Trapezius muscle innervation from the spinal accessory nerve and branches of the cervical plexus

A detailed review of the spinal accessory nerve and its anatomical variations with cadaveric illustration

The spinal accessory nerve, considered part of the eleventh cranial nerve, provides motor innervation to sternocleidomastoid and trapezius. A comprehensive literature review and two cadaveric dissections were undertaken. The spinal accessory nerve originates from the spinal accessory nucleus. Its rootlets unite and ascend between the denticulate ligament and dorsal spinal rootlets. Thereafter, it can anastomose with spinal roots, such as the McKenzie branch, and/or cranial roots. The spinal accessory nerve courses intracranially via foramen magnum and exits via jugular foramen, within which it usually lies anteriorly. Extracranially, it usually crosses anterior to the internal jugular vein and lies lateral to internal jugular vein deep to posterior belly of digastric. The spinal accessory nerve innervates sternocleidomastoid, receives numerous contributions in the posterior triangle and terminates within trapezius. Its posterior triangle course approximates a perpendicular bisection of the mastoid-mandibular angle line. The spinal accessory nerve contains sensory nociceptive fibres. Its cranial nerve classification is debated due to occasional non-fusion with the cranial root. Surgeons should familiarize themselves with the variable course of the spinal accessory nerve to minimize risk of injury. Patients with spinal accessory nerve injuries might require specialist pain management.

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.

Functional Anatomy and Biomechanics of the Craniovertebral Junction

The craniovertebral junction (CVJ) involves the atlas, axis, and occiput along with the atlanto-occipital and atlantoaxial joints. The anatomy and neural and vascular anatomy of the junction render the CVJ unique. Specialists treating disorders that affect the CVJ must appreciate its intricate anatomy and should be well versed in its biomechanics. This first article in a three-article series provides an overview of the functional anatomy and biomechanics of the CVJ.

Anatomy and clinical application of suprascapular nerve to accessory nerve transfer

BACKGROUND

Loss of motor function in the trapezius muscle is one complication of radical neck dissection after cutting the accessory nerve (AN) during surgery. Nerve repair is an effective method to restore trapezius muscle function, and includes neurolysis, direct suture, and nerve grafting. The suprascapular nerve (SCN) and AN are next to each other in position. The function of the AN and SCN in shoulder elevation and abduction movement is synergistic. SCN might be considered by surgeons for AN reanimation.

AIM

To obtain anatomical and clinical data for partial suprascapular nerve-to-AN transfer.

METHODS

Ten sides of cadavers perfused with formalin were obtained from the Department of Human Anatomy, Histology and Embryology, Peking University Health Science Center. The SCN (n = 10) and AN (n = 10) were carefully dissected in the posterior triangle of the neck, and the trapezius muscle was dissected to fully display the accessory nerve. The length of the SCN from the origin of the brachial plexus (a point) to the scapular notch (b point) and the distance of the SCN from the origin point (a point) to the point (c point) where the AN entered the border of the trapezius muscle were measured. The length and branches of the AN in the trapezius muscle were measured. A female patient aged 55 years underwent surgery for partial SCN to AN transfer at Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology. The patient suffered from recurrent upper gingival cancer. Radical neck dissection was performed on the right side, and the right AN was removed at the intersection between the nerve and the posterior border of the SCM muscle. One-third of the diameter of the SCN was cut off, and combined epineurial and perineurial sutures were applied between the distal end of the cut-off fascicles of the SCN and the proximal end of the AN without tension. Both subjective and objective evaluations were performed before, three months after, and nine months after surgery. For the subjective evaluation, the questionnaire included the Neck Dissection Impairment Index (NDII) and the Constant Shoulder Scale. Electromyography was used for the objective examination. Data were analyzed using t tests with SPSS 19.0 software to determine the relationship between the length of the SCN and the linear distance. A P value of < 0.05 was considered as statistically significant.

RESULTS

The whole length of the AN in the trapezius muscle was 16.89 cm. The average numbers of branches distributed in the descending, horizontal and ascending portions were 3.8, 2.6 and 2.2, respectively. The diameter of the AN was 1.94 mm at the anterior border of the trapezius. The length of the suprascapular nerve from the origin of the brachial plexus to the scapular notch was longer than the distance of the suprascapular nerve from the origin point to the point where the accessory nerve entered the upper edge of the trapezius muscle. The amplitude of trapezius muscle electromyography indicated that both the horizontal and ascending portions of the trapezius muscle on the right side had better function than the left side nine months after surgery. The results showed that the right-sided supraspinatus and infraspinatus muscles did not lose more function than the left side.

CONCLUSION

Based on anatomical data and clinical application, partial suprascapular nerve-to-AN transfer could be achieved and may improve innervation of the affected trapezius muscle after radical neck dissection.

Trapezius Motor Evoked Potentials From Transcranial Electrical Stimulation and Transcranial Magnetic Stimulation: Reference Data, Characteristic Differences and Intradural Motor Velocities in Horses

Reason for Performing Study

So far, only transcranial motor evoked potentials (MEP) of the extensor carpi radialis and tibialis cranialis have been documented for diagnostic evaluation in horses. These allow for differentiating whether lesions are located in either the thoraco-lumbar region or in the cervical myelum and/or brain. Transcranial trapezius MEPs further enable to distinguish between spinal and supraspinal located lesions. No normative data are available. It is unclear whether transcranial electrical stimulation (TES) and transcranial magnetic stimulation (TMS) are interchangeable modalities.

Objectives

To provide normative data for trapezius MEP parameters in horses for TES and TMS and to discern direct and indirect conduction routes by neurophysiological models that use anatomical geometric characteristics to relate latency times with peripheral (PCV) and central conduction velocities (CCV).

Methods

Transcranial electrical stimulation-induced trapezius MEPs were obtained from twelve horses. TES and TMS-MEPs (subgroup 5 horses) were compared intra-individually. Trapezius MEPs were measured bilaterally twice at 5 intensity steps. Motoneurons were localized using nerve conduction models of the cervical and spinal accessory nerves (SAN). Predicted CCVs were verified by multifidus MEP data from two horses referred for neurophysiological assessment.

Results

Mean MEP latencies revealed for TES: 13.5 (11.1–16.0)ms and TMS: 19.7 (12–29.5)ms, comprising ∼100% direct routes and for TMS mixed direct/indirect routes of L:23/50; R:14/50. Left/right latency decreases over 10 > 50 V for TES were: –1.4/–1.8 ms and over 10 > 50% for TMS: –1.7/–3.5 ms. Direct route TMS-TES latency differences were 1.88–4.30 ms. 95% MEP amplitudes ranges for TES were: L:0.26–22 mV; R:0.5–15 mV and TMS: L:0.9 – 9.1 mV; R:1.1–7.9 mV.

Conclusion

This is the first study to report normative data characterizing TES and TMS induced- trapezius MEPs in horses. The complex trapezius innervation leaves TES as the only reliable stimulation modality. Differences in latency times along the SAN route permit for estimation of the location of active motoneurons, which is of importance for clinical diagnostic purpose. SAN route lengths and latency times are governed by anatomical locations of motoneurons across C2-C5 segments. TES intensity-dependent reductions of trapezius MEP latencies are similar to limb muscles while MEP amplitudes between sides and between TES and TMS are not different. CCVs may reach 180 m/s.

Predictive modelling of level IIb lymph node metastasis in oral squamous cell carcinoma

The aim of the present study was to examine the conditions, characteristics, and risk factors of level IIb lymph node metastases in oral squamous cell carcinoma and to formulate surgical criteria for level IIb lymph node dissection. We analyzed clinical and pathological records for 541 oral squamous carcinoma patients in relation to level IIb metastasis. Univariate and multivariate analyses were performed to detect risk factors for level IIb lymph node metastasis; a predictive model was built based on multivariate analysis and tested in a validation group. Univariate and multivariate analyses using the training group indicated that level IIa metastasis and Lymphovascular permeation (LVP) were two independent risk factors for level IIb lymph node metastasis. This model was built and tested in a validation group, the area under the curve being 0.697 (P < .0.001). The model's sensitivity was 66.7% and specificity was 77.4%. Nomogram incorporating validated variables was developed for level IIb metastasis prediction. Expected survival probabilites were analysed to specify significance of model's variable on patients' overall survival and recurrence. Level IIb dissection should be performed in patients with level IIa metastasis and LVP. However, thorough consideration of the oncologic safety of omitting level IIb dissection is compulsory.

Deep Cervical Plexus Block for Neck and Shoulder Pain Due to Myofascial Pain: A Randomized Clinical Trial

OBJECTIVES

Myofascial pain is one of the most common causes of regional pain with no definitive treatment. This randomized clinical trial was conducted to assess the efficacy of deep cervical plexus block versus placebo injection (sham block) for the treatment of myofascial neck and shoulder pain in terms of analgesic consumption and pain during a follow-up period of 2 weeks after the block.

MATERIALS AND METHODS

Patients were randomly divided into 2 groups. Group I (block) received deep cervical plexus block and group II (placebo) received normal saline. A total of 66 patients were included in the study, 34 patients in the block group and 32 patients in the placebo group.

RESULTS

Two weeks after the intervention, the average pain duration was significantly lower in the block group: 1.38±1.39 versus 5.25±1.72 for the block and placebo groups, respectively (P<0.0001). Pain intensity was significantly less in the block group such that 2.9% of patients in the block group had severe pain compared with 53.1% of patients in the placebo group (P<0.0001). Two weeks after receiving the block, the mean opioid consumption calculated as tramadol equivalent was 21.1±44.2 mg compared with 166.1±118.8 mg for the block and placebo groups, respectively. Multivariate analysis showed that patients with a longer history of pain had a higher pain score after 2 weeks. The possibility of recovery is affected by pain duration as patients with a history of chronic pain were least affected by the block.

DISCUSSION

This technique could be an alternative to pharmacological and other nonpharmacological treatments for myofascial pain.

Spinal accessory neuropathy in patients with chronic trapezius myofascial pain syndrome

Background

Myofascial pain syndrome is a common musculoskeletal problem affecting the trapezius muscle. The aim was to assess the presence of spinal accessory neuropathy in patients with unilateral chronic trapezius myofascial pain syndrome.

Results

The study included 25 patients with unilateral chronic trapezius myofascial pain syndrome and 20 apparently healthy volunteers as the control group. There was a significantly delayed spinal accessory nerve latency on the symptomatic side in comparison to either asymptomatic side (P = 0.014) and control group (P = 0.001). Compound muscle action potential amplitude did not significantly differ between the symptomatic side versus the asymptomatic side and control group. Delayed spinal accessory nerve latency was present in seven patients (28%) and reduced compound muscle action potential amplitude in one of them (4%). The needle electromyography of the upper trapezius muscle revealed neuropathic motor units and incomplete interference pattern in the patient who showed reduced compound muscle action potential amplitude. Abnormal rest potentials were absent in all patients. Individually, seven patients (28%) had electrophysiological evidence of spinal accessory neuropathy, but only one (4%) of them had clinical evidence of spinal accessory neuropathy. Patients with abnormal electrophysiological findings had longer duration of complaint and more severe pain.

Conclusions

Spinal accessory neuropathy is common among patients with chronic trapezius myofascial pain syndrome. It could contribute to increased pain severity of myofascial pain syndrome. Electrodiagnosis is a good modality for identifying subclinical spinal accessory neuropathy.

Dry needling as a novel intervention for cervicogenic somatosensory tinnitus: a case study

Tinnitus is defined as conscious perception of sound in the absence of a corresponding external stimulus. A condition that affects 10 - 15% of the adult population, tinnitus may be caused by an interaction between the somatosensory and auditory system, more formally known as somatosensory tinnitus. Cervicogenic somatosensory tinnitus is a subgroup of somatosensory tinnitus involving anatomical structures and physiological mechanisms associated with the cervical spine. A limited number of studies have reported inconsistent outcomes for treating cervicogenic somatosensory tinnitus with conservative treatment strategies such as manual therapy and exercise. However, dry needling is a skilled, manual therapy intervention that has recently gained popularity among the physical therapy profession that may be useful for both evaluating and treating the condition. The following case report describes the use of dry needling to evaluate and treat a patient with cervical somatosensory tinnitus and concurrent cervicogenic headaches. Physical therapy that targeted the muscles of the upper cervical spine with dry needling resulted in a meaningful reduction in cervicogenic somatosensory tinnitus, and the improvements persisted at 1-year follow-up. Further research, including randomized control trials, is warranted to fully determine the potential of dry needling to treat cervicogenic somatosensory tinnitus.

ANALYSIS OF FATTY DEGENERATION OF THE TRAPEZIUS MUSCLE AFTER USE OF ACCESSORY NERVE

Objective:

To investigate, through magnetic resonance imaging, the occurrence of fatty degeneration of the trapezius in adult patients undergoing nerve transfer procedure, using the spinal accessory nerve.

Methods:

A total of 13 patients meeting the criteria of unilateral brachial plexus injury and more than one year of postoperative care after nerve transfer surgery underwent an MRI scan of the trapezius. A T1-weighted 3D sequence was used, with the IDEAL technique using 8.0 mm cut thickness, 8.0 mm cut spacing, TR of 100 ms, TE of 3.45 ms, flip angle of 10 degrees, 20 cuts, on the sagittal plane. The images of the upper, transverse and lower parts of the trapezius muscle were then classified according to the degree of fatty degeneration, compared with the contralateral side, using the Goutallier score.

Results:

For the upper trapezius there was a change of the degeneration state in 23% (p = 0.083), for the transverse section there was a change in 84.6% (p = 0.003), for the lower one there was a change in 92.3% (p = 0.002).

Conclusion:

The upper trapezius did not undergo significant degeneration after transfer. The lower and transverse trapezius suffered fatty degeneration in most patients, indicating severe functional impairment. Level of Evidence IV, Case series.

Preoperative Evaluation of Iatrogenic Spinal Accessory Nerve Palsy: What Is the Place for Electrophysiological Testing?

PURPOSE

Electrophysiological testing has been used for the early diagnosis of iatrogenic spinal accessory nerve palsy in clinical practice. However, the presence of low-amplitude compound action potential in 70% to 90% of the patients suffering from iatrogenic nerve transection was reported in several studies. We have encountered the same issue and made minor modifications to the methods of electrophysiological testing. The purpose of this study was to retrospectively evaluate the reliability of our modified electrophysiological testing as preoperative examination in patients receiving surgical revision.

METHODS

In this study, we compared preoperative electrophysiological testing results with intraoperative diagnosis in the 24 patients with iatrogenic spinal accessory nerve palsy who were referred to our hospital from 2009 to 2018.

RESULTS

During operation, 20 patients were diagnosed with neurotmesis and the remaining 4 patients were found axonotmesis depending on the results of surgical exploration and intraoperative electrophysiological examination. Six of the 20 patients with neurotmesis demonstrated a low-amplitude compound muscle action potential of the upper trapezius during preoperative electrophysiological testing. Needle electromyography revealed voluntary motor unit potentials in 8 of the 20 patients. Meanwhile, concomitant great auricular nerve or dorsal scapular nerve injuries were preoperatively revealed in 7 of 24 patients.

CONCLUSIONS

The rate of low-amplitude compound muscle action potentials in these patients suffering from spinal accessory nerve neurotmesis was about 30% with our modified electrophysiological testing. We should be aware of this pitfall before surgical nerve repair. Furthermore, electrophysiological testing is an informative preoperative examination revealing the concomitant nerve injuries.

Optimal Trapezius Electrophysiological Recording Site

BACKGROUND

Various active recording electrode positions for the trapezius motor nerve conduction study have been suggested.

OBJECTIVE

To determine the optimal recording site of the trapezius muscles in a spinal accessory nerve conduction study.

DESIGN

Retrospective descriptive study.

SETTING

Department of physical medicine and rehabilitation in a tertiary clinic center.

PARTICIPANTS

Thirty-four patients between 33 and 82 years of age with preoperative head and neck cancer (68 upper and middle trapezius muscles).

INTERVENTIONS

Analysis of compound muscle action potentials (CMAPs) of upper and middle trapezius.

MAIN OUTCOME MEASUREMENTS

CMAP latency and amplitudes were obtained at five and four recording points with constant intervals on the horizontal line of the upper and middle trapezius, respectively.

RESULTS

The maximum CMAP amplitude of the upper trapezius was (mean ± SD) 8.5 ± 1.4 mV with the recording at the midpoint between the C7 spinous process and the lateral margin of the acromion. The maximum CMAP amplitude of the middle trapezius was 4.2 ± 1.4 mV, recorded on the horizontal line at the junction of the middle and lateral thirds between the root of the scapular spine and the vertebral spinous process.

CONCLUSION

The optimal recording site in motor nerve conduction study of the trapezius is the midpoint between the C7 spinous process and the acromion for the upper trapezius, and the junction of middle and lateral thirds of the line between the root of scapular spine and the vertebral spine for the middle trapezius.

Human motor unit characteristics of the superior trapezius muscle with age-related comparisons

Current understanding of human motor unit (MU) control and aging is mostly derived from hand and limb muscles that have spinal motor neuron innervations. The aim here was to characterize and test whether a muscle with a shared innervation supply from brainstem and spinal MU populations would demonstrate similar age-related adaptations as those reported for other muscles. In humans, the superior trapezius (ST) muscle acts to elevate and stabilize the scapula and has primary efferent supply from the spinal accessory nerve (cranial nerve XI) located in the brainstem. We compared electrophysiological properties obtained from intramuscular and surface recordings between 10 young (22-33 yr) and 10 old (77-88 yr) men at a range of voluntary isometric contraction intensities (from 15 to 100% of maximal efforts). The old group was 41% weaker with 43% lower MU discharge frequencies compared with the young (47.2 ± 9.6 Hz young and 26.7 ± 5.8 Hz old, P < 0.05) during maximal efforts. There was no difference in MU number estimation between age groups (228 ± 105 young and 209 ± 89 old, P = 0.33). Furthermore, there were no differences in needle detected near fiber (NF) stability parameters of jitter or jiggle. The old group had lower amplitude and smaller area of the stimulated compound muscle action potential and smaller NF MU potential area with higher NF counts. Thus, despite age-related ST weakness and lower MU discharge rates, there was minimal evidence of MU loss or compensatory reinnervation.NEW & NOTEWORTHY The human superior trapezius (ST) has shared spinal and brainstem motor neuron innervation providing a unique model to explore the impact of aging on motor unit (MU) properties. Although the ST showed higher MU discharge rates compared with most spinally innervated muscles, voluntary strength and mean MU rates were lower in old compared with young at all contraction intensities. There was no age-related difference in MU number estimates with minimal electrophysiological evidence of collateral reinnervation.

Schwannomatosis of the Spinal Accessory Nerve: A Case Report

Schwannomatosis is a distinct syndrome characterized by multiple peripheral nerve schwannomas that can be sporadic or familial in nature. Cases affecting the lower cranial nerves are infrequent. Here, the authors present a rare case of schwannomatosis affecting the left spinal accessory nerve. Upon genetic screening, an in-frame insertion at codon p.R177 of the Sox 10 gene was observed. There were no identifiable alterations in NF1, NF2, LZTR1, and SMARCB1. This case demonstrates a rare clinical presentation of schwannomatosis in addition to a genetic aberration that has not been previously reported in this disease context.

Ultrasound in the management of iatrogenic spinal accessory nerve palsy at the posterior cervical triangle area

INTRODUCTION

The purpose of this study was to evaluate the application of ultrasound in the management of iatrogenic spinal accessory nerve palsy at the posterior cervical triangle area.

METHODS

In this retrospective study, we compared ultrasonographic results with intraoperative findings in patients with iatrogenic spinal accessory nerve palsy during the time period from 2014 to 2018 at our hospital.

RESULTS

Eleven patients were included. Ultrasound detected nerve transections in 9 patients and continuities in 2 patients. The ultrasonographic results were consistent with the intraoperative findings. Furthermore, ultrasound was able to accurately reveal lesion location in 8 of 9 patients with nerve transections.

DISCUSSION

Ultrasound provides direct images about nerve lesions contributing to the diagnosis of iatrogenic spinal accessory nerve palsy at the posterior cervical triangle area and also reveals lesion location, assisting in formulating suitable surgical plans preoperatively. We recommend that ultrasound be integrated into the preoperative evaluation. Muscle Nerve 59:64-69, 2019.

Comparison of hospital based and home based exercise on quality of life, and neck and shoulder function in patients with spinal accessary nerve injury after head and neck cancer surgery

OBJECTIVES

The purpose of this study was to compare the effects of hospital-based and home-based exercise programs on quality of life (QOL) and neck and shoulder function of patients who underwent head and neck cancer (HNC) surgery.

METHODS

This clinical trial included 40 patients with neck and shoulder dysfunction after HNC. The exercise program included range of motion (ROM) exercises, massage, stretching, and strengthening exercises. Twenty patients who were assigned to the hospital-based exercise group performed physical therapy for 40 min three times a week for four weeks, and the remaining 20 patients were assigned to the home-based group. The European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire (EORTC QLQ-C30), the EORTC Head and Neck Questionnaire (EORTC QLQ-H&N), the Neck and Shoulder Disability Index (NDI), ROM, and numeric rating scale (NRS) were assessed before and after the exercise program. The program consisted of a 10-minute ROM to the neck and shoulder, a 10-minute massage, and 15 min of progressive resistance exercises, followed by a five-minute stretching exercise.

RESULTS

There were statistically significant differences in the changes of neck and shoulder disability index (p < .05). Additionally, there were significant differences in neck extension and rotation ROM and NRS in the hospital-based group compared with the home-based group (p < .05). QOL was not significantly different between the two groups.

CONCLUSIONS

Home-based exercise was effective for improving QOL, shoulder function, and pain relief. Hospital-based exercise had better effects on physical function of the neck and shoulder and reduced pain.

New insights into the pathophysiology of fasciculations in amyotrophic lateral sclerosis: An ultrasound study

OBJECTIVE

To describe the fasciculation pattern in ALS and to analyse its clinical and pathophysiological significance.

METHODS

Ultrasound of 19 muscles was performed in 44 patients with a recent diagnosis (<90 days) of ALS. The number of fasciculations was recorded in each muscle and the muscle thickness and strength were additionally measured in limb muscles. A subgroup of patients were electromyographically assessed.

RESULTS

US was performed in 835 muscles and EMG was available in 263 muscles. US detected fasciculations more frequently than EMG. Fasciculations were widespread, especially in upper limbs onset patients and in the cervical region. Fasciculations' number inversely associated with ALSFR-R and body mass index (BMI) and directly with BMI loss and upper motor neuron (UMN) impairment. Our statistical model suggest that fasciculations increase with the initial lower motor neuron (LMN) degeneration, reach their peak when the muscle became mildly to moderately weak, decreasing afterwards with increasing muscle weakness and atrophy.

CONCLUSIONS

Our study suggests that both UMN and LMN degeneration trigger fasciculations causing BMI loss. The degree of LMN impairment could account for differences in fasciculations' rates within and between muscles.

SIGNIFICANCE

In ALS, fasciculations could explain the link between hyperexcitability and BMI loss.

Cervical plexus block

Cervical plexus blocks (CPBs) have been used in various head and neck surgeries to provide adequate anesthesia and/or analgesia; however, the block is performed in a narrow space in the region of the neck that contains many sensitive structures, multiple fascial layers, and complicated innervation. Since the intermediate CPB was introduced in addition to superficial and deep CPBs in 2004, there has been some confusion regarding the nomenclature and definition of CPBs, particularly the intermediate CPB. Additionally, as the role of ultrasound in the head and neck region has expanded, CPBs can be performed more safely and accurately under ultrasound guidance. In this review, the authors will describe the methods, including ultrasound-guided techniques, and clinical applications of conventional deep and superficial CPBs; in addition, the authors will discuss the controversial issues regarding intermediate CPBs, including nomenclature and associated potential adverse effects that may often be neglected, focusing on the anatomy of the cervical fascial layers and cervical plexus. Finally, the authors will attempt to refine the classification of CPB methods based on the target compartments, which can be easily identified under ultrasound guidance, with consideration of the effects of each method of CPB.

Unilateral Straight Hair-A Symptom of Acquired Horner's Syndrome in a Neonate

A multicystic tumor of the right neck was detected in a girl at 29 weeks of gestation by fetal ultrasound and magnetic resonance imaging (MRI). The baby was delivered by cesarean section at week 37 of gestation. The newborn adapted well, with minimal compromise of breathing and drinking. Postnatal ultrasound and MRI revealed a cervical lymphangioma measuring 60.5 × 60.6 × 41.2 mm. We performed subtotal resection of the tumor when the girl was 34 days. As a complication of surgical resection, the girl developed ipsilateral Horner's syndrome. In the postoperative period, her curled hair turned straight at the side of the head affected by Horner's syndrome. At the age of 2.5 years, ultrasonic imaging revealed the presence of three cysts measuring 3 mm in diameter each. Horner's syndrome had improved, and the texture of the girl's hair had become curly again on both sides.

Oncologic safety of cervical nerve preservation in neck dissection for head and neck cancer

BACKGROUND

Although the functional merits of preserving cervical nerves in neck dissection for head and neck cancer have been reported, the oncologic safety has not yet been determined. Therefore, the purpose of this study was to evaluate the safety of cervical nerve preservation.

METHODS

A retrospective chart review was performed on patients with head and neck cancer who had been treated by neck dissection between 2009 and 2014 at Kyoto Medical Center. Management of cervical nerves and clinical results were analyzed.

RESULTS

A total of 335 sides of neck dissection had been performed in 222 patients. Cervical nerves were preserved in 175 neck sides and resected in 160 sides. The 5-year overall survival (OS) rate calculated by the Kaplan-Meier method was 71%. The 5-year neck control rate was 95% in cervical nerve preserved sides and 89% in cervical nerve resected sides.

CONCLUSION

Preserving cervical nerves in neck dissection is oncologically safe in selected cases.

Fracture of the Clavicle following Radical Neck Dissection and Reconstruction Using Pectoralis Major Myocutaneous Flap Accompanied by Postoperative Radiotherapy

Fracture of the clavicle following radical neck dissection (RND) and/or radiotherapy is a rare complication. Several causes of fracture of the clavicle after treatment of head and neck cancer were postulated in previous reports. We present a case of fracture of the clavicle after treatment of squamous cell carcinoma of the tongue. An 81-year-old Japanese woman underwent RND, subtotal glossectomy, reconstruction using a pectoralis major myocutaneous flap (PMMCF), and postoperative radiotherapy (50.4 Gy). One month after the primary treatment, fracture of the clavicle occurred. It was thought that muscular dynamic factor and reduction of blood supply in the clavicle associated with RND and PMMCF were the causes of the fracture. We have to recognize the occurrence of this complication and try to reduce the factors related to the complication.

The Glasgow Coma Scale and evidence-informed practice: a critical review of where we are and where we need to be

AIMS AND OBJECTIVES

This paper aims to critically consider the evidence since the Glasgow Coma Scale was first launched, reflecting on how that evidence has shaped practice. It illustrates the lack of clarity and consensus about the use of the tool in practice and draws upon existing evidence to determine the route to clarity for an evidence-informed approach to practice.

BACKGROUND

The Glasgow Coma Scale has permeated and influenced practice for over 40 years, being well-established worldwide as the key tool for assessing level of consciousness. During this time, the tool has been scrutinised, evaluated, challenged and re-launched in a plethora of publications. This has led to an insight into the challenges, and to some extent the opportunities, in using the Glasgow Coma Scale in practice but has also resulted in a lack of clarity.

DESIGN

This is a discursive paper that invites readers to explore and arrive at a more comprehensive understanding of the Glasgow Coma Scale in practice and is based on searches of Scopus, Web of Knowledge, PubMed, Science Direct and CINAHL databases.

RESULTS

While the Glasgow Coma Scale has been rivalled by other tools in an attempt to improve upon it, a shift in practice to those tools has not occurred. The tool has withstood the test of time in this respect, indicating the need for further research into its use and a clear education strategy to standardise implementation in practice.

CONCLUSION

Further exploration is needed into the application of painful stimuli in using the Glasgow Coma Scale to assess level of consciousness. In addition, a robust educational strategy is necessary to maximise consistency in its use in practice.

RELEVANCE TO CLINICAL PRACTICE

The evidence illustrates inconsistency and confusion in the use of the Glasgow Coma Scale in practice; this has the potential to compromise care and clarity around the issues is therefore necessary.

Sternocleidomastoid innervation from an aberrant nerve arising from the hypoglossal nerve: a prospective study of 160 neck dissections

BACKGROUND

Anatomical variants of the spinal root of the accessory nerve and cervical plexus are well known but other variants are exceptionally rare.

METHODS

A prospective study of 160 selective neck dissections was undertaken following an index case, where a presumed C1 nerve (travelling with the hypoglossal nerve) was found to innervate sternocleidomastoid (SCM). A search was subsequently made for this variant while not compromising the neck dissection surgery itself. Eight cases could not be included due to metastatic disease precluding safe dissection in this area. A nerve stimulator was used to confirm the motor supply to SCM.

RESULTS

This nerve variant was found in 4/160 necks (2.5 %). In all cases, it originated directly from the hypoglossal nerve and stimulation resulted in isolated SCM contraction. No accessory nerve anomalies were found.

CONCLUSION

This finding adds to the knowledge of variants in this area. Meticulous dissection and preservation of all nerves, where possible, is important for optimising functional outcomes following surgery.

Quantification of Trapezius Muscle Innervation During Neck Dissections: Cervical Plexus Versus the Spinal Accessory Nerve

OBJECTIVES

Despite increasing use of selective, nerve-sparing surgical techniques during neck dissections, the reported rate of postoperative paralysis of the trapezius muscle is still high. The aim of the study is to measure and compare motor inflow to the trapezius muscle, in order to better understand the peripheral neuroanatomy.

METHODS

Intraoperative nerve monitoring (electroneurography) in patients undergoing routine neck dissection (n=18). The innervation of the 3 functional parts of the trapezius muscle was mapped and quantified through compound muscle action potentials.

RESULTS

In 18/18 (100%) of the patients, the spinal accessory nerve (SAN) innervated all parts of the trapezius muscle. In 7/18 (39%) of the patients, an active motor branch from the cervical plexus was detected, equally distributed to all functional parts of the trapezius muscle, at levels comparable to the SAN.

CONCLUSIONS

Compared to the SAN, branches from cervical plexus provide a significant amount of neural input to all parts of the trapezius muscle. Intraoperative nerve monitoring can be used in routine neck dissections to detect these branches, which may be important following surgical injury to the SAN.

Division of the spinal accessory nerve in the anterior triangle: a prospective clinical study

The anatomical relation between the spinal accessory nerve and internal jugular vein is well documented, but other variants of the nerve, including the contributions of the cervical plexus to supply motor fibres to the trapezius, are less well known. We have previously described an anatomical variant in which the spinal accessory nerve divided before entering the sternocleidomastoid, and the inferior trunk passed directly under it to supply the trapezius. We now present a prospective study of 133 neck dissections (excluding radical dissections) in which a meticulous search was made for the variant in the anterior triangle of the neck during operation. We found it in 3 necks (2%). One of the 3 patients had a bilateral neck dissection but it was found on one side only, and in 2 cases it communicated with the cervical plexus. In all 3, stimulation of the inferior division resulted in contraction of the trapezius while the upper division was found to supply the sternocleidomastoid only. The finding of this variant, which was more common than first thought, highlights the need for meticulous dissection of the nerve before it enters the sternocleidomastoid to ensure that, when present, the inferior branch is preserved to minimise potential postoperative shoulder dysfunction. Further research including a cadaveric study is needed to understand this important variant more fully.

Innervation of the lower third of the sternocleidomastoid muscle by the ansa cervicalis through the C1 descendens hypoglossal branch: a previously unreported anatomical variant

We describe a previously unreported anatomical variant (found during a routine neck dissection) in which the lower third of the sternocleidomastoid was innervated by the C1 branch of the ansa cervicalis (descendens hypoglossi).

Expanding what is known of the anatomy of the spinal accessory nerve

The spinal accessory nerve (SAN) is classically considered a motor nerve innervating the sternocleidomastoid and trapezius muscles. Its anatomical relevance derives from the high prevalence of lesions following head and neck surgeries. As expected, trapezius weakness and atrophy are the most common findings; however, it is also commonly accompanied by pain and other sensory deficits that have no clear explanation, suggesting other functions. We have recently seen two patients presenting with an unrecognized sign, that is, subclavicular/pectoral asymmetry secondary to the SAN lesion. Retrospectively, we reviewed other patients with similar findings in our case series and in the literature. We discuss the anatomical connections of the SAN with the superficial cervical plexus and propose an explanation for this finding. Of the 41 patients in our series, we identified this sign in all who had preoperative photographs. New insights on the anatomy and connections of the SAN may account for the diversity of symptoms and signs presented following an operative intervention as well as the variability of its severity.

Identification of three anatomical patterns of the spinal accessory nerve in the neck by neurophysiological mapping

Background

In spite of preservation of the accessory nerve there is still considerable proportion of patients with partial nerve damage during modified radical neck dissection (MRND).

Methods

The nerve was identified during the surgery and its branches for the trapezius muscle mapped with nerve monitor.

Results

The accessory nerve was mapped during 74 hemineck dissections and three patterns were identified. In type 1 nerve exits at the posterior end of the sternocleidomastoid muscle (SCm) and then it enters the level V (66%). In type 2 the nerve for trapezius muscle branches off before entering the SCm (22%). In type 3 the nerve exits at the posterior part of the SCm and it joins to the cervical plexus (12%). The nerve than exits this junction more medially as a single trapezius branch.

Conclusions

The description of three anatomical patterns in level II and V could help preserving the trapezius branch during MRND.

Changes in H reflex and neuromechanical properties of the trapezius muscle after 5 weeks of eccentric training: a randomized controlled trial

Trapezius muscle Hoffman (H) reflexes were obtained to investigate the neural adaptations induced by a 5-wk strength training regimen, based solely on eccentric contractions of the shoulder muscles. Twenty-nine healthy subjects were randomized into an eccentric training group ( n = 15) and a reference group ( n = 14). The eccentric training program consisted of nine training sessions of eccentric exercise performed over a 5-wk period. H-reflex recruitment curves, the maximal M wave (Mmax), maximal voluntary contraction (MVC) force, rate of force development (RFD), and electromyographic (EMG) voluntary activity were recorded before and after training. H reflexes were recorded from the middle part of the trapezius muscle by electrical stimulation of the C3/4 cervical nerves; Mmax was measured by electrical stimulation of the accessory nerve. Eccentric strength training resulted in significant increases in the maximal trapezius muscle H reflex (Hmax) (21.4% [5.5–37.3]; P = 0.01), MVC force (26.4% [15.0–37.7]; P < 0.01), and RFD (24.6% [3.2–46.0]; P = 0.025), while no significant changes were observed in the reference group. Mmax remained unchanged in both groups. A significant positive correlation was found between the change in MVC force and the change in EMG voluntary activity in the training group ( r = 0.57; P = 0.03). These results indicate that the net excitability of the trapezius muscle H-reflex pathway increased after 5 wk of eccentric training. This is the first study to investigate and document changes in the trapezius muscle H reflex following eccentric strength training.

High division of the spinal accessory nerve and communication with a C2 branch of the cervical plexus: a previously unreported anatomical variant

Anatomical variations of the spinal accessory nerve are well known. We describe a previously unreported variant in which the nerve divided high in level II after crossing the internal jugular vein and before entering the sternomastoid muscle. Both branches were joined by a communication from the C2 cervical root. We discuss the clinical implications of this finding.

Measurement of the trapezius muscle volume: A new assessment strategy of shoulder dysfunction after neck dissection for the treatment of head and neck cancers

BACKGROUND

The purpose of this study was to determine the actual degree of shoulder muscle change and its relation to symptoms after neck dissection for head and neck cancers.

METHODS

Forty-two patients who underwent unilateral neck dissection were selected. Data obtained from each subject were trapezius muscle volume ratio and a Shoulder Disability Questionnaire (SDQ) score. Patients who had undergone neck dissection with spinal accessory nerve (SAN) preservation were compared with those who had received radical neck dissection. The preservation group was further separated into subgroups by the extent of neck dissection.

RESULTS

Trapezius muscle volume ratio was higher and SDQ score was significantly lower in the SAN preservation group compared to the radical neck dissection group. However, the SAN preservation subgroups did not differ from each other. In addition, a good correlation between the muscle volume ratio and SDQ score was observed.

CONCLUSION

With trapezius muscle volume ratio, clinicians may be able to diagnose shoulder dysfunction after neck dissection. Further research on the subject is warranted. This suggests a novel strategy for assessing the degree of shoulder dysfunction.

Motor innervation of the trapezius muscle: Intraoperative motor conduction study during neck dissection

OBJECTIVES

To evaluate the motor input from the spinal accessory nerve (SAN) and the branches of the cervical plexus in an intraoperative motor nerve conduction study measuring motor action potentials by direct stimulation of the exposed nerve during neck dissection.

METHODS

The entire length of the SAN and the contributions from the upper cervical plexus were preserved. Compound muscle action potentials were measured for each part of the trapezius muscle on stimulation of the SAN, C2, C3, and C4 nerves.

RESULTS

With stimulation of the spinal nerve, evoked responses were obtained from all 24 patients in the descending, transverse, and ascending trapezius muscle. C2 contributions were noted in 2 out of 24 patients; however, no patient revealed responses in all three parts of the muscle. C3 contributions were seen in 11 out of 24 patients, supplying all three parts of the muscle in 8 patients, and C4 contributions were noted in 20 out of 24 patients, supplying all three parts of the muscle in 16 of them.

CONCLUSIONS

The SAN provided the most consistent motor input to the trapezius muscle. The C2, C3, and C4 nerves also provided motor input to the trapezius muscle; however, they were either inconsistently present or, when present, irregularly innervated the three parts of the trapezius muscle.

Spinal accessory neuropathy in patients with chronic neck pain

AIM: To assess the presence of spinal accessory neuropathy in patients with chronic neck pain.

METHODS: Patients with pain either regional or focal in the neck or shoulders for at least 6 mo (chronic neck pain) were recruited randomly from the Rheumatology and Rehabilitation Outpatient Clinic at the Faculty of Medicine-Suez Canal University. Two groups were compared: 30 patients with chronic neck pain with mean age (36.97 ± 12.45 years) and 10 apparently healthy controls. Trapezius muscle examination including inspection and range of motion both active and passive was performed. A full clinical neurological examination was carried out to exclude peripheral neuropathy and motor neuron disease. According to the subject’s type of work, cases were categorized into labor-intensive and non-labor intensive tasks. A nerve conduction study (NCS) was performed on spinal accessory nerves at both sides for all patients and controls. Parameters including latencies and amplitudes of compound motor action potential (CMAP) were compared with the chronicity of neck pain using the neck disability score. This cross sectional study was carried in the Rheumatology and Rehabilitation Department, at Suez Canal University Hospital, Ismailia, Egypt.

RESULTS: Physical examination revealed that 80% of cases had spinal trapezius muscle spasm. Restricted neck motion was present in 16.6% of cases. No one suffered from muscle wasting or weakness. Pain was bilateral in 18 patients (60%), localized to the right side in six patients (20%) and localized to the left side in six patients (20%). The causes of neck pain in the patients studied were nonspecific, due to physical stresses, cervical spondylosis and mild cervical disc herniation. Mean disease duration in patients with labor-intensive tasks was (3.9 ± 2.1 years), which was longer than that in patients with non-labor intensive tasks (3.1 ± 1.9 years); however, this difference was statistically insignificant. Spinal accessory NCSs were performed while subjects were in sitting positions and relaxed with naturally suspended arms to minimize muscular movement. The results of electrophysiological studies revealed that mean right and left latencies of the spinal accessory nerve were 2.96 ± 0.69 ms, 2.98 ± 0.61 ms in the patient group and 2.44 ± 0.38 ms, 2.33 ± 0.36 ms in control group respectively. These differences were statistically significant with P = 0.028 and 0.006 respectively. Spinal accessory NCS showed normal CMAP amplitude in both patients and controls. Comparing the results of the neck disability index (NDI) to different characteristics in patients with chronic neck pain, showed that patients with labor-intensive work had a higher NDI score mean (34.7 ± 9.5) compared to those with non-labor-intensive work, with significant statistical difference (P = 0.011). In addition, mean NDI scores were higher in males, and patients aged over 40 years and this difference was statistically significant (P = 0.007 and P = 0.009 respectively). Correlation studies between right and left spinal accessory nerve latencies and disability percent calculated using the NDI revealed a positive correlation. Moreover, there was a positive correlation between age and disability percent.

CONCLUSION: This study demonstrates electrophysiological evidence of demyelination in a significant proportion of patients with chronic cervical pain.

Impact of neck dissection on scapular muscle function: a case-controlled electromyographic study

OBJECTIVE

To assess the dynamic activity of scapular muscles in patients with accessory nerve dysfunction after neck dissection surgery, compared with both their unaffected side and with age- and sex-matched controls.

DESIGN

A case-control investigation.

SETTING

Physiotherapy department of a hospital.

PARTICIPANTS

Two groups of 10 participants were recruited. One group consisted of neck dissection patients with demonstrated clinical signs of accessory nerve injury. The second group was composed of matched healthy individuals.

INTERVENTIONS

Surface electromyographic activity of the upper trapezius, middle trapezius, rhomboid major, and serratus anterior muscles was compared dynamically during scapular strengthening exercises.

MAIN OUTCOME MEASURES

Electromyographic activity comparisons were made between the neck dissection affected side, the neck dissection unaffected side, and the matched healthy control side. Raw data and data expressed as a percentage of maximal voluntary isometric contraction were compared.

RESULTS

The neck dissection affected side demonstrated significantly less upper trapezius and middle trapezius muscle activity compared with the neck dissection unaffected side and matched control group. The neck dissection unaffected side had significantly less upper trapezius muscle activity than the matched control group.

CONCLUSIONS

Trapezius muscle activity is significantly reduced in accessory nerve shoulder dysfunction as a result of neck dissection, both in the affected and unaffected sides. This needs to be considered in the rehabilitation of this patient group.

Invisible scar endoscopic thyroid surgery by the dorsal approach: importance of the spinal accessory nerve

PURPOSE

With about 100,000 surgeries per year in Germany, thyroid operations count among the most common procedures performed in general and endocrine visceral surgery. Twentieth century technological development gives the opportunity to perform thyroid surgery without leaving visible scar like conventional approaches do. This study is part of the work on the videoendoscopic retro-auricular access to the thyroid gland using the EndoCATS method by Schardey and Schopf. To avoid possible complications with the spinal accessory nerve (SAN), like irritation or injury of the nerve as happened during a feasibility study, a systematic study of the surgical anatomy at the nerve's entry to the posterior cervical triangle is performed especially in relation to the EndoCATS operation method.

METHODS

Sixty-one neck regions in fifty-three specimens were examined at the anatomical institute of Munich to investigate the course of the SAN relative to the anatomic landmarks tip of mastoid bone, sternal notch, and posterior border of the sternocleidomastoid muscle together with the SAN's course variants at its entry to the posterior cervical triangle. The results were then statistically analyzed.

RESULTS

From this analysis, we derived a simple method to predict the course of the SAN preoperatively and offer a new approach to protect the SAN during EndoCATS surgery. Additionally, we found a significant difference of the SAN's course between male and female specimens.

CONCLUSION

The EndoCATS method can be a safe alternative to conventional thyroid surgery, but the SAN is at risk during the surgery procedure. Here we give feasible solutions to eliminate the SAN-problem performing EndoCATS thyroid surgery.

Physiotherapy for accessory nerve shoulder dysfunction following neck dissection surgery: a literature review

BACKGROUND

Neck dissection is an operation that can result in accessory nerve injury. Accessory nerve shoulder dysfunction (ANSD) describes the pain and impaired range of motion that may occur following neck dissection. The aim of this review was to establish the level of evidence for the effectiveness of physiotherapy in the postoperative management of ANSD.

METHODS

A literature search of physiotherapy and ANSD using Medline, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Physiotherapy Evidence Database (PEDro), and Cochrane Library databases was undertaken.

RESULTS

Physiotherapy has been shown to be well tolerated in this patient group following surgery. However, few studies exist as to the effect of physiotherapy on ANSD.

CONCLUSIONS

There is a need for research to investigate the effects of early, appropriate physiotherapy on the development of ANSD following neck dissection surgery. Such a study has the potential to improve the functional outcome and quality of life in this patient group, and ultimately to promote best practice guidelines for management.

Complications of head and neck cancer surgery - prevention and management

Surgery continues to retain a pivotal role in head and neck cancer in terms of the management of both the index tumour and potential or proven cervical disease. This review considers the specific complications of surgery in this anatomical region and, on the basis of the available evidence, describes both their management and prevention.

Study of the cervical plexus innervation of the trapezius muscle

OBJECT

There is conflicting and often anecdotal evidence regarding the potential motor innervation of the trapezius muscle by cervical nerves, with most authors attributing such fibers to proprioception. As knowledge of such potential motor innervations may prove useful to the neurosurgeon, the present study aimed to elucidate this anatomy further.

METHODS

Fifteen adult cadavers (30 sides) underwent dissection of the posterior triangle of the neck and harvesting of cervical nerve fibers found to enter the trapezius muscle. Random fibers were evaluated histologically to determine fiber type (that is, motor vs sensory axons).

RESULTS

In addition to an innervation from the spinal accessory nerve, the authors also identified cervical nerve innervations of all trapezius muscles. For these innervations, 3 sides were found to have fibers derived from C-2 to C-4, 2 sides had fibers derived from C-2 to C-3, and 25 sides had fibers derived from C-3 to C-4. Fibers derived from C-2 to C-4 were classified as a Type I innervation, those from C-2 to C-3 were classified as a Type II innervation, and those from C-3 to C-4 were classified as a Type III innervation. Immunohistochemical analysis of fibers from each of these types confirmed the presence of motor axons.

CONCLUSIONS

Based on the authors' study, cervical nerves innervate the trapezius muscle with motor fibers. These findings support surgical and clinical experiences in which partial or complete trapezius function is maintained after injury to the spinal accessory nerve. The degree to which these nerves innervate this muscle, however, necessitates further study. Such information may be useful following nerve transfer procedures, denervation techniques for cervical dystonia, or sacrifice of the spinal accessory nerve due to pathological entities.

Prevention of complications in neck dissection

BACKGROUND

The neck dissection has remained a pivotal aspect of head and neck cancer management for over a century. During this time its role has expanded from a purely therapeutic option into an elective setting, in part promoted by efforts to reduce its morbidity.

OBJECTIVES

This review will consider the potential complications of neck dissection and on the basis of the available evidence describe both their management and prevention.

CONCLUSION

Although the neck dissection continues to provide clinicians with a method of addressing cervical disease, its reliability and safety can only be assured if surgeons remain cognisant of the potential complications and aim to minimise such morbidity by appropriate management in the peri-operative period.