At this point, a new wire was inserted into the abdomen with the 18-Ga needle, low down in the pelvis, under direct endoscopic vision. The wire was grasped with a snare and pulled out through the mouth, scope, and all. This allowed for a “monorail” guidewire, which served the dual purpose of guiding the mesh delivery device into the abdomen when inserted transorally, and also to act as a guide to help locate the gastrotomy in the collapsed stomach (the stomach collapses because of the gastrotomy and the capnoperitoneum).

The mesh was fashioned with 4 full-thickness anchoring sutures (Fig. 15.3) and was placed into the delivery system, which was essentially a modified esophageal stent deployment device (Fig. 15.4). The device was then placed over the guidewire and inserted into the peritoneal cavity by pulling traction on both the oral and percutaneous/pelvic ends of the wire, which serves to make it taught (the “monorail” effect) and which easily allows the device to pass through the gastrotomy into the abdomen. The mesh is then deployed by extruding it from the introducer in a fashion analogous to the deployment of an esophageal stent (Fig. 15.1). The double-channel scope was then reinserted into the peritoneal cavity (after flushing the channels with povidone-iodine solution) to ensure proper mesh deployment. The presence of the indwelling wire allowed for rapid identification of the gastrotomy.

The sutures were identified by color and removed through corresponding stab incisions on the abdominal wall using a looped spinal needle technique [33]. Any needle-sized suture grasper could be used for this part of the procedure. We pre-placed the sutures at the twelve, three, six, and nine o’clock positions around the “defect.” (Of note, we did not create a defect as the aim of the experiment was to place mesh successfully on the abdominal wall without infection). Once the sutures were tied down to the fascia, nitinol tacks (Cook Medical; Fig. 15.5) were endoscopically placed at the four corners of the mesh (Fig. 15.6). These tacks have a double-sided, treble-hook configuration and are placed across the abdominal wall using a 19-gauge delivery needle.

Once the mesh placement was complete, the endoscope was removed, and the gastrotomy was closed. We typically used an endoscopically deployed clip, such as the Padlock-G™ (Aponos Medical, Kingston, NH), but any method of gastrotomy closure can be employed. It is beyond the scope of this chapter to discuss details of gastric closure.

We performed a necropsy at 2 weeks and examined the abdominal wall for gross and microscopic signs of infection; Fig. 15.7 shows an example of abscesses at the tack sites.