Download Lesions of and Surgical Approaches to the Petrous Apex

Lesions of and
Surgical Approaches
to the Petrous Apex
2.12.14 - Galloway - Denneny
O Truncated pyramid
O Medial to the inner
ear labyrinth
O Can be bisected by
coronal plane
through the IAC into
the anterior and
posterior petrous
apex
Pneumatization
O
Sclerotic
O
O
Diploic
O
O
33% of patients
Anterior petrous apex
O
O
Middle ear
Squamomastoid
Petrous Apex
Perilabyrinthine
Accessory air cells
Posterior petrous apex
O
O
Air filled
5 general areas of pneumatization in the
adult temporal bone
O
O
O
O
O
O
Marrow filled
Pneumatic
O
O
Solid bone
10% of patients
Not always symmetric
O
4-7% of pneuatization is asymmetrical
Pneumatization
O Supralabyrinthi
ne
O Retrolabyrinthin
e
O Infralabyrinthine
O Anterior
labyrinthine
The Petrous Apex
O How do we find these
lesions?
O Are not amenable to
direct clinical evaluation
O Imaging
O Symptoms which correlate
with anatomic proximity to
structures
O What are these lesions?
O What do we do with them?
Differential to Lesions of the
Petrous Apex
O
O
O
O
O
O
O
O
O
O
O
O
O
Asymmetric marrow
Petrous apex effusion
Petrous apex cephalocele
Petrous apicitis
Cholesterol granuloma
Cholesteatoma
Mucocele
Skull base osteomyelitis
Meningioma
Chordoma
Malignancies – metastasis, myeloma, chondrosarcoma
Langerhans cell histiocytosis
Endolymphatic sac tumor
Asymmetric Marrow
O
Usually an incidental finding obtained for non-otologic complaints
O
Variable pneumatization of the petrous apex
O
O
4-7% of pneumatized apices are asymmetrical
Marrow space should follow same signal characteristics as orbital fat
on MRI T1 and T2
O
O
 T1 and decrease in intensity with T2
Fat saturation should fully suppress the signal
O
CT should demonstrate a nonexpansile, nonaerated petrous apex
O
No further follow up is indicated
O
This may be misconstrued as a cholesterol granuloma
Asymmetric Marrow
O Leave me alone” lesions of the petrous apex AJNR Am J
Neuroradiol 19:733-738. April 1998.
O
O
1989-1997 23 patients with “leave alone” lesions
Asymmetric marrow or trapped fluid (effusions)
Petrous Apex Effusion
O
Presumed to represent previous otitis media with subsequent
obstruction of connections between middle ear and apical air cells.
O
Opacified air cells should demonstrate a high T2 signal – equivalent to
CSF
O
The T1 signal may vary, depending on the protein content of the fluid
O
O
Low T1  uncomplicated petrous air effusion
Intermediate or high T1 CT scan to exclude an erosive or expansile
lesion
O
O
or possibly early cholesterol granuloma
Lesions most likely to be misconstrued as cholesterol granuloma
Petrous Apex Effusion
Leave me alone” lesions of the petrous apex AJNR Am J Neuroradiol 19:733-738. April 1998.
Petrous Apex Effusion
Leave me alone” lesions of the petrous apex AJNR Am J Neuroradiol 19:733-738. April 1998.
Petrous Apex Effusion
Leave me alone” lesions of the petrous apex AJNR Am J Neuroradiol 19:733-738. April 1998.
Petrous Apex Effusion
Leave me alone” lesions of the petrous apex AJNR Am J Neuroradiol 19:733-738. April 1998.
Petrous Apicitis
O Complication of spread of infection of the
mastoid and middle ear
O In pre-antibiotic era this well known spread of
otitis media with further intracranial
complications
O Guiesseppe Gradenigo described this classic
triad of symptoms associated with petrous
apicitis in 1907
Gradenigo’s Syndrome
O Deep facial pain
O Otitis media
O Ipsilateral
abducens palsy
http://www.thebarrow.org/Education_And_Resources/Barrow_Quarterly/204927
http://www.thebarrow.org/Education_And_Resources/Barrow_Quarterly/204927
Petrous Apicitis
O Current day symptomatology
typically subtle
O Previous mastoid surgery-
complains of persistent
infection and deep facial pain
O Predominant organism
O P. aeruginosa
O Can also be considered central
skull base osteomyelitis
O If recalcitrant to antibiotics will
require surgical drainage
Petrous Apicitis
O On MRI
O T1- hypointense
O T2 – hyperintense
O Enhancing
O On CT
O Aggressive bony destruction
O Consider gallium scan
O Clinical evidence of infection
http://synapse.koreamed.org/DOIx.php?id=10.3342/kjorl-hns.2009.52.3.279&vmode=PUBREADER#!po=16.6667
Petrous Apicitis
Connor. Imaging of the petrous apex: a pictorial review. The British Journal of Radiology, 81 (2008) 427-435.
Cholesterol Granuloma
O Most common primary lesion of the petrous apex
O 60% of all lesions in this area
O May have silent presentation,
O Expansile mass forms within isolated petrous
apex air cells
O Repetitive cycles of hemorrhage and
granulomatous reaction granulomatous reaction
initiated by obstruction of ventilation output
O Brownish liquid with cholesterol crystals
Cholesterol Granuloma
O Imaging
O MRI
O High T1
O High T2
O Non-enhancing
O CT
O Bony moulding
O Pressure
deossification
O Require Surgical
drainage
Connor. Imaging of the petrous apex: a pictorial review. The British Journal of Radiology, 81 (2008) 427-435.
Cholesteatoma
O Same as cholesteatoma elsewhere
O Proliferation of skin – destructive keratinizing
squamous epithelium
O Congenital vs. Acquired (secondary)
O Acquired
O Erosion from the mastoid/middle ear
O Otorrhea, facial nerve palsy, dizziness, hearing loss
O Intracranial complication- meningitis, lateral sinus
thrombosis, brain abscess
Cholesteatoma
O Congenital
O Theories
O Presence of epidermoid cells in middle ear during
fetal development
O Migration of the external meatus ectoderm
O Less frequent than secondary cholesteatoma
O Can develop for long period without symptoms
O Sudden severe symptoms
O i.e. facial nerve palsy (first symptom of congenital
cholesteatoma), deafness
Cholesteatoma
O CT scan
O Bony destruction
O MRI
O T1- low signal
O T2- high intensity
signal
O Non-enhancing
O Requires surgical
excision
Connor. Imaging of the petrous apex: a pictorial review. The British Journal of Radiology, 81 (2008) 427-435.
Cumming’s Otolaryngology Chapter 135.
Connor. Imaging of the petrous apex: a pictorial review. The British Journal of Radiology, 81 (2008) 427-435.
Surgical Approaches to the
Petrous Apex
Julius Lempert
O Father of modern otology
O Jewish immigrant came to NYC in
O
O
O
O
early 1900’s
One of the three pioneers
Glasscock dedicated his Surgery of
the Ear book in the forward.
First to use dental drills in lieu of
chisels in mastoid surgery
First to wear a headlight, instead
of overhead lights
Developed an approach to the
petrous apex via the carotid artery
which basis for modern skull base
surgery
O
Approach through glenoid fossa
http://www.michaeleglasscockiii.com/21/Julius_Lempert.htm
Surgical Approaches
O
Classic approaches to posterior petrous apex
O
O
O
Anterior petrous apex
O
O
O
O
O
O
Infracochlear
Transotic approach
Middle fossa approach
Transcanal approach
Endoscope assisted approach
Image guidance approach – trans-sphenoidal
O
O
O
Transmastoid infralabrynthine approach
Transmastoid translabrynthine approach
Endonasal endoscopic
Retrosigmoid approach
Transpalatinal-transclival
Surgical Approaches
O Things to consider when choosing an
approach
O Serviceable hearing?
O Drainage vs. Excision?
O Where is your access/aircells?
http://www.mayfieldclinic.com/PE-Acoustic.htm#.Uvr9axZ_hUQ
Transmastoid procedures
O Superior access for mass lesions such as
cholesteatomas
O Infralabryinthine approach can salvage hearing
O Complete mastoidectomy with skeletonization of
facial nerve
O Locate infralabyrinthine air cell tract
O Confirm this on preoperative imaging
O Inferior to posterior semicircular canal, superior to
jugular bulb, medial to facial nerve
O Route passes inferior to IAC, through cochlear aqueduct
(plug with bone wax to prevent CSF leak)
O Translabryinthine approach
Transcanal
O Drainage of limited lesions of the anterior
petrous apex
O Elevate wide, superiorly based
tympanomeatal flap, generous anterior and
inferior canalplasty
O Expose petrous carotid
O Drill between cortical bone of the cochlea,
internal carotid artery and follow air cell
tract to anterior petrous apex.
Endonasal Approaches
O Open approaches to the skull base transphenoidally
have been in practice since the 1980’s
O Endoscopic Approaches
O Medial approach
O Medial approach with internal carotid artery
lateralization
O Transptyergoid infrapetrous approach
O Choose your approach based on the proximity to the
ICA, degree of pneumatizaiton of the sphenoid,
medial expansion of lesion, pathology
Endonasal Approach
Utilization of landmarks
Thank you