Rib overgrowth may be a contributing factor for pectus excavatum: Evaluation of prepubertal patients younger than 10years old.

BACKGROUND/PURPOSE: We compared the costal cartilage and rib length between prepubertal patients with symmetric pectus excavatum and age- and sex-matched controls without anterior chest wall depression to evaluate if rib overgrowth is a contributing factor for pectus excavatum METHODS: The sample included 18 prepubertal patients <10years old with symmetric pectus excavatum and 18 age-and sex-matched controls without chest wall deformity. The full lengths of the fourth to sixth ribs and costal cartilage were measured using three-dimensional volume-rendered computed tomography and curved multiplanar reformatting techniques. The rib and costal cartilage lengths, total combined rib and costal cartilage length, and costal index ([length of cartilage/length of rib]×100 [%]) at the fourth to sixth levels were compared between the groups. RESULTS: The rib lengths in the patient group were significantly longer than in the control group for the 6th right rib and 4th, 5th, and 6th left ribs. The costal cartilage lengths and costal indices were not different between two groups. CONCLUSIONS: In patients with symmetric pectus excavatum aged <10years old, several of the ribs were longer than those of controls, suggesting that abnormal rib overgrowth may be a contributing factor responsible for pectus excavatum rather than cartilage overgrowth.

Deletion of IFT80 Impairs Epiphyseal and Articular Cartilage Formation Due to Disruption of Chondrocyte Differentiation.

Intraflagellar transport proteins (IFT) play important roles in cilia formation and organ development. Partial loss of IFT80 function leads Jeune asphyxiating thoracic dystrophy (JATD) or short-rib polydactyly (SRP) syndrome type III, displaying narrow thoracic cavity and multiple cartilage anomalies. However, it is unknown how IFT80 regulates cartilage formation. To define the role and mechanism of IFT80 in chondrocyte function and cartilage formation, we generated a Col2α1; IFT80f/f mouse model by crossing IFT80f/f mice with inducible Col2α1-CreER mice, and deleted IFT80 in chondrocyte lineage by injection of tamoxifen into the mice in embryonic or postnatal stage. Loss of IFT80 in the embryonic stage resulted in short limbs at birth. Histological studies showed that IFT80-deficient mice have shortened cartilage with marked changes in cellular morphology and organization in the resting, proliferative, pre-hypertrophic, and hypertrophic zones. Moreover, deletion of IFT80 in the postnatal stage led to mouse stunted growth with shortened growth plate but thickened articular cartilage. Defects of ciliogenesis were found in the cartilage of IFT80-deficient mice and primary IFT80-deficient chondrocytes. Further study showed that chondrogenic differentiation was significantly inhibited in IFT80-deficient mice due to reduced hedgehog (Hh) signaling and increased Wnt signaling activities. These findings demonstrate that loss of IFT80 blocks chondrocyte differentiation by disruption of ciliogenesis and alteration of Hh and Wnt signaling transduction, which in turn alters epiphyseal and articular cartilage formation.

Overgrowth of costochondral grafts in craniomaxillofacial reconstruction: Rare complication and literature review.

OBJECTIVE: Costochondral grafts (CCGs) have been used for the reconstruction of the craniomaxillofacial defects in various situations. However, there is controversy concerning the growth pattern of CCGs, which is often unpredictable and may manifest as overgrowth or no growth at all. This article summarizes the literature concerning overgrowth of CCGs in craniomaxillofacial reconstruction, and presents an uncommon case of treatment for overgrowth of costal graft in mandibular body reconstruction. MATERIAL AND METHODS: The literature on overgrowth of CCGs in craniomaxillofacial reconstruction was reviewed with a chart. A 25-year-old man received mandibular partial resection because of adamantoblastoma, followed by replacement of costal graft. Two years postoperatively, he began to present with facial asymmetry and malocclusion. Clinical and radiologic image examination showed deviation of the chin to the left side, and overgrowth of the costal graft was diagnosed. Left sagittal split ramus osteotomy (SSRO), genioplasty, and left mandibular angle ostectomy (MAO) were performed. RESULTS: A total of 30 articles containing 68 cases of overgrowth of CCGs in craniomaxillofacial reconstructions have been reported since 1977, including the present case. During a 2-year follow-up, the patient's postoperative facial profile and contour appeared stable clinically and radiographically, and an improved symmetry facial contour and occlusion were achieved. CONCLUSION: The growth of CCGs may be influenced by complex factors such as the function of the mandible, inherent growth capacity, and possibly hormonal factors. Once overgrowth of the costal graft occurs in mandibular body reconstruction, SSRO combined with genioplasty and MAO could be the optimal option to restore a symmetrical face.

A Cross-Sectional Study of Chest Wall Development in Patients with Pectus Excavatum.

BACKGROUND: We conducted a cross-sectional study to quantify the developmental changes of the thoracic cage in patients with pectus excavatum (PE). METHODS: The preoperative posteroanterior standing chest radiographs (chest PAs) of 1,197 consecutive patients with PE, together with 1,661 age- and sex-matched minor surgery patients, as a control group, who were seen between June 2005 and February 2013, were reviewed. The maximum width of each rib pair and chest height (H) were measured on the chest PA. RESULTS: In the PE group, the normal thoracic contour in younger patients was replaced by a characteristic can-shaped chest wall, which showed protrusion of the upper ribs, an increased H, and a straightened lateral border of the chest cage, as they grew into adulthood. The chest height difference between the PE and control groups increased progressively, from the age of 8 years and most significantly from age 13 to 17 years. No difference was observed in the middle and lower rib widths. Sex did not influence these trends. CONCLUSION: The PE chest wall shows a significant increment in chest height, and upper rib width starts during the period of rapid growth and is maintained into adulthood. The thoracic deformity in patients with PE includes more than just the sternal deformity.

Asymmetric Pectus Excavatum Is Associated with Overgrowth of Ribs Rather Than Cartilage.

BACKGROUND: To evaluate whether the overgrowth of costal cartilage exists in patients with pectus excavatum, we compared the length of the costal cartilage and ribs between patients with asymmetric pectus excavatum and controls without chest wall deformity using three-dimensional computed tomography. MATERIALS AND METHODS: Nineteen adult patients with asymmetric pectus excavatum and 19 age and sex matched controls without chest wall deformity were enrolled. We measured the full lengths of the fourth to sixth ribs and costal cartilage using three-dimensional volume-rendered computed tomography images and curved multiplanar reformatting techniques. The lengths of ribs and costal cartilage, their summations, and the costal index ([length of cartilage/length of rib] × 100 [%]) were compared on the asymmetrically depressed side of patients (Group A), the opposite side of the same patients (Group B), and controls (Group C) at the fourth to sixth levels. RESULTS: The lengths of the ribs of groups A and B were significantly longer (p < 0.001) than those of group C (299.4 ± 14.9 mm vs. 302.9 ± 15.3 mm vs. 288.9 ± 12.2 at the fourth level, 312.3 ± 14.1 mm vs. 318.4 ± 14.6 mm vs. 303.2 ± 12.7 mm at the fifth level, and 322.2 ± 17.2 mm vs. 325.2 ± 17.5 mm vs. 309.4 ± 12.3 mm at the sixth level). The costal cartilage lengths did not differ (p > 0.05) among the three groups (53.1 ± 7.3 mm vs. 54.6 ± 8.6 mm vs. 52.9 ± 5.2 at the fourth level, 71.9 ± 9.6 mm vs. 72.3 ± 9.9 mm vs. 69.2 ± 7.1 mm at the fifth level, and 100.1 ± 15.2 mm vs. 104.2 ± 15.8 mm vs. 99.1 ± 9.1 mm at sixth level). The summations of the rib and costal cartilage lengths were longer in groups A and B than in group C. The costal indices were not different among the three groups at the fourth, fifth, and sixth rib levels. CONCLUSION: In patients who had asymmetric pectus excavatum with a ≥ 21-degree angle of sternal rotations, the ribs but not the costal cartilage were longer than those of controls. These findings suggest that cartilage overgrowth is not the main factor responsible for asymmetric pectus excavatum, and it could instead be related to abnormal rib growth.

The etiology of pectus carinatum involves overgrowth of costal cartilage and undergrowth of ribs.

PURPOSE: We compared the length of costal cartilage and rib between patients with symmetric pectus carinatum and controls without anterior chest wall protrusion, using a 3-dimensional (3D) computed tomography (CT) to evaluate whether the overgrowth of costal cartilage exists in patients with pectus carinatum. SUBJECTS AND METHODS: Twenty-six patients with symmetric pectus carinatum and matched twenty-six controls without chest wall protrusion were enrolled. We measured the full lengths of the 4th-6th ribs and costal cartilages using 3-D volume rendering CT images and the curved multiplanar reformatted (MPR) techniques. The lengths of ribs and costal cartilages, the summation of rib and costal cartilage lengths, and the costal index [length of cartilage/length of rib * 100 (%)] were compared between the patients group and the control group at 4th-6th levels. RESULTS: The lengths of costal cartilage in patient group were significantly longer than those of control group at 4th, 5th and 6th rib level. The lengths of ribs in patient group were significantly shorter than those of control group at 4th, 5th and 6th rib level. The summations of rib and costal cartilage lengths were not longer in patients group than in control group. The costal indices were significantly larger in patients group than in control groups at 4th, 5th and 6th rib level. CONCLUSION: In patients with symmetric pectus carinatum, the lengths of costal cartilage were longer but the lengths of rib were shorter than those of controls. These findings may supports that the overgrowth of costal cartilage was not the only factor responsible for pectus carinatum.

The role of CT analyses of the sternal end of the clavicle and the first costal cartilage in age estimation.

The ossification patterns of medial clavicle and the first costal cartilage represent interesting features of the same anatomical region which are accessible for conventional radiographic and computed tomography (CT) examinations in the same field of view. This study encompassed Serbian population and was carried out to examine whether CT analyses of medial clavicle and the first costal cartilage could be successfully applied, either individually or conjointly, in the age assessment. The study was based on CT examinations of thoracic region of 154 patients, aged between 15 and 35 years. Besides radiodensity and stages of epiphyseal cartilage ossification of medial clavicle, the study detected other features that expressed significant correlation with age, such as calculated anterior to posterior cortical thickness ratio, medullar canal diameter, and clavicular shaft diameter. However, although calculated ossified and calcified linear projections' (OCP) stages correlated to age, the distinction between stages was not satisfying. The interaction between the ossification status of medial clavicle and OCP was not significantly influenced by age. The results of our study outlined interesting new age predictors with mutual relationship: acquired radio density of the sternal epiphyseal-metaphyseal region and radio density of the first costal cartilage. Intersex variability was observed in several age-related features: calculated anterior to posterior cortical thickness ratio, diameter of medullar canal, and diameter of the clavicular shaft. Altogether, our study identified several radiological features of the first costal cartilage and medial clavicle that correlated with age and which could be applied as additional guidance for age estimation in each specific case.