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Write about the post operative mastoid cavity problems. Describe various surgical measures for obtaining small, self cleaning cavity. Mastoid cavity obliteration in detail according to standard ent textbook

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Now I have all the material needed. Here is the comprehensive answer compiled from Cummings Otolaryngology, Scott-Brown's Otorhinolaryngology, Shambaugh's Surgery of the Ear, and KJ Lee's Essential Otolaryngology.

Post-Operative Mastoid Cavity Problems, Surgical Measures for a Small Self-Cleaning Cavity, and Mastoid Obliteration

1. The Post-Operative Mastoid Cavity: Overview

Canal wall-down (CWD) mastoidectomy - whether modified radical, radical, or the Bondy procedure - is highly effective at eradicating cholesteatoma, but it creates an open mastoid bowl that demands lifelong management. The self-cleaning mechanism of the external auditory canal (EAC) - epithelial migration outward from the tympanic membrane - is largely lost after CWD mastoidectomy, because the bowl is simply too large for this mechanism to work reliably.
Wormald and Nilssen evaluated 101 mastoid cavities at 6 months to 20 years postoperatively; 52% were actively discharging and 48% were dry. This reflects the enormous variability in outcomes depending on surgical technique and patient factors.
  • Scott-Brown's Otorhinolaryngology, Vol 2, p. 1051

2. Problems of the Post-Operative Mastoid Cavity

The following problems are recognized causes of a persistently draining or problematic cavity:

A. Surgical Technique-Related Causes

1. High Facial Ridge The facial ridge is the bony prominence overlying the vertical segment of the facial nerve (fallopian canal). If left too high, it creates an overhanging ledge that:
  • Obstructs visualization of the sinus tympani and hypotympanum
  • Prevents epithelial migration across the floor of the cavity
  • Creates a dependent recess that traps debris and moisture
The facial ridge must be lowered to the level of the visible fallopian canal. This is one of the most common causes of a persistently discharging cavity.
  • Shambaugh Surgery of the Ear, p. 808; Cummings Otolaryngology, p. 2745
2. Inadequate Meatoplasty The size of the external auditory meatus must be proportionate to the size of the mastoid cavity. A small meatus:
  • Prevents adequate ventilation and drying of the cavity
  • Traps debris and promotes infection
  • Makes aural toilet in the clinic difficult or impossible
A meatoplasty is almost always required after CWD mastoidectomy.
3. Dependent Tip Cell (Sump Effect) The mastoid tip extends inferiorly below the floor of the bony EAC. If the lateral mastoid tip cells (lateral to the digastric ridge) are not exenterated, a "sink trap" or sump is created. Secretions pool in this dependent space and discharge intermittently. The tip cells lateral to the digastric ridge must be removed so that the mastoid cavity floor is flush with the EAC floor.
  • Shambaugh Surgery of the Ear, p. 808; KJ Lee's Essential Otolaryngology, p. 1214
4. Exposed Eustachian Tube If the tympanic membrane is not adequately reconstructed, the Eustachian tube orifice communicates with the mastoid bowl. Mucus secreted by the middle ear and Eustachian tube enters the cavity and causes persistent mucoid or mucopurulent discharge.
5. Overhanging Ridges and Inadequate Saucerization Incomplete removal of the superior canal wall (tegmen angle, or "suprameatal spine"), the posterior buttress, or other overhanging bony ledges creates recesses in which squamous debris and wax accumulate, preventing self-cleaning.
  • Shambaugh Surgery of the Ear, p. 808
6. Incomplete Removal of Air Cells Residual air cells - particularly peritubal, perilabyrinthine, retrofacial, zygomatic, and hypotympanic cell tracts - lined with respiratory-type mucosa continue to secrete and drain into the bowl, perpetuating discharge.

B. Disease-Related Causes

CauseEffect
Residual/recurrent cholesteatomaKeratin accumulation, bone erosion, foul otorrhoea
Residual granulationsChronic suppuration
Tympanic membrane perforationContinued middle ear-cavity communication
Osteitis of exposed boneBony sequestrum, chronic bone infection

C. Patient-Related Factors

  • Large, well-pneumatized mastoid producing a large bowl
  • Water contamination (swimming, bathing)
  • Hearing aid mold occlusion of the meatus - traps moisture, reduces ventilation, and often leads to infection

3. Aims of Surgery for Active Squamous COM (Cholesteatoma)

The three stated aims are:
  1. Eradication of disease
  2. An epithelialized, self-cleaning ear
  3. Hearing maintenance or improvement
"The idea that the aim of surgery is simply to remove disease in order to create a safe ear is obsolete."
  • Scott-Brown's Otorhinolaryngology, Vol 2, p. 1051

4. Surgical Measures for Obtaining a Small, Self-Cleaning Cavity

A dry, self-cleaning mastoid cavity can be maintained in 95% of cases if strict attention to operative technique is paid.
  • Shambaugh Surgery of the Ear, p. 800
The following are the key surgical measures:

A. Adequate Saucerization of the Cavity

  • All bony overhangs, ledges, and irregular walls must be smoothed with a drill
  • The cavity must be rounded and smoothly contoured with no overhanging ridges
  • Cortical edges of the mastoid and tip are aggressively saucerized
  • The tegmen angle (superior buttress) and posterior buttress are completely removed so there is a smooth continuum between the mastoid tegmen and the tegmen tympani
  • This smooth geometry promotes centrifugal epithelial migration from the drum remnant outward
  • Scott-Brown's Otorhinolaryngology, Vol 2, p. 1051

B. Lowering the Facial Ridge

  • The posterior canal wall is lowered until the facial nerve is visible at the level of the fallopian canal
  • This step enlarges the cavity, removes the dependent sump behind the ridge, and improves visualization
  • The chorda tympani nerve is sacrificed as part of this maneuver
  • Shambaugh Surgery of the Ear, p. 802; Cummings Otolaryngology, p. 2744

C. Exenteration of All Air Cell Tracts

All mastoid air cells are exenterated, including:
  • Peritubal cells
  • Perilabyrinthine cells
  • Retrofacial cells
  • Zygomatic cells
  • Hypotympanic cells
  • Mastoid tip cells lateral to the digastric ridge (to eliminate the sump)
These cells should be covered with fascia grafts to reduce granulations and speed epithelialization.
  • Shambaugh Surgery of the Ear, p. 803

D. Small Cavity Mastoidectomy (Anterior-to-Posterior Approach)

Rather than the traditional posterior-to-anterior approach which opens a large cavity, Sade's atticoantrostomy (anterior-to-posterior approach) has become popular:
  • The cholesteatoma is identified anteriorly in the epitympanum and followed posteriorly
  • This results in a much smaller cavity (mean volume 1.4 cm³ vs. 2.4 cm³ with modified radical mastoidectomy; Smyth and Brooker)
  • No difference in discharge rates was found between the two techniques
  • When disease is limited, surgery can be restricted to atticotomy alone, with closure of the attic wall defect using tragal or conchal cartilage with perichondrium
  • Scott-Brown's Otorhinolaryngology, Vol 2, p. 1051

E. Adequate Meatoplasty

A large meatoplasty is essential:
  • The meatus size must be proportionate to the cavity size
  • Conchal cartilage is excised from behind using a posterior incision through the conchal bowl
  • The Körner (meatal) flap is rotated and secured with sutures to the musculoperiosteum to maintain meatal shape
  • The conchal cartilage removed during meatoplasty can and should be used to partially fill (partially obliterate) the mastoid cavity, reducing its volume
  • Shambaugh Surgery of the Ear, p. 803 (Fig. 31-1i)

F. Tympanic Membrane Reconstruction (Tympanoplasty)

  • The tympanic membrane should be repaired to close all communication between the mastoid cavity and the mesotympanum/Eustachian tube orifice
  • The fascia graft is placed medial to the anterior annulus, extending over the stapes to the facial ridge into the mastoid bowl
  • As much exposed mastoid bone as possible should be covered with fascia grafts to reduce granulations and speed epithelialization
  • Shambaugh Surgery of the Ear, p. 802; Scott-Brown's, Vol 2, p. 1051

G. Partial Obliteration with Conchal Cartilage

The conchal cartilage harvested during meatoplasty is used to fill recesses and reduce cavity volume. This is the simplest and most immediately available form of partial obliteration. Partial obliteration reduces the surface area requiring epithelialization, decreases mucus-secreting surfaces, and improves the cavity's self-cleaning potential.

5. Mastoid Cavity Obliteration - In Detail

Historical Background

Modern obliteration techniques were originally advanced by Palva in the 1970s as a modification of Popper's flap - a postauricular musculoperiosteal flap rotated inward to obliterate the mastoid bowl. Later adaptations incorporated bone chips and bone pâté in combination with the flap. Since then, both autologous and alloplastic materials have been employed.
  • Cummings Otolaryngology, p. 2747

Indications

Primary Obliteration (at the time of CWD mastoidectomy):
  • Large pneumatized mastoid (which would otherwise create a very large cavity)
  • Patient is unlikely to maintain regular follow-up for aural toilet
  • Desire to reduce frequency of long-term bowl cleanings
  • Reduces cholesteatoma recidivism: in a systematic review of 13 studies and 1,534 patients, recurrent and residual cholesteatoma rates in obliterated cavities were 5.8% and 5.9%, respectively
  • Cummings Otolaryngology, p. 2747
Secondary ("Rehabilitation") Obliteration:
  • Chronically discharging mastoid bowl after prior CWD mastoidectomy that has failed conservative revision
  • Cavity that is epithelialized but debris-collecting and not self-cleaning
  • Vertiginous symptoms from thermal/caloric stimulation through a thin epithelial lining over the semicircular canals (wind, water, or suctioning)
  • Cavity causing problems with hearing aid fitting
  • Cummings Otolaryngology, p. 2747
In Bernardeschi's series of 46 patients obliterated secondarily with biosynthetic ceramic, 90% returned well-healed and re-epithelialized at 1 year, with slight improvement in air-conduction thresholds and no evidence of recurrent disease.

Materials Used for Mastoid Obliteration

Autologous Materials

1. Bone Pâté (Bone Dust)
  • Collected during drilling; a mixture of bone dust and blood
  • Osteoconductive: provides a scaffold for new bone formation
  • Requires coverage with a vascularized fascioperiosteal flap for incorporation
  • Reported dry ear rates of 80-95% in case series
  • Scott-Brown's Otorhinolaryngology, Vol 2, p. 1053; Cummings Otolaryngology, p. 2747
2. Bone Chips
  • Used in combination with bone pâté and musculoperiosteal flaps
  • Derived from cortical mastoid bone removed during the procedure
3. Cartilage (Conchal or Tragal)
  • The conchal cartilage excised during meatoplasty is the most readily available
  • Provides structural support and volume reduction
  • Used for partial obliteration of the bowl and for attic wall reconstruction
4. Musculoperiosteal (Fascioperiosteal) Flaps
  • The Palva flap: a posteriorly based postauricular musculoperiosteal flap is rotated inward to line and obliterate the mastoid bowl
  • Provides a vascularized tissue covering that promotes healing
  • Essential as a cover for all alloplastic and bone pâté obliteration - bare bone will not incorporate these materials without a vascular cover
  • Cummings Otolaryngology, p. 2747
5. Abdominal Fat Graft
  • Free fat graft harvested from the abdomen
  • Particularly used in obliteration after labyrinthectomy, translabyrinthine surgery, or CSF fistula repair
  • Also used in lateral temporal bone resection (in combination with a temporalis flap) to prevent osteoradionecrosis after radiotherapy
  • Shambaugh Surgery of the Ear, p. 842; Cummings Otolaryngology, p. 2747
6. Temporalis Muscle Flap
  • Pedicled flap rotated into the mastoid defect
  • Used particularly in large defects and after lateral temporal bone resection

Alloplastic / Biomaterial Options

1. Hydroxyapatite (HA) Granules
  • Bioactive calcium phosphate ceramic; osteoconductive
  • Must be covered by a vascularized fascioperiosteal flap
  • Good long-term integration; allows bone ingrowth
  • Also used as a canal wall prosthesis for posterior canal wall reconstruction
  • Scott-Brown's Otorhinolaryngology, Vol 2, p. 1053
2. Tricalcium Phosphate
  • Similar to hydroxyapatite; biocompatible
  • Gradually resorbed and replaced by bone
3. Biosynthetic Ceramic Materials
  • Modern bioactive ceramics; favored by some centers for secondary obliteration
  • In Bernardeschi's series: 90% success rate at 1 year
  • Cummings Otolaryngology, p. 2747
4. Titanium Canal Wall Prostheses
  • Used for reconstruction of the posterior canal wall after CWD mastoidectomy ("canal reconstruction mastoidectomy")
  • Aims to convert a CWD cavity back toward normal anatomy while retaining the surgical exposure gained

Surgical Technique of Mastoid Obliteration (Palva Flap + Bone Pâté - Classic Method)

  1. Postauricular approach through the prior or new postauricular incision
  2. Complete disease clearance - all cholesteatoma matrix and disease must be removed before obliteration. Leaving squamous epithelium in an obliterated cavity risks subsequent cholesteatoma pearl formation (though this has rarely been reported)
  3. Creation of the fascioperiosteal (Palva) flap - a posteriorly based flap of musculoperiosteum is elevated and preserved for rotation
  4. Exenteration and saucerization of all mastoid air cells; lowering of the facial ridge; meatoplasty
  5. Packing of the Eustachian tube - blocked with fascia or soft tissue to prevent mucus entry into the obliterated space
  6. Tympanic membrane reconstruction with temporalis fascia
  7. Obliteration of the cavity with the chosen material (bone pâté, HA granules, or fat)
  8. Rotation of the fascioperiosteal flap over the obliterating material to provide a vascular cover
  9. Large meatoplasty is created to ensure adequate drainage and visualization of the residual lateral cavity

Canal Reconstruction Mastoidectomy

An alternative to obliteration, this approach reconstructs the posterior canal wall after a CWD procedure using autologous bone grafts, cartilage, or alloplastic materials (including HA prostheses and titanium plates). Numerous protocols exist. The goal is to achieve the exposure and disease control of a CWD procedure while restoring normal canal anatomy, avoiding a mastoid bowl, and improving tolerance of water exposure and hearing aid fitting.
  • Cummings Otolaryngology, p. 2739

Outcomes of Mastoid Obliteration

MethodDry ear rate
Revision mastoidectomy (Jackson et al., 541 ears)89% clean, healed, dry
Obliteration with bone pâté or HA granules (multiple series)80-95%
Biosynthetic ceramic obliteration (Bernardeschi, 46 ears, 1 year)90%
Obliteration with vascularized tissue flapsComparable
Irving et al. reported better symptom scores in patients who had mastoid obliteration compared to those who had revision mastoidectomy alone.
  • Scott-Brown's Otorhinolaryngology, Vol 2, p. 1053

Special Consideration: Obliteration in Children

In children, CWD mastoidectomy and its cavity are particularly problematic:
  • "Mastoid misery" - children often find aural toilet unpleasant or intolerable, requiring general anesthesia for adequate debridement
  • The robust regrowth of mastoid cortical bone in children may compromise access through the meatoplasty over time
  • The associated meatoplasty may be problematic for cosmesis and hearing aid fitting
  • Obliteration of the mastoid and attic in CWD cavities reduces revision rates from 15-20% to 2-3% at 5 years with obliteration
  • It is hypothesized that obliteration of mastoid air cells after canal wall-up (CWU) surgery also prevents recurrence by eliminating gas absorption by mastoid mucosa, thereby facilitating maintenance of normal middle ear pressure
  • Cummings Otolaryngology (Pediatric chapter), p. 3658

6. Summary: Key Principles

  1. A persistently discharging cavity is usually the result of poor surgical technique - high facial ridge, inadequate meatoplasty, dependent tip cell, or unclosed tympanic membrane perforation
  2. The anterior-to-posterior (atticoantrostomy) approach creates smaller cavities
  3. A small, rounded, smooth, well-saucerized cavity with a low facial ridge, adequate meatoplasty, and closed tympanic membrane is the goal
  4. Obliteration - primary or secondary - achieves dry ears in 80-95% of cases and reduces cholesteatoma recidivism
  5. All obliteration materials (bone pâté, HA granules, fat) must be covered by a vascularized tissue flap to ensure incorporation
  6. Squamous epithelium must be completely removed before obliteration to prevent cholesteatoma formation within the obliterated cavity
Sources: Cummings Otolaryngology Head and Neck Surgery (6th ed.), pp. 2737-2748; Scott-Brown's Otorhinolaryngology Head & Neck Surgery Vol 2, pp. 1051-1053; Shambaugh Surgery of the Ear, pp. 798-810; KJ Lee's Essential Otolaryngology, p. 1214
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