[Clinical characteristics, diagnosis and treatment of nasal cartilage mesenchymal hamartoma in infants].

Objective: To explore the clinical characteristics, pathological features, and diagnosis and treatment strategies of nasal chondromesenchymal hamartoma (NCMH) in infants and young children. Methods: A retrospective analysis was conducted on seven cases of NCMH infants and young children admitted to Beijing Children's Hospital, Capital Medical University from April 2015 to January 2022. The cohort included 5 males and 2 females, aged from 6 days to 2 years and 3 months. General information, clinical symptoms, imaging findings, treatment plans, postoperative complications, recurrence and follow-up time were collected, summarized and analyzed. Additionally, immunohistochemical characteristics of the lesion were examined. Results: The clinical symptoms of 7 children included nasal congestion, runny nose, open mouth breathing, snoring during sleep, difficulty feeding, and strabismus. All patients underwent electronic nasopharyngoscopy examination, with 5 cases of tumors located in the right nasal cavity and 2 cases in the left nasal cavity. No case of bilateral nasal cavity disease was found. All 7 patients underwent complete imaging examinations, with 5 patients underwent MRI and CT examinations, 1 patient underwent CT examination only, and 1 patient underwent MRI examination only. The CT results showed that all tumors were broad-based, with uneven density, multiple calcifications and bone remodeling, and some exhibited multiple cystic components. The MRI results showed that the tumor showed low signal on T1 weighted imaging and high or slightly high signal on T2 weighted imaging. All patients were diagnosed through histopathological examination and immunohistochemistry, including 7 cases of Ki-67 and SMA (+), 5 cases of S-100 and Vimentin (+), and all EMA and GFAP were negative. All patients underwent endoscopic resection surgery through the nasal approach, with 3 cases using navigation technology. Five cases of tumors were completely removed, and two cases of tumors were mostly removed. No nasal packing was performed after surgery, and no postoperative nasal, ocular, or intracranial complication occurred in all patients. Follow up assessments conducted 6 to 84 months post-surgery revealed no instances of tumor recurrence in any of the patients. Conclusions: The clinical symptoms of children with NCHM mainly depend on the size and location of the tumor. Nasal endoscopic surgery is the main treatment method. In cases where critical structures like the skull base or orbit are implicated, staged surgical interventions may be warranted. Long-term follow-up is strongly advised to monitor for any potential recurrence or complications.

Pth1r in Neural Crest Cells Regulates Nasal Cartilage Differentiation.

Neural crest cells (NCC) arise from the dorsal margin of the neural plate border and comprise a unique cell population that migrates to and creates the craniofacial region. Although factors including Shh, Fgf8, and bone morphogenetic proteins have been shown to regulate these biological events, the role of parathyroid hormone 1 receptor (Pth1r) has been less studied. We generated an NCC-specific mouse model for Pth1r and researched gene expression, function, and interaction focusing on nasal cartilage framework and midfacial development. Wnt1-Cre;Pth1rfl/fl;Tomatofl/+ mice had perinatal lethality, but we observed short snout and jaws, tongue protrusion, reduced NCC-derived cranial length, increased mineralization in nasal septum and hyoid bones, and less bone mineralization at interfrontal suture in mutants at E18.5. Importantly, the mutant nasal septum and turbinate cartilage histologically revealed gradual, premature accelerated hypertrophic differentiation. We then studied the underlying molecular mechanisms by performing RNA seq analysis and unexpectedly found that expression of Ihh and related signaling molecules was enhanced in mutant nasomaxillary tissues. To see if Pth1r and Ihh signaling are associated, we generated a Wnt1-Cre; Ihhfl/fl;Pth1rfl/fl;Tomatofl/+ (DKO) mouse and compared the phenotypes to those of each single knockout mouse: Wnt1-Cre; Ihhfl/fl;Pth1rfl/+;Tomatofl/+ (Ihh-CKO) and Wnt1-Cre;Ihhfl/+;Pth1rfl/fl;Tomatofl/+ (Pth1r-CKO). Ihh-CKO mice displayed a milder effect. Of note, the excessive hypertrophic conversion of the nasal cartilage framework observed in Pth1r-CKO was somewhat rescued DKO embryos. Further, a half cAMP responsive element and the 4 similar sequences containing 2 mismatches were identified from the promoter to the first intron in Ihh gene. Gli1-CreERT2;Pth1rfl/fl;Tomatofl/+, a Pth1r-deficient model targeted in hedgehog responsive cells, demonstrated the enlarged hypertrophic layer and significantly more Tomato-positive chondrocytes accumulated in the nasal septum and ethmoidal endochondral ossification. Collectively, the data suggest a relevant Pth1r/Ihh interaction. Our findings obtained from novel mouse models for Pth1r signaling illuminate previously unknown aspects in craniofacial biology and development.

[Effectiveness of comprehensive rhinoplasty on secondary nasal deformity with saddle nasal deformity after cleft lip surgery].

Objective: To investigate the effectiveness of comprehensive rhinoplasty with autogenous costal cartilage grafting and prosthesis augmentation rhinoplasty in the treatment of secondary nasal deformity with saddle nasal deformity after cleft lip surgery. Methods: The clinical data of 96 patients with secondary nasal deformity with saddle nasal deformity after cleft lip surgery between September 2008 and January 2019 were retrospectively analyzed. There were 17 males and 79 females with an average age of 25.6 years (range, 17-38 years). Autogenous costal cartilage grafts were used to construct stable nasal tip framework and enhance the strength of alar cartilage. Nasal dorsum prostheses (39 cases of bulge, 45 cases of silicone prosthesis) or autogenous costal cartilage (12 cases) were used for comprehensive rhinoplasty. Visual analogue scale (VAS) score was used to evaluate the postoperative satisfaction subjectively, and nasal alar height symmetry index, nasal alar width symmetry index, nasal dorsum central axis deviation angle, and nasal columella deviation angle were calculated to evaluate objectively before and after operation. Results: All patients were followed up 6 months to 8 years, with an average of 13.4 months. Nasal septal hematoma occurred in 3 patients after operation, which was improved after local aspiration and nasal pressure packing. Two cases had mild deformation of the rib cartilage graft of the nasal dorsum, one of which had no obvious deviation of the nasal dorsum and was not given special treatment, and one case underwent the cartilage graft of the nasal dorsum removed and replaced with silicone prosthesis. The incisions of the other patients healed by first intention, and there was no complication such as postoperative infection and prosthesis displacement. The nasal alar height symmetry index, nasal alar width symmetry index, nasal dorsum central axis deviation angle, and nasal columella deviation angle significantly improved after operation when compared with preoperative ones ( P<0.05). Postoperative subjective satisfaction evaluation reached the level of basic satisfaction or above, and most of them were very satisfied. Conclusion: Comprehensive rhinoplasty using autologous rib cartilage grafting to construct a stable nasal tip support, combined with dorsal nasal prosthesis or autologous cartilage implantation, can achieve good effectiveness on secondary nasal deformity with saddle nasal deformity after cleft lip surgery.

Patient Outcomes in Lateral Crural Repositioning and Reconstruction in Revision Rhinoplasty.

Background: In revision rhinoplasty, lateral crural repositioning/reconstruction is considered a complex maneuver. The aim of this study is to measure patient outcomes after lateral crural repositioning/reconstruction in revision rhinoplasty. Methods: In this retrospective case series, patients who underwent revision rhinoplasty with lateral crural repositioning/reconstruction for functional, cosmetic, or combined purposes were reviewed. Preoperative Standardized Cosmesis and Health Nasal Outcomes Survey (SCHNOS) scores, functional and cosmetic visual analog scales (VAS-functional [F] and VAS-cosmetic [C]), and lateral wall insufficiency (LWI) grades were compared with their respective postoperative scores. Results: Forty-two patients were identified who underwent lateral crural repositioning. The mean postoperative follow-up for ≤6 months (PO1) and >6 months (PO2) was 3.1 (standard deviation [SD] 1.7) and 11.5 (SD 5.3) months, respectively. At both postoperative periods, significant improvement (p < 0.05) in patient-reported outcomes was observed in mean SCHNOS-Obstruction, SCHNOS-Cosmesis, VAS-F, and VAS-C scores. The postoperative changes in LWI scores (Δ) were significant on both sides at zone 1 at PO1 (p < 0.05) and PO2 (p < 0.05), and at PO2 on the left side (p < 0.05) only, for zone 2. Conclusion: Lateral crural repositioning with reconstruction is an effective maneuver in revision rhinoplasty in a subset of patients and specifically helps to improve nasal tip aesthetics while preserving function.

Effect of Locally Administered Estradiol on Wound Healing in a Nasal Septal Perforation Animal Model.

We aimed to investigate the effect of estradiol on wound healing in an experimental nasal septal perforation (NSP) model created in rats. Twenty-two Sprague Dawley healthy male rats were separated into two groups. NSP, approximately 2 mm in diameter, was created in each animal. The 0.1 mL 0.12% estradiol (12 g/L) (study group) and 0.1 mL 0.9% saline (9 g/L) (control group) were applied topically once a day for 14 days. The rats were sacrificed on the 14th day and the cartilage nasal septum of each animal was excised for histopathological examination. The nasal mucosal epithelial regeneration and degeneration, acute inflammatory cell count, fibroblast number, vascularization, granulation tissue formation, giant cell number, eosinophil number, degeneration and regeneration of the nasal cartilage, and collagen density were examined. The macroscopic closure rate of the perforations and histopathological parameters were evaluated statistically. In this study, the epithelial regeneration, the fibroblast count, the granulation tissue formation, and the amount of collagen were significantly higher in the study group than in the saline group (p < 0.05). The acute inflammatory activity was lower in the estradiol group than in the saline group (p < 0.05). There was no statistically significant difference in the closure rate of perforation between the two groups (p = 0.163). No significant difference was found in other comparisons (p > 0.05). The locally administered estradiol may improve wound healing of the nasal septum in an experimental NSP animal model. LEVEL OF EVIDENCE: Not applicable.

Structural Approach to Secondary Repair of the Unilateral Cleft Lip Nasal Deformity.

SUMMARY: Management of the unilateral cleft lip nasal deformity is complex because of the underlying significant asymmetry of the lower lateral cartilages and soft tissues of the nasal base. Suturing and grafting techniques may leave the patient with residual asymmetries of the nasal tip and nostrils. Some of this residual asymmetry may be attributable in part to the anchoring effect of the vestibular skin attachments to the lower lateral cartilages. This article discusses the use of lateral crural release, repositioning, and support with lateral crural strut grafts to manage the nasal tip. The technique involves freeing the vestibular skin from the undersurface of the lateral crura and domes and placement of lateral crural strut grafts with or without amputation of the ipsilateral dome and lateral crura to allow precise resuturing to the caudal septal extension graft. This technique is coupled with the use of a caudal septal extension graft to stabilize the nasal base and provide a strong foundation for the repair. Treatment of the nasal base may require skeletal augmentation to aid in creating symmetry of the alar insertions. Costal cartilage is needed in most cases to provide adequate structural support. Nuances in technique are discussed to help maximize outcomes.

Age-Related Histologic and Biochemical Changes in Auricular and Nasal Cartilages.

OBJECTIVE: Analyze age-related changes in histologic features and biochemical properties of human auricular cartilage and two subsites of nasal cartilages (quadrangular cartilage and dorsal septal articulation with upper lateral cartilages). STUDY DESIGN: Prospective cross-sectional study of nasal and auricular cartilages from seventy-three (73) live donors. METHODS: Auricular cartilage (AC), quadrangular cartilage (QC), and dorsal septal cartilage articulation (DSA) with the upper lateral cartilage (ULCs) were collected intraoperatively. Histochemical staining was used: Safranin O for glycosaminoglycans (GAGs), Verhoeff's for elastin, and Masson's trichrome for collagen. ImageJ2 software was used to calculate cell count and percent stained for each cartilage type. R studio "ggplot" package was used to visualize age versus cell count or percent stained. RESULTS: Participant ages ranged from 20 to 77 years, average 46.5 years. There was a significant decline in GAGs with age for the DSA subsite, (n = 64, p < 0.001). Significant increase in collagen content with age was observed for DSA subsite (n = 66, p < 0.001) and the QC subsite (n = 64, p < 0.05). There was a statistically insignificant decline in elastin with age (n = 41, p = 0.309) for AC. Cell count declined with age at all cartilage subsites. CONCLUSION: Our findings confirm that there were age-related decreases in cartilage glycosaminoglycan content, and chondrocyte cell count in both auricular and nasal cartilages. We have also confirmed that collagen content increases with age for both auricular and nasal cartilage. The histologic findings while not statistically significant in all comparisons, provides additional evidence that there is some loss of structural integrity and flexibility in nasal and auricular cartilage with aging. LEVEL OF EVIDENCE: NA Laryngoscope, 134:1220-1226, 2024.

Cog graft, a new septal extension graft for designing nasal tip rotation and projection in rhinoplasty.

BACKGROUND: Adjusting the nasal tip rotation and tip projection according to the patient's face and wishes is a very important stage in rhinoplasty with the use of a cog graft positioning the tip point in the appropriate place is possible by adjusting the nose length, tip projection and tip rotation together. OBJECTIVE: The aim of this study is to facilitate positioning the tip rotation and projection in the appropriate place according to the patient's needs in rhinoplasty with Cog graft. MATERIALS AND METHODS: Cog graft was applied in 32 patients who underwent rhinoplasty. Cog graft was prepared from costal cartilage in 10 patients and from septal cartilage in 22 patients. Cog graft was prepared by shaping the superior edge of the septal extension graft like a gear wheel. It is fixed to provide desired projection to the caudal septum. In the position where rotation and projection are evaluated adequately, the graft is fixed with sutures. They were followed in average 18 months (between 6 and 24 months). RESULTS: Twenty of the patients were primary cases and 12 were revision cases. The targeted rotation and projection results were achieved in all patients. All patients had satisfactory esthetic results. CONCLUSIONS: Cog graft is a useful graft with which we can adjust the nose length, projection and rotation appropriately and in a short time with a single graft.

Crossing fibers may underlie the dynamic pulling forces of muscles that attach to cartilage at the tip of the nose.

The present study used microdissection, histology, and microcomputed tomography (micro-CT) with the aims of determining the prevalence and patterns of the depressor septi nasi (DSN) and orbicularis oris (OOr) muscles attached to the footplate of the medial crus (fMC) of the major alar cartilage, focusing on their crossing fibers. The DSN and OOr attached to the fMC of the major alar cartilage were investigated in 76 samples from 38 embalmed Korean adult cadavers (20 males, 18 females; mean age 70 years). The DSN, OOr, or both were attached to the fMC. When the DSN ran unilaterally or was absent, some OOr fibers ascended to attach to the fMC instead of the DSN in 20.6% of the samples. Crossing fibers of the DSN or OOr attached to the fMC were found in 82.4% of the samples. Bilateral and unilateral crossing fibers were found in 32.4% and 50.0%, respectively, and no crossing fibers were found in 17.6%. The DSN and OOr that attached to the fMC could be categorized into six types according to presence of the DSN and the crossing patterns of the DSN and OOr. Anatomical findings of the DSN and OOr that attached to the fMC were confirmed in histology and micro-CT images. These findings offer insights on anatomical mechanisms that may underlie the dynamic pulling forces generated by muscles that attach to the fMCs and on evolutionary variation observed in human facial expressions. They can also provide useful information for guiding rhinoplasty of the nasal tip.

Are preservation rhinoplasty techniques safer than structural ones?

This narrative review paper evaluates the preservation rhinoplasty (PR) technique in all aspects. The literature survey was performed in PubMed, EBSCO, UpToDate, and Proquest Central databases of Kirikkale University, Google and Google Scholar databases. The advent of the preservation rhinoplasty (PR) approach has led to a radical shift in the mindset surrounding rhinoplasty procedures. K-area (keystone region) loss, lateral cartilage collapse, and nasal stenosis are all avoidable with preservation measures. The nasal bones, the superior lateral cartilage, the quadrilateral cartilage, and the perpendicular blade of the ethmoid meet at the point known as Zone K. The variety of problems that might develop due to carelessness in this area demonstrates the significance of maintaining the nose's stability and structure. The three components of a preservation rhinoplasty (PR) procedure are (1) preserving the scroll ligament complex by elevating the soft tissue envelope (STE) in a subperichondrial-subperiosteal plane, (2) preserving the nasal dorsum without creating an open roof deformity, and (3) preserving the alar cartilages and achieving the desired shape using sutures rather than excision. Dorsal preservation is one of the three components that make up PR. However, the two concepts are not synonymous. PR involves elevating a skin sleeve from the subperichondrial-subperiosteal plane, preserving the osteocartilaginous dorsum, maintaining the alar cartilages with minor excision and using sutures to achieve the desired form.

Caudal septal extension grafts: conchal cartilage or PDS foil-empowered nasal cartilage.

We reviewed the potential benefits of conchal cartilage or Polydioxanone (PDS) foil-empowered nasal cartilage as caudal septal extension grafts (CSEGs). Research methods included searching online databases such as Google, Google Scholar, PubMed, and Proquest Central at Kirikkale University. Use terms like "caudal septal extension grafts," "septal extension grafts," "conchal cartilage," and "PDS foil-empowered nasal cartilage" to find related articles. Due to the anchoring of the lower alar cartilage to the nasal septum, the results of a CSEG rhinoplasty are relatively stable over the long term. They can be adjusted independently by the rhinoplasty surgeon. Over time, the skin and soft tissue envelope contract and a downward force for these grafts develops. It allows for independent regulation of projection and rotation, unlike conventional columellar strut procedures and lateral crural steal techniques. Inadequate cartilage may need conchal or costal cartilage, depending on the application and the need for projection and counter rotation. Costal cartilage transplant outperformed conchal cartilage graft in a rabbit model regarding tip projection and angle relapse rate. Three-patient case series show that PDS foil-enhanced nasal cartilage led to septal cartilage loss. However, other research draws a different result, finding that PDS foil-enhanced nasal cartilage prevented growth inhibition in the developing nasal septum following septoplasty, and reduced late problems in animals. The caudal septal extension grafts should prioritize septum cartilage if it is readily available, of adequate size, and with sufficient strength. If this is not possible, PDS foil-enhanced nasal cartilage fragments or conchal cartilage could be used as a backup. PDS foil will maintain the integrity and stability of the implanted cartilage. Due to its strength, stability, and convenient location, conchal cartilage will serve as the second donor site.

Salmon nasal cartilage proteoglycan stimulates hair growth.

Hair loss is a commonly encountered problem. In this study, hair growth was enhanced by daily oral ingestion of salmon nasal cartilage proteoglycan (PG) in mice. Proteoglycan stimulated vesicular endothelial growth factor production in human follicle dermal papilla cells through insulin growth factor-1 receptor signaling, suggesting the possibility of hair loss improvement by PG ingestion.

A novel surgical approach for feline stenotic nares: Bilateral wedge resection of the dorsal lateral nasal cartilage in seven cases.

OBJECTIVE: Surgical correction of stenotic nares, one component of brachycephalic obstructive airway syndrome (BOAS), is not referenced as often in cats as it is in dogs. Similar to dogs, stenotic nares emerge as a significant contributor in the development of BOAS in cats. In this study, we propose that stenotic nares in brachycephalic cats arise from an elongated dorsal lateral nasal cartilage. The aim of this paper is to illustrate a novel surgical technique to alleviate stenosis-associated clinical signs by performing full-thickness bilateral wedge resection of the excessive cartilage. ANIMALS: Seven cats that underwent rhinoplasty with full-thickness bilateral wedge resection along the dorsal lateral nasal cartilage between 2019 and 2022 at Pan-Asia Veterinary Clinic in Taipei, Taiwan. METHODS: Clinical data of all cats included in the study were retrospectively reviewed. Surgical procedures were recorded. A full-thickness bilateral wedge resection was made along the dorsal lateral nasal cartilage adjacent to the non-hairy area. The full-thickness wedge resection was then apposed and closed, resulting in the abduction of the wing of the nostrils. Postoperative outcomes were evaluated according to follow-up sessions by the authors, and an owner survey was conducted at least 6 months post-surgery. RESULTS: All cats included in this study had a favourable outcome with no complications reported following surgery. The degree of nostril stenosis was improved, and relapse of clinical signs was not reported. Overall, the quality of life of cats that underwent rhinoplasty was significantly improved. CLINICAL RELEVANCE: The results support that the innovative procedure described in this study is highly promising and holds great potential in restoring quality of life and halting disease progression of cats with BOAS.

[Study on the influence of buried thread nasal augmentation on dorsal soft tissue of nose and revision rhinoplasty].

Objective: To investigate the influence of buried thread nasal augmentation on dorsal soft tissue of nose and revision rhinoplasty. Methods: A clinical data of 29 patients requesting revision rhinoplasty after buried thread nasal augmentation, who were admitted between July 2017 and July 2019 and met the selection criteria, was retrospectively analyzed. All patients were female with an average age of 26.8 years (range, 18-43 years). The patiens were admitted to the hospital at 3-48 months after buried thread nasal augmentation (median, 15 months). Among them, there were 18 cases of insufficient nasal tip projection, 22 cases of insufficient nasal root projection, 7 cases of threads ectasia, 5 cases of threads exposure, 3 cases of infection, and 10 cases with two or more conditions. There were 9 cases of combined short nose deformity, 1 case of spherical hypertrophy of the nasal tip, 3 cases of deviation of the nasal columella, 3 cases of excessive width of the nasal base, and 1 case of nasal hump. Three infected patients only underwent threads removal and debridement. The rest patients underwent revision rhinoplasty, and the dorsum of the nose was made with polytetrafluoroethylene expansion; the tip of the nose was reshaped by taking autologous rib cartilage and alar cartilage in 16 cases, and by taking autologous septal cartilage and alar cartilage in another 10 cases. The threads and surrounding tissue specimens removed during operation were subjected to histologic observation. Nasal length and nasal tip projection were measured after revision rhinoplasty and the ratio was calculated to evaluate the nasal morphology; patient satisfaction was evaluated using the Likert 5-grade scale. Results: Patients were followed up 12-48 months (mean, 18 months). Inflammation was controlled in 3 patients with infections caused by buried thread nasal augmentation. The remaining 26 patients had satisfactory results immediately after revision rhinoplasty. Before revision rhinoplasty and at 7 days and 6 months after revision rhinoplasty, the nasal length was (4.11±0.34), (4.36±0.25), and (4.33±0.22) cm, respectively; the nasal tip projection was (2.34±0.25), (2.81±0.18), and (2.76±0.15) cm, respectively; and the nasal tip projection/nasal length ratio was 0.57±0.08, 0.65±0.05, and 0.64±0.04, respectively. There were significant differences in the nasal length and the nasal tip projection between time points ( P<0.05). There was a significant difference in the nasal tip projection/nasal length ratio between pre- and post-operation ( P<0.05), but there was no significant difference between 7 days and 6 months after operation ( P>0.05). The Likert score for satisfaction ranged from 1.5 to 5.0 (mean, 4.05). During follow-up period of 26 patients, no nasal prosthesis was exposed, and the shape of the nose was stable, and the nasal skin of 5 patients with exposed threads could be seen with different degrees of scarring; there was no infection, cartilage resorption, and no cartilage deformation, displacement, or exposure. Histological observation showed that absorbable threads were not only absorbed after implantation, but also with the prolongation of time, the inflammatory changes in the surrounding tissues caused by decomposition and absorption of the threads showed a gradual aggravation of the first, the heaviest inflammatory reaction in 6 to 12 months, and then gradually reduce the trend. Conclusion: After implantation of the absorbable thread into the subcutaneous tissue of the nasal dorsum, the nature of the thread is different from the body's own tissue, which will affect the soft tissue compliance of the nasal dorsum. The degradation and absorption of the thread will stimulate the infiltration of inflammatory cells and the proliferation of fibroblasts in the surrounding tissue and then form scar tissue, which will affect the design and effect of revision rhinoplasty.

Enhanced BMP signaling leads to enlarged nasal cartilage formation in mice.

Bone morphogenetic proteins (BMPs) are required for craniofacial bone development. However, it remains elusive how BMP signaling regulates craniofacial cartilage development. To address this question, we utilized a genetic system to enhance BMP signaling via one of BMP type I receptors ALK2 in a chondrocyte-specific manner (hereafter Ca-Alk2:Col2-Cre) in mice. Ca-Alk2:Col2-Cre mice died shortly after birth due to severe craniofacial abnormalities including cleft palate, defective tongue, and shorter mandible formation. Histological analysis revealed that these phenotypes were attributed to the extensive chondrogenesis. Compared with controls, enhanced SOX9 and RUNX2 production were observed in nasal cartilage of Ca-Alk2:Col2-Cre mice. To reveal the mechanisms responsible for enlarged nasal cartilage, we examined Smad-dependent and Smad-independent BMP signaling pathways. While the Smad-independent BMP signaling pathway including p38, ERK, and JNK remained silent, the Smad1/5/9 was highly phosphorylated in Ca-Alk2:Col2-Cre mice. Interestingly, Ca-Alk2:Col2-Cre mice showed enhanced S6 kinase phosphorylation, a readout of mammalian target of rapamycin complex 1 (mTORC1). These findings may suggest that enhanced Smad-dependent BMP signaling positively regulates the mTOR pathway and stimulates chondrocytes toward hypertrophic differentiation, thereby leading to enlarged nasal cartilage formation in mice.

An Innovative Stent Consisting of Expanded Polytetrafluoroethylene and Ear Cartilage in Rhinoplasty For Asians: Application I of Dai's Exogenous Extension Stent Concept.

BACKGROUND: Restricted ventilation is common after rhinoplasty with an endogenous extension stent. The authors proposed an exogenous extension stent concept for Asian rhinoplasty patients to avoid this problem. Herein, we introduce an innovative stent in rhinoplasty for Asians, which is an application of this concept. METHODS: An L-shaped expanded polytetrafluoroethylene is hand-carved, and the long arm is placed at the nose back to improve the flatness of the nose, while the short arm supports the nasal column to raise the nose tip. The prosthesis does not occupy nasal volume and therefore theoretically does not affect nasal ventilation. The fan-shaped ear cartilage was placed at the nasal tip to prevent visualization of the nasal tip. The safety and effectiveness of this method were verified through 20 years of clinical practice. The difficulty of learning and popularizing the method was tested through the course of rhinoplasty among 22 plastic surgeons. RESULTS: After 20 years of clinical practice, it was found that this stent could not only effectively improve the nasal dorsum and tip morphology, but also did not actually affect the nasal volume and thus did not affect the nasal ventilation of patients. Among the trainees in plastic surgery, we found that it was not difficult to learn this method of rhinoplasty and the trainees could complete the prosthesis carving well after standardized training. CONCLUSION: This stent consisting of expanded polytetrafluoroethylene and ear cartilage is suitable in rhinoplasty for Asians with significant advantages, one of which is that it has no risk of resulting in restricted nasal ventilation. LEVEL OF EVIDENCE: Level IV.

Human nasal cartilage: Functional properties and structure-function relationships for the development of tissue engineering design criteria.

Nose reconstruction often requires scarce cartilage grafts. Nasal cartilage properties must be determined to serve as design criteria for engineering grafts. Thus, mechanical and biochemical properties were obtained in multiple locations of human nasal septum, upper lateral cartilage (ULC), and lower lateral cartilage (LLC). Within each region, no statistical differences among locations were detected, but anisotropy at some septum locations was noted. In the LLC, the tensile modulus and ultimate tensile strength (UTS) in the inferior-superior direction were statistically greater than in the anterior-posterior direction. Cartilage from all regions exhibited hyperelasticity in tension, but regions varied in degree of hyalinicity (i.e., Col II:Col I ratio). The septum contained the most collagen II and least collagen I and III, making it more hyaline than the ULC and LLC. The septum had a greater aggregate modulus, UTS, and lower total collagen/wet weight (Col/WW) than the ULC and LLC. The ULC had greater tensile modulus, DNA/WW, and lower glycosaminoglycan/WW than the septum and LLC. The ULC had a greater pyridinoline/Col than the septum. Histological staining suggested the presence of chondrons in all regions. In the ULC and LLC, tensile modulus correlated with total collagen content, while aggregate modulus correlated with pyridinoline content and weakly with pentosidine content. However, future studies should be performed to validate these proposed structure-function relationships. This study of human nasal cartilage provides 1) crucial design criteria for nasal cartilage tissue engineering efforts, 2) quantification of major and minor collagen subtypes and crosslinks, and 3) structure-function relationships. Surprisingly, the large mechanical properties found, particularly in the septum, suggests that nasal cartilage may experience higher-than-expected mechanical loads. STATEMENT OF SIGNIFICANCE: While tissue engineering holds promise to generate much-needed cartilage grafts for nasal reconstruction, little is known about nasal cartilage from an engineering perspective. In this study, the mechanical and biochemical properties of the septum, upper lateral cartilage (ULC), and lower lateral cartilage (LLC) were evaluated using cartilage-specific methods. For the first time in this tissue, all major and minor collagens and collagen crosslinks were measured, demonstrating that the septum was more hyaline than the ULC and LLC. Additionally, new structure-function relationships in the ULC and LLC were identified. This study greatly expands upon the quantitative understanding of human nasal cartilage and provides crucial engineering design criteria for much-needed nasal cartilage tissue engineering efforts.