The TWIST score is a "validated" clinical decision instrument to aid in the diagnosis of acute testicular torsion.
Yes, I’ve never heard of it either… and I will probably forget about it very soon.
The TWIST score (0-7) is calculated by the presence of testicular swelling (2 points), hard testes (2 points), nausea/vomiting (1 point), high riding testes (1 point), and absent cremasteric reflex (1 point). Based on the score, patients can be stratified into high, intermediate, or low risk. I’ll spare you further details…
These authors sought to apply the TWIST score to a group of patients by performing a retrospective medical record review. They were looking at potentially decreasing formal ultrasound use, decreasing ED length of stay and ischemic time. (Methods for their chart review are absent however…)
77 patients were identified by ICD-10 codes. All 9 high risk patients had torsion. And it was absent in the 57 low risk patients. The authors claim the score could have reduced the need for ultrasound 75% of the time and reduced ischemia time.
Sounds great, but there are major problems with this study.
Retrospectively collected data is usually poor quality. The authors assumed data not recorded indicated absence of findings. Of course, this is nuts (sorry).
Regardless of prior studies, I don’t believe the TWIST score has face validity. The most important features in diagnosis of torsion are the appropriate age (usually adolescent) and the history. Sudden severe pain with vomiting and potentially a high-riding testicle is all you need. These patients should not be getting ultrasounds… just an immediate referral to the appropriate surgeon. A hard & swollen testicle is very common in orchitis and I can’t believe it wound be discriminatory.
Of course, a clinical decision instrument should improve upon what we do already. These scores must be compared to clinician gestalt before being adopted. Otherwise we don’t know if they will underperform and cause harm.
Regardless of what Cubby Checker says, please don’t do the TWIST.
Roberts CE, Ricks WA, Roy JD, et al. Testicular Workup for Ischemia and Suspected Torsion in Pediatric Patients and Resourse Utilization. J Surg Res. 2021;257:406-411. [link to article]