Uterine Torsion in MaresStevie WillettVETE 402 Advanced Medical TerminologyWeek 8 Mid-Term

What is a Uterine Torsion and Which Mares Get It?

Malposition of the uterus• A twist of 90-360 degrees on the uterus’s

long axis.• A twist can either be clockwise or

counterclockwise.• Rarely involves the cervix or vagina.

Pregnant mares normally have uterine torsions.• Occurs typically mid to late

gestation/pregnancy (Gestation is 11 months in a mare)

Uterine torsions can also have concurrent intestinal blockage or the intestines can become incorporated or part of the torsion.

Clinical SignsWhat Will A Mare Do If She Has A Uterine Torsion?

Show signs of colic (abdominal pain):

Kicking at belly Excessive rolling Frequent pawing at

the ground Getting up and down

frequently Looking at abdomen

frequently

Additional clinical signs: Restlessness Lethargic (quiet,

depressed, not very responsive)

Anxiety (worried look on face, wide eyed, rapid breathing)

Anorexic (not wanting to eat)

Increased heart rate upon exam

Sedatives and pain medication will not last long.

Uterine torsion should be suspected in any pregnant mare showing signs of colic

Physical Exam What Will The Veterinarian Will Do?

The veterinarian will ask about the mare’s breeding history and her due date.

The Veterinarian will perform a complete physical exam: Temperature Heart Rate Respiration Rate Mucus membranes (Gums) will be assessed for color and

moistness. Capillary refill time will be assessed to determine perfusion

(blood flow) The veterinarian will listen for gastrointestinal sounds in the four

quadrants

Diagnostics:What Else Will The Veterinarian Do?

The veterinarian will perform a rectal palpation Uterine torsions in horses are typically diagnosed by rectal

palpation of the broad ligaments of the uterus. A tight broad ligament is felt coursing side to side in the

direction of the torsion A torsion can be either clockwise or counterclockwise There can be between a 90-360 degree twist with the normal

twist being 180 degrees The direction of the torsion can be determined by the

placement of the broad ligaments. Clockwise torsion in present if the left ligament is tightly

stretched along the top of the abdomen and courses toward the right lower abdomen with the right ligament diving downward along the right side of the body wall.

Additional Diagnostics Ultrasound of the

abdomen from the outside. The ultrasound will help

view the fetus to determine if the fetus is stressed or still alive.

An ultrasound can also determine the health of the uterus (Thickened or inflamed).

Concurrent gastrointestinal disease can also be determined by an ultrasound exam.

Abdominocentesis (Taking a sample of fluid from the abdomen with the use of a needle or cannula) This can also determine

if there is concurrent gastrointestinal disease.

The use of an ultrasound will help to insure that the uterus will not be harmed when taking a sample.

TreatmentsTreatment Should Start Immediately After

Diagnosis!How Will The Veterinarian Help The Mare?

Nonsurgical Treatment:Rolling the mare under general anesthesia while applying abdominal pressure with a plank.

The mare is place on her side toward the side of that the torsion is rotated.

The plank helps maintain the fetus and uterus in position while the mare is rolled around them. A moderate size person stands or kneels on the plank.

The mare is rolled several times until she has been rolled in a 360 degree direction.

The mare must be rolled in the direction of the torsion. Rectal palpation by the veterinarian will determine if

the torsion is resolved. If not resolved the procedure may need to be repeated.

After correcting the torsion the mare is recovered (woken up) and rectally palpated again while standing to ensure torsion is corrected.

If no improvement is seen within 1 hour surgical correction should be pursued.

NOTE: Nonsurgical options might be more successful in mare during the middle months of pregnancy. NOT recommended in full term mares

Advantages and Disadvantage to Rolling Mares With Uterine

Torsions Advantages

Ability to perform on a farm and in the field.

Does not cost as much as surgical correction.

May be more successful in mares during the middle of pregnancy

Disadvantages Several people are needed

to help roll the mare. The placenta may detach

prematurely Abortion may occur Mares death or fetal death

may occur. Uterine rupture may occur Does not allow

visualization of uterus or gastrointestinal lesions.

Rolling the mare may be unsuccessful.

Additional TreatmentWhat Happens If Rolling Did Not Help?

If the cervix is open and the mare is close to term or due date: (Rare since most torsions occur before term and due date) Manual rotation of fetus and uterus can be attempted.

A well lubed hand is passed in to the uterus to grasp the fetus. The fetus and uterus is gently and rocked gradually together until the

torsion is fixed. Obstetric chains (placed on fetus’s limbs) and a detorsion rod (placed in

uterus) can also be used to help with rotating the torsion This treatment is usually possible if the torsion is less than 270 degrees

rotated.

NOTE: Procedure could cause injury to the mare’s uterus or cervix or injury to the fetus.

Mare will enter stage 2 of labor after procedure which might require an assisted delivery.

Surgical CorrectionWhat Are Some Other Options For Correcting Uterine

Torsions?

Flank Incision

Ventral Mid-line Incision Approach

Flank Incision Approach The mare is standing Sedation is used to keep mare calm and quiet The flank area is blocked (numbed) with local anesthetic

so the mare cannot feel the area. Then the area is clipped and cleaned so it is sterile. Epidural anesthesia can be use, but risk of mare collapsing is a possibility

An ultrasound can be used during and after surgery to monitor the fetus or to confirm if fetus is dead.

Flank Incision Approach Continued:

The flank incision is made on the side toward which the uterus is twisted. An incision on the opposite side of the mare may also be needed if correction is difficult

2 incisions allows for a second surgeon to help with manipulation simultaneously The surgeon places his/her hand under the uterus horn which contains

the fetus. The uterus and fetus are rocked back and forth to allow the uterus to flip into normal position.

It is recommended to lift and push uterus and fetus rather than pull This will reduce the chance of puncturing a hole or breaking the uterus.

The uterus and broad ligaments will be felt to ensure the torsion was fixed. The fetus will also be assessed to ensure it is still alive.

If fetus is dead: The cervix can be dilated and fetus removed after torsion correction, C-Section can be performed soon after flank incision surgery, or the fetus will be expelled 1-2 days after surgery (Mare must be monitored close if assisted delivery is needed.

The remainder of the abdominal contents should be palpated to rule out concurrent disease

Advantages and Disadvantages to Flank Incision

Advantages Eliminates risk

associated with general anesthesia.

Less expensive Ideal for mares who are

not anesthetic candidates due to size (too big) or body system compromise

Disadvantages Correction of torsion

could be challenging or cannot be fixed while mare is standing. (Large foal or size of uterus).

This technique could be very painful for the mare.

The mare could collapse during surgery which could cause abdominal contents to fall out of incision.

Ventral Mid-Line Incision Approach

When Should a Ventral Mid-Line Incision Be Used?

If previous attempts to correct the uterine torsion have failed.

If there is concurrent gastrointestinal disease suspected. If the uterus has rupture or torn apart or a C-Section is

needed to remove the fetus. If the fetus is dead and the cervix remains closed. If the mare is showing to be in severe pain and might try

to collapse during the standing surgery.

Ventral Mid-Line Approach The mare will be placed under general anesthesia (will be asleep). The mare will be placed on her back on a surgery table. This procedure should be performed in a veterinary hospital.

Mechanical ventilation (a ventilator) will most likely be needed to keep the mare well oxygenated.

The mare’s pregnant uterus as well as being placed on her back puts pressure on lungs, thus reducing amount of oxygen mare is able to take in.

An incision will be made on the abdomen in front of the umbilicus (belly button).

A foal care team will be used to assist the foal after delivery (if the foal is alive). The foal care team will be used if a C-Section is needing to be performed.

20 liters (1 liter = about 1 quart)of warm 0.9% saline solution can be placed in the abdomen during surgery. This will get the uterus to “float” so manipulation and correction of torsion will be

easier and help reduce the risk of tissue damage.

Advantages and Disadvantages Of A Ventral Mid-Line Incision

Advantages Best surgical option for

failed nonsurgical rolling.

Access to abdominal cavity to allow assessment of uterus and abdominal contents (If concurrent gastrointestinal disease is present).

Disadvantages Cost might be to high. Increased risks

associated with general anesthesia.

Sutures and staples can come apart after surgery (during recovery) or during delivery of foal.

This could result in abdominal contents spilling out on ground and could end up with the death of the mare.

Postoperative Care After Flank and Ventral Mid-Line Incisions

Postoperative care will depend on mare and fetus, but usually include fluid therapy, antibiotics, and anti-inflammatory drugs.

Stall rest is needed for 30 days followed by additional 30 days in a small turnout area. This gives time for the incision to heal.

Rolling should be prevented so the reoccurrence of the uterine torsion does not happen again.

Mare should be monitored regularly for labor incase assistance is needed.

The mare may need to be maintained on supplemental progesterone (Regumate or similar drug) if the fetus is still alive until close to the due date.

This will ensure that the cervix remains closed, the uterus will not have contractions, and to prevent abortion of fetus

If the fetus remains alive close monitoring of fetus is needed to ensure it does not become distressed or become compromised and die

Complications Of Uterine Torsions Premature placental separation Uterine wall necrosis (tissue death) Uterine rupture Adhesions (union of 2 surfaces that are normally

separated) Surgery within the abdomen can sometimes cause adhesions

Reoccurrence of uterine torsion Peritonitis (inflammation of the peritoneum within the

abdominal cavity) Fetal death or Abortion

Signs of fetal death or impending abortion: Udder develpoment, loss of cervical mucus plug, vaginal or vulvular

discharge, restlessness

Fetal and Neonatal Complications After Uterine Torsions

Death of Fetus Lack of oxygen to fetus due to decrease blood flow

during torsion. Resulting in increase risk for hypoxic-ischemic

encephalopathy Neonatal complications increase and are more common

when uterine torsion occurs after 320 days of pregnancy Birth of the fetus should be considered high risk

Prognosis If the gastrointestinal tract was not involved and minimal

compromise to uterine wall then both fetus and mare’s prognosis for survival is good.

Prognosis decreases if the uterus ruptured causing a peritonitis. If uterine strangulation occurred prognosis also decreases for fetus.

If blood flow or tissue oxygenation was compromised it also reduced prognosis for fetus.

No significant difference in mare survival was found between correction methods. Foals survival was best seen when using a flank incision

rather than ventral mid-line incision.

Uterine torsions are relatively uncommon, but complications can be life threatening for the mare and fetus