Overview
Definition:
Pectus excavatum is a congenital anterior chest wall deformity characterized by a caved-in or sunken appearance of the sternum and rib cage
The Nuss procedure is a minimally invasive surgical technique used to correct this deformity by inserting a tailored metal bar behind the sternum to elevate it.
Epidemiology:
Pectus excavatum is the most common congenital chest wall deformity, occurring in approximately 1 in 300 to 1000 live births
It is more common in males and often presents during adolescent growth spurts
A significant proportion of patients have a family history, suggesting a genetic component.
Clinical Significance:
Severe pectus excavatum can lead to cardiopulmonary compromise, impacting exercise tolerance, causing dyspnea, chest pain, and arrhythmias
It also has significant psychological and social implications for affected individuals, making surgical correction an important aspect of thoracic surgery and reconstructive procedures.
Clinical Presentation
Symptoms:
Progressive worsening of chest asymmetry
Dyspnea on exertion
Chest pain, often pleuritic or substernal
Palpitations or irregular heartbeats
Reduced exercise tolerance
In severe cases, syncope or dizziness
Psychological distress and body image issues.
Signs:
A palpable depression of the sternum and adjacent ribs
Widened intercostal spaces anteriorly
Scapular winging may be present
Auscultation may reveal diminished breath sounds at the bases or murmurs due to cardiac displacement
Skin may be normal or show some hyperpigmentation over the depressed area.
Diagnostic Criteria:
Diagnosis is primarily clinical based on physical examination
Objective measurement of chest wall asymmetry is crucial
Imaging, particularly CT scans, is used to quantify the severity using the Haller index (ratio of transverse diameter to anteroposterior diameter of the chest, normal > 2.5)
Cardiopulmonary function tests are used to assess functional impact.
Diagnostic Approach
History Taking:
Detailed history regarding the onset and progression of the deformity
Questions about associated symptoms like shortness of breath, chest pain, and exercise limitations
Inquire about family history of chest wall deformities or connective tissue disorders
Assess psychological impact and social concerns.
Physical Examination:
Observe chest wall symmetry from anterior, lateral, and posterior views
Palpate the sternum and ribs to assess depth and rigidity of the depression
Check for associated deformities or syndromic features (e.g., Marfan syndrome, Poland syndrome)
Assess for cardiac displacement and auscultate heart and lungs thoroughly.
Investigations:
Chest X-ray (PA and lateral views) for initial assessment of the deformity and cardiac silhouette
CT scan of the chest for precise measurement of the deformity (Haller index), assessment of mediastinal structures, and planning surgical repair
Echocardiography to evaluate cardiac function and position
Pulmonary function tests (PFTs) to assess lung volumes and airflow, especially in symptomatic patients
ECG to rule out cardiac abnormalities.
Differential Diagnosis:
Pectus carinatum (protrusion of the sternum)
Asymmetric rib hypoplasia
Poland syndrome
Acquired chest wall deformities post-trauma or surgery
Congenital scoliosis
Connective tissue disorders leading to skeletal abnormalities.
Management
Initial Management:
Observation for mild cases or in pre-pubertal children
Counseling regarding the condition and treatment options
Referral to specialists (thoracic surgeon, cardiologist, pulmonologist, psychologist).
Medical Management:
Primarily supportive and psychological
Pulmonary rehabilitation and exercise programs can improve cardiopulmonary function and exercise tolerance in some patients, but do not correct the deformity
No specific pharmacologic treatment for the deformity itself.
Surgical Management:
The Nuss procedure is the gold standard for significant pectus excavatum
Indications include a Haller index > 3.2, significant cardiopulmonary symptoms, or severe cosmetic deformity causing psychological distress
The procedure involves sub-pectoral placement of a curved stainless steel or titanium bar to lift the sternum
Cryoanalgesia for post-operative pain control is common.
Supportive Care:
Post-operative care is critical and includes vigilant pain management, respiratory physiotherapy to prevent atelectasis and pneumonia, and monitoring for bar-related complications
Mobilization is encouraged as tolerated
Nutritional support is generally not a primary concern unless there are associated comorbidities.
Complications
Early Complications:
Hemorrhage (intercostal vessel injury)
Pneumothorax
Bar displacement or migration
Wound infection
Seroma or hematoma
Pain
Injury to adjacent organs (heart, lungs).
Late Complications:
Chronic pain
Bar extrusion or breakage
Recurrence of deformity (less common with proper bar placement)
Granuloma formation around the bar
Restricted chest wall motion
Persistent cardiac or pulmonary symptoms.
Prevention Strategies:
Meticulous surgical technique, including proper dissection plane, accurate bar placement and fixation, and use of appropriate size and curvature of the bar
Prophylactic antibiotics
Adequate post-operative pain control and respiratory physiotherapy
Patient education on activity restrictions
Careful patient selection.
Prognosis
Factors Affecting Prognosis:
Severity of deformity at presentation
Age at surgery
Presence and severity of cardiopulmonary symptoms
Adherence to post-operative care and rehabilitation
Presence of associated syndromic conditions.
Outcomes:
The Nuss procedure generally yields excellent cosmetic and functional outcomes
Most patients experience significant improvement in chest wall symmetry, exercise capacity, and reduction in symptoms
Long-term satisfaction rates are high
Complete correction of cardiopulmonary function is often achieved.
Follow Up:
Regular follow-up is required, typically at 1, 3, 6, and 12 months post-operatively, and then annually until bar removal (usually 2-3 years post-op)
Follow-up includes assessment of wound healing, pain, functional status, and chest wall appearance
Imaging may be performed to monitor bar position if concerns arise.
Key Points
Exam Focus:
Nuss procedure indications (Haller index, symptoms, cosmesis)
Steps of the Nuss procedure (bar insertion, stabilizers)
Common complications (hemorrhage, pneumothorax, bar displacement, infection, pain)
Post-operative care priorities (pain control, respiratory physiotherapy)
Contraindications (relative and absolute).
Clinical Pearls:
The Haller index is critical for quantifying severity and guiding surgical decisions
Use of cryoanalgesia significantly improves post-operative pain management
Careful dissection to avoid pleural or pericardial injury is paramount
Bar stabilizers are crucial for preventing bar migration
Early mobilization and aggressive physiotherapy are key to a good functional outcome.
Common Mistakes:
Inadequate assessment of cardiopulmonary status pre-operatively
Incorrect bar sizing or curvature leading to suboptimal correction or complications
Insufficient fixation of the bar, leading to displacement
Underestimation of post-operative pain and inadequate management
Poor patient selection or inadequate pre-operative counseling.