## 1 Introduction  
Gastrointestinal procedures are common and effective diagnostic and therapeutic tools for gastrointestinal diseases. With the increased clinical application of gastrointestinal procedures, an increasing number of medical residents need related training. Traditional endoscopic training is supervised and patient-based, but this method is not effective, as it usually involves only one operator at a time. The lack of experience among endoscopy trainees could increase the risk of patient discomfort and dissatisfaction, thus extending the operation time [1, 2]. Medical simulation can improve trainees' professional skills in a risk-free environment, especially for surgical procedures. For the gastrointestinal tract, simulation-based training is becoming an inherent part of medical training. The existing simulators are physical/mechanical, animal models (both in vivo and ex vivo), or computerized. However, these simulations have their advantages and disadvantages. Conventional mechanical simulators provide natural tactile feedback but lack realism and complexity in simulating the human structure [3; 4; 5]. Animal models can provide actual haptic feedback, allowing trainees to experience authentic clinical interventions [3], but are expensive and difficult to collect and maintain. Computerized simulators can provide multiple endoscopic procedures, anatomies, and interventions for training but lack realistic force feedback and are not cost-effective [3]. Due to rapid technological advancements, three-dimensional (3D)-printed models have been extensively employed in surgical planning and medical education. These 3D-printed models allow direct visualization of anatomical structures and provide a tactile experience for practice [6; 7]. In surgical planning, 3D patient-specific printing technology can help surgeons to understand complex anatomical relationships and determine which structures can be safely altered or removed. Compared with conventional 2-dimensional or 3D imaging, a 3D-printed model can provide more complex information for surgical planning in a shorter timeframe [8]. Three-dimensional-printed models have been utilized for preoperative assessment and surgical training in various conditions, including coronary artery disease, congenital heart disease, aortic disease, renal disease, and hepatobiliary disease [9; 10; 11; 12]. Studies have demonstrated the clinical value of using patient-specific 3D-printed models in guiding and simulating surgical planning, particularly for complex or challenging conditions, with advantages such as reducing the operating time, perioperative risks, and procedure-associated complications [9; 10; 11; 12]. Recently, 3D-printed models have been utilized for gastrointestinal tract applications such as esophageal stents and presurgical evaluation for gastrointestinal cancer [13; 14]. In these studies, the 3D-printed patient-specific models are durable, inexpensive, easy to produce, and achieve anatomical realism. Therefore, 3D-printed gastrointestinal models can be valuable, with the potential to serve as training models for presurgical planning and education. In a recent systematic review and meta-analysis, [PERSON] et al. analyzed 25 studies regarding the clinical benefits of using 3D-printed models on the clinical outcomes of metabolic surgery [14], emphasizing the accuracy of 3D-printed models for volumetric assessments of postoperative anatomy. Furthermore, 3D-printed models play an important role in patient and clinician education, thus contributing to improving postoperative outcomes. However, over the last decade, studies of 3D-printed gastrointestinal models have used only small sample studies or presented case reports (Figure 1). A review by [PERSON] et al. highlighted the value of 3D printing in colorectal surgery [15]. However, the 3D-printed models in this review were only vascular, pelvic, and anorectal fistulas. There is a lack of systematic research on 3D-printed gastrointestinal tract models for surgical planning and medical training.