Radiological assessment of children with pectus excavatum

Vacuum bell therapy for pectus excavatum: a retrospective study

BACKGROUND

Pectus excavatum, the most common chest wall deformity, is frequently treated with Nuss procedure. Here we will describe non-invasive procedure and analyze the variables associated vacuum bell therapy for patients with pectus excavatum.

METHODS

Retrospective case-control study in a single center between July 2018 and February 2022, including patients with pectus excavatum treated with vacuum bell. Follow-up was continued to September 2022. The Haller index and Correction index was calculated before and after treatment to analysis the effectiveness of vacuum bell therapy.

RESULTS

There were 98 patients enrolled in the treatment group, with 72 available for analysis, and the follow-up period ranged from 1.1 to 4.4 years (mean 3.3 years). When analyzing with the Haller Index, 18 patients (25.0%) showed excellent correction, 13 patients (18.1%) achieved good correction, and 4 patients (5.6%) had fair correction. The remaining patients had a poor outcome. Characteristics predicting a non-poor prognosis included initial age ≤ 11 years (OR = 3.94, p = 0.013) and patients with use over 24 consecutive months (OR = 3.95, p = 0.013). A total of 9 patients (12.5%) achieved a CI reduction below 10. Patients who started vacuum bell therapy at age > 11 had significantly less change compared to those who started at age ≤ 11 (P < 0.05). Complications included chest pain (5.6%), swollen skin (6.9%), chest tightness (1.4%) and erythema (15.3%).

CONCLUSIONS

A certain percentage of patients with pectus excavatum can achieve excellent correction when treated with pectus excavatum therapy. Variables predicting better outcome including initial age ≤ 11 years both in HI and CI and vacuum bell use over 24 consecutive months in HI. In summary, pectus excavatum is an emerging non-invasive therapy for pectus excavatum and will be widely performed in a certain group of patients.

Sternal Pin Used to Close Sternum in Infants after Cardiac Surgery

OBJECTIVE

A retrospective study was conducted to explore the efficacy of bioabsorbable poly-L-lactic acid sternal pins in sternal closure in infants after cardiac surgery.

METHODS

A total of 170 infantile patients who underwent cardiac surgery were divided into the steel wire group (group A), the PDS cord group (group B), and the steel wire + sternal pin group (group C). The occurrence of the thoracic deformity was evaluated by vertebral index (VI), frontosagittal index (FSI), and Haller index (HI) values; the stability of the sternum was evaluated by detecting sternal dehiscence and displacement.

RESULTS

By comparing the absolute values of the differences in VI, FSI, and HI in the three groups, it was found that the difference values of VI and HI in group C were significantly lower than those in group B (p = 0.028 and 0.005). For the highest deformation index, the deformation rate of infants in group C before discharge and during the 1-year follow-up was lower than that in group A and group B (p = 0.009 and 0.002, respectively). The incidence of sternal displacement in group C was also significantly lower than that in groups A and B (p = 0.009 and 0.009). During the 1-year follow-up, there was no sternal dehiscence, and the sternum healed completely in the three groups.

CONCLUSION

The use of "steel wire + sternal pin" for sternal closure in infants after cardiac surgery can reduce the occurrence of sternal deformity, reduce anterior and posterior displacement of the sternum, and improve sternal stability.

Association between intra-operative hemodynamic changes and corrective procedures during posterior spinal fusion in adolescent patients with scoliosis: A case-control study

Previous reports indicated that a decrease in intra-operative cardiac output and mean arterial pressure occurs due to thoracic cage deformities when patients with scoliosis are placed in the prone position. The aims of this study were to investigate the occurrence of hypotension during posterior spinal fusion in adolescent patients with scoliosis, and the association between hypotension, surgical procedures, changes of thoracic cage morphology.This retrospective, single-center, case-control study included 106 patients who underwent surgeries for spinal deformity at our institute between June 2014 and March 2020. The inclusion criteria were: age ≤19 years at the time of surgery, lowest instrumented vertebra over L5, posterior spinal fusion as the first surgery for scoliosis, and no severe cardiac or pulmonary disease pre-operatively. Finally, 49 patients met the criteria, and were divided to 3 groups as follows: thoracic constructive curve using a 6.0-mm cobalt-chromium alloy circular rod (T-C group; n = 28); thoracolumbar/lumbar constructive curve using a 6.0-mm cobalt-chromium alloy circular rod (L-C group; n = 8); and thoracic constructive curve using a 5.5-mm cobalt-chromium alloy beam-like rod (T-B group; n = 13). The beam-like rod is characteristic as the rod is mounted to screw heads without cantilever force. Intra-operative changes in circulation associated with corrective procedures, perioperative data, and sagittal depth and sternum deviation of thoracic cage were compared between the 3 groups.The T-C group had a higher rate of hypotension alarm than did the other groups (7 vs 0 vs 0; P = .047). Corrective procedures included rodding 4 times, rod rotation maneuver once, and direct vertebral rotation twice. Blood pressure was increased by pausing the correction procedures, increasing infusion, and administering vasopressors. The T-C and T-B groups had greater sternum deviation parameters than the L-C group, both before and after surgery. All parameters associated with sagittal depth and sternum deviation decreased significantly after surgery in the T-C and the T-B groups.In corrective surgery for constructive thoracic scoliosis, the corrective procedures requiring the application of compression force in the forward direction should be closely monitored in view of their possible influence on circulatory conditions.

The effect of minimally invasive pectus excavatum repair on thoracic scoliosis

OBJECTIVES

The Nuss technique comprises the placement of an intrathoracic bar behind the sternum. However, besides improving the body posture through the correction of the pectus excavatum (PE), this procedure may cause or worsen thoracic scoliosis as a result of the considerable stress loaded on the chest wall and the thorax. Our goal was to investigate the impact of the Nuss procedure on the thoracic spinal curvature in patients with PE.

METHODS

A total of 100 patients with PE who underwent the Nuss procedure were included in the study and evaluated retrospectively. The Haller index (HI), asymmetry index and sternal torsion angle were calculated from thoracic computed tomography images before the operation. To evaluate the scoliosis in the T2-T8 thoracic vertebrae, Cobb angles were calculated on a plain chest X-ray before the Nuss operation and after the removal of the bar. Cobb angles were classified as normal (5°), scoliotic posture (5°-10°) and scoliosis (>10°). All angles before and after the Nuss operation were compared. The patients were followed up for a mean of 41 months. Substernal bars were removed after a mean of 33 months.

RESULTS

The mean age of the patients was 19.6 ± 6.7 years. The Cobb angle was statistically significantly increased in all patients (P = 0.01), male patients (P = 0.01) and children (P = 0.046) but not in adults (P = 0.11) and female patients (P = 0.54). The Cobb angle was increased in patients with severe (HI ≥ 3.5) but not in patients with moderate (3.2 < HI < 3.5) or mild (2.0 < HI < 3.2) PE deformity.

CONCLUSIONS

The present study shows that the Cobb angle indicates that the severity of thoracic scoliosis increases following the Nuss procedure, particularly in male patients, in patients with mild and moderate sternal torsion angle and in those with a high preoperative HI. This alteration might be due to correctional forces and torque applied by the bar. Patients undergoing the Nuss procedure for the correction of PE should be followed up strictly for timely diagnosis and management of the scoliosis.

Computer-Aided Design and Manufacturing Technology for Identification of Optimal Nuss Procedure and Fabrication of Patient-Specific Nuss Bar for Minimally Invasive Surgery of Pectus Excavatum

The Nuss procedure is one of the most widely used operation techniques for pectus excavatum (PE) patients. It attains the normal shape of the chest wall by lifting the patient’s chest wall with the Nuss bar. However, the Nuss bar is for the most part bent by a hand bender according to the patient’s chest wall, and this procedure causes various problems such as the failure of the operation and a decreased satisfaction of the surgeon and patient about the operation. To solve this problem, we proposed a method for deriving the optimal operation result by designing patient-specific Nuss bars through computer-aided design (CAD) and computer-aided manufacturing (CAM), and by performing auto bending based on the design. In other words, a three-dimensional chest wall model was generated using the computed tomography (CT) image of a pectus excavatum patient, and an operation scenario was selected considering the Nuss bar insertion point and the post-operative chest wall shape. Then, a design drawing of the Nuss bar that could produce the optimal operation result was derived from the operation scenario. Furthermore, after a computerized numerical control (CNC) bending machine for the Nuss bar bending was constructed, the Nuss bar prototype was manufactured based on the derived design drawing of the Nuss bar. The Nuss bar designed and manufactured with the proposed method has been found to improve the Haller index (HI) of the pectus excavatum patient by approximately 37% (3.14 before to 1.98 after operation). Moreover, the machining error in the manufacturing was within ±5% compared to the design drawing. The method proposed and verified in this study is expected to reduce the failure rate of the Nuss procedure and significantly improve the satisfaction of the surgeon and patient about the operation.

Is pectus excavatum a risk factor for radiation-induced lung disease in patients undergoing radiation therapy following breast-conserving surgery?

Background

The relationship between radiation dose to the ipsilateral lung and subsequent radiation‐induced lung disease (RILD) in breast cancer patients with pectus excavatum (PE) undergoing radiation therapy (RT) to residual breast tissue after breast‐conserving surgery has not yet been established. The incidence of RILD in such patients with PE, meaning that a large volume of the lung is within the radiation field, has not been determined. Therefore, the aim of this study was to determine the relationship between these factors.

Methods

The study cohort comprised 133 women who underwent three‐dimensional conformal RT to residual breast tissue after breast‐conserving surgery for breast cancer. Diagnoses of PE were based on Haller's, frontosagittal, and Monden's depression indices. Radiation doses to the ipsilateral lung were established from dose‐volume histograms.

Results

Fifty of the 133 participants (37.6%) were diagnosed with RILD; all were asymptomatic. Multivariate analysis revealed a significant correlation between the incidence of RILD and the administration of > 30 Gy (V30). Surprisingly, although patients with PE received higher ipsilateral lung doses, they were less likely to develop RILD than those without PE.

Conclusions

Our data indicate that the incidence of RILD is correlated with the administration of > 30 Gy (V30) and that PE is not a risk factor for RILD after RT to residual breast tissue after breast‐conserving surgery for breast cancer. Surprisingly, individuals with PE may have a lower incidence of RILD than those without this condition.

Quantification of pectus excavatum: Anatomic indices

Pectus excavatum is the most common chest wall deformity in children. The central portion of the chest is displaced posteriorly relative to the remainder of the anterior chest wall. Quantification of defect severity can be performed with multiple imaging modalities or external thoracic measures, but is most commonly quantified by the Haller Index (HI) or Pectus Correction Index (PCI). These two measures provide a measure of the chest based on cross sectional imaging, most commonly CT scans, allowing for standard comparison and definitions of pectus defects. The purpose of this article is to describe the creation, calculation, and limitations of the methods quantifying pectus defects.

A new methodology for assessment of pectus excavatum correction after bar removal in Nuss procedure: Preliminary study

PURPOSE

The objective is to present a new methodology to assess quantitatively the impact of bar removal on the anterior chest wall, among patients with pectus excavatum who have undergone the Nuss procedure, and present a preliminary study using this methodology.

METHODS

We propose to acquire, for each patient, the surface of the anterior chest wall using a three-dimensional laser scanner at subsequent time points (short term: before and after surgery; long term: follow-up visit, 6months, and 12months after surgery). After surfaces postprocessing, the changes are assessed by overlapping and measuring the distances between surfaces. In this preliminary study, three time points were acquired and two assessments were performed: before vs after bar removal (early) and before vs 2-8weeks after bar removal (interim). In 21 patients, the signed distances and volumes between surfaces were computed and the data analysis was performed.

RESULTS

This methodology revealed useful for monitoring changes in the anterior chest wall. On average, the mean, maximum, and volume variations, in the early assessment, were -0.1±0.1cm, -0.6±0.2cm, and 47.8±22.2cm³, respectively; and, in the interim assessment, were -0.5±0.2cm, -1.3±0.4cm, and 122.1±47.3cm³, respectively (p<0.05). Data analysis revealed that the time the bar was in situ was inversely and significantly correlated with postretraction and was a relevant predictor of its decrease following surgery (p<0.05). Additionally, gender and age suggested influencing the outcome.

CONCLUSIONS

This methodology is novel, objective and safe, helping on follow-up of pectus excavatum patients. Moreover, the preliminary study suggests that the time the bar was in situ may be the main determinant of the anterior chest wall retraction following bar removal. Further studies should continue to corroborate and reinforce the preliminary findings, by increasing the sample size and performing long-term assessments.

LEVELS OF EVIDENCE

III.

Pectus excavatum: computed tomography and medium-term surgical outcome in a prospective cohort of 10 kittens

OBJECTIVES

The objective of this study was to report the use of computed tomography (CT) in conjunction with clinical signs to assess the severity of pectus excavatum (PE) in kittens and to guide surgical decision-making; also to report medium-term outcome in a prospective cohort of kittens undergoing surgical correction.

METHODS

This was a prospective study of 10-15-week-old kittens (n = 10) diagnosed with moderate/severe PE.

RESULTS

CT provides additional information that is useful for selecting patients for surgical correction and for planning the surgery. Traditional radiographic indices (vertebral, frontosagittal) provide reasonable approximations of the CT-determined dimensions but these seem to correlate poorly with the severity of clinical signs. Kittens commonly have lateralised deformities, which are associated with less severe clinical signs, while those with midline deformities are associated with more severe clinical signs. Six of seven kittens with severe PE that had a ventral splint applied for 4 weeks had excellent medium-term outcomes.

CONCLUSIONS AND RELEVANCE

Restriction of diastolic filling by midline sternal deviation may be an important cause of exercise intolerance in cats with PE. CT can be used to assess affected kittens and to plan surgery when indicated.

Radiologic factors related to double-bar insertion in minimal invasive repair of pectus excavatum

BACKGROUND

Pectus excavatum is the most common congenital chest wall deformity, with a high incidence in live births. This study aimed to evaluate the measured factors on CT images related to the number of pectus bars for surgical correction.

METHODS

A total of 497 patients who had undergone minimally invasive repair between April 2007 and July 2011 were classified into single-bar (n=358) and double-bar (n=139) insertion groups. We measured eight distinct distances and one angle on CT scans to reflect quantitative assessment. Univariate analysis and multivariate logistic regression analysis were performed to detect statistically significant association between radiologic measurements and the pectus bars required.

RESULTS

After adjusting for age and gender, the transverse distance (T), the transverse distance of the depression area (A), the inclined distance of the depression area (B), the AP distance of the depression area (C), the depression angle (G), and the eccentric distance of deformity (E) were significantly correlated with double-bar insertion. The regression model showed that age (P<0.0001), gender (P<0.0001), depression angle (G) (P<0.0001), direction of the depression (DD) (P<0.0001) and depression depth (D) (P<0.0001) were significantly associated with double-bar insertion.

CONCLUSION

CT scan provides useful factors which can be of assistance in predicting the number of pectus bars for the surgical correction of pectus excavatum.

Chest fast MRI: an imaging alternative on pre-operative evaluation of Pectus Excavatum

BACKGROUND

Standard imaging methods in evaluating chest wall deformities, such as Pectus Excavatum (PE) in paediatric and adolescent patients, include baseline 2-view chest radiography and chest CT scan. Only few studies to date investigated the value of fast MRIin the pre operative assessment of patient affected by PE.

OBJECTIVE

To evaluate the efficacy of chest fast MRI in pre-operative management of patient affected by PE. To obtain the Haller Index (HI) and Asymmetry Index (AI) from chest fast MRI protecting patients from radiation exposure.

MATERIALS AND METHODS

We analyzed the data of 42 consecutive patients with severe PE who underwent minimally invasive repair between March 2007 and March 2010. All 42 patients received chest fast MRI, but only the first 5 in view of the results, were studied also with chest ultrafast CT scan. In both examinations, data at the deepest point of the depression were collected.

RESULTS

Severity indices of the deformity using HI and AI, collected from CT scan and fast MRI in the first 5 patients, were comparable. In the remaining 37 fast chest MRI offered good images of the chest wall deformities with no radiation exposure, detailing anatomical information such as displacement and rotation of the heart or great vessels anomalies.

CONCLUSION

This study suggests the use of chest MRI in pre operative workup for patients with PE to obtain severity indices (Haller Index and Asymmetry Index avoiding radiation exposure to paediatric patients.

Indications and technique of Nuss procedure for pectus excavatum

Pectus excavatum most frequently involves the lower sternum and chest wall. Because the morphology varies, preoperative imaging for anatomic assessment and documentation of dimensions of the chest are important. Many modifications have been made to the minimally invasive procedure since it was first performed in 1987. As a result, there has been an increase in the number of patients seeking surgical correction. This article discusses the clinical features of pectus excavatum and reviews the preoperative considerations and the steps involved in the repair of the deformity.

Pectus excavatum: historical background, clinical picture, preoperative evaluation and criteria for operation

Pectus excavatum is a depression of the sternum and costal cartilages which may present at birth, or more commonly during the teenage growth spurt. Symptoms of lack of endurance, shortness of breath with exercise, or chest pain are frequent. Although pectus excavatum may be a component of some uncommon syndromes, patients usually are healthy. Evaluation should include careful anatomic description with photographs, radiography to demonstrate the depth of the depression, extent of cardiac compression, or displacement, measurement of pulmonary function, and echocardiography to look for mitral valve prolapse (in 15%) or diminished right ventricular volume. Indications for surgical treatment include two or more of the following: a severe, symptomatic deformity; progression of deformity; paradoxical respiratory chest wall motion; computer tomography scan with a pectus index greater than 3.25; cardiac compression/displacement and/or pulmonary compression; pulmonary function studies showing restrictive disease; mitral valve prolapse, bundle branch block, or other cardiac pathology secondary to compression of the heart; or failed previous repair(s). The developmental factors, genetics, and physiologic abnormalities associated with the condition are reviewed.