# The Role of Powered Surgical Instruments in Ear Surgery: An Acoustical Blessing or a Curse?
## 3 History of Otological Surgical Instruments
### Ultrasonic Devices  
A new type of device technology began to make an appearance in the medical literature around the 1970s: ultrasonic devices. Broadly speaking, three types of ultrasonic devices used in surgery have appeared on the market: cavitation ultrasonic aspirators or CUSA devices; piezoelectric devices; and ultrasonic aspirators equipped with longitudinal and torsional oscillation.  
A CUSA instrument selectively targets the fluid in soft tissue such as tumors, but leaves hard tissue such as bone untouched [20]. CUSAs are quite frequently used in neurosurgery [21] and renal surgery [22] and have enabled surgeons in these fields to remove tumor tissue located in areas with little room for error with less possibility of damaging anatomical structures in comparison to electric drills.  
Piezoelectric devices are another type of ultrasonic device that can cut both bone and soft tissue depending on the frequency setting [23]. These devices are another example of borrowing a tool primarily used in dental surgery and expanding its reach into a wide variety of fields, including craniofacial surgery, to perform osteotomies [24] and ear surgery to perform  
Figure 2: (**a**) Surgical instruments for trepenning. Engraving with etching by [PERSON]. Credit: Wellcome Collection. CC BY (**b**) Tools for mastoidectomy [18]. (**c**) Visao® High-Speed Otologic Drill, Medtronic, Shinagawa, Tokyo, Japan. (**d**) Sonopet® Omni, (model UST-2001 Ultrasonic Surgical Aspirator, Stryker Corporation, Kalamazoo, Michigan, USA).  
mastoidectomies [25]. However, some surgeons have found that piezoelectric devices compare unfavorably to electric drills in terms of bone cutting power and speed [9].  
A third type of ultrasonic device offers the reverse of the CUSA by targeting hard tissue such as bone and leaving soft tissue relatively untouched. Both the CUSA and this new type of ultrasonic aspirator that removes only bone are often referred to in the literature as an ultrasonic bone curette (UBC) because they can both use the same handpiece to which a specialized tip is attached. These third types of ultrasonic aspirators remove bone using a longitudinal oscillation (L mode) or longitudinal and torsional oscillation (LT mode) to emulsify bone and these L mode/LT mode UBCs have been used in fields such as neurosurgery [26], paranasal sinus surgery [27], maxillofacial surgery [28], and spinal surgery [29].  
Our original paper on powered TEES referred to the ultrasonic aspirator which we used as a Sonopet(r) UBC [17]. However, this ultrasonic aspirator that we used and still use today, emerged on the market in the early 2000s and has passed through a number of companies [30]. This ultrasonic aspirator is today more properly called the Sonopet(r) Omni and uses an H101 tip (model UST-2001 Ultrasonic Surgical Aspirator, Stryker Corporation, Kalamazoo, Michigan, USA) (Figure 3).  
It is the Sonopet(r) Omni together with its H101 tip that has allowed us to perform powered TEES. The ability of this Sonopet(r) Omni to target bone while generally avoiding soft tissue made it the perfect tool for working within the narrow confines of the external auditory canal and for removing bone from the ear canal. In addition, the Sonopet(r) Omni not only removes bone, but also has irrigation and aspiration functions that were critical in opening the door to powered TEES, as will be described below. However, little information has been reported on the safety of the Sonopet(r) Omni in terms of noise levels and vibrations [15], which will also be discussed below.