Small Animal Surgical Emergencies. Группа авторов

40 for lateral thoracotomy approach). In addition, in cases of suspected esophageal perforation, most authors recommend surgical exposure and repair of the defect [1, 4, 8]. Experimental perforations less than 12 mm in diameter may seal [13] and a nil by mouth conservative approach has been advocated; however, these data relate to healthy esophagi perforated by a probe of known diameter, which was immediately retrieved (as opposed to a foreign body resting in situ). For these reasons, the author urges circumspection with respect to these findings, particularly in cases of thoracic esophageal perforation.

A left‐sided intercostal thoracotomy is preferred for access to the caudal thoracic esophagus, the exact intercostal space being determined by the location of the foreign body on preoperative imaging (Case Report 4.1). Objects in the esophagus overlying the heart base may be approached by left‐ or right‐sided intercostal thoracotomy; the author prefers the left‐sided approach. Rib resection techniques are described but are generally unnecessary. Laparotomy sponges are used to pack off the lung lobes and isolate the esophagus in case of spillage of luminal fluid. The esophagus is elevated using stay sutures (Figure 4.10) or by passing umbilical tape around the esophagus. Care is taken to avoid damage to the dorsal and ventral vagal trunks. Suction of esophageal luminal fluid is undertaken by mouth or immediately after incision of the esophagus. A longitudinal incision is performed, avoiding areas of significant inflammation. The proposed incision site may be constrained by the aortic arch in the region of the heart base, and esophageal incision directly over the foreign body may not be possible. The esophageal lumen is accessed and the foreign body is carefully disengaged from the mucosa and manipulated out of the incision, taking care not to tear the esophagus. The lumen is carefully inspected for perforations. Perforations on the far (right) side of the esophagus may be accessed through the esophagotomy incision itself or by rotating the esophagus with stay sutures. Perforations are debrided before repair. It is very important that the mucosal–submucosal limits of any perforation are visible, before repair is started, and this visualization may require incision to extend the muscularis defect. The edges of the muscularis defect may otherwise hide the limits of a larger mucosal–submucosal defect, which may then be incompletely closed by the suture line, predisposing the repair to subsequent leakage. Omentum may be advanced directly through a diaphragmatic incision or it may be exteriorized via a paracostal approach (Figure 4.11) before advancement through a subcutaneous tunnel and passage between an intercostal space adjacent to the thoracotomy site. It is then sutured around the esophagotomy site. A defect of one‐quarter of the esophageal circumference may be primarily repaired, whereas larger defects are best patched or have their primary repair buttressed with a patch (Figure 4.12). Patching via diaphragmatic or intercostal muscle flaps is described elsewhere [15]. Experimental study of esophageal closure recommends a simple interrupted suture pattern to close the esophageal wall in one or two layers in preference to a simple continuous suture pattern single‐layer technique [16]. The study did not compare these techniques with a simple continuous suture pattern double‐layer technique, which appears to be a commonly employed method [1, 4, 14]. In double‐layer techniques, the mucosal–submucosal layer is closed, positioning the knots inside the lumen, while the muscularis–adventitial layer is closed with the knots on the outside. Synthetic monofilament suture material, such as polydioxanone or glycomer 631, of gauge 3‐0 or 4‐0 is typically employed. Suture bites are placed 3 mm apart and 3 mm from the incision/defect edges. The repair is leak‐tested by injecting saline to distend the esophagus, while an assistant digitally occludes the esophagus on either side. A chest drain is placed and a gastrostomy tube is also placed, via a separate left paracostal incision or using a percutaneous endoscopic technique. The lap sponges are removed and counted, the thoracic cavity is lavaged and suctioned, if grossly contaminated, and the thoracotomy incision is closed in layers.

Figure 4.10 Stay sutures employed to elevate and manipulate the esophagus in an atraumatic manner.

Figure 4.11 Omentum exteriorized via a paracostal laparotomy, in preparation for subcutaneous tunneling and passage through an intercostal space to augment an esophagotomy site.

Figure 4.12 Diaphragmatic patch (P) sutured in place to buttress the esophagus (E) after esophagotomy. Aorta (A), diaphragm (D), lung (L), and malleable retractors (M).

Case Report 4.1

A four‐year‐old male neutered Mastiff was presented after a four‐day period of regurgitation. No history of bone ingestion was noted but survey radiography demonstrated a very large bone (Case Figure 4.1) within the lumen of the distal esophagus. Forceps manipulation was unsuccessful as the bone was tightly wedged against the inflamed mucosa and was too large to be grasped by esophageal forceps. A left lateral thoracotomy was performed at the eighth intercostal space and an esophagotomy was performed. The esophagotomy site was closed in two layers and covered with an omental pedicle that had been tunneled through the diaphragm. A gastrostomy tube was placed via a paracostal incision, and a thoracic drain was inserted (Case Figure 4.2). Supportive treatment included management of the esophagitis (ranitidine 2 mg/kg twice a day IV for five days and sucralfate 2 g three times a day orally for five days), antibiotics (cefuroxime 10 mg/kg IV three times a day perioperatively), and analgesia. The dog recovered uneventfully.

Case Figure 4.1 Lateral thoracic radiograph identifying a very large bone within the lumen of the distal esophagus.

Case Figure 4.2 A thoracic drain and a gastrostomy tube are placed after removal of an esophageal foreign body via transthoracic esophagotomy.

Postoperative Care

      Multimodal analgesia and ongoing monitoring, ideally using a recognized veterinary pain scale, is important for the successful management of these patients [17]. Pain management may include opioid analgesics such as morphine (dogs 0.25–1 mg/kg IM every 4–6 hours; cats 0.05–0.5 mg/kg IM, SQ every 4–6 hours) or methadone (dogs 0.1–0.4 mg/kg IV every 4–6 hours; cats 0.05–0.2 mg/kg IV every 4–6 hours). To manage severe pain, fentanyl (dogs loading dose