Evaluation of the Nuss procedure using pre- and postoperative computed tomographic index

Surface topography index: a novel deformity severity assessment index for pectus excavatum

BACKGROUND

The surface topography index (STI) has great potential in both routine computed tomography (CT) scan and emerging optical imaging systems. However, the diagnostic accuracy and stability of the STI as a deformity severity assessment index has not been fully confirmed. Therefore, the aim of the present study was to determine the diagnostic performance of the STI as a novel deformity severity assessment index for pectus excavatum.

METHODS

The present study consisted of 722 chest CT images from a single center. The standard CT index (CTI) and STI were calculated for all patients. The between-group difference and the level of compliance between the CTI and STI was analyzed by t-test and Pearson correlation. The diagnostic value and optimum discriminatory values of the CTI and STI were calculated by a receiver-operating characteristic (ROC) curve and DeLong's test.

RESULTS

The distributions of the CTI and STI were similar and showed a slight overlap between the pectus excavatum (PE) and non-PE groups. Both the CTI and STI significantly differed between the 2 groups (P<0.001). The STI demonstrated a strong Pearson correlation with the CTI (r=0.91, 95% confidence interval: 0.88-0.91, P<0.001). The ROC curves showed that STI =1.58 (sensitivity: 0.93, specificity: 0.95) could be considered equivalent to CTI =2.72 (sensitivity: 0.93, specificity: 0.97) as the optimum discriminatory values. DeLong's test showed no significant difference in the ROC curve results between the CTI and STI (Z=0.90, P=0.37).

CONCLUSIONS

The STI has comparative discrimination ability in PE diagnosis and deformity severity assessment when used with the standard CTI. The STI as a novel index is not only an ideal evaluation metric of PE deformity but also an objective trait for PE patients just as weight and height for everyone.

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.

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.

Thoracic Magnetic Resonance Imaging Applications in Children

Lung pathologies in the pediatric population can usually be detected using chest radiography. Multidetector computed tomography (MDCT) imaging is often used as a supplementary method in the evaluation of lung diseases. Recently, magnetic resonance imaging (MRI) techniques were found to be reliable in the evaluation of pulmonary diseases in the pediatric population. This review study describes the routine application of MRI examinations and the use of thoracic MRI with a particular focus in pediatric patients.

Surgical Correction of Pectus Excavatum by the Nuss Procedure: A 15-Year Experience Study

Pectus excavatum is the most common congenital deformity of the chest. The Nuss procedure is minimally invasive surgical correction of this defect, using retrosternal metal bars. The purpose of the present study was to describe a 15-year experience with the Nuss surgery, and to evaluate the long-term clinical results of the procedure. We retrospectively evaluated 239 patients, aged 14-34, who underwent the Nuss surgery in the years 2002-2016. Postoperative complications were observed in 40/236 (16.9%) patients. The most common complication was pneumothorax in 14/239 patients. Less common were the following: wound infection in 4, pleural effusion in 3, allergy to nickel in 1, lung atelectasis in 1, and ventricular failure in 1 patient. Three patients were treated because of severe postoperative pain, and in one case the implant had to be removed. Postoperative complications associated with the number of bars inserted, but not with the patient age or gender. A satisfactory and long lasting corrective effect of surgery was observed in 231/239 (96.7%) of patients. There was no perioperative mortality. We conclude that the Nuss surgery is a safe surgery that demonstrates excellent and long-lasting esthetic results, with a low risk of severe complications.

Effect of the Nuss Procedure on the Physical Development of Patients with Pectus Excavatum

PURPOSE

This study assessed physical development of patients with pectus excavatum and evaluated the effect of the Nuss procedure on physical development.

METHODS

A total of 146 patients underwent the Nuss procedure; of these, at the time of the study, the bar had been removed from 123 patients (84.9%; male 93, female 30) who were eligible for participation in this study. Heights and body weights of patients were measured prior to surgery and immediately before bar removal. Chest computed tomography (CT) was performed preoperatively and immediately before bar removal. The associations between physical development and chest CT indices were evaluated.

RESULTS

The height standard deviation score (SDS) was - 0.66 ± 2.23 preoperatively and 0.04 ± 1.34 immediately before bar removal (p <0.01). The weight SDS was - 0.02 ± 2.59 preoperatively; it increased significantly to 0.56 ± 1.56 immediately before bar removal (p <0.01). The Haller index (3.85 ± 1.18 to 2.99 ± 0.54; p <0.01) and asymmetric index (9.75 ± 6.63 to 7.01 ± 4.77; p <0.01) also showed improvements.

CONCLUSIONS

The Nuss procedure may contribute positively to the physical development of patients with pectus excavatum.

Multicenter study of pectus excavatum, final report: complications, static/exercise pulmonary function, and anatomic outcomes

BACKGROUND

A multicenter study of pectus excavatum was described previously. This report presents our final results.

STUDY DESIGN

Patients treated surgically at 11 centers were followed prospectively. Each underwent a preoperative evaluation with CT scan, pulmonary function tests, and body image survey. Data were collected about associated conditions, complications, and perioperative pain. One year after treatment, patients underwent repeat chest CT scan, pulmonary function tests, and body image survey. A subset of 50 underwent exercise pulmonary function testing.

RESULTS

Of 327 patients, 284 underwent Nuss procedure and 43 underwent open procedure without mortality. Of 182 patients with complete follow-up (56%), 18% had late complications, similarly distributed, including substernal bar displacement in 7% and wound infection in 2%. Mean initial CT scan index of 4.4 improved to 3.0 post operation (severe >3.2, normal = 2.5). Computed tomography index improved at the deepest point (xiphoid) and also upper and middle sternum. Pulmonary function tests improved (forced vital capacity from 88% to 93%, forced expiratory volume in 1 second from 87% to 90%, and total lung capacity from 94% to 100% of predicted (p < 0.001 for each). VO2 max during peak exercise increased by 10.1% (p = 0.015) and O2 pulse by 19% (p = 0.007) in 20 subjects who completed both pre- and postoperative exercise tests.

CONCLUSIONS

There is significant improvement in lung function at rest and in VO2 max and O2 pulse after surgical correction of pectus excavatum, with CT index >3.2. Operative correction significantly reduces CT index and markedly improves the shape of the entire chest, and can be performed safely in a variety of centers.

Correlation of asymmetric chest wall deformity and growth in patients with pectus excavatum

PURPOSE

Pectus excavatum involves wide range of chest wall depression. The degree of depression or asymmetry varies between young and adolescent patients. It has not been clear how the deformity progresses as patients grow. To elucidate the change of asymmetric deformity, preoperative computed tomography (CT) scan was evaluated according to different age groups.

METHODS

Preoperative CT scans of 154 patients with pectus excavatum were collected and analyzed using Haller's CT index, asymmetric index and sternal rotation angle. Patients were divided into 5 age groups as follows; group 1: 4-6 y (n=53), group 2: 7-9 y (n=25), group 3: 10-12 y (n=25), group 4: 13-15 y (n=23), group 5: 16-23 y (n=28). The degree of asymmetric chest wall deformity was expressed using sternal rotation angle as follows; symmetrical (-5º to +5º), left-mild (-5º to -15º), right-mild (+5º to +15º), right-moderate (+15º to +25º) and right-severe (over +25º).

RESULTS

As the age of patients increased, asymmetric index increased from 1.025±0.065 in group 1 to 1.124±0.111 in group 5 and sternal rotation angle also increased from 6.11±8.61 in group 1 to 15.41±11.98 in group 5. In these two parameters, significant difference was seen between group 1 and 4, group 2 and 4, group 1 and 5 and group 2 and 5. However, average CT index revealed no significant difference in any age groups. In group 1, 83% of patients were classified in symmetrical or left- and right-mild. The incidence of right-moderate plus right-severe was 17% in group 1, 20% in group 2, 40% in group 3, 52.1% in group 4 and 50% in group 5.

CONCLUSIONS

The degree of chest depression did not show any change in all age groups. Asymmetric deformity on the right side progressed around the age of 10 to 12. Half of patients over the age of 13 showed moderate or severe asymmetry. These results were suggestive to consider the optimum age for the correction of pectus excavatum.

Usefulness of chest images for the assessment of pectus excavatum before and after a Nuss repair in adults

OBJECTIVES

The aim of this study was to evaluate whether chest radiographs could offer useful information for the assessment of pectus excavatum (PE) before and after Nuss repair in adults.

METHODS

A total of 154 adults, with a mean age of 24.0 ± 5.0 years (range, 18-44 years), who underwent a Nuss repair of PE, with a mean follow-up of 42 months (range, 14-71 months), were included in this retrospective study. Sixty-two of these patients were also evaluated after the pectus bar removal, with a mean follow-up of 13 months (range, 6-44 months). The preoperative and postoperative imaging modalities were compared.

RESULTS

The preoperative mean Haller indices measured on computed tomography (CT) and chest radiographs were 4.61 ± 1.58 (range, 2.6-11.9) and 3.82 ± 1.17 (range, 2.0-10.2), respectively. The Pearson correlation coefficient between the two parameters was 0.757. The postoperative mean Haller index measured on chest radiographs was 2.86 ± 0.56 (range, 1.7-5.4) and showed statistically significant improvement compared with the preoperative index (P < 0.001). The mean sternovertebral (SV) distances detected on preoperative and postoperative (>6 months after surgery) lateral chest radiographs were 7.67 ± 1.89 cm (range, 2.5-12.9 cm) and 9.89 ± 1.80 cm (range, 4.6-15.0 cm), respectively, showing statistically significant improvement (P < 0.001). The mean sternovertebral (SV) distance in patients after the bar removal detected on lateral chest radiographs was 9.25 ± 2.14 cm, also showing statistically significant improvement compared with the preoperative value (P < 0.001).

CONCLUSIONS

Haller indices measured using chest radiographs and CT showed a strong correlation. Therefore, chest radiographs can be used as an alternative tool for the preoperative evaluation of PE. The Nuss operation significantly improved SV distances detected on lateral chest radiographs. Lateral chest radiographs can be used as a simple modality for the objective quantitative assessment of the anatomic results and follow-up of the Nuss operation in adults.

Three-dimensional computed tomography for evaluation and management of children with complex chest wall anomalies: useful information or just pretty pictures?

PURPOSE

Shaded surface display (SSD) technology, with 3-dimensional computed tomography reconstruction, has been reported in a few small series of patients with congenital or acquired chest wall deformities. Shaded surface display images are visually attractive and educational, but many institutions are hesitant to use these secondary to cost and image data storage concerns. This study was designed to assess the true value of SSD to the patient, family, and operating surgeon, in the evaluation and management of these children.

METHODS

After institutional review board approval, we performed a retrospective review of records of 82 patients with chest wall deformities, evaluated with SSD, from 2002 to 2009. Shaded surface display usefulness, when compared to routine 2-dimensional computed tomography, was graded on a strict numerical scale from 0 (added no value besides education for the patient/family) to 3 (critical for surgical planning and patient management).

RESULTS

There were 56 males and 26 females. Median age was 15.3 years (range, 0.6-41.1 years). Deformities included 56 pectus excavatum, 19 pectus carinatum, and 8 other/mixed deformities. Six patients also had acquired asphyxiating thoracic dystrophy (AATD). Eleven (13%) had previous chest wall reconstructive surgery. In 25 (30%) patients, SSD was useful or critical. Findings underappreciated on 2-dimensional images included sternal abnormalities (29), rib abnormalities (28), and heterotopic calcifications (7). Shaded surface display changed or influenced operation choice (4), clarified bone vs soft tissue (3), helped clarify AATD (3), and aided in rib graft evaluation (2). Point biserial correlation coefficient analysis (R(pb)) displayed significance for SSD usefulness in patients with previous chest repair surgery (R(pb) = 0.48, P ≤ .001), AATD (R(pb) = 0.34, P = .001), pectus carinatum (R(pb) = 0.27, P = .008), and females (R(pb) = 0.19, P = .044).

CONCLUSIONS

Shaded surface display, when used to evaluate children and young adults with congenital or acquired chest wall deformities, provides useful or critical information for surgical planning and patient management in almost one third of patients, especially in those requiring a second operation, with acquired asphyxiating thoracic dystrophy, pectus carinatum, and females.

Incomplete left bundle branch block as an artefact caused by the Nuss procedure for pectus excavatum

AIMS

Nuss procedure is an established and well approved minimally invasive technique for the correction of pectus excavatum. Hereby an individually curved steel bar is inserted to stabilize the thorax. This study aimed to describe ECG changes associated with this procedure.

METHODS AND RESULTS

Electrocardiographs of 65 patients who underwent Nuss procedure in our Hospital were evaluated before and after bar implantation as well as after bar removal. In the Goldberger leads, there was a consistent reduction in the QRS amplitude in lead I. In the Wilson leads, the most prominent change was a reduction in the QRS amplitude and a novel r' wave forming a slightly elevated J-point in the left lateral leads. Additionally, we noticed the loss of the former small and physiological q wave in the same leads, typical for an incomplete left bundle branch block (ILBBB). These changes resolved after bar removal.

CONCLUSION

We describe the common finding of a reversible incomplete ILBBB after Nuss surgery. The reason for these ECG changes remain unclear. Since cardiac ischaemia, damage, or perioperative irritation of the pericardium is improbable and the alteration of the anatomic thoracic situation remains after bar explantation, we suspect an artefact through alteration of the electric field by the steel bar. Practitioners dealing with patients after Nuss procedure should be aware of this most probably harmless finding.

Surgical correction of the funnel chest deformity in children

The aim of this study was to evaluate our results during and after the Nuss operation in children with pectus excavatum. We have performed the Nuss procedure in 128 patients with pectus excavatum since 2001, and 74 patients underwent bar removal. Of the 128 patients 96 were male and 32 were female; age ranged from eight to 21 years with an average of 13.8 years. In 46% of patients psychological reasons for operative treatment were dominant while in the other 54% of patients clinical signs were the indications. Complications in 128 patients included 36 pneumothorax, 28 of which resolved spontaneously. Postoperative pneumonia developed in six patients. In two patients we had infection of the implanted bar, and there were two patients with cellulitis. We had six patients with bar displacement and reoperation was needed. During the Nuss procedure we had one injury of the intercostal artery. We had pericardial tears in two patients without clinical significance. In two patients we had pericardial effusion six months after the Nuss procedure, requiring pericardiocentesis. In one patient we had fracture of the sternum. There were no complications following bar removal. After bar removal in 74 patients, 54 patients (72.9%) maintained excellent results with normal chest anatomy, good results were found in 16 patients (21.6%) with mild residual pectus and poor results in four patients (5.5%) with severe recurrence. Our experience with the Nuss procedure demonstrated excellent results with few minor complications.

Minimally invasive repair of pectus excavatum deformity

This review is trying to address the effectiveness and sustainability of results following minimally invasive repair of pectus excavatum (MIRPE). The aim is to present these results for the benefit of clinicians and the patients. Literature search has revealed 179 hits, which were independently assessed and led to 80 publications being formally reviewed. Studies reporting results from less than 10 patients were excluded. Thirty-five studies were found to be reporting results from patients' and/or surgeons' perspective and they were included in this review. Data from the United Kingdom registry for MIRPE were also included. Results from over 2997 patients (age: <1-85 years) who had MIRPE and 1393 patients who had their metallic bar removed were assessed. The most common indication for surgery was cosmesis. There was a net gain with regard to self-esteem for 96-100% of the individuals. A percentage of procedures (0-20%) was assessed by surgeons as having an 'unsatisfactory outcome' and a number of patients (0-25%) reported an 'unsatisfactory end result.' However, these percentages are not necessarily referring to the same patients and an unsatisfactory result does not seem to affect the positive effect on self-esteem. The reported changes in social life, lung capacity, cardiovascular capacity, exercise capacity and general health are based on weak data and significant improvements, if any, are probably seen in a limited number of patients. The metallic bars were removed after 1.5-4.5 years and there is an overall 0-4.5% reported recurrence post-bar removal. In conclusion, MIRPE may improve cosmesis and self-esteem of patients with pectus excavatum deformity. Direct or indirect improvement in other physiological parameters may also help the 'well-being' of these patients and their social integration. There is a clear need for standardisation in the way results are reported in the literature and a socioeconomic analysis with regard to gains, benefits and costs related to MIRPE.

Analysis of changes to the anterior chest wall after the Nuss procedure-an objective measurement of pectus excavatum

INTRODUCTION

We report a noninvasive method for recording the deviation of the anterior chest wall (ACW) in patients with pectus excavatum before and after the insertion and removal of a Nuss bar.

PATIENTS AND METHOD

All patients undergoing the Nuss procedure at our institutions between June 2008 and February 2009 were enrolled in this study. A thermal plastic strip was used to cast the ACW at the skin level along the area corresponding to the tract of the inserted bar. The height of the ACW was defined as the perpendicular length from the xiphoid process to the transverse line drawn between the 2 midaxillary points.

RESULTS

Bar insertion caused a significant increase in ACW height and width. Bar removal reduced the corrective effects in terms of a significant decrease in ACW height; at the same time, an increase in ACW width was noted.

CONCLUSION

Feature extraction and analyses of permanent contour casts of the ACW help to understand immediate changes in the ACW after the Nuss procedure and may assist in the design of the bar at insertion. The Nuss bar in situ helped to maintain cosmetic benefits to the ACW.

Development of new cardiac deformity indexes for pectus excavatum on computed tomography: feasibility for pre- and post-operative evaluation

PURPOSE

The aim of this study was to evaluate new cardiac deformity indexes (CDIs) for diagnosis of pectus excavatum as well as morphological assessment of heart on computed tomography (CT).

MATERIALS AND METHODS

We retrospectively evaluated the CT images of the control group (n=200), and the pectus excavatum before and after correction groups (n=178), and calculated the CDIs; cardiac compression index (CCI), and cardiac asymmetry index (CAI). We also calculated chest wall compression index (CWCI) and asymmetry index (CWAI) on the axial images. We performed logistic regression analysis using each index and age as predictor variables.

RESULTS

The CDIs (CCI and CAI) were significant (p < 0.05) in the diagnosis of pectus excavatum, regardless of age (p = 0.4033, p = 0.8113). The CWCI and CWAI were significant (p < 0.05) and significantly affected by age (p < 0.05). If we selected 1.82 as the cutoff of the CCI, the sensitivity and specificity were 99.4% and 98%, respectively. The following cutoffs and the sensitivity and specificity were obtained: 1.15 for the CAI gave 94.4% and 94.5%, 3.05 for the CWCI gave 92.1% and 92%, and 1 for the CWAI gave 62.4% and 65%, respectively. The CCI after repair improved from 2.83 +/- 0.84 to 1.84 +/- 0.33, while the CWCI improved from 4.49 +/- 1.61 to 2.57 +/- 0.44.

CONCLUSION

CDIs such as the CCI and CAI may be potentially useful to detect and estimate repair for pectus excavatum.