Boning up on anatomy: Plastic horse bones might be the way of the future

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Partial views of the scapula, where (b) and (c) are the original bones; (a) and (d) are models. Photo: https://doi.org/10.1186/s41205-019-0050-2

Learning anatomy is an essential part of any veterinarian’s education, and there is nothing like the hands-on approach.

However, enabling students to get their hands on real body parts isn’t necessarily cheap or easy.

Daniela de Alcântara Leite dos Reis and her colleagues, writing in the journal 3D Printing in Medicine, note that there are several obstacles that hinder easily obtaining and preparing anatomical specimens.

There is the high cost of preserving cadavers and acquiring equipment needed to maintain them. These have led to many laboratories to abandon these practices.

“Many institutions and universities primarily rely on the use of books with two-dimensional images and written information, as well as classes, through which information about clinical cases are passed verbally,” the researchers from the University of São Paulo in Brazil wrote.

Photographs are often used for teaching anatomy, given the lack of feasibility of using corpses for such studies.

“However, researchers have shown that such methods are more effective for learning when combined with other methods, such as the use of anatomical models.”

The authors noted that although the theoretical teaching of anatomy is extremely important, practical studies are essential to consolidate the theoretical aspects.

The scapula could only be printed at 80 percent of its original size. Photo: https://doi.org/10.1186/s41205-019-0050-2

“For practical teaching to be successful, it is important that the anatomical specimens being used are in good condition; the color, texture, flexibility, and other characteristics accurately represent those found in a living animal.”

Technology can contribute to teaching veterinary anatomy, and make it more interesting and accurate, they said – and it is here that three-dimensional (3D) scanning and printing could prove useful.

For their study, the researchers used 3D scanning and printing to recreate the limb of an adult horse.

The scapula, humerus, radius and ulna, carpus and phalanges of a real horse were sourced from the Veterinary Anatomy Laboratory at the university. They were scanned and printed in plastic, together with a support resin.

The skeletal parts were digitized using a Canadian-sourced “Go!SCAN 3D” model Creaform 3D scanner which features two high-definition digital cameras. The Mojo 3D printer used for the study came from an Israeli company.

Views of the horse humerus. The plastic bones are paler.  Photo: https://doi.org/10.1186/s41205-019-0050-2

The humerus was the bone that took the most time to print, at 14 hours.

The scapula consumed the most materials during printing, at 43.8 cubic centimeters.

The anatomical characteristics and measurements of the plastic reproductions were then carefully compared to the real deal.

They found no significant statistical difference between the models and the original anatomical parts.

However, the natural bones weighed much more than their plastic models. For example, the actual horse’s humerus weighed 763 grams while its model – which was 80 percent of the original size due to the size limitations of the printer – weighed 148 grams. The printed bones were roughly one-fifth the weight of the originals.

Similarly, the scapula was only 75% of its original size, and even then had to be produced in two parts and glued together.

The remaining smaller bones were reproduced to actual size.

The study team concluded that models of animal bones can be reproduced using 3D printing technology for use in veterinary education. The plastic replicas were accurate and their visual features similar to the originals. Anatomical features were readily identified.

A horse metacarpal, with the printed plastic replica at left.

They described the plastic printing as relatively cheap, with the most expensive bone, the humerus, costing about $US70.45. They expected this cost could be lowered.

“Additionally, by scanning the parts, digital files are created, and these can be printed in companies that offer a 3D printing service, which may be a useful alternative in situations when the institution does not own a 3D printer.”

The costs involved in manufacturing the parts via 3D printing are still less than sourcing real body parts.

“The manufactured models are sufficiently detailed in their anatomy to constitute an alternative teaching material.”

The authors noted that plastic models of anatomical parts are on the market and are often used in some educational institutions.

“These models are copies or molds produced on a large scale based on ‘hypothetical’ or ‘caricature’ anatomical specimens and they often lack specific and important anatomical details.

“Although they may be suitable for some teaching programs that have lower academic requirements, they are not ideal for teaching anatomy at the academic level expected of students studying veterinary medicine.”

The authors said the effectiveness of learning with the 3D-printed models will be analyzed in another study, which will assess the performance of students in a classroom using the printed models and real bones, over two years, based on practical exams.

Comparative assessment of anatomical details of thoracic limb bones of a horse to that of models produced via scanning and 3D printing
Daniela de Alcântara Leite dos Reis, Beatriz Laura Rojas Gouveia, José Carlos Rosa Júnior & Antônio Chaves de Assis Neto
3D Printing in Medicine, volume 5, Article number: 13 (2019) https://doi.org/10.1186/s41205-019-0050-2

The study, published under a Creative Commons license, can be read here

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