Variations in Pulmonary Fissure: A Source of Collateral Ventilation and Its Clinical Significance.

Asha Joshi,Bharti Bhandari,Ranjana Verma,Pragatisheel Mittal,Arpita M Rai,Shyama Razdan

doi:10.7759/cureus.23121

Abstract

Introduction: Oblique and horizontal fissures divide the lungs into lobes. Assessing the incompleteness or absence of fissures is important when planning any surgical procedure in this region. This study aimed to investigate the incidence of variations in the fissures and their implication in clinical practice.Methods: The sample consists of 70 formalin-fixed lungs (32 right and 38 left lungs). These lungs were assessed for complete, incomplete, and absent fissures and any variations in the fissures on the sternocostal and mediastinal surfaces.Results: Oblique fissure was incomplete on the sternocostal surface in 18.75% and 21% and on the mediastinal surface in 25% and 21% on the right and left lungs, respectively. Additionally, it was absent in 10.5% of the left lung samples. The horizontal fissure was incomplete in 12.5% on both surfaces and was absent in 25% on the right lung samples, of which 50% had no oblique fissure. No accessory fissure was seen in any of the lungs.Conclusion: Incomplete and absent fissures can be observed in the right as well as the left lung, suggesting the source of collateral ventilation. This study imparts important information to pulmonologists doing bronchoscopic lung volume reduction therapy or bronchopulmonary segment resection and also to radiologists and anatomists.

Highlights

Oblique and horizontal fissures divide the lungs into lobes
Oblique fissure was incomplete on the sternocostal surface in 18.75% and 21% and on the mediastinal surface in 25% and 21% on the right and left lungs, respectively
It was absent in 10.5% of the left lung samples

Summary

Introduction

Oblique and horizontal fissures divide the lungs into lobes. The oblique fissure begins from the upper part of the hilum on the mediastinal surface and cuts the vertebral border at the fourth or fifth level of the thoracic spine. It courses along the costal surface, cuts the inferior border, reappears on the mediastinal surface, and ends at the lower end of the hilum. The horizontal fissure, which is seen only in the right lung, begins at the oblique fissure, courses along the costal surface, cuts the anterior border, appears on the mediastinal surface, and ends at the hilum [1]. The oblique fissure is usually seen via lateral radiography and appears as a curved band from the lateral aspect to the hilum under high-resolution computed tomography (CT) [1-3]

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