599. ASSESSMENT OF BREATHING MECHANICS IN OESOPHAGEAL CANCER SURVIVORS USING A 3D-MOTION CAPTURE SYSTEM

Abstract Background Traditional open surgery is characterised by an intercostal incision. The associated ribcage injury may precipitate the development of post-thoracotomy-related pain, with impaired respiratory muscle contraction, leading to compromised coughing and decreased lung volumes. These changes in breathing mechanics may precipitate pulmonary complications, occurring in up to 40% of the patients. There is however no data available on the long-term breathing function and its implications on the health-related quality of life following oesophagectomy. This proof-of-concept study aimed to objectively measure breathing movements using a 3D-motion capture system and to understand the impact of surgery on breathing patterns in oesophageal cancer survivors. Methods Oesophageal cancer survivors who were disease-free for at least 1 year postoperatively and healthy controls were included. Participants completed quality-of-life (QoL) questionnaires, including EORTC QLQ-C30, -OG25 and LASORS. Eighty-nine retroreflective markers were affixed to the participants' trunks to measure respiratory movements via the Vicon motion capture system during handheld spirometry performance. The highest spirometry value was recorded for the slow inspiratory (SIVC) and forced expiratory vital capacity (FEVC). Concurrent movement data was obtained from adjacent surface markers connected to the midpoint, allowing evaluation of the total volumetric movement of the trunk, and thoracic and abdominal contributions. Results Eighteen patients (median age 68) and 22 controls (median age 29) were included. Patients exhibited a significantly reduced SIVC alongside decreased chest movement contribution (median 2.4519 litres IQR 0.9270) compared to controls (median 3.1492 litres, IQR 1.8381) (p=0.013). Meanwhile, patients also had significantly lower FEVC with lower abdominal movement (median 1.5134 litres, IQR 0.7852) compared to controls (median 2.1263 litres, IQR 0.8740) (p=0.039). The QoL amongst patients was significantly worse for half of the EORTC domains, including physical functioning, fatigue, dyspnoea, pain and discomfort, and coughing (p<0.05). Additionally, the QoL of patients was consistently lower across all LASOR domains (p<0.05). Conclusion Current data showed lower spirometry parameters and breathing movements amongst oesophageal cancer survivors, suggestive of impaired breathing mechanics. Specifically, chest expansion was compromised during slow inhalation, while abdominal contraction was reduced during forced exhalation. These findings suggest restrictive changes in breathing mechanics