Pediatric Testicle Torsion | Pediatric Radiology Reference Article | Pediatric Imaging

Etiology Extravaginal in Perinatal period and Infants:
— Twisting of spermatic cord superior to scrotum which compromises testicular circulation (venous flow more than arterial flow)
— Tunica vaginalis is not securely attached to scrotum with deficient fixation of spermatic cord
— Spermatic cord and testis loosely attached to surrounding structures and scrotal soft tissues are not yet anchored to scrotal skin
— Less likely to be bell clapper deformity
Etiology Intravaginal in Adolescents:
— Associated with bell-clapper deformity and intrascrotal twist of spermatic cord which compromises testicular circulation (venous flow more than arterial flow)
— Tunica vaginalis surrounds entire testicle and epididymis and prevents fixation to scrotal wall and allows for rotation of spermatic cord
— Twisting of excessively mobile testis, tunica vaginalis inserts abnormally high on spermatic cord
Imaging US:
— Evolution of appearance of testicle – first few hours testicle has normal echotexture which leads to 4-6 hours where testicle is enlarged and hypoechoic (edema) which leads to greater than 24 hours and testicle heterogenous due to vascular congestion and hemorrhage and ischemia and it is usually nonviable
— Abnormal (transverse) lie of testis
— Twisted spermatic cord or spermatic cord knot (snail sign or whirlpool sign) – spiral twist of spermatic cord in inguinal ring or scrotal sac which occurs with complete and incomplete (less than 360 degree) torsion and is most sensitive and specific sign for testicular torsion
— Reactive hydrocele
— Edema of scrotal skin and partesticular tissues
— Enlarged epididymis
— Note: Bell-clapper deformity can be determined by seeing fluid around entire testis
Imaging US Spectral Doppler:
— Low or absent diastolic flow or elevated resistive index in pubertal or post pubertal testis is concerning
— Diastolic flow routinely not detected in prepubertal testis
Imaging US Color Doppler:
— Classically decreased flow in torsion but there can be normal perfusion in early active torsion or increased flow in intermittent torsion-detorsion
— Peripheral hyperemia on US Color Doppler is similar to nuclear medicine doughnut sign
— After testicular torsion is reduced there can be reactive testicular hyperemia
— May be difficult to obtain color and US Spectral Doppler in prepubertal testis
Imaging US key signs:
— Abnormal testicle architecture
— Absent flow in post pubertal testis
— Twisted spermatic cord
Imaging US pitfalls:
— Don’t let nonvisualization of a spermatic cord twist dissuade you in an otherwise concerning exam
— Don’t confuse tortuous spermatic cords with twisted spermatic cords
— Spontaneous detorsion and intermittent torsion – both may have decreased or no flow followed by increased flow
— Partial torsion – flow is present but decreased
— Epididymoorchitis can mimic torsion-detorsion events
DDX:
Complications: Infarcted testicle
Treatment:
— Immediate surgery as time is critical in order to salvage the testis as salvage rate is greater than 90% if detorsion occurs within 6 hours and 50% if after 12 hours
— Manual detorsion can be performed as temporizing measure followed by surgical detorsion
— Fixation of testis to scrotal wall
— Contralateral orchiopexy
— If not salvageable testis is removed
Clinical Perinatal Period:
— Considered to occur before birth or the first 30 days of life
— 10-20% of perinatal testicular torsion are bilateral
— Presents as painless palpable hard mass with pigmentation of scrotum
Clinical Infants and Adolescents:
— Acute onset unilateral scrotal pain
— Absent cremasteric reflex
— Painful red scrotum
— Can present with lower abdominal pain