Indications And Technique

Otolaryngol Clin N Am 39 (2006) 1095–1113

Indications and Technique in 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 first published report of a mastoidectomy by Riolan the Younger. Many changes have occurred over the subsequent years, especially since the advent of the operating microscope 50 years ago. This report focuses on mastoid surgery as it relates to chronic ear disease as well as providing access for a variety of other surgical procedures. We reflect on the current status and indications of the procedure as well as common complications.

History Chronic and suppurative infections of the mastoid have been described as long ago as ancient Greece. However, it was not until mid 17th century when Riolan the Younger described the first trephination procedure of the mastoid. The subsequent 200 years did not produce many significant advances until Fielitz and Petit reported multiple cases of mastoid trephinations for acute abscesses in the late 18th century. These procedures fell out of favor for more than 100 years until Schwartze and Eysell [1] popularized the cortical mastoidectomy in 1873. It was effective for draining acute infections; however, it did little to treat chronic infections of the ear. In 1890, Zaufal [2] described the first radical mastoidectomy removing the superior and posterior ear canal, tympanic membrane, and ossicles in an attempt to eliminate infection, externalize disease, and create a dry ear. Bondy revised the technique by leaving the uninvolved middle ear alone and exteriorizing the epitympanum [3].

* Corresponding author. E-mail address: [email protected] (M. Bennett). 0030-6665/06/$ - see front matter Ó 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.otc.2006.08.012

oto.theclinics.com

1096

BENNETT

et al

The introduction of the Zeiss otologic operating scope in 1953 made precise dissection possible. Soon thereafter, Wullstein described the first attempts at reconstruction of the tympanic membrane via tympanoplasty [4]. Five years later, William House introduced intact canal wall mastoidectomy [5]. Since then, 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 preserve or restore hearing as much as possible. Although there are some absolute and relative indications for a mastoidectomy, the type of mastoidectomy is based on the extent of disease, preoperative health of the patient, the status of the opposite ear, and both the surgeon’s and patient’s preference. For chronic ear surgery, a mastoidectomy is performed to help eradicate disease and gain access to the antrum, attic, or middle ear. It also increases the aircontaining space in continuity with the middle ear, allowing the middle ear to better accommodate changes in pressure without tympanic membrane retraction. Absolute indications include cholesteatomas or tumors with extension 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 exposure provided by a mastoidectomy

Although surgeons remain divided on the utility of the mastoidectomy in primary cholesteatoma surgery and tympanic membrane perforation repairs, most agree to its utility in revision cases after graft failure. Generally, imaging and cholesteatoma size are not a determinate of what procedure is performed. Simple mastoidectomy A simple or cortical mastoidectomy involves removing the mastoid cortex and some of the underlying air cells. Dissection may be superficial or proceed to the mastoid antrum. It is used to unroof the mastoid cortex and drain a coalescent mastoiditis with subperiosteal abscess. Intact canal wall or complete mastoidectomy The canal wall up mastoidectomy involves removing the mastoid air cells lateral to the facial nerve and otic capsule bone while preserving the posterior and superior external auditory canal walls. This technique affords access to the epitympanum while maintaining the natural barrier between the external auditory canal and mastoid cavity. In pediatric patients, this approach is preferred generally to avoid the long-term problems associated

MASTOIDECTOMY

1097

with canal wall down procedures. This approach can be combined with a facial recess dissection for:  Removal of disease in the recess  Better exposure of the posterior mesotympanum around the oval and round windows  Better visualization of the tympanic segment of the facial nerve  Better middle ear aeration postoperatively For increased exposure, the facial recess can be extended inferiorly or superiorly to gain complete access to the hypotympanum and epitympanum. If cholesteatoma or tumor cannot be resected via this approach, the surgery needs to be converted to a canal wall down procedure. Occasionally, a mastoidectomy may be used to identify and repair an injured facial nerve. Modified radical mastoidectomy Although the classic description of a modified radical mastoidectomy is the atticotomy described by Bondy, most surgeons currently use the term to describe a canal wall down mastoidectomy with tympanic membrane grafting. There are both preoperative and intraoperative indications to remove the auditory canal. Preoperative indications for a modified radical mastoidectomy include [5] (1) disease in an only hearing ear, (2) patients with poor general health making them an anesthetic risk, and (3) patients in whom follow-up is problematic. Some surgeons advocate a canal wall down after multiple failed attempts at canal wall intact surgery [7]. The decision to remove the canal wall is made intraoperatively when one of the following is encountered [8]: (1) unreconstructible posterior external auditory canal defect, (2) labyrinthine fistula where the matrix cannot be resected primarily, and (3) obstructing low-lying middle fossa dura limiting epitympanic access. Again, cholesteatoma size is not a determining factor. Radical mastoidectomy A radical mastoidectomy is performed in patients with severe eustachian tube dysfunction, irreversible middle ear disease, or unresectable cholesteatoma or tumors. The procedure leaves middle ear and mastoid air cells exteriorized as a single cavity with no attempt at reconstruction. The eustachian tube is occluded and both the malleus and incus are removed. Because the middle ear is not reconstructed, the expectation is that surrounding squamous epithelium will overgrow the middle ear and mastoid cavity. Mastoid obliteration Mastoid obliteration involves overclosing the external auditory canal in blind sac fashion and obliterating the cavity with autologous bone, bone

1098

BENNETT

et al

pate, vascularized flaps, or abdominal fat. It is used in advanced cases in which the ear continues to drain despite multiple prior attempts at canal wall down surgery. Obliteration may also be indicated in cases of chronic suppurative otitis media in which there is extensive dural dehiscence with or without cerebrospinal fluid leakage.

Canal wall up versus down The controversy over canal wall up versus down surgery has been ongoing for nearly half a century. Although there are multiple indications to remove the canal wall, the decision is usually individualized. Most surgeons prefer to avoid a cavity if possible. The primary advantage of a canal wall down procedure is increased visibility and access to the mesotympanum and epitympanum, which allows disease resection and reconstruction to be accomplished in a single stage. This increased exposure accounts for reduced rates of recurrences versus intact canal wall procedures [9]. However, postoperative care is more intense in the canal wall down surgery both in the immediate postoperative period and longterm. Serial debridements of the cavity and frequently antibiotic drop irrigation are often required. In contrast, the intact canal wall mastoidectomy maintains the natural anatomy and heals more quickly than the modified radical mastoidectomy. Canal wall intact procedures do not require regular debridements, and hearing outcomes tend to be slightly improved over canal wall down procedures [10]. However, poorer intraoperative exposure and the recreation of a middle ear space increase the potential for recurrent or residual disease after intact canal wall procedures.

Preoperative evaluation Preoperative planning includes a comprehensive head and neck examination with an otomicroscopic examination. Active infections are treated aggressively with topical antibiotic drops before surgery. Bilateral full audiometric evaluation is performed in all cases. Although computed tomography scans can help delineate the bony anatomy of the temporal bone, this evaluation is not necessary in most patients. They are especially useful in revision surgery and in patients with symptoms consistent with a labyrinthine fistula. All patients should be encouraged to stop smoking because it increases recurrence rates over nonsmokers [9]. Sinonasal disease is treated aggressively. Adult patients with significant symptoms are tested and treated for seasonal allergies. In children, preoperative adenoid assessment may be necessary and when appropriate, adenoidectomy should be performed 1 month before ear surgery.

MASTOIDECTOMY

1099

Preparation Anesthesia is given without paralytic agents. Facial nerve bipolar electrodes are placed into the orbicularis oculi and oris muscles for monitoring of the facial nerve throughout the case. The tragus and the area just behind the postauricular sulcus are injected with 2% lidocaine with 1:100,000 epinephrine about 10 minutes before the start of the case to allow proper hemostasis. The periauricular hair is cleansed with a hibiclens shampoo and the patient’s ear is prepped and draped in the usual sterile fashion. Antibiotics are routinely given preoperatively to reduce infection risks [11]. Steroids 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, and skull base procedures, transcanal injection of the posterior ear canal with 2% lidocaine and 1:50,000 epinephrine is performed. The ear is copiously irrigated with saline solution impregnated with antibiotic and desquamated debris in the external auditory canal is removed. Fig. 1 shows the vascular strip incisions. A radial incision is made in the tympanomastoid and then tympanosquamous suture lines. The dependent or inferior cut is always performed first to avoid blood obscuring future incisions. These incisions are then connected by a medial incision approximately 1 to 2 mm lateral to the annulus. Just medial to the bony-cartilaginous junction, a radial incision is made from the tympanomastoid suture line to the inferior aspect of the external auditory canal.

Fig. 1. Vascular strip incisions. (A) tympanomastoid suture line, (B) tympanosquamous suture line, (C) medial incision, (D) radial incision.

1100

BENNETT

et al

Mastoid incisions The standard postauricular incision and the endaural incision are the two basic incisions for access to the mastoid. Postauricular incision A postauricular incision as shown in Fig. 2 is the method most widely used to gain access to the mastoid. The incision spans from the helical rim to the mastoid tip and is well hidden in the postauricular region. It rarely causes any visible scarring. The incision should be about 1 cm behind the postauricular crease to avoid unsightly deepening of the sulcus, which can occur when incisions are placed directly in the crease. The incision is more posterior in young children to avoid a superficial facial nerve near the mastoid tip. The incision is made through the skin with a scalpel. An avascular plane is elevated anteriorly toward the external auditory canal just below the subdermal fat, leaving a layer of loose areolar tissue on the temporalis fascia. This plane is developed down to the mastoid tip. The attachments of the sternocleidomastoid muscle can be separated from the mastoid tip for increased exposure during skull base cases, but usually these attachments are left intact to reduce postoperative discomfort. A self retaining retractor is spread over the temporalis muscle. As shown in Fig. 3, a large graft is harvested with a scalpel and scissors. This tissue often is scarce in revision surgery and if not present, a true temporalis fascial graft can be harvested. For proper healing, this graft must be thinned of all muscle and fat attachments. If the temporalis fascia is unavailable, tragal perichondrium or 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 then made through the mastoid periosteum with electrocautery. The horizontal incision is made just below the temporalis muscle in the linea temporalis. A second incision is made perpendicular to the first in the middle of the

Fig. 2. Postauricular incision.

MASTOIDECTOMY

1101

Fig. 3. Fascial graft harvest and periosteal incisions.

mastoid extending from the temporalis muscle to the mastoid tip. A Lempert elevator is then used to elevate the periosteum posteriorly over the sigmoid sinus, superiorly over the tegmen, and anteriorly to the suprameatal spine of Henle where the vascular strip is identified and reflected laterally. Two self retaining retractors are then placed in orthogonal directions as shown in Fig. 4. In revision surgery, careful palpation of the underlying bone will often identify a potentially unprotected sigmoid sinus or dura. The incision is also modified to a ‘‘C’’ shaped incision at the posterior aspect of the previously dissected mastoid cavity. In younger children, elevation inferior to the external auditory canal can potentially injure a lateralized facial nerve near the stylomastoid foramen. Lempert incision Endaural incisions have been used for more than 100 years. Lempert popularized this approach in the mid 1930s. An incision is made down to the

Fig. 4. Mastoid surface anatomy.

1102

BENNETT

et al

mastoid bone in the lateral external auditory canal between the tragus and the helical crus. Because exposure can only be obtained of the anterior superior part of the mastoid, these incisions have fallen out of favor for mastoidectomies; however, some surgeons continue to use these incisions to facilitate exposure of the middle ear in transcanal surgery. Techniques Basics All drilling is done under the microscope with binocular vision. Constant irrigation is critical to prevent thermal damage from the drill bits. A variety of surgical drills exist for mastoidectomy, but a high-speed, comfortable, and reliable drill system is crucial. In the past, air-powered systems were the norm, but recently the development of high-speed electrical systems offer easier setup, efficiency, and less noise than the air powered systems. A variety of burs exist, ranging from those that aggressively remove bone to those used for fine polishing of structures like the facial nerve. Larger bits are always preferred as they offer better control and easier removal of bone; however, drill bits should not be so large as to obstruct visualization during the dissection. Initially, cutting burs are used to removed bone and identify important landmarks. Diamond burrs are then used for more delicate procedures like removing the last layer of bone over sigmoid sinus or facial nerve. As dissection continues, smaller burrs will be required as space becomes limited. Periodic irrigation of the surgical field with saline solution reduces bleeding and washes squamous debris from wound. Surface anatomy An understanding of the temporal bone anatomy is important to avoid injuring vital structures. The surface landmarks of the mastoid bone shown in Fig. 4 not only define the boundaries of the mastoid bone, but approximate important deep structures. The spine of Henle is the anterior extent of dissection. This protuberance extends superficially from the posterior superior bony ear canal and approximates the location of the underlying mastoid antrum. Superiorly, the linea temporalis, the inferior border of the temporalis muscle, approximates the lowest level of the tegmen or floor of the middle fossa. The mastoid tip is the inferior limit of dissection. Complete mastoidectomy The key to a safe dissection is identifying key structures. Identifying the tegmen, external auditory canal, sigmoid sinus, middle ear ossicles, and facial nerve is the easiest and safest way to ensure their preservation. As indicated by Fig. 5, dissection starts high in the mastoid cortex, removing bone along the linea temporalis until a thin layer of tegmen bone

MASTOIDECTOMY

1103

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 pneumatization. Cut (B) perpendicular to the first 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.

is left over the middle fossa dura, remembering that tegmen height is variable depending on mastoid pneumatization. Next, a cut perpendicular to the first and tangential to the external auditory canal is made from the zygomatic root to the mastoid tip. Finally, a cut is made from the mastoid tip to the sinodural angle. Dissection is continued along these three planes, saucerizing the lateral surface of the temporal bone from the middle fossa tegmen to the mastoid tip and from the ear canal to the sigmoid, keeping the deepest part of the dissection in the anterior superior mastoid directly over the mastoid antrum. There is no attempt to keep the mastoid small. The next structure visualized deep in the mastoid cavity is Ko¨rner’s septum, the remnant of the petrosquamous suture line. Once through Ko¨rner’s septum, the lateral semicircular canal is visible on the medial side of the antrum as shown in Fig. 6. The otic capsule bone is easily distinguished from the mastoid air cells by its smooth glistening appearance. For proper exposure, it is critical at this point to thin the posterior external auditory canal. The lateral external auditory canal is thinned from behind to the base of the spine of Henle. This thickness is carried medially to the level of the mastoid antrum. The superior external auditory canal is thinned similarly, and the bone between the middle fossa tegmen and superior ear canal is removed to open the zygomatic root. As dissection is continued medially, the epitympanum is opened widely and both the incus and malleus are visualized. Air cells lateral to the labyrinth are exenterated down the mastoid tip where the digastric ridge is identified. At the completion of the procedure, the middle and posterior fossa plates, sigmoid sinus, posterior external auditory canal, and bony labyrinth are all skeletonized. For endolymphatic sac procedures, the sigmoid sinus is decompressed and the jugular bulb identified. The labyrinth is skeletonized, and the

1104

BENNETT

et al

Fig. 6. Complete mastoidectomy in cholesteatoma dissection. Asterisk indicates lateral semicircular canal.

dura between Donaldson’s line, a line drawn as the posterior extension of the lateral semicircular canal, and the jugular bulb is exposed. The endolymphatic sac and duct are identified and decompressed carefully or opened over the underlying dura. At the completion of the procedure, the mastoid periosteum is reapproximated with several interrupted 3-0 Vicryl sutures, and the skin is closed with interrupted subcuticular 4-0 Vicryl sutures. The wound is then covered with a piece of telfa, several 4  4s, and a Glasscock dressing. The mastoid defect rarely causes any aesthetic concerns, but recently surgeons have attempted to 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 posteriomedially by the facial nerve, anterolaterally by the chorda tympani nerve, and superiorly by the incus buttress. The first step in safely performing a facial recess is to ensure that the posterior external auditory canal is thinned appropriately at the end of a complete mastoidectomy. The next step is identification of the facial nerve using previously found landmarks including the lateral semicircular canal, short process of the incus, and digastric ridge. The facial 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 of the incus approximates the facial recess. Using a large diamond burr and copious amounts of irrigation, the facial nerve is identified throughout its entire mastoid course, from the second genu just inferior to the lateral semicircular canal to the stylomastoid foramen. Using strokes parallel to the direction of the nerve, the nerve is traced out, leaving a thin layer of the fallopian canal bone intact over the nerve.

MASTOIDECTOMY

1105

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

The surgeon must be wary of a lack of bony covering, or dehiscent, facial nerve in the mastoid. Invariably, there are several small vessels around the facial nerve that bleed during dissection near the nerve that usually can be controlled by the diamond burr or bipolar cautery. Next, the chorda tympani nerve is identified as the anterior branch of the facial nerve 4 to 5 mm proximal to the stylomastoid foramen. Dissection proceeds between the medial facial nerve and lateral chorda tympani nerve superiorly where the recess 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 protect the incus from the drill and maintain the support for the incus. Extended facial recess The facial recess can be extended after a complete mastoidectomy with a facial recess both inferiorly and superiorly. Superiorly, the incus buttress can be removed with a small diamond burr. After removal of the incus and head of the malleus, the entire epitympanum can be accessed. Dissection can proceed anteriorly to the temporomandibular joint. Inferiorly, an extended facial recess can expose the entire hypotympanum as shown in Fig. 8. The chorda tympani nerve is skeletonized and sacrificed sharply to avoid retrograde trauma to the facial nerve. As shown in Fig. 8, dissection proceeds between the facial nerve and the tympanic membrane annulus as far anteriorly as the parotid fascia. Identification of the jugular bulb in this approach often helps avoid inadvertent injury. Modified radical mastoidectomy The goal in creating a modified radical mastoidectomy is to create a smooth, self-cleaning cavity with no corners, edges, or depressions in

1106

BENNETT

et al

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

which debris can accumulate. As shown in Fig. 9, the keys to the procedure include [7]:  Aggressive saucerization of the mastoid  Eliminating irregularities or overhangs in the bone  Removing the posterior bony external auditory canal down to the level of the facial nerve  Creating a large meatus The modified radical mastoidectomy procedure starts after a complete mastoidectomy and identification of the mastoid segment of the facial nerve. The incudostapedial joint is separated, and both the incus and malleus are removed. The external auditory canal is then removed completely to the level of the fallopian canal, first with a large cutting burr and later with a diamond burr. If the air cells in the mastoid tip are diseased, they are completely exenterated to avoid dependent tip infections. If the mastoid is

Fig. 9. Modified radical mastoidectomy. Asterisk indicates low facial ridge. Arrowheads indicate smooth junction of ear canal plus mastoid cavity.

MASTOIDECTOMY

1107

well aerated, it is often helpful to reduce the size of the cavity by removing the lateral aspect of the mastoid tip, allowing the soft tissue to ‘‘cave in’’ and auto-obliterate some of the cavity. As shown by the arrowheads in Fig. 9, both the floor and roof of the medial ear canal are then drilled flush to the anterior ear canal. This creates a smooth transition between the ear canal and tegmen superiorly and mastoid tip inferiorly. Care must be used inferiorly to avoid injury to a high jugular bulb in the hypotympanum. The ossicular chain may be reconstructed and a large fascial graft is used to recreate the tympanic membrane. A large meatoplasty is necessary for epithelialization of the cavity and easier postoperative care. A postauricular approach is used to remove nearly 30% to 40% of the conchal cartilage as shown by the trapezoidal wedge of cartilage between lines A and B in Fig. 10. This allows posterior reflection of the Ko¨rner’s flap without deforming the auricle. Electrocautery is used to divide the subcutaneous tissues of the auricle in a half-moon shape until the conchal cartilage is encountered. The cartilage is then exposed medially to about the bony cartilaginous junction. A curvilinear incision is made through the cartilage as shown in Fig. 11. Retrograde elevation 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

Fig. 10. Meatoplasty. (A) Superior canal cut. (B) Inferior canal cut. Dashed line indicates area of cartilage removed. The lower image shows Koerner’s flap reflected posteriorly.

1108

BENNETT

et al

Fig. 11. Conchal incisions.

cartilage is cut to the appropriate size and thinned for use in the ossicular chain reconstruction. A shown by the dashed lines in Fig. 10, meatal incisions A and B are then made to enlarge the opening of the external auditory canal. A 15 blade is placed in the ear canal and under direct vision an incision is made through skin and subcutaneous tissue at 12 o’clock in the external auditory canal. As shown by line A, this incision is made from the bony cartilaginous junction to the incisura notch. An incision is made in the inferior aspect of the ear canal as depicted by line B. These incisions are made through the skin and subcutaneous tissues in continuity with the postauricular Koerner’s flap. As shown in Fig. 12, three subdermal sutures are placed between the Koerner’s flap and periosteum to reflect the Koerner’s flap posteriorly. Tension in the sutures is adjusted to optimize the configuration of the meatus. Generally, the meatus initially should be made about the size of the mastoid cavity because it will undergo about 25% contraction over time. A good approximation of this size is the surgeon’s thumb. The postauricular skin is then closed using several interrupted subcuticular 4-0 Vicryl sutures. The mastoid and meatus are then filled with bactroban ointment. The wound is then covered with a telfa, several 4  4s and a Glasscock dressing or formal mastoid wrap. Radical mastoidectomy The radical mastoidectomy is an operation performed to eliminate all middle ear and mastoid disease through complete removal of mucosa, tympanic membrane, annulus, malleus, and incus. Dissection is performed in a fashion similar to the modified radical mastoidectomy, but there is no

MASTOIDECTOMY

1109

Fig. 12. Koerner’s flap. Suture tension can be varied to optimize meatus.

attempt at reconstruction or tympanic membrane grafting. In addition, the eustachian tube is occluded with a fascial plug. Alternative procedures Recently, several alternative procedures to the standard mastoidectomy have been described. Dornhoffer [9] has described an intact canal wall mastoidectomy in which removal of the posterior superior external auditory canal provides better epitympanic exposure. It also allows for dissection of cholesteatoma sacs in continuity without the obstruction of the ear canal. The canal defect is then reconstructed with conchal cartilage to maintain the natural barrier between the external auditory canal and mastoid cavity. The cartilage appears to remain stable over time, and there is a low rate of postoperative complications or recurrences. A recent variation of the modified radical mastoidectomy has been proposed recently by Gantz and Hansen [14] in which the posterior ear canal is removed en bloc. This creates exposure for cholesteatoma dissection similar to a canal wall down mastoidectomy. Once dissection is complete, the posterior external auditory canal is replaced, and several large bone chips are used to seal off the epitympanum. The mastoid cavity is then obliterated with bone pate, obviating the need for serial mastoid cavity care. Patients require hospitalization for at least 2 days of intravenous antibiotics postoperatively [14]. Cholesteatoma dissection For the sake of simplicity, this article will not address cholesteatoma dissection in the middle ear. However, cholesteatoma sacs often extend into the

1110

BENNETT

et al

mastoid air cells. Before dissection, bone is removed circumferentially around the cholesteatoma sac avoiding direct contact with the sac. Once fully exposed, the cholesteatoma sac is opened and the squamous debris removed to facilitate dissection. Because labyrinthine fistulas are difficult to assess preoperatively, careful examination of medial surface of the cholesteatoma sac is performed, looking for flattening of the lateral semicircular canal or defects in the medial wall of the cholesteatoma, which may indicate an underlying fistula. Areas of suspected fistula can also be palpated carefully with blunt instruments. Leaving a small matrix on the fistula preserves labyrinthine function in 93% of patients as opposed to only 80% if the matrix is removed [15]. If less than 2 mm of matrix is left, a canal wall intact procedure can be performed if a second stage is planned. A canal wall down procedure should be performed if a large cholesteatoma matrix is left in the mastoid [16].

Postoperative care Both immediate and long-term care are important in the mastoidectomy patient. Both nausea and pain are treated aggressively to make the patient comfortable. Facial nerve function is tested and recorded. Patients are discharged with their dressings in place and are allowed to remove the dressing after 24 hours. Patients are instructed to change cotton balls in their ear and keep the postauricular incision clean. Follow-up is scheduled for 3 weeks at which time their ears are lightly debrided and the patient is started on antibiotic drops. Gentian violet is often used on granulation tissue in liberal fashion in canal wall down cavities. Water precautions are maintained for 2 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 complication of ear surgery. We monitor all otologic cases to aid in preservation of the facial nerve; however, monitoring is not a substitute for the thorough knowledge of the anatomy of the nerve. In primary surgery, surgical landmarks are usually present and identification of the nerve is easier. In revision surgery and congenital ears, normal landmarks may be absent, making identification of the nerve more difficult. If nerve injury is suspected intraoperatively, identification of the nerve is performed. It is important to remember that the injury often extends beyond the visible injury several millimeters in both directions, and 3 to 4 mm of nerve should be exposed both proximal and distal to the suspected site of injury using a diamond burr. Injury to the epineurium or nerve sheath usually has no

MASTOIDECTOMY

1111

long-term consequences [17]. If less than 40% of the nerve is injured and facial muscle contraction can be elicited with small milliamp (!0.1) stimulation of the proximal segment of the nerve, no further treatment is necessary other than the decompression already performed, postoperative steroids and close follow-up. If more than 50% of the nerve is injured, superior results may be achieved through nerve grafting [18]. This is often a difficult decision, and a consultation from a colleague is useful in prompt evaluation of the nerve. Primary reanastamosis through simple reapproximation in the fallopian canal or several 9-0 sutures through the epineurium should be performed if there is enough length of nerve present. If there is a segment of nerve missing, mobilization of the nerve may obtain the extra length needed for anastomosis. If more length is still needed, a cable graft using the great auricular or sural nerve may be used. Immediate facial paralysis in the postoperative period also requires prompt evaluation. Several hours may pass to ensure paresis is not the result of overzealous use of local anesthetic at the beginning of the case. If paralysis persists beyond 4 hours, prompt operative exploration of the nerve is warranted. Postoperative care depends on intraoperative circumstances and common sense; if the nerve was already decompressed in the operating room, observation may be appropriate. If the operative team has gone home and an inexperienced team is present, it may be advisable to observe the patient until the regular team is back in the morning. Referral may also be the best option in these difficult cases depending on the experience and expertise of the surgeon. Conservative management with steroids, antibiotics, and antivirals is warranted in all cases of delayed facial paralysis [19]. Hearing loss Iatrogenic hearing loss may occur after mastoid surgery. Sensorineural hearing loss (SNHL) may be the result of removal of cholesteatoma over labyrinthine fistulas or inadvertent contact between the drill and ossicular chain during dissection. Labyrinthitis may also lead to SNHL as inflammatory cells enter the inner ear via the round or oval windows. Drill injuries usually result in a high-frequency sensorineural hearing loss. Conductive hearing losses are usually observed. They can be owing to multiple etiologies including middle ear adhesions, tympanic membrane perforation, middle ear effusions, ossicular fixation, or failed ossicular chain reconstruction. Infection Postoperative infections occur in 2% to 5% of mastoidectomies. Infection may be the result of wound infection or continued chronic ear disease. Routine prophylaxis may not necessarily reduce postoperative infection rates [20]. Perichondritis occurs in approximately 1% of canal wall down procedures; therefore, perioperative antibiotics are used routinely in these procedures. Aggressive intervention with debridement and topical

1112

BENNETT

et al

antibiotics will limit overall disfigurement. Infections in a mastoid with exposed dura may predispose the patient to meningitis and brain abscesses. Vertigo Labyrinthine fistulas and injuries during mastoid surgery may alter the vestibular responses of an ear. Chronic infection may also be a source of reduced vestibular function. Although unilateral loss of vestibular function may occur, chronic disequilibrium is rare. Intracranial injury Exposure of dura generally is avoided but is not of consequence unless large defects in the tegmen, dural abrasions, or cerebrospinal fluid are encountered. Repair is generally through layered closure with soft tissue support including muscle and fascia grafts with fibrin glue. Emergence from anesthesia must be controlled without bucking or rises in intracranial pressure. Bleeding Like any surgery, bleeding is a potential postoperative risk. In modified radical and radical mastoidectomies, postoperative bleeding is greater owing to more soft tissue dissection; however, blood drains through the meatus and there is little risk for hematoma formation. Injury to large vascular structures like the sigmoid sinus, jugular bulb, or large emissary veins mandates immediate assessment. Bleeding often is controlled easily with gelfoam and gentle pressure. Hematomas may form from uncontrolled bleeding or more often from vessels in vasospasm during the procedure, which start bleeding with coughing or straining in the postoperative period. Canal defects Small defects in the external auditory canal usually require no intervention. Defects greater than 0.5 cm may be fixed with bone pate or cartilage grafting often with overlying fascial grafts to prevent canal cholesteatoma formation. Further readings Cass S. Mastoid surgery. In: Operative Otolaryngology Head and Neck Surgery. 1997. p. 1280–98. Glasscock ME. Surgical technique for open mastoid procedures. Laryngoscope 1982;92:1440–2. Glasscock ME III, Haynes DS, Storper IS, et al. Surgery for chronic ear disease. In: Hughes GB, Pensak ML, editors. Clinical otology. New York: Thieme Medical Publishers; 1996. p. 215–32. Haynes DS, Harley DH. Surgical management of chronic otitis media: beyond tympanostomy tubes. Otolaryngol Clin N Am 2002;35:827–39.

MASTOIDECTOMY

1113

Jackson CG, Glasscock ME, Nissen AJ, et al. Open mastoid procedures: contemporary indications and surgical technique. Laryngoscope 1985;95:1037–43. Kaylie DM, Jackson CG. Revision Chronic Ear Surgery. Otol Head Neck Surg 2006;134:443–50. McGrew BM, Glasscock ME. Impact of mastoidectomy on simple tympanic membrane perforation repair. Laryngoscope 2004;114:506–11. Pillsbury HC III, Carrasco VN. Revision mastoidectomy. Arch Otolaryngol Head Neck Surg 1990;116:1019–22. Smyth GD, Toner JG. Mastoidectomy: the canal wall down procedure. In: Otologic surgery. p. 226–39. Syms MJ, Luxford WM. Management of cholesteatoma: status of the canal wall. Laryngoscope 2003;113(3):443–8.

References [1] Schwartze HH, Eysell CG. Ueber die Kunstliche eroffnung des warzenfortsatzes. Arch Ohrenheilkd 1873;7:157. [2] Zaufal E. Technik der Trepanationdes Proc. Mastoid. Nach Kuster‘‘schen Grundsatzen. Arch Ohrenheilkd 1893;30:291. [3] Shambaugh GE, Glasscck ME. Surgery of the ear. Philadelphia: WB Saunders; 1980. [4] Wullstein HL. Tympanoplasty and its results. Arch Ohren Nasen Kehlkopfheilkd 1958;171: 84–90. [5] House WF. Middle cranial fossa approach to the petrous pyramid. Report of 50 cases. Arch Otol 1963;78:460–9. [6] Haynes DS. Surgery for chronic ear disease. Ear Nose Throat J 2001;80:8–11. [7] Jackson CG, Touma B. A Surgical solution for the difficult chronic ear. Am J Otol 1996;17: 7–14. [8] Sheehy JL. Mastoidectomy: the intact canal wall procedure. In: Otologic surgery. Chapter 18. 212–24. [9] Dornhoffer J. Retrograde mastoidectomy with canal wall reconstruction: a follow-up report. Otol Neurotol 2004;25:653–60. [10] Dodson EE, Lambert PR. Intact canal wall matoidectomy with tympanoplasty for cholesteatoma in children. Laryngoscope 1998;108(7):977–83. [11] Haynes DS. Perioperative antibiotics in chronic suppurative otitis media. Ear Nose Throat J 2002;81(1):13–5. [12] Haynes DS, Vos JD, Labadie RF. Acellular allorgraft dermal matrix for tympanoplasty. Curr Opin Otol Head Neck Surg 2005;13(5):283–6. [13] Kim HH, Wilson DF. Titanium mesh for functional reconstruction of the mastoid cortex after mastoidectomy. Otol Neurotol 2006;27(1):33–6. [14] Gantz BJ, Hansen M. Canal wall reconstruction tympanomatoidectomy with mastoid obliteration. Laryngoscope 2005;115:1734–40. [15] Palva T, Ramsay H. Treatment of labyrinthine fistula. Arch Otolaryngol Head Neck Surg 1989;115(7):804–6. [16] Glasscock ME, Poe D. Surgical management of cholesteatoma in an only hearing ear. Otol Head Neck Surg 1990;102:246–50. [17] Lambert P. Mastoidectomy. In: Cummings otolaryngology head and neck surgery. 4th edition. 2005. p. 3075–86. [18] Brackman DE. Tympanoplasty with mastoidectomy: canal wall up procedures. Am J Otol 1993;14:380. [19] Vrabec JT. Delayed facial palsy after tympanomastoid surgery. Am J Otol 1999;20(1):26–30. [20] Jackson CG. Antimicrobial prophylaxis in ear surgery. Laryngoscope. 1988 Oct;98(10): 1116–23.