Revolutionary ‘plastination’ process breathes new life into cadavers

A skinless soccer player hangs in mid-air, his attention riveted on the ball that’s suspended above his outstretched leg. His superficial and intermediate muscle layers are exposed, as are the muscles of the basketball player nearby whose grey matter is visible through his open skull.

These athletes are part of BODY WORLDS 3, the brainchild of anatomist Gunther von Hagens, MD, inventor of the specimen preservation process called “plastination.” The exhibits feature more than 200 real human specimens, including whole-body plastinates, individual organs, organ configurations, and transparent body slices. They provide lessons in anatomy, physiology, and health; showcase the mechanics of hip and knee implants, the impact of diseases on the body, and the effects of tobacco consumption; and attract thousands of visitors wherever they are displayed.

“The purpose of plastination, from its very inception, was a scientific one, to educate medical students,” Dr. von Hagens has said. “But the interest of lay people in the plastinated specimens inspired me to think of public exhibitions, which was followed by the realization that I had to offer a heightened sense of aesthetics to avoid shocking the public and to capture its imagination.”

The birth of plastination
As a student and anatomy assistant at the University of Heidelberg’s Institute of Anatomy in 1977, Dr. von Hagens needed to prepare slices of human kidneys for a research project. The usual process of embedding the kidneys in paraffin and cutting thin slices seemed like too much wasted effort, considering that he only needed every fiftieth slice. As he watched a worker slice ham at a local butcher shop one day, Dr. von Hagens was inspired to use a “rotary blade cutter” to prepare the slices. This innovation was the first step in what would become a unique process for specimen preservation.

First, Dr. von Hagens embedded the kidney slices in Plexiglass. Then, he used a vacuum to extract the air bubbles that had formed when stirring the curing agent. The bubbles gave him a second realization: If he saturated a kidney slice with acetone and placed it under a vacuum to extract the acetone bubbles, the slice would be preserved, almost like plastic.

The first experiment produced a pitch black, shrunken kidney. A week later, after making some adjustments, Dr. von Hagens repeated the experiment. He then cured the kidney slice in a laboratory kiln. The result? The first real sample of a plastinated organ.

How plastination works
The plastination process begins by pumping formaldehyde into the body through the arteries, killing all bacteria and chemically stopping the decay of tissue. Dissection tools are used to remove the skin, as well as fatty and connective tissues to prepare the individual anatomical structures.

Next, the body is placed in an acetone bath to dissolve water and soluble fats. A polymer solution can then be introduced and delivered into the specimen through vacuum-forced impregnation. During this process, the specimen is immersed in a reactive polymer solution—such as silicone rubber, epoxy, or other reactive resins or elastomers—and then placed in a vacuum chamber. The vacuum removes the acetone from the specimen and helps the polymer to penetrate every cell.

After vacuum impregnation, the body can be placed into any position desired. Every anatomical structure is properly aligned and fixed using wires, needles, clamps, and foam blocks.

Finally, the specimen is hardened with gas, light, or heat, depending on the polymer used. The result is a rigid, odor-free plastinate. Body cells and natural surface structures retain their original forms and are identical to their condition prior to preservation, even at the microscopic level.

The labor-intensive process can take up to 6 months for a whole-body specimen, and as long as 3 years for elaborate creations such as Horse and Rider, a plastinate of a rearing horse and a rider who holds the horse’s brain in one hand, and his own brain in the other. Typically, it takes between 1,000 and 1,500 hours of work to create a whole-body plastinate.

“Sheet plastination” is a special variation of the preservation technique in which slices of a frozen body are plastinated. These plastinated organs and body slices are useful tools for teaching cross-sectional anatomy.

The Institute for Plastination
In 1993, Dr. von Hagens established the Heidelberg-based Institute for Plastination, where techniques for preparing whole-body plastinates and transparent slices of whole bodies are perfected.

The Institute’s aim is to produce human specimens and make them available for basic and continuing medical training as well as for the general medical education of the public. The educational specimens are used for anatomic instruction at universities and other teaching institutions. The Institute also provides plastination expertise to teaching organizations around the world and to the more than 400 plastination laboratories that exist in 40 countries.

Body donations
The Institute also manages the Body Donation Program, which was established in 1982. The program is the primary source of the specimens used in the BODY WORLDS exhibitions. Donors will their bodies during their lifetime to be part of the exhibitions; a small number of other specimens have come from established morphologic institutes, such as anatomy and pathology programs, and historic anatomic collections.

As of April 2006, The Institute’s Body Donation Program had a roster of 6,800 potential donors—including some 200 North Americans—who have declared during their lifetime that their bodies should be made available for plastination after their deaths. The program also has 350 people who are already deceased on its donor roster.

The future of plastination
The plastination process continues to be refined and improved. Research is ongoing regarding new polymers that may retain the color of tissues and improve plastination results for specimens that are difficult to preserve, such as the eye. Additional investigations are exploring how slice plastinates can show complex systems such as the blood supply to the bones or wrist and how subtle structures—such as the muscles and nerves surrounding the prostate—can be displayed.

Jennie McKee is a staff writer for AAOS Now. She can be reached at mckee@aaos.org

Visiting BODY WORLDS
BODY WORLDS exhibitions have traveled the globe for 10 years and have attracted nearly 25 million visitors in cities across Asia, Europe, the United States, and Canada. The original BODY WORLDS exhibit is on display through Jan. 6, 2008, in Charlotte, N.C.; BODY WORLDS 2 is in San Jose, Calif., through Jan. 26, 2008; and BODY WORLDS 3 is in St. Louis, Mo., through March 2, 2008.