What are the guidelines for reducing recurrent laryngeal nerve (RLN) injury during thyroidectomy in the absence of a nerve stimulator?

Guidelines for Reducing RLN Injury Without Nerve Stimulator During Thyroidectomy

Complete visual identification and dissection of the recurrent laryngeal nerve from thoracic inlet to larynx is the gold standard for preventing RLN injury during thyroidectomy, and this technique alone—without nerve monitoring—remains the cornerstone of safe thyroid surgery. 1

Core Surgical Technique Requirements

Visual identification must be routine and systematic in every thyroidectomy, as this represents the most critical evidence-based method for reducing nerve injury. 1 The International Journal of Surgery emphasizes that routine recurrent nerve visualization and dissection is the surgical cornerstone, with strong evidence supporting this approach even without intraoperative nerve monitoring (IONM). 1

Specific Technical Principles

Avoid blind ligatures or coagulation at all costs, particularly in the tracheoesophageal groove where the RLN courses. 1 This single principle prevents the majority of inadvertent injuries.

Identify the nerve using one of four anatomical approaches based on surgical context: 2

• Lateral approach (most common in primary surgery): Dissect around the inferior thyroid artery at mid-thyroid level 2
• Inferior approach: Locate the nerve at its entry into the neck, particularly useful in revision surgery where scar-free tissue exists 2
• Superior approach: For large or substernal goiters, release the upper pole first, then identify the nerve at its laryngeal entry point under the cricopharyngeus muscle 2
• Medial approach: For substernal/retropharyngeal goiters, divide the isthmus first and dissect laterally from the trachea 2

High-Risk Anatomical Zones Requiring Extra Caution

The area near Berry's ligament and the tubercle of Zuckerkandl represents the most dangerous zone, where most RLN lesions occur within a short 2 cm tract. 1 During dissection of this region, tenacious adherences between the glandular capsule and nerve branches create the highest injury risk. 1

Anticipate anatomical variations including: 1

• Nerve distortion by voluminous or retrosternal goiter
• Precocious division of extralaryngeal branches
• Non-recurrent laryngeal nerve (occurs in 1.14% of cases) 3
• Intertwining between neural and arterial branches

Critical Traction Management

Use intermittent tension rather than continuous traction during dissection. 1 Continuous traction is the main cause of RLN injury, even when the nerve appears visually intact. 1 Alternate between dissecting the upper and inferior poles to avoid sustained stretch on the nerve. 1

Avoid excessive medial rotation of the thyroid gland, as this maneuver causes stretch injury to the distal RLN segment adherent to Berry's ligament. 1

Specific High-Risk Scenarios

Consider near-total lobectomy in cases of difficult surgical conditions with severe anatomical distortion, though evidence for this reducing neural damage is not strong. 1

Reserve prophylactic or therapeutic neck dissection for referral centers, as these procedures are associated with higher incidence of both transient and permanent RLN injuries. 1, 4

Documentation and Medicolegal Protection

Document RLN identification and integrity in the surgical report with sufficient detail demonstrating that standard of care was met. 1 In 80% of malpractice claims, patients won due to inadequate surgical notes or inability to demonstrate meticulous technique. 1

Perform preoperative flexible laryngoscopy on all patients to identify any pre-existing vocal fold alterations. 1 This baseline assessment is critical for medicolegal purposes and clinical management.

Obtain detailed informed consent explicitly discussing RLN injury risk, and ensure the patient understands this is a known complication even with perfect technique. 1

Postoperative Management

Perform immediate postoperative laryngoscopy in any patient with suspected laryngeal malfunction to obtain early diagnosis of vocal cord palsy. 1

Establish multidisciplinary care including otolaryngology and speech therapy for any patient with confirmed RLN injury. 1

Common Pitfalls to Avoid

Do not assume visual nerve integrity equals functional integrity—most injuries occur to visually intact nerves rather than transected ones. 1 Mechanisms include inadvertent clamping during inferior thyroid artery ligation, especially with nerve bifurcation near Berry's ligament. 1

Do not place ligature knots too close to the nerve, as constricting bands of connective tissue can cause delayed injury. 1

Recognize that surgeon visual assessment is poor—only 10-14% of injured nerves are identified intraoperatively by visual inspection alone, and only 16% of bilateral nerve injuries are suspected during surgery. 1

Evidence on Nerve Monitoring

While nerve monitoring is not required, the American Academy of Otolaryngology-Head and Neck Surgery states it is reasonable to consider IONM, particularly for: 1

• Bilateral thyroid surgery (to prevent bilateral vocal fold paralysis)
• Revision thyroid surgery
• Surgery with existing RLN paralysis

However, systematic reviews have failed to demonstrate statistically significant differences between visualization alone versus visualization plus IONM for preventing injury. 1 IONM is not considered "standard of care" in U.S. legal proceedings. 1