6The Endaural Approach: Incisions and Exposure

FA route between two others

Every middle-ear reconstruction reaches the same destination — the tympanic cavity and the ossicular chain — but the surgeon may travel there by three corridors. The transcanal route works directly down the external canal through a speculum; the postauricular route swings behind the pinna to deliver the widest field; and between them lies the endaural approach, an incision placed within the meatus and carried up into the notch in front of the ear. It widens the canal without ever leaving a scar the patient can see in a mirror, which is why it earned a reputation as the cosmetic middle path of otological access [2023].

The endaural approach is not a compromise so much as a tool for a particular problem: the ear whose canal anatomy denies a clean transcanal view but whose disease does not warrant opening the mastoid. Understanding when that situation arises — and how the incision restores the view — is the whole substance of this module. The diagram below lets you compare the three corridors side by side before we examine the endaural one in detail.

FWhere the incision lives

The endaural incision was popularised by Julius Lempert, who used it for his one-stage fenestration operation and championed it over the postauricular route favoured by many of his contemporaries; the approach itself had been described earlier by Kessel in the nineteenth century [2015, 2023]. Its anatomy is precise. A canal-wall limb runs within the meatus near the bony–cartilaginous junction; from the twelve-o’clock position this turns upward and outward into the incisura terminalis— the natural cartilage-free notch between the tragus and the root of the helix. Because the incisura contains no cartilage and is relatively avascular, the incision opens the meatus widely with little bleeding and leaves a scar concealed within the ear[2011].

That siting is the source of every advantage and limitation that follows. By respecting the incisura, the endaural incision avoids dividing tragal or conchal cartilage, spares the postauricular skin, and yet hinges the soft tissue of the meatal entrance open so that the canal can be enlarged. It is, in effect, a way of making the external canal temporarily wider and straighter so that microscope and instruments can reach structures that a fixed speculum could not [2016].

FThe anterior canal problem it solves

The single commonest reason to abandon a transcanal approach is the anterior canal wall. The external canal is not a straight tube: it curves, and an anterior or anteroinferior bony bulge frequently overhangs the anterior tympanic annulus. Through a speculum, that bulge throws the anterior membrane into shadow, so the anterior perforation margin and the anterior recess simply cannot be seen [2016]. The consequences are practical and serious: a graft tucked under an unseen anterior annulus is prone to anterior blunting and residual perforation, and an incus or prosthesis placed without a clear anterior working angle may be malpositioned.

The endaural approach answers this directly. Opening the meatus exposes the anterior canal wall so that it can be drilled down — a canalplasty— removing the overhang and bringing the entire annular circumference, including its anterior arc, into a single field of view. The same manoeuvre helps the narrow or tortuous canal, the anterior overhang, and the medialised malleus, all of which the source literature lists as classic transcanal limitations that should prompt conversion to an endaural or postauricular route [2003]. In modern practice the angled endoscope passed transcanally addresses some of these same blind spots without an external incision, and the choice between widening the corridor mechanically and looking around the corner optically is now part of the decision [2016].

TRaising the exposure: from incision to annulus

Operatively, the sequence is logical. After infiltration of the meatal skin and the incisura with local anaesthetic and vasoconstrictor, the canal-wall limb of the incision is made near the bony–cartilaginous junction and joined to the limb running up into the incisura. A self-retaining endaural retractor then holds the meatus open, converting the speculum’s fixed aperture into an adjustable one. The meatal skin is elevated, and where an anterior or anteroinferior bulge obstructs the view it is drilled flush so that the anterior annulus comes into line of sight[2011].

Only then is the familiar middle-ear work begun: a tympanomeatal flapis raised, the annulus lifted from its sulcus, the chorda tympani preserved, and the ossicular chain inspected and palpated. The key conceptual point for the trainee is that the endaural incision is a means of access, not a different operation: the graft and the prosthesis are placed exactly as they would be transcanally, but now under direct vision of the whole tympanic ring. Because the corridor is wider, the anterior edge of an underlay graft can be supported precisely against the anterior annulus, which is the very interface most prone to failure when it cannot be seen.

It is worth being clear about what the outcome data above do and do not say. When the endaural and postauricular approaches are compared for tympanoplasty, graft uptake and hearing gain are broadly equivalent, with only small differences in graft rejection and complication rates [2017, 2011]. The approaches are not chosen because one heals the ear better than the other; they are chosen because each delivers a different field of exposure for a different anatomical and disease problem. The endaural route earns its place by giving anterior access with a hidden scar, not by improving the final audiogram.

TChoosing the endaural route

The decision is best framed as a hierarchy of exposure matched to need. A wide, straight canalwith an intact membrane and a limited reconstruction — a second-stage incus interposition, say, or a posterior PORP — is the ideal transcanal (or transcanal endoscopic) case, and widening the corridor would only add morbidity [2016]. At the other extreme, extensive attic or mastoid disease, cholesteatoma requiring clearance, or the need to expose the facial recess all call for the wide field of a postauricular approach with cortical mastoidectomy[2016].

The endaural approach occupies the middle ground precisely defined by two simultaneous conditions:

• The transcanal view is inadequate— a narrow or tortuous canal, an anterior bulge obscuring the anterior annulus, or a medialised malleus; and
• The disease does not demand the mastoid— the ear is dry, the pathology limited to the tympanic cavity and ossicular chain, and no mastoidectomy is anticipated, though a limited atticotomy or canalplasty may be.

When both conditions hold, the endaural route gives the access the case needs while sparing the patient a postauricular scar and the morbidity of opening the mastoid unnecessarily. A patient who is particularly concerned about a visible scar but needs more than a speculum allows is the archetypal endaural candidate[2011, 2017].

CTrade-offs, grafts, and pitfalls

For the clinician planning a list, three practical considerations refine the choice. The first is graft logistics. A postauricular incision exposes the conchal bowl through the same wound, so conchal cartilage — favoured for its natural convexity and thickness — is harvested without a second site. Through an endaural incision, tragal cartilage lies conveniently adjacent and is readily taken, but reaching the conchal bowl requires a small extension or separate access. This is a genuine but minor trade-off, not a contraindication: the choice of graft material is governed by the reconstruction, and only the harvest route changes[2003, 2011].

The second is healing and morbidity. Both endaural and postauricular routes are more invasive than a transcanal approach and carry a modestly longer healing time; meatal stenosis and incisional discomfort are the endaural-specific concerns, and a careful soft-tissue closure or meatoplasty mitigates them[2011]. The third is conversion discipline: an approach chosen at the outset is not a contract. If a case begun transcanally proves anteriorly blind, converting to endaural mid-operation is straightforward and legitimate; equally, if unexpected mastoid disease appears, the endaural field can be extended or the operation converted posteriorly [2016].

The enduring lesson is that exposure should be titrated to the problem. The endaural approach is the answer to a specific and common question — how to see and reconstruct the anterior tympanic ring in an ear that the speculum cannot serve, without the scar and morbidity of opening the mastoid. Used for that purpose, it gives excellent and cosmetically discreet access; used reflexively, it simply adds an incision the case did not need. Matching corridor to pathology, and converting without hesitation when the field falls short, is the mark of sound surgical judgement[2023, 2017].