In medicine, the term "sequestrum" refers to a non-functional piece of tissue that is separated from healthy tissue.

The lung sequestrum (LS), also known as bronchopulmonary sequestrum or sequestration of the lung, is characterized by abnormal, non-functioning lung tissue. This does not have a normal connection to the tracheal system (tracheobronchial tree). In addition, the LS is not supplied by the blood vessels of the lungs (pulmonary arteries) directly from the right heart, as in a healthy child, but by atypical blood vessels that usually originate from the main artery (aorta).
Pulmonary sequestration accounts for only about 0.15 to 6% of all congenital lung malformations and is therefore one of the rarer malformations. A distinction is made between two forms of LS:

1) Extralobar sequesters (ELS) approx. 14-25%
Lung malformation separated from the rest of the lung tissue with its own pulmonary pleural covering. ELS are predominantly (90% of cases) located in the lower left part of the chest, adjacent to the spine. In addition, localizations outside the chest or in the diaphragm have been described and, rarely, there are also bilateral ELS. ELS can be associated with other malformations such as [LINK] congenital diaphragmatic hernia, [LINK] congenital pulmonary airway malformation (CPAM) and congenital heart defects. ELS are more common in boys (boys:girls = 4:1).

2) Intralobar sequestrants (ILS) approx. 75-86%
ILS are found in normal lung tissue and may contain air. In approx. 90% of cases, ILS are found in the lower lobe of the lung. There are mixed forms (hybrid lesions) with [LINK] congenital pulmonary airway malformations (CPAM).

ELS are often diagnosed before birth as part of regular ultrasound examinations, which, in close cooperation with the [LINK] prenatal diagnosticians, allows an adequate treatment strategy to be drawn up at an early stage. In both forms of LS, pneumonia is likely to occur in the course of life. We therefore usually offer surgical removal to protect against these infections before they occur.

Children are often presented to our prenatal consultation after an abnormal structure in the lungs has been diagnosed during ultrasound examinations during pregnancy. The lung malformation appears as a conspicuous, occasionally cystic structure in the lower posterior thorax (Fig. 2). As part of the investigation of chronically recurring pneumonia, an LS can also be seen on a chest X-ray. The differential diagnosis should include (LINK Bronchogenic cyst; LINK Congenital lobar emphysema; LINK Pulmonary sequestrum). To prove the suspected diagnosis of LS, the atypical arterial vasculature is visualized with a contrast medium using computer tomography.

In the case of a prenatal diagnosis, the aim is to deliver on the due date and this can usually take place naturally.

 

 

We operate on newborns with symptoms or even patients requiring ventilation soon or after stabilization. In children without symptoms, on the other hand, an X-ray of the chest (thorax) is carried out on the first day of life, followed by a thoracic computer tomography (CT) scan and then the surgical procedure and time of surgery are determined. The indication for surgery is generally determined together with the LINK Clinical Department of Paediatric Pneumology, Allergology and Neonatology in the interdisciplinary thoracic conference.
In asymptomatic patients, resection (surgical removal) of the malformation is often offered at the age of 6-12 months. This gives the healthy lung tissue an opportunity for early regeneration.

Minimally invasive surgical technique / thoracoscopic resection

We operate on newborns with symptoms or even patients requiring ventilation soon or after stabilization. In children without symptoms, however, an X-ray of the chest (thorax) is first taken on the first day of life and a thoracic computer tomography (CT) scan is then performed and the surgical procedure and time of surgery are then determined. The indication for surgery is generally determined together with the LINK Clinical Department of Paediatric Pneumology, Allergology and Neonatology in the interdisciplinary thoracic conference.
In asymptomatic patients, resection (surgical removal) of the LS is often offered at the age of 6-12 months. This gives the healthy lung tissue an opportunity for early regeneration.

Depending on the location of the LS, four small incisions (approx. 3-5 mm) are made on the right or left side of the chest using the thoracoscopic (minimally invasive) surgical technique. A thin tube (trocar) is inserted into the chest cavity through each of these incisions. Air is also blown into the chest cavity through one of these trocars and a camera is inserted (thoracoscopy). This allows the chest to be inspected. The other trocars are used to insert small working instruments that are needed to remove the malformation. The extent of the resection depends on the size of the findings and ranges from an "atypical" lung resection to removal of the entire affected lung lobe (Fig. 3).

A small drainage tube (so-called thoracic drainage or pleural drainage) is often placed in the pleural cavity (the space between the lung surface and the pleura) in order to maintain or restore the physiological negative pressure. Sometimes a controlled suction is also applied, which serves to pump wound secretions or air out of the pleural cavity. However, this drainage is usually removed again soon after the operation.

Not all children can undergo minimally invasive surgery. Factors such as birth weight, the extent of the malformation, other malformations (such as heart defects) and, above all, the urgency of the treatment all play a role here. The pediatric surgeon may also have to switch to an open surgical technique for technical reasons, for example if the overview during thoracoscopy is inadequate.

The extent of the resection depends on the size of the findings and ranges from an atypical partial resection to removal of the affected lung lobe (Fig. 3). During resection, it is particularly important to treat and completely close the atypical vessels.

 

Open surgical technique

The main difference between the open surgical technique and the minimally invasive technique is the type of access to the surgical site. Instead of three or four small incisions, a single, longer incision is made over the respective intercostal space - depending on the location of the LS - to provide access to the lung. With this technique, it may also be necessary to insert a chest drain, which is quickly removed again.
We always use absorbable suture material. Therefore, no suture removal is necessary after the operation. Scarring depends on the individual's disposition.

Patients with an LS have to stay in hospital for a few days after the operation. During this period, the child and mother are cared for by our pediatric nurses and the medical team on LINK pediatric surgery ward 66.
3 months after removal of the LS, the child will be seen again in our pediatric surgery outpatient clinic. Here we carry out both a clinical and a radiological (chest x-ray) follow-up. Thereafter, annual follow-up examinations are planned until adolescence, in case of symptoms also at short notice and, if necessary, together with our LINK Clinical Department of Paediatric Pneumology, Allergology and Neonatology.