Peter Halvax

Improving Echo-Guided Procedures Using an Ultrasound-CT Image Fusion System

Introduction. Image fusion between ultrasound (US) and computed tomography (CT) scan or magnetic resonance can increase operator accuracy in targeting liver lesions, particularly when those are undetectable with US alone. We have developed a modular gel to simulate hepatic solid lesions for educational purposes in imaging and minimally invasive ablation techniques. We aimed to assess the impact of image fusion in targeting artificial hepatic lesions during the hands-on part of 2 courses (basic and advanced) in hepatobiliary surgery. Materials and methods. Under US guidance, 10 fake tumors of various sizes were created in the livers of 2 pigs, by percutaneous injection of a biocompatible gel engineered to be hyperdense on CT scanning and barely detectable on US. A CT scan was obtained and a CT-US image fusion was performed using the ACUSON S3000 US system (Siemens Healthcare, Germany). A total of 12 blinded course attendants, were asked in turn to perform a 10-minute liver scan with US alone followed by a 10-minute scan using image fusion. Results. Using US alone, the expert managed to identify all lesions successfully. The true positive rate for course attendants with US alone was 14/36 and 2/24 in the advanced and basic courses, respectively. The total number of false positives identified was 26. With image fusion, the rate of true positives significantly increased to 31/36 (P < .001) in the advanced group and 16/24 in the basic group (P < .001). The total number of false positives, considering all participants, decreased to 4 (P < .001). Conclusions. Image fusion significantly increases accuracy in targeting hepatic lesions and might improve echo-guided procedures.

Gastric supply manipulation to modulate ghrelin production and enhance vascularization to the cardia: proof of the concept in a porcine model.

Introduction. Selective embolization of the left-gastric artery (LGA) reduces levels of ghrelin and achieves significant short-term weight loss. However, embolization of the LGA would prevent the performance of bariatric procedures because the high-risk leakage area (gastroesophageal junction [GEJ]) would be devascularized. Aim. To assess an alternative vascular approach to the modulation of ghrelin levels and generate a blood flow manipulation, consequently increasing the vascular supply to the GEJ. Materials and methods. A total of 6 pigs underwent a laparoscopic clipping of the left gastroepiploic artery. Preoperative and postoperative CT angiographies were performed. Ghrelin levels were assessed perioperatively and then once per week for 3 weeks. Reactive oxygen species (ROS; expressed as ROS/mg of dry weight [DW]), mitochondria respiratory rate, and capillary lactates were assessed before and 1 hour after clipping (T0 and T1) and after 3 weeks of survival (T2), on seromuscular biopsies. A celiac trunk angiography was performed at 3 weeks. Results. Mean (±standard deviation) ghrelin levels were significantly reduced 1 hour after clipping (1902 ± 307.8 pg/mL vs 1084 ± 680.0; P = .04) and at 3 weeks (954.5 ± 473.2 pg/mL; P = .01). Mean ROS levels were statistically significantly decreased at the cardia at T2 when compared with T0 (0.018 ± 0.006 mg/DW vs 0.02957 ± 0.0096 mg/DW; P = .01) and T1 (0.0376 ± 0.008mg/DW; P = .007). Capillary lactates were significantly decreased after 3 weeks, and the mitochondria respiratory rate remained constant over time at the cardia and pylorus, showing significant regional differences. Conclusions. Manipulation of the gastric flow targeting the gastroepiploic arcade induces ghrelin reduction. An endovascular approach is currently under evaluation.

Laparoscopic reconstruction of the diaphragm

The authors report the case of a 63-year-old patient who was polytraumatized in a motor vehicle accident and suffered multiple traumatic injuries. Chest and pelvic fractures as well as left-sided diaphragmatic rupture with associated omentum herniation were diagnosed on CT scan. None of the injuries required urgent surgical intervention. After 10 days supportive therapy, elective laparoscopic reconstruction of the diaphragmatic hernia was performed. The authors discuss the role of laparoscopic diaphragm reconstruction.

Endoluminal surgical triangulation 2.0: A new flexible surgical robot. Preliminary pre-clinical results with colonic submucosal dissection

Complex intraluminal surgical interventions of the gastrointestinal tract are challenging due to the limitation of existing instruments. Our group has developed a master–slave robotic flexible endoscopic platform that provides instrument triangulation in an endoluminal environment.

Mucosal Excision and Suturing for Obesity and GERD

Background. Suture and staple-based endoluminal devices for gastroesophageal reflux disease (GERD) and obesity have failed to demonstrate long-term efficacy. Objective. To demonstrate the feasibility of mucosal excision and full-thickness suture apposition of the excision beds to create sufficient scar tissue formation at the gastroesophageal junction for the intraluminal treatment of GERD or obesity. Design. Survival animal experiments. Patients. Seven mongrel dogs. Interventions. Under general endotracheal anesthesia, a Barostat test was performed on 4 dogs. A mucosal excision device was introduced through the esophagus into the proximal stomach. Two to 4 mucosal excisions were performed on all dogs at or just below the gastroesophageal junction and the mucosal pieces were removed. After hemostasis, an intraluminal suturing instrument was introduced and either 2 or 4 sutures were placed through the excision beds to bring them into apposition. These were tied and the suture strands cut. All dogs were survived for 2 months. End-term endoscopies were performed, and a repeat Barostat procedure was performed on the animals undergoing an antireflux procedure. After euthanasia the stomachs were explanted, examined, photographed, and sectioned for histologic examination. Results. All dogs survived without complication. In the 4 GERD dogs, the Barostat studies demonstrated a significant decrease in gastroesophageal junction compliance. In the 3 dogs undergoing the obesity procedure, the gastric outlet apposition to a 6-mm endoscope was satisfactory with full insufflation and the desired scarring was seen on histologic examination. Conclusion. It is possible to create adequate gastroesophageal junction scarring for the treatment of GERD and obesity. A clinical pilot study will be initiated.

Experimental Evaluation of the Optimal Suture Pattern with a Flexible Endoscopic Suturing System

Background. The ability to perform reliable, secure endoluminal closure of the gastrointestinal tract wall, is a prerequisite to support the progress of the emerging field of endoluminal surgery. Along with advanced clipping systems, flexible endoscopic suturing devices are commercially available. Current systems can replicate traditional surgical suturing patterns in the endoluminal environment. The aim of this study was to evaluate the optimal endoluminal suturing technique using a flexible endoscopic suturing device. Materials and Methods. Procedures were performed on bench-top simulators containing 20 explanted porcine stomachs. A standardized 3-cm full-thickness incision was created on the anterior wall of each stomach using monopolar cautery. The gastrotomy was closed endoscopically using an over-the-scope suturing device (OverStitch, Apollo Endosurgery; Austin, TX). Three different techniques were used: single stitches, figure-of-8 pattern, and running suture. Material consumption and operation time were recorded and bursting pressure measurement of the closure was performed. Results. No statistically significant differences were identified in suturing time. Suturing time (minutes) was slightly shorter with the figure-of-8 technique (41.14 ± 4.6) versus interrupted (45.75 ± 1.1) versus continuous (51.44 ± 10.0), but the difference was not statistically significant. The number of sutures required was greater in the interrupted group. No significant difference was found in the burst pressure (mm Hg): figure-of-8 (45.85 ± 26.2) versus interrupted (30.5 ± 22.89) versus continuous (32.0 ± 26.5). In the figure-of-8 group, 85.5% of cases were leakproof above 30 mm Hg, while in the other groups only 50% of cases were so. Conclusion. A figure-of-8 suturing pattern seems to be the preferable suturing technique with the endoscopic suturing device.

A Newly Designed Enterocutaneous Esophageal Fistula Model in the Pig

Background. Fistulas after esophagectomy are a significant cause of morbidity and mortality. Several endoscopic treatments have been attempted, with varying success. An experimental model that could validate new approaches such as cellular therapies is highly desirable. The aim of this study was to create a chronic esophageal enterocutaneous fistula model in order to study future experimental treatment options. Methods. Eight pigs (six 35-kg young German and two 50-kg adult Yucatan pigs) were used. Through a left and right cervicotomy, under endoscopic view, 1 (group A, n = 6) or 2 (group B, n = 7) plastic catheters were introduced into the esophagus 30 cm from the dental arches bilaterally and left in place for 1 month. Radiologic and endoscopic fistula tract evaluations were performed at postoperative day (POD; 30) and at sacrifice (POD 45). Results. Three fistulas were excluded from the study because of early (POD 5) dislodgment of the catheter, with complete fistula closure. At catheter removal (POD 30), the external orifice was larger in group B (5.2 ± 1.1 mm vs 2.6 ± 0.4 mm) with more severe inflammation (72% vs 33%). At POD 45, the external orifice was closed in all fistulas in group A and in 1/7 in group B. At necropsy, the fistula tract was still present in all animals. Yucatan pigs showed more complex tracts, with a high level of necrosis and substantial fibrotic infiltration. Conclusions. In this article, we show a reproducible, safe, and effective technique to create an esophagocutaneous fistula model in a large experimental animal.