Overview and Introduction

Otologic surgeons have traditionally been required to judge the relative advantages of improved surgical exposure and superior cholesteatoma control afforded by canal wall-down (CWD) surgery against the benefits of preserved natural anatomy, avoidance of an open cavity, and improved hearing associated with canal wall-up surgery (CWU), also known as intact–canal wall (ICW) surgery. At issue is the exposure of the critical anatomic regions for cholesteatoma removal: the epitympanum and associated supratubal recess and the mesotympanum. These are the two areas associated with most recurrent disease.1 Primary acquired cholesteatomas typically begin as retraction pockets in the pars flaccida (epitympanic cholesteatoma) or posterior pars tensa (mesotympanic cholesteatoma), so adequate exposure of these areas is paramount.

CWU surgery, especially in cases with poorly developed zygomatic root cells and a low tegmen, can provide very limited exposure of the epitympanum and posterior mesotympanum, leading to blind and piecemeal removal of the cholesteatoma, which contributes to the high recidivism rate. Because of these shortcomings, second-stage surgery is frequently recommended 9–12 months after the initial CWU tympanomastoidectomy.2,​3,​4 A review of the literature shows a wide variation in the reported recurrence rates with this technique.2,​3 As pointed out so aptly by Smyth,1 long-term results with CWU cholesteatoma can be very humbling, with recurrence rates of 15% to 50%, even after staging. Nyrop and Bonding’s 10-year follow-up of CWU cases in Copenhagen showed that 70% required a later CWD surgery.5

The CWD technique creates an open cavity after removal of the bony posterior canal wall, providing excellent exposure for cholesteatoma removal. The epitympanum, cog, and supratubal recess are widely exposed, facilitating complete removal of the cholesteatoma sac and lowering the recurrence rate to 5–10%.6,​7 The main disadvantages of this technique are related to the necessity for periodic cleaning of the mastoid cavity.6,​7 Subsequent bowl infections can occur, especially when the cavity becomes wet, causing significant lifestyle changes, particularly in the pediatric age group.7 In addition, the hearing results are frequently worse due to the shallow middle ear cleft.6,​7

36.2 Evolution of Hybrid Techniques

There has been a trend toward the development of surgical techniques that involve temporary removal of the canal wall, offering the exposure of CWD surgery for cholesteatoma extirpation, followed by reconstruction of the canal wall defect using autologous (bone, cartilage) or alloplastic (hydroxyapatite cement, titanium) graft materials to capture the advantage of the CWU situation.8,​9,​10

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Dec 14, 2016 | Posted by in OTOLARYNGOLOGY | Comments Off on Overview and Introduction

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