Warping Characteristics of Rib Allograft Cartilage.

When septal cartilage is lacking, commercially available costal cartilage allograft can be used. Such allografts have "off-the-shelf" accessibility, are available in multiple sizes, are aseptically processed to meet sterility, and are screened to minimize infectious risks. The purpose of this study was to evaluate the effect of donor age, storage temperature, and orientation of a bilayered construct on the degree of warping of a commercialized fresh frozen costal cartilage allograft in vitro over time. A total of 140 fresh frozen costal cartilage cadaveric specimens were separated into three donor age groups. These were allocated into three harvesting subgroups: group a, single pieces (cephalocaudal segments); group b, two laminated pieces of the same rib sutured together in anatomical position (laminated group); and group c, two pieces from the same rib reversed onto each other and sutured together (oppositional group). Photographs were examined and analyzed to determine the degree of cartilaginous warping. Decreased rates of warping were seen in commercially available, aseptically processed costal cartilage allografts procured from older cadavers. Warping was also decreased when oppositional suturing techniques were used as a way to address those intrinsic cartilage forces.

Sonoelastographic Evaluation of the Lower Lateral Nasal Cartilage Lateral Crus, Auricular Conchal Cartilage, and Costal Cartilage.

We investigated the sonoelastographic features of the lower lateral nasal cartilage lateral crus (LLNC-LC), auricular conchal cartilage (ACC), and costal cartilage (CC). In this prospective study, group 1 consisted of 60 participants (30 males and 30 females) between 18 and 35 years of age. Group 2 consisted of 60 participants (30 males and 30 females) between 35 and 50 years of age. Strain elastography (SE) and shear wave elastography (SWE) were performed. For all LLNC-LCs and ACCs, type I SE was detected more in group 2, type II SE was detected more in group 1, and type III SE was detected more in group 1 (p < 0.05). For CC, type I SE was detected more in both groups (p < 0.05). For LLNC-LC, type I SE was detected more in males compared with females in both groups (p < 0.05). For all LLNC-LC, ACC and CC, the SWE modulus of group 2 was significantly higher than that of group 1 (p < 0.05). In older participants, the SWE modulus increased. We recommend using ACC mainly in rhinoplasty operations for primary and revision cases as its SWE modulus is similar to that of the LLNC-LC. However, due to the higher SWE modulus of CC, CC grafts should not be used as the first choice in rhinoplasties, especially in the reconstruction of the nasal tip contour, but may be used in nasal dorsum augmentation.

Estimating Age at Death Based on Costal Cartilage Calcification.

Age estimation is a crucial part of forensic investigations. Because different parts of the body are often found at crime scenes, it is important to explore the regions that can be used for age estimation. Previous studies have used simple X-ray to analyze changes in costal cartilage calcification as a measure of age. Here, we tested whether age could be better estimated using measurements of costal cartilage calcification on postmortem CT images. In this study, male and female decedents (n = 10 each) from autopsy cases were grouped into 10-year incremental age groups (20-29 y; 30-39 y; up to 89 y). We found that the mean Hounsfield unit (CT number) and percentage calcification (the ratio of the ossified area to the whole area) increased with age for both sexes. However, there were marked individual differences within many of the groups, and this led to a statistically significant difference (P < 0.05) only between the 20-29 y group and the older age groups. To improve the ability to correctly assign cases to age groups, we introduced and reanalyzed the data using Bayesian statistics. This improved the classifications rates, with 40% of males and 35% of females correctly assigned into their age groups. Broadening the age range could further improve the number of matches. Thus, combining Bayesian statistics with CT imaging can be used to estimate age at death from costal cartilage calcification, and could be used as an adjunct in forensic investigations.

Characteristics of Chinese Costal Cartilage and Costa Calcification Using Dual-Energy Computed Tomography Imaging.

To assess characteristics of Chinese costal cartilage and costa calcification using Dual-Energy computed tomography(DECT). 154 patients who underwent chest DECT scanning were included in our study. They were divided into following groups: less than 30 years old, 31-40 years old, 41-50 years old, 51-60 years old and over 60 years old. The sixth, seventh and eighth costal cartilages and costas were evaluated. Calcification patterns of cartilage were classified as central(C), peripheral(P), mixed(M) and no calcification(N) types. Calcification degree of cartilage was distinguished as 1(0-25%), 2(26-50%) and 3(>50%). CT value, calcium and water concentrations were measured in costal cartilage, cortical or cancellous bone respectively. An increasing C pattern of cartilage was displayed in females, while P type preferred in males as age increased. Calcification degree generally changed from 1 to 2 or 3 in females. CT value and calcium concentration of cartilage went through a gradual rising course and peaked in their 40-50 years, while those two indices of cancellous bone decreased gradually since their 50 years in females. The findings suggest a gradual calcification of the costal cartilage took place before 40-50 years old and a sharp bone loss of the costa happened after 40-50 years old in females.

Characterizing viscoelasticity of unhydrolyzed chicken sternal cartilage extract suspensions: Towards development of injectable therapeutics formulations.

Exogenous delivery of cartilage extract is being explored as a promising candidate for knee arthritis treatment as it biomimics native cartilage tissue characteristics. In this study, we report on the rheological characterization of aqueous suspensions constituted from a powdered form of unhydrolyzed chicken sternum extract. The effect of particle size (as-received vs. milled), suspension fluid (water vs. PBS), and temperature (37°C vs. 4°C), on the viscoelastic properties of the sternum extract based particulate suspensions were evaluated. Results showed that these suspensions exhibit shear-thinning characteristics as shear rate (γ̇) increases, while viscosity (η), storage (G'), and loss (G″) moduli of the suspensions increased with increasing particulate loading (ϕ: 2.5-10wt%). Reducing the as-received particle size by milling decreased G', G, and η of the suspensions and increased the influence of ϕ on these properties, possibly due to improved particle packing. Replacing water with PBS had no significant effect on the rheological properties, but temperature reduction from 37°C to 4°C increased G', G", and η of the suspensions and lowered the impact of powder loading on viscoelastic properties. The suspension's time-dependent response was typical of viscoelastic materials, characterized by an asymptotical approach to a final stress (stress relaxation) or strain (creep). Results were fit to a power-law model for creep, a general relaxation model for exponential decay in stress, Carreau-Yasuda models for flow curves, and a two-parameter Liu model to identify the maximum powder loading (ϕm). Among the various forces involved in particle-particle interactions within these suspensions, electrostatic forces appeared to dominate the most. Such characterization of the viscoelastic nature of these suspensions would help in formulating stable injectable cartilage extract based therapeutics for in vivo applications.

Viability and Biomechanics of Bare Diced Cartilage Grafts in Experimental Study.

OBJECTIVE: To assess the viability and biomechanics of bare diced cartilage grafts. METHODS: Cartilage samples were collected from 1 ear in 15 rabbits as well as costal cartilage. Each rabbit was inserted bare diced- and single-strip costal-cartilage grafts, respectively, into paraspinal subcutaneous pockets: after euthanasia at 2 months, specimens were weighed, with diced cartilage grafts examined histomorphologically by hematoxylin-eosin staining, masson trichrome staining, and immunohistochemistry. Finally, biomechanical properties of grafts were assessed. RESULTS: Bare diced cartilage grafts were connected into an integrated mass after 2 months, and inward growth of fibrous tissues and angiogenesis were observed. Mean wet weights of diced cartilage grafts were 1.603 ±â€Š0.278 and 1.662 ±â€Š0.204 g pre- and postoperation, respectively; those of costal cartilage grafts were 0.053 ±â€Š0.008 and 0.058 ±â€Š0.008 g, respectively. In compression assays, mean modulus values of elasticity at yield in diced- and costal-cartilage grafts were 7.65 ±â€Š0.59 and 22.30 ±â€Š1.15 MPa, respectively (P < 0.05); mean stress values were 4.07 ±â€Š0.38 and 12.50 ±â€Š1.15 MPa, respectively (P < 0.05). In the tensile test, mean modulus values of elasticity at yield of diced- and costal-cartilage grafts were 4.70 ±â€Š0.78 and 10.59 ±â€Š1.39 MPa, respectively (P < 0.05), mean stress values were 0.82 ±â€Š0.05 and 1.76 ±â€Š0.21 MPa, respectively (P < 0.05). CONCLUSIONS: Diced cartilage grafts had favorable viability and growth. Despite reduced elasticity and stress values, they still can be served as substitute for supportive filling materials.

Effects of platelet-rich plasma on cartilage regeneration after costal cartilage resection: a stereological and histopathological study.

BACKGROUND: In cases of congenital chest wall deformities, it is important to maintain the flexibility of the chest wall after rib cartilage resection. In this study, we aimed to determine the regeneration capability of cartilage and the effects of platelet-rich plasma (PRP) on the regeneration process. METHODS: A total of 16 four-week-old New Zealand rabbits were used in this study. In the 4th-5th right costal cartilages, the perichondrial sheaths were dissected and costal cartilages were excised. Then, the perichondrial sheaths were closed with absorbable material in the sham group (n = 8), and this was done after replacing PRP in the PRP group (n = 8). The left costal cartilages of the animals were used as controls. The volumes of the costal cartilages and their perichondrial sheaths were estimated using Cavalieri's principle. In addition, the mean numerical densities of the chondroblasts and chondrocytes per square millimetre were estimated using unbiased counting frames. RESULTS: In the PRP and sham groups, the volumes of the cartilages and perichondrial sheaths were higher than those of the control group (p < 0.05). The numerical densities of the chondroblasts and chondrocytes increased more in the PRP group than in the sham group (p < 0.05). CONCLUSIONS: Applying PRP after resection may provide better healing and faster regeneration of cartilage.

Costal Cartilages Do Not Overgrow in Patients with Pectus Excavatum.

OBJECTIVE: The purpose of this study was to determine whether or not patients with pectus excavatum (PE) exhibit costal cartilage overgrowth compared to normal subjects. MATERIALS AND METHODS: The computed tomography acquisitions of 32 patients with PE and 35 normal controls were analyzed. On axial images the length of the 4th-7th costal cartilages was measured to calculate the Haller index. The ratio between the length of the cartilages and the median of the transverse and longitudinal thorax diameters were recorded to account for anatomical variability. The length of the cartilages was compared between the PE and control subjects using the independent-samples t test. For patients with asymmetric PE the length of the 4th-7th costal cartilages was compared between the rotated and nonrotated sides. RESULTS: The mean transverse and coronal thorax diameters were 233.29 ± 24.47 and 231.69 ± 22.47 mm for PE patients and 252.67 ± 37.25 and 238.64 ± 27.40 mm for controls, respectively, with no significant differences between the two groups (p = 0.816 and 0.145). The mean sagittal diameter (59.30 ± 14.21 mm) and Haller index (4.02 ± 1.34) in the PE group were significantly different from the controls (107.34 ± 19.59 and 2.2 ± 0.54 mm, respectively; p = 0.00). Actual and relative lengths of costal cartilages were similar in both PE subjects and controls for all 4 costal cartilages measured. In subjects with asymmetric PE, both relative and absolute costal cartilage lengths were similar on the rotated and nonrotated side. CONCLUSIONS: The length of the 4th, 5th, 6th and 7th costal cartilages was similar in PE patients and the control subjects. These was also similar between the rotated and nonrotated sides of the sternum in patients with asymmetric PE.

[Experimental study of the influence of expanded capsule on biomechanics of autograftedcostal cartilage].

OBJECTIVE: To explore the effect of the expanded capsule on biomechanics of the transplanted autologous costal cartilage. METHODS: Ten New Zealand white rabbits aged 3 months were involved and four 15 ml tissue expanders were implanted symmetrically on the back of each rabbit. After 1 month, expanded capsules were removed (experimental group) on the left side and were reserved (control group) on the right side. Meanwhile, the 6th and 7th costal cartilage without the perichondrium were taken out and each cartilage was divided into two pieces and put under the expanded capsule symmetrically. The cartilage at the upper sides and lower sides were taken out at 4 weeks and 8 weeks later, respectively. All the cartilages were sculptured for the demand of the machine text. The tension and compression property of the cartilages were assessed by the material testing machine (Instron 5967) and the results were analyzed statistically. RESULTS: 8 weeks lateral, the average ultimate tension strength was (4. 954 + 2. 8) MPa in experimental group and (2.939 + 0.842) MPa in control group. The average compressive strength was (58.74 ± 13.77) MPa in experimental group, and (47.61 ± 11.41) MPa in control group. The biomechanics property of the cartilages in the experimental group is better than the control group, and the differences were statistically significant. CONCLUSIONS: Removing the expanded capsule is benefical to maintain the biomechanics of autologous costal cartilage.

Handheld-Level Electromechanical Cartilage Reshaping Device.

We have developed a handheld-level multichannel electromechanical reshaping (EMR) cartilage device and evaluated the feasibility of providing a means of cartilage reshaping in a clinical outpatient setting. The effect of EMR on pig costal cartilage was evaluated in terms of shape change, tissue heat generation, and cell viability. The pig costal cartilage specimens (23 mm × 6.0 mm × 0.7 mm) were mechanically deformed to 90 degrees and fixed to a plastic jig and applied 5, 6, 7, and 8 V up to 8 minutes to find the optimal dosimetry for the our developed EMR device. The results reveal that bend angle increased with increasing voltage and application time. The maximum bend angle obtained was 70.5 ± 7.3 at 8 V, 5 minutes. The temperature of flat pig costal cartilage specimens were measured, while a constant electric voltage was applied to three pairs of electrodes that were inserted into the cartilages. The nonthermal feature of EMR was validated by a thermal infrared camera; that is, the maximum temperate of the flat cartilages is 20.3°C at 8 V. Cell viability assay showed no significant difference in cell damaged area from 3 to 7 minutes exposure with 7 V. In conclusion, the multichannel EMR device that was developed showed a good feasibility of cartilage shaping with minimal temperature change.

Micromechanical modeling of calcifying human costal cartilage using the generalized method of cells.

Various tissues in the human body, including cartilage, are known to calcify with aging. There currently is no material model that accounts for the calcification in the costal cartilage, which could affect the overall structural response of the rib cage, and thus change the mechanisms and resistance to injury. The goal of this study is to investigate, through the development of a calcifying cartilage model, whether the calcification morphologies present in the costal cartilage change its effective material properties. A calcified cartilage material model was developed using the morphologies of calcifications obtained from microCT and the relaxed elastic modulus of the human costal cartilage obtained from indentation testing. The homogenized model of calcifying cartilage found that calcifications alter the effective material behavior of the cartilage, and this effect is highly dependent on the microstructural connectivity of the calcification. Calcifications which are not contiguous with the rib bone and constitute 0-18% of the cartilage volume increase the effective elastic modulus from its baseline value of 5MPa to up to 8MPa. Calcifications which are attached to the rib bone, which typically constitute 18-25% of the cartilage volume, result in effective moduli of 20-66MPa, depending on the microstructure, and introduce marked anisotropy into the material. The calcifying cartilage model developed in this study can be incorporated into biomechanical models of the aging thorax to better understand how calcifications in the aging thorax affect the structural response of the rib cage.