Novel evaluation of the sternocleidomastoid muscle of head and neck cancer patients using shear wave elastography: A preliminary exploratory pilot study

Aim: Shear wave elastography is commonly used to evaluate muscle stiffness and thickness. This study aimed to evaluate the stiffness and thickness of the sternocleidomastoid muscle in patients diagnosed with head and neck cancer undergoing neck dissection (removal of lymph nodes). Materials and methods: Ten subjects with head and neck cancer were recruited. Two radiographers performed ultrasound and shear wave elastography scans to evaluate muscle stiffness and thickness in the sternocleidomastoid muscle pre-surgery, at 6 weeks, and at 6 months post-surgery. Results: The cohort had a mean age of 56.8 (±8.22) years, with equal numbers of males and females. Half had unilateral surgery (four left and one right), while the other half had bilateral surgery. One patient had the entire sternocleidomastoid muscle resected (participant HN2). Comparing all time points from pre-surgery to 6 weeks and 6 months, there was no significant change in sternocleidomastoid muscle thickness (pre-surgery to 6 weeks: 0.11 ± 2.45 cm; t = 0.18, p = 0.86; pre-surgery to 6 months: 0.36 ± 2.08 cm; t = −0.64, p = 0.53; 6 weeks to 6 months: 0.47 ± 1.53 cm; t = −1.15, p = 0.26). From pre-surgery to 6 weeks and 6 months, there was no statistically significant change in shear wave elastography readings (pre-surgery to 6 weeks: 3.62 ± 7.45 kPa; t = −1.82, p = 0.08; pre-surgery to 6 months: 3.33 ± 11.2 kPa; t = 1.11, p = 0.28). However, from 6 weeks to 6 months, the shear wave elastography values increased significantly by 6.95 ± 6.48 kPa ( t = 4.01, p < 0.001). Conclusion: This preliminary exploratory study demonstrates the feasibility of longitudinal shear wave elastography assessment in this cohort and identifies an increase in sternocleidomastoid muscle stiffness between 6 weeks and 6 months, which warrants further investigation in larger, stratified studies with functional correlation.