Congenital pulmonary airway malformation (CPAM) is a congenital disease in which the lung tissue is interspersed with numerous cysts (= air-filled cavities). The incidence is 1:11000 to 1:35000 live births.

CPAM usually affects only one lobe of the lung and is found on the left side in around 60% of cases. In up to 4% of cases, CPAM is reported to occur on both sides. Today, CPAM is often diagnosed before birth as part of regular ultrasound examinations. As there are different congenital malformations (LINK Bronchogenic cyst; LINK Congenital lobar emphysema; LINK Lung sequestrum), it is correct to speak of a "congenital thoracic malformation" at this stage.

Children with CPAM can be completely unremarkable after birth. Depending on the severity of the malformation, the possible spectrum of symptoms ranges from slightly labored breathing (dyspnea) or increased respiratory rate (tachypnea) to global lung failure due to severe bilateral underdevelopment of the lungs (lung hypoplasia).

According to the US pathologist Stocker, the following types of CPAM are distinguished:

Acinar dysplasia (Stocker type 0)) - very rare, here the entire lung is missing

 

Macrocystic CPAM (Stocker type 1) - common

One or more cysts with a diameter greater than 2 cm. Microscopically, the cysts are lined with ciliated respiratory epithelial cells * and mucus-forming cells. The cyst wall consists partly of smooth muscle and elastic tissue.

* Cilia = fine mobile cell extensions; epithelium = collective term for covering tissue and glandular tissue.

Microcystic CPAM (Stocker type 2) - common
Numerous, small, communicating cysts smaller than 1 cm. Microscopically, the thin cyst wall contains smooth muscle and is lined with cubic to cylindrical ciliated epithelium.

Solid CPAM (Stocker type 3) - rare
Solid, adenomatoid, airless (non-cystic) mass. Microscopically consisting of thin (englumigenic), immature structures with accumulation of mucus-forming cells.

(Peripheral cystic CPAM (Stocker type 4)) - very rare, may be confused with malignant tumors

If CPAM causes symptoms, surgical removal is usually recommended. It is not clear whether children who are asymptomatic also require surgery. Even in cases where the CCAM is not space-occupying or displaces healthy structures in the chest, many surgeons wait before operating.

Children are often presented to our LINK prenatal consultation after an abnormal structure in the lungs has been diagnosed during ultrasound examinations during pregnancy. The lung malformation appears as a small, medium or large cystic structure with blood supply from the pulmonary circulation, which stands out from the normal lung structure (Fig. 1). The differential diagnosis should include (LINK Bronchogenic cyst; LINK Congenital lobar emphysema; LINK Pulmonary sequestrum).

The aim is to give birth on the due date and this can usually take place naturally. A caesarean section is only indicated in the case of pronounced findings.

 

 

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
Depending on the location of the malformation, four small incisions (approx. 3-5 mm) are made on the right or left side of the chest during 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 remaining 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 the removal of the entire affected lobe of the lung.

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 the open surgical technique for technical reasons, for example if the overview during thoracoscopy is inadequate.

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 CPAM - 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 a CPAM 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 CPAM, 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 scheduled 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.