Surgical anatomy of spinal accessory nerve: is trapezius functional deficit inevitable after division of the nerve?

The course of spinal accessory nerve in the posterior triangle, the innervation of the sternocleidomastoid and trapezius muscles and the contributions from the cervical plexus were studied in 20 cadaveric dissections. The nerve was most vulnerable to iatrogenic injuries after leaving the sternocleidomastoid. Direct innervation of trapezius by cervical plexus branches was noted in five dissections, whereas connections between the cervical plexus and the spinal accessory nerve were observed in 19 dissections. These were usually under the sternocleidomastoid (proximal to the level of division of the nerve in nerve transfer procedures). Although the contribution from the cervical plexus to trapezius innervation is considered minimal, trapezius function can be protected in neurotization procedures by transecting the spinal accessory nerve distal to its branches to the upper position of trapezius.     

Surgical anatomy of the spinal accessory nerve in the posterior triangle of the neck

OBJECTIVE: The major complication of neck dissection and surgery at the posterior triangle of the neck is severe disability of the shoulder or "shoulder syndrome", which results from spinal accessory nerve injury. Surgical landmarks of the nerve in this area were studied. METHODS: Fifty-six fresh Thai cadavers (112 necks) were dissected to identify the anatomical relationship of the spinal accessory nerve and its commonly used landmarks. RESULTS: The spinal accessory nerve was found within 3.6 cm (mean, 1.43 cm) above Erb's point. The distance between the spinal accessory nerve entering the trapezius muscle and the clavicle was between 2.6 cm and 6.9 cm (mean, 4.5 cm). CONCLUSION: Our data were different from those described in the literature. Reconsideration of these two important landmarks can help to minimize iatrogenic injury of the spinal accessory nerve.     

A technique for preservation of spinal accessory nerve function in radical neck dissection

A new technique is described that preserves trapezius muscle function in radical neck surgery while cutting that part of the spinal accessory nerve which courses through the sternocleidomastoid muscle. The technique takes advantage of the little-known fact that, in humans, the trapezius muscle has dual innervation. The C2-3-4 motor root is joined to the distal portion of the spinal accessory nerve to give motor function to the trapezius muscle. This procedure will save shoulder mobility in the majority of patients who undergo radical neck dissection. The technique is accomplished rapidly with the use of the gastrointestinal stapler in the scalene fat pad.     

Iatrogenic spinal accessory nerve injury in children

Injury to the spinal accessory nerve in the posterior triangle of the neck results in trapezius paralysis and shoulder dysfunction. The most common etiology is iatrogenic and has been reported extensively in adults. We report 3 cases of spinal accessory nerve injury recognized postoperatively in children and discuss the microsurgical treatment, results, and simple strategies to avoid this complication.     

Spinal accessory nerve injury

Injury to the spinal accessory nerve can lead to dysfunction of the trapezius. The trapezius is a major scapular stabilizer and is composed of three functional components. It contributes to scapulothoracic rhythm by elevating, rotating, and retracting the scapula. The superficial course of the spinal accessory nerve in the posterior cervical triangle makes it susceptible to injury. Iatrogenic injury to the nerve after a surgical procedure is one of the most common causes of trapezius palsy. Dysfunction of the trapezius can be a painful and disabling condition. The shoulder droops as the scapula is translated laterally and rotated downward. Patients present with an asymmetric neckline, a drooping shoulder, winging of the scapula, and weakness of forward elevation. Evaluation should include a complete electrodiagnostic examination. If diagnosed within 1 year of the injury, microsurgical reconstruction of the nerve should be considered. Conservative treatment of chronic trapezius paralysis is appropriate for older patients who are sendentary. Active and healthy patients in whom 1 year of conservative treatment has failed are candidates for surgical reconstruction. Studies have shown the Eden-Lange procedure, in which the insertions of the levator scapulae, rhomboideus minor, and rhomboideus major muscles are transferred, relieves pain, corrects deformity, and improves function in patients with irreparable injury to the spinal accessory nerve.     

Surgical management of trapezius palsy

BACKGROUND: Injury to the spinal accessory nerve in the posterior cervical triangle leads to paralysis of the trapezius muscle. The aim of this study was to determine the indications for nerve repair or reconstructive surgery according to the etiology, the duration of the preoperative delay, and specific patient characteristics. METHODS: Of twenty-seven patients with a trapezius palsy, twenty were treated with neurolysis or surgical repair (direct or with a graft) of the spinal accessory nerve and seven were treated with the Eden-Lange muscle transfer procedure. Lymph node biopsy was the main cause of the nerve injury. The nerve repairs were performed at an average of seven months after the injury, and the reconstructive procedures were done at an average of twenty-eight months. Nerve repair was performed for iatrogenic injuries of the spinal accessory nerve, within twenty months after the onset of symptoms, and in one patient with spontaneous palsy. Reconstructive surgery was performed for cases of trapezius palsy secondary to radical neck dissection, for spontaneous palsies, and after failure of nerve repair or neurolysis. The mean follow-up period was thirty-five months. The functional outcome was assessed clinically on the basis of active shoulder abduction, pain, strength of the trapezius on manual muscle-testing, and level of subjective patient satisfaction. RESULTS: The results were good or excellent in sixteen of the twenty patients treated with nerve repair and in four of the seven patients treated with the Eden-Lange procedure. Poor results were seen in older patients and in patients with a previous radical neck dissection. CONCLUSIONS: Good results can be expected from a repair of the spinal accessory nerve if it is performed within twenty months after the injury, as the nerve is basically a purely motor nerve and the distance from the injury to the motor end plates is short. Muscle transfer should be performed in patients with spontaneous trapezius palsy, when previous nerve surgery has failed, or when the time from the injury to treatment is over twenty months. Treatment is less likely to succeed when the patient is older than fifty years of age or the palsy was due to a radical neck dissection, penetrating injury, or spontaneous palsy.     

Iatrogene Läsion des Nervus accessorius bei der cervicalen Lymphknotenbiopsie

The majority of lesions of the spinal accessory nerve occur as an iatrogenic injury after lymph node biopsy in the posterior cervical triangle (trigonum colli laterale). In most cases the accessory nerve palsy is not recognised immediately after the injury. Therefore surgical repair is often performed too late to regain sufficient function of the paralytic trapezius muscle. Later than 6 months after the injury, reconstruction seems to be hopeless. However, "timely" reconstructions often have poor results. Exact knowledge of anatomy, postoperative check of the trapezius muscle and, if an accessory nerve injury has occurred, early reconstructive procedures (neurolysis, reconstruction of nerve continuity) may on the one hand prevent iatrogenic lesions of the nerve and on the other hand improve the reconstructive result. A series of 6 patients with an injury of the spinal accessory nerve after lymph node biopsy is reported. In 2 cases primary coaptation, in 3 cases interpositional nerve grafting and in 1 case neurotization was performed. Clinical recovery was achieved in 3 of the 6 cases.     

Suprascapular nerve release for treatment of shoulder and periscapular pain following intracranial spinal accessory nerve injury

Iatrogenic injury to the spinal accessory nerve is one of the most common causes of trapezius muscle palsy. Dysfunction of this muscle can be a painful and disabling condition because scapular winging may impose traction on the soft tissues of the shoulder region, including the suprascapular nerve. There are few reports regarding therapeutic options for an intracranial injury of the accessory nerve. However, the surgical release of the suprascapular nerve at the level of the scapular notch is a promising alternative approach for treatment of shoulder pain in these cases. The author reports on 3 patients presenting with signs and symptoms of unilateral accessory nerve injury following resection of posterior fossa tumors. A posterior approach was used to release the suprascapular nerve at the level of the scapular notch, transecting the superior transverse scapular ligament. All patients experienced relief of their shoulder and scapular pain following the decompressive surgery. In 1 patient the primary dorsal branch of the C-2 nerve root was transferred to the extracranial segment of the accessory nerve, and in the other 2 patients a tendon transfer (the Eden-Lange procedure) was used. Results from this report show that surgical release of the suprascapular nerve is an effective treatment for shoulder and periscapular pain in patients who have sustained an unrepairable injury to the accessory nerve.     

The anatomy of the accessory nerve and cervical lymph node biopsy

Injury to the accessory nerve is the most frequent complication of surgical procedures in the posterior triangle of the neck. The symptoms produced by paralysis of the trapezius are disabling. The components of this disability are pain, limitation of abduction, and drooping of the affected shoulder. A detailed knowledge of the course of the nerve and its anatomic relations are essential in avoiding injury. Useful anatomic landmarks are the proximal internal jugular vein in the anterior triangle and Erb's point in the posterior triangle. Prevention of accessory nerve injury is the best management. The indications for lymph node biopsies in the neck should be sound. The use of a general anesthetic without paralysis is recommended if an excisional biopsy is necessary. Adequate exposure is essential. Whether the nerve needs to be identified in all cases has to be individualized and requires careful judgment. A divided or injured nerve is best managed with primary repair within 3 months of injury.     

颈7神经根后股与副神经移位吻合重建斜方肌功能

目的探讨一种根治性颈淋巴清扫术（radical neck dissection，RND）中采用神经移位吻合改善术后肩功能的方法。方法1999年3月～2001年2月，10例需行RND的患者，行RND时保留远颅端至斜方肌前缘的副神经，长度〉3cm，待RND完成后，解削分离出C7神经，并将其后股切断，长度3～5cm，在无张力下行两神经端端吻合。患者在术前和术后1、6及12个月行临床的斜方肌功能客观评价及肌电检测。结果经c，神经根后股与副神经移位吻合后，各部肌电恢复率1、6及12个月分别为上部9．8％、68．9％、73．5％；中部4．7％、73．6％、69．4％；下部6．2％、70．5％、70．3％；7例患者上臂外展超过90。，上肢平均最大外展角度超过95。，肌萎缩较轻，均为1～2级，肩外展受限2级7例．3级3例。结论RND中采用C7神经根后股与副神经移位吻合能较好地重建斜方肌功能。供、受区位于同一术区内，仅有一个吻合口，减少手术创伤。C7神经根后股的切断对手臂运动及感觉功能无影响。     

Reinnervation of the trapezius muscle

The eleventh cranial nerve shoulder syndrome, which results from denervation of the trapezius muscle, contributes significantly to the postoperative morbidity of radical neck dissections. Multiple techniques exist for the reinnervation of muscles that have injured motor nerves. Reinnervation of denervated trapezius muscles was examined in the New Zealand white rabbit by use of three techniques of reinnervation: (1) neuromuscular pedicle transfer of the accessory nerve from the trapezius muscle, (2) direct accessory nerve implantation, and (3) neuromuscular pedicle transfer of the accessory nerve from the sternocleidomastoid muscle. The reinnervated trapezius muscles were examined grossly by direct nerve stimulation, electrophysiologically by evoked electromyography, and histologically by enzymatic muscle staining and silver-reducing nerve staining. The gross, electrophysiologic, and histologic results confirmed successful reinnervation of the trapezius muscle within 6 weeks of operation. No significant difference was observed between the various techniques of reinnervation.     

The modifed Eden-Lange procedure for paralysis of the trapezius muscle

Trapezius muscle paralysis results from injury to the spinal accessory nerve. Impairment in the trapezius muscle function may destabilize the muscle resulting in winged scapula. A 25-year-old university student who was active in sports had complaints of shoulder drop and pain on abduction. He had a three-year history of fall resulting in a scapular fracture for which he received conservative treatment. Physical examination showed asymmetry and drop of the right shoulder. Lateral scapular winging was apparent particularly above 90 degrees of abduction. Electromyography revealed isolated paralysis of the trapezius muscle. The patient underwent reconstruction with the modified Eden-Lange procedure. After a two-year follow-up, asymmetry in the shoulder decreased, there was no pain on active abduction, and the patient returned to active sports and was fully satisfied with the outcome.     

A cadaveric study of the motor nerves to the levator scapulae muscle

Understanding the surgical anatomic relationships of the motor nerves to the levator scapulae muscle is imperative for reducing postoperative shoulder dysfunction in patients undergoing neck dissection. To elucidate this relevant anatomy, cervical (C3, C4) and brachial (C5 via dorsal scapular nerve) plexi contributions to the levator scapulae were assessed with respect to posterior triangle landmarks in 37 human cadaveric necks. An average of approximately 2 (actual 1.92) nerves from the cervical plexus (range 1 to 4 nerves) emerged from beneath the posterior border of the sternocleidomastoid muscle in a cephalad to caudad progression to enter the posterior triangle of the neck on their way to innervating the levator scapulae. These cervical plexus contributions exhibited a fairly regular relationship to the emergence of cranial nerve XI and the punctum nervosum along the posterior border of the sternocleidomastoid muscle. After emerging from the posterior border of the sternocleidomastoid to enter the posterior triangle of the neck, cervical plexus contributions to the levator scapulae traveled for a variable distance posteriorly and inferiorly, sometimes branching or coming together. Ultimately these nerves crossed the anterior border of the levator scapulae as 1 to 3 nerves (average 1.94) in a regular superior to inferior progression. The dorsal scapular nerve from the brachial plexus exhibited highly variable anatomic relations in the inferior aspect of the posterior triangle, and was found to penetrate or give branches to the levator scapulae in only 11 of 35 neck specimens. We have found that the levator scapulae receives predictable motor supply from the cervical plexus. Our data elucidate surgical anatomy useful to head and neck surgeons. (Otolaryngol Head and Neck Surg 1997;117:671-80.)     

Accessory nerve palsy following thoracotomy

A previously unreported cause of 11th cranial nerve palsy is described in a 53-year-old man. Dysfunction of the trapezius branch of the spinal accessory nerve occurred following median sternotomy and was documented by electromyography. This injury resulted in dysfunction of the trapezius muscle with loss of support of the shoulder girdle and pain. The injury may have been due to stretching from sternal retraction or injury secondary to internal jugular venous cannulation.     

后入路副神经移位至肩胛上神经的应用解剖

目的 对斜方肌内的神经支配进行解剖学观察,为寻找副神经移位到肩胛上神经的最佳移位点和移位方式提供解剖依据.方法 选用成人尸体标本10具20侧.观察副神经在斜方肌内的行径及分支.并取不同水平副神经、肩胛上神经横断面制病理切片,计数各神经断面的神经纤维数,进行比较.结果 副神经在锁骨上2～3 cm进入斜方肌内,在肩胛冈中点前上方3～4 cm处,有来自颈丛的交通支加入后形成终末支.副神经的神经纤维计数:入斜方肌处(A点)为(1245±46)条,颈丛的交通支汇入前(B点)为(830±36)条,汇入后(C点)为(1074±38)条.结论 (1)副神经在与颈丛交通支合干后H-G段内的各断点,是副神经的最佳移位点.(2)后进路副神经移位术不影响斜方肌上部神经支配,充分利用了颈丛交通支,且缩短了神经再生距离,值得推广.     

Transfer of the accessory nerve to the suprascapular nerve in brachial plexus reconstruction

PURPOSE: Transfer of the accessory nerve to the suprascapular nerve is a common procedure, performed to reestablish shoulder motion in patients with brachial plexus palsy. We propose dissecting both nerves via a distal oblique supraclavicular incision, which can be prolonged up to the scapular notch. The results of the transfer to the suprascapular nerve are compared with those of the combined repair of the suprascapular and axillary nerves. METHODS: Thirty men between the ages of 18 and 37 years with brachial plexus trauma had reparative surgery within 3 to 10 months of their injuries. In partial injuries with a normal triceps, a triceps motor branch transfer to the axillary nerve was performed. The suprascapular and accessory nerves were dissected via an oblique incision, extending from the point at which the plexus crosses the clavicle to the anterior border of the trapezius muscle. In 10 patients with fractures or dislocations of the clavicle, the trapezius muscle was partially elevated to expose the suprascapular nerve at the suprascapular notch. RESULTS: In all cases, transfer of the accessory to the suprascapular nerve was performed without the need for nerve grafts. A double lesion of the suprascapular nerve was identified in 1 patient with clavicular dislocation. In those with total palsy, the average improvement in range of abduction was 45 degrees , but none of the patients with total palsy recovered any active external rotation. Patients with upper-type injury recovered an average of 105 degrees of abduction and external rotation. If only patients with C5-C6 injuries were considered, the range of abduction and external rotation increased to 122 degrees and 118 degrees , respectively. CONCLUSIONS: Use of the accessory nerve for transfer to the suprascapular nerve ensured adequate return of shoulder function, especially when combined with a triceps motor branch transfer to the axillary nerve. The supraclavicular exposure proposed here for the suprascapular and accessory nerves is advantageous and can be extended easily to explore the suprascapular nerve at the scapular notch.     

Accessory nerve injury

A series of 13 patients with an injury of the accessory nerve in the posterior cervical triangle is reported. In 11 patients the nerve was damaged during a lymph node biopsy and in two cases there was a sharp glass injury. Paralysis of the trapezius muscle occurred with resulting deformity and loss of function of the shoulder. Nine patients were operated on. In five cases neurolysis, in two cases neurorrhaphy and in two cases reconstruction with a sural nerve graft were performed 3-17 months after the injury. The result was good or fair in six operative cases. Five of these were neurolyses.

In one instance good and in three cases fair recovery was achieved without operation. All but one of the patients were able to return to their former employment. The mean follow-up time was 20 months.