Hydrodissection Tunneling Technique on Recurrent Laryngeal Nerve Protection During Thyroidectomy

Summary

Protection of the recurrent laryngeal nerve (RLN) is a key focus and difficulty in thyroid surgery. Unilateral RLN injury can lead to ipsilateral vocal cord paralysis, resulting in hoarseness in patients postoperatively. Bilateral RLN injury, however, may cause bilateral vocal cord paralysis, leading to dyspnea and even asphyxiation; in severe cases, tracheotomy and permanent tracheal cannulation are required. Consequently, RLN injury significantly impacts patients' postoperative quality of life and career development. Guidelines and consensuses both domestically and internationally recommend that during the management of the posterior thyroid capsule, active detection, exposure, and dissection of the RLN, combined with meticulous capsular dissection along the RLN, should be performed to effectively reduce the incidence of RLN injury. While active anatomical identification of the RLN can clarify the nerve branches and their relationship with surrounding tissues, facilitating surgical procedures such as ligation and hemostasis, the traditional method of dissecting with instruments like hemostats or right-angle forceps (either blunt or sharp dissection along the nerve surface) increases the risk of nerve injury due to traction, clamping, or thermal damage. This is particularly challenging for less experienced surgeons, who face great difficulties in using energy devices near the RLN without causing injury-a major concern in the field of thyroid surgery.

Diluted epinephrine solution exhibits excellent hemostatic effects in local surgery, improves surgical field clarity, and shortens operation time. Its safety has been clinically verified, and it is commonly used in plastic and cosmetic surgery, joint surgery, and the cavity creation process of endoscopic thyroid surgery. Based on this, this study innovatively proposes the "Huaxi Tunnel Technique": on the basis of meticulous posterior capsular dissection in traditional thyroid surgery, the RLN detection point on the posterior capsule below the lower pole of the thyroid is located using the "cross method" and exposed. A syringe containing diluted epinephrine solution is then used, with its front hose inserted along the RLN towards the laryngeal entry direction. Rapid injection is performed, and the pressure generated by this injection separates the fibrous connective tissue on the RLN surface, forming a "tunnel" from the RLN detection point to the laryngeal entry site-thus achieving exposure and dissection of the RLN.

This technique offers multiple advantages: epinephrine reduces local bleeding, enhancing surgical safety and the convenience of meticulous capsular dissection; tunnel formation causes edema and discoloration of the fibrous connective tissue in the posterior thyroid capsule (while the parathyroid glands remain uncolored), facilitating the rapid identification and protection of the parathyroid glands. Preliminary preclinical experiments have confirmed that the technique reduces the difficulty of RLN exposure and dissection, decreases intraoperative bleeding and complication rates, and improves the safety of thyroid surgery. To further evaluate the efficacy, safety, and operability of this tunnel technique for RLN exposure and dissection, a prospective single-blind randomized controlled trial comparing it with traditional thyroid surgery methods is hereby conducted.

Conditions

• Patients Undergoing Open Thyroid Surgery

Interventions

PROCEDURE

Hydrodissection tunneling technique

A 5-ml syringe was loaded with adrenaline solution diluted in normal saline (1 mg adrenaline in 250 ml saline, concentration 4 µg/ml) and fitted with a 2-3 cm soft extension tube as the injection tip. After the recurrent laryngeal nerve (RLN) was identified by the cross-hatch method at the posteroinferior capsule below the lower pole of the thyroid gland, the solution was rapidly injected along the RLN's course toward its laryngeal entry point. The hydraulic pressure created by this rapid injection separated the fibrous connective tissue surrounding the nerve, forming a tissue tunnel from the initial identification site to the laryngeal entry point. Subsequent nerve dissection was then performed within this tunnel.

Sponsors & Collaborators

• West China Tianfu Hospital

  collaborator OTHER

• Shang Jin Hospital of West China Hospital,Sichuan University

  collaborator UNKNOWN

• Sun Yat-Sen University Cancer Center

  collaborator OTHER

• Sichuan Provincial People's Hospital

  collaborator OTHER

• Sanya People's Hospital

  collaborator UNKNOWN

• West China Hospital

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-03-01

Primary Completion

2026-01-01

Completion

2026-03-01

Countries

• China

Study Locations