Physiologic variations of the internal jugular vein surface, role of the omohyoid muscle, a preliminary echographic study

Ultrasonographic measurements of the omohyoid muscle during shoulder muscles contraction

BACKGROUND

The main function of the omohyoid muscle is to depress and withdraw the hyoid bone. This is an integral part of the swallowing process facilitating hyoid stabilization for tongue movement. Although the muscle is inferiorly attached to the scapula bone, its function during shoulder or scapula muscles contraction has yet not been studied.

AIM

To investigate whether changes occur in omohyoid muscle morphology during shoulder muscles contraction.

METHODS

The study included 40 healthy subjects (20 males and 20 females, Mean age: 25.68 (± 2.90) years) examined via diagnostic ultrasound. Omohyoid muscle morphology measurements (thickness and cross-sectional area) during different shoulder position (0°, 90° abduction and elevation) in rest and during isomteric contraction were evaluated.

RESULTS

The omohyoid muscle was activated when the shoulder was isometrically abducted at 90° abduction. Thickness and the cross-sectional area of the lower belly increased during contractions at 90° abduction compared with a resting position at 90° (p value < 0.01). No changes occurred at 0° isometric abduction. The CSA of the muscle was found to be significantly larger (p < 0.001) during contraction at 90° abduction compared with contraction at 0° abduction.

CONCLUSION

Omohyoid muscle was most contracted during abduction position with abduction shoulder muscles isometric contraction. Changes of the scapula position might influence omohyoid muscle function.

Anatomical diversity of inferior belly of the omohyoid muscle - Anatomical, physiological and surgical paradigm

Omohyoid muscle is one of the infrahyoid muscles of the neck which consists of two bellies combined at an angle by an intermediate tendon. The inferior belly is a flat, narrow band, which inclines forwards and upwards in the lower part of the neck. It generally originates from the upper border of the scapula, medial to scapular notch. The present case showed unilateral anomalous attachment of the inferior belly of the omohyoid on the medial part of clavicle on left side. Inferior belly was 2.2cm lateral to left sternoclavicular joint with 3.2 and 1.5cm in length and breadth, innervated by ansa cervicalis. Only 3% of this type of variation has been observed until now according to previous literature. Anterior and posterior triangles of neck on both sides of the cadaver were dissected during routine dissection for undergraduate teaching. There was no scapular attachment of inferior belly of the omohyoid on the left side. It was directly originating from the upper surface of the medial side of the left clavicle. Variation in the attachment of inferior belly can have a direct impact on the internal jugular vein and brachial plexus during neck surgeries or trauma due to its close relation to the mentioned structures. This variation should also be taken care during infrahyoid myocutaneus flap extraction for reconstruction surgery of tongue in cases of lingual carcinoma.

Anatomical relationship between the omohyoid muscle and the internal jugular vein on ultrasound guidance

Background

Internal jugular vein catheterization is widely used in clinical practice, and there are many related studies on internal jugular vein catheterization. However, the omohyoid muscle, which is adjacent to the internal jugular vein, is a rarely mentioned muscle of the infrahyoid muscles group. The purpose of this study is to explore the anatomical relationship between the omohyoid muscle and the internal jugular vein on ultrasound guidance and provide a theoretical reference for jugular puncture and catheterization.

Methods

The study included 30 volunteers. The volunteer’s head lay in the neutral position and was then turned to the left at an angle of 30°, 45° and 60° with the bed surface, as verified using an adjustable protractor. A high-frequency ultrasound probe (6–14 Hz) was used to examine the plane of the apex of sternocleidomastoid triangle (PAST), the triangle consists of anatomical landmarks: a base was clavicle, its sides – heads of sternocleidomastoid muscle. And the plane of the middle of sternocleidomastoid triangle(PMST) which was a horizontal line, connecting midpoints of both sides. The right omohyoid muscle (OM) and the right internal jugular vein (IJV) were observed and recorded for statistical analysis.

Results

There were statistically significant differences in the number of overlapping cases of OM and IJV at each head rotation angle between the PAST and PMST groups. There were statistically significant differences between the angles which OM and IJV centre point line and the left horizontal position of the PAST and PMST at different body angles.

Conclusion

The traditional middle route puncture point is the apex of the sternocleidomastoid triangle, which can effectively avoid injury to the omohyoid muscle, to an extent.

Trail registration

ChiCTR2000034233, Registered 29/06/2020. www. Chinese Clinical Trial Registry.gov.

An anomalous muscle clinging around the inferior belly of omohyoid muscle

Sternohyoid, sternothyroid, omohyoid and thyrohyoid muscles belong to a group of muscles called infrahyoid muscles. A few variations of these muscles and additional muscles in this area have been reported. We report an anomalous muscle in this area. The anomalous muscle took its origin from the posterior surface of the manubrium sterni and was inserted to the posterior surface of the clavicle. This muscle was 6 cm long and interestingly, it made a loop, which was clinging on to the inferior belly of omohyoid posteriorly, superiorly and anteriorly. The muscle was situated between the lower end of sternocleidomastoid and the carotid sheath. It was supplied by ansa cervicalis. Knowledge of this muscle could be useful in surgeries like removal of cervical rib, and cervical lymph node clearance. Hypertrophy of this muscle might compress the internal jugular vein.

Bilateral clavicular attachment of omohyoid muscle

Omohyoid muscle present in cervical region is of particular importance to anatomists as it defines anteriorly the carotid triangle and divides the posterior cervical triangle. It has superior and inferior bellies and an intermediate common tendon. Like sternohyoid, sternothyroid and thyrohyoid muscles, omohyoid is also an infrahyoid muscle, but it differs from them in its course. The infrahyoid muscles are formed from a muscle primordium occurring in the anterior cervical area. Anderson (Anderson, 1881) theorized that the superior belly of the omohyoid muscle is a true infrahyoid muscle, whereas the inferior belly most likely shares a common embryology with the subclavius muscle. In the present study, during routine dissection in the neck region of an adult male cadaver of 50 years age, an anomalous origin of inferior belly of omohyoid with absence of intermediate tendon was observed bilaterally. It was arising from clavicle on both sides. Both the muscle bellies were measured from the lateral end of fascial sling. The inferior belly of omohyoid extending from the lateral margin of sling to clavicular surface was measured 3.3cm in length on left side and 3.6cm on right side. The omohyoid is important in neck dissections because it is considered as an ideal landmark for level III and IV lymph node metastases. Knowledge of variations of this muscle is very important for surgeries in neck region because of its close relation to the internal jugular vein and brachial plexus. Its crucial relationship to vascular structures in the neck makes it an important landmark during neck surgeries.

Enhanced cerebral perfusion during brief exposures to cyclic intermittent hypoxemia

Cerebral vasodilation and increased cerebral oxygen extraction help maintain cerebral oxygen uptake in the face of hypoxemia. This study examined cerebrovascular responses to intermittent hypoxemia in eight healthy men breathing 10% O2 for 5 cycles, each 6 min, interspersed with 4 min of room air breathing. Hypoxia exposures raised heart rate ( P < 0.01) without altering arterial pressure, and increased ventilation ( P < 0.01) by expanding tidal volume. Arterial oxygen saturation ([Formula: see text]) and cerebral tissue oxygenation ([Formula: see text]) fell ( P < 0.01) less appreciably in the first bout (from 97.0 ± 0.3% and 72.8 ± 1.6% to 75.5 ± 0.9% and 54.5 ± 0.9%, respectively) than the fifth bout (from 94.9 ± 0.4% and 70.8 ± 1.0% to 66.7 ± 2.3% and 49.2 ± 1.5%, respectively). Flow velocity in the middle cerebral artery ( VMCA) and cerebrovascular conductance increased in a sigmoid fashion with decreases in [Formula: see text] and [Formula: see text]. These stimulus-response curves shifted leftward and upward from the first to the fifth hypoxia bouts; thus, the centering points fell from 79.2 ± 1.4 to 74.6 ± 1.1% ( P = 0.01) and from 59.8 ± 1.0 to 56.6 ± 0.3% ( P = 0.002), and the minimum VMCA increased from 54.0 ± 0.5 to 57.2 ± 0.5 cm/s ( P = 0.0001) and from 53.9 ± 0.5 to 57.1 ± 0.3 cm/s ( P = 0.0001) for the [Formula: see text]- VMCA and [Formula: see text]- VMCA curves, respectively. Cerebral oxygen extraction increased from prehypoxia 0.22 ± 0.01 to 0.25 ± 0.02 in minute 6 of the first hypoxia bout, and remained elevated between 0.25 ± 0.01 and 0.27 ± 0.01 throughout the fifth hypoxia bout. These results demonstrate that cerebral vasodilation combined with enhanced cerebral oxygen extraction fully compensated for decreased oxygen content during acute, cyclic hypoxemia.

NEW & NOTEWORTHY Five bouts of 6-min intermittent hypoxia (IH) exposures to 10% O2 progressively reduce arterial oxygen saturation ([Formula: see text]) to 67% without causing discomfort or distress. Cerebrovascular responses to hypoxemia are dynamically reset over the course of a single IH session, such that threshold and saturation for cerebral vasodilations occurred at lower [Formula: see text] and cerebral tissue oxygenation ([Formula: see text]) during the fifth vs. first hypoxia bouts. Cerebral oxygen extraction is augmented during acute hypoxemia, which compensates for decreased arterial O2 content.

Clinical Significance of an Unusual Variation: Anomalous additional belly of the sternothyroid muscle

The infrahyoid muscles are involved in vocalisation and swallowing; among these, the sternothyroid muscle is derived from the common primitive sheet. The improper differentiation of this muscle may therefore result in morphological variations. We report an unusual variation found during the dissection of a 65-year-old male cadaver at the Sri Manakula Vinayagar Medical College, Madagadipet, Pondicherry, India, in 2015. An anomalous belly of the right sternothyroid muscle was observed between the internal jugular (IJ) vein and the internal carotid artery with an additional insertion into the tympanic plate and petrous part of the temporal bone and the presence of a levator glandulae thyroideae muscle. The anomalous muscle may compress the IJ vein if it is related to the neurovascular structures of neck; hence, knowledge of variations of the infrahyoid muscles can aid in the evaluation of IJ vein compression among patients with idiopathic symptoms resulting from venous congestion.

Duplicated posterior belly of digastric muscle and absence of omohyoid muscle: a case report and review of literature

PURPOSE

We report a unique case of duplicated posterior belly of digastric muscle and absence of omohyoid muscle, review literatures and discuss its clinical importance.

MATERIALS AND METHODS

An abnormal strip of muscle was found during the routine functional neck dissection in a 58-year-old man, who suffered from moderately differentiated squamous cell carcinoma of right tongue. We check the anatomical features and search for similar variations in the past literatures.

RESULTS

The abnormal strip of muscle was attached to mastoid process, passed anteroinferiorly into the infrahyoid muscles. The muscle was as long as, but narrower than the posterior belly of the digastric muscle. So far, only one case of this anomaly was reported. Meanwhile, the omohyoid muscle was confirmed to be absent in the right neck of this patient.

CONCLUSIONS

To our knowledge, report of variations of both digastric muscle and omohyoid muscle, this variation mostly derives from abnormal development of the mesenchyme in the branchial arches. Attention should be paid to such variations, which might influence surgical procedures.

Cross-sectional area variations of internal jugular veins during supine head rotation in multiple sclerosis patients with chronic cerebrospinal venous insufficiency: a prospective diagnostic controlled study with duplex ultrasound investigation

Background

Normally, chronic cerebrospinal venous insufficiency (CCSVI) has been studied using echo-colour Doppler (ECD). Subjects are examined in the supine and sitting positions, in accordance with a static protocol without rotation of the head. A dynamic approach, to assess venous sizes with different degrees of head rotation, has only been performed to improve jugular venous catheterisation. These echographic studies have suggested that head rotation to the contralateral side increases the cross-sectional area (CSA) of the internal jugular veins (IJVs) in supine subjects. Our goal was to evaluate the behaviour of CSA of the IJVs during supine head rotation in multiple sclerosis (MS) patients with CCSVI, compared to healthy controls (HCs).

Methods

The IJVs of 313 MS patients with CCSVI (male 43.8%, male/female 137/176; mean age 45 years old, range 19–77 years) and 298 HCs, matched by gender (male 43.6%, male/female 130/168) and age (mean age 46 years old, range 20–79 years), were compared using ECD. Their CSAs were evaluated with the subjects seated in a tiltable chair, first in the supine position at the level of the cricoid cartilage, with the head in a neutral position, and then after contralateral rotation to 90° from midline.

Results

Significant differences between the jugular CSAs before and after head rotation were observed only in the MS patients for the IJVs with wall collapse (F[6,1215] = 6414.57, p < 0.001), showing on longitudinal scans a typical “hourglass” aspect that we defined as “miopragic”. No significant difference was found in the distribution of these miopragic veins with regard to MS duration. There was a strong association between the CCSVI scores and the complexity of jugular morphological types (Χ² [9, N = 313] = 75.183, p < 0.001). Wall miopragia was mainly observed in MS patients with SP (59.3%) and PP (70.0%) clinical forms, compared to RR (48.3%) forms (p = 0.015).

Conclusion

A dynamic ECD approach allowed us to detect IJVs with a significant increase in their CSAs during head rotation, but only in MS subjects. This feature, most likely the expression of congenital wall miopragia, could be secondary to dysregulation of collagen synthesis, but further histochemical studies will be needed to confirm this hypothesis.

Relationship between the ansa cervicalis and the omohyoid muscle: clinical consequences in parathyroid surgery

PURPOSE

To determine the position of the lower loop of the ansa cervicalis (AC) compared to the inferior edge of the omohyoid muscle to guide minimally invasive surgery for the lateral oblique approach of parathyroid glands.

METHODS

Authors performed 36 anatomical dissections in the laboratory of anatomy (Laboratoire d'Anatomie Des Alpes Françaises) of the Grenoble medical school in 2012 on human cadavers. They independently measured the distance between the caudal extremity of the AC and the lower edge of the superior belly of the omohyoid muscle. Then, they controlled this measure on pictures.

RESULTS

The study shows a majority of long AC (under the omohyoid muscle) in 66.7 % of cases. In addition, the AC was located on an average value of 0.1 cm below the lower edge of the omohyoid muscle (median -0.5 cm). Thus, two-thirds of AC are between 0 and -2 cm under the omohyoid muscle. Furthermore, the AC is generally non-symmetrical: there is a mean difference of 1.3 cm between the left and right AC. In this series, there are as many long AC on the right side as on the left side.

CONCLUSIONS

These results are in contradiction with literature data. To preserve the ansa cervicalis and its phonatory functions, it is necessary for the surgeon to perform a systematic per operative identification of the AC because the position of the AC is mainly under the omohyoid muscle and because of an asymmetry. Per operative neurostimulation and/or magnified lenses might be helpful during the surgical approach.

Small internal jugular veins with restricted outflow are associated with severe multiple sclerosis: a sonographer-blinded, case-control ultrasound study

BACKGROUND

Recent evidence has indicated an association between chronic cerebrospinal venous insufficiency (CCSVI) and multiple sclerosis. Small internal jugular veins (IJVs) (with a cross-sectional area of less than 0.4 cm²) have been previously described as difficult to catheterize, and their presence may potentially affect cerebrospinal venous drainage. In this blinded extracranial color-Doppler study we had two principal aims: first, to assess prevalence of CCSVI among Serbian MS patients compared to healthy controls; and second, to assess prevalence of small IJVs (with a CSA ≤ 0.4 cm²) among MS patients and controls.

METHODS

The sixty seven unrelated patients with clinical isolated syndrome (CIS), relapsing-remitting (RR), secondary progressive (SP) and primary progressive (PP) multiple sclerosis and 21 healthy controls were examined by high-resolution color-Doppler.

RESULTS

The ultrasonographic criteria of CCSVI (according to Zamboni) were positive in 11.9% of the patients and in none of the control subjects. The CCSVI-positive patients had significantly longer disease durations and were significantly more disabled (measured by their Expanded Disability Status Scale (EDSS) and Multiple Sclerosis Severity Score (MSSS) scores), but after adjustment for gender and disease duration, CCSVI was not an independent risk factor for multiple sclerosis severity. The small IJVs were found in 28.4% of the patients and 28.6% of the controls. The patients with small IJVs were associated with decreased venous outflow from the brain and presented with longer disease durations and significantly higher EDSS and MSSS scores compared to patients without small IJVs. A multivariate logistic regression analysis adjusted for gender and disease duration showed that small IJV is an independent factor associated with multiple sclerosis severity (EDSS ≥6) (adjusted OR = 8.9, 95% CI: 1.8-45.6, p = 0.007). Among patients with small IJVs the 36.84% were also CCSVI positive.

CONCLUSIONS

Both, CCSVI and small IJVs seem to influence or follow MS severity, but only small IJVs turned out to be an independent factor in this study. Thus, small IJVs with restricted outflow, which might be aspects of CCSVI different from the criteria originally described by Zamboni, emerge as a cofactor in the multifactorial pathophysiology of multiple sclerosis.

How yawning switches the default-mode network to the attentional network by activating the cerebrospinal fluid flow

Yawning is a behavior to which little research has been devoted. However, its purpose has not yet been demonstrated and remains controversial. In this article, we propose a new theory involving the brain network that is functional during the resting state, that is, the default mode network. When this network is active, yawning manifests a process of switching to the attentional system through its capacity to increase circulation of cerebrospinal fluid (CSF), thereby increasing clearance of somnogenic factors (prostaglandin D(2), adenosine, and others) accumulating in the cerebrospinal fluid.

What went wrong? The flawed concept of cerebrospinal venous insufficiency

In 2006, Zamboni reintroduced the concept that chronic impaired venous outflow of the central nervous system is associated with multiple sclerosis (MS), coining the term of chronic cerebrospinal venous insufficiency ('CCSVI'). The diagnosis of 'CCSVI' is based on sonographic criteria, which he found exclusively fulfilled in MS. The concept proposes that chronic venous outflow failure is associated with venous reflux and congestion and leads to iron deposition, thereby inducing neuroinflammation and degeneration. The revival of this concept has generated major interest in media and patient groups, mainly driven by the hope that endovascular treatment of 'CCSVI' could alleviate MS. Many investigators tried to replicate Zamboni's results with duplex sonography, magnetic resonance imaging, and catheter angiography. The data obtained here do generally not support the 'CCSVI' concept. Moreover, there are no methodologically adequate studies to prove or disprove beneficial effects of endovascular treatment in MS. This review not only gives a comprehensive overview of the methodological flaws and pathophysiologic implausibility of the 'CCSVI' concept, but also summarizes the multimodality diagnostic validation studies and open-label trials of endovascular treatment. In our view, there is currently no basis to diagnose or treat 'CCSVI' in the care of MS patients, outside of the setting of scientific research.

Catheter venography and endovascular treatment of chronic cerebrospinal venous insufficiency

Multiple sclerosis (MS) is a disorder characterized by damage to the myelin sheath insulation of nerve cells of the brain and spinal cord affecting nerve impulses which can lead to numerous physical and cognitive disabilities. The disease, which affects over 500,000 people in the United States alone, is widely believed to be an autoimmune condition potentially triggered by an antecedant event such as a viral infection, environmental factors, a genetic defect or a combination of each. Chronic cerebrospinal venous insufficiency (CCSVI) is a condition characterized by abnormal venous drainage from the central nervous system that has been theorized to have a possible role in the pathogenesis and symptomatology of MS (1). A significant amount of attention has been given to this theory as a possible explanation for the etiology of symptoms related to MS patients suffering from this disease. The work of Dr. Zamboni, et al, who reported that treating the venous stenoses causing CCSVI with angioplasty resulting in significant improvement in the symptoms and quality of life of patients with MS (2) has led to further interest in this theory and potential treatment. The article presented describes endovascular techniques employed to diagnose and treat patients with MS and CCSVI.

Internal jugular vein entrapment in a multiple sclerosis patient

We describe a multiple sclerosis patient presenting with compression of the internal jugular vein caused by aberrant omohyoid muscle. Previously this patient underwent balloon angioplasty of the same internal jugular vein. Ten months after this endovascular procedure, Doppler sonography revealed totally collapsed middle part of the treated vein with no outflow detected. Still, the vein widened and the flow was restored when the patient's mouth opened. Thus, the abnormality was likely to be caused by muscular compression. Surgical exploration confirmed that an atypical omohyoid muscle was squeezing the vein. Consequently, pathological muscle was transected. Sonographic control three weeks after surgical procedure revealed a decompressed vein with fully restored venous outflow. Although such a muscular compression can be successfully managed surgically, future research has to establish its clinical relevance.

Effect of slosh mitigation on histologic markers of traumatic brain injury: laboratory investigation

OBJECT

Helmets successfully prevent most cranial fractures and skull traumas, but traumatic brain injury (TBI) and concussions continue to occur with frightening frequency despite the widespread use of helmets on the athletic field and battlefield. Protection against such injury is needed. The object of this study was to determine if slosh mitigation reduces neural degeneration, gliosis, and neuroinflammation.

METHODS

Two groups of 10 adult male Sprague-Dawley rats were subjected to impact-acceleration TBI. One group of animals was fitted with a collar inducing internal jugular vein (IJV) compression prior to injury, whereas the second group received no such collar prior to injury. All rats were killed 7 days postinjury, and the brains were fixed and embedded in paraffin. Tissue sections were processed and stained for markers of neural degeneration (Fluoro-Jade B), gliosis (glial fibrillary acidic protein), and neuroinflammation (ionized calcium binding adapter molecule 1).

RESULTS

Compared with the controls, animals that had undergone IJV compression had a 48.7%-59.1% reduction in degenerative neurons, a 36.8%-45.7% decrease in reactive astrocytes, and a 44.1%-65.3% reduction in microglial activation.

CONCLUSIONS

The authors concluded that IJV compression, a form of slosh mitigation, markedly reduces markers of neurological injury in a common model of TBI. Based on findings in this and other studies, slosh mitigation may have potential for preventing TBI in the clinical population.

Variation of the infrahyoid muscle: duplicated omohyoid and appearance of the levator glandulae thyroideae muscles

The embryologic origin of the omohyoid muscle is different from that of the other neck muscles. A number of variations such as the absence of muscle, variable sites of origin and insertion, and multiple bellies have been reported. However, variations in the inferior belly of the omohyoid muscle are rare. There have been no reports of the combined occurrence of the omohyoid muscle variation with the appearance of the levator glandulase thyroideae muscle. Routine dissection of a 51- year-old female cadaver revealed a duplicated omohyoid muscle and the appearance of the levator glandulae thyroideae muscle. In this case, the two inferior bellies of the omohyoid muscle were found to originate inferiorly from the superior border of the scapula. One of the inferior bellies generally continued to the superior belly with the tendinous intersection. The other inferior belly continued into the sternohyoid muscle without the tendinous intersection. In this case, the levator glandulae thyroideae muscle appeared on the left side, which attached from the upper border of the thyroid gland to the inferior border of the thyroid cartilage. These variations are significant for clinicians during endoscopic diagnosis and surgery because of the arterial and nervous damage due to iatrogenic injuries. The embryologic origins of the omohyoid and levator glandulae thyroideae muscles may be similar based on the descriptions in the relevant literature.

A study of anatomical variability of the omohyoid muscle and its clinical relevance

OBJECTIVE

The omohyoid muscle is a long, thin muscle consisting of superior and inferior bellies and an intermediate tendon, which runs obliquely in the lateral cervical region. The omohyoid is important in neck dissections because it is the surgical landmark for level III and IV lymph node metastases.

METHODS

In the present study, the anterior and posterior triangle of the neck was dissected in 35 male cadavers and observed for variations in the omohyoid bilaterally. Observations were focused on variations in number, attachments, and position of omohyoid.

RESULTS

Among the 35 cadavers studied, double omohyoid was present in one cadaver, inferior belly originated from the clavicle in three cadavers, superior belly merged with the sternohyoid in two cadavers, and the omohyoid received additional slips from the sternum in one cadaver. Standard attachment and position of the omohyoid was observed in the remaining cadavers.

CONCLUSION

Variations of this muscle are important because of its close relation to the large vessels and brachial plexus. Because of the direct adhesion of the intermediate tendon to the anterior wall of the internal jugular vein and its connection with it through a thin lamina of the pretracheal layer of the cervical fascia, the contraction of the omohyoid muscle has a direct effect on the lumen of this vessel.

Unusual origin of the omohyoid muscle

An unusual origin of the right omohyoid muscle was found during cadaveric dissection. The muscle originated from the transverse process of C6 and inserted into the scapula. No other muscular anomalies of the neck were found. Although many anomalies of the omohyoid muscle have been described, a proximal attachment to the cervical spine is apparently quite rare. Knowledge of the many anomalies that can potentially occur in the cervical region is necessary in routine surgical intervention of this area. We believe this to be the first reported instance of the superior belly of the "omo" hyoid originating from the cervical region as we have described.

Venous collateral blood flow assessed by Doppler ultrasound after unilateral radical neck dissection

Removal of the internal jugular vein (IJV) in unilateral radical neck dissection (rND) necessitates redirection of cerebrovenous blood to collateral pathways. If adaptation is insufficient, neurologic sequelae develop that are due to impaired venous drainage and increased intracranial pressure. The authors studied venous hemodynamic effects of unilateral rND using Doppler and duplex ultrasound in 17 patients. Blood flow velocities (BFVs) were recorded from the distal IJV (dIJV) and the vertebral vein (VV) before and 9 to 88 days after surgery. A preoperative compression test of the dIJV was performed to identify the side of dominant drainage. The BFV increased in the contralateral dIJV after right-sided rND (n = 10) by 111% (range, 50% to 320%), and after left-sided rND (n = 7) by 34% (range, 5% to 105%). In the contralateral VV, a rise of BFV by 75% was found. Our results confirm the role of the contralateral dIJV as the predominant collateral pathway. The VVs serve as an important additional major outflow. Doppler ultrasound may help to identify patients at risk of insufficient cerebrovenous drainage after rND.