## 3 Results
### Three-Dimensional Printing Details
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**Article** & **Vear** & **Purpose** & \begin{tabular}{c} **County of** \\ **Origin** \\ \end{tabular} & **Study Design** & **Sample Size** & **Key Findings** & **Limitations** \\ \hline [PERSON] & 2024 & \begin{tabular}{c} To create a 3D rectal model, \\ including the tumor and \\ arounding structures, to \\ help in preoperative and \\ intraoperative planning. \\ \end{tabular} & USA & Case report & \begin{tabular}{c} Gastrointestinal \\ stromal tumor model, \\ n = 1 \\ \end{tabular} & \begin{tabular}{c} The 3D model added value to \\ patient care and helped the patient \\ understand the surgery. \\ \end{tabular} & \begin{tabular}{c} The model did not provide \\ any new information or \\ alter the surgical plan. The \\ more expensive model did \\ not offer additional or \\ better information than the \\ cheaper one. \\ \end{tabular} \\ [PERSON] et al. [42] & 2024 & \begin{tabular}{c} To create a 3D-printed \\ gastrointestinal model \\ using the PVA/PAM \\ tidimensional hydrogel. \\ \end{tabular} & China & Experimental study & \begin{tabular}{c} Novel elastic hydrogel \\ model for surgical \\ training. n = 1 \\ \end{tabular} & \
\begin{tabular}{c} The new-material 3D-printed \\ model exhibited positive qualities \\ in the following factors: \\ appearance levels, overall \\ difficulty, stomach wall structure, \\ tissue elasticity, and tactile \\ feedback. \\ \end{tabular} &
\begin{tabular}{c} The new-material 3D-printed \\ model exhibits the \\ model needs to be \\ improved, particularly in \\ terms of enhancing \\ subretinal skills and \\ shortening the learning \\ curve. \\ \end{tabular} \\ \hline \hline \end{tabular}
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Table 2: _Cont._  
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3.3.1. Three-Dimensional Printing Processing and Materials  
Of the 25 studies, 16 (67%) used CT imaging for 3D printing [19; 20; 21; 22; 24; 26; 28; 29; 30; 31; 32; 33; 36; 39; 40; 41], 1 used both CT and magnetic resonance imaging [42], and the remaining 8 did not mention the data resource used for printing. Eight studies mentioned the printing method. Six used fused-deposition modeling (FDM) [24; 30; 33; 39; 40; 42], and two used stereolithography printing modeling [28; 32]. The 3D printing time varied from 6 to 48 h. The highest printing cost was USD 1175 [18], and the lowest was USD 10 [33]. Silicone was the most commonly used material, accounting for 46% of the studies [18; 19; 22; 24; 25; 27; 29; 32; 34; 35; 36; 39; 40]. The second most commonly used material was polylactic acid (PLA) [23; 25; 33; 35; 39]. Other printing materials included resin, rubber-like material, PlatSil Gel-10, and plastic (Figure 3). In [PERSON] et al. 's study, PVA/polyacrylamideamide (PAM) hydrogels were utilized as a novel material for gastrointestinal 3D printing. Six studies concertedly used two materials to print models [25; 27; 32; 35; 39; 41]. Five studies reported material hardness [24; 29; 32; 35; 36]. Two silicone materials with a Shore hardness of A10 were used [24; 29]. One study compared three rubber-like materials with different Shore hardnesses (Shore A 50, 60, 70) [32]. The remaining two studies used silicone materials with hardnesses of 00-10, 00-25, 00-30, and 40 [35; 36]. Figure 2: PRISMA flow chart showing use of search strategy to locate eligible studies.