Risk factors postoperative diaphragmatic dysfunction in video-assisted thoracic surgery patients: a dynamic digital radiography study.

BACKGROUND

Postoperative diaphragmatic dysfunction (DD) is a frequent complication following thoracic surgery, which can significantly impair respiratory function, prolong recovery, and increase morbidity. Video-assisted thoracic surgery (VATS), a minimally invasive surgical approach, has gained widespread use due to its advantages over traditional open thoracotomy, including smaller incisions, reduced postoperative pain, and faster recovery times. However, despite these benefits, DD remains a notable concern in VATS patients, potentially due to surgical manipulation of the diaphragm and surrounding structures. Dynamic digital radiography (DDR) offers a promising tool for the quantitative assessment of diaphragmatic excursion. Nevertheless, the factors associated with DD as assessed by DDR in VATS patients, and the potential value of DDR in identifying patients at risk, remain underexplored. This study aims to identify factors associated with postoperative DD using DDR in patients undergoing VATS.

METHODS

Patients undergoing thoracic surgery at The First Affiliated Hospital of Guangzhou Medical University in Guangzhou, China, between January 2025 and September 2025, were retrospectively included. DD was defined as maximal diaphragmatic excursion during forced respiration ≤26.03 mm (left) or ≤21.22 mm (right), based on the 95% lower limit of normal reference values in healthy Asian volunteers. Demographic, clinical, surgical, pulmonary function, and imaging variables were collected. Univariate analyses were performed to screen candidate variables (P<0.1), followed by multivariate logistic regression to identify independent risk factors.

RESULTS

A total of 190 patients were included, of whom 121 (63.68%) developed DD. Multivariate analysis identified several independent risk factors for postoperative DD in VATS patients. Length of stay (LOS) was positively associated with DD [odds ratio (OR) =1.466, 95% confidence interval (CI): 1.097-1.958, P=0.01]. Left diaphragmatic motion amplitude during quiet breathing (LDA-QB) <10.3 mm and right diaphragmatic motion amplitude during quiet breathing (RDA-QB) <7.0 mm were also significant predictors, with ORs of 19.275 (95% CI: 2.037-182.429, P=0.01) and 21.658 (95% CI: 2.892-162.193, P=0.003), respectively. Higher LDA-QB was associated with increased risk (OR =1.111, 95% CI: 1.009-1.223, P=0.03). In contrast, higher left diaphragmatic motion amplitude during forced breathing (LDA-FB) and right diaphragmatic motion amplitude during forced breathing (RDA-FB) reduced the risk of DD (OR =0.777, 95% CI: 0.827-0.927, P<0.001; OR =0.875, 95% CI: 0.872-0.927, P<0.001).

CONCLUSIONS

Reduced diaphragmatic excursion measured by DDR was found to be independently associated with postoperative DD. Even in patients without established DD, reduced excursion may be associated with clinical outcomes, and early identification of such patients could facilitate targeted respiratory rehabilitation, potentially optimizing recovery and reducing postoperative respiratory complications. However, given the observational nature of this study, these findings require confirmation in prospective cohorts.