Biomedical subjects

Tim Mills

Publications and source records attributed to Tim Mills.

7 recordsLinked to original sources

PubMed2006

Colon cleaning during colonoscopy: a new mechanical cleaning device tested in a porcine model.

BACKGROUND: Poor colon cleaning frequently impairs colonoscopy. The aim of the study was to develop a method of cleaning the colon during colonoscopy. METHODS: A soft-tipped catheter with a water jet spray at its tip was designed to break up and propel stool contents in the direction of the anus. Stool contents were collected in a container attached to an endoscopy trolley. OBSERVATIONS: In bench tests, colon models filled with porridge were rapidly cleaned. Unprepared colons (n = 15) of anesthetized pigs were cleared in a few minutes by using this device at colonoscopy, by advancing the catheter under direct vision into concretions, which were rapidly broken down. There was minimal trauma to mucosa in these survival studies. CONCLUSIONS: A colon cleaning method for use at colonoscopy was highly effective in cleaning colon models and in unprepared pig colon. This device may have a role in cleaning the colon in unprepared or poorly prepared patients.

Animals↗

PubMed2006

Endoscopic full-thickness resection: circumferential cutting method.

BACKGROUND: Endoscopic full-thickness resection (EFTR) at flexible endoscopy might allow less-invasive removal of more deeply penetrating cancers that have not spread to the serosal surface and more complete histologic examination of the excised tissue. OBJECTIVE: A method for closure of full-thickness defects in the stomach wall would be valuable for other endosurgical applications. SETTING: A method that uses an end cap and band-ligation without prior injection of saline solution to perform EFTR gave good results and was safe in pig studies. There is a size limitation of cancers that can be resected en bloc when using this method. The depth of resection was also variable. DESIGN AND INTERVENTIONS: EFTR was achieved by circumferential cutting with a sphincterotome and a snare. A prototype bidirectional cutter was tested. Sutured closure was accomplished by using a sheathed needle, a metal tag, and a thread at the tip, passed through a 2.8-mm accessory channel. Knot-tying devices secured the sutured defect. MAIN OUTCOME MEASUREMENTS: EFTR was studied in non-survival (n = 4) and survival (n = 8) experiments in pigs. RESULTS: Full-thickness specimens were resected from the gastric wall (100%, 12/12), and the defects were closed by using sewing and knot-tying devices (100%, 12/12). LIMITATIONS: A healing ulcer at the suturing site was evident at follow-up endoscopy in the survival experiments. Bleeding, which was stopped by suturing, occurred in 1 pig (8.3%, 1/12). All pigs survived these experiments without complications (100%, 8/8). CONCLUSIONS: Circumferential EFTR was feasible and appeared safe in survival experiments. This method might allow larger and deeper resection of tumors in the gastric wall.

Animals↗

PubMed2006

The Cath-Cam: a new concept in colonoscopy.

BACKGROUND: Guidewires and catheters exert less force on the gut wall than an endoscope. OBJECTIVE: To develop a guidewire-assisted device for colonoscopy. METHODS: A light-weight flexible catheter illuminated with light-emitting diodes was designed to carry an ultraslim high-resolution videoendoscope of 3 mm. Tip bend stiffness was 5 times less than a colonoscope. Hinged guidewires were passed, folded, through the accessory channel. A loop could be rapidly formed to explore the lumen. RESULTS: The catheter followed curves of excised pig colon and exerted significantly less force on the colon wall than a colonoscope (mean 1.6 +/- 0.23 N vs 3.0 +/- 0.37 N, P < .05; bend-radius, 80 mm). Survival studies in pigs showed that the guidewire loop could be advanced under visual control and the Cath-Cam could be advanced by using much less force than the colonoscope. CONCLUSIONS: A catheter-based colonoscope with a miniature video imager reduced the force required for successful colonoscopy in pigs.

Animals↗

PubMed2005

Endoscopic full-thickness resection with sutured closure in a porcine model.

BACKGROUND: Some early gastric cancers might be advantageously staged and treated by full-thickness resection if secure methods for closing the defect were available. The aim of this study was to test the feasibility of full-thickness gastric resection. METHODS: Full-thickness gastric resections were performed by using a ligating device without submucosal injection in survival studies in pigs (n = 8). The defects were closed by using new methods for suturing, locking, and cutting thread through a 2.8-mm accessory channel. Stitches (n = 2-4) were placed close to the target area before resection. OBSERVATIONS: Full-thickness resections (n = 8) were performed. The pigs survived without incident for 21 to 28 days. Healing of the suture site was evident at follow-up endoscopy. Suture sites were water tight. The pull-out force with stitches by using this new sewing method was significantly higher than with endoscopic clips (20.3 N +/- 0.94 vs. 2.2 N +/- 0.42, p < 0.05). CONCLUSIONS: Endoscopic full-thickness resection with sutured defect closure was feasible and appeared safe in these survival experiments.

Animals↗

PubMed2004

Transgastric gastropexy and hiatal hernia repair for GERD under EUS control: a porcine model.

BACKGROUND: Endoluminal operations for gastroesophageal reflux currently are limited by the inability to visualize and manipulate structures outside the wall of the gut. This may be possible by using EUS. The aims of this study were the following: to define the EUS anatomy of structures outside the gut that influence reflux, to place stitches in the median arcuate ligament, to perform posterior gastropexy, and to test the feasibility of crural repair under EUS control in pigs. METHODS: In survival experiments in 22 pigs, by using a linear-array echoendoscope, the median arcuate ligament and part of the right crus were identified and punctured with a needle, which served as a carrier for a tag and thread. These were anchored into the muscle. An endoscopic sewing device was used, allowing stitches to be placed through a 2.8-mm accessory channel to any predetermined depth. New methods allowed knot tying and thread cutting through the 2.8-mm channel of the echoendoscope. RESULTS: Stitches were placed through the gastric wall into the median arcuate ligament, and one stitch was placed just beyond the wall of the lower esophageal sphincter. The stitches were tied together and locked against the gastric wall. Median lower esophageal sphincter pressure, determined manometrically, was 11 mm Hg before surgery and 21 mm Hg after stitch placement (p=0.0002). The length of the lower esophageal sphincter increased from a median of 2.8 cm before the procedure to 3.5 cm after the procedure. At the postmortem, the median force required to pull the tags out of the median arcuate ligament was 2.8 kg. CONCLUSIONS: This study demonstrates that transgastric gastroesophageal reflux surgery, by using stitching under EUS control, can significantly increase lower esophageal sphincter pressure in pigs.

Animals↗

PubMed2003

Transluminal endosurgery: single lumen access anastomotic device for flexible endoscopy.

BACKGROUND: Forming anastomoses between two hollow organs at flexible endoscopy might reduce the need for surgery for obstructing malignancy. Current methods require access to both lumens. The aim of this work was to develop methods of forming an anastomosis at flexible endoscopy, such as a gastrojejunostomy or cholecystoduodenostomy, when access to only one lumen is feasible. METHODS: A modified needle was passed through a large-channel echoendoscope from the accessible lumen into the target hollow organ. An anastomotic device was formed by using two 7F catheter segments, which were pushed over a guidewire into the target, the less accessible lumen. When released, by withdrawing the guidewire, the catheters formed a cross shape and created an anastomosis when compressed against a plate from the accessible side. OBSERVATIONS: These devices were tested in live animal experiments. With an echoendoscope in the stomach, it was repeatedly possible to place needles, threaded tags, and guidewires into the small intestine and gallbladder. In 4 to 7 days, anastomoses were formed in 16 pigs between the small intestine and the stomach, and between the gallbladder and the stomach. The initial diameter of the anastomoses ranged from 3 to 9 mm. No complication occurred. CONCLUSIONS: It is feasible to form anastomoses at flexible endoscopy when access is limited to a single side.

Anastomosis, Surgical↗

PubMed2003

Bard EndoCinch: the device, the technique, and pre-clinical studies.

There is, of course, room for improvement. More work is needed to make endoscopic suturing easier, quicker and more reliable. The single most important next goal is to construct a device, which can place multiple stitches without the need to remove the endoscope between each stitch. Devices, which can place two stitches in one go, would be a start. The development of double stitch and multiple stitch devices has been described earlier. The authors are pleased to see two alternative commercial endoscopic sewing devices appear at the last DDW which place two stitches without needing to withdraw the endoscopes--they use a double needle method.

Anastomosis, Surgical↗