Chest Wall Deformities Flashcards
Which of the following is the most common congenital chest wall deformity?
A. Pectus carinatum
B. Poland’s syndrome
C. Convex chest wall deformity
D. Pigeon chest
E. Pectus excavatum
ANSWER: E
COMMENTS: Pectus excavatum is the most common chest wall deformity in children, accounting for 88% of all chest wall deformities.
It is characterized by a concave chest wall deformity, with the sternum angled posteriorly toward the spine.
There is a male prevalence (3:1).
The defect may be present at birth but often becomes prominent during puberty due to rapid growth.
Symptoms can include dyspnea and exercise intolerance.
Surgical correction usually results in symptomatic relief, and there may be a slight improvement in pulmonary function tests.
Surgical repair will improve cosmetic appearance and the common psychosocial anxiety.
The Haller index should be calculated from an axial CT scan to determine the severity. It is the ratio of the widest transverse diameter within the ribs to the greatest length from the inner table of the sternum to the anterior surface of the vertebrae.
A ratio of >3.2 is considered as a severe defect.
Surgical repair may be performed with the open Ravitch procedure or with the minimally invasive Nuss procedure.
The Nuss procedure is currently favored due to less perioperative pain and smaller scars.
Pectus carinatum, also known as pigeon chest, is the next most common chest wall abnormality.
It is characterized by a protrusion of the sternum.
Management is initially nonsurgical with bracing. When worn appropriately, bracing can correct up to 75% of the deformities over time. However, noncompliance and discomfort are common.
Surgical correction is done via the open Ravitch proce- dure.
An osteotomy is made in the sternum, allowing it to be flattened to its normal position and contour.
Other congenital chest wall deformities exist, but are very rare.
Poland’s syndrome is characterized by the congenital absence of the pectoralis major, syndactyly, and occasionally missing ribs.
What are the typical chest wall deformities?
The most common are the caved in sternum or pectus excavatum (PEX) and the protruding sternum or pectus carinatum (PC).
When these defects coexist in the same patient they are called mixed deformities.
Also, deformities may be asymmetric or part of a syndrome such as the Currarino Silverman syndrome, which is characterized by a congenital cardiac malformation and pectus arcuatum, a wide, non-articulated, short sternum.
(Pearls & Tricks in Pediatric Surgery)
What are the demographic characteristics of pectus excavatum (PEX)?
The incidence of PEX has been traditionally described as 1 in 1000, and comprises 80% of all the pectus deformities.
However, and probably due to the rise of non-operative approaches to PC, there has been an increase in referrals of PC patients to pectus clinics in the last decades with a shift in the relative incidences in favor of PC resulting in a ratio of 1:1.
The sex distribution is predominantly male, with a 4:1 ratio.
A family history is common and connective tissue diseases are more frequently associated with pectus deformities.
(Pearls & Tricks in Pediatric Surgery)
How is PEX classified?
PEX can be classified as typical and atypical.
The typical forms can be classified as localized or diffuse, shallow or deep, and as symmetric or asymmetric (Fig. 3.1).
The atypical forms include mixed deformities and the Poland syndrome.
(Pearls & Tricks in Pediatric Surgery)
How is a patient with PEX studied?
The physical examination will provide information regarding the type of PEX and the probability of success with a non-surgical approach.
A vacuum bell connected to a vacuometer can predict how much pressure is necessary to correct the excavation and if the vacuum bell may be effective (Fig. 3.2).
We follow our patients with photos taken from 6 predetermined angles at diagnosis and follow-up.
In surgical candidates, a CT scan is performed to quantify the depth of the defect.
Physiologic testing may include stress echocardiography as well as a dynamic cardiac magnetic resonance imaging.
A history of metal allergy should be inquired and if uncertain, a nickel allergy test has to be performed to determine the patient will tolerate a steel bar. If not, a titanium bar will be needed.
We generally employ a 3D scanning system with virtual reconstruction for diagnosis and follow-up with a visual color-scale that varies according to its depth (Fig. 3.3).
(Pearls & Tricks in Pediatric Surgery)
What indices are most commonly used to measure the severity of PEX?
The Haller index is the original measure, and it results from the ratio between the lateral distance and the anteroposterior distance between the sternum and the spine, calculated by means of a chest CT scan at the point of maximum sternal depth.
This index was not originally validated and it is highly variable depending on sex, symmetry, the shape of the thorax, and the respiration phase in which the study is acquired.
Nowadays, the Correction Index has received validation and is more precise to discriminate affected from non-affected subjects.
(Pearls & Tricks in Pediatric Surgery)
What is the impact of PEX in the cardiopulmonary function?
In echocardiographic studies, functional alterations can be found such as ventricular dysfunction during exercise.
Employing dynamic cardiac magnetic resonance, 76% of the patients with PEX have shown some degree of right ventricular compression.
Recently, reports have demonstrated a relationship between sternal torsion and cardiac compression as well.
Normalization of cardiac function and structure has been reported after PEX repair.
More studies are currently underway.
(Pearls & Tricks in Pediatric Surgery)
What strategies are there for the treatment of PEX?
There are operative and non-operative treatments for patients with PEX.
In most cases, chest wall flexibility determines whether surgery will be necessary to solve the deformity.
Chest wall flexibility can be determined manually or utilizing a vacuometer.
However, some patients have very dysplastic sternums or rib cages that may require an operation no matter the flexibility they may have.
(Pearls & Tricks in Pediatric Surgery)
What is the non-operative treatment for PEX?
Since the first report in 2005, the use of a Vacuum Bell has become an option for patients with flexible rib cages [1].
This device is usually appropriate for patients under 11 years old with pectus depth less than 1.5 cm and with good compliance, who wear the device as many hours per day as possible.
It is noteworthy that an adjustment period of approximately 6 months of the presternal soft tissue is usually needed to avoid local lesions.
(Pearls & Tricks in Pediatric Surgery)
In patients with an indication of surgery, what approaches can be used?
Donald Nuss reported the minimally invasive placement of a retrosternal bar in the ′90 s. While many variants are described, open resection of costal cartilages is rare today and is generally reserved for extremely asymmetric or mixed deformities.
(Pearls & Tricks in Pediatric Surgery)
What safety measures should be applied during PEX surgery?
Thoracoscopic guidance is most commonly employed to decrease the possibility of undetected cardiac lacerations when introducing the tunnel dissector.
Upward traction on the sternum by vacuum bell or even a crane can be used (Fig. 3.4).
A subxiphoid finger can also be used to guide the bar and protect the heart [2].
(Pearls & Tricks in Pediatric Surgery)
What is the role of cryoanalgesia in pain control of PEX?
Cryoanalgesia has recently become a promising strategy for pain control during and after PEX repair.
Thoracic cryoanalgesia consists of the transitory demyelination of the 3rd to the 7th intercostal nerves by the application of a cryoprobe for 2 minutes each at −70 degrees Celsius (Fig. 3.5).
Randomized trials have demonstrated that cryoanalgesia is superior to thoracic epidural and patient controlled analgesia in terms of length of stay and requirement of complementary opioids.
(Pearls & Tricks in Pediatric Surgery)
How long does the bar stay in?
Usually 2.5–3 years.
Pearls & Tricks in Pediatric Surgery
What complications may be found during follow-up?
Pneumothorax, pleural effusion, and metal allergy.
The more serious complications are bar infection and displacement of the implant.
The worst complications are related to cardiac or aortic injury during or after PEX repair.
(Pearls & Tricks in Pediatric Surgery)
How is Pectus Carinatum (PC) classified?
PC is classified in chondrogladiolar and chondromanubrial types (Fig. 3.6).
If the protrusion involves the caudal third of the sternum, it is called chondrogladiolar, the most frequent variant.
The chondromanubrial type is a protrusion of the proximal segment of the sternum and frequently comprises a pectus arcuatum, an atypical variant consisting of a wide, short, unsegmented sternum.
If it is associated with a cardiac anomaly it is called Currarino Silverman Syndrome.
Also, PC may be classified in symmetrical, asymmetrical and mixed.
(Pearls & Tricks in Pediatric Surgery)
How is a patient with PC studied?
The evaluation of a patient with PC consists of a physical examination with medical photography destined for diagnosis and follow up.
CT scans or X-rays are reserved for special cases in which association with skeletal malformations are suspected.
In the last years, 3D scanning has become a relevant, radiation-free tool for the workup of chest wall malformations.
We perform 3D scans in all patients with PC at the moment of initial diagnosis, during, and after corrective treatments (Fig. 3.7).
(Pearls & Tricks in Pediatric Surgery)
What is the impact of PC in the health of patients?
PC is not an isolated protrusion of a segment of the sternum. Rather, PC consists of a dysplastic rib cage as a whole with posterior asymmetry, disproportionate shoulders, sternal rotation, chondro-costal anomalies, and scoliosis and kyphosis.
No cardiopulmonary anomalies are associated.
However, the psychosocial impact of PC includes shame, shyness, anguish, anxiety, depression, difficulties with social interactions and sports.
(Pearls & Tricks in Pediatric Surgery)