neurosurgical

1. JUGULAR FORAMEN ANATOMY
AND APPROACHES
Dr Dikpal

2. Anatomy
• located at the posterolateral skull base
• long axis obliquely directed in the
posterolateral to anteromedial
• formed by the petrous temporal bone
anterolaterally and by the jugular process of
the condylar part of the occipital bone
posteromedially

8. • The jugular foramen is traditionally divided
into a large posterolateral compartment (pars
venosa) and a smaller anteromedial
compartment (pars nervosa)
• three compartments: two venous
compartments and one neural intrajugular
compartment in between

9. • The venous compartments include a large
posterolateral sigmoid part and a small
anteromedial petrosal part.
• At the junction : two bony prominences
(intrajugular processes), arising from the
temporal and occipital bones: intrajugular
septum

10. • The dura over the intrajugular septum has two
characteristic perforations:
• (1) The glossopharyngeal meatus for the IX
nerve and
• (2) A larger vagal meatus for X and XI nerves

13. • The inferior petrosal sinus (IPS) joins the
jugular bulb in 90%, passing between the IX
nerve superolaterally and the X and XI nerves
inferomedially
• In 10% it drains directly into the internal
jugular vein

14. Condylar emissary vein
• The occipital condyle (OC) contains a condylar
emissary vein in 70% of cases.
• This posterior condylar vein enters the jugular
foramen at its posteromedial part and serves
as a landmark to the foramen for the posterior
approaches
• The hypoglossal canal contains a venous
plexus, called anterior condylar vein in
addition to the XII nerve

15. Relations at skull base

18. Classification of JF lesions
• Fisch’s and Glasscock and Jacobson’s
classification for glomus jugular tumours
• Keye’s and Franklin’s classification for
schwannoma.
• The one proposed by Bertalanffy and Ulrich is
applicable to any type of lesion

19. Bertalanffy and Ulrich classification

20. difficulties in exposing
• its deep location
• the carotid artery anteriorly,
• the facial nerve laterally,
• the hypoglossal nerve medially,
• The vertebral artery inferiorly,

21. Surgical approaches
• Posterior
• Lateral
• Anterior

22. Posterior approach
• Sub occipital (SO) retrosigmoid
• SO transcondylar
• SO supracondylar

23. SO retrosigmoid
• One component of more extensive exposure
• Main indication (intradural)
type A schwannoma, acoustic schwannoma
epidermoid cyst
• Intracranial part of JF exposed by dissecting
arachnoid around 9,10,11
• Disadv: extradural and intrajugular

24. Suboccipital Transcondylar
• More extended lateral and inferior exposure
Bony resection includes
• Post and medial occipital condyle
• Jugular tubercle to expose hypoglossal canal
• Jugular foramen dorsally and inferiorly (post
emissary vein landmark)
• Risk : Injury (VA, CN)

25. Supracondylar app
• Small lesion limited to hypoglossal canal and
medial rim of JF
• SOC extended down to supracondylar fossa
• OC and FM preserved
• Jugular tubercle drilled extradurally
• Disadv : radical resection not possible

26. Anterolateral Approach
• Postauricular transtemporal
• Preauricular subtemporal – infratemporal
approach
• The skin incision: pre- or retroauricular, and
starts above the level of the pinna
• extends in a curvilinear fashion inferiorly into
the neck superficial to the SCM

28. Postauricular transtemporal
• Key component : mastoidectomy and neck
dissection
• Mastoidectomy : involve the intralabyrinthine
region with exposure of the sigmoid sinus,
jugular bulb, and mastoid portion of the facial
nerve
• Facial nerve mobilsed
• Rectus capitis lateralis ms detached
• Hearing does not sacrificed

29. Preauricular subtemporal –
infratemporal approach
• Preauricular incision across zygoma
• FT craniotomy
• Mobilisation of TM joint
• Middle cranial fossa removed , until carotid canal is
reached
• eustachian tube and tensor tympani muscle sacrificed
• removal styloid process allows anterior mobilization of
the internal carotid artery and access to the clivus.
• Drilling of Kawase's triangle gains access to the
posterior cranial fossa.

30. Fisch description
• Type A allows access to the temporal bone in
its infralabyrinthine and apical compartments
• Postauricular incision
• EAC transected
• Neck dissection : identification of CN , vessels
• Radical mastoidectomy and subtotal
petrosectomy
• Facial N anterior transposition

31. • Both middle and posterior cranial fossa dura in
front (Trautmann's triangle) and behind of the
sigmoid sinus are exposed.
• The petrous internal carotid artery is identified
and the eustachian tube is obliterated at its bony
isthmus.
• The mandibular condyle is resected, and the
temporal root of the zygoma and lateral orbital
rim are removed for additional exposure

33. Lateral approaches
• Juxtacondylar
• Lateral skull base

34. Juxtacondylar app
• Extradural, confined to jugular F
• Incision : superior nuchal line to medial border
of SCM below mastoid
• Transverse process of atlas removed and VA
transposed
• PL aspect of OA and AA joint exposed
• Post belly of digastric resected and occipital
artery ligated

35. • Partial mastoidectomy done distal SS exposed
• Post inf wall of jugular bulb drilled to expose
JF
• Adv : wide exposure of post inf JF without
petrous drilling : preserves hearing
• Extradural : no csf leak
• Risk : VA injury , venous bleed

36. Lateral Skull base
• Conserving Otic capsule
infratemporal fossa type A
Petro Occipital Trans Sigmoid (POTS)
• Sacrificing Otic Capsule
Translabyrinthine
transcochlear

37. Infratemporal fossa type A
• Incision : post auricular extending superiorly
to temporal region
• Inferiorly along ant border of SCM

39. • EAC closed
• VII CN exposed by neck dissection
• Lower CN , ICA, ECA, IJV exposed
• SCM and Digastric divided
• ECA ligated beyond Lingual br
• TM , malleus incus removed
• Radical mastoidectomy done

40. • VII CN freed from geniculate ganglion to
stylomastoid foramen and transposed
anteriorly
• Mandibular condyle is resected
• SS is packed or ligated
• Lateral wall of SS is opened to bulb and IPS
and entry of condylar vein packed
• ADV : wide exposure of anterior of JF till
petrous apex

41. Petro Occipital Trans Sigmoid
• Infralabyrinthine lateral skull base
• Indicated for :
• lower cranial nerve schwannomas with
intracranial extensions
• meningioma of the jugular bulb small
petroclival meningiomas lying anterio to the
internal auditory canal (IAC) with preserved
hearing.

42. • Technique: c shaped post auricular incision
• U shaped musculoperiosteal flap raised
• SCM retracted post
• IJV ant to lateral process of atlas identified &
ligated
• Radical mastoidectomy
• VII CN and JB identified

43. • Bone over SS and JB and posterior fossa dura
in front of the SS are removed
• suboccipital craniotomy
• The infralabyrinthine petrous bone is drilled
away taking care not to injure the posterior
semicircular canal or VII nerve.
• The occipital condyle is partially drilled up to
the hypoglossal canal

44. • SS is then opened and packed distally and
proximally
• A horizontal dural incision is made starting
posterior to the SS, coursing anteriorly traversing
the medial wall of the SS
• The removal of the lateral wall of the JB and, if
necessary, its medial wall, fully exposes the
intracranial part of IX−XI nerves.
• The dura over the drilled part of the OC is
excised exposing the hypoglossal canal

45. • ADV: hearing preserved
• Disadv: limited control over ICA , so
involovemet of ICA is contraindication