Pectus deformities

OVERVIEW: What every practitioner needs to know

Are you sure your patient has pectus excavatum deformity? What are the typical findings for this disease?

Pectus excavatum ('hollowed chest') is the most common congenital deformity of the anterior wall of the chest, in which several ribs and the sternum grow abnormally.

Key symptoms and signs:

  1. Shortness of breath

  2. Exercise intolerance and/or lack of endurance

  3. Chest pain

  4. Sternal depression which can be symmetric or asymmetric, shallow or deep, and short or long

What other disease/condition shares some of these symptoms?

These symptoms are not specific to pectus excavatum. The symptoms in the presence of the sternal deformity may be caused by other entities, such as asthma. Co-morbid conditions must be ruled out in order to attribute symptoms to the pectus deformity.

What caused this disease to develop at this time?

The deformity can be 1) familial (40% of cases), 2) associated with connective tissue disorders such as Marfan's syndrome, 3) secondary to pulmonary conditions that produce increased inspiratory pressures over time, e.g., subglottic stenosis or laryngomalacia or 4) idiopathic (majority of cases). Age of onset is during infancy in 30-80% of cases, However, the age of onset is often different than the age at which it becomes a concern, e.g., adolescence, when the pectus deformity can progress to become deeper and more apparent.

Current thinking is that the etiology for a pectus excavatum is an abnormality in costochrondral growth that may or may not reflect chronic mechanical stresses on the sternum and anterior costo-condral junctions.

Physical findings are a depression at the mid- or lower sternum with or without abnormal insertion of the ribs at the costo-sternal junction. The depression can produce flaring of the lower ribs below the sternum. The depression may be larger on one side of the chest than the other. A depth of the indentation >2.5 cm suggests a moderate deformity by one author's criteria. However, the deformity may be shallow and saucer shaped or deep and narrow.

What laboratory studies should you request to help confirm the diagnosis? How should you interpret the results?

The deformity is assessed with imaging studies.

The functional consequences of the pectus excavatum is assessed in several ways:

1. Spirometry to 1) measure the severity of restrictive lung/chest wall disease, and 2) rule out co-existent obstructive lung disease (specific evidence would be a reduced vital capacity in the absence of an abnormal FEV1);

2. Cardiopulmonary exercise testing on a treadmill or bicycle ergometer to assess the cardiopulmonary response to graded exercise (indices of cardiac limitations during exercise include a reduced oxygen pulse or oxygen consumption [VO2]). Cardiac limitation due to impaired ventricular filling in diastole during exercise has been implicated as a reason for exercise limitation in some children with pectus excavatum deformities. Breathing reserve is used to measure ventilatory limits to normal exercise in these children.

3. An echocardiogram is indicated when mitral valve prolapse is suspected. An electrocardiogram is used in some centers to diagnose conduction abnormalities, such as right bundle branch block. The clinical significance of the latter finding is controversial.

Would imaging studies be helpful? If so, which ones?

A limited computed tomography (CT) scan of the chest at the thoracic level where the pectus deformity is most severe describes the severity of the deformity. The Pectus Severity Index (PSI) or Haller index is defined as the distance from the deepest projection of the sternum into the chest to the anterior border of the vertebral body at the same level (transverse plane of the chest) divided by the longest lateral distance between the right and left ribs at the same level. This ratio is <2.5 for normal children; an abnormal ratio is defined as >3.25.

Confirming the diagnosis

The diagnosis is confirmed by physical examination. Clinical decisions for surgical correction of the pectus depend on reason for correction.

Cosmetic correction does not require more than assessment of the severity of the deformity. No functional limitations need be demonstrated. "Cosmetic" correction improves the self-image of the child in most cases. Some physicians argue this is sufficient reason to correct the deformity.

Correction of the pectus deformity to relieve pain has no standard guidelines to assure the pain will be diminished after surgical repair.

Exercise intolerance by history, confirmed to be due to ventilatory limitation or cardiac limitation by formal exercise stress testing is an indication for correction.

Exercise intolerance and breathlessness, associated with restrictive chest wall disease documented by spirometry, is an indication for surgery in the presence of a significant pectus deformity.

Combinations of criteria proposed to proceed with surgical correction include the following: symptoms, history of progression of the deformity, Haller Index>3.25, cardiac compression or displacement by CT scan, mitral valve prolapse due to cardiac compression by the pectus deformity, right bundle branch block on electrocardiogram, restrictive lung disease by spirometry, history of failed pectus repair, and body image disturbance.

Evidence is based on large case series after variable intervals of observation (see references below).

If you are able to confirm that the patient has pectus excavatum deformity, what treatment should be initiated?

Treatment can be observation or surgical intervention. There are no indications for urgent surgical repair. Reduced exercise and activity level will reduce symptoms until surgery, if indicated, occurs.

Surgical treatment includes the Ravitch repair, with removal of selected chondral cartilage sections along 4-5 ribs bilaterally and insertion of struts for support, or the Nuss procedure, with placement of 1-2 surgical bars internally beneath the sternum for 2-4 years. Recurrence rate of the pectus excavatum after either procedure is 2%. The Nuss procedure is considered minimally invasive compared to the Ravitch procedure. Both effectively reduce the pectus deformity and are associated with improved self-image and perception of improved exercise tolerance.

What are the adverse effects associated with each treatment option?

The age of intervention is 8-12 years or older. Surgery in infants and young children historically produced a secondary asphyxiating thoracic dystrophy due to fibrosis of the chest wall in some patients and is no longer indicated at this age.

Post-operative pain can last for several weeks following surgical repair.

The Nuss procedure is associated with a post-operative pneumothorax in up to 50% of patients but requires intervention in <3% of cases.

Nuss bar migration was originally a complication but has been solved with better lateral fixation of the bars along the ribs.

What are the possible outcomes of pectus excavatum deformity?

Pectus deformities do not resolve unless they are due to a pulmonary etiology (such as upper airway obstruction) that resolves or is treated. The chest wall deformity in these cases returns toward normal over months and years.

Families are told that image improves and cardiopulmonary limitations and chest wall pain may improve with surgical correction of the true deformity. Reported outcomes include improved self-image, perceived exercise tolerance, reduced chest wall pain, and improved cardiopulmonary function. However, objective measures of cardipulmonary function do not always improve. Nevertheless, 92-97% of patients report a good or excellent outcome (without specific outcomes delineated.)

What causes this disease and how frequent is it?

Pectus excavatum is the most common chest wall deformity in children. Male:female ratio is 4:1. Prevalence among normal Caucasian children is 38 per 10,000 births, and 7 per 10,000 births among African-American children. However, 66% of children with Marfan's syndrome and many children with Noonan syndrome have pectus excavatum deformities. Underlying connective tissue disorders, such as Ehlers-Danlos syndrome, osteogenesis imperfecta, and homocystienuria, may increase the risk of developing the deformity.

Although up to 80% of children will have the deformity detected in infancy or early life, the intrauterine influences predisposing to pectus excavatum are not known.

30-40% of patients have a positive family history for a pectus deformity. The mode of inheritance varies from autosomal dominant and recessive to X-linked and multifactorial patterns among families.

Co-morbid conditions depend on whether the pectus is associated with an underlying syndrome, e.g., Marfan's syndrome. Associated conditions include mitral valve prolapse, scoliosis, asthma, past history of congenital heart disease or diaphragmatic hernia and repair.

How do these pathogens/genes/exposures cause the disease?

The relationships between genes, pulmonary mechanical stresses on the chest wall, and growth pattern determinants post-natally are not understood.

What complications might you expect from the disease or treatment of the disease?

Complications of the disease are progressive deformity through adolescence with associated worsening of symptoms.

Complications of the surgical repair include the following:

1) Recurrence: 2%.

2) Early post-operative complications (reported for either the Ravitch or Nuss procedure) occurred in 8% of patients. These included pneumothoraces (4% needing treatment), Horner's syndrome (15% in one series), and <1% of patients with arrhythmias, pericardial effusion, pericarditis, perforated myocardium, or infection.

3) Late complications of the Nuss procedure include bar displacement requiring revision (4%), bar allergy (3%), and infection in <1% of treated patients.

Are additional laboratory studies available; even some that are not widely available?

No additional laboratory values are used for clinical decision making.

How can pectus excavatum deformity be prevented?

There are no known ways to prevent a pectus excavatum deformity. Progression may be prevented in those cases where an underlying pulmonary condition that increases pleural pressure swings is treated.

What is the evidence?

Evidence for the surgical correction of pectus deformities is based on large case series for each surgical approach. There have been no controlled comparative trials of one technique compared to another.

Selected references include the following:

Fonkalsrud, EW. "912 Open pectus excavatum repairs: Changing trends, lessons learned: One surgeon's experience.". World J Surg. vol. 33. 2009. pp. 180-190.

Jaroszewski, D, Notrica, D, McMahon, L. "Current management of pectus excavatum: A review and update of therapy and treatment recommendations". J Am Board Fam Med. vol. 23. 2010. pp. 230-239.

Kelly, RE, Goretsky, MJ, Obermeyer, R. "Twenty-one years of experience with minimally invasive repair of pectus excavatum by the Nuss procedure in 1215 patients.". Ann Surg. vol. 252. 2010. pp. 1072-1081.

Kelly, RE. "Pectus excavatum: Historical background, clinical picture, preoperative evaluation and criteria for operation.". Seminars in Pediatric Surgery. vol. 17. 2008. pp. 1810193.

Kelly, RE, Cash, TF, Shamberger, RC. "Surgical repair of pectus excavatum markedly improves body image and perceived ability for physicial activity: Multicenter Study.". Pediatrics. vol. 122. 2008. pp. 1218-1222.

Koumbourlis, AC. "Pectus excavatum: Pathophysiology and clinical characteristics.". Paediatric Respiratory Reviews. vol. 10. 2009. pp. 3-6.

Lawson, ML, Mellins, RB, Paulson, JF. "Increasing severity of pectus excavatum is associated with reduced pulmonary function.". J Pediatr. vol. 159. 2011. pp. 256-261.

Malek, MH, Berger, DE, Marelich, WD. "Pulmonary function following surgical repair of pectus excavatum: A meta-analysis.". European Journal of Cardio-thoracic Surger. vol. 30. 2006. pp. 637-643.

Kelly, RE. "“Multi-center Study of Pectus Excavatum, Final Report: complications, Static/Exercise Pulmonary Function, and Anatomic Considerations,”". J Am Coll Surg. vol. 217. 2013. pp. 1080-1089.

O’Keefe, J, Byrne, R, Montgomery, M, Harder, J, Roberts, D, Sigalet, DL. "”Longer term effects of closed repair of pectus excavatum on cardiopulmonary status,”". J PedSurg. vol. 48. 2013. pp. 1049-1054.

Ongoing controversies regarding etiology, diagnosis, treatment

Ongoing controversies include the following:

1. Is surgical correction of the pectus excavatum for improvement in self-image and self-esteem indicated? The term "cosmetic" surgery implies an improvement in image but does not address adolescent adjustment issues.

2. The structure-function correlates for pectus excavatum and either restrictive lung disease or cardiopulmonary exercise limitations are crude at best. Specific features of the pectus excavatum and/or the

thorax that better predict cardio-pulmonary functional limitations are needed.

3. The relative importance of each of the criteria used to consider surgical treatment has not been assessed. Combinations of features are used to justify surgical repair but use of lists of indications varies from center to center.

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