New Methods for Microsurgical Training
Animal laboratories are quickly being replaced in many areas of medical training. The vast majority of medical schools in the United States have abandoned live animal labs in favor of computer-based exercises, and high-tech simulators have debuted in teaching labs for emergency trauma procedures, laparoscopy, and, now, for microsurgical training—all with excellent results.
Microsurgery involves the repairing of tiny vessels and nerves under an operating microscope. Microvascular surgery permits anastomosis (surgical connection) of peripheral blood vessels, and microneural surgery allows the surgeon to repair or replace severed and damaged peripheral nerves. Using these techniques, skilled surgeons can correct malformations of the hand and perform other reconstructive surgeries, fix delicate urological conditions, and even reattach severed digits.
Until recently, standard microsurgery training involved practicing on live, anesthetized rats. But modern simulators are more convenient and less expensive. Without having to rely on animal facilities, instructors and students can practice on simulators again and again until the highest level of proficiency is reached. Most importantly, simulators eliminate ethical complications that often arise, as many surgeons oppose practicing their skills on live animals.
One such simulator, PracticeRat, was developed at Triangle Research and Development Corporation, APM, Inc., and the North Carolina State University College of Veterinary Medicine. The model uses polyethelyne tubes (with a one-millimeter diameter) to simulate an artery, vein, or a nerve. The vessels are covered with a stretchy “membrane” to simulate the outer covering of the vessel, or adventitia, and can be pulled away and cut with microscissors, just like living tissue. Pumps provide simulated venous and arterial circulation in opposite directions, allowing patency and quality of anastomoses to be assessed.
Other prosthetic microsurgical training models using various materials have been tested, and all share the advantages of low cost, minimal maintenance, convenient portability, and elimination of ethical concerns.
Perhaps most promising of all are high-tech virtual reality microsurgical models. Once just a hope for the future, several such models are already being developed. The user holds real surgical instruments, which are mounted with electromagnetic trackers to provide data to the virtual environment that is visualized. Feedback devices allow the user to “feel” vessels and nerves as they manipulate the virtual tools. In this way, microsurgery simulators combine instrument interactions, tissuedeformation, collision detection, and high-resolution graphics to allow realistic training in a virtual environment. Virtual models are poised to become the tool of choice in microsurgical training.
Asking for Alternatives
Many residents feel uncomfortable about animal laboratories in their training. When Carolyn Menendez, a third-year surgical resident at UCSF-Fresno learned she would be expected to participate in a live rat laboratory as part of a microsurgery rotation, she knew she wanted no part of it.
“I was shocked to learn that the preparation for our plastic surgery rotation involved a lab in which we’d cut off rats’ tails to practice reattaching them,” she says. “I knew there were better ways to perfect my skills without harming live animals.”
Ms. Menendez immediately set up a meeting with the residency director to ask for an alternative and was allowed to opt out of the animal lab. Sometimes, all you have to do is ask.