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International Journal of Bioprinting 3D printing in gastroenterology

tomographic images acquired by enhanced CT or MRI; addition to hollow organs, because of their non-deformable
or, better, through virtual 3D reconstruction by software. nature. Igami et al. reported that the 3DP liver model helped
Compared to these imaging modalities, printed 3D models to plan a resection strategy for a small metastatic tumor
provide more detailed visual and tactile information and that could be neither touched nor seen during laparoscopic
experience. Furthermore, surgeons could rehearse surgical surgery and increased the success rate of R0 resection .
[20]
procedures on the real model to select surgical devices, The model could distinctly locate and describe tumors,
choose an optimized operative approach, and define other bile ducts, and blood vessels to predict the functional
intraoperative matters that need attention. status of the liver postresection. However, the printed
model was whitish, so the vessels had to be dyed manually.
2.1. Operative planning and guidance Later, in 2017, Witowski et al. also reported a similar but
Preoperative planning and intraoperative guidance are much more cost-effective 3DP colorectal liver metastatic
some of the most researched topics regarding the esophageal model . The researchers used desktop-fused deposition
[21]
aspect. Most studies conclude that 3D models, especially modeling (FDM) printing technology, which is cheaper
of blood vessels, help identify anatomical variants, reduce than jetting. However, this FDM printer could only print
operative time and blood loss, and optimize the operative a small part of the whole model at a time, and assembling
approach. This is especially true when encountering multiple parts was needed. Therefore, this printing strategy
complicated cases. In 2015, Dickinson et al. of Mayo is semiautomated, time-consuming, and usually requires
Clinic reported two complex cases of aortoesophageal several printers, despite costing less than others. Similar
fistula complicated by previous cervical esophagostomy successful outcomes were reported for retroperitoneal
and thoracoplasty and multiple esophageal diverticula tumors and for avoiding large-for-size syndrome in
[22]
secondary to esophageal dysmotility . The printed life- pediatric liver transplantation . Interestingly, Villarreal
[14]
[23]
size models helped doctors examine anatomical structures et al. reported two cases in which 3DP models were used
closely and directly, providing valuable chances for in the planning and practice of complex hepatic separation
operational rehearsal and multidisciplinary consultation. of conjoined twins . In this case, the authors referred to
[24]
Hamada et al. also reported a case where a surgery for similar 3DP models documented in previously published
cT3N4M0 stage III esophageal cancer was complicated by literature.
major vascular malformation (double aortic arch) . The
[15]
authors firmly acknowledged the efficacy of the 3DP model Fistulas are not uncommon in general surgery and
for preoperative simulation. Much of the difficulties they abdominal diseases. They are sometimes complicated
faced during surgery were what they had expected when because the fistula may involve multiple organs or tissues,
simulating on the model. A similar function was reported and the fistula canals may vary. Therefore, researchers
in a robotic surgery for guiding anti-reflux surgery used 3D printing as an isolation technique to illustrate
complicated by tortuous thoracic aorta compression . the fistula’s complete picture. Huang et al. employed 3D
[16]
printing to construct a stent that could match well with
Regarding the colic aspect, Garcia-Granero the angled intestinal tract (105°) that connected the
et al. reported using 3DP models to facilitate the enterocutaneous fistula . The stent significantly reduced
[25]
planning of laparoscopic right hemicolectomy and D3 enteric effluent loss, allowing enteric nutrition and future
lymphadenectomy . The model contained only blood fistula resection; however, a small amount of effluent
[17]
vessels because the lymph nodes are usually located leakage still occurred after the postural shift, indicating
around the gastrocolic trunk of Henle (GCTH), where its a need for further improvement in printing precision or
origin from the mesentery is often variable. No obvious material. One of the most common non-traumatic causes
intraoperative bleeding was recorded, and all D3 nodes for enteric fistula might be attributed to Crohn’s disease.
were found negative. Hojo et al. also printed a 3D model to Guz et al. reported a case in which an MRI image-based
rehearse laparoscopic surgery of descending colon cancer 3DP model provided a direct rotatable view and tactility
[18]
complicated by a 69 mm abdominal aortic aneurysm . of the location and degree of Crohn’s disease-related
The authors acknowledged the benefit of planning port sites perianal fistula . The authors argued that this technique
[26]
and avoiding vascular injury and postoperative adhesion. could do more than merely surgical planning by possibly
For rectal surgery, Hamabe et al. printed 3D pelvic models lowering interobserver bias in interpreting radiological
for rectal cancer that could be sagittally cleaved for clearer information.
inspection. However, the printing material was hard and
not elastic, leading to less operational simulation value .
[19]
2.2. Education and research
The 3DP model is particularly helpful for simulating Another major function of the 3DP model is facilitating
solid organs, such as the liver, spleen, and pancreas, in activities in education for medical students, residents,

Volume 9 Issue 6 (2023) 153 https://doi.org/10.36922/ijb.0149