Multimodal ultrasonography for the prospective evaluation of soft-tissue changes after anterior cervical discectomy and fusion

BACKGROUND: While anterior cervical discectomy and fusion (ACDF) traditionally employs closed-suction drainage, a "no-drain" strategy is increasingly adopted despite concerns regarding hematoma and soft tissue swelling. This study utilized multimodal ultrasound to objectively evaluate postoperative recovery in non-drained ACDF patients. METHODS: In this prospective observational study, 47 patients undergoing ACDF without drainage were assessed on postoperative Day 1 and Day 7. High-frequency ultrasound (HFUS) measured residual fluid volume and tissue thickness (skin and sternocleidomastoid muscle), while shear wave elastography (SWE) quantified tissue stiffness. Comparisons were made between surgical and contralateral sides and across time points. RESULTS: Residual fluid volume significantly decreased from (34.71 ± 45.4) mL on day 1 to (6.68 ± 10.04) mL on day 7 (P = 0.003). Skin thickness was significantly greater on the surgical side compared to the contralateral side, whereas muscle thickness showed no significant bilateral differences. Skin elasticity values changed significantly over time, reflecting reduced stiffness during recovery, while muscle elasticity remained stable. No correlation was found between tissue thickness and elasticity. CONCLUSION: Multimodal ultrasound is helpful for assessment on postoperative residual fluid, soft tissue swelling, and muscle tension in patients without drainage tube placement after ACDF, supporting the safety of the "no-drain" strategy in carefully selected patients and providing objective biomarkers for optimizing perioperative management.