The colposcope, whether attached to the examining table or mounted on a free standing mobile base, is best placed to the left of the examiner in order to provide ample room for those procedures most often performed with the right hand. Accordingly, left handed physicians should locate their colposcopes on the right. In either case, the colposcope, positioned on a system of pivotal arms, can be expediently centered for the examination.
Some colposcopes are fastened to the top of a pole which is attached to a flat stand. Such stands are often somewhat unsteady, and the colposcopist frequently must place his feet on the base of the stand to ensure sturdiness. A self retaining bivalve speculum is needed for adequate visualization of the cervix and the vagina. A variety of sizes should be available. A speculum longer than 10 cm is seldom required, if use, it may be ejected from the vagina as a result of its unevenly distributed weight.
The Pederson and the virginal specula are useful for the examination of sexually inactive women. These specula are particularly convenient for evaluating adolescents who were exposed in utero diethylstilbestrol. Since reflective highlights from conventional stainless steel instruments will distort colpophotographs, it is recommended that these specula be purchased in matte variety stainless steel or with Teflon coating.
Colposcopic examination may be accomplished by the successful completion of the following three steps. First is the inspection of the unprepared cervix and vagina, and, when indicated, the vulva. Second is the inspection through the green filter. Third is the inspection following application of the acetic acid three percent solutions. At all times throughout the colposcopic examination, the examiner should look for characteristics of and alterations in epithelial color and opacity, surface contour, clarity of demarcation of tissue patterns, vascular configuration, and intercapillary distance.
A warm vaginal speculum without lubricant should be introduced slowly into the vagina. The blades of the speculum must be partially separated soon after entry into the vagina to avoid traumatizing the cervix as it is exposed. If necessary, a Papanicolaou smear can be taken concurrently with the colposcopic examination. However, this procedure may initiate bleeding and obliterate features of colposcopic interest. In general, cytologic smears are best taken from the cervix and from the endocervical canal at a separate examination prior to colposcopy. The vaginal speculum should be held by one hand and manipulated to place the cervix at the right angles to the incident light. The other hand should direct the colposcope toward the cervix until focal length is obtained for optimal resolution. Mucus may be removed gently from the cervix with either a dry gauze or one soaked in normal saline. The latter tends to produce less contact bleeding. The vagina and cervix should be inspected through the colposcope using initially 5x to 16x magnification. For this examination, the cervical and the vaginal surfaces should be moistened with normal saline. A dry epithelial surface is not transparent and gives a poor view of vascular patterns.
The purpose of the colposcopic examination of saline washed tissue is to delineate gross lesions and observe vascular detail. The unprepared epithelium provides no useful information regarding tissue properties such as color or opacity. Use of the green filter provides the best colposcopic impression of vascular patterns. The green filter absorbs red from the color spectrum; this causes blood vessels to stand out as black structures against a background of white or translucent epithelium.
Acetic acid three percent solution in water was used first by Hinselmann in 1925. It offers the sharpest contrast between foci of normal and abnormal tissue. For reasons which remain obscure, acetic acid solution shrinks blood vessels, dissolves mucus, and causes individual cells to swell. Transparency of epithelium is greatly reduced and the grape like structure of columnar tissue enhanced. A change in atypical forms of epithelium occurs. Dysplastic and neoplastic epithelia take on a well demarcated whitish hue. Such epithelia, prior to application of acetic acid, show no distribution in color from normal tissue. A three percent solution of acetic acid is generally used for colposcopic examination, two, four percent or five percent dilutions of acetic acid are also acceptable, although less preferable. The weaker dilution requires a longer waiting to allow for the appearance of epithelial lesions. The stronger solutions delineate lesions more rapidly but are quite irritating to mucous membranes, especially after repeated applications.
Observable changes in epithelial surfaces are transient ones. They develop within one minute after application of three percent acetic acid and fade in two to three minutes. They can be restored with additional acetic acid, and several applications may be required during the course of a single examination. Inspection of unprepared cervix and vagina should be followed immediately by scrutiny of the same areas treated with acetic acid. Gauze swabs or cotton wool pledgets saturated with acetic acid can be used to paint the entire surface of the cervix and adjacent vagina. A liberal application of acetic acid is required. Fine cotton tipped applicators moistened with acetic acid should be used to paint the epithelium of the endocervical canal. Tissue treated with acetic acid should be inspected under 5x to 16x magnification. If abnormal vessels are seen, better contrast is achieved by using the green filter and by increasing magnification to 25x or even 40x.
Unlike saline washing, acetic acid washing permits evaluation of changes in tissue color, opacity, and surface contour. Some investigators have suggested that vascular architecture is best observed with saline washing. However, acetic application also delineates vascular patterns as well. Repeated application of acetic acid sometimes results in substantial dilatation of blood vessels. Abnormal blood vessels which appear following several applications of acetic acid may be iatrogenic. Many colposcopists initially advised that iodine staining of vagina and cervical mucosa marks the end point of every colposcopic examination. Ordinarily, native squamous epithelium, high in glycogen content, stains deep mahogany brown when iodine is applied to it. Such an area is referred as Schiller negative or iodine positive. Columnar epithelium, undifferentiated metaplastic epithelium, and abnormal epithelium, in general, are nonglycogenated and therefore do not stain with iodine.
Many colposcopists now agree that the iodine test adds little or nothing to the evaluation of the colposcopic picture. It destroys all minute details necessary for precise diagnosis. It interferes with localization of the most abnormal areas within a lesion requiring biopsy. Moreover, iodine staining constitutes a nonspecific test. Some malignant tissue may contain glycogen and take up stain. Alternatively, many benign areas metaplastic epithelium, columnar epithelium, inflammatory changes, vaginal adenosis, all may produce iodine negative areas. Iodine solutions, if they are used, must be aquaeous. An alcohol-base causes destruction of tissue which hinders the histologic evaluation of biopsies.
Lugol solution is more reliable for colposcopic examination than Schiller solution. The effect of the latter is countered by the presence of acetic acid. It is important to keep in mind, however, that all staining techniques fail to distinguish the relative, subtle degrees of atypicality which are essential to the concept of the directed biopsy.
Colposcopy establishes the location and extent of foci of abnormal epithelium. Colposcopic features such as color, opacity, vascular pattern, and surface contour are reliable indicators of the degree of histologic atypia. Tissue sampling of specific abnormal areas can be performed easily under colposcopic guidance. A biopsy taken in the area greatest colposcopic abnormality will yield the diagnostic information necessary for implementation of appropriate therapy. Frequently biopsy during the early part of training in colposcopy is a prerequisite to achieving a clear understanding of the underlying tissue structure. Multiple biopsies, even of seemingly normal areas, properly labeled, provide the best form of instruction by which each colposcopist learns to correlate specific colposcopic pictures with benign, precancerous, or malignant histologic patterns. Carefully excised, well preserved, and oriented, rapidly fixed specimens afford the best opportunity for accurate diagnosis.
A variety of instruments may be used for punching out small sections of epithelium. The common biopsy instruments include the eppendorfer, kevorkian, tischler, and younge forceps. The eppendorfer forceps takes small, relatively superficial biopsies, whereas the tischler forceps is designed to extract somewhat larger and deeper tissue sections. The kevorkian and younge forceps have serrations on the posterior blade which aid in stabilizing an area requiring biopsy. Care should be taken so that the cutting edges of the biopsy forceps are not dulled by misuse. Forceps should not be autoclaved; they should be soaked in cidex or sterilized with gas.
Sometimes the tissue of the cervix or vagina is so firm or taut that it cannot be grasped with biopsy forceps. A tonsil or iris hook can be used to tent the epithelium in order to facilitate extraction of a punch biopsy. The Irish hook also helps move the cervix away to examine the vaginal fornices. Patients with positive cytologic smears require careful inspection of the vagina fornices before any definitive treatment ia carried out. It is advised to obtain biopsy instruments of 15 m length when colposcopes with fixed working distances of approximately 20 cm are used. Ideally, biopsies should be obtained under colposcopic observation. If the length of biopsy instrument is greater than 15 cm, the colposcope may need to be removed at the time of biopsy and repositioned to check that a biopsy was removed from the specific area in question. The punch biopsy is used primarily for the purposes of diagnosis. When taken from the vagina or cervix, such biopsies require no anesthesia. Punch biopsies may serve as a form of treatment when lesions are small and all boarders well defined. Such lesions can be eradicated locally by one or small bites. Biopsies should be taken to a depth sufficient to obtain enough stroma for differential diagnosis. The epithelium must be cut at right angles to the surface in order to avoid producing tangential sections.
All biopsy forceps should possess openings in the jaws to receive the specimens rather than to compress them. Any crushing of epithelium will cause distortion of the tissue architecture. Several punch biopsies maybe required from single patient biopsies at the periphery of the cervix and on the posterior lip should be obtained prior to those at the external os or on the anterior lip. Biopsies from the posterior vaginal wall should be taken before those from the lateral or anterior vaginal surfaces. This system prevents blood from earlier biopsy site from hampering vision needed for succeeding biopsies. If bleeding occurs, homeostasis can be achieved by applying Monsel’s solution or ferric subsulfate followed by the gentle pressure of vaginal tampon. In rare instances, sutures or clips may be required. Except in cases where the entire area of colposcopic atypicality has been excised and the diagnosis well established, the use of hot cautery at the base of the biopsy site to alleviate bleeding is clearly contraindicated. Cautery destroys surrounding tissue and renders it unsuitable for later histologic or colposcopic examination.
Excisional biopsy and endocervical curettage can be performed under colposcopic observation. Excisional biopsy is especially suited to diagnosis of vulvar lesions. It is also useful for treatment of abnormal colposcopic areas on the vagina and cervix when these areas are well demarcated and entirely visible. The cervical conization or endocervical biopsy provides more reliable diagnostic information than endocervical curettage. Endocervical biopsy can be accomplished with the bronchial biting forceps whose cutting edge is at right angles to the instrument handle. A portion of endocervical tissue with stroma can sometimes be included in a cervical biopsy if the large forceps are used.
Precise recording data is an essential element of good colposcopic technique. Sequential photographic studies are desirable. They permit the most accurate analysis of tissue changes related time. A systematic method such s the Odell diagram for succinct, verbal recording of data is mandatory. Hammond graph affords another simple way of keeping records of colposcopic findings and biopsy sites. It is composed of a series of concentric circles divided into multiple sections. The diagram is available on a rubber stamp and is readily affixed to the medical record. When video tapes or photographic slides are used to demonstrate precise colposcopic appearances, simple hand drawings along with a clear explanation and list of biopsy sites is probably sufficient for the office or clinic medical record.