Congenital structural abnormalities of genital tract

Question 1

Embryological development of the female genital ducts and glands:

Answer 1

• Absence of SRY gene leads to differentiation of indifferent gonads into ovaries.
• Absence of AMH (produced by testis) leads to persistance of paramesonephric (Müllerian) ducts.
• Absence of testosterone leads to regression of mesonephric (Wolffian) ducts.
• Fallopian tubes: arise from unfused cranial portion of the paramesonephric ducts.
• Uterus and upper 2/3rds of vagina: arise from the uterovaginal primordium, the fused caudal portion of the paramesonephric ducts.
  
  • Fusion occurs around 6 weeks.
  • Canalisation then occurs to form the uterine cavity.
• Hox gene is responsbiel for regulating developement of female genital ducts.
• Fusion of the paramesonephric ducts also forms a peritoneal fold that becomes the broad ligament.

Question 2

Embryological development of the vagina:

Answer 2

• Vaginal epithelium derived from the endoderm of the urogenital sinus.
• Vaginal fibromusclar wall develops from the surrounding mesenchyme.
• Lower 1/3rd of vagina:
  
  • Forms from the fusion of the paired sinovaginal bulbs (endoderm outgrowths) which extends from the urogenital sinus to the caudal end of the urogenital primordium.
  • The sinovaginal bulbs fuse to form a vaginal plate.
  • Central portion of the vaginal plate breaks down to form the vaginal lumen by third trimester.
  • Vagina is is separated from the cavity of the urogenital sinus by the hymen membrane (an invagination of the posterior wall of the urogenital sinus.
  • In the first 28 days of life the hymen membrane ruptures and remains as a thin mucous membrane just within the vaginal orifice.

Question 3

MRKH syndrome:

What anomaly results in MRKH syndrome?

Describe the anatomical abnormalities associated with MKRH syndrome.

Answer 3

Müllerian agenesis or hypolasia resulting in:

• Absent or rudimentary uterus
• or bilateral rudimentary horns on either pelvic side wall.
• Vaginal agenesis

Question 4

What anomalies result from lateral fusion defects?

Answer 4

• Failure of resorption resulting in a uterine or longitudinal vaginal septum
• Failure of formation of one of the two Müllerian ducts
• Failure of duct migration
• Failure of Müllerian ducts fusion: resulting in didelphus or bicornuate uterus.

Question 5

What anomalies result from vertical fusion defects?

Answer 5

• Defective fusion of the caudal end of the Müllerian ducts: cervical agenesis or dysgenesis
• Defective fusion of the caudal end urogenital sinus: transverse vaginal septum.
• Defective vaginal canalisation: segmental vaginal agenesis

Question 6

What synthetic oestrogen medication used to prevent pregnancy loss from 1949 to 1971 is associated with a variety of female genital tract anomalies?

Answer 6

In utero exposure to diethylstilbestrol (DES)

Question 7

List some non-pregnant complications associated with congenital structural abnormalities of the genital tract:

Answer 7

• Pelvic pain, cyclic or non-cyclic.
• Amenorrhoea:
  
  • Hematometra (blood-filled uterine cavity)
  • Hematocolpos (blood-filled vagina)
• Retrograde-menstruation and development of endometriosis.
• Abnormal uterine bleeding or discharge
• Genital tract infection
• Dyspareunia

Question 8

Regarding pregnancy complications and congenital structural abnormalities:

List proposed mechanisms of complication and associated complications.

Answer 8

• Small uterine cavity:
  
  • IUGR
  • Preterm delivery
  • Malpresentation
  • Caesarean section delivery
  • Rupture of rudimentary horn.
• Obstructed birth canal / vaginal septum:
  
  • Caesarean section delivery
  • Haemorrhage during labour and postpartum
  • Placental attachment abnormalities
• Abnormal uterine vascularture:
  
  • IUGR
• Coexistent congenital renal abnormalities:
  
  • Pregnancy related hypertension
• Unfavourable implantation sites/structures:
  
  • Spontaneous miscarriage
  • Recurrent miscarriage
  • Ectopic pregnancy
• Cervical insufficiency:
  
  • Preterm delivery

Question 9

Evaluate the role of hysterosalpingogram (HSG) for congenital structural abnormalities of the genital tract:

Answer 9

• Gives more information than an ultrasound about the interior contour of the uterine cavity.
• Helpful for planning surgical resection of uterine septums: length and width of septum.
• Cannot assess external uterine contour so cannot differentiate between septate and biconurate uterui.

Question 10

Evaluate the role of MRI for congenital structural abnormalities of the genital tract:

Answer 10

• Indicated for:
  
  • Inconclusive ultrasound
  • Complex anomalies
  • Intolerate of internal exam/probe
• May not identify rudimentary uterine horn if lying laterally along psoas muscle and pelvic sidewall.

Question 11

Arcuate uterus:

Outline the:

• Diagnosis
• Clinical significance
• Management of

Answer 11

• Diagnosis:
  
  • Deviation of the endometrial cavities at the fundus.
  • <1 cm fundal indentation
  • Angle of indentation >90 degrees
• Clinical significance:
  
  • Normal variant, no clinical consequences
• Management:
  
  • None

Question 12

Septate or subseptate uterus:

Outline the:

• Aetiology
• Diagnosis
• Clinical significance
• Management

Answer 12

• Aetiology:
  
  • Failure of canalisatio of two fused Müllerian ducts OR
  • Failure of resorption of midline septum
• Diagnosis:
  
  • Two closely separated enodmetrial cacities
  • Smooth fundal contour
• Clinical significance:
  
  • Can have complete septum with TWO cervixes.
  • Increased risk of spontaneous miscarriage, recurrent miscarriage, preterm birth, IUD, malpresentation, placental abruption.
• Management:
  
  • Hysteroscopic resection with concurrent laparoscopy to prevent perforation.
  • Benefits:
    • Low perioperative morbidity
    • Lower pregnancy complications as avoids transmyometrial incisions.
    • Short recovery
    • Lower risk of infection and intra-abdominal adhesions
  • Risks:
    
    • Intrauterine synechiae (rare)
    • Post-op infection (rare)

Question 13

Bicornuate uterus is associated with what pregnancy complications?

Answer 13

• Cervical insufficiency
• Spontaneous miscarriage
• Fetal demise
• IUGR
• Malpresentation

Question 14

What surgery could you perform for a bicornuate uterus?

What is the indication for this procedure?

What are the risks of this procedure?

Answer 14

• Strassman procedure: open uterine reunification.
• Indication: indentation >1 cm and history of poor pregnancy outcomes.
• Risks:
  
  • Uterine rupture (scarred uterus)
  • Intra-uterine adhesions
  • Laparotomy associated risks

Question 15

Unicornuate uterus:

What diagnostic imaging findings are associated?

What complications are associated?

What surgical management may be offered?

Answer 15

• Diagnostic imaging:
  
  • Uterus deviated to one side
  • MRI: presence of rudimentary horn
• Complications:
  
  • Cyclical pain, endometritis
  • Preterm delivery
  • Malpresentation
  • Ectopic pregnancy
  • Miscarriage
  • Fetal demise
  • Uterine rupture
  • Abnormal placentation
• Surgical management: laparoscopic resection of rudimentary horn containing endometrium.

Question 16

What is the incidence of MRKH syndrome?

Answer 16

1 in 4000 - 6000

Question 17

What other anomalies are associated with MRKH syndrome?

Answer 17

• Renal (25-50%)
• Skeletal (up to 15%)

Question 18

What are the causes of upper vaginal agenesis or hypoplasia?

Answer 18

• MRKH syndrome (46XX)
• Androgen insensitivity i.e. CAIS (46XY)

Question 19

Outline briefly the surgical options for upper vaginal agenesis or hypoplasia:

Answer 19

• McIndoe-Reed procedure: skin graft mounted on mould and sutured between urethra and rectum.
• Bowel vaginoplasty: laparotomy where sigmoid segment is mobilied and sutured to introitus; distal end closed.
• Davydov procedure: pelvic peritoneum sutured to introitus and closed distally.
• Laparoscopic Vecchietti procedure: acrylic olive placed in vaginal dimple and has sutured mounted on a tension device that gradually pulls olive to form a neovagina.