Indications and Techniquein Mastoidectomy

Marc Bennett, MD*, Frank Warren, MD,David Haynes, MD

The Otology Group, Otolaryngology Head & Neck Surgery, Vanderbilt University,

300 20th Avenue North, Suite 502, Nashville, TN 37203, USA

Approximately 350 years have passed since the rst published report ofa mastoidectomy by Riolan the Younger. Many changes have occurredover the subsequent years, especially since the advent of the operatingmicroscope 50 years ago. This report focuses on mastoid surgery as it relatesto chronic ear disease as well as providing access for a variety of other sur-gical procedures. We reect on the current status and indications of theprocedure as well as common complications.

History

Chronic and suppurative infections of the mastoid have been described aslong ago as ancient Greece. However, it was not until mid 17th centurywhen Riolan the Younger described the rst trephination procedure ofthe mastoid. The subsequent 200 years did not produce many signicant ad-vances until Fielitz and Petit reported multiple cases of mastoid trephina-tions for acute abscesses in the late 18th century. These procedures fellout of favor for more than 100 years until Schwartze and Eysell [1] popular-ized the cortical mastoidectomy in 1873. It was eective for draining acuteinfections; however, it did little to treat chronic infections of the ear. In1890, Zaufal [2] described the rst radical mastoidectomy removing thesuperior and posterior ear canal, tympanic membrane, and ossicles in an at-

Otolaryngol Clin N Am

39 (2006) 10951113tempt to eliminate infection, externalize disease, and create a dry ear. Bondyrevised the technique by leaving the uninvolved middle ear alone and exte-riorizing the epitympanum [3].

* Corresponding author.

E-mail address: Marc.Bennett@vanderbilt.edu (M. Bennett).

0030-6665/06/$ - see front matter 2006 Elsevier Inc. All rights reserved.doi:10.1016/j.otc.2006.08.012 oto.theclinics.com

The introduction of the Zeiss otologic operating scope in 1953made precisedissection possible. Soon thereafter, Wullstein described the rst attempts atreconstruction of the tympanic membrane via tympanoplasty [4]. Five yearslater, William House introduced intact canal wall mastoidectomy [5]. Sincethen, there have been multiple variations of the mastoidectomy described.

Indications

The goals of any chronic ear surgery are to create a dry, safe ear and pre-serve or restore hearing as much as possible. Although there are some abso-lute and relative indications for a mastoidectomy, the type of mastoidectomyis based on the extent of disease, preoperative health of the patient, the statusof the opposite ear, and both the surgeons and patients preference. Forchronic ear surgery, a mastoidectomy is performed to help eradicate diseaseand gain access to the antrum, attic, or middle ear. It also increases the air-containing space in continuity with the middle ear, allowing the middle earto better accommodate changes in pressure without tympanic membrane re-traction. Absolute indications include cholesteatomas or tumors with exten-sion into the mastoid bone. Relative indications include [6]:

History of profuse otorrhea Previous tympanoplasty failure Secondary acquired cholesteatoma Tympanic membrane perforations no correctable without the further ex-posure provided by a mastoidectomy

Although surgeons remain divided on the utility of the mastoidectomy inprimary cholesteatoma surgery and tympanic membrane perforation re-pairs, most agree to its utility in revision cases after graft failure. Generally,imaging and cholesteatoma size are not a determinate of what procedure isperformed.

Simple mastoidectomy

A simple or cortical mastoidectomy involves removing the mastoid cortexand some of the underlying air cells. Dissection may be supercial or pro-ceed to the mastoid antrum. It is used to unroof the mastoid cortex anddrain a coalescent mastoiditis with subperiosteal abscess.

Intact canal wall or complete mastoidectomy

The canal wall up mastoidectomy involves removing the mastoid air cellslateral to the facial nerve and otic capsule bone while preserving the poste-rior and superior external auditory canal walls. This technique aords

1096 BENNETT et alaccess to the epitympanum while maintaining the natural barrier betweenthe external auditory canal and mastoid cavity. In pediatric patients, this ap-proach is preferred generally to avoid the long-term problems associated

with canal wall down procedures. This approach can be combined with a fa-cial recess dissection for:

Removal of disease in the recess Better exposure of the posterior mesotympanum around the oval andround windows

Better visualization of the tympanic segment of the facial nerve Better middle ear aeration postoperativelyFor increased exposure, the facial recess can be extended inferiorly or su-

periorly to gain complete access to the hypotympanum and epitympanum. Ifcholesteatoma or tumor cannot be resected via this approach, the surgeryneeds to be converted to a canal wall down procedure. Occasionally, a mas-toidectomy may be used to identify and repair an injured facial nerve.

Modied radical mastoidectomy

Although the classic description of a modied radical mastoidectomy isthe atticotomy described by Bondy, most surgeons currently use the termto describe a canal wall down mastoidectomy with tympanic membranegrafting. There are both preoperative and intraoperative indications to re-move the auditory canal. Preoperative indications for a modied radicalmastoidectomy include [5] (1) disease in an only hearing ear, (2) patientswith poor general health making them an anesthetic risk, and (3) patientsin whom follow-up is problematic.

Some surgeons advocate a canal wall down after multiple failed attemptsat canal wall intact surgery [7]. The decision to remove the canal wall ismade intraoperatively when one of the following is encountered [8]: (1) un-reconstructible posterior external auditory canal defect, (2) labyrinthinestula where the matrix cannot be resected primarily, and (3) obstructinglow-lying middle fossa dura limiting epitympanic access. Again, cholestea-toma size is not a determining factor.

Radical mastoidectomy

A radical mastoidectomy is performed in patients with severe eustachiantube dysfunction, irreversible middle ear disease, or unresectable cholestea-toma or tumors. The procedure leaves middle ear and mastoid air cells ex-teriorized as a single cavity with no attempt at reconstruction. Theeustachian tube is occluded and both the malleus and incus are removed. Be-cause the middle ear is not reconstructed, the expectation is that surround-ing squamous epithelium will overgrow the middle ear and mastoid cavity.

1097MASTOIDECTOMYMastoid obliteration

Mastoid obliteration involves overclosing the external auditory canal inblind sac fashion and obliterating the cavity with autologous bone, bone

pate, vascularized aps, or abdominal fat. It is used in advanced cases inwhich the ear continues to drain despite multiple prior attempts at canalwall down surgery. Obliteration may also be indicated in cases of chronicsuppurative otitis media in which there is extensive dural dehiscence withor without cerebrospinal uid leakage.

Canal wall up versus down

The controversy over canal wall up versus down surgery has been on-going for nearly half a century. Although there are multiple indicationsto remove the canal wall, the decision is usually individualized. Most sur-geons prefer to avoid a cavity if possible. The primary advantage of a ca-nal wall down procedure is increased visibility and access to themesotympanum and epitympanum, which allows disease resection and re-construction to be accomplished in a single stage. This increased exposureaccounts for reduced rates of recurrences versus intact canal wall proce-dures [9]. However, postoperative care is more intense in the canal walldown surgery both in the immediate postoperative period and long-term. Serial debridements of the cavity and frequently antibiotic dropirrigation are often required. In contrast, the intact canal wall mastoidec-tomy maintains the natural anatomy and heals more quickly than themodied radical mastoidectomy. Canal wall intact procedures do not re-quire regular debridements, and hearing outcomes tend to be slightly im-proved over canal wall down procedures [10]. However, poorerintraoperative exposure and the recreation of a middle ear space increasethe potential for recurrent or residual disease after intact canal wallprocedures.

Preoperative evaluation

Preoperative planning includes a comprehensive head and neck exami-nation with an otomicroscopic examination. Active infections are treatedaggressively with topical antibiotic drops before surgery. Bilateral full au-diometric evaluation is performed in all cases. Although computed tomog-raphy scans can help delineate the bony anatomy of the temporal bone,this evaluation is not necessary in most patients. They are especially usefulin revision surgery and in patients with symptoms consistent with a labyrin-thine stula. All patients should be encouraged to stop smoking because itincreases recurrence rates over nonsmokers [9]. Sinonasal disease is treatedaggressively. Adult patients with signicant symptoms are tested and

1098 BENNETT et altreated for seasonal allergies. In children, preoperative adenoid assessmentmay be necessary and when appropriate, adenoidectomy should be per-formed 1 month before ear surgery.

Preparation

Anesthesia is given without paralytic agents. Facial nerve bipolar elec-trodes are placed into the orbicularis oculi and oris muscles for monitoringof the facial nerve throughout the case. The tragus and the area just behindthe postauricular sulcus are injected with 2% lidocaine with 1:100,000 epi-nephrine about 10 minutes before the start of the case to allow proper he-mostasis. The periauricular hair is cleansed with a hibiclens shampoo andthe patients ear is prepped and draped in the usual sterile fashion. Antibi-otics are routinely given preoperatively to reduce infection risks [11]. Ste-roids are also often used to reduce postoperative nausea.

Surgical incisions

Canal incisions

Each case starts with a detailed examination of the tympanic membrane.With the exception of cochlear implantation, temporal bone resection, andskull base procedures, transcanal injection of the posterior ear canal with2% lidocaine and 1:50,000 epinephrine is performed. The ear is copiouslyirrigated with saline solution impregnated with antibiotic and desquamateddebris in the external auditory canal is removed. Fig. 1 shows the vascularstrip incisions. A radial incision is made in the tympanomastoid and thentympanosquamous suture lines. The dependent or inferior cut is always per-formed rst to avoid blood obscuring future incisions. These incisions arethen connected by a medial incision approximately 1 to 2 mm lateral tothe annulus. Just medial to the bony-cartilaginous junction, a radial incisionis made from the tympanomastoid suture line to the inferior aspect of theexternal auditory canal.

1099MASTOIDECTOMYFig. 1. Vascular strip incisions. (A) tympanomastoid suture line, (B) tympanosquamous suture

line, (C) medial incision, (D) radial incision.

Mastoid incisions

The standard postauricular incision and the endaural incision are the twobasic incisions for access to the mastoid.

Postauricular incision

A postauricular incision as shown in Fig. 2 is the method most widely usedto gain access to the mastoid. The incision spans from the helical rim to themastoid tip and is well hidden in the postauricular region. It rarely causes anyvisible scarring. The incision should be about 1 cm behind the postauricularcrease to avoid unsightly deepening of the sulcus, which can occur when in-cisions are placed directly in the crease. The incision is more posterior inyoung children to avoid a supercial facial nerve near the mastoid tip.

The incision is made through the skin with a scalpel. An avascular planeis elevated anteriorly toward the external auditory canal just below the sub-dermal fat, leaving a layer of loose areolar tissue on the temporalis fascia.This plane is developed down to the mastoid tip. The attachments of thesternocleidomastoid muscle can be separated from the mastoid tip for in-creased exposure during skull base cases, but usually these attachmentsare left intact to reduce postoperative discomfort.

A self retaining retractor is spread over the temporalis muscle. As shown inFig. 3, a large graft is harvested with a scalpel and scissors. This tissue often isscarce in revision surgery and if not present, a true temporalis fascial graft canbe harvested. For proper healing, this graft must be thinned of all muscle andfat attachments. If the temporalis fascia is unavailable, tragal perichondriumor periosteum medial to the temporalis muscle may be harvested for grafting.Autologous veins or alloderm may also be used for grafting in rare cases [12].

As shown by the dashed lines in Fig. 3, T shaped incisions are thenmade through the mastoid periosteum with electrocautery. The horizontalincision is made just below the temporalis muscle in the linea temporalis.A second incision is made perpendicular to the rst in the middle of the

1100 BENNETT et alFig. 2. Postauricular incision.

mastoid extending from the temporalis muscle to the mastoid tip. A Lem-pert elevator is then used to elevate the periosteum posteriorly over the sig-moid sinus, superiorly over the tegmen, and anteriorly to the suprameatalspine of Henle where the vascular strip is identied and reected laterally.Two self retaining retractors are then placed in orthogonal directions asshown in Fig. 4. In revision surgery, careful palpation of the underlyingbone will often identify a potentially unprotected sigmoid sinus or dura.The incision is also modied to a C shaped incision at the posterior aspectof the previously dissected mastoid cavity. In younger children, elevation in-ferior to the external auditory canal can potentially injure a lateralized facialnerve near the stylomastoid foramen.

Lempert incision

Endaural incisions have been used for more than 100 years. Lempert pop-ularized this approach in the mid 1930s. An incision is made down to the

Fig. 3. Fascial graft harvest and periosteal incisions.

1101MASTOIDECTOMYFig. 4. Mastoid surface anatomy.

mastoid bone in the lateral external auditory canal between the tragus andthe helical crus. Because exposure can only be obtained of the anterior su-perior part of the mastoid, these incisions have fallen out of favor for mas-toidectomies; however, some surgeons continue to use these incisions tofacilitate exposure of the middle ear in transcanal surgery.

Techniques

Basics

All drilling is done under the microscope with binocular vision. Constantirrigation is critical to prevent thermal damage from the drill bits. A varietyof surgical drills exist for mastoidectomy, but a high-speed, comfortable,and reliable drill system is crucial. In the past, air-powered systems werethe norm, but recently the development of high-speed electrical systems oereasier setup, eciency, and less noise than the air powered systems.

A variety of burs exist, ranging from those that aggressively remove boneto those used for ne polishing of structures like the facial nerve. Larger bitsare always preferred as they oer better control and easier removal of bone;however, drill bits should not be so large as to obstruct visualization duringthe dissection. Initially, cutting burs are used to removed bone and identifyimportant landmarks. Diamond burrs are then used for more delicate pro-cedures like removing the last layer of bone over sigmoid sinus or facialnerve. As dissection continues, smaller burrs will be required as spacebecomes limited. Periodic irrigation of the surgical eld with saline solutionreduces bleeding and washes squamous debris from wound.

Surface anatomy

An understanding of the temporal bone anatomy is important to avoidinjuring vital structures. The surface landmarks of the mastoid bone shownin Fig. 4 not only dene the boundaries of the mastoid bone, but approxi-mate important deep structures. The spine of Henle is the anterior extentof dissection. This protuberance extends supercially from the posterior su-perior bony ear canal and approximates the location of the underlying mas-toid antrum. Superiorly, the linea temporalis, the inferior border of thetemporalis muscle, approximates the lowest level of the tegmen or oor ofthe middle fossa. The mastoid tip is the inferior limit of dissection.

Complete mastoidectomy

The key to a safe dissection is identifying key structures. Identifying thetegmen, external auditory canal, sigmoid sinus, middle ear ossicles, and

1102 BENNETT et alfacial nerve is the easiest and safest way to ensure their preservation.As indicated by Fig. 5, dissection starts high in the mastoid cortex, re-

moving bone along the linea temporalis until a thin layer of tegmen bone

is left over the middle fossa dura, remembering that tegmen height is vari-able depending on mastoid pneumatization. Next, a cut perpendicular tothe rst and tangential to the external auditory canal is made from the zy-gomatic root to the mastoid tip. Finally, a cut is made from the mastoid tipto the sinodural angle. Dissection is continued along these three planes, sau-cerizing the lateral surface of the temporal bone from the middle fossa teg-men to the mastoid tip and from the ear canal to the sigmoid, keeping thedeepest part of the dissection in the anterior superior mastoid directlyover the mastoid antrum. There is no attempt to keep the mastoid small.The next structure visualized deep in the mastoid cavity is Korners septum,the remnant of the petrosquamous suture line. Once through Korners sep-tum, the lateral semicircular canal is visible on the medial side of the antrumas shown in Fig. 6. The otic capsule bone is easily distinguished from themastoid air cells by its smooth glistening appearance.

For proper exposure, it is critical at this point to thin the posterior exter-nal auditory canal. The lateral external auditory canal is thinned from be-hind to the base of the spine of Henle. This thickness is carried mediallyto the level of the mastoid antrum. The superior external auditory canal isthinned similarly, and the bone between the middle fossa tegmen and supe-rior ear canal is removed to open the zygomatic root. As dissection is con-tinued medially, the epitympanum is opened widely and both the incus andmalleus are visualized. Air cells lateral to the labyrinth are exenterated downthe mastoid tip where the digastric ridge is identied. At the completion of

Fig. 5. Drill cuts used in start of mastoidectomy. (A) Thin layer of tegmen bone is left over the

middle fossa dura, remembering that tegmen height is variable depending on mastoid pneuma-

tization. Cut (B) perpendicular to the rst and tangential to the external auditory canal is made

from the zygomatic root to the mastoid tip. Cut (C) is made from the mastoid tip to the

sinodural angle.

1103MASTOIDECTOMYthe procedure, the middle and posterior fossa plates, sigmoid sinus, poste-rior external auditory canal, and bony labyrinth are all skeletonized.

For endolymphatic sac procedures, the sigmoid sinus is decompressedand the jugular bulb identied. The labyrinth is skeletonized, and the

dura between Donaldsons line, a line drawn as the posterior extension ofthe lateral semicircular canal, and the jugular bulb is exposed. The endolym-phatic sac and duct are identied and decompressed carefully or openedover the underlying dura.

At the completion of the procedure, the mastoid periosteum is reapproxi-mated with several interrupted 3-0 Vicryl sutures, and the skin is closed withinterrupted subcuticular 4-0 Vicryl sutures. The wound is then covered witha piece of telfa, several 4 4s, and a Glasscock dressing. The mastoid defectrarely causes any aesthetic concerns, but recently surgeons have attemptedto reconstruct the mastoid cortex with titanium mesh [13].

Facial recess or posterior tympanotomy

As seen in Fig. 7, the facial recess is an inverted triangle bounded poste-riomedially by the facial nerve, anterolaterally by the chorda tympani nerve,and superiorly by the incus buttress. The rst step in safely performing a fa-cial recess is to ensure that the posterior external auditory canal is thinnedappropriately at the end of a complete mastoidectomy. The next step is iden-tication of the facial nerve using previously found landmarks including thelateral semicircular canal, short process of the incus, and digastric ridge. Thefacial nerve is always found inferomedial to the lateral semicircular canal.As shown in Fig. 7, a line drawn as the extension of the short process ofthe incus approximates the facial recess.

Using a large diamond burr and copious amounts of irrigation, the facialnerve is identied throughout its entire mastoid course, from the second

Fig. 6. Complete mastoidectomy in cholesteatoma dissection. Asterisk indicates lateral semicir-

cular canal.

1104 BENNETT et algenu just inferior to the lateral semicircular canal to the stylomastoid fora-men. Using strokes parallel to the direction of the nerve, the nerve is tracedout, leaving a thin layer of the fallopian canal bone intact over the nerve.

The surgeon must be wary of a lack of bony covering, or dehiscent, facialnerve in the mastoid. Invariably, there are several small vessels aroundthe facial nerve that bleed during dissection near the nerve that usuallycan be controlled by the diamond burr or bipolar cautery. Next, the chordatympani nerve is identied as the anterior branch of the facial nerve 4 to 5mm proximal to the stylomastoid foramen. Dissection proceeds between themedial facial nerve and lateral chorda tympani nerve superiorly where therecess is the widest until the middle ear is entered. A short bridge of bone,the incus buttress, is left in the superior part of the facial recess to protectthe incus from the drill and maintain the support for the incus.

Extended facial recess

The facial recess can be extended after a complete mastoidectomy witha facial recess both inferiorly and superiorly. Superiorly, the incus buttresscan be removed with a small diamond burr. After removal of the incusand head of the malleus, the entire epitympanum can be accessed. Dissectioncan proceed anteriorly to the temporomandibular joint.

Inferiorly, an extended facial recess can expose the entire hypotympanumas shown in Fig. 8. The chorda tympani nerve is skeletonized and sacricedsharply to avoid retrograde trauma to the facial nerve. As shown in Fig. 8,dissection proceeds between the facial nerve and the tympanic membraneannulus as far anteriorly as the parotid fascia. Identication of the jugularbulb in this approach often helps avoid inadvertent injury.

Fig. 7. Facial recess. (dashed line) Short process of the incus helps identify the facial recess.

1105MASTOIDECTOMYModied radical mastoidectomy

The goal in creating a modied radical mastoidectomy is to createa smooth, self-cleaning cavity with no corners, edges, or depressions in

which debris can accumulate. As shown in Fig. 9, the keys to the procedureinclude [7]:

Aggressive saucerization of the mastoid Eliminating irregularities or overhangs in the bone Removing the posterior bony external auditory canal down to the levelof the facial nerve

Creating a large meatusThe modied radical mastoidectomy procedure starts after a complete

mastoidectomy and identication of the mastoid segment of the facial nerve.The incudostapedial joint is separated, and both the incus and malleus areremoved. The external auditory canal is then removed completely to thelevel of the fallopian canal, rst with a large cutting burr and later with a di-amond burr. If the air cells in the mastoid tip are diseased, they are com-pletely exenterated to avoid dependent tip infections. If the mastoid is

Fig. 8. Inferior extended facial recess. Asterisks indicate sacriced chorda tympani nerves.

1106 BENNETT et alFig. 9. Modied radical mastoidectomy. Asterisk indicates low facial ridge. Arrowheads

indicate smooth junction of ear canal plus mastoid cavity.

well aerated, it is often helpful to reduce the size of the cavity by removingthe lateral aspect of the mastoid tip, allowing the soft tissue to cave in andauto-obliterate some of the cavity. As shown by the arrowheads in Fig. 9,both the oor and roof of the medial ear canal are then drilled ush tothe anterior ear canal. This creates a smooth transition between the ear ca-nal and tegmen superiorly and mastoid tip inferiorly. Care must be used in-feriorly to avoid injury to a high jugular bulb in the hypotympanum. Theossicular chain may be reconstructed and a large fascial graft is used to rec-reate the tympanic membrane.

A large meatoplasty is necessary for epithelialization of the cavity andeasier postoperative care. A postauricular approach is used to removenearly 30% to 40% of the conchal cartilage as shown by the trapezoidalwedge of cartilage between lines A and B in Fig. 10. This allows posteriorreection of the Korners ap without deforming the auricle. Electrocauteryis used to divide the subcutaneous tissues of the auricle in a half-moonshape until the conchal cartilage is encountered. The cartilage is then ex-posed medially to about the bony cartilaginous junction. A curvilinear in-cision is made through the cartilage as shown in Fig. 11. Retrogradeelevation of the deep perichondrium with a freer elevator is then performed,and a crescent-shaped wedge of cartilage is removed. A small portion of the

1107MASTOIDECTOMYFig. 10. Meatoplasty. (A) Superior canal cut. (B) Inferior canal cut. Dashed line indicates area

of cartilage removed. The lower image shows Koerners ap reected posteriorly.

cartilage is cut to the appropriate size and thinned for use in the ossicularchain reconstruction.

A shown by the dashed lines in Fig. 10, meatal incisions A and B arethen made to enlarge the opening of the external auditory canal. A 15blade is placed in the ear canal and under direct vision an incision ismade through skin and subcutaneous tissue at 12 oclock in the externalauditory canal. As shown by line A, this incision is made from the bonycartilaginous junction to the incisura notch. An incision is made in the in-ferior aspect of the ear canal as depicted by line B. These incisions aremade through the skin and subcutaneous tissues in continuity with thepostauricular Koerners ap. As shown in Fig. 12, three subdermal suturesare placed between the Koerners ap and periosteum to reect the Koern-ers ap posteriorly. Tension in the sutures is adjusted to optimize the con-guration of the meatus. Generally, the meatus initially should be madeabout the size of the mastoid cavity because it will undergo about 25%contraction over time. A good approximation of this size is the surgeonsthumb.

The postauricular skin is then closed using several interrupted subcuticu-lar 4-0 Vicryl sutures. The mastoid and meatus are then lled with bactro-ban ointment. The wound is then covered with a telfa, several 4 4s anda Glasscock dressing or formal mastoid wrap.

Radical mastoidectomy

The radical mastoidectomy is an operation performed to eliminate all

Fig. 11. Conchal incisions.

1108 BENNETT et almiddle ear and mastoid disease through complete removal of mucosa, tym-panic membrane, annulus, malleus, and incus. Dissection is performed ina fashion similar to the modied radical mastoidectomy, but there is no

attempt at reconstruction or tympanic membrane grafting. In addition, theeustachian tube is occluded with a fascial plug.

Alternative procedures

Recently, several alternative procedures to the standard mastoidectomyhave been described. Dornhoer [9] has described an intact canal wall mas-toidectomy in which removal of the posterior superior external auditory ca-nal provides better epitympanic exposure. It also allows for dissection ofcholesteatoma sacs in continuity without the obstruction of the ear canal.The canal defect is then reconstructed with conchal cartilage to maintainthe natural barrier between the external auditory canal and mastoid cavity.The cartilage appears to remain stable over time, and there is a low rate ofpostoperative complications or recurrences.

A recent variation of the modied radical mastoidectomy has been pro-posed recently by Gantz and Hansen [14] in which the posterior ear canal isremoved en bloc. This creates exposure for cholesteatoma dissection similarto a canal wall down mastoidectomy. Once dissection is complete, the poste-rior external auditory canal is replaced, and several large bone chips are usedto seal o the epitympanum. The mastoid cavity is then obliterated with bonepate, obviating the need for serial mastoid cavity care. Patients require hospi-talization for at least 2 days of intravenous antibiotics postoperatively [14].

Fig. 12. Koerners ap. Suture tension can be varied to optimize meatus.

1109MASTOIDECTOMYCholesteatoma dissection

For the sake of simplicity, this article will not address cholesteatoma dis-section in the middle ear. However, cholesteatoma sacs often extend into the

mastoid air cells. Before dissection, bone is removed circumferentiallyaround the cholesteatoma sac avoiding direct contact with the sac. Oncefully exposed, the cholesteatoma sac is opened and the squamous debris re-moved to facilitate dissection.

Because labyrinthine stulas are dicult to assess preoperatively, carefulexamination of medial surface of the cholesteatoma sac is performed, look-ing for attening of the lateral semicircular canal or defects in the medialwall of the cholesteatoma, which may indicate an underlying stula. Areasof suspected stula can also be palpated carefully with blunt instruments.Leaving a small matrix on the stula preserves labyrinthine function in93% of patients as opposed to only 80% if the matrix is removed [15]. Ifless than 2 mm of matrix is left, a canal wall intact procedure can be per-formed if a second stage is planned. A canal wall down procedure shouldbe performed if a large cholesteatoma matrix is left in the mastoid [16].

Postoperative care

Both immediate and long-term care are important in the mastoidectomypatient. Both nausea and pain are treated aggressively to make the patientcomfortable. Facial nerve function is tested and recorded. Patients are dis-charged with their dressings in place and are allowed to remove the dressingafter 24 hours. Patients are instructed to change cotton balls in their ear andkeep the postauricular incision clean. Follow-up is scheduled for 3 weeks atwhich time their ears are lightly debrided and the patient is started on anti-biotic drops. Gentian violet is often used on granulation tissue in liberalfashion in canal wall down cavities. Water precautions are maintained for2 months or until the ear drum is noted to be fully healed.

Complications

Facial nerve injury

Other than death, facial nerve injury is the most disturbing complicationof ear surgery. We monitor all otologic cases to aid in preservation of thefacial nerve; however, monitoring is not a substitute for the thoroughknowledge of the anatomy of the nerve. In primary surgery, surgical land-marks are usually present and identication of the nerve is easier. In revisionsurgery and congenital ears, normal landmarks may be absent, making iden-tication of the nerve more dicult.

If nerve injury is suspected intraoperatively, identication of the nerve isperformed. It is important to remember that the injury often extends beyond

1110 BENNETT et althe visible injury several millimeters in both directions, and 3 to 4mm of nerveshould be exposed both proximal and distal to the suspected site of injury us-ing a diamond burr. Injury to the epineurium or nerve sheath usually has no

long-term consequences [17]. If less than 40%of the nerve is injured and facialmuscle contraction can be elicited with small milliamp (!0.1) stimulation ofthe proximal segment of the nerve, no further treatment is necessary otherthan the decompression already performed, postoperative steroids and closefollow-up. If more than 50% of the nerve is injured, superior results may beachieved through nerve grafting [18]. This is often a dicult decision, anda consultation from a colleague is useful in prompt evaluation of the nerve.Primary reanastamosis through simple reapproximation in the fallopian ca-nal or several 9-0 sutures through the epineurium should be performed if thereis enough length of nerve present. If there is a segment of nerve missing, mo-bilization of the nerve may obtain the extra length needed for anastomosis. Ifmore length is still needed, a cable graft using the great auricular or sural nervemay be used.

Immediate facial paralysis in the postoperative period also requiresprompt evaluation. Several hours may pass to ensure paresis is not the resultof overzealous use of local anesthetic at the beginning of the case. If paral-ysis persists beyond 4 hours, prompt operative exploration of the nerve iswarranted. Postoperative care depends on intraoperative circumstancesand common sense; if the nerve was already decompressed in the operatingroom, observation may be appropriate. If the operative team has gone homeand an inexperienced team is present, it may be advisable to observe the pa-tient until the regular team is back in the morning. Referral may also be thebest option in these dicult cases depending on the experience and expertiseof the surgeon. Conservative management with steroids, antibiotics, andantivirals is warranted in all cases of delayed facial paralysis [19].

Hearing loss

Iatrogenic hearing loss may occur after mastoid surgery. Sensorineuralhearing loss (SNHL) may be the result of removal of cholesteatoma overlabyrinthine stulas or inadvertent contact between the drill and ossicularchain during dissection. Labyrinthitis may also lead to SNHL as inamma-tory cells enter the inner ear via the round or oval windows. Drill injuriesusually result in a high-frequency sensorineural hearing loss. Conductivehearing losses are usually observed. They can be owing to multiple etiologiesincluding middle ear adhesions, tympanic membrane perforation, middleear eusions, ossicular xation, or failed ossicular chain reconstruction.

Infection

Postoperative infections occur in 2% to 5% of mastoidectomies. Infec-tion may be the result of wound infection or continued chronic ear disease.Routine prophylaxis may not necessarily reduce postoperative infection

1111MASTOIDECTOMYrates [20]. Perichondritis occurs in approximately 1% of canal wall downprocedures; therefore, perioperative antibiotics are used routinely in theseprocedures. Aggressive intervention with debridement and topical

antibiotics will limit overall disgurement. Infections in a mastoid withexposed dura may predispose the patient to meningitis and brain abscesses.

Vertigo

Labyrinthine stulas and injuries during mastoid surgery may alter thevestibular responses of an ear. Chronic infection may also be a source of re-duced vestibular function. Although unilateral loss of vestibular functionmay occur, chronic disequilibrium is rare.

Intracranial injury

Exposure of dura generally is avoided but is not of consequence unlesslarge defects in the tegmen, dural abrasions, or cerebrospinal uid are en-countered. Repair is generally through layered closure with soft tissue sup-port including muscle and fascia grafts with brin glue. Emergence fromanesthesia must be controlled without bucking or rises in intracranialpressure.

Bleeding

Like any surgery, bleeding is a potential postoperative risk. In modiedradical and radical mastoidectomies, postoperative bleeding is greater owingto more soft tissue dissection; however, blood drains through the meatusand there is little risk for hematoma formation. Injury to large vascularstructures like the sigmoid sinus, jugular bulb, or large emissary veins man-dates immediate assessment. Bleeding often is controlled easily with gelfoamand gentle pressure. Hematomas may form from uncontrolled bleeding ormore often from vessels in vasospasm during the procedure, which startbleeding with coughing or straining in the postoperative period.

Canal defects

Small defects in the external auditory canal usually require no interven-tion. Defects greater than 0.5 cm may be xed with bone pate or cartilagegrafting often with overlying fascial grafts to prevent canal cholesteatomaformation.

Further readings

Cass S. Mastoid surgery. In: Operative Otolaryngology Head and Neck Surgery. 1997.

p. 128098.

Glasscock ME. Surgical technique for open mastoid procedures. Laryngoscope 1982;92:14402.

GlasscockME III, Haynes DS, Storper IS, et al. Surgery for chronic ear disease. In: Hughes GB,

1112 BENNETT et alPensak ML, editors. Clinical otology. New York: Thieme Medical Publishers; 1996.

p. 21532.

Haynes DS, Harley DH. Surgical management of chronic otitis media: beyond tympanostomy

tubes. Otolaryngol Clin N Am 2002;35:82739.

Jackson CG, Glasscock ME, Nissen AJ, et al. Open mastoid procedures: contemporary

indications and surgical technique. Laryngoscope 1985;95:103743.

Kaylie DM, Jackson CG.Revision Chronic Ear Surgery. Otol HeadNeck Surg 2006;134:44350.

McGrew BM, Glasscock ME. Impact of mastoidectomy on simple tympanic membrane

perforation repair. Laryngoscope 2004;114:50611.

Pillsbury HC III, Carrasco VN. Revision mastoidectomy. Arch Otolaryngol Head Neck Surg

1990;116:101922.

Smyth GD, Toner JG. Mastoidectomy: the canal wall down procedure. In: Otologic surgery.

p. 22639.

Syms MJ, Luxford WM. Management of cholesteatoma: status of the canal wall. Laryngoscope

2003;113(3):4438.

References

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Indications and Technique in MastoidectomyHistoryIndicationsSimple mastoidectomyIntact canal wall or complete mastoidectomyModified radical mastoidectomyRadical mastoidectomyMastoid obliterationCanal wall up versus down

Preoperative evaluationPreparationSurgical incisionsCanal incisionsMastoid incisionsPostauricular incisionLempert incision

TechniquesBasicsSurface anatomyComplete mastoidectomyFacial recess or posterior tympanotomyExtended facial recessModified radical mastoidectomyRadical mastoidectomyAlternative proceduresCholesteatoma dissection

Postoperative careComplicationsFacial nerve injuryHearing lossInfectionVertigoIntracranial injuryBleedingCanal defects

Further readingsReferences