Accessory nerve injury

Introduction to accessory nerve injury The paraspinal spinal cord is derived from the dorsolateral nucleus of the dorsolateral side of the anterior horn cell group of the neck 1 to 5 or the neck 1 to 6. The fibers emitted by the nucleus are pierced from the lateral side of the spinal cord and merged into a total trunk. The ligament and the posterior root of the spinal nerve rise up, enter the cranium through the occipital foramen, and meet with the medullary fibers. After the jugular foramen is separated from the medullary canal, it descends to the neck and moves between the neck and the vein. The sternocleidomastoid muscle descends deeply, and the branch occupies the sternocleidomastoid muscle. The trunk penetrates into the posterior triangle of the posterior margin of the sternocleidomastoid muscle, and sneaked down into the deep trapezius muscle to innervate the muscle. . If the accessory nerve is injured immediately after exiting the jugular foramen, it is often injured at the same time as other adjacent cranial nerves. In the neck, the accessory nerve is particularly prone to injury due to its shallow position across the posterior triangle of the neck. Contusion and firearm injuries are rare. The most common is surgical injury. When the lesion only invades the medullary nucleus of the accessory nerve. When the silk is present, the symptoms are the same as when the vagus nerve is damaged, without the symptoms of the neck muscles. basic knowledge The proportion of illness: 0.3% - 0.5% Susceptible people: no special people Mode of infection: non-infectious Complications: Facial nerve injury Tumors of the origin of the paraganglia

Cause of accessory nerve injury

Causes

Common causes of accessory nerve injury are:

1. Peripheral damage:

Iatrogenic injury (12%):

Because of the neck surgery, the extracranial segment of the accessory nerve is damaged. Among them, the accidental injury caused by lymph node biopsy or removal of the posterior triangle is the most common, the incidence rate is 3% to 6%, and some occur in the neck tumor resection and neck. Injury in arterial surgery.

Skull base fracture (15%):

In the case of craniocerebral traumatic skull base fracture, the fracture line through the occipital condyle involving the jugular foramen can cause contusion or compression of the jugular vein segment and the intracranial segment.

Skull base gunshot wound (10%):

Can directly cause para-neural damage.

Tumor infiltration or compression (16%):

Such as cervical lymph node tuberculosis, cervical malignant tumor can cause extracranial segmental injury of the paraganglia; occipital macropore area and cerebral cerebral horn area tumor can cause jugular vein hole segment and intracranial segment injury.

Other (20%):

Malformation of the cranial-cervical junction area, arachnoid arachnoiditis, jugular phlebitis, multiple encephalitis, etc. can cause peripheral damage of the accessory nerve.

2. Nuclear injury: Nuclear acute injury is common in medullary hemorrhage or infarction and inflammation. Chronic injury is common in medullary and syringomyelia, brain stem tumor, and high cervical intramedullary tumor.

Paraneoplastic injury prevention

The extracranial segmental injury of the accessory nerve is mainly caused by surgical injury in the posterior triangle of the neck. Occasionally, the injury caused by neck impact is reported. The accessory nerve injury has a great influence on the function of the upper limb. Wright reported that 8 cases of paraneoplastic injury occurred in 4 cases of cancer. After resection, 4 cases were caused by lymph node biopsy of the sternocleidomastoid muscle. Seddon reported 14 cases of paraneoplastic injury, 8 cases were caused by surgical injury in the posterior triangle, and 6 cases were caused by open neck injury.

Nakamich reported that 7 cases of 7 cases of paraneoplastic injury were caused by cervical lymph node biopsy, and 1 case was caused by cervical ammunition. Of the 53 cases reported in China, 44 cases were lymph node biopsy of the posterior triangle, and 4 cases were foreign bodies. For example, the posterior cervical hemangioma was resected, 4 cases were caused by neck trauma, and the accessory nerve was obliquely posterior to the distal side of the skull. It can be found in the upper edge of the sternocleidomastoid muscle, which is shallow and the trunk is thin. Regardless of cervical lymph node biopsy or other operations can be caused, should be highly valued, adequate intraoperative exposure, to prevent blind clamping, ligation or cutting, do not pull too heavy or cause hematoma formation, surgical damage to the accessory nerve can be completely avoided of.

Paraneoplastic injury complications Complications facial nerve injury

The accessory nerve is injured immediately after exiting the jugular foramen, often with other nearby cranial nerves. In the neck, the accessory nerve is particularly prone to injury due to its shallow position across the posterior triangle of the neck. Contusion and firearm injuries are rare. The most common is surgical injury. When the lesion only invades the medullary nucleus of the accessory nerve. When the silk is present, the symptoms are the same as when the vagus nerve is damaged, without the symptoms of the neck muscles.

Symptoms of paraneoplastic injury Common symptoms Muscle atrophy, weakness, cranial nerve palsy, bulbar palsy, brainstem lesion

When the side of the accessory nerve spinal cord is damaged or its spinal cord nucleus is damaged, the ipsilateral sternocleidomastoid and trapezius tendon have atrophy. Because the contralateral sternocleidomastoid muscle predominates, the squat turns to the patient during calmness. Side, while the force on the contralateral side of the head is weak, the affected side of the shoulder drooping, can not shrug, the scapula position is skewed, and the muscles it squashed, due to the displacement of the scapula, the brachial plexus is chronically pulled, causing Side upper limb lifting and abduction are restricted.

In the late stage, due to scar stimulation, spasmodic contracture (rose neck) deformity can occur. When bilateral lesions occur, the patient's head and neck are back and forward flexion, the parasacral nerve injury caused by skull base fracture or gunshot wound, jugular vein hole lesion, and occipital foramen Area lesions, cerebral cerebellopontine angle lesions and para-neural lesions caused by extensive lesions of the skull base and nucleus pulposus often occur simultaneously with the posterior group of cranial nerves and other cranial nerve damage, while brain stem nucleus, brain nerve damage Often multiple groups and bilateral.

Examination of accessory nerve injury

Neuroimaging can be used, and electrophysiology can help diagnose.

1. Neuroimaging: When the paraneoplastic injury is caused by a skull base tumor or a brain stem lesion, imaging examinations such as CT and MRI are helpful for the diagnosis of the primary disease.

2. Electromyography examination: It shows that the insertion potential of the trapezius muscle and the sternocleidomastoid muscle is prolonged or no electrical response is induced, and the diagnosis of the accessory nerve injury can be established.

Diagnosis and identification of accessory nerve injury

Positioning diagnosis

(1) Diagnosis of the injury of the paraspinal spinal cord neck: There is shoulder discomfort, weakness or pain after neck surgery, difficulty in shrugging shoulders, shoulder lift below 90°, shoulder sagging, traction feeling, trapezius muscle atrophy, While other muscle strengths and sensations were normal, electromyography examined abnormalities in the trapezius and sternocleidomastoid muscles.

(2) Diagnosis of the accessory nerve skull base area and brain stem nuclear injury: the skull base fracture, the skull base tumor or other lesions caused by the accessory nerve alone is extremely rare, and one side of the posterior group brain nerve is involved at the same time, according to the lesion The location and nature can also be combined with other signs of cranial nerve damage. The paraspinal lesions caused by brain stem lesions are often manifested as bulbar palsy. CT and MRI imaging studies are helpful for the diagnosis of primary diseases.

2. Diagnosis of combined injury: It should be clear whether it is a simple injury of the accessory nerve or other brain damage. If it occurs simultaneously with the brain and other brain damage of the posterior group, it can be expressed as:

(1) Avellis syndrome: vagus nerve and accessory nerve medial branch injury.

(2) Jackson syndrome: vagus nerve, accessory nerve and sublingual nerve damage.

(3) Schmidt syndrome: vagus and accessory nerve damage.

(4) Collet-Sicard syndrome: glossopharyngeal nerve, vagus nerve, accessory nerve, hypoglossal nerve paralysis.

(5) Jugular vein syndrome (Vernet syndrome): glossopharyngeal nerve, vagus nerve, paraneocephalic nerve palsy.

(6) Others: cerebellopontine angle syndrome, occipital macroporous syndrome, unilateral skull syndrome (Garcin syndrome or Guillain-Garcin syndrome, complete or incomplete).

3. Etiology diagnosis : Looking for the cause of accessory nerve injury.

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