CPT Code for Canal Wall Up Tympanomastoidectomy
The appropriate CPT code for this procedure is 69641 (tympanoplasty with mastoidectomy, including canalplasty, atticotomy, or epitympanic repair, with or without ossicular chain reconstruction; with intact or reconstructed wall).
Procedure Code Selection
The operative report describes a canal wall up tympanomastoidectomy with the following key features that determine coding:
Mastoidectomy performed: The surgeon drilled the mastoid cortex, identified the sigmoid sinus, tegmen, and lateral semicircular canal, and removed granulation tissue from the mastoid antrum 1, 2
Canal wall preserved: The posterior canal wall was maintained intact throughout the procedure, which is the defining characteristic of a "canal wall up" technique 1, 3
Middle ear entered: The procedure extended into the middle ear space where additional granulation and scar tissue was resected 4
Ossicular chain assessed: The incus short process and body were evaluated and found intact and mobile 3
Key Coding Distinctions
CPT 69641 is selected over other mastoidectomy codes because:
Not 69635 (transmastoid antrotomy): This procedure was more extensive than a simple antrotomy, as it included complete mastoidectomy with identification of all critical landmarks 2
Not 69645 (radical mastoidectomy/canal wall down): The posterior canal wall was explicitly preserved and re-approximated at closure 3, 4
Not 69646 (modified radical mastoidectomy): The tympanic membrane and ossicular chain were preserved, not removed 4
Documentation Supporting Code Selection
The operative note contains essential elements that justify CPT 69641:
- Elevation of musculoperiosteal flap to expose mastoid cortex 1
- Drilling to expose epitympanum and identify tegmen 2
- Skeletonization of sigmoid sinus 4
- Visualization of lateral semicircular canal 3
- Removal of diseased tissue from mastoid antrum and middle ear 2, 3
- Preservation of posterior canal wall with closure of Palva flap 4
The procedure complexity and extent clearly meet criteria for 69641 rather than simpler tympanoplasty codes (69631-69633), which do not include mastoidectomy components 5.