Testicular torsion-detorsion syndrome

Last revised by Henry Knipe on 1 Feb 2023

Testicular torsion-detorsion syndrome or intermittent testicular torsion refers to acute and periodic testicular pain due to limited blood flow, integrated with asymptomatic periods 1. Testicular torsion-detorsion syndrome has increasingly been reported in the literature.  

Testicular torsion can happen at any age but generally affects 1 in 4000 males younger than 25 years old per year 2,3.

Spontaneous resolution of acute scrotal pain concomitant with hyperemia on color Doppler imaging may suggest the diagnosis. Diagnosis can be made by careful analysis of the morphologic features and amplitude of the spectral Doppler waveform in comparison with the contralateral testis or a different area within the same testis 3,4,10. Active close follow-up will be helpful in differentiation between epididymo-orchitis and spontaneously detorted testis 1,2,4,7.

Brief periods of acute groin pain followed by spontaneous relief of the symptoms may be a typical history in these patient cases 4-6.

In neonates, the most common form of torsion is extravaginal or supravaginal where the whole content of the hemiscrotum twists around the spermatic cord at the level of the external inguinal ring.

In young adults or adolescents, the more expected torsion is intravaginal. The most common underlying abnormality is the so-called bell clapper deformity. This deformity is noted in 5-16% of males and is bilateral in 66-100% of cases 2,3.

Although ultrasound is the choice modality for evaluating the potentially torsed testis it is not helpful for the diagnosis of torsion-detorsion syndrome.

When a symptomatic testicle has hyperemia on color Doppler imaging in the presence of a sonographic “whirlpool sign” it helps to make a definite diagnosis 4,7. It is crucial to recognize that epididymo-orchitis can closely mimic the clinical and sonographic findings of spontaneously detorted testis 2.

Color Doppler imaging findings of torsion-detorsion syndrome include elevated resistive index (RI >0.75) and to-and-fro flow or reversed diastolic flow, which have also been reported in severe epididymo-orchitis 3, 7-9.

Given that torsion-detorsion syndrome ultimately will progress to acute testicular infarction, an elective orchiopexy in smaller series has shown an excellent outcome 5,6.

General imaging differentials include 10,11:

  • epididymo-orchitis can mimic both:
    • torsed testis due to increased intratesticular pressure
    • spontaneous detorsion with reactive hyperemia
  • torsion of the epididymal appendix
    • more of a clinical differential diagnosis
    • testis and epididymis are normal
    • small pedunculated avascular nodule may be seen and be very tender
  • acute idiopathic scrotal edema
    • scrotal wall swelling and edema are characteristic
    • can be unilateral or bilateral
    • marked hypervascularity of the thickened scrotal wall gives rise to the fountain sign on color Doppler ultrasound
    • testis and epididymis are normal in appearance
  • testicular trauma

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Cases and figures

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