We retrospectively analyzed the clinical data of 99 patients who underwent surgical treatment for unilateral papillary thyroid cancer admitted to our hospital between January 2021 and December 2022. This project was approved by the ethics committee of Wanbei Coal and Electricity Group General Hospital (No. WBZY-LLWYH-2024-019). We certify that the study was performed in accordance with the 1964 declaration of HELSINKI and later amendments. All procedures in this study were conducted in accordance with the Ethics Committee of Wanbei Coal and Electricity Group General Hospital. All patients were informed of the purpose, modality, precautions, and possible complications before enrollment and written informed consent was obtained from all the participants prior to the enrollment of this study.

①All patients had a unilateral solitary thyroid mass, were initially considered to have thyroid cancer by preoperative ultrasound or fine needle aspiration biopsy (FNAB) and were confirmed to have PTC by routine postoperative pathology.

②Thyroid lesions with a tumor diameter ≤ 2 cm.

③No invasion of the thyroid peritoneum, trachea, esophagus, superior laryngeal nerve or laryngeal recurrent nerve (the patient had no hoarseness and normal vocal cord movement on laryngoscopy, no choking or coughing from drinking and no weakness of pronunciation). Moreover, the patients were free of lateral neck or distant metastasis.

④The patient had high cosmetic requirements, requested relevant surgical treatment after doctor‒patient communication and signed the informed consent form.

①Patients who were in poor general condition or had other underlying conditions and who could not tolerate surgical procedures.

②Patients with a history of previous neck and affected chest wall surgery or radiotherapy.

③ Patients who were considered to have bilateral or unilateral thyroid cancer with lateral neck lymph node metastasis.

④Tumors larger than 2 cm or tumors with invasion into other organs immediately above the upper pole into the larynx.

If the patient refused treatment, was lost to follow-up or had other diseases, the patient was automatically excluded from the group. Finally, the patients in the control group were subjected to COACAS. A total of 36 patients were enrolled. Patients in the experimental group underwent TAWISES. A total of 36 patients were enrolled.

The general and clinical data (operative time, hospitalization time, 24-h postoperative pain index, tumor size, clinical cost, etc.) of the two groups were compared and analyzed; postoperative satisfaction; discomfort, such as neck pain and numbness; postoperative disease status; and the impact of scar contracture on daily life were investigated. All patients were followed up for 1 year.

We investigated the acceptability of the surgery in terms of cosmetic results, surgical safety, neck discomfort, total hospitalization costs, and acceptance of TAWISES versus COACAS in our region by analyzing 300 patients who visited our department for thyroid disease.

To reduce bias, the surgeries on patients in both the experimental and control groups were performed by the same group of (primary and one assistant) surgeons. The data were collected, evaluated, and registered by the same 2 persons during and after the operation. In case of differences, the senior physician evaluated and confirmed the data.

After successful general anesthesia, the patient was placed in a supine position with a pillow under the shoulder, and the head was slightly tilted to the healthy side. The upper arm on the affected side was fully abducted to expose the axilla. An approximately 3–5 cm long incision was made in the skin (the window of endoscope and forceps), and the skin was separated along the surface of the pectoral muscle under direct vision. Then, a 5 mm incision was made ventral to the incision about the anterior axillary line to implant a 5 mm trocar (an ultrasonic knife implantation window). The sternocleidomastoid muscle was exposed with the aid of a retractor. The cavity was entered through the gap between the sternal and clavicular heads of the sternocleidomastoid muscle. The scaphoid hyoid muscle was explored and further separated. The anterior cervical strap muscle was pulled up with a noninflated transaxillary retractor. The thyroid gland was fully exposed, and the true and false envelopes were separated. The recurrent laryngeal nerve was found and exposed. Then, the superior-middle-inferior pole of the thyroid gland was disconnected by ultrasonic knife electrocoagulation. The superior parathyroid gland and blood supply were preserved in situ as much as possible. The lymph nodes in the VI area were cleared along the recurrent laryngeal nerve after routine intraoperative freezing examination revealed PTC. We focused on preserving the inferior parathyroid gland and its blood supply. The trauma surface was definitively hemostatic, and the surgical cavity was rinsed with sterile water. The instruments were inventoried, and a drainage tube was placed after the operation. (As shown in Fig. 1)

Transaxillary approach inflation-free single-port lumpectomy for radical thyroid cancer

After satisfactory anesthesia, the patient was placed in a supine position with the back of the shoulder padded and the head slightly tilted back to expose the neck. A transverse incision approximately 5 cm in length was made on the sternum. The skin and the subcutaneous and broad neck muscles were cut, and the flap was dissociated. The midline was incised, and the affected anterior cervical strap muscle was freed to reveal the affected thyroid gland. The affected laryngeal nerve was free and exposed. The upper, middle and upper pole vessels of the affected thyroid gland were dissociated and ligated, and the affected thyroid gland was excised. The lymph nodes in the VI area were removed for routine pathology after routine freezing confirmed PTC. After the operation, a pressure drainage tube was placed in the thyroid fossa on the affected side (as shown in Fig. 2).

Traditional open surgery through the anterior neck for radical thyroid cancer

The following parameters were observed: (1) the operative time, which was defined as the time from skin incision to suture completion; (2) intraoperative bleeding; (3) postoperative complications (postoperative bleeding, infection, nerve injury, etc.) and the postoperative pain index at 24 h (VAS score: 0, no pain; 1–3, mild pain; 4–6, moderate pain; and 7–10, severe pain); (4) drainage tube carrying time (experimental group drainage fluid ≤ 20 ml, control group drainage fluid ≤ 10 ml, drainage tube was removed); (5) total hospitalization and total cost to patients; (6) neck discomfort for 3, 6 and 12 months after surgery; (7) recurrence and metastasis status of patients in both groups after one year; and (8) patient satisfaction and the impact of the two surgical procedures on patients’ daily social life. Satisfaction was rated based on the Numerical Rating Scale (NRS). NRS was used to evaluate the patients’ satisfaction level. The satisfaction level was rated from 1 to 7. A higher score indicated higher patient satisfaction. The efficacy and treatment cost acceptability of radical thyroidectomy were assessed.

SPSS 26 statistical software was used for data analysis. The measurement data are expressed as the mean ± standard deviation (x ± s), and a t test was used to compare normally distributed data; a nonparametric test was used to compare nonnormally distributed data, and the X2 test was used to compare discrete data, such as the number of patients (n) and rate (%); P < 0.05 indicated a statistically significant difference. Missing values were processed using mean padding; outliers were detected using standard deviation methods for identification and processing.