Performance of the TWIST Score Versus Clinical Acumen in the Diagnosis of Testicular Torsion in an Australian Paediatric Emergency Department

BACKGROUNDS: The Testicular Workup for Ischaemia and Suspected Torsion (TWIST) score, designed to reduce reliance on ultrasounds, has been validated in multiple studies in countries where scrotal ultrasound is routinely performed in acute scrotum presentations. It has not been validated in Australia to date. Scrotal ultrasound is also not routinely recommended for patients presenting with an acute scrotum in Australia. This study assessed TWIST's utility and validity in an Australian paediatric setting and compared it to clinical suspicion alone. METHODS: This prospective observation cohort study enrolled 307 patients aged 3 months to 18 years; 116 (37.8%) were assessed by Emergency Department (ED) doctors only, 81 (26.4%) by surgeons only and 110 (35.8%) by both. Doctors recorded their clinical suspicion of testicular torsion (nil/low/intermediate/high). TWIST scores were calculated post data collection. Sensitivity, specificity, negative and positive predictive values were calculated for TWIST values and clinical suspicion risk levels. Receiver Operator Curves (ROC) were constructed to analyse and compare TWIST and clinical suspicion. RESULTS: Area under the ROC (AUC) for ED TWIST score was 0.768 (95% CI = 0.674, 0.862). The AUC for ED clinical suspicion was 0.866 (95% CI = 0.791, 0.940) (p = 0.035). For surgeons, the AUC for TWIST was 0.876 (95% CI = 0.809, 0.943) and for clinical suspicion was 0.899 (95% CI = 0.822, 0.976) (p = 0.962). CONCLUSIONS: Our study found there was no evidence that TWIST is superior to clinical acumen alone, and there is some evidence that ED doctors' clinical acumen may perform better than TWIST.