Children with funnel chest may present clinically in one or more of the following ways.
(1) asymptomatic ;
(2) limited physical activity;
(3) pain
(4) cognitive appearance (aesthetics).
There is no evidence that this type of deformity shortens life expectancy or limits the type of occupation. However, many children are symptomatic, which is worrisome, and less responsive to various persuasions and cautions. Two patients may present with the same degree of deformity with vastly different symptoms, but this does not mean that neither requires treatment, nor does it mean that the exact same level of attention and treatment is needed.
1. Restricted physical activity
In children with funnel chest, the causes of physical activity limitation have been studied in some detail. In a case described by Sauerbruch in 1920, an 18-year-old patient with dyspnea and palpitations with limited physical activity was able to work 12 hours a day after surgery without fatigue. Energy is a word with a more complex meaning, but is at least partially related to cardiopulmonary function.
2.Funnel chest and heart
The relationship between the subjective symptoms of funnel chest and the mechanical compression of the heart and lungs is unclear, and there is no evidence of a relationship, but most patients have subjective symptoms that disappear or resolve after surgery.
In 1987, an association with pulmonary artery funnel compression and mitral valve prolapse was proposed; in 1995, an association with right ventricular compression was proposed; in 2000, Hoeffel suggested an association with tricuspid stenosis; in 2005, and Lawson suggested an association with inferior vena cava compression, altered cardiac conduction system, and restrictive pulmonary syndrome, respectively. Some patients present with subjective symptoms such as dyspnea, physical limitation, chest pain and palpitations.
In this case, the anterior-posterior diameter of the thorax is significantly reduced, the heart is compressed and shifted to the left. Often they do not realize the degree of preoperative ease of fatigue until after surgical correction. In recent years, attempts have been made to detect these children by objective means, but these means are not a direct test of the degree of physical tolerance.
During the morphologic evaluation of funnel chest, CT films may also show a change in the shape of the heart due to sternal recesses that distort and alter the atrial morphology of some hearts. The depressed sternum squeezes the heart toward the spine and can lead to volume limitation of the left ventricle but, more often, to simultaneous compression of the right atrium, particularly the right ventricle: limited ventricular wall motion, tricuspid stenosis, partial obstruction of the ventricular outflow tract and outflow tract, and pulmonary valve stenosis. The degree of cardiac compression is related to the severity of the funnel chest (Haller index).
The pathophysiological result of cardiac compression is an increase in filling pressure due to restriction of right hemi-ventricular filling. The beat-to-beat output decreases when the patient is physically active in the standing position and returns to normal in the supine position. Cardiac compression can also cause deformation of the cardiac fibrous skeleton, allowing for a higher incidence of mitral valve disease. This explains the ability of surgery to completely alleviate some of the symptoms and signs.
The incidence of mitral valve prolapse is 0,6-2,4% in the general population and up to 30-65% in patients with thoracic deformities such as funnel chest, according to Udoshi in 1979 and SaintMezard et al. in 1986. In patients with thoracic deformity and mitral valve prolapse, a small anteroposterior diameter of the thorax was found, suggesting the involvement of thoracic deformity in the development of mitral valve prolapse in this population. Therefore, it is mostly a functional mitral valve prolapse. In this population, mitral valve prolapse is secondary to deformation of the mitral annulus following compression of the heart toward the spine.
Mitral valve prolapse in patients with thoracic malformations was first studied by Raggi in 2000 using electron beam CT. In the normal population, the spherical surface of the heart was shown on CT to be spherically round with little or no contact with the chest wall. After studying a large number of patients with thoracic anomalies and mitral valve prolapse, he found that 82% of patients had a large contact surface between the heart and the anterior chest wall, which could cause compression of the heart and result in organic deformation of the mitral valve leading to prolapse. The morphologic and quantitative CT data reported by the authors in support of the “diastolic restriction” theory are summarized as follows.
1. The anteroposterior diameter of the thorax from the inner surface of the chest wall to the front of the corresponding vertebrae was reduced;
2. CT reconstructions show an increase in the contact area between the heart and the inner surface of the thorax;
3, the angle between the mitral valve plane and the ventricular septal plane is increased to a right or obtuse angle, and the increased angle provides a quantitative indicator of the degree of mitral annular deformation.
The authors also describe two types of thoracic morphology that may lead to cardiac extrusion deformation and secondary mitral valve prolapse.
1. horizontal “8” shaped thorax, such as funnel chest: the thoracic vertebrae are close to the sternal axis with sternal depression;
2.Convex posterior “C”-shaped thorax, only the anterior-posterior diameter is shortened, such as straight back syndrome.
In patients with Haller’s index of 2,4-3,25, Haller’s index does not determine the presence of cardiac compression. Therefore, in these patients, morphological examination of the heart with color Doppler ultrasound, performed in the supine and upright positions under exercise stress testing, is required to determine the presence or absence of impaired cardiac reserve function.
The results of the Coln study also confirm that this form of mitral valve prolapse is acquired and functional, and that it recovers spontaneously after thoracic correction surgery with a good prognosis. Although no complications due to mitral valve prolapse were documented in this study, some complications do sometimes occur, such as.
1. infective endocarditis
Transient ischemic attack (TIA) and transient visual changes can occur when there is fibrinous embolism and involvement of the posterior cerebral vessels of the ophthalmic artery or Willis vascular ring.
2. Tendon rupture
This includes arrhythmias (atrial fibrillation, atrial arrhythmias, ventricular tachycardia), sudden death (bradycardia and cardiac arrest due to long QT, abnormally increased vagal tone) and progressive deterioration of mitral valve insufficiency leading to heart failure. Therefore, it can be concluded that color Doppler echocardiography can be seen as the gold standard for the diagnosis of mitral valve prolapse in patients with funnel chest.
3. Tendon prolongation
This condition includes possible dilatation and deformation of the mitral annulus. Ultimately color Doppler ultrasound can be used to quantify the severity of mitral regurgitation based on the severity of concomitant mitral valve prolapse and is classified as mild, moderate, or severe based on quantitative parameters. Color Doppler ultrasound can also be used to visualize changes in ventricular filling flow through the mitral and tricuspid valves, which is similar to constrictive pericarditis. In addition, because mitral valve prolapse is functional and acquired in patients with funnel chest, there is not necessarily a thickened or enlarged mitral valve, which is more often seen in diseases that are specific to the involved valve structures.
3, Funnel chest and inferior vena cava compression
In 2005, Yalamanchili et al. suggested that a more in-depth mechanism of impaired cardiac reserve function in funnel chest is compression of the inferior vena cava. Some patients with funnel chest exhibit paradoxical respiratory movements of the thorax, i.e., inward sternal invagination during inspiration, which differs from the expansion of the thorax during inspiration in healthy individuals. The paradoxical respiratory motion itself determines a series of alterations in cardiac function, decreased tolerance to physical activity, decreased oxygen delivery to skeletal muscle, decreased hypoxia threshold and decreased pulse oxygen concentration suggestive of oxygen concentration, different from that of the odd vein (constrictive pericarditis).
The presence of paradoxical respiratory movements is also a factor that exacerbates thoracic deformities during adolescence and young adulthood. During adolescence, parents and family physicians wrongly expect children to engage in more intense physical activity to modify the muscular structure of the thorax and improve the appearance of the thoracic deformity. In fact, the increased metabolic demand for physical activity causes an increase in respiratory rate and depth, which creates a vicious circle: the markedly enhanced paradoxical respiratory movements further compress the inferior vena cava, exacerbating the sternal depression and mechanically compressing the heart or indirectly causing obstruction of venous return.
Echocardiography during inspiration in this scenario has been reported to suggest a decrease in both blood flow through the mitral and tricuspid valves and in output per beat, suggesting that it may be caused by diaphragmatic compression of the inferior vena cava, possibly by paradoxical sternal depression. Another finding was a decrease in venous return and thus in output per beat.
These suggest that funnel chest can affect cardiac function in different mechanisms.
4.Funnel chest and cardiopulmonary function
In recent decades, there has been an unending debate about whether the funnel chest deformity actually causes physical limitation in terms of pathophysiology. Some patients have complained clinically of shortness of breath and physical limitation, but these subjective symptoms are difficult to quantify objectively and have not shown any benefit from surgery in terms of the mechanisms that cause them. To this day, it remains unclear whether the initial pathophysiologic mechanism was altered ventilatory function or compression of the right ventricular outflow tract.
Initially, it was hypothesized that the funnel chest resulted in a reduction in lung volume that would improve after restoring the sternum to its normal position. In fact, however, pulmonary function tests generally show slight lung volume limitation, with total lung volume and exertional spirometry approaching 80% of the expected values. The ratio of 1st second exertional expiratory volume to exertional spirometry is generally normal. Lung volume testing up to 3 years after surgery showed the best results with a return to baseline lung volume, while some studies showed a 10% reduction from baseline levels, presumably related to reduced thoracic compliance. More complex studies have also not shown a significant increase in pulmonary functional reserve associated with symptom improvement.
However, the relationship between funnel chest and cardiorespiratory function remains a subject of debate. Despite conflicting findings, at least 60-70% of patients with symptoms of physical limitation experienced postoperative relief of subjective symptoms. Some studies showing satisfactory surgical outcomes also refute those who are skeptical of the importance of the pathophysiology of thoracic deformities, but subjective and objective factors in the evaluation of surgical outcomes make the results of these studies more confusing.
5.Pain
The cause of pain in patients with funnel chest is unclear and currently tends to be of musculoskeletal origin. The pectoralis major muscle arcs across the chest wall, starting at the level of the humerus and clavicle and ending at the parasternal area. In general, the muscle travels in a straight line, so the pain may originate from a slight tension generated by the curved course of the pectoralis major. Whether severe or not, the pain often occurs at rest and during running, and is not prolonged to the extent that treatment is required.
6. Behavioral manifestations
Finally, as the child enters school age, the appearance of thoracic deformity becomes the most common symptom. The child’s many embarrassing experiences eventually lead to significant behavioral changes.
Most children are reluctant to go swimming, will hide during gym class and bath time, and when participating in group competitions, such as splitting into top-wearing and non-top-wearing groups, they will often steadfastly choose to join the top-wearing group. These behaviors are apparently unrelated to the impaired physiological function that may result from a thoracic deformity, and thus there are many who believe that the deformity has no significant effect. However, when a 17-year-old student applied to college, the college application asked: What circumstances compelled you to deal with them mentally, physically and emotionally in a holistic manner? And how has it affected your life? The response to the question turned out to be related to his funnel chest, which was still untreated because his parents had been hesitant to operate. The psychological impact of the thoracic deformity is clearly illustrated in this response.
In the response, he described his experience of attending summer camp, when daily swimming routines became a nightmare for him, and was mercilessly laughed at and vilified by everyone, painful memories that stayed with him for many years. His pediatrician received a copy of this response and evaluated the emotional impact of the surgical scarring as well as the impact of the deformity itself. However, not all children with the condition will have the negative effects of the deformity.