mastoidectomy

DEFINITION of mastoidectomy

Mastoidectomy is a surgical procedure in which the mastoid air cells — the honeycomb-like bony spaces within the mastoid process of the temporal bone, located just behind the ear — are drilled out and removed to eliminate disease, most commonly mastoiditis, cholesteatoma, or chronic suppurative otitis media. Unlike a simple incision or drainage procedure, mastoidectomy involves entering the temporal bone itself and varies in extent depending on the degree of disease: a simple (transmastoid antrotomy) removes only diseased cells while preserving the posterior canal wall and middle ear structures; a complete mastoidectomy exenterates all mastoid air cells; a modified radical mastoidectomy takes down the superior and posterior canal walls to create an open cavity while preserving the tympanic membrane and ossicles when possible; and a radical mastoidectomy removes the tympanic membrane, malleus, and incus entirely, creating a single open cavity. The procedure may be combined with tympanoplasty (tympanoplasty with mastoidectomy codes, 69641-69646) or with petrous apicectomy (69530) when disease extends to the petrous apex. Mastoidectomy is frequently confused with myringotomy or tympanotomy, but those procedures address the tympanic membrane only and do not involve drilling the mastoid bone.

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ETYMOLOGY of mastoidectomy

greek | latin

Component	Origin	Meaning
mast-	Greek mastos (mas-tos)	“breast” — refers to the breast-like shape of the mastoid process; directional/anatomic prefix
-oid	Greek -oeidēs (-oy-deez), from eidos (form, shape)	“resembling,” “shaped like,” “in the form of”
-ectomy	Greek ektomē (ek-toh-mee), from ek- (out) + temnein (to cut)	Noun-forming surgical suffix — “surgical removal,” “excision of”

The word entered English in the 1870s as mastoidectomy (noun), formed in medical Latin from the combining form mastoid- (from Greek mastos, “breast,” + -oeidēs, “resembling”) plus the surgical suffix -ectomy (from Greek ektomē, “a cutting out”). The mastoid process was named for its nipple- or breast-shaped projection. The root mastos (“breast”) connects Mastoidectomy to anatomic and surgical terms including mastoid, mastitis, and mastectomy. The suffix -ectomy is one of the most productive surgical suffixes in medical terminology, appearing in appendectomy, cholecystectomy, tonsillectomy, thyroidectomy, and splenectomy.

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🔀 ALIASES / ALTERNATE TERMS

• Mastoidotomy (incision into the mastoid — distinct from mastoidectomy; mastoidotomy = incision only, mastoidectomy = excision/removal of cells; do not use interchangeably in coding)
• Transmastoid antrotomy (lay surgical term for simple mastoidectomy; coded as 69501; antrum is the mastoid antrum, the air space connecting to the middle ear)
• Simple mastoidectomy (removal of diseased mastoid air cells only, posterior canal wall preserved; 69501)
• Complete mastoidectomy (exenteration of all mastoid air cells; 69502)
• Modified radical mastoidectomy (canal wall taken down, tympanic membrane and ossicles preserved or reconstructed when possible; 69505)
• Radical mastoidectomy (tympanic membrane, malleus, and incus removed; creates single open cavity; 69511)
• Petrous apicectomy (radical mastoidectomy extended to petrous apex; 69530)
• Canal-wall-up mastoidectomy (posterior and superior bony canal walls preserved; combined with tympanoplasty → 69641 or 69642 or 69643 or 69644)
• Canal-wall-down mastoidectomy (posterior and superior canal walls drilled away; combined with tympanoplasty → 69645 or 69646)
• Revision mastoidectomy (reoperation on previously operated mastoid cavity; see 69601-69605 series)

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🔗 RELATED TERMS

• Mastoiditis — infection and inflammation of the mastoid air cells; the most common indication for mastoidectomy; must be coded with site specificity (e.g., H70.001, H70.011)
• Cholesteatoma — abnormal, non-cancerous keratinizing squamous epithelial growth in the middle ear or mastoid; the second most common indication; coded at the most specific anatomic site (attic, tympanum, or mastoid)
• Tympanoplasty — surgical repair of the tympanic membrane; frequently performed simultaneously with mastoidectomy — when combined, use the 69641-69646 series rather than separate codes
• Otitis media — middle ear infection; chronic suppurative otitis media is a major driver of mastoidectomy need; code with H66.3X1 (right), H66.3X2 (left), H66.3X3 (bilateral) series
• Temporal bone — the skull bone housing the mastoid process, middle ear, inner ear, and facial nerve canal; surgical landmark for mastoidectomy
• Ossiculoplasty — reconstruction of the ossicular chain (malleus, incus, stapes); may be performed simultaneously with tympanoplasty-mastoidectomy; drives selection of even-numbered CPT codes (69642, 69644, 69646)
• Tympanic membrane — the eardrum; its preservation or removal is a key driver of CPT code selection in mastoidectomy
• Facial nerve — CN VII; runs through the temporal bone in close proximity to the mastoid — decompression or injury risk is a critical surgical and documentation consideration
• Petrous apicectomy — surgical drainage of the petrous apex; requires radical mastoidectomy as part of the procedure (69530); distinct from standard mastoidectomy in extent and indication
• Myringotomy — incision of the tympanic membrane; commonly confused with mastoidectomy but far less invasive; does not involve the mastoid bone

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CODING CORNER

🏥 ICD-10-CM CODES

Acute Mastoiditis (H70.0x — Laterality Required)

Code	Description
H70.001	Acute mastoiditis without complications, right ear
H70.002	Acute mastoiditis without complications, left ear
H70.003	Acute mastoiditis without complications, bilateral
H70.009	Acute mastoiditis without complications, unspecified ear
H70.011	Acute mastoiditis with subperiosteal abscess, right ear
H70.012	Acute mastoiditis with subperiosteal abscess, left ear
H70.013	Acute mastoiditis with subperiosteal abscess, bilateral
H70.019	Acute mastoiditis with subperiosteal abscess, unspecified ear
H70.091	Acute mastoiditis with other complications, right ear
H70.092	Acute mastoiditis with other complications, left ear
H70.093	Acute mastoiditis with other complications, bilateral
H70.099	Acute mastoiditis with other complications, unspecified ear

Chronic Mastoiditis (H70.1x — Laterality Required)

Code	Description
H70.10	Chronic mastoiditis, unspecified ear
H70.11	Chronic mastoiditis, right ear
H70.12	Chronic mastoiditis, left ear
H70.13	Chronic mastoiditis, bilateral

Petrositis (H70.2x — Gradenigo Syndrome)

Code	Description
H70.201	Unspecified petrositis, right ear
H70.202	Unspecified petrositis, left ear
H70.203	Unspecified petrositis, bilateral
H70.209	Unspecified petrositis, unspecified ear
H70.211	Acute petrositis, right ear
H70.212	Acute petrositis, left ear
H70.213	Acute petrositis, bilateral
H70.219	Acute petrositis, unspecified ear
H70.221	Chronic petrositis, right ear
H70.222	Chronic petrositis, left ear
H70.223	Chronic petrositis, bilateral
H70.229	Chronic petrositis, unspecified ear

Cholesteatoma of Middle Ear (H71.x — Laterality Required)

Code	Description
H71.00	Cholesteatoma of attic, unspecified ear
H71.01	Cholesteatoma of attic, right ear
H71.02	Cholesteatoma of attic, left ear
H71.03	Cholesteatoma of attic, bilateral
H71.10	Cholesteatoma of tympanum, unspecified ear
H71.11	Cholesteatoma of tympanum, right ear
H71.12	Cholesteatoma of tympanum, left ear
H71.13	Cholesteatoma of tympanum, bilateral
H71.20	Cholesteatoma of mastoid, unspecified ear
H71.21	Cholesteatoma of mastoid, right ear
H71.22	Cholesteatoma of mastoid, left ear
H71.23	Cholesteatoma of mastoid, bilateral
H71.30	Cholesteatoma of middle ear and mastoid, unspecified ear
H71.31	Cholesteatoma of middle ear and mastoid, right ear
H71.32	Cholesteatoma of middle ear and mastoid, left ear
H71.33	Cholesteatoma of middle ear and mastoid, bilateral
H71.90	Unspecified cholesteatoma, unspecified ear
H71.91	Unspecified cholesteatoma, right ear
H71.92	Unspecified cholesteatoma, left ear
H71.93	Unspecified cholesteatoma, bilateral

Postmastoidectomy Complications (H95.0x)

Code	Description
H95.001	Recurrent cholesteatoma of postmastoidectomy cavity, right ear
H95.002	Recurrent cholesteatoma of postmastoidectomy cavity, left ear
H95.003	Recurrent cholesteatoma of postmastoidectomy cavity, bilateral ears
H95.009	Recurrent cholesteatoma of postmastoidectomy cavity, unspecified ear
H95.111	Chronic inflammation of postmastoidectomy cavity, right ear
H95.112	Chronic inflammation of postmastoidectomy cavity, left ear
H95.113	Chronic inflammation of postmastoidectomy cavity, bilateral ears
H95.119	Chronic inflammation of postmastoidectomy cavity, unspecified ear

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🔧 COMMON CPT CODES (Mastoidectomy-Related Procedures)

CPT Code	Description
69501	Mastoidectomy; transmastoid antrotomy (simple mastoidectomy) — diseased cells only removed, posterior canal wall preserved
69502	Mastoidectomy; complete — all mastoid air cells exenterated
69505	Mastoidectomy; modified radical — canal wall taken down, tympanic membrane and ossicles preserved or reconstructed when possible
69511	Mastoidectomy; radical — tympanic membrane, malleus, and incus removed; creates single open cavity
69530	Petrous apicectomy including radical mastoidectomy — extended procedure to petrous apex
69601	Revision mastoidectomy; resulting in complete mastoidectomy
69602	Revision mastoidectomy; resulting in modified radical mastoidectomy
69603	Revision mastoidectomy; resulting in radical mastoidectomy
69604	Revision mastoidectomy; resulting in tympanoplasty
69605	Revision mastoidectomy; with apicectomy
69641	Tympanoplasty with mastoidectomy (canal wall up); without ossicular chain reconstruction
69642	Tympanoplasty with mastoidectomy (canal wall up); with ossicular chain reconstruction
69643	Tympanoplasty with mastoidectomy; with intact or reconstructed canal wall, without ossicular chain reconstruction
69644	Tympanoplasty with mastoidectomy; with intact or reconstructed canal wall, with ossicular chain reconstruction
69645	Tympanoplasty with mastoidectomy; radical or complete, without ossicular chain reconstruction (canal wall down)
69646	Tympanoplasty with mastoidectomy; radical or complete, with ossicular chain reconstruction (canal wall down)

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⚠️ Coding Note: ICD-10-CM codes for mastoiditis (H70.x) and cholesteatoma (H71.x) require laterality — unspecified ear codes exist but should be avoided whenever documentation specifies the operative side; query the surgeon if the note is silent on laterality. For sequencing on inpatient profee claims, the condition requiring the mastoidectomy (e.g., cholesteatoma, chronic mastoiditis) is the principal diagnosis; postoperative complication codes from H95.x are sequenced secondarily only when applicable. Undercoding alert: H71.3x (Cholesteatoma of middle ear and mastoid) is frequently missed when the operative report documents disease in both compartments — the documentation trigger phrase is “disease extending into mastoid” or “cholesteatoma involving both middle ear and mastoid.” When a tympanoplasty is performed at the same session as mastoidectomy, do not code the mastoidectomy CPT separately — use the combination 69641-69646 series, and select the even-numbered code (69642, 69644, or 69646) only when ossiculoplasty is also documented. For revision mastoidectomy (69601-69605), confirm the resulting procedure type, as payers including Medicare and BCBS will deny if the resulting procedure type does not match the operative report.

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DERIVATIONS of mastoidectomy

TABLE definition AS Definition
FROM #medterm
WHERE length(filter(roots, (word) => econtains([[Mastoidectomy]].roots, word))) > 0 AND file.name != [[Mastoidectomy]].file.name
SORT file.name ASC

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Query functionality

TABLE definition AS Definition
FROM #medterm
WHERE length(filter(definition, (word) => econtains([[Mastoidectomy]].definition, word))) > 0 AND file.name != [[Mastoidectomy]].file.name

Med roots dictionary Appendix A Prefixes Appendix B Combining Forms Appendix C Suffixes Appendix D Suffix forms