A rare case of abnormally high thoracic duct in neck

Thoracic duct injury can be a cause of significant morbidity if its injury remain undiagnosed during surgery. Knowledge of its course and anomaly should be known to prevent its injury. Presenting a case of 40 year male who was diagnosed to have left buccal mucosa squamous cell carcinoma. During neck dissection, anomalous thoracic duct was found much above the omohyoid muscle. Adequate steps were taken to prevent injury to it. It is necessary to acknowledge thoracic duct and prevent its injury during neck dissection. Knowledge about its anomalous path should be known to prevent its injury. Valsalva manoeuvre should be done at the end of neck dissection to find and thoracic duct injury by observing chyle leak and adequate measures should be taken immediately to prevent morbidity associated with it.

Cadaveric study investigating the phrenic-sparing volume for anterior suprascapular nerve block

BackgroundThis cadaveric study investigated the maximum effective volume of dye in 90% of cases (MEV90), required to stain the suprascapular nerve while sparing the phrenic nerve during the performance of an anterior suprascapular nerve block.MethodsIn cadaveric neck specimens, using ultrasound guidance, the block needle was advanced until its tip was positioned underneath the omohyoid muscle next to the suprascapular nerve. The dye was injected in order to achieve circumferential spread around the latter. Successful phrenic-sparing suprascapular nerve block was defined as the non-staining of the phrenic nerve on dissection. Volume assignment was carried out using a Biased Coin Design, whereby the volume of dye administered to each cadaveric specimen depended on the response of the previous one. In case of failure (ie, stained phrenic nerve), the next one received a lower volume (defined as the previous volume with a decrement of 2 mL). If the previous cadaveric specimen had a successful block (ie, non-stained phrenic nerve), the next one was randomized to a higher volume (defined as the previous volume with an increment of 2 mL), with a probability of b=0.11, or the same volume, with a probability of 1 – b=0.89.ResultsThirty-one cadavers (56 cadaveric neck specimens) were included in the study. Using isotonic regression and bootstrap CI, the MEV90 for phrenic-sparing anterior suprascapular nerve block was estimated to be 4.2 mL (95% CI 3.0 to 5.0 mL). The probability of a successful response was estimated to be 0.90 (95% CI 0.84 to 0.96).ConclusionFor ultrasound-guided anterior suprascapular nerve block, the MEV90 of dye required to spare the phrenic nerve is 4.2 mL. Further studies are required to correlate this finding with the MEV90 of local anesthetic in live subjects.

A Systematic Review of the Omohyoid Muscle Syndrome (OMS): Clinical Presentation, Diagnosis, and Treatment Options

Objective: Omohyoid muscle syndrome (OMS) is a condition that causes a X-shaped lateral neck lump on swallowing, caused by the failure of the central tendon of the omohyoid muscle to restrict movement of the muscle during swallowing. We aim to review the etiology, pathophysiology, diagnostic tests, and management options for this condition. Data Sources: Pubmed, MEDLINE, EMBASE, and Cochrane databases were searched for all articles and abstracts related to OMS up to 29th July 2020. Review Methods: A systematic review was performed, data extracted from relevant full text articles. Both quantitative data and qualitative data were analyzed. Results: Twenty cases of OMS were reported. Patients presented at a mean age of 36.0. All cases were Asian. There is a 7:3 ratio of males to females. The most common symptom was a transient neck mass. Most cases were managed conservatively with good prognosis. Open or endoscopic transection of the muscle and ultrasound-guided botulinum toxin injection were 3 treatment options, with no recurrence at 4 years, 6 months, and 6 months respectively. Conclusion: OMS could be genetic as all cases were Asian in ethnicity. The deep cervical fascia which usually envelopes the omohyoid muscle may be weakened by stress as 20% of cases had a preceding traumatic event. Real-time ultrasonography establishes the diagnosis, demonstrating the anterolateral displacement of the sternocleidomastoid muscle by a thickened omohyoid muscle during swallowing. Surgical transection can achieve cure, but due to limited studies available, they should be reserved for patients who are extremely bothered. Intramuscular injection of botulinum toxin is an effective alternative, but recurrence is expected.

PEQULIARITIES OF MORPHOGENESYS AND TOPOGRAPHY OF INFRAHYOID TRIANGLES IN HUMAN PREFETUSES AND FETUSES

The aim: To investigate morphology and developmental features of anatomical structures in the infrahyoid triangles of human neck during prefetal and fetal periods of human ontogenesis. Materials and methods: We have studied 30 specimens of human prefetuses from 7th till 12th week (16,0-82,0 mm of parieto-coccygeal length (PCL)) and 30 human fetuses aged from 4th till 10th month (84,0-360,0 mm PCL) of intrauterine development by the means of macro-, microscopy, morphometry, three-dimensional remodeling and statistical analyses. Results: We can observe anterior triangle in human fetuses after the time when common precursor muscular mass splits into two: the anterior and posterior portions which will give rise to the sternocleidomastoid and trapezoid muscles accordingly. The area index of the central triangle in human fetuses 4th – 10th month of intrauterine development shows the increasing tendency with the highest rates at 8th–10th months period – 1100-1200 mm2. The angulated course of omohyoid muscle is visible at late prefetal and early fetal periods (3-4th month; 80,0-130,0 PCL) as well as the presence of intermediate tendon. Peaks of the area of sternocleidomastoid region area evaluation was observed in 190,0-210,0 mm PCL and 260,0-270,0 mm PCL human fetuses; 6th and 7,5th months accordingly. Conclusions: The critical periods for the AT and SCM regions should be considered 6th and 8th months of the IUD. Prefetal period shows the presence of AT and border structure for the IH neck – precursor of HB. Fetal period of IUD (4th – 10th months of IUD) should be considered as such that represents an adult-alike morphology of IH neck: presence of IH triangles with fully developed vascular, muscular and fascial content.

Association of Tortuous Common Carotid Artery with Abnormal Distribution of the Ansa Cervicalis: A Case Report

In the current study, we display a rare association of an aberrant innervation of the sternocleidomastoid muscle by the ansa cervicalis (AC) with a tortuous common carotid artery (TCCA). In specific, in a male cadaver we observed on the right side of the cervical region, a nerval branch of remarkable size originating from the most distal part of the AC’s superior root and after piercing the superior belly of the omohyoid muscle innervated the distal portion of the sternocleidomastoid muscle. Furthermore, we noticed a tortuous course of the initial part of the right common carotid artery. We discuss the surgical significance of the awareness of AC’s variations during neurotisation of the recurrent laryngeal nerve in cases of its damage, as well as the importance of aberrant innervation of the sternocleidomastoid muscle by AC for the preservation of muscle’s functionality after accessory nerve’s damage. Furthermore, we highlight the fact, that the knowledge of the relatively uncommon variant, such as TCCA is crucial for the physician in order to proceed more effectively in differential diagnosis of a palpable mass of the anterior cervical region or deal with symptoms such as dyspnea, dysphagia or symptoms of cerebrovascular insufficiency.

Omohyoid muscle syndrome

Omohyoid muscle syndrome is a rare cause of a bulging lateral neck mass that occurs on swallowing that often a worrisome observation because of the concern of malignancy and cosmetic deformity. The first case has been documented on 1969. A 12 years old male came to Surgical Oncology Outpatient Clinic with chief complaint a protruding right lateral neck mass during swallowing. He noticed this complaint since three months prior. He had no previous history of medical illness. He had history of multiple chokehold trauma when playing with his friend 6 months ago. He had no symptoms besides the mass occurring on his right neck. The patient went through the cervical radiograph and neck ultrasonography examination. There were inconclusive results. The patient was informed that the implication of these findings was strictly cosmetic and did not pose any risk of long-term consequence. Corrective cosmetic surgery was recommended as an option if he was concerned about the cosmetic appearance and conservative management was recommended to observe any pain or dysphagia he might experience in the near future. He denied surgery and did not seek further care for his condition. Omohyoid muscle syndrome is a rare condition that might occur after trauma such as chokehold to the neck. Imaging on this syndrome quite challenging especially when there were no other symptoms experienced. If it is proven to be strictly cosmetic, most patients will choose to have a conservative therapy.

Ultrasound appearance of peripheral nerves in the neck: vagus, hypoglossal and greater auricular

Background and aim. Information in ultrasonography about reference values of nerves, particularly of those located in the neck is limited. The aim of the study is to demonstrate the feasibility of direct visualization of the vagus, hypoglossal and greater auricular nerves, testing the method on healthy volunteers and estimate the reference values for two perpendicular diameters and cross-sectional area (CSA). Methods. A prospective study was carried out on 21 healthy volunteers (12 women and 9 men), recording their demographic characteristics. A 13 MHz transducer was used on a Hitachi EUB-8500 machine. The vagus nerve was measured at the bifurcation of common carotid artery (CCA) and at the intersection of the internal jugular vein with omohyoid muscle. The hypoglossal nerve was identified as it crosses the posterolateral border of the mylohyoid muscle in the submandibular space. The auricular nerve was identified on the superficial surface of the sternocleidomastoid muscle at 1 cm from its posterior margin. The mean CSA on axial scans, nerve width and thickness were determined. The side-to-side and gender differences of the estimated reference values and their correlations with the weight, height, and body mass index (BMI) were evaluated. Results. The mean ultrasound-estimated CSA was measured for the vagus nerve at CCA bifurcation (2.14 ± 0.79 on the left 2.86 ± 1.27 on the right), vagus nerve at the level of omohyoid muscle (2.10 ± 0.06 on the left and 2.43 ± 0.08 on the right), hypoglossal nerve (1.71 ± 0.08 on the left, 1.24 ± 0.06 on the right) and greater auricular nerve (0.90 ± 0.53 on the left and 0.79 ± 0.71 on the right). The vagus nerve was significantly larger on the right side compared to the left side. Larger hypoglossal nerve was observed in men compared to women. Significant correlations were observed between weight and CSA of the greater auricular nerve. Conclusion. Direct visualization of the vagus, greater auricular nerve and hypoglossal nerves is feasible. Reference values for the size of the studied nerves at specific anatomic landmarks were established. Side, gender and body weight differences of the nerves CSA were noted.