This article covers state-of-the-art instruments and devices specially designated for endoscopic ear surgery. New technologies stimulate the creation of special endoscopic equipment and microinstruments specially designed to satisfy the exclusive requirements of endoscopic ear surgery, which contribute to the progress of the procedure. The article presents the advantages and disadvantages of working with ear endoscopes and details the advances in equipment used in ear endoscopies. New instruments specially modified for working with angled-vision endoscopes and considerations of the surgeon’s use of them are discussed.
Key points
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The operating microscope requires wide viewing portals for adequate illumination and visualization of the operative field, contrary to the endoscope, which provides direct vision with illumination to the target field, thus avoiding the need for extra exposure and extra drilling.
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When planning an exclusive endoscopic ear surgery, still the microscope is an essential part of the surgical setting making it ready to use whenever needed. Combining the attributes of microscope and endoscope during surgery is the most efficacious approach.
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Cholesteatoma resection is considered complete only after a final survey with the angled endoscopes is completed, confirming absence of pathologic conditions from all hidden recesses.
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The principal advantage of aspiration instruments is the ability to perform dissection and aspiration maneuvers at the same time overcoming the impact of operating with one hand as imposed by otoendoscopic surgery. The main limit of instruments with suction channels is the possibility of occlusion caused by detritus aspirated during dissection.
Introduction
This article covers state-of-the-art devices and instruments specially designated for endoscopic ear surgery. New technologies have stimulated the creation of special endoscopic equipment and microinstruments specially designed to satisfy the exclusive requirements of endoscopic ear surgery, which in turn contributes to the progress of the specialty. In addition, these new, specially designed instruments have expanded the indications and refined the surgical skills for this surgery. This, in turn, allows better control of pathological conditions and permits access to previously unreachable or difficult to reach anatomic recesses (ie, sinus tympani, facial recess, and anterior epitympanic recess).
The operating room for ear surgery should contain state-of-the-art instrumentation. The surgeon should be in a comfortable working position during the prolonged holding of the endoscope, which is mounted with the endoscopic video camera. Even when planning an exclusive endoscopic ear surgery, the microscope is an essential part of the surgical setting. The microscope should be supplied with a built-in high-definition camera that allows continuous documentation in parallel with the endoscopic surgery performed, all through a high-definition video monitor. The presence of continuous video monitoring enables the anesthesiologist, the scrub nurse, and others to observe and follow the proceedings of the operation. Recordings can also be used for teaching purposes.
The patient is placed supine on the operating room table in the normal otologic position. The microscope is placed in the sterile field ready to be used whenever needed. The endoscopic tower is placed directly facing the surgeon while the monitor is level with the surgeon’s eyes. Because the surgeon is not looking down into the eyepiece of the endoscope and, instead, is looking directly forward at the video screen, proper alignment of these components is essential to keep the surgeon orientated to the surgical field and to ensure a comfortable working position.
Introduction
This article covers state-of-the-art devices and instruments specially designated for endoscopic ear surgery. New technologies have stimulated the creation of special endoscopic equipment and microinstruments specially designed to satisfy the exclusive requirements of endoscopic ear surgery, which in turn contributes to the progress of the specialty. In addition, these new, specially designed instruments have expanded the indications and refined the surgical skills for this surgery. This, in turn, allows better control of pathological conditions and permits access to previously unreachable or difficult to reach anatomic recesses (ie, sinus tympani, facial recess, and anterior epitympanic recess).
The operating room for ear surgery should contain state-of-the-art instrumentation. The surgeon should be in a comfortable working position during the prolonged holding of the endoscope, which is mounted with the endoscopic video camera. Even when planning an exclusive endoscopic ear surgery, the microscope is an essential part of the surgical setting. The microscope should be supplied with a built-in high-definition camera that allows continuous documentation in parallel with the endoscopic surgery performed, all through a high-definition video monitor. The presence of continuous video monitoring enables the anesthesiologist, the scrub nurse, and others to observe and follow the proceedings of the operation. Recordings can also be used for teaching purposes.
The patient is placed supine on the operating room table in the normal otologic position. The microscope is placed in the sterile field ready to be used whenever needed. The endoscopic tower is placed directly facing the surgeon while the monitor is level with the surgeon’s eyes. Because the surgeon is not looking down into the eyepiece of the endoscope and, instead, is looking directly forward at the video screen, proper alignment of these components is essential to keep the surgeon orientated to the surgical field and to ensure a comfortable working position.
Standard instruments for microscopic ear surgery
Besides the standard instruments required for the approach through the soft tissue (eg, scalpels, forceps, and monopolar and bipolar diathermy), specific otologic instruments ( Fig. 1 ) include
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Self-retaining mastoid retractors
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Instruments for bone work: microdrill, micromotor handles straight and curved, set of different-sized tungsten cutting burrs, and diamond burrs
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Irrigation and suction instruments
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Soft tissue dissectors, large and small scissors, toothed and untoothed forceps, periosteal raspatory.
In general, a full set of microsurgical instruments is required, which are very familiar to practicing otologists:
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Microforceps (microcup and microalligator); microscissors, delicate straight and curved; microhooks of different angles and lengths; needles; elevators, knives of different sizes and shapes (eg, round cutting knife); Plester vertical cutting knife; sickle knives of variable curvatures; Rosen elevator; House curettes, large and small; and so forth
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Suckers and suction-irrigation of different sizes
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Fine suction tips and adaptors with control hole.
Endoscopes and special instruments for endoscopic ear surgery
Ear Endoscopes
Endoscopes have proved increasing benefit in ear surgery. Incorporating the endoscope into the surgical armamentarium in otology has contributed much to the concept of minimally invasive surgery. This is because the operating microscope requires wide viewing portals for adequate illumination and visualization of the operative field, contrary to endoscope, which provides direct vision with illumination to the target field, thus avoiding the need for extra exposure and extra drilling.
Endoscopes have many proven advantages over the microscope, including
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Wider angle of view
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Better visualization of structures that are parallel to the axis of the microscope
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Visualization of deep recesses and hidden structures (ie, around the corner)
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Ability to visualize beyond the shaft of the surgical instruments.
On the other hand, several disadvantages of endoscopes include
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Loss of depth perception and binocular vision
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The inevitable one-handed surgical technique involved
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Need for a strictly bloodless field (meticulous attention to hemostasis is essential)
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Fogging and smearing of the tip of the endoscope
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The mandatory need for reliable physician training
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The cost of equipment.
Rigid Endoscopes
The design of the Hopkins rod-lens system was developed to yield endoscopes of variable length, diameters, and angles of view. The rigid endoscopes commonly used for ear surgery are 2.7 mm, 3 mm, or 4 mm in diameter. All the new endoscopes are now autoclavable. The working lengths are 18 cm, 11 cm, and 6 cm. The larger the diameter, the better the image displays and the more light it can transmit to the operative field. The 0° and 30° angled scopes are the most commonly used, followed by the 45°. Endoscopes with a greater angle, such as the 70°, are difficult and disorienting to work with and are only used for inspection in limited spots, such as the sinus tympani, which may lie very deep in 20% of cases ( Fig. 2 ). Recently, new developments in optics have led to the creation of a new generation of wide-angled endoscopes with smaller diameters that provide better quality images.
The 0° endoscope provides all of the imaging needed to perform the major steps of any endoscopic operation. The optics allow near-complete exposure of most of the field and pathologic condition. However, the extent of visualization under the 0° endoscope is limited by its optical capabilities. The distal lens of the otoscopes must be cleaned with an antifog solution before each application.
Practically, in cholesteatoma surgery, once cholesteatoma resection under the 0° endoscope is deemed complete, it is replaced with the angled 30° or 45° endoscopes. By advancing the angled endoscope and rotating it in clockwise and counterclockwise directions along its longitudinal axis, all middle ear recesses are visualized and any hidden pathologic conditions can be detected and removed. Cholesteatoma resection is considered complete only after a final survey with the angled endoscopes is completed, confirming absence of pathologic condition. A 70° endoscope may also be used in this examination; however, in most cases, the information obtained by the 30° or 45° lens is sufficient to identify any residual pathologic condition.
Instruments
The development of special equipment and instruments for endoscopic ear surgery is based on the International Working Group on Endoscopic Ear Surgery (IWGEES) experience of more than 15 years performing endoscope-assisted and/or exclusive endoscopic ear surgery. Adapting and refining regular microinstruments to include longer, more slender shafts with single or double curvatures and smaller microtips have been essential for endoscopic ear surgery.
Major innovation of highly sophisticated technologies such as xenon light sources, high-resolution cameras and monitors, digital processors, documentation, and lens irrigation systems have complemented the advances in endoscopic technology and stimulated the creation of dedicated endoscopic equipment and microinstruments specially designed to fulfill the unique requirements of endoscopic ear surgery.
Practically, endoscope-assisted and fully endoscopic ear surgery require the standard otologic microinstruments, familiar and used by any otologist, and the specially modified and newly designed endoscopic ear surgery instruments. A basic set of instruments, based on the IWGEES experience, used exclusively for endoscopic ear surgery is now available. It includes sets of curved shaft dissectors and sharp hooks, sets of curved suction cannulae, sets of curved curettes, and sets of curved cupped forceps with 10 cm working length. Most recent are the newly designed instruments incorporating suction into the shaft, facilitating dissection with one hand while the other hand holds the endoscope. The best example of this is the round cutting knife with suction shaft ( Fig. 3 ).
