yi-tsen, lin. introduction pathophysiology pathogens clinical manifestations laboratory studies...
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Yi-Tsen, Lin
IntroductionPathophysiologyPathogensClinical manifestationsLaboratory studies ImagingMedical treatmentSurgical treatmentPrognosis
1959, Meltzer and Keleman: Bacillus pyocyaneus osteomyelitis of
temporal bone in a diabetic patient
1968, Chandler: Malignant otitis externa
Skull base osteomyelitis
Malignant otitis externa
Chronic otitis media
Osteoradionecrosis
Soft tissue infection of the ear canal Spread via the fissures of Santorini and the
tympanomastoid suture Via venous channels and fascial planes within
the temporal bone Along the middle and posterior fossa surfaces Reaching the petrous apex (Gradenigo’s
syndrome) May cross midline
The otic capsule exhibits significant resistance.
Spread to skull base and involvement of IX, X, XI cranial nerves (Vernet’s syndrome)
Intracranial invasion: Meningitis Intracranial abscess Septic thrombosis of the sigmoid sinus or
internal jugular vein
Extracranial extension: Prevertebral / parapharyngeal abscess Spread to sympathetic plexus around carotid
sheath
Bacteria Pseudomonas aeruginosa Staphylococcus epidermidis Staphylococcus aureus Klebsiella spp. Proteous spp. Non-tuberculous mycobacteria (NTM)
Fungus Aspergillus fumigatus
Pseudomonas aeruginosa Gram-negative, obligate aerobic bacillus Not normal flora of the ear canal Colonization after significant water
exposure or minor trauma A mucoid layer carrying lytic enzymes
necrotizing vasculitis
Non-tuberculous mycobacteria (NTM) Mycobacterial species other than the M.
tuverculosis complex or M. lerae
Rapidly growing mycobacteria Slowly growing mycobacteria
Diagnosis: ▪ Repeated isolation of the same NTM species ▪ Typical granulomas or presence of mycobacteria
on histopathology
Fungus Less commonly associated with diabetic
patients Immunocompromised patients (e.g. HIV,
hematologic malignancies) History of chronic otitis media
Most common: Aspergillus fumigatus
Diabetic patients Defects in: chemotaxis, phagocytosis,
oxidative burst and killing function of PMNs, and cellular immunity
Neutral pH of the cerumen Diabetic microangiopathy Ischemia
P. aeruginosa infections
Patients with HIV infections Decreased numbers of CD4 T cells Impaired chemotaxis and neutrophil
degranulation Blunted humoral immue response
P. aeruginosa infections (CD4 <100/mm3) Invasive Aspergillus infections (CD4
<50/mm3)
After water exposure or trauma “Deep” otalgia
Severe, unremitting, and throbbing pain May accompanying headache and TMJ pain Worse at night Refractory to analgesics
Fever is uncommon.
Diabetic or immunocompromised patients
A tender and swollen external auditory canal
A granulomatous polyp in the floor of the external auditory canal at the bony-cartilaginous junction
Cranial nerve palsy (Most common: CN7)
Petrous apicitis1907, Gradenigo:
Triad: Constant otorrhea, headache, diplopia
Diagnostic Criteria Suppurative otitis media Pain in the distribution of the trigeminal
nerve Abducens nerve palsy
Jugular foramen syndromeParalysis of the glossopharyngeal,
vagus, and accessory cranial nervesCauses:
Skull bass osteomyelitis Trauma VZV infection Cholesteatoma Giant cell arteritis
Culture
Tissue biopsy
Laboratory studies
Image studies
LeukocytosisErythrocyte sedimentation rate (ESR)
Evaluation for diabetes
HRCT of temporal bone
MRI
Technetium-99 SPECT
Gallium-67 Scan
Skull base bone destruction More than 30% of affected bone
demineralization to appear eroded on CT Abscess formation
Not an appropriate exam to evaluate response Remineralizaiton of afflicted bone may
never occur despite resolution of the infection.
Erosion of the tympanic plate along the posterior margin of the
mandibular fossa
Erosion of the tympanic plate along the posterior margin of the
mandibular fossa
Identifying soft tissue changesHigh signal intensities on T2-WIsDural enhancement Involvement of the medullary space
of bone
Change in MRI do not resolve with disease.
Trigeminal ganglion in Meckel cave
Trigeminal ganglion in Meckel cave
CN6 Abducens Nerve
CN6 Abducens Nerve
Jugular ForamenJugular Foramen
Hypoglossal canalHypoglossal canal
Petrous apex (small arrow)Constriction of the carotid artery (large arrow)
Petrous apex (small arrow)Constriction of the carotid artery (large arrow)
Invovement of infratemporal fossa
Invovement of infratemporal fossa
Invovement of paraspinal space
Invovement of paraspinal space
Areas of increased osteoblastic activity Infection, trauma, neoplasm, and
postoperative conditions
Three phase bone scan Immediately after injection (blood flow phase) 15 minutes after injection (blood pool phase) 4 hours after injection (osseous phase)
Osteomyelitis: intense uptake in all 3 phases
Earlier diagnosis of osteomyelitis Bone demineralization need not be
present.
The 99Tc bone scan remains positive for several months after clinical resolution. Bone repair continues for a prolonged
period after injury.
Grade I: Mild uptakeGrade II: Focal mastoid/temporal bone uptake not reaching midlineGrade III: Petrous temporal bone uptake reaching midlineGrade IV: Uptake crossing midline to involve the contralateral side
Grade I: Mild uptakeGrade II: Focal mastoid/temporal bone uptake not reaching midlineGrade III: Petrous temporal bone uptake reaching midlineGrade IV: Uptake crossing midline to involve the contralateral side
Areas of active inflammation (infection) by binding to acute phase reactants
It should be repeated every 4 weeks to monitor antibiotic response until it is normal.
It returns to normal sooner once the infection is resolved.
Antipseudomonal antibiotics Ceftazidime Ciprofloxacin
Ticarcillin or piperacillin 3rd or 4th cephalosporin (e.g. cefepime) Carbapenem (e.g. imipenem)
Ceftazidime A third generation cephalosporin Bactericidal activity against P.
aeruginosa Monotherapy Combined with an aminoglycoside to:
▪ Broaden the spectrum▪ Reduce resistance▪ Potentially improve treatment result
Ciprofloxacin Strong bone penetration Effectiveness against Pseudomonas Rapid accumulation in tissue with oral
administration A mild side effect profile Rising resistance? Magnesium salts reduces GI absorption. Concurrent administration with theophylline
can lead to toxicity.
Treatment time At least 4 to 8 weeks A change to oral antibiotic after an initial
2 week course of IV combined therapy in patients with early disease
The previous treatment of these patients with topical or oral antibiotics often leads to negative cultures of the external auditory canal.
Bacterial identification and sensitivities ?
Djalilian HR et al. 2006
A retrospective study 8 consecutive patients over a 2-year
period Median age: 54 years (42-84 yr) Comorbidity: all pts with DM Treatment
Topical polymyxin, neomycin, and hydrocortisone
Oral ciprofloxacin (750mg two times per day) Intravenous ceftazidime (2g every 12 hours)
▪ Peripheral intravenous central catheter (PICC)
NTM infection (combination therapy) Antibiotics
▪ Duration of medical treatment: average 7 months
▪ Until a disease free period of 4-6 months Surgical debulking or clearance of
disease
Petrini B 2008
BiopsyDebridement of granulation tissueDecompression of cranial nerves
The first-line treatment of osteomyelitis in areas other than the cranial base includes aggressive debridement of devitalized tissue.
MastoidectomyPetrosectomy
Infracochlear approach Transmastoid infralabyrinthine approach Middle fossa approach Translabyrinthine approach Transotic appoach
Infracochlear approach
Infracochlear approach
Transmastoid infralabyrinthine approachTransmastoid infralabyrinthine approach
Middle fossa approach
Middle fossa approach
Translabyrinthine approach
Translabyrinthine approach
Transotic approachTransotic approach
Removal of the bone circumferentially around the sound conduction/transduction pathway
Intraoperative facial and trigeminal nerve monitoring
Visosky AMB et al. 2006
A curved incision begins at 0.2 cm posterior and inferior to the mastoid tips, and ends at the zygomatic zoot in the preauricular crease.
The skin and temporoparietal fascia is reflected anteriorly and inferiorly.
The temproralis muscle is reflected inferiorly, and the anterior edge is left attached to the periosteum.
A mastoidectomy is performed along with an extended facial recess approach.
The facial nerve is skeletonized.
The bone overlying the posterior and middle fossa dura and the sigmoid sinus is removed.
The semicircular canals are skeletonized.
The integrity of the external auditory canal is preserved.
A craniotome is used to turn a bone flap from the sinodural angle to the zoot of zygoma.
The petrous apex is exposed by elevating the middle fossa dura. The internal auditory canal and the semicircular canals are skeletonized.
The anterior 1/3 of the temporalis muscle is left in place.
The middle 1/3 is inserted into the petrous apex defect.
The posterior 1/3 is used to fill the mastoid and the jugular fossa.
Pts
Age
Sex
Diagnosis Operation
1 8 MGradenigo syndromeTolosa-Hunt Syndrome
Modified circumferential petrosectomy and complete mastoidectomy
2 14 M Gradenigo syndromeModified circumferential petrosectomy
3 66 FAcute mastoiditis with petrous apicitisFacial palsy
Modified circumferential petrosectomyMastoidectomy (zygomatic and supralabyrinthine air cells)
4 84 MCranial base osteomyelitisFacial palsy
Modified circumferential petrosectomy
5 56 FCranial base osteomyelitis
Circumferential petrosectomy
Culture-directed antibiotic therapy as the first-line treatment.
For recalcitrant disease, the circumferential petrosectomy provides the capability to debride the necrotic bone and the inflammatory tissue with a low risk of morbidity.
This procedure can be tailored to the extent of the patient’s disease.
Visosky AMB et al. 2006
Success in the treatment of osteomyelitis elsewhere in the body
Oxidative killing by leukocytes of aerobic bacteria (P. aeruginosa)
In otogenic skull base osteomyelitis, it did not influence disease-specific survival.
Grade I: Mild uptakeGrade II: Focal mastoid/temporal bone uptake not reaching midlineGrade III: Petrous temporal bone uptake reaching midlineGrade IV: Uptake crossing midline to involve the contralateral side
Poor prognostic factors: Fungal / mixed infection Immunocompromised Cranial nerve palsy Intracranial extension
1. Lee S et al., Otogenic cranial base osteomyelitis: a proposed prognosis-based system for disease classification. Otol Neurotol 2008; 29: 666-272
2. Sreepada GS et al., Skull base osteomyelitis secondary to malignant otitis externa. Curr Opin Otolaryngol Head Neck Surg 2003; 11: 316-323
3. Djalilian HR et al., Treatment of culture-negative skull base osteomyelitis. Otol Neurotol 2006; 27: 250-255
4. Merchant S et al., Osteomyelitis of the temporal bone and skull base in diabetes resulting from otitis media. Skull Base Surg 1992; 2(4): 207-212
5. Petrini B, Non-tuberculous mycobacterial infections. Scad J Infect Dis 2006; 38: 246-255
6. Horwich P, Approach to imaging modalities in the setting of suspected osteomyelitis. Uptodate 2008
7. Coker NJ et al, Atlas of otologic surgery. 1st Ed. Saunders8. Visosky AMB et al., Circumferential petrosectomy for petrous apicitis and
cranial base osteomyelitis. Otol Neurotol 2006; 27: 1003-1013
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