Exoscope and Personal Protective Equipment Use for Otologic Surgery in the Era of COVID‐19

Abstract

The SARS-CoV-2 virus (COVID-19) and subsequent pandemic have rapidly changed how physicians, specifically otolaryngologists, think about personal protective equipment (PPE) and personal safety in the operating room. Since the Wuhan outbreak, high rates of nosocomial spread were seen among otolaryngologists due to the high viral load in the upper respiratory tract.1-3 The true infectious risk of various procedures is still unknown. Consequently, the definition of “proper PPE” for each procedure is debated. Many otolaryngology procedures are aerosol generating and require an N95 mask and face protection, at a minimum. Some procedures warrant powered air-purifying respirators (PAPRs).4 Transmastoid and lateral skull base surgical procedures are particularly high risk for several reasons. First, the lining of the middle ear is continuous with the nasopharynx, the site of highest COVID-19 viral concentration.3 Prior studies detected a variety of respiratory viruses in the middle ear in the setting of upper respiratory infections.5,6 It is therefore reasonable to assume that COVID-19 is present in the middle ear and mastoid. Second, otologic surgery often demands the use of high-powered drills and irrigation, which may readily aerosolize the virus. Third, using the microscope with the appropriate PPE is challenging. In particular, it is difficult to look through the eyepiece of a microscope while wearing goggles, a face shield, or a PAPR hood. The use of exoscopes has recently gained traction in otologic/neurotologic surgery.7,8 In the current article, we describe our use of the exoscope as well as a novel draping method to safely perform a high-risk, aerosol-generating otologic procedure. For this work, we obtained exempt status from the NYU Langone Health Institutional Review Board. The technique with the exoscope accommodated full use of PPE without compromising surgical visualization, patient outcomes, or surgical time. Therefore, it may serve as a potential solution for performing otologic surgery in the era of COVID-19. A 69-year-old man who had widely infiltrative T4aN3bM0 parotid carcinoma with invasion of the facial nerve underwent wide local excision, mastoidectomy with decompression of the facial nerve, and reconstruction with anterolateral thigh free flap and nerve grafting. The patient had a negative preoperative COVID-19 test result. All members of the operating team utilized N95 masks and 3-dimensional (3D) eye shields with routine patient draping. A plastic sterile drape (3M Steri-Drape 1015) with an adhesive end was applied circumferentially around the normally draped 4K 3D exoscope (Olympus ORBEYE) and enclosed around the sterile field to create a small tent (Figure 1). The surgeon’s hands were placed as usual, in the field beneath the tent, with the drapes acting as a physical barrier to spray, aerosolized particles, and bone dust from the drilling. Instrument exchanges were easily performed under and around the tented drape. Of note, the surgical team initially used the 3D glasses beneath a face shield; however, the curved shape of the face shield resulted in subtle refraction of the image reaching the polarized glasses, obscuring the 3D visualization. As the 3D glasses themselves provided wide eye protection very similar to disposable goggles, they were used as the sole eye protection. While the true risk of transmission of COVID-19 during otologic surgery is currently unknown, transmastoid procedures are considered high risk. Therefore, proper PPE and overall safety of all team members in the operating room remain paramount. An exoscope system allows the surgeon the option of wearing many forms of PPE with a comfortable view of the operative field by utilizing a custom draping “tent technique” as a barrier. The barrier method has been discussed as a possible solution for intubations as well as nasal endoscopy.9,10 We found a similar anecdotal reduction in macroscopic dispersal of fluid and dust using this method. Additionally, we identified similar advantages described by others implementing the exoscope for otologic surgery: the learning curve was minimal; the surgeon felt ergonomically better positioned; and surgical time was roughly equivalent to use of a traditional microscope. Exoscope with barrier tent. (A) After standard draping of the exoscope, a sterile drape with adhesive was circumferentially attached to the camera head and draped onto the operative field to create a barrier tent without obscuring the camera views. A member of the surgical team is wearing full personal protective equipment, including an N95 respirator beneath a standard surgical mask with the 3-dimensional glasses as eye protection. (B) The surgeon’s arms can rest in typical position beneath the barrier tent, and instrumentation such as a high-powered drill and suction is carefully passed by the surgical technician beneath the tent from the opposite side of the table. The large 3-dimensional monitor is visible to the surgical team and all operating room staff. While this report focuses on exoscope use, we believe that a draping barrier can certainly be applied to traditional microscopes and customized with available equipment and may serve to protect all operating room staff. When debriefing with the surgical team, we felt that there were potential areas for improvement. For example, a metal support (Leyla holding rod, or a “Christmas tree”) could be placed on the opposite end of the table and the clear drapes secured from the exoscope (or microscope) head to the raised bar. The drape should be pulled taut and positioned to avoid interference with the lens of the scope. The depth perception created by this exoscope relies on the use of polarized 3D glasses. Attempts to use these beneath face shields reduced the 3D depth perception, likely by obscuring the image reaching the polarized filters. Further experimentation with the system revealed that the easily deconstructed glasses placed on the outside of the face shield produced an excellent view (Figure 2). This practical arrangement is likely also suitable for goggles or PAPR shields, similar to the existing clip-on style of 3D glasses for prescription glasses. As health care teams and otolaryngologists around the world navigate methods to safely resume care of patients, the high incidence of asymptomatic patients with SARS-CoV-2 combined with currently imperfect available testing methods emphasizes the importance of taking available precautions. Transmastoid exoscope visualization may be combined with endoscopic ear transcanal approaches to allow surgeons broader use of PPE. The use of the exoscope and alternative draping techniques may serve to improve safety while providing comparable views and surgical outcomes in otologic surgery, as well as other otolaryngologic procedures. Three-dimensional (3D) glasses and personal protective equipment. (A) Initial attempts at using the polarized 3D glasses beneath a curved clear plastic face shield reduced the integrity of the visualized 4K 3D images on the screen. (B) Further trials found that the glasses are easily disassembled and that the polarized filter element placed on the outside surface of the face shield produced excellent visualization. Steven A. Gordon, surgeon, lead author, manuscript writer; Nicholas L. Deep, co–lead editor, surgeon, developed Figure 1, assistant writer; Daniel Jethanamest, co–lead editor, surgeon, developed Figure 2. Competing interests: None. Sponsorships: None. Funding source: None.

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