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1.
Lüerssen K  Lubatschowski H  Ptok M 《HNO》2007,55(6):443-446
The application of lasers in microsurgery of the vocal fold has very special requirements. Easy handling as well as a precise cutting quality with a small laser induced thermal necrosis zone are necessary. In this study, an Erbium:YAG laser was evaluated for phonosurgery. For this, vocal folds from the porcine larynx were irradiated with the Erbium laser wavelength of 3 mum. The ablation rate, as well as the mechanical and thermal damage were investigated as a function of pulse duration, repetition rate and laser fluence. The results show that Erbium lasers are well suited for application on the vocal fold. The laser induced thermal damage was restricted to a superficial layer of only about 20-30 microm, resulting in a loss of the multilayered epithelium. Thermal necrosis had a range of about 5 microm. Further investigations on the vocal folds of humans must be performed to determine whether this laser is qualified for clinical applications.  相似文献   

2.
Kimura M  Tayama N  Chan RW 《The Laryngoscope》2003,113(4):607-613
OBJECTIVES/HYPOTHESIS: Many existing studies of vocal fold geometry are based on anatomical measurements made on histologically fixed laryngeal tissues using formalin. However, the validity of these geometric data is questionable because of the potentially significant tissue deformation associated with formalin fixation, particularly tissue shrinkage. Previous experiments have shown that valid geometric data may be obtained on vocal fold tissue samples quickly frozen with liquid nitrogen. Based on this finding, the present study attempted to quantify the geometric deformation of formalin-fixed vocal fold tissues with respect to quick-frozen tissues. METHODS: Six freshly harvested canine larynges were quickly frozen with liquid nitrogen and sectioned at the mid-membranous coronal plane. Each larynx was thawed and divided into halves along the midsagittal plane, one of which was not fixed; the other was fixed with formalin, from which histological tissue sections were also prepared. Measurements of vocal fold geometry were made on digital images of mid-membranous coronal sections of the tissue samples, based on linear dimensions of vocal fold depth and thickness defined functionally for biomechanical applications. RESULTS: Significant shrinkage of the vocal fold (particularly the vocal fold body) and considerable distortion of the vocal fold contour (particularly at the free edge) were observed for the formalin-fixed samples and the histological sections in comparison with the unfixed samples. CONCLUSIONS: Results of the present study suggested that significant geometric artifacts are induced by conventional histological fixation of laryngeal tissues using formalin. These artifacts should be carefully considered for interpreting any vocal fold geometric data obtained through formalin fixation.  相似文献   

3.
目的 探讨支撑喉镜下应用CO2激光分离切除声带蹼样粘连后置入硅胶膜治疗继发性声带粘连的临床疗效.方法 以21例继发性声带粘连的成年患者为研究对象,其中,发生于双侧声带任克水肿、声带小结、声带息肉、声带白斑手术后16例,喉乳头状瘤手术后4例,喉部外伤导致声带粘连1例,粘连范围均为声带前1/3~1/2;均在支撑喉镜下应用CO2激光分离并切除声带前部正中粘连带后,置入的硅胶膜使其隔离声门前端分离的创面并经喉内、外联合进路缝合固定于颈前皮肤;术后3周取出硅胶膜,随访半年,观察疗效.结果 20例患者术后3周顺利取出硅胶膜,1例患者术后2周因颈部软组织感染取出硅胶膜后痊愈;术后随访6个月,除1例患者再次发生声带前联合粘连外,其余20例患者声带前联合均获得良好三角形形态,无瘢痕及肉芽形成,声嘶均明显改善.结论 支撑喉镜下CO2激光分离联合硅胶膜置人隔离创面3周治疗声带粘连,创伤小,效果好,并发症少.  相似文献   

4.
Laryngeal papillomas represent a disease of the head and neck that can be treated only symptomatically by surgical means. Twelve Patients (six adults and six children) with recurrent laryngeal papillomas were admitted to a pilot study for photodynamic laser treatment (Fig. 2). Forty-eight hours after intravenous application of hematoporphyrin derivative, PDT was performed by means of a specially developed laser light applicator (Fig. 1) under general anaesthesia. The laser light was generated by an argon-pumped dye laser system operating at a wavelength of 630 nm. On endoscopic evaluation the papilloma showed a whitish livid colour 24 hours after PDT. During the following 3-5 days the papilloma tissue was sloughed and the true and false vocal cords were covered by fibrin. Some 3-4 weeks after PDT the endolaryngeal mucosa had reepithelized in all patients with no signs of residual disease (Fig. 3). Despite the initial multifocal nature of the papilloma, even beyond the anterior commissure, no synechia developed.  相似文献   

5.
Quantification of the elastic properties of the human vocal fold provides invaluable data for researchers deriving mathematical models of phonation, developing tissue engineering therapies, and as normative data for comparison between healthy and scarred tissue. This study measured the shear modulus of excised cadaver vocal folds from 20 subjects. Twenty freshly excised human larynxes were evaluated less than four days post-mortem. They were split along the saggital plane and mounted without tension. Shear modulus was obtained by two different methods. For method 1 cyclical shear stress was applied transversely to the mid-membranous portion of the vocal fold, and shear modulus derived by applying a simple shear model. For method 2 the apparatus was configured as an indentometer, and shear modulus obtained from the stress/strain data by applying an established analytical technique. Method 1 shear model for male larynxes yielded a range from 246 to 3,356 Pa, with a mean value of 1,008 and SD of 380. The range for female larynxes was 286–3,332 Pa, with a mean value of 1,237 and SD of 768. Method 2 indentometer model for male larynxes yielded a range from 552 to 2,741 Pa, with a mean value of 1,000 and SD of 460. The range for female larynxes was 509–1,989 Pa, with a mean value of 1,332 and SD of 428. We have successfully demonstrated two methodologies that are capable of directly measuring the shear modulus of the human vocal fold, without dissecting out the vocal fold cover tissue. The sample size of nine female and 11 male larynxes is too small to validate a general conclusion. The high degree of variability in this small cohort of subjects indicates that factors such as age, health status, and post-mortem delay may be significant; and that there is range of ‘normality’ for vocal fold tissue. This project received financial support from the Engineering Physics and Science Research Council of Great Britain (EPSRC) and the Eugene B Casey Foundation (JBK).  相似文献   

6.
The ability to measure the biomechanical properties of the vocal fold in vivo is both an aid to diagnosis and enhances our knowledge of how the vocal folds operate. This paper details a new instrument that is capable of taking readings of the spring rate of the vocal fold in a repeatable manner. We also present three sets of readings taken from two volunteer patients. Patient 1 was suffering from polyp growth, and the data presented are taken from both the damaged vocal fold and the healthy vocal fold. The third set of readings was obtained from a similar volunteer and taken from a healthy vocal fold. It can be seen that the data obtained from the healthy vocal folds are similar and that the data obtained from the diseased vocal fold is at variance.  相似文献   

7.
Characterization of vocal fold scarring in a canine model   总被引:9,自引:0,他引:9  
OBJECTIVE: The objective was to assess the histological and viscoelastic shear tissue properties of the scarred vocal fold lamina propria at 2 and 6 months postoperatively in a canine model. STUDY DESIGN: Experimental, nonrandomized prospective study. METHODS: Six canine larynges were injured using a vocal fold stripping procedure. At 2 and 6 months postoperatively, histological analyses of the scarred and control lamina propria samples were completed for collagen, procollagen, elastin, and hyaluronic acid. RESULTS: In canines killed at 2 months, scarred tissue samples contained increased procollagen and decreased elastin. Elastin fibers in the scarred lamina propria were characteristically tangled and disorganized. In canines killed at 6 months, scarred tissue samples showed decreased elastin and increased collagen. Collagen fibers formed thick, disorganized bundles, and elastin fibers were disorganized throughout the entire scarred vocal fold lamina propria. Viscoelastic shear tissue measurements revealed increased stiffness and viscosity in one of three cases at 2 months and in all three cases at 6 months, indicating increased stiffness and resistance to shear flow during oscillatory shear deformation for scarred tissue samples. No differences were observed between the two postoperative times. CONCLUSIONS: Results indicated that viscoelastic tissue changes may take place before scar maturation in the scarred vocal fold lamina propria and that, although abundant collagen deposition may influence viscoelastic shear tissue properties, disorganization of collagen and elastin fibers, thick bundle collagen formation, or the interplay of several of these factors might also play a contributing role.  相似文献   

8.
OBJECTIVES: A prospective, controlled animal study was performed to determine whether the use of injectable, chemically modified hyaluronic acid (HA) derivatives at the time of intentional vocal fold resection might facilitate wound repair and preserve the unique viscoelastic properties of the vocal fold extracellular matrix. METHODS: We performed bilateral vocal fold biopsies on 33 rabbits. Two groups of rabbits were unilaterally treated with 2 different HA derivatives--Carbylan-SX and HA-DTPH-PEGDA--at the time of resection. Saline was injected as a control into the contralateral fold. The animals were painlessly sacrificed 3 weeks after biopsy and injection. The outcomes measured included histologic fibrosis level, tissue HA level, and tissue viscosity and elasticity. RESULTS: The Carbylan-SX-treated vocal folds were found to have significantly less fibrosis than the saline-treated controls. The levels of HA in the treated vocal folds were not significantly different from those in the controls at 3 weeks as measured by enzyme-linked immunosorbent assay. The Carbylan-SX-treated vocal folds had significantly improved biomechanical properties of elasticity and viscosity. The HA-DTPH-PEGDA injections yielded significantly improved viscosity, but not elasticity. CONCLUSIONS: Prophylactic in vivo manipulation of the extracellular matrix with an injectable Carbylan-SX hydrogel appears to induce vocal fold tissue regeneration to yield optimal tissue composition and biomechanical properties favorable for phonation.  相似文献   

9.
Viscoelasticity of rabbit vocal folds after injection augmentation   总被引:3,自引:0,他引:3  
OBJECTIVES/HYPOTHESIS: Vocal fold function is related to the viscoelasticity of the vocal fold tissue. Augmentation substances used for injection treatment of voice insufficiency may alter the viscoelastic properties of vocal folds and their vibratory capacity. The objective was to compare the mechanical properties (viscoelasticity) of various injectable substances and the viscoelasticity of rabbit vocal folds, 6 months after injection with one of these substances. STUDY DESIGN: Animal model. METHODS: Cross-linked collagen (Zyplast), double cross-linked hyaluronan (hylan B gel), dextranomers in hyaluronan (DHIA), and polytetrafluoroethylene (Teflon) were injected into rabbit vocal folds. Six months after the injection, the animals were killed and the right- and left-side vocal folds were removed. Dynamic viscosity of the injected substances and the vocal folds was measured with a Bohlin parallel-plate rheometer during small-amplitude oscillation. RESULTS: All injected vocal folds showed a decreasing dynamic viscosity with increasing frequency. Hylan B gel and DiHA showed the lowest dynamic viscosity values, and vocal folds injected with these substances also showed the lowest dynamic viscosity (similar to noninjected control samples). Teflon (and vocal folds injected with Teflon) showed the highest dynamic viscosity values, followed by the collagen samples. CONCLUSION: Substances with low viscoelasticity alter the mechanical properties of the vocal fold to a lesser degree than substances with a high viscoelasticity. The data indicated that hylan B gel and DiHA render the most natural viscoelastic properties to the vocal folds. These substances seem to be appropriate for preserving or restoring the vibratory capacity of the vocal folds when glottal insufficiency is treated with augmentative injections.  相似文献   

10.
Schneider-Stickler B 《HNO》2012,60(7):590-594
Voice disorders in the pediatric population are relatively common. The education of families, teachers and clinical staff on etiology and treatment of pediatric voice disorders have led to greater attention being paid to hoarseness in childhood and improving early detection of pediatric voice disorders. Pediatric voice problems can have a number of causes. Most commonly, childhood dysphonia is caused by vocal fold nodules due vocal ab- and misuse. Other reasons might be congenital laryngeal dysplasia, vocal fold cysts and laryngeal papilloma. Medical examination is necessary in order to initiate appropriate treatment. In the case of vocal fold cysts and laryngeal papilloma, phonosurgery is indicated. Vocal fold nodules should be treated by voice therapy in order to change vocal behaviour. If voice therapy fails, phonosurgical intervention is recommended, since vocal fold nodules can persist into adulthood with a negative impact on voice quality.  相似文献   

11.

Objectives

Carbon dioxide (CO2) laser cordectomy is considered one of the modalities of choice for treatment of early glottic carcinoma. In addition to its comparable oncological results with radiotherapy and open surgical procedures, it preserves of laryngeal functions including voice production. The aim of this study was to detect how the larynx compensates for voice production after different types of CO2 laser cordectomy for early glottic carcinoma together with assessment of the vocal outcome in each compensation mechanism.

Methods

One hundred twelve patients treated with CO2 laser cordectomy were classified according to their main postoperative phonatory site. Perceptual analysis of voice samples using GRBAS (grade, roughness, breathiness, asthenia, and strain) scale was done for 88 patients after exclusion of the voice samples of all female patients to make the study population homogenous and the samples of 18 male patients due to bad quality (4 patients) or unavailability (14 patients) of their voice samples and the results were compared with those obtained from control group that included 25 age-matched euphonic male subjects.

Results

Five types of laryngeal compensation were defined including: vocal fold to vocal fold, vocal fold to vocal neofold, vocal fold to vestibular fold, vestibular fold, to vestibular fold, and arytenoids hyper adduction. Characters changes of voice produced by each compensation type were found to be statistically significant except for breathiness, asthenia and strain changes in vocal fold to vocal fold compensation type.

Conclusion

The larynx can compensate for voice production after CO2 laser cordectomy by five different compensation mechanisms with none of them producing voice quality comparable with that of controls.  相似文献   

12.
Atomic force microscopy investigation of vocal fold collagen   总被引:1,自引:0,他引:1  
OBJECTIVES: Collagen is an important constituent of the vocal fold extracellular matrix and is necessary for providing tensile strength and maintaining tissue geometry. Traditional investigations of vocal fold collagen using light and electron microscopy do not provide information on the organization and mechanical properties of collagen in native topographic state. The primary objective of this study was to use Atomic Force Microscopy (AFM) to examine the surface characteristics and organization of collagen in the deep layer of the lamina propria at nanoscale resolution. STUDY DESIGN: Experimental in vitro design. METHODS: Freshly dissected porcine vocal folds were mounted on AFM discs and imaged under contact and tapping mode to obtain information on topographic distribution of collagen. RESULTS: AFM imaging of the deep layer of the lamina propria revealed dense, abundant collagen fibers with a characteristic banding pattern. The distribution of collagen was heterogeneous, with both hydrophilic and hydrophobic regions within a sample. CONCLUSIONS: AFM offers a useful tool to obtain topographic information about biologic samples at nanoscale resolution with minimal sample preparation. Mapping the topography and mechanical properties of vocal fold collagen is necessary for designing rheologically compatible bioimplants for the treatment of dysphonia resulting from vocal fold scarring and bowing.  相似文献   

13.
Surgical treatment of bilateral vocal fold paralysis must be undertaken if such a condition lasts 6-12 months or longer and causes dyspnoea. The purpose of the procedures is to assure proper airflow through the glottis and to preserve good voice and unimpaired swallowing. Modern endoscopic surgery of the glottis is performed with CO2 laser. The following paper presents results of laser posterior cordotomy performed in 17 patients aged 19-73 years suffering from bilateral vocal fold paralysis. Results and conclusions: In 7 patients the range of vocal fold resection had to be expanded. 3 individuals developed post-operative granulation in subglottal region. Spirometry and electroglottography were performed before and after the operation to assess the patients' laryngeal functions: respiration and voice quality. The results indicate that laser cordectomy was effective in the discussed group of patients.  相似文献   

14.
Su CY  Chuang HC  Tsai SS  Chiu JF 《The Laryngoscope》2005,115(3):528-533
OBJECTIVE: In treating early glottic carcinomas, the outcomes of endoscopic laser cordectomy have been proven to be valuable in local control, survival, and vocal function preservation. In some extended cases, however, laser cordectomy may leave patients with poor vocal function because of vocal fold deficit. This work assesses the vocal outcome of medialization laryngoplasty with bipedicled strap muscle transposition for vocal fold deficit resulting from laser cordectomy in early glottic cancer patients. STUDY DESIGN: A prospective clinical series. METHODS: Thirteen early glottic cancer patients who had vocal fold deficit caused by previous laser cordectomy underwent medialization laryngoplasty with bipedicled strap muscle transposition. The thyroid lamina on the cordectomy side was paramedially separated. The inner perichondrium was circumspectly raised from the overlying thyroid cartilage. After separating the thyrohyoid and cricothyroid membranes, the lamina was retracted laterally. A bipedicled strap muscle flap was then transposed into the area between the lamina and the paraglottic soft tissue. The thyroid cartilages were carefully sutured back in position. All patients received pre- and postoperative voice assessments comprising laryngostroboscopy and vocal function studies. RESULTS: Vocal enhancement was present in 92% (12/13) of patients after medialization laryngoplasty with strap muscle transposition. The glottal closure and maximal phonation time were noticeably improved by surgery. No dyspnea or other significant complications were observed in any patients. CONCLUSION: The outcomes show that bipedicled strap muscle transposition is a prosthesis-free, safe, and valuable laryngoplastic technique for correcting glottal incompetence caused by endoscopic laser cordectomy in early glottic cancer patients.  相似文献   

15.
OBJECTIVES: The purpose of the present study was to determine whether high-speed digital imaging with phonovibrogram (PVG) analysis would identify changes in vocal fold vibratory characteristics following prolonged reading (vocal fatigue) in subjects with normal voice to evaluate the voice effects of vocal loading. METHODS: Three healthy subjects' larynges were examined with an endoscopic high-speed imaging system at 4 different levels of vocal load. Vocal fold dynamics were segmented and processed by PVGs. The PVG images were quantitatively described by a parameter set enabling an individual characterization of vocal fold dynamics. To reveal differences between the subjects, we performed a linear discrimination analysis. Within each subject, the identification of vocal loading effects was performed by statistical analysis (1-way analysis of variance), and 2-tailed paired t-tests were used as a consistency check between left and right vocal fold sides. RESULTS: For each subject, the PVG analysis enabled a precise quantification of the entire range of vocal fold dynamics. Independently of the high-speed videos (vocal loads), each subject could be identified by his or her PVG parameters on linear discrimination analysis. In all subjects, the effect of vocal loading was reflected by alterations of PVG parameters representing the posterior opening and closing dynamics. Evaluation within subjects revealed slight asymmetric vibratory behavior between the left and right vocal folds, confirming earlier assumptions. CONCLUSIONS: Within the investigated subjects, vocal loading does affect the vibratory characteristics of the vocal folds. Left-right vocal fold vibratory asymmetries do occur in healthy voices and can be identified by PVGs. High-speed digital imaging in combination with PVG analysis seems to be a promising tool for investigation of vocal fold fatigue and disorders resulting even from small dynamic changes.  相似文献   

16.
OBJECTIVE/HYPOTHESIS: Standard laryngoscopy suffers from a lack of information about the actual size of the observed objects (i.e., vocal fold length and oscillating amplitudes). However, there is much interest in absolute measures for both clinical and research purposes. Therefore, a laser projection device has been developed that enables the precise determination of absolute units in endoscopic investigation during respiration and phonation. STUDY DESIGN: An experimental study in which 9 adults underwent high-speed endoscopy combined with a laser projection device. METHODS: The projection system consists of two parallel laser beams with a distance of 3.8 mm. It is mounted on the tip of a rigid endoscope, which is attached to a digital high-speed camera During development and design, examination situations were taken into account. Two laser spots are projected onto the vocal folds and enable the definition of a metric scale within the endoscopic image. Knowledge-based image processing algorithms were used for evaluation. RESULTS: First measurements of the vocal fold length during phonation were performed in a group of nine healthy male students. The determination of glottal length during phonation agrees with former results. Quantifying vocal fold velocities in absolute units makes it possible to estimate the initial collision forces. CONCLUSIONS: The presented laser projection system allows the determination of absolute measures in the larynx. Because of the simple functional principle, the system is open for use without digital high-speed recording as well. Absolute units may also be helpful in voice diagnosis and in monitoring during voice therapy.  相似文献   

17.
儿童复发性喉乳头状瘤临床治疗探讨   总被引:1,自引:0,他引:1  
目的:探讨和评价鼻内镜下显微电动吸切术协同激光治疗儿童喉乳头状瘤的可行性和手术疗效。方法:回顾性分析26例复发性喉乳头状瘤患儿的临床资料,采用鼻内镜下显微电动吸切术6例,鼻内镜下显微电动吸切术协同激光治疗,并对术腔创面涂透明质酸钠凝胶20例,对2种手术方式的疗效进行分析评价。结果:在鼻内镜下行显微电动吸切术切除复发性喉乳头状瘤的患儿,术后4周纤维喉镜检查发现喉乳头状瘤复发,术后2~3个月需再次手术;鼻内镜下微电动吸切术协同激光治疗的患儿,术后2~3周内,喉部创面再次辅助激光治疗4~8次,16例患儿治愈,术后随访3~8年无复发,4例患儿复发间隔延长。结论:鼻内镜下显微电动吸切术协同激光治疗能有效降低喉乳头状瘤的复发,该术式要求术后短期内反复多次激光辅助治疗,并且对创面采用了透明质酸钠凝胶,从而避免声带瘢痕过大和粘连,大大提高了患儿的发声质量,部分患儿通过该手术方案的治疗能完全治愈。  相似文献   

18.
OBJECTIVES: Selective vascular ablation (photoangiolysis) using pulsed lasers that target hemoglobin is an effective treatment strategy for many vocal fold lesions. However, vessel rupture with extravasation of blood reduces selectivity for vessels, which is frequently observed with the 0.45-ms, 585-nm pulsed dye laser. Previous studies have shown that vessel rupture is the result of vaporization of blood, an event that varies with laser pulse width and pulse fluence (energy per unit area). Clinical observations using a 532-nm wavelength pulsed potassium-titanyl-phosphate (KTP) laser revealed less laser-induced hemorrhage than the pulsed dye laser. This study investigated settings for the pulsed KTP laser to achieve selective vessel destruction without rupture using the avian chorioallantoic membrane under conditions similar to flexible laryngoscopic delivery of the laser in clinical practice. STUDY DESIGN: The chick chorioallantoic membrane offers convenient access to many small blood vessels similar in size to those targeted in human vocal fold. Using a 532-nm pulsed KTP laser, pulse width, pulse energy, and working distance from the optical delivery fiber were varied to assess influence on the ability to achieve vessel coagulation without vessel wall rupture. METHODS: Third-order vessels (n = 135) were irradiated: Energy (471-550 mJ), pulse width (10, 15, 30 ms), and fiber-to-tissue distance (1 mm, 3 mm) were varied systematically. RESULTS: Selective vessel destruction without vessel wall rupture was more often achieved by increasing pulse width, increasing the fiber-to-tissue distance, and decreasing energy. Vessel destruction without rupture was consistently achieved using 15- or 30-ms pulses with a fiber-to-tissue distance of 3 mm (pulse fluence of 13-16 J/cm). CONCLUSIONS: This study substantiates our clinical observation that a 532-nm pulsed KTP laser was effective for ablating microcirculation while minimizing vessel wall rupture and hemorrhage.  相似文献   

19.
OBJECTIVES: We describe the clinical features of granuloma of the membranous vocal fold (as opposed to granuloma of the vocal process, or "contact granuloma"), a poorly recognized sequela of microlaryngoscopic surgery. Membranous vocal fold granuloma may mimic the initial lesion in appearance, and thus be mistaken for recurrence. METHODS: We performed a retrospective review of cases from 2 institutions. RESULTS: Fifteen cases of membranous vocal fold granuloma from 2 institutions were identified. In all but 1 case, granuloma developed in the early postoperative period, within 8 weeks. Of the 15 cases, 10 followed laser resection of carcinoma. Five were noted following cold steel resection of benign lesions (2 papillomas, 2 cysts, 1 Reinke's edema). Technical aspects of these cases suggest that membranous vocal fold granulomas result from surgical violation of deep tissue planes and/or epithelial defects. All patients were treated with proton pump inhibitors. In 12 cases, the granulomas proved self-limited, resolving over weeks to months following surgery. Three patients underwent surgical removal of the lesion, which confirmed the diagnosis. One of these cases recurred and was treated nonsurgically. CONCLUSIONS: Granuloma should be suspected when a mass lesion appears at the surgical site early in the postoperative course. Surgical excision is generally not necessary and may provoke further growth of granulation tissue.  相似文献   

20.
Objectives: To measure the viscoelastic shear properties of hyaluronic acid, with and without fibronectin, and to compare them with those of the human vocal fold mucosa and other phonosurgical biomaterials. Methods: Viscoelastic shear properties of various implantable biomaterials (Teflon, gelatin, collagen, fat, hyaluronic acid, and hyaluronic acid with fibronectin) were measured with a parallel-plate rotational rheometer. Elastic and viscous shear properties were quantified as a function of oscillation frequency (0.01–15 Hz) at 37°C. Results: The shear properties of hyaluronic acid were relatively close to those of human vocal fold mucosal tissues reported previously. Hyaluronic acid at specific concentrations (0.5%–1%), with or without fibronectin, was found to exhibit viscous shear properties (viscous shear modulus and dynamic viscosity) similar to those of the average male and female vocal fold mucosa. Conclusions: According to a theory that establishes the effects of tissue shear properties on vocal fold oscillation, phonation threshold pressure (a measure of the ease of phonation) is directly related to the viscous shear modulus of the vibrating vocal fold mucosa. Therefore, our findings suggest that hyaluronic acid, either by itself or mixed with fibronectin, may be a potentially optimal bioimplant for the surgical management of vocal fold mucosal defects and lamina propria deficiencies (e.g., scarring) from a biomechanical standpoint.  相似文献   

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