Abstract Funnel is a congenital disorder in which the sternum, rib cartilage, and some of the ribs are deformed in a dorsal depression, forming a funnel shape. In the vast majority of funnel chests, the sternum starts at the level of the 2nd or 3rd rib cartilage and goes dorsally to the glabella forming a boat-like or funnel-like deformity, and its often a familial disorder. The funnel chest can cause the heart to be displaced by pressure and the lungs to be limited in movement due to the thoracic deformity, affecting the patient’s cardiopulmonary function. The symptoms become more pronounced after the age of 3 and should be treated early and actively. It is more common in males than females, and the ratio of male to female is reported to be 4:1, which is dominantly inherited. The incidence of funnel chest is 2.5% in those with a family history, while the incidence of funnel chest is only 1.0% in those without a family history. Funnel chest is a progressive lesion that may be present at birth, but often becomes more pronounced after a few months or even years and is detected by parents. The appearance of a funnel chest is characterized by a sunken anterior chest, anteriorly extended shoulders, a slightly hunched back, and a protruding upper abdomen. Funnel chest is a congenital condition in which the sternum, rib cartilage and some of the ribs are dorsally depressed and deformed to form a funnel shape.
In most cases, the sternum begins at the level of the 2nd or 3rd rib cartilage and moves dorsally to the saber to form a boat-like or funnel-like deformity, which is often a familial condition. The sternal body (especially the root of the saber process) and its corresponding 3rd to 6th ribs are sunken inward, resulting in a funnel-like anterior chest wall, which can cause the heart to be displaced by pressure and the lungs to be limited in movement due to the thoracic deformity, affecting the cardiopulmonary function of the child. The child may suffer from palpitations and shortness of breath after activity, and often develop upper respiratory tract and lung infections, and even heart failure. The symptoms of funnel chest become more obvious after the age of 3, with concave chest, convex belly, wasting and poor growth, which should be treated actively.
The principle of funnel chest deformity is not yet clear, but most people believe that funnel chest is due to excessive development and growth of rib cartilage and ribs in the lower chest, squeezing the sternum to shift, making it compensate for the inward concavity to form funnel chest. The sternal part of the diaphragm also develops too short, causing the sternum to compensate for the posterior displacement, which is also one of the possible causes of funnel chest formation.
Pathogenesis The deformity is often symmetrical in young patients with funnel chest, but gradually becomes asymmetrical with age, the sternum tends to rotate to the right side, the depression of the right rib cartilage tends to be deeper than the left side, the breast development on the right side is worse than the left side, the chest is more flat back or round back, the scoliosis gradually increases with age, the scoliosis is not obvious in infants and children, and the scoliosis is more obvious after puberty.
Clinical manifestations Funnel chest surgery treatment Funnel chest is more common in men than women, the ratio of men to women is 4:1, is a companion dominant inheritance under the age of 15 years old is common above the age of 40 years old is rare, this may be because of severe funnel chest and scoliosis compression of the heart and lungs, causing respiratory and circulatory failure, reduced lung capacity, increased functional residual air volume, reduced activity tolerance. Therefore, patients with severe disease tend to die before the age of 40; while patients with mild disease over the age of 40 are rarely seen.
Mild funnel chest can be asymptomatic, the deformity of the heavier compression of the heart and lungs, affecting respiratory and circulatory functions, young children often repeated respiratory infections, cough, fever, and less circulatory symptoms, older can appear after the activity of dyspnea, pulse fast palpitations and even precordial pain, which is due to heart compression, reduced myocardial hypoxia, etc.. Arrhythmias and systolic murmurs may also occur. Funnel chest is sometimes combined with pulmonary dysplasia, Mafang syndrome, asthma, and other diseases. The combination of these diseases often becomes an intolerable deformity and often requires early surgical correction.
Diagnosis of funnel chest includes 4 aspects: confirming the diagnosis, clarifying the degree, determining the presence of thoracic organ compression, and combining deformities. Funnel chest can be diagnosed immediately based on visual examination of the thorax, mostly from the 3rd rib to the 7th rib with inward depression and deformation, with the deepest depression above the sternal saber and the anterior end of the saber buckling anteriorly. The anterior part of the ribs slopes sharply downward from the posterior top, the upper and lower thorax becomes longer, and the distance between the anterior and posterior diameters shortens. In severe cases, the deepest depression of the lower part of the sternum can come in contact with the spine, and even reach the side of the spine to produce cardiopulmonary compression symptoms.
According to the extent of the anterior chest wall depression and thoracic deformity, there are four types of funnel chest: extensive, common, limited, mixed or irregular. Children with funnel chest commonly have bowed shoulders, a sunken anterior chest and a bulging abdomen, which are called “funnel chest signs”.
Degree judgment Funnel index: There are many clinical methods to determine the degree of funnel chest, and the funnel index (FI) is one of the methods to determine the degree of deformity. The analysis method is: severe: FI>0.3; moderate 0.3>FI>0.2; mild: FI<0.2. Funnel chest volume method: the patient supine, in the funnel chest depression inject warm water, and then use a syringe to draw out the fluid to measure the amount of water, which is also a way to determine the degree of funnel chest, must take into account the age, weight and height of the factors of severe patients can be up to about 200ml of water. Some people use the play-doh method to measure the same reason.
It uses light source and lattice projection method to take pictures of the corrugated contour image of the depressed part of the chest wall. Based on the interval and number of corrugated contour lines, the volume of the depressed part can be calculated by inputting it into the electronic computer through digital converter to determine the severity of the funnel deformity and to evaluate the effect of surgical treatment.
The lung lobes are seen to be narrow and the heart shadow is mostly displaced to the left with enhanced texture in the right lower lung lobe; the lower part of the sternum is seen to be depressed posteriorly in the lateral chest radiograph, near the spine or overlapping with it. The posterior part of the rib cage is flat and the anterior part is sharply inclined downward, and the right cardiac margin often overlaps with the spine There is a distinct radiolucent translucent area in the middle of the cardiac shadow. In individual patients with severe cases, the cardiac shadow can be located completely within the left thoracic cavity, and older patients have more scoliosis of the spine. In some cases, the lower end of the sternum can reach the anterior edge of the spine. CT examination can clearly show the degree of thoracic deformity and the displacement of the heart under pressure.
Treatment should be performed whenever there is a clear deformity. The younger the age, the smaller the scope of surgery and the better the result; while older children often need to remove bony ribs and often need blood transfusion.
There are three major types of surgery: sternal reversal, sternal lift, and complete thoracoscopic correction of funnel chest.
Sternal reversal
(1) Sternal reversal with upper and lower vessels and tipped sternum
A median skin incision in the chest and abdomen, or a transverse incision under the breast for female patients. The pectoralis major muscle on each side is freed laterally to reveal the sunken sternum and the deformed ribs and rib cartilage on both sides, and the rectus abdominis muscle is freed along the outer edge of the rectus abdominis muscle to the level of the umbilicus, and the attachment point of the rectus abdominis muscle on the rib cartilage and the glabella is preserved; the lower edge of the rib arch is cut, and the pleura on the inner surface of the sternum and the rib cartilage on both sides is freed with fingers to the outer side of the sunken deformity, and the 7th rib to the 3rd rib cartilage and the intercostal muscle are cut from the beginning of the deformed rib cartilage on both sides. The intercostal muscles were separated at the level of the 2nd intercostal space, and the intra-thoracic arteries on both sides were freed 4 to 5 cm up and down, and the intercostal vessels were contraindicated by electrocoagulation. The sternum is transected at this level with a wire saw, so that the depressed sternum and both sides of the rib cartilage are completely free and then the pectoral plate and rib cartilage are crossed with the intrathoracic artery and rectus abdominis muscle.
The sternum can be trimmed appropriately to flatten the sternum and avoid damaging the blood vessels in the sternum after the sternum is turned over and the most depressed part becomes the most prominent part. The transverse sternal break ends are closed with stainless steel wire sutures, and each corresponding broken end of the costal cartilage and intercostal muscle is sutured with polyester sutures to remove the excessively long costal cartilage, so that the rib cartilage plate of the reversed sternum can be fixed in the original position very appropriately after fixation, a closed drainage tube is placed behind the sternum, and then the pectoralis major muscle, subcutaneous tissue and skin are sutured.
② Sternal reversal with rectus abdominis tissues
The difference between this method and the sternal reversal with upper and lower vascularization is that this method cuts off the arteries and veins in the thorax and retains only the rectus abdominis muscle as the source of blood supply. The operation is basically the same as the previous method except that the sternum is transected by ligating and cutting off the intra-thoracic artery, then the sternum is transected, the sternum and the rib cartilage plate are turned 180° with the rectus abdominis muscle tip, and the deformed sternal plate is trimmed and then sutured and fixed in the original position.
③Tipless sternotomy (Wada method)
Using a transverse incision in the middle of the sternum or under the bilateral mammary glands, the pectoralis major and rectus abdominis muscles are freed, the deformed sternum, rib cartilage and ribs are revealed, and the periosteum of the rib cartilage on both sides is incised sequentially from the rib arch upward at the slightly bony side of the site where the deformity begins to depress, and the rib cartilage is cut, and the rib cartilage and pectoralis muscle are peeled out from within the periosteum, and the sternum is transected at the upper intercostal area where the sternum is depressed downward, and some of the intercostal muscles that may be attached are intact and cut out. Soft tissues, etc. After rinsing with antibiotic solution, the sternal plate was fixed at the sternal stalk with a wire that was flipped 180°, the overlap rib cartilage was cut out, and then the muscle and skin were sutured with polyester sutures fixed at the corresponding rib site.
④Sternal reversal with overlap
In some patients with flattened or sunken upper chest, after the sternal plate is turned over, the front of the upper sternum is cut into a beveled shape and the periosteum in front of the sternal stalk is inserted so that part of the pectoral muscle overlaps and the sternal plate is moved upward, the overlapping sternum is fixed with wire sutures, the rib cartilage is closed with polyester sutures, and part of the overlong rib cartilage is also overlapped and closed so that the postoperative thoracic contour is more satisfactorily corrected. Sternal reversal surgery is more suitable for adult patients, because adult sternal elevation is difficult to rectify asymmetrical funnel chest, and sternal reversal surgery is performed by freeing the medial side of sternum through the saber process, freeing and cutting off the rib cartilage at the beginning of deformation, trying to preserve the surrounding collateral tissues and blood vessels, cutting off the sternum at the depression with a sternal saw, and taking out the rib cartilage together; removing the soft tissues on the cartilage plate of sternum and repairing the plate smoothly, then putting it back upside down, and sternum with The sternum was fixed with steel wire and the rib cartilage was overlapped with polyester suture; drainage was routinely placed behind the sternum.
Sternal lift method Sternal lift is also called Ravitch orthopedic surgery. The sternum below the 2nd rib can be lifted sufficiently free. A transverse osteotomy is made in the posterior plate of the upper part of the sternum where the depression begins, and the autogenous cuneiform bone is embedded and sutured in place; the 2nd rib cartilage is cut in an anterior-internal and posterior-external direction; the medial end of the rib cartilage on both sides is overlapped with the lateral end and sutured in place. Some scholars have improved on the principles of Ravitch orthopedic surgery, such as transection of the anterior plate of the sternum and reinforced internal fixation with metal titanium pieces, which have achieved excellent results. It is important to note that in children under 10 years of age, the sunken sternum can sometimes be lifted using only a thoracic rib lift, i.e., the combined force of upward pulling of the shortened 3-7 ribs by excision.
Completely thoracoscopic correction of funnel chest Completely thoracoscopic minimally invasive technique for the treatment of funnel chest, which involves making 2-3 (≈1.5 cm) small holes in the chest wall without severing the sternum and ribs. The procedure is suitable for patients with funnel chests ranging in age from 3 to 50 years old, as well as for patients who have failed to be treated with traditional surgery. The reduced incision area greatly reduces the incidence of complications; compared to traditional surgical treatment of funnel chest (such as sternal reversal) with an open chest, the use of only about 1.5 cm chest wall “incision” reduces the surgical damage during the procedure. The overall recovery time after surgery is greatly reduced for the patient.
However, doctors say that this type of surgery should be completed before the age of 12, and many patients delay treatment until they are almost adults, which not only increases pain but also affects the outcome of treatment. Prevention This disease is a familial dominant genetic disorder, and there are no effective preventive measures. For children with less severe thoracic deformities, preventive measures should be taken primarily to prevent secondary aggravation.