OpenHELP (Heidelberg laparoscopy phantom): development of an open-source surgical evaluation and training tool

Abstract

BackgroundApart from animal testing and clinical trials, surgical research and laparoscopic training mainly rely on phantoms. The aim of this project was to design a phantom with realistic anatomy and haptic characteristics, modular design and easy reproducibility. The phantom was named open-source Heidelberg laparoscopic phantom (OpenHELP) and serves as an open-source platform. MethodsThe phantom was based on an anonymized CT scan of a male patient. The anatomical structures were segmented to obtain digital three-dimensional models of the torso and the organs. The digital models were materialized via rapid prototyping. One flexible, using an elastic abdominal wall, and one rigid method, using a plastic shell, to simulate pneumoperitoneum were developed. Artificial organ production was carried out sequentially starting from raw gypsum models to silicone molds to final silicone casts. The reproduction accuracy was exemplarily evaluated for ten silicone rectum models by comparing the digital 3D surface of the original rectum with CT scan by calculating the root mean square error of surface variations. Haptic realism was also evaluated to find the most realistic silicone compositions on a visual analog scale (VAS, 0–10).ResultsThe rigid and durable plastic torso and soft silicone organs of the abdominal cavity were successfully produced. A simulation of pneumoperitoneum could be created successfully by both methods. The reproduction accuracy of ten silicone rectum models showed an average root mean square error of 2.26 (0–11.48) mm. Haptic realism revealed an average value on a VAS of 7.25 (5.2–9.6) for the most realistic rectum.ConclusionThe OpenHELP phantom proved to be feasible and accurate. The phantom was consecutively applied frequently in the field of computer-assisted surgery at our institutions and is accessible as an open-source project at www.open-cas.org for the academic community.

X-ray computed tomography and additive manufacturing in medicine: a review

“…Further to this, Igami et al [63] and Isotani [72] drew attention respectively to the creation of multi-colour models of a single-material liver produced via SLA (later coloured with a dye) and a multi-material kidney produced via inkjetting; both using CAD models extracted from XCT data and used as an aid to surgical approach design. Kondo et al [69] and Kenngott et al [80] also produced multi-coloured, single-material models through the use of binder jetting with XCT. The former authors produced models of unruptured cerebral aneurysms for neurosurgical simulation, while the latter produced an anatomically correct haptic torso phantom on an open source platform for surgical evaluation and training (see Fig.…”

“…In keeping with these likely developments, it is worth noting that as XCT has increased in use as a metrological tool [8], a number of medical authors have similarly adopted the technology beyond its ability to recreate geometries and as a medical inspection device. Examples of this include the post-operative assessment of implant positional and angular deviation compared to the intended positioning [90], and the comparison between patient XCT data and XCT scans of AM models, through calculation of the root mean square error of surface variations [80]. Also of note as an aside to this section, Singh et al [97] recently presented a design for an AM training box to account for a lack of training objects in the field of endoscopic [63], top right: inkjetted kidney [72], centre: binder jetted cerebral aneurysm [69], bottom: binder jetted torso phantom [80].…”

Human organ phantoms for catheterization using the radiation crosslinking technique

“…Porcine organs and artificial organ phantoms made of synthetic polymers to simulate human organs have been developed and used for the evaluation of medical devices and training of medical staff. [1][2][3][4] Although porcine organs have physical, chemical, and biological characteristics similar to those of the human body, it is difficult to obtain reproducible data and proper evaluation due to age and growth environment, differences in the elapsed time since death, and storage conditions. Moreover, a systematic experimental design to evaluate the variance of organ characteristics in pigs has not yet been implemented.…”

“…Artificial organ phantoms made of synthetic polymers, such as, silicone, urethane elastomer, styrene elastomer, and polyvinyl alcohol (PVA) hydrogel, have been proposed and developed. [3][4][5][6] PVA hydrogel has been developed for surgical practice of surgical scalpel incisions, and its tactile sensation and sharpness are similar to those of an actual organ. Methods for fabricating evaluation devices for ablation catheters consisting of conductive resins, including thermochromic materials, and resin moldings impregnated with thermochromic colormemory microcapsules have also been reported.…”

Improving Surgical Training Phantoms by Hyperrealism: Deep Unpaired Image-to-Image Translation from Real Surgeries

“…Physical phantoms, e.g. made from silicone, suffer also from these drawbacks, but they provide excellent haptic feedback and tissue properties for stitching with authentic instruments and suture material [1,2]. However, their uniform appearance does not reflect the complex environment of a surgical scene.…”