• Clinical science

Testicular torsion


Testicular torsion is the sudden twisting of the spermatic cord within the scrotum. It most commonly affects children and young men. Because of the risk of ischemia and possible infarction of the testicle, it is considered a urological emergency. Testicular torsion is characterized by sudden-onset unilateral testicular pain, which may radiate to the lower abdomen, with nausea and vomiting. Clinical findings include a high-riding testicle with an absent cremasteric reflex. The diagnosis is confirmed on ultrasound. Testicular torsion (including suspected cases) requires prompt surgical correction within six hours of symptom onset to prevent complications. Important differential diagnoses include orchitis and epididymitis, and should be ruled out before initiating treatment.


  • Peak incidence: neonatal period (first 30 days of life) and during puberty
  • Accounts for 10–15% of acute scrotal illness in children within the United States
  • Predisposing factors, especially in adults: testicular malignancy
  • Prevalence: 3.8/100,000 males below the age of 18


Epidemiological data refers to the US, unless otherwise specified.


  • Idiopathic
    • Hypotheses include the bell-clapper deformity (intravaginal torsion; see "Pathophysiology" below) or a prolonged mesorchium
    • In neonates, the entire tunica vaginalis undergoes torsion (extravaginal torsion).
  • Iatrogenic
  • Occurs in very rare cases as a result of trauma



  • Intravaginal torsion: most common; occurs in older children and young adults
  • Long mesorchium: occurs in children
  • Extravaginal torsion: occurs in neonates



Optimal sperm development requires that both testicles descend from the intra-abdominal space into the scrotum. Transabdominal migration of both testicles is usually complete by the 32nd week of gestation, although it may occur later in life. The descending testicle is supported by a layer of peritoneum, which is termed the tunica vaginalis. This tunica vaginalis is normally secured to the superior and inferior posterior pole of the testicle. With the assistance of the gubernaculum at the lower pole, the testicle is pulled into the scrotum. The spermatic cord, which holds the vas deferens and testicular vasculature, meets the testicle within the scrotum.


  • Testicular torsion involves a sudden twisting of the spermatic cord associated with a poorly secured testicle.
  • Three types of testicular torsion may be identified:
    • Intravaginal torsion[4]
      • Hypotheses suggest this occurs because of a congenital abnormality in which the tunica vaginalis only attaches to the superior pole of the testicle (may occur in both testicles) → bell-clapper deformity (increased mobility of testicle within tunica vaginalis, with possible abnormal transverse lie of testicle) → torsion of the testicle (along the spermatic cord)
    • Long mesorchium
      • Prolonged mesorchium → torsion of the testicle (along the mesorchium)
    • Extravaginal torsion
  • Torsion result in venous engorgement with consequent arterial compromise, tissue ischemia, and possible infarction. Irreversible damage occurs after approx. 6–12 hours of torsion.


Clinical features

  • Abrupt onset testicular pain and/or pain in the lower abdomen
    • Typically swollen and tender testicle and/or lower abdominal tenderness
  • Nausea and vomiting
  • Abnormal position of testicle
    • Abnormal transverse lie
    • Scrotal elevation
    • Possible undescended testes (predisposes to testicular torsion)
  • Absent cremasteric reflex
  • Prehn sign: negative
  • In neonates
    • Possible absent testicle
    • Firm, painless scrotal mass – either enlarged or atrophied
    • Possible acute inflammation: swollen, erythematous (or blue discolored in venous engorgement), and tender hemiscrotum

Testicular torsion should always be suspected in a male patient with severe, sudden-onset testicular pain!



Laboratory tests

Ultrasound of the scrotum

  • Indications:
    • Ambiguous clinical findings
    • Low suspicion of testicular torsion
  • Gray-scale ultrasound
    • Twisting of spermatic cord
    • Initial testicular homogeneity that becomes heterogenous after 24 hours when necrosis occurs
  • Doppler ultrasound: reduced perfusion in the affected testicle
    • Increased resistance index in the intratesticular arteries
    • Decreased flow velocity in the intratesticular arteries

Surgical intervention is recommended for suspected testicular torsion, regardless of radiological findings!

Differential diagnoses

Differential diagnosis of scrotal pain
History Examination Lab tests
Testicular torsion
  • Sudden onset (patients usually present < 24 h from onset of symptoms)
  • Unilateral painful testicle/lower abdomen
  • Nausea or vomiting
  • Swollen, edematous, tender testicle
  • Abnormal position of testicle (e.g., transverse lie, scrotal elevation)
  • Negative Prehn sign
  • Absent cremasteric reflex
  • Gradual onset (e.g., a few days if acute or weeks if chronic)
  • Painful swelling with possible induration
  • Possible history of urethral discharge
  • Fever, dysuria, urinary frequency
Testicular tumor
  • Slow progression (e.g., weeks to months)
  • Usually painless mass (however, may feel dull ache or "heavy" sensation in the testicle)
  • Easy palpation of solid mass
  • Possible manifestations of metastatic disease (e.g., distant lymphadenopathy, chest pain, gastrointestinal symptoms)
  • Possible ipsilateral lower limb swelling (venous engorgement due to obstruction)
Torsion of testicular appendage (hydatid of Morgagni)
  • Insidious onset of unilateral scrotal pain
  • Usually boys 3–5 years old
  • Tender testicle
  • Palapable blue dot often present (blue dot sign)

Torsion of testicular appendage (hydatid of Morgagni)

  • Description: The hydatid of Morgagni (appendix of the testes) is an embryological remnant on the upper pole of the testes or at the epididymis (the remnant of the Müllerian duct). This hydatid of Morgagni has the potential to rotate. The resultant symptoms resemble acute testicular torsion.
  • Clinical features
    • Typically boys 3–5 years old
    • Insidious unilateral scrotal tenderness
    • "blue dot sign"
  • Imaging: doppler ultrasound may show an enlarged testicular appendix and or mild hydrocele with preserved testicular blood flow
  • Management: A conservative approach with NSAIDs may be considered. However, if in doubt, surgical intervention is required to examine the testes.


The differential diagnoses listed here are not exhaustive.


  • Testicular torsion is a medical emergency and should be treated upon suspicion within 6 hours of the onset of symptoms to prevent loss of the testis.
  • Immediate surgical exploration of the testicle with reduction (untwisting) and orchidopexy
  • Orchidopexy (fixation) of the contralateral side is recommended
  • Manual detorsion may be attempted to possibly buy time and relieve symptoms, but is not a replacement for surgical exploration
    • If surgery is not possible within the recommended window of intervention:
      • Trial of conservative maneuver: turn the testicle towards the lateral direction (left testicle → clockwise; right testicle → counterclockwise).
      • Still perform surgical exploration as a trial of treatment when outside the preferred window of treatment

Because of the risk of significant consequences for (often young) patients, surgical exploration of the testicle is recommended in cases of suspected testicular torsion!



  • Timely intervention within the recommended time period (6 hours from symptom onset) → restoration to previous condition
  • Late or absent surgical intervention → ischemianecrosis of the testicles