Contrast-enhanced computed tomography of retromandibular vein position and course patterns relative to the mandible during sagittal split ramus osteotomy.

Background: Sagittal split ramus osteotomy is an established procedure used in oral and maxillofacial surgery. Major bleeding is representative intraoperative complication involves vessels such as the inferior alveolar, facial, and maxillary arteries and accompanying veins, in particular the retromandibular vein (RMV). We previously described the RMV course patterns using embalmed cadavers. However, owing to the possible influence of formalin fixation and unclear skeletal classification of the jaws, the present study aimed to use contrast-enhanced computed tomography to confirm the RMV in patients with defined jaw deformities. Methods: Twenty patients with orthognathic jaw deformities (40 sides) were included. The RMV and the lateral and posterior views of the mandible were evaluated using contrast-enhanced computed tomography. Course patterns and RMV positions were classified as previously reported. Results: Three patterns were identified in the lateral view. Type A: RMV posterior to the posterior border of the ramus (n=25; 62.5%). Type B: adjoining the posterior border of the ramus (n=12; 30.0%). Type C: anterior to the posterior border of the ramus (n=3; 7.5%). Five course patterns were identified in the posterior view. Pattern I: rectilinear course running medial to the posterior border of the ramus (n=3; 7.5%). Pattern II: diagonal course running medially from immediately posterior to posterior border of the ramus (n=11; 27.5%). Pattern III: rectilinear course running immediately posterior to the posterior border of the ramus (n=12; 30.0%). Pattern IV: diagonal course running from lateral to medial relative to the posterior border of the ramus (n=8; 20.0%). Pattern V: diagonal course running from lateral to immediately posterior relative to the posterior border of the ramus (n=6; 15.0%). In the no-course pattern group, the RMV inferior to the lingula was lateral to its position and superior to that of the lingula. In half of the cases, the left and right sides exhibited different running patterns. We observed no correlation between the skeletal patterns of jaw deformities and the course of the RMV. Conclusions: Type B/Pattern II that runs in a straight line bordering the posterior margin of the ramus requires the most attention during surgery. These findings suggest the possibility of predicting intraoperative bleeding risk.

Retromandibular Vein, Digastric Muscle, and Greater Auricular Nerve in Superficial Parotidectomies for Patients with Pleomorphic Adenoma-A Surgical Experience.

Retromandibular vein (RMV) and posterior belly of digastric muscle are among the landmarks used to identify facial nerve in parotid surgery. This observational cross-sectional study was done in the Department of ENT &HNS at a tertiary care teaching hospital for a period of 8 years with the aim to aware young otorhinolaryngologist about the relationship of posterior belly of digastric muscle & retromandibular vein with facial nerve and share our experience about preservation of posterior branch of greater auricular nerve. A total of 34 cases of superficial parotidectomies done for pleomorphic adenoma were included in this study. Relationship of facial nerve with retromandibular vein and posterior belly of digastric muscle was noted. Greater auricular nerve was identified, and every attempt was made to preserve its posterior branch. Retromandibular vein was medial to the trunks of facial nerve in 33 (97%) patients. It was lateral to lower division and medial to upper division in one case. Greater auricular nerve was seen to bifurcate into two branches (Anterior and posterior) in 21 (62%) cases while in one case(3%) three branches were seen emerging from main trunk and in another case(3%) first two branches were seen emerging and then anterior branch was further dividing into two. Preservation of posterior branch of greater auricular nerve was possible in 23 (68%) of patients. Posterior belly of digastric muscle was seen as a reliable and constant landmark. Facial nerve was seen superior to upper border of posterior belly of digastric muscle in all cases (100%). No anatomical variation of posterior belly was seen. Retromandibular vein is invariably seen medial to the trunks of facial nerve. Facial nerve is always seen superior to upper border of posterior belly of digastric muscle in almost all cases. Preservation of posterior branch of greater auricular nerve is possible in majority of the cases.

Extracapsular Dissection of Deep Lobe Parotid Mass Aided by Retromandibular Vein on Imaging: A Case Report.

This report investigates the use of the retromandibular vein on imaging as a diagnostic tool for planning deep lobe parotid tumors. A unique aspect of this case is the performance of extracapsular dissection on a deep lobe parotid lesion, which is rare. Preoperative imaging showed a superficially displaced retromandibular vein, indicating a deeply seated tumor, which aided surgical planning. Under general anesthesia, extracapsular dissection was performed while protecting the facial nerve branches. The patient's postoperative course was uneventful, and the facial nerve was intact with no weakness.

Variation in the formation of the retromandibular and the external jugular veins with embryological overview: A case report.

Awareness of the formation and termination of the head & neck's superficial vein, such as jugular veins, are imperative for anatomists, surgeons, and radiologists during interventional procedures. We report an uncommon variation in the formation of the retromandibular vein and external jugular vein (EJV) in an embalmed male cadaver's right side. The joining of the facial vein and superficial temporal vein within the parotid gland formed the retromandibular vein (RMV). The anterior division joined with the submental vein forming an anomalous venous trunk. The anomalous vein united with the EJV forming a common trunk in the lower third of the neck and terminated into the subclavian vein. We compared the available literature and justified the embryological development of this rare variation.

A Rare Case of a Fenestrated Retromandibular Vein Lying Lateral to the Facial Nerve Bifurcation.

Facial nerve integrity is the cornerstone of parotid surgery. Although a variety of anatomical landmarks have been employed, facial nerve injury still happens causing devastating functional and cosmetic sequelae. The retromandibular vein is considered one of the most consistent structures lying just deep into the facial nerve. In our cadaveric study, we found a fenestrated retromandibular vein lying superficial to the bifurcation of the facial nerve. This rare anatomical variation would have been a challenge for a hypothetic parotidectomy. Surgeons should be aware of both anterograde and retrograde dissection of the facial nerve and choose the most proper approach to preserve the integrity of the facial nerve.

Retromandibular vein ectasia : A parotid mass mimicker.

Retromandibular venous ectasia is a rare lesion that may imitate a parotid gland mass. Accurate radiological diagnosis prevents unnecessary invasive procedures. We present the case of a 69-year-old male patient presenting a right-sided, painless, compressible parotid region mass, fluctuating in size with head position and Valsalva maneuver. No thrill was palpable on physical examination. Doppler ultrasound demonstrated an anechoic compressible intra-parotid lesion, with luminal color filling, and venous spectral waveform. Contrast-enhanced computed tomography and Magnetic resonance angiography of the neck revealed an ectatic retromandibular vein. The patient was conservatively managed and regularly followed up. No complications occurred. Cervical region venous ectasias are rare and commonly misdiagnosed. They should be considered in the soft neck masses differential diagnosis. Imaging plays a key diagnostic role.

Unusual Relation of Facial Nerve and Retromandibular Vein in Parotid Surgeries: a Case Series.

The relation between the facial nerve and the retromandibular vein is of paramount clinical significance during the parotid surgery for the protection of all the facial nerve branches as these two anatomic structures are always in close proximity. However, variations in the relationship of the facial nerve with the retromandibular vein, as presented in this paper complicate parotid surgery and increase the potentiality of unexpected bleeding and injury to the facial nerve injury. This study was conducted in a tertiary care teaching hospital. 4 cases with unusual relation of facial nerve and retromandibular vein in parotid surgeries were studied & included in this study. Out of 70 parotid surgeries which were performed, 4 variations of the retromandibular vein in relation to facial nerve were encountered. With a meticulous dissection the facial nerve branches were separated from the retromandibular vein without causing any injury to the neurovascular structures and functional deficit. Knowledge of normal anatomy of the extra cranial facial nerve and its relation with the retromandibular vein along with the probable anatomical variations leads to a safe parotid surgery.

Comparative Study of Morphology and Distribution of Valves in Human Retromandibular Vein.

The objective of this study was to analyze the distribution and morphology of the valves in the human retromandibular vein. The retromandibular, internal thoracic, azygos, femoral, and brachial veins were harvested from 46 cadavers donated to the Department of Anatomy at Tokyo Dental College for dissection. The frequency of the valves in each vein, the length of the cusps, and the thickness of the vein itself were measured. Valves were present at high frequency (92.1%) in the veins of the limbs and had cusps at least twice as long as the internal diameter of the vein. Veins in the trunk contained a lower frequency of valves, with cusps that tended to be shorter (1.60±0.77) than those of the venous valves in the limbs (2.12±0.60). The valves of the retromandibular vein tended to resemble venous valves in the trunk in terms of both frequency and morphology. The main function of venous valves in the limbs is to prevent retrograde flow. Conversely, valves in the veins of the trunk and retromandibular vein play a role in retaining blood in the veins, and their relationship to other veins means that they can cause major hemorrhage.

Retromandibular vein position and course patterns in relation to mandible: anatomical morphologies requiring particular vigilance during sagittal split ramus osteotomy.

Major bleeding associated with sagittal split ramus osteotomy (SSRO) involves vessels such as the inferior alveolar, facial, and maxillary arteries and veins, and the retromandibular vein (RMV). The present study aimed to clarify and classify the three-dimensional variations in RMV position and course direction in relation to the mandible. Specimens comprised a total of 15 scientific cadavers, and the relationship between RMV and the mandible lateral and posterior views was observed. We identified 3 patterns on the lateral view, the mean distance between the RMV and the posterior border of the ramus was 3.9 mm at the height of the lingula. A total of five course patterns were identified on the posterior view. In no course pattern, the RMV inferior to the lingula was lateral to its position superior to the lingual. The present findings suggest that it may be possible to predict correlations with intraoperative bleeding risk. Further study is planned using contrast computed tomography in patients with jaw deformity for skeletal classification.

Unilateral external jugular vein fenestration with variant anatomy of the retromandibular and facial vein.

External jugular vein (EJV), a significant superficial vein draining head and neck (H&N) region is been increasingly used for cannulation in diverse diagnostic purposes and intravenous therapies. The variant anatomy of formation and draining patterns of EJV and retromandibular veins were reported earlier. In the present case, EJV showed significant variation in one of the male cadaver, during routine H&N dissection. On the left side, a fenestration of EJV was observed and the transverse cutaneous nerve of the neck was passing through the fenestration of the vein. Anatomical knowledge of EJV and retromandibular vein variations as found in this case is important for surgeons performing microvascular surgeries in H&N and also to the radiologists during their conventional radiological procedures like angioplasty, catheterization, and at times of hemodialysis in case of renal failure patients.

Características de las venas pericondíleas de la articulación temporomandibular en la celda parotídea / Characteristics of the pericondylar veins of the temporomandibular joint in the parotid cell

Introducción: La presencia de la vena pericondílea en la zona de la articulación temporomandibular es escasamente reportado en la literatura, sin embargo se encuentra presente en los preparados anatómicos disecados, y durante los procedimientos quirúrgicos. Objetivo: Determinar las características de la vena pericondílea ubicada en la zona de la articulación temporomandibular, relacionadas con la región parotídea. Material y Métodos: Se diseñó un estudio transversal, prospectivo que incluyó 30 cadáveres humanos que fueron diseccionados a nivel de la articulación temporomandibular. Se analizó las variables de distribución de la vena pericondílea, forma, dimensiones y relaciones con las estructuras adyacentes. Resultados: Los 30 casos presentaron la vena pericondílea que rodeó la cara externa del cuello del cóndilo mandibular. El 73,3 por ciento de venas desembocó a nivel de la vena retromandibular. El 38,3 por ciento de venas presentaron trayecto oblicuo. La longitud promedio fue de 2,37 cm y su diámetro promedio de 1,82 mm. Entre las relaciones, se encontró la presencia de la arteria pericondílea en dos casos. Conclusiones: La vena pericondílea estuvo presente en todos los casos en su mayoría única y localizada rodeando por fuera el cuello del cóndilo mandibular; desemboca con mayor frecuencia en la vena retromandibular y hasta su desembocadura presenta frecuentemente trayecto oblicuo, de arriba hacia abajo y hacia atrás(AU)

Introduction: The presence of the pericondylar vein in the area of the temporomandibular joint is scarcely reported in the literature; however, it is present in anatomical dissected preparations and during surgical procedures. Objective: To determine the characteristics of the pericondylar vein located in the area of the temporomandibular joint, related to the parotid region. Material and Methods: A cross-sectional, prospective study that included 30 human cadavers that were dissected at the temporomandibular joint level was conducted. The variables analyzed were the distribution of the pericondylar vein, its shape, dimensions and the relationships existing between bony structures. Results: The 30 cases presented the pericondylar vein that surrounded the external face of the neck of the mandibular condyle; 73,3 percent of the veins ended at the level of the retromandibular vein; 38,3 percent of them presented an oblique path. The average length of the vein was 2,37 cm and its average diameter was 1.82 mm. The presence of the pericondyleal artery was found in two cases, among other relationships. Conclusions: The pericondyleal vein was present in all cases, mostly unique and located around the outside of the neck of the mandibular condyle. It most frequently runs into the retromandibular vein. Up to its mouth, it often has an oblique path, from top to bottom and backwards(AU)

Unusual and multiple variations of head and neck veins: a case report.

We report an unusual and multiple variation involving the right head and neck veins which were found during routine dissection in a 50-year-old male cadaver, facial vein draining into both external and internal jugular veins, fenestration in external jugular vein transmitting the supraclavicular nerve trunk, the anterior division of the retromandibular vein draining into anterior jugular vein and the absence of the common facial vein. The knowledge about these variations is important during various surgical and diagnostic procedures involving head and neck region.

Anatomical Characteristics of Facial Nerve Trunk in Vietnamese Adult Cadavers.

BACKGROUND: In medical literature, there are few studies provided a precise and detailed description of the facial nerve rami and its branches. AIM: Identify several practical anatomic landmarks related to the facial nerve main trunk and its rami. METHODS: A descriptive study, 30 cadavers in the anatomy department of UPNT from October 2012 to April 2015. RESULTS: The average distance from the mandibular angle to the division of the facial nerve is 40.8 mm, and is 86.6% from range 36 - 50 mm. There is 86.7% case in which the facial nerve is in the lateral of the retromandibular vein, and there is a significant difference about both sides. Eighty percent of the case has the superior and inferior ramus in the lateral to the retromandibular vein. There are 2 cases in which the superior ramus makes the circle of the vein. Eighty percent of the facial nerve is in the lateral to the external carotid artery. CONCLUSION: The distance from the mandibular to the division of the facial nerve is longer. The relationship between the superior/inferior ramus and the retromandibular vein maybe not the same in both sides. In some cases, it makes the circle of the vein to cause some complication in the parotid gland surgery.

Variations of Retromandibular Vein and Its Relation to Facial Nerve Within Parotid Gland.

Maxillary vein and superficial temporal vein unite to form the retromandibular vein in the parotid gland. The facial nerve lies lateral to external carotid artery and retromandibular vein. Identifying and preserving the facial nerve is the prime motto during parotidectomy. So the variations of facial nerve and the retromandibular vein should be known so as to avoid injury to both. The variations we encountered during parotid surgery will be helpful in avoiding unexpected bleeding and injury to facial nerve.

Novel variations in spatial relations between the facial nerve and superficial temporal and maxillary veins.

Variations in the relationship of the retromandibular vein to the facial nerve have been widely reported due to their relevance for surgical approaches in parotid, osteotomy and mandibular condyle surgery. In the context of the retromandibular retroparotid approach, remaining deep to the retromandibular vein is advised to decrease the likelihood of encountering the facial nerve during mandibular condyle surgery. In the present report, an unusual variant of the superficial temporal vein lying superficial to the facial nerve is described. This represents a variation of the venous branching pattern within the parotid gland, whereby the superficial temporal vein joins the maxillary vein inferior to its usual communication. These findings are discussed in the context of commonly used surgical approaches to the mandible for condylar trauma or osteotomy surgery.

The multiplanar analysis of the retromandibular vein in surgical planning for parotid gland tumors.

OBJECTIVE: To analyze the effectiveness of the multiplanar analysis of the retromandibular vein in establishing the position of the parotid gland tumor and its relationship with the facial nerve, together with the most common radiological criteria (facial nerve line, Utrecht line, retromandibular vein and parapharyngeal space variations) using the magnetic resonance imaging. STUDY DESIGN: Retrospective study SETTING: Tertiary Academic Hospital SUBJECTS AND METHODS: 128 preoperative magnetic resonances were analyzed to study preoperative tumor location (medial or lateral to the expected course of the facial nerve) based on comparison between the radiological criteria and the surgical findings. RESULTS: FN line had the lowest accuracy at 77%, whereas the retromandibular vein achieved 85% accuracy and the UT line achieved accuracy of 93%. The retromandibular vein could not be identified in 11 cases (9%). The multiplanar evaluation of the retromandibular vein allowed us to identify it on almost all MR images (99% of cases) and reach 87% of accuracy. The parapharyngeal space evaluation achieved 92% of accuracy. In the subgroup of 66 cases where the neoplasms were strictly related to the main trunk, where the surgery entailed manipulation if situated laterally to the tumor, the multiplanar evaluation of the retromandibular vein reached 98% of accuracy and UT line achieved 94%. CONCLUSIONS: The multiplanar modality, combined with the evaluation of the parapharyngeal space, is effective in helping the surgeon to achieve accurate planning: it enables the tumor to be located and the facial nerve course predicted with a good precision.

Anatomic variation of the relation between the facial nerve and the retromandibular vein during superficial parotidectomy: A rare case report.

INTRODUCTION: Identification and preservation of the facial nerve (FN) is a major challenge when performing parotidectomy. Anatomic variations of the relation between the FN and the retromandibular vein (RMV) pose a high risk of nerve injury and bleeding during the operation. PRESENTATION OF CASE: An unusual anatomic variation of the relation between the FN and the RMV was unexpectedly detected during superficial parotidectomy. The operation was uneventful. A meticulous review of the recent literature was conducted as well. DISCUSSION: Variations of the relation between the FN and the RMV are mainly identified during the operation, since when performing parotidectomy, surgeons typically detect all the FN branches by locating the RMV. Such kind of variations, are not as rare as considered and their presence complicates parotid surgery and increases the potentiality of nerve injury and hemorrhage. CONCLUSION: Surgeons' deep knowledge and perpetual awareness concerning the probable anatomic variations of the relation between the FN and the RMV combined with detailed exposure of the operative field and of the relationship between these adjacent anatomical structures lead to safe parotid surgery.

Variaciones anatómicas en el drenaje venoso del cuello / Anatomical variations in the venous drainage of the neck

Resumen Las venas superficiales, especialmente la vena yugular externa, son cada vez más utilizadas para canalización o procedimientos diagnósticos, terapias intravenosas, nutrición parenteral en pacientes debilitados. Las variaciones en el drenaje venoso de la cabeza y cuello son importantes no solamente para los anatomistas y radiólogos, sino también para los cirujanos. Durante una disección de rutina en el Laboratorio de Morfología de la Universidad de Pamplona en un cadáver masculino de 75 años de edad, se encontraron variaciones anatómicas e inusuales patrones de drenaje en la región de cara y cuello, las cuales fueron cuidadosamente disecadas y los detalles morfológicos fueron fotografiados; esas variaciones consistían en: ausencia unilateral de vena yugular externa. La vena lingual, la vena infrahioidea y la vena tiroidea superior tenían conexiones venosas transversas que drenaban en un arco venoso localizado entre la arteria carótida común y la arteria tiroidea superior. Este arco venoso drenaba hacia arriba en la vena facial común y hacia abajo en la vena yugular interna. El conocimiento de las variaciones anatómicas y morfológicas en las venas de cabeza y cuello es esencial para llevar a cabo procedimientos quirúrgicos exitosos en estas regiones.

Abstract The superficial veins, especially the external jugular vein are increasingly used for cannulation or diagnostic procedures, intravenous therapy, parenteral nutrition in debilitated patients. Variations in the venous drainage of the head and neck are important not only for anatomists and radiologists but also for surgeons. During routine dissection in the Laboratory of Morphology, University of Pamplona in a 75 year-old male cadaver in the region face and neck anatomical variations and unusual drainage patterns were found, which were dissected carefully and morphological details were photographed; these variations consisted of unilateral absence of external jugular vein. The lingual vein, the infrahyoid vein and the superior thyroid vein had transverse venous connections that drained into a venous arch located between the common carotid artery and the superior thyroid artery. This draining venous arch upward in the common facial vein and down into the internal jugular vein. Knowledge of the anatomical and morphological variations in the veins of the head and neck is essential to carry out successful surgical procedures in these regions.

Lingual Artery-Retromandibular Vein Fistula Four Years after an Uncomplicated Carotid Endarterectomy: Case Report and Review of Possible Etiologies and Treatment Options.

The external carotid artery's lingual branch to retromandibular venous fistula following a carotid endarterectomy has not been reported earlier in literature. We report a unique case of an 87-year-old man who had a right-sided carotid endarterectomy in 2009 and presented four years later with complaints of fullness and discomfort in the area of right parotid gland with associated pulsatile tinnitus. A computed tomography (CT) scan of the neck revealed a deep portion of the right parotid gland having abnormal aneurysmal dilatation of a vascular structure, which appeared to be an arteriovenous fistula between branches of right external carotid artery and the retromandibular vein. Conventional catheter angiogram showed a complex arteriovenous fistula seen with the right retromandibular vein receiving multiple small arterial feeders from the right external carotid artery via its lingual artery branch. Slight reflux was noted into the right pterygoid plexus, right maxillary, and right submental veins as well. Surgical treatment was deferred due to high risk of inadvertent facial nerve injury from extensive parotid dissection involved in the procedure. Transarterial embolization of five discrete arterial branches from the right external carotid artery supplying the fistula was performed using particles with resultant remarkable slowing of the venous drainage into the retromandibular vein. After the procedure, his tinnitus and ear fullness resolved completely. The presence of arteriovenous fistula after carotid endarterectomy is a rare yet serious complication and therefore should be diagnosed early and treated promptly. The article highlights the relevant literature on arteriovenous fistula formation in the setting of arterial patch, intraoperative shunting, and surgical-site infections.

Absence of retromandibular vein associated with atypical formation of external jugular vein in the parotid region.

Veins of the head and neck exhibiting anatomical variations or malformations are clinically significant. Anatomical variation in the external jugular vein is very common. However, anatomical variation in the retromandibular vein is rare. In this paper, we report a rare case of complete absence of the retromandibular vein. In the absence of the retromandibular vein, the maxillary vein divided into anterior and posterior divisions. The posterior division joined the superficial temporal vein to form an atypical external jugular vein, and the anterior division joined the facial vein to form an anonymous vein. In clinical practice, radiologists and surgeons use the retromandibular vein as a guide to expose the branches of the facial nerve during superficial parotidectomy. Therefore, absence of the retromandibular vein is a hurdle during this procedure and may affect the venous drainage pattern from the head and neck.