Cricoid Research Articles

A Retrospective Study of Cricotracheostomy: Indications, Techniques, and Clinical Outcomes.

Cricotracheostomy (CT) is a surgical procedure for airway access that can be performed using 2 techniques: excising the cricoid cartilage (CTrach), or by creating an inverted U-shaped flap from the first tracheal ring (CTrachT). The aims of this study are to clinically evaluate factors such as patient background, complications, and stoma closure status in patients who underwent CT, and to compare the clinical outcomes between CTrach and CTrachT. Retrospective, cross-sectional study. Single-institution academic center. Records of patients who underwent CT at the University of Tokyo Hospital between 2014 and March 2024 were reviewed, detailing their demographics and clinical characteristics. We investigated differences in clinical backgrounds, complication risks for each surgical procedure, and factors contributing to stoma closure and complications after CT. The median age for patients undergoing CT was 70 years, predominantly male (76%), and most were malnourished. Common indications included low-lying larynx and obesity. Stoma closure was achieved in 16% of patients. Early complications were surgical site infection (9%) and subcutaneous emphysema (2%), with granuloma formation in 20%. The CTrach group had a significantly higher median age (P = .03), but other factors showed no significant differences. CTrachT was more often performed by board-certified specialists (P = .04). Stoma closure rates and complications were not significantly influenced by any single factor. CT presents a viable option with minimal postoperative complications for patients wherein conventional tracheotomy may be more challenging, such as in low-lying larynx, obesity, advanced age, and poor nutritional status.

Clinical outcomes after post-operative radiotherapy for breast cancer patients presenting with ipsilateral supraclavicular metastasis: considerations on the cranial border of irradiation field.

Disease recurrence at lower neck adjacent to ipsilateral supraclavicular (SCV) region represents a concern in locally advanced breast cancer patients presenting with SCV metastasis at diagnosis. This study aims to report the outcomes following post-operative radical radiation therapy and discuss the reasonable cranial border of the irradiation field for N3c patients. Between July 2016 and January 2022, a total of 268 patients were eligible for analysis. The endpoints included in-field and out-field cervical failures, local-regional recurrence-free survival (LRRFS), SCV recurrence-free survival (SRFS), distant metastasis-free survival (DMFS), relapse-free survival (RFS), and overall survival (OS). During a median follow-up of 37months (range 3-89months), 17 patients (6.3%) developed local-regional recurrence as the first recurrence event, with 13 having concomitant distant-metastasis (DM); 56 patients (20.9%) had DM alone. The 3-year rates of LRRFS, SRF, DMFS, RFS, and OS were 92.3%, 94.5%, 74.5%, 73.0%, and 90.0%, respectively. 89.2% of patients received RT with the cranial border at the top of hyoid bone, and 95.1% of patients received a boost not exceeding the level of cricoid cartilage. A total of 11 patients (4.1%) developed ipsilateral SCV failure, and 3 patients (1.1%) experienced cervical failure, including 2 in-field failures and 1 out-field failure. Neoadjuvant systemic therapy (NST) was administered to 234 patients (87.3%). In the multivariate analysis, non-ypN0, triple-negative subtype and cT4 at diagnosis were predictors of worse SRFS and RFS in NST subgroup. Our findings suggest that radical RT with cranial border of irradiation field at the hyoid bone level lead to excellent local-regional control, and out-field cervical failure was rare. The irradiation field might not extend to mastoid process.

Asphyxialdeath due to fracture of thyroid cartilage, cricoid cartilage and arytenoid cartilage as result of blunt trauma of neck in a motorcycle accident:An Autopsy report

Laryngeal fracture is rare but fatal traumatic injury which is mainly caused by severe blunt trauma from interpersonal violence, motor vehicle accident or sports injuries. Laryngeal fracture can lead to severe airway collapse and death.Mortality decreases to less than 5% once the airways made patent and laryngeal injuries are corrected.People must take motorcycle riding safety course to learn how to ride safely. Always follow traffic rules. The motor vehicle accident can be prevented largely through public awareness and education

Enhancing prosthesis stability at the cricoid cartilage in equine laryngoplasty using 3-D-printed laryngeal clamps: An ex vivo model study.

To assess a three-dimensional (3-D)-printed laryngeal clamp (LC) designed to enhance the anchoring of laryngeal prostheses at the cricoid cartilage. Ex vivo biomechanical study. A total of 22 equine larynges. Two experimental groups included larynges with standard prosthetic laryngoplasty (PL; n = 10) and larynges with prosthetic laryngoplasty modified with laryngeal clamps (PLLC; n = 10). All constructs underwent 3000 cycles of tension loading and a single tension to failure. Recorded biomechanical parameters included maximum load, actuator displacement, and construct failure. Finite element analysis (FEA) was performed on one PL and one PLLC construct. The maximum load at single tension to failure was 183.7 ± 46.8 N for the PL construct and 292.7 ± 82.3 N for the PLLC construct (p = .003). Actuator displacement at 30 N was 1.7 ± 0.5 mm and 2.7 ± 0.7 mm for the PL and PLLC constructs, respectively (p = .011). The cause of PL constructs failure was mostly tearing through the cartilage whereas the PLLC constructs failed through fracture of the cricoid cartilage (p = .000). FEA revealed an 11-fold reduction in the maximum equivalent plastic strain, a four-fold reduction in maximum compressive stress, and a two-fold increase in the volume of engaged cartilage in PLLC constructs. The PLLC constructs demonstrated superior performance in biomechanical testing and FEA compared to standard PL constructs. The use of 3-D-printed laryngeal clamps may enhance the outcomes of laryngoplasty in horses. In vivo studies are necessary to determine the feasibility of performing laryngoplasty using the laryngeal clamp in horses.

Evaluating the precision of ultrasound versus computed tomography-guided measurement of cricoid cartilage diameter for double-lumen tube selection in thoracic surgery: A randomised comparative study.

Precise airway management is vital in thoracic surgeries to ensure patient safety and optimal outcomes. Choosing the correct double-lumen tube (DLT) size is challenging, as it typically relies on height, gender and subjective experience. This study investigates using ultrasonography (USG) and computed tomography (CT) to measure cricoid cartilage diameter for objective DLT sizing. In a randomised study, 120 adult patients undergoing elective thoracic surgery were randomised to three groups: Group A (DLT size determined by USG), Group B (DLT size determined by CT) and Group C (DLT size determined by conventional methods based on height and gender). The primary outcome variable was the appropriateness of DLT size. Secondary outcome variables were the degree of lung collapse and sore throat. Student's t-test and ꭓ2 test were used to analyse continuous and dichotomous variables, respectively. DLT sizing based on cricoid cartilage diameter improved the accuracy, with inappropriate sizes found in 25% in the conventional group, 5% in the USG group and 2.5% in the CT group (P < 0.05). Lung collapse was better in the USG (excellent in 92.5%) and CT (95%) groups compared to the conventional group (70%) (P < 0.05). Moderate sore throat was higher in the conventional group (37.5%) compared to the USG (5%) and CT groups (7.5%). The study demonstrates that USG- and CT-guided measurements of cricoid cartilage diameter are reliable and effective methods for determining DLT size in thoracic surgery compared to conventional methods.

Influence of catheter thickness on respiratory physiology during less invasive surfactant administration in extremely preterm infants.

Delivering surfactant via thin catheters (minimal-invasive surfactant therapy (MIST); less invasive surfactant administration (LISA)) has become a common procedure. However, the effect of tracheal obstruction caused by catheters of different sizes on tracheal resistance in extremely low gestational age newborns (ELGANs) is unknown. To investigate the effect of catheters size 3.5, 5 and 6 French on airway resistance in ELGANs of 23-28 weeks gestational age during LISA, we performed calculations based on Hagen-Poiseuille's law and compared these with a clinically and physically more accurate method: computational fluid dynamics (CFD) simulations of respiratory airflow, performed in 3D virtual airway models derived from MRI. The presence of the above catheters decreased the cross-sectional area of the infants' tracheal entrance (the cricoid ring) by 13-53%. Hagen-Poiseuille's law predicted an increase in resistance by 1.5-4.5 times and 1.3-2.6 times in ELGANs born at 23 and 28 weeks, respectively. However, CFD simulations demonstrated an even higher increase in resistance of 3.4-85.1 and 1.1-3.5 times, respectively. The higher calculated resistances were due to the extremely narrow remaining lumen at the glottis and cricoid with the catheter inserted, resulting in a stronger glottal jet and turbulent airflow, which was not predicted by Hagen-Poiseuille. Catheter thickness can greatly increase tracheal resistance during LISA-procedures in ELGANs. Based on these models, it is recommended to use the thinnest catheter possible during LISA in ELGANs to avoid unnecessary increases in airway resistance in infants already experiencing dyspnea due to respiratory distress syndrome.

Laryngeal chondrosarcoma, a 30-year series

Introduction and objectivesLaryngeal chondrosarcoma is a rare laryngeal pathology arising from cartilaginous structures and is predominantly found in the cricoid cartilage. This study investigates its presentation, treatment modalities and patient outcomes. Patients or materials and methodsRetrospective study of laryngeal chondrosarcoma cases followed from 1992 to 2022 in the Otorhinolaryngology department of a cancer center - Instituto Português de Oncologia de Lisboa. Statistical analysis was made with Microsoft Excel® and SPSS®. ResultsWe identified 16 cases, of which two-thirds were male, with an average age of 59.6 years, and only 24% of them had a history of smoking. The commonest presentation was indolent dysphonia and/or dyspnea, and the posterior arch of the cricoid cartilage was the most affected place. Although histopathological studies after biopsy were often inconclusive, surgery emerged as the first-line of treatment for all patients. Larynx microsurgery with lesion debulking was the most frequent surgical approach (47%) followed by partial laryngectomy (24%). Neither adjuvant radiotherapy (RT) nor chemotherapy was administered in any of the cases. There was residual tumor in 23% of the cases so half of these patients were in watchful waiting while the other part underwent further microsurgery or total laryngectomy. Only one patient with recurrence received RT. Disease-specific survival rate at 1 and 5 years was 97% and 91%, respectively. ConclusionLaryngeal chondrosarcoma etiology is still unknown and is effectively treated with surgery, with a generally favorable prognosis. The main concern lies in its propensity to relapse, highlighting the importance of watchful follow-up.

Morphometry of adult cricoid cartilage in Nepalese cadavers: a cross-sectional observational study

Background: Cricoid cartilage is crucial during endotracheal intubation, yet its dimensions in the Nepali population remain uncharacterized. This study aimed to measure cricoid cartilage dimensions in adult Nepalese. Methods: A total of 105 cadavers (75 males, 30 females) were dissected at *** Medical Campus, Nepal. Measurements of outer and inner transverse and anteroposterior diameters, as well as heights of the cricoid arch and lamina, were taken using digital vernier calipers. Statistical analyses included gender comparisons and correlations with age. Results: The mean age of the 105 cadavers studied was 34.11 years (SD = 12.08). The measurements of outer anteroposterior diameter, outer transverse diameter, inner anteroposterior diameter, inner transverse diameter, arch height and lamina height were respectively 22mm (SD=4), 21mm (SD=4), 18mm (SD=3), 17mm (SD=3), 9mm (SD=3) and 24mm (SD=4). Inner AP (p = 0.009) and inner TR (p = 0.021) measurements correlated significantly with age. Males had significantly larger cricoid cartilage dimensions than females (p &lt; 0.001). Conclusions: This study provided essential data for selecting appropriately sized endotracheal tubes in Nepalese patients, reducing airway complications. It underscored the need to tailor medical devices to local anatomical variations, supporting advancements in biomechanical modeling and medical research.

Comprehensive Guide to Transoral Endoscopic Thyroidectomy Vestibular Approach: Step-by-Step Technique

AbstractTransoral endoscopic thyroidectomy vestibular approach (TOETVA) is a minimally invasive surgical technique that offers safety comparable to conventional open thyroidectomy, with the added benefit of superior cosmetic outcomes due to the absence of visible scars. This innovative approach is gaining popularity worldwide as an alternative for patients seeking thyroid surgery without postoperative scarring. TOETVA involves positioning the patient supine with slight neck extension under general anesthesia. The procedure uses three trocars placed via midline and lateral incisions, with a 10-mm 30-degree laparoscope for visualization. Preoperative care includes cleaning the surgical area and administering intravenous antibiotics to prevent infection. The technique mirrors conventional thyroidectomy but utilizes standard laparoscopic instruments. It emphasizes the precise identification and preservation of critical anatomical structures, such as the cricoid cartilage, thyroid isthmus, trachea, carotid artery, superior laryngeal nerve, and recurrent laryngeal nerve. The use of an energy device and careful dissection help minimize bleeding and reduce nerve injury risks. Superior pole management and meticulous handling of the thyroid lobe ensures optimal outcomes. The growing popularity of TOETVA indicates a shift toward minimally invasive thyroid surgery, with TOETVA emerging as a leading method. This paper provides a comprehensive overview of the procedure, highlighting its benefits and critical aspects of its successful implementation.

Diagnostic accuracy of airway ultrasound in confirming the endotracheal tube depth in critically ill children

BackgroundChest X-ray, the established standard of confirming endotracheal tube (ETT) position, has important drawbacks including radiation exposure. Point-of-care airway ultrasound, which has been insufficiently studied in children, can overcome these problems. Materials and methodsThis was a prospective cross-sectional study done on children aged 2 months to 17 years undergoing intubation with cuffed ETT in the PICU. The ETT cuff was filled with saline and three ultrasonographic techniques were used– 1) Suprasternal (SS) method 2) Cricoid (CC) metho and 3) Tracheal ring (TR) method. Position of the ETT as determined by ultrasound and X-ray were compared. The main outcomes were sensitivity, specificity, and area under curve (AUC) for ultrasound-based methods vs. X-ray. For the TR method, concordance between the X-ray and ultrasound categories were taken. ResultsTotal 62 patients were enrolled. The sensitivity and specificity of SS method were 71% (95% CI: 57–83%) and 100% (40–100%). The CC distance method had an AUC of 0.94 (95% CI: 0.86, 1.0). In the TR method, 98% of correct position on X-ray were correctly classified by USG. The agreement between X-ray and ultrasound categories with the cuff between the first and third tracheal rings, was very good [kappa (95% CI): 0.87 (0.70, 1.00), p ≤0.001)]. ConclusionBedside ultrasound is a good method to confirm ETT depth in children. The tracheal ring method had the best diagnostic accuracy and is easy to perform. The new method using cricoid cuff distance needs further validation in different ICU settings.

Radiological assessment of the dissection area in supraomohyoid neck dissection

PurposeThe current supraomohyoid neck dissection (SOHND) is performed above the omohyoid muscle to dissect levels I, II, and III in the levels of cervical lymph nodes. However, the anatomical boundary between levels III and IV is the inferior border of the cricoid cartilage. We investigated the anatomical relationship between the omohyoid muscle and cricoid cartilage using contrast-enhanced CT (CE-CT) images to assess the validity of the current SOHND.MethodsCE-CT images of the head and neck regions in patients were reviewed. The patients were divided into two groups: “malignant tumors” and “others”. The vertebral levels corresponding to the positions of anatomical structures such as the intersection of the omohyoid muscle and internal jugular vein (OM-IJ), and the inferior border of the cricoid cartilage (CC), were recorded.ResultsThe OM-IJ was located around the seventh cervical to the first thoracic vertebra. There was a significant difference between the malignant tumor and others groups in females (p = 0.036). The CC was located around the sixth to seventh cervical vertebrae. There was a significant sex difference in each group (malignant tumor: p < 0.0001; others: p = 0.008). Both sexes tended to have lower OM-IJ than CC, and females had significantly lower OM-IJ than males.ConclusionThis study provides clear anatomical evidence showing the difference between the SOHND dissection area and levels I, II, and III. It could be considered that in most cases SOHND invades level IV, not just levels I, II, and III, especially in female patients.

Evaluation of neck ultrasound measurements as a difficult airway predictor: A prospective observational study.

This study aimed to investigate the relationship between cervical measurements and difficult airways using ultrasonographic measurements. American Society of Anesthesiologists grade I to III, male or female, 120 adult patients, undergoing elective surgery were enrolled in the study. The study involved measuring the distance of the trachea, cricoid cartilage, thyroid cartilage, vocal cord anterior commissure, and hyoid bone to the skin using a 10 to 13 MHz linear ultrasound probe in the transverse plane. Additionally, the length of the cricothyroid and thyrohyoid membranes, along with their distance from the skin, were measured using the probe in the sagittal plane. Subsequently, another experienced anesthesiologist conducted mask ventilation and intubation after the patient's induction of general anesthesia. Throughout this process, the patient was assessed for difficulties in mask ventilation, laryngoscopy, and intubation. 28 (23.3%) patients had a difficult airway. Analyzing the measurements associated with difficult airways, the most reliable predictor was the epiglottis midline-skin distance [AUC (area under the curve): 0.847, P < .001, cutoff: >19.9, sensitivity: 78.6%, specificity: 79.4%]. Additionally, other factors such as hyoid bone to skin distance, thyroid cartilage to skin distance, thyrohyoid membrane to skin distance, and vocal cord anterior commissure-skin distance were also identified as predictors for a difficult airway. The increase in the distance of the epiglottis midline, vocal cord anterior commissure, hyoid bone, thyrohyoid membrane, and thyroid cartilage to the skin at the level of the isthmus measured by ultrasonography is predictive of difficult airways. Based on our study outcomes, we assert that ultrasonographic evaluation can be used in the prediction of difficult airways.

The use of thyroid flap for preserving laryngeal function in laryngeal cancer.

Preserving laryngeal function after partial laryngectomy for laryngeal cancer is an important consideration. Therefore, we examined the use of thyroid flaps for this purpose. We analyzed 21 patients who underwent thyroid flap reconstruction after partial laryngectomy for laryngeal cancer in the Department of Otorhinolaryngology Head and Neck Surgery, the Second Xiangya Hospital of Central South University from January 2010 to January 2020. All patients were male and aged 51-64 years. Seventeen patients underwent modified tracheocricohyoidoepiglottopexy, and the remaining four patients underwent modified cricohyoidopexy. The thyroid flap was pedicled from the superior thyroid blood vessels. In the modified tracheocricohyoidoepiglottopexy, the flap was turned to cover the area between the tracheal ring and epiglottis to reconstruct the anterior wall of the cricoid cartilage, whereas in the modified cricohyoidopexy, it was turned over between the cricoid cartilage and tongue root to reduce anastomotic tension. A total of seven patients underwent radiotherapy and chemotherapy after surgery. Thyroid flap reconstruction was successfully performed in all patients. The postoperative hospitalization time was 9-21 days, the postoperative nasal feeding time was 18-47 days, and the tracheotomy tube was removed 30-160 days after surgery. No laryngeal stenosis, flap necrosis, bleeding complication, or dysfunction of the thyroid and parathyroid glands was observed after surgery. Two patients experienced wound infections about 1 week after discharge and were admitted again for antibiotic treatment. After dressing and compressing the neck wound, the patients were discharged. Three patients experienced local tumor recurrence after surgery, two of whom did not receive radiotherapy and chemotherapy after modified tracheocricohyoidoepiglottopexy. No patients had distant metastasis after surgery. Thyroid flaps have significant application value in the reconstruction of the laryngeal cavity after partial laryngectomy for laryngeal cancer. It has high safety and feasibility, convenient surgical procedure, and satisfactory postoperative outcomes.

The previously undescribed variant of the thyrohyoid muscle and its potential impact on surgical procedures

The thyrohyoid muscle belongs to the infrahyoid group located in the carotid triangle. It normally originates from thyroid cartilage and inserts into hyoid bone. Quite often, it is continuous with the sternohyoid muscle. Furthermore, there are variants that have their origin in the cricoid cartilage only, however, this occurs very rarely. During anatomical dissection, a two-headed variant of this muscle was found. One head had its origin in the cricoid cartilage and the other in the thyroid cartilage. This variant of thyrohyoid had not been previously described in the available literature. Therefore, we believe that it may be referred to as the cricothyrohyoid muscle. As the thyrohyoideus is often used as a landmark during surgical procedures in the prelaryngeal area and as a muscle graft, a thorough knowledge of its anatomy and variation is extremely important. We speculate that the two-headed version of this muscle may be problematic during surgical procedures in this region, however, it may also provide more options as a muscular graft.

Endotracheal tube cuff position in relationship to the walls of the trachea: A retrospective computed tomography-based analysis.

The use of cuffed endotracheal tubes (ETTs) has become the standard of care in pediatric practice. The rationale for the use of a cuffed ETT is to minimize pressure around the cricoid while providing an effective airway seal. However, safe care requires that the cuff lie distal to the cricoid ring following endotracheal intubation. The current study demonstrates the capability of computed tomography (CT) imaging in identifying the position of the cuff of the ETT in intubated patients. The study included patients ranging in age from 1 month to 10 years who underwent neck and chest CT imaging that required general anesthesia and endotracheal intubation. The location of the ETT and of the cuff within the airway was determined from axial CT images at three levels (proximal, middle, and distal). Anatomical orientations were tabulated, and percent chances of each orientation were determined for the ETT and the cuff. The study cohort included 42 patients ranging in age from 1 to 114 months. An ETT with a polyvinylchloride cuff was used in 24 patients, and an ETT with a polyurethane cuff was used in 18 patients. The ETT was located near the posterior wall of the trachea in approximately 24-38% of patients, being most likely to be centrally located at the proximal end and at its mid-portion. The middle part of the cuff was most likely to be positioned in the mid-portion of the trachea but tended to skew anteriorly at both the proximal and distal ends. This is the first study using CT imaging to identify the uniformity of cuff inflation within the trachea in children. With commonly used cuffed ETTs, cuff inflation and the final position of ETT cuff within the tracheal lumen were not uniform. Future investigations are needed to determine the reasons for this asymmetry and its clinical implications.

Laryngeal chondromas: Current knowledge and future directions.

Cartilaginous tumors of the larynx are rare, representing less than 1% of all laryngeal tumors. Chondromas are benign mesenchymal tumors characterized by a slow-paced growth, primarily originated in the cricoid cartilage, followed by the thyroid, arytenoid, and epiglottic cartilages. This scoping review aims to understand the extent of evidence on the epidemiology, clinical characteristics, morbidity, and recurrence of the laryngeal chondroma (LC). MEDLINE (Ovid), Embase (Elsevier), Web of Science (Clarivate), Cochrane Central Register of Controlled Trials and Systematic Reviews, Lilacs, Scopus, and Google Scholar databases. The scoping review was conducted from 1816 to 2023, for observational studies describing LC. Titles and abstracts were screened for relevance, followed by an evaluation of the full text for eligibility. The data were collected from the qualifying articles, and a narrative summary of the outcomes was prepared. One hundred and nineteen studies met the inclusion criteria. Ninety-four case reports, 22 case series, and 3 cohorts. Two hundred and four participants with a diagnosis of LC were described. Male:female ratio was 2.8:1. The most common localization was the cricoid (113; 47.08%), followed by the thyroid (45; 18.75%), and the arytenoid cartilage (27; 11.25%). Dyspnea (78.85%) and hoarseness (74.28%) were the most reported symptoms. The recurrence rate was 11.25%, and complications were uncommon following the resection. This scoping review found a low-frequency rate over all the cartilaginous laryngeal tumors. Most patients were treated with resection, with a low rate of malignancy conversion. This population has low attributable mortality, morbidity, and recurrence according to the current literature.

Equine laryngoplasty: Effects of three anchoring techniques in the muscular process and three positions for suture implantation in the cricoid cartilage.

To compare the effects of three anchoring techniques in the muscular process and three positions of laryngoplasty suture implantation in the cricoid cartilage on abduction of the arytenoid cartilage and interaction with the cricoarytenoid dorsalis (CAD) muscle compartments. Experimental study. Twenty-two cadaveric equine larynges. Three implantation techniques were assessed in the left muscular process. They were the use of a titanium corkscrew (CS), a standard caudal passage using a Jamshidi needle (JCa), and a standard cranial passage using a Jamshidi needle (JCr). Each was assessed in combination with three caudal locations in the cricoid cartilage (right, left, and left lateral). Each suture combination was tightened to submaximal abduction (Dixon grade 2). Force on the suture, degree of larynx caudal rotation, and CAD muscle indentation were evaluated. The force required for optimal arytenoid cartilage abduction was lower (p < .01) for constructs involving a CS (7.45 ± 4 N). The CS also resulted in lower (p < .01) CAD muscle indentation (2.01 ± 1.25 mm) and less larynx rotation (9 ± 3.87°; adjusted p < .05). When inserted into the muscular process at the CAD tendon insertion point, the biomechanical properties of the CS reduced the force required for optimal arytenoid cartilage abduction. The CS also minimized interference with the CAD muscle compartments and reduced caudal displacement of the left arytenoid cartilage when it was under suture tension. The CS implantation avoided larynx deformation and muscle interaction, offering the possibility to combine a nerve graft and laryngoplasty as a treatment for recurrent laryngeal neuropathy.

Aging Larynx: Molecular and Cellular Aspect

In South Korea, the elderly population is rapidly growing, projected to reach 20.6% by 2025. With increased social engagement among older individuals, the demand for voice-related interventions rises. Age-related changes in these structures impact vocal function and quality. Understanding the mechanisms underlying these changes is crucial for developing effective therapeutic approaches. The aging of the larynx occurs in each part of the cartilage, muscles, and vocal folds. The change in cartilage is most prominently characterized by ossification, which begins in the twenties and accelerates significantly after the age of 60. This ossification is particularly evident in the thyroid and cricoid cartilages. Muscle aging is characterized by a decrease in muscle fiber diameter, a reduction in gender differences, an increase in the proportion of type I muscle fibers, along with a decrease in myocyte function and the deposition of extracellular matrix and adipocytes. In the vocal folds, collagen increases, while type III collagen, which is involved in healing, decreases. Additionally, collagen production and breakdown decrease, as well as hyaluronic acid levels and factors involved in mucosal vibration, such as surface elastic fibers.

Intramuscular nerve distribution of the sternocleidomastoid muscle for the botulinum toxin injection.

The aim of this study is to define the intramuscular nerve distribution of the sternocleidomastoid muscle (SCM) and the innervation zones (IZ) to describe the optimal botulinum toxin injection sites. The cricoid cartilage (CC), laryngeal prominence (LP) and hyoid bone (HB) and angle of mandible (AM) were determined as landmarks. The length of the muscles were measured between the sternoclavicular joint and tip of the mastoid process. SCM was evaluated in two parts as anterior and posterior divided by the line where the length of the muscle was measured. Measurements were made to define the relationships of the SCM with common carotid artery, internal and external jugular veins. IZ were described according to these vessels. Afterwards, Modified Sihler's staining technique was applied to expose the intramuscular nerve distribution. The average length of SCM was 160,1mm. Motor entry point of the accessory nerve fibers were between the AM-HB lines, in the range of 30-40% of the muscle length, and in the posterior part of the muscles. IZ were between the HB-CC lines in the anterior and posterior part. When this interval was examined according to the vessels, the optimal injection sites were between the LP-CC lines. This study shows the position of the intramuscular nerve fibers endings of the SCM according to the chosen landmarks and the relationship of the IZ with the vessels to prevent complications. These results can be used as a guide for safe and effective botulinum toxin injections with optimal quantities.

Regional variations and sex-related differences of stiffness in human tracheal ligaments.

There have been numerous studies focused on the stiffness of tracheal cartilage. However, no research has been conducted specifically on the annular ligament, nor have any regional differences in the annular ligament been identified. The purpose of this study was to investigate the stiffness of the ligaments present between the thyroid, cricoid and tracheal cartilages. The ligaments were identified in the cervical region of living subjects with ultrasonography. The stiffness of the ligaments was measured from the body surface using a digital palpation device (MyotonPRO). Since it is impossible to measure the entire trachea in a living subject, an additional measurement was performed on human cadavers. Both in vivo and cadaveric investigations found that the stiffness of annular ligaments decreased gradually from the superior to inferior parts. There was no difference in the stiffness between males and females in the superior part of the trachea. However, the stiffness of the middle and inferior parts was predominantly higher in females than in males. Furthermore, males showed significant differences in stiffness between the superior and middle parts, while females showed no significant differences. These results reveal that there are regional and sex-related differences in the stiffness of human tracheal ligaments.