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Biomedical subjects

C P Swain

Publications and source records attributed to C P Swain.

At least 19 recordsLinked to original sources
PubMed2002

Endoscopic vertical band gastroplasty with an endoscopic sewing machine.

BACKGROUND: Vertical band gastroplasty is an accepted surgical operation for the treatment of obesity. It is performed by means of an open technique. This is a description of a new endoscopic technique for gastroplasty. METHODS: An endoscopic sewing machine was mounted on a flexible upper endoscope. On a postmortem specimen of porcine gastroesophageal tissue an area of the stomach, about 8-cm long and 4-cm wide, extending from and in line with the esophagus, was marked. A flexible plastic ring about 3 cm in diameter was sutured to the stomach along the lesser curvature at 8 cm from the gastroesophageal junction with an endoscopic sewing machine. Vertical gastroplasty was accomplished by suturing together the anterior and posterior walls of the stomach with the endoscopic sewing machine. Hence, a gastroplasty was fashioned as an 8-cm-long tube along the lesser curvature of the stomach extending from the gastroesophageal junction to the outlet ring. OBSERVATIONS: An endoscopic gastroplasty for obesity was successfully performed by using an endoscopic sewing machine on a postmortem specimen of porcine stomach. CONCLUSION: The technical feasibility of endoscopic vertical ring gastroplasty should be tested in a live animal model. This will serve as the next phase in the development of this interventional endoscopic technique, which has potential for clinical applicability.

Animals↗
PubMed2001

Electrical stimulation for propelling endoscopes.

BACKGROUND: Methods are needed for propulsion of endoscopes and wireless video capsules along the small intestine. This work aims to test the hypothesis that electrical stimulation could propel an endoscope by stimulating muscular contraction. METHODS: Prototype acrylic ovoid-shaped devices were constructed with 2 stainless steel electrodes mounted on the tapered section. Five devices 15 to 23 mm diameter with a taper of 28 degrees to 40 degrees (included angle) were tested. When these devices were in contact with the bowel wall, electrostimulation was applied causing circular muscle contraction, which when applied to the taper of the ovoid resulted in forward propulsion of the device. The method does not induce peristalsis but works by stimulating local contraction. The device was tested in the small intestine and esophagus of anesthetized pigs. RESULTS: Electrostimulation caused the ovoid to advance rapidly (6 mm/sec) up and down the esophagus by inducing circular esophageal muscle contraction. When stimulated at 15 Hz with 30-ms pulses, the threshold for movement in the small intestine was 12 mA; at 20 mA the device moved reliably in either direction in the small intestine at speeds of up to 4.5 mm/sec and negotiated tight curves. CONCLUSION: Electrostimulation can move endoscopes in the small intestine.

Animals↗
PubMed2000

Mechanical endoscopic methods of haemostasis for bleeding peptic ulcers: a review.

Re-bleeding following endoscopic therapy for gastrointestinal bleeding remains common probably because injection and thermal methods for treating bleeding are of limited efficacy, especially in the presence of a large bleeding artery. This chapter reviews mechanical methods of endoscopic haemostasis. The design of clips, which can be delivered through flexible endoscopes, is reviewed with experimental and clinical data of their efficacy. The need for improvements in clip design is stressed. Experimental studies and preliminary clinical data where available on a variety of other mechanical methods of haemostasis are presented, including band ligation, endoloops, sewing machines, stapling machines, ulcer clamps, corkscrews, balloon tamponade and ferromagnetic tamponade. New, less invasive, surgical methods which might have a place in ulcer haemostasis, including transgastric endoluminal surgery and flexible endoscopic ulcer excision with wound closure, are discussed. Mechanical methods offer the best prospect for improvements in security of endoscopic haemostasis for bleeding peptic ulcer. More development is required if the results are to improve.

Balloon Occlusion↗
PubMed2000

The measurement of forces exerted during colonoscopy.

BACKGROUND: The widely varying forces used at colonoscopy have not been measured. An electronic device was designed to measure the forces exerted by the clinician on the endoscope during colonoscopy. METHODS: The device featured a handle designed in the shape of a hinged split cylinder that could be locked around the endoscope but readily moved up and down the insertion tube as the colonoscopy proceeded. This cylinder contained strain-gauges arranged so that the forces transmitted could be accurately measured. The device recorded the torque forces in addition to the push and pull forces exerted during diagnostic colonoscopy. RESULTS: In a series of 21 colonoscopies in 20 patients: peak pushing force = 4.4 kg, pulling force = -1.8 kg, anti-clockwise torque = 1.0 Newton meters, clockwise torque = 0.8 Newton meters. Percentage time force greater than 1 kg = 5%. Peak anal insertion force = 1.8 kg. CONCLUSIONS: These measurements represent the first accurate measurements of the forces exerted during colonoscopy. Reducing the force during colonoscopy is likely to diminish pain and reduce the risk of perforation. A knowledge of these forces may also help with the design of new instruments and models for teaching or research.

Adult↗
PubMed1999

Electrophysical factors influencing endoscopic sphincterotomy.

BACKGROUND: Analog computer techniques were used to measure electrosurgical power during sphincterotomy in experimental models and patients. METHODS: Total energy and transient changes in power were measured during sphincterotomy of bile ducts in the livers of pigs, ampullae of humans post mortem, and during clinical sphincterotomy. The effect of waveform on hemostasis was studied in experiments on canine mesenteric arteries. RESULTS: Electrosurgical waveforms (CUT, COAG, BLEND) were measured. Halving wire contact length halved energy needed to initiate cutting. The CUT waveform rarely initiated cutting at lower power settings than the BLEND waveform. With CUT, BLEND, and COAG waveforms, approximately the same energy initiated cutting. Efficiency of cutting increased linearly with power. The COAG waveform required higher power settings than BLEND or CUT to initiate cutting (p < 0.05). Force and wire diameter influenced cutting. BLEND was more effectively hemostatic than CUT (p < 0.05). COAG was significantly more hemostatic than BLEND and CUT. Cutting efficiency during clinical sphincterotomy was poor. CONCLUSIONS: This work has practical implications. Shortening wire contact length was effective in starting a cut at suboptimal settings, whereas changing from BLEND to CUT made little difference. Increasing power setting may help if cutting does not start. BLEND stops bleeding better than CUT. COAG stops bleeding better than BLEND but cuts poorly. Cutting during clinical sphincterotomy is inefficient and can be improved.

Analog-Digital Conversion↗
PubMed1999

Development and application of endoloops for the treatment of bleeding esophageal varices.

BACKGROUND: Endoloops are detachable nylon snares. The aims of this study were to develop an endoscopic method for repeated delivery of endoloops to arrest variceal bleeding, to compare efficacy of endoloop hemostasis with injection and band ligation in experimental models of bleeding, and to test the reliability and safety of endoloops in a pilot study in patients with varices. METHODS: Technical modifications including ridged endcaps and alterations in angulation of endoloops were developed to speed delivery and improve efficacy. Hemostatic efficacy of endoloops was compared with sclerotherapy and band ligation in animal studies before studies in patients. RESULTS: Modified endcap and endoloops allowed repeated applications without withdrawal of the endoscope. Right-angled endoloops ensnared more (p < 0.0001) gastric tissue and were more reliable (p < 0.05) than straight endoloops. Injection therapy and prestretched bands appeared ineffective, whereas band ligation was only effective on vessels up to 2 mm in diameter. Only endoloops achieved hemostasis on vessels of 3 to 5 mm (p < 0.05). No significant complications occurred using endoloops in animal (esophagus n = 20, stomach n = 20) or human (n = 11) studies. CONCLUSIONS: Endcap and endoloop modifications simplified repeated application to varices. Endoloops were more effective than injection or band ligation in experimental hemostasis and appeared safe and effective in patients.

Animals↗
PubMed1999

Endoscopic suturing.

Suturing at flexible endoscopy might extend the range of less invasive surgical procedures that can be performed without incision. The development of sewing machines that can place single and multiple stitches in the gastrointestinal tract is outlined. Methods of tying knots and cutting thread at flexible endoscopy have also been developed. The results of some applications, including the treatment of gastro-oesophageal reflux disease, the closure of perforations, haemostasis, and the attachment of feeding tubes and radiotelemetry capsules to tissue using endoscopic suturing, are described.

Endoscopy, Digestive System↗
PubMed1999

An ambulant porcine model of acid reflux used to evaluate endoscopic gastroplasty.

BACKGROUND: There is a lack of suitable models for testing of therapeutic procedures for gastro-oesophageal reflux disease. Endoscopic sewing methods might allow the development of a new less invasive surgical approach to treatment of gastrointestinal disorders. AIMS: To develop an animal model of gastro-oesophageal reflux for testing the efficacy of a new antireflux procedure, endoscopic gastroplasty, performed at flexible endoscopy without laparotomy or laparoscopy. METHODS: At endoscopy a pH sensitive radiotelemetry capsule was sewn to the oesophageal wall, 5 cm above the lower oesophageal sphincter, in six large white pigs. Ambulant pH recordings (48-96 hours; total 447 hours) were obtained. The median distal oesophageal pH was 6.8 (range 6.4-7.3); pH was less than 4 for 9.3% of the time. After one week, endoscopic gastroplasty was performed by placing sutures below the gastro-oesophageal junction, forming a neo-oesophagus of 1-2 cm in length. Postoperative manometry and pH recordings (24-96 hours; total 344 hours) were carried out. RESULTS: Following gastroplasty, the median sphincter pressure increased significantly from 3 to 6 mm Hg and in length from 3 to 3.75 cm. The median time pH was less than 4 decreased significantly from 9.3% to 0.2%. CONCLUSIONS: These are the first long term measurements of oesophageal pH in ambulant pigs. The finding of spontaneous reflux suggested a model for studying treatments of reflux. Endoscopic gastroplasty increased sphincter pressure and length and decreased acid reflux.

Animals↗
PubMed1999

The role of enteroscopy in clinical practice.

Enteroscopy does not yet carry the conviction that physicians are used to with gastroscopy and colonoscopy. The examination is never complete. The distance of small bowel examined in any individual examination is unknown. Although some therapeutic maneuvers are possible, the further the endoscope is into the small bowel the more difficult it becomes to pass and control the instruments. There is more room for improvement in enteroscopy than in almost any other area of gastrointestinal endoscopy. Nonetheless, there have been real gains for patients with difficult gastrointestinal bleeding and small bowel pathology with advances in diagnostic and therapeutic ability with enteroscopes achieved by a combination of relatively minor technologic changes and some clinical enthusiasm.

Biopsy↗
PubMed1999

Technical advances and experimental devices for enteroscopy.

Enteroscopy remains the procedure in the gastrointestinal tract that is most inaccessible to endoscopy, and technical limitations severely impair the ability to advance and examine the small bowel reliably or completely. Push-type enteroscopy not only suffers limitations owing to looping in the stomach, but is intrinsically associated with increasing loss of transmission of force to the tip and consequent failure of advancement. Development is this area has been slow, partly owing to the limited clinical need compared with upper gastrointestinal endoscopy, and colonoscopy and consequent financial limitations imposed on further development. Practical and useful technical advances have been made, especially in push-type as well as sonde-type enteroscopy. These are reviewed briefly and are covered in other articles elsewhere in this issue.

Animals↗
PubMed1998

Device for measuring the forces exerted on the shaft of an endoscope during colonoscopy.

Colonoscopy involves advancing a flexible endoscope into and along the entire length of the colon. The procedure can be painful and carries the risk of perforating the organ, yet very little is known of the forces involved. A device to measure the forces exerted on the endoscope during colonoscopy is described. The device features a handle designed in the shape of a hinged split cylinder that locks around the endoscope, gripping it tightly. The handle has two parts, an inner part that grips the endoscope, and an outer part that is gripped by the endoscopist. The two parts are joined together by members that transmit the forces through to the endoscope. One of the members incorporates strain gauges that measure the torque applied to the endoscope, as well as the push and pull forces. The handle can easily be unlocked and moved along the endoscope as the colonoscopy proceeds. The device is used to measure the forces applied to the endoscope during 11 routine colonoscopies, and summary results are presented. These are believed to be the first accurate measurements of the forces exerted during colonoscopy.

Colonoscopes↗
PubMed1998

A randomised controlled comparison of injection, thermal, and mechanical endoscopic methods of haemostasis on mesenteric vessels.

BACKGROUND AND AIMS: A randomised controlled comparison of haemostatic efficacy of mechanical, injection, and thermal methods of haemostasis was undertaken using canine mesenteric vessels to test the hypothesis that mechanical methods of haemostasis are more effective in controlling haemorrhage than injection or thermal methods. The diameter of arteries in human bleeding ulcers measures up to 3.45 mm; mesenteric vessels up to 5 mm were therefore studied. METHODS: Mesenteric vessels were randomised to treatment with injection sclerotherapy (adrenaline and ethanolamine), bipolar diathermy, or mechanical methods (band, clips, sewing machine, endoloops). The vessels were severed and haemostasis recorded. RESULTS: Injection sclerotherapy and clips failed to stop bleeding from vessels of 1 mm (n = 20) and 2 mm (n = 20). Bipolar diathermy was effective on 8/10 vessels of 2 mm but failed on 3 mm vessels (n = 5). Unstretched elastic bands succeeded on 13/15 vessels of 2 mm but on only 3/10 vessels of 3 mm. The sewing machine achieved haemostasis on 8/10 vessels of 4 mm but failed on 5 mm vessels (n = 5); endoloops were effective on all 5 mm vessels (n = 5). CONCLUSIONS: Only mechanical methods were effective on vessels greater than 2 mm in diameter. Some mechanical methods (banding and clips) were less effective than expected and need modification. Thermal and (effective) mechanical methods were significantly (p < 0.01) more effective than injection sclerotherapy. The most effective mechanical methods were significantly more effective (p < 0.01) than thermal or injection on vessels greater than 2 mm.

Animals↗
PubMed1997

What endoscopic accessories do we really need?

This article is a speculative essay that reviews the current limitations of existing flexible endoscopic accessories. Suggestions are offered on future developments that may change endoscopic practice as it adopts an increasingly therapeutic role. There may be a potential for development in flexible endoscopic surgical techniques that will be comparable to those seen in rigid laparoscopic surgery. Low and high technology solutions are considered. Invention, common sense, and engineering efforts are needed to take flexible endoscopic surgery to a higher level of functional efficacy.

Endoscopy, Digestive System↗