Biomedical subjects

Mary A Knipschield

Publications and source records attributed to Mary A Knipschield.

4 recordsLinked to original sources

PubMed2007

Endoscopic full-thickness closure of large gastric perforations by use of tissue anchors.

BACKGROUND: A flexible needle-catheter tissue-anchoring device was developed to accomplish full-thickness tissue apposition of the GI wall. The aim of this study was to identify the performance of this device for repair of large iatrogenic gastric perforations in a porcine model. OBJECTIVES: Six pigs. DESIGN: Short-term survival animal study. SETTINGS: Pigs were studied while they were under general anesthesia. Device performance in differing gastric locations and wall thicknesses was assessed by 2 perforations more than 2 cm in size created for each pig along the greater curvature and the anterior wall. INTERVENTIONS: Each perforation was closed by parallel placement of tissue anchor sets sequentially along the length of the perforation. MAIN OUTCOME MEASUREMENTS: One week follow-up endoscopy and necropsy were performed. RESULTS: Twelve perforations were closed with the 48 tissue anchor sets. All animals survived for 1 week without clinical complications. Follow-up endoscopy and necropsy revealed that all tissue anchors remained with firmly held sutures and sealed perforations. CONCLUSIONS: Full-thickness closure with a new tissue-anchoring device simply and successfully repaired large iatrogenic gastric perforations.

Animals↗

PubMed2006

Pilot study of the porcine uterine horn as an in vivo appendicitis model for development of endoscopic transgastric appendectomy.

BACKGROUND: Iatrogenic inflammation of the porcine uterine horn may serve as an in vivo appendicitis model for the development of endoscopic transgastric appendectomy. OBJECTIVE: Five female pigs. STUDY DESIGN: Animal study. SETTINGS: General anesthesia. MAIN OUTCOME MEASUREMENTS: Anatomical appearance and technical feasibility. INTERVENTIONS: Three pigs were used to identify an injectable material that would inflame the uterine horn, and 2 pigs were used for a pilot appendectomy. Three types of materials were individually injected into the bilateral uterine horns, and the ideal material to inflame the uterine horn was injected into the right uterine horn for the last 2 pigs. After 24 hours, the injected uterine horns of the first 3 pigs were assessed and a pilot appendectomy was performed in the last 2 pigs. RESULTS: Ethanolamine oleate (EO) injected uterine horns demonstrated similarities to the inflamed human appendix. Simulations of the appendectomy were successfully performed by using the EO model. LIMITATIONS: Suboptimal existing tools. CONCLUSIONS: This preliminary study demonstrated the technical feasibility to create a model for acute appendicitis by using the porcine uterine horn and transgastric appendectomy.

Animals↗

PubMed2006

Tissue anchors for transmural gut-wall apposition.

BACKGROUND: With the development of NOTES (natural orifice transluminal endoscopic surgery) and efforts to advance gastric reduction surgery, alternatives for robust tissue apposition apart from suturing and current mucosal clipping devices may be valuable. OBJECTIVES: We attempted to identify functional tissue anchors that could be deployed endoscopically, with the potential to provide transmural tissue apposition. DESIGN: Short-term animal-survival study. PATIENTS: Domestic pigs, under general anesthesia, underwent open laparotomy, gastrotomy, and manual placement of prototype tissue anchors. INTERVENTIONS: Four tissue-anchor designs were evaluated (T bar, T bar with mesh bolster, star, basket). Full-thickness gastric plications were manually created in the body and the antrum via laparotomy and were secured with sets of paired anchors, also placed manually via a gastrotomy. In 1 test animal, a pilot gastric reduction was created by forming 2 rows of 4 anchor sets on the anterior and posterior walls to create a tubelike gastric lumen. MAIN OUTCOME MEASUREMENTS: Follow-up endoscopy was performed at 2, 4, and 9 weeks to visually assess the intraluminal appearance of the plications, followed by necropsy and histologic study. RESULTS: There was an overall attrition of the number of anchor sets. At 2 weeks, the T-bar anchors were first to disappear, and the mesh and the star designs began to pull through the gastric folds. At 4 weeks, there was flattening of the plications that involved 6 pairs of mesh anchors. By 9 weeks, 3 pairs of mesh anchors were lost and 3 pairs were associated with flattened folds. At the time of euthanasia, at 4 or 9 weeks, the number of retained anchors associated with intact plications for each group were as follows: T bar, 6 of 9 pairs (67%); mesh, 12 of 18 pairs (67%); basket, 14 of 18 pairs (78%); and star, 2 of 9 pairs (22%). There were no gastric adhesions and no evidence for any inflammatory changes surrounding the stomachs. The tallest plications involved the basket anchors. The basket-anchored plications contained apposed muscularis propria, with serosal fusion evident. The folds from the other anchor types were formed of mucosa and submucosa with or without superficial muscularis propria. CONCLUSIONS: The results of this experience are encouraging. The basket tissue anchors appear most promising. These findings suggest that further development of tissue anchors deployed via flexible catheter-based devices may have clinical value for transmural tissue apposition.

Animals↗

PubMed2003

Prospective controlled assessment of variable stiffness enteroscopy.

BACKGROUND: Push enteroscopy is a well-established technique for evaluation of the small intestine. However, looping of the enteroscope within the stomach limits depth of insertion. Stiffening overtubes that minimize gastric looping are tolerated marginally by patients and disliked by endoscopists. A variable stiffness instrument has the potential to eliminate the need for an overtube while still minimizing gastric looping. The performance of a prototype variable stiffness enteroscope was compared prospectively with that of a conventional push enteroscope with and without use of an overtube. METHODS: Consecutive patients undergoing enteroscopy were randomized to have the procedure with a variable stiffness instrument, a conventional instrument with overtube, or a conventional instrument without overtube. Depth of insertion distal to the ligament of Treitz was determined by plain abdominal radiography. OBSERVATIONS: In total, 67 patients were randomized to variable stiffness enteroscopy (25 patients), enteroscopy with overtube (23 patients), and enteroscopy without overtube (19 patients). Median depth of insertion distal to the ligament of Treitz, respectively, for each group, was 89 cm, 68 cm and 41 cm (p = 0.03). In multivariate analysis, variable stiffness instrument use was predictive of intubation to 65 cm distal to the ligament of Treitz (odds ratio 5.53: 95% CI [1.25, 31.25] vs. no overtube, and odds ratio 2.50: 95% CI [0.63, 11.1] vs. overtube). Procedure duration and overall patient tolerance did not differ significantly among the 3 groups, although more patients in the overtube group required additional sedation than patients in the variable stiffness group (p = 0.03). Both endoscopists' (r = 0.34) and nurses' (r = 0.36) estimates of patient discomfort during the procedure correlated poorly with patient tolerance. CONCLUSIONS: A variable stiffness push enteroscope enhances insertion depth compared with the conventional instrument with or without overtube. Further studies are required to determine whether this improved performance increases diagnostic yield.

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