Hysteroscopes and sheaths

The rigid, direct optical hysteroscope, which is derived from the cystoscope, uses fluid- or gas-distending media to obtain a wide-angle view of the uterine cavity. This hysteroscope takes advantage of a system of lenses and prisms to give the operator a well-illuminated image, with excellent contrast and resolution. The most widely used optical hysteroscopes have an outer diameter of 3–4 mm, but thinner rigid scopes with fibre optics and an outer diameter of 1.9 mm have been developed.

Fibre-optic hysteroscopy was developed as a simple mechanism for viewing the uterine cavity with the use of gas as distending media. Fibre-optic hysteroscopy is inferior to the direct optical hysteroscopy for evaluating the uterine cavity because of a lower contrast and resolution of the images that are a composite of individual fibres.

Both optical and fibre-optic hysteroscopes are monocular and provide little depth perception. They are available with different viewing angles, from 0–70°. Thirty-degree scopes are most commonly used for diagnostic procedures. Smaller angles of deflection are used in operative procedures. The hysteroscopes are easily attached to video-monitoring systems.

The hysteroscope is inserted, securely fastened or permanently affixed into a metallic sleeve or sheath. Removable obturators are available for easy introduction of the sheath into the uterine cavity. Obturators are especially useful when dilatation is difficult or when large sheaths are being used.

Diagnostic sheaths generally have an outer diameter between 2.5 and 5.5 mm, and operative sheaths have an outer diameter between 5.5 and 9.0 mm. Both diagnostic and operative sheaths are fitted with stopcocks or ports for the instillation of distending media.

Modern diagnostic and operative sheaths have isolated, dual ports, and provide continuous laminar flow of distending media. Continuous flow with separated in- and outflow channels guarantees the optimal irrigation and imaging of the uterine cavity, and allows optimal intrauterine pressure and degree of cavity distension. In- and outflow can be regulated with separate stopcocks. Operative sheaths are designed to allow the passage of one or more operative instruments. A right-angle hysteroscope allows for direct insertion of rigid operating instruments; these sheaths have an outer diameter of 5–9 mm.

New developments in hysteroscopes and sheaths were generally dominated by decreasing outer diameter without losing the quality of the image. Although newer hysteroscopes provide separate in- and outflow channels, the inflow channel is often also designed as the working channel for the introduction of surgical instruments. In the case of a small outer diameter, the small fluid inflow channel can be mostly obstructed by the introduced instruments in such cases, causing impaired viewing. Therefore, further downsizing the outer diameter of hysteroscopes should not impair channel size further; more can be expected from the introduction of optical chip technology in hysteroscopes, such as the Invisio ^® Digital Hysteroscope (GyrusACMI/Olympus, Tokyo, Japan).

Operative instruments and catheters

An assortment of rigid, semi-rigid, and flexible instruments have been developed or adapted for hysteroscopic surgery. The rigid and semi-rigid instruments include scissors, grasping forceps, and biopsy forceps. Most instruments are inserted through an operating channel, which is often the combined inflow channel for fluid too. Special care should be taken when handling them, as the handle, shaft and tips can be easily damaged.

Flexible, specifically adapted catheters, can also be inserted through the hysteroscopic sheath for tubal cannulation, selective chromopertubation, or for tubal sterilisation. The most commonly applied technique is the Essure ^® hysteroscopic sterilisation method (Conceptus, Mountain View CA, USA), which has been distributed for over 10 years. The system comprises two micro-inserts for intraluminal tubal occlusion, which are positioned using a disposable delivery system. Each micro-insert consists of a stainless steel inner coil, a nickel-titanium expanding outer coil, and polyethylene terephthalate fibres wound in and around the inner coil. When released from the delivery system, the outer coil expands to 1.5–2.0 mm in diameter to anchor the micro-insert in the variable diameters and shapes of the proximal fallopian tube. With hysteroscopic guidance, the micro-inserts are placed through the utero-tubal junction to reach the more proximal portion of the Fallopian tube. The polyethylene terephthalate fibres incite local fibrocyte proliferation, resulting in luminal occlusion, typically within 3 months. Almost 500,000 women worldwide have been successfully sterilised with the technique, with an effectiveness at 5 years above 99.7% (data Conceptus, Mountain View CA, USA) One of the disadvantages of hysteroscopic techniques, compared with laparoscopic techniques, is that women need a specific reference test (e.g. transvaginal ultrasound or hysterosalpingography) after a few months before they can rely on an effective blocking of their tubes. Another disadvantage is that, in about 5% of women, successful bilateral occlusion at the first procedure is not possible; reasons for failure include inability to view or access the tubal ostia, expulsion, perforation, and malplacement (data Conceptus, Mountain View CA, USA) The clinician should discuss this possibility with the patient. Laparoscopic sterilisation or, alternatively, another attempt of Essure ^® placement, can be attempted at a later date.

New developments in instruments and catheters are mainly related to hysteroscopic sterilisation. Recently, an alternative technique, Adiana ^® (Hologic, Bedford MA, USA), based on silicon ingrowth in the intramural tubal lumen after electrocautery, was launched and then withdrawn because of patent infringement problems and disappointing sales. The Essure ^® system has recently been improved further by introducing new catheters with better device-releasing properties. In the near future, techniques that immediately block the tubes, without the need for any reference tests, will be introduced for further clinical testing. A future indication for blocking the intramural part of the tubes will most likely include hydrosalpinges in combination with the need for in-vitro fertilisation (IVF) and intra-cytoplasmic sperm injection (ICSI).

Resectoscope

The hysteroscopic resectoscope is a modification of the urologic resectoscope. Its assembly requires practice and should be mastered before surgical procedures are undertaken. The sheath has an outer diameter of 7–9 mm, and includes both inflow and outflow ports for distending media. The resectoscope is equipped with continuous flow and provides excellent irrigation for operative procedures. If surgical debris or the so-called ‘chips’ block the operative field, the resectoscope can be removed while the sheath is left in place. This allows for removal of large tissue while maintaining cervical dilatation. Electrosurgical instruments or electrodes can be inserted into an attachment to a spring handle, which allows the surgeon to move the surgical electrode inward and outward.

In cases of monopolar high-frequency electrosurgery, the woman must be grounded and a non-electrolyte, non-conducting, distending medium must be used. The more modern bipolar resectoscopes are used with saline-distending media. Although bipolar techniques are less hazardous because of intravasation and electrolyte blood-imbalances, more gas-bubbles may hamper visualisation, and gas-emboli might even cause spasms in the lung capillaries, potentially disturbing gas diffusion in the lungs.

New developments in resectoscopy are based on smaller outer diameter and bipolar electrosurgery. The use of bipolar techniques with saline irrigation and distention reduces the effects of fluid intravasation, as no electrolyte changes occur. Fluid input and output should still also be monitored. If excessive intravasation occurs, the isotonic fluid overload is generally readily treatable with diuretics (e.g. furosemide 20 mg intravenously). Therefore, a higher amount of intravasation during surgery can be accepted. Generally, most protocols and guidelines mention about 2500 ml as the upper limit of saline intravasation.

Electrocautery and laser

Electrocautery instruments, such as a loop or needle electrode, roller ball, and button (or ‘mushroom’) electrode, have been adapted for the hysteroscope or resectoscope. Both the roller ball and the loop electrode can be used for endometrial ablation. In addition, the loop can be used for excision of submucous myomas, endometrial polyps, and the needle for the resection of uterine septa and small polyps. The button electrode is applied for coagulation of vessels or areas of endometrial lining. Bipolar electrodes are preferred nowadays, as they have the same less hazardous intravasation risks as resectoscopy with the use of saline for irrigation and distension of the cavity.

Lasers (e.g. neodymium: yttrium–aluminum–garnet; potassium-titanyl-phosphate, and argon) offer no advantages over electrocoagulation. As these lasers are more expensive and more dangerous, the use of them has almost disappeared.

No new significant developments have taken place in electrocautery instruments or lasers. The main disadvantage of bipolar compared with monopolar electrodes is the higher number of gas-bubbles that are created and disturbing visibility. Although electrodes have improve, the problem has not been solved completely.

Morcellation

Tissue that has been cut must be removed from the uterine cavity by taking out the hysteroscope after grasping the loose tissue elements with forceps or the loop-electrode in the case of the resectoscope. Although the removal of tissue under visual control, instead of using a curette, is the most effective way, it takes a number of steps, which can be tiring in the long run, inconvenient to carry out, and consequently hard to learn. For these reasons, operative hysteroscopy has a long learning curve, and the number of gynaecologists that carry out operative hysteroscopy is still low. Therefore, alternative techniques are needed that are easier to learn and have less associated risks.

The hysteroscopic morcellator could resolve some of the above-mentioned difficulties. I developed The TRUCLEAR™ (Smith and Nephew, Andover MA, USA) technique, which is based on an instrument that consists of a set of two metal hollow rigid tubes that fit into each other. The inner tube rotates within the outer tube, is driven mechanically by an electrically powered control unit, and is controlled by a foot pedal that activates the rotation and regulates the direction of rotation of the inner tube. The control unit is connected to a handheld motor drive unit in which the morcellator is inserted. Both tubes have a window-opening at the end with cutting edges. By means of a vacuum source connected to the inner tube, the tissue is sucked into the window-opening, cut and ‘shaved’ as the inner tube is rotated. The system uses no electrocoagulation, and there is no lateral thermal or electrical energy spread. Haemostasis occurs by spontaneous myometrial contraction. The removed tissue is discharged through the device, is collected in a tissue-trap, and is available for pathology analysis. As only one introduction is needed, the number of perforations is extremely low. The 4.0-mm morcellator is introduced in the uterine cavity through a straight-forward working-channel of a continuous flow 8–9 mm rigid hysteroscope. After dilatation of the internal orifice of the uterine cervix, atraumatic insertion is accomplished with the use of an obturator in the outer sheath of the hysteroscope. Saline solution is used for distension and irrigation.

Van Dongen et al. conducted a randomised-controlled trial (RCT) to compare conventional resectoscopy and hysteroscopic morcellation among residents in training. The mean operating time for resectosocpy and morcellation was 17.0 (95% confidence interval [95% CI] 14.1 to 17.9, standard deviation (SD) 8.4) and 10.6 (95% CI 7.3 to 14.0, SD 9.5) mins, respectively ( P = 0.008). Subjective surgeon and trainer scores for convenience of technique on a visual analogue scale were in favour of the morcellator.

A new development in hysteroscopic morcellation is the recent availability of a smaller outer diameter TRUCLEAR™ system, with a 2.9-mm cutting-blade and a 5.0-mm hysteroscope for office or ambulatory use with no or local anaesthesia. Polyps, small myomas, and retained products of pregnancy can be removed in that way. A new morcellator system MyoSure ^® was recently introduced by Hologic (Bedford MA, USA). A recent patent infringement US jury-verdict could jeopardise its future availability. Another company that recently introduced an alternative device is Storz (Tuttlingen, Germany).

Distension and irrigation

Carbon dioxide (CO2) is rapidly absorbed and easily cleared from the body by respiration. The gas easily flows through narrow channels in small-diameter scopes that can be used for office-based diagnostic hysteroscopy. This method, however, offers no way to clear blood from the scope. With CO2, a hysteroscopic insufflator is required to regulate flow and limit maximal intrauterine pressure.

The advantage of fluid over gas is the symmetric distention of the uterus with fluid and its effective ability to flush blood, mucus, bubbles, and small tissue fragments out of the visual field. A pressure of 60–80 mm Hg is usually adequate for uterine distention with low viscosity fluids like saline.

Various delivery systems are designed to suit the media used for uterine distention and to accurately record volumes of inflow and outflow. This recording is important because fluid can leave the uterus by means of a fluid outflow channel, a mechanical morcellator, cervical or tubal leakage, or intravasation. Hanging, gravity-fed containers to deliver fluid can be raised or compressed with a cuff; however, these can be unreliable in estimating intrauterine pressures. Pumps are available to monitor pressure and volume for liquid media. Media then usually flow into the uterine cavity through an inner sheath around the hysteroscope. A perforated outer sheath is used for collection or outflow of media. This design creates laminar flow, which keeps the visual field clear.

Normal saline and lactated Ringer solution are isotonic, conductive, low-viscosity fluids, which can be used for diagnostic hysteroscopy and for mechanical and bipolar operative procedures.

The hypotonic, non-conductive, low-viscosity fluids mannitol (5%), sorbitol (3–5%), and glycine (1.5%), should be used only with monopolar operative procedures. Absorption of large volumes of electrolyte-free, low-viscosity fluid may result in volume overload with water intoxication, pulmonary oedema, hyponatraemia, hypo-osmolarity, and cerebral oedema, but these are extremely rare in office procedures. Nausea and malaise are the earliest findings, and may be seen when the plasma sodium concentration falls to 5 mmol/l (this relates to an intravasation of 500 ml of electrolyte-free fluids). This may be followed by headache, lethargy, and obtundation, and eventually seizures, coma and respiratory arrest if the plasma sodium concentration falls between 10 and 15 mmol/l.

New developments are the availability of newer fluid-management systems that are more reliable and precise in measuring in- and outflow fluids, and therefore improve patient safety. Furthermore, most improvements result in better ergonomy and, therefore, systems become less inconvenient for hospital staff.

Virtual hysteroscopy

During the past decade, transvaginal ultrasonography of the uterus has become a routine procedure in the diagnostic work-up of several gynaecological problems. A normal sonographic finding has been shown to be accurate for the exclusion of clinically significant intra-cavitary abnormalities. Furthermore, this normal sonographic finding is well reproduced in the hands of different examiners. In the case of abnormal or inconclusive sonographic findings, however, diagnostic accuracy and reproducibility decline.

To improve the image in these cases, sonographic examination using artificial uterine cavity distension was first described at our department. Saline infusion sonohysterography (SIS) has been extensively described. It is accepted that SIS improves the diagnostic accuracy of transvaginal ultrasonography in cases of abnormal or inconclusive findings, and that SIS is an effective early diagnostic step in the evaluation of women with pre- and postmenopausal abnormal uterine bleeding.

The only contraindications are pregnancy and pelvic infection. Although the visualisation of the uterine cavity and its linings improves significantly, women experience discomfort resulting from either fluid leakage, while using a catheter without a balloon, or pain with the use of a balloon catheter. In trying to overcome these disadvantages, and to create a more stable filling of the uterine cavity, we modified the technique of SIS by instilling gel instead of flushing or infusing saline. This new technique and first experiences of gel instillation sonohysterography (GIS) have been described. Three- and four-dimensional ultrasound images can only be achieved when stable and adequate distension of the uterine cavity is achieved. This can only be achieved by the use of gel. We use the term ‘virtual hysteroscopy’ for such type of imaging. Further improvement of ultrasound technology and computer processing will create images revealing diagnostic information that is equal to diagnostic hysteroscopy with comparable or less pain, inconvenience for the woman, or both.

The latest development in this field is the method to change the gel during dilution into a stable foam that is fluid enough to pass patent tubes and can be observed as a white echodense contrast during transvaginal ultrasonography in cases of a fertility work-up (hysterosalpingo-foam sonography [HyFoSy]).

Hysteroscopes and sheaths

The rigid, direct optical hysteroscope, which is derived from the cystoscope, uses fluid- or gas-distending media to obtain a wide-angle view of the uterine cavity. This hysteroscope takes advantage of a system of lenses and prisms to give the operator a well-illuminated image, with excellent contrast and resolution. The most widely used optical hysteroscopes have an outer diameter of 3–4 mm, but thinner rigid scopes with fibre optics and an outer diameter of 1.9 mm have been developed.

Fibre-optic hysteroscopy was developed as a simple mechanism for viewing the uterine cavity with the use of gas as distending media. Fibre-optic hysteroscopy is inferior to the direct optical hysteroscopy for evaluating the uterine cavity because of a lower contrast and resolution of the images that are a composite of individual fibres.

Both optical and fibre-optic hysteroscopes are monocular and provide little depth perception. They are available with different viewing angles, from 0–70°. Thirty-degree scopes are most commonly used for diagnostic procedures. Smaller angles of deflection are used in operative procedures. The hysteroscopes are easily attached to video-monitoring systems.

The hysteroscope is inserted, securely fastened or permanently affixed into a metallic sleeve or sheath. Removable obturators are available for easy introduction of the sheath into the uterine cavity. Obturators are especially useful when dilatation is difficult or when large sheaths are being used.

Diagnostic sheaths generally have an outer diameter between 2.5 and 5.5 mm, and operative sheaths have an outer diameter between 5.5 and 9.0 mm. Both diagnostic and operative sheaths are fitted with stopcocks or ports for the instillation of distending media.

Modern diagnostic and operative sheaths have isolated, dual ports, and provide continuous laminar flow of distending media. Continuous flow with separated in- and outflow channels guarantees the optimal irrigation and imaging of the uterine cavity, and allows optimal intrauterine pressure and degree of cavity distension. In- and outflow can be regulated with separate stopcocks. Operative sheaths are designed to allow the passage of one or more operative instruments. A right-angle hysteroscope allows for direct insertion of rigid operating instruments; these sheaths have an outer diameter of 5–9 mm.

New developments in hysteroscopes and sheaths were generally dominated by decreasing outer diameter without losing the quality of the image. Although newer hysteroscopes provide separate in- and outflow channels, the inflow channel is often also designed as the working channel for the introduction of surgical instruments. In the case of a small outer diameter, the small fluid inflow channel can be mostly obstructed by the introduced instruments in such cases, causing impaired viewing. Therefore, further downsizing the outer diameter of hysteroscopes should not impair channel size further; more can be expected from the introduction of optical chip technology in hysteroscopes, such as the Invisio ^® Digital Hysteroscope (GyrusACMI/Olympus, Tokyo, Japan).

Operative instruments and catheters

An assortment of rigid, semi-rigid, and flexible instruments have been developed or adapted for hysteroscopic surgery. The rigid and semi-rigid instruments include scissors, grasping forceps, and biopsy forceps. Most instruments are inserted through an operating channel, which is often the combined inflow channel for fluid too. Special care should be taken when handling them, as the handle, shaft and tips can be easily damaged.

Flexible, specifically adapted catheters, can also be inserted through the hysteroscopic sheath for tubal cannulation, selective chromopertubation, or for tubal sterilisation. The most commonly applied technique is the Essure ^® hysteroscopic sterilisation method (Conceptus, Mountain View CA, USA), which has been distributed for over 10 years. The system comprises two micro-inserts for intraluminal tubal occlusion, which are positioned using a disposable delivery system. Each micro-insert consists of a stainless steel inner coil, a nickel-titanium expanding outer coil, and polyethylene terephthalate fibres wound in and around the inner coil. When released from the delivery system, the outer coil expands to 1.5–2.0 mm in diameter to anchor the micro-insert in the variable diameters and shapes of the proximal fallopian tube. With hysteroscopic guidance, the micro-inserts are placed through the utero-tubal junction to reach the more proximal portion of the Fallopian tube. The polyethylene terephthalate fibres incite local fibrocyte proliferation, resulting in luminal occlusion, typically within 3 months. Almost 500,000 women worldwide have been successfully sterilised with the technique, with an effectiveness at 5 years above 99.7% (data Conceptus, Mountain View CA, USA) One of the disadvantages of hysteroscopic techniques, compared with laparoscopic techniques, is that women need a specific reference test (e.g. transvaginal ultrasound or hysterosalpingography) after a few months before they can rely on an effective blocking of their tubes. Another disadvantage is that, in about 5% of women, successful bilateral occlusion at the first procedure is not possible; reasons for failure include inability to view or access the tubal ostia, expulsion, perforation, and malplacement (data Conceptus, Mountain View CA, USA) The clinician should discuss this possibility with the patient. Laparoscopic sterilisation or, alternatively, another attempt of Essure ^® placement, can be attempted at a later date.

New developments in instruments and catheters are mainly related to hysteroscopic sterilisation. Recently, an alternative technique, Adiana ^® (Hologic, Bedford MA, USA), based on silicon ingrowth in the intramural tubal lumen after electrocautery, was launched and then withdrawn because of patent infringement problems and disappointing sales. The Essure ^® system has recently been improved further by introducing new catheters with better device-releasing properties. In the near future, techniques that immediately block the tubes, without the need for any reference tests, will be introduced for further clinical testing. A future indication for blocking the intramural part of the tubes will most likely include hydrosalpinges in combination with the need for in-vitro fertilisation (IVF) and intra-cytoplasmic sperm injection (ICSI).

Resectoscope

The hysteroscopic resectoscope is a modification of the urologic resectoscope. Its assembly requires practice and should be mastered before surgical procedures are undertaken. The sheath has an outer diameter of 7–9 mm, and includes both inflow and outflow ports for distending media. The resectoscope is equipped with continuous flow and provides excellent irrigation for operative procedures. If surgical debris or the so-called ‘chips’ block the operative field, the resectoscope can be removed while the sheath is left in place. This allows for removal of large tissue while maintaining cervical dilatation. Electrosurgical instruments or electrodes can be inserted into an attachment to a spring handle, which allows the surgeon to move the surgical electrode inward and outward.

In cases of monopolar high-frequency electrosurgery, the woman must be grounded and a non-electrolyte, non-conducting, distending medium must be used. The more modern bipolar resectoscopes are used with saline-distending media. Although bipolar techniques are less hazardous because of intravasation and electrolyte blood-imbalances, more gas-bubbles may hamper visualisation, and gas-emboli might even cause spasms in the lung capillaries, potentially disturbing gas diffusion in the lungs.

New developments in resectoscopy are based on smaller outer diameter and bipolar electrosurgery. The use of bipolar techniques with saline irrigation and distention reduces the effects of fluid intravasation, as no electrolyte changes occur. Fluid input and output should still also be monitored. If excessive intravasation occurs, the isotonic fluid overload is generally readily treatable with diuretics (e.g. furosemide 20 mg intravenously). Therefore, a higher amount of intravasation during surgery can be accepted. Generally, most protocols and guidelines mention about 2500 ml as the upper limit of saline intravasation.

Electrocautery and laser

Electrocautery instruments, such as a loop or needle electrode, roller ball, and button (or ‘mushroom’) electrode, have been adapted for the hysteroscope or resectoscope. Both the roller ball and the loop electrode can be used for endometrial ablation. In addition, the loop can be used for excision of submucous myomas, endometrial polyps, and the needle for the resection of uterine septa and small polyps. The button electrode is applied for coagulation of vessels or areas of endometrial lining. Bipolar electrodes are preferred nowadays, as they have the same less hazardous intravasation risks as resectoscopy with the use of saline for irrigation and distension of the cavity.

Lasers (e.g. neodymium: yttrium–aluminum–garnet; potassium-titanyl-phosphate, and argon) offer no advantages over electrocoagulation. As these lasers are more expensive and more dangerous, the use of them has almost disappeared.

No new significant developments have taken place in electrocautery instruments or lasers. The main disadvantage of bipolar compared with monopolar electrodes is the higher number of gas-bubbles that are created and disturbing visibility. Although electrodes have improve, the problem has not been solved completely.

Morcellation

Tissue that has been cut must be removed from the uterine cavity by taking out the hysteroscope after grasping the loose tissue elements with forceps or the loop-electrode in the case of the resectoscope. Although the removal of tissue under visual control, instead of using a curette, is the most effective way, it takes a number of steps, which can be tiring in the long run, inconvenient to carry out, and consequently hard to learn. For these reasons, operative hysteroscopy has a long learning curve, and the number of gynaecologists that carry out operative hysteroscopy is still low. Therefore, alternative techniques are needed that are easier to learn and have less associated risks.

The hysteroscopic morcellator could resolve some of the above-mentioned difficulties. I developed The TRUCLEAR™ (Smith and Nephew, Andover MA, USA) technique, which is based on an instrument that consists of a set of two metal hollow rigid tubes that fit into each other. The inner tube rotates within the outer tube, is driven mechanically by an electrically powered control unit, and is controlled by a foot pedal that activates the rotation and regulates the direction of rotation of the inner tube. The control unit is connected to a handheld motor drive unit in which the morcellator is inserted. Both tubes have a window-opening at the end with cutting edges. By means of a vacuum source connected to the inner tube, the tissue is sucked into the window-opening, cut and ‘shaved’ as the inner tube is rotated. The system uses no electrocoagulation, and there is no lateral thermal or electrical energy spread. Haemostasis occurs by spontaneous myometrial contraction. The removed tissue is discharged through the device, is collected in a tissue-trap, and is available for pathology analysis. As only one introduction is needed, the number of perforations is extremely low. The 4.0-mm morcellator is introduced in the uterine cavity through a straight-forward working-channel of a continuous flow 8–9 mm rigid hysteroscope. After dilatation of the internal orifice of the uterine cervix, atraumatic insertion is accomplished with the use of an obturator in the outer sheath of the hysteroscope. Saline solution is used for distension and irrigation.

Van Dongen et al. conducted a randomised-controlled trial (RCT) to compare conventional resectoscopy and hysteroscopic morcellation among residents in training. The mean operating time for resectosocpy and morcellation was 17.0 (95% confidence interval [95% CI] 14.1 to 17.9, standard deviation (SD) 8.4) and 10.6 (95% CI 7.3 to 14.0, SD 9.5) mins, respectively ( P = 0.008). Subjective surgeon and trainer scores for convenience of technique on a visual analogue scale were in favour of the morcellator.

A new development in hysteroscopic morcellation is the recent availability of a smaller outer diameter TRUCLEAR™ system, with a 2.9-mm cutting-blade and a 5.0-mm hysteroscope for office or ambulatory use with no or local anaesthesia. Polyps, small myomas, and retained products of pregnancy can be removed in that way. A new morcellator system MyoSure ^® was recently introduced by Hologic (Bedford MA, USA). A recent patent infringement US jury-verdict could jeopardise its future availability. Another company that recently introduced an alternative device is Storz (Tuttlingen, Germany).

Distension and irrigation

Carbon dioxide (CO2) is rapidly absorbed and easily cleared from the body by respiration. The gas easily flows through narrow channels in small-diameter scopes that can be used for office-based diagnostic hysteroscopy. This method, however, offers no way to clear blood from the scope. With CO2, a hysteroscopic insufflator is required to regulate flow and limit maximal intrauterine pressure.

The advantage of fluid over gas is the symmetric distention of the uterus with fluid and its effective ability to flush blood, mucus, bubbles, and small tissue fragments out of the visual field. A pressure of 60–80 mm Hg is usually adequate for uterine distention with low viscosity fluids like saline.

Various delivery systems are designed to suit the media used for uterine distention and to accurately record volumes of inflow and outflow. This recording is important because fluid can leave the uterus by means of a fluid outflow channel, a mechanical morcellator, cervical or tubal leakage, or intravasation. Hanging, gravity-fed containers to deliver fluid can be raised or compressed with a cuff; however, these can be unreliable in estimating intrauterine pressures. Pumps are available to monitor pressure and volume for liquid media. Media then usually flow into the uterine cavity through an inner sheath around the hysteroscope. A perforated outer sheath is used for collection or outflow of media. This design creates laminar flow, which keeps the visual field clear.

Normal saline and lactated Ringer solution are isotonic, conductive, low-viscosity fluids, which can be used for diagnostic hysteroscopy and for mechanical and bipolar operative procedures.

The hypotonic, non-conductive, low-viscosity fluids mannitol (5%), sorbitol (3–5%), and glycine (1.5%), should be used only with monopolar operative procedures. Absorption of large volumes of electrolyte-free, low-viscosity fluid may result in volume overload with water intoxication, pulmonary oedema, hyponatraemia, hypo-osmolarity, and cerebral oedema, but these are extremely rare in office procedures. Nausea and malaise are the earliest findings, and may be seen when the plasma sodium concentration falls to 5 mmol/l (this relates to an intravasation of 500 ml of electrolyte-free fluids). This may be followed by headache, lethargy, and obtundation, and eventually seizures, coma and respiratory arrest if the plasma sodium concentration falls between 10 and 15 mmol/l.

New developments are the availability of newer fluid-management systems that are more reliable and precise in measuring in- and outflow fluids, and therefore improve patient safety. Furthermore, most improvements result in better ergonomy and, therefore, systems become less inconvenient for hospital staff.

Virtual hysteroscopy

During the past decade, transvaginal ultrasonography of the uterus has become a routine procedure in the diagnostic work-up of several gynaecological problems. A normal sonographic finding has been shown to be accurate for the exclusion of clinically significant intra-cavitary abnormalities. Furthermore, this normal sonographic finding is well reproduced in the hands of different examiners. In the case of abnormal or inconclusive sonographic findings, however, diagnostic accuracy and reproducibility decline.

To improve the image in these cases, sonographic examination using artificial uterine cavity distension was first described at our department. Saline infusion sonohysterography (SIS) has been extensively described. It is accepted that SIS improves the diagnostic accuracy of transvaginal ultrasonography in cases of abnormal or inconclusive findings, and that SIS is an effective early diagnostic step in the evaluation of women with pre- and postmenopausal abnormal uterine bleeding.

The only contraindications are pregnancy and pelvic infection. Although the visualisation of the uterine cavity and its linings improves significantly, women experience discomfort resulting from either fluid leakage, while using a catheter without a balloon, or pain with the use of a balloon catheter. In trying to overcome these disadvantages, and to create a more stable filling of the uterine cavity, we modified the technique of SIS by instilling gel instead of flushing or infusing saline. This new technique and first experiences of gel instillation sonohysterography (GIS) have been described. Three- and four-dimensional ultrasound images can only be achieved when stable and adequate distension of the uterine cavity is achieved. This can only be achieved by the use of gel. We use the term ‘virtual hysteroscopy’ for such type of imaging. Further improvement of ultrasound technology and computer processing will create images revealing diagnostic information that is equal to diagnostic hysteroscopy with comparable or less pain, inconvenience for the woman, or both.

The latest development in this field is the method to change the gel during dilution into a stable foam that is fluid enough to pass patent tubes and can be observed as a white echodense contrast during transvaginal ultrasonography in cases of a fertility work-up (hysterosalpingo-foam sonography [HyFoSy]).