无充气经腋窝入路腔镜甲状腺手术因切口隐蔽、操作通道延展性好，已成为体现膜解剖理念和精准微创技术的重要术式。该术式以甲状腺系膜解剖为理论基础，强调术中实时辨认并拓展浅筋膜层、深筋膜层和内脏筋膜层之间的筋膜融合间隙。规范切口位置和体位摆放是降低并发症风险的前提，切口宜靠近腋窝顶部以减少瘢痕增生，上肢宜轻度上举屈肘，避免过度外展导致臂丛牵拉损伤。术中依次精准分离胸大肌肌膜表面间隙、剪开封套筋膜、穿越胸锁乳突肌间隙，并跨越颈鞘表面进入内脏筋膜层，可完成甲状腺及中央区淋巴脂肪组织的完整系膜切除。甲状腺位于内脏筋膜层内，其周围存在舌骨下肌筋膜后间隙、椎前筋膜前间隙、气管前间隙和环甲间隙等关键解剖平面。手术切除的实质，是对上述筋膜间隙的寻找、拓展与连通。该技术依赖术者对筋膜间隙的动态判断、器械协同配合及能量器械合理使用，有助于降低手术难度，提高操作安全性和效率。规范的筋膜融合间隙拓展策略可减少术中出血和相关并发症，促进甲状腺外科手术向标准化、高质量方向发展。

Gasless transaxillary endoscopic thyroid surgery, characterized by a concealed incision and an extensible operative channel, is an important procedure embodying the concepts of membrane anatomy and precision minimally invasive surgery. Based on mesothyroid anatomy, this procedure emphasizes real-time identification and expansion of the fascial fusion planes among the superficial, deep, and visceral fascial layers. Standardized incision selection and patient positioning are prerequisites for reducing complications: the incision is recommended near the axillary apex to minimize scar hypertrophy, and the upper limb should be mildly elevated with elbow flexion to avoid brachial plexus traction injury caused by excessive abduction. Intraoperatively, sequential and precise dissection of the plane on the surface of the pectoralis major fascia, incision of the investing fascia, passage through the sternocleidomastoid interval, and extension across the carotid sheath to the visceral fascial layer allow complete mesothyroid dissection of the thyroid gland and central compartment lymphofatty tissue. The thyroid gland lies within the visceral fascial layer and is surrounded by key anatomical planes, including the retro-infrahyoid muscle fascial space, prevertebral fascial space, pretracheal space, and cricothyroid space. The essence of resection is the identification, expansion, and connection of these fascial planes. This technique depends on dynamic judgment of fascial spaces, coordinated instrument manipulation, and rational use of energy devices, thereby helping reduce operative difficulty and improve safety and efficiency. A standardized strategy for expanding fascial fusion planes may decrease intraoperative bleeding and related complications and promote standardized, high-quality development of thyroid surgery.