Structural and functional development in airways throughout childhood: Children are not small adults.

Children are not small adults and this fact is particularly true when we consider the respiratory tract. The anatomic peculiarities of the upper airway make infants preferential nasal breathers between 2 and 6 months of life. The pediatric larynx has a more complex shape than previously believed, with the narrowest point located anatomically at the subglottic level and functionally at the cricoid cartilage. Alveolarization of the distal airways starts conventionally at 36-37 weeks of gestation, but occurs mainly after birth, continuing until adolescence. The pediatric chest wall has unique features that are particularly pronounced in infants. Neonates, infants, and toddlers have a higher metabolic rate, and consequently, their oxygen consumption at rest is more than double that of adults. The main anatomical and functional differences between pediatric and adult airways contribute to the understanding of various respiratory symptoms and disease conditions in childhood. Knowing the peculiarities of pediatric airways is helpful in the prevention, management, and treatment of acute and chronic diseases of the respiratory tract. Developmental modifications in the structure of the respiratory tract, in addition to immunological and neurological maturation, should be taken into consideration during childhood.

Normative Data of Pulmonary Function Tests and Radiographic Measures of Chest Development in Children Without Spinal Deformity: Is a T1-T12 Height of 22 cm Adequate?

STUDY DESIGN: Retrospective case series. OBJECTIVES: To develop normative data of pulmonary function tests (PFTs) and radiographic measures of chest development in normal children and to determine if the prior proposed T1-T12 height of 22 cm for spinal fusion in a growing child is adequate for pulmonary function based on normative PFT values at skeletal maturity. SUMMARY OF BACKGROUND DATA: Shortening of the spine from T1-T12 is a concern with early thoracic fusion for spinal deformity, as it has a deleterious effect on the development of the pulmonary system. METHODS: Children with mild asthma who had pulmonary function tests (PFTs) >90% and without chest or spinal deformity were identified. PFT data included absolute forced vital capacity (FVC), %-predicted FVC, absolute forced expiratory volume in one second (FEV1), %-predicted FEV1, and FEV1/FVC. Radiographic measurements performed on chest radiographs included T1-T12 height, coronal chest width (CCW), and space available for the lung (SAL) bilaterally. These data were analyzed for all patients and for patients with T1-T12 heights 22-24 cm. To assess the impact of T1-T12 shortening on PFTs at skeletal maturity, spirometric standards for healthy adult lifetime nonsmokers were used. RESULTS: Of 1,797 PFT studies, 149 children (average age 12.4 ± 3.0 years; girls, 97) were analyzed. For the entire cohort, PFT values were as follows: FVC 3.0 ± 0.9 L, %-predicted FVC 103.9% ± 10.6%, absolute FEV1 2.7 ± 0.9 L, %-predicted FEV1 106.9% ± 11.1%, and FEV1/FVC 90.7% ± 2.6%. The averages for T1-T12 height was 25.6 ± 3.8 cm, CCW 25.5 ± 3.4 cm, and SAL bilaterally 19.0 ± 3.5 cm. For the 21 patients (girls 11; average age 9.7 ± 1.4 years) with T1-T12 heights 22-24 cm, absolute FVC was 2.2 ± 0.3 L, %-predicted FVC was 104.0% ± 13.0%, absolute FEV1 was 2.0 ± 0.3 L, %-predicted FEV1 was 108.2% ± 15.0%, and FEV1/FVC was 91.0% ± 2.7%. If these kids with 22-24 cm T1-T12 heights maintained the same thoracic height, they were calculated to have %-predicted FVC of 44% (girl) and 42% (boy) and %-predicted FEV1 of 42% (girl) and 43% (boy) at skeletal maturity (15 years old). CONCLUSIONS: Percent-predicted FEV1 and FVC values for normal children with a T1-T12 height of 22 cm at skeletal maturity were <50%. Though this analysis does not take into consideration radial expansion of the chest or children with scoliosis (idiopathic, congenital, neuromuscular), these values are concerning and may not be adequate to guarantee that children with early-onset scoliosis who are fused with T1-T12 heights of 22 cm will have an asymptomatic pulmonary status in adulthood. LEVEL OF EVIDENCE: Level IV.

Chest Wall Constriction after the Nuss Procedure Identified from Chest Radiograph and Multislice Computed Tomography Shortly after Removal of the Bar.

BACKGROUND: This study radiographically examined the changes in the chest walls of patients with pectus excavatum (PE) after Nuss bar removal, to define the deformation caused by the bar and stabilizer. In the first part of the study, we compared the changes in chest radiographs of patients with PE to a preoperation PE control group. In the second part, we used multislice computed tomography (CT) scans to provide three-dimensional reconstructions with which to evaluate the changes to the thoracic wall. METHODS: Part 1 From June 2006 to August 2011, 1,125 patients with PE who had posteroanterior chest radiographs taken before undergoing the Nuss procedure at four hospitals were enrolled as a preoperative control group. At the same time, 203 patients who had the bar removed were enrolled as the study group. The maximum dimensions of the outer boundary of the first to ninth rib pairs (R1-R9, rib pair width), chest height, and chest width were measured. Part 2 Thirty-one consecutive patients with PE (20 males and 11 females) who underwent Nuss bar removal were evaluated 7 to 30 days after operation. During this period, a further 34 patients with PE who had undergone CT imaging before bar insertion were evaluated and compared with the postoperative group. RESULTS: Part 1 The width of the lower ribs (R4-R9) after bar removal was significantly less than in the age-matched controls. The ribs adjacent to the bar (R5-R7) showed the greatest restriction. The width of the upper ribs (R1-R3) 2 to 3 years after bar placement did not differ significantly from the controls. Patients who were operated on after 10 years of age had less of a restrictive effect. Three years of bar placement resulted in more restriction than a 2-year period, particularly in patients younger than 10 years old. Part 2: A significant constriction of the chest wall was observed in 13 patients after removal of the Nuss bar. Constriction at ribs 5 to 8 was found to be present adjacent to the site of bar insertion. However, constriction of the chest wall was found in only 3 of the 34 patients in the preoperative group. The severity of constriction (as graded by the spline model) also increased in the postoperative group. CONCLUSION: The growth of the chest wall was restricted after placement of the Nuss bar for PE correction. Long-term follow-up of chest wall growth is needed to clarify whether such constriction resolves with time.

Is the vertebral expandable prosthetic titanium rib a surgical alternative in patients with spina bifida?

BACKGROUND: Nonambulatory children with myelodysplasia are most likely to develop spinal deformity. As the deformity progresses, the overall health of the patient deteriorates. Traditional management of the deformity with fusion results in a short trunk, crankshaft deformity, and spine and lung growth inhibition. One alternative that potentially minimizes these problems is the vertebral expandable prosthetic titanium rib (VEPTR). QUESTIONS/PURPOSES: We therefore asked whether the use of the VEPTR in immature nonambulating children with myelodysplasia with spinal deformity would (1) correct deformity; (2) allow growth; and (3) allow adequate respiratory function. PATIENTS AND METHODS: We identified 20 nonambulatory patients with myelodysplasia who were part of a multicenter Investigational Device Exemption study of 214 patients treated with the VEPTR system. Demographics, standard radiographic measurements, pulmonary function parameters, and complications in 16 patients were analyzed. Average age at first surgery was 48.6 months. The minimum followup was 25 months (mean, 59 months; range, 25-164 months). RESULTS: The Cobb angle decreased postoperatively in nine patients, increased less than 10° in five patients, and increased less than 20° in two patients. The mean increase in thoracic spinal length (growth) by year after the initial procedure with lengthening was 0.48 cm. Ventilatory function improved in 11 patients and deteriorated in five patients. Intraoperative complications occurred in two patients. Complications directly related to the implant were seven infections and five implant migrations. CONCLUSIONS: Our observations suggest VEPTR is a reasonable treatment option for spinal deformity in the immature, nonambulatory myelodysplasia population correcting the spinal deformity, allowing spinal growth, and maintaining adequate respiratory function. The rate of complications is within the range reported for spinal fusion using standard approaches.

Restrictive chest wall deformity as a complication of surgical repair for pectus excavatum.

The Ravitch operation is frequently performed to correct pectus excavatum. However, extensive destruction of the perichondrium and rib growth centers may lead to failure of subsequent chest wall development. A 29-year-old man who underwent a Ravitch operation 26 years previously developed a restrictive chest wall deformity, which resulted in severe pulmonary hypertension and restrictive lung disease.

Bilateral use of the vertical expandable prosthetic titanium rib attached to the pelvis: a novel treatment for scoliosis in the growing spine.

OBJECT: Few options exist for the treatment of severe, early onset scoliosis. Goals of treatment include stabilizing curve progression while allowing for normal spine, chest, and lung growth. The vertical expandable prosthetic titanium rib (VEPTR) is a novel device designed to control the spine deformity while permitting lung and spine growth. In this paper the authors report their experience with using bilateral VEPTRs from the ribs to the pelvis for children with severe, early onset scoliosis. METHODS: Eleven children were identified who had been treated with bilateral VEPTRs from the ribs to the pelvis. The authors conducted a retrospective review and collected the following data: clinical diagnosis, age at surgery, number of lengthening procedures, and complications. In addition, pre- and postoperative radiographs were reviewed to measure maximum Cobb angle (both thoracic and lumbar), thoracic height, total spine height as measured from T-1 to S-1, thoracic kyphosis (T2-12), and lumbar lordosis (L1-S1). RESULTS: The average patient age at surgery was 71 months; the mean preoperative thoracic Cobb angle was 81.7 degrees . This angle was corrected to 50.6 degrees immediately postoperatively, and this correction was maintained; at the most recent follow-up the curves averaged 58 degrees . Similarly, the preoperative kyphosis (T2-12) angle measured 43 degrees preoperatively, 23 degrees immediately postoperatively, and 37 degrees at the most recent follow-up evaluation. The patients underwent a total of 41 lengthening procedures (average 3.7 lengthening procedures per patient), and overall spine length increased from 23.1 cm preoperatively, to 27.3 cm immediately postoperatively, to 29.4 cm at the final follow-up (an average of 25 months). Four (36.4%) of the 11 patients experienced complications. CONCLUSIONS: The VEPTR offers a viable treatment option for children with severe, early onset scoliosis. It achieves and maintains spinal deformity correction, while allowing for continued spine and chest-wall growth. Complication rates are similar to those reported for other growing systems.

The effect of costal cartilage resection on the chest wall development: a morphometric evaluation.

OBJECTIVE: In repair of thoracic wall deformities, there is a debate in the literature regarding the optimal age and the type and number of costal cartilage resections. We evaluated the effect of costal cartilage resections on the chest wall development in young rabbits. METHODS: Fifty apparently healthy, 6 weeks of age, male New Zealand white rabbits were evaluated in five groups, each including 10 subjects. Group 1 served as control for the observation of normal thoracic development. Rabbits in group 2 underwent partial and rabbits in group 3 underwent total resections of the right third and fourth costal cartilages; those in group 4 underwent partial and rabbits in group 5 underwent total resections of the right third to sixth costal cartilages. Anteroposterior, horizontal and vertical diameters of the chest were measured before operation and repeated at 24 weeks of age. RESULTS: Upper and lower anteroposterior diameters of the thoracic wall and horizontal diameters of the left hemithorax differed significantly among groups (p=0.011, p=0.004, and p=0.002, respectively). Upper anteroposterior diameter was 49 mm in group 1 and 44 mm in group 3 (p=0.009). Lower anteroposterior diameter in group 5 (66 mm) was significantly less than that in group 1 (70 mm) (p=0.039) and there was also a statistically significant difference between group 4 (71 mm) and group 5 (66 mm) (p=0.002). Horizontal diameters of the left hemithorax in group 3 (32 mm; p=0.005) and 5 (32 mm; p=0.008) were significantly different when compared to group 1 (26 mm). Growth in right hemithorax was statistically less than that in left side in all operated groups except in group 2. CONCLUSIONS: Thoracic resections in young rabbits have demonstrated that the costal cartilage resection is not an innocent procedure as it severely affects the chest wall development especially in anteroposterior direction and the thoracic growth is markedly retarded when growth centers of the ribs are not preserved and/or four or more ribs are resected.

Evolution of anterior chest wall blood supply in female adolescents with progressive right-convex thoracic idiopathic scoliosis.

Breast asymmetry was believed to be related to the asymmetry of anterior chest wall blood supply and subsequently to etiology of idiopathic thoracic scoliosis in female adolescents. Recent investigations on the anterior chest wall blood supply with colour Doppler ultrasonography in such individuals did not show anatomic and hemodynamic abnormalities. The present study investigated the evolution of anterior chest wall blood supply in these individuals over a 2-year period. Twenty female adolescents with progressive right-convex idiopathic thoracic scoliosis (scoliotics), who were during the study in therapy with thoracolumbosacral orthosis and 20 age-matched girls, without spine deformity (controls) were studied with colour Doppler ultrasonography [internal mammary artery (IMA)] twice within the 2-year period. IMA-anatomic parameters [lumen diameter (D) and cross sectional area (AR)] and also hemodynamic flow parameters [time average mean flow velocity (TAM) and flow volume per minute (FV)] were measured. In the 2-year period of observation, thoracolumbosacral orthosis prevented scoliosis progression (P=0.004), whereas IMA-AR decreased bilaterally in the individuals of both groups (P<0.03). In the last evaluation: in scoliotics right IMA FV decreased (P<0.04), whereas in controls IMA FV decreased bilaterally (P<0.03); left IMA FV was significantly higher (P<0.05) in scoliotics than in controls. The significant, within the 2-year period, decrease of IMA-diameter, cross-sectional area, and flow volume seems to be a physiologic ageing process because it was observed in all individuals (scoliotics and controls) and thus these anatomic and hemodynamic changes seem not to have been affected by bracing. The maintenance of left flow volume of IMA in the prebrace levels in scoliotics was the most significant finding of this investigation. In conclusion, this study provided evidences for abnormalities in the evolution of anterior chest wall blood supply in female adolescents with progressive right-convex female thoracic scoliosis. Further studies are needed to investigate if this asymmetric blood evolution contributes to the development of this pattern of scoliosis in girls.

Colour Doppler ultrasonography for evaluation of anterior chest blood supply: the possible role of arterial blood supply to the costosternal junction in the aetiology of idiopathic scoliosis in female adolescents.

This prospective comparative study was carried out to investigate the blood supply to the anterior chest wall by measurement of several anatomical and haemodynamic flow parameters of the internal mammary artery, with the use of colour Doppler ultrasonography, in female scoliotics with idiopathic right convex scoliosis in adolescence. Previous investigations have postulated that asymmetry of the breasts in female adolescents may be linked with the development of right convex thoracic scoliosis. This breast asymmetry is supposed to be linked with anatomical and functional asymmetry of the internal mammary artery that is the main supplier to the mammary gland. However, no measurements of anatomical and haemodynamic parameters of the internal mammary artery have been made to justify or reject the hypothesis of asymmetric blood flow volume to the breasts and costosternal junction in female adolescent scoliotics. Twenty female adolescents with right convex thoracic scoliosis and 16 comparable female individuals without spine deformity were examined with roentgenograms (scoliotics only) to measure scoliosis curve, vertebral rotation and concave and convex rib-vertebra angle at three vertebrae (the apical, one level above and one below the apical vertebra). Doppler ultrasonography was used to measure, at the origin of the internal mammary artery, its lumen diameter, cross-sectional area, time average mean flow and flow volume per minute in scoliotics and controls, which were compared with each other. The roentgenographic parameters were compared with the ultrasonographic parameters in the scoliotics to disclose any relationship. The reliability of colour Doppler ultrasonography was high and the intra-observer variability low (ANOVA, P=0.92-0.94). There was no statistically significant difference in the ultrasonographic parameters of the internal mammary artery between right and left side in each individual as well as between scoliotics and controls. In scoliotics the right mammary artery time average mean velocity increases with the convex ( P<0.05) and concave ( P<0.01) rib-vertebra angle one level above the apical vertebrae and with the apical convex rib-vertebra angle ( P<0.05). The right internal mammary artery flow volume per minute increases with convex ( P<0.01) and concave ( P<0.01) rib-vertebra angle one level above the apical vertebrae and with the apical convex rib-vertebra angle ( P<0.05). Left internal mammary artery cross-sectional area increases with convex apical rib-vertebra angle ( P<0.01) and concave rib-vertebra angle one level above the apical vertebra ( P<0.01). Conclusively, this investigation showed that haemodynamic flow parameters of the right internal mammary artery and anatomical parameters of the left internal mammary artery are significantly correlated with the magnitude of rib-vertebra angles close to the apex of right thoracic scoliosis in female adolescents. This study did not find any evidence for side-difference in vascularity of the anterior thorax wall and, thus, it could not clearly justify previous theories for development of right thoracic scoliosis in female adolescents.