The role of intraoperative neuromonitoring in preventing lesions of the spinal accessory nerve during functional neck dissection

Intraoperative neuromonitoring (IONM) in thyroid surgery offers a valid aid to the operator in identifying the recurrent laryngeal nerve and preserving its function. Recently, IONM has also been used in other surgeries, such as spinal accessory nerve dissection, during lymphectomy of the II, III, IV, and V laterocervical lymph nodes. The goal is the preservation of the spinal accessory nerve, whose macroscopic integrity does not always indicate its functionality. A further difficulty is the anatomical variability of its course at the cervical level. The aim of our study is to assess whether the use of the IONM helps to reduce the incidence of transient and permanent paralysis of the spinal accessory nerve, compared to "de visu" identification by the surgeon alone. In our case series, the use of the IONM reduced the incidence of transient paralysis, and no permanent paralysis was recorded. In addition, if the IONM registers a reduction in nerve potential, compared to the baseline value during surgery, it could indicate the need for early rehabilitation treatment, increasing the patients' chances of regaining function and reducing the costs of prolonged physiotherapy treatment.

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.

A randomized controlled trial of scapular exercises with electromyography biofeedback in oral cancer patients with accessory nerve dysfunction

PURPOSE

This study aims to investigate the effects of electromyography (EMG) biofeedback on scapular positions and muscle activities during scapular-focused exercises in oral cancer patients with accessory nerve dysfunction.

METHODS

Twenty-four participants were randomly allocated to the motor-control with biofeedback group (N = 12) or the motor-control group (N = 12) immediately after neck dissection. Each group performed scapular-focused exercises with conscious control of scapular orientation for 3 months. EMG biofeedback of upper trapezius (UT), middle trapezius (MT), and lower trapezius (LT) was provided in the motor-control with biofeedback group. Scapular symmetry measured by modified lateral scapular slide test; shoulder pain; active range of motion (AROM) of shoulder abduction; upper extremity function; maximal isometric muscle strength of UT, MT, and LT; and muscle activities during arm elevation/lowering in the scapular plane were evaluated at baseline and the end of the intervention.

RESULTS

After the 3-month intervention, only the motor-control with biofeedback group showed improving scapular symmetry. Although both groups did not show significant improvement in shoulder pain, increased AROM of shoulder abduction and muscle strength of the UT and MT were observed in both groups. In addition, only the motor-control with biofeedback group had improved LT muscle strength, upper extremity function, and reduced UT and MT muscle activations during arm elevation/lowering.

CONCLUSIONS

Early interventions for scapular control training significantly improved shoulder mobility and trapezius muscle strength. Furthermore, by adding EMG biofeedback to motor-control training, oral cancer patients demonstrated greater effectiveness in stabilizing scapular position, muscle efficiency, and upper extremity function than motor-control training alone.

TRIAL REGISTRATION

Institutional Review Board: This study was approved by the Chang Gung Medical Foundation Institutional Review Board (Approval No: 201901788A3. Approval Date: 2 January, 2020).

CLINICAL TRIAL REGISTRATION

This trial was registered at ClinicalTrials.gov (ClinicalTrials.gov ID: NCT04476004. Initial released Date: 16 July, 2020).

Adherence to a shoulder dysfunction physical therapy protocol after neck dissection with accessory nerve preservation in head-and-neck cancer patients: An uncontrolled clinical trial

Objective

Accessory nerve (AN) manipulation or resection during neck dissection (ND) generates accessory nerve shoulder dysfunction (ANSD). The aim of the present study was to assess adherence to a supervised physiotherapy protocol and subsequent changes in the functionality scores of patients with ASND with accessory nerve (AN) preservation.

Methods

This study consisted of an uncontrolled clinical trial was carried out at the Department of Head and Neck Surgery and Otorhinolaryngology at the A.C. Camargo Cancer Center, comprising progressive isotonic and isometric strengthening of scapular stabilizer muscles. In patients with head-and-neck cancer underwent ND with AN preservation and patients with ANSD. Shoulder range of motion (ROM), middle trapezius, lower trapezius, rhomboid and anterior serratus muscle strength, pain, and quality of life (QoL) were measured in the pre-operative and 1^st and 3^rd post-operative months. There were included patients over 18 years old, with head-and-neck cancer who underwent ND with AN preservation and patients with ANSD.

Results

A total of 55 patients were evaluated, with a mean age of 53 (±13.23). Significant improvement in the functionality scores of almost all variables between pre- and post- physiotherapy was observed. Most patients (70.9%) adhered and completed the protocol, obtaining significantly greater ROM abduction (P = 0.009) and lower trapezius strength (P = 0.011) than partially performing patients.

Conclusion

When performed completely, the proposed physiotherapy protocol can minimize loss in muscle movements and strength, especially limited after ND. The results indicate that the proposed protocol is safe and has the potential to reduce ANSD.

Accessory Nerve Anatomy in Anterior and Posterior Cervical Triangle: A Fresh Cadaveric Study

Objective

To understand the variations and normal course of the accessory nerve (CNXI) to help more accurate and confident neck dissection.

Methods

The course of the CNXI in the neck, its relationship to the surrounding anatomic structures and the factors affecting its course were investigated.

Results

A total of 100 neck dissections were performed on 50 fresh cadavers. Eleven division variations were observed at the anterior triangle. The location of CNXI at the posterior border of the sternocleidomastoid muscle (PBSCM) was investigated and the ratio between the distance from the mastoid apex (MAA) to CNXI at the PBSCM and the distance from MAA to the posterior border where the PBSCM is attached to the clavicle increased as height of the subject increased (p<0.05).

Conclusion

It must be kept in mind that it is better to search for CNXI in taller subjects more inferiorly at the posterior border of the sternocleidomastoid muscle.

Lower cranial nerve syndromes: a review

The purpose of this paper is to provide a comprehensive review encompassing the syndromes associated with the lower cranial nerves (LCNs). We will discuss the anatomy of some of these syndromes and the historical contributors after whom they were named. The LCNs can be affected individually or in combination, since the cranial nerves at this level share their courses through the jugular foramen and hypoglossal canal and the extracranial spaces. Numerous alterations affecting them have been described in the literature, but much remains to be discovered on this topic. This paper will highlight some of the subtle differences among these syndromes. Symptoms and signs that have localization value for LCN lesions include impaired speech, deglutition, sensory functions, alterations in taste, autonomic dysfunction, neuralgic pain, dysphagia, head or neck pain, cardiac or gastrointestinal compromise, and weakness of the tongue, trapezius, or sternocleidomastoid muscles. To assess the manifestations of LCN lesions correctly, precise knowledge of the anatomy and physiology of the area is required. Treatments currently used for these conditions will also be addressed here. Effective treatments are available in several such cases, but a precondition for complete recovery is a correct and swift diagnosis.

Exposure of the External Carotid Artery Through the Posterior Neck Triangle, Cadaveric Surgical Simulation: 2-Dimensional Operative Video

The external carotid artery (ECA) is a robust extracranial donor used for high-flow cerebrovascular bypass procedures. It is usually exposed through the anterior triangle of the neck and may be used to revascularize recipients in the anterior or upper posterior cerebral circulations. However, when a high-flow bypass to the posterior circulation is indicated, oftentimes the patient needs to be put in the prone position (or variants thereof). In such situations, accessing the ECA through the anterior triangle of the neck can be challenging. Therefore, using a technique that enables the surgeon to expose the ECA through a posterior approach could be helpful.1 Although we have not yet encountered a case requiring this type of exposure and bypass, this cadaveric surgical simulation video demonstrates the surgical technique of exposing the ECA through the posterior triangle of the neck (as a cadaveric video, no patient consent was necessary). Briefly, this technique involves an inferolateral extension of the muscular stage of the far-lateral approach and exposing the ECA through a plane developed between the parotid gland and the posterior belly of the digastric muscle. The technical details of this technique are described. Also, relevant anatomic information regarding the safety measures taken to protect adjacent neurovascular structures are discussed.

Microvascular decompression with partial occipital condylectomy in a case of pediatric spasmodic torticollis

Spasmodic torticollis is a rare, neurologic disorder that is caused by abnormal nerve compression of the 11th cranial nerve by blood vessels or bony protrusions. It is typically treated pharmacologically and, if necessary, with surgical intervention. We report a unique case of spasmodic torticollis in a 15-year-old female that involved abnormal compression of the left 11th cranial nerve (CN) by the left vertebral artery, displaced by a hypertrophic left occipital condyle. After treatment with Botox was unsuccessful, the patient was treated with microvascular decompression and occipital condylectomy that adequately relieved the abnormal compression of CN XI. Mild symptoms persisted, and the patient underwent a partial section of the sternocleidomastoid muscle 1 year later, after which torticollis symptoms resolved.

A Method for Cranial Nerve XI Silencing During Surgery of the Foramen Magnum Region: Technical Case Report

BACKGROUND AND IMPORTANCE

Skull base surgery involves the microdissection and intraoperative monitoring of cranial nerves, including cranial nerve XI (CN XI). Manipulation of CN XI can evoke brisk trapezius contraction, which in turn may disturb the surgical procedure and risk patient safety. Here we describe a method for temporarily silencing CN XI via direct intraoperative application of 1% lidocaine.

CLINICAL PRESENTATION

A 41-yr-old woman presented with symptoms of elevated intracranial pressure and obstructive hydrocephalus secondary to a hemangioblastoma of the right cerebellar tonsil. A far-lateral suboccipital craniotomy was performed for resection of the lesion. During the initial stages of microdissection, vigorous trapezius contraction compromised the course of the operation. Following exposure of the cranial and cervical portions of CN XI, lidocaine was applied to the course of the exposed nerve. Within 3 min, trapezius electromyography demonstrated neuromuscular silencing, and further manipulation of CN XI did not cause shoulder movements. Approximately 30 min after lidocaine application, trapezius contractions returned, and lidocaine was again applied to re-silence CN XI. Gross total resection of the hemangioblastoma was performed during periods of CN XI inactivation, when trapezius contractions were absent.

CONCLUSION

Direct application of lidocaine to CN XI temporarily silenced neuromuscular activity and prevented unwanted trapezius contraction during skull base microsurgery. This method improved operative safety and efficiency by significantly reducing patient movement due to the unavoidable manipulation of CN XI.

ASSESSMENT OF THE RESULTS OF ACCESSORY TO SUPRASCAPULAR NERVE TRANSFER

Objective

Nerve transfers are an alternative in the reconstruction of traumatic brachial plexus injuries. In this study, we report the results of branchial plexus reconstruction using accessory to suprascapular nerve transfer.

Methods

Thirty-three patients with traumatic brachial plexus injuries underwent surgical reconstruction with accessory to suprascapular nerve transfers. The patients were divided into groups in which surgery was performed either within 6 months after the injury or more than 6 months after the injury. Results were assessed using the Constant score.

Results

There was no significant difference between the groups with respect to the Constant score.

Conclusion

Accessory to suprascapular nerve transfer was not an efficient method for recovering active ROM or strength in the shoulder. However, it effectively improved pain control and shoulder stability. Level of evidence II, Retrospective Study.

A prospective analysis of prevalence of metastasis in levels IIB and V neck nodes in patients with operable oral squamous cell carcinoma

OBJECTIVES

The present study was designed to know and analyze the prevalence of pathological involvement of level IIB and V neck nodes in operable oral cavity squamous cell carcinomas.

MATERIALS AND METHODS

All treatment naïve, willing biopsy proven patients of age group 18-70 years with oral cavity squamous cell carcinomas undergoing surgery from May 2015 to December 2016 in a single tertiary care Institute were prospectively analyzed for level IIb and V involvement.

RESULTS

A total of 199 patients met the selection criteria of the study. Most common site was buccal mucosa, majority were cT2 lesions and 90% underwent Modified neck dissection. 63% of patients had pN0 disease. The rate of involvement of level II b and V nodes was 3% and was associated with higher T size, disease burden in proximal basin and lymphovascular invasion. There was no skip metastasis to level IV. Only one patient had skip metastasis to levels V and IIB each.

CONCLUSION

To conclude our data strongly supports omission of level IIb and level V nodal dissection routinely in patients with cT1 and T2 buccal cancers. However, a randomized controlled study to evaluate the morbidity as well as recurrence pattern between the selective and super-selective approach is warranted.

Accessory nerve distribution for aesthetic botulinum toxin injections into the upper trapezius muscle: anatomical study and clinical trial : Reproducible BoNT injection sites for upper trapezius

PURPOSE

The descending part of the trapezius muscle is clinically associated with neck pain and aesthetic applications. The innervation of the trapezius muscle is not well described in the medical literature for clinicians. The aim of study was to analyze the perforating branch pattern of the accessory nerve in the descending part of the trapezius muscle with the aim of describing the most efficient and reproducible BoNT injection sites for aesthetic treatment of shoulder contouring.

METHODS

Twenty-six specimens (five male and eight female) from embalmed Korean cadavers were used in this study. The trapezius muscle was dissected scrupulously and then reflected to enable examination of the locations of the perforating points. The thickness of trapezius muscle was measured in 13 volunteers using a diagnostic ultrasonography system. BoNT was injected into the trapezius muscle bilaterally. Injections were performed at 6 points separated by 2 cm. The muscle thicknesses were measured three times using ultrasonography: before the injection and at 4 and 12 weeks after the injection.

RESULTS

The dense arborization of the perforating accessory nerve branches was confined mostly to section b (66.7%, 54/81) and section c (33.3%, 27/81). The mean muscle thickness at 4 and 12 weeks consistently decreased 0.68-0.63 cm  in conventional method and 0.65-0.61 cm in new method (NDM) respectively (right and left).

CONCLUSION

To optimize the outcome of BoNT injection, we recommended injecting into six points separated by 2 cm in sections b and c of the upper trapezius muscle. It is significant that it is easier to apply to anyone than to apply unstructured techniques.

Cervical Vestibular Evoked Myogenic Potentials (cVEMPs) Evoked by Air-Conducted Stimuli in Patients with Functional Neck Dissection

OBJECTIVE

Cervical vestibular-evoked myogenic potentials (cVEMPs) are short-latency vestibulocollic reflexes. The damage on any point of the vestibulocollic reflex pathway could affect the cVEMPs. Whether neck dissection has an effect on the sacculocollic pathway, and consequently on cVEMPs, remains unexplored. The aim of this study was to evaluate the cVEMP findings in patients with functional neck dissection without vestibular symptoms.

PATIENTS AND METHODS

This cross-sectional study design, 20 patients who had undergone unilateral neck dissection with sparing of the accessory nerve, SCM and internal jugular vein, were included. The response rates (%), cVEMPs parameters such as the prestimulus background EMG [Root mean square (RMS)] activity (μV), P13 and N23 peak latencies (ms), interpeak (N23-P13) interval (ms), scale and non-scale interpeak (N23-P13) amplitudes (μV) were compared between the groups. Amplitude asymmetry ratio (AAR) was calculated.

RESULTS

Twenty patients (14 males and 6 females), age was between 38 and 79 years were included in the study. All of the patients had clear cVEMPs on the NOS, whereas 18/20 (90%) patients had on the NDS. P13 and N23 peak latency of the NDS were found to be significantly longer than the NOS (P = 0.01). There was no significant difference in N23-P13 interpeak interval between two sides (P > 0.05). There was a negative correlation between P13 peak latency and post-operative time (P = 0.042; R = ‑0.484). Scale and non-scale N23-P13 interpeak amplitudes of the NDS were found to be significantly lower than the NOS (P = 0.03). Mean AAR was found as 0.28 ± 0.16 (0.08-0.76). Seven patients (35%) had abnormal amplitude asymmetry. RMS values, were statistically and significantly lower in NDS compared to NOS (P = 0.01). However, no correlation was observed between the RMS values and peak latency and peak amplitude values (P > 0.05).

CONCLUSIONS

cVEMP testing is an easy-to-apply, non-invasive, painless, and recordable test that can be used for evaluations of SAN and SCM function for patients undergoing neck dissection. After neck dissection, VEMP abnormalities can be detected. However, further studies are needed to indicate whether these abnormalities originate within the vestibular system and are due to pathologies originating from the SANs and SCMs. In addition, preoperative and postoperative studies are needed to better guide the clinical application of cVEMP testing.

Nerve and vein preserving neck dissections for oral cancers: a prospective evaluation of spinal accessory nerve function and internal jugular vein patency following treatment

Nerve and vein preserving modification of the radical neck dissection is commonly used in the management of oral squamous cell cancers. There is limited literature addressing nerve function and vein patency following treatment. We prospectively analysed 65 patients with nerve conduction study using surface electromyography at baseline, 1 month and 6 months post-surgery and colour Doppler of the internal jugular vein at baseline and 1 month post-surgery. We also studied functional outcomes of nerve sparing with arm abduction test and Neck Dissection Quality of Life questionnaire. There was a statistically significant increase in mean latency of motor action potential and decrease in the mean amplitude of the motor action potential following surgery, suggesting nerve dysfunction. Following surgery, there was a significant decrease in the diameter of the vein as well as an increase in the velocity of blood flow; there was partial thrombus in 5% of individuals. In conclusion, even though nerve dysfunction compromised shoulder abduction, vein dysfunction rarely resulted in any significant clinical impact.

17β-Estradiol Inhibites Tumor Necrosis Factor-α Induced Apoptosis of Human Nucleus Pulposus Cells via the PI3K/Akt Pathway

Background

Tumor necrosis factor-α (TNF-α) has been widely known to induce degeneration of nucleus pulposus cells (NPCs). 17β-estradiol (17β-E2) has been broadly proven for its function of suppressing cell apoptosis. The aim of this study is to explore whether 17β-E2 protects apoptosis of human NPCs induced by TNF-α via the PI3K/AKT pathway.

Material/Methods

NPCs were divided into four groups: control, TNF-α (100 ng/mL), TNF-α (100 ng/mL) with pretreated 17β-E2 (10 um/L), TNF-α (100 ng/mL) with pretreated 17β-E2 (10 um/L) and MK2206 (10 um/L, inhibitor of the PI3K/AKT pathway). Flow cytometry was used to measure the apoptotic incidence. Inverted phase-contrast microscopy was used to accomplish the morphological observation for apoptosis of treated cells. Additionally, Cell Counting Kit 8 (CCK-8) assay was used to detected cell proliferation. Western blot and quantitative real-time PCR (qRT-PCR) were applied to explore the expression of pro-caspase-3, caspase-3/p17, cleaved PARP, PARP, Akt, and phospho-Akt (p-Akt).

Results

First, inverted phase-contrast microscopy, CCK-8, and flow cytometry showed that TNF-α induced marked apoptosis, which was abolished by 17β-E2. Furthermore, Western blot and qRT-PCR showed that 17β-E2 protects TNF-α which can induced apoptosis by upregulating p-Akt, whereas Akt was essentially constant. Our data revealed that p-Akt expression peaked at 24 hours in a time-dependent manner (0–48 hours) after treating with TNF-α; and the p-Akt expression generally increased in a time-dependent manner (0–48 hours) after treating with TNF-α and 17β-E2.

Conclusions

17β-E2 is shown to protect NPCs against TNF-α induced apoptosis by upregulating p-Akt in the PI3K/AKT pathway. 17β-E2 generally increases expression of p-Akt.

The unique axon trajectory of the accessory nerve is determined by intrinsic properties of the neural tube in the avian embryo

The accessory nerve is a cranial nerve, composed of only motor axons, which control neck muscles. Its axons ascend many segments along the lateral surface of the cervical spinal cord and hindbrain. At the level of the first somite, they pass ventrally through the somitic mesoderm into the periphery. The factors governing the unique root trajectory are unknown. Ablation experiments at the accessory nerve outlet points have shown that somites do not regulate the trajectory of the accessory nerve fibres. Factors from the neural tube that may control the longitudinal pathfinding of the accessory nerve fibres were tested by heterotopic transplantations of an occipital neural tube to the cervical and thoracic level. These transplantations resulted in a typical accessory nerve trajectory in the cervical and thoracic spinal cord. In contrast, cervical neural tube grafts were unable to give rise to the typical accessory nerve root pattern when transplanted to occipital level. Our results show that the formation of the unique axon root pattern of the accessory nerve is an intrinsic property of the neural tube.

Internal Jugular Vein Duplication: Review and Classification

Internal jugular vein duplication (IJVD) is a rare phenomenon. Twenty-one such instances in 18 individuals have been reported to date. We report an intra-operative case of unilateral IJVD in a 32-year-old male, who was operated for cancer of gingivobuccal sulcus. We have reviewed the published literature and have proposed a classification scheme in order to make future reporting systematic. The condition has been classified into type A, B and C based on their morphology. About 75 % of the reported cases are of Type A. Type C is the most complex of all the duplications. Though IJVD is physiologically inconsequential, it has clinical implications. Percutaneous catheterisation of the vein could be hazardous in all cases, but more so in type B and C duplications. As with any anomaly, the risk of accidental injury increases during surgical procedures. It is important to document findings of this anomaly in order to understand its anatomy and implications in a better way.

Aberrant innervation of the sternocleidomastoid muscle by the transverse cervical nerve: a case report

Two aberrant rami originating from the right transverse cervical nerve and innervated the midportion of the sternocleidomastoid muscle (SM) were detected during routine cadaver dissection. Although SM is commonly innervated by the accessory nerve, as well as by cervical nerves, it is likely to be innervated additionally by other nerves such as hypoglossal nerve, ansa cervicalis, facial or external laryngeal nerve. Some considerations as regards the possible composition of the aberrant rami of the transverse cervical nerve detected in the current study, as well as the relevant literature is discussed.

Evolutionary and developmental understanding of the spinal accessory nerve

The vertebrate spinal accessory nerve (SAN) innervates the cucullaris muscle, the major muscle of the neck, and is recognized as a synapomorphy that defines living jawed vertebrates. Morphologically, the cucullaris muscle exists between the branchiomeric series of muscles innervated by special visceral efferent neurons and the rostral somitic muscles innervated by general somatic efferent neurons. The category to which the SAN belongs to both developmentally and evolutionarily has long been controversial. To clarify this, we assessed the innervation and cytoarchitecture of the spinal nerve plexus in the lamprey and reviewed studies of SAN in various species of vertebrates and their embryos. We then reconstructed an evolutionary sequence in which phylogenetic changes in developmental neuronal patterning led towards the gnathostome-specific SAN. We hypothesize that the SAN arose as part of a lamprey-like spinal nerve plexus that innervates the cyclostome-type infraoptic muscle, a candidate cucullaris precursor.

Intracisternal cranial root accessory nerve schwannoma associated with recurrent laryngeal neuropathy

Intracisternal accessory nerve schwannomas are very rare; only 18 cases have been reported in the literature. In the majority of cases, the tumor origin was the spinal root of the accessory nerve and the tumors usually presented with symptoms and signs of intracranial hypertension, cerebellar ataxia, and myelopathy. Here, we report a unique case of an intracisternal schwannoma arising from the cranial root of the accessory nerve in a 58-year-old woman. The patient presented with the atypical symptom of hoarseness associated with recurrent laryngeal neuropathy which is noted by needle electromyography, and mild hypesthesia on the left side of her body. The tumor was completely removed with sacrifice of the originating nerve rootlet, but no additional neurological deficits. In this report, we describe the anatomical basis for the patient's unusual clinical symptoms and discuss the feasibility and safety of sacrificing the cranial rootlet of the accessory nerve in an effort to achieve total tumor resection. To our knowledge, this is the first case of schwannoma originating from the cranial root of the accessory nerve that has been associated with the symptoms of recurrent laryngeal neuropathy.

Schwannoma of the spinal accessory nerve: a case report

We are reporting a rare case of a schwannoma which originated from the cervical portion of the spinal accessory nerve, which was located in the left posterior triangle of the neck and did not have any neurological deficit, which was diagnosed by the Magnetic Resonance Imaging (MRI) scan and confirmed histopathologically after surgery.

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.