Anatomical considerations for the surgical approach to the canine accessory lung lobe.

Objective: To describe (1) the surgical anatomy of the accessory lung lobe (ALL) including vasculature and pulmonary ligamentous attachments and (2) lobectomy through a right thoracotomy and median sternotomy.

Study Design: Cadaveric anatomical study.

Animals: Nine adult canine cadavers, free of disease affecting the thoracic cavity and lung parenchyma.

Methods: Median sternotomy and right and left lateral thoracotomies were performed to describe and image relevant variations in anatomy using accompanying photographs and thorough voice notes. Consideration for ALL removal via right thoracotomy at the fifth through seventh intercostal spaces and median sternotomy were documented and compared.

Results: The median weight of the cadavers was 20.85 kg (6.9-45.5 kg). Variation in the configuration of venous drainage of the ALL was identified. The lateral vein varied in its location and was also observed to combine with the medial vein in one cadaver. The pulmonary ligament attached to the ALL in a caudally pointing apex on the dorsal process of the lobe. Medial and lateral extensions of the ALL parenchyma were found. The ALL was most easily accessed by a right lateral thoracotomy at the sixth intercostal space. Although not optimal, removal of this lung lobe via median sternotomy was feasible.

Conclusion: Significant variations were found in the blood supply to the ALL. A right lateral thoracotomy at the sixth intercostal space was preferred for a surgical approach to the ALL.

Clinical Significance: Surgeons should be aware of several anatomical particularities including the venous drainage, ligamentous attachments, and parenchymal extensions of the ALL.