This document provides information on canal wall down (CWD) mastoidectomy surgery. It defines CWD mastoidectomy as the removal of the posterior and superior bony walls of the external ear canal and excision of all mastoid air cells, converting the mastoid cavity, middle ear, and ear canal into a single cavity exteriorized through the ear canal. It discusses indications for CWD mastoidectomy such as cholesteatoma, tumors, and anatomical factors like a low-lying tegmen. The document outlines the surgical technique and considerations like facial ridge lowering. It also addresses outcomes, complications, and the challenges of long-term management after CWD mastoidectomy.

1. CANAL WALL DOWN MASTOIDECTOMY
DR KANU LAL SAHA
ASSOCIATE PROFESSOR
OTOLOGY DIVISION
DEPT. OF OTOLARYNGOLOGY-HEAD AND NECK
SURGERY
BANGABANDHU SHEIKH MUJIB MEDICAL UNIVERSITY
SHAHBAG,DHAKA

2. CANAL WALL DOWN (CWD) CAN BE DEFINED AS :
 REMOVAL OF POSTERIOR AND SUPERIOR BONY
WALL OF EXTERNAL EAR CANAL(EAC)
 EXENTERATION OF ALL MASTOID AIR CELLS
 CONVERTING MASTOID CAVITY, MIDDLE EAR AND
EAC INTO A SINGLE CAVITY EXTERIORIZED
THROUGH EAC

3. CWD :SYNONYMOUS OR SUBCLASSIFICATION
 RADICAL MASTOIDECTOMY
 MODIFIED RADICAL MASTOIDECTOMY
 BONDY MASTOIDECTOMY
 MODIFIED BONDY MASTOIDECTOMY(SANNA MODIFICATION)
 ATTICOTOMY
 ATTICOANTROTOMY
OPEN CAVITY MASTOIDECTOMY

4. CWD MASTOIDECTOMY- INDICATIONS
CHOLESTEATOMA
 CONTRACTED MASTOID
 VERY LOW LYING TEGMEN AND ANTERIORLY PLACED SIGMOID SINUS
 ERODED BONY EAC
 RECURRENCE AFTER CWU MASTOIDECTOMY
 CLEFT PALATE AND DOWN’S SYNDROME
 ONLY HEARING EAR
 BILATERAL CHOLESTEATOMA
 LARGE LABYRINTHINE FISTULA
 SEVERE SENSORINEURAL HEARING LOSS
 SOME BENIGN TUMOURS INVOLVING THE MIDDLE EAR
 SOME MALIGNANCY IN THE EAC

5. CWD MASTOIDECTOMY INDICATION DISEASE FACTOR
Epitympanic
Cholesteatoma
Mesotympanic
Cholesteatoma
Postsurgical
Cholesteatoma
EAC
Malignancy
Paraganglioma
Facial Nerve
Haemangioma

6. CWD MASTOIDECTOMY IN CHOLESTEATOMA INDICATION ANATOMICAL FACTORS
Low lying Tegmen
Anteriorly placed
sigmoid sinus
Low lying Tegmen
Sclerosed mastoid

7. BILATERAL CHOLESTEATOMA

8. DESTRUCTED POST MEATAL WALL

9. RECURRENT CHOLESTEATOMA AFTER CWU

10. LABYRINTHINE FISTULA

11. CWD IN CHOLESTEATOMA INDICATION PATIENT FACTORS
INVESTIGATION FACILITIES
UNRELIABLE FOLLOW UP
UNWILLING TO UNDERGO A SECOND STAGE PROCEDURE
HIGH RISK FOR GENERAL ANESTHESIA
LACK OF RELIABLE IMAGING FACILITIES

12. CWD IN OTHER CONDITIONS: NOW REPLACED BY STP
PARAGANGLIOMA
FACIAL NERVE TUMOR
EAC MALIGNANCY

13. TYMPANIC PARAGANGLIOMA

14. FACIAL NERVE HAEMANGIOMA

15. TEMPORAL BONE MALIGNANCY

16. MODIFIED BONDY MASTOIDECTOMY
THE MODIFIED BONDY MASTOIDECTOMY
 A CWD MASTOIDECTOMY PROCEDURE
 REMOVAL OF POSTERIOR CANAL WALL
 INVOLVES EXTERIORIZING THE LATERAL EPITYMPANIC SPACE AND MASTOID CAVITY
 REMOVAL OF CHOLESTEATOMA
 PRESERVATION OF THE OSSICULAR CHAIN
 PLACING A FASCIA GRAFT ONTO THE MEDIAL ASPECT OF THE OSSICULAR CHAIN

17. BASIC SURGICAL STEPS
APPROACH:
RETROAURICULAR
ENDAURAL
ROUTES:
TRANSCORTICAL OR OUTSIDE-IN :
DRILLING STARTS ON THE SURFACE OF THE CORTICAL BONE
CORTICAL MASTOIDECTOMY-ANTROTOMY-REMOVAL OF BONY
EAR CANAL.
TRANSMEATAL OR INSIDE-OUT :
DRILLING STARTS IN THE EAR CANAL
ATTICOTOMY-ATTICOANTROSTOMY-MASTOIDECTOMY

18. RULES OF INITIAL DRILLING
• BONE COVERING THE MIDDLE FOSSA DURA
AND SIGMOID SINUS IS THINNED USING LARGE
BURRS.
• BURRS ARE MOVED PARALLEL TO THE
STRUCTURES.
• CAVITY MUST ALWAYS BE WELL SAUCERIZED AND
GRADUALLY DEEPENED.
• BONY OVERHANGS SHOULD BE REMOVED FROM
THE EDGES.

19. LOWERING FACIAL RIDGE
• THE FACIAL RIDGE IS LOWERED EVENLY USING A LARGE
CUTTING BURR WITH CONTINUOUS SUCTION IRRIGATION.
• DRILLING PARALLEL TO THE COURSE OF THE FACIAL NERVE.
• DIAMOND BURRS - FINAL DRILLING TO THIN THE BONY
COVERAGE OF THE NERVE.
• THE NERVE IS SKELETONIZED BUT NEVER EXPOSED
• INFERIOR CANAL WALL SHOULD BE CONTOURED
SMOOTHLY IN ITS JUNCTION WITH THE CAVITY.

20. REMOVAL OF ANTERIOR BUTTRESS AND CANALPLASTY
If prominent protrusion of anterior and inferior wall,
canalplasty should be done.
Meatal skin is cut laterally,detached from the bone
towards annulus and protected with a sheet.
Removal of anterior buttress produces a continuous
plane between middle fossa plate and anterior canal.

21. MASTOID CAVITY SAUCERIZATION
BY BEVELING THE EDGES OF THE CAVITY (BLUE),
THE LATERAL SOFT TISSUES (RED) ARE INVITED TO
COLLAPSE INWARD, WHICH ACTS TO REDUCE CAVITY
VOLUME.

22. CONTOURING THE TYMPANIC BONE JUNCTION WITH MASTOID CAVITY
DRILLING OF THE TYMPANIC BONE INFERIOR TO THE
TYMPANIC RING AND ANTERIOR TO THE FACIAL NERVE IS
NECESSARY TO ELIMINATE THE “KIDNEY SHAPE” OF THE
RESULTANT CAVITY AND TO PROVIDE A SMOOTH JUNCTION
BETWEEN THE NATIVE EXTERNAL AUDITORY CANAL AND
MASTOID CAVITY

23. PARTIAL OBLITERATION OF MASTOID CAVITY

24. RECONSTRUCTION
 BLEEDING SHOULD BE STOPPED COMPLETELY BEFORE RECONSTRUCTION OF MIDDLE EAR
 USUALLY THE TEMPORALIS FASCIA IS GRAFTED IN UNDERLAY TECHNIQUE
 ANTERIOR END OF GRAFT IS PLACED UNDER THE ANNULUS
 THE GRAFT MUST HAVE ABUNDANT POSTERIOR EXTENSION TO COVER THE WHOLE MIDDLE EAR AND OBLITERATED
CELLS
 IF NECESSARY, ANOTHER PIECE OF GRAFT MAY BE PLACED TO COVER EXPOSED BONE IN MASTOID CAVITY
 EPITHELIALIZATION IS FACILITATED IF THE EXPOSED BONE IS COVERED WITH THE FASCIA
 OSSICULOPLASTY MAY BE DONE IN FIRST-STAGE OR SECOND-STAGE

25. TYPE 2 TYMPANOPLASTY

26. TYPE 3 TYMPANOPLASTY
TYPE 3 USING AUTO MALLEUS HEAD TYPE 3 USING TORP

27. TYPE 3 TYMPANOPLASTY
TYPE-3 USING CARTILAGE TYPE 3 USING MALLEUS SHOE

28. MEATOPLASTY
 USING NASAL SPECULUM A CONCHAL INCISION IS MADE TOWARD THE ANTIHELIX, PARALLEL TO
CRUS OF THE HELIX
 CONCHAL CARTILAGE IS DISSECTED FROM SKIN AND UNDERLYING CONNECTIVE TISSUE
 A TRIANGULAR PIECE OF CARTILAGE IS REMOVED
 THE AMOUNT OF CARTILAGE TO BE REMOVED DEPENDS ON THE SIZE AND CONTOUR OF THE CAVITY
 IMPORTANT TO PRESERVE THE CARTILAGE IN THE CRUS OF THE HELIX TO PREVENT COSMETIC
DEFORMITY

29. SERIAL FOLLOW-UP AFTER CWD MASTOIDECTOMY

30. PROPERLY PERFORMED CANAL WALL DOWN MASTOIDECTOMY
A. SAUCERIZED EDGES
B. MASTOID TIP AMPUTATED FROM DIGASTRIC MUSCLE
C. CELLS DRILLED AWAY UP TO SMOOTH DURAL PLATE
D. FACIAL RIDGE LOWERED
E. TYMPANIC BONE SMOOTHLY FRACTURED WITH
JUNCTION OF MASTOID
F. INTACT TYMPANIC MEMBRANE
G. MIDDLE EAR SEALED FROM EPI
F
E

31. UNFAVOURABLE MASTOID CAVITY
A. THE STEEP NON-SAUCERIZED EDGES
B. THE POTHOLES FROM RESIDUAL AIR CELLS
C. THE INTACT OPEN MASTOID TIP WITH DEBRIS
D. THE HIGH FACIAL RIDGE
E. THE UNCONTOURED TYMPANIC BONE FORMING A
KIDNEY-SHAPED CAVITY
F. TYMPANIC MEMBRANE PERFORATION
G. UNSEALED COMMUNICATION WITH EPITYMPANUM
A
B
C
D
E
F
G

32. CAUSES OF FAILURE IN CANAL WALL DOWN MASTOIDECTOMY
POOR EXECUTION OF SURGICAL TECHNIQUE
HIGH FACIAL RIDGE
BONY OVERHANGS
NARROW MEATUS
Anatomical irregularity Percentage
High Facial ridge 67%
Stenotic meatus 64%
Bony overhang 29%
Canal wall down mastoidectomy: causes of failure,
pitfalls and their management. Mario Sanna et al
Journal of laryngology and otology,1995,vol-105

33. FAILURE IN CANAL WALL DOWN MASTOIDECTOMY :OTHER CAUSES
 PROMINENT OR INACCESSIBLE MASTOID TIP
 RECURRENT RETRACTION OR CHOLESTEATOMA
 REMUCOSALIZATION OF RESIDUAL MASTOID CELL
 VERY LARGE AND UNEVEN MASTOID CAVITY
 OPEN EUSTACHIAN TUBE OR PERFORATED

34. HIGH FACIAL RIDGE

35. Bony overhang
BONY OVERHANG

36. PROMINENT MASTOID TIP

37. CWD MASTOIDECTOMY: DISADVANTAGES
DIFFICULTY IN FITTING A HEARING AID
RESTRICTION TO WATER EXPOSURE/SWIMMING
DIZZINESS FOLLOWING TEMPERATURE OR PRESSURE CHANGES
REGULAR CLEANING OF KERATIN DEBRIS
ENLARGED MEATUS

38. CWD MASTOIDECTOMY: COMPLICATIONS
FACIAL NERVE INJURY
LABYRINTHINE INJURY
HEARING LOSS-CONDUCTIVE/SENSORINEURAL
CSF OTORRHOEA
TASTE DISTURBANCE

39. LONG TERM RESULTS OF CWD
MASTOIDECTOMY
Demographic and clinical data
n=259
Age 2-96(mean-35)
Male 39%
Female 61%
Type III tympanoplasty 175(67.4%)
Recurrent infection in cavity 17(6.5%)
Meatal stenosis 5(1.9%)
Residual cholesteatoma 5(1.9%)
Recurrent cholesteatoma 1(0.4%)
Sensorineural hearing loss 2(0.7%)
Facial paralysis 1(0.3%)
Persistent vertigo 4(1.5%)
Kos et al, Canal Wall-Down Mastoidectomy
Ann Otol Rhinal LaryngoI 113:2004

40. CWD MASTOIDECTOMY PERSONAL SERIES
Category Percentage
Modified radical mastoidectomy 124 (92.53%)
Modified bondy mastoidectomy 10(7.46%)
Category Percentage
Primary procedure 113(84.33%)
Revision surgery 21(15.67%)

41. CHOLESTEATOMA
Type of Cholesteatoma Percentage
Epitympanic cholesteatoma 53(40.45%)
Sinus cholesteatoma 42(32.06%)
Pars Tensa cholesteatoma 15(11.45%)
Unclassified 21(16.03%)

42. Demographic data
n=134
Age 5-15
>15
33
101
Male 100
Female 34
Right ear 60
Left Ear 74

43. STATUS OF
FACIAL
NERVE
CANAL
Facial nerve canal intact 82(61.19%)
Facial nerve canal dehiscent
Tympanic segment
Mastoid segment
Labyrinthine segment
52(38.80%)
41(78.85%)
6(11.53%)
5(9.61%)

44. INDICATIONS OF CWD MASTOIDECTOMY
Cholesteatoma 131(97.76%)
Tympanic
Paraganglioma
2(1.49%)
Facial nerve
haemangioma
1(0.74%)

45. OSSICULAR STATUS AND MIDDLE EAR RECONSTRUCTION
Type 1 Tympanoplasty 10(7.46%)
Type 2 Tympanoplasty 51(38.47%)
Type 3 Tympanoplasty 73(54.47%)
Stapes suprastructure present 51(38.05%)
Stapes suprastructure absent 73(54.47%)
Intact ossicular chain 10(7.46%)

46. FOLLOW-UP CWD CASE - PRIMARY SURGERY
Pre-op

47. FOLLOW- UP CWD CASE – AFTER REVISION
Post-op

48. FOLLOW-UP CWD -UNEVEN MASTOID
CAVITY

49. FOLLOW-UP CWD –UNSTABLE CAVITY

50. RECURRENCE AFTER CWD

51. HEALTHY MASTOID CAVITY WITH PERFORATION IN ANT
QUADRANT

52. POST –OP CASE OF MODIFIED BONDY MASTOIDECTOMY

53. CWD MASTOIDECTOMY CHALLENGES
PROPER EXECUTION OF SURGICAL TECHNIQUE
KEEP THE PATIENT IN REGULAR FOLLOW UP
OSSICULOPLASTY AND OPTIMUM HEARING IMPROVEMENT IN ONLY MOBILE
FOOTPLATE

54. CONCLUSION
 IT IS NOT WHICH TECHNIQUE ONE USES BUT HOW WELL ONE USES THE TECHNIQUE –THAT IS, THE INDIVIDUAL
SURGEON’S JUDGEMENT AND ABILITY -SHEEHY
 CWD IS RATHER MORE CRITICIZED OR DEFAMED FOR FAILURE THAN IT IS PERFECTLY PERFORMED
 A PERFECTLY PERFORMED CWD MASTOIDECTOMY RESULTS IN A TROUBLE-FREE, DRY EAR
 IN DEVELOPING COUNTRY LIKE US WHERE REGULAR FOLLOW-UP AND TECHNICAL SUPPORTS ARE LIMITED
CWD IS THE SINGLE STAGE SAFE PROCEDURE

55. THANK YOU
Otology Dr Kanu BSMMU Bangladesh
drklsaha@gmail.com
www.drkanuotology.com