Hysteroscopic equipment (hysteroscopes)

Expensive equipment is required to perform a hysteroscopy. Before starting to perform a hysteroscopy, the specialist must undergo special training in the use of equipment and medical manipulations. Endoscopes and endoscopic instruments are very fragile and require careful handling to avoid damage. Before starting work, the specialist must carefully inspect all equipment to identify possible malfunctions.

Currently, hysteroscopic equipment is produced by various companies, but the most widely used devices are those of Karl Storz (Germany) with the Hopkins and Hamou optical systems, Wolf (Germany) with the Lumina-Optic optical system, and Olympus (Japan). In recent years, Circon-Acmi (USA) hysteroscopes have appeared. There are rigid microhysteroscopes with a small diameter for outpatient hysteroscopy.

Hysteroscopes

The telescope is the main element of hysteroscopic equipment. Rigid telescopes with the "Hopkins" lens system are most often used.

The advantages of this design over a conventional optical system are better resolution, contrast, and clarity both at the periphery and in the center of the field of view. Various viewing angles (0, 12, 20, 25, 30, and 70°) allow most of the object to be viewed in one field of view. The use of a telescope with one or another viewing angle depends on the surgeon's preferences.

For simple diagnostic hysteroscopy, optical tubes with a 30° viewing angle are more convenient, as they allow easier orientation in the uterine cavity. For surgical interventions, it is also preferable to use a telescope with a 30° viewing angle.

The Hopkins lens system takes up less space, which allows for a maximum reduction in the diameter of instruments (telescope diameter from 2.4 to 4 mm), making their insertion safer, less painful and easier to control.

A simple panoramic telescope magnifies images 3.5 times only at close range, and there is no magnification in panoramic viewing. Although the telescopes are protected by steel tubes, they must be handled with extreme care. Even a slight shift of the lenses inside the steel housing will damage the telescope.

Microcolpohysteroscopes. In 1979, Hamou combined a telescope and a compound microscope. The resulting optical system allowed both panoramic examination of the uterine cavity and microscopic examination of cellular architecture in vivo, using the contact method after intravital cell staining. The device was called the Hamou microcolpohysteroscope.

Currently, this type of hysteroscope is manufactured by the company "Karl Storz" (Germany). There are two versions of microcolpohysteroscopes - I and II.

The Hamou I microcolpohysteroscope has a diameter of 4 mm and a length of 25 cm, 2 eyepieces - straight and lateral. The device provides the ability to examine at different magnifications. The straight eyepiece allows for panoramic examination with a single magnification, and with a contact method - with a 60-fold magnification.

The second (side) eyepiece enables panoramic examination with a magnification of 20 times, and when using the contact method - 150 times. Possible manipulations:

• Conventional panoramic hysteroscopy (single magnification) during panoramic examination through a straight eyepiece. Depth of view from infinity to 1 mm (from the distal end of the instrument), viewing angle 90°. During a general review of the uterine cavity, the localization of pathological changes is noted, and then they are examined with magnification.
• Panoramic macrohysteroscopy (20x magnification) using a lateral eyepiece is useful for cervicoscopy, colposcopy and macroscopic assessment of intrauterine pathology.
• Microhysteroscopy (60x magnification), the so-called contact hysteroscopy. A straight eyepiece is used, with its distal end in close contact with the endometrium. A field depth of 80 μm allows one to examine the structure of the normal mucous membrane and atypical areas.
• Microhysteroscopy (150x magnification) using a lateral eyepiece placed in contact with the mucous membrane allows for examination at the cellular level.

When working with a side eyepiece, focusing is done by rotating a special screw. It is necessary to keep in mind that contact hysteroscopy allows you to examine a surface with a diameter of 6-8 mm, therefore, to get a complete picture of the state of the uterine cavity, you need to move the hysteroscope many times. When combining all types of magnification of the micro-colpohysteroscope, you can get the most complete picture characterizing the state of the uterine cavity.

Microcolpohysteroscope Hamou II. Possible manipulations:

• Panoramic hysteroscopy (single magnification).
• Macrohysteroscopy (20x magnification).
• Microhysteroscopy (80x magnification).

This hysteroscope does not allow studying the structure of the cell; it is intended for intrauterine surgery.

Diagnostic and surgical hysteroscopes. The telescope for performing hysteroscopy is placed in an external metal case. There are two types of case: for diagnostic and surgical hysteroscopes.

• The body of the diagnostic hysteroscope has a diameter of 3-5.5 mm (depending on the manufacturer), is equipped with a tap for the flow of liquid or gas, and sometimes a second tap for their removal. There are also double-lumen tubes for separate supply and outflow of liquid (Fig. 2-6).
• The body of the operating hysteroscope has a diameter of 3.7-9 mm (depending on the manufacturer), most often double-lumen. Access to this channel is provided through a rubber valve to create a seal.

There are bodies equipped with a special deflecting device located at the distal end (albarran) and used to facilitate access of auxiliary instruments to hard-to-reach areas of the uterine cavity.

Optical surgical instruments (resector) are a metal body with a diameter of 7 mm (21 Fr). At its distal end are rigid scissors or variously shaped nippers and forceps. A telescope is inserted inside the body.

The telescope together with the resector are inserted into an outer casing equipped with taps for the introduction and outflow of liquid. This outer casing is equipped with an obturator. During the work, the latter is removed and the telescope with the instrument is placed in its place.

Optical surgical instruments have not found wide application due to the danger and complexity of working with them. When working with optics at a viewing angle of 30° (used most often), the cutting part of the instrument partially or completely (depending on the type of the working part) obscures the view and makes it difficult to work with this instrument.

Fibrohysteroscope

1. The diagnostic fibrohysteroscope - a flexible hysteroscope with fiber optics (Fig. 2-10) - has a number of advantages.
   • The small diameter (from 2.5 mm) of the distal end of the fibrohysteroscope allows performing hysteroscopy without dilating the cervical canal, without anesthesia, on an outpatient basis.
   • The flexibility of the device tip allows for examination of the uterine angles. Examination depth from 1 to 50 mm, large examination angle due to movement of the distal end.

The disadvantage of the fibrohysteroscope is the honeycomb structure of the image, caused by the peculiarities of light transmission through an optical cable consisting of many optical fibers, which degrades the quality and accuracy of the image. This may lead to errors in the interpretation of the hysteroscopic image.

2. In addition to the diagnostic one, there is an operational fibrohysteroscope with a working part diameter of 4.5 mm and an operational channel of 2.2 mm. The inspection depth is 2-50 mm, the inspection angle is 120°. However, the operational capabilities of this hysteroscope are small, since the narrow operational channel allows the introduction of only some types of thin instruments, with the help of which it is possible to perform only a targeted biopsy of the endometrium, the removal of small endometrial polyps and the dissection of delicate intrauterine adhesions.

Due to its low operational capabilities and high cost, the fibrohysteroscope has not yet found wide application in our country. Abroad, it is widely used for outpatient diagnostic hysteroscopy.

A resectoscope is the main instrument for electrosurgical operations performed in the uterine cavity. Resectoscopes are produced by manufacturers under various names: resectoscope (Karl Storz), myomaresectoscope (Wolf), hysteroresectoscope (Olympus, Circon-Acmi).

The resectoscope consists of 5 parts: a telescope, an outer and inner tube, a working element and an electrode.

The telescope is represented by panoramic rigid optics "Hamou" and "Hopkins" with a diameter of 4 mm, the viewing angle can be different. The most popular telescope has a viewing angle of 30°.

The resectoscope tube consists of two parts (external and internal, made of stainless steel); the fluid supply and outflow flows are separated. The diameter of the outer body varies from 6.3 to 9 mm (19-27 Fr), the working length is 18-35 cm. The outer tube has numerous holes at the distal end designed for aspiration of fluid from the uterine cavity. The inner tube in the latest generation of resectoscopes is equipped with a rotation mechanism that allows for rotational movements of the working element relative to the tube. Such a design facilitates the operation, does not create difficulties with kinks in numerous connecting hoses when changing the position of the working element.

Electrodes of various shapes, sizes and diameters are connected to the working element: cutting loops (straight and curved), a knife, rake-shaped, needle-shaped, spherical and cylindrical electrodes, as well as evaporating electrodes.

The larger the diameter of the cutting loop, the safer and more effective it is. Small loops increase the duration of the operation and increase the risk of uterine perforation. Cutting loops with an angle of inclination away from the surgeon are used for resection of the endometrium in the area of the corners and bottom of the uterus, loops with an angle of inclination towards the surgeon are used for resection of the endometrium of the walls of the uterine cavity.

Large sizes of spherical or cylindrical electrodes are preferable for quick completion of the operation, but they make the view more difficult. Therefore, for normal uterine sizes, small electrodes are preferable.

The working element of the resectoscope is controlled by pressing the trigger with a finger. There are two working mechanisms: active and passive. With the active mechanism, the electrode is pulled out of the housing by pressing the trigger. With the passive mechanism, the electrode automatically returns to the housing after the trigger is released, performing tissue cutting or coagulation. The passive mechanism is safer to operate. In the design of the working element, the electrode is placed in such a way that when it is pulled out of the tube, the working surface of the electrode is constantly in the visibility zone.

Auxiliary tools

To perform intrauterine surgical interventions, hysteroscopes are equipped with sets of rigid, semi-rigid and flexible instruments: biopsy forceps, serrated biopsy forceps, grasping forceps, scissors, endoscopic catheters and probes for bougienage of the fallopian tubes. These instruments are passed through the surgical channel of the hysteroscope and used for intrauterine manipulations. These instruments are quite fragile, easily break and deform. Scissors can be used to cut off small polyps and fibroids, sometimes to dissect a thin intrauterine septum and delicate intrauterine adhesions. Biopsy forceps allow you to perform a targeted biopsy of the endometrium, excise small polyps or polyp stalks in the area of the uterine angles.

An electrical conductor in an insulated housing can also be passed through the hysteroscope's operating channel to coagulate the openings of the fallopian tubes for sterilization. A laser conductor can also be passed through the same channel.

Most often, gynecologists use the Nd-YAG laser, which has a wavelength of 1.064 nm and destroys tissue to a depth of 4-6 mm. The laser is used for ablation of the endometrium, myomectomy, and dissection of the intrauterine septum.

Equipment used to dilate the uterine cavity

The uterine cavity can be expanded by introducing fluid or gas.

To deliver fluid into the uterine cavity, various fairly simple devices as well as complex electronic devices are used.

The fluid can be injected into the uterine cavity using a Janet syringe. A container (jar or bag) with the fluid can be placed at a height of 1 m (74 mm Hg) or 1.5 m (110 mm Hg) above the patient, in which case the fluid enters the uterine cavity under the force of gravity. Another option is to attach a rubber bulb or a pressure cuff (manual or automatic) to the container with the fluid. In this case, a certain pressure is maintained in the uterine cavity, and excess fluid, washing the cavity, flows out through the dilated cervical canal. These are cheap and accessible methods that provide good image quality.

However, when performing long intrauterine operations, in order to avoid serious complications, it is preferable to use various pumps that supply fluid at a certain speed and pressure into the uterine cavity. The most advanced in this regard is considered to be the complex electronic device Endomat.

Endomat is a combined device used for lavage and aspiration in both hysteroscopic and laparoscopic surgery. The selection of appropriate parameters for installation occurs automatically in accordance with the attached set of tubes. Their display on the monitor allows the surgeon to control the fluid supply rate and pressure in the uterine cavity during the intervention. An electronic safety system interrupts lavage/aspiration in the event of a prolonged deviation of parameters from the preset ones. The use of Endomat in intrauterine operations can significantly reduce the likelihood of complications. The only drawback of this device is its high cost.

The hysteroflator is a complex electronic device required to supply gas into the uterine cavity. The gas supply rate is from 0 to 100 ml/min, the achieved pressure in the uterine cavity is up to 100 or 200 mm Hg (depending on the manufacturer).

Equipment for performing hysteroscopy

A light source is necessary for performing an endoscopic examination. To improve the quality of work, it is necessary to use very intense light sources. When performing diagnostic hysteroscopy, a halogen light source with a power of 150 W is sufficient. But for performing complex operations using a video camera, it is preferable to use a halogen light source with a power of 250 W or a xenon light source with a power of 175-300 W. The most ideal xenon light source is XENON NOVA ("Karl Storz"). The spectrum of a xenon lamp is close to the spectrum of sunlight, so the quality of photographs is the best. Immediately after turning on the lamp, the illumination intensity reaches its maximum. In addition, the intensity of the luminous flux in a xenon light source can be automatically controlled by an endoscopic video camera or adjusted manually.

Light is supplied from the light source to the endoscope through flexible fiber optic light guides with a diameter of 3.6 and 4.8 mm.

High-frequency voltage generator. When performing electrosurgical operations, a high-frequency voltage generator is required.

Due to the high concentration of electrolytes, biological tissues have sufficient electrical conductivity. High-frequency electric current is used for cutting and coagulating tissues. Low-frequency current cannot be used, as it causes muscle contraction. At a frequency of more than 100 kHz, this effect is insignificant. Generators currently used have a frequency of 475-750 kHz.

When performing operations using high-frequency current, the following types of equipment are used:

1. Monopolar surgical technique. Electric current flows from the active small electrode to the passive or neutral large electrode. The patient's body is always part of a closed electric circuit. Tissue cutting or coagulation occurs on the active electrode.
2. Bipolar surgical technique. Electric current passes between two connected electrodes. Depending on the type of surgical procedure (cutting or coagulation), the electrodes are of the same or different sizes. In this case, only a small part of the tissue between the electrodes is included in the electric circuit.

Monopolar coagulation is used in operative hysteroscopy.

High-frequency surgery involves certain risks for the staff and the patient (e.g. unintentional thermal tissue damage). Knowing the possible causes and following safety instructions can minimize the risk.

The most advanced high-frequency voltage generators are the Autocon-200 and Autocon-350. There is a function of automatic control and regulation of the depth of the cut and the degree of coagulation, in addition, these devices provide a high degree of safety for the surgeon and the patient.

Video camera and monitor. The use of an endoscopic video camera with a video monitor significantly facilitates the surgeon's work. The video camera allows recording the course of the examination on videotape and taking photographs, which creates the opportunity to demonstrate the procedure to colleagues in the operating room and for further training.

The video monitor provides greater magnification, freedom of manipulation, reduces the strain on the surgeon's eyes, and allows the doctor to take a comfortable position. Some types of intrauterine operations are possible only with the use of a video monitor.

In recent years, endovideo cameras have been significantly improved, resulting in increased resolution and increased light sensitivity. High-quality single-chip Endovision HYSTEROCAM SL and Endovision TELECAM SL ("Karl Storz") video cameras can be used for hysteroscopy. The most advanced is considered to be the Endovision TRICAM SL ("Karl Storz") video camera with even greater resolution.

The use of the latest advances in computer technology now allows for the correction of the image on the monitor screen during surgery - detailing the structure of an object (DIGIVIDEO), creating a picture in a picture (TWINVIDEO), rotating the image in different planes and projections (REVERSE VIDEO) ("Karl Storz"),

Endoscopic cameras and video monitors are produced by various companies, including domestic ones.

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