Spinal Accessory Nerve Injury Research Articles

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.

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.

Assessment of level IIB lymph nodes in oral cancer - Should we spare or care?

Objectives The extent of neck dissection over the years has evolved from a radical neck dissection to a super-selective neck dissection with an attempt to achieve a balance between oncological safety and acceptable morbidity. There is an ongoing debate concerning dissection of level IIB in both node negative and positive patients, primarily due to the low incidence of metastasis in this region and possible spinal accessory nerve injury. In this study, we intended to find the rate of metastasis to level IIB nodes in patients who were treated with neck dissection for oral cancers. Material and Methods Patients with squamous cell carcinoma of the oral cavity who underwent neck dissection were analyzed. Patients with clinically node negative (cN0) disease underwent selective neck dissection (SND), whereas patients with clinically node positive (cN+) disease underwent modified radical neck dissection (MRND). Results Out of the total 34 patients, 12 patients underwent MRND and 22 patients underwent SND. In the MRND group, three patients (25%) had positive level IIB nodes. The median number of IIB nodes removed was two and the median number of positive IIB nodes was one. In the SND group, the median number of IIB nodes removed was three and none of the patients had positive level IIB node. Conclusion In oral cancer with cN+, routine dissection of level IIB nodes has both therapeutic and prognostic values. Whereas, in patients with cN0, routine dissection of level IIB nodes can be omitted. Further large volume studies are needed on cN0 disease.

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

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. 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. 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.

Complications of neck dissection and their management: Retrospective study

Neck dissection (ND) is a surgical procedure performed in treating head and neck cancer patients with or without cervical nodal neck metastasis. The aim of neck dissection is to achieve loco-regional control thus optimizing the cancer cure rate. Various complications may potentially occur following this surgery. Previous studies done have documented the complication rate following neck dissection surgery to range between 5% to 15%. Most of the complications are inevitable and various efforts have been made to try and reduce complications by modifying the aggressive surgical procedure. The objective of this study is to report the various complications, its rate in various neck dissection procedures, their management and to seek improved patient care and outcome. : A systematic review of 73 patients who underwent neck dissection for various head and neck cancers from August 2017 to July 2020. These patients were studied for post-operative complications and their management.Out of 73 patients, Vascular injury observed in the current study was internal jugular vein (IJV) and was seen in 22.7%) cases and was repaired intraoperatively. Throracic duct injury was identified in 3(4.1%) and it was identified and ligated intraoperatively. Immediate post-operative complication being hemorrhage was seen among 2 cases, both the cases were re-opened. Marginal mandibular nerve and spinal accessory nerve injury was observed in 3 cases and they both came under the delayed type of complications.: A careful preoperative assessment, meticulous surgical technique, high quality postoperative care and appropriate rehabilitation are the cornerstone of preventing and managing complications.

Iatrogenic Spinal Accessory Nerve Injury and Association with Great Auricular Nerve: A Report of Three Cases

Iatrogenic Spinal Accessory Nerve Injury and Association with Great Auricular Nerve: A Report of Three Cases

Modified Eden-Lange Triple-Tendon Transfer for Chronic Trapezius Palsy

Background: Trapezius palsy can occur due to traumatic or idiopathic spinal accessory nerve injury. As a result of trapezius palsy, shoulder girdle imbalance can develop and present as lateral scapular winging and diminished shoulder range of motion and function. The modified Eden-Lange triple-tendon transfer procedure is a notable salvage operation which can treat chronic trapezius palsy after failure of conservative and nonsalvage interventions. Indications: A 42-year-old right-hand dominant woman who underwent a cervical lymph node biopsy 3 years before presents with chronic left shoulder weakness, severe shoulder pain, and scapular winging. On presentation, she has failed conservative treatments and operative interventions including attempted spinal accessory nerve exploration and repair with ansa cervicalis autograft. Technique Description: A modified Eden-Lange triple-tendon transfer, using the Elhassan modification, was performed to treat the patient’s chronic trapezius palsy. The levator scapulae, rhomboid minor, and rhomboid major were sequentially transferred to the lateral scapular spine, central scapular spine, and medial scapular spine, respectively. Results: At interval follow-up, the patient was recovering well from her operation and with progressively improving range of motion and strength. Discussion/Conclusion: The modified Eden-Lange triple-tendon transfer technique is a salvage procedure for treating chronic trapezius palsy by anatomically reconstructing the force vectors of the native trapezius muscle. Effective restoration of proper scapular and shoulder kinematics via the triple-tendon transfer technique can result in improved pain and shoulder girdle function. The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Incidence and Characteristics of Cranial Nerve Injuries: A Nationwide Observational Study in Japan.

Background: Large-scale data on cranial nerve injuries are scarce. Methods: This study enrolled 361,706 patients registered in the Japanese Trauma Data Bank from 2004 to 2018. We selected patients with cranial nerve injury using the corresponding Abbreviated Injury Scale codes and examined the incidence and characteristics. Results: In total, 347,101 patients were eligible for inclusion in our analysis. By mechanism of trauma, all cranial nerve injuries occurred in <1% of registered cases. The highest incidence was 0.2190% (55/25,117) for facial nerve injury in bicycle crash. By cause of trauma, all cranial nerve injuries occurred in <1% of registered cases. The highest incidence was 0.1943% (37/19,044) for facial nerve injury in occupational injury. No patients with spinal accessory nerve injury were observed. The most common cranial nerve injury was to the facial nerve (n = 278). Most cranial nerve injury patients are in the 30s to 50s age range, and there was a male predominance. Multiple cranial nerve injuries were observed in 81 patients. Many cranial nerve injury cases are complicated by skull base fractures. Conclusions: We revealed the incidence and characteristics of cranial nerve injury. Our findings may help physicians detect these injuries at an early stage in patients at risk.

Spinal accessory to suprascapular nerve transfer in brachial plexus injury: outcomes of anterior vs. posterior approach to the suprascapular nerve at associated ipsilateral spinal accessory nerve injury

Objective: The spinal accessory nerve (Acc) is susceptible to trauma in at least 6% of cases of brachial plexus injury (BPI). The impaired Acc function disables its utilization for transfer to the suprascapular nerve (SS). The selection of approach to SS is highly dependant on the anatomy of BPI. The purpose of this study was to determine the incidence of the anterior-posterior approach of Acc to SS transfer in BPI and associated functional outcomes. Methods. Twenty nine patients with BP/Acc associated injury were included. Ten patients underwent the transfer of Acc to SS by the anterior approach (AA), 19 patients – by the posterior approach (PA). Nine nerve transfers through AA and one nerve transfer through PA required the interposition of an autologous nerve graft. The functioning of the supra-/infraspinatus muscle was evaluated at 9 and 15mos. on the basis of the MRC and the external rotation (ER) range. ER more than +400 beyond the sagittal plane was regarded as effective recovery of function. Results. Impaired function (M3 or lower on MRC) of the lower trapezius muscle was associated with preserved anatomy of the SS in the supraclavicular region in 9 out of 10 cases. Eighteen patients (62%) recovered to M3 and higher (shoulder stability), 11of these (38%) showed recovery to M4-M5. Five of all patients recovered to M4-M5 and were able to produce ER within the effective ROM (+400-600 of ER). After the AA to the SS, shoulder stability was restored in 60% of cases (M4-M5 in 30%). After the PA to the SS, shoulder stability was restored in 74% of cases (M4-M5 in 42%). Only non-complete BPI showed effective recovery of power and function in terms of less than 6 mos. after injury. PA to SS with no graft provided shoulder stability in 72% of cases, AA to the SS and the graft interposition ensured shoulder stability in 50% of cases. Conclusions. The incidence of AA to the SS was 35%, PA – 65%; preserved anatomy of the SS in supraclavicular region was associated with an increased risk of trapezius muscle dysfunction; the PA to SS and consecutive direct end-to-end transfer of Acc showed better results compared to other combinations of nerve transfers in providing shoulder stability.

117 Management of Spinal Accessory Nerve Palsy

Abstract Aim To discuss our strategies employed in our peripheral nerve injury unit for spinal accessory nerve (SAN) injury and a potential algorithm for future use. Method A retrospective analysis was undertaken on 9 patients with SAN injury undergoing surgical intervention. Neurophysiological results were obtained. MRC grades were compared at presentation and post-operatively. DASH (Disability of the arm, shoulder, and hand) scores were also collected post-operatively. Results 7 patients presented to us following an iatrogenic injury to the SAN. 6 patients underwent neurolysis only, 3 underwent nerve transfer, 2 underwent nerve grafting (1 autologous, 1 processed nerve allograft). The mean time frame from presentation to operation was 13 months. MRC grading of shoulder function increased from a mean MRC 2 to 4 at a mean of 8 months post-operatively. DASH scores of the 7 participating patients were 30.8 at a mean of 47 months post-operatively. 2 patients had experienced a sensory deficit. Conclusions Nerve grafting allows bridging of a gap when the injury is well defined with a suitable window for re-innervation. Allograft has a role in small gaps where there may be concerns with autograft. Nerve transfer may allow earlier re-innervation and be a more reliable option where the proximal extent of nerve injury is poorly defined. We found nerve wraps to be a useful addition when an injured nerve may be adherent to a heavily scarred bed. We will present some worked examples along with a potential algorithm for a surgical strategy.

Transfer of the anterior C3 levator scapulae motor nerve branch for spinal accessory nerve injury: illustrative case.

BACKGROUNDInjury to the spinal accessory nerve (Acc) results in loss of motor function of the trapezius muscle and leads to severe shoulder problems. A vast number of surgical strategies have been proposed to reinnervate (suture, grafting, and nerve transfers) or compensate (tendon and muscle transfers) the lost function of the trapezius muscle.OBSERVATIONSThe authors report a successful case of Acc reconstruction 5 months after the injury with the anterior C3 levator scapulae motor nerve branch transfer in omotrapezoid triangle of the neck.LESSONSThe advantages of the proposed technique over preexisting nerve transfers were discussed. We believe that this technique can be considered as an alternative to already existing techniques for proximal injuries to Acc.

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

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. 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. 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. 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.

Treatment of Pain Due to Winged Scapula with Spinal Cord Stimulation: A Case Report

BACKGROUND: Winged scapula (WS) is a protrusion of the scapula giving the appearance of a wing and can be due to either a musculoskeletal or neurological insult. Pain associated with WS is multifactorial, including myofascial and neuronal mechanisms, and may be difficult to treat. CASE REPORT: In a case of WS refractory to conservative management with physical therapy and medications and not a candidate for nerve repair, we treated the pain with a spinal cord stimulator. We report significant pain reduction and improvement in function with the procedure. CONCLUSION: This case suggests a role for neuromodulation in WS and requires further investigation. KEY WORDS: Winged scapula, spinal accessory nerve injury, spinal cord stimulation, neuromodulation

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.

The Modified Eden-Lange Tendon Transfer for Lateral Scapular Winging Secondary to Spinal Accessory Nerve Injury

Trapezius paralysis following injury to the spinal accessory nerve can be a debilitating complication resulting from lymph node biopsy, radical neck dissection, or penetrating trauma in the region of the posterior cervical triangle. Disruption of the delicate muscular balance in the shoulder girdle may result in lateral scapular winging, ipsilateral upper extremity radiculopathy, and limited shoulder function and range of motion. Spontaneous recovery with nonoperative management is possible in some patients, and restoration of function after reparative neural procedures has been observed in patients undergoing timely repair. However, extended delays from the time of injury to surgery are common and may necessitate various muscle transfers to reestablish the complex biomechanics and balance of the shoulder girdle. We describe a modification to the classic Eden-Lange procedure with lateral transfer of the levator scapulae and rhomboid minor to the scapula spine and rhomboid major transfer with a small wafer of bone to the scapula body for chronic lateral winging of the scapula following injury to the spinal accessory nerve as the result of a cervical lymph node biopsy.

Idiopathic spinal accessory nerve injury

Palsy of the eleventh cranial nerve – or spinal accessory nerve (SAN) − is a rare cause of scapular winging, leading to painful upper extremity disability due to weakness and atrophy of the trapezius muscle. Most SAN injuries are iatrogenic, and no specific pediatric epidemiology is known.Herein is described the case of a 17-year-old adolescent referred to Physical and Rehabilitation Medicine consultation due to insidious right shoulder pain with two years of evolution.Shoulder pain combined with muscular atrophy is suggestive of nerve lesion. Electromyography is the gold standard exam and showed segmental demyelination and axonotmesis in this case. After evaluation, the patient underwent physiotherapy, with excellent results.In conclusion, SAN injury treatment can be conservative or surgical and physiotherapy is the basis of early treatment in most cases. Recovery can occur even after a significant period of time.

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

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. 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 6months. 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). 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. 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.

경부 림프절 절제생검술 후 상완신경총 손상으로 오진된 척수부신경 손상 1예

경부 림프절 절제생검술 후 상완신경총 손상으로 오진된 척수부신경 손상 1예

P86-T Iatrogenic spinal accessory nerve (SAN) injury

SAN injury produces considerable disability. The most common cause is an inability to localize the nerve during neck surgeries. Recognizing the injury promptly is crucial for a better prognosis. We describe and analyze SAN injuries seen at our electromyography (EMG) laboratory during a period of four years. We present 6 cases of SAN injury; all of them because of iatrogenic damage during neck surgery. These surgeries did not proceed with intraoperative neurophysiological monitoring (IONM). The most common procedure was cervical lymphadenectomy (4 patients). The lapse of time since the damage until the first suspicion of neurogenic damage ranged from 0 to 7 months; only in 1 case the damage was detected in situ and in 2 patients after 7 months. We performed the first EMG 1 year after the injury in 3 patients; in the remaining 3 cases after 8, 4 and 2 months. None of our patients underwent reconstructive surgery. Their evolution was dissatisfactory: bad in 2 patients and very bad in 4. 3 patients suffered further musculoskeletal complications. 4 of our 6 patients worked before the SAN injury, 3 of whom were unable to work again. All the cases of SAN injury we saw during a period of four years were due to iatrogenic damage during neck surgeries – none of them were carried out with IONM. The diagnosis was late in most of our patients and this contributed to worsen the prognosis. IONM in these procedures would prevent injury and would allow early detection of the damage.

Spinal Accessory Nerve Injury Induced by Manipulation Therapy: A Case Report.

Spinal accessory nerve (SAN) injury mostly occurs during surgical procedures. SAN injury caused by manipulation therapy has been rarely reported. We present a rare case of SAN injury associated with manipulation therapy showing scapular winging and droopy shoulder. A 42-year-old woman visited our outpatient clinic complaining of pain and limited active range of motion (ROM) in right shoulder and scapular winging after manipulation therapy. Needle electromyography and nerve conduction study suggested SAN injury. Physical therapy (PT) three times a week for 2 weeks were prescribed. After a total of 6 sessions of PT and modality, the patient reported that the pain was gradually relieved during shoulder flexion and abduction with improved active ROM of shoulder. Over the course of 2 months follow-up, the patient reported almost recovered shoulder ROM and strength as before. She did not complain of shoulder pain any more.