What is the most commonly injured cranial nerve during carotid (carotid artery) endarterectomy (surgical procedure to remove plaque from the carotid artery)?

Hypoglossal Nerve (XII) is the Most Commonly Injured Cranial Nerve During Carotid Endarterectomy

The hypoglossal nerve (CN XII) is the most commonly injured cranial nerve during carotid endarterectomy procedures. 1, 2

Incidence of Cranial Nerve Injuries During Carotid Endarterectomy

According to research evidence, the pattern of cranial nerve injuries during carotid endarterectomy shows:

• Hypoglossal nerve (XII): 3.3% of cases 2
• Vagus nerve (X): 2.6% of cases (manifesting as vocal cord paralysis) 2
• Glossopharyngeal nerve (IX): 0.7% of cases 2
• Facial nerve (VII): 0.4% of cases (specifically the marginal mandibular branch) 2

Risk Factors for Hypoglossal Nerve Injury

The American Heart Association and American College of Radiology guidelines highlight several risk factors that increase the likelihood of hypoglossal nerve injury during carotid endarterectomy:

• High carotid bifurcation requiring more extensive dissection 1
• Atheromatous lesions extending into the internal carotid artery beyond the exposed surgical field 1
• Reoperative carotid endarterectomy due to accumulated scar tissue 1
• Lesions at or above the level of the second cervical vertebra 1
• Prior neck surgery or radiation therapy 1

Clinical Presentation of Hypoglossal Nerve Injury

Patients with hypoglossal nerve injury typically present with:

• Tongue deviation toward the affected side when protruded
• Dysarthria
• Difficulty with mastication
• Dysphagia 1

Prevention of Cranial Nerve Injuries

The American College of Surgeons recommends several strategies to minimize the risk of cranial nerve injuries during carotid endarterectomy:

• Thorough knowledge of regional anatomy 1
• Careful surgical technique with gentle tissue handling 1
• Identification and protection of cranial nerves during dissection 1
• Avoidance of excessive retraction 1
• Preoperative planning for patients with high-risk anatomical features 1

Prognosis

Most cranial nerve injuries following carotid endarterectomy are transient and show improvement within weeks 1, 2. In the study by 2, all patients with cranial nerve injuries showed improvement within a few weeks, and none had residual disability at the last follow-up (two weeks to 14 months).

Important Considerations

• Contralateral laryngeal nerve palsy is a relative contraindication to carotid endarterectomy, as bilateral nerve palsies could compromise the airway 1
• Patients manifesting symptoms of cranial nerve dysfunction should undergo a thorough otolaryngological evaluation and long-term follow-up 2