Determination of the Optimal Landmark for Tube Thoracostomy in Trauma Patients: A Retrospective Study

<b>Background/Objectives</b>: Accurate and prompt tube thoracostomy (TT) placement within the safety zone while avoiding diaphragmatic injury remains challenging, particularly in trauma patients with distorted thoracic anatomy. This study evaluated the accuracy and safety of landmark-based TT techniques, including a novel mid-sternum method. <b>Methods</b>: In this retrospective study, chest computed tomography scans of 245 adult trauma patients who presented to a Level I trauma center in Korea between February and June 2022 were analyzed. TT insertion routes using the mid-sternum, nipple, and mid-arm point methods were compared against the conventional fifth intercostal space (ICS) method. <b>Results</b>: Of the 245 enrolled patients, the median age was 55.0 years (interquartile range, 42.0-64.0), and 186 (75.9%) were male. On the right side, routes avoiding the diaphragm were observed in 82.0% (fifth ICS), 92.7% (mid-sternum), 55.5% (nipple), and 90.2% (mid-arm point) of patients. The mid-sternum method showed a significantly higher avoidance rate than the fifth ICS method (<i>p</i> < 0.001), with 91.1% sensitivity and 77.4% specificity for identifying TT routes within the safety zone. On the left side, routes avoiding the diaphragm were observed in 97.6% (fifth ICS), 98.8% (mid-sternum), 86.9% (nipple), and 95.1% (mid-arm point) of patients, with no significant difference between the fifth ICS and mid-sternum methods (<i>p</i> = 0.375). The mid-sternum method showed 90.4% sensitivity and 85.2% specificity for routes within the safety zone. <b>Conclusions</b>: The mid-sternum method demonstrated high anatomical safety and performance comparable to or superior to the conventional fifth ICS method, particularly in minimizing the risk of diaphragmatic injury. It may offer a practical and safe alternative for TT placement in trauma care.