Variations of the trapezius branch of the accessory nerve: an anatomic study

Although modified radical neck dissections have increased in popularity to reduce morbidity secondary to intraoperative accessory nerve damage, inadvertent injury still often occurs. As this phenomenon is thought to be due to anatomic variation in the trapezius branch of the accessory nerve, it is imperative to better understand the nuances of these anatomic variations to better inform surgical decision-making. A total of 24 accessory nerves were dissected, exposed, and traced in 15 cadavers. Three aspects of the accessory nerve were identified and recorded: the course of the trapezius branch in relation to the sternocleidomastoid, the number of trapezius branches at muscle insertion, and the number of cervical rootlet contributions. Four different anatomic patterns for the trapezius branch were identified, with the most common being where the trapezius branch separates from the main accessory nerve just medial to the sternocleidomastoid and courses deep to the sternocleidomastoid (58.3%). Most (75%) trapezius branches entered the muscle as a single nerve, whereas some (21%) were inserted as two separate nerves. The number of cervical rootlet contributions for each trapezius branch varied from zero to three. Bilateral anatomic variations were also noted. Even when the accessory nerve and its branches are thought to be spared during neck dissection, patients may postoperatively present with different degrees of accessory nerve damage. There may be unrecognized anatomic pathways that the nerve takes that may confer a higher risk of unintentional damage, especially those that have greater exposure within the anterior triangle unprotected by the sternocleidomastoid.

Morphological analysis of neck muscle nerves and neurons in cats

Previous studies have failed to show morphological differences between neck muscle alpha and gamma motor fibers or alpha and gamma motoneurons. The present study aimed to investigate the morphological features of neck muscle motor nerves and motoneurons in cats. To determine the morphological features of peripheral motor fibers, the value of the outer contours of each fiber was converted into a perfect circle after ganglionectomy to remove sensory fibers, and the fiber diameters were calculated based on their circumferences. The sizes of neck motor fibers in the peripheral nerves had an evident bimodal distribution into small and large fiber groups, as depicted in histograms. The sizes of small and large motor fibers ranged from 2 to 12 µm and from 12 to 40 µm, respectively. The small fiber group is likely to correspond to gamma motor fibers and the large fiber group to alpha motor fibers. The morphological features of neck muscle motoneurons sectioned in the horizontal plane were examined using the horseradish peroxidase (HRP) retrograde labeling technique. The diameters of the biventer cervicis and complexus motoneurons had bimodal distributions. The inflection point between the small and large diameter population was 28 µm for the biventer cervicis and 26 µm for the complexus. We also observed that larger neurons displayed more dendrites. In conclusion, we could identify morphological differences likely to correlate with alpha and gamma motoneurons in both neck muscle peripheral nerves and neck motoneurons.

The Great Auricular Nerve Trigger Site: Anatomy, Compression Point Topography, and Treatment Options for Headache Pain

BACKGROUND

Peripheral nerve decompression surgery can effectively address headache pain caused by compression of peripheral nerves of the head and neck. Despite decompression of known trigger sites, there are a subset of patients with trigger sites centered over the postauricular area coursing. The authors hypothesize that these patients experience primary or residual pain caused by compression of the great auricular nerve.

METHODS

Anatomical dissections were carried out on 16 formalin-fixed cadaveric heads. Possible points of compression along fascia, muscle, and parotid gland were identified. Ultrasound technology was used to confirm these anatomical findings in a living volunteer.

RESULTS

The authors' findings demonstrate that the possible points of compression for the great auricular nerve are at Erb's point (point 1), at the anterior border of the sternocleidomastoid muscle in the dense connective tissue before entry into the parotid gland (point 2), and within its intraparotid course (point 3). The mean topographic measurements were as follows: Erb's point to the mastoid process at 7.32 cm/7.35 (right/left), Erb's point to the angle of the mandible at 6.04 cm/5.89 cm (right/left), and the posterior aspect of the sternocleidomastoid muscle to the mastoid process at 3.88 cm/4.43 cm (right/left). All three possible points of compression could be identified using ultrasound.

CONCLUSIONS

This study identified three possible points of compression of the great auricular nerve that could be decompressed with peripheral nerve decompression surgery: Erb's point (point 1), at the anterior border of the sternocleidomastoid muscle (point 2), and within its intraparotid course (point 3).

microRNA let-7i-5p mediates the relationship between muscle fat infiltration and neck pain disability following motor vehicle collision: a preliminary study

Persistent neck-pain disability (PNPD) is common following traumatic stress exposures such as motor vehicle collision (MVC). Substantial literature indicates that fat infiltration into neck muscle (MFI) is associated with post-MVC PNPD. However, little is known about the molecular mediators underlying this association. In the current study, we assessed whether microRNA expression signatures predict PNPD and whether microRNA mediate the relationship between neck MFI and PNPD. A nested cohort of 43 individuals from a longitudinal study of MVC survivors, who provided blood (PAXgene RNA) and underwent magnetic resonance imaging (MRI), were included in the current study. Peritraumatic microRNA expression levels were quantified via small RNA sequencing, neck MFI via MRI, and PNPD via the Neck Disability Index two-weeks, three-months, and twelve-months following MVC. Repeated measures regression models were used to assess the relationship between microRNA and PNPD and to perform mediation analyses. Seventeen microRNA predicted PNPD following MVC. One microRNA, let-7i-5p, mediated the relationship between neck MFI and PNPD. Peritraumatic blood-based microRNA expression levels predict PNPD following MVC and let-7i-5p might contribute to the underlying effects of neck MFI on persistent disability. In conclusion, additional studies are needed to validate this finding.

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.

Management of Anterocapitis and Anterocollis: A Novel Ultrasound Guided Approach Combined with Electromyography for Botulinum Toxin Injection of Longus Colli and Longus Capitis

Chemodenervation of cervical musculature using botulinum neurotoxin (BoNT) is established as the gold standard or treatment of choice for management of Cervical Dystonia (CD). The success of BoNT procedures is measured by improved symptomology while minimizing side effects and is dependent upon many factors including: clinical pattern recognition, identifying contributory muscles, BoNT dosage, and locating and safely injecting target muscles. In patients with CD, treatment of anterocollis (forward flexion of the neck) and anterocaput (anterocapitis) (forward flexion of the head) are inarguably challenging. The longus Colli (LoCol) and longus capitis (LoCap) muscles, two deep cervical spine and head flexor muscles, frequently contribute to these patterns. Localizing and safely injecting these muscles is particularly challenging owing to their deep location and the complex regional anatomy which includes critical neurovascular and other structures. Ultrasound (US) guidance provides direct visualization of the LoCol, LoCap, other cervical muscles and adjacent structures reducing the risks and side effects while improving the clinical outcome of BoNT for these conditions. The addition of electromyography (EMG) provides confirmation of muscle activity within the target muscle. Within this manuscript, we present a technical description of a novel US guided approach (combined with EMG) for BoNT injection into the LoCol and LoCap muscles for the management of anterocollis and anterocaput in patients with CD.

Relationship of the lobular branch of the great auricular nerve to the tympanoparotid fascia: Spatial anatomy for salvage during face and neck lift

To enable selection of a safer suspension site to use in face and neck lifting procedures, the spatial relationship between the tympanoparotid fascia and the great auricular nerve should be clarified. In this study, we aimed to elucidate the position of the tympanoparotid fascia and the pathway of the lobular branch of the great auricular nerve traversing the tympanoparotid fascia. Twenty hemifaces from non-preserved bequeathed Korean cadavers (5 males, 7 females; mean age, 77.0 years) were dissected to determine the great auricular nerve distribution close to the tympanoparotid fascia of clinical significance for face and neck lift procedures. We observed the tympanoparotid fascia in all specimens (20 hemifaces). The tympanoparotid fascia was located anteriorly between the tragus and intertragic notch. Regarding the spatial relationship between the tympanoparotid fascia and the great auricular nerve, we found the sensory nerve entering the tympanoparotid fascia in all specimens (100%), and the depth from the skin was approximately 4.5 mm; in 65% of the specimens, the lobular branch was found to run close to the tympanoparotid fascia before going into the earlobe. Provided with relatively safer surface mapping to access the tympanoparotid fascia free of the lobular branch of the great auricular nerve, surgeons may better protect the lobular branch by anchoring the SMAS-platysma flap and thread to the deeper superior and anterior portions of the expected tympanoparotid fascia.

Frequency-dependent deficits in head steadiness in patients with nonspecific neck pain

Motor control impairments are reported in patients with nonspecific neck pain but the particular deficits in underlying regulatory systems are not known. Head steadiness is controlled both by voluntary and reflex systems that are predominantly effective within different frequency intervals. The aim of the present study was to investigate within which frequency range(s) potential motor control deficits may reside. The ability to keep the head stationary in space in response to unpredictable perturbations was tested in 71 patients with nonspecific neck pain and 17 healthy controls. Participants were exposed to pseudorandom horizontal rotations across 10 superimposed frequencies (0.185-4.115 Hz) by means of an actuated chair in three conditions; with a visual reference, and without vision with, and without a cognitive task. Below 1 Hz, patients kept the head less stable in space compared to healthy controls. Between 1 and 2 Hz, the head was stabilized on the trunk in both groups. Patients kept the head more stable relative to the trunk than relative to space compared to healthy controls. This was interpreted as higher general neck muscle co-activation in patients, which may be explained by altered voluntary control, or/and upregulated gamma motor neuron activity which increases the contribution of reflex-mediated muscle activation. Alternatively, increased muscle activity is secondary to vestibular deficits.

Anatomical variants of dorsal scapular nerve in relation to the middle scalene muscle in Japanese population

Dorsal scapular nerve (DSN) block is often performed in Japanese pain clinics to treat neck pain and katakori (a unique symptom in Japanese population characterized by myofascial pain syndromes such as shoulder girdle pain). However, to the best of our knowledge, there are only a few studies regarding anatomical variations in DSN paths around the middle scalene muscle (MSM) in Japanese population. Thus, we conducted a cadaveric study to examine anatomical variations in DSN paths around the MSM in Japanese population.DSN anatomies of 70 adult Japanese cadavers used for research and gross anatomy practice at the Tokai University School of Medicine between 2015 and 2016 were examined.In all cadavers, DSNs originated from the brachial plexus (BP) and innervated the rhomboid major, rhomboid minor, and levator scapulae muscles via the MSM. Two types of DSN paths were observed: piercing-type (piercing the MSM) and anterior-type (running in front of the MSM). We surveyed all 140 sides in 70 Japanese cadavers; of these, 95 sides had piercing-type and 45 had anterior-type paths. Of the 70 cadavers, 42 had piercing-type and 17 had anterior-type paths on both the sides. In 9 cadavers, the left and right sides had piercing-type and anterior-type paths, respectively. In the other 2 cadavers, the right and left sides had piercing-type and anterior-type paths, respectively.We found 2 distinct anatomical variants for DSN paths around the MSM in this Japanese cohort. Our results suggest that the rate of anterior-type DSN path is higher in Japanese population. Therefore, it is necessary to maintain caution while injecting anesthetic agents during a DSN block and the type of DSN should be considered.

Catecholaminergic A1/C1 neurons contribute to the maintenance of upper airway muscle tone but may not participate in NREM sleep-related depression of these muscles

Neural mechanisms of obstructive sleep apnea, a common sleep-related breathing disorder, are incompletely understood. Hypoglossal motoneurons, which provide tonic and inspiratory activation of genioglossus (GG) muscle (a major upper airway dilator), receive catecholaminergic input from medullary A1/C1 neurons. We aimed to determine the contribution of A1/C1 neurons in control of GG muscle during sleep and wakefulness. To do so, we placed injections of a viral vector into DBH-cre mice to selectively express the hMD4i inhibitory chemoreceptors in A1/C1 neurons. Administration of the hM4Di ligand, clozapine-N-oxide (CNO), in these mice decreased GG muscle activity during NREM sleep (F_1,1,3=17.1, p<0.05); a similar non-significant decrease was observed during wakefulness. CNO administration had no effect on neck muscle activity, respiratory parameters or state durations. In addition, CNO-induced inhibition of A1/C1 neurons did not alter the magnitude of the naturally occurring depression of GG activity during transitions from wakefulness to NREM sleep. These findings suggest that A1/C1 neurons have a net excitatory effect on GG activity that is most likely mediated by hypoglossal motoneurons. However, the activity of A1/C1 neurons does not appear to contribute to NREM sleep-related inhibition of GG muscle activity, suggesting that A1/C1 neurons regulate upper airway patency in a state-independent manner.

Vestibular click-evoked myogenic potentials: sensitivity and factors determining abnormality in patients with multiple sclerosis

Vestibular evoked myogenic potential (VEMP) assesses the sacculo-spinal pathway. The aim of our study was to examine sensitivity and factors determining abnormality of VEMP, indicative of brainstem dysfunction, in patients with multiple sclerosis (MS). Thirty healthy subjects and 30 MS patients were examined. All healthy subjects showed a normal biphasic response. Twelve of the 30 MS patients (40%) had abnormal recordings. There was a significant difference between MS patients and control subjects with respect to P13 latency (longer in the MS group) and P13-N23 amplitude (lower in the MS group). VEMP abnormalities were statistically significantly related to the presence of brainstem demyelinative lesions and a weaker correlation was found with disease duration. Clinical signs of vestibular dysfunction at any point during the course of the disease did not seem to affect the chances of obtaining abnormal VEMPs. Although the sensitivity of VEMP in detecting abnormality in MS patients is relatively low, its significance is evident in that it is the only electrophysiological method that is able to detect dysfunction in central vestibular pathways. Multiple Sclerosis 2007; 13: 193–198. http://msj.sagepub.com

Proactive Selective Inhibition Targeted at the Neck Muscles: This Proximal Constraint Facilitates Learning and Regulates Global Control

While individual muscle function is known, the sensory and motor value of muscles within the whole-body sensorimotor network is complicated. Specifically, the relationship between neck muscle action and distal muscle synergies is unknown. This work demonstrates a causal relationship between regulation of the neck muscles and global motor control. Studying violinists performing unskilled and skilled manual tasks, we provided ultrasound feedback of the neck muscles with instruction to minimize neck muscle change during task performance and observed the indirect effect on whole-body movement. Analysis of ultrasound, kinematic, electromyographic and electrodermal recordings showed that proactive inhibition targeted at neck muscles had an indirect global effect reducing the cost of movement, reducing complex involuntary, task-irrelevant movement patterns and improving balance. This effect was distinct from the effect of gaze alignment which increased physiological cost and reduced laboratory-referenced movement. Neck muscle inhibition imposes a proximal constraint on the global motor plan, forcing a change in highly automated sensorimotor control. The proximal location ensures global influence. The criterion, inhibition of unnecessary action, ensures reduced cost while facilitating task-relevant variation. This mechanism regulates global motor function and facilitates reinforcement learning to change engrained, maladapted sensorimotor control associated with chronic pain, injury and performance limitation.

Surface Electromyographic Activity in Total Laryngectomy Patients following Laryngeal Nerve Transfer to Neck Strap Muscles

Hands-free triggering and pitch control would improve electrolarynx devices, which are inconvenient to use and sound unnatural. The present study tested the strategy of salvaging voice-related neural signals for hands-free electrolarynx control either by transferring cut recurrent laryngeal nerves (RLNs) to denervated neck strap muscles or by preserving strap muscles with their normal innervation. An RLN nerve transfer was performed at the time of total laryngectomy in 8 individuals, and in 5 of these subjects, strap muscles with intact ansa cervicalis innervation were also preserved for comparison. Neck surface electromyography performed over the strap muscles was used periodically for more than 1 year on phonatory and nonphonatory tasks. Signals were eventually obtained in all subjects from both RLN-innervated and ansa-innervated strap muscles that correlated with speech production. After 1 year, RLN-driven signals were larger than ansa-driven signals in magnitude, and their timing appeared better correlated with intended phonation. The results show that neck surface electromyography is an effective control source for hands-free electrolarynx activation, and that RLN transfer may provide the best approach for obtaining phonation-related activity.

Myofascial Trigger Points, Neck Mobility and Forward Head Posture in Unilateral Migraine

This paper describes the differences in the presence of myofascial trigger points (TrPs) in the upper trapezius, sternocleidomastoid, temporalis and suboccipital muscles between unilateral migraine subjects and healthy controls, and the differences in the presence of TrPs between the symptomatic side and the nonsymptomatic side in migraine subjects. In addition, we assess the differences in the presence of both forward head posture (FHP) and active neck mobility between migraine subjects and healthy controls and the relationship between FHP and neck mobility. Twenty subjects with unilateral migraine without side-shift and 20 matched controls participated. TrPs were identified when there was a hypersensible tender spot in a palpable taut band, local twitch response elicited by the snapping palpation of the taut band and reproduction of the referred pain typical of each TrP. Side-view pictures were taken in both sitting and standing positions to measure the cranio-vertebral angle. A cervical goniometer was employed to measure neck mobility. Migraine subjects showed a significantly greater number of active TrPs ( P < 0.001), but not latent TrPs, than healthy controls. Active TrPs were mostly located ipsilateral to migraine headaches ( P < 0.01). Migraine subjects showed a smaller cranio-vertebral angle than controls ( P < 0.001), thus presenting a greater FHP. Neck mobility in migraine subjects was less than in controls only for extension ( P = 0.02) and the total range of motion in flexion/extension ( P = 0.01). However, there was a positive correlation between the cranio-vertebral angle and neck mobility. Nociceptive inputs from TrPs in head and neck muscles may produce continuous afferent bombardment of the trigeminal nerve nucleus caudalis and, thence, activation of the trigeminovascular system. Active TrPs located ipsilateral to migraine headaches might be a contributing factor in the initiation or perpetuation of migraine.

Anatomic study of the musculus longus capitis flap

PURPOSE

To clearly delineate the anatomy of the musculus longus capitis, determine its clinical applications for reconstruction surgery, and provide a safer surgical method of developing the longus capitis muscle flap.

METHODS

Anatomical investigations were performed in seven adult cadavers (five cadavers for gross anatomy and two for transparent specimen preparation) with respect to the location, morphology, arterial supply, and innervation of the musculus longus capitis, as well as its spatial relationship with the cervical sympathetic trunk, superior cervical ganglion, carotid sheath, and other surrounding structures.

RESULTS

The musculus longus capitis is located anterior to the C1-6 vertebrae, segmentally supplied by branches of the ascending cervical artery, innervated by the C1-5 nerve, and spatially close to the cervical sympathetic trunk, superior cervical ganglion, and carotid sheath. These anatomic findings indicate that the development of a cranial or caudal pedicled longus capitis muscle flap is feasible.

CONCLUSION

The musculus longus capitis can be developed into a cranial or caudal pedicled flap for repair of head and neck defects with negligible morbidity of the donor site.

Denervation and myotomy of muscles of the omotrapezoid triangle of the neck improve the outcomes of surgical treatment of laterocollis and torticollis subtypes of spasmodic torticollis: 58 case analysis

BACKGROUND

The main objective of this study was to analyze the outcomes of denervation and myotomy of the muscles of the omotrapezoid triangle of the neck in the treatment of 58 patients with the laterocollis and torticollis subtypes of spasmodic torticollis.

METHODS

Fifty-eight patients with the laterocollis and torticollis subtypes of spasmodic torticollis underwent 135 staged microsurgical denervations, including 25 denervation and myotomy procedures on the dystonic muscles of the omotrapezoid triangle (Tretyak's procedure). The outcome evaluation was conducted via neurological examination and the Toronto Western Spasmodic Torticollis Rating Scale (Severity subscale).

RESULTS

Tretyak's procedure allowed us to improve the outcomes of surgical treatment of the latero- and torticollis subtypes of spasmodic torticollis. Ninety-two percent of patients who underwent the denervation of the muscles of the omotrapezoid triangle moved to the group with lower ST severity-predominantly to the group with mild severity (21 patients out of 25). Tretyak's procedure appeared to be effective in 100 % of patients with the torticollis subtype of ST (15 patients out of 15) and in 80 % of patients with the laterocollis subtype of ST (8 patients out of 10).

CONCLUSIONS

Tretyak's procedure appears to be an excellent additional surgical procedure in terms of improvement of the outcomes of the "classic" Bertrand microsurgical denervation of the muscles of the neck in patients with the latero- and torticollis subtypes of spasmodic torticollis; staging of surgical denervation of muscles of the neck in the treatment of patients with the latero- and torticollis subtypes of spasmodic torticollis allows the surgeon to precisely evaluate the outcomes of previously conducted procedures, individualize the surgical approach by providing the necessary time and space to create a well-defined plan and thoroughly define the aims of further surgical denervation.

Results of ansa to recurrent laryngeal nerve reinnervation

Objective

We sought to describe the results of ansa cervicalis to recurrent laryngeal nerve (ansa-RLN) reinnervation for unilateral vocal fold paralysis.

Study Design

A chart review was performed on patients undergoing ansa-RLN reinnervation for unilateral vocal cord paralysis at a tertiary care center. Patient perceptions of preoperative and postoperative voice quality was surveyed. Acoustic and visual parameters were assessed from videostroboscopy.

Results

From a total of 25 study patients, 15 patients underwent both preoperative and postoperativ video stroboscopies. In stroboscopies within 6 months, the average improvement in overall severity, roughness, and breathiness was 69, 79, and 100 percent, respectively. In stroboscopies after 6 months, the average improvement in overall severity, roughness, and breathiness was 63, 66, and 100 percent, respectively. Postoperatively, all patients had reinnervation of the vocal fold.

Conclusions

Voice outcomes were improved in patients with preoperative and postoperative stroboscopies.

Significance

Ansa-RLN reinnervation should be considered as a treatment for unilateral vocal fold paralysis.

Modified superficial parotidectomy: Preserving both the great auricular nerve and the parotid gland fascia

Objective

To reduce the incidence of sensory deficits and Frey's syndrome by modifying the traditional superficial parotidectomy.

Study Design

After raising the skin flap, the parotid gland fascia (PGF) was elevated to form a posterior pedicle fascial flap and then was replaced after the gland removal. The great auricular nerve (GAN) that runs within the PGF was not separated, so both the GAN and the PGF were preserved. Before this modification, the GAN and PGF were examined anatomically. The complication rates in the modified and control groups were compared.

Results

1) The GAN, which runs within the thick and pycnotic PGF, trifurcates into postauricular, preauricular and lobule branches. The modification could be carried out practically based on the anatomy study. 2) Long-term sensory deficit was encountered in 13.3% of the control group, but 0% in the modified one. Frey's syndrome was suffered by 66.7% and 16.7% cases in the control and modified group respectively. The incidence of other complications was not significantly different.

Conclusion

Our modification is practical. It decreases the complications significantly. EBM rating: B-3b

The tonic oculomotor function of the cervical joint and muscle receptors

Cases of peripheral labyrinthine lesions were examined by stimulation of the cervical joint and muscle receptors. Head-chin (HC) position to one side induced compensatory oculomotor tone (ipsilateral nystagmus), which depended on the function of the horizontal canal of that side. This compensatory tone increased the duration of the optokinetic after-nystagmus (OKAN), with stripes moving contralaterally to the HC position. Isometric contraction of the muscles which rotate the HC to one side induced ipsilateral oculomotor tone (contralateral nystagmus), which depended on the function of the utricle acting in the same direction. In one case, the muscle-induced tone increased the frequency of the OKN with the slow phase in the same direction; in another, it prolonged the slow-phase pursuit interval. In the absence of a vestibular component, distortion of the OKN was induced.

Cervico-Oculo-Acoustic Syndrome in a Male with Consanguineous Parents

Background:

The cervico-oculo-acoustic syndrome comprises Klippel-Feil anomaly, sensorineural deafness and Duane's retraction syndrome. Polygenic, autosomal dominant, and X-linked inheritance have been hypothesized. The disorder has rarely been reported in males.

Case Report:

A 42-year-old male, born of consanguineous parents, presented with Duane's syndrome, mixed hearing loss, C2-C3 fusion, neck stiffness, and right facial palsy. A variety of cardiac, neurological and urogenital anomalies occurred in his relatives. The electro-oculographic studies showed impaired abduction and adduction of the right eye and impaired abduction of the left eye. Vergence, vertical eye movements and peripheral vestibular responses were normal. Somatosensory evoked potentials showed absence of the N13 peak and brainstem auditory evoked potentials bilateral delay of the I-III interpeak latencies.

Conclusions:

Consanguinity of the patient's parents, not previously reported, suggests autosomal recessive inheritance, but autosomal dominant inheritance is indicated by the family history. The pattern of the oculomotor deficit is consistent with bilateral dysplasia of the abducens nuclei with preserved internuclear neurons in the right abducens nucleus. Neurophysiological investigations revealed lower brainstem and cervical cord involvement.

The platysma myocutaneous flap

Reconstructing defects of the oral mucosa or skin of the lower one-third of the face can be accomplished by a variety of techniques. This article presents two versions of the platysma myocutaneous flap, which is a reliable, axial pattern, pedicled flap capable of providing excellent one-stage reconstruction of such defects. As discussed herein, the superiorly based and posteriorly based versions of the flap have wide application in the oral and facial region. Also provided is a review of other uses of this flap in head and neck surgery.

Clinical uses of cervical vestibular-evoked myogenic potential testing in pediatric patients

To demonstrate the feasibility and clinical significance of cervical vestibular-evoked myogenic potential (cVEMP) test in pediatric patients.Retrospective review study was conducted in a pediatric tertiary care facility. A total of 278 patients were identified with adequate data, including medical notes, results of cVEMP, and imaging studies.Among the total of 278 pediatric patients, only 3 children were not able to finish the cVEMP test successfully. In about 90% of the cases, the cVEMP test was requested to investigate a patient's hearing loss and/or vestibular complaints. Over 90% of the cVEMP tests were ordered by specialists such as pediatric otolaryngologists or otologists. Obtained cVEMP results provided useful information in clinical diagnosis and management in all cases.It is feasible to conduct cVEMP testing in children, including infants, and cVEMP testing can provide valuable information in the diagnosis and management of hearing loss and vestibular impairment. This simple and noninvasive test should be embraced by pediatric professionals.

The trigemino-cervical reflex in patients with trigeminal neuralgia

OBJECTIVES

To investigate the central trigeminal system in idiopathic trigeminal neuralgia (TN).

MATERIALS AND METHODS

Short latency responses can be recorded in sternocleidomastoid (SCM) muscles after stimulation of the trigeminal nerve (trigemino-cervical reflex). This brainstem reflex was investigated in 40 healthy subjects and in 17 patients suffering from idiopathic TN before and after therapy for 2 months with carbamazepin.

RESULTS

Before therapy, six patients presented abnormalities of SCM responses on the painful side, six patients with bilateral abnormalities, and five patients with normal responses. A significant variation in the responses after therapy was found only in the patients with unilateral abnormalities: these patients and the patients with normal reflexes before therapy also had a good response to the therapy with significant pain relief.

CONCLUSIONS

Our findings suggest that the trigemino-cervical reflex could be useful in the clinical assessment of TN prior to instituting non-surgical treatment. The bilateral location of the abnormalities in some patients seems to point to a centrally located dysfunction; therefore, this study supports the idea that mechanisms in the central nervous system may play an important role in the pathophysiology of trigeminal neuralgic pain.

[Functional reconstruction of trapezius muscle through transpositional anastomosis of C4 anterior trunk and accessory nerve]

OBJECTIVE

To investigate the feasibility of transpositional anastomosis of C4 anterior trunk and accessory nerve for functional reconstruction of the trapezius muscle so as to provide theoretical basis of repairing accessory nerve defects.

METHODS

Thirty-six adult male Sprague-Dawley rats (weighing 200-250 g) were randomly divided into the experimental group (n = 18) and control group (n = 18). The transpositional anastomosis of C4 anterior trunk and accessory nerve was performed in the left sides of experimental group; the accessory nerve was transected in the left sides of control group; and the right sides of both groups were not treated as within-subject controls. The electrophysiological and histological changes of the trapezius muscle were measured. The values of the latencies and amplitudes of compound muscle action potential (CMAP) were recorded in the experimental group at 1, 2, and 3 months; the latency delaying rate, amplitude recovery rate, and restoration rate of muscular tension were calculated. The counts of myelinated nerve fibers from distal to the anastomotic site were analyzed. The transverse area of the trapezius muscle was also measured and analyzed in 2 groups. Meanwhile, the muscles and nerves were harvested for transmission electron microscope observation in the experimental group at 1 and 3 months.

RESULTS

As time passed by, the experimental group showed increased amplitudes of CMAP, shortened latencies of CMAP, and improved muscular tension. At 3 months, the amplitude recovery rates were 63.61% +/- 9.29% in upper trapezius muscle and 73.13% +/- 11.85% in lower trapezius muscle; the latency delaying rates were 130.45% +/- 37.27% and 112.62% +/- 19.57%, respectively; and the restoration rate of muscular tension were 77.27% +/- 13.64% and 82.47% +/- 22.94%, respectively. The passing rate of myelinated nerve fibers was 82.55% +/- 5.00%. With the recovery of innervation, the transverse area of the trapezius muscle increased, showing significant differences between experimental group and control group at different time points (P < 0.05). The transmission electron microscope showed that the myotome arranged in disorder at 1 month and tended to order at 3 months.

CONCLUSION

Transpositional anastomosis of C4 anterior trunk and the accessory nerve can effectively reconstruct the function of the trapezius muscle of rats.

[Activity of bilateral posterior cricoarytenoid muscle satellite cell after denervation or reinnervation with ansa in dogs]

OBJECTIVE

To investigate the activity of bilateral posterior cricoarytenoid muscle satellite cell after denervation or reinnervation with ansa cervicalis.

METHODS

Twenty four dogs were randomly divided into 3 groups. The bilateral laryngeal recurrent nerves were cut in group one in all dogs. The bilateral laryngeal recurrent nerves were anastomosed with ansa cervicalis after incision in group two in all dogs. The dogs in group three were used as control. Nine weeks after surgery, the electromyography was used to test the regeneration of the nerve. The posterior cricoarytenoid muscles biopsy were collected. The expression of mRNA of Myogenin, Myf5, and Pax7 was assayed by realtime RT-PCR after total RNA isolation.

RESULTS

Two dogs died after surgery in incision and anastomose group. The electromyography suggested that the RLN of all dogs had denervated in the incision group and had reinnervated in the anastomose group after 9 weeks. Myogenin mRNA from RLN incision dogs PCA muscles had greater expression versus controls (Z = 1.42, P < 0.01) or anastomosed dogs (Z = 1.38, P < 0.01). Myf5 mRNA expression from RLN incision dogs PCA muscles had significant increase versus control dogs (Z = 1.66, P < 0.01) or anastomosed dogs (Z = 1.69, P < 0.01). Pax7 mRNA expression from RNL incision dogs had significant increase compared with control (Z = 1.66, P < 0.01) or anastomosed animals (Z = 1.42, P < 0.05). There was no significant difference in Myogenin (Z = 1.34, P > 0.05), Myf5 (Z = 0.54, P > 0.05) and Pax (Z = 0.54, P > 0.05) mRNA expression between controls and anastomosed animals.

CONCLUSIONS

The bilateral denervation of RLN cause significantly increasing in dog PCA muscle satellite cell proliferation and differentiation. The bilateral reinnervation of RLN cause PCA muscle satellite cell come back nonproliferative, quiescent state in dog.

[Anatomical study of the superficial cervical plexus: application to the prevention of the postoperative sensitive facial deficits]

INTRODUCTION

The cervical surgery can be complicated of postoperative facial sensory deficits, in particular in using the anterior presternocleidomastoid approach. The purpose of this study was to specify the routes and the links of nerves involved in these sensory deficits (great auricular nerve and transverse cervical nerve with the goal, to deducing, if possible, some modifications of the surgical practices to prevent the deficits.

PATIENTS

Ten dissections of the superficial cervical plexus, on preserved anatomical subjects, were made from February till May 2009. Nerves and whole superficial venous network were dissected on all along their route to be able to make several measures of distances and angles. All the data were computerized treated by spreadsheet.

RESULTS

The transverse cervical nerve appeared from the posterior edge of the sternocleidomasoid (SCM) muscle in 7.46 ± 1.81 cm s (5,1-10,0) of the clavicle, with an angle of 108.3 ± 8.15° (93-120). Its halving terminal branches was made in 2.92 ± 1.76 cm s (0,4-5,2) of the posterior edge of the SCM muscle, with an angle between these two branches of 74.0 ± 36.8° (40-120). The great auricular nerve appeared from the posterior edge of the muscle SCM in 8.96 ± 1.85 cm (6.4-12.0) of the clavicle, with an angle of 64.5 ± 23.39° (35-110), which modified secondarily to measure 39.5 ± 6.15° (27-45) in the middle of the SCM muscle. At this level, the great auricular nerve and the external jugular vein were almost parallel (1.3° of average difference) and the distance that separated them was 2.24 ± 0.79 cm (0.8-3.5).

CONCLUSION

Our study gave us a precise description of the superficial cervical plexus. All the measures allowed the establishment of the routes and the links of these structures to propose peroperating actions to prevent these facial sensory deficits.

Sonography of the normal greater occipital nerve and obliquus capitis inferior muscle

BACKGROUND

To use sonography to measure the cross-sectional area (CSA) of the greater occipital nerve (GON) and the adjacent obliquus capitis inferior muscle (OCI) in normal subjects.

METHODS

Data from 30 asymptomatic subjects between the ages of 22 and 35 were collected. CSA and circumference of the GON and CSA of OCI were measured using sonography. Interexaminer reliability analysis was performed using the intraclass correlation coefficient.

RESULTS

The CSA of the GON and OCI were 2 mm2 +/- 1 mm2 and 1.86 cm2 +/- 0.51 cm2, respectively. The average circumference of the GON was 4.8 mm +/- 1.3 mm. The interexaminer reliability of the measurements was excellent with intraclass correlation coefficient coefficients of 0.91, 0.84, and 0.73 for the GON CSA, GON circumference, and OCI CSA, respectively.

CONCLUSION

We report the normal values of the CSA of the GON and OCI. Knowledge of these normal values may facilitate the diagnosis of GON entrapment and provide outcome measures in therapeutic interventions.

Evidence of unilateral isolated utricular hypofunction

CONCLUSIONS

The findings demonstrate that an enduring unilateral utricular dysfunction, possibly together with canal hypofunction, can occur after labyrinthine disease or injury. They also suggest that unilateral, isolated utricular dysfunction - or utricle paresis - can occur, representing a novel entity in the differential diagnosis of peripheral vestibular function. The occurrence of subjective visual vertical (SVV) asymmetry in the presence of symmetric vestibular evoked myogenic potentials (VEMPs) also confirms that the information from the utricles, rather than the saccules, dominates SVV estimation.

OBJECTIVES

To determine the incidence of unilateral utricular hypofunction.

METHODS

The retrospective clinical study deals with a selection of those vestibular patients who showed pathological responses to utricle testing. Peripheral vestibular function was examined in a group of 110 patients. Utricular function was evaluated by estimation of SVV during unilateral centrifugation. Bithermal caloric testing was performed to assess unilateral semicircular canal function. Saccular function was tested by measurement of VEMPs.

RESULTS

A total of 46 patients were found with asymmetric SVV findings (p < 0.001 for healthy versus lesioned ear), but symmetric caloric responses and VEMPs. Statistical testing also verified that their SVV asymmetry factors were significantly higher than those calculated for caloric responses and VEMPs (p < 0.001).

Vestibular schwannoma with absent vestibular evoked myogenic potentials to clicks but normal ABR, caloric responses and vestibular evoked myogenic potentials to 500 Hz tone bursts

We report a case of vestibular schwannoma with absent vestibular evoked myogenic potentials (VEMPs) to clicks but normal auditory brainstem responses, caloric responses, and vestibular evoked myogenic potentials to 500 Hz tone bursts. This patient visited our clinic with complaint of sudden right hearing loss. This was the third episode of hearing loss in his right ear. Due to atypical medical history, he underwent further neuro-otological and neuroradiological examinations. Among the neurophysiological tests, only VEMPs to clicks showed abnormal findings (absent responses on the right). MRI revealed a small vestibular schwannoma in the right internal auditory meatus, which was considered to be of inferior vestibular nerve origin. This case suggested that VEMPs to clicks should still be included in the test batteries for the diagnosis of vestibular schwannoma.

The clinical reliability of vestibular evoked myogenic potentials

Vestibular evoked myogenic potential (VEMP) testing has gained popularity as a diagnostic modality in otolaryngology and audiology. To maximize the utility of this test, examiners need the availability of ideal test settings and reliable norms. We conducted a prospective study of 8 subjects with no history of neurotologic symptoms to examine the test-retest consistency of VEMP testing and to analyze the impact of stimulus type and muscle tension monitoring. All subjects underwent VEMP testing with two stimuli: a 500-Hz tone and a click. With each stimulus, testing was completed with and without monitoring of sternocleidomastoid muscle tension. All subjects participated in an initial testing session and then returned for a repeat testing session 2 to 4 weeks later. We measured the amplitude of primary waveforms P13 (first positive peak) and N23 (first negative peak) and analyzed the reliability and reproducibility of the mean amplitude asymmetry of these VEMP peaks. The P13 component of the VEMP (specificity: 86.25%) demonstrated a more stable amplitude than did the N23 component (specificity: 70.50%). Therefore, our statistical analysis of the effect of stimulus type and muscle tension monitoring on test-retest reliability was limited to the P13 waveform. We found that neither the type of stimulus nor the presence or absence of muscle tension monitoring had any statistically significant effect on amplitude asymmetry. We concluded that in VEMP testing, the P13 component was more specific than the N23 component in identifying normal subjects and that the P13 component provided consistent results across test sessions, regardless of the type of stimulus or the presence or absence of muscle tension monitoring.

An anatomical study of the arterial and nerve supply of the infrahyoid muscles

A precise knowledge of the sources of the arterial and neural supply of the sternohyoid (SH), sternothyroid (STM), and superior belly of omohyoid (OM) is of value to surgeons using the infrahyoid muscles in reconstruction procedures of the head and neck. This study was designed to define the anatomical bases of the variable sources of the arterial and neural supply of these muscles. Fourteen cadavers were unilaterally dissected in the neck region, and the arterial pedicles of these muscles were followed and accurate measurements were taken. For the SH, two arterial pedicles (superior and inferior) originated from the superior thyroid artery ST and supplied the muscle in 57.1% of cases. The inferior pedicle was absent in 42.9% of cases. As regards the STM, one arterial pedicle from the ST supplied its upper end by multiple branches in 57.1% of cases. In 14.3% of cases, branches from the inferior thyroid artery (IT) supplied the STM in addition to its supply from the ST. As regards the OM, two arterial pedicles originated from the ST and supplied its upper and lower ends in 57.1% of cases. The main artery from the ST to the superior belly of OM entered at its superior portion. The ansa cervicalis (AC) innervated the infrahyoid muscles. SH usually had a double nerve supply. In 57.1% of cases, its superior part was innervated by the nerve to the superior belly of OM. Its inferior part received branches from the AC. In 35.7% of cases, its superior part received direct branches from the AC. As regards the STM, in (71.4%) of cases, a common trunk arose from the loop and supplied the inferior part of both the SH and STM. The nerve supply to the superior belly of OM originated from the AC below the loop in 64.3% of cases. These data will be useful for preserving the neuro-vascular supply of the infrahyoid muscles during flap preparation.

Vestibular evoked myogenic potentials of children with inner ear malformations before and after cochlear implantation

CONCLUSIONS

Our results show that among the patients with inner ear malformations, there were two patients with sensory cells of sacculus and inferior vestibular neurons and at least five patients with inferior vestibular neurons only, but no patients without sensory cells and vestibular neurons, as determined on the basis of vestibular evoked myogenic potentials (VEMPs).

OBJECTIVE

The aim of this study was to investigate whether sensory cells of sacculus or inferior vestibular neurons or both are present in cochlear implant patients with inner ear malformations, particularly common cavity (CC) deformity, using VEMPs.

PATIENTS AND METHODS

Seven children with inner ear malformation who underwent cochlear implantation (CI) participated in this study. The patients had CC deformity (n=2), incomplete partition type I (n=2), incomplete partition type II (n=1), or a narrow internal auditory canal (IAC) (n=2). It was possible to record VEMPs before and after CI in three patients and not before but after CI in four patients. After surgery, VEMPs were recorded with the cochlear implant device switched both off and on.

RESULTS

Before the CI, two patients showed VEMPs and one patient showed no VEMPs, whereas in four patients no VEMPs could be recorded. All the patients showed VEMPs with the cochlear implant on.

Vestibular evoked myogenic potentials in chronic otitis media before and after surgery

CONCLUSION

The pathology of chronic otitis media (COM) could delay and reduce the energy transfer of sound to the inner ear. The significant improvement of postoperative vestibular evoked myogenic potential (VEMP) response rate and p13 latencies in the group of patients with no or negative postoperative ABG gain provided evidence that the sound energy inducing a VEMP might be different from the energy producing the auditory perception.

OBJECTIVE

To evaluate the VEMP in patients with COM before and after surgery.

SUBJECTS AND METHODS

Twenty-four subjects with unilateral COM were enrolled. A pure tone audiogram and VEMP using 500 Hz unilateral short tone-burst stimulations were recorded before and 3 months after surgery. The postoperative VEMP responses were compared with the responses before surgery and the healthy controls.

RESULTS

After surgery, the 500 Hz air-bone gap (ABG) decreased significantly and the VEMP response rate increased significantly from 41.7% to 66.7% (p<0.05, bi-test). However, both the preoperative and postoperative p13 latencies were significantly longer than those of the healthy controls (p<0.05, Wilcoxon rank-sum test). In the 18 patients whose 500 Hz ABG did not improve with surgery, the p13 latencies were significantly shorter postoperatively (p<0.05, sign test), and the response rate also improved significantly from 44.4% (8/18) to 77.8% (14/18) (p<0.05, bi-test).

Hearing and vestibular functions after plugging surgery for the posterior semicircular canal

CONCLUSIONS

Results of audiometry, caloric testing and vestibular evoked myogenic potential (VEMP) testing were hardly influenced by plugging surgery.

OBJECTIVE

To evaluate the influence of surgical plugging of the posterior semicircular canal on inner ear function in patients with benign paroxysmal positional vertigo (BPPV).

SUBJECTS AND METHODS

The subjects were five consecutive patients with intractable BPPV who underwent plugging surgery. The following functions of the inner ear were examined before and 6 months after surgery. Cochlea function was evaluated by the average hearing level of three frequencies (500, 1000 and 2000 Hz), that of the semicircular canal by canal paresis percent (CP%) in caloric testing and that of the otolith by the left-right difference ratio on VEMP testing.

RESULTS

Positional vertigo was resolved in all patients. One subject was completely deaf before and after surgery. The average hearing level did not change more than 10 dB after surgery in the other four cases. CP% did not worsen more than 10% in any case. The VEMP results after surgery did not change more than 10% from before surgery in any case.

Occipital neurostimulation-induced muscle spasms: implications for lead placement

BACKGROUND

For many headache types, occipital peripheral nerve stimulation (ONS) provides significant relief of chronic, frequent, and severe headaches. Though rarely reported, ONS may cause painful muscle spasms that make stimulator use impractical. The classic description of the technique advocates placement of the leads transversely at the level of the arch of C1 or at C1-2. At that level, the greater occipital nerve (GON) infrequently pierces the superficial fascia of the neck muscles to become superficial. However, important anatomic variability exists.

OBJECTIVE

To report placement of leads higher at the nuchal line rather than the classically recommended C1 level to avoid ONS-induced muscle spasm.

METHODS

Four interventional pain physicians independently revised ONS leads due to painful muscle stimulation. Five case reports of surgical ONS lead revision for management of ONS-induced muscle spasms are described and discussed.

RESULTS

Placement of peripheral neurostimulator leads at or above the nuchal line in these 5 cases provided good paresthesiae without causing neck muscle spasm.

CONCLUSION

Lead placement at the level of C1 or C1-2 may cause some patients to have intolerable neck/occipital spasm during neurostimulation. This is the first known published report of technical variation in the location of lead placement, at the nuchal line in a transverse fashion, for ONS. Placing ONS leads at the level of the occipital protuberance appears to eliminate ONS-induced muscle spasm while allowing good paresthesia coverage.

LIMITATIONS

Stimulation parameters vary, thus posting parameters may be misleading as muscle spasms occurred despite multiple reprogramming attempts and were a function of lead position, not program settings.

Stimulated muscle force assessment of the sternocleidomastoid muscle in humans

The aim of this study was to configure a force assessment device and determine potential testing protocols for quantitative evaluation of human neck muscles. The study design consisted of non-randomized control trials, with repeated measures; data from 12 normal subjects were obtained. Several apparatuses were designed, constructed and tested, i.e. single or short trains of supramaximal stimuli were used to activate sternocleidomastoid muscles in a seated position with strain gauges (6.2% variability with double-pulse stimulations) or in supine positions with load cells (5.2% variability with similar activation). Using a final configuration, maximum elicited peak forces were 1742 +/- 323 g for single-pulse and 3976 +/- 484 g for double-pulse stimulations (n = 12). There were no significant differences in maximum recorded peak torques between sessions per individual. Yet, detectable muscle activities were simultaneously recorded in the contralateral sternocleidomastoid muscles. This non-invasive, quantitative assessment approach has novel value for determining treatment efficacy, disease progression, and/or approach has novel value for determining determining treatment efficacy, disease progression, and/or relative distribution of muscle strength in patients with abnormal neck muscle function.

Anterior Segment Growth and Peripheral Neural Pathways in Chick

PURPOSE

To learn if peripheral nerve pathways are necessary for corneal expansion and anterior segment growth under a 12-hr light:dark cycle or for the inhibition of corneal expansion under constant light rearing.

METHODS

Recently hatched White Leghorn chicks under anesthesia received unilateral ciliary ganglionectomy (CGx), cranial cervical ganglionectomy (Sx), or section of the ophthalmic nerve (TGx), along with sham-operated and/or never-operated control cohorts. Chicks were reared postoperatively under either a 12-hr light:dark cycle or under constant light. After 2 weeks and with the chicks under anesthesia, corneal radii of curvature and diameters were obtained with a photokeratoscope, refractometry and A-scan ultrasonography were performed, and the axial and equatorial dimensions of enucleated eyes were measured with digital calipers. Corneal areas were calculated from corneal curvatures and diameters.

RESULTS

Despite the rich peripheral innervation to the eye, the selective denervations performed here exerted remarkably limited effects on corneal expansion and anterior segment development in chicks reared under either lighting condition. Ophthalmic nerve section did reverse in large part the inhibition of equatorial expansion of the vitreous chamber occurring under constant light rearing.

CONCLUSIONS

The ciliary, sympathetic, or ophthalmic peripheral nerve pathways to the eye are not required either for corneal expansion and anterior segment development under a 12-hr light:dark cycle or for the inhibition of corneal expansion under constant light rearing. The ocular sensory innervation may be a means for regulating vitreous cavity shape.

Altered trigeminal system excitability in menstrual migraine patients

To evaluate brainstem excitability in menstrual migraine (MM) patients and compare the electrophysiological parameters of the trigeminocervical reflex (TCR) during the perimenstrual (headache period) and follicular (headache-free) periods with those in healthy controls. Thirty-one patients with MM and 22 volunteer age- and sex-matched healthy women were included in the study. The TCR was studied bilaterally with stimulation of the supraorbital branch of the trigeminal nerve during the perimenstrual period and follicular phase. The electrophysiological parameters of the TCR were compared between MM patients and controls. In controls, there was no statistically significant difference in the mean reflex latencies recorded during the perimenstrual and follicular phases (P > 0.05). In MM patients, the mean reflex latencies recorded during the perimenstrual (headache period) and follicular phase (headache-free) periods were significantly different from each other and from those in controls. The latencies of MM patients during the follicular (headache-free) period were significantly longer than those of controls. Brainstem excitability differed significantly between the perimenstrual (headache period) and follicular phase (headache-free) periods in MM. Furthermore, trigeminal excitability in MM patients was significantly different from that in healthy controls in both phases of the menstrual period.

A simple method of identifying the spinal accessory nerve in modified radical neck dissection: anatomic study and clinical implications for resident training

PURPOSE

The major complication of neck dissection and surgery at the posterior triangle of the neck is the shoulder syndrome, which results from spinal accessory nerve injury. Erb's point (the great auricular nerve) and the point where the spinal accessory nerve enters the trapezius muscle are used to identify the spinal accessory nerve in the posterior nerve triangle.

MATERIALS AND METHODS

Measurements were made during unilateral neck dissections in 30 patients to identify the relationship between the spinal accessory nerve and great auricular nerve and the distance between the entrance of the accessory nerve in the trapezious and clavicle.

RESULTS

The distance between the spinal accessory nerve and Erb's point was ranging from 0 to 3.8 cm (mean 1.53 cm). The distance between the spinal accessory nerve entering the trapezious muscle and the clavicle was between 2.5 and 7.3 cm (mean 4.8 cm).

CONCLUSIONS

Since the great auricular nerve (Erb's point) represents a constantly identifiable landmark, it allows simple and reliable identification of the course of the spinal accessory nerve. Also useful, but of secondary importance in our opinion, is identifying the nerve at the point where it enters the trapezius muscle.

Surgical anatomy of the spinal accessory nerve: is the great auricular point reliable?

OBJECTIVE

The study was to exam if the great auricular point is a dependable landmark for finding the spinal accessory nerve.

DESIGN

A prospective study from January 2004 to August 2006 in a tertiary medical centre.

SETTING

A tertiary medical centre, Tzu Chi General Hospital.

METHODS

In the modified radical neck dissection, the topographic anatomy of spinal accessory was studied in 50 patients.

MAIN OUTCOME

The great auricular point (GAP) was identified and the length of sternocleidomastoid muscle (SCM) below was measured. The distance between the spinal accessory nerve and the greater auricular point was measured.

RESULTS

The ratio of the length of the SCM below the nerve exiting point to the total length of the muscle was near 0.66. The mean distance between the GAP and the accessory nerve was 0.92 cm (SD +/- 0.27).

CONCLUSIONS

The great auricular point is a reliable landmark for identification of the accessory nerve during the neck dissection.

Tympanomastoid Suture and Digastric Muscle in Cadaver and Live Parotidectomy

OBJECTIVES/HYPOTHESIS

To prove that the tympanomastoid suture (TMS) is a significantly closer and less variable anatomic landmark to the facial nerve than the posterior-superior margin of the posterior belly of the digastric muscle (PBD) in parotid surgery.

MATERIALS AND METHODS

A prospective study of 14 cadaver specimens and 22 live patients comparing the closest measured distances between the TMS and PBD to the facial nerve.

RESULTS

The mean closest distances from the TMS and PBD to the facial nerve were 1.8 (range 0-4) mm and 12.4 (range 7-17) mm, respectively (P < .05) for cadavers. The mean closest distances in live patients from the TMS and PBD to the facial nerve were 2.0 (range 0-4) mm and 10.7 (range 5-14) mm, respectively (P < .05).

CONCLUSIONS

Facial nerve identification and preservation is the key to successful parotid surgery. The TMS is a significantly closer and less variable anatomic landmark compared with the PBD both in cadaver dissection and in live patients.

Occipital neuralgia: possible failure of surgical treatment - case report

Surgical intervention in severe cases of occipital neuralgia should be considered if pharmacological and local nerve blocking treatment fail. The literature suggests two types of interventions: surgical decompression of the greater occipital nerve (GON) from the entrapment site, as a less invasive approach, and neurotomy of the nerve trunk, which results in ipsilateral sensation deficits in the GON innervated area of the skull. Due to anatomical variations in the division of the GON trunk, typical neurotomy above the line of the trapezius muscle aponeurosis (TMA) may not result in full recovery. The present study discusses a case of a female treated with GON decompression as a result of occipital neuralgia unresponsive to pharmacotherapy, who thereafter was qualified for two consecutive neurotomies due to severe relapse of pain.

Dual innervations of mylohyoid muscle: a case report

Mylohyoid and anterior belly of the digastric muscles are supplied by a branch from the inferior alveolar nerve called the mylohyoid branch. Here we present an unusual finding in a 60-year-old male cadaver in which the mylohyoid muscle is supplied by a branch from hypoglossal nerve in addition to its usual nerve supply. Hypoglossal nerve after giving superior root of the ansa cervicalis and muscular branches to thyrohyoid and geniohyoid muscles gave another branch to supply the mylohyoid muscle. Any variation in the formation and/or branching pattern of ansa cervicalis or hypoglossal nerve can cause confusion and may complicate the procedures involving this nerve such as skull base surgery, neck dissection, and anterior cervical spinal approach. Developmentally mylohyoid muscle is from the mesoderm of the first arch, therefore, must be innervated by the mandibular nerve. Hence, we report this uncommon variation based on embryology and the clinical implications.