Study on the Efficacy of Laparoscopic-Assisted Thyroglossal Duct Cyst Resection Via Submental Approach

1. Project-defined project goals and task requirements analysis 1.1 Project Goals 1.1.1 Overall Goal This project aims to conduct a prospective randomized controlled study to scientifically evaluate the clinical efficacy and safety of endoscopic-assisted thyroglossal duct cyst resection through an un-inflated submental approach, establish a standardized surgical procedure, and provide evidence-based medical evidence for the promotion of minimally invasive surgery with no neck scars.

1.1.2 Specific Goals 1.1.2.1 Efficacy Verification Goal Compare the differences in surgical time, intraoperative blood loss, hospital stay, and postoperative pain between the submental approach endoscopic surgery and the traditional Sistrunk surgery.

1.1.2.2 Safety Assessment Goal Monitor the incidence of complications and the 1-year recurrence rate of the two groups, ensuring that the recurrence rate of the observation group is controlled within 5% .

1.1.2.3 Aesthetic Effect Evaluation Goal Use the Vancouver Scar Scale (VSS) to evaluate the aesthetic appearance of the incision at 1, 3, and 6 months after surgery.

1.1.2.4 Technical Standardization Goal Summarize the key technical points and form a standardized surgical operation procedure.

1.2. Task Requirements Analysis 1.2.1 Clinical Requirements Thyroglossal duct cysts account for 75% of the spectrum of congenital diseases in the neck. Although the traditional Sistrunk surgery reduces the recurrence rate to below 5%, it leaves scars on the neck, causing psychological burden to patients. Therefore, a treatment plan that balances cure and aesthetics urgently needs to be established.

1.2.2 Technical Requirements The existing endoscopic approaches through the mouth, chest, and breast have high infection risks, large trauma range, and require inflation. The un-inflated submental approach utilizes the natural skin creases under the chin, has a short path, can directly handle the hyoid bone, and combines aesthetics with safety. However, it lacks large-sample randomized controlled studies for verification.

1.2.3 Evidence-Based Requirements Most existing studies are small-sample case reports and lack high-quality controlled studies [2]. Conducting rigorous randomized controlled trials to systematically compare the efficacy, safety, and aesthetic effects of the two surgical methods is an urgent need to promote clinical application.

1.2.4 Social Benefit Requirements Neck scars affect patients' self-confidence and quality of life. Achieving no-neck scars is an embodiment of the medical model's shift towards "physical and mental rehabilitation", with good social benefits and promotion prospects.

2 Project Objectives and Main Technical Difficulties and Issues in Task Resolution 2.1 Technical Difficulties in Laryngeal Bone Handling under Endoscopy 2.1.1 Description of the Difficulties The recurrence rate can be as high as 50% if the laryngeal bone is not handled thoroughly. Under the endoscopic view, the laryngeal bone is located deep within and has a hard texture. The primary difficulty is to precisely disarticulate it while avoiding damage to the hypoglossal nerve and the superior laryngeal nerve.

2.1.2 Solution Ideas Preoperative CT three-dimensional reconstruction is used to predict the resection range; during the operation, an ultrasonic bone knife is used for precise disarticulation; the "five-step method" is adopted as the standard operating procedure; intraoperative nerve monitoring is used to assist in protecting the nerves.

2.2 Narrow Operating Space and Difficulties in Field Exposure 2.2.1 Description of the Difficulties There are no natural cavities in the neck, and the small incision under the chin placed with the endoscope leads to the "chopstick effect". The cyst is located below the laryngeal bone, and the field exposure is difficult.

2.2.2 Solution Ideas The non-inflated suspension method is used to establish the operating space; specialized and elongated endoscopic instruments are modified; the suspension tension is dynamically adjusted; the indications are strictly selected, excluding cases with a diameter > 4 cm or those in the infectious stage.

2.3 Identification and Protection of Important Nerves and Blood Vessels 2.3.1 Description of the Difficulties The submandibular area involves the hypoglossal nerve, superior laryngeal nerve, etc. The identification is difficult under the two-dimensional endoscopic view, and incorrect injury can lead to serious complications.

2.3.2 Solution Ideas The nerve is located by using the digastric muscle and masseter muscle as references ; the surgical field is kept blood-free; postoperative close observation of swallowing and speech functions is conducted.

2.4 Learning Curve and Standardization of Surgical Procedure 2.4.1 Description of the Difficulties The surgeon needs to have both open surgery experience and endoscopic skills. The initial operation time is longer (median 135 minutes), and there is a possibility of conversion to open surgery.

2.4.2 Solution Ideas Conduct anatomical training and simulation operations; formulate standardized surgical procedures; initially operated by experienced physicians; regularly analyze and summarize to continuously optimize.

2.5 Objective Evaluation of Aesthetic Effect 2.5.1 Description of the Difficulties Scar evaluation is subjective. How to objectively quantify the aesthetic effect is a research design difficulty.

2.5.2 Solution Ideas The Vancouver Scar Scale (VSS) is used to score from four dimensions: color, thickness, vascular distribution, and softness; combined with patient satisfaction VAS evaluation; third-party blind assessment is conducted.