Secondary lower extremity lymphoedema is a chronic progressive condition that frequently develops after cancer treatment and results in persistent swelling, recurrent cellulitis and impaired quality of life. Lymphaticovenous anastomosis (LVA) is an established physiological microsurgical treatment; however, postoperative outcomes vary and evidence-based adjunctive postoperative management remains limited. A novel pneumatic lymphatic drainage (PLD) system has been developed to deliver anatomically directed, pathway-aligned mechanical stimulation that mimics manual lymphatic drainage. Its clinical efficacy following LVA has not yet been evaluated in a randomised controlled trial.

This multicentre, open-label, parallel-group randomised controlled trial will enrol adults (≥18 years) with unilateral secondary lower extremity lymphoedema (International Society of Lymphology stage I–II) undergoing LVA. Participants will be randomised 1:1 to receive PLD plus standard postoperative care or standard postoperative care alone. PLD will be initiated on the day of surgery and continue for 6 months (Day 183). The primary outcome is the rate of improvement in excess limb volume (EV) at Day 183 relative to baseline, calculated from circumferential measurements taken at 4 cm intervals using the truncated cone method, with the contralateral limb serving as an internal control. Secondary outcomes include longitudinal trajectories of EV, improvement in excess limb fluid volume assessed by bioimpedance, the Lymphedema Quality of Life Questionnaire, cellulitis incidence and safety outcomes. A total of 64 participants (32 per group) will provide 80% power (two-sided α=0.05) to detect a 15-percentage-point between-group difference in the rate of improvement in EV at 6 months, assuming a common SD of 20 percentage points and allowing for attrition. Primary analyses will follow the ITT principle using mixed-effects models for repeated measures.

The study was approved by the Chiba University Certified Review Board (approval number: CRB0119-25; approval date: 15 December 2025) and was conducted in accordance with the Declaration of Helsinki and the Japanese Clinical Trials Act. Results will be disseminated through peer-reviewed publications and presentations at national and international scientific conferences, irrespective of study outcomes.

jRCTs032250600.