Normal Testicular Perfusion
Healthy cord, unobstructed arterial and venous flow.
- Normal: Testicular artery flow (continuous diastolic flow)
- 0°: Cord twist (no torsion present)
- Intact: Cremasteric reflex (normal exam finding)
- 100%: Tissue viability (fully perfused)
The spermatic cord
Carries artery, veins, vas deferens, and nerves.
Normal Doppler signal
Color flow fills the testicle symmetrically.
Why this baseline matters
Every torsion case departs from this healthy picture.
Acute Scrotal Pain Onset
Sudden, severe unilateral pain is the classic red flag.
- Sudden: Pain onset (often woke from sleep)
- 12–18: Peak incidence age (years old)
- Common: Nausea / vomiting (accompanies severe pain)
- Ticking: Time is tissue (clock starts at onset)
Sudden pain vs gradual pain
Abrupt onset raises torsion suspicion sharply.
Associated symptoms
Nausea, vomiting, and a high-riding testis often follow.
Why speed matters
Every stage from here is a race against ischemia.
TWIST Score Assessment
A bedside score estimates torsion probability before imaging.
- 0–7: TWIST score range (points, five exam items)
- ≥5: High-risk threshold (go straight to surgery)
- 0–1: Low-risk threshold (torsion very unlikely)
- 5: Exam items (swelling, reflex, position, more)
What TWIST measures
Testicular swelling, hardness, high position, nausea, absent reflex.
Scoring the exam
Each finding adds points toward a torsion likelihood.
Guiding next steps
High score can bypass ultrasound and go to the OR.
Doppler Ultrasound
Color Doppler visualizes blood flow directly inside the testicle.
- ~90%: Sensitivity (for detecting torsion)
- Absent flow: Key finding (confirms torsion)
- Cord twist: Whirlpool sign (seen on grayscale)
- Minutes: Study speed (must not delay surgery)
Reading the flow signal
Color pixels vanish as the cord chokes off supply.
The whirlpool sign
Spiraled cord fibers appear twisted on grayscale imaging.
A confirmatory, not gatekeeping, test
High clinical suspicion should not wait on ultrasound.
Critical Time Window
Salvage rates collapse the longer detorsion is delayed.
- ~90%: Salvage <6 h (testicle usually saved)
- ~50%: Salvage 12–24 h (declining rapidly)
- <10%: Salvage >24 h (orchiectomy often required)
- <1 h: Target door-to-OR (true surgical emergency)
Why 6 hours
Ischemic injury becomes irreversible past this point.
Detorsion and fixation
Cord is untwisted, then both testes are anchored.
When salvage fails
Necrotic tissue requires orchiectomy to prevent infection.