Evaluation of the Diagnostic Performance of the Testicular Workup for Ischemia and Suspected Torsion (TWIST) Score for Assessing the Risk of Testicular Torsion in Adult Patients Presenting to the Emergency Department With Scrotal Pain - A Prospective Observational Study

Acute scrotal pain is a common presentation in Emergency Departments, but the diagnosis of testicular torsion (TT) is relatively rare. Prompt identification is crucial because TT requires urgent surgical intervention to preserve testicular viability. Delays in diagnosis, particularly due to unnecessary imaging or non-standardized clinical assessment, may result in testicular loss.

The TWIST (Testicular Workup for Ischemia and Suspected Torsion) score is a clinical decision tool developed and validated in pediatric populations to stratify risk of TT based on five clinical features: testicular swelling, hard testis, high-riding testis, absent cremasteric reflex, and nausea/vomiting. Adult validation is limited, and no large-scale multicenter study has evaluated its performance in adult Emergency Department settings in Sweden.

This study will prospectively collect structured clinical data from adult patients aged 18-40 years presenting with scrotal pain at participating Swedish EDs. The TWIST score will be calculated from documented clinical findings. The study does not influence clinical management; patients will receive standard care, including imaging or surgical intervention as deemed appropriate by treating clinicians.

Primary objectives focus on the diagnostic accuracy of TWIST for ruling out TT in low-risk patients, while secondary objectives include assessment of the score in identifying high-risk patients, measurement of time to surgery, evaluation of pain scores, and analysis of imaging utilization. Data will also be linked to the Swedish Perioperative Register (SPOR) for outcomes such as surgery performed, complications, and final diagnoses.

The study is designed to evaluate whether structured use of TWIST can support evidence-based, standardized risk stratification in adults, potentially improving patient outcomes, streamlining resource use, and reducing unnecessary delays in diagnosis and treatment. Ethical oversight is provided by the Swedish Ethical Review Authority (Etikprövningsmyndigheten, decision 2025-07400-01).

Primary outcomes

• Diagnostic Accuracy of the TWIST Score (Low-Risk Group) [Up to 30 days from ED visit]: Number and proportion of adult patients with a low-risk TWIST score (0-2) who are confirmed not to have testicular torsion based on surgical exploration or follow-up within 30 days. This measures the sensitivity of the TWIST score to safely rule out torsion.

Secondary outcomes

• Time to exploration [30 days from ED visit]: Time in hours from patient arrival in the Emergency Department to surgical intervention for suspected testicular torsion.
• Testicular torsion [30 days from inclusion]: Number of testicular torsions found up to 30 days from ED visit
• Pain at study inclusion [Up to one hour from inclusion in the study.]: Pain at inclusion to the study measured by NRS
• Use of Ultrasound [Up to 48 hours from inclusion or ED discharge, whichever comes first]: If ultrasound was used during the Emergency Department visit

Sex: Male, ages: 18 Years to 40 Years

Inclusion Criteria:

* Male patients aged 18-40 years

Presenting to the Emergency Department with acute scrotal pain or scrotal symptoms

Suspicion of testicular torsion before clinical assessment

Exclusion Criteria:

* Scrotal pain or symptoms caused by trauma

Symptom duration > 1 week

History of testicular surgery

Inability to provide informed consent (e.g., language barrier or cognitive limitation)

• Jens Wretborn, MD, PhD, Principal investigator, Linkoeping University Hospital

NIH grants: 2025