Characteristics, outcomes, and prognostic factors in patients with penetrating and blunt traumatic diaphragmatic injury: a nationwide retrospective cohort study in Japan

Abstract

Background Traumatic diaphragmatic injury (TDI) is well-known worldwide as rare and life-threatening. However, because no nationwide cohort study of penetrating and blunt TDI has been conducted in Japan and other countries where penetrating trauma is relatively uncommon, the clinical characteristics of all TDI are unknown. Our purposes were to describe the characteristics of TDI patients, to compare penetrating TDI with blunt TDI, and to identify risk factors for mortality in Japan. Methods We retrospectively identified TDI patients between 2004 and 2019 using data from the Japan Trauma Data Bank. We extracted data on patient demographics, type of trauma, cause of trauma, physiological parameters, region of concomitant injury, associated injury, and management. We compared penetrating TDI and blunt TDI for each variable. The primary outcome was mortality. Multivariable logistic regression analysis was performed to identify risk factors for mortality. Results A total of 1147 patients (0.3%) had TDI, of which 771 were eligible for analysis (excluding 308 in cardiac arrest on arrival). Blunt TDI represented 70% and penetrating TDI 30%. In penetrating TDI, the most common cause was self-inflicted (49%), and compared to blunt TDI, males were 69% of patients (vs. 66%; P = 0.50) and the mortality rate was 8.3% (vs. 26%; P < 0.001). Multivariable analysis found that age (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.01–1.04), Injury Severity Score (OR 1.03, 95%CI 1.006–1.06), Revised Trauma Score (OR 0.55, 95%CI 0.45–0.67), severe concomitant abdominal injury (OR 2.45, 95%CI 1.32–4.56), severe concomitant upper extremity injury (OR 3.38, 95%CI 1.24–9.17), computed tomography (CT) (OR 0.32, 95%CI 0.15–0.69), and diaphragm repair (OR 0.44, 95%CI 0.25–0.78) were independent predictors of mortality. Conclusions In Japan, we found that penetrating TDI was mainly caused by self-injury and the male-female ratio was the same as for blunt TDI, although blunt TDI was much more frequent. TDI was considered highly lethal, with over 25% of patients in cardiac arrest on arrival. Our unique independent predictors were CT, severe concomitant abdominal injury, and severe concomitant upper extremity injury. These findings may help in the management of TDI in countries with less common penetrating trauma.