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Three Part Question

In [patients presenting with unilateral testicular pain] do [testicular ultrasound scans] enable [an accurate diagnosis of testicular torsion]?

Search Strategy

Databases: Medline (2017), Embase (2005-2022), Cochrane (2017)

Search terms: (“Testicular Pain” OR “Scrotal Pain” OR “Acute Scrotum”).mp AND (“USS” OR “ultrasound”).mp AND (“diagnostic test”).mp AND ("Testicular Torsion" OR "Spermatic Cord Torsion" OR "twisted testis").mp

Search Outcome

The search on Medline found one paper. The search on Embase found 35 papers. The search on Cochrane found one paper.

After duplications were removed, 35 papers remained; of these, seven were relevant to the three-part question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Valentino et al. 2011 Italy	50 patients with acute scrotal pain who underwent USS and contrast-enhanced-USS between 03/2005–12/2009.		6% had TT. USS had 76% sensitivity and 45% specificity. Colour-enhanced-USS had 95% sensitivity and 100% specificity.		Small sample
Boettcher et al. 2013 Germany	104 patients treated for acute scrotum between 01/2001–04/2012 in two medical facilities in Germany		11.5% had TT. USS had 87% sensitivity and 91% specificity for TT – sensitivity increased to 100% when combined with a clinical score, but specificity fell to 57%.		Small sample demographic
Liang et al. 2013 Canada	266 patients, aged 1-month to 17-years, with acute scrotum who underwent USS in Canada, between 07/2008–07/2011		USS for TT was 100% sensitivity, 97.9% specificity. CDUS had 1.9% false-positivity and 0% false-negativity. 3% of USS was inconclusive		Small number of TT patients.Patients with missing USS data weren’t included. Interpretation bias by radiologist reviewing images.
Friedman et al 2019 Canada	120 patients in Canada with acute scrotum, who underwent point-of-care USS between 03/2015–01/2018		10% had TT. Point-of-care USS had 100% sensitivity and 99.1% specificity for TT. TT was the only condition where all USS users agreed with the diagnosis.		Selection bias in the analysis. Concurrent conditions were not explored.
Gopal et al 2020 UK	50 patients who underwent scrotal examinations in 4 centres in Britain.		25% had TT. 40% had CDUS. CDUS had 100% sensitivity and 33.3% specificity for TT.		Small sample size. Time delay for surgery due to USS was not investigated.
Visalli et al. 2021 Italy	69 children with acute scrotum who underwent USS between 06/2018–12/2020.		11.59% had TT. MicroV had 100% sensitivity and 100% specificity for TT. Doppler had 87.5% sensitivity and 100% specificity for TT. There was no significance in accuracy between MicroV and Doppler (p-value 0.29)		No incomplete torsion cases were investigated. Small sample size.
Burud et al. 2020 Malaysia	53 patients with acute scrotum between 01/2013–12/2017, with complete USS results.		USS had 88.24% sensitivity and 68.40% specificity for TT. DCUS had 31.6% false-positivity and 11.8% false-negativity.		Some USS records were incomplete (limited sample)

Comment(s)

All papers found USS (or its derivatives) to have 76-100% sensitivity for TT, with four papers reporting 100%. This suggests USS is proficient in identifying TT patients. The evidence on USS specificity is less conclusive. The study by Valentino et al. suggests 45% specificity for USS, whilst Liang et al. argues 97.9%. Boettcher et al. shows that combining investigations reduces specificity but increases sensitivity(63). This is important for time-critical conditions, such as TT, because improving the ability to diagnose such conditions will result in faster, often more beneficial treatment. The paper by Valentino et al reported USS for non-TT conditions and found contrast-enhanced USS to detect 100% of malignant tumours. This highlights the need for USS in all acute scrotum presentations, not just in suspected TT. No papers clearly compared different USS users. USS is dependent on operator ability; thus, further research should be conducted to compare the sensitivity and specificity when used by different grade and speciality health professionals.

Clinical Bottom Line

Ultrasound is a vital investigation for patients with acute testicular pain. Anyone presenting with acute scrotum should undergo USS to rule out TT or tumours.

References

1. Valentino et al. Role of contrast enhanced ultrasound in acute scrotal diseases
2. Boettcher et al. Clinical and sonographic features predict testicular torsion in children: A prospective study
3. Liang et al. Retrospective review of diagnosis and treatment in children presenting to the pediatric department with acute scrotum
4. Friedman et al Accuracy of point-of-care ultrasound by pediatric emergency physicians for testicular torsion
5. Gopal et al Emergency scrotal exploration in children: Is it time for a change in mindset in the UK?
6. Visalli et al. Microvascular imaging ultrasound (MicroV) and power Doppler vascularization analysis in a pediatric population with early scrotal pain onset
7. Burud et al. Correlation of ultrasonography and surgical outcome in patients with testicular torsion