Hypoglossal Nerve Palsy Recovery After Carotid Endarterectomy
Most hypoglossal nerve injuries after carotid endarterectomy recover completely within 4 months, though some patients may have residual deficits at one year. 1
Expected Recovery Timeline
Complete recovery typically occurs within 4 months in the majority of patients. 1 The evidence demonstrates:
- Most cranial nerve injuries show improvement within a few weeks and resolve without residual disability at follow-up periods ranging from 2 weeks to 14 months 2
- All cranial nerve palsies demonstrate excellent spontaneous recovery rates within one year 3
- However, residual hypoglossal nerve deficit persists at one year in approximately 15% of affected patients (4 out of 26 nerve injuries in one series) 1
Incidence and Context
The hypoglossal nerve is the most commonly injured cranial nerve during carotid endarterectomy:
- Hypoglossal nerve injury occurs in 2.6-3.3% of carotid endarterectomy procedures 2
- Overall cranial nerve injury rate ranges from 5.6-15.1% across multiple studies 1, 2
- Permanent hypoglossal nerve damage (>12 months) occurs in only 1.4% of all CEA patients 4
Mechanism and Prognosis
The mechanism of injury determines recovery potential:
- Transient injuries result from trauma during dissection, retraction, or carotid clamping rather than nerve transection 2
- Neuropraxic injuries (stretch, compression, edema) have excellent recovery potential 3
- Direct surgical trauma or complete nerve division would have worse prognosis, though this is uncommon with proper surgical technique 1
Clinical Management
Patients with hypoglossal nerve dysfunction should undergo thorough otolaryngological evaluation and long-term follow-up 2:
- Monitor for dysarthria and tongue deviation to the affected side upon protrusion 5
- Assess swallowing function and aspiration risk
- Serial examinations at 3-6 months and 12-18 months postoperatively 4
Important Caveats
If bilateral carotid surgery is planned, complete recovery of the first side must be documented before proceeding with contralateral surgery, as bilateral hypoglossal nerve injury is potentially life-threatening 4. The risk is particularly relevant since carotid endarterectomy causes recurrent laryngeal nerve damage in 4-7% of cases 6, and bilateral vocal cord paralysis would require tracheostomy.