Role of the sternocleidomastoid muscle flap in modified radical neck dissection: A retrospective single-institution series of 32 patients

Background/objective: The sternocleidomastoid (SCM) muscle flap technique was incorporated into modified radical neck dissection (MRND-SCM flap) to reduce traction injury to the spinal accessory nerve (SAN), improve surgical visualization, protect the carotid artery, and maintain postoperative neck contour. This study aimed to evaluate the feasibility and safety of this approach in patients with N2–N3 head and neck cancer. Methods: Thirty-two patients with clinically N2–N3 head and neck cancer underwent MRND-SCM flap at a single tertiary institution between May 2017 and December 2022 (34 total procedures). Surgical outcomes, perioperative complications, and active shoulder range of motion (ROM) — measured using a standard goniometer preoperatively and at 1, 3, and 6 months postoperatively — were analyzed. Results: The operative procedure was successfully completed in all 32 patients. One patient had SCM muscle partial necrosis during the early postoperative period due to wound infection. Neck tightness developed in 5 patients (15.6%). No SCM rupture, severe atrophy, or clavicle fracture occurred. One patient developed a postoperative hematoma requiring reoperation. Shoulder abduction and flexion decreased significantly at 1 and 3 months but recovered to near-baseline by 6 months. External rotation recovered by 3 months. One patient (3.1%) showed shoulder droop on clinical inspection. Conclusions: MRND-SCM flap demonstrates favorable feasibility and safety profiles in this single-institution retrospective series. The technique preserves the SCM muscle, maintains postoperative neck contour, enables en bloc lymph node dissection, and is associated with near-complete shoulder ROM recovery by six months. These findings represent preliminary safety and feasibility signals. Prospective multicenter studies with larger cohorts are warranted to validate these results.