Small Animal Surgical Emergencies. Группа авторов

endoscopic view. The esophageal wall is often inflamed or ulcerated but unless significant trauma to the muscular layers of the esophagus has occurred, stricture is unlikely to follow (Figure 4.7).

Non‐surgical Treatment

      Esophageal Forceps

Esophageal forceps (Figure 4.8) are long forceps with serrated jaws and a blunted end that can grip a foreign body without causing iatrogenic injury to the esophageal wall. These forceps can be used for both cervical and thoracic esophageal foreign bodies.

Figure 4.6 Endoscopic view of a bone (condyle) lodged in the thoracic esophagus of a dog.

Figure 4.7 Esophagitis caused by pressure from the (removed) bone is now seen.

Figure 4.8 Custom‐made esophageal forceps with 75 cm shaft and toothed grasping jaws (inset). The profile is smooth when the jaws are closed to avoid engagement with the esophageal wall during forceps advancement. Inset – Sheep epiphyseal bone fragment alongside esophageal forceps.

      Endoscopic Technique

      Precisely directed manipulations to disengage the foreign body are possible when visualized in this way, although a better appreciation of the form of the foreign body, in particular, its distal end, may be obtained when combined with radiographic assessment. Care must be paid to detecting developing tension pneumothorax secondary to insufflated air passing through any perforations [8].

      Fluoroscopic Technique [9]

      The fluoroscopic technique is similar to the endoscopic method. Unsheathed forceps are advanced cautiously, with the animal's neck fully extended. Slight resistance is encountered at the thoracic inlet. The forceps are swept repeatedly alongside the foreign body to disengage it from the esophageal wall before grasping and gently withdrawing the foreign body. Theoretically, there is a greater risk of puncture of the esophagus by the foreign body during retrieval with this method. On rare occasions, esophageal puncture may be associated with aortic wall disruption and catastrophic hemorrhage, aortoesophageal fistula formation, or tracheobronchial puncture leading to acute respiratory complications or esophagobronchial fistula formation at a later stage [10–12]. Some resistance is met as the object passes the proximal cervical esophagus where it is constrained by the cricopharyngeus muscle, potentially necessitating temporary endotracheal extubation to complete retrieval.

      Rigid Endoscope Technique

      Forceps retrieval may also be performed using a rigid endoscope [2]. The leading edge of a rigid endoscope acts to lift the esophageal wall away from the foreign body helping to disengage sharp protrusions from the esophageal mucosa. A neuromuscular blocking agent such as atracurium (0.3 mg/kg slow IV) may help to relax the striated esophageal musculature, facilitating retrieval, although it must only be used where an appropriate facility for mechanical ventilation, monitoring, and potential agent reversal is available. Sharp protrusions must first have been manipulated into the opening of the esophagoscope, such that the esophageal wall is protected from puncture as the esophagoscope and the foreign body are withdrawn as one unit. The disadvantage of the rigid endoscope lies in the increased difficulty of advancing it down the esophagus in addition to the poorer image quality delivered in comparison with fiber‐optic instruments.

      Advancement into the Stomach

      Advancement into the stomach is used for some thoracic esophageal foreign bodies. Advancement of a foreign body into the stomach may be possible when it cannot be withdrawn without undue force. Subsequent gastrostomy is not required for bones treated in this manner as they are digested by gastric secretions and usually cause no further trouble [1, 2].

Surgical Treatment

An algorithm for the management of esophageal foreign bodies is shown in Figure 4.9. Table 4.1 summarizes the method of management and its relationship to outcome from a referral population and the current literature.

Figure 4.9 A management algorithm for esophageal foreign bodies. FB, foreign body.

Table 4.1 Published outcome data for esophageal foreign body management.

Method of management	Outcome
Retrieval with esophageal forceps	Endoscopic guidance: 60/66 retrieved [5] a
	Fluoroscopic guidance: 51/61 retrieved [10]
	Rigid endoscope: 83/90 retrieved [2]
Transthoracic esophagotomy retrieval after failed forceps manipulation	18/22 recovered, 2 euthanized intraoperatively, 2 diedb
Thoracotomy to repair esophageal perforation	9/14 recovered, 5/14 diedc

      ^a Non‐referral population.

      ^b Data summed from references [8, 10].

      ^c Data summed from references [8, 10, 13].

      Cervical Esophagotomy

      The cervical esophagus is exposed via a ventral midline approach. The paired sternohyoid muscles are bluntly separated along the midline, as are the deeper sternothyroid and more superficial sternocephalicus muscle pairs as the incision extends caudally. This exposes the trachea, which is retracted to the right, together with the recurrent laryngeal nerves that lie alongside it. This approach can be complemented with a cranial partial sternotomy, should a more caudal exposure prove necessary. The vagosympathetic trunks and common carotid arteries also run close to the esophagus. Soft plastic tubing may be advanced through the mouth and along the esophagus to aid the surgeon in identifying the esophagus via palpation. Other considerations are as for thoracic esophagotomy.

      Transthoracic Esophagotomy

Transthoracic esophagotomy is performed via a lateral thoracotomy approach [1, 4, 14] and is used for cases where the foreign body can neither be retrieved nor advanced (see