Human cadavers have re-emerged in surgical simulations for military, civilian and medical school training. Anthony Bitar, Ezekiel Kapusciak and Dr. Joss Fernandez describe the use of perfused cadavers for a more ‘realistic training experience’.
Training, of any magnitude, should be geared at preparing the trainee in a manner that produces the best results. A mainstay of effective training in the healthcare industry is simulating real life scenarios. “Simulation offers an immersive, realistic way of learning technical skills.” (Agha and Fowler, 2015) Some universities now own full functioning simulation hospitals. The idea behind this is simple; the closer to real life a simulation can be made the better prepared a trainee will be when it counts. The diversity of simulation training is vast. New technologies are coming out with great frequency. The result is many different specialized simulators but without one that meets all the wide-ranging needs of today’s trainees. With all these different types of simulators it is estimated the average simulation center will spend between $200,000 to $1.2 million in startup cost with $15,000 annual expenditures which excludes personnel costs. Despite these great monetary outlays many of these simulation centers are under-utilized for the simple fact that they lack realism.
In response, companies have leveraged the re-emergence of human cadavers in surgical simulations. The Dynamic cadaver makes use of new techniques and developments in cadaver handling, perfusion and ventilation to provide a cadaver with a reconstituted circulation and respirations. Dynamic cadavers have been utilized by military personnel, paramedics, physicians and researchers in different degrees all showing the versatility of this new simulation training.
Currently four broad categories for surgical simulations exist.
- Computer simulations are effective for the replication of video assisted surgical procedures but lack the tactile feedback and anatomical realism.
- Mannequins often packed with technology form a great base for fundamental learning but lack realism.
- Live tissue training has the benefit of realism but often offers anatomical variations that deter from the learning. Furthermore, the use of animals carries with it ethical and cost issues. There has been a push from the public to move away from live animals. Currently, the United States Congress is reviewing HR 1243 and S 498 Battlefield Excellence through Superior Training (BEST) Practices Bill banning the use of live animals in military training.
- The modern dynamic cadavers provide multiple uses with many different techniques with excellent realism. The use of cadavers though is limited by cost and storage.
Skills that have been taught numerous different ways in the past are now finding great success with the dynamic cadaver. Take lifesaving tourniquets for example. Although mannequins may play a role in initial training, there is no substitute for a perfused cadaver to evaluate the effectiveness of the trainee’s technique. The presence of a pulse in the perfused cadaver is a unique feature that adds to the immersion of training. By having a pulsing model with the exact anatomy of a live human the training experience is as life like as possible. This situation can be altered in several ways with a perfused cadaver. The most basic of which is simply practicing a tourniquet on an intact cadaver. This allows the user a chance to familiarize themselves with the equipment and proper techniques with repetition. A perfused cadaver can maintain a pulse for hours with an unlimited supply of artificial blood, allowing first responders and military members the chance to master basic tourniquet skills.
Perfused cadavers have the capability to bleed similarly to that of humans. This allows users to practice tourniquet placement on an actual bleeding model that responds in a fashion analogous to that of real life. These labs can be altered in many ways to provide a varying range of experiences, from car crashes to mass casualty situations. Perfused cadavers offer a training experience that brings the user closer to real life.
The benefits to using a dynamic cadaver don’t stop with first responders and tourniquets. Many hospitals and medical schools have started using perfused cadavers for training physicians. In this aspect, perfused cadavers again show their versatility. From placement of central venous catheters to endoscopic surgery to microvascular procedures; perfused cadavers have shown great success as training models.
A research team out of the San Antonio Military Medical Center, department of surgery, recently published a paper speaking to the benefits of perfused cadavers in catheterization training. Eighty-seven physicians of different specialties took part in the trials. All of them received a didactic lecture followed by a simulation using a commercially available simulator and then attempted catheterization on a perfused cadaver. The participants were then surveyed.
“Results of the survey demonstrated that 91% of the participating physicians found the perfused cadaveric model to be a true simulation of conditions that exist in live patients, and 98% reported that the use of this model promoted acquisition of technical skills.” (Varga, Smith, Minneti, Carey, Zakaluzny, Noguchi, Demetriades, and Talving, 2015) This example demonstrates the usefulness of perfused cadavers as a training model in a controlled scenario. Perfused cadavers have also been used to simulate catastrophes to prepare trainees for the unexpected.
Medical education personnel, residents and researchers out of Keck School of Medicine of the University of Southern California, department of neurosurgery, developed a lab in which residents and junior faculty could practice responding to arterial injuries during endoscopic endonasal surgeries. All of the trainees from this lab reported a realistic experience that was enhanced by the perfusion of the cadaver. The team there concluded, “The addition of an arterial perfusion system to fresh tissue cadavers is among the most realistic training models available. This enables the simulation of rare intraoperative scenarios such as ICA injury.” (Pharm, Kale, Marquez, Winer, Lee, Harris, Minnetti, Carey, Giannotta and Zada, 2014).
Another research team out of Keck School of Medicine of the USC, department of plastic surgery, tested a multitude of different surgeries on perfused cadavers in an attempt to determine how closely simulated perfused cadavers surgeries mimicked real life. They attempted thirty-eight procedures with varying degrees of difficulty. All of which, including the most complex microsurgical flap transfer, were reported successful.
The perfused cadaver model has been making an impact in education and training. “We anticipate utilization of this model prior to entering the operating room will enhance surgical ability and offer a valuable resource in plastic surgical education.” (Carey, Rommer, Sheckter, Minneti, Talving, Wong, Garner and Urata, 2014) The benefits of perfused cadavers have been demonstrated for educational purposes but that is not their only purpose.
Perfused cadavers offer a unique opportunity for researchers and product developers to test theories and try products on a model that very nearly mimics real life. Not only are users able to practice tourniquets using a perfused model but users are also able to test new products.
The Junctional Emergency Treatment Tool (JETT) is a novel device with the goal of reducing preventable death on the battlefield from groin bleeds. This research would have been difficult to complete without the use of a perfused cadaver model. The JETT was tested against the gold standard femoral artery tourniquet tool and was found to be as effective at stopping blood flow with a much more rapid application time. Having a perfused cadaver model to test this product allowed for a realistic representation of this new product. Many other companies used perfused cadavers when developing products. From tourniquets to boviee tools, perfused cadavers have offered a distinct advantage in research and development. There is even research being conducted currently to enhance the perfused cadaver experience.
Typically these cadavers are perfused using a synthetic blood. While having a pulse and moving blood there are still some components of real life that have not been replicated, one of which is clotting. New research in this area hopes to provide advancement to the perfused cadaver model. Soon there may be perfused cadavers that not only have a pulsatile blood flow but also can offer the same clotting dynamics as a living individual. This novel idea may increase the usefulness and versatility of perfused cadavers, opening up more training experiences and newer research opportunities.
While all the aforementioned benefits grant valuable experience and information to trainees and researchers the benefits go far beyond. Greater expectations along with greater training modules will lead to better outcomes for patients. New products being developed with the aid of perfused cadavers will save lives and institute a new standard of care. While the average citizen may never be a part of a perfused cadaver learning experience they may gain benefit from them.
Reducing Medical Errors
Within the medical community there has been a huge push to reduce medical errors. Simulations and training experiences can aid in this pursuit of perfection. In surgery training, a lot is changing. Historically, surgical residents have gained a majority, if not all, of their training from experience. Unfortunately, limitations on training hours and changes in practice partners have hampered the surgical training experience. The Society of Vascular Surgery estimates that by 2020 fellows training in vascular surgery will have been exposed to only, on average, five aortic surgeries. This is a far cry from the 30-50 aortic surgeries needed to be credentialed. The use of simulations, including perfused cadaver models, has been pushing surgical training in a different direction. This new school of thought is based more on capability. Dr. Agha from Pinderfields Hospital, department of plastic surgery, spoke to this fact stating, “surgery has moved away from its traditional apprenticeship model and toward a competency based one.” (Agha and Fowler, 2015)[ibid] Not only have simulations been used as training techniques they can also be a means of assessing health care providers abilities. “Simulation can be a standardized and safe method for training and assessing surgeons.” (Agha and Fowler, 2015)[ibid] These changes will lead to better patient care and improved outcomes.
In conclusion, studies have shown the effectiveness of perfused cadavers and its impact on surgical training by providing a real life experience that current institutions are starting to utilize. Data shows and agrees that perfused cadavers are an alternative to expensive surgical simulating tools and mannequins, and allows fellows to gain the necessary experience to be competent and credentialed. Additionally, having the ability to manipulate situations and recreate different scenarios during training, whether it be practicing with a tourniquet or any other surgical tools, allows trainees to identify their weaknesses and improve their skills. Finally, perfused cadavers are a relatively new technology that has only begun to be utilized and hold great potential for the future of surgical training and healthcare education.
About the Authors
Anthony Bitar and Ezekiel Kapusciak are medical students at University of Missouri School of Medicine. They both have tremendous experience working with perfused cadavers. During their school year they travel to perform dynamic cadavers labs and have worked with Maximum Fidelity Surgical Simulations developing new products and new technologies to the field of surgery simulations. They have conducted research in bone regeneration utilizing bioactive glass scaffolds as well as on patient outcomes of colorectal cancer resections.
Dr. Joss Fernandez is a leading cardiothoracic surgeon. Through his many years of surgery he has gained experience that allowed him to build Maximum Fidelity Surgical Simulations from the ground up. He has been a part of revolutionizing the realm of perfused cadavers and holds several patents and publications regarding dynamic cadavers and is a leader in this field.
- Agha, Riaz A., and Alexander J. Fowler. 2015. "The Role And Validity Of Surgical Simulation". International Surgery 100 (2): 350-357. International College of Surgeons. doi:10.9738/intsurg-d-14-00004.1.
- Varga S, et al. 2018. "Central Venous Catheterization Using A Perfused Human Cadaveric Model: Application To Surgical Education. - Pubmed - NCBI ". Ncbi.Nlm.Nih. Gov. Accessed August 31 2018. https://www.ncbi.nlm.nih.gov/pubmed/25129205.
- Pham, Martin, Aydemir Kale, Yvette Marquez, Jesse Winer, Brian Lee, Brianna Harris, Michael Minnetti, Joseph Carey, Steven Giannotta, and Gabriel Zada. 2014. "A Perfusion-Based Human Cadaveric Model For Management Of Carotid Artery Injury During Endoscopic Endonasal Skull Base Surgery". Journal Of Neurological Surgery Part B: Skull Base 75 (05): 309-313. Georg Thieme Verlag KG. doi:10.1055/s-0034-1372470.
- Carey, Joseph N., Elizabeth Rommer, Clifford Sheckter, Michael Minneti, Peep Talving, Alex K. Wong, Warren Garner, and Mark M. Urata. 2014. "Simulation Of Plastic Surgery And Microvascular Procedures Using Perfused Fresh Human Cadavers". Journal Of Plastic, Reconstructive & Aesthetic Surgery 67 (2): e42-e48. Elsevier BV. doi:10.1016/j.bjps.2013.09.026.
Originally published in Issue 4, 2018 of MT Magazine.