High-frequency US probe sonography-assisted endoscopic mucosal resection

A Novel Endoscopic Bariatric Procedure: Results of an Experimental Study

BACKGROUND

Surgical treatment of obesity is characterized by both early and late complications, and thus, there is a need to develop safe and non-invasive techniques. Ghrelin is an orexigenic hormone produced by the fundus of the stomach, which may represent a novel target for obesity management. Unfortunately, numerous attempts to alter ghrelin levels have failed to present significant clinical results. We describe a novel procedure that involves modifying arterial blood flow to the gastric fundus for limiting plasma ghrelin levels.

METHODS

A gastroscope was advanced into the gastric fundus of 13 healthy Yorkshire swine, and the fundus was clipped under direct visualization to restrict left gastric artery blood flow. Body weights and ghrelin levels were recorded before and once a week for 4 weeks after the procedure.

RESULTS

Compared to controls, gastroscopic clipping of the fundus decreased plasma ghrelin levels and prevented further weight gain in the 4 weeks of follow-up. Immunohistochemistry and histomorphometry revealed reduced numbers of ghrelin-positive cells in the fundus of experimental animals. We also observed thrombosis in submucosal arteries and submucosal fibrosis. Histological studies demonstrated minimal gastric mucosal injury.

CONCLUSION

Gastroscopic clipping of the fundus in an experimental porcine model resulted in sustained weight loss and a reduction in plasma ghrelin levels at 1 month post-procedure, with no adverse events. Further experimental studies in human patients are needed to examine the clinical utility of this procedure and to optimize a technique, which can facilitate adequate weight loss while minimizing the risk of mucosal injury.

Early gastric cancer and dysplasia

Since the concept of early gastric cancer was first described in Japan in 1962, its treatment has evolved from curative surgical resection to endoscopic resection, initially with polypectomy to more recently with endoscopic submucosal dissection. As worldwide experience with these endoscopic techniques evolve and gain acceptance, studies have confirmed its comparable effectiveness with historical surgical outcomes in carefully selected patients. The criteria for endoscopic resection have expanded to offer more patients improved quality of life, avoiding the morbidity and mortality associated with surgery. This article summarizes the evolutional role of endoscopic and surgical therapy in early gastric cancer.

State of the art on endoscopic mucosal resection and endoscopic submucosal dissection

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) provide new alternatives for minimally invasive treatment of superficial gastrointestinal malignancies. Evidence suggests that these techniques can be performed safely and have comparable outcomes to surgery with less morbidity and better quality of life due to their tissue-sparing nature when compared with conventional surgery. Although the techniques and accessories have become standardized, there is room for improvement, and further research and development are required. Current challenges facing American gastroenterologists or endoscopic surgeons include access to training and lack of appropriate reimbursement for these heavy-weighted and technically demanding procedures. Nevertheless, EMR and ESD are here to stay and are only the first steps toward true radical endoluminal resection of GI malignancies.

Study of full-thickness endoluminal segmental resection of colon in a porcine colon model (with videos)

BACKGROUND

Entrapment injury of the adjacent bowel is frequently encountered during full-thickness endoluminal colon suction-resection.

OBJECTIVE

Our purpose was to develop a technique that can create a full-thickness resection of the colon without the risk of entrapment injury to adjacent viscera.

DESIGN

Pilot study.

SETTING

University medical center.

PATIENTS

Five pigs.

INTERVENTIONS

Traction-resection of the colon was created by using a grasping forceps to pull the colon into a band ligator loaded on a double-channel endoscope, followed by the application of a band, and subsequent snare resection (n = 14). Suction-resection of the colon was created by using a double-channel endoscope loaded with a band ligator (n = 12) and a single-channel endoscope with a band ligator (n = 6).

MAIN OUTCOME MEASUREMENTS

Number of full-thickness colon resections, frequency of the adjacent bowel and mesenteric injury, and the size of the resections were measured.

RESULTS

The suction-resection technique resulted in significant injury to adjacent viscera compared with the traction-resection technique (56% vs 0%, P = .0013). The traction-resection method resulted in a significantly larger resection compared with the suction-resection method (mean +/- SEM: 2.91 +/- 0.3 cm vs 2.1 +/- 0.1 cm, P = .024). A double-channel endoscope suction-resection method resulted in a significantly larger resection compared with a single channel suction-resection technique (mean +/- SEM: 2.1 +/- 0.1 cm vs 0.91 +/- 0.2 cm, P = .0022).

LIMITATIONS

None.

CONCLUSIONS

The traction-resection technique is safer than the suction-resection method in removing larger specimens of the colon. In addition, the traction-resection technique reduces the risk of injury of the mesentery or adjacent small intestine.

Endoscopic mucosal resection: treatment of neoplasia

Techniques of endoscopic mucosal resection (EMR) can dramatically improve the ability to diagnose and treat superficial lesions in the gastrointestinal (GI) tract. Early cancers, submucosal tumors, and sessile polyps can be safely and completely removed in a single procedure, with long-term outcome results comparable to surgery. This is accomplished with a minimum cost, morbidity, and mortality and with little or no impact on the quality of life of patients. This article provides an overview of the techniques, indications, and outcomes of EMR in the management of GI malignancy.

A prospective evaluation of high-magnification chromoscopic colonoscopy in predicting completeness of EMR

BACKGROUND

EMR is used to treat flat and sessile lesions in the colon. The aim of this study was to prospectively assess the efficacy of high-magnification chromoscopic colonoscopy in predicting complete resection margins after EMR.

METHODS

A total of 1250 patients underwent colonoscopy by using a magnifying colonoscope. Chromoscopy with indigo carmine and crystal violet dye solutions was used to assess mucosal pit patterns. EMR was performed by using the saline solution inject-and-cut technique. After EMR, resection margins were inspected by using high magnification, and completeness of excision was predicted from the surface pit pattern. This was compared with completeness of excision as determined histopathologically.

RESULTS

A total of 684 lesions were treated by EMR (62 piecemeal) in 602 patients. The sensitivity of high-magnification chromoscopic colonoscopy for predicting remnant tissue in the lateral margins and the deep margins were, respectively, 79% and 80%. Specificity for both margins was 97%. The overall accuracy of high-magnification chromoscopic colonoscopy in predicting incomplete resection after EMR in the lateral axis and the deep axis was, respectively, 93% and 95%, where the true respective fractions of incomplete resections were 17% and 10%. Of the single en bloc EMRs performed, 77 (12%) had histopathologic evidence of incomplete resection in either axis, compared with 60 (97%) of the 62 piecemeal resections. Piecemeal resection was more likely to result in incomplete resection compared with en bloc EMR (p < 0.001). Complete resection by EMR was more likely if the lesion was sessile instead of flat (p < 0.001).

CONCLUSIONS

High-magnification chromoscopic colonoscopy as an in vivo modality for prediction of remnant tissue after EMR has a high overall accuracy, but further studies assessing long-term outcome and cost-effectiveness compared with conventional colonoscopic techniques are required.

ENDOSCOPIC ULTRASOUND INSTRUMENTATION, APPLICATIONS IN HUMANS, AND POTENTIAL VETERINARY APPLICATIONS

Endoluminal scanning under endoscopic guidance, or endoscopic ultrasonography (EUS), has become the most significant advance for imaging the gastrointestinal (GI) tract wall and contiguous organs in the past 20 years. It was originally designed to overcome the limitations in humans to imaging the abdominal organs transabdominally, such as large penetration depths and GI air. This imaging modality provides detailed images of pathological processes both within and outside of the GI wall since a high-frequency transducer can be brought into close proximity with the target regions. It has found most success in humans for the staging of lung, gastric, and esophageal cancer, the detection of both lymphatic and hepatic metastases, and diagnosis of pancreatitis and pancreatic cancer, as well as achieving an important role in interventional and therapeutic procedures. The EUS examination can be performed to examine both the thorax and abdomen in animals when both conventional transthoracic or transabdominal ultrasound are inadequate due to intervening air, bone, large penetration depths, or obesity. The echoendoscope is similar to a conventional endoscope but has an ultrasound transducer at its tip. Both radial and linear multifrequency scanners are available. Linear scanners allow fine-needle aspiration (FNA) of the bowel wall or extraluminal structures. Transducer coupling is either by direct mucosal contact or by inflation of a water-filled balloon surrounding the transducer. Current thoracic applications for EUS in veterinary medicine include examination of the mediastinum, bronchial lymph nodes, esophagus, and pulmonary lesions as well as FNA of pulmonary masses. Abdominal applications include examination of both pancreatic limbs and the liver, including portosystemic shunts, detection of lymphadenomegaly, and examination of the gastric wall, duodenum, and jejunum. Other potential applications in dogs and cats include tumor staging and intrapelvic ultrasound.