Quantification of Bending Tolerance of the Cartilaginous Nasal Septum: Computer-Based Measurements (original) (raw)
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Journal of Medical Engineering, 2013
Background. With the current lack of clinically relevant classification methods of septal deviation, computer-generated models are important, as septal cartilage is indistinguishable on current imaging methods, making preoperative planning difficult.Methods. Three-dimensional models of the septum were created from a CT scan, and incremental forces were applied.Results. Regardless of the force direction, with increasing force, the septum first tilts (type I) and then crumples into a C shape (type II) and finally into an S shape (type III). In type I, it is important to address the dislocation in the vomer-ethmoid cartilage junction and vomerine groove, where stress is concentrated. In types II and III, there is intrinsic fracture and shortening of the nasal septum, which may be dislocated off the anterior nasal spine. Surgery aims to relieve the posterior buckling and dislocation, with realignment of the septum to the ANS and possible spreader grafts to buttress the fracture sites.Co...
Defining Nasal Cartilage Elasticity
Archives of Facial Plastic Surgery, 2007
To define the modulus of elasticity for nasal septum, auricular, upper lateral, and lower lateral cartilages. Methods: Prospective enrollment of sequential patients undergoing septorhinoplasty. Test samples were obtained through routine surgical interventions using atraumatic harvesting techniques. The modulus of elasticity was determined using a customized biomechanical testing device. A clinical analysis of nasal tip strength and "ethnic" nasal categorization was performed. Results: Five sequential patients were enrolled; 4 underwent biomechanical testing of harvested cartilage. All 4 patients were classified as having a leptorrhine nasal architecture. The modulus of elasticity for the lower lateral cartilages was 1.82 to 15.28 MPa. Values for auricular, nasal septum, and upper lateral cartilages (medial and caudal) were also determined. Conclusions: This is the first biomechanical study performed on human auricular, lower lateral, and upper lateral cartilages. The elastic modulus can be determined from samples obtained during routine septorhinoplasty. The modulus of elasticity for all areas was significantly higher than values previously demonstrated for bioengineered elastic cartilage and carved human nasal septal specimens. Shaving the lateral portions of the nasal septum may significantly reduce tensile strength, which may affect graft performance in vivo. Further refinement of testing methods and an increase in the number of analyzed samples are required for formal statistical analysis and further determination of clinical relevance in different nasal subtypes.
Deformation of nasal septum during nasal trauma
The Laryngoscope, 2010
Background: Injury to the nasal septum is commonly found in most nasal fractures. The nasal septum deforms and crumples, leading to nasal deviation and internal nasal obstruction. Aim: This study aims to identify the main areas of high stress concentration when a dynamic anteroposterior load is applied to the nasal tip, simulating nasal trauma. We wish to determine if the nasal septum acts as a crumpled zone, and deforms significantly during nasal trauma. Materials and Methods: An idealized and a patient-specified finite element model have been generated for the present study. Several models with various combinations of narrower angle at the Vomer Ethmoidal Junction (VEJ) are also constructed from this septum model. Finite element analyses are carried out to determine the deformation and stress distribution in the nasal septum when a dynamic anteroposterior load is applied to the nasal tip. Conclusions: The maximum stress areas in the nasal septum are in the vicinity of the bony-cartilaginous (BC) junction and the anterior nasal spine (ANS), which are consistent with clinical experience. A larger anteroposterior load, a longer loading duration, and a more acute VEJ angle would result in higher maximum stresses. The observations were identical in both idealized and patient-specific models. The findings of this analysis also suggest that the septum does function as a crumpled zone, absorbing a significant amount of stress before it is transmitted to the skull.
Biomechanics of the deformity of septal L‐Struts
The Laryngoscope, 2010
Objectives/Hypothesis: A septal L-strut is often preserved or created during septoplasty. The main intention is to provide structural stability and to straighten the nasal septum. Deformity or excessive deformation of the L-strut might cause functional or aesthetic complications. The objectives were to examine the effects of material properties, the boundary conditions, the nasal tip support, and the geometry of the L-struts on the deformity of septal L-struts. Study Design: Computer-aided modeling was used to create a spring-supported nasal tip and free nasal tip L strut septal cartilage models upon which simulation was performed to analyse the deformation patterns. Methods: A five-sided septum model was first created from the computed tomography scan of a human subject. Several models with various combinations of wider or narrower dorsal struts as well as arc of cartilage were then constructed from this septum model. The edges connected to bony supports were assumed to be fixed, and the nasal tip was assumed to be spring supported. Finite element analyses were carried out to determine the deformation and stress distribution in the septal strut for different combinations of material properties and nasal tip spring support. Results: The spring-supported nasal tip model provides a more accurate representation of the boundary conditions in the nose. In both the free and spring-supported nasal tips-the BC junction and the nasal spine are found to be the consistent points of maximum stress regardless of material properties. The preservation of an arc of cartilage and a wider dorsal strut increase the stability of the structure. Conclusions: The introduction of a spring-supported nasal tip model provided a more accurate representation of the boundary conditions in the nose. The bony-cartilaginous junction and the nasal spine were found to be the consistent points of maximum stress, regardless of material properties. The preservation of an arc of cartilage and a wider dorsal strut increased the stability of the structure.
Relationship between the degree and direction of nasal septum deviation and nasal bone morphology
Head & Face Medicine, 2017
Background: Nasal septal deviation may affect nasal bone growth and facial morphology. Knowledge of nasal morphologic parameters may plays an important role in planning successful rhinoplasty and septoplasty operation. The aim of our study was to evaluate the relationship between the direction and degree of nasal septal deviation with nasal bone morphology, along with factors such as age and gender. Methods: Maxillofacial computed tomography (CT) of 250 patients with nasal septal deviation was analyzed retrospectively in this study. We excluded patients with factors that could affect their nasal bone morphology, and a total of 203 patients (111 males, 92 females; mean age, 36.23 years; age range, 18-79 years) were evaluated. The nasal deviation angle was measured on coronal CT images as the angle between the most deviated point of the septum, and the midline nasal morphology was determined by measuring nasal length, internasal angle and lateral and intermediate nasal thickness on both sides. Results: The deviation of nasal septum has been detected as to the right in 107 patients (52.7%) and to the left in 96 patients (47.3%). Lateral and intermediate nasal bone thickness and nasal bone length were significantly greater on the ipsilateral deviation side (Table 3). No significant correlation was found between the variation of the nasal deviation angle and nasal bone morphology (Table 4). There were significant differences between the sexes for all investigated parameters except for the nasal deviation angle (p = 0.660). We found that the only internasal angle increases with aging (p = 0.002). Conclusion: The study shows that the direction of nasal septal deviation may be a factor that affects nasal bone morphology.
An algorithm for management of nasal caudal septal deformities
The Egyptian Journal of Otolaryngology, 2019
Introduction Caudal end septal deformities are common deformities. Trauma is a main cause of these deformities. there is lack of an algorithm for choosing the suitable technique for the type of deformity. The aim of this retrospective study was to put an algorithm for approaching different caudal end deformities. Patients and methods Retrospective review of 136 patients underwent surgical correction for caudal end deformities. Data collection included functional breathing outcomes and drawbacks of different techniques as postop caudal end sublaxation and firm nasal tip sensation. Results Patients were divided into 4 groups (according to the technique by which the caudal end of nasal septum was managed) as following: Group A: 90 patients who had undergone surgeries with swinging door or modified swinging door techniques with fixation to anterior nasal spine technique, Group B: 26 patients who had undergone surgery with tongue in groove technique, Group C: 10 patients who had undergon...
International Journal of Otorhinolaryngology and Head and Neck Surgery, 2020
The nasal septum provides support for the portion of cartilaginous nasal dorsum, and it is responsible for determining the projection of the nasal tip. Septal cartilage plays an important role as a donor graft material in modern rhinoplasty. An anatomical study was performed on 10 adult cadavers. The excised septal cartilage was placed on grid paper; digital images were taken; all septal cartilage was divided into nine equivalent quadrants; and quantitative measurements for length, height, and area were calculated and compared. The average length of the septum was 35.8 mm, while the average height was 25.9 mm. The average septal area was 679.7 mm 2 . The septal thickness mean values were analysed in nine quadrants, ranging from 1.21 to 2.08 mm. Specifically, the central and cranial areas were thickest, and the area corresponding to the L-strut was thinnest. Anatomical variations of the thickness of septal cartilage excisions were found to be statistically significant, and these diff...
Characterization of Injury Induced by Routine Surgical Manipulations of Nasal Septal Cartilage
JAMA Facial Plastic Surgery, 2019
IMPORTANCE This study characterizes and compares common surgical manipulations' effects on septal cartilage to understand their implications for rhinoplasty outcomes based on cell viability and cartilage health. OBJECTIVE To illustrate distinct differences in the impact of various surgical manipulations on septal cartilage in an in vitro septal cartilage model. A secondary objective is to better understand the chondrocyte's response to injury as well as how alterations in the extracellular matrix correspond to chondrocyte viability. DESIGN, SETTING, AND PARTICIPANTS In this bench-top in vitro porcine model using juvenile bovine septal cartilage from bovine snouts, easily obtainable septal cartilage was used to generate large numbers of homogenous cartilage specimens. Quantitative outcomes at early and late time points were cell viability, cell stress, matrix loss, and qualitative assessment through histologic examination. The study was performed at a single academic tertiary care research hospital. INTERVENTIONS Four common surgical manipulations were contrasted with a control group: crushed cartilage, scored cartilage, diced cartilage, and shaved cartilage. MAIN OUTCOMES AND MEASURES Following the manipulation of the cartilage, the quantitative outcomes were glycosaminoglycan release to the media, lactate dehydrogenase release to the media, and cell death analysis through apoptosis staining. The qualitative outcomes were histologic staining of the manipulated cartilage with safranin-O/fast green stain to identify proteoglycan loss. RESULTS The crushing followed by shaving manipulations were the most damaging as indicated by increased levels of lactate dehydrogenase release, glycosaminoglycans loss, and cell death. Matrix loss did not increase until after 48 hours postinjury. Furthermore, chondrocyte death was seen early after injury and accelerated to the late time point, day 9, in all manipulations. Conversely, cell stress was found to be greater at 48 hours postinjury, which then declined to the late time point, day 9. CONCLUSIONS AND RELEVANCE The crushing manipulation followed by shaving and then dicing were the most destructive methods of cartilage manipulation relative to control specimens. Collectively, these outcomes demonstrate the range of injury which occurs with all septal cartilage manipulations and can inform rhinoplasty practice to use the least damaging effective surgical manipulation to obtain the desired outcome. LEVEL OF EVIDENCE NA.