was conducted between January 1997 and October 2018 for full-text articles. The search was done in various databases. Only articles written in English or French were included. Additional studies were identified through reference lists. The search terms included "laparoscopic suturing" and "clinical competence."

RESULTS

Sixty-two studies were selected. The majority of the simulation platforms were box trainers with inanimate tissue, and targeted basic suturing and intracorporeal knot-tying techniques. Most of the validation came from internal structure (rater reliability) and relationship to other variables (compare training levels/case experience, and various metrics). Consequences were not addressed in any of the studies.

CONCLUSION

We identified many types of simulation platforms that were used for assessing LS skills, with most being for assessment of basic skills. Platforms assessing the competence of trainees for advanced LS skills were limited. Therefore, future research should focus on development of LS tasks that better reflect the needs of the trainees.

BODIES R US: Ethical Views on the Commercialization of the Dead in Medical Education and Research

With the ongoing and expanding use of willed bodies in medical education and research, there has been a concomitant rise in the need for willed bodies and an increase in the means of supplying these bodies. A relatively recent development to enlarge this supply has been the growth of for- profit willed body companies ("body brokers") in the United States. These companies advertise for donors, cover all cremation and other fees for the donor, distribute the bodies or body parts nationally and internationally, and charge their users for access to the body or body parts. In doing so, they generate substantial profits. This review examines the historical development of willed body programs, the legal and economic aspects of willed body programs, and then provides an ethical framework for the use of willed bodies. The ethical principles described include detailed informed consent from the donors, comprehensive and transparent information about the process from the body donation organizations, and societal input on the proper and legal handling of willed bodies. Based on the ethical principles outlined, it is recommended that there be no commercialization or commodification of willed bodies, and that programs that use willed bodies should not generate profit.

Evaluating the Construct Validity of a Pulsatile Fresh Frozen Human Cadaver Circulation Model for Endovascular Training

BACKGROUND

We recently described a pulsatile fresh frozen human cadaver model (PHCM) for training endovascular practitioners. This present study aims to assess the construct validity of PHCM; its ability to differentiate between participants of varying expertise.

METHODS

Twenty-three participants with varying endovascular experience (12 novice, 4 intermediate, and 7 expert) were recruited. Each attempted catheterization of the left renal artery on PHCM within 10 min under exam conditions. Performances were video recorded and scored using a validated scoring tool by 2 independent endovascular experts, blinded to performer status. Each participant was given a task-specific checklist score (TSC), global rating score (GRS), and overall procedure score (OPS). Finally, examiners were asked whether they would be happy to supervise the participant in theater, with each participant graded as "fail", "borderline," or "pass".

RESULTS

All expert and intermediate participants completed the index procedure within the allotted 10 min; however, only one of the 12 novice participants achieved this (P < 0.0005). Endovascular novices had significantly lower TSC, GRS, and OPS than both intermediate participants and endovascular experts. There were no significant differences in TSC, GRS, or OPS between intermediate participants and endovascular experts. When participants were graded as "fail", "borderline," or "pass," there were significant differences between groups (P = 0.001). All of the intermediate and expert participants received a pass. Out of the 12 novice participants, 2 received a pass, 6 received a borderline, and 4 were failed.

CONCLUSIONS

The PHCM demonstrates construct validity. Further work is required to determine its educational impact in endovascular training.

Human cadavers to evaluate prototypes of minimally invasive surgical instruments: A feasibility study

BACKGROUND

New technology should be extensively tested before it is tried on patients. Unfortunately representative models are lacking. In theory, fresh frozen human cadavers are excellent models.

OBJECTIVE

To identify strengths and weaknesses of fresh frozen human cadavers as research models for new technology prior to implementation in gynecological surgery.

METHODS

During pre-clinical validation studies regarding the MobiSep uterine manipulator, test procedures were performed on fresh frozen cadavers. Both the experimental setup as the performance of the prototype were assessed.

RESULTS

Five tests including six human cadavers were performed. Major changes were made to the MobiSep prototype design. The cadavers of two tests closely resembled surgical experiences as found in live patients. The anatomy of 4 of the 6 cadavers was not fully representative due to atrophy of the internal genitalia caused by age and due to the presence of pathology such extensive tumorous tissue.

CONCLUSION

The cadaver tests provided vital information regarding design and functionality, that failed to emerge during the in-vitro testing. However, experiments are subject to anatomical uncertainties or restrictions. Consequently, the suitability of a cadaver should be carefully assessed before it is used for testing new technology.

ENDOSCOPIC INTERLAMINAR DISCECTOMY. USE OF SWINE CADAVERS AS A TRAINING MODEL

ABSTRACT Objective: To analyze the possibility of using cadavers of pigs for training in endoscopic interlaminar discectomy. Methods: Five young pigs were used. The necessary instruments and equipment were used, and the endoscopic transforaminal and interlaminar percutaneous approach was performed at the L7-S1 level. A specialist surgeon performed the procedure. The points of entry, needle angulation, and subjective technical difficulties indicated by the surgeon were analyzed. Results: The mean weight of pigs was 42.2 kg. The posterolateral (transforaminal) entry point was, on average, 6.28 cm from the midline at an angulation of 32.8°. The posterior (interlaminar) entry point was on average 1.82 cm. Full-endoscopic interlaminar discectomy was possible in all animals of the sample. The structures described in the literature were visible endoscopically in 100% of the models. Conclusions: The demonstrated benefits and increased indications of endoscopic lumbar surgery created the need to establish safer and more efficient training processes. The authors raise the possibility of using experimental models to develop technical skills in endoscopy via interlaminar approach. The use of teaching tools such as animal models constitutes a new learning technique and give more confidence to surgeons. The use of cadavers of pigs, obtained according to ethics, avoids the use of human cadavers, and minimizes the development of the learning curve on patients.

A novel technique to practice using a high-speed burr for spinal anterior cervical discectomy and fusion

BACKGROUND

Anterior cervical discectomy and fusion has been a successful procedure in terms of patient satisfaction in the management of cervical myelopathy and radiculopathy. The procedure involves an anterior approach to the cervical vertebral column and decompression of the neural elements.

AIM

A key part of the procedure is the removal of the posterior osteophyte. This is usually performed using a high-speed burr. In inexperienced hands, this part of the procedure can be a challenging one.

MATERIALS

Egg, egg cup, zinc oxide tape and high-speed burr.

CONCLUSION

We describe a simple and cost effective method of practicing this manoeuver, enabling the trainee to gain sufficient confidence in handling the tool around delicate tissues.

Simulated training in colonoscopic stenting of colonic strictures: validation of a cadaver model

AIM

There are currently no available simulation models for training in colonoscopic stent deployment. The aim of this study was to validate a cadaver model for simulation training in colonoscopy with stent deployment for colonic strictures.

METHOD

This was a prospective study enrolling surgeons at a single institution. Participants performed colonoscopic stenting on a cadaver model. Their performance was assessed by two independent observers. Measurements were performed for quantitative analysis (time to identify stenosis, time for deployment, accuracy) and a weighted score was devised for assessment. The Mann-Whitney U-test and Student's t-test were used for nonparametric and parametric data, respectively. Cohen's kappa coefficient was used for reliability.

RESULTS

Twenty participants performed a colonoscopy with deployment of a self-expandable metallic stent in two cadavers (groups A and B) with 20 strictures overall. The median time was 206 s. The model was able to differentiate between experts and novices (P = 0. 013). The results showed a good consensus estimate of reliability, with kappa = 0.571 (P < 0.0001).

CONCLUSION

The cadaver model described in this study has content, construct and concurrent validity for simulation training in colonoscopic deployment of self-expandable stents for colonic strictures. Further studies are needed to evaluate the predictive validity of this model in terms of skill transfer to clinical practice.

Comparison of modified Thiel embalming and ethanol-glycerin fixation in an anatomy environment: Potentials and limitations of two complementary techniques

Thiel-fixed specimens have outstandingly lifelike visual and haptic properties. However, the original Thiel method is expensive and requires an elaborate setup. It is therefore of principal interest to modify the Thiel method in order to make it available to a broader user group. A modified Thiel embalming method will be described in detail and compared to ethanol-glycerin fixation with the help of illustrative examples. The visual properties, haptic properties, the usability for performing histological investigations, costs and potential health aspects will be considered. Tissues fixed with the modified Thiel technique gave results similar to the original method, providing more realistic visual and haptic properties than ethanol-glycerin embalming. However, Thiel fixation is significantly more expensive and requires more precautions to minimize potential health hazards than ethanol-glycerin-fixed tissues. In contrast to ethanol-glycerin-fixed specimens, the Thiel-fixed specimens are not suitable for histological investigations. Both modes of fixation are inappropriate for biomechanical testing. Modified Thiel embalming simplifies the availability of body donors with lifelike properties and has cost-saving advantages to the original technique. Thiel-embalmed body donors are ideally suited for clinical workshops but have restrictions for student dissection courses in facilities with limited storage space, air circulation or technical staff. Vice versa, ethanol-glycerin-fixed body donors are well suited for student dissection courses in such an environment but are limited in their use for clinical workshops. Modified Thiel embalming therefore ideally complements ethanol-glycerin fixation in order to provide customized solutions for clinical workshops and student dissection courses in a wide range of applications.

From "silent teachers" to models

In this essay Roos Eisma and Tracey Wilkinson describe how the Thiel technique has expanded the range of applications in which embalmed human cadavers can be used.

For decades, embalmed cadavers have played an important role in teaching anatomy to the scientists and doctors of the future. Most anatomy departments use a traditional formaldehyde-based embalming method, but formalin embalming makes the bodies very rigid, which limits their usefulness for procedures other than dissection. A more recent embalming method developed by W. Thiel has allowed these “silent teachers” to take on a further role in applied anatomy research and teaching: to act as models for surgical training and medical research.

Improved nondominant hand performance on a laparoscopic virtual reality simulator after playing the Nintendo Wii

BACKGROUND

Video games have been shown to improve eye-hand coordination, spatial visualization, manual dexterity, and rapid mental processing, which are important in the acquisition of laparoscopic skills. This study investigated the relationship between playing Nintendo(®) Wii™ and virtual reality (VR) laparoscopic surgery simulator performance. We hypothesized that playing the Wii would improve surgical skills performance on a VR laparoscopic simulator and hoped to elucidate which tasks, in particular, would be most beneficial for nondominant hand training.

METHODS

This was a single-blinded, randomized, prospective study conducted with 23 student volunteers. VR laparoscopic skills were assessed at baseline on a Simbionix LapMentor™ Surgical Simulator (Simbionix Ltd., Israel) and after the gaming period of 2 weeks. Simulator performance metrics were compared between groups using nonparametric statistics and an alpha of 0.05.

RESULTS

Compared with the control group, the Wii-playing group demonstrated greater improvement of six measures, including accuracy on the eye-hand coordination task (p = 0.04), faster completion time (p = 0.04), decreased number of left-handed movements (p = 0.03), decreased left handed total path length (p = 0.03), decreased total number of grasping attempts (p = 0.04), and improved left-handed economy of movement (p = 0.05) for the bimanual clipping and grasping task. When comparing the number of measures improved upon by the Wii-playing group and the control group for all three tasks, the Wii-playing group consistently outperformed the control group in 18 measures compared with the control group's improvement in 6.

CONCLUSIONS

This study further characterizes the association between video game playing and surgical performance. Improvements following the intervention were made in the most basic of surgical skills, most notably with the nondominant hand, suggesting that short-term playing of the Wii could improve bimanual dexterity and expedite the acquisition of basic surgical skills.

Basic laparoscopic skills training using fresh frozen cadaver: a randomized controlled trial

BACKGROUND

The purpose of this study was to determine whether training on fresh cadavers improves the laparoscopic skills performance of novices.

METHODS

Junior surgical trainees, novices (<3 laparoscopic procedure performed) in laparoscopic surgery, were randomized into control (group A) and practice groups (group B). Group B performed 10 repetitions of a set of structured laparoscopic tasks on fresh frozen cadavers (FFCs) improvised from fundamentals of laparoscopic skills technical curriculum. Performance on cadavers was scored using a validated, objective Global Operative Assessment of Laparoscopic Skills scale. The baseline technical ability of the 2 groups and any transfer of skills from FFCs was measured using a full procedural laparoscopic cholecystectomy task on a virtual reality simulator before and after practice on FFCs, respectively. Nonparametric tests were used for analysis of the results.

RESULTS

Twenty candidates were randomized; 1 withdrew before the study commenced, and 19 were analyzed (group A, n = 9; group B; n = 10). Four of 5 tasks (nondominant to dominant hand transfer, simulated appendectomy, intracorporeal, and extracorporeal knot tying) on FFCs showed significant improvement on learning curve analysis. After training, significant improvement was shown for safety of cautery (P = .040) and the left arm path length (P = .047) on the virtual reality simulator by the practice group.

CONCLUSIONS

Training on FFCs significantly improves basic laparoscopic skills and can improve full procedural performance.