The spinal accessory nerve and its entry point into the posterior triangle of the neck.

BACKGROUND: The course of the spinal accessory nerve in the neck is long and superficial rendering it at high risk of injury during procedures performed in the posterior triangle. The majority of spinal accessory nerve injuries are iatrogenic in nature. This is associated with significant morbidity including reduction in shoulder movements, drooping of the shoulder, winging of the scapula and neuropathic pain. Knowledge of the nerve anatomy reduces the risk of intra-operative nerve injury. Traditional teaching describes the point of entry into the posterior triangle as the intersection between the upper and middle third of the posterior border of sternocleidomastoid. The aim of this study was to determine whether this is in fact the case and if so, whether this landmark can reliably be used to identify the spinal accessory nerve in order to improve patient outcomes. MATERIALS AND METHODS: The spinal accessory nerve was identified unilaterally in 26 cadavers. The total length of sternocleidomastoid was measured as well as the length along the posterior border from the inferior aspect of the mastoid process to the point at which the accessory nerve enters the posterior triangle of the neck. These measurements were used to calculate the ratio of the entry point of the nerve into the posterior triangle along the length of the posterior border of sternocleidomastoid from its superior insertion point. The mean ratio was 0.35 with 95% confidence intervals of 0.33 to 0.36. RESULTS AND CONCLUSIONS: Our findings confirm the traditional description of the entry point of the spinal accessory nerve into the posterior triangle of the neck. We describe a so-called 'safe zone' inferior to the midpoint of the posterior border of sternocleidomastoid within which the spinal accessory nerve is unlikely to be found, thereby reducing the risk of iatrogenic injury.

Accessory Nerve Disruption Following Core-Needle Biopsy: A Review of Iatrogenic Accessory Nerve Injuries and an Illustrative Case.

Iatrogenic spinal accessory neve (SAN) injury is a rare complication. It most commonly occurs after open lymph node biopsies. Needle biopsy is thought to present lower risk to the SAN. However, we describe a case of a 66-year-old man who underwent core needle biopsy for lymphadenopathy and subsequently experienced ipsilateral shoulder weakness and pain. Physical examination revealed shoulder depression, lateral scapular winging, and decreased range of motion. Subsequent studies and magnetic resonance imaging demonstrated complete paralysis and denervation of SAN muscles. The nonfunctional SAN was repaired by sural nerve grafting 3 months after the injury. The patient demonstrated improved shoulder strength, range of motion, and decreased pain at 6-month follow-up. SAN injuries can be challenging to diagnose and require prompt surgical intervention. This case represents an unusual case of complete SAN disruption and palsy after core needle biopsy treated with sural nerve grafting. We review the literature on iatrogenic SAN injuries, diagnostic strategies, options for SAN surgical repair, and outcomes. SAN injuries can be challenging to diagnose but are amenable to prompt surgical options based on the mechanism and type of SAN injury.

Preoperative ultrasound accurately characterizes surgically confirmed extracranial spinal accessory nerve injuries.

OBJECTIVE: To determine the accuracy of preoperative ultrasound and MRI in surgically confirmed spinal accessory nerve injuries and present the benefits of a multimodality image review. MATERIALS AND METHODS: A retrospective review of 38 consecutive patients referred to a peripheral nerve surgical practice at an academic teaching hospital with surgically confirmed spinal accessory nerve injuries. All cases were reviewed for patient demographics, date and cause of injury, preoperative EMG, and surgical diagnosis and management. Additionally, prospective interpretation of preoperative ultrasound and MRI reports were reviewed for concordance or discordance with the surgical diagnosis. RESULTS: Iatrogenic injury was present in 37 (97%) cases and most commonly a result of an excisional lymph node biopsy (68%). Surgically confirmed spinal accessory nerve injury diagnoses consisted of 25 (66%) stump neuromas and 13 (34%) incomplete nerve injuries. Nine months was the average time from injury to surgery. Twenty-nine patients underwent preoperative ultrasound and/or MRI evaluation: 12 ultrasound only, 10 MRI only, and seven with both ultrasound and MRI. Eighteen (95%) preoperative ultrasound reports compared to four (24%) preoperative MRI reports were concordant with the surgical diagnosis. In the seven cases with both preoperative ultrasound and MRI, six had discordant ultrasound and MRI imaging diagnoses for which the ultrasound was concordant with the surgical diagnoses in all cases. CONCLUSION: Preoperative ultrasound more accurately characterizes spinal accessory nerve injuries compared to MRI and should serve as the modality of choice when a spinal accessory nerve injury is suspected.

Tendon transfer for trapezius palsy.

The trapezius muscle produces upward scapular rotation that in turn allows complete lateral elevation (abduction) by maintaining the acromiohumeral distance and the deltoideus resting length. Loss of trapezius function leads to shoulder drooping, loss of scapular external rotation with secondary loss of abduction. When conservative treatment has failed and in cases where nerve surgery is not indicated, the most common procedure for treating this condition is the Eden-Lange (EL) procedure. This procedure entails transferring the levator scapulae (LS) to the lateral part of the scapular spine, and the rhomboid major (RM) and minor (Rm) to the infraspinatus fossa to restore the lost trapezius function. Recently, Elhassan et al. proposed a modification of the original EL procedure to recreate the line of pull of the different parts of the trapezius muscle. The modified transfer may yield successful outcomes in patients with trapezius paralysis who failed to improve after well-conducted conservative treatment. Longer follow-up is needed to confirm the stability of the good outcomes of this reconstruction.

Scapular Winging Secondary to Iatrogenic Spinal Accessory Nerve Lesions.

Motor innervation of trapezius and sternocleidomastoid (SCM) muscles is provided solely by the spinal accessory nerve (SAN). SAN palsy most often occurs as a result of iatrogenic injury to the nerve. A patient, who had undergone neck dissection for thyroid cancer, presented with pain and reduced range of motion of the shoulders. Electroneuromyography revealed denervation of the trapezii and SCM muscles secondary to SAN injury. The patient was treated with a course of physical therapy (PT). This case reminds us that a SAN lesion should be considered in the differential diagnosis of a patient presenting with shoulder pain following surgery of the neck. Even though unilateral SAN injury can eventually lead to atrophy of the trapezius, muscle asymmetry may not be obvious, especially in bilateral iatrogenic SAN injuries. In our experience, these patients benefit from PT. However, evidence to support the use of PT in the treatment of shoulder dysfunction secondary to SAN injury is insufficient; the optimum type and timing of PT requires further investigation. Development of best-practice guidelines in terms of management is necessary. Key Words: Spinal accessory nerve, Electroneuromyography, Scapular winging.

Detrusor underactivity causes neurogenic voiding dysfunction in a rat bilateral accessory nerve-injury model.

We aimed to investigate detrusor function in a previously developed rat neurogenic voiding dysfunction model that we have developed previously. We performed sham or bilateral accessory nerve injury (BACNI) surgeries on ten-week-old male Wistar/ST rats. One week after surgery, we evaluated detrusor contractility in the bladder using isometric tension and mRNA expression assays. Cholinergic contraction was attenuated in the injury model, whereas carbachol-evoked contraction was enhanced, and mRNA expression of the cholinergic receptor increased. These findings suggest that there was a reduction in neurotransmitter release causing detrusor underactivity.

Complications after Functional Neck Dissection in Head and Neck Cancer Patients: An Observational, Retrospective, Single-Centre Study.

INTRODUCTION: Functional neck dissection (FND) represents a surgical procedure usually associated with less morbidity. METHODS: An observational, retrospective, analysis of patients diagnosed with any type of head and neck malignancy was designed to summarize and report the incidence of postoperative complications in patients undergoing FND including just those levels described for selective neck dissections in a tertiary university hospital between June 2016 and June 2019. RESULTS: 131 patients met the inclusion criteria. The total number of sides studied was 200. 40.5% of the patients suffer a complication in the postoperative period, being the spinal accessory nerve (SAN) injury the most common complication (10%). We did not find any statistical -correlation between the previous organ-preservation treatments and surgical complications (p = 0.207). An advanced T stage (p = 0.009) and the need of bilateral FND (p = 0.034) were significantly correlated with a higher risk of surgical complications. CONCLUSION: FND represents a useful technique. In this study, 40.5% of the patients suffer a complication in the postoperative period, being the SAN injury the most common complication. However, these data contribute to increasing our knowledge about surgical complications related to FND.

Spinal Accessory and Suprascapular Nerve Injury After Human Bite.

ABSTRACT: This is a unique clinical case of spinal accessory and suprascapular nerve injury related to a human bite not yet described elsewhere. The case emphasizes the importance of considering local trauma of the posterior triangle of the neck in case of shoulder weakness with electrophysiologic evidence of combined spinal accessory and suprascapular nerve injury.

Usefulness of ultrasonography for diagnosing iatrogenic spinal accessory nerve palsy after lymph node needle biopsy: a case report.

BACKGROUND: Spinal accessory nerve (SAN) palsy is rare in clinical settings. Iatrogenicity is the most common cause, with cervical lymph node biopsy accounting for > 50% of cases. However, SAN palsy after lymph node needle biopsy is extremely rare, and the injury site is difficult to identify because of the tiny needle mark. CASE PRESENTATION: A 26-year-old woman was referred to our hospital with left neck pain and difficulty abducting and shrugging her left shoulder after left cervical lymph node needle biopsy. Five weeks earlier, a needle biopsy had been performed at the surgery clinic because of suspected histiocytic necrotizing lymphadenitis. No trace of the needle biopsy site was found on the neck, but ultrasonography (US) showed SAN swelling within the posterior cervical triangle. At 3 months after the injury, her activities of daily living had not improved. Therefore, we decided to perform a surgical intervention after receiving informed consent. We performed neurolysis because the SAN was swollen in the area consistent with the US findings, and nerve continuity was preserved. Shoulder shrugging movement improved at 1 week postoperatively, and the trapezius muscle manual muscle testing score recovered to 5 at 1 year postoperatively. The swelling diameter on US gradually decreased from 1.8 mm preoperatively to 0.9 mm at 6 months. CONCLUSION: We experienced a rare case in which US was useful for iatrogenic SAN palsy. Our results suggest that preoperative US is useful for localization of SAN palsy and that postoperative US for morphological evaluation of the SAN can help assess recovery.

Accessory spinal nerve damage during a cervical lymph node biopsy: case report.

The lesion of the accessory spinal nerve is often of iatrogenic origin. We report the case of an injury after a right jugulocarotid lymph node biopsy. A 30-year-old patient was referred for the treatment of right cervical lymphadenopathy suspected of tuberculosis. After the intervention and confirmation of tuberculosis diagnosis, the patient presented a functional impotence of the right shoulder and swarming of the right hand. The clinical examination found an active limitation of the shoulder, and a wasting of the upper bundle of the right trapezius muscle and the sternocleidomastoid. The EMG showed axonotmesis of the accessory spinal nerve and the MRI an amyotrophy of the trapezius with denervation edema. A simple rehabilitation has been scheduled. Damage of the accessory spinal nerve most often occurs after local surgery. EMG is essential for diagnosis. Rehabilitation is the first therapeutic option. Surgery can be considered if it fails. The surgeons must consider the protection of the accessory spinal nerve in case of cervical lymph node surgery.

The prevalence of nerve injuries following neck dissections - a systematic review and meta-analysis.

INTRODUCTION: Symptoms of the shoulder syndrome (SS) and spinal accessory nerve (SAN) impairments are well-known complications to any neck dissections (NDs). Even so, their prevalence is reported with large variations in the literature. Furthermore, marginal mandibular nerve (MMN) injuries are claimed to be underreported. The purpose of this study was to investigate the prevalence of SS, SAN and MMN injuries after different types of ND. METHODS: This systematic review and meta-analysis included studies reporting SAN and MMN injuries following the three main types of ND. Pooled estimates of the prevalence were made by the main types of ND with 95% confidence intervals (95% CI). RESULTS: Nineteen studies reported a total of 457 SAN injuries. The estimated prevalence of SS or SAN injuries following radical neck dissection, modified radical neck dissection and selective neck dissection was 94.8% (95% CI: 88.5-98.9%), 33.0% (95% CI: 19.4-48.3%) and 27.9% (95% CI: 7.1-54.5%), respectively. Five studies reported a total of 64 MMN injuries. The estimated prevalence following modified radical neck dissection and selective neck dissection was 13.1% (95% CI: 0-37.6%) and 12.7% (95% CI: 4.3-24.1%), respectively. CONCLUSIONS: This meta-analysis estimated a high prevalence of SS, SAN and MMN injuries following the three main types of ND. If oncological considerations allow it, the less morbid ND should be considered. MMN injuries have only been reported in a limited number of small studies. The results may be used to compare future research and as guidance for quality evaluation within departments.

Dual spinal accessory nerve: caution during neck dissection.

Preserving the spinal accessory nerve (SAN) is an important step in the modern-day neck dissection to avoid postoperative functional morbidity in patients. This goal can become technically difficult, especially, when rare anatomical variations are encountered. We present a case of dual SAN in a patient undergoing selective neck dissection for oral squamous cell carcinoma. Both SANs were preserved and patient had no shoulder dysfunction postoperatively. We take this opportunity to emphasise that meticulous dissection is the only proven way to preserve the nerve. And that surgeons should be aware of this anatomical variation. SAN should be subjected to minimal traction during neck dissection to avoid tension neuropraxia and long-term shoulder dysfunction.

Spinal Cord Stimulation for Neuropathic Pain Treatment in Brachial Plexus Avulsions: A Literature Review and Report of Two Cases.

BACKGROUND: At least 50% of individuals who suffer a brachial plexus avulsion (BPA) will develop chronic pain, frequently more debilitating than their functional limitations. Similar to other neuropathic pain states, BPA pain is often refractory to pharmacological agents. Despite spinal cord stimulation (SCS) first being used for BPA in 1974, there have been no published literature reviews examining the current evidence of SCS for the treatment of neuropathic pain following BPA. In addition to a clinical review of the literature for this indication, we also share our experience with high-frequency SCS (HF-SCS) for BPA-related pain. METHODS: MEDLINE and EMBASE databases were searched. All published articles including at least one BPA individual treated with SCS for pain treatment were included. RESULTS: The initial search identified 288 articles, of which 13 met inclusion criteria for a total of 41 patients. These patients were primarily male and underwent SCS with reported improved pain scores. CASE REPORTS: HF-SCS leads were percutaneously placed in two male patients who suffered BPA from traumatic injuries. At follow-ups of 13 and eight months, respectively, both patients continued to report an improvement in their pain. CONCLUSIONS: Despite published reports showing benefit for pain control in patients with BPA, the overall low quality, retrospective evidence included in this review highlights the need for a rigorous prospective study to further address this indication.

Viral Vector-Mediated Gene Transfer of Glutamic Acid Decarboxylase for Chronic Pain Treatment: A Literature Review.

Chronic pain is long-lasting nociceptive state, impairing the patient's quality of life. Existing analgesics are generally not effective in the treatment of chronic pain, some of which such as opioids have the risk of tolerance/dependence and overdose death with higher daily opioid doses for increasing analgesic effect. Opioid use disorders have already reached an epidemic level in the United States; therefore, nonopioid analgesic approach and/or use of nonpharmacologic interventions will be employed with increasing frequency. Viral vector-mediated gene therapy is promising in clinical trials in the nervous system diseases. Glutamic acid decarboxylase (GAD) enzyme, a key enzyme in biosynthesis of γ-aminobutyric acid (GABA), plays an important role in analgesic mechanism. In the literature review, we used PubMed and bioRxiv to search the studies, and the eligible criteria include (1) article written in English, (2) use of viral vectors expressing GAD67 or GAD65, and (3) preclinical pain models. We identified 13 eligible original research articles, in which the pain models include nerve injury, HIV-related pain, painful diabetic neuropathy, and formalin test. GAD expressed by the viral vectors from all the reports produced antinociceptive effects. Restoring GABA systems is a promising therapeutic strategy for chronic pain, which provides evidence for the clinical trial of gene therapy for pain in the near future.

2b or not 2b? Shoulder function after level 2b neck dissection: A double-blind randomized controlled clinical trial.

BACKGROUND: Selective neck dissection (SND) is a mainstay of head and neck cancer treatment. A common sequela is shoulder syndrome from spinal accessory nerve (SAN) trauma. Extensive dissection in neck levels 2 and 5 leads to SAN dysfunction. However, it is not known whether limited level 2 dissection reduces SAN injury. The purpose of this double-blind randomized controlled trial was to determine whether omitting level 2b dissection would improve shoulder-related quality of life and function. METHODS: Patients with head and neck cancers undergoing surgery were randomized 1:1 to SND without level 2b dissection (group 1) or with it (group 2) on their dominant-hand side. Patients, caregivers, and assessors were blinded. The primary outcome was the change in the Neck Dissection Impairment Index (NDII) score after 6 months. An a priori calculation of the minimally important clinical difference in the NDII score was determined to establish a sample size of 15 patients per group (power = 0.8). Secondary outcomes included shoulder strength and range of motion (ROM) and SAN nerve conduction. The trial was registered at ClinicalTrials.gov (NCT00765791). RESULTS: Forty patients were enrolled, and 30 were included (15 per group). Six months after the surgery, group 2 demonstrated a significant median decrease in the NDII from the baseline (30 points) and in comparison with group 1, whose NDII dropped 17.5 points (P = .02). Shoulder ROM and SAN conduction demonstrated significant declines in group 2 (P ≤ .05). No adverse events occurred. CONCLUSIONS: Level 2b should be omitted in SND when this is oncologically safe and feasible. This allows for an optimal balance between function and cancer cure.

The necessity of IIb dissection in T1-T2N0M0 oral squamous cell carcinoma: protocol for a randomized controlled trial.

BACKGROUND: There is a growing debate on the relationship between health-related quality of life (HRQoL) and patient survival which has been going on for the last few decades. The greatest wish of clinicians is to extend the latter while improving the former. Following neck dissection of early-stage oral carcinoma, "shoulder syndrome" appears due to traction of the accessory nerve during removal of level IIb, which greatly affects patient quality of life. Since occult metastasis in level IIb of early-stage oral carcinoma is extremely low, some surgeons suggest that level IIb can be exempt from dissection to improve the HRQoL. However, other surgeons take the opposite view, and thus there is no consensus on the necessity of IIb dissection in T1-2N0M0 oral squamous cell carcinoma (OSCC). METHODS: We designed a parallel-group, randomized, non-inferiority trial that is supported by Shanghai Ninth People's Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China. We will enroll 522 patients with early oral carcinoma who match the inclusion criteria, and compare differences in 3-year overall survival, progression-free survival (PFS) and HRQoL under different interventions (retention or dissection of level IIb). The primary endpoints will be tested by means of two-sided log-rank tests. Analysis of overall and progression-free survival will be performed in subgroups that were defined according to stratification factors with the use of univariate Cox analysis. In addition, we will use post-hoc subgroup analyses on the basis of histological factors that were known to have effects on survival, such as death of invasion of the primary tumor. To evaluate HRQoL, we will choose the Constant-Murley scale to measure shoulder function. DISCUSSION: Currently, there are no randomized controlled trials with large sample sizes on the necessity of IIB dissection in T1-T2N0M0 OSCC. We designed this noninferiority RCT that combines survival rate and HRQoL to assess the feasibility of IIb neck dissection. The result of this trial may guide clinical practice and change the criteria of how early-stage oral cancer is managed. The balance between survival and HRQoL in this trial is based on early-stage breast cancer treatment and may provide new ideas for other malignancies. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1800019128 . Registered on 26 October 2018.

Unsafe workout: a weak and painful shoulder in a professional volleyball player.

A 29-year-old professional volleyball player started complaining of a dull ache in the right lateral base of the neck. This pain arose during a preseasonal athletic training intense session. After 3 days, he presented deficiency of right scapula adduction, limitation of scapula elevation, right shoulder weakness and local mild pain. He had asymmetrical neckline with drooping of the affected shoulder, lateral displacement and minimal winging of the right scapula. After 1 week, hypothrophy of superior trapezius appeared. An electromyography of right upper limb showed a denervation in the upper, middle and lower components of the right trapezius muscle, due to axonotmesis of spinal accessory nerve (SAN). A subsequent MRI was consistent with muscular suffering caused by early denervation. This case shows idiopathic SAN palsy, likely secondary to an inappropriate use of a weight-lifting machine, where the athlete recovered after an adequate rest and rehabilitation period.

Ultrasonic identification of internal jugular vein fenestration.

OBJECTIVE: Anatomic variations have curicial importance during neck surgery. We present a fenestrated internal jugular vein variation and the accessory nerve passing through it. Also, we discuss preoperative diagnosis of this variation using ultrasonography. METHOD: The possible recognition of this variation by ultrasonography is introduced. RESULTS: The accessory nerve in an internal jugular vein fenestration can be seen using ultrasonography. CONCLUSION: Preoperative identification of this rare variation may secure surgeon from potential complications.