Cervical lung hernias (alternative plural: herniae), also known as apical lung hernias, are a subtype of lung hernias in which lung protrudes through the apex of the thoracic cavity.
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Epidemiology
Lung herniation of any form is rare. Cervical lung hernia is thought to represent only ~20% lung herniations overall, but as much as 60% of congenital lung hernias 1,2. Synchronous bilateral cervical lung herniations have been described 1. The cervical type of hernia is more commonly seen on the right. They are found twice as often in men as in women 2.
In adults, most apical hernias are acquired and either postoperative or post-traumatic 2,4,5.
In children, most cases of apical pulmonary herniation are congenital, and are often associated with hernias elsewhere in the body. Pediatric apical lung herniation tends to resolve spontaneously 2.
Associations
Risk factors
Phenomena that lead to an increased intrathoracic pressure increase the risk of a spontaneous apical lung hernia 2,4:
- musicians of wind/brass instruments
- chronic cough
- weightlifters
- emphysema
Clinical presentation
Apical lung hernias are often asymptomatic 1-3.
Symptoms when reported tend to be due to extrinsic pressure from the hernia on neck structures, e.g. dysphagia (esophageal) or coughing (trachea) 2.
Sometimes the diagnosis can only be made with a Valsalva maneuver which accentuates the herniation, improving its visibility on physical examination. Consistent with this, is that the hernias are commonly easy to reduce on physical examination.
Complications
- incarceration
- strangulation: very rare 6
- extrinsic compression of other neck structures, e.g. trachea, esophagus
Pathology
The lung apex is normally prevented from superior herniation by a combination of root of neck muscles, suprapleural membrane (Sibson fascia), and the parietal pleura 2,4. The suprapleural membrane, the name given to the endothoracic fascia as it covers the lung apex, attaches to the transverse process of the T1 vertebra, and is closely related anterolaterally to the first rib 2.
The Sibson fascia permits the lung apex to elevate superior to the first costosternal articulation, but this results in a possible site of weakness close to the midline in-between the anterior scalene and sternocleidomastoid muscles. It is therefore here, when there is a disruption of the fascia, that apical herniations occur, close to the body’s midplane, and hence their potential mass effect on midline neck structures, such as the trachea or esophagus 2,4.
The defect when it occurs is usually large, and therefore irreducibility of the lung is uncommon 2.
Etiology
Causes of cervical lung hernias may be congenital or acquired; in children, 60% of these hernias are congenital, whilst in adults, 60% are acquired 2.
- congenital
- acquired
- spontaneous (30%) 3
- traumatic
- iatrogenic: lung surgery
- pathological
- neoplastic
- inflammatory
- infection
Radiographic features
Plain radiograph / CT
Apical lung herniation is characteristically seen as a gas-filled mass in the supraclavicular region, which may be bilateral. Commonly, the abnormality is only appreciable if the image(s) are taken in full inspiration/during a Valsalva maneuver 1-3,5. The abnormality if large enough may be associated with tracheal deviation 2,4,5.
Fluoroscopy
Videofluoroscopy is a useful imaging adjunct when considering this diagnosis in view of the real time dynamic nature of the technique 2.
A barium swallow maybe helpful for cases in which the main differential is an esophageal diverticulum.
Treatment and prognosis
Surgical repair may be deemed essential in some cases, such as when the herniated lung is irreducible or there is compression of other neck structures, e.g. dysphagia. Occasionally repair will be for cosmesis 2,4.
Complications
- pneumothorax: central venous catheter insertion into a non-repaired herniated apical lung 2
Differential diagnosis
Other causes of a supraclavicular/upper paratracheal gas lucency need to be considered 2,3:
- pharyngocele: direct communication with pharynx
- laryngocele: direct communication with larynx
-
esophageal diverticulum: occasional gas-fluid level 2
- may be difficult to differentiate, occasionally a contrast swallow may be required
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