Abstract
OBJECTIVE To determine the likelihood and outcome of esophageal perforation secondary to an esophageal foreign body (EFB) in dogs.
DESIGN Retrospective observational study.
ANIMALS 125 dogs evaluated for EFB at 2 veterinary teaching hospitals from January 2005 through December 2013.
PROCEDURES Data were retrieved from the medical record of each dog regarding variables hypothesized to be associated with esophageal perforation, whether esophageal perforation was present, and survival to hospital discharge. Variables were examined for associations with various outcomes.
RESULTS Bones (55/125 [44%]) and fishhooks (37/125 [30%]) were the most common types of EFBs. Fifteen (12%) dogs had an esophageal perforation (10 with a fishhook EFB and 5 with a bone EFB). No association was identified between dog body weight and esophageal perforation. Esophageal perforation was more likely in dogs with a fishhook EFB (10/37 [27%]) versus other EFBs (5/88 [6%]; OR, 6.1; 95% confidence interval, 1.9 to 9.6). Median interval from fishhook or bone ingestion to initial evaluation was significantly longer for dogs with (12 and 96 hours, respectively) versus without (1 and 24 hours, respectively) perforation. Thirteen of 15 (87%) dogs with esophageal perforation survived to hospital discharge, including all 10 dogs with perforation secondary to fishhook ingestion. Eight survivors with esophageal perforation required no surgical intervention.
CONCLUSIONS AND CLINICAL RELEVANCE Esophageal perforation was uncommon in the evaluated dogs with an EFB, and no surgical intervention was required for a large proportion of them. Fishhooks and delay between EFB ingestion and initial evaluation were risk factors for perforation.
Dogs may ingest nonfood or poorly digestible items that become lodged within the esophagus, most often in the thoracic portion.1,2 Clinical signs associated with EFBs include dysphagia, ptyalism, and regurgitation.3–5 Bones (rawhide bones and meat bones), fishhooks, and dog treats are the most common types of EFBs.6 Small-breed dogs such as West Highland White Terriers, Jack Russell Terriers, and Shih Tzus are reportedly at increased risk of an EFB relative to other dogs.1,6 Treatment for most affected dogs involves endoscopy, with retrograde removal via the mouth or dislodgement and redirection of the EFB into the stomach for subsequent digestion or surgical extraction.1,7
Dogs weighing < 10 kg (22 lb), with a bone EFB, or with EFB entrapment for > 72 hours are at greater risk of complications from an EFB than dogs without these characteristics.3,8,9 Such complications include esophagitis, esophageal stricture, aspiration pneumonia, and esophageal perforation.3,5,10 Esophageal perforation, often identified via esophagoscopy,11 may occur secondary to puncture from a sharp object or subsequent to esophageal necrosis. Perforation can lead to pneumomediastinum, pleuritis, mediastinitis, esophageal fistula formation, pneumothorax, pyothorax, sepsis, and death.3,6,12
Only a few reports10–13 exist regarding the likelihood or outcomes of esophageal perforation in dogs with EFBs. In addition, little consensus exists regarding the optimal management of dogs with esophageal perforation secondary to an EFB. Experimentally induced perforations < 12 mm in diameter can heal spontaneously.14 Still, some sources recommend surgical exploration whenever the esophagus is believed to be compromised.15 The objectives of the study reported here were to determine the likelihood of esophageal perforation secondary to EFB in dogs and to characterize the clinical findings, treatments, and outcomes associated with this condition.
Materials and Methods
Dogs and selection criteria
The electronic medical record databases at 2 veterinary teaching hospitals were searched to identify dogs that received a diagnosis of EFB over a 9-year period (January 1, 2005, through December 31, 2013). Search keywords included esophagitis, esophageal ulcer, esophageal perforation, foreign body, esophagoscopy, and endoscopy. All dogs identified in this manner were considered for inclusion in the study. Dogs were excluded if an EFB was identified radiographically but their owners declined further diagnostic testing or chose euthanasia over corrective treatment.
Data collection
Data were retrieved from the medical record of each dog regarding body weight at initial evaluation, interval from EFB ingestion to initial evaluation, nature and location of the EFB, presence or absence of esophageal perforation, method of diagnosis of esophageal perforation (radiography, endoscopy, surgery, or necropsy), perioperative complications, postoperative treatments, and outcome.
Statistical analysis
Collected numeric and categorical data were by use of statistical software.a Numeric data were tested for normality with the D'Agostino-Pearson omnibus test and compared between various groups with the Mann-Whitney U test. Distributions of categorical data were compared between various groups with the Fisher exact test. Values of P < 0.05 were considered significant.
Results
Animals
The initial medical record search revealed 132 dogs with an EFB. Seven dogs were excluded from the study because they were euthanized or discharged from the hospital without further diagnostic testing or without treatment following radiographic confirmation of an EFB (n = 5) or following complications related to endoscopic retrieval (2). The remaining 125 dogs, with a median body weight of 7.8 kg (17.2 lb; range, 0.9 to 60 kg [2.0 to 132 lb]), were included in the study.
EFBs
Types of EFBs included bones (n = 55 [44%]), fishhooks (37 [30%]), human food items (10 [8%]), dog treats (4 [3%]), toys (2 [2%]), endotracheal tubes (2 [2%]), a fishing line (1 [1%]), a stick (1 [1%]), and unknown items (13 [10%]). Median interval between EFB ingestion and initial evaluation for all 125 dogs was 4 hours (range, 0 to 1,440 hours). Median interval for dogs with a bone EFB was 24 hours (range, 1 to 1,440 hours), which differed significantly (P < 0.001) from that for dogs with a fishhook EFB (1.5 hours; range, 0 to 48 hours).
Esophageal perforation
Esophageal perforation was diagnosed in 15 of the 125 (12%) dogs on the basis of esophagoscopic (n = 10), thoracic radiographic (4), or surgical (1) findings. Ten of these dogs had a fishhook EFB, and 5 had a bone EFB. For dogs with radiographically detected perforation, free air was detected in the mediastinum (n = 2), periesophageal area (1), or thorax (1). Two of these dogs had a bone EFB, and the other 2 had a fishhook EFB. In the dog in which perforation was diagnosed during surgery, endoscopic removal of the EFB had originally been attempted but was unsuccessful.
Locations of EFBs in dogs with esophageal perforation included the distal portion of the esophagus (n = 4), midcervical portion of the esophagus (2), heart base region (2), cranial cervical portion of the esophagus (1), proximal portion of the esophagus (1), thoracic inlet region (1), midportion of the esophagus (1), and lower esophageal sphincter (1). In 2 dogs, the location was unknown.
Median body weight of dogs with and without an esophageal perforation was 9.3 kg (20.5 lb; range, 1.4 to 60 kg [3.1 to 132 lb]) and 7.3 kg (16.1 lb; range, 0.9 to 44 kg [2 to 96.8 lb]), respectively (P = 0.38). Dogs with fishhook EFBs were more likely to have esophageal perforation (10/37 [27%]) than dogs with any other type of EFB (5/88 [6%]; OR, 6.1; 95% confidence interval, 1.9 to 19.6; P = 0.002). Median interval between EFB ingestion and initial evaluation for the 15 dogs with a perforation was 24 hours (range, 0.4 to 1,440 hours), which differed significantly (P = 0.01) from that for the 110 dogs without a perforation (median, 2 hours; range, 0 to 1,080 hours). Considering only dogs with fishhook and bone EFBs, median interval between ingestion and initial evaluation was substantially and significantly longer for those with a perforation (12 and 96 hours, respectively) versus those without a perforation (1 [P = 0.007] and 24 [P = 0.003] hours, respectively).
Treatment
Removal of the EFB was successfully performed in 105 of the 110 (95%) dogs without esophageal perforation. This was achieved by endoscopic removal or endoscopic redirection of the object into the stomach (n = 103 [94%]), removal with hemostatic forceps (1 [1%]), and advancement into the stomach by use of a tube without endoscopic guidance (1 [1%]). In the remaining 5 (5%) dogs, the EFB spontaneously dislodged and moved down to the stomach prior to intervention.
Endoscopic removal of the EFB was attempted for 13 dogs with esophageal perforation and was successful for 9 dogs. For 8 of these dogs, the perforated area was evaluated endoscopically, and no surgical treatment was recommended. For the ninth dog, extensive perforation was identified following removal of a bone fragment, and the owners chose euthanasia. This dog had had the bone EFB for 4 days prior to initial evaluation. The 4 dogs for which endoscopic removal was unsuccessful subsequently underwent surgical removal of the EFB. Two dogs proceeded directly to surgical removal of the EFB, resulting in 6 dogs with esophageal perforation receiving surgical treatment overall.
The 6 dogs receiving surgical treatment underwent thoracotomy (n = 3) or exploration of the cervical region (3). Five of these dogs had a fishhook EFB, and 1 had a bone EFB. The bone EFB in the affected dog had been present for 12.5 days before initial evaluation, and this dog was euthanized during surgery after considerable necrosis of the esophagus was detected.
Treatment for the 13 dogs that survived EFB removal was decided by the attending clinician. None were fed by mouth for the first 12 hours after anesthetic recovery. Enteral feeding tubes were placed in 5 dogs (percutaneous gastrostomy tube in 3 dogs and esophageal feeding tube in 2 dogs). Ten dogs received a gastroprotectant (sucralfate [n = 8] with or without famotidine [6]). Antimicrobials were prescribed for 7 dogs (amoxicillin–clavulanic acid [n = 6] or amikacin and clindamycin [1]).
Two dogs with esophageal perforation that had undergone thoracotomy required chest tube placement to manage pneumothorax. One dog developed substantial pneumomediastinum following endoscopic EFB removal and was managed nonsurgically. Two dogs had radiographic evidence of postoperative aspiration pneumonia.
Outcome
All 110 (100%) dogs without esophageal perforation survived to hospital discharge, compared with 13 of 15 (87%) dogs with esophageal perforation. All 10 dogs with esophageal perforation secondary to fishhook ingestion survived to hospital discharge.
Discussion
Although many types of EFBs were identified in the dogs of the present study, only bone and fishhook EFBs resulted in esophageal perforations. This finding is similar to that in a previous study,11 in which perforation was identified only in dogs with bone EFBs. Although the reason only bone and fishhook EFBs resulted in perforation was unknown, we suspect this was attributable to the nature of the EFB. Bone EFBs may become firmly lodged within the esophagus, thereby applying pressure to the tissues with resultant necrosis and perforation. In contrast, fishhook EFBs are sharp and likely to puncture tissue.
In the present study, esophageal perforation was identified in 15 (12%) dogs with an EFB, and 2 of these dogs failed to survive to hospital discharge. In a previous study,6 esophageal perforation was identified in only 2 of 39 (5%) dogs with an EFB; 1 of these dogs died of pyothorax, and 1 recovered following nonsurgical management. In a second study10 involving 23 dogs with an EFB, 4 (18%) dogs had perforations ranging in length from 1 to 4 cm; 1 such dog developed cardiac arrest while anesthetized and died, whereas the other 3 survived to hospital discharge following surgical (n = 2) or medical (1) management. A third study9 involving 75 dogs with a fishhook EFB revealed full-thickness esophageal lacerations in 2 (3%) dogs, neither of which was treated surgically and both of which survived to hospital discharge. In a recent retrospective study13 of dogs and cats undergoing esophageal surgery, 50 of 63 (79%) dogs were surgically treated because of an EFB, and 30 (60%) of those dogs had esophageal perforation. The overall outcome for the dogs with a perforating EFB in that 2006 report13 was favorable, with > 80% surviving to hospital discharge (mortality rate, 17% [5/30]), which is a substantially better outcome than in a 1989 report,11 in which 4 of 7 dogs undergoing surgical treatment for esophageal perforation failed to survive.
Several potential reasons exist for differences in survival rates among studies, including advances in endoscopic, surgical, and anesthetic methods and equipment as well as the types of EFBs involved. In contrast to the 1989 report,11 in which all 10 dogs with esophageal perforation had a bone EFB, two-thirds of the dogs in the present study with perforation had ingested a fishhook. A previous study9 involving dogs and cats undergoing endoscopic and surgical removal of fishhook EFBs revealed perforation in only 2 of 75 (3%) animals, both of which were treated successfully with endoscopic removal and without surgical intervention. Although fishhooks may be more likely to result in a perforation than other items, we propose that they are less likely to cause extensive esophageal necrosis. This supposition is supported by the finding that all 10 dogs with esophageal perforation secondary to a fishhook EFB in the present study survived to hospital discharge, whereas 2 of the 5 dogs with perforation secondary to a bone EFB were euthanized.
Findings of the study reported here appeared to suggest that a delay in seeking veterinary attention increases the likelihood of esophageal perforation. This suggestion is supported by results of previous studies,1,3,16 in which an increased risk of esophageal perforation was identified for EFBs that remained lodged for > 72 hours (vs a briefer period). The interval between EFB ingestion and the time a dog is taken to the veterinarian is likely influenced by the owner's awareness of the event and perception of the associated risk. In the present study, dogs with fishhook EFBs were initially evaluated sooner after ingestion than dogs with bone EFBs, most likely because their owners witnessed ingestion or recognized the likelihood of injury.
Although other reports3,11 have suggested that small-breed dogs are more likely to have esophageal perforation secondary to an EFB than larger dogs, the present study yielded no evidence to support this association, given that median body weights for dogs with and without perforation were similar. Various other factors, namely size, type, and duration of EFB, likely play a more important role in the development of an esophageal perforation than patient size.
In the present study, the EFB was diagnosed in all 125 dogs on the basis of routine thoracic radiographic examination, but in only 4 of the 15 dogs with esophageal perforation was the perforation identified in this manner. This finding suggested that plain thoracic radiography lacked sensitivity for detection of esophageal perforation in dogs, which is supported by a previous report16 of 14 dogs undergoing surgical removal of an EFB. In the related study,16 no perforation was detected in any dog via thoracic radiography, but perforation was detected in 5 dogs via esophagoscopy or during surgery.16 This poor sensitivity could be explained by minimal air leakage due to the presence of the EFB. Another possibility is that esophageal rupture occurred in dogs with EFBs when they were anesthetized, during EFB removal, or as a result of insufflation or direct damage to the esophageal wall during esophagoscopy.17,18 In 10 of the 15 dogs with esophageal perforation in the present study, this perforation was first noted during esophagoscopy, and we could not exclude the possibility that the lesion was the result of the procedure itself rather than the EFB. Regardless of the cause and timing of the perforation, our findings suggested postprocedural thoracic radiography should be considered for dogs treated for EFBs.
In the present study, 9 of the 15 dogs with an esophageal perforation required no surgical intervention. No overt infection of the mediastinum or thoracic cavity was recorded for any of these dogs, suggesting rapid sealing of esophageal defects. Five of these dogs had ingested fishhooks, which likely caused small punctures that could be expected to heal spontaneously.14 However, it was interesting to note that 3 dogs with perforations secondary to bone EFBs were also successfully managed without surgery.
The study reported here had certain limitations, primarily attributable to its retrospective nature. Most importantly, information regarding the exact nature and dimensions of the esophageal defect was often limited, and reasons for surgical intervention were not clearly stated. The possibility could not be excluded that attempts at endoscopic removal of the EFB caused the perforation and not the EFB, although this event would suggest substantial underlying compromise. In addition, the 2 dogs with esophageal perforation that were euthanized during the EFB removal procedure were included in the outcome statistics, but these dogs may have had survivable lesions.
Overall, esophageal perforation secondary to EFB was uncommon in the dogs of the present study, and the outcome for affected dogs was encouraging. All 10 dogs with perforation secondary to a fishhook EFB survived, and many dogs with perforation required no surgical intervention.
ABBREVIATIONS
| EFB | Esophageal foreign body |
Footnotes
Graphpad Prism, version 7.0b, GraphPad Software Inc, San Diego, Calif. Available at: www.graphpad.com/scientificsoftware/prism. Accessed Oct 31, 2016.
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