Comparative Study between two Ultrasound Aided Methods in PreoperativeAssessment of Difficult Airway in Obese Patients

Background Unpredictable difficult laryngoscopy remains a challenge for anaesthesiologists, especially if difficult ventilation occurs. So, accurate airway assessment should always be performed so as to provide appropriate planning and management of expected difficult intubation and to limit any unexpected difficulties. Airway assessment using ultrasound has been proposed recently as a useful, simple and non-invasive bed side tool as an adjunct to clinical methods. Objective To establish whether correlations existed between two ultrasound measurements and the Cormack–Lehane grade during direct laryngoscopy, and whether these measurements are useful in predicting are stricted or difficult view especially in morbid obese individuals. The first is the measurement of the hyomental distance of the patient in neutral position of the neck and in fully extended neck calculating the ratio between both of them. While the second is the measurement of anterior cervical soft tissue thickness at three anatomical levels (hyoid bone, thyrohyoid membrane or ‘pre epiglottic space’ and anterior commissure). We chose these two new measurements from among the various ultrasound assessments made in previous studies because of their simplicity of execution in normal clinical and in emergency settings. Patients and Methods The current study is a prospective comparative clinical trial of assessment of difficult air way using two different ultrasound aided techniques in comparison to Cormack and lehane scoring system. Those patients were chosen upon some inclusion and exclusion criteria; inclusion criteria were (Age of the patient (25-60y), ASA I-II patients, Obese patients with body mass index > 30 kg /m2 and Pts undergoing bariatric surgery) and exclusion criteria were (Pathology of the airway (tumors), Deformity of the airway anatomy (burns, scars), History of facial, cervical, pharyngeal and epiglottis surgery or trauma, Patients with most teeth lost and Patient refusal). Results Regarding U/S measurements in method A patients; the average HMD-neutral of A patients was (53.58±5.33) mm, the average HMD-extension was (58±7.82) mm, and the average HMDR was (1.07±0.06). It showed highly significant decrease in HMD extension and HMDR in difficult group, compared to easy group, in A group of patients (p < 0.01respectively). Non-significant difference as regards HMD-neutral U/S measurements in method A (p > 0.05). Conclusion Ultrasonography can be a valuable adjunct in this aspect of airway assessment. Ultrasound assessment of pre-epiglottic tissue thickness at the level of the thyrohyoid membrane may be useful to predict restricted/difficult direct laryngoscopy and difficult intubation. The ratio of hyomental distance between neutral and extended positions may also be a good predictor of difficult direct laryngoscopy.

Surface Electromyography for Identification of Pre-Phonatory Activity

Surface electrode EMG is an established method for studying biomechanical activity. It has not been well studied in detecting laryngeal biomechanical activity of pre-phonatory onset. Our aims were to compare the sensitivity of surface EMG in identifying pre-phonatory laryngeal activity to needle electrode laryngeal EMG and to compare the pre-phonatory period in patients with adductor laryngeal dystonia (ADLD) with that in controls. ADLD patients (n = 10) undergoing needle LEMG prior to Botox injection and participants with normal voices (n = 6) were recruited. Surface EMG electrodes were placed over the cricoid ring and thyrohyoid membrane. Needle EMG electrodes were inserted into the thyroarytenoid muscle. EMG and auditory output samples were collected during phonation onset. Tracings were de-identified and evaluated. Measurements of time from onset in change of the amplitude and motor unit frequency on the interference pattern to onset of phonation were calculated by two blinded raters. 42 of 71 patient and 40 of 50 control tracings were available for analysis. Correlation for pre-phonatory time between electrode configuration was 0.70 for patients, 0.64 for controls and 0.79 for all the data combined. Inter-rater correlation was 0.97 for needle and 0.96 for surface electrodes. ADLD patients had a longer pre-phonatory time than control subjects by 169.48ms with surface electrode and 140.23ms with needle electrode (p < 0.001). Surface EMG demonstrates equal reliability as Needle EMG in detecting pre-phonatory activity in controls and subjects. Patients with ADLD have a significantly prolonged pre-phonatory period when compared with controls.

The Superior Laryngeal Nerve and Its Vulnerability in Surgeries of the Neck

Anatomical considerations of the superior laryngeal nerve (SLN), a branch of the vagus, provides information to minimize the potential for iatrogenic intraoperative injury, thereby preventing motor and sensory dysfunctions of the larynx. The present study aims to assess the variation of the SLN and its relationship to the superior thyroid artery (STA) and superior laryngeal artery (SLA). The study was done on 35 formalin-fixed cadavers at Oakland University in 2018–2019. In our study, we found that out of 21 cadavers, 52.4% of the external laryngeal branches (ebSLN) are related posteromedial to the STA, while 47.6% are related anteromedial to it. Out of 14 cadavers, 64.3% of the internal laryngeal branches (ibSLN) are related superoposterior to the SLA, while 35.7% are inferoposterior to it. In most cases, the SLA crosses above the ebSLN while traveling to pierce the thyrohyoid membrane to reach the larynx. The data demonstrate that both the ebSLN and ibSLN display variation in their relationship with the STA and the SLA, respectively. Awareness of these variable relationships is critical for identification and isolation of these structures in order to prevent consequences of nerve injury, primarily a reduction in the highest attainable frequency of the voice and aspiration pneumonia.

Early Internal Branch of Superior Laryngeal Nerve Bifurcation Passes Through Double Thyroid Foramen

Internal branch of superior laryngeal nerve (ibSLN) provides sensory innervation mostly to the supraglottic part of the larynx and thus prevents aspiration during ingestion. Normally, it is distributed to the larynx after piercing the thyrohyoid membrane above the superior laryngeal artery. Multiple anatomical variations in the course of ibSLN have been reported. An early ibSLN bifurcation and course through double thyroid foramen constitutes an interesting anatomical variation that may easily lead to an injury during procedures in the thyroid gland and the larynx. Knowledge of the anatomical variability is essential in order to prevent surgical complications that could potentially impact the patient’s quality of life.

Infrahyoid thyroglossal cyst and Neck trauma - A diagnostic conundrum

Thyroglossal duct cysts are most commonly located inferior to the hyoid bone in close relation with the thyrohyoid membrane. Very rarely, they may occupy the posterior hyoid space, and present with dysphagia. We present the clinical, pathophysiologic features and the iintraoperative findings of thisrarely described clinical entity

Laryngeal oncocytic cystadenoma mimicking a combined laryngomucocele

Laryngeal oncocytic cystadenomas are rare benign tumours lined by oncocytic epithelium and arising from the salivary glands; they usually present as a supraglottic mass. Oncocytic changes are very uncommon in the larynx and occur mainly in ventricles and false vocal cords, where seromucinous glands predominate. The authors present the case of a 62-year-old woman who reported a 6-month history of hoarseness associated with a soft and non-compressible upper left side neck swelling. Transnasal fiberoptic laryngoscopy revealed a left submucosal supraglottic mass involving the false vocal fold and the vallecula, partially obstructing the airway. CT scan showed a homogeneous isodense cystic lesion centred at the left laryngeal ventricle, with extension through the thyrohyoid membrane. The patient was successfully managed by a lateral thyrotomy approach. Histopathological examination of the specimen revealed a papillary oncocytic cystadenoma and excluded malignancy. There was no evidence of recurrence after 9 months of follow-up.

Imaging of Pharyngocele: An Occupational Overuse Syndrome

Pharyngocele is a rare pathology of the pharynx caused by the laxity of the thyrohyoid membrane. Only about 60 true lateral pharyngocele cases have been reported in the literature over the last 133 years. Laryngocele is a close differential, and the two are difficult to tell apart. Though they have been described well in the literature, they are often misdiagnosed or interchangeably diagnosed. The acquired type of pharyngocele is due to prolonged increased intrapharyngeal pressure and pharyngeal wall weakness, and it is more common than congenital pharyngoceles. Close differential diagnoses include Zenker’s diverticulum, laryngocele, and jugular venous phlebectasia. Acquired lateral pharyngoceles are seen in wind instrument musicians and glassblowers. Hence, these diverticula are described as ‘overuse syndrome’. We present a case of bilateral neck swelling, which occurred doing the Valsalva maneuver with imaging studies.

Morphometric Determination of Sex of Hyoid Bone

Background and Objectives The hyoid bone shows sexually dimorphic features, which could be used in the sex determination aspect of establishing the biological profile in the remains of skeleton. The aim of this study was to investigate morphometrical variations of the hyoid bone in South Indian population. Materials and Methods A total of 60 adult larynx specimens (30 male and 30 female) with attached hyoid bone were dissected out from postmortem cadavers. The infrahyoid muscles and thyrohyoid membrane were removed. Hyoid bone was dissected and dried completely. Total 10 measurements like length of each greater cornua, length of body, major transverse axis, total hyoid length on both the sides, breadth of hyoid, and height of body of hyoid were taken on each hyoid bone using a digital Vernier caliper. Results The range, mean, standard deviation, and level of significance of all 10 parameters of hyoid bone were calculated using standard statistical method. Most of the parameters showed significant difference between the values of male and female hyoid bones. Conclusion Values obtained for all 10 parameters of hyoid bone were higher in males compared with females, which is suggestive that male hyoid bones are larger in size compared with female hyoid bones.

A case of third branchial cleft cyst

Branchial cyst or congenital cystic lesions of neck originate from branchial clefts, the 2nd branchial cleft cyst being the most common and 3rd and 4th being missed. Hence, they are often misdiagnosed as lymph nodal masses, cold abscess. We are reporting a case of 3rd Branchial cleft cyst, of a 12-year-old boy who presented with left sided recurrent painful cystic mass at the level of hyoid bone going down to the level of pyriform fossa. All the tests for tuberculosis were negative. USG neck revealed loculated thick walled cyst from SCM to lateral part of pharynx. CECT revealed a thick-walled cyst extending from the anterior border of the sternocleidomastoid going down obliquely below the level of thyrohyoid membrane to pyriform fossa. Exploration revealed a thick walled infected cyst, pushing left upper pole of thyroid medially and anterior to left sided superior laryngeal nerve. The cyst was going downwards medially below the level of thyrohyoid membrane. The cyst was excised completely. Histopathology revealed the findings of squamous epithelial lining of cyst wall and cholesterol crystals within. Detailed anatomy on CECT, surgery and histopathology confirmed 3rd arch Branchial cyst.