Endoscopy began in 1805 with Bozzini (1), but it was Pantaleoni (2) who, in 1869, performed the first hysteroscopy, not only diagnosing an endometrial polyp with the aid of an endoscope, but cauterizing it with silver nitrate. A second generation of endoscopes was developed by Nitze (3) in 1879 who constructed a cystoscope with a lens system and a light source inside the endoscopic tube. With this innovation, vision was clearer, lighting more intense and the field of vision wider.
In spite of these early attempts, hysteroscopy was more a curiosity than a truly useful technique until the 1970s when technical improvements in lenses and distension media resolved some of the difficulties that had prevented its widespread use before that time. It was Hamou (4) who revolutionized the field of hysteroscopy with new, improved visual optics and instruments of fine diameter ( 4 mm). Improved optics, simpler techniques and the ability to perform the examination in the outpatient clinic without anaesthesia or cervical dilatation have further popularised hysteroscopy in the 1980s and 90s (5,6). Failure rates due to either cervical stenosis or pain can be as low as 3% (5,6). The acccuracy of diagnostic hysteroscopy in detecting uterine anomalies is recognized by most experts in the field today(7-9).
As interest in hysteroscopy grows as a consequence of these advances, there is an urgent need to introduce the technique more widely into routine gynaecological practice.
The remarkable progress made and the relative simplicity of the technique have widened the indications for hysteroscopy. Today diagnostic hysteroscopy can be considered the optimal method of assessing all cases where visualizing the cervical canal, uterine cavity and tubal ostea will improve diagnostic accuracy and guide therapeutic management. It is in the field of improved diagnosis that hysteroscopy has made the most significant progress, mainly because the ability to use fine diameter instruments makes it feasible to avoid both anaesthesia and cervical dilatation. The procedure may therefore be performed in an outpatient setting without the need for hospitalization.
While hysterosalpingography (HSG) and endometrial biopsy are important and well established techniques in the investigation of infertility, only hysteroscopy permits an accurate assessment of the of the genital tract in infertile women. Direct visualization of the uterine cavity and tubal ostia coupled with targeted endometrial biopsy provide more specific information which may clarify the cause of the infertility. HSG has limitations as a diagnostic tool. Dubious or erroneous results have been reported in as many as 40% of the cases when HSG is compared with hysteroscopy and laparoscopy (10). The need for hysteroscopy becomes clear when filling defects are seen on HSG (11). A study conducted in 1983 showed that the uterine cavity as seen at hysteroscopy was normal in 45% of the women in whom a prior HSG had suggested a uterine anomaly (12).
Hysteroscopy is recommended for the diagnosis and treatment of intrauterine adhesions, to assess the anatomical and functional condition of the uterotubal ostia, to determine and guide post surgical management of metroplasty and salpingoplasty, to identify and treat suspected intrauterine pathology such as submucous myomas, endometrial polyps and hyperplasia and to assess the status of the uterine cavity in cases of repeated abortion.
Hysteroscopy aids both the diagnosis and management of intrauterine adhesions. It allows a panoramic as well as a close-up view with magnification. At x20 magnification, three different histological types of adhesions may be seen: endometrial, myofibrous, and connective (13,14). Endometrial adhesions are usually fragile, soft, and whitish in appearence and are easily divided. Myofibrous adhesions on the other hand, require a more aggressive technique. Connective tissue adhesions, which are greyish and dense, are the most difficult to divide (15). Successful management can be achieved in most cases. In our experience a normal menstrual flow followed in 86.7% of the cases with a pregnancy rate of 44.4% (16).
Hysteroscopy is the best means of studying and evaluating the anatomy and function of the uterotubal ostium. HSG may give false results because pressure of distension medium in the uterine cavity and intramural portion of the fallopian tube may provoke contraction of the sphincteric muscle. Hysteroscopy allows the observation of the ostium under almost normal conditions. Falloposcopy, which may be controlled with or without hysteroscopy allows examination of the tubal lumen as far as teh isthmo-ampullary junction and, occasionally, as far as the fimbrial opening (17,18). This is less invasive and traumatic than laparoscopic salpingoscopy or intraoperative microbiopsy (19,20).
Intra-uterine pathology, including submucous myomas, polyps, and hyperplasia, may occur in a relatively high percentage of asymptomatic, infertile patients (21-23). These conditions can be easily identified and classified through hysteroscopy.
Endometrial biopsy is useful in the cases of polyps or hyperplasia. Although the role of endometrial pathology in infertility is debatable, the presence of gross intracavitary pathology can easily interfere with the process of nidation. In our experience, the percentage of asymptomatic submucous myomas in infertile patients is 5.2% (24). Additional pathology which can interfere with embryo implantation and development are uterine malformations, particularly a septate uterus, although uterine malformations are usually associated with pregnancy wastage, not infertility. Hysteroscopy and laparoscopy allow precise classification and consequently appropriate treatment of uterine malformations. When facing the problem of recurrent abortion, visualization of the uterine cavity becomes indispensable for a correct diagnosis, and forms the basis for an appropriate therapy (25).
2. Abnormal Uterine Bleeding (AUB)
One third of all gynaecologic consultations are because of AUB and this constitutes the second indication for hysteroscopy. This proportion rises to more that two thirds when the peri- and postmenopausal age groups are considered (26). Excessive mestrual blood loss is a strong indication for exploring the uterine cavity and determining the underlying pathology. The only other method available in such cases is Dilatation and Curettage (D&C). D&C provides a histological diagnosis, but it often requires general anesthesia and, in many hospitals an overnight stay. The main drawback of D&C is that it is a blind procedure that may not identify focal lesions. The correct diagnosis may be missed even in the presence of endometrial polyps, myomas and neoplasia. Published information places diagnostic failures of D&C at between 10% and 25% (27,28). In our own experience, hysteroscopy with an endometrial biopsy is the procedure of choice in patients with abnormal uterine bleeding (29,30). Biopsy is especially important if hyperplasia, polyps or endometrial cancer are suspected. The reliability of hysteroscopy approaches 100% in endometrial neoplasia, and has been estimated at 87.5% in "high risk hyperplasia" and 65.2% in "low risk hyperplasia" (31). Over 50% of patients over 45 years with AUB have a normal endometrium.
The diagnosis cannot rely exclusively on hysteroscopy, but its diagnostic accuracy is greater than any other technique in use today.
3. Endometrial Hyperplasia and Cancer
The third area in which hysteroscopy can provide valuable information is in the prevention and early diagnosis of neoplastic lesions of the endometrium. Early diagnosis of endometrial adenocarcinoma may be difficult in pre-menopausal women, since this type of neoplasm may be asymptomatic for a long period. Although D&C and endometrial biopsy are also reliable for the diagnosis of endometrial neoplasia, hysteroscopy has the advantage of permitting a targeted biopsy in the event of localized lesions, reducing the possibility of false negatives. In addition, it permits proper classification of the extent and degree of hyperplasia.
Although there is no specific appearance for each histological type of endometrial hyperplasia, endoscopic classifications have been developed that can be applied clinically (32). The hysteroscopic appearance of low risk endometrial hyperplasia(EH)includes an increase in the thickness of the endometrium, its dyshomogeneous regeneration, increased vascularization and the presence of ciliated images, cystic dilatation, increased bleeding, polypoid formation, necrotic zones and the concentration and irregular arrangement of the glandular openings. If one or more of these elements are found, hyperplasia must be suspected. Guided endometrial biopsy can then be performed.
The hysteroscopic appearance of high risk endometrial hyperplasia or endometrial intraepithelial neoplasia (EIN) clearly defines these pre-neoplastic and neoplastic lesions: Polyps are often present and abnormal vascularization produces an arborescent appearance which surrounds groups of glandular orifices. The architecture and organization of the uterine cavity is altered. The endoscopist can easily confirm the hysteroscopic suspicion with endometrial sampling of specific areas.
In its initial stages, endometrial cancer shows a papillary
appearance with irregular polylobate excrescences which are friable and
partly necrotic or haemorrhagic. Vascularization is irregular and anarchic.
Often there is a clear dividing line between cancerous and normal endometrium.
Neoplastic lesions can be focal and localized at the tubal cornua.
In order to check the diagnostic accuracy of hysteroscopy, we have compared visual images to histologic results (34) and found a good correlation in 87% of the cases of EH, in 92% of the cases of adenomatous hyperplasia with atypia or EIN, and in 94% of adenocarcinomas. Considering that AUB, either per se, or in association with risk factors for endometrial adenocarcinoma such as obesity, diabetes, hypertension or the unopposed use of estrogens in peri-and post-menopausal patients, leads to a suspicion of endometrial cancer, it should not be surprising that hysteroscopy must be considered the examination of choice in these patients.
Most of the classic contraindications of diagnostic hysteroscopy, such as the presence of an active pelvic infection or cervical cancer, are not considered any more as absolute, but rather as relative. In these cases the examination can be performed, but the surgeon must observe adequate precautions.The potential spread of an infection caused by intrauterine manipulation and the pressure of the distending medium may increase the risk of spreading infection so prophylactic antibiotics should be given. Hysteroscopy can be performed without any major risk of spreading malignant cells in patients with invasive cervical carcinoma. However, hysteroscopy in the presence of invasive cervical cancer has no practical value if we exclude the differential diagnosis of a primitive adenocarcinoma of the endocervix, a very rare form of cancer.
Special care is required in discussing hysteroscopy in early pregnancy. This can be performed without affecting the pregnancy, although the indications are few. They include the removal of a "lost IUCD" to avoid the risk of a septic abortion.
The patient should be examined and a speculum introduced. A tenaculum is placed on the anterior lip of the cervix for traction. At this time local anesthesia can be used, if appropriate, by injecting a few ml of carbocaine 2% into the cervix. The flow rate of CO2 is set at 60 ml/min. The hysteroscope is gently introduced in the cervical canal and advanced under visual control into the uterine cavity. The ectocervix and vaginal fornix, cervical canal and uterine cavity may be explored.
During examination of the ectocervix low magnification (x1, x20) provides results that are comparable with those obtained by colposcopy, although traditional colposcopy presents clear advantages because the colposcope allows a more accurate observation of fine details which are so crucial in cervical pathology. The field of vision of the colposcope is wider and is not deformed by the 30 degree angle view afforded by the hysteroscope. Microcolposcopic contact vision, with x60 and x150 magnifications shows the superficial layers of the epithelium with a field depth of about 80 micron and provides a microscopic view of the nucleus and cytoplasm. Such high magnification requires prior staining with Lugol and Watermann blue solution.
Low magnification gives a panoramic view and can provide important information on the integrity of the anatomical structure of the cervical canal. The application of a few millilitres of 2% acetic acid may often show the squamous-columnar junction (SCJ), when this has risen inside the cervical canal. The SCJ is always visible and clearly defined after vital staining with Watermann blue solution using contact viewing and magnifications of x60 or x150 It is possible to judge exactly how far the instrument has advanced into the cervical canal.
During the examination of the uterine cavity simple panoramic viewing at x1 or x20 magnification has proved extremely useful in identifying all types of endometrial pathology (5,6). Microscopic contact viewing requires some form of anaesthesia because of the relatively long time needed for the examination and the consequent discomfort to the patient and should be reserved for cases where its use is specifically indicated. Problems such as pain, bleeding obscuring the endoscopic vision, or poor distension of the uterine cavity are directly related to the experience of the endoscopist (6).
Diagnostic hysteroscopy is a safe procedure. Complications mainly occur when inappropriate instruments or techniques are used.
The prevalence of vagal reaction depends on the ability of the endoscopist and on the diameter of the scope. It can be prevented with the administration of 0.5 ml of atropine 20 minutes prior to commencing the procedure. Atropine should not be given if the patient suffers from cardiocirculatory problems.
The most frequent complications seen during hysteroscopy are the result of over distension of the uterine cavity. The uterus can be adequately distended with a pressure of 60 to 80 mm Hg of carbon dioxide. Automatic "hysteroflators" keep of CO2 flow under 80 ml/min and maintain an intrauterine pressure less than 100 mm Hg and make the procedure very safe. Gaseous intravasation usually occurs only at CO2 pressures above 400 mm Hg. When this occurs there is a decrease in PO2 and an increase in PCO2.
Complications can also occur when using Dextran-70 ("Hyskon"). They include pulmonary edema, anaphylactic reactions and coagulopathy consequent to intravasation. Liquid intravasation can provoke pulmonary edema also with low viscosity fluids such as saline solution and Ringer’s lactate but this can be easily managed by intravenous diuretics. Saline and Ringer’s lactate cannot be used with electrosurgery because they contain electrolytes. The risk of complications increases with the duration of the intervention and when intrauterine manipulations are performed. Loffer (38) reported an incidence of intravasation of 1.1% when performing hysteroscopic myomectomy but did not report an incidence for diagnostic hysteroscopy.
The golden rule to avoid intravasation with any liquid distension media is to measure the difference between the quantity of liquid infused into the patient and the quantity reaspirated and always maintain the deficit at under 1 liter.
Uterine perforation is a rare event. It occurs in 4 out of 1000 cases of diagnostic hysteroscopy. Perforation usually occurs in difficult cases during dilatation of the cervix (39). Perforation occurs more frequently at the level of the fundus without significant bleeding. When perforation occurs laparoscopy should be performed and antibiotics and oxytocin administered for at least two days. Salat Baroux et al (39) have reported an incidence of 0.2% of infection in over 4000 diagnostic hysteroscopies.
Truly useful techniques and procedures frequently evolve slowly in medicine. They are usually developed to answer a specific need. For this reason, their evolution depends on many factors.
While it may be true that the first hysteroscopies date from the beginning of the 20th century, enthusiasm for its use has only recently gained momentum and has now begun to expand exponentially. It should not be surprising that the development of practical hysteroscopic techniques is proceeding parallel to the development of highly sophisticated endoscopic methods of visualizing other body cavities, as one technique feeds and reinforces the others. In spite of this, there is still a reluctance to incorporate this procedure into routine office gynecologic practice. Yet, the potential of hysteroscopy ranging from diagnosis of abnormal uterine uterine bleeding to the microscopic confirmation of cervical precancerous lesions permits us to predict that it will play an increasing role in our ability to diagnose diseases of the female reproductive tract quickly and accurately.
Hysteroscopy also offers advantages in the diagnosis and management of infertility and repeated abortion. The use of diagnostic hysteroscopy in the management of abnormal uterine bleeding may, in many instances, replace procedures such as D&C. The magnifying power of the microhysteroscope and its ability to penetrate the cervical canal to regions inaccessible to the colposcope suggest a very real role in the assessment of precancerous and cancerous lesions of the endometrium.
Hysteroscopy is no longer a "procedure looking for an indication".
Edited by Aldo Campana,