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.

Minimally invasive surgery for posterior gastric stromal tumors.

BACKGROUND: Because involvement is extremely rare, surgery for gastric stromal tumors consists of local excision with clear resection margins. The aim of this study was to report the results of a consecutive series of nine patients with posterior gastric stromal tumors that were excised using a minimally invasive method. METHODS: Patients received a general anesthetic before placement of three laparoscopic ports- a 10-mm (umbilical) port for the telescope and two working ports, a 12-mm port (left upper quadrant) and a 10-mm port (right upper quadrant). Grasping forceps were placed through an anteriorly placed gastrotomy to deliver the tumor through the gastrotomy into the abdominal cavity, thus allowing an endoscopic linear cutter to excise the tumor with a cuff of normal gastric tissue. RESULTS: Nine consecutive patients with a median age of 73 years (range, 47-83) were treated. In seven patients, laparoscopic removal of the tumor was achieved. Two patients required conversion to an open operation because the tumor could not be delivered into the abdominal cavity. The median length of postoperative stay for the seven patients in whom the procedure was completed laparoscopically was 3 days (range, 2-6). CONCLUSIONS: Posterior gastric stromal tumors can be removed safely using this minimally invasive method. Delivery of the tumor through the gastrotomy is essential for success.

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.

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.

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.

A comparison of the strength of knots tied by hand and at laparoscopy.

BACKGROUND: The strength of knots tied at laparoscopy was compared with that of hand-tied knots. STUDY DESIGN: The force needed to undo or break eight types of knots that were tied in fresh postmortem human stomachs was measured. The knotting performance of nylon, polyglactin 910, braided silk, polytetrafluoroethylene, braided polyester fiber, braided polyester suture, polyamide 66, and polydiaxone was also compared. RESULTS: Measurements of knot strength of two to six half hitches (hand tied) showed that four half hitches were necessary to tie a secure nonslipping knot with most monofilament threads (nylon, polytetrafluoroethylene, braided polyester suture, and polyamide 66), while three half hitches were adequate to secure a knot when polyglactin 910, braided polyester fiber, silk, and polydiaxone were used. Additional throws did not increase knot strength once the knot no longer slipped (p = NS). Some commonly tied knots, three half hitches and surgical knots at laparoscopy were weaker than the same hand-tied knots (p < 0.05) but an additional throw increased knot security (p < 0.01). Differences between laparoscopic and hand-tied knot strengths were greater for monofilament than multifilament threads. There was a wider distribution of strengths for laparoscopically tied than hand-tied knots. Four half hitches were the most secure configuration for laparoscopically tied knots and were significantly stronger than three half hitches and surgical knots (p < 0.01). The extracorporeally tied slipknot (Roeder loop) was significantly less secure than four half hitches (p < 0.05). CONCLUSIONS: This study demonstrates that laparoscopically formed knots may be weaker than those tied by hand and shows that improvements in knot strength at laparoscopy can be achieved by choice of optimal knot configuration for different suture materials.