Modified radical mastoidectomy

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modified radical mastoidectomy surgical steps diagram

A clinical transoperative photograph depicting a modified radical mastoidectomy in a patient with cholesteatoma of the external auditory canal (CEAC). The surgical field shows the mastoid cavity with evident erosion of the posterior wall of the external auditory canal (EAC). Key anatomical features include an intact tympanic membrane (TM) and a preserved thin bone band near the tympanic ring. The photograph demonstrates the moist, erythematous surface of the middle ear and mastoid structures, with visible white bony landmarks and reddish soft tissue typical of surgical exploration for cholesteatoma management. The image is framed by green surgical draping, and a digital timestamp is visible in the lower right corner. This visual serves to illustrate the intraoperative findings and surgical extent required to manage extensive mastoid involvement while preserving the ossicle chain and facial nerve integrity.

This clinical photograph shows multiple fragments of excised surgical tissue from a canal wall down modified radical mastoidectomy. The specimens, obtained in a piecemeal fashion, are displayed on a green sterile surgical drape. The tissue fragments vary in size and morphology, appearing as irregular, lobulated masses. They exhibit a heterogeneous color profile consisting of fleshy pink and vibrant red areas indicative of vascularization or granulation tissue, interspersed with paler, translucent, and firmer white regions suggestive of fibro-osseous components or calcified stroma. The specimen represents a benign fibro-osseous lesion involving the middle ear and mastoid cavity. This visual serves as an educational example of macroscopic specimen evaluation in otolaryngology and surgical pathology, highlighting the characteristic appearance of tissue removed during ear canal and mastoid surgery for benign neoplasms or chronic inflammatory processes.

This composite of three intraoperative endoscopic clinical photographs demonstrates key steps in a modified mastoidectomy and tympanoplasty for middle ear cholesteatoma. Panel (a) shows the exposed facial nerve canal (red arrow) and the stapedial base (red star) after the removal of cholesteatoma epithelium. Hemorrhagic granulation tissue is visible near the stapes, which is managed via bipolar cautery to prevent recurrence. Panel (b) depicts the surgical exposure of the sigmoid sinus vein wall (red triangle) following mastoid bone removal, showing a preserved basilar membrane after the removal of overlying disease. Panel (c) illustrates the reconstruction phase, showing the placement of an auricular cartilage graft to restore the ossicular chain connection to the vestibular window (Type III tympanoplasty). These images highlight the surgical management of cholesteatoma involving critical neurovascular structures like the facial nerve and sigmoid sinus, emphasizing preservation of anatomical integrity while ensuring complete lesion eradication in an otolaryngology context.

This medical schematic diagram illustrates the sequential surgical steps for creating a colonic urinary reservoir (neobladder) following a radical cystectomy. The procedure is depicted in five stages: Step A shows the initial antimesenteric incision in a folded segment of the sigmoid colon or rectum using electrocautery and stay sutures. Step B demonstrates the introduction of a laparoscopic Endo GIA stapler into the lumen for detubularization. Step C reveals the internal surface of the opened bowel segment with visible staple lines along the medial edges. Step D illustrates the implantation of bilateral ureteric stents into the reservoir, establishing an anti-reflux mechanism. Finally, Step E shows the completed pouch after the anterior seromuscular wall has been closed with continuous or interrupted sutures, transforming the tubular intestine into a wide, reservoir-like structure. This illustration serves as an educational tool for urological surgeons to understand the intraluminal stapling technique and detubularization logic required for urinary diversion.

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Modified Radical Mastoidectomy (MRM)

Definition and Concept

Modified radical mastoidectomy is a canal-wall-down (open cavity) procedure that exteriorizes the mastoid air cells, antrum, and epitympanum into one common surgical cavity while preserving the remnant tympanic membrane and any usable ossicles - differentiating it from the classic radical mastoidectomy, which sacrifices all middle ear structures and obliterates the eustachian tube.

The term is often (incorrectly) used interchangeably with "canal-wall-down mastoidectomy." Strictly speaking, MRM refers to the Bondy modification, in which disease limited to the epitympanum is exteriorized with only partial removal of the superior/posterior canal wall, leaving an intact middle ear with the cholesteatoma matrix maintained on the lateral ossicular heads as a cavity lining. The broader "complete mastoidectomy + tympanoplasty" represents the modern MRM concept.

Cummings Otolaryngology Head and Neck Surgery, block 31
Shambaugh Surgery of the Ear, block 5 & 7

Comparison of Mastoid Procedures

Feature	Canal Wall Up	Modified Radical (MRM)	Radical Mastoidectomy
Posterior canal wall	Preserved	Removed	Removed
Tympanic membrane	Reconstructed	Preserved/reconstructed remnant	Sacrificed
Ossicles	Preserved/reconstructed	Remnants preserved	Removed
Eustachian tube	Patent	Patent	Obliterated
Middle ear access	Limited	Full	All mucosa removed
Cavity cleaning	Not required	Required (lifelong)	Required
Hearing outcome	Best potential	Moderate	Poor

Indications

MRM is recommended when:

Cholesteatoma extending into the attic, antrum, or mastoid - especially when extensive canal wall destruction is already present
Occasional otologic surgeon confronted with cholesteatoma (less technically demanding than the staged canal-wall-up technique)
Patients unwilling or unable to undergo the two-stage canal-wall-up approach
Recurrent cholesteatoma after previous failed canal-wall-up surgery
The only functioning ear (safer single-stage approach)
Poor eustachian tube function (high risk of retraction pocket reformation)
Circumstances where second-look surgery is impractical

Conservative (office) management of cholesteatoma is contraindicated when:

CT shows enlarged, smooth-walled antrum (large cholesteatoma cavity)
Persistent otorrhea despite treatment
Evidence of complications (facial palsy, labyrinthine fistula, intracranial spread)
Shambaugh Surgery of the Ear, p. 541

Contraindications to Open Cavity (MRM)

Chronic otitis media without cholesteatoma
Acute coalescent mastoiditis
Persistent secretory or allergic otitis media
Tuberculous otitis media (treat medically first)
Relative: wide exposure of sigmoid sinus, dura, or facial nerve due to aggressive disease

Preoperative Assessment

Microscopic examination and cleaning; remove pus, mucus, cholesteatoma debris
Polyps removed carefully (may attach to facial nerve, labyrinthine fistula matrix, or stapes)
HRCT temporal bone (non-contrast): evaluates erosion of semicircular canals, cochlea, fallopian canal, dural plates, sigmoid sinus; scutum erosion on CT confirms attic cholesteatoma
MRI with gadolinium: adjunct for suspected intracranial extension, meningoencephalocele, sigmoid sinus thrombosis
Preoperative ear preparation: 1.5% acetic acid irrigations + antibiotic drops for weeks; oral fluoroquinolones (10-14 days) for extensive mucosal infection

Surgical Technique

Anesthesia and Preparation

General anesthesia
Povidone-iodine preparation of ear canal and auricle
Injection of 1% lidocaine with 1:100,000 epinephrine into postauricular region and canal (hemostasis)

Incision

Vascular strip incisions in the ear canal
Postauricular incision ~1 cm behind the postauricular crease
Plane developed between subcutaneous tissue and the temporalis muscle/mastoid periosteum
Harvest of temporalis fascia (for later tympanoplasty graft) - set aside to dry
Horizontal incision superior to the temporal line through temporalis; vertical incision creates musculoperiosteal flap

Middle Ear Entry

Canal wall flaps elevated and rotated anteriorly
Middle ear entered first: disease removed from mesotympanum using malleus handle and incus as landmarks
Cholesteatoma, polyps, and granulation tissue removed from all regions except posterosuperior quadrant initially
Atrophic tympanic membrane removed; middle ear prepared for grafting
Once landmarks identified, posterosuperior quadrant inspected - if disease extends to attic, dissection stops and Gelfoam + epinephrine is packed into middle ear

Bone Work (Mastoidectomy)

Simple mastoidectomy begun with large cutting bur; canal wall left up initially in all but the most contracted cavities
All mastoid air cells removed with exposure of:
- Middle and posterior fossa dural plates
- Sigmoid sinus
- Digastric ridge
- Bony canal wall
As labyrinth is approached: lateral capsule of cholesteatoma opened, matrix left on bony labyrinth - inspected under high magnification for blue line (labyrinthine fistula)
Facial nerve (vertical segment) identified; facial recess opened using digastric ridge and lateral semicircular canal as landmarks

Taking Down the Canal Wall

If incus involved with cholesteatoma: incudostapedial joint identified through facial recess, cut, and incus removed
Posterior canal wall taken down with rongeur
Facial ridge lowered until thin bone layer remains over vertical facial nerve segment
Chorda tympani nerve is sacrificed
Disease removed from oval window region and horizontal facial nerve segment
Malleus (or remnant) removed by cutting tensor tympani tendon at cochleariform process - provides access to anterior epitympanum
Anterior epitympanum drilled flush with anterior canal wall
Inferior canal wall drilled until confluent with mastoid tip (no bony overhang = avoids "sink trap")

Key Anatomical Landmarks and Goals

Anterior buttress (posterior canal wall meets tegmen) - totally removed for smooth continuity between mastoid tegmen and tegmen tympani
Posterior buttress (posterior canal wall meets EAC floor lateral to facial nerve) - also removed
Facial ridge lowered to fallopian canal - improves sinus tympani and hypotympanum exposure
Sinus tympani - most difficult area; if disease present and stapes absent, further dissection required
Final result: one large continuous cavity with floor of mastoid cavity flush with floor of bony EAC

Tympanoplasty (the "Modification")

The critical step distinguishing MRM from radical mastoidectomy
Tympanic membrane reconstructed using harvested temporalis fascia/areolar tissue
This seals off the middle ear mucosa and eliminates the expected intermittent discharge from exposed mucosa
Ossicular reconstruction performed if sufficient remnants remain (hearing secondary consideration)

Meatoplasty

Mandatory for all open cavity procedures
Enlarges the ear canal meatus to allow adequate postoperative inspection and cleaning of the cavity
A poorly performed MRM is characterized by: incomplete removal of posterior canal wall, high facial ridge, inadequate meatoplasty

Intraoperative Images

Bondy Modified Mastoid Cavity (Shambaugh Fig. A-21): external canal wall removed with tympanic membrane and ossicular chain preserved:

Bondy modified mastoid cavity - tympanic membrane and ossicular chain preserved

Full Modified Radical Mastoid Cavity (Shambaugh Fig. A-22): tympanic membrane removed, canal wall lowered to vertical facial nerve, cavity saucerized anterosuperiorly and posteroinferiorly:

Modified radical mastoid cavity - canal wall lowered to facial nerve

Intraoperative endoscopy showing facial nerve canal exposure (a), sigmoid sinus wall (b), and cartilage ossicular reconstruction - Type III tympanoplasty (c):

Intraoperative steps - facial nerve, sigmoid sinus, ossicular reconstruction

Complications

Category	Complication
Intraoperative	Facial nerve injury, sensorineural hearing loss (labyrinthine fistula), CSF leak (dural tear), sigmoid sinus injury
Early postoperative	Wound infection, hematoma, vertigo
Late	Residual/recurrent cholesteatoma (esp. sinus tympani), chronic cavity discharge, cavity problems requiring revision, caloric vestibular reaction to water

Postoperative Cavity Care

Lifelong periodic cleaning of the mastoid cavity (office visits)
Avoidance of water entry (caloric vertigo effect with water exposure)
This is the major disadvantage compared to canal-wall-up technique
Patients counseled preoperatively about this requirement

MRM vs. Canal-Wall-Up (CWU) - Key Comparison

MRM (Canal-Wall-Down) Advantages:

Single-stage procedure in most cases
No need for planned second-look surgery
Lower recurrence risk (better visualization)
Less demanding technically

MRM Disadvantages:

Lifelong cavity cleaning
No water in ear (activity restriction)
Caloric vertigo risk with water
Larger surgical cavity
Poorer hearing rehabilitation potential

The staged CWU technique is preferred by experienced otologic surgeons when technically feasible, as it eliminates periodic cleaning, avoids caloric vertigo, and offers better hearing outcomes. MRM is recommended for the occasional otologic surgeon, extensive disease, or patients who cannot comply with staged surgery.

Shambaugh Surgery of the Ear, p. 541-544

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