Recurrence of pectus excavatum in long-term follow-up after the Nuss procedure in young children based on the radiographic Haller index

A preliminary study on the normal values of the thoracic Haller index in children

OBJECTIVES

The Haller index (HI) is widely utilized as a quantitative indicator to assess the extent of the pectus excavatum (PE) deformity, which is the most common chest wall abnormality in children. Both preoperative correction planning and postoperative follow-up need to be based on the standard of normal thoracic growth and development. However, there is currently no established reference range for the HI in children. Consequently, the goal of this study was to conduct a preliminary investigation of normal HI values among children to understand thoracic developmental characteristics.

METHODS

Chest computed tomography images obtained from January 2012 to March 2022 were randomly selected from the imaging system of the Children's Hospital of Chongqing Medical University. We divided the images of children into a total of 19 groups: aged 0-3 months (1 group), 4-12 months (1 group) and 1 year to 17 years (17 groups), with 50 males and 50 females, totaling 100 children in each group. HI was measured in the plane where the lowest point of the anterior thoracic wall was located and statistically analysed using SPSS 26.0 software.

RESULTS

A total of 1900 patients were included in the study. Our results showed that HI, transverse diameter and anterior-posterior diameter were positively correlated with age (P < 0.05). Using age as the independent variable and HI as the dependent variable, the best-fit regression equations were HI-male = 2.047 * Age0.054(R2 = 0.276, P<0.0001) and HI-female = 2.045 * Age0.067(R2 = 0.398, P<0.0001). Males had significantly larger thoracic diameters than females, and there was little difference in the HI between the 2 sexes.

CONCLUSIONS

The HI rapidly increases during the neonatal period, slowly increases during infancy and stops increasing during puberty, with no significant differences between the sexes.

What Is the Appropriate Timing for Bar Removal After the Nuss Repair for Pectus Excavatum?

INTRODUCTION

The Nuss procedure for pectus excavatum requires that the sternal elevation be maintained by indwelling metal bars that are traditionally removed approximately 3 y after the repair.

METHODS

A retrospective cohort study was conducted of all patients who underwent primary Nuss repair from 2007 to 2018 in two institutions and had a follow-up of at least 24 mo. Pectus bars had been left in place beyond 3 y in patients concerned over possible recurrence after bar removal. Structured interviews were held to assess pain, chest tightness, or other discomfort, and any adverse events related to pectus bars. Results were compared between patients in whom pectus bars were removed after 3 y (standard group) and those in whom bars were left in place longer (extended bar duration group).

RESULTS

Two hundred and thirty-one patients (91% males, mean age 23.9 ± 8.3, mean Haller index 4.9 ± 2.3) were included. Bar duration was 30.6 ± 6.6 mo in the standard group (51 patients) versus 69.1 ± 26.3 mo in the extended group (180 patients). Some discomfort was reported by 81.6% in the standard group versus 62.9% in the extended group (P = 0.033), and discomfort occurring at least monthly or more often was only reported by 30% in the standard versus 30.3% in the extended group (P = 1.000). Quality of life improved in 92.6% of the standard group versus 94.7% of the extended group (P = 1.000). No significant adverse events were reported in either group.

CONCLUSIONS

Our data suggest that an extended bar duration after the Nuss repair may not cause any adverse event nor negatively affect quality of life.

Machine Learning: Using Xception, a Deep Convolutional Neural Network Architecture, to Implement Pectus Excavatum Diagnostic Tool from Frontal-View Chest X-rays

Pectus excavatum (PE), a chest-wall deformity that can compromise cardiopulmonary function, cannot be detected by a radiologist through frontal chest radiography without a lateral view or chest computed tomography. This study aims to train a convolutional neural network (CNN), a deep learning architecture with powerful image processing ability, for PE screening through frontal chest radiography, which is the most common imaging test in current hospital practice. Posteroanterior-view chest images of PE and normal patients were collected from our hospital to build the database. Among them, 80% were used as the training set used to train the established CNN algorithm, Xception, whereas the remaining 20% were a test set for model performance evaluation. The performance of our diagnostic artificial intelligence model ranged between 0.976–1 under the receiver operating characteristic curve. The test accuracy of the model reached 0.989, and the sensitivity and specificity were 96.66 and 96.64, respectively. Our study is the first to prove that a CNN can be trained as a diagnostic tool for PE using frontal chest X-rays, which is not possible by the human eye. It offers a convenient way to screen potential candidates for the surgical repair of PE, primarily using available image examinations.

Factors reducing psychological satisfaction after the Nuss procedure in pediatric patients

PURPOSE

We examined patient satisfaction with postoperative chest appearance after Nuss procedure and analyzed the factors for postoperative low satisfaction.

METHODS

We retrospectively reviewed data of 133 patients who underwent the Nuss procedure from 2000 to 2016. Their medical records, X-rays, and computed tomography scans were evaluated. Haller index and concave rate were used as objective indices of the deformity. The questionnaires were used to evaluate satisfaction with the chest appearance by a linear scale including five markers (1: dissatisfaction, 5: satisfaction). The patients were divided into two groups: the low satisfaction (score = 1, 2) and the high satisfaction (score = 3-5).

RESULTS

The median age during the Nuss procedure was 7.6 (interquartile range, 5.8-12.8) years. Out of 133, 65 patients replied, and the mean postoperative satisfaction score was 3.8 ± 0.2. Out of the 65 respondents, 16 patients (24.6%) were classified as low satisfaction group. Haller index and concave rate were significantly higher and the previous instances of chest operation history were more frequent in the low satisfaction group than in the high satisfaction group, although there was no significant intergroup difference in terms of the postoperative concave rate.

CONCLUSIONS

Severe deformity and previous chest operation history were considered to be factors for low satisfaction.

Complications following metal bar removal after Nuss repair are rare in a duocentric retrospective evaluation

PURPOSE

Minimally invasive pectus excavatum repair has gained widespread acceptance and its results and complications are well-described. However, there is a substantial debate on the risks and frequencies of complications following metal bar removal. We, therefore, aimed to analyse all complications that occurred during and after metal bar removal at our two paediatric surgical centres.

METHODS

Bar removal surgeries were identified via procedural codes and electronic records were reviewed using a pre-specified data extraction chart. Both intra- and postoperative complications were included and the latter scored according to Clavien-Dindo. We analysed the influence of the pre-specified potential predictors age, sex, and the number of implanted metal bars on the occurrence of complications using logistic regression.

RESULTS

We included 279 patients with a median age of 19 years (interquartile range 17-20 years). 15 patients experienced 17 complications. Of 11 postoperative complications, only an enlarging pleural effusion required a chest drain in local anaesthesia, resulting in a Claven-Dindo grade IIIa, whereas the remainder were classified as grade I. Neither age (adjusted odds ratio (aOR) 0.97, 95% confidence interval (CI) 0.84-1.13, P = 0.73), nor sex (aOR 0.88, 95% CI 0.19-4.07, P = 0.87) or the number of bars (aOR 0.64, 95% CI 0.15-2.71, P = 0.547) did influence the occurrence of complications.

CONCLUSION

Complications following metal bar removal were scarce in our duocentric retrospective series and usually of minor relevance. However, to address the perceived paucity of data on the frequency and severity of complications following metal bar removal, further studies, including large database research is necessary.

Comparison of the Standard vs. Thoracoscopic Extrapleural Modification of the Nuss Procedure—Two Centers’ Experiences

Pectus excavatum is the most common congenital anterior chest wall deformity, with an incidence of 1:400 to 1:1000. Surgical strategy has evolved with the revolutionary idea of Donald Nuss, who was a pioneer in the operative correction of this deformity using minimally invasive surgery. The aim of this paper is to compare the preliminary results of pectus excavatum repair in two University Centers with a moderate number of patients using the standard Nuss procedure and its modification, the extrapleural thoracoscopic approach. The statistical analysis showed no significant difference for the patient’s age (14.52 ± 3.70 vs. 14.57 ± 1.86; p = 0.95) and the CT Haller index (4.17 ± 1.58 vs. 3.78 ± 0.95; p = 0.32). A statistically significant difference was noted for the duration of a pectus bar implant (2.16 ± 0.24 vs. 2.48 ± 0.68; p = 0.03) between the Maribor and Novi Sad Center. We report 14 complications (28%), including dislocation of the pectus bar (10%), pleural effusion (8%), wound inflammation (6%), pericarditis (2%) and an allergic reaction to the pectus bar (2%). Standard and thoracoscopic extrapleural Nuss procedures are both safe and effective procedures used to correct a pectus excavatum deformity. The choice of surgical procedure should be made according to a surgeon’s reliability in performing a particular procedure. Our study found no advantages of one procedure over the other.

Minimally Invasive Modified Nuss Procedure for Repair of Pectus Excavatum in Pediatric Patients: Single-Centre Retrospective Observational Study

Background: The treatment of pectus excavatum can be conservative or surgical. The aim of this study was to determine the factors influencing the outcomes of treatment after a minimally invasive Nuss corrective surgery procedure in pediatric patients. Methods: A total of 30 patient who underwent a minimally invasive Nuss corrective procedure for pectus excavatum from 1 January 2014 to 31 December 2020 were included in thisretrospective study. The collected data included thepatient’s demographic characteristics (age, sex, height, weight, body mass index—BMI, Haller index), treatment outcomes (duration of surgery, length of hospital stay, intraoperative complications, early and late complications, postoperative analgesia), and overall patient and legal guardian satisfaction two years after the procedure. Results: A total of 22 male and 8 female patients were included in the study. The median age was 15 years (interquartile range—IQR 14, 16), and the median BMI was 18.5 kg/m2 (IQR 17.7, 20.4) and 18.2 kg/m2 (IQR 16.9, 18.6) for males and females, respectively. The median CT Haller index was 3.67 (IQR 3.48, 4.09) for male and 3.69 (IQR 3.45, 3.9) for female patients. The median surgery duration was 120 min (IQR 100, 130), and the median hospital stay length was 8.5 days (IQR 8, 9.75). Indications for surgery were psychological (47%), followed by respiratory (30%) and combined respiratory-cardiac (20%) and respiratory-psychological disorders (3%). Early complications were observed in 18 patients (60%), and late complications were observed in 7 patients (23.3%). Intraoperative complications were not recorded. The most common early complications were pneumothorax and subcutaneous emphysema (30%), while late complications included bar displacement (10%) and deformity recurrence (6.6%). Overall, the procedure was successful in 93.1% of patients. Upon arrival home, 22 patients (81.5%) used analgesics for at least one day, up to a maximum of six months. A total of 23 (76.7%) operated patients determined that the surgical procedure had excellent results (grade 5), 4 (13.3%) patients report a good result (grade 4), 1(3.3%) patient reported a mediocre result, and one patient (3.3%) reported a bad result (grades 3 and 2, respectively). Conclusion: The Nuss procedure is a safe and effective method for treating funnel chest in children and adolescents. It also providesexcellent cosmetic and aesthetic results as well as subjective satisfaction with the outcome of surgical treatment.

Analysis of chest wall elevation after the Nuss procedure using 3D body scanning technique in patients with pectus excavatum

PURPOSE

For the evaluation of the chest wall deformity, we adopted a non-invasive 3D body scanning system. The objective of this study is to evaluate surgical effect on the whole thorax using 3D scanning technique before and after Nuss procedure.

METHODS

We performed 3D body scanning using Structure Sensor (Occipital Inc, USA) in 11 symmetric patients (average age 13 ± 3.2) under general anesthesia before and after Nuss procedure. Using the scanned data, the improved chest wall was analyzed using 3D-Rugle (Medic Engineering, Japan) imaging software. Preoperative and postoperative 3D data were super-imposed and a thoracic elevating distance in the line of the axial and sagittal section through the deepest point was calculated. Pre- and postoperative external sternal angle (ESA) were calculated from the scanned data.

RESULTS

Mean thoracic elevation distance at the deepest point was 38.6 ± 6.1 mm and it was 28.4 ± 5.1 mm and 19.4 ± 4.9 mm at 4 cm and 8 cm cranial side, respectively. Average ESA improved from 3.9 ± 1.6 degrees to 15.0 ± 1.1 degrees after the operation.

CONCLUSION

Chest depression was effectively elevated 39 mm at the deepest point after Nuss procedure. An indirect elevation effect by pectus bars was found on the wide area of the anterior chest.

Anterior chest wall regression after Nuss bar removal in adult patients with pectus excavatum

OBJECTIVE

Pectus excavatum repair with the Nuss procedure can be successfully performed in adults. After removing the pectus bars, the anterior chest wall may regress to some degree. The purpose of this study was to clarify the amount of improvement and regression of the chest wall after bar removal.

METHODS

In 45 adult patients who underwent the Nuss procedure, the sternovertebral distance (SVD) on lateral chest X-ray was measured (A) before the Nuss procedure, (B) before bar removal, and (C) after bar removal. The average SVD was compared, and the difference between A and C suggesting final sternal elevation and B and C suggesting regression was calculated. The correlation between the duration of bar in situ and the amount of regression was analyzed.

RESULTS

The average period of bar in situ was 34.9 ± 5.0 (range 23-45) months. The average SVD-A, SVD-B, and SVD-C values were 58.9 ± 20.0, 89.3 ± 19.1, and 81.6 ± 20.1 mm, respectively, with significant differences among them. Final sternal elevation was 22.7 ± 17.4 mm, and average regression was 7.6 ± 8.6 mm. The correlation coefficient between the duration of bar in situ and the amount of regression was 0.119, suggesting no clear correlation.

CONCLUSIONS

In spite of some degree of chest wall regression after bar removal, the Nuss procedure was effective for adult patients with pectus excavatum. The period of bar in situ and chest wall regression had little correlation.