9Wullstein's Tympanoplasty Classification: Types I to V

FOne scheme, five answers

Before there was a vocabulary for ossicular reconstruction, there was a problem: the same operation — closing a hole in a hearing mechanism — presented a different anatomy in every ear. In 1956 Horst Wullstein gave surgeons their first shared language for that problem, dividing reconstructive middle-ear surgery into five types according to how much of the sound-conducting chain still survived to build upon [1956]. His near-contemporary Fritz Zöllner reached the same destination by a parallel route, and the two are usually credited together with founding the tympanoplastyconcept — the deliberate reconstruction of a sound-conducting mechanism rather than the mere eradication of disease [1955].

The organising idea is simple and still worth internalising. Read the chain from the eardrum mediallyand ask how far inward intact, mobile structure persists. The further the surgeon must reach to find something to graft against, the higher the Wullstein number — and, broadly, the poorer the prognosis. Type I repairs the drum alone over an intact chain; type II grafts onto an eroded ossicular remnant; type III grafts onto an intact stapes head; type IV grafts onto a bare but mobile footplate; and type V confronts a fixed footplate, classically by fenestration. The widget below lets you step through all five and see what survives in each.

Two structures do most of the work in deciding the type: the stapes superstructure and the mobility of the footplate. Whether the superstructure is present separates type III from type IV; whether the footplate is mobile or fixed separates type IV from type V. Keep those two questions in mind and the whole scheme becomes a short decision rather than a list to memorise.

FTypes I and II: drum and remnant

Type I is the most familiar operation in otology under another name: myringoplasty. The ossicular chain is intact and mobile, the only fault is in the tympanic membrane, and the entire procedure is to graft the perforation closed. Nothing is done to the ossicles because nothing needs to be — a working transformer simply has its input membrane restored. Hearing results are correspondingly the best of the five types, because no link in the conductive chain has been substituted.

Type IIbegins the reconstructive work proper. Here the malleus or the incus has been partly eroded — most often the long process of the incus, the chain’s most vulnerable segment — while the stapes remains intact and mobile. Wullstein’s original solution was to lay the graft onto whatever ossicular remnant survived, transposing the drum onto the malleus handle or a remaining incus fragment so that the chain, though shortened, still conducted. In modern terms this is the territory of incus interposition or a partial prosthesis, but the classifying idea is unchanged: a usable ossicular remnant exists, and the graft is built onto it.

Notice that types I and II share a crucial feature — the stapes is intact and mobile, so the cochlea is still driven through its natural piston. This is why their prognosis is favourable and why they sit at the foundation end of the scheme. The harder problems begin only when the superstructure is gone.

TType III: the columella effect

In a type III reconstruction the malleus and incus are both gone, but the stapes superstructure is intact and mobile. Wullstein’s manoeuvre was to drape the graft directly onto the head of the stapes, so that the drum and the stapes are coupled with no intervening ossicle. The stapes then behaves as a single supporting strut between the new drum and the footplate — a columella, borrowing the term from the single-bone sound conductor of the avian middle ear. The arrangement has historically been called a myringostapediopexy.

The columella effect is mechanically efficient because the stapes, with its footplate, is the structure that ultimately must move; coupling the drum straight to it preserves a short, well-aligned force path. The trade-off is loss of the ossicular lever and a shallower middle-ear space, so a small residual air–bone gap is expected even with a technically perfect result — a cavity reconstruction can approach, but never exceed, the native transformer gain [1998]. Type III remains one of the most commonly performed reconstructions in chronic ear surgery, now usually realised with a partial ossicular replacement prosthesis (PORP) resting on the stapes head rather than with the drum laid directly upon it.

TType IV: grafting the bare footplate

Type IVis where the elegance of Wullstein’s thinking is most visible. The stapes superstructure has been lost, leaving only the mobile footplatesitting in the oval window. Simply laying a graft across the whole cavity would be acoustically disastrous: with no chain to create asymmetry, sound would reach the oval and round windows almost equally and in phase, cancelling the pressure difference across the cochlear partition — an acoustic short circuit that leaves the cochlea undriven [1998].

Wullstein’s answer was to engineer asymmetry deliberately. The graft is brought down to contact the footplate directly, while a small air-containing pocket — the cavum minor — is preserved over the round window to shield it from sound. With one window driven and the other protected, a useful pressure difference is restored across the partition and hearing returns, albeit modestly. Temporal-bone work confirms the principle directly: obliterating that protective pocket (for instance filling it with fluid) reduces stapes velocity toward the noise floor, whereas an air-filled shield preserves it. In a representative clinical series of type IV ears with total ossicular loss, around 58%achieved an air–bone gap under 30 dB and about 26%reached a serviceable hearing level under 40 dB [1998].

Today the same anatomy is far more often reconstructed with a total ossicular replacement prosthesis (TORP)standing on the footplate, which restores a proper coupled drive rather than relying on a bare round-window shield. But the type IV principle — that the two cochlear windows must be driven asymmetrically — is one of the most important conceptual lessons in all of ear surgery, and it explains failures far beyond Wullstein’s own technique.

CType V: the fixed footplate and fenestration

Type V addresses the hardest residual anatomy of all: the chain is gone and the footplate is fixed, so the oval window cannot be made to move whatever is grafted onto it. If sound cannot enter the labyrinth through a stuck oval window, Wullstein reasoned, it must be given another door. His type V created that door by fenestration of the lateral semicircular canal— opening the bony labyrinth and covering the new window with the graft so that sound energy reaches the perilymph through the canal rather than the fixed footplate. It was an ingenious application of the fenestration operation that had been developed for otosclerosis.

Type V is now almost entirely of historical interest. Fenestration sacrifices some bone-conduction reserve and gives a permanent conductive deficit, and it has been comprehensively superseded by stapedotomy and stapedectomy, which restore the natural oval-window route by perforating or removing the fixed footplate and inserting a piston. A surgeon meeting a truly fixed footplate in a chronically diseased ear today will usually stage the procedure — control disease and reconstruct the drum first, then deal with the footplate later — rather than fenestrate. Still, type V completes Wullstein’s logic: every possible state of the conducting apparatus, from a fully intact chain to a fixed footplate, is assigned a reconstructive strategy.

CLegacy, limits and the modern crosswalk

Wullstein’s scheme has aged unevenly, and a clinician should hold both its strength and its weaknesses in view. Its enduring strength is conceptual: it was the first system to tie residual ossicular status to a reconstructive strategyand, implicitly, to a hearing prognosis, and a recent scoping review confirms that its type I–V terminology remains in active use more than six decades later [2018]. Almost every later classification descends from this idea — Austin reduced the question to the malleus handle and stapes superstructure [1971], Kartush extended that scheme and added a risk index [1994], and Bellucci added the inflammatory state of the middle ear as a separate axis [1973].

Its limits follow from being a product of its era. The scheme is technique-bound— types describe Wullstein’s own graft manoeuvres rather than the prosthetic reconstructions (PORP, TORP) used today — and it is purely anatomical, saying nothing about mucosal disease, drainage, prior surgery or eustachian function, all of which strongly shape the result. It also encodes an assumption that modern outcome data have partly overturned: the presence of the stapes superstructure is not always the dominant predictor of hearing gain it was once taken to be, with statistical staging systems finding other factors weigh more heavily [2001]. The crosswalk below translates each Wullstein type into what it really means anatomically and how the same ear would be reconstructed now.

The practical takeaway is to use Wullstein as a concept and Austin or a risk index as a working tool. When you read an old operative note describing a “type III tympanoplasty” you will know it means a columella onto the stapes head; when you write a modern note you will more usefully record the malleus and stapes status, the prosthesis used, and the state of the ear. Wullstein’s lasting gift was not the five operations but the habit of reading the chain medially and letting what survives dictate the repair — the foundation on which the rest of this chapter is built.