A normal ovary is about the size of a man’s thumb and hangs freely from the pelvic sidewall, nestled against the peritoneum (the smooth, shiny, Saran-wrap-like lining of the pelvis). Adhesions (scar tissue) can wreak havoc with this normal setting. Adhesions form as the body tries to heal itself from some type of irritation. Ovarian endometrioma cysts can be associated with adhesions which can bind the ovary to the sidewall, uterus, bowel or to the uterosacral ligaments behind the uterus. Other conditions which can result in adhesions are infection or surgery.

Adhesions come in two forms:

• stringy/filmy;
• confluent/dense.

Stringy/filmy adhesions are like cobwebs hanging between two surfaces. Those surfaces can still move somewhat normally and these adhesions are easy to cut or remove. Such adhesions don't always cause pain since organs may not be pulled out of their normal positions.

Confluent dense adhesions are the worst. Imagine if you glued two sheets of paper together and came back the next day to try to separate them. Even if you had surgical instruments and were very meticulous, by the time you were done, shreds of paper from one page would be stuck to the other, and vice versa. This is similar to what occurs with ovarian remnant syndrome: when an attempt is made to remove an ovary that is confluently and densely adherent to the uterus, bowel or pelvic sidewall, shreds of tissue from the surface of the ovary may remain behind. Even though these bits of tissue don’t have a normal blood supply, they can remain viable and even proliferate in size. In some cases, these bits of ovarian tissue may even ovulate or produce normal amounts of estrogen.

Ovarian remnant syndrome can cause pain in two ways (although there may be many cases of this syndrome which don’t cause pain and remain quietly undiagnosed). Imagine if you put a deflated basketball under a sheet on your bed and then inflated it: the increasing size of the ball would pull on the sheet in all directions. This is what happens when the ovarian remnant has cystic formation. The cyst can swell and pull on adhesions, causing pain.

The second way ovarian remnants can cause pain is by producing estrogen which can stimulate endometriosis that has not been removed (although it has been found that many lesions of endometriosis can produce aromatase enzyme which can result in the formation of estrogen in the endometriosis lesion itself, so endometriosis doesn’t necessarily care whether estrogen is being produced by the ovary or not).

When ovarian remnant syndrome causes pain, the patient will seek help from her gynecologist. Sometimes an ultrasound will show a cyst on the side where an ovary had been removed, but the ultrasound will not stop the pain. While birth control pills or other hormones that suppress ovarian function may have a theoretical chance of suppressing the function of an ovarian remnant, this doesn’t always work and such suppression can’t be continued forever. For this reason, surgery plays the major role in diagnosing and treating ovarian remnant syndrome.

The surgical treatment of ovarian remnant syndrome is simple at face value: all remnants of ovarian tissue need to be removed. The surgical dissection to remove ovarian remnants needs to go around and underneath all the ovarian tissue. This can be done laparoscopically in most cases. There is some danger of injury to other organs that may be involved by scar tissue, but careful dissection will help avoid this. One of the main “dangers” of surgery is that the same type of scar tissue that led to the development of ovarian remnant syndrome in the first place may lead to its persistence if bits of the ovarian remnant remain behind. Fortunately this is rare.

One question that comes up is “How can ovarian remnant syndrome be prevented?” This is an important question, and the answer relates to how the ovary was removed initially. If a laparotomy is done, the surgeon may simply reach in with the hand and peel the ovary off of the pelvic sidewall. While most of the volume of the ovary may have been removed, the possibility exists that little bits of ovarian tissue may remain behind on peritoneal surfaces, yet not be obvious to the surgeon because of the raw surfaces left after such a maneuver.

When an ovary is densely and confluently adherent to the peritoneum, the best technique would be retroperitoneal dissection. This means that the surgeon doesn’t try to dissect the ovary off of the peritoneum, but instead goes behind the peritoneum and dissects the peritoneum (with the adherent ovary still attached) off of the pelvic sidewall. The blood supply can then be interrupted and the ovary (with the peritoneum still attached) removed. Many surgeons don’t feel comfortable doing retroperitoneal dissection because it brings them close to the ureter (the tube carrying urine from the kidney down to the bladder) and to large blood vessels.

Surgical treatment of ovarian remnant syndrome is usually successful in the hands of an experienced surgeon.

Reference: Rana N, Rotman C, Hasson HM, Redwine DB, Dmowski WP. Ovarian remnant syndrome after laparoscopic hysterectomy and bilateral salpingo-oophorectomy for severe pelvic endometriosis. J Am Assoc Gynecol Laparosc 1996; 3:423-6.