One Labrador retriever, whose original injury occurred four days before surgery, had severe pleural thickening and a 5-cm-long
stick fragment completely within the pleural space. The other dog, the Doberman pinscher, whose original injury occurred 48
hours before surgery, also had severe gross pleuritis and three stick fragments within the pleural space.
Thoracic closure was routine, with thoracostomy tubes placed in all dogs and additional closed suction (two) or Penrose (one)
drains placed appropriately in relation to the wounds at the surgeon's discretion.
Bacterial culture
Samples were collected for aerobic and anaerobic bacterial cultures intraoperatively in six dogs; five culture results were
positive. Mixed anaerobic infections were the most common, and bacteria identified included Bacillus species, coagulase-positive Staphylococcus species, Clostridium
sporogenes and Micrococcus species, Clostridium perfringens, Clostridium sordellii, and Enterobacter amnigenus biogroup 2.
Postoperative treatment
After surgery, all dogs were treated with intravenous fluids, analgesics (local and systemic), and antibiotics. Five dogs
received supplemental oxygen. In two cases, surgically placed thoracostomy tubes became dislodged and were replaced percutaneously
because of large volumes of on-going effusion. Thoracostomy tubes remained in place for a mean of three days (range = one
to six days). Thoracostomy tubes were removed based on decreased fluid production. The volume of pleural effusion removed
varied considerably from dog to dog, with a mean of 10.1 ml/kg/day and a range of 1.4 to 28.3 ml/kg/day.
Figure: 2. A ventrodorsal thoracic radiograph of a Labrador retriever that presented for evaluation of dyspnea 10 days after
thoracotomy. Note the wires in the sternebrae and the large volume of primarily right-sided pleural effusion.
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The two dogs with the longest duration of medical treatment before definitive surgical exploration and repair (the Doberman
pinscher and a Labrador retriever) had marked on-going suppurative effusion for five and six days, respectively. The Doberman
pinscher's pleural effusion resolved, while the Labrador retriever was discharged eight days after surgery with mild pleural
effusion, which was thought to be resolving, and then returned 48 hours later with respiratory distress. Severe suppurative
pleural effusion was identified on radiographic examination (Figure 2). Indwelling thoracostomy tubes were placed, and the effusion finally resolved after 10 additional days of supportive care,
including aspiration of the tube every four to six hours and intravenous antibiotics (metronidazole 10 mg/kg every eight hours
and enrofloxacin 10 mg/kg every 24 hours). Ultrasonography during this hospitalization documented suspected multiple small
intrapleural and intraparenchymal abscesses. The 1- to 3-mm fluid pockets were considered too small to percutaneously drain
and too extensive to warrant another thoracotomy.
Long-term outcome
All the dogs survived to hospital discharge. The dogs were hospitalized for a median of seven days (range = three to 12 days).
One Labrador retriever's total hospitalization was 18 days over two admissions.
Figure: 3. A ventrodorsal thoracic radiograph of the same dog as in Figure 2 at its six-month recheck after medical therapy
for pyothorax. No clinical signs of restricted activity were present, although an increased interstitial pattern is observed.
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The German shorthaired pointer developed a draining tract 48 months after the first injury and 12 months after the second
injury in a separate site, caudal to the first injury. Thoracic radiographs at this point revealed mild bony proliferation,
swelling, and a possible draining tract adjacent to the ninth rib. A subsequent ultrasonographic examination revealed a 3-cm-long
echogenic linear foreign body as well as a smaller linear foreign body within a convoluted hypoechoic draining tract. Both
foreign bodies were associated with faint acoustic shadowing. Wooden fragments were subsequently removed surgically; they
were found in the same region as the first traumatic injury four years earlier and on the same side as the second injury a
year earlier.
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