<unk>  is a persistent disease. Once the diagnosis of<unk>  is made in a patient who can tolerate a general anesthetic, the standard treatment is to surgically remove the growth. The challenge of<unk>  surgery is to permanently remove the<unk>  whilst retaining or reconstructing the normal functions of the structures housed within the temporal bone. The general objective of<unk>  surgery has two parts. It is both directed against the underlying pathology and directed towards maintaining the normal functions of the temporal bone. These aims are conflicting and this makes<unk>  surgery extremely challenging. Sometimes, the situation results in a clash of surgical aims. The need to fully remove a progressive disease like<unk>  is the surgeon's first priority. Preservation of hearing is secondary to this primary aim. If the disease can be removed easily so that there is no increased risk of residual disease, then the ossicles may be preserved. If the disease is difficult to remove, so that there is an increased risk of residual disease, then removal of involved ossicles in order to fully clear<unk>  has generally been regarded as necessary and reasonable. In other words, the aims of<unk>  treatment form a hierarchy. The paramount objective is the complete removal of<unk> . The remaining objectives, such as hearing preservation, are subordinate to the need for complete removal of<unk> . This hierarchy of aims has led to the development of a wide range of strategies for the treatment of<unk> . Surgery The variation in technique in<unk>  surgery results from each surgeon's judgment whether to retain or remove certain structures housed within the temporal bone in order to facilitate the removal of<unk> . This typically involves some form of mastoidectomy which may or may not involve removing the posterior ear canal wall and the ossicles. Removal of the canal wall facilitates the complete clearance of<unk>  from the temporal bone in three ways: # It removes a large surface onto which<unk>  may be adherent; # It removes a barrier behind which the<unk>  may be hidden; # It removes an impediment to the introduction of instruments used for the removal of<unk> . Thus removal of the canal wall provides one of the most effective strategies for achieving the primary aim of<unk>  surgery, the complete removal of<unk> . However, there is a trade-off, since the functional impact of canal wall removal is also important. The removal of the ear canal wall results in: * a space, the "mastoid cavity", which is less likely than the original ear canal to resist infection; * exposure of the ossicles, which may allow the subsequent formation of a new<unk>  deep to the ossicles. To prevent this, these ossicles must be removed, which may diminish the patient's hearing. The formation of a mastoid cavity by removal of the canal wall is the simplest and most effective procedure for facilitating the removal of<unk> , but may bestow the most lasting infirmity due to loss of ear function upon the patient treated in this way. The following strategies are employed to mitigate the effects of canal wall removal: # Careful design and construction of the mastoid cavity. This is essential for the health and integrity of the protective sheet of migrating, keratising epithelium which lines the distorted ear canal. This requires the surgeon to saucerise the cavity. A high facial ridge and an inappropriately small cartilaginous meatus are obstructions to epithelial migration and are particularly high risk factors for failure of the self-cleaning mechanism of the external ear. # Partial obliteration of the mastoid cavity. This can be performed using a wide range of materials. Many of these resorb in time, which means that the long-term results of such surgery are poorer than the short-term results. # Reconstruction of the ear canal wall. Canal wall reconstruction has been performed using ear canal skin alone, fascia, cartilage, titanium as well as by replacing the original intact wall. If the reconstruction is poorly performed, it may result in a high rate of recurrent<unk> . # Preservation of the ear canal wall. If poorly performed, it may result in a high rate of both residual and recurrent<unk> . # Reconstruction of the chain of hearing bones using a passive middle ear implant. Clearly, preservation and restoration of ear function at the same time as total removal of<unk>  requires a high level of surgical expertise. The wide field view of the endoscope allows "looking around the corner" while utilizing the natural ear canal access to<unk> . Endoscopic surgery Traditionally, ear surgery has been performed using the surgical microscope. The direct line of view dictated by that approach necessitates using the mastoid as the access port to the middle ear. It has long been recognized that failure in<unk>  surgery occurs in some of the out of view spaces of the tympanic cavity like the sinus tymani and facial recess that are out of view using the traditional microscopic technique. More recently, the endoscope has been increasingly utilized in the surgical management of<unk>  in one of two ways: # Using the endoscope as an ancillary instrument to the microscope when trying to visualize areas that are hidden from the microscope such as the sinus tympani. This work was pioneered by Professor Thomassin. # Using the endoscope as the main surgical instrument through the ear canal, or what's called: Endoscopic Ear Surgery, pioneered by Professor Tarabichi. There are multiple advantages for the use of the endoscope in<unk>  surgery: # The endoscope wide angle of view and the ability to "see around the corner". # The endoscope allows minimally invasive access through the natural ear canal, rather than through the usual 5 cm incision behind the ear utilized in traditional microscopic surgery. # The 30 degrees endoscope allows access to the bony area of the Eustachian tube to address any obstructive pathologies.
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