Intraoperative Management of Unexpected Doornail Hilar Lymph Nodes During Robot- Assisted Pulmonary Resection: Surgical Experience and Associated Preoperative Factors

<title>Abstract</title> <p>Background: Hilar lymph nodes with dense adhesion to the bronchus and pulmonary artery (“doornail” nodes) can be encountered unexpectedly during robot-assisted pulmonary resection. We report our experience managing these nodes and associated factors. Methods: This retrospective single-center cohort study included 1,185 patients undergoing robot-assisted pulmonary resection (March 2021–September 2024). Preoperative factors were analyzed using Firth penalized logistic regression in a clinically selected model (age, maximal voluntary ventilation [MVV], and tumor diameter). Operative time and blood loss were compared using robust regression models. Perioperative outcomes were compared descriptively between forced dissection and en bloc stapling. Results: Doornail hilar lymph nodes occurred in 48 of 1,185 patients (4.05%; 95% CI, 3.07–5.33%). Older age remained associated with this finding after adjusting for MVV and tumor diameter (adjusted OR per 10 years, 2.316; 95% CI, 1.533–3.596; P&lt;0.001). Operative time was longer unadjusted (105 vs 92 min; P=0.027) but not after adjustment. Among these 48 patients, 45 (93.8%) received en bloc stapling with no blood loss exceeding 200 mL, transfusion, or prespecified in-hospital complication, whereas all 3 (6.3%) who underwent forced dissection had substantial bleeding (700–2,400 mL), and 2 required transfusion. No conversion to thoracotomy occurred in either group. Conclusions: Doornail hilar lymph nodes occurred in about 4% of patients; older age remained associated with this finding after adjusting for MVV and tumor diameter. Because strategy selection was non-random and groups differed in resection extent, comparative safety cannot be established; en bloc stapling after tissue thinning is feasible when a node cannot be safely separated.</p>