Endometriosis is a relatively common problem in women of reproductive age. It may be found incidentally at laparotomy or may cause symptoms or signs which cause a laparotomy to be performed. An incidental finding of endometriosis can cause a dilemma for the surgeon since open surgery is not usually the treatment of choice unless a radical approach is intended.

Endometriosis is the extrauterine presence of glands and stroma which histologically resemble endometrium. The origin of this tissue remains uncertain; many theories have been proposed. The consequences of endometriosis depends on the site: the most common sites are the ovaries, the pelvic peritoneal surfaces, and the posterior aspect of the uterus; other sites such as bladder and bowel are occasionally affected.

The endometriotic implants cause localized haemorrhage which leads to the classical appearance of either ‘chocolate cysts’ or bluish-black nodules which may be associated with a local inflammatory reaction, fibrosis, and adhesions. These are now known to represent only part of the spectrum of peritoneal endometriosis. Biopsy studies indicate that much peritoneal endometriosis is not bluish-black in appearance: small haemorrhagic and non-haemorrhagic lesions represent what may be stages in the progression of the disease. These less classical appearances have been correlated with the rate of biopsy confirmation of the diagnosis. There is a close correlation for white opacified peritoneum (81 per cent), red flame-like lesions (81 per cent), and glandular lesions resembling endometrium (67 per cent), and reasonable correlations for subovarian adhesions (50 per cent), yellow-brown patches (47 per cent), and circular peritoneal defects (45 per cent). The range of peritoneal appearances is illustrated in Fig. 1 1453,1454,1455.

The problem of diagnosis has been further compounded by the evidence that biopsy samples from visually normal peritoneum often contains microscopically detectable endometrial tissue.

The inflammation associated with endometriotic implants is probably due to the production of substances such as prostanoids and cytokines. The peritoneal reaction can be severe, causing the formation of extensive adhesions, particularly after surgery. In such women a second laparotomy may reveal densely adherent organs, matted loops of bowel, and pelvic organs making it difficult to distinguish individual structures (Fig. 2) 1456.

Endometriosis detected at a general surgical laparotomy tends to be one of the more severe forms of pelvic disease or intestinal endometriosis, since the more subtle appearances are usually restricted to the pelvis and seen only on close inspection with the laparoscope.

The characteristic symptom of endometriosis is menstrual or immediately premenstrual pain. This pain may reflect stretching of tissues by a local ‘menstruation’, a local effect of prostaglandins, or might relate to tissue damage and adhesion formation. There is wide variation in the extent of distress, and this correlates poorly with the extent of observed disease. Many women with endometriosis are asymptomatic: some of these have severe disease discovered either after the incidental detection of an ovarian cyst or during investigation of infertility.

Deep dyspareunia can occur, probably resulting from pressure on affected organs such as a fixed retroverted uterus, affected ovaries, uterosacral ligaments, and the rectovaginal septum, but these areas can be affected without such symptoms. In one series of more than 700 women only one in four of those who were sexually active and had disease affecting the pouch of Douglas (cul-de-sac) reported dyspareunia.

The most likely cause of endometriosis presenting as an acute abdomen is rupture of an ovarian ‘chocolate cyst’. This is not a common complication but is more likely than torsion, since such cysts tend to be adherent locally. A less common acute abdominal presentation is a result of bowel obstruction due to intestinal endometriosis.

Clinical examination may increase suspicion of the presence of pelvic endometriosis. An ovarian mass or masses, thickening or tenderness in the uterosacral or pouch of Douglas areas, and fixed uterine retroversion are all features which should warn the surgeon of an increased risk of endometriosis, particularly if accompanied by characteristic symptoms. Non-invasive investigative methods such as serum markers, ultrasonic or CAT scanning, and NMR imaging have not proved sufficiently specific to have found a place in routine diagnosis. Detection of the antigen CA125 by immunoscintigraphy may allow more specific detection of endometriosis.

When endometriosis is suspected by a gynaecologist the standard approach is to perform a diagnostic laparoscopy. This may be followed by medical therapy or the lesions may be treated using laser or other techniques at the time of the assessment. The treatment required may well be less radical than the surgeon is tempted to carry out. The decision over treatment is particularly difficult if the surgeon has not routinely taken a reproductive history, since the woman's fertility needs will be relevant to therapy.

If there is any reasonable possibility that laparotomy will reveal severe endometriosis, the surgeon should discuss with the patient whether she would accept hysterectomy or even hysterectomy and bilateral oophorectomy. Such a step is rarely undertaken at the first diagnosis of endometriosis and few women would find such radical surgery acceptable without careful discussion of the consequences.

The different findings at laparotomy present the surgeon with different considerations. Factors to be weighed in decision making include whether the woman is infertile, whether she is symptomatic, and what therapy would have been chosen for that set of circumstances if they had been detected in advance by laparoscopy.

The likely findings at laparotomy can be classified into broad categories as in ovarian cysts, adhesive disease, intestinal lesions, and disease limited to the pelvis.

A laparotomy may be performed following rupture of an ovarian cyst. Endometriotic ‘chocolate cysts’ can be several centimetres in diameter, and their rupture releases viscous inspissated blood into the peritoneal cavity. Resection of such cysts is appropriate since medical treatment tends to have little impact. Most gynaecologists would perform a laparotomy; the cyst should be removed intact if possible. If it ruptures, the lining should be removed. The ovary can then be reconstituted. Those expert in pelviscopic surgery may attempt cystectomy via the laparoscope.

If the woman does not intend to have children in the future, it is usually preferable to remove the whole ovary, having ensured that the other ovary is healthy. If bilateral cysts are often found it is important to preserve some ovarian tissue.

Until relatively recently it was considered inappropriate to remove both ovaries and leave the uterus intact. This approach results in the need for hormone replacement therapy, which then induces menstruation and the need for progestogen therapy with its potential side-effects. This argument still applies if there is no wish for a future pregnancy. If pregnancy may be desired the retention of the uterus without the ovaries can be considered if the woman is prepared to undergo a pregnancy by ovum donation, where she is not the genetic mother.

Pelvic adhesions are common in association with endometriosis (Fig. 1(e–f)) 1454, and may cause extensive matting of tissue including pelvic organs and/or bowel ( Figs. 1(f) 1454 and 2 1456). These adhesions should be separated, taking care to minimize tissue handling, drying of tissues, and haemorrhage (see Section 30.15 211). The extent to which adhesions will reform is uncertain, and subsequent examination may reveal that little has been achieved in the long term. There is a good case for adhesolysis to be performed via the laparoscope when possible since laparoscopic techniques are thought to cause fewer subsequent adhesions. The carbon dioxide laser is particularly useful for adhesolysis, since the heat generated by the laser beam is dissipated within 0.1 mm; thus with experience it can be used to separate bowel from other structures.

Surgeons are occasionally confronted at laparotomy by endometriosis affecting either the superficial serosa or the muscular layer of the bowel. Most series reporting this have been small. A recent larger series of 127 cases, which excluded superficial lesions, reported sigmoid and rectal involvement in 52 per cent, and appendicular, ileal, and caecal disease in 22 per cent, 17 per cent, and 5 per cent, respectively. One-quarter of patients with disease of the sigmoid and rectum had rectovaginal septum involvement, and ileal disease always involved the last 50 cm of the ileum. Other sites are rarely affected.

Analyses of women seen by surgeons and gynaecologists reveals different viewpoints and patient populations between the two specialities (Table 1) 411.

Surgeons are more likely to resect bowel and to perform castration but are less consistent in checking the pelvic organs. They are also less likely to perform selective excision of genital lesions and less likely to use hormonal therapy.

A perimenstrual barium enema with double contrast can be valuable if there is clinical suspicion of intestinal endometriosis. This will reveal features such as filling defects, stricture, and external compression. Sigmoidoscopy can also be useful, revealing the endometriotic lesions and permitting biopsy.

At the time of laparotomy excision of bowel lesions thought to be endometriotic is justified. There is a fairly high recurrence rate for bowel symptoms after medical treatment, as well as a risk of subsequent obstruction or malignant transformation of intestinal endometriosis.

The management of endometriosis limited to the reproductive organs and pelvic peritoneum, but with no significant ovarian cysts should take the form of assessment of the extent of disease, symptoms, and the woman's fertility requirements.

The first step should be to score the endometriosis as indicated by the revised American Fertility Society Classification Figs. 3 and 4 1457,1458,1459). This scoring system was recently reviewed in detail and aims to facilitate grading of severity and comparability of results in treatment studies. Treatment options can then be considered.

If the woman is thought to have endometriosis-related pain the lesions should be ablated using laser, endocoagulation, or electrodiathermy. Any surgeon attempting such ablation must be aware that some peritoneal lesions overlie sensitive structures such as the ureter. The most likely sites for ablation will be the surface of the uterus, the ovaries, and the pelvic peritoneum.

If the woman is not thought to have pain relating to endometriosis then it is still appropriate to ablate moderate or severe lesions. When the disease is minimal or mild the case for intervention is less clear, particularly in asymptomatic women who are being investigated for infertility. There is no good evidence that surgical or medical treatment improves on pregnancy rates achieved in untreated women with minimal or mild disease.

The extent of surgical intervention must be influenced by desired fertility. Ovaries affected only by surface lesions should not be removed. Lesions can be ablated or treated medically, but unless significant ovarian cysts are present the ovary should not be damaged further since it is of major importance for future pregnancy, whether achieved naturally or by assisted conception.

Since it is difficult to ablate all lesions surgically there is a logical case for a period of hormone treatment, usually 6 months. This might be omitted if there is a desire to conceive quickly. There are many advocates of postoperative medical therapy but as yet there is no evidence from prospective studies comparing that approach with surgery alone.

If medical therapy is required the best alternatives appear to be danazol or the gonadropin-releasing hormone agonists. These alternatives are equally effective in the treatment of endometriosis but have different side-effects. Progestogens are thought to be less effective, but may be better tolerated by some women.

Women who undergo bilateral oophorectomy should receive oestrogen replacement therapy to counter the increased risk of postmenopausal osteoporosis, myocardial infarction, and symptoms of the menopause.

Anxiety that oestrogen replacement might stimulate recurrence of endometriosis has some foundation, but the few published studies suggest that the risk of recurrence is low. The consequences of an untreated premature menopause are sufficiently severe for the risk of oestrogen replacement to be worth taking. The decision may be more difficult in patients with intestinal endometriosis since the one follow-up study in which all cases had bowel endometriosis reported an 18 per cent recurrence rate. It should be remembered, however, that endometriosis may recur, whatever therapy is used. Following conservative surgery the recurrence rate is reported at 3, 6, and 9 years as 10.5, 26.6, and 47.2 per cent respectively.

For many women the management of their endometriosis, if it is severe, can become a test of endurance. They suffer chronic pain and dyspareunia and can have recurrent episodes of disease which may eventually so exhaust medical and surgical options (including pelvic clearance) that there is little to offer except the services of a pain clinic.

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