Researchers have developed a new technique for 3D printing patient-specific prostate glands using polymers that accurately model a prostate’s dimensions and physical properties while also providing quantitative tactile feedback. The new model, developed by investigators at the University of Minnesota (UMN) Twin Cities and described in the December issue of Advanced Materials Technologies, could enable better preoperative planning and rehearsal that may help improve surgical outcomes in men with prostate cancer (PCa).

“Some preliminary clinical rehearsals, including suturing and endoscopic manipulations, have been performed by medical professionals on these organ models,” said first author Kaiyan Qiu, PhD, a postdoctoral scientist in the department of mechanical engineering. “We foresee that with some improvements to the process, this could be used as an integrated tool for diagnosis and surgical rehearsal as well as for training medical students, and educating patients.”

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Possible game changer 

Aided by magnetic resonance imaging, mechanical engineers and medical doctors in a special collaboration created a 3D printed prostate model that has the same tactile sensation, pliability, and texture as the real gland. Principal investigator Michael C. McAlpine, PhD, associate professor of mechanical engineering, said 3D printed organ models are typically made of hard plastic. His team, however, has developed a unique 3D printer that uses customized silicone-based polymer inks, which were developed by carefully studying the mechanical properties of actual prostate tissue. They contend that their 3D printed prostate models could be a game changer for organ models. One of the coauthors, Ghazaleh Haghiashtiani, also in the department of mechanical engineering, said previous 3D printed organ models have been anatomically correct, but they lacked precise mimicry of the physical properties of real tissue. Haghiashtiani said this has hindered their ability to accurately predict and replicate organ physical behaviors, such as deformation and reaction force during surgical handling.

“In this work, customized polymeric materials have been developed that have properties closely matching the real prostate tissue in terms of static and dynamic mechanical properties, hardness and optical characteristics,” Haghiashtiani told Renal & Urology News. “The organ models in this work include integrated sensors that provide quantitative electrical feedback to the applied mechanical stimulation.”

Real-time feedback

Haghiashtiani said this electrical feedback provides physicians with the ability to quantify and control the force ranges they apply to the organ during preoperative rehearsal and training. This may help lower the chance of adversely affecting healthy tissue, subsequently lowering the risk of urinary problems and erectile dysfunction. When the prostate model is touched, the sensors instantly send a visual readout of how much pressure is applied, showing the surgeons how hard they are pressing on the model and whether the amount of pressure applied is appropriate or could damage healthy tissue.

Dr Qiu said the ability to have quantitative, real-time feedback could change how surgeons think about personalized medicine and preoperative practice. “The combination of 3D printing process along with customizable tissue-mimicking materials provide a platform for creating real life, patient-specific organ models,” he said. “This could directly enhance their performance in the actual surgery, and thus could decrease the rate of errors and complications during the actual surgery and possibly improve morbidity or mortality.”

In the future, even more complicated organ models could be developed for treating other tumor types, including renal cell carcinoma, by using multiple inks to mimic different tissue properties. Eventually it may even be possible to create 3D organs for transplantation, according to the researchers.

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Important questions remain

Matthew J. Resnick, MD, assistant professor of urologic surgery and health policy at Vanderbilt University Medical Center in Nashville, Tennessee, said it is too early to know how helpful these models will be in terms of morbidity and mortality. While 3D prostate models may facilitate development of patient-specific surgical plans, important questions remain regarding whether these plans will translate into improvements in either oncologic or functional outcomes, he said. Dr Resnick said it is important that this technology is not oversold.

“It is possible that a 3D prostate model may offer insights surrounding the precise location and extent of disease, and these insights may, at an individual patient level, mediate surgical decision-making, specifically surrounding the extent of nerve-sparing,” Dr Resnick said. “Nonetheless, it will be critically important to rigorously evaluate the impact of these models in diverse populations to characterize the extent to which the use of such models truly map to measureable improvements in outcomes.”