Wullstein Classification of Tympanoplasty — Types I to V

Horst Ludwig Wullstein introduced his classification of tympanoplasty in 1952, publishing the definitive English account in 1956. The classification describes five operative types based on the state of the ossicular chain — specifically, which structures remain intact — and defines the surgical target for each. It is one of the most cited classification systems in otology and appears regularly in both MBBS and postgraduate examinations.

The logic of the classification is anatomical: the goal of tympanoplasty in every type is the same — to establish a closed, air-containing middle ear space with the tympanic membrane (or graft) positioned to transmit sound to the cochlea as efficiently as possible given what structures remain. The five types describe five different anatomical situations and the corresponding reconstruction strategies.

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The Principle Behind All Types

Sound transmission from the environment to the cochlea depends on a pressure differential across the footplate of the stapes. In a normal ear, this pressure differential is generated by the ossicular chain transmitting the tympanic membrane’s vibration to the oval window, while the round window membrane is shielded from direct sound pressure by the intact middle ear cavity. The round window is protected from sound — it receives pressure only via the ossicular chain route, through the cochlear fluid, arriving 180° out of phase with the oval window drive. This phase relationship is essential for efficient cochlear driving.

In any middle ear reconstruction, two functional prerequisites must be met: the new tympanic membrane (or graft) must vibrate in response to sound, and the round window must remain protected so that the pressure differential across the footplate is preserved. Every Wullstein type achieves these requirements with a different set of remaining structures.

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Type I — Myringoplasty

Intact ossicular chain. The tympanic membrane is perforated or absent, but the malleus, incus, and stapes are all present and mobile.

Reconstruction: The tympanic membrane defect is repaired with a graft — most commonly temporalis fascia or tragal perichondrium — applied medial to the existing membrane remnant (underlay technique) or lateral (overlay technique). No ossicular work is required.

Expected outcome: With a successful graft take, hearing can be restored to near-normal conductive levels because the transformer mechanism is intact.

Exam note: Wullstein’s original Type I is what most surgeons today call a myringoplasty — drum repair only. Some sources use “tympanoplasty Type I” and “myringoplasty” interchangeably; others reserve “tympanoplasty” for procedures involving ossicular work. In examinations, both usages are encountered.

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Type II — Graft to Malleus

Malleus handle present; incus absent or eroded. The most common scenario: the long process of the incus has been resorbed by chronic infection, breaking the ossicular chain, while the malleus handle and the stapes (or at least the footplate) remain.

Reconstruction: The tympanic membrane graft is placed medial to the malleus handle, resting on it. The graft contacts the malleus handle directly. If the stapes suprastructure (head and crura) is present, a prosthesis (partial ossicular replacement prosthesis, PORP) may bridge the gap between the graft or malleus handle remnant and the stapes head.

Expected outcome: Moderate improvement in hearing; residual conductive gap is common because the normal incus lever arm is absent, reducing the mechanical efficiency of the system.

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Type III — Myringostapediopexy (Graft to Stapes Head)

Malleus and incus absent; stapes suprastructure (head and crura) present and mobile. The entire ossicular chain above the stapes has been destroyed — a common finding in cholesteatoma surgery — but the stapes retains its suprastructure.

Reconstruction: The tympanic membrane graft is placed directly onto the stapes head, creating a columellar effect — a single-element transmission pathway from the drum to the cochlea, analogous to the single-bone arrangement seen in many non-mammalian vertebrates. The name refers to this: the graft contacts the stapes (myringostapediopexy = drum-stapes fixation).

Expected outcome: A conductive hearing loss remains (typically 20–30 dB) because the normal transformer mechanism is bypassed — the impedance matching achieved by the malleus-incus lever and the tympanic membrane area ratio is only partially replicated. However, hearing can be functionally useful.

Exam note: Type III is the most commonly examined and clinically performed of the non-Type I reconstructions. It is the type performed after canal wall down mastoidectomy clears cholesteatoma and the chain is absent to the level of the stapes head. The Austin-Kartush classification (see below) provides a more granular framework for ossicular reconstruction than Wullstein alone.

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Type IV — Graft to Stapes Footplate (Mobile Footplate)

Malleus, incus, and stapes suprastructure all absent; stapes footplate mobile. The entire ossicular chain above the footplate has been destroyed.

Reconstruction: A small middle ear cavity is created between the tympanic membrane graft and the mobile footplate. Critically, the round window must be shielded in this cavity — the graft is positioned to create a small air-containing pocket (the “sound protection cavity”) in front of the round window, so that the round window does not receive the same direct pressure as the footplate.

The principle: if the footplate receives direct sound pressure but the round window is shielded from it, a pressure differential exists across the cochlea and hearing is partially restored. The hearing result depends entirely on the protection of the round window from direct sound — without it, both windows receive equal pressure, the differential is zero, and hearing fails.

Expected outcome: Significant residual conductive hearing loss (often 40–50 dB), but functional gain from the protected round window. This type is rarely performed today as primary reconstruction; a total ossicular replacement prosthesis (TORP) from the drum to the footplate is usually preferred when the footplate is mobile.

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Type V — Graft to New Fenestra (Fixed Footplate)

Stapes footplate fixed (as in advanced otosclerosis or tympanosclerosis involving the footplate), with the ossicular chain otherwise absent.

Reconstruction: A new fenestra (opening) is created in the horizontal semicircular canal, and the tympanic membrane graft is placed to transmit sound directly through this new window into the inner ear, bypassing the fixed oval window.

Relevance today: Type V is largely of historical interest. It was developed before stapedectomy was refined. The results were poor (risk of inner ear damage from fenestration of the semicircular canal) and it has been superseded by stapedectomy and stapedotomy for footplate fixation. It appears in examinations as part of the complete classification.

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The Austin-Kartush Classification

Wullstein’s five types are broad. In clinical practice, many surgeons use the Austin classification (1971, modified by Kartush) which categorises the ossicular chain into specific groups based on what structures remain, guiding prosthesis selection:

Austin Group	Structures Present	Surgery
A	Malleus, incus, stapes present and mobile	Type I (graft only)
B	Malleus present, incus absent, stapes present	PORP (malleus to stapes head)
C	Malleus absent, incus absent, stapes present	PORP (graft to stapes head)
D	Malleus absent, incus absent, footplate only	TORP (graft to footplate)

PORP = partial ossicular replacement prosthesis (bridges from remnant to stapes head) TORP = total ossicular replacement prosthesis (bridges from drum/graft to footplate)

This classification is also examined at PG level and is the framework used in operative planning for cholesteatoma surgery.

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Expected Hearing Outcomes by Type

The speech reception threshold (SRT) post-operatively gives a practical guide to functional outcomes:

Type	Residual Conductive Gap (approximate)
Type I	0–10 dB (near-normal)
Type II	10–25 dB
Type III	20–30 dB
Type IV	30–50 dB
Type V	Poor; largely historical

These are approximations — actual outcomes depend on graft take, Eustachian tube function, middle ear aeration, and the patient’s pre-operative sensorineural reserve. The maximum achievable hearing with any reconstruction is limited by the underlying cochlear function (the bone conduction threshold).

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Key Numbers

Parameter	Value
Wullstein’s original publication	1956 (English); 1952 (German)
Type I — structure present	Intact malleus, incus, stapes
Type III — structure present	Stapes suprastructure only
Type IV — structure present	Mobile footplate only
Type V — clinical relevance	Historical; replaced by stapedectomy
PORP	Partial ossicular replacement prosthesis (to stapes head)
TORP	Total ossicular replacement prosthesis (to footplate)

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Frequently Asked Questions

Why is the round window so important in Type IV? In Type IV, the only cochlear drive comes from the direct pressure on the footplate. For this to produce useful hearing, the round window must experience a different pressure than the footplate — this differential is what drives cochlear fluid movement. If the round window is directly exposed to the same sound pressure as the footplate, both ends of the scala see the same pressure simultaneously, the net cochlear drive is zero, and no hearing occurs. The “sound protection” cavity in Type IV exists solely to shield the round window.

What graft material is used in tympanoplasty? The most commonly used materials are temporalis fascia (taken from the deep fascia overlying the temporal muscle above the ear, via a post-auricular or endaural approach) and tragal perichondrium (harvested from the back surface of the tragal cartilage, via the same incision used for transcanal endoscopic surgery). Cartilage perichondrium is increasingly preferred because cartilage grafts are stiffer, resist retraction better, and are particularly useful in ears with poor Eustachian tube function where a fascial graft would re-perforate or retract. Cartilage does not affect hearing outcomes significantly when used as a composite cartilage-perichondrium graft.

Is the Wullstein classification still used clinically? Yes, but it is often supplemented or replaced by the Austin-Kartush classification in clinical surgical documentation and research, because Austin better specifies which ossicular structures remain. Wullstein’s terminology — particularly “Type I” for myringoplasty and “Type III” for myringostapediopexy — is still universally understood, and the classification remains the standard framework in examination questions.