Correction of an Incompetent Cervix By McDonald Operation

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Correction of an Incompetent Cervix by McDonald Operation

The McDonald operation is used in a pregnant patient with an incompetent cervix. It may be performed under local anesthesia with minimal irritation to the uterus. It should be performed as early in the pregnancy as possible and must be done prior to effacement and complete dilation of the cervix.

Rupture of the membranes, leading to the loss of the pregnancy, may be associated with the procedure. The suture must be cut prior to labor to prevent severe laceration of the cervix.

In the McDonald operation, a suture is strategically placed to give additional strength to the cervix and thereby prevent second-trimester abortion.

Physiologic Changes. By suturing the cervix, the products of gestation are held in the uterine cavity until the fetus is viable.

Points of Caution. Care must be taken not to lacerate the soft pregnant cervix with the instruments.

The suture must be placed near the internal cervical os, but care must be exercised not to enter the bladder with the suture anteriorly.

Technique

The patient, who may be given light sedation with Demerol and Valium, is placed in the dorsal lithotomy position. The vulva and vagina are prepped with a surgical soap solution, and the weighted posterior retractor is placed in the vagina to expose the cervix. An effort is made to place a minimum of retraction instruments upon the cervix; if a retraction instrument is needed, however, a wide-mouthed toothless instrument such as a sponge forceps is preferable to a single-toothed cervical tenaculum. A large, monofilament nonabsorbable suture, such as Prolene or nylon is selected. The first bite of the McDonald stitch is placed at the 12 o'clock position on the cervix at the junction of the vaginal mucosa and portio of the cervix at the level of the internal os.

Repeated pursestring sutures are placed in 4 or 6 bites around the cervix at the level of the internal os.

The pursestring suture is tied.

A cross section of the cervix reveals the way the McDonald suture closes the internal os. The suture must be cut prior to labor and delivery of the fetus.