Ovarian torsion Flashcards
Epidemiological or predisposing factors associated with an increased risk of ovarian torsion
- Adnexal mass
- Previous torsion
- Women of reproductive age
- Pregnancy (Because of laxity of ligaments in pregnancy and enlarged corpus luteum)
- Ovulation induction (Because of increased likelihood of theca lutein cysts resulting in increased ovarian volume)
- Previous pelvic surgery
- Developmental abnormality: excessively long fallopian tube or absent mesosalpinx
- Describe USS features commonly associated with ovarian torsion
Decreased or absent Doppler flow within the ovary
Heterogenous appearance of the ovarian stroma due to oedema and haemorrhage
Multiple small peripheral follicles (“string of pearls”) due to displacement oedema
Abnormal location of ovary- anterior to uterus or midline ovary
Free fluid in pouch of Douglas
Twisted pedicle leading to ‘whirlpool sign’ (uncommon)
2 limitations with USS diagnosis of ovarian torsion
a. Presence of the above findings vary across patients- false negatives e.g. blood flow may be present due to dual ovarian blood supply or may be intermittent ovarian torsion
b. False positives e.g. PCOS: peripheral follicles, cyst rupture, free fluid
May miss up to 30% ovarian torsion
What is the percentage of false negatives with USS?
Approx 30%, blood flow suggests a viable ovary but doesn’t rule out torsion
What is the blood supply to the ovary?
Ovarian artery and collaterals from the uterine artery
Research has shown which 5 signs or symptoms have the highest likelihood in predicting ovarian torsion?
a. Unilateral abdominal pain (4.1)
b. Vomiting (7.9)
c. Pain <8 hours (8.0)
d. Absence of leucorrhoea / metrorrhagia (12.6)
e. USS showing cyst >5cm (10.6)
Decision making aids for SO versus detorsion
Does it look malignant?
Is she menopausal?
Is her family complete?
Does it appear to reperfuse if the torsion is resolved / the mass is removed?
Is there a cause? *
“Even unfavourable looking tumours may be amenable to conservative surgery”
* Recurrence rate is HIGH if no cause is found, which means USO leaves patient with one ovary, and she has a good chance of torting the remaining one. Consider oophoropexy either unilateral or bilateral. Fertility effects of oophoropexy are unknown.
Risk of recurrence
If cause found and treated = 9.1%
If pregnant = 19.5%
If true ovarian torsion = up to 64%
Why are ovaries more resilient than testicles?
Testis only has one blood supply, ovaries have collaterals
Testis has a very high metabolic rate due to sperm turnover, ovaries relatively lower
Testis is very prone to antibody formation if the sperm-barrier is breached, leading to subsequent infertility. Ovaries do not appear to form antibodies
26 year old nullipara presents to ED with vomiting and acute onset severe left sided lower abdo pain of abdo pain of 6 hours duration. She is 9 weeks gestation with an IVF pregnancy. TV USS on admission shows a left sided 8cm ovarian mass with features highly suggestive of ovarian torsion. The intrauterine pregnancy is viable and consistent with dates.
You perform a laparoscopy 3 hours after she presented to ED, the ovary is black/blue and twisted 1-3 times around the infundibulopelvic and utero-ovarian ligaments.
Justify your decision to preserve this ovary at surgery:
- Appearance is likely due to haemorrhagic engorgement rather than necrosis (artery less likely to be compressed than veins)
• Timing is a more reliable predictor of viability – diagnosis and treatment has been swift therefore good prognosis (usually considered until 48 hours)
• Multiple studies have shown preserved ovarian function after detorsion
• She is young and nulliparous
• Malignancy is not suspected, and if it is then further staging surgery can be discussed at a later time.
• Possibility of corpus luteum supporting the pregnancy
