CIC hearing aids require ear impressions of significantly greater meatal depth than do larger custom hearing instruments. Video Otoscopy can be used to locate the cotton block at or beyond the second meatal bend with a high degree of accuracy. Cotton is preferred over foam / sponge as a material for the block. Figure 1 (inline image below,12k) shows the obscured image resulting from the use of a bare oto-endoscopic rod as a cotton block probe. Canal landmarks are not available as an indicator of depth during placement.
Figure 2 A-D (inline images below, 18k) illustrates the method for modifying a disposable wax curette to serve as an ear block placement extension to the oto-endoscopic rod. Note (2C) that a narrow jet of hot air (i.e. Wahl spot heater model 5800 or later) is applied during the bending process using a jeweler's pliers.
For both ear block placement and cerumen curettage, safe, controlled management of the VO head is essential. In Figure 3 (inline image below, 19k) (A) shows a constant contact of the middle finger with the pre-auricular area on or near the zygomatic arch. This offers a significant barrier against the adverse effects of a sudden head movement. The otoscope is nestled in the crotch formed by the intersection of the thumb and index finger. Note (C) that both fiber optical source light cable and camera cable ride over the dorsal surface of the hand. The otoscope is advanced or retracted with the thumb and index finger (B). Vertical mobility of the VO probe is controlled by wrist movement.
Figure 4 (inline image below, 17k) presents a representative image of deep canal (#2) cotton block placement using the procedure described above.