What is the management of recurrent laryngeal nerve (RLN) injury after anterior cervical spine surgery?

Management of Recurrent Laryngeal Nerve Injury After Anterior Cervical Spine Surgery

Patients with recurrent laryngeal nerve (RLN) injury after anterior cervical spine surgery require prompt otolaryngology consultation with laryngoscopy for diagnosis, followed by a combination of conservative management with voice therapy, steroids, and close monitoring, with most cases resolving within 3-6 months. 1, 2

Incidence and Presentation

• Recurrent laryngeal nerve paralysis occurs in 1.27% to 2.7% of anterior cervical spine surgeries, though laryngoscopy reveals a higher incidence with hoarseness affecting up to 50% of patients immediately after surgery 1
• Symptoms typically include hoarseness, dysphagia, and in bilateral cases, potential airway compromise 1
• Most cases present immediately postoperatively, but delayed onset (2-3 days after surgery) can occur in rare cases 2
• Right-sided approaches carry higher risk of RLN injury (13.3%) compared to left-sided approaches (6.5%) due to anatomical differences in nerve course and redundancy 3, 4

Diagnostic Approach

• Prompt otolaryngology consultation with flexible laryngoscopy is essential for any patient with postoperative hoarseness to confirm vocal cord paralysis 1
• Laryngoscopy should be performed both preoperatively and postoperatively in high-risk cases to document baseline vocal cord function 1
• MRI may be useful for evaluating the entire course of affected nerves in complex cases 5

Management Algorithm

Immediate Management (0-72 hours)

1. Prompt otolaryngology consultation with flexible laryngoscopy for any patient with postoperative hoarseness 1

2. For unilateral paralysis:

   • Initiate short course of corticosteroids (typically 1 week) 2
   • Voice rest and hydration 1
   • Speech therapy referral for compensatory techniques 1

3. For bilateral paralysis:

   • Immediate airway assessment and possible tracheostomy if respiratory distress is present 1
   • ICU monitoring for respiratory compromise 1

Intermediate Management (1-6 months)

1. Follow-up laryngoscopy at 4-6 weeks to assess recovery 1
2. Voice therapy continuation with focus on compensatory techniques 1
3. For persistent unilateral paralysis beyond 3 months:
   • Consider vocal fold injection (temporary) with materials such as collagen or hyaluronic acid for symptomatic patients 1

Long-term Management (>6 months)

1. For permanent unilateral paralysis:

   • Consider more definitive procedures such as medialization thyroplasty or arytenoid adduction for persistent symptomatic dysphonia 1
   • Continued voice therapy for optimization of remaining function 1

2. For permanent bilateral paralysis:

   • Tracheostomy may be required long-term 1
   • Consider posterior cordotomy or arytenoidectomy to improve airway while preserving voice 1

Prevention Strategies

• Use left-sided approach when possible, as it reduces RLN injury risk from 13.3% (right-sided) to 6.5% 3, 4
• Monitor and reduce endotracheal tube cuff pressure to below 20 mmHg during retractor placement, which can further reduce RLN injury rates to 1.3% 3, 6
• Intermittent release of retractors during lengthy procedures to prevent prolonged nerve compression 6, 7
• Careful documentation of nerve identification and integrity in surgical reports 1

Prognosis

• Approximately 90% of RLN injuries after anterior cervical spine surgery are temporary, with most resolving within 3-6 months 6
• Permanent RLN palsy occurs in approximately 10% of cases 6
• Early diagnosis and management improve outcomes and quality of life 1

Common Pitfalls to Avoid

• Delayed diagnosis: Failure to recognize symptoms early can lead to delayed treatment and poorer outcomes 1, 2
• Inadequate follow-up: Patients require regular laryngoscopic examinations to monitor recovery 1
• Overlooking delayed presentation: RLN palsy can present 2-3 days after surgery in rare cases 2
• Focusing only on voice symptoms: Dysphagia and aspiration risk should also be assessed and managed 1