Trauma-Associated Pulmonary Laceration in Dogs-A Cross Sectional Study of 364 Dogs

Abstract

In this study, we describe the computed tomography (CT) features of pulmonary laceration in a study population, which included 364 client-owned dogs that underwent CT examination for thoracic trauma, and compared the characteristics and outcomes of dogs with and without CT evidence of pulmonary laceration. Lung laceration occurred in 46/364 dogs with thoracic trauma (prevalence 12.6%). Dogs with lung laceration were significantly younger than dogs in the control group (median 42 months (interquartile range (IQR) 52.3) and 62 months (IQR 86.1), respectively; p = 0.02). Dogs with lung laceration were significantly heavier than dogs without laceration (median 20.8 kg (IQR 23.3) and median 8.7 kg (IQR 12.4 kg), respectively p < 0.0001). When comparing groups of dogs with thoracic trauma with and without lung laceration, the frequency of high-energy motor vehicle accident trauma was more elevated in dogs with lung laceration than in the control group. No significant differences were observed between groups regarding tge frequency and length of hospitalization and 30-day mortality. Similar to the human classification scheme, four CT patterns are described in dogs in this study: Type 1, large pulmonary laceration located deeply in the pulmonary parenchyma or around an interlobar fissure; Type 2, laceration occurring in the paraspinal lung parenchyma, not associated with vertebral fracture; Type 3, subpleural lung laceration intimately associated with an adjacent rib or vertebral fracture; Type 4, subpleural lesions not associated with rib fractures. Complications were seen in 2/46 dogs and included lung abscess and collapse.

Keywords: blunt trauma; cystic lesion; laceration running head; pulmonary laceration in dogs; thoracic CT; thoracic trauma.

Scheme 1

Frequencies of different types of thoracic trauma in the control group (0) and in the study group (1). High-energy motor vehicle accident trauma resulted more frequently in the study group than in the control group. Thoracic bite trauma was less frequently associated to lung laceration lesions. These differences were not statistically significant. Falling from a height (H), motor vehicle accident (M), bite trauma (B).

Figure 1

Box plot graph showing the body weight distribution in group 0 (control group) and affected group (group 1).

Figure 2

Box plot graph showing the age distribution in group 0 (control group) and affected group (group 1).

Figure 3

Type 1 and Type 2 lung lacerations. (A) The transverse section of the thorax in a traumatized dog. In the left lung, there are two ovoid pseudocystic lesions, one located deep in the lung parenchyma and another in the subpleural area of paraspinal region, not associated with spinal fracture. Note the air–fluid level in the deep lesion in (A) and in the superficial lesion in (B) (pneumohematocele). Pneumothorax is present on the right side. (B) The transverse section of another traumatized dog with small Type 1 and Type 2 lung lacerations, both with mixed air–blood content. The dog had no vertebral fractures.

Figure 4

(A). Type 2 pulmonary laceration (arrow) in a traumatized dog with T12-13 subluxation. (B,C) Sagittal and dorsal views of the spine. Note the T12–13 misalignment in the sagittal view (B) with reduced intervertebral space (C).

Figure 5

(A) Type 3 lung laceration (arrow) associated to rib fracture. Note the increased opacity in the lung parenchyma surrounding the laceration, consistent with pulmonary hemorrhage, and the pneumothorax. (B) Type 4 small subpleural lung lacerations not associated with rib fracture.

Figure 6

(A) Large subpleural, paravertebral lesion in a dog, without evidence of vertebral fracture (Type 2) (arrow). The lesion contained blood and air. Note the bilateral pneumothorax. (B) Left parasagittal view in the same dog, showing two lesions around an interlobar fissure, almost completely filled with blood.

Figure 7

Comparison of computed tomography (CT) images of the left lung in a traumatized dog with Type 2 and Type 4 lung lacerations. (A) The first CT examination showed two cystic, air-containing lesions and ipsilateral pneumothorax (without rib or vertebral fractures). (B) After 5 days, CT showed air–fluid levels in both lesions and a small amount of air visible in the pleural cavity.

Figure 8

(A,B) Transverse and right-parasagittal views of the thorax in a patient with subpleural lung laceration and massive pneumothorax, with subsequent lung collapse.

Figure 9

(A–C) Right lateral projections of a traumatized dog showing changes over time of lung lacerations. (A) On admission, an alveolar pattern was noted in the middle lobe area (circle) surrounded by a diffuse interstitial pattern. (B) Two days later, in the same area (circle) a large ovoid lesion with hydroaeric level was noted (pneumohematocele). (C) Four days after admission, in the same area (circle) the lesion was clearly visible (hematocele); another small lesion, with air–fluid levels, was noted.