Background In modern thyroid surgery, while ensuring tumor eradication and surgical safety, more attention has been paid to the cosmetic effect and the functional protection of the anterior cervical region. Though sternocleidomastoid intermuscular approach (SMIA) thyroid surgery has emerged, it is less frequently applied in the clinic.

Objective To investigate the effect of SMIA thyroid surgery on unilateral thyroid carcinoma.

Methods A total of 144 patients with papillary thyroid cancer who received unilateral radical surgery for thyroid cancer in the Department of Thyroid (Hernia), Department of General Surgery, the First Medical Center of Chinese PLA General Hospital from November 2021 to April 2023 were selected, including 43 patients in the SMIA group. The linea alba cervicalis approach (LACA) was used in 101 patients. Two groups were matched with 38 patients in each group by scoring propensity matching method. Clinical data about 76 patients were retrospectively analyzed, and perioperative relevant indicators, postoperative complications, subjective sensation of incision and satisfaction were compared between the two groups.

Results  After matching, there were 14 males and 24 females in the SMIA group, aged 21-55 years, with an average age of (38.34 ± 9.20) years. There were 13 males and 25 females in the LACA group, aged 21-61 years, with an average age of (38.03 ± 10.41) years. The mean operation time of SMIA group was longer than that of LACA group (72.79 ± 7.08 min vs 67.29 ± 9.40 min, P=0.005). There were no significant differences in intraoperative blood loss, total drainage volume, average length of hospital stay, number of lymph node dissection and number of metastasis. No bleeding, incision infection, lymphatic leakage, permanent recurrent laryngeal nerve injury or permanent hypoparathyroidism occurred after surgery. There was 1 case of temporary recurrent laryngeal nerve injury in LACA group and 2 cases in SMIA group, temporary hypoparathyroidism occurred in 2 patients in LACA group and 3 patients in SMIA group, with no statistical difference (P > 0.05). There were no significant differences in the incidence of incision pain (5.3% vs 5.3%, P=1.000) and numbness (2.6% vs 7.9%, P=0.615), but there were significant differences in the incidence of neck tightness (7.9% vs 42.1%, P=0.001) and swallowing foreign body sensation (5.3% vs 36.8%, P=0.001). Postoperative incision satisfaction in SMIA group was significantly higher than that in LACA group (P<0.001).

Conclusion SMIA thyroid surgery is a perfect complement to traditional open and endoscopic thyroid surgery. It is safe and easy to carry out, and it can meet the cosmetic needs of patients, protect the anterior neck function, which is worthy of clinical promotion.