Clinical case: Postpneumonectomy syndrome

Author: Carlos Suarez-Quian, PhD • Reviewer: Prof. Joel A. Vilensky, PhD
Last reviewed: July 11, 2023
Reading time: 15 minutes

In this article, we describe a clinical case of a man who presented with hemoptysis due to an infection. Unfortunately, further complications and problems appeared that ultimately resulted in a postpneumonectomy syndrome. Stick around to find out more details about the meaning of this diagnosis, its difficult management, together with relevant anatomical considerations.

Key facts
Right-sided aortic arch	A right-sided aortic arch is a type of aortic arch variant that is characterized by the aortic arch passing to the right of the trachea. There are three main types that vary based on the subclavian and common carotid branching patterns
Kommerell’s diverticulum	Presence of an aneurysm-like funnel-shaped widening at the origin and proximal-most segment of an aberrant subclavian artery. It results from abnormal development of the aorta with a failure of regression of a remnant of the fourth primitive right or left dorsal arch.
Lobular composition of the lungs	The right lung has upper, middle, and lower lobes, which are differentiated by two fissures, one oblique and one horizontal. The left lung is separated into two lobes, an upper and a lower, by the oblique fissure
Bronchial arteries	Bronchial arteries provide nourishment to the supporting lung tissues but do not participate in gas exchange. The left bronchial artery arises from the aorta, while the right bronchial artery arises from a posterior intercostal artery or sometimes from the left bronchial artery.

After reviewing this case you should be able to describe the following:

What is meant by a right-sided aortic arch and how it develops.
What is meant by a Kommerell’s diverticulum.
The lobular composition of the lungs. And what is meant by the lingual of the lung.
What is the anatomy and function of the bronchial arteries.

This article is based on a case report published in the Journal "Case Reports in Surgery" in 2015, by Caroline C. Jadlowiec, Beata E. Lobel, Namita Akolkar, Michael D. Bourque, Thomas J. Devers, and David W. McFadden.

Contents

Case description
Surgical and Anatomical Considerations
Explanations to objectives
Sources

+ Show all

Case description

History

The patient was a 54-year-old man who was known to have a right-sided aortic arch and Kommerell’s diverticulum (Figures 1+2). Kommerell’s diverticulum – or, diverticulum of Kommerell – is the term used to characterize the presence of an aneurysm-like funnel-shaped widening at the origin and proximal-most segment of an aberrant subclavian artery regardless of whether right or left.

Figure 1. 3D reconstruction from CT showing a right-sided aortic arch with a Kommerell’s diverticulum.

Complaints and clinical presentation

He presented with refractory hemoptysis, which resulted from a rapidly growing mycobacterium avium complex (MAC) infection. This infection could not be controlled by bronchial artery embolization. Accordingly, a left lower lung lobectomy and lingular segmentectomy were performed (Figure 3).

Figure 2. A: PA chest x-ray showing right-sided descending aorta. B: Axial CT showing right-sided aortic arch. DA, descending aorta; AA, ascending aorta. (these images are not from the patient described in this case but are illustrative of the information presented here)

Although antimycobacterial agents continued to be administered, the patient’s MAC infection relapsed in the left upper lobe. Eight months after the initial surgery, a complete left pneumonectomy was performed. The extirpated lung was strongly adherent to the pericardium and diaphragm. The chest incision was closed after thorough irrigation of the thoracic cavity. There were no immediate postoperative complications and the patient was discharged on postoperative day 14.

Figure 3. Dissection image showing the mediastinal surface of left lung from a cadaver

Three months after the lung removal surgery, the patient developed shortness of breath with no history of asthma or congenital heart disease. His symptoms worsened over the course of several days, necessitating intubation, and positive pressure ventilation. A CT scan at this time revealed a mediastinal shift to the left.

Diagnosis

He was diagnosed with postpneumonectomy syndrome (PPS) resulting in constricted middle lobar bronchus and right lower bronchus. In both cases the bronchi were compressed between the right pulmonary artery and the right descending aorta, so that the airway was barely patent (Figure 4). The patient became hypoxic shortly after bronchoscopy, possibly resulting from mucosal edema.

Figure 4. Axial CT showing the patient 3 months after the left lung removal. The blue arrow in A shows the constricted middle lobar bronchus that is caused by pressure from the right pulmonary artery against the right-sided descending aorta. The blue arrow in B shows a similar constriction in the right lower bronchus. Note that the left thoracic cavity does not appear black in this image. After the pneumonectomy, a scar tissue fills in the gap and gives the soft tissue density in these images instead of black air density.

Management & Evolution

Thus, surgical repositioning of the mediastinum was considered essential to maintaining the patient. The left thoracic cavity was reopened, and total adhesiolysis was performed. To restore the normal mediastinal position, an open-window thoracostomy was created with resection of the second to the ninth rib. Piles of gauze were then inserted into the chest cavity, mildly forcing the mediastinum to the right side. The inserted gauze and dressings were redone every day for three months. CT scan showed a repositioned mediastinum and sufficiently patent airways however after five days with the gauze in place (Figure 5).

Figure 5. Axial CT images showing the same structures as in Figure 4 but showing the open thorax in which gauze was inserted to shift the mediastinal contents back toward their normal alignment (white arrows) and thereby reduce pressure on the middle lobar bronchus (blue arrow in A) and right lower bronchi (blue arrow in B). The insertion of the gauze successfully resulted in an opening of the middle lobar bronchus and right lower bronchi. (It is important to differentiate here between the right middle bronchus and the middle lobar bronchus. The right main bronchus first gives rise to the right upper bronchus. The remaining structure continuing from that point on is the middle lobar bronchus. The right middle and lower bronchi then arise from the middle lobar bronchus).

Three months subsequent to the repositioning of the mediastinum, the thoracostomy was closed using a latissimus dorsi muscle flap covering the heart. The patient was discharged without any dressings needed. Two months after thoracoplasty, the mediastinum had not reshifted back to the abnormal position (Figure 6).

Figure 6. Axial CT images showing similar structures as in Figure 4. Here the gauze has been removed and the thoracic wall closed. Note that the middle lobar bronchus (blue arrow in A) and right lower bronchi (blue arrow in B) remain patent, clearly demonstrating that the sustained pressure from the gauze resulted in a permanent shift of the mediastinum to its normal alignment.

Surgical and Anatomical Considerations

PPS is a rare complication of pneumonectomy. The syndrome is characterized by a large mediastinal shift that results in compression of parts of the tracheobronchial tree. The symptoms are typically shortness of breath, stridor, and heartburn. Although it is mostly found in patients with a right-sided aortic arch, it can be found in those with normal aortic arch anatomy.

A mediastinal shift may occur when there is differential pressure in the left and right hemithoraces. After pneumonectomy the mediastinum shifts to the side of the extirpated lung and the lung in the contralateral hemithorax becomes over-expanded. A mediastinal shift is usually well shown on a chest radiograph by the lateral shift of the trachea to the lung-extirpated side (Figure 7). However, a mediastinal shift is not simply a shift in the coronal plane. After right lung removal there is a counterclockwise rotation to the right of the heart and the tracheobronchial tree along with a tracheal shift to the right. The left main stem bronchus becomes stretched and the lower lobe bronchus is kinked over the descending aorta. After left pneumonectomy, there is a clockwise rotation of the heart, and the right main stem bronchus becomes stretched over the vertebral bodies in a normal patient; but, over the descending aorta in a patient with an aorta on the right side.

Figure 7. Chest x-ray of a patient following left pneumonectomy. Note the marked left shift of the trachea (highlighted with green) associated with a mediastinal shift. For illustrative purposes (not the patient in this case).

In the case described here, the surgeons used one of a number of available techniques to realign the mediastinum and decompressed the middle lobar bronchus and right lower bronchus. The gauze procedure used by the surgeons restored normal respiration to the patient.

Explanations to objectives

Objectives

What is meant by a right-sided aortic arch and how it develops.
What is meant by a Kommerell’s diverticulum.
The lobular composition of the lungs. And what is meant by the lingual of the lung.
What is the anatomy and function of the bronchial arteries.

Right-sided aortic arch

A right-sided aortic arch is a type of aortic arch variant that is characterized by the aortic arch passing to the right of the trachea. Different types exist that vary based on the subclavian and common carotid branching patterns. In the first type, the branching is simply a mirror image of what is typically found in a normal left-sided arch. This type results from interruption of the dorsal segment of the left arch between the left subclavian artery and the descending aorta, with regression of the right ductus arteriosus in the hypothetical double aortic arch.

In the second most common type (and the type shown by the patient in the case described here) there is an aberrant left subclavian artery associated with Kommerell's diverticulum (see explanation 2). This type results from interruption of the dorsal segment of the left arch between the left common carotid and left subclavian arteries with regression of the right ductus arteriosus in the hypothetical double aortic arch.

The last type is much rarer than the other two and involves isolation of the left subclavian artery. This one results from interruption of the left arch at two levels, with one level between the left common carotid and left subclavian arteries and the other level distal to the attachment of the left ductus arteriosus.

Kommerell’s Diverticulum

Kommerell’s diverticulum – or, diverticulum of Kommerell – is the term used to characterize the presence of an aneurysm-like funnel-shaped widening at the origin and proximal-most segment of an aberrant subclavian artery regardless of whether right or left. The diverticulum results from abnormal development of the aorta with a failure of regression of a remnant of the fourth primitive right or left dorsal arch.

Lobular Composition of the Lungs

The right lung has upper, middle, and lower lobes, which are differentiated by two fissures, one oblique and one horizontal. Horizontal fissure divides the upper from the middle lobes. It reaches the anterior border of the lung at the level of the sternal end of the fourth costal cartilage. The oblique fissure divides the lower from the middle and upper lobes and is similar to the oblique fissure in the left lung. Anteriorly, the horizontal fissure is superior to the oblique fissure but as the oblique fissure moves posteriorly it also travels in a superior direction and becomes superior to the horizontal fissure.

The left lung is separated into two lobes, an upper and a lower, by the oblique fissure, which extends from the costal to the mediastinal surface of the lung (Figure 3). The left lung also has a homologous structure to the middle lobe of the right lung, a projection of the upper lobe termed the “lingula”. The term means, “little tongue”. That is why when the surgeons removed the left lower lobe, they had to do an additional segmental resection to remove the lingual, which is part of the upper lobe. The oblique fissures are known as the “major” fissures whereas the horizontal fissure is known as the minor fissure.

Anatomy & Function of the Bronchial Arteries

The lungs are supplied by two distinct vascular systems: the pulmonary and bronchial arteries. The pulmonary arteries conduct low pressure deoxygenated blood to the lungs They supply 99% of the blood flow to the lungs and are critical to in gas exchange at the alveolar capillary membrane.

The bronchial arteries carry high-pressure oxygenated blood to the lungs. The left bronchial artery arises from the aorta, the right bronchial artery arises from a posterior intercostal artery or sometimes from the left bronchial artery. Bronchial arteries provide nourishment to the supporting lung tissues but do not participate in gas exchange. They do however anastomose with the pulmonary arteries at the capillary level. In various conditions that involve pulmonary artery compromise, the bronchial arteries and their anastomotic connections may dilate causing a greater percentage of the cardiac output to flow through the bronchial artery system. Thus, dilation of these vessels on images should alert the physician to investigate the underlying pathology.

Sources

All content published on Kenhub is reviewed by medical and anatomy experts. The information we provide is grounded on academic literature and peer-reviewed research. Kenhub does not provide medical advice. You can learn more about our content creation and review standards by reading our content quality guidelines.

Reference:

Karasaki T, Tanaka M. Life-Threatening Postpneumonectomy Syndrome Complicated with Right Aortic Arch after Left Pneumonectomy . Case Reports in Surgery, Volume 2015, Article ID 768067, 4 pages.
Modified by Joel A. Vilensky PhD, Carlos A. Suárez-Quian PhD, Aykut Üren, MD.

Authors:

Joel A. Vilensky
Carlos A. Suárez-Quian
Aykut Üren

Layout:

Abdulmalek Albakkar
Adrian Rad

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