Balloon sheaths for gastrointestinal guidance and access: a preliminary phantom study

Modelling and manufacturing of 3D-printed, patient-specific, and anthropomorphic gastric phantoms: a pilot study

Interventional devices including intragastric balloons are widely used to treat obesity. This study aims to develop 3D-printed, patient-specific, and anthropomorphic gastric phantoms with mechanical properties similar to those of human stomach. Using computed tomography gastrography (CTG) images of three patients, gastric phantoms were modelled through shape registration to align the stomach shapes of three different phases. Shape accuracies of the original gastric models versus the 3D-printed phantoms were compared using landmark distances. The mechanical properties (elongation and tensile strength), number of silicone coatings (0, 2, and 8 times), and specimen hardness (50, 60, and 70 Shore A) of three materials (Agilus, Elastic, and Flexa) were evaluated. Registration accuracy was significantly lower between the arterial and portal phases (3.16 ± 0.80 mm) than that between the portal and delayed phases (8.92 ± 0.96 mm). The mean shape accuracy difference was less than 10 mm. The mean elongations and tensile strengths of the Agilus, Elastic, and Flexa were 264%, 145%, and 146% and 1.14, 1.59, and 2.15 MPa, respectively, and their mechanical properties differed significantly (all p < 0.05). Elongation and tensile strength assessments, CTG image registration and 3D printing resulted in highly realistic and patient-specific gastric phantoms with reasonable shape accuracies.

Usefulness of a guiding sheath for fluoroscopic stent placement in patients with malignant gastroduodenal obstruction

BACKGROUND

Self-expandable metallic stent placement is widely used to manage malignant gastroduodenal obstructions. However, there are difficulties in negotiating a guidewire (GW) and a stent delivery system (SDS).

PURPOSE

To investigate feasibility, usefulness, and safety of a guiding sheath for fluoroscopic stent placement in patients with malignant gastroduodenal obstructions.

MATERIAL AND METHODS

In July 2001 to August 2011, 726 patients with malignant gastroduodenal obstructions underwent stent placement. Guiding sheath was used in patients in whom a GW could not be passed through the obstruction and a SDS failed to reach the obstruction. Sheath usefulness was evaluated based on the ability of the sheath to successfully assist. The technical success rate and the most frequent reasons for the use of a sheath were evaluated.

RESULTS

The guiding sheath was needed in 148 of 726 patients (20%). The overall technical success rate was 98% with the guiding sheath. In two of 148 patients, stent placement failed because, the GW could not be passed through the obstruction, in the other, the SDS could not be passed. A minority of patients reported mild discomfort. Patients with pancreatic cancer and duodenal obstruction were significantly more likely to require the use of guiding sheaths (P = 0.002, P < 0.001, respectively).

CONCLUSION

Using a guiding sheath for fluoroscopic stent placement appears to be feasible, useful and safe in patients with malignant gastroduodenal obstructions.