Superior Laryngeal Artery Research Articles

English

The variations in the distribution pattern of superior thyroid artery are of great importance for head and neck surgeons because of its vital relationship to the external laryngeal nerve. In this case an unusual unilateral variation in the arterial supply of thyroid gland was found during routine dissection of an elderly male cadaver in the Department of Anatomy, GGS Medical College, Faridkot, Punjab. The left superior thyroid artery took origin from the anterior aspect of left common carotid artery and it exhibited a usual relationship with the left external laryngeal nerve. The inferior thyroid arteries did not show any unusual distribution. Knowledge of such arterial variations related to the thyroid gland is immensely helpful for surgeons in order to put ligature on anomalous artery and to avoid damage to vital structures in this area. It is also helpful to the INTRODUCTION: The Superior Thyroid Artery (STA) is the main source of arterial blood to the thyroid gland, upper part of the larynx and neck region. It is a branch of external carotid artery (ECA) and arises from its anterior surface, just below the level of greater cornu of the hyoid bone. It runs downwards from its origin and gives a branch i.e. superior laryngeal artery (SLA) which pierces the thyrohyoid membrane along with the internal laryngeal nerve. It also gives an infrahyoid branch, a branch to the sternocleidomastoid muscle and a crico-thyroid branch. 1 The relationship of the superior thyroid artery to the external laryngeal nerve is important to the surgeon during thyroid surgery. The artery and nerve are close to each other higher up but diverge near the gland. Thus in order to avoid injury to the external laryngeal nerve, the superior thyroid artery is ligated as near to the gland as possible. The STA is frequently used as a recipient vessel for microvascular free tissue transfer in head and neck surgery, for selective embolization of thyroid and head and neck tumors, and as a landmark for identifying the external laryngeal nerve in thyroid surgery. 2 Surgical procedures involving the thyroid gland require a thorough knowledge not only of the normal gross anatomy of the structures within the region but also of the anatomical variations of the structures located within it. Thyroid surgery being a major surgery and quite often performed, a thorough knowledge of variations in arterial supply is very essential for surgeons to prevent alarming number of table deaths in patients with thyroid disease due to excessive and uncontrollable bleeding. It is also of help to the radiologists and physicians for proper physical examination and treatment of the patient and to the anatomists for learning the variant patterns.

Superselective intra-arterial chemoradiation therapy for functional laryngeal preservation in advanced squamous cell carcinoma of the glottic larynx

Conclusion: Superselective intra-arterial chemotherapy is a safe and useful treatment that preserves the vocal, swallowing, and feeding functions of the larynx in T3 cancer supplied by the superior laryngeal artery and T4a cancer not extending beyond the thyroid cartilage. Objective: To evaluate the outcomes of superselective intra-arterial chemotherapy for squamous cell carcinoma of the glottic larynx. Methods: Sixty-four patients with squamous cell carcinoma of the glottic larynx underwent treatment of the primary tumor using induction chemotherapy with two cycles of intra-arterial docetaxel and cisplatin, plus continuous intravenous infusion of 5-fluorouracil for 120 h starting on day 2; followed by two cycles of concurrent chemoradiation therapy. Residual neck lymph node metastases were treated by neck dissection. Results: The overall 5- and 10-year survival rates were 70.4% and 62.9%, respectively. The 5- and 10-year survival rates were 96.3% and 89.9%, respectively, in the 29 patients with T3 cancer, and 50.4% and 44.1%, respectively, in the 35 patients with T4a cancer. The overall 5- and 10-year laryngeal preservation rates were 71.0% and 60.6%, respectively. The 5- and 10-year laryngeal preservation rates were 92.5% and 87.4%, respectively, in patients with T3 cancer, and 48.6% and 35.6%, respectively in patients with T4a cancer. No irreversible adverse effects were reported.

Proposal of landmarks for clamping neurovascular elements during endoscopic surgery of the supraglottic region

Bleeding within the supraglottic region can be a lethal complication after CO(2) laser microsurgery. Our aim was to propose endoluminal anatomical landmarks to locate the superior laryngeal vessels resulting in a safer microsurgery. Endoluminal dissections were made in 22 larynges without laryngeal disease. The neurovascular structures were in the superior third of a triangle defined by the vocal process, the anterior commissure, and the epiglottic attachment of the aryepiglottic fold. They overlapped in 4 different ways: pattern I (70.4%): superior laryngeal vein (SLV), superior laryngeal artery (SLA), and internal laryngeal nerve (ILN); pattern II (13.6%): SLA, SLV, ILN; pattern III (4.6%): SLV, ILN, and SLA; pattern IV (4.6%): SLA, ILN, and SLV. Microsurgery in the supraglottic region may be safer if surgeons are aware of the superior third of the above-defined triangle, "danger area", where the vascular elements of this region are located.

Variant origins of arteries in the carotid triangle - A case report

The left superior laryngeal artery was observed arising from the external carotid artery instead of the superior thyroid artery in the cadaver of an approximately 70 year-old Asian man. In addition, on the same side, the superior thyroid artery arose from the common carotid artery 2 cm before the bifurcation instead of its usual origin from the external carotid artery. From the external carotid artery, the lingual and facial arteries arose from the common linguofacial trunk. The nerves in the carotid triangle were normal in course. No variations were observed on the right side carotid system. The multiple variations in this case have not been previously described. The embryogenesis of this combination of variations is not clear, but the anatomic consequences may have important clinical implications. As angiography has gained popularity in diagnostic approaches in recent years, it is essential to be aware of these variations so that they are not overlooked in differential diagnoses.

Clinically Relevant Anatomy of High Anterior Cervical Approach

An anatomic study of anterior cervical dissection of 11 embalmed cadavers and measurement of structures relative to cervical spine. To determine the anatomic relationship of the hypoglossal nerve (HN), internal and external superior laryngeal nerves (ESLNs), superior thyroid artery (STA), and superior laryngeal artery (SLA) to cervical spine and demonstrate any vulnerability. The anterior approach is a common approach to the cervical spine. Much of the operative morbidity in high cervical region is related to neurovascular injury leading to dysphagia, dysphonia, impaired high-pitch phonation, and impaired cough reflex. Eleven adult cadavers (5 male/6 female) were dissected bilaterally to expose structures of the high anterior cervical region. The HN consistently traveled toward the midline at C2-3 and was safe caudal to C3-4. In 95% of dissections, the internal superior laryngeal nerve (ISLN) was exposed within 1 cm of C3-4. The path of the ESLN was variable, but it was safe above C3-4 and below C6-7. The ESLN was deep to the STA, and it was less bulky and tauter than the ISLN in all dissections. The origin of the STA was quite variable along the carotid artery, but it was most commonly located at C4. Two anatomic variants of the SLA were observed. In 15 dissections, the SLA branched off the superior thyroid. In six dissections, the SLA branched directly from external carotid artery. There was no appreciable side-to-side variation in the neurovascular structures studied. On the basis this study, spine surgeons can have enhanced knowledge of high anterior cervical anatomy. The neurovascular structures in this study did not demonstrate side-to-side anatomic variation; therefore, patient pathology and surgeon preference should dictate the operative side.

Classification System for Lateral Pharyngotomy

Objective: 1) Propose a classification system of lateral pharyngotomy (LP) used in exposing various sites of the oropharynx, supraglottis, and hypopharynx. 2) Describe the structures visible with each category of lateral pharyngotomy. Method: An anatomic study on 5 fresh-frozen human cadavers was carried out at the Medical Education and Research Institute. After exposure of the anterior compartment of the neck and laryngeal framework, progressively more extensive pharyngotomy was performed. The pharyngeal structures exposed with each extension were recorded by video and still photography. Results: Entry into the pharynx between the hypoglossal nerve cephalically and the superior laryngeal nerve caudally (Type I LP) provided exposure of the epiglottis and ipsilateral tongue. Exposure toward the pyriform apex was facilitated by dividing the superior laryngeal artery (Type II LP). This provided exposure to the postcricoid area, arytenoids, and cervical esophageal inlet. The digastric and stylohyoid muscles were transected (Type III LP) to provide exposure of the entire base of tongue, uvula, and soft palate. Division of the hyoglossus and mylohyoid muscles was classified as Type IV LP, adding visualization of the vallecula and contralateral tonsil. Conclusion: An appropriate class of pharyngotomy may be chosen depending on the structures requiring exposure. This cadaver-based anatomic study delineated the anatomic structures to be divided to facilitate exposure of pharyngeal subsets. A classification system is proposed that defines the steps in gaining access to the pharynx.

Topographic anatomy of the internal laryngeal nerve: Surgical considerations

This study is focused on the topographic features of the internal branch of the superior laryngeal nerve (ibSLN) at the thyrohyoid membrane area using as anatomic landmarks the posterior border of the thyrohyoid muscle and the superior border of the thyroid cartilage. Thirty-six fresh adult cadavers were dissected to determine the topography and branching pattern of the ibSLN and the superior laryngeal artery. The ibSLN prior to thyrohyoid membrane's penetration was divided into 3 or 2 branches, in 72.22% and 27.78% of cases. The trifurcated ibSLN was more common than the bifurcated in both sexes and in both sides of the neck. In over 80% of cases the ibSLN penetrated the thyrohyoid membrane 0.1 to 0.9 cm far from the posterior border of the thyrohyoid muscle and 0.1 to 1.2 cm far from the superior border of the thyroid cartilage. We provide a schematic overview of the ibSLN penetration zone at the thyrohyoid membrane, the so-called danger zone, to avoid ibSLN damage.

Unusual Origin of the Arteries in the Carotid Triangle of the Neck: A Case Report and Literature Review

Though the variations in the carotid arteries and their branches are common in the carotid triangle, it is important for the clinicians, surgeons and the radiologists to be aware of all possible variations of these arteries. A case of abnormal origin of 2 important arteries encountered during routine dissection of carotid triangle of the neck is reported. The superior thyroid artery that normally originates form the external carotid was seen to originate from the common carotid artery and the superior laryngeal artery was arising from the external carotid artery instead of the superior thyroid artery. Further, a detailed literature review was done and the surgical, radiological and clinical importance of the case was discussed.

Anatomical variations of the superior thyroid and superior laryngeal arteries

There are known to be variations in the origins of the superior thyroid artery (STA), an important surgical landmark, and 1 of its branches, the superior laryngeal artery (SLA). Three hundred thirty human embalmed heminecks were dissected. The results of previous studies were reviewed, and a meta-analysis is presented. Four different origins for the STA were found. The most frequent was type I, from the carotid bifurcation (49%). Four different origins were also found for the SLA being the most frequent the type I in which the artery arose from STA (78%). The mean external diameters of STA and SLA were 0.26 and 0.20 cm, respectively, with no statistically significant differences by side or sex. Variations in the origin of STA and SLA from the carotid arterial tree and the similarity of their diameters mean that there is a significant possibility of their misidentified during surgery.

Angiographic Study of the Superior Laryngeal Artery

The study goals were to demonstrate the superior laryngeal artery in detail with angiograms and to understand its vasculature three-dimensionally. Three fresh cadavers were totally injected with lead oxide-gelatin mixture. The larynx with the surrounding tissue was resected and radiographed stereoscopically with soft X ray system. We get informed consent from a person in question and the bereaved family. The superior laryngeal artery was divided into the ascending and descending branches. The ascending branch supplied the epiglottis chiefly from the ventral surface, and anastomosed with branches of the lingual artery. The descending branch supplied the vestibular and vocal folds, muscles of the larynx and mucosa over the muscles, and anastomosed with distal branches of the superior thyroid artery. Stereographic angiograms and macroscopic observation enabled us to understand vasculature of the superior laryngeal artery.

Clinically relevant variations of the superior thyroid artery: an anatomic guide for surgical neck dissection

The superior thyroid artery (STA) is the dominant arterial supply of the thyroid gland, upper larynx and the neck region. The knowledge of variations in possible patterns of origin, courses, and branching pattern of the STA is also important for surgical procedures in the neck region, such as emergency cricothyroidotomy, radical neck dissection, catheterization, reconstruction of aneurysm and carotid endarterectomy. The surgical anatomy of the STA was studied in 20 adult Anatolian preserved cadavers between the age of 40 and 70 years. The outer diameter of the STA origin was observed to be 3.53 +/- 1.17 mm. The location of the origin of the STA according to the carotid bifurcation was evaluated as above (25%), below (35%) and at the same level (40%). The distribution patterns of the STA were classified into six types depending on the branching pattern. The outer diameter of the infrahyoid branch, superior laryngeal artery, sternocleidomastoid artery and cricothyroid branch at their origins were observed to be 1.13 +/- 0.14, 1.42 +/- 0.47, 1.54 +/- 0.96 and 1.30 +/- 0.41 mm, respectively. Typical and variant glandular branching patterns were observed in 85 and 15% of the specimens, respectively. The outer diameters of anterior, anteromedial, anterolateral and posterior glandular branches were measured as 2.05 +/- 0.46, 1.41 +/- 0.43, 1.51 +/- 0.41 and 1.73 +/- 0.53 mm, respectively. It is necessary to understand the surgical anatomy of the STA to carry out successful radical neck dissection and to minimize postoperative complications in a bloodless surgical field.

Postoperative bleeding in transoral laser microsurgery for upper aerodigestive tract tumors

To report the incidence, cause, and outcome of bleeding after transoral laser microsurgery. A two-center prospective case series analysis. Seven hundred one patients underwent transoral laser microsurgery for tumors of the oral cavity, pharynx, and larynx from June 1996 through September 2006. Ten patients (1.4%) experienced postoperative bleeding between 0 and 17 days after surgery. Five patients had previously untreated tumors, and five patients had salvage surgery. Two patients (0.3%) had minor bleeding and required observation only. Five patients (0.7%) experienced major bleeding requiring exploration under general anesthesia. Three patients (0.4%) had catastrophic life-threatening bleeds, two of whom died. The bleeding vessel was identified as the lingual artery in four patients, the superior laryngeal artery in two, the facial artery in two, and unknown in two. Bleeding after transoral laser microsurgery is rare but potentially life-threatening.

Neurovascular variations in the carotid triangle

Anatomical variations in the carotid triangle of the neck may present importance especially during surgical and radiological interventions of the region. We found two variations in the left carotid triangle of an adult female during routine dissection classes. There were two superior laryngeal arteries, one originated from the superior thyroid artery and another abnormal superior laryngeal artery originated directly from the external carotid artery. There was a hole in the internal jugular vein and the accessory nerve passed out through the hole.

The morphology and topography of the superior laryngeal artery

The aim of this study was to investigate and correlate the anatomical parameters of the superior laryngeal artery (SLA). For the study, 50 adult, human specimens were used; laryngeal pieces were drawn from 16 cadavers and the arteries were dissected intralaryngeally. In 68%, the SLA originated from the superior thyroid artery and in 32%, directly from the external carotid artery. In five sides, an aberrant superior laryngeal artery (ASLA) was entering the larynx through a foramen thyroideum. The normal superior laryngeal artery (NSLA) had a short extralaryngeal part and continued intralaryngeally, with two segments and a point of inflexion; the first segment ran along the superior border of the thyroid cartilage, the point of inflexion of the NSLA was at a minimal distance of 1.1 cm anterior to the superior horn of the thyroid cartilage and from this point the NSLA continued in the paraglottic space. The ASLA had a constant origin from the superior thyroid artery; it then traversed the foramen thyroideum and reached the paraglottic space-at the superior border of the lateral cricoarytenoid muscle, it ended in two terminal branches. We constantly evidenced the following collateral branches of the NSLA: superior, anterior and postero-medial. The terminal branches are the antero-inferior branches that constantly anastomose with the cricothyroid artery and the postero-inferior branch anastomosed with the inferior laryngeal artery. Occasionally, additional branches of the NSLA were found. In conclusion, the intralaryngeal branching patterns of the NSLA and the ASLA are similar, the differences being given by the entry point into the larynx that will make the superior and anterior branches of the ASLA longer, will eliminate the transversal segment of the NSLA, and will shorten the descending segment in the paraglottic space in the case of ASLA. The base of the upper horn of the thyroid cartilage, the oblique line and its tubercles, the cricothyroid membrane and the cricothyroid joint are constant landmarks that allow a precise intralaryngeal identification of the SLA. These findings can improve performances during surgical manipulations of the larynx and laryngeal transplants.

Aberrant branch of the superior laryngeal artery passing through the thyroid foramen

This study examines the microsurgical anatomy of the aberrant superior laryngeal artery (ASLA) which passes through the thyroid foramen. It defines the location of the ASLA and its main branches. The aberrant superior thyroid artery was looked for in 20 randomly selected Chinese adult cadavers, and when found, was dissected and measured under an operating microscope (7-30x magnification). The ASLA passed through the thyroid foramen, which only occurred in the presence of the artery. The foramen was observed in six of the 20 cadavers: one on the right, three on the left, and two on both sides. The study provides detailed information concerning the ASLA, which we hope will help explain the arterial bleeding that may occur during laryngeal surgery. The results might be helpful in improving surgery to the larynx and other neck operations. Incidental intraoperative injury of the aberrant artery could be avoided by understanding details of its course in relation to surrounding anatomic landmarks.

Feeding Artery of Laryngeal and Hypopharyngeal Cancers: Role of the Superior Thyroid Artery in Superselective Intraarterial Chemotherapy

The purpose of this study was to elucidate the role of the superior thyroid artery in intra-arterial infusion chemotherapy for laryngeal and hypopharyngeal cancers. Thirty-nine patients with laryngeal cancer and 29 patients with hypopharyngeal cancer underwent intra-arterial infusion chemotherapy. We performed a retrospective analysis of the feeding arteries confirmed by computed tomography during selective arteriography and compared the results with the extent of the tumors. In 14 of 39 laryngeal and 15 of 29 hypopharyngeal cancers, the tumor did not cross the midline (group 1). In the remaining 25 and 14 cancers, respectively, the tumor crossed the midline or located in the center (group 2). For 13 of 14 laryngeal and 7 of 15 hypopharyngeal cancers in group 1 and for 6 of 25 laryngeal cancers in group 2, the entire tumor was contrast enhanced by the ipsilateral superior thyroid and/or superior laryngeal artery. For 12 of 25 laryngeal and 1 of 14 hypopharyngeal cancers in group 2, the entire tumor was contrast enhanced by the bilateral superior thyroid artery. For the other patients, infusion via the other arterial branches such as the inferior thyroid and the lingual arteries were needed to achieve contrast enhancement of the entire tumor. Superselective intra-arterial chemotherapy for laryngeal cancer from the superior thyroid artery is appropriate, whereas that for hypopharyngeal cancer is less sufficient. To accomplish contrast enhancement of the entire tumor, additional intra-arterial infusion from other arteries such as the inferior thyroid artery is often necessary.

Surgical anatomy of the internal branch of the superior laryngeal nerve

The internal branch of the superior laryngeal nerve (ibSLN) may be injured during anterior approaches to the cervical spine, resulting in loss of laryngeal cough reflex, and, in turn, the risk of aspiration pneumonia. Such a risk dictates the knowledge regarding anatomical details of this nerve. In this study, 24 ibSLN of 12 formaldehyde fixed adult male cadavers were used. Linear and angular parameters were measured using a Vernier caliper, with a sensitivity of 0.1 mm, and a 1 degrees goniometer. The diameter and the length of the ibSLN were measured as 2.1+/-0.2 mm and 57.2+/-7.7 mm, respectively. The ibSLN originates from the vagus nerve at the C1 level in 5 cases (20.83%), at the C2 level in 14 cases (58.34%), and at the C2-3 intervertebral disc level in 5 cases (20.83%) of the specimens. The distance between the origin of ibSLN and the bifurcation of carotid artery was 35.2+/-12.9 mm. The distance between the ibSLN and midline was 24.2+/-3.3 mm, 20.2+/-3.6 mm, and 15.9+/-4.3 mm at the level of C2-3, C3-4, and at the C4-5 intervertebral disc level, respectively. The angles of ibSLN were mean 19.6+/-2.6 degrees medially with sagittal plane, and 23.6+/-2.6 degrees anteriorly with coronal plane. At the area between the thyroid cartilage and the hyoid bone the ibSLN is the only nerve which traverses lateral to medial. It is accompanied by the superior laryngeal artery, a branch of the superior thyroid artery. The ibSLN is under the risk of injury as a result of cutting or compression of the blades of the retractor at this level. The morphometric data regarding the ibSLN, information regarding the distances between the nerve, and the other consistent structures may help us identify this nerve, and to avoid the nerve injury.

Anatomical Study of Meandering and Functions of Human Intralaryngeal Artery

In recent years, partial laryngectomy and partial reconstruction are increasingly intended for conservation of functions of phonation and swallowing. In partial reconstruction, it is important to comprehend morphological characteristics of the blood vessels distributed in the larynx, but there have been only few reports discussing detailed information about them. Previous reports on laryngeal blood vessels have shown that branches of some arteries show remarkable "meandering". In the present study, we devised a method for objectively determining the morphological nature, "meandering" and assessed functions of the arteries. Intralaryngeal arteries were excised from the larynx of cadavers prepared for practice in anatomy, and images of the "meandering" artery were analyzed with NIH Image. The extent of "meandering" was expressed mainly as the ratio of the total length of the blood vessel to the distance between the starting point and the end point of meandering. The results showed that there was a significant difference in the extent of meandering between superior posterior and medial posterior branches of superior laryngeal artery. These arteries, which were distributed in the arytenoid region, were found to be of primary importance in partial laryngectomy and partial reconstruction of the larynx.

Anatomic Considerations of Superior Laryngeal Nerve During Anterior Cervical Spine Procedures

Cadavers were dissected anatomically to identify the course of the superior laryngeal nerve relative to the spinal column. To illustrate the anatomic relation of the SLN with respect to its vulnerability during anterior cervical spine procedures. There is ample literature referencing the superior laryngeal nerve with respect to head and neck surgery. Detailed descriptions of the anatomy of the recurrent laryngeal nerve are quite extensive in both the spine and head and neck literature. To the authors' best knowledge, no similar reports have delineated the anatomic relation of the superior laryngeal nerve in procedures on the anterior aspect of the cervical spine. Ten dissections were carried out on human cadavers to show the course of the superior laryngeal nerve. Particular attention was directed to the internal branch of the superior laryngeal nerve to show the overall anatomic relation relative to standard landmarks. These landmarks included the superior laryngeal and superior thyroid arteries, the split of the superior laryngeal nerve, and the intervertebral disc space. The superior laryngeal nerve originates from the vagus nerve in the carotid sheath and bifurcates into internal and external branches. Distally, the internal branch of the superior laryngeal nerve courses in close proximity with the superior laryngeal artery and inserts within 1 cm superior to the superior laryngeal artery into the thyrohyoid membrane. With respect to the cervical spine, the distal of portion of the internal branch of the superior laryngeal nerve is located between the C3 and C4 vertebral bodies. The internal branch of the superior laryngeal nerve supplies innervation to the mucosa of the larynx and has an important sensory reflex that serves to protect the lungs from aspiration. Injury to this nerve can predispose the patient to life-threatening pneumonia. It is therefore imperative for the surgeon to recognize the location and course of this nerve to avoid injuring it. Injury most commonly occurs either by excessive retraction in different planes or by accidental ligation of the nerve.

Microsurgical anatomy of the laryngeal nerves as related to thyroid surgery.

The objectives were to explore microsurgical anatomy of the superior and recurrent laryngeal nerves and their importance in thyroid surgery, and to examine areas of potential morbidity, means of identification, and arterial supply of the laryngeal nerves. Descriptive analysis of anatomical features. Twenty-one adult cadavers, some perfused with colored silicon, were dissected for the study project. The right recurrent laryngeal nerve (RLN) branches off the vagus at the level of the subclavian artery and the left one at the level of the aorta. Both ascend parallel to the tracheoesophageal groove and innervate trachea, esophagus, and the inferior pharyngeal constrictors en route. The RLN has the highest probability to pass between the branches of the inferior thyroid artery on the right side and posterior to them on the left side. The RLN always passes posterior to the cricothyroid joint. The RLN is supplied by the branches of the inferior thyroid artery. The superior laryngeal nerve (SLN) branches into internal and external branches deep to the carotid bifurcation. The internal branch passes deep to the superior thyroid artery and descends toward thyrohyoid membrane. The external branch travels deep and parallel to the superior thyroid artery to innervate cricothyroid muscle. The internal branch is supplied by the superior laryngeal artery, and the external branch by the cricothyroid artery. The only consistent location of the RLN is when it passes posterior to the cricothyroid joint. Because of extreme variability of the inferior thyroid artery and the RLN, it is suggested that the artery be ligated either proximally or at its tertiary branches on thyroid capsule. The internal branch of the SLN is not potentially at risk during thyroidectomy unless the superior thyroid artery is ligated proximally. The external branch of the SLN accompanies the superior thyroid artery for most of its course and is at potential risk if the trunk of the superior thyroid artery is ligated outside the pretracheal fascia.