1. Introduction
Endoscopic ear surgery (EES) with the wide viewing angle of modern endoscopes (Fig. 1), overcomes many of the limitations of the traditional microscopic approaches to middle ear and canal disease, some of which mandated postauricular approaches in the past. A very broad range of otologic disease can now be successfully managed with the endoscope (Box 1). This review serves as a primer for the otologist embarking on EES and discusses many concepts essential to safe and successful adoption of EES such as learning theory, the optical chain and instrumentation. A broad understanding of endoscopic, fiberoptic, camera and screen technology is essential to optimizing the endoscopic view as well as ensuring patient safety.
2. Modern learning theory and its application to EES
Certain concepts from modern learning theory are relevant to any surgeon, from junior resident to experienced consultant, looking to introduce a new technique into their practice. The surgeon’s emotional state and cognitive bias impact on learning at the time new information is received. With respect to EES, cognitive bias is best exemplified by the way traditional microscopic methods have been used in surgical scenarios in the past. Bjork (1994) describes several “desirable difficulties” that enhance the long-term uptake of a new operative technique:
- Varied conditions of learning – in this instance moving from standing to sitting and interspersing different first cases, enhances long term hand eye co-ordination.
- Distributed sessions – an inter-training interval of approximately 7 days is ideal, not block learning (such as repeated 2- day intensive courses).
- Self-testing – regular review of the relevant anatomy is important to establishing the long-term memory.
2.1. Learning EES in residency
With less experience, residents generally bring low cognitive bias (as to the benefits of microscopic ear surgery) and a more erratic emotional state to the learning environment of EES. Ideally, residents will have been through a period of autonomous scope holding prior to progressing onto live surgery. Most often this can be achieved through cadaver or 3D printed temporal bone courses. Today’s residents are frequently adept with scope handling through their experience with Functional Endoscopic Sinus Surgery. Knowledge of anatomy is critical, and review of anatomy in standard texts, as well as through focussed endoscopic cadaveric dissections online (http://www.sydneyearendoscopy.com) is of paramount importance. A stepwise training schedule using operant conditioning in the form of relatively neutral click prompts has been demonstrated to show uniform improvement in cohorts of orthopaedic surgical residents and medical students (Levy et al., 2016). This method could be applied to EES resident training (Box 2). 2.2. Learning as an established surgeon In contrast to residents, established surgeons generally bring a high cognitive bias (regarding the benefits of traditional microscopic methods) and a superior ability to control their emotional state than residents. Learning for experienced surgeons commences with prereading, watching anatomy and surgical videos online (http://www.sydneyearendoscopy.com). The established surgeon should then attend at least one course where the endoscopic approach is taught and begin soon after with a step wise progression of cases (see below). Prior to progression toward more advanced techniques, the established surgeon should consider visiting another surgeon familiar with EES methods or asking such a surgeon to attend their operating sessions as a mentor. Figs. 6 and 7 compare the captured images of a left stapedectomy with microscope and endoscope.