Surgical and radiological perspectives for the spinal accessory nerve passing through a fenestrated internal jugular vein: case series and literature review.

The preservation of the spinal accessory nerve represents a key goal in head and neck oncologic surgery during selective neck dissection. This study aims to illustrate the anatomical variants of the XI cranial nerve, delving into the relationship between the spinal nerve and the internal jugular vein, as well as the surgical implications. Two cases of patients who underwent oncologic surgery with neck dissection are described. Both cases found the spinal accessory nerve passing through the fenestration of the internal jugular vein. Alongside this case series, an independent literature review was conducted using the Medline and PubMed databases. In the majority of cases (67% - 96%), the spinal accessory nerve traces a lateral course to the internal jugular vein. Less frequently, the XI cranial nerve courses medial to the internal jugular vein. More rarely, as described in this case series, the nerve crosses through the fenestration of the vein (0.48% - 3.3%).

Advancing glenohumeral dysplasia treatment in brachial plexus birth injury: the end-to-side spinal accessory to suprascapular nerve transfer technique.

PURPOSE: Brachial plexus birth injury (BPBI) is a common injury with the spectrum of disease prognosis ranging from spontaneous recovery to lifelong debilitating disability. A common sequela of BPBI is glenohumeral dysplasia (GHD) which, if not addressed early on, can lead to shoulder dysfunction as the child matures. However, there are no clear criteria for when to employ various surgical procedures for the correction of GHD. METHODS: We describe our approach to correcting GDH in infants with BPBIs using a reverse end-to-side (ETS) transfer from the spinal accessory to the suprascapular nerve. This technique is employed in infants that present with GHD with poor external rotation (ER) function who would not necessitate a complete end-to-end transfer and are still too young for a tendon transfer. In this study, we present our outcomes in seven patients. RESULTS: At presentation, all patients had persistent weakness of the upper trunk and functional limitations of the shoulder. Point-of-care ultrasounds confirmed GHD in each case. Five patients were male, and two patients were female, with a mean age of 3.3 months age (4 days-7 months) at presentation. Surgery was performed on average at 5.8 months of age (3-8.6 months). All seven patients treated with a reverse ETS approach had full recovery of ER according to active movement scores at the latest follow-up. Additionally, ultrasounds at the latest follow-up showed a complete resolution of GHD. CONCLUSION: In infants with BPBI and evidence of GHD with poor ER, end-to-end nerve transfers, which initially downgrade function, or tendon transfers, that are not age-appropriate for the patient, are not recommended. Instead, we report seven successful cases of infants who underwent ETS spinal accessory to suprascapular nerve transfer for the treatment of GHD following BPBI.

Weightlifting Induced Spinal Accessory Nerve Palsy and Winged Scapula: A Case Report.

Winged scapula is a rare musculoskeletal condition with numerous etiologies including spinal accessory nerve (SAN) palsy. Sport activities are rarely implicated with few scattered case reports. We report a case of an 18-year-old bodybuilder who suffered SAN palsy secondary to weightlifting exercises. Physical examination revealed winged scapula with painful mobility of the shoulder. A scapular magnetic resonance imaging scan and electromyography of the trapezius muscle were performed and confirmed the diagnosis of SAN palsy. Through this case, we review the literature of common and rare causes of SAN palsy and outline accepted treatment options.

Ultrasonic detection of vagus, accessory, and phrenic nerve atrophy in amyotrophic lateral sclerosis: Relation to impairment and mortality.

BACKGROUND AND PURPOSE: In amyotrophic lateral sclerosis (ALS), phrenic nerve (PN) atrophy has been found, whereas there is controversy regarding vagus nerve (VN) atrophy. Here, we aimed to find out whether PN atrophy is related to respiratory function and 12-month survival. Moreover, we investigated the relevance of VN and spinal accessory nerve (AN) atrophy in ALS. METHODS: This prospective observational monocentric study included 80 adult participants (40 ALS patients, 40 age- and sex-matched controls). The cross-sectional area (CSA) of bilateral cervical VN, AN, and PN was measured on high-resolution ultrasonography. Clinical assessments included the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R), the Non-Motor Symptoms Questionnaire, and handheld spirometry of forced vital capacity (FVC). One-year survival was documented. RESULTS: The CSA of each nerve, VN, AN, and PN, was smaller in ALS patients compared to controls. VN atrophy was unrelated to nonmotor symptom scores. PN CSA correlated with the respiratory subscore of the ALSFRS-R (Spearman test, r = 0.59, p < 0.001), the supine FVC (r = 0.71, p < 0.001), and the relative change of sitting-supine FVC (r = -0.64, p = 0.001). Respiratory impairment was predicted by bilateral mean PN CSA (p = 0.046, optimum cutoff value of ≤0.37 mm2 , sensitivity = 92%, specificity = 56%) and by the sum of PN and AN CSA (p = 0.036). The combination of ALSFRS-R score with PN and AN CSA measures predicted 1-year survival with similar accuracy as the combination of ALSFRS-R score and FVC. CONCLUSIONS: Ultrasonography detects degeneration of cranial nerve motor fibers. PN and AN calibers are tightly related to respiratory function and 1-year survival in ALS.

Anatomic Variability of the Accessory Nerve: Implications for Dissection of Level IIB.

OBJECTIVES: During neck dissection, level IIB lymphadenectomy necessitates manipulation of the spinal accessory nerve that might be avoided and might cause postoperative disability. Current literature does not describe the effect of variation in the spinal accessory nerve in the upper neck. We sought to measure the effect of the dimensions of level IIB on nodal yield in level IIB and on patient reported neck symptoms. METHODS: We measured the boundaries of level IIB of 150 patients undergoing neck dissection. Level II was dissected and separated into levels IIA and IIB intraoperatively. Patient-reported symptoms were assessed in 50 patients using the Neck Dissection Impairment Inventory. We computed descriptive statistics, and sought to identify correlation with the number and proportion of level IIB nodes and the number of metastatic nodes. Level IIB dimensions were analyzed as predictors of postoperative symptoms. RESULTS: We measured 184 sides, with 37.7% of level II nodes found in level IIB. Mean accessory nerve length across level II was 2.5 cm. Every additional 1 cm in accessory nerve length was associated with two more level IIB nodes. At all accessory nerve lengths, meaningful numbers of nodes were present in level IIB. Accessory nerve length and other factors did not correlate with NDII scores. CONCLUSIONS: Longer lengths of accessory nerve across level IIB correlated with greater nodal yield. However, data did not point to an accessory nerve length cutoff below which level IIB dissection could be avoided. In addition, the dimensions of level IIB did not correlate with postoperative neck symptoms. LEVEL OF EVIDENCE: 2 Laryngoscope, 134:154-159, 2024.

Spinal accessory nerve anatomy in the posterior cervical triangle: A systematic review with meta-analysis.

This study aimed to investigate the anatomy of the spinal accessory nerve (SAN) in the posterior cervical triangle, especially in relation to adjacent anatomical landmarks, along with a systematic review of the current literature with a meta-analysis of the data. Overall, 22 cadaveric and three prospective intraoperative studies, with a total of 1346 heminecks, were included in the analysis. The major landmarks relevant to the entry of the SAN at the posterior border of the SCM muscle (PBSCM) were found to be the mastoid apex, the great auricular point (GAP), the nerve point (NP), and the point where the PBSCM meets the upper border of the clavicle. The SAN was reported to enter the posterior cervical triangle above GAP in 100% of cases and above NP in most cases (97.5%). The mean length of the SAN along its course from the entry point to its exit point from the posterior triangle of the neck was 4.07 ± 1.13 cm. The SAN mainly gave off 1 or 2 branches (32.5% and 31%, respectively) and received either no branches or one branch in most cases (58% and 23%, respectively) from the cervical plexus during its course in the posterior cervical triangle. The major landmarks relevant to the entry of the SAN at the anterior border of the TPZ muscle (ABTPZ) were found to be the point where the ABTPZ meets the upper border of the clavicle and the midpoint of the clavicle, along with the mastoid apex, the acromion, and the transverse distance of the SAN exit point to the PBSCM. The results of the present meta-analysis will be helpful to surgeons operating in the posterior cervical triangle, aiding the avoidance of the iatrogenic injury of the SAN.

A Randomised Control Trial Comparing the Outcomes of Anterior with Posterior Approach for Transfer of Spinal Accessory Nerve to Suprascapular Nerve in Brachial Plexus Injuries.

Background: In brachial plexus surgery, a key focus is restoring shoulder abduction through spinal accessory nerve (SAN) to suprascapular nerve (SSN) transfer using either the anterior or posterior approach. However, no published randomised control trials have directly compared their outcomes to date. Therefore, our study aims to assess motor outcomes for both approaches. Methods: This study comprises two groups of patients. Group A: anterior approach (29 patients), Group B: Posterior approach (29 patients). Patients were allocated to both groups using selective randomisation with the sealed envelope technique. Functional outcome was assessed by grading the muscle power of shoulder abductors using the British Medical Research Council (MRC) scale. Results: Five patients who were operated on by posterior approach had ossified superior transverse suprascapular ligament. In these cases, the approach was changed from posterior to anterior to avoid injury to SSN. Due to this reason, the treatment analysis was done considering the distribution as: Group A: 34, Group B: 24. The mean duration of appearance of first clinical sign of shoulder abduction was 8.16 months in Group A, whereas in Group B, it was 6.85 months, which was significantly earlier (p < 0.05). At the 18-month follow-up, both intention-to-treat analysis and as-treated analysis were performed, and there was no statistical difference in the outcome of shoulder abduction between the approaches for SAN to SSN nerve transfer. Conclusions: Our study found no significant difference in the restoration of shoulder abduction power between both approaches; therefore, either approach can be used for patients presenting early for surgery. Since the appearance of first clinical sign of recovery is earlier in posterior approach, therefore, it can be preferred for cases presenting at a later stage. Also, the choice of approach is guided on a case to case basis depending on clavicular fractures and surgeon preference to the approach. Level of Evidence: Level II (Therapeutic).

"Winged" Eagle's syndrome: neurophysiological findings in a rare cause of spinal accessory nerve palsy. Illustrative cases.

BACKGROUND: Eagle's syndrome (ES) classically describes dysphagia, globus sensation, and otalgia from an elongated and calcified styloid process or stylohyoid ligament. Compression of the spinal accessory nerve (SAN) has not been reported as an associated feature of ES or related variants. OBSERVATIONS: The authors describe two cases of an atypical "winged" variant with SAN palsy resulting from compression by a posteriorly angulated or calcified styloid process. Both patients exhibited lateral scapular winging and atrophy of the trapezius and sternocleidomastoid muscles. Electrophysiological studies demonstrated motor unit preservation; therefore, surgical exploration, styloidectomy, and SAN decompression were performed through a transcervical approach. Postoperatively, both patients had improvements in pain and shoulder mobility, the return of muscle strength, and electrophysiological evidence of trapezius reinnervation. LESSONS: Compression of the SAN, which can be identified both clinically and on electrodiagnostic testing, is an atypical finding that can result from a posteriorly angulated or calcified styloid process. This winged variant of ES should be included in the differential for SAN palsy, and a multidisciplinary approach is recommended for assessment and management.

Topohistology of the cranial nerves IX-XII at the cranial base and upper parapharyngeal space: A histological study using human fetuses.

The topographical relationships among the lower cranial nerves, internal carotid artery (ICA), and internal jugular vein (IJV) in the upper parapharyngeal neurovascular bundle remain obscure. Thus, details of the anatomy were examined in human fetus histology. We observed the horizontal histological sections from 20 midterm (9-18 weeks) and 12 near-term (28-40 weeks) fetuses. At the external skull base, the glossopharyngeal nerve crosses the anterior aspect of the IJV to reach the medially located Hyrtl's fissure in the petrous temporal bone. The nerve crossed the anterior aspect of the ICA medially near or below the first cervical nerve root. Below the hypoglossal nerve canal, the accessory nerve crosses the anterior or posterior aspects of the IJV and moves laterally. During the half-spiral course, the hypoglossal nerve was tightly attached to the posterolateral-anterior aspects of the vagus nerve and surrounded by a common nerve sheath. The glossopharyngeal ganglia sometimes extended inferiorly to the level of the hypoglossal nerve canal but were absent along the inferior course. The inferior vagal ganglion rarely extends above the occipital condyle. The superior cervical sympathetic ganglion occasionally extends above the first cervical nerve root. The IJV (or ICA) descends to the lateral (or medial) margins of the parapharyngeal neurovascular bundle. The glossopharyngeal (or accessory) nerve crosses the ICA (or IJV) to exit the bundle at the base of the skull (or below the hypoglossal nerve canal). The glossopharyngeal and vagus inferior ganglia differ at each site.

The Clinical Outcomes of Spinal Accessory to Suprascapular Nerve Transfer Through a Posterior Approach.

BACKGROUND: Spinal accessory nerve (SAN) to suprascapular nerve (SSN) transfer can restore function to the rotator cuff following brachial plexus injuries. The traditional anterior approach using the lateral branch of the SAN causes denervation of the lateral trapezius limiting shoulder elevation. Suprascapular nerve pathology at the suprascapular notch may be missed resulting in poor reinnervation of the rotator cuff. The posterior approach uses the medial SAN and allows decompression and visualization of the SSN at the notch and nerve transfer coaptation closer to the target muscles with a shorter reinnervation distance. METHODS: This is a review of 28 patients from 2014 to February 2020 who underwent SAN to SSN nerve transfer via a posterior approach. Patients were evaluated for SSN pathology, external rotation power, and range of motion. Data were evaluated for high-energy trauma (HET) and low-energy trauma/nontraumatic etiology subsets. RESULTS: A total of 8 HET (40%) patients had pathology identified at the suprascapular notch during the posterior approach, including SSN scarring, ruptures, neuromata-in-continuity, and ossification of ligaments. British Medical Research Council grade greater than or equal to 4 shoulder external rotation was achieved in 75% patients with median range of motion 137.5°. CONCLUSIONS: Spinal accessory nerve to SSN transfer using a posterior approach allows visualization of pathology involving the SSN and coaptation of a medial SAN transfer close to the target muscles. Following HET, 8 cases (40%) had posterior pathology identified. Spinal accessory nerve to SSN transfer through a posterior approach shows improved external rotation power and range of motion.

Shoulder function after neck dissection with level IIb preservation: a prospective observational study.

BACKGROUND: Shoulder syndrome can be reduced by preserving the spinal accessory nerve (SAN). However, it is unclear whether performing level IIb preservation will decrease the risk of SAN injury and shoulder syndrome. AIMS/OBJECTIVES: We investigated whether neck dissection with level IIb preservation can reduce shoulder dysfunction and postoperative quality of life (QOL) in head and neck cancer patients. MATERIAL AND METHODS: This prospective observational study enrolled patients who underwent neck dissection from 2011 to 2014. Patients were divided into three groups (level IIb preservation group [group 1], IIb dissection group [group 2], and IIb and V dissection group [group 3]). Postoperative shoulder function and QOL were evaluated among the three groups. RESULTS: There were a total of 35 neck sides in three groups, with nine neck sides in group 1, 16 neck sides in group 2, and 10 neck sides in group 3. Although the results showed less shoulder dysfunction in group 1 at early postoperative period. The QOL in group 1 was preserved in the early postoperative period. CONCLUSIONS AND SIGNIFICANCE: Neck dissection with level IIb preservation may help reduce shoulder syndrome and maintain QOL in the early postoperative period.

Selective upper trunk posterior division fascicular nerve transfer for proximal spinal accessory neuropathy: illustrative case.

BACKGROUND: Spinal accessory nerve palsy can lead to severe shoulder pain and weakness, lateral scapular winging, and limitations in overhead activity. It most often occurs because of iatrogenic injury from procedures within the posterior triangle of the neck. OBSERVATIONS: The authors present the case of a 39-year-old male with symptoms of right shoulder weakness and neck pain after a total thyroidectomy and right neck dissection. With ultrasound findings of a neuroma-in-continuity but no clinical or electromyographic signs of reinnervation at 6 months, surgical intervention was indicated. Operative exploration confirmed a very proximal injury and nonconducting neuroma-in-continuity of the spinal accessory nerve. A selective distal nerve transfer from the posterior division of the upper trunk was performed. At the 2.5-year follow-up, the patient demonstrated excellent recovery of full active shoulder abduction and forward flexion, return to full-time employment, and mild residual scapular winging. LESSONS: Distal nerve transfers should be considered in cases of late presentation when primary repair is not possible or long interpositional grafts are required. Selective fascicular transfer from the posterior division of the upper trunk provides the advantages of a single incision, short reinnervation time, and synergistic donor function to facilitate motor reeducation.

Does Age Affect the Rate of Spinal Nerve Injury after Selective Neck Dissection? Age as a Prognostic Factor of Spinal Nerve Injury after Selective Neck Dissection.

OBJECTIVE: The objective of this study is to investigate whether age is a significant risk factor for spinal nerve injury following selective neck dissection (SND) in patients with head and neck cancer. METHODS: A retrospective cohort study was conducted on patients who had undergone SND for head and neck cancer at a tertiary hospital between 2020 and 2022. The primary outcome was the incidence of spinal nerve injury after SND. The secondary outcomes included the types and severity of spinal nerve injury and the impact of age on these outcomes. RESULTS: A total of 78 patients were included in the study and subdivided into two groups. Two shoulder-specific questionnaires (the Shoulder Pain and Disability Index (SPADI) and the Shoulder Disability Questionnaire (SDQ)) were administered to assess shoulder morbidity postoperatively. Twelve patients showed shoulder impairment following surgery. We divided the sample into two age-based groups; the older group showed a higher rate of SAN injury and the younger group showed a lower rate of improvement over time. CONCLUSION: This study suggests that age is a significant risk factor for spinal nerve injury following SND in patients with head and neck cancer. Older patients are more likely to experience spinal nerve injury after SND than younger patients. The findings of this study may help in the development of strategies to prevent spinal nerve injury in older patients undergoing SND for head and neck cancer.

Unilateral Fenestration of Internal Jugular Vein With a Radiological Clue: A Rare Case Report and Literature Review.

The intricacies of human anatomy continue to astound, as underscored by this unusual case of a 45-year-old female patient who presented to our esteemed otolaryngology department with T3N1MO squamous cell carcinoma of the lip. The preoperative diagnostic imaging of this patient divulged an enigmatic venous anomaly involving the internal jugular vein (IJV). Our team meticulously orchestrated a wide local excision of the primary tumor and modified radical neck dissection with Abbe Estlander flap reconstruction. Identification of the anomaly during the preoperative phase helped in meticulous planning and preparation. Thus, the surgical team was well-prepared for neck dissection and successfully navigated the rare IJV fenestration without incurring nerve or vascular injuries. This remarkable case accentuates the importance of maintaining a profound understanding of potential anatomical aberrations while performing intricate surgical procedures such as neck dissections. Heightened awareness can circumvent inadvertent damage to critical structures, ultimately safeguarding patient well-being. In this captivating report, we explain the preoperative suspicion, intraoperative identification, and subsequent outcome of a rare fenestration of the IJV encountered during a challenging neck dissection.

Shoulder Dysfunction Post Spinal Accessory Nerve Preserving Neck Dissections: Our Experience.

Apart from complete surgical clearance of the malignancy, reducing morbidity and improving quality of life of the patient is also considered. One of the morbidities linked with neck dissections is shoulder dysfunction. The aim of our study is to analyse the functional outcomes in patients operated for various neck dissections with preservation of the Spinal accessory nerve. A single centre prospective observational study was conducted in a total of 45 patients with oral cancers. These patients underwent Wide local excision of the primary tumour along with neck dissection. Tests for assessing spinal accessory nerve function was elicited in all these patients preoperatively and postoperatively. Patients were examined for shoulder pain and shoulder disability using Arm abduction test. All 45 patients underwent spinal accessory nerve preserving neck dissection. On post operative day 10, 89% of patients showed arm abduction test score of 1 and 47% of patients had a pain score of 6 whereas 13% had a pain score of 8. After 6 months of rehabilitation and regular follow up, 62% of the patients had improved arm abduction test score of 4 and above and all 45 patients had pain score improved to score of 4 and less. Variable amount of shoulder dysfunction is seen even in spinal accessory nerve preserving neck dissections. But active rehabilitation and regular follow up of these patients reduces the morbidity associated with shoulder syndrome.

Needle electromyography abnormalities in the upper trapezius muscle in neuromuscular disorders.

BACKGROUND: : Needle electromyography (EMG) abnormalities in the trapezius muscle (TM) can be seen in neuromuscular disorders. The aim was to determine the characteristics of needle EMG abnormalities observed in the TM in neuromuscular disorders. METHODS: The data of patients who applied to the Clinical Neurophysiology Laboratory of University of Health Sciences Adana City Training and Research Hospital between December 2018 and October 2021 were reviewed. Polio survivors, amyotrophic lateral sclerosis (ALS) patients, patients with sensorimotor polyneuropathy, patients with spinal cord lesions involving C2/C3/C4 segments, patients with spinal accessory nerve (SAN) lesions, neuralgic amyotrophy (NA) patients, and patients with myopathy were included. Needle EMG findings of the upper TM of the patients were analyzed. Positive sharp waves, fibrillation potentials, fasciculation potentials, myotonic discharges, and motor unit action potential (MUAP) changes were considered needle EMG abnormalities. RESULTS: Eighty-one polio survivors, 23 ALS patients, 39 patients with sensorimotor polyneuropathy, 10 patients with cervical spinal lesions, eight NA patients, seven patients with SAN lesions, and three patients with myopathy were included in the study. Fifteen (65.2%) ALS patients, 18 (22.2%) polio survivors, three (30%) patients with cervical spinal lesions, two (5.1%) patients with sensorimotor neuropathy, one (12.5%) NA patient, seven (100%) patients with SAN lesions, and two (66.7%) patients with myopathies had at least one needle EMG abnormality in the TM. Fasciculation potentials in the TM were seen in 10 (43.5%) ALS patients. In four patients with SAN lesions and one polio survivor, MUAP could not be obtained from the TM. DISCUSSION: There may be more frequent needle EMG abnormalities, particularly in ALS patients and patients with SAN lesions. Since the number of patients with myopathy included in this study was low, it is difficult to comment on the needle EMG features of the TM for these patients. In addition, this study indicated that fasciculation potentials in the TM are typical in ALS patients and that MUAP may not be obtained from the TM in patients with SAN lesions.

Effect of shorter nerve graft and selective motor branch of recipient nerve on nerve transfer surgery for elbow flexion in patients with brachial plexus injury.

OBJECTIVE: The spinal accessory nerve (SAN) is commonly used as a donor nerve for reinnervation of elbow flexors in brachial plexus injury (BPI) reconstruction. However, no study has compared the postoperative outcomes between SAN-to-musculocutaneous nerve (MCN) transfer and SAN-to-nerve to biceps (NTB) transfer. Thus, this study aimed to compare the postoperative time to recovery of elbow flexors between the two groups. METHODS: A total of 748 patients who underwent surgical treatment for BPI between 1999 and 2017 were retrospectively reviewed. Among them, 233 patients were treated with nerve transfer for elbow flexion. Two techniques were used to harvest the recipient nerve: the standard dissection technique and the proximal dissection technique. The postoperative motor power of elbow flexion was assessed every month for 24 months using the Medical Research Council (MRC) grading system. Survival and Cox regression analyses were used to compare the time to recovery (MRC grade ≥ 3) between the two groups. RESULTS: Of the 233 patients who underwent nerve transfer surgery, there were 162 patients in the MCN group and 71 patients in the NTB group. At 24 months after surgery, the MCN group had a success rate of 74.1%, and the NTB group had a success rate of 81.7% (p = 0.208). When compared with the MCN group, the NTB group had a significantly shorter median time to recovery (19 months vs 21 months, p = 0.013). Only 11.1% of patients in the MCN group regained MRC grade 4 or 5 motor power 24 months after nerve transfer surgery compared with 39.4% patients in the NTB group (p < 0.001). Cox regression analysis showed that the SAN-to-NTB transfer in combination with the proximal dissection technique was the only significant factor affecting time to recovery (HR 2.33, 95% CI 1.46-3.72; p < 0.001). CONCLUSIONS: SAN-to-NTB transfer in combination with the proximal dissection technique is the preferred nerve transfer option for restoration of elbow flexion in traumatic pan-plexus palsy.

Accessory nerve schwannoma extending into the fourth ventricle: case report and review of literature.

Accessory nerve schwannoma is a rare entity in patients presenting with cranial nerve (CN) deficits. Most of these tumours arise from the cisternal segment of the eleventh CN and extend caudally. Herein, we report the third case of an accessory schwannoma extending cranially into the fourth ventricle. A 61-year-old female presented with a history of variable headaches. Cerebral magnetic resonance imaging (cMRI) revealed a large inhomogeneous contrast-enhancing lesion at the craniocervical junction extending through the foramen of Magendi and concomitant hydrocephalus due to obstruction of the foramina of Luschkae. Microsurgical tumour resection was performed in the half-sitting position. Intraoperatively, the tumour arose from a vestigial fascicle of the spinal accessory nerve. At three month follow-up, neither radiological tumour recurrence nor neurological deficits were observed.

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.