Diagnosing with a TWIST: Systematic Review and Meta-Analysis of a Testicular Torsion Risk Score.

Abstract

The Testicular Workup for Ischaemia and Suspected Torsion (TWIST) score is a seven-point tool to evaluate acute scrotal pain. Parameters include testicular swelling (2 points), hard testis (2), high-riding testis (1), absent cremasteric reflex (1), and nausea/vomiting (1). This review aimed to determine the diagnostic utility of TWIST and its role in risk stratification. A systematic review and meta-analysis of diagnostic test accuracy (MADTA) was conducted. Five risk stratification systems were explored, including Barbosa 2013 (0-2/3-4/5-7) and Sheth 2016 (0/1-5/6-7), to obtain sensitivity, specificity, and area under the receiver operating curve (AUC). Thirteen studies were identified, nine prospective studies proceeded to MADTA, five paediatric studies (1060 patients, 199 torsions) were included in the primary analysis. The most accurate risk stratification system was Barbosa (0-2/3-4/5-7) with an AUC of 0.924 [95% CI: 0.865, 0.956]. Barbosa showed favourable sensitivity in low-risk patients (0.984), facilitating rule-out of torsion, and favourable specificity (0.975) in high-risk patients, facilitating urgent surgical exploration. Sensitivity and specificity in intermediate-risk patients were 0.922 and 0.682, respectively, indicating a need for further workup with ultrasound. Using this stratification, 65.2% of patients were low-risk, 19.9% were intermediate-risk, and 14.9% were high-risk. Per 100 presentations of acute scrotum, there was a missed torsion rate of 1.6/100, ultrasound rate of 19.9/100, and negative exploration rate of 2.5/100. TWIST is an effective tool for suspected testicular torsion and is appropriate for widespread adoption. The Barbosa scoring system is reliable and reduces the reliance on scrotal ultrasound.