Age: Most cases occur from12 to 18 years of age. It is uncommon before 8 years of age and after 35.
Site and mechanism of the torsion:
(1) Most torsions after infancy occur within the scrotal sac (intravaginally, within the tunica vaginalis), while in the neonate many occur in the inguinal canal (extravaginally).
(2) Many cases involve the "bell-clapper" deformity, in which the tunica vaginalis extends around the entire testis and high up around the spermatic cord, which allows the testis to be more mobile. Normally the epididymis and posteroinferior surfaces of the testis are not covered by the tunica but rather are attached to the scrotal wall.
(3) The cremasteric muscle fibers determine the direction of rotation for the affected testis. The left testis tends to rotate clockwise when viewed from below, while the right rotates counterclockwise.
Clinical findings:
(1) The patient typically has a painful swelling of the scrotum and may be unable to walk. The onset is often sudden but it may be gradual or episodic. Occasionally the swelling may be painless.
(2) The affected side of the scrotum is usually erythematous and tender on palpation.
(3) The affected testis lies higher than the unaffected testis.
(4) If the patient stands, the unaffected testis will lie horizontal rather than vertical (Angell's sign).
(5) The patient may show nausea and vomiting.
(6) Some cases may follow strenuous exercise, trauma or sexual intercourse.
(7) Rarely the torsion can be bilateral.
Doppler ultrasonography may be helpful for determining the presence or absence of blood flow to the affected testis,
Differential diagnosis:
(1) acute bacterial epididymo-orchitis (for a completely descended testis)
(2) strangulated inguinal hernia (if the testis is in the inguinal canal)
If surgery can be performed early enough then the testis may be salvaged. The opposite testis (also the salvaged testis) should be fixed in place with a non-absorbable suture (orchipexy).
