Cricoid Level Research Articles

A surgical conundrum: Managing primary tracheal adenoid cystic carcinoma with preservation of larynx

Title: A surgical conundrum: managing primary tracheal adenoid cystic carcinoma with preservation of larynx. Introduction: Tracheal tumors are extremely uncommon. The incidence of tracheal tumors is 0.09–0.2% out of which 10% are Adenoid cystic carcinoma. The origin of adenoid cystic carcinoma is from the submucosal glands of the tracheal tree. It is typically regarded as a low-grade malignancy with a favorable prognosis. Case Presentation: A 35 years old male patient came to Out Patient Department with chief complaints of change in voice since 6 months and stridor since 1 week. On Indirect laryngoscopy there was left sided vocal cord palsy with submucosal swelling in subglottic area compromising the airway. Contrast Enhanced Computed Tomography revealed a hyperintense lesion of about 5.5 cm craniocaudally in the posterolateral aspect of the subglottic trachea and inferior border of the cricoid pushing left thyroid lobe anterolaterally along with significant obstruction of the airway at the level of cricoid. An emergency tracheostomy was done at lower level to secure the airway. Flexible bronchoscopy showed a 1.5-2cm stenotic segment obstructing 50 to 75% of the airway in a subglottic region with left vocal cord palsy. A biopsy of the lesion took externally which came as an Adenoid Cystic Carcinoma. On Magnetic Resonance Imaging there was no involvement of the nerve or metastasis. Wide local excision of the lesion involving tracheal resection with cricotracheal anastomosis and Montgomery Tube insertion was done followed by chemoradiation. Montgomery tube was successfully removed and the patient satisfactorily decannulated. Conclusion: Adenoid cystic carcinoma should be considered as a differential diagnosis in patients with changes in voice and stridor. As adenoid cystic carcinoma is very slow-growing tumor so instead of being so radical a combined approach that gives a functional larynx and better quality of life should opt.

Pediatric application of cuffed endotracheal tube: a secondary publication translated into Korean

A young child’s larynx was formerly believed to be narrowest at the cricoid level, circular in section, and funnel shaped. This supported the routine use of uncuffed endotracheal tubes in young children despite the benefits of cuffed tubes, such as lower risk for air leakage and aspiration. In the late 1990s, evidence supporting the pediatric use of cuffed tubes emerged largely from anesthesiology studies, while some technical flaws of the tubes remained a concern. Since the 2000s, imaging-based studies have clarified laryngeal anatomy, revealing that it is narrowest at the glottis, elliptical in section, and cylindrical in shape. The update was contemporaneous with technical advances in the design, size, and material of cuffed tubes. The American Heart Association currently recommends the pediatric use of cuffed tubes. In this review, we present the rationale for using cuffed tubes in young children based on our updated knowledge of pediatric anatomy and technical advances.

Pediatric Application of Cuffed Endotracheal Tube.

A young child's larynx was formerly believed to be narrowest at the cricoid level, circular in section, and funnel shaped. This supported the routine use of uncuffed endotracheal tubes (ETTs) in young children despite the benefits of cuffed ETTs, such as lower risk for air leakage and aspiration. In the late 1990s, evidence supporting the pediatric use of cuffed tubes emerged largely from anesthesiology studies, while some technical flaws of the tubes remained a concern. Since the 2000s, imaging-based studies have clarified laryngeal anatomy, revealing that it is narrowest at the glottis, elliptical in section, and cylindrical in shape. The update was contemporaneous with technical advances in the design, size, and material of cuffed tubes. The American Heart Association currently recommends the pediatric use of cuffed tubes. In this review, we present the rationale for using cuffed ETTs in young children based on our updated knowledge of pediatric anatomy and technical advances.

Plain Radiographic Analysis of Laryngeal Dimensions in Young Children: Normal versus Croup.

(1) Background: Contrary to a tenet of the funnel-shaped pediatric larynx with the cricoid level being narrowest, recent studies show the glottis and subglottis as the narrowest levels. To locate the functionally narrowest level of the larynx, we reported normal laryngeal dimensions and their croup-related changes in young children. (2) Methods: We reviewed normal plain neck radiographs recorded for the evaluation of minor trauma or foreign bodies in 504 children aged ≤4 years who visited the emergency department from 2016 through 2021. Using computed tomography-based localization of the glottis, we radiographically defined the subglottis and cricoid. At these levels, we measured diameters and calculated cross-sectional areas (CSAs) on the radiographs. The values were compared to the equivalent values of a 1:1 age-matched population with croup. (3) Results: In the study population (n = 401), the narrowest diameter and CSA were observed in the glottis. In detail, the mean anteroposterior/transverse diameters were 9.8/3.4 mm at the glottis, 8.5/5.6 mm at the subglottis, and 7.4/6.8 mm at the cricoid (p < 0.001), respectively. In the same order, the mean CSAs were 26.5, 38.1, and 40.5 mm2 (p < 0.001). All dimensions were narrower in the croup population (p < 0.001). We found croup-related narrowing, namely reductions in the transverse diameter and CSA that were more severe closer to the glottis (p < 0.001), without differences per level in the anteroposterior diameter. (4) Conclusions: This study confirms the glottis as the narrowest level of the larynx in young children. In addition, level-based differences in croup-related narrowing suggest some point between the glottis and subglottis as the functionally narrowest level.

Comparison of Ultrasonography with Cole’s Formula to Determine Appropriate Endotracheal Tube Size in Pediatric Population

Introduction: Recently, ultrasonography (USG) has gained popularity in perioperative airway management . One of the commonest method to select endotracheal tube in pediatric patients is Cole’s formula. Our study was conducted to assess if there was a measurable difference in the appropriateness of the endotracheal tubes as selected by the two methods. Methods: The study group included 68 children scheduled for elective surgeries under general anesthesia with endotracheal intubation in an randomized prospective manner. The size of endotracheal tube was calculated using Cole’s formula in group A. In group B, ultrasound was done to measure the subglottic transverse diameter at the level of cricoid to find the largest outer diameter of tube . Results: Ultrasonography group measuring the subglottic diameter was found to have more appropriately sized tubes than age-based Cole's formula (76.5% Vs 58.8% p=0.007). The pressure equilibrated measured (13.2 ± 5.2 cm of H2O in age based group and 17 ± 4.5 cm of H2O in ultrasonography group) was statistically significant (p=0.002). Also the incidence of selecting an inappropriately small sized ET tube was lower in the ultrasound group (5.9% Vs 35.3%). There were no significant differences in the number of intubation attempts and mean time required for intubation between the two groups. Conclusion: Ultrasonographic method is a suitable alternative tool in predicting the size of uncuffed endotracheal tube in pediatric population than age-based Cole’s formula.

Tracheal Length Measurement in Intubated Neonates to Guide the Design and Use of Endotracheal Tube Glottic Depth Markings.

Background: Data on neonatal tracheal length are needed to inform the standardization of safety features for endotracheal tubes (ETTs) such as glottic depth markings. Laryngotracheal airway measurements are available from digital imaging in infants and children but not in neonates. We aimed to determine the tracheal length (TL) of intubated preterm and term neonates. Methods: An observational study was performed on 57 neonates of 22–42 weeks’ gestation and <1 week of age. Two clinicians independently reviewed 153 digital chest radiographs to determine the carina position and TL. TL was measured from carina to mid-C4 (cricoid level). We analyzed interrater agreement (within 0.5 vertebral levels) on the position of the carina and TL. TL was plotted as a function of gestational age and weight, using graphical and regression analyses. Results: Carina position ranged from T3 to T5.5, with an interrater agreement of 95%. On image pairs concordant for carina position, TL determinations were virtually identical between readers (mean difference 0.1 mm, 95% CI −0.5–0.6 mm). Average mid-tracheal length overlies the body of T1. In infants aged less than 32 weeks’ gestation, the mid-trachea lies <20 mm from the carina or the larynx. TL linearly correlates with gestational age, but correlation with birthweight best fits a segmented regression with a node at 1 kg. Conclusions: The functional length of the laryngotracheal airway can be reliably measured in sick neonates. It correlates well with gestational age and birthweight, and this information can inform the redesign of ETT markings to promote the safer use of these devices.

Locoregional Extension Patterns of Nasopharyngeal Carcinoma Detected by FDG PET/MR.

PurposeWe sought to define the locoregional extension patterns of nasopharyngeal carcinomas (NPCs) by positron emission tomography (PET)/magnetic resonance imaging (MRI) and to improve clinical target volume (CTV) delineation.MethodsBetween May 2017 and March 2021, 331 consecutive patients with nonmetastatic NPCs who underwent pretreatment, simultaneous whole-body PET/MRI for staging were included in this study.ResultsThe high-risk regions included the base of the sphenoid bone, the prestyloid compartment, prevertebral muscle, foramen lacerum, medial pterygoid plate, sphenoidal sinus, clivus, petrous apex, and foramen ovale. When the high-risk regions were invaded, the incidence rates of tumor invasion into the medium-risk regions increased. In contrast, when the high-risk regions were not involved, the incidence rates of tumor invasion into the medium-risk regions were mostly less than 10%, excluding the post-styloid compartment and oropharynx. According to the updated consensus guidelines of the neck node levels for head and neck tumors from 2013, level IIa (77.3%, 256/331), level IIb (75.8%, 251/331), and level VIIa (71.3%, 236/331) were the most frequently involved levels, followed by levels III (42.6%), Va (13.9%), IVa (8.8%), IVb (3.6%), Ib (3.6%), Vb (2.4%), VIIb (2.4%), VIII (1.8%), Vc (0.9%), and Xa (0.3%). Skip lymph node metastasis occurred in only 1.9% of patients.ConclusionsFor NPCs, primary disease and regional lymph node spread follow an orderly pattern, and a skip pattern of lymph node metastasis was unusual. Involved level radiotherapy might be feasible for cervical lymph node levels below the caudal border of cricoid cartilage and level VIIb.

Establishing an Endoscopic Chronic Subglottic Stenosis Rabbit Model.

To develop a reproducible and consistent chronic subglottic stenosis (SGS) in an endoscopic animal model. Prospective study. We conducted a prospective study using New Zealand white rabbits. Chronic SGS was induced endoscopically by Bugbee electrocautery to 50% to 75% of the subglottic area's circumference, followed by 4-hour endotracheal intubation. The rabbit airways were endoscopically assessed and sized with uncuffed endotracheal tubes (ETTs) before the injury, during follow-up, and at the endpoints. There were four endpoints: 2, 4, 6, and 8 weeks post SGS induction. Animals were humanely euthanized for histopathological examination of the subglottic injury site and microscopic measurement of the cricoid lumen. Twenty-two rabbits reached the endpoints, and 18 rabbits developed chronic SGS. ETT size significantly decreased by 0.5 from preinjury to the endpoint in all groups, P <.001. Control median cricoid lumen measurements were 20.48 mm2 , the median cricoid lumen measurement for the 2 weeks endpoint was 14.3 mm2 , 4 weeks 11.69 mm2 , 6 weeks 16.03 mm2 , and 8 weeks endpoint median was 16.33 mm2 . Histopathological examination showed chronic scar tissue and new cartilage formation at the cricoid level, mainly at the posterior subglottic injury site starting from 4 weeks postinjury. Collagen staining revealed substantial amounts of organized collagen and different collagen orientation starting 4 weeks postinjury lasting until 8 weeks postinjury. We developed an animal model to study chronic SGS. This model will be utilized to compare different endoscopic treatment interventions in acute SGS versus chronic SGS and further define the molecular basis of SGS. NA Laryngoscope, 132:1909-1915, 2022.

Influence of Different Measurements on the Ability of P-SAP and DES-OSA Scores to Detect Severe Obstructive Sleep Apnea.

Severe obstructive sleep apnea (sOSA) represents a risk factor of postoperative complications. Perioperative sleep apnea prediction (P-SAP) and DES-obstructive sleep apnea (DES-OSA) (DES being the acronym for 2 of the participating investigators and OSA for obstructive sleep apnea) scores were validated in the detection of such patients. They include the measurement of neck circumference (NC) and distance between thyroid and chin (DTC). The aim of this study was to evaluate the influence of the measurement method of NC and DTC on the ability of the 2 scores to detect sOSA. A total of 371 preoperative patients were enrolled. For each of them, 6 combinations of P-SAP and DES-OSA scores were evaluated. We compared the results of the 6 combinations with the data extracted from the polysomnography (PSG) if available. The ability of the score to detect sOSA patients was evaluated using sensitivity (Se), specificity (Sp), Youden index (YI), area under receiver operating characteristic curve (AUROC), the Probit model, and the Kappa coefficient of Cohen. A P < .05 was considered as significant, a Bonferroni correction was applied if needed. Three hundred and seventy-one patients had a PSG. The Se and the Sp of the DES-OSA score, and the Sp of the P-SAP score, in their ability to detect severe OSA patients, were influenced by the measurement method of the DTC and of the NC. Nevertheless, the AUROC, the Youden index, the Probit model, and the Kappa coefficient of Cohen are not influenced by the variability of measurement. This study highlights that the measurement method of NC and DTC can influence the results of the 2 scores. We conclude that a strict protocol for the measurement of NC and DTC should be applied (DTC measurement should be performed on a patient with a head in neutral position and the NC measurement should be performed at the cricoid level).

Extended Level IV Neck Dissection for Limited Prophylactic Clearance of Level V in Node-Positive Papillary Thyroid Carcinoma: a Homogenous Study Population.

There is near consensus that prophylactic lateral neck dissection has no role in the management of differentiated thyroid cancer, but the extent of lateral neck dissection in differentiated thyroid cancer remains controversial, especially whether level V should be addressed or not. There is lot of heterogeneity in reporting of the management of level V in papillary thyroid cancer. We at our Institute address the lateral neck positive papillary thyroid cancer with selective neck dissection involving levels II-IV, performing extended level IV dissection with inclusion of the triangular area delineated by the sternocleidomastoid muscle, the clavicle, and the perpendicular line drawn to the clavicle from the point where the horizontal line at the level of cricoid cuts the posterior border of sternocleidomastoid muscle. Retrospective analysis of the departmental data set related to thyroidectomy with lateral neck dissection from 2013 to mid-2019 for papillary thyroid cancer, was carried out. Patients with recurrent papillary thyroid cancer were excluded as were patients with involvement of level V. Data related to the demography of patients, histological diagnosis, and postoperative complications were compiled and summarized. Note was made of the incidence of ipsilateral neck recurrence and the neck level involved with recurrence noted. Data was analyzed for fifty-two patients of non-recurrent papillary thyroid cancer who had undergone total thyroidectomy and lateral neck dissection involving levels II-IV, with extended dissection at level IV. It should be noted that none of the patients had clinical involvement of level V. Only two patients had lateral neck recurrence, both the recurrences were in level III, one on the ipsilateral side and the other on the contralateral side. Recurrence in the central compartment was noted in two patients, with one of these patients also having ipsilateral level III recurrence. One of the patients had distal metastasis to the lungs. Transient paresis of the unilateral vocal cords was noted in seven patients which got resolved within 2months in all of them. Transient hypocalcemia was noted in four patients. Although our series has a small sample size with limited follow-up, it is one of the few studies in which prophylactic level V dissection has been studied in a homogenous study population of non-recurrent papillary thyroid cancer. Our study has shown that prophylactic dissection of level V may have a limited role, but further large multi-institutional studies need to be carried out to come up with a definite answer.

The Effect of Contralateral Head Rotation on Internal Jugular Vein to Carotid Artery Distance and Overlap Ratio

Introduction: Carotid artery puncture during central venous catheter (CVC) insertion could lead to serious complication if there were an overlapping of internal jugular vein (IJV) and carotid artery (CA). IJV and CA overlap ratio and distance were determined by contralateral head rotation angle. The optimal angle of contralateral head rotation during CVC insertion can decrease the risk of CA puncture complication. This study was aimed to investigate the optimal angle of contralateral head rotation on IJV to CA distance and overlap ratio at the cricoid level by ultrasound guidance. Methods: This was a cross-sectional study of 34 patients undergoing elective surgery with CVC insertion. IJV to CA distance and overlap ratio at the cricoid level on each subject in the supine position was measured by using two-dimensional ultrasound (Sonosite® M-Turbo, 6-13 MHz probe) at 0°, 30°, 45°, 60° contralateral head rotation of insertion site. Collected data were analyzed using SPSS 21.0. Results: There were significant differences on IJV to CA distance and overlap ratio at different contralateral rotation angles (0°, 30°, 45°, 60°, p<0.001). Overlapping of IJV and CA started to occur at contralateral head rotation 30° (11.72%) and increased in line with the increasing of contralateral head rotation angle (21.21% at 45°). Conclusion: There were significant effects of contralateral head rotation to distance and overlapping IJV to CA at the cricoid level. Optimal contralateral head rotation angle for CVC was less than 30° to prevent IJV and CA overlapping.

Tracheal Size and Morphology on the Reconstructed CT Imaging.

To characterize the real size and morphology of tracheas in childhood for the optimal selection of endotracheal tube. A retrospective cohort study of pediatric patients who received CT scan of the cervical spine from July 2011 to March 2018. Cross-sectional CT images vertical to trachea were reconstructed and the accurate tracheal diameters were measured. The validity of the traditional age-based formula for predicting the endotracheal tube size was assessed for the best fit to trachea. Tertiary Emergency and Critical Care Center of Kyushu University Hospital. Children, who are 1 month to 15 years old, received CT scan of the cervical spine. None. We enrolled 86 children with median age of 53 months. The cross-sectional shape of pediatric trachea was circular at the cricoid level and elliptical at the infraglottic level. The narrowest part of pediatric trachea was the transverse diameter at the infraglottic level at any age. Significant positive correlation between age and the narrowest diameter was observed. When compared the transverse diameter at the infraglottic level with the outer diameter of endotracheal tubes, uncuffed endotracheal tubes selection based on the traditional age-based formula ran a significant risk of oversized endotracheal intubation until 10 years old compared with cuffed endotracheal tubes selection (60.0% vs 23.8%; p < 0.05). These findings indicate the safety and efficacy of cuffed endotracheal tubes in infants and children and the reconsideration for the airway management in pediatric anesthesia and intensive care.

Position and relative size of the vertebral artery according to age: Implications for internal jugular vein access.

The purpose of this retrospective observational study was to investigate the anatomical characteristics of the vertebral artery in pediatric patients using computed tomography images. We evaluated anatomical characteristics of the right and left vertebral artery at the cricoid level and at a lower level, which was mid-level between the cricoid cartilage and the origin of vertebral artery from the subclavian artery. At each level, the cross-sectional areas of the vertebral artery and internal jugular vein, the relative size of vertebral artery to internal jugular vein, the minimum distance between them, and the extent of overlap between them were investigated. According to the chest computed tomography images of 344 patients, the sizes of internal jugular vein and vertebral artery were found to increase with age. On the other hand, the relative size of the vertebral artery to internal jugular vein was found to increase conversely with decreasing age. The distance between the vertebral artery and internal jugular vein increased with age at both sides and levels. The vertebral artery was mostly located at the medial side of the internal jugular vein, and overlapped with the internal jugular vein in at least 54% of the patients at the cricoid level and in 74% at the lower level. The theoretical risk of vertebral artery puncture is higher in younger children during internal jugular vein catheterization.

Upper airway in infants-a computed tomography-based analysis.

Recent studies suggest that the pediatric airway is elliptical with the subglottis rather than the cricoid as the narrowest part contrary to the old belief of a funnel-shaped airway. The shape of the airway in neonates and infants has not been studied separately. This study seeks to define the shape of the upper airway in neonates and infants, and determine if there are differences in airway shape between infants and older children. We studied 40 computed tomographic scans of children from birth to 12 months of age undergoing radiological evaluation unrelated to airway symptomatology. The computed tomographic scans were obtained during either natural sleep or with sedation and spontaneous ventilation without airway devices in place. Transverse and anteroposterior diameters were measured at the subglottic level and at the cricoid ring. The mean age was 5.9 ± 3.4 months. The mean transverse and anteroposterior diameters were 5.3 ± 0.83 mm and 7.2 ± 0.89 mm at the subglottic region and 6.1 ± 0.86 mm and 6.7 ± 0.79 mm at the cricoid level. An increase in the transverse dimension of the airway was observed from the subglottic region to the cricoid ring. Although the anteroposterior dimension decreased from the subglottis to the cricoid ring, the airway remained wider in the anteroposterior dimension compared to the transverse dimension from the subglottis to the cricoid ring. The present study demonstrates that the airway in neonates and infants between the subglottic area and the cricoid remains elliptical. The cricoid is not round as has been observed in older children. The airway is wider anteroposteriorly and narrows in the transverse dimension from the subglottis to the cricoid in infants.

Ultrasonographic Measurement of Subglottic Diameter for Paediatric Cuffed Endotracheal Tube Size Selection: Feasibility Report.

The aim of this feasibility study was to investigate the first attempt success of ultrasonography (USG) in paediatric patients in predicting an appropriate cuffed endotracheal tube (ETT) size. Fifty children who were 1-10 years of age and who received general anaesthesia with endotracheal intubation for adenoidectomy or adenotonsillectomy were enrolled in the study. In all participants, the transverse diameter of the subglottic airway was measured with USG at the cricoid level without ventilation. The outer diameter (OD) of the maximum allowable ETT was chosen according to the measured subglottic airway diameter. In the presence of resistance to passage of the tube into the trachea or in the absence of an audible leak at airway pressure of >25 cm H2O, the ETT was replaced with a tube whose internal diameter (ID) was 0.5 mm smaller. If a leak was audible at airway pressures of <10 cm H2O, if a seal could not be achieved with a cuff pressure of >25 cm H2O or if a peak airway pressure of >25 cm H2O was observed during ventilation, the tube was changed to a tube one size larger. The OD of the best-fit ETT was converted to the ID. The best-fit ID, the requirement for ETT replacement, the duration of airway diameter measurement by USG and the peak airway pressure were recorded. The success rate of the first attempt with USG was 86%; the ETT was replaced in five patients with a tube one size larger and in two patients with a tube one size smaller. Our findings show the subglottic diameter measured by USG to be a reliable predictor in estimating the appropriate paediatric ETT size.

Difficulty in inserting left double-lumen endobronchial tubes at the cricoid level in small-statured women: A retrospective study.

Background and Aims:Left double-lumen endobronchial tube (DLT) sizes are selected using tracheal diameters and left mainstem bronchial diameters (LMBDs) determined from chest radiographs or computed tomography (CT) scans. In Western women, 35-Fr or 37-Fr DLTs are often selected. However, difficulties can be encountered when inserting 32-Fr or 35-Fr DLTs in Japanese women. We investigated success rates for 32-Fr or 35-Fr DLT insertion in Japanese women and determined the causes of unsuccessful DLT insertion.Methods:We searched anaesthesia records of Japanese women aged ≥20 years who underwent thoracic surgery with 32-Fr or 35-Fr DLTs between April 2010 and March 2015 in our hospital. In the successful group (SG), patients were intubated using the initially selected DLTs. By contrast, in the unsuccessful group (UG), the DLT size had to be changed. The Mann–Whitney U-test and Fisher's exact test were used to compare groups.Results:The SG included 149 (96.1%) of 155 cases of 32-Fr DLT use and 119 (95.2%) of 125 cases of 35-Fr DLT use. Patient height was significantly lower in the UG than in the SG for the 35-Fr DLT (P = 0.0036). In seven of 12 UG patients (three for 32-Fr and four for 35-Fr), the transverse diameters of cricoid cartilages were smaller than the DLTs' tracheal diameters, thereby preventing passage through the cricoid cartilages.Conclusion:Along with LMBDs, transverse diameters of cricoid cartilages based on CT scans or ultrasonogram findings may help in selecting the appropriate left DLT size.

Idiopathic laryngotracheal stenosis.

Idiopathic laryngotracheal stenosis (ILTS) is a rare inflammatory disease of unknown etiology. Infectious, traumatic and immunologic processes must first be excluded. The majority of patients affected are female who present with progressive symptoms of upper airway obstruction, which can extend over a number of years. ILTS is characterized by short segment, circumferential stenotic lesions, located particularly at the level of the cricoid. Bronchoscopic evaluation is essential for establishing the diagnosis and operative planning. Various temporizing interventions have historically been utilized, including dilation and laser ablation, for symptomatic management. However these interventions have demonstrated diminishing returns and poor long-term outcomes. Patients with ILTS should be considered early for definitive surgical intervention to minimize complications and optimize outcomes. Laryngotracheal resection and reconstruction is a viable intervention, which has demonstrated good long-term results and low recurrence rates for this patient population.

Helical computed tomography scanning of the larynx and upper trachea in rabbits.

BackgroundComputed tomography (CT) is used to evaluate the human tracheobronchial tree because of its unsurpassed ability to visualize the airway and surrounding structures. To establish an ideal animal model for studying subglottic stenosis, we assessed the size and morphology of the normal rabbit’s laryngotracheal airway by helical CT. We measured luminal dimensions at the levels of the arytenoid and cricoid cartilages and the first, third, and eighth tracheal rings. At all levels, the axial slices were used to calculate the maximum anteroposterior (AP) dimension, transverse dimension, and cross-sectional areas. We measured the tracheal length from the cricoid to the third and eighth tracheal rings on sagittal reformation. We assessed the hyoid, thyroid, cricoid, arytenoid, and tracheal rings for the presence of calcific or soft tissue densities. We also addressed the presence or absence of pre-epiglottic and paraglottic fat.ResultsThe mean AP tracheal dimension ± standard deviation (SD) was 8.6 ± 0.5 mm at the arytenoid level, 8.2 ± 0.7 mm at the cricoid level, and 7.7 ± 0.2 mm at the first tracheal ring level. The transverse tracheal dimension ±SD was 5.3 ± 0.1 mm at the arytenoid level, 5.5 ± 0.5 mm at the cricoid level, and 6.1 ± 0.6 mm at the first tracheal ring level. The mean tracheal area ±SD was 35.7 ± 2.2 mm2 at the arytenoid level, 35.8 ± 5.1 mm2 at the cricoid level, and 39.2 ± 4.3 mm2 at the first tracheal ring level. The tracheal length ±SD was 10.7 ± 2.3 mm from the cricoid to the third tracheal ring and 19.1 ± 1.14 mm to the eighth tracheal ring. There was complete calcification of the hyoid in all rabbits. Only two rabbits showed complete thyroid, arytenoid, or tracheal ring calcification. The remaining airway components were otherwise either uncalcified or partially calcified. The uvula, epiglottis, aryepiglottic fold, vallecula, piriform sinus, true/false vocal cords, and pre-epiglottic/paraglottic fat were not seen in any rabbit.ConclusionsHelical CT investigation provides good, highly definitive anatomic details of the larynx and trachea in rabbits. Such results may be used in further evaluation of the normal airway and in cases of subglottic stenosis.

Subjective neck pain or foreign body sensation and the true location of foreign bodies in the pharynx

Conclusion: The location of the foreign body did not correspond well to the location of pain reported by patients. When patients present with foreign bodies in the pharynx, in addition to recording the location of pain and foreign body sensation, clinicians should perform a comprehensive and thorough oropharyngeal examination to avoid misdiagnosis. Objectives: Physicians are often guided by patient-indicated locations of pharyngeal foreign bodies. In this study, we aimed to determine the correlation between the location of the subjective neck pain or foreign body sensation and the true location of the foreign body. Methods: We prospectively studied 90 patients who had pharyngeal foreign bodies removed at MacKay Memorial Hospital. We divided the head and neck into 10 zones according to the superficial anatomy. Subjective location, examination findings, and actual foreign body location were recorded and compared. Results: The overall subjective and true locations of the foreign body were poorly correlated (kappa 0.27, p = 0.003). The positive predictive value (PPV) for the midline neck was 68%, which was higher than that on either lateral side of the neck. PPV above cricoid cartilage level was 66%.

Intaoperative neuromonitoring in thyroid surgery

Thyroid surgery is most frequent interventions on endocrine organs. Whereas laryngeal nerves which inner vate the muscles of larynx are passing nearby the thyroid and central compartment therefore the risk of their injury and functional integrity is extremely important. First of all it is recurrent laryngeal nerve which in 0.5–2.7% has not “recurrent” path and depart vagus at cricoid cartilage level. Secondary it is external branch of superior laryngeal nerve with innervates cricothyroid muscle. Routine use of intraoperative neuromonitoring significantly decrease laryngeal nerves temporary palsy (paresis) rate however significant reduction of perma nent palsy frequency was not demonstrated in most published papers. At the same time all authors accept that intraoperative neuromonitoring undoubtedly facilitate detection of laryngeal nerves and allow to convince their functional capacity. Taking into account that safety is a paradigm of contemporary endocrine surgery the intra operative neuromonitoring going towards further investigation and improvement.