Research Article: 3D-printed phantom study for investigating stent abutment during gastroduodenal stent placement for gastric outlet obstruction

Date Published: September 25, 2017

Publisher: Springer International Publishing

Author(s): Guk Bae Kim, Jung-Hoon Park, Ho-Young Song, Namkug Kim, Hyun Kyung Song, Min Tae Kim, Kun Yung Kim, Jiaywei Tsauo, Eun Jung Jun, Do Hoon Kim, Gin Hyug Lee.

http://doi.org/10.1186/s41205-017-0017-0

Abstract

Placing a self-expandable metallic stent (SEMS) is safe and effective for the palliative treatment of malignant gastroduodenal (GD) strictures. SEMS abutment in the duodenal wall is associated with increased food impaction, resulting in higher stent malfunction and shorter stent patency. The desire to evaluate the mechanism and significance of stent abutment led us to design an in vitro experiment using a flexible anthropomorphic three-dimensional (3D)-printed GD phantom model.

A GD phantom was fabricated using 3D printer data after performing computed tomography gastrography. A partially covered (PC) or fully covered (FC) stent was placed so that its distal end abutted onto the duodenal wall in groups PC-1 and FC-1 or its distal end was sufficiently directed caudally in groups PC-2 and FC-2. The elapsed times of the inflowing of three diets (liquid, soft, and solid) were measured in the GD phantom under fluoroscopic guidance. There was no significant difference in the mean elapsed times for the liquid diet among the four groups. For the soft diet, the mean elapsed times in groups PC-1 and FC-1 were longer than those in groups PC-2 and FC-2 (P = 0.018 and P < 0.001, respectively). For the solid diet, the mean elapsed time in group PC-1 was longer than that in group PC-2 (P < 0.001). The solid diet could not pass in group FC-1 due to food impaction. The mean elapsed times were significantly longer in groups FC-1 and FC-2 than in groups PC-1 and PC-2 for soft and solid diets (all P < 0.001). This flexible anthropomorphic 3D–printed GD phantom study revealed that stent abutment can cause prolonged passage of soft and solid diets through the stent as well as impaction of solid diets into the stent.

Partial Text

The placement of a partially covered (PC) or fully covered (FC) self-expandable metallic stent (SEMS) is safe, easy, and effective for the palliative treatment of malignant gastroduodenal (GD) strictures [1–7]. Their overall technical and clinical success rates have been reported to be 94 to 100% and 94 to 94.8%, respectively, in studies that have included >74 but <213 patients [3–7]. Recently, our experience with the placement of a SEMS bridging the gastric pylorus for gastric outlet obstruction (GOO) caused by inoperable gastric cancer showed that the distal end of the stent abutted onto the duodenal wall in 107 (33.6%) of 318 patients. Further, stent abutment was associated with increased food impaction, resulting in higher stent malfunction and shorter stent patency [8]. The mean elapsed times for the liquid diet were not significantly different among the four groups (4.21 ± 0.04 s in group PC-1, 4.22 ± 0.04 s in group FC-1, 4.22 ± 0.05 s in group PC-2, and 4.23 ± 0.04 s in group FC-2). For the soft diet, the mean elapsed times were longer in groups PC-1 (7.00 ± 0.09 s) and FC-1 (9.06 ± 0.25 s) than in groups PC-2 (6.88 ± 0.10 s) and FC-2 (8.32 ± 0.10 s), with a statistically significant difference between the stent types (P = 0.018 and P < 0.001, respectively). For the solid diet, the mean elapsed times were longer in group PC-1 (32.35 ± 1.10 s) than in group PC-2 (24.53 ± 0.37 s) (P < 0.001). The mean elapsed time was 42.78 ± 1.33 s in group FC-2; conversely, in group FC-1, the solid diet could not pass through the FC stent because food impaction occurred immediately (Fig. 4).Fig. 4Representative radiographs of food inflowing in the GD phantom. a Radiograph obtained 20 s after inflowing in group PC-1 using the liquid diet shows the disturbance-free passage of radiopaque liquid diet. b Radiographs obtained 20 s after inflowing in groups FC-1 and FC-2 using the soft diet show the narrowing passage of the diet (arrowhead) though the distal end of the stent in group FC-1 and relatively better passage of the diet (arrowhead) though the distal end of the stent in group FC-2. c Radiographs obtained 20 s after inflowing in groups PC-1 and FC-1 using the solid diet show poor passage of the diet through the wire mesh of the stent (arrowhead) in group PC-1 and food impaction (arrowheads) in group FC-1 It is still not known how food materials move down the GD pathway according to SEMS locations and stent types (PC or FC). Park et al. recently reported that patients with stent abutment were more likely to have food impaction than those without stent abutment, resulting in higher rates of stent malfunction and shorter stent patency durations [8]. They indicated that the distal landing zone of the stent should be located in the second portion of the duodenum to prevent stent abutment. The concept of stent abutment may be useful for avoiding stent malfunction, particularly from food impaction. An experimental study that quantitatively explains food inflowing differences according to stent abutment, even using an artificial GD phantom model, is required. The findings of the present study revealed that stent abutment can cause prolonged passage of soft and solid diets through the stent and can also cause impaction of the solid diet into the stent. Therefore, we believe that when a stent is placed in the gastric outlet bridging the gastric pylorus, the distal end of the stent should be directed caudally to prevent stent abutment.   Source: http://doi.org/10.1186/s41205-017-0017-0

 

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