Laryngeal nerve injury is a pathological condition characterized by dysfunction of this nerve, which leads to various disorders of the vocal and respiratory functions. The laryngeal nerve, being a branch of the vagus nerve, plays a key role in the innervation of the laryngeal muscles, responsible for the movement of the vocal cords, regulation of tone and coordination of breathing. The pathology can manifest itself as either unilateral or bilateral damage, with the latter being considered a more serious condition due to the high risk of developing acute respiratory failure. The clinical picture often includes hoarseness, difficulty breathing, coughing and a sensation of a foreign body in the throat. This condition requires a comprehensive approach to diagnosis and treatment, given the variety of possible causes of its occurrence.
History of the disease and interesting historical facts
The first descriptions of laryngeal nerve injuries appeared in the 19th century, when surgeons began to actively perform operations on the neck and chest. Of particular interest is the case described in 1875 by the German surgeon Theodor Billroth, who was the first to describe in detail the clinical manifestations after thyroid surgery. In the early 20th century, the development of laryngoscopy made it possible to study functional disorders of the vocal cords in more detail. According to the Mayo Clinic archives, the incidence of iatrogenic injuries has significantly decreased from 8% in the 1920s to today's 1-2%, indicating the evolution of surgical technology. Interestingly, during World War II, large-scale studies of traumatic injuries to the cervical spine were conducted, which significantly enriched the understanding of the pathophysiology of this condition.
Epidemiology (statistics of disease occurrence)
According to modern epidemiological studies, the incidence of laryngeal nerve injuries is approximately 1-2 cases per 1000 hospitalizations. Most often, this pathology is diagnosed in patients who have undergone thyroid surgery - about 3-5% of all cases. According to a meta-analysis published in the journal Thyroid in 2020, the risk of bilateral damage is 0.2%, while unilateral injuries are much more common - in 2.3% cases. The incidence shows a clear correlation with age, reaching a peak in the group of 45-65 years. Gender distribution shows a slight predominance among women (55%), which is associated with a higher prevalence of thyroid diseases in this population. It is important to note that about 20% cases develop due to non-surgical causes, such as inflammatory processes or injuries.
Genetic predisposition to the disease (involved genes and mutations)
Studies show that genetic predisposition plays a significant role in the risk of developing laryngeal nerve damage. Particular attention is paid to the genes responsible for the structure of connective tissue and the development of the nervous system. Polymorphisms in the COL1A1 and COL3A1 genes, encoding collagen types I and III, can affect the vulnerability of nerve structures during surgical interventions. In addition, mutations in the NGF and BDNF genes involved in neurotrophic support can reduce the ability of the nerve to regenerate after injury. A 2019 study by a group of scientists from Harvard University found a significant correlation between GDNF gene polymorphisms and the risk of developing neuropathy after thyroidectomy (OR = 2.3; p < 0.05). These data emphasize the importance of genetic screening before planning surgical interventions in the neck.
Risk factors for the development of this disease
The main risk factors include various physical and chemical influences:
- Surgeries, especially on the neck and upper chest
- Neck injuries including compression injuries
- Exposure to toxic substances, such as some chemotherapy drugs
- Radiation exposure in the neck area
- Infectious processes, in particular viral lesions
Prolonged mechanical stress, such as that caused by tracheostomy tubes or intubation, poses a particular risk. According to a study published in the journal Head & Neck, prolonged intubation for more than 48 hours increases the risk of injury by 3.6 times (CI 95%).
Diagnosis of this disease
The main symptoms are hoarseness, difficulty breathing, and dysphonia. Laboratory tests include:
- General blood test to rule out an inflammatory process
- Biochemical blood test
- Determination of thyroid hormone levels
Radiological methods:
- Ultrasound of the neck with Dopplerography
- MRI or CT of the cervical spine
- Laryngoscopy with video recording
Differential diagnosis is carried out with other causes of dysphonia, such as neuritis of other cranial nerves or organic lesions of the larynx.
Treatment
General treatment is aimed at eliminating the cause and preventing complications. Pharmacological therapy includes:
- Neurotrophic drugs
- Anti-inflammatory drugs
- Vitamin complexes of group B
Surgical intervention is indicated for:
- Persistent nerve compression
- Ineffectiveness of conservative treatment
- Severe functional impairments
Alternative methods include physical therapy, acupuncture, and biofeedback techniques.
List of drugs used to treat this disease
- Neuromidin (ipidacrine) - 20 mg 2-3 times a day
- Milgamma compositum - intramuscularly 2 ml daily
- Neuromultivit - 1 tablet 3 times a day
- Cortexin - lyophilisate for the preparation of a solution for intramuscular administration
- Cerebrolysin - 5-10 ml intravenously by drip
Disease monitoring
The effectiveness of treatment is monitored at regular intervals: initial examination after 1 month, then every 3 months during the first year. The main stages of monitoring include:
- Laryngoscopy
- Evaluation of voice function
- Respiratory function control
The prognosis depends on the extent of the damage and the timeliness of treatment. Possible complications include chronic dysphonia and recurrent laryngospasms.
Age-related features of the disease
In pediatric practice, the disease occurs with a more pronounced compensatory reaction of the body, but there is an increased risk of delayed speech development. In elderly patients, there is a slow regeneration of nerve fibers and a higher risk of complications. In the age group of 40-60 years, the most common iatrogenic etiology is associated with thyroid surgery.
Questions and Answers
- How long does it take to recover from laryngeal nerve injury? On average, the regeneration process takes from 6 to 12 months, but in case of severe damage, full recovery may not occur.
- Can nerve damage be prevented during surgery? Modern surgical technologies, including intraoperative nerve monitoring, reduce the risk to minimal values.
- What rehabilitation methods are the most effective? A comprehensive program that includes speech therapy and physical therapy shows the best results.
Advice from Dr. Oleg Korzhikov
Many patients often ask about the possibility of full voice restoration after damage. I would like to emphasize that with the right approach to rehabilitation, positive dynamics are observed in 85% cases. The question often arises about the need for additional examination if symptoms persist - I recommend repeating laryngoscopy 3 months after the primary injury. Regarding drug treatment, it is important to remember the need to strictly adhere to the prescribed dosages and courses of therapy.
