Equipment and Supplies

Malcolm G. Munro MD, FRCSC, FACOG
KEY POINTS:
  • Hysteroscopic systems can considered to be either flexible or rigid, with current flexible devices suitable only for visualization of the cervical canal and endometrial cavity.
  • Operating hysteroscopic systems include an instrument channel that is generally 3, 5 or 7 French in diameter although diameters up to 9 Fr are available.
  • The resectoscope is a rigid endoscopic instrument designed to provide hysteroscopic direction of radiofrequency (RF) cutting, vaporization or electrodesiccation designed either as a bipolar or monopolar system.
  • Hysteroscopic distension media comprise CO2 gas and a spectrum of fluid media types. CO2 systems are useful only for visualization and require a specially designed insufflator. Simple, gravity fed fluid systems are adequate for diagnostic hysteroscopy but for many operative procedures a fluid management system is necessary.
  • The operative field (endometrial cavity & cervical canal) must be illuminated either with a source integrated into the hysteroscopic system or a remote light source of sufficient power and fiberoptic light cable.
  • If RF electrosurgery is to be performed, an electrosurgical generator appropriate for the instruments is mandatory as are appropriate connection cables, and, if monopolar systems are used, a dispersive electrode.
  • If electromechanical morcellation systems are to be used, then appropriate and usually proprietary controller units must be available along with the matching footpedals, hysteroscope and single or multi use probes as necessary.
ENDOSCOPES and SHEATHS
Hysteroscopes

Hysteroscopes are available in two basic types—flexible and rigid. Each have advantages and disadvantages but our recommendation for programs is that they base their programs on rigid hysteroscopic systems.

The typical rigid hysteroscope comprises an eyepiece, an intervening shaft that is typically about 30 cm long with a lens located at the distal tip. Integrated into the design are a series of lenses for transmitting the image from the distal lens to the eyepiece and a set of fiberoptic bundles that serve to transmit light from an external source along the shaft to the distal end of the device. Channels for transporting distending media into and from the endometrial cavity or to allow the insertion of instrumentation for intrauterine manipulation are generally located in a separate sheath that fits around the hysteroscope thereby forming a hysteroscopic assembly (Figure). Recent developments based on light emitting diode (LED) technology and image sensors such as complimentary metal-oxide semiconductor (CMOS) “chips” have allowed for dramatic changes in hysteroscopic design. The CMOS sensors replace the lenses and eyepieces and the LED technology replaces the fiberoptic fibers and the cold light source and cables. While the digital transition will no doubt continue, the majority of hysteroscopes are of the traditional rod lens and fiberoptic variety. This means that the hysteroscopy center must have the requisite light sources and cables discussed subsequently.
Flexible hysteroscopes differ from rigid systems in that they are self-contained without the need for a sheath to allow for delivery of distending media and consequently are generally of smaller diameter. The design integrates one set of fiberoptic bundles for light transmission while the other is linked to the distal lens to allow for visualization of the operative field. The channel for delivery of distension media typically doubles as a portal for the insertion of operating instruments, a circumstance that can adversely affect maintenance of distention. 
Flexible hysteroscopic systems are “steerable”, possessing a user-managed deflectable tip that facilitates insertion into and through a curvilinear cervical canal. The ability to manipulate the tip provides for angled viewing of aspects of the endometrial cavity that might not be visible with a 0ᴼ lens.  some of the advantages of flexible hysteroscopes, and especially for the hysteroscopic surgeon, there are several reasons for selecting rigid systems.. First of all, the fiberoptic bundles of a flexible hysteroscope generally have lower resolution than that of rigid instruments with rod lenses. Second, the operative channels of current flexible hysteroscopes are generally too small for useful operative instruments, so they are primarily used for diagnostic imaging. Flexible hysteroscopes are not designed with the continuous flow design necessary to clear the operative field. As a result, flexible hysteroscopes are generally best suited for simple diagnostic visualization procedures. (Figure) 
Rigid hysteroscopes provide are more durable and provide superior image quality. Available rigid hysteroscopes range from 2 to 4 mm in outside diameter (OD) and have a fixed viewing angle generally available 0ᴼ, 12 -15ᴼ and 25 – 30ᴼ designs angled lenses being referred to as “fore-oblique” (Figure). The angle of the fore-oblique lens is, by convention, directed away from the position of the “light post” located on the proximal end of the device and used to connect the endoscope to the light cable. The choice of viewing angle for a given case is a matter of surgeon preference and the procedure to be performed. The 0ᴼ hysteroscopes allow easy orientation to the image on the screen since it reflects that of normal vision but it doesn’t allow for any angled viewing within the endometrial cavity such as into the cornual areas or for different perspectives on targeted lesions. 
Sheaths
The sheaths for rigid endoscopes include the conduits required for delivery and outflow of distension media and for the placement of operative instruments. So-called “diagnostic” sheaths may have a single channel for instillation of distention media, but we suggest that programs acquire only sheaths with at least two channels because continuous inflow and outflow of fluid distention media is associated with improved visualization. Continuous flow systems with an additional instrument channel are essential for any complex operative hysteroscopic procedure (Figure). While these features add to the overall diameter of the instrument inserted through the cervical canal, these additional features are necessary for a safe and effective procedure.
LIGHT SOURCES and CABLES
Requirements for light vary with the endoscope, the quality and sensitivity of the camera sensor, the volume of the endometrial cavity and the presence of blood or dark tissue, each of which absorb the light. For most cameras and endoscopes there must be at least 150 watts of power for diagnostic procedures and preferably 250 watts or more operative procedures, particularly those on larger cavities(2). 
The quality of the light delivered to the operative field is not only dependent on the wattage of the light source but also the diameter, quality and integrity of the fiberoptic cable. There has been a tendency to move to narrow caliber cables, 4-5 mm in diameter (3-4 mm diameter fiber bundles) which deteriorate more quickly below the required illumination as fibers break. Consequently, we think that it makes more sense to use larger caliber 8-9 mm (5 mm diameter fiber bundles) which are slightly more difficult to manipulate but which last longer before their light transmission capabilities deteriorate. This is a time to make the point that maintaining these cables is important – sharply bending fiber bundles results in breakage and deteriorated performance.  
Safe and effective hysteroscopy requires that there is adequate illumination of the endometrial cavity. For traditional hysteroscopes, the required light originates from a remote source and is delivered via a specially designed fluid or fiberoptic cable to the ‘light post” on the hysteroscope. These cables and light posts have a variety of proprietary designs although most hysteroscopes have integrated adapters that allow configuration for different cables (Figure X). 
VIDEO IMAGING
Whereas diagnostic hysteroscopy can be performed with direct visualization – the naked eye to the eyepiece - it is advisable to use video guidance, at least when procedures are prolonged or require the use of two hands on the instrumentation. There are other advantages to video imaging, including the ability of the support team to view and anticipate the needs of the surgeon and, when performed under no or local anesthesia, video imaging allows the patient to view of the operative field simultaneously with the surgeon. In academic environments, video monitoring allows trainees to visualize the procedures in a way that is not possible without a medical camera. Furthermore, video imaging allows a supervising surgeon the opportunity to provide guidance to the trainee as he or she performs surgical procedures. This approach not only enhances the quality of training but also the safety of the procedure. Video imaging also provides the opportunity for recording of findings and procedures that can be edited for training purposes, or for the use of the patient and her other providers.
Medical grade endoscopic cameras typically comprise two distinct parts; the “sensor” which is effectively a CMOS chip attached to the hysteroscope’s eyepiece by a “C” coupler, and the base or controller module. The base module receives the signal via a connecting cable and processes the data so that an image can be visualized on a monitor or recorded as a still or video file. The previously described hysteroscopes designed with integrated imaging sensors and LED (light emitting diode) lighting effectively bypass the need separate illumination systems and a detachable camera allowing the imaging signal to go straight to the monitor or image storage system. Monitors are identical to those used for commercial and home use and should match the resolution of the imaging system. While high definition video is likely superior to lower resolution systems, it is unlikely that “4 K” systems add to procedure imaging quality and may add more to the cost of acquisition. 
SYSTEMS FOR UTERINE DISTENTION and MEDIA MANAGEMENT
Distention of the endometrial cavity with a clear and transparent media is a predicate to the creation of the viewing space in the endometrial cavity required for all hysteroscopic procedures. The media used for this purpose may be either gaseous CO2 or one of a spectrum of liquids. Both CO2 and high viscosity fluid media are less frequently used today. Carbon dioxide gas requires the use of a gaseous resorvoir, a specially designed low pressure insufflator, often referred to as a ‘Hysteroflator®’ and, because of the inability to clear the surgical field is unsuitable for operative hysteroscopy. The low viscosity fluids contain either electrolytes, most commonly 0.9% normal saline, or are electrolyte free, including solutions such as dextrose in water and those increase osmolality containing sugars such as 3% glycine, 1.5% sorbitol and 5% mannitol. 
There three components of fluid management include infusion, removal and quantification of fluid balance sometimes called “intravasation”. For diagnosis, simple infusion systems can be created using a syringe connected to the hysteroscopic system, usually through a suitable port on the sheath. Unfortunately, such simple systems may be ineffective for maintaining adequate dilation, particularly for procedures or in a large volume endometrial cavity. Consequently gravity-based systems that use an a “IV Pole” to hang a bag of solution at prescribed heights and connected to the hysteroscopic system with appropriate tubing (generally wide “C-tubing”) are effective. The pressure in the system can be augmented with an inflatable pressure cuff placed around the bag. The next level is the use of any of a variety of infusion pumps but the safest are those that are designed to maintain a preset intrauterine pressure, reducing the rate of flow when the preset threshold is reached. 
For simple diagnostic systems measurement of outflow is challenging since there is no dedicated outflow port. With such a device, removing fluid from the cavity may occur via an over dilated cervix, by disconnecting the infusion tubing or by completely removing the hysteroscopic system. The process is made more feasible and accurate with a dedicated outflow port. With such a design, outflow tubing is attached and the media directed either passively into a receptacle or bucket, or, attached to low-pressure suction to facilitate removal.
The systemic absorption of large volumes of distending media poses a hazard to electrolyte balance with electrolyte free solutions and to cardiac overload with any type of media. Consequently, there exist a number of fluid management systems designed to continuously monitor both distension media inflow and outflow in a way that allows for “real-time” monitoring of fluid balance. Systems either measure the weight of infused and collected fluid, converting these calculations to estimated volume, or actually measure the volume of the infused fluid compared to the weight of the collected outflow fluid. Most systems provide a user adjustable alarm that sounds when a preset discrepancy has occurred. Many operating rooms require the use of a fluid management system to enhance patient safety and these systems are strongly recommended for hysteroscopic surgery that crosses the basal layer of the endometrium.
MECHANICAL INSTRUMENTS FOR TRANSECTION AND TISSUE REMOVAL
Performance of hysteroscopic surgery requires some combination of incision, excision and destruction of intrauterine tissue performed under direct visual guidance. The instruments designed for this purpose are either mechanical or based on radiofrequency (RF) electrical energy. Laser energy, introduced in the latter part of the 20th century has no real place in contemporary hysteroscopic surgery. 
The mechanical instruments most commonly available for use through the operating channel of a hysteroscopic sheath include biopsy forceps, grasping forceps, and scissors. It is necessary that such instruments are both narrow and flexible enough to navigate a 1- to 3-mm (3 – 7 French or Fr) diameter operating channel (Figure, Video). While the narrow diameter of these devices permits surgery in the cervical canal or endometrial cavity, their small size and delicate construction limit their capabilities and especially endurance. Surgeons and staff should be trained in the careful use of these delicate instruments in a way that enhances their durability.
When setting up a program it is recommended that there be a supply of hysteroscopic scissors and biopsy and grasping instruments. Because these relatively delicate instruments are fragile it is important to have adequate redundancy, but also to train the users in their proper use, in a way that minimizes stress on their structural integrity.
ELECTROSURGICAL INSTRUMENTS and SUPPLIES
For hysteroscopic surgery, radiofrequency (RF) electrical energy is delivered to the endometrial cavity either via a resectoscope or using narrow monopolar or bipolar instruments passed through the operative channel of a hysteroscopic sheath. These RF instruments can be manipulated to cut, vaporize or coagulate tissue within the endometrial cavity or the cervical canal). An intimate understanding of the principles of RF electrosurgery is mandatory for safe and effective use of these instruments.
The gynecologic resectoscope a RF based device that is identical that used by urologists for surgery in the urethra and bladder (Figure). By extending and retracting the “working element,” any one of a variety of electrode designs can be manipulated within the endometrial cavity to create a tissue effect – transection, electrocoagulation, vaporization. Vaporization of tissue requires specially designed electrodes and an electrosurgical generator that can deliver high wattage current. Whereas all RF electrosurgery requires two electrical "poles", resectoscopes can be either monopolar or bipolar in design. 
Monopolar resectoscopes require that electrolyte free distension media be used to minimize dispersion of the electrical current and thereby facilitate concentration of the energy on the target tissue. Monopolar resectoscopes are prone to inducing electrosurgical injury to the vagina and vulva related to capacitive coupling to the outer sheath of the resectoscope(3). Furthermore, since the monopolar intrauterine instruments require the use of electrolyte-free media, the potential for hypervolemia secondary to excess systemic absorption may be further complicated by hyponatremia(4).
For new programs at least, we would recommend starting with bipolar RF instrumentation, including bipolar resectoscopes. These instruments have been developed to reduce the risks associated with monopolar systems that include those related to current diversion and the hyponatremia that can be associated with systemic absorption of distension media(5, 6). While the mechanical aspects of the systems look similar to monopolar instruments the key difference in the design is such that both the “active” and dispersive electrode are integrated into the device. This allows the circuit to be completed, not dispersed in electrolyte rich media such as normal saline while eliminating the risk of current diversion.
MECHANICAL INSTRUMENTS  for SPECIMEN EXTRACTION
Some hysteroscopic surgical procedures require that tissue be removed from the endometrial cavity or cervical canal. The instrumentation used for specimen extraction comprises biopsy forceps, forceps or tenaculums used for grasping and extracting tissue specimens and devices designed to mechanically morcellate and, in some instances, automatically extract the tissue. The typical biopsy forceps have a articulated cup-like design that allows the surgeon to grasp visually targeted, albeit tiny tissue specimens, and then transect and extract them through the operating channel of a sheath. Hysteroscopic grasping instruments include a variety of tip designs for securing under direct endooscopic vision, detached specimens that are exemplified by polyps or small leiomyomas and then remove them from the endometrial cavity by withdrawing the entire hysteroscope-sheath assembly.
Another instrument created for tissue extraction is the Corson grasping designed with a distal articulation that allows insertion into the endometrial cavity and unimpeded opening of the jaws in a way that facilitates grasping and removal of a free tissue specimen such as a leiomyoma or larger polyp. Despite the blunt design of this instrument, blind manipulation may result in perforation so transabdominal ultrasound should, wherever possible, be used to direct its use for grasping and extracting tissue. 
Another efficient mechanical approach is the electromechanical morcellating systems that have a distal side aperture and automated oscillating blade that sequentially slices portions of a specimen that are then aspirated into an inline capture system (7, 8). Such systems are somewhat expensive because there are relatively costly single use items. However, if they are used in an office or clinic environment, the money saved by avoiding the operating room costs generally results in a less costly procedure. 
RECOMMENDED EQUIPMENT
The recommended equipment described is categorized by the degree of case complexity anticipated in your program. This is a synthesis of surgeon training and ability, the available resources and the regulatory environment in your center. 
Diagnostic & Minor Procedure Only Program
Visualization, Directed Biopsy, IUD Removal, Minor Adhesion Transection, Small Polyp (<1 cm) Removal
Category Item Comment
Endoscopes 12ᴼ Rod Lens Hysteroscopes 2.9 - 3 mm OD
30ᴼ Rod Lens Hysteroscopes 2.9 - 3 mm OD
Sheaths 4-4.5 mm OD Continuous Flow For diagnosis only, instrument channel 3 Fr
5-5.5 mm OD Continuous Flow Good standard system
6-6.5 mm OD Contiuous Flow Useful for patulous cervis to help establish and maintain dissension
Light Sources 250-300 Watt Output Cold Light Source Unless purchased Distal CMOS/LED System
Light Cables 5 mm bundles; 8-9 mm OD Ensure appropriate adapters to endoscopes
Video Imaging Medical Grade HD Camera with C-Coupler Includes central unit
HD Monitor 22-32 inch diagonal Commercial similar to "medical grade"
Image Recording System Stills to coordinate with electronic record
Distension Media Management IV Pole
C-Tubing Facilitates adequate flow
Transection and Tissue Removal Hysteroscopic Scissors 5 Fr Multi use but fragile
Hysteroscopic Biopsy Forceps 5 Fr Multi use but fragile
Hysteroscopic Grasping Forceps 5 Fr Multi use but fragile
Hysteroscopic Tenaculum 5 Fr Multi use but fragile
Intermediate Complexity Procedure Program (Diagnostic & Minor +)
Polyp Removal ≥1 cm; FIGO Type 0 and 1 ≤2 cm Removal; Metroplasty U2-C0-C0 Anomalies; Moderate Intrauterine Adhesions
Category Item Comment
Integrated System Electromechanical Morcellator Includes endoscope and instrument channel
Distension Media Management Fluid Management System Inflow, outflow and calculates fluid deficit
Electrosurgical Bipolar Needle - 5 Fr Single or multiple use
Bipolar Ball - 5 Fr Single or multiple use
Bipolar Vaporizing 5 Fr Single or multiple use
Electrosurgical Unit (for Bipolar System) Capital item
Manual Tissue Extraction Corson Forceps 7 mm Capital item
Corson Forceps 9 mm Capital item
Corson Forceps 11 mm Capital item
Electromechanical System
Electromechanical System Controller
High Complexity Procedure Program (Intermediate Complexity +)
FIGO Type 0 & 1 >2 cm and Type 2; Metroplasty U2-C1; Severe Intrauterine Adhesions
Category Item Comment
Electrosurgical RF Resectoscope Strongly prefer bipolar system
Resectoscope Vaporizing Electrode (Bipolar) Single use
Resectoscope Coagulation Electrode (Bipolar) Single Use
Ultrasound Abdominal and Vaginal Transducers In room
REFERENCES