TITLE: Pediatric Mastoidectomy
SOURCE: Grand Rounds Presentation, The
Department of Otolaryn=
gology
DATE: May 28, 2010
RESIDENT PHYSICIAN:
FACULTY PHYSICIAN:
DISCUSSANT:
DISCUSSANT: Francis B. Quinn, Jr., MD
SERIES EDITOR: Francis B. Quinn, Jr., MD
ARCHIVIST: Melinda Stoner Quinn, MSICS
"This material was prepared by resident physicians in par=
tial
fulfillment of educational requirements established for the Postgraduate
Training Program of the UTMB Department of Otolaryngology/Head and Neck Sur=
gery
and was not intended for clinical use in its present form. It was prepared =
for
the purpose of stimulating group discussion in a conference setting. No
warranties, either express or implied, are made with respect to its accurac=
y,
completeness, or timeliness. The material does not necessarily reflect the
current or past opinions of members of the UTMB faculty and should not be u=
sed
for purposes of diagnosis or treatment without consulting appropriate
literature sources and informed professional opinion."
Introduction
Pediatric mastoid disease is potentially life threatening disease that has seen a decline since the introduction of antibiotics. However, it is s= till present today, and understanding of the surgical treatment of this disease = is vital for every otolaryngologist.
History
The first mastoidectomy was credited to Louis Pe= tit, who used a trochar to drill into the mastoid. Trephination, the drilling of hole= s into the skull, has been done since prehistoric time and there are many fossils which show holes in skulls.
Schwartze, however, was the first to describe the mastoidectomy with instructions and detailed drawings on how to perform the surgery. What he described wa= s the cortical mastoidectomy, which was the main technique used in the preantibio= tic time. He used the chisel and = gouge, which was used extensively until the 1950’s, when more modern techniq= ues were developed.
In 1910, Dr. Bondy described the modified mastoidectomy for the first time. Then in 1922 Lempert introduced the electrically driven drills in ear surgery. Dr. Wullstein introd= uced the operating microscope in 1930, which paved the way for modern mastoidectomies.
Dr. House revolutionized mastoidectomy by introd= uction of the suction irrigations system and inventing the canal wall up mastoid, which is popular today.
Anatomy
The temporal bone is divided into four parts, the petrous, the tympanic, the mastoid and the squamous portion.
The mastoid region is where mastoidectomies are performed. The transmastoid s= urgery provides access to the facial nerve, the carotid, the jugular, and the inte= rnal auditory canal.
When comparing and adult vs. child temporal bone, there are two main differences. First, the infant has an underdeveloped mastoid that is highly aerated. Second, the tympanic ring is also underdeveloped.
Indications
The most common indications for pediatric mastoid surgery are cholesteatoma, ac= ute or chronic mastoiditis and the coexistence of the two diseases.
Less common are temporal bone neoplasm, fracture= s, CSF leak, and facial nerve decompression.
Classical procedures
The classical procedures are:
· Canal wall up:
o
o
· Canal Wall Down:
o
o
· And combination procedures: tympanomastoidectomy, neurotologic approaches.
Simple Mastoidectomy
This is indicated for the acute surgical Mastoid= itis, called “coalescent mastoid”, which is when a collection of fluid forms in the mastoid which obliterates the normal air cells.
Therefore, this is used for medical management failure, Cholesteatoma that extend to the air cells, cochlear implants and other non common procedures.
Surgical preparation
A preoperative audiometry is a must. No one should operate on an ear un= less the status of the hearing is known and recorded. This not only protects the physici= an from accusations of iatrogenic hearing loss, but also provides a guide duri= ng surgery on how extensive the surgery need be.
An image study is also essential.
Procedures and Methods
Muscle relaxants should be avoided. Nerve monitoring is useful, especi= ally in revision surgeries, but some authors suggest this is not essential.
The patient should be place in the supine positi= ons, with their head turned away from the affected side. Hair is either shaved or tape out = the surgical field. The microscop= e is balanced at 225-300mm distance.
The post auricular incision is made. In young children, usually less th= an 4 yrs old, the mastoid tip is not well developed. This causes the stylomastoid foram= en to be more superficial, which allowing the facial nerve to be vulnerable to damaged. Therefore, the incis= ion in young children is made more posterior and more superficial.
The cortex is exposed by making a cut through the linea temporalis with a vertical cut, and another incision extended posteri= orly to mastoid tip, in “T” fashion. An elevator can then be used= to elevate the soft tissue off the cortex.&nb= sp;
Retractors can then be used to keep the wound open. At this time, identific= ation of the landmarks is key. One = should identify the linea temporalis, the cribriform area, the spine of Henle, and MacEwen’s triangle. The= MacEwen’s triangle is defined as the posterior border of the EAC, the anterior line of the zygomatic arch, and a line that connects the two. The antrum is located 15mm medial = to this.
Next, one can start with a burr cut along the te= mporal line. In general, a large bur= r is preferred over the smaller ones. The cutting burr is better for cortical bone, and the diamond burr is used for thin bone over the facial nerve, sigmoid, tegmen, etc. Suction irrigations are used to pr= event excessive heat which can damage vital areas, also to remove bone dust from = your field. Saucerization (drillin= g of the edge of the mastoid bowl) is used to provide better exposure. One should now identify the tegmen= as a pink color of bone superiorly, which also has exposed vessels once you are close to the dura. The deepes= t part of the surgery is the antrum. Once the epitypanum, zygomtic cells, body of incus and head of the malleus is identified, then your dissection is complete. Cultures are then taken and a typanostomy tube can be place if needed.
Complete mastoidectomy
This is an extension of the simple mastoidectomy= , with more access to the attic, labyrinth, endolyphatic sac and facial nerve. A complete mastoidectomy can be described as a simple mastoidectomy with a facial recess approach. The canal wall remains up for this operation.
Indications are the same for the simple, but wit= h greater access to the mastoid cavity and facial nerve, which is more common in chol= esteatoma surgery.
First, the complete mastoidectomy starts with a = simple mastoidectomy. The EAC is fir= st thinned laterally to medially. The medial portion will be the facial recess.&= nbsp; This is bound laterally by the chorda tympani, medially by the facial nerve and superiorly by the fossa incus.&n= bsp;
Once access to the facial nerve recess is achiev= ed, gaining access to the epitypanum may be necessary. Also, the incus may need to be rem= oved if it is eroded. One must be = aware of facial nerve dehiscence, which is up to 50% of temporal bone surgeries.<= span style=3D'mso-spacerun:yes'>
Modified Radical Mastoidectomy
This is more commonly used for cholesteatoma surgery. In this surgery, the= canal wall is taken down, but the tympanic membrane is maintained. Indications for this surgery are t= he same for the previous surgeries, but used when the previous surgeries have failed, such as when irrigation fluid fails to flow from the middle ear to = the mastoid region.
The modified mastoidectomy is started as a compl=
ete
mastoidectomy, but the posterior canal wall is removed. Care is taken to preserve the tymp=
anic
membrane, which is replaced.
The mastoid cavity is enlarged after this surgery, so care must be m=
ade
to saucerize the edges so that the surrounding soft tissue may collapse into
the defect. However, the
mastoid is never grafted or obliterated in children, as with adults. This is because residual disease i=
s more
likely to be present in children, which would be obscured with grafting.
However, removal of the posterior canal wall is = very undesirable in children.
Radical masto=
idectomy
This surgery is the removal of the mastoid cavit= y, the external canal, and the middle ear. This was once performed frequently in the past, but is limited in its usefulness since the use of antibiotics.&n= bsp; As well, the previously described surgeries have replaced the use of= the radical mastoidectomy.
Therefore, the indication is mainly failed surge= ries that need to be more extensive. An uncommon use in children is for better access to the temporal bone for tumo= rs.
The radical mastoidectomy is started as a modifi= ed radical mastoidectomy. Howeve= r, the tympanic membrane, the malleus and the incus are also removed. Next, a meatoplasty is done, which= is the removal of the soft tissue and conchal cartilage.
Complications of mastoidectomy
The peri-operative complications include facial = nerve injury, sensorineural hearing loss, post operative infection, brain herniat= ion, cerebrospinal fluid leakage, and bleeding.
Delayed complications include posterior canal breakdown, pericondritis, mucosalization of the mastoid bowl, and stenosis = of the external canal.
Canal wall up vs. Canal wall down
There is controversy over the use of the canal w= all up vs. the canal wall down. The = canal wall down provides the best exposure to the mastoid which will be the best procedure to eliminate the disease. However, having this done requires periodic cleaning of the mastoid bowl, which is unconformable. In children, this requires general anesthesia. Also, swimming, which is common in children, predisposes open mastoids to infections. Therefore every attempt shou= ld be made to no do a canal wall down in children.
However, in canal wall up surgery, the exposure = is not as well, and therefore residual disease may be present. That is why a second look operatio= n is needed to look for reoccurrence of disease. This is done 6 months after the su= rgery, which is different from the 12 months of adult surgery. If residual disease is found, it i= s then removed if possible, and then a re-exploration surgery is done. Otherwise, the surgery is converte= d to a canal wall down procedure.
Conclusion
It is important to understand the indications, t= he anatomy and different techniques and why they are performed. Each operation should be tailored = to each child. In children, they= have a smaller mastoid tip which predisposes them to facial nerve injury. Every attempt should be made to re= tain the canal wall up. Follow up = and re-exploration is key to prevent and control reoccurrence of the disease.
Discussion
QUESTION: When do you perform a mastoidectomy=
?
REPLY: A mastoidectomy should be done when
coalescence is formed in the mastoid which disrupts the air cells. Otherwise, patient should have IV
antibiotics and a myringotomy with tube placed.
QUESTION: What the difference in terminology
between simple mastoidectomy and complete mastoidectomy?
REPLY: Some authors suggested that the
difference between the simple mastoidectomy and the complete mastoid was th=
at
the complete had the facial nerve recess opened. This difference in terminology may=
have
arisen from the fact that reimbursement coded more for complete mastoidecto=
my.
QUESTION: Facial nerve monitoring?
REPLY: It is now the standard of care to h=
ave
facial nerve monitoring in all cases of mastoidectomy, no matter if it is a
repeat surgery or not.
Discussant's Remarks – Francis B. Quinn, Jr., MD
During my child=
hood
(the 1930's), with many earaches and many myringotomies, I learned that to a
parent, the work "mastoid" brought fear and desperation. The "Mastoid Operation&=
quot;
in those days, often performed with mallet, gouge and curette, was attended=
by
a significant mortality despite the availability of the sulfadiazine
drugs. Looking back on the
literature of those times, one can suspect that the death rate from
complications of otitis media, or, in the parent's perception, from the mas=
toid
operation itself (called in those days, the "simple mastoidectomy"
and later for medicolegal reasons, the "complete mastoidectomy") =
was
often performed too late in the course of the disease, when the infection h=
ad
already spread to the meninges, the sigmoid sinus, the brain parenchyma, the
petrous pyramid or the vestibular labyrinth. .
During my years=
as an
active general otolaryngologist armed with the penicillins, the question wo=
uld
come up of whether or when to perform a complete mastoidectomy on a child w=
ith
particularly severe or protracted purulent otitis media. Lacking the CT scan and the tympan=
ostomy
tube, we relied upon the appearance of the eardrum, a four view temporal bo=
ne
xray and the textbook signs of acute mastoiditis (displacement of the pinna,
postauricular edema and tenderness, sagging of the external canal roof,
unremittant otalgia, fever and malaise.)&n=
bsp;
Radiologic demonstration of coalescence of the mastoid cells was an
absolute indication for surgery.
Today's present=
ation
while complete and illustrative, offers no guidance on whether and/or when =
to
perform the complete mastoidectomy operation in a case of unresponsive acute
purulent otitis media and mastoiditis.&nbs=
p;
By coincidence, in today's xray conference, we saw CT images of a
mastoid bone with extensive coalescence of the pneumatic septae accompanied=
by
indisputable evidence of destruction of the overlying mastoid cortex and a =
soft
tissue abcess at the mastoid tip.
The resident informed us that in this case the treatment was limited=
to
antibiotic drugs and myringotomy with insertion of tympanostomy tube. The child recovered, but no follow=
-up CT
scan was available. If this is
representative of the current view, is there a place for the complete
mastoidectomy at all in today's practice?&=
nbsp;
Or have we forgotten the "silent mastoiditis" of Francis
Lederer and George Shambaugh, Jr., wherein the latent mastoid infection fin=
ally
announced itself in the form of meningitis, epidural abscess, brain abscess,
and the like?
I will offer yo= u an old Irish proverb, "The wisdom= of winter is madness in May" and will turn to Dr. Mukerji and Dr. Pine for their experience in this now rare but potentially devastating disease.<= o:p>
Discussant's Remarks: Shraddha S. Mukerji, MD
The indications=
for
mastoidectomies in the pediatric population are similar to those in adults.=
Due to differences in anatomy espe=
cially
in relation to the underdevelopment of the mastoid and tympanic part of the
temporal bone, the facial nerve is much superficial in children younger tha=
n 4
years of age as compared to adults. One has to be careful while making the
post-auricular incision.
Choice of appro=
ach
depends upon extent of disease, presence of intracranial complications,
parental choice and reliability of follow-up.
The most import=
ant
indication for simple mastoidectomy is acute coalescent mastoiditis with or
without subperiosteal abscess formation.
Modified Radical
Mastoidectomy is performed for cholesteatoma which have recurred despite a
formal Canal wall up mastoidectomy, or in the presence of a canal wall
cholesteatoma. Every attempt =
needs
to be made to decrease the size of the cavity since pediatric mastoids are =
well
pneumatized and cholesteatomas tend to aggressive and extensive.
References
Rosenfeld RM, Moura= RL, Bluestone CD. Predictors of residual-recurrent cholesteatoma in children. A= rch Otolaryngol Head Neck Surg 1992;118:384–91
Bluestone CD. Acute and chronic mastoiditis and
chronic suppurative otitis media. In:
Bailey BJ, et al, eds. Head and Neck Su=
rgery
- Otolaryngology. 4nd ed.
= Antonelli PJ, Dhanani N, Giannoni CM, et al. Impact of resistant pneumococcus on rates of acute mastoiditis. Otolaryngol= Head Neck Surg. Sep 1999;121(3):190-4
Harker LA,
Shambaugh GE, Glasscock ME. Pathology and clinical course of inflammatory diseases of the middle ear. Surgery= of the Ear. 1967;186-220
Kvestad E, Kvaerner= KJ, Mair IW. Acute mastoiditis: predictors for surgery. Int J Pediatr Otorhinolaryngol. Apr 15 2000;52(2):149-55
Shambaugh GE, Glasscock ME: =
;Surgery
of the Ear.
Myers, Eugene N, et al. Operative
Otolaryngology-Head and Neck Surgery.
Cummings CW. Otolaryngology-Head and Ne=
ck
Surgery. 5nd ed.