Base the choice of a thoracotomy approach on the location of the entry wound and radiographic findings. In patients with entry wounds in the ventral cervical area or near the thoracic inlet, sternum, or spine, use a median sternotomy since structures on either side of the thorax may have been damaged.^7,8 For patients with entry wounds on the lateral side of the thorax distant from the midline, an intercostal thoracotomy may be considered, particularly if radiographs suggest that damage is confined to the side of the thorax in which the entry wound is located. A disadvantage of intercostal thoracotomy is that it requires an accurate estimation of the object's entry site into the thorax. If the impaling object passes through the thoracic wall at an oblique angle, it may enter the pleural space several intercostal spaces distant from the site of skin penetration. Additionally, the opposite side of the thorax may have been penetrated. For this reason, use a median sternotomy if you are uncertain about the impaling object's course.

In unstable patients, perform thoracic exploration before wound exploration so that life-threatening intrathoracic injuries can be addressed without delay. All patients with thoracic impalement injuries have the potential to be unstable, so the surgeon and surgery team must be prepared to address any changes in patient status. The surgeon should also be prepared to completely or partially remove damaged lung lobes and to ligate or repair lacerated blood vessels. While only one dog in this case series required lung lobectomy and none of the dogs damaged major vascular structures, it would be prudent to be prepared for any surgical finding.

Once all major intrathoracic damage has been addressed, try to remove all remnants of the foreign body. In many cases, debris from penetrating sticks can be found near the thoracic entry wound. In addition, thoroughly inspect any areas within the thorax that appear discolored or demonstrate evidence of prior hemorrhage. Finally, explore, débride, and lavage the entry wound itself.

Antibiotic therapy

Thoracic impalement injuries carry a real risk of infection of the wound or thoracic cavity; three of the dogs in this case series developed persistent pyothorax or draining tracts after their initial hospitalization and treatment.¹³ It is likely that early surgical intervention and removal of all visible foreign material are the most important factors in preventing chronic infections and that antibiotic therapy plays a complementary role.

Our culture results suggest that most dogs have mixed aerobic-anaerobic contamination of tissues, and resistant organisms are uncommon because of the community-acquired source of contamination. (Most multidrug-resistant organisms develop only in the hospital setting with antibiotic use selecting for the resistant strains. In contrast, most bacteria outside of hospitals are susceptible to the common antibiotics as dictated by their intrinsic characteristics. For example, streptococcus is consistently resistant to the fluoroquinolones, while anaerobes are resistant to the aminoglycosides.) So obtain both anaerobic and aerobic cultures during surgery. Institute broad-spectrum antibiotics before surgery if the injury occurred more than a few hours before presentation; otherwise, antibiotics may be instituted after culture samples are obtained. Antibiotic selection should be based on the results of sensitivity testing, if possible. Since a high incidence of anaerobic contamination was noted in our study, antibiotics effective against anaerobes should be administered.

CONCLUSION

The present study was limited by its retrospective nature, the small number of dogs, and the selection of only dogs that underwent thoracotomy. We did not attempt to identify dogs that were treated by more conservative means, and the number of these cases at our institutions during the study period was not determined. In addition, some dogs may have died of hemorrhage, pneumothorax, or other sequelae of impalement before surgery. Despite these limitations, we conclude that dogs that undergo early controlled removal of impaling thoracic foreign bodies combined with surgical exploration of the thorax can have an excellent long-term prognosis.

Julia Zitz, DVM*
Elizabeth Rozanski, DVM, DACVIM (internal medicine), DACVECC
Dominique Penninck, DVM, DVSc, DACVR
John Berg, DVM, DACVS
Department of Clinical Sciences
Cummings School of Veterinary Medicine
Tufts University
North Grafton, MA 01536
*Dr. Zitz's current address is The Ohio State University, College of Veterinary Medicine, Columbus, OH 43210.