1Preoperative Evaluation and Patient Selection: Chapter Overview

FWhy the workup decides the operation

Ossiculoplasty is often taught as a technical maneuver — choose a prosthesis, set it on the stapes, close the drum. Yet the decision that most determines the result is made before the patient reaches the operating table. The preoperative evaluation answers three linked questions: should this ear be reconstructed at all, when (in one stage or two), and with what strategy. Get those right and a modest technique succeeds; get them wrong and the finest prosthesis is wasted on an ear that was never going to hear, or never needed surgery in the first place.

The workup is a short, ordered sequence: a focused history, otomicroscopy, pure-tone audiometry, selective high-resolution CT, and finally a risk stratification that folds the findings into a prognosis. Each step answers a specific question, and the later steps are interpreted in the light of the earlier ones. This module walks the whole pathway and shows how the pieces combine; the rest of the chapter then drills into each component. Step through the sequence below.

Two themes recur throughout. First, candidacy is a hearing decision, not merely an anatomical one: a chain can look abnormal and not need touching, or look intact and be the source of a disabling gap. Second, the goal of evaluation is not only to plan the operation but to support honest counselling— telling the patient what an ear like theirs typically achieves, and where the realistic ceiling lies.

FHistory and otomicroscopy

The history sets the context the audiogram and scan are read against. Key threads are the pattern of discharge, any previous surgery (and how many revisions), the patient’s own sense of handicap, and crucially the status of the other ear. Reconstructing the only-hearing ear, or operating in the face of a poor contralateral ear, raises the stakes of every decibel of sensorineural risk and shifts the threshold toward caution. Modifiable factors matter too: smoking independently worsens tympanoplasty and ossiculoplasty prognosis, which is why it was added to the Middle Ear Risk Index [2001].

Otomicroscopy is the first direct look at the surgical field. It documents the drum (perforation, retraction, lateralization, atelectasis), searches for cholesteatoma, and — where the chain is visible — palpates ossicular mobility. The examination can mislead in both directions: a chain that looks continuous may be fixed at the attic or the footplate, while a chain that looks discontinuous may be bridged by a functional band of fibrous tissue. This is why the examination is paired with audiometry rather than trusted alone, and why the chain is always reassessed directly at surgery.

TThe audiogram: the central document

Of all the investigations, the pure-tone audiogram is the one that most directly governs candidacy. Properly masked air and bone conduction do two things. They quantify the air–bone gap— the conductive component that ossiculoplasty can actually close — and they reveal the bone-conduction thresholds that fix the ceiling: an ear with poor cochlear reserve cannot hear well however perfectly the chain is rebuilt. Surgery is aimed at the gap, not the total loss.

The magnitude of that gap is itself a selection criterion. A small conductive loss — conventionally under roughly 15 dB— in an intact, mobile chain is generally a reason to counsel against ossiculoplasty: a gap that small is unlikely to improve reliably, and operating exposes a well-functioning chain to needless risk. At the other extreme, severe-to-profound sensorineural loss limits the audible benefit any reconstruction can deliver, and several series caution against routine ossiculoplasty in that setting because preoperative loss severity correlates with poorer hearing gain [2024]. The candidacy explorer below shows how these gating findings steer the decision.

Audiometry is rarely read in isolation. Tympanometryand acoustic-reflex testing corroborate the conductive picture — a flat (type B) trace points to effusion or perforation, while a stiff or hypermobile pattern hints at fixation or discontinuity. Speech audiometry checks that the word-recognition score is consistent with the pure-tone reserve, guarding against a retrocochlear surprise. And a careful look at the bone-conduction linematters in its own right: a notch at 2 kHz (the Carhart notch) can flag stapes fixation and a mechanical artefact that may partly reverse after surgery. None of this changes the central role of the air–bone gap, but together these tests keep the surgeon from reconstructing a chain whose problem was never conductive in the first place.

The audiogram also frames realistic targets. Across large series, success is conventionally defined as closing the postoperative air–bone gap to within 20 dB, achieved in roughly 60–65%of ears overall — with bone and titanium prostheses giving broadly similar results — and more often in favourable, dry, primary ears than in revised, draining cavities [2024]. Knowing that distribution is what lets the surgeon promise effort and an honest probability rather than a guaranteed decibel.

TImaging: a roadmap, not a verdict

High-resolution CT of the temporal bone, acquired in sub-millimetre slices and reformatted in multiple planes, is the workhorse image. It maps the things the microscope cannot see: the extent of disease in the attic and mastoid, the integrity and position of each ossicle, the facial canal (including dehiscence), the state of the round and oval windows, and impending or established complications. For revision ears and squamous disease especially, it functions as a surgical roadmap that shapes the approach before the first incision.

Two cautions keep CT in its place. First, its accuracy is good but imperfect: validation studies comparing preoperative CT with intraoperative findings show useful but incomplete agreement on ossicular status, with the attic and the malleus–incus complex among the harder regions to call [2024]. Second, CT shows anatomy, not hearing— it can neither measure the air–bone gap nor judge cochlear reserve, so it never determines candidacy on its own. The scan informs the operative plan; the audiogram and the examination decide whether to operate, and the chain is confirmed under the microscope at surgery.

It also helps to know whenCT earns its place. A simple, dry, primary central perforation with an intact, mobile chain on examination and a small gap often needs no scan at all — the operation is straightforward and the image would not change it. CT adds most where the stakes or the uncertainty are higher: suspected or confirmed cholesteatoma, a revision ear with distorted anatomy, an only-hearing ear, unexplained vertigo or a facial-nerve concern, or any sign of intracranial or labyrinthine complication. Used selectively in this way, the scan sharpens the plan without becoming a reflex that delays an otherwise clear decision.

CRisk stratification and prognosis

Once the findings are assembled, a validated risk indexconverts them into a prognosis. The earliest tools encoded clinical experience: Kartush’s Middle Ear Risk Index (MERI), built on the Austin–Kartush ossicular grade and disease variables [1994], and Black’s SPITE method, which grouped prognostic features into Surgical, Prosthetic, Infection, Tissue and Eustachian families for structured counselling [1992]. Dornhoffer and Gardner then built the OOPSindex by multivariate analysis, finding — against intuition — that mucosa, malleus and drainage predicted outcome while the stapes superstructure and cholesteatoma did not independently survive [2001].

The most recent and best-validated tool is the multi-institutional Ear Environment Risk (EER) score, derived from 1,679 ossiculoplasties and explicitly benchmarked against MERI and OOPS in the same cohort [2025]. Its great practical value is that it sorts ears into bands — favourable, low, intermediate and high — across which the mean postoperative gap climbs cleanly, from about 16 dB to roughly 32 dB. That stepwise gradient is precisely what risk-banded counselling needs.

Read these tools honestly. Even the EER correlates only modestlywith an individual outcome, and no index captures the intraoperative nuances — footplate mobility, adhesions, the quality of the malleus as a strut — that often decide a single case [2025, 2001]. The right use of a score is to structure counselling and standardize comparison, not to promise a decibel or to refuse an operation outright.

CSynthesis: who, when, and with what

The evaluation comes together as three decisions. Who is reconstructed.A patient with a meaningful air–bone gap (broadly 15 dB or more) that causes handicap, a dry or cleared ear, and useful cochlear reserve is a sound candidate; a trivial gap in an intact mobile chain, or an ear with little cochlear reserve, is a reason to counsel against surgery and consider amplification instead.

When. The state of the mucosa and disease control drives the timing. A wet ear, extensive cholesteatoma, or a high-risk band argues for a stagedapproach — clear and ventilate first, reconstruct once the environment is favourable — whereas a dry, low-risk primary ear can usually be reconstructed in a single stage. With what. The ossicular findings then guide the strategy: an intact stapes superstructure favours a partial reconstruction (PORP), an absent superstructure a total one (TORP), and material choice (titanium, hydroxyapatite, autograft) follows local practice, with bone and titanium giving broadly comparable hearing results [2024].

Above all, the preoperative evaluation is what turns ossiculoplasty from a gamble into a considered intervention. By the time the patient consents, the surgeon should be able to say, in plain terms, why this ear will be reconstructed, when, with what, and what an ear like theirs typically achieves. The chapters that follow take each step of this pathway in turn; this overview is the map that holds them together.