From the Guidelines
The spontaneous return of function in the recurrent laryngeal nerve (RLN) after injury is estimated to occur in approximately 30-60% of cases, depending on the type and severity of injury, as supported by clinical practice guidelines 1. When considering the management of RLN injury, it is crucial to assess the cause of dysphonia and design treatment options to establish prognosis, as significant breathiness suggestive of vocal fold paralysis should lead to earlier laryngoscopy than minor roughness, which could potentially be observed for some time 1. Key factors influencing the likelihood of spontaneous recovery include:
- Type of injury, with neuropraxia having the highest rates of spontaneous recovery, often approaching 60-70%, typically within 6-12 months after injury
- Severity of injury, with more severe injuries like axonotmesis having lower spontaneous recovery rates of 30-50% and may take 6-18 months for maximal improvement
- Patient age, mechanism of injury, length of damaged segment, and time elapsed since injury, all of which can impact the potential for spontaneous recovery While waiting for potential spontaneous recovery, patients should receive voice therapy to prevent compensatory behaviors that might hinder recovery, and regular laryngoscopic examinations every 1-3 months to monitor vocal fold mobility, as early evaluation, identification, and institution of surgical and nonsurgical treatment of vocal fold paralysis can have a notable impact on ultimate vocal function 1.
From the Research
Recurrent Laryngeal Nerve Recovery
- The percentage of spontaneous return of the recurrent laryngeal nerve (RLN) is not directly stated in the provided studies, but the recovery patterns and outcomes are discussed in various contexts.
- A study on canine laryngeal nerve injury models found that the injured RLN has a strong tendency to recover, with restoration of adductor strength related to the severity of RLN injury 2.
- Another study using a computer simulation of RLN recovery found that more severe injuries were associated with greater degrees of synkinesis, but the simulation did not provide a specific percentage of spontaneous return 3.
- A clinical study on RLN liberations and reconstructions reported that patients with RLN paresis/paralysis can experience significant improvement in phonation, even complete voice recovery, after nerve liberation or reconstruction 4.
- A study on serial electromyography after acute RLN injury found that LEMG results earlier than 3 months may overestimate a negative prognosis, and that recovery patterns can be assessed using serial electromyography 5.
- A study on RLN injury after esophagectomy for esophageal cancer reported that almost half of the patients with RLNP recovered fully after more than 6 months of follow-up, with a median follow-up of 17.5 months 6.
Recovery Outcomes
- The studies suggest that the recovery of the RLN can vary depending on the severity of the injury, the type of treatment, and the individual patient's response to treatment.
- The outcomes of RLN recovery can include complete voice recovery, improved phonation, and residual symptoms, with some patients requiring surgical intervention 4, 6.
- The timing of recovery is also an important factor, with some studies suggesting that early assessment of RLN recovery may not accurately predict long-term outcomes 5, 6.