Posttraumatic transmediastinal pulmonary hernia: An extremely rare clinical entity

CT scan showing transmediastinal herniation of the right lower lobe.

Central Message.

We report the first case of posttraumatic transmediastinal pulmonary hernia in a young woman following blunt force trauma.

Lung herniation (LH) is an infrequent clinical entity that consists of protrusion of part of the lung parenchyma outside the rib cage.¹ In case of blunt chest trauma, part of the lung parenchyma can herniate through chest wall defects caused by rib fractures or by a chondral-costal or clavicle-sternal dislocation.² Given the rarity of the phenomenon, there is no standardized management. We report the first case of posttraumatic transmediastinal pulmonary hernia in a young woman following blunt force trauma.

Clinical Summary

A 28-year-old woman was admitted to our emergency intensive care department after a fall (10 meters high). The patient had a previous clinical history of major depression. Informed consent for publication of this study could not be obtained given the neurological damage the patient experienced as a result of the blunt-force trauma. Institutional review board approval was not required due to the type of work (ie, case report).

On admission, the patient presented with severe respiratory failure. A chest computed tomography scan showed bilateral pneumothorax with pleural effusion and multiple vertebral somatic and rib fractures. A diffuse pneumomediastinum along the esophagus was also appreciated, but imaging tests excluded an esophageal perforation.

In the retrocardiac area, a voluminous partly aerated mass was recognized that went from the basal portion of the right chest to the left side, passing through the mediastinum between the aorta and esophagus. The first clinical suspect was a transmediastinal herniation of the right lower lobe in the left hemithorax (Figure 1). The bilateral pneumothorax was immediately treated with bilateral pleural drainage; subsequently, the patient underwent surgery.

Figure 1.

Computed tomography scan showing part of right lower lobe protruding contralaterally through the mediastinum, between aorta and esophagus. A, Axial view. B, Coronal view.

The herniated portion of the right lower lobe was reduced via a biportal video-assisted thoracoscopic surgery approach (Figures 2 and 3). Exploration of the entire lung parenchyma showed the presence of deep parenchymal tears involving the lower apical segment of the herniated tissue with significant vascular congestion (Video 1).

Figure 2.

Intraoperative view of the right lower lobe reduced via a bi-portal video-assisted thoracoscopic surgery approach.

Figure 3.

Intraoperative photograph showing part of the left lower lobe protruding through the mediastinal defect.

A wedge resection of the lacerated area was then performed; other small parenchymal breaches were sutured with continuous polydioxanone 3-0 sutures; the mediastinal defect between aorta and esophagus was finally repaired by continuous polydioxanone suture. At the end of the procedure, no air leak was evident and the residual lung parenchyma showed good reexpansion. The patient returned to the intensive care unit.

Discussion

LH is a rare condition characterized by part of lung parenchyma herniated through the chest wall. According to the Morel Lavallée classification, pulmonary hernias are distinguished according to their etiology and anatomical location.³ Among these, the most frequent form is posttraumatic (80% of cases). To our knowledge, cases of transmediastinal pulmonary hernia have never been described before. In the present case, the area of airborne content in the posterior mediastinal location with associated prominent pneumomediastinum raised suspicion of a posttraumatic esophageal tear. Only a careful review of computed tomography images revealed the presence of air bronchogram and related vascularization of the right lower lobe, which made its way contralaterally through the mediastinum between the aorta and esophagus.

In most cases, pulmonary hernias are treated conservatively. In this case, surgery was mandated to avoid risks of strangulation of the lung parenchyma. We believe that a minimally invasive surgical approach may be considered, especially if performed within the first few hours of the incident. Surgery involves closure of the herniary breach with possible use of prostheses based on the wideness of herniary ports. In our case, a direct suture of the mediastinal pleura between the esophagus and aorta was performed, with no need for prosthesis.

Conclusions

This is the first case ever reported of a transmediastinal LH. The management of LH should always be tailored to a patient's conditions. Careful management of chest trauma is always needed.

Supplementary Data

Video 1

The herniated portion of the right lower lobe is reduced via a video-assisted thoracoscopic approach. Video available at: https://www.jtcvs.org/article/S2666-2507(23)00041-X/fulltext.