New Computerized Planning Algorithm and Clinical Testing of Optimized Nuss Bar Design for Patients with Pectus Excavatum

BACKGROUND Computer-aided design (CAD) has been used in the Nuss procedure to determine the bar length and shape. Despite computer aid, the shape and design remain quite intuitive. We tested a new algorithm to determine the optimal bar shape. MATERIAL AND METHODS The normal sterno-vertebral distance was defined on computed tomography (CT) scans of patients without pectus excavatum (PEx) at the same level where the deepest depression was found on CT scans of 97 patients with PEx. Four points were marked on the CT scan of 60 patients with PEx at the deepest deformity: P1: edge of the vertebra; P2: edge of the deformity; P3: the expected contact point of the bar and the rib; and P4: the expected end of the bar. The algorithm generated 3 circles upon these points, and the fusion of the arcs drew the line of the ideal bar. Corrected and normal sterno-vertebral distance values were compared with the Mann-Whitney U test. Ten bars were bent manually guided by a 1: 1 printout of the designed bar and were implanted in 10 adolescents. RESULTS The shortest sterno-vertebral distance was 3 cm below the intermammillary line in PEx patients. The normal mean sterno-vertebral distance at this level was 10.16±1.35 cm in non-PEx patients. The mean virtually corrected sterno-vertebral distance was 10.28±1.27 cm. No significant difference was found (P=0.44). The bars were seamless and were successfully implanted. No bar needed adjustment, the operation time was shorter, and the patient satisfaction score was 9.4/10. CONCLUSIONS With our new algorithm, an optimal Nuss bar can be designed.

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.

Sternal cleft and pectus excavatum: an overlooked congenital association?

BACKGROUND

Sternal cleft (SC), a rare thoracic malformation, is associated with pectus excavatum (PE) in 2.6-5% of cases. It remains unclear if these conditions are congenitally linked or if SC repair triggers PE. To investigate the potential higher frequency of PE in SC cases, we conducted a retrospective study of our SC patients.

METHODS

We assessed PE incidence, progression, and management in SC patients treated at our institute from 2006 to 2022. When available, we collected pre-SC repair CT scan data, calculating the Haller Index (HI) and Correction Index (CI) and compared them to a selected control group.

RESULTS

Among 8 SC patients, 7 had concomitant PE (87.5%), varying in severity. PE management ranged from observation to thoracoplasty, depending on its degree. We observed a significant pre-operative CI difference between SC and control group patients (p < 0.00001). In the last two SC repair cases, we attempted concurrent PE prevention or treatment.

CONCLUSION

Our findings suggest an underestimated association between PE and SC in the existing literature. SC patients may exhibit a predisposition to PE from birth, which may become more apparent with growth after SC repair. Consequently, PE prevention or treatment should be considered during SC repair procedures.

Evaluating Skeletal Maturity at Time of Surgical Correction of Pectus Excavatum Based on Medial Clavicle Epiphyseal Ossification

BACKGROUND

Surgical correction of pectus excavatum (SCOPE) is dependent upon chest wall pliability with optimal timing prior to complete skeletal maturation. Measures of skeletal maturity are not readily available for operative planning; therefore, surgeons use age as proxy despite patient-specific rates of skeletal maturation. We aimed to determine whether preoperative skeletal maturity is associated with postoperative pain as surrogate for chest wall pliability.

METHODS

Children ≤18 years who underwent SCOPE from 2020 to 2022 were retrospectively identified. Preoperative CT within 3 months of procedure was reviewed by 2 radiologists and 1 surgeon. Skeletal maturity was determined by Schmeling-Kellinghaus classification which stages secondary epiphyseal ossification of the medial clavicle. Inter-rater reliability was evaluated. Schmeling-Kellinghaus stage and postoperative pain were compared.

RESULTS

Of twenty-eight records reviewed, 57% were Schmeling-Kellinghaus stage 1. High inter-rater reliability was identified (inter-radiologist: kappa = .95, P < .001, all raters: kappa = .78, P < .001). Median age at operation was 15.5 years (interquartile range: 14.8-16.0) and increased with skeletal maturity (P < .001). When comparing stage 1 (n = 16) to >1 (n = 12), stage 1 had lower maximum pain scores (P < .001), total morphine equivalents (P < .001), and benzodiazepine use (P < .001) after surgery.

CONCLUSIONS

The Schmeling-Kellinghaus classification system is a valid proxy of skeletal maturity that can be applied with high inter-rater reliability. SCOPE during stage 1 was found to have less postoperative pain and narcotic use than more mature stages. This is proof of concept that skeletal maturity should be considered when determining optimal timing of surgical correction. Future research will evaluate the impact of skeletal maturity on postoperative outcomes.

Use of Transesophageal Echocardiography for Enhanced Safety During Bar Removal Procedures After Minimally Invasive Repair of Pectus Excavatum

Background: Minimally invasive repair of pectus excavatum involves placement of retrosternal support (Nuss) bars. Hardware removal has been rarely associated with life-threatening hemorrhage from the heart, aorta, internal mammary arteries, and/or lung. There is no accepted standard intraoperative monitoring technique used during removal. We hypothesized that the use of transesophageal echocardiography (TEE) during Nuss bar removal would enhance safety of the procedure and be cost-effective. Methods: IRB-approved retrospective review of patients who underwent Nuss bar removal with intraoperative TEE monitoring over a 4-year period, from March 2013 to May 2017, was completed. Bar removal procedures were performed supine, under general anesthesia. TEE images were monitored and any distortion of the cardiac silhouette, new pericardial effusion, and/or cardiac arrhythmias would be considered evidence of possible bar adherence, triggering possible conversion to sternotomy or thoracotomy. Results: In total, 87 consecutive patients, mean age of 20 years, were identified. Bars had been in place for a mean of 30 months. Average procedure time was 67 minutes. No patients experienced arrhythmias, cardiac injury, or significant hemorrhage during removal. TEE gave excellent visualization of the cardiac silhouette and pericardium in all cases. No patient required insertion of an arterial line, a postoperative chest X-ray, or overnight hospitalization. Patients were discharged from the recovery room an average of 89 minutes postprocedure. Conclusion: TEE offers a minimally invasive safe way to visualize the pericardium and its contents during Nuss bar removal. Significant cardiac/mediastinal injuries should be immediately visible. The use of TEE is cost-effective and allows safe discharge the day of surgery.

A novel in silico Nuss procedure for pectus excavatum patients

The purpose of this study is to suggest a novel in silico Nuss procedure that can predict the results of chest wall deformity correction. Three-dimensional (3D) geometric and finite element model of the chest wall were built from the 15-year-old male adolescent patient's computed tomography (CT) image with pectus excavatum of the mild deformity. A simulation of anterior translating the metal bar (T) and a simulation of maintaining equilibrium after 180-degree rotation (RE) were performed respectively. A RE simulation using the chest wall finite element model with intercostal muscles (REM) was also performed. Finally, the quantitative results of each in silico Nuss procedure were compared with those of postoperative patient. Furthermore, various mechanical indicators were compared between simulations. This confirmed that the REM simulation results were most similar to the actual patient's results. Through two clinical indicators that can be compared with postoperative patient and mechanical indicators, the authors consider that the REM of silico Nuss procedure proposed in this study is best simulated the actual surgery.

Pectus Arcuatum: A Pectus Unlike Any Other

BACKGROUND

Pectus arcuatum is often mistaken for a type of pectus carinatum. However, pectus arcuatum is a unique clinical form of pectus caused by premature obliteration of the sternal sutures (manubrial sternum, four sternebrae and xiphoïd process), whereas pectus carinatum is due to abnormal growth of the costal cartilage. In order to better describe pectus arcuatum, we analysed the files of patients with pectus arcuatum followed in our centers.

METHODS

Multicenter retrospective study of young patients' files diagnosed with pectus arcuatum.

RESULTS

The clinical diagnosis of pectus arcuatum was made in 34 patients with a mean age at diagnosis of 10.3 years (4-23 years). A chest profile X-ray or a CT scan was performed in 16 patients (47%) and confirmed the diagnosis of PA by the presence of a sternal fusion. It was complete in 12 patients. A malformation was associated in 35% of cases (Noonan syndrome 33%, scoliosis 25% or cardiopathy 16%). 11 patients (32%) had a family history of skeletal malformation. Orthopedic treatment was initiated in 3 patients without any success. 11 patients underwent surgical correction, which was completed in 7 of them.

CONCLUSION

The diagnosis of pectus arcuatum is based on clinical experience and if necessary, on a profile chest X-ray showing the fusion of the sternal pieces. It implies the search for any associated malformations (musculoskeletal, cardiac, syndromic). Bracing treatment is useless for pectus arcuatum. Corrective surgery, based on a sternotomy associated with a partial chondro-costal resection, can be performed at the end of growth.

LEVEL OF EVIDENCE

IV.

Pectus excavatum in motion: dynamic evaluation using real-time MRI

OBJECTIVES

The breathing phase for the determination of thoracic indices in patients with pectus excavatum is not standardized. The aim of this study was to identify the best period for reliable assessments of morphologic indices by dynamic observations of the chest wall using real-time MRI.

METHODS

In this prospective study, patients with pectus excavatum underwent morphologic evaluation by real-time MRI at 3 T between January 2020 and June 2021. The Haller index (HI), correction index (CI), modified asymmetry index (AI), and modified eccentricity index (EI) were determined during free, quiet, and forced breathing respectively. Breathing-related differences in the thoracic indices were analyzed with the Wilcoxon signed-rank test. Motion of the anterior chest wall was analyzed as well.

RESULTS

A total of 56 patients (11 females and 45 males, median age 15.4 years, interquartile range 14.3-16.9) were included. In quiet expiration, the median HI in the cohort equaled 5.7 (4.5-7.2). The median absolute differences (Δ) in the thoracic indices between peak inspiration and peak expiration were ΔHI = 1.1 (0.7-1.6, p < .001), ΔCI = 4.8% (1.3-7.5%, p < .001), ΔAI = 3.0% (1.0-5.0%, p < .001), and ΔEI = 8.0% (3.0-14.0%, p < .05). The indices varied significantly during different inspiratory phases, but not during expiration (p > .05 each). Furthermore, the dynamic evaluation revealed three distinctive movement patterns of the funnel chest.

CONCLUSIONS

Real-time MRI reveals patterns of chest wall motion and indicate that thoracic indices of pectus excavatum should be assessed in the end-expiratory phase of quiet expiration.

KEY POINTS

• The thoracic indices in patients with pectus excavatum depend on the breathing phase. • Quiet expiration represents the best breathing phase for determining thoracic indices. • Real-time MRI can identify different chest wall motion patterns in pectus excavatum.

Stiffness reduction of the rib cage to perform a minimally invasive pectus excavatum repair: biomechanical evaluation

OBJECTIVES

To study the influence of sternal transection and costal chondrotomies on the stiffness and stresses in the rib cage of adult patients undergoing Nuss pectus excavatum procedure.

METHODS

Four pectus excavatum models with different Haller indexes were created by parameterizing a 3D model of a rib cage obtained based on a computed tomography scan of a patient with no pectus deformity. Using the finite element method, insertion of intrathoracic bars into all models was simulated in 3 conditions, namely, non-intervened, transverse sternal section and costal chondrotomies. Stiffness, stress distribution and maximum stresses for each case were obtained and compared.

RESULTS

Transverse sternotomy provided a reduction of 44% to 54% in the stiffness of the rib cage, depending on the Haller index analysed, while chondrotomies promoted a stiffness reduction of 70%. Stress distribution in the rib cage followed similar pattern for all the tested Haller index, but the maximum stress decreased by 36% when performing a transverse sternotomy, whereas when performing costal chondrotomies, it decreased by 47%.

CONCLUSIONS

Computational results report that transverse sternotomy reduces appreciably the stiffness of the rib cage, while costal chondrotomies promote even a higher stiffness reduction. Thus, these surgical procedures could improve the clinical outcomes of adult patients undergoing a pectus excavatum repair.

Prevalence and prognosis of pericardial effusion in patients affected by pectus excavatum: A case-control study

BACKGROUND

The presence of pectus excavatum(PEX) has been occasionally associated with pericardial effusion. Aim of the present study was to compare incidence and prognosis of pericardial effusion in a group of unselected patients with PEX vs a control group.

METHODS

From a prospective registry of consecutive patients who underwent chest CT for cardiovascular disease, subjects with a radiological diagnosis of PEX were retrospectively identified (cases); from the same registry patients (controls) without rib cage abnormalities were randomly selected, until a 1:2 ratio was reached. The presence of pericardial effusion at CT was quantified. Follow-up was obtained for a composite end-point: cardiac tamponade, need for pericardiocentesis, need for cardiac surgery for relapsing pericardial effusion.

RESULTS

A total of 43 patients with PEX (20 females) and a control group of 86 cases (31 females) without rib cage abnormalities were identified. Pericardial effusion evaluated at CT was significatively more prevalent in patients with PEX vs control group, 37.2% vs 13.9% (p < 0.001), respectively; four patients with PEX (9.3%) had at least moderate pericardial effusion vs no subjects among the controls (p = 0.004). PEX diagnosis was significantly associated to pericardial effusion at multi-variate analysis (OR95%CI 10.91[3.47-34.29], p < 0.001). At a mean follow-up of 6.5 ± 3.4 years no pericardial events were recorded.

CONCLUSION

Our findings support the higher prevalence of pericardial effusion in patients with PEX when compared to a control group. The absence of adverse pericardial events at follow-up suggest the good prognosis of these effusions, that in the appropriate clinical setting might not be considered "idiopathic".

Customized Two-Dimensional Computed Tomography-Guided Preoperative Pectus Bar Shaping

INTRODUCTION

Successful minimally invasive repair of pectus excavatum relies on a pectus bar that closely conforms to the desired shape of the sternum and ribs to produce optimal elevation and remodeling. However, the present method of empirical intraoperative bar shaping is tedious and risks trauma to surrounding structures. To overcome this, we devised a technique using a life-sized computed tomography (CT) printout of the patient's chest wall to guide preoperative bar bending.

METHODS

A 5-cm-wide polymethylmethacrylate block placed on the sternum as the patient underwent chest CT was used as a marker to guide scaling of an axial screenshot of the patient's chest to life-size. This life-size image was printed and the planned correction of the patient's chest wall was traced onto it. The pectus bar was bent according to this template. Patient demographics, Haller index, surgical indications, operative technique, complications, aesthetic and functional improvements, and overall satisfaction were assessed.

RESULTS

Thirty patients (4 women) underwent primary minimally invasive repair of pectus excavatum with a single pectus bar shaped preoperatively over an 8-year period. The average age and Haller index was 20.6 years and 5.4, respectively. The mean operative time was 66.4 minutes. Satisfactory sternal elevation was attained with a single attempt at bar insertion in all cases. Two patients had pneumothoraxes that resolved without intervention. The mean follow-up period was 50.1 months. There were no cases of bar migration or recurrence of deformity after bar removal. On a 5-point Likert scale, all patients indicated an improvement in aesthetic appearance (4.6), and patients with physical symptoms (10) reported an improvement in function (4.4). The overall satisfaction score was 4.7.

CONCLUSIONS

This technique of CT-guided preoperative pectus bar shaping is straightforward, eliminates the need for intraoperative revisions to bar shape, and achieves effective correction of the pectus excavatum deformity. All patients were satisfied with the aesthetic, functional, and overall outcomes.

What Can Proton Beam Therapy Achieve for Patients with Pectus Excavatum Requiring Left Breast, Axilla and Internal Mammary Nodal Radiotherapy?

AIMS

Exposure of the heart to radiation increases the risk of ischaemic heart disease, proportionate to the mean heart dose (MHD). Radiotherapy techniques including proton beam therapy (PBT) can reduce MHD. The aims of this study were to quantify the MHD reduction achievable by PBT compared with volumetric modulated arc therapy in breath hold (VMAT-BH) in patients with pectus excavatum (PEx), to identify an anatomical metric from a computed tomography scan that might indicate which patients will achieve the greatest MHD reductions from PBT.

MATERIALS AND METHODS

Sixteen patients with PEx (Haller Index ≥2.7) were identified from radiotherapy planning computed tomography images. Left breast/chest wall, axilla (I-IV) and internal mammary node (IMN) volumes were delineated. VMAT and PBT plans were prepared, all satisfying target coverage constraints. Signed-rank comparisons of techniques were undertaken for the mean dose to the heart, ipsilateral lung and contralateral breast. Spearman's rho correlations were calculated for anatomical metrics against MHD reduction achieved by PBT.

RESULTS

The mean MHD for VMAT-BH plans was 4.1 Gy compared with 0.7 Gy for PBT plans. PBT reduced MHD by an average of 3.4 Gy (range 2.8-4.4 Gy) compared with VMAT-BH (P < 0.001). PBT significantly reduced the mean dose to the ipsilateral lung (4.7 Gy, P < 0.001) and contralateral breast (2.7 Gy, P < 0.001). The distance (mm) at the most inferomedial extent of IMN volume (IMN to heart distance) negatively correlated with MHD reduction achieved by PBT (Spearman's rho -0.88 (95% confidence interval -0.96 to -0.67, P < 0.001)).

CONCLUSION

For patients with PEx requiring left-sided breast and IMN radiotherapy, a clinically significant MHD reduction is achievable using PBT, compared with the optimal photon technique (VMAT-BH). This is a patient group in whom PBT could have the greatest benefit.

Does chest wall conformation influence myocardial strain parameters in infants with pectus excavatum?

PURPOSE

To investigate the possible influence of chest wall conformation on myocardial strain parameters in a consecutive population of infants with pectus excavatum (PE), noninvasively assessed by modified Haller index (MHI).

METHODS

Sixteen consecutive PE infants (MHI >2.5) and 44 infants with normal chest shape (MHI ≤2.5) entered in this prospective case-control study. All infants underwent evaluation by neonatologist, transthoracic echocardiography implemented with two-dimensional speckle tracking echocardiography (2D-STE) analysis of both ventricles and MHI assessment (ratio of chest transverse diameter over the distance between sternum and spine), at two time points: within 3 days and at about 40 days of life.

RESULTS

At 2.1 ± 1 days of life, compared to controls (MHI = 2.01 ± 0.2), PE infants (MHI = 2.76 ± 0.2) were diagnosed with significantly smaller cardiac chambers dimensions. Biventricular contractile function and hemodynamics were similar in both groups of infants. Left ventricular (LV) global longitudinal strain (GLS) (-16.0 ± 2.8 vs. -21.7 ± 2.2%), LV-global circumferential strain (GCS) (-16.3 ± 2.7 vs. -24.0 ± 5.2%), LV-global radial strain (GRS) (24.2 ± 3.0 vs. 31.5 ± 6.3%), and right ventricular free wall longitudinal strain (RVFWLS) (-16.0 ± 3.2 vs. -22.3 ± 4.4%) were significantly reduced in PE infants versus controls (all p < 0.001). A strong inverse correlation between MHI and the following parameters: LV-GLS (r = -0.92), LV-GCS (r = -0.88), LV-GRS (r = -0.87), and RVFWLS (r = -0.88), was demonstrated in PE infants, but not in controls, in perinatal period (all p < 0.001). Analogous results were obtained at 36.8 ± 5.2 days after birth.

CONCLUSIONS

Abnormal chest anatomy progressively impairs myocardial strain parameters in PE infants. This impairment might reflect intraventricular dyssynchrony due to compressive phenomena rather than intrinsic myocardial dysfunction.

Presumed acquired dynamic pectus excavatum in a cat

An 11-year-old, spayed female American domestic shorthair cat was presented with open-mouth breathing and dyspnea due to respiratory tract disease. Radiographically, there was thickening of the retropharyngeal soft tissue and soft palate, focal pulmonary change, and severe pectus excavatum (PE), best seen on the left lateral view. Repeat thoracic radiographs 4 months later showed persistent PE, but only on the right lateral view; PE was absent on the left lateral view. The dynamic component of the observed PE was presumably acquired secondary to chronic upper respiratory disease and/or concurrent increased pliability of the thoracic wall from prolonged prednisolone treatment.

Automatic assessment of Pectus Excavatum severity from CT images using deep learning

Pectus excavatum (PE) is the most common abnormality of the thoracic cage, whose severity is evaluated by extracting three indices (Haller, correction and asymmetry) from computed tomography (CT) images. To date, this analysis is performed manually, which is tedious and prone to variability. In this paper, a fully automatic framework for PE severity quantification from CT images is proposed, comprising three steps: (1) identification of the sternue's greatest depression point; (2) detection of 8 anatomical keypoints relevant for severity assessment; and (3) measurements' geometric regularization and extraction. The first two steps rely on heatmap regression networks based on the Unet++ architecture, including a novel variant adapted to predict 1D confidence maps. The framework was evaluated on a database with 269 CTs. For comparative purposes, intra-observer, inter-observer and intra-patient variability of the estimated indices were analyzed in a subset of patients. The developed system showed a good agreement with the manual approach (a mean relative absolute error of 4.41%, 5.22% and 1.86% for the Haller, correction, and asymmetry indices, respectively), with limits of agreement comparable to the inter-observer variability. In the intrapatient analysis, the proposed framework outperformed the expert, showing a higher reproducibility between indices extracted from distinct CTs of the same patient. Overall, these results support the feasibility of the developed framework for the automatic, accurate and reproducible quantification of PE severity in a clinical context.

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

BACKGROUND/PURPOSE

To show the changes of the thorax after bar removal in young children with pectus excavatum in long-term postoperative follow-up.

METHODS

A total of 173 patients who underwent Nuss procedure under the age of 10 years from January 2005 to December 2013 and underwent bar removal were retrospectively reviewed. Then, Patients who were followed-up for more than 5 years after bar removal were selected and assessed. All patients were evaluated with the Haller index (HI) by chest computed tomography before the Nuss procedure. Follow-up after bar removal was done by two-view radiography. Radiographic HI (rHI) change was evaluated from before bar removal, to immediately after bar removal, and 3 years and 5 years after bar removal.

RESULTS

Forty-two patients (35 boys, 7 girls) were followed-up for more than 5 years after bar removal. The average age at the Nuss procedure was 6.1 ± 1.3 years, and the average HI was 5.07 ± 1.54. The average age at bar removal was 8.5 ± 1.2 years. The average rHI was 2.47 ± 0.33 before bar removal, 2.75 ± 0.50 immediately after bar removal, 3.24 ± 0.64 at 3 years after bar removal, and 3.46 ± 0.91 at 5 years after bar removal. The rHI value increased significantly between all periods.

CONCLUSIONS

The Nuss procedure for young children may have the risk of recurrence during growth after bar removal.

LEVEL OF EVIDENCE

Level IV.

Thoracoscopic Costal Cartilage Excision Combined with the Nuss Procedure for Patients with Asymmetrical Pectus Excavatum

Background and Aims: We performed thoracoscopic costal cartilage excision (TCCE) combined with the Nuss procedure to correct asymmetrical pectus excavatum (PE). We reviewed the efficacy of combined TCCE and Nuss procedure for asymmetric PE. Patients and Methods: Overall, 8 patients with asymmetrical PE underwent TCCE with the Nuss procedure. The Haller index, asymmetry index, and angle of sternal rotation were calculated using preoperative computed tomography. The procedure was performed using bilateral 2.5-cm incisions at the same level of the deepest chest wall depression. The most depressed three to four costal cartilages were partially resected through a right mini-thoracotomy. Subsequently, one or two titanium bars were implanted and secured with stabilizers. The cosmetic outcome was evaluated on the following four ratings: excellent, good, fair, and failure ( = recurrence). Results: The median age at surgery was 14.5 years (8-20 years). The number of bars was one in 3 cases and two in 5 cases. The preoperative Haller index, asymmetry index, and angle of sternal rotation were 4.3 (3.5-5.9), 1.15 (1.04-1.26), and 21.5° (15°-31°), respectively; 2 patients had scoliosis before the Nuss procedure. Complications included surgical site infection and hemothorax. Median follow-up time was 25.5 months (3-63). Bars were removed in 3 patients, 3 years postoperatively. Cosmetic results were excellent, 4; good, 2; fair, 1; failure, 1. Both patients with scoliosis had poor outcomes (fair, 1; failure, 1). Conclusions: Combined TCCE with Nuss procedure is considered safe and effective for patients with asymmetrical PE. Careful long-term follow-up is required, especially in cases with scoliosis.

False-positive electrocardiographic changes during exercise test in a patient with pectus excavatum

Exercise-induced ST-segment changes simulating myocardial ischemia have been described in otherwise normal subjects during hyperventilation. We present the case of a 60-year-old man with pectus excavatum showing significant exercise-induced "pseudo-ischaemic" ST-segment changes with neither coronary artery disease nor anxiety-induced hyperventilation. We found no report of the possible causative role of a narrow antero-posterior chest diameter in inducing "pseudo-ischaemic" ST-segment changes during exercise stress test in the literature.

Outpatient monitoring of Pectus Excavatum: a Neural Network-based approach

Pectus Excavatum (PE) is a congenital anomaly of the ribcage, at the level of the sterno-costal plane, which consists of an inward angle of the sternum, in the direction of the spine. PE is the most common of all thoracic malformations, with an incidence of 1 in 300-400 people. To monitor the progress of the pathology, severity indices, or thoracic indices, have been used over the years. Among these indices, recent studies focus on the calculation of optical measures, calculated on the optical scan of the patient's chest, which can be very accurate without exposing the patient to invasive treatments such as CT scans. In this work, data from a sample of PE patients and corresponding doctors' severity assessments have been collected and used to create a decision tool to automatically assign a severity value to the patient. The idea is to provide the physician with an objective and easy to use measuring instrument that can be exploited in an outpatient clinic context. Among several classification tools, a Probabilistic Neural Network was chosen for this task for its simple structure and learning mode.

Prevalence of pectus excavatum in an adult population-based cohort estimated from radiographic indices of chest wall shape

BACKGROUND

Pectus excavatum is the most common chest wall skeletal deformity. Although commonly evaluated in adolescence, its prevalence in adults is unknown.

METHODS AND FINDINGS

Radiographic indices of chest wall shape were analyzed for participants of the first (n = 2687) and second (n = 1780) phases of the population-based Dallas Heart Study and compared to clinical cases of pectus (n = 297). Thoracic computed tomography imaging studies were examined to calculate the Haller index, a measure of thoracic axial shape, and the Correction index, which quantitates the posterior displacement of the sternum relative to the ribs. At the level of the superior xiphoid, 0.5%, 5% and 0.4% of adult Dallas Heart Study subjects have evidence of pectus excavatum using thresholds of Haller index >3.25, Correction index >10%, or both, respectively. Radiographic measures of pectus are more common in females than males and there is a greater prevalence of pectus in women than men. In the general population, the Haller and Correction indices are associated with height and weight, independent of age, gender, and ethnicity. Repeat imaging of a subset of subjects (n = 992) demonstrated decreases in the mean Haller and Correction indices over seven years, suggesting change to a more circular axial thorax, with less sternal depression, over time.

CONCLUSIONS

To our knowledge, this is the first study estimating the prevalence of pectus in an unselected adult population. Despite the higher reported prevalence of pectus cases in adolescent boys, this study demonstrates a higher prevalence of radiographic indices of pectus in adult females.

Prevalence of pectus excavatum (PE), pectus carinatum (PC), tracheal hypoplasia, thoracic spine deformities and lateral heart displacement in thoracic radiographs of screw-tailed brachycephalic dogs

Pectus excavatum, thoracic spine deformities, tracheal hypoplasia and lateral heart displacement are frequently described in brachycephalic dog breeds. Pectus carinatum is described sporadically, although the authors' observations demonstrate that it may occur in certain brachycephalic dog breeds. It was hypothesised that dogs of screw-tailed brachycephalic breeds carry a greater risk of these anomalies than normal-tailed brachycephalic breeds, and that there could a relation between the presence of pectus excavatum or pectus carinatum and thoracic spine deformities, tracheal hypoplasia and lateral heart displacement. During retrospective studies, these anomalies were identified in lateral and dorso-ventral radiographs of the thorax in brachycephalic dog breeds. A statistical analysis revealed that the frequency of pectus excavatum occurrence in screw-tailed and normal-tailed brachycephalic dog breeds is similar. The greatest risk of pectus excavatum occurrence is carried by two breeds: Maltese (60%) and English Bulldog (58%), while for pectus carinatum: Pug (41%) and French Bulldog (18%). Dogs of screw-tailed brachycephalic breeds carry a greater risk of kyphosis (p < 0.0001), tracheal hypoplasia occurrence (p < 0.0001), compared to "normal-tailed" breeds. The hypothesis concerning a relation between the presence of pectus excavatum or pectus carinatum and the other anomalies studied was not confirmed (p > 0.05). It was demonstrated that in dogs of brachycephalic breeds there was a greater risk of co-incidence between kyphosis of the thoracic spine and lateral heart displacement (p = 0.038), as well as kyphosis of the thoracic spine and tracheal hypoplasia (p = 0.003).

[Inferior vena cava compression in children with pectus excavatum]

INTRODUCTION

In severe cases of pectus excavatum (PE) the sternal depression may cause distortion of the cardiac chambers and great vessels. The aim of our study was to determine if the sternal impingement causes significant inferior vena cava (IVC) compression.

METHODS

Retrospective study of patients with severe PE assessed between 2015-2017. The antero-posterior (AP) and transverse diameters of the suprahepatic IVC were measured on a cardiac-MRI at the level of the diaphragmatic hiatus. Results were compared with patients that had a thoracic image study performed for other causes, adjusting for age and sex.

RESULTS

Among the 81 patients, 28 cases and 53 controls, 63% were males and had a mean age of 12.9±0.5 yrs. Significant differences were found between groups in both AP and transverse diameter of the IVC: 13.3±0.75 mm vs. 15.8±0.76 mm (p=0.001) and 28.8±1.34 mm vs. 27.1±0.89mm (p=0.045) respectively. After adjusting for age and sex, these differences were only statistically significant for AP IVC diameter in males 12.7±0.5 mm (95% CI 11.66-13.79 mm) vs. 16.6±0.5 mm (95% CI 15.69-17.56 mm) (p=0.000). The Pearson correlation coefficient for the Haller index was r=0.471 (p=0.01).

CONCLUSION

Male patients with severe sternal depression show changes in the IVC diameter that may correspond to compression. These changes are correlated with the severity of the deformity and can justify certain clinical symptoms and cardiac function abnormalities in patients with severe PE.

Characteristics of mitral valve leaflet length in patients with pectus excavatum: A single center cross-sectional study

The mitral valve morphology in patients with pectus excavatum (PE) has not been fully investigated. Thirty-five patients with PE, 46 normal controls, and patients with hypertrophic cardiomyopathy (HCM) who underwent 2 leaflet length measurements of Carpentier classification P2 and A2 using a transthoracic echocardiography were retrospectively investigated. The coaptation lengths and depths, papillary muscle tethering length, and mitral annular diameters were also measured. The P2 and A2 lengths were separately compared between 2 groups: older than 16 years and 16 years or younger. Furthermore, the correlations between actual P2 or A2 lengths and Haller computed tomography index, an index of chest deformity, were investigated in patients with PE exclusively. Among subjects older than 16 years, patients with PE had significantly shorter P2, longer A2, shorter copatation depth, and longer papillary muscle tethering length compared with normal controls. Similarly, patients with PE had significantly shorter P2 and shorter coaptation depth even compared with patients with HCM, while no significant difference was found in A2 length and papillary muscle tethering length. The same tendency was noted between 4 normal controls and 7 age- and sex-matched patients with PE ≤ 16 years old. No significant difference regarding A2/P2 ratio was found between patients with PE older and younger than 16 years. No significant correlation between the Haller computed tomography index and actual mitral leaflet lengths in patients with PE older than 16 years was noted; the same was observed for A2/P2 in all patients with PE. In conclusion, the characteristic features of the shorter posterior mitral leaflet, the longer anterior mitral leaflet, the shorter coaptation depth, and the longer papillary muscle tethering length in patients with PE was demonstrated. This finding might provide a clue regarding the etiology of mitral valve prolapse in PE at its possible earliest form.