The treatment of pectus carinatum with the bracing after surgery for congenital heart disease: experience from a single institution

Purpose:Secondary pectus carinatum (PC) after surgery for congenital heart disease(CHD) has its own clinical characteristics.Conservative treatment of PC with bracing is an attractive alternative to surgical repair.This study was to investigate the effects of the bracing on treating pediatric patients with PC after heart surgery. Methods:We conducted a retrospective study of all patients who had PC after surgery for CHD with median sternotomy from March 2019 to December 2020.Monthly follow-up with anterior–posterior(AP) width measurements.The size of bracing is designed based on the patient’s anterior chest wall. Result:Twenty four patients (3/2019–12/2020) were conducted into this retrospective study in the clinic,and 22 patients(91.66%) achieved excellent correction.The twenty four patients were distributed into three stages(stage 1: treated for 0 month,stage 2:treated for 3 months, stage 3: treated for 6 months).We found statistically signicant differences in the AP between stage 2 and stage 1(AP p<0.01),stage 3 and stage 2(AP p<0.01).The main side effects were mild subcutaneous hematoma,petechial bleeding and chest tightness.There was no children complicated with hydropericardium or cardiac tamponade. Conclusion:The bracing has been shown to be a safe and effective approach for the treatment of the pediatric patients with PC after surgery for CHD.


Introduction
Sternotomy is usually used in surgery for CHD.The PC is characterized by protrusion of the sternum and costal cartilages.It is the second most common type of chest wall deformity. [i]Respiratory function tests show no signi cant pathological changes in these children.If accompanied by scoliosis, restricted respiratory dysfunction may be found. [ii] , [iii] Pediatric PC patients may have shortness of breath and symptoms of chest pain, especially during exercise. 1 In addition to the physical symptoms, the deformity can cause cosmetic and psychological problems.During adolescence, the deformity becomes more prominent as the growth rate increases.Some pediatric patients after surgery for CHD usually combined with PC.In the clinic we met some of these pediatric patients with PC secondary to CHD surgery( g.1).These pediatric patients are temporarily exempt from social and psychological problems.But their parents are very anxious about their chest wall deformity.As the children get older,they may have negative physical self-esteem and poor quality of life. [iv]Presumably, correcting their chest wall deformities improves self-esteem and con dence. [v]Until recently, corrective methods for patients with PC included aggressive surgical interventions in the form of open or modi ed Ravitch or minimally invasive procedures. [vi] , [vii] , [viii]Conservative treatment of PC avoids operative intervention and possible complications,has no scars,and cost less than surgery. 8, [ix]In many studies, bracing have had very satisfactory results in adolescents. 1,6,9, [x]But there is no study has examined the the effects of bracing on pediatric patients with PC after CHD surgery.The aim of this study was to examine the effectiveness of bracing to correct PC in pediatric patients secondary to CHD surgery.

Methods
The study was approved by the Medical Ethics Committee of Fujian Provincial Maternity and Children's Hospital(the date of IRB approval was April 06,2020, the IRB approval number is 2020-KY-039).All of our patients were under the age of 18 and we obtained informed consent from the parents.The method of treating for pectus carinatum with bracing is in accordance with guidelines published by the American Paediatric Surgical Association. [i] Patients We conducted a retrospective study of all patients who had PC after surgery for CHD with median sternotomy from March 2019 to December 2020.The exclusion criteria were as following: having a chronic systemic disease, having complex and mixed type chest wall deformity and being unwilling to use orthosis.The indications for intervention with a bracing were as such:failure to meet the operative criteria,being unwilling to surgery,being compression test positive, and having a pressure of correction under 10 per square inch.At the clinic, patients had the option to undergo surgery or bracing therapy.And most of them preferred to chose the conservative treatment.Echocardiograph coagulation function and electrocardiograph was routinely performed before the daily application of the bracing to evaluate the patient and exclude cardiac insu ciency.Data collected included the patient's age, height, weight,chest wall measurements, associated features, associated symptoms and medical history.Patient characteristics are shown in table 1.All pediatric patients should be supervised by caregivers at home.Compliance is the key to permanent correction of the pectus carinatum deformity.
Patients wore a snug tting undershirt under the bracing ( g.2) at all times to prevent skin breakdown.Within the rst week, bracing was used for at least 2h a day to increase the tolerance of the chest wall.The use time was gradually increased to 8h a day at week 2 and increased to 23h a day in one month. Patients should be followed up every 3 months according to the schedule.Using bracing for the rst time, the patients should be kept in the clinic and observed for at least half an hour.The pressure for initial correction was measured in all patients.We recorded the pressure of bracing.We tried to atten the protrusion of the sternum and costal cartilages at the rst time when the patients' parents decided to start the treatment.If there was chest pain,chest tightness, palpitations or other persistent symptoms,we reduced the pressure.
Because of the outbreak of novel coronavirus 2019,many patients faced travel restrictions.Patients should be continued to be followed to ensure that their chest remains at.For those patients who had not returned the clinic after 3 months, we contacted them by WeChat(a popular Chinese mobile messenger app).With the help of WeChat,we could communicate with parents more easily and often.
Every time the bracing was adjusted, it should be monitored by the outpatient doctor, and gradually increased the pressure to atten the protrusion according to the tolerance of the children.If there was chest pain,chest tightness, palpitations or other symptoms, we stopped the treatment immediately.It should be alert for heart damage.Echocardiography could help us to diagnose.Reducing the pressure and the using time could help most of the patients to continue the treatment.

Statistics
Statistical analysis was performed by using SPSS Statistics(version 25,SPSS Inc., IBM Company,Chicago,IL).The AP at 0 month,3 months,6 months were compared by the Friedman rank test, and the differences in the improvements among patients with different ages,sex,or symmetry classi cations were compared by the Mann-Whitey U test.A p value less than 0.05 was considered statistically signi cant.

Discussion
The pediatric patients included in this study underwent median sternotomy after heart surgery had its own clinical characteristics.First,patients' chest wall is exible.We could use less pressure to atten the raised sternum.Second,steel wire was used to suture the sternum after heart surgery.At the end of an operation, the sternal wires are tightened by twisting the two ends together, and then the wires are bent over such that the tips of the wires are directed away from the skin.We could palpable xation wire locally on the chest wall for some patients.In the process of brace compression,the wire increased skin wear, resulting in local skin swelling, bleeding, pain and other complications.Third,the patients had surgical scars on the anterior median chest wall.Some children were with scar constitution (Fig 3).In the process of brace pressure,the scar were tougher than the surrounding tissue, which would increase the discomfort of children and reduce compliance.These patients were more easily to make skin damage and even bleeding during brace compression.
Our aim is to learn the effects of bracing in the treatment of those patients with PC after CHD surgery.The effect of steel wire on the formation of PC patients remains to be further studied.Whether removing the steel wire has positive effects on the treatment of PC remained to be demonstrated.Because our young patients' chest wall are exible,these pediatric patients may require longer periods of maintenance bracing.We advise these patients to brace for a few hours a day after achieving satisfactory outcome.
Echo tests show heart compression and strain in patients with PE, potentially warranting surgical repair with the Nuss procedure. [i] , [ii] Because PC is not physically compressing the chest, cardiac evaluation is infrequently considered.However, in this study we also payed attention to the effects of braces on cardiac function.All the 24 children included in the study were regularly followed up by outpatient cardiac surgeons after heart surgery.Reexamination of echocardiography and electrocardiogram showed that the heart function were well.
In 2 cases,subcutaneous xed wire in the middle of the anterior chest wall protrusion were obvious.We could palpate the wire clearly.Therefore, during brace treatment,we intentionally added a small pad to reduce friction and avoid skin lesions.
Surgical scars were obvious in the middle of chest wall in 5 patients.In the process of brace treatment,we also added a small piece of cotton pad to the scar to reduce friction and avoid skin lesions.Due to the presence of scar,the anterior chest wall discomfort was more obvious at the beginning of brace therapy in these children.However,after 1 month of adaptation,the scar became atter and the children gradually tolerated the brace therapy.
We generally recommend that children start brace therapy when the weather is cool. So the children will wear more clothes.This can reduce skin problems caused by excessive sweating in children.At the same time, the cotton-padded clothes under the support can better protect the skin of children. In summer,because of the hot weather,we advised that children wear braces and stay in an air-conditioned room.
Kravarusic et al 11 reported signi cant improvement in subjective appearance was observed in patients who wore a compression orthosis for 23 hours daily.Colazza et al [iii] detected that the patients were satis ed with the chest wall appearance after bracing treatment and their self-esteem increased.In another study,Thaker et al [iv] investigated patients perception via a nonstandardized questionnaire.They concluded that patients improved self-esteem and satisfaction with their chest wall chest wall appearance.Sesia et al [v] advised that the lateral expansion of the chest should be always considered, allowing breathing and chest expansion due to AP compression forces and natural growth.
In addition to orthosis, exercise should also be carried out to provide a better correction of the deformity of PC patients.If the bracing treatment fails, surgical repair is still a good choice. [vi]Surgical correction is often used in the most severe cases.Patients with mild or moderate PC are usually do not undergo surgical correction. [vii]Lee et al reported that skeletal maturity affects the correction of the deformity. [viii]Emil et al [ix] reported that older age, asymmetry and smaller rst drop in pressure of treatment was associated with failure and longer orthosis use.

Limitations
This study has the following limitations.First the compliance of the pediatric patients and the parents are different.Second,AP may be in uenced by fat thickness during the scanning process.Factors that may the noninvasive, minimal discomfort and high patient satisfactions,we believe that bracing treatment is an effective rst-line treatment for many PC patients after CHD.

Supplementary Files
This is a list of supplementary les associated with this preprint. Click to download. le.doc