pectus excavatum pectus excavatum pectus excavatum is a structural deformity of the anterior thoracic wall in which the sternum and rib cage are shaped abnormally. this produces a caved-in or sunken appearance of the chest. it can either be present at birth or develop after puberty. pectus excavatumother namesfunnel chest, dented chest, sunken chest, concave chest, chest holean example of an extremely severe case of pectus excavatumspecialtyorthopedics pectus excavatum can impair cardiac and respiratory function and cause pain in the chest and back. people with the condition may experience severe negative psychosocial effects and avoid activities that expose the chest. signs and symptoms the hallmark of the condition is a sunken appearance of the sternum. the most common form is a cup-shaped concavity, involving the lower end of the sternum; a broader concavity involving the upper costal cartilages is possible. the lower-most ribs may protrude ("flared ribs"). pectus excavatum defects may be symmetric or asymmetric. people may also experience chest and back pain, which is usually of musculoskeletal origin. in mild cases, cardiorespiratory function is normal, although the heart can be displaced and/or rotated. in severe cases, the right atrium may be compressed, mitral valve prolapse may be present, and physical capability may be limited due to base lung capacity being decreased. psychological symptoms manifest with feelings of embarrassment, social anxiety, shame, limited capacity for activities and communication, negativity, intolerance, frustration, and even depression. causes researchers are unsure of the cause of pectus excavatum. some researchers take the stance that it is a congenital disorder (birth defect), but not genetic. others assume that there is some genetic component. a small sample size test found that in at least some cases, 37% of individuals have an affected first degree family member. as of 2012, a number of genetic markers for pectus excavatum had also been discovered. it was believed for decades that pectus excavatum is caused by an overgrowth of costal cartilage, however people with pectus excavatum actually tend to have shorter, not longer, costal cartilage relative to rib length. pectus excavatum can be present in other conditions too, including noonan syndrome, marfan syndrome and loeys–dietz syndrome as well as other connective tissue disorders such as ehlers–danlos syndrome. many children with spinal muscular atrophy develop pectus excavatum due to their diaphragmatic breathing. pathophysiology physiologically, increased pressure in utero, rickets and increased traction on the sternum due to abnormalities of the diaphragm have been postulated as specific mechanisms. because the heart is located behind the sternum, and because individuals with pectus excavatum have been shown to have visible deformities of the heart seen both on radiological imaging and after autopsies, it has been hypothesized that there is impairment of the function of the cardiovascular system in individuals with pectus excavatum. while some studies have demonstrated decreased cardiovascular function, no consensus has been reached based on newer physiological tests such as echocardiography of the presence or degree of impairment in cardiovascular function. however, a 2016 meta-analysis found significant evidence that surgical correction of pectus excavatum improves patient cardiac performance. diagnosis cross sectional scan of a chest with pectus excavatum pectus excavatum is initially suspected from visual examination of the anterior chest. auscultation of the chest can reveal displaced heart beat and valve prolapse. there can be a heart murmur occurring during systole caused by proximity between the sternum and the pulmonary artery. lung sounds are usually clear yet diminished due to decreased base lung capacity. many scales have been developed to determine the degree of deformity in the chest wall. most of these are variants on the distance between the sternum and the spine. one such index is the backer ratio which grades severity of deformity based on the ratio between the diameter of the vertebral body nearest to xiphosternal junction and the distance between the xiphosternal junction and the nearest vertebral body. more recently the haller index has been used based on ct scan measurements. an index over 3.25 is often defined as severe. the haller index is the ratio between the horizontal distance of the inside of the ribcage and the shortest distance between the vertebrae and sternum. pectus excavatum on pa chest radiograph with shift of heart shadow to the left and radioopacity of the right paracardiac lung field chest x-rays are also useful in the diagnosis. the chest x-ray in pectus excavatum can show an opacity in the right lung area that can be mistaken for an infiltrate (such as that seen with pneumonia). some studies also suggest that the haller index can be calculated based on chest x-ray as opposed to ct scanning in individuals who have no limitation in their function. pectus excavatum is differentiated from other disorders by a series of elimination of signs and symptoms. pectus carinatum is excluded by the simple observation of a collapsing of the sternum rather than a protrusion. kyphoscoliosis is excluded by diagnostic imaging of the spine, wherein pectus excavatum the spine usually appears normal in structure. treatment pectus excavatum requires no corrective procedures in mild cases. treatment of severe cases can involve either invasive or non-invasive techniques or a combination of both. before an operation proceeds several tests are usually performed. these include, but are not limited to, a ct scan, pulmonary function tests, and cardiology exams (such as auscultation and ecgs). after a ct scan is taken, the haller index is measured. the patient's haller is calculated by obtaining the ratio of the transverse diameter (the horizontal distance of the inside of the ribcage) and the anteroposterior diameter (the shortest distance between the vertebrae and sternum). a haller index of greater than 3.25 is generally considered severe, while normal chest has an index of 2.5. the cardiopulmonary tests are used to determine the lung capacity and to check for heart murmurs. conservative treatment the chest wall is elastic, gradually stiffening with age. non-surgical treatments have been developed that aim at gradually alleviating the pectus excavatum condition, making use of the elasticity of the chest wall, including the costal cartilages, in particular in young cases. exercise physical exercise has an important role in conservative pectus excavatum treatment though is not seen as a means to resolve the condition on its own. it is used in order to halt or slow the progression of mild or moderate excavatum conditions and as supplementary treatment to improve a poor posture, to prevent secondary complications, and to prevent relapse after treatment. exercises are aimed at improving posture, strengthening back and chest muscles, and enhancing exercise capacity, ideally also increasing chest expansion. pectus exercises include deep breathing and breath holding exercises, as well as strength training for the back and chest muscles. additionally, aerobic exercises to improve cardiopulmonary function are employed. vacuum bell vacuum bell for pectus excavatum treatment, with hand pump (left) and measuring rod (right) an alternative to surgery, the vacuum bell, was described in 2006; the procedure is also referred to as treatment by cup suction. it consists of a bowl shaped device which fits over the caved-in area; the air is then removed by the use of a hand pump. the vacuum created by this lifts the sternum upwards, lessening the severity of the deformity. it has been proposed as an alternative to surgery in less severe cases. once the defect visually disappears, two additional years of use of the vacuum bell is required to make what may be a permanent correction. the treatment, in combination with physiotherapy exercises, has been judged by some as "a promising useful alternative" to surgery provided the thorax is flexible; the duration of treatment that is required has been found to be "directly linked to age, severity and the frequency of use". long-term results are still lacking. a single-center study reported in the journal of pediatric surgery found that use of vacuum bell therapy resulted in an excellent correction in twenty percent of patients, but "is not a substitute for the nuss procedure which can achieve an excellent result in 90% of patients". variables predictive of an excellent outcome include age ≤ 11 years, chest wall depth ≤ 1.5 cm, chest wall flexibility, and vacuum bell use over 12 consecutive months. in an article by interactive cardiovascular and thoracic surgery, the results found that vacuum bell treatment is safe for correcting the deformity non-surgically. the treatment has been shown to have higher success rates in patients who present earlier, have a mild and/or symmetrical deformity, a flexible chest wall and lack of costal flaring. the vacuum bell can also be used in preparation to surgery. orthoses brazilian orthopedist sydney haje developed a non-surgical protocol for treating pectus carinatum as well as pectus excavatum. the method involves wearing a compressive orthosis and adhering to an exercise protocol. mild cases have also reportedly been treated with corset-like orthopedic support vests and exercise. thoracic surgery incentive spirometers deepen lung ventilation after surgery to avoid atelectasis there has been controversy as to the best surgical approach for correction of pectus excavatum. it is important for the surgeon to select the appropriate operative approach based on each individual's characteristics. surgical correction has been shown to repair any functional symptoms that may occur in the condition, such as respiratory problems or heart murmurs, provided that permanent damage has not already arisen from an extremely severe case. surgical correction of the pectus excavatum has been shown to significantly improve cardiovascular function; there is inconclusive evidence so far as to whether it might also improve pulmonary function. one of the most popular techniques for repair of pectus excavatum today is the minimally invasive operation, also known as mirpe or nuss technique. magnetic mini-mover procedure the magnetic mini-mover procedure (3mp) is a minimally invasive procedure used to correct pectus excavatum by using two magnets to realign the sternum with the rest of the chest and ribcage. one magnet is inserted 1 cm into the patient's body on the lower end of the sternum, the other is placed externally onto a custom fitted brace. these two magnets generate around 0.04 tesla (t) in order to slowly move the sternum outwards over a number of years. the maximum magnetic field that can be applied to the body safely is around 4 t, making this technique safe from a magnetic viewpoint. the 3mp technique's main advantages are that it is more cost-effective than major surgical approaches such as the nuss procedure and it is considerably less painful postoperatively. its effectiveness is limited to younger children in early- to mid-puberty because older individuals have less compliant (flexible) chest walls. one potential adverse interaction with other medical devices is possible inactivation of artificial pacemakers if present. ravitch technique 26-year-old male after modified-ravitch reconstructionthe visible surgical scar on the chest of a 23-year-old male, five years after a successful ravitch procedure the ravitch technique is an invasive surgery that was introduced in 1949 and developed in the 1950s. it involves creating an incision along the chest through which the cartilage is removed and the sternum detached. a small bar is inserted underneath the sternum to hold it up in the desired position. the bar is left implanted until the cartilage grows back, typically about six months. the bar is subsequently removed in a simple outpatient procedure; this technique is thus a two-stage procedure. the ravitch technique is not widely practiced because it is so invasive. it is more often used in older individuals, where the sternum has calcified when the deformity is asymmetrical, or when the less invasive nuss procedure has proven unsuccessful. nuss procedure main article: nuss procedure x-ray of a 15-year-old male after undergoing the nuss procedure in 1987, donald nuss, based at children's hospital of the king's daughters in norfolk, virginia, performed the first minimally invasive repair of pectus excavatum (mirpe) and presented it much later at a conference in 1997. his two-stage procedure, widely known as the nuss procedure, involves slipping in one or more concave steel bars into the chest, underneath the sternum. the bar is flipped to a convex position so as to push outward on the sternum, correcting the deformity. the bar usually stays in the body for about two years, although many surgeons are currently moving toward leaving them in for up to five years. when the bones have solidified into place, the bar is removed through outpatient surgery.