A proposed anatomical classification of the pulmonary fissures.

No method of classifying pulmonary fissures currently exists, however, the nature of the fissure is of great importance in planning operative strategy for thoracoscopic pulmonary resection where an incomplete fissure may contribute to post-operative air leakage. In order to provide a framework for description of operative technique and to allow meaningful comparison between different surgical series, we propose a fissural classification based on both the degree of completeness of the fissures and the location of the pulmonary artery at the base of the oblique fissure. Completeness of a fissure is graded in four stages: grade 1--complete fissure with entirely separate lobes; grade 2--complete visceral cleft but parenchymal fusion at the base of the fissure; grade 3--visceral cleft evident for part of the fissure; grade 4--complete fusion of the lobes with no evident fissural line. The relationship of the pulmonary artery to the oblique fissure is described by the term 'fissural balance'. The pulmonary artery lies centrally to the oblique fissure in a 'normally balanced' fissure. Anterior or posterior displacement of the artery is referred to as anterior or posterior 'imbalance'.