Novel 3D-printing technique for caps to enable tailored therapeutic endoscopy

Ligation-assisted endoscopic submucosal resection following unroofing technique for small esophageal subepithelial lesions originating from the muscularis propria

BACKGROUND

The majority of esophageal subepithelial lesions originating from the muscularis propria (SEL-MPs) are benign in nature, although a subset may exhibit malignant characteristics. Conventional endoscopic resection techniques are time-consuming and lack efficacy for small SEL-MPs.

AIM

To evaluate the efficacy and safety of ligation-assisted endoscopic submucosal resection (ESMR-L) following unroofing technique for small esophageal SEL-MPs.

METHODS

From January 2021 to September 2023, 17 patients diagnosed with esophageal SEL-MPs underwent ESMR-L following unroofing technique at the endoscopy center of Shenzhen People's Hospital. Details of clinicopathological characteristics and clinical outcomes were collected and analyzed.

RESULTS

The mean age of the patients was 50.12 ± 12.65 years. The mean size of the tumors was 7.47 ± 2.83 mm and all cases achieved en bloc resection successfully. The average operation time was 12.2 minutes without any complications. Histopathology identified 2 Lesions (11.8%) as gastrointestinal stromal tumors at very low risk, 12 Lesions (70.6%) as leiomyoma and 3 Lesions (17.6%) as smooth muscle proliferation. No recurrence was found during the mean follow-up duration of 14.18 ± 9.62 months.

CONCLUSION

ESMR-L following roofing technique is an effective and safe technique for management of esophageal SEL-MPs smaller than 20 mm, but it cannot ensure en bloc resection and may require further treatment.

Effects of post-curing duration on the mechanical properties of complex 3D printed geometrical parts

This study aims to assess the efficacy of post-curing guidance supplied by 3D printing resin manufacturers. Current guidance applies generically to all geometries with the caveat that post-curing should be extended for 'large' or 'complex' geometries but specific guidance is not provided. Two vat-polymerisation 3D printers (Form3B, Figure 4 Standalone) were used to print test models in 6 biocompatible resins (Pro Black, Med White, Med Amber, Biomed Black, Biomed White, Biomed Amber). The test model is of a complex geometry whilst also housing ISO 527 test specimens in concentric layers. Two separate intervals of curing were applied (100%, 500% stated guidance) creating different curing treatments of the specimens throughout the model. Post processed test models were disassembled and pull testing performed on each of the specimens to assess the mechanical properties. The analysis showed that extending the curing duration had significant effects on the mechanical properties of some materials but not all. The layers of the model had a significant effect except for elongation at break for the Med Amber material. This research demonstrates that generic post-curing guidance regarding UV exposures is not sufficient to achieve homogenous material strength properties for complex geometries. Large variations in mechanical properties throughout the models suggest some material was not fully-cured. This raises a query if such materials as originally marketed as biocompatible are fully cured and therefore safe to use for medical applications involving complex geometries.

Comparison of efficiency and safety between dual-clip and rubber band-assisted ESD and conventional ESD for colonic lateral spreading tumors (LSTs) with different levels of technical difficulty: a retrospective case–control study

Background

Dual-clip and rubber band-assisted endoscopic submucosal dissection (DCRB-ESD) is a useful technique in the management of lateral spreading tumors (LSTs) of the colon and is suggested by researchers compared with conventional ESD (C-ESD). The aim of this retrospective study is to further analyze the efficiency and safety of DCRB-ESD in a setting with varying technical difficulties.

Methods

Patients who underwent endoscopic treatment (DCRB-ESD or C-ESD) due to LSTs between Jan 1st, 2019 and Jan 1st, 2022, were retrospectively collected. Patients were classified into the following two groups: the DCRB-ESD group (n = 46) and the C-ESD group (n = 81). Baselines were compared and propensity score matching (PSM) was employed to manage the heterogeneity. The technical difficulty and outcomes of the two groups were evaluated based on a semiquantitative model (CS-CRESD) previously described.

Results

The baseline characteristics of the two groups were balanced except sex and LST classification before PSM and were corrected after PSM. The median ESD operation time of DCRB-ESD was shorter than that of C-ESD (32 vs 41 and 30 vs 44 before and after PSM respectively, P < 0.05). The operation durations of cases with different CS-CRESD scores were different (P < 0.05). In the subgroup with a score of 0, DCRB-ESD showed no advantage than C-ESD in terms of operation duration before and after PSM. In subgroups with a score of 1–3, DCRB-ESD was faster than C-ESD. In subgroups with a score of 4–5, the between-group operation duration was not significantly different due to the limited number of cases, although the median time of DCRB-ESD was shorter. The R0 resection rates, curative resection, complications, and additional surgery in both groups were not significantly different. No adverse events, such as a clip falling off or rubber band rupturing occurred during this study.

Conclusion

DCRB-ESD was an efficient and safe procedure in the management of colonic LSTs. With DCRB-ESD, the operation duration of difficult cases can be shortened without sacrificing complication risk. However, not all cases would benefit from DCRB-ESD. For easy cases (CS-CRESD score = 0), DCRB-ESD may not be prior to C-ESD by experienced endoscopists. A pre-ESD technical difficulty evaluation was recommended to decide whether to perform DCRB-ESD or not.

Three-Dimensional Printing of Medical Devices Used Directly to Treat Patients: A Systematic Review

Until recently, three-dimensional (3D) printing/additive manufacturing has not been used extensively to create medical devices intended for actual clinical use, primarily on patient safety and regulatory grounds. However, in recent years there have been advances in materials, printers, and experience, leading to increased clinical use. The aim of this study was to perform a structured systematic review of 3D-printed medical devices used directly in patient treatment. A search of 13 databases was performed to identify studies of 3D-printed medical devices, detailing fabrication technology and materials employed, clinical application, and clinical outcome. One hundred and ten papers describing one hundred and forty medical devices were identified and analyzed. A considerable increase was identified in the use of 3D printing to produce medical devices directly for clinical use in the past 3 years. This is dominated by printing of patient-specific implants and surgical guides for use in orthopedics and orthopedic oncology, but there is a trend of increased use across other clinical specialties. The prevailing material/3D-printing technology used were titanium alloy/electron beam melting for implants, and polyamide/selective laser sintering or polylactic acid/fused deposition modeling for surgical guides and instruments. A detailed analysis across medical applications by technology and materials is provided, as well as a commentary regarding regulatory aspects. In general, there is growing familiarity with, and acceptance of, 3D printing in clinical use.

Transanal endoscopic surgery with a 3D printed device

BACKGROUND

The aim of this study was to investigate the effectiveness of devices manufactured with 3D printing for performing transanal endoscopic procedures without pneumorectum.

METHODS

Functional devices were designed in the Polytechnic School of Engineering of Gijón from 2016 to 2018 using three-dimensional (3D) solid modelling software (Solid-Works®), that allows customization of the device (diameter and length). The devices were made in acrylonitrile butadiene styrene (ABS) by additive manufacturing using an HP Designjet 3D Printer, with fused deposition modelling (FDM) technology. Tests were carried out on mixed simulators (with viscera) and cadavers with a prototype in the form of an open cylindrical base ellipsoid spindle with two bars. In this paper, we present the information of the first series of patients in which this device has been used to perform a full-thikness endoscopic resection of the rectal wall without pneumorectum. The characteristics of the patients, size, and location of the lesion, the type of anesthesia used, the duration of the procedure, hospital stay, complications, and pathology were analyzed. An endoscopic follow-up was also carried out for at least 2 years.

RESULTS

Seven interventions were carried out in six patients. The lesions were located at a mean distance of 5 cm from the anal verge and an average area of 11.8 cm². Four of the procedures were performed with general anesthesia and 3 with spinal anesthesia. Histopathology examination identified 3 adenomas, 3 pT1 and 1 pT2 adenocarcinomas. All excisions were full thickness. En bloc excision was possible in all cases. In only one case of a benign polyp there was a positive lateral margin. As regards complications, there was one case of postoperative rectal bleeding without the need for transfusions. There were no readmissions and no postoperative mortality.

CONCLUSIONS

An innovative device made with a 3D printer can be used successfully in transanal endoscopic resections of the rectal wall, with spinal anaesthesia and avoiding the need for pneumorectum.

Production of ERCP training model using a 3D printing technique (with video)

BACKGROUND

ERCP training models are very different in terms of anatomical differences, ethical issues, storage problems, realistic tactile sensation, durability and portability. There is no easy way to select an optimized model for ERCP training. If the ERCP training model could be made as a soft silicone model using 3D printing technique, it would have numerous advantages over the models presented so far. The purpose of this study was to develop an optimized ERCP training model using a 3D printing technique and to try to find ways for implementing various practical techniques.

METHODS

All organ parts of this model were fabricated using silicone molding techniques with 3D printing. Especially, various anatomy of the ampulla of Vater and common bile duct (CBD) were creatively designed for different diagnostic and therapeutic procedures. In order to manufacture each of the designed organ parts with silicone, a negative part had to be newly designed to produce the molder. The negative molders were 3D printed and then injection molding was applied to obtain organ parts in silicone material. The eight different types of ampulla and CBD were repeatedly utilized and replaced to the main system as a module-type.

RESULTS

ERCP training silicone model using 3D technique was semi-permanently used to repeat various ERCP procedures. All ERCP procedures using this model could be observed by real-time fluoroscopic examination as well as endoscopic examination simultaneously. Using different ampulla and CBD modules, basic biliary cannulation, difficult cannulation, stone extraction, mechanical lithotripsy, metal stent insertion, plastic stent insertion, and balloon dilation were successfully and repeatedly achieved. Endoscopic sphincterotomy was also performed on a specialized ampulla using a Vienna sausage. After repeat procedures and trainings, all parts of organs including the ampulla and CBD modules were not markedly damaged or deformed.

CONCLUSIONS

We made a specialized ERCP training silicon model with 3D printing technique. This model is durable, relatively cheap and easy to make, and thus allows the users to perform various specialized ERCP techniques, which increases its chances of being a good ERCP training model.

Evaluation and Endoscopic Management of Esophageal Submucosal Tumor

Submucosal tumors (SMTs) originate from tissues that constitute the submucosal layer and muscularis propria, and are covered by normal mucosa. Esophageal SMTs are rare, accounting for <1% of all esophageal tumors. However, the recent widespread use of endoscopy has led to a rapid increase in incidental detection of SMTs in Korea. Esophageal SMTs are benign in ≥90% of cases, but the possibility of malignancies such as gastrointestinal stromal tumor and malignant leiomyosarcoma still exists. Therefore, patients undergo resection in the presence of symptoms or the possibility of a malignant tumor. For resection of esophageal SMTs, surgical resection was the only option available in case of possible malignancy, but minimally invasive surgery by endoscopic resection is becoming more preferable to surgical resection with the development of endoscopic ultrasonography, endoscopic techniques, and other devices.