1. Sternberg's canal also known as lateral craniopharyngeal canal 2. lateral craniopharyngeal canal 3. temporal lobe encephalocele in sphenoid sinus 4. its is as differential diagnosis for Arachnoid Pit and Extensive Sinus Pneumatization as the Cause of Spontaneous Lateral Intra sphenoidal Encephalocele

1. STERNBERG’S CANAL
Dr. Poongkamali J

2. DEFINITON
Sternberg's canal is a lateral craniopharyngeal canal resulting from
incomplete fusion of the lateral greater wings of the sphenoid bone with the
posterior basisphenoid which results in connection between the intracranial
space and sphenoid sinus.
It acts as a weak spot of the skull base, which may lead to develop a
temporal lobe encephalocele protruding into the lateral recess of the
sphenoid sinus (SS).
Described by Maximilian Sternberg in 1888- hence the name

3. EPIDEMIOLOGY
Present in around 4% of the adult population- Maximilian Sternberg’s
anatomical studies
Just a single case of Sternberg’s canal during a serial analysis of
the CT scans of 1000 patients representative of the general adult population-
study by Barañano et al, 2009.
The incidence of congenital cranial meningocele/encephalocele in the general
population is 1 in 35,000 people, with just 10% of those occurring at the skull
base- when compared to this general incidence, the Sternberg’s canal
congenital craniomeningocele is considered a very rare event

4. EMBRYOLOGY OF SPHENOID BONE/ SINUS FORMATION
The sphenoid bone develops from the ossification of several independent cartilaginous precursors:
presphenoid and postsphenoid/basisphenoid centers (body of the sphenoid bone),
orbitosphenoids (lesser wings),
alisphenoids (greater wings).
At the time of birth the ossified presphenoid, lesser wings, basisphenoid, greater wings and pterygoid
processes fuse to build the complex sphenoid bone. Only a weak cartilaginous union remains between greater
wings, presphenoid and basisphenoid which corresponds to the future lateral wall of sphenoid sinus. During
the neonatal period their bony fusion of this cartilaginous union starts anteriorly . If the posterior part fuses
incompletely, a bony gap, the so-called LATERAL CRANIOPHARYNGEAL CANAL (STERNBERG’S CANAL) remains.
This gap is located in the posterior part of the lateral sphenoid sinus wall inferior and lateral to the maxillary
nerve (V2).
In the presence of a lateral recess of the SS, the Sternberg's canal can communicate with the SS after its
pneumatization, acting as a possible site of origin of congenital encephaloceles.
Fusion planes offer resistance to pneumatization, so sphenoidal defects at fusion planes are more likely to be
CONGENITAL THAN ACQUIRED.

5. EMBRYOLOGY OF SPHENOID
BONE/ SINUS FORMATION
The sphenoid bone develops from the ossification of
several independent cartilaginous precursors:
presphenoid and postsphenoid/basisphenoid centers
(body of the sphenoid bone),
orbitosphenoids (lesser wings),
alisphenoids (greater wings).
At the time of birth the ossified presphenoid, lesser
wings, basisphenoid, greater wings and pterygoid
processes fuse to build the complex sphenoid bone.
Only a weak cartilaginous union remains between
greater wings, presphenoid and basisphenoid which
corresponds to the future lateral wall of sphenoid
sinus.

6. SPHENOID BONE/SINUS NORMAL RADIOLOGY
OC- Optic canal,FR- Foramen rotundum, SpS- Sphenoid sinus, VC- Vividian canal,PtP- Pterygoid plate, SER-
Sphenoethmoidal recess

7. STERBBERG’S CANAL & LATERAL
CARNIOMENINGOCELE
During the neonatal period their bony fusion of
this cartilaginous union starts anteriorly . If the
posterior part fuses incompletely, a bony gap,
the so-called LATERAL CRANIOPHARYNGEAL
CANAL (STERNBERG’S CANAL) remains.
This gap is located in the posterior part of the
lateral sphenoid sinus wall inferior and lateral to
the maxillary nerve (V2).
In the presence of a lateral recess of the SS, the
Sternberg's canal can communicate with the SS
after its pneumatization, acting as a possible
site of origin of congenital encephaloceles.
Fusion planes offer resistance to
pneumatization, so sphenoidal defects at fusion
planes are more likely to be CONGENITAL THAN
ACQUIRED.

8. STERNBERG’S CANAL & LATERAL CARINOMENINGOCELE RADIOLOGY
CT PNS showing homogenous soft tissue shadow in the
left sphenoid sinus. The arrow showing the area of the
Sternberg’s canal.(left most)
MRI Cisternography pictures showing defect in the left side of
the sphenoid sinus with hernia ion of small portion of the left
temporal lobe with dura & CSF.
Pre-operative imaging. CT scan (left panel) showing
communication between left middle cranial fossa and lateral
pterygoid recess of sphenoidal sinus. Meningocele
herniating through persistent lateral craniopharyngeal canal
as seen on T2-weighted MRI (right panel).

9. CLINICAL FEATURES & PRESENTATION
CSF rhinorrhea
•Starting during adulthood- enhancing
the importance of pneumatization of
the SS in the pathogenesis.
•Most common
•generally intermittent ,not
voluminous.
•Exact proportion of symptomatic
cases of Sternberg’s canal
carniomeningocele is not known
Other signs and symptoms & features
of complications of CSF leak, SOL.
•chronic headache, seizures and
vertigo.
•Persistent postnasal drip
•Features of meningitis- neck
stiffness, vision changes, weakness,
numbness, paresthesia, convulsions,
cognitive changes, fevers, chills, or
night sweats.
Points to remember
• Congenital basal skull deformities
like Sternberg’s canal are not the
most prevalent cause of CSF
rhinorrhea. The presentation is
more commonly due to traumatic
or iatrogenic causes. It is crucial
to identify a history of head
trauma or prior skull base surgery
in the patient, as these are the
most common causes of such
defects.
•WHY IT IS IMPORTANT TO
DIFFERENTIATE
IATROGENIC/TRAUMATIC CAUSES?

10. MANAGEMENT
• Including co- morbidities(HTN/DM/Obesity)
HISTORY
EXAMINATION
• Diagnostic
• Pre-operativeLAB INVESTIGATIONS
• CT -good bone detail and identifies the site of the skull base defect.
• CT cisternography consists of injecting intrathecal water-soluble contrast
medium before the CT scan and then visualizing it at the level of the dural and
skull base defect
• Intermittent or inactive CSF leaks-associated with a high incidence of false-
negative results and MR imaging may be a better choice in those patients
• MR images give better information about the soft tissues like the
encephalocele itself
IMAGING
• A/R, DNE, Vision, Cranial nerve ,muscle power

11. TREATMENT
CSF leaks secondary to trauma or skull base surgery may close on their own, and conservative management is
recommended initially.
Conservative management is also recommended for asymptomatic Sternberg’s canals discovered incidentally,
with close monitoring for CSF leakage.
In contrast, asymptomatic Sternberg’s canal with active CSF leaking may require surgical treatment in
apprehension of the risks posed by CSF leakage, which include meningitis, intracranial hypotension, brain
abscesses, and seizures.
• Hence, repair of intrasphenoidal encephaloceles has two main objectives:
prevention of CSF leak and to avoid central nervous system infection.

12. SURGERY
ADVANTAGES/DISADVANTAGES OF VARIOUS TECHNIQUES:
ENDOSCOPIC APROACH
Advantage – less invasive
Disadvantage-
Larger basal sphenoidal opening required in case of laterally place defect- results
increased risk and severity of endoscope-related rhinological complications such
as epistaxis, hyposmia, excessive conchal loss, and dry nasopharynx.
Endoscopic procedure involves a more contaminated route of approach when
compared to Transcranial approach.
OPEN INTRACRANIAL APPROACH
Advantage-
full visualization
Complete reduction of the meningocele, and effective repair.
Sterile route of approach
Disadvantages-
Need to expose the temporal lobe laterally, which is associated with post-
operative seizures as well as a higher incidence of stroke related to Vein of Labbé
injury.
Open craniotomy also incurs the risks of infection, bleeding, and CSF leak
postoperatively.
NO STANDERED GUIDELINES FOR SLECTION OF ROUTE AND METHOD OD
SURGICAL APPROACH- DEPENDS ON THE COMBINED DECISION OF
NEUROSURGEON AND OTORHINOLARYNGOLOGIST.
APPROACHES-Trans-nasal, Trans-septal, Tans-
pterygoid sphenoidal access or transcranial
Autologous fat graft can be used to seal the
bony defect. Various other materials, both
synthetic and autologous, are also been used
but fat grafts have been the most successful
Autologous fascia lata from the patient’s
thigh can used to cover the fat graft and as a
duroplasty patch to repair the temporal lobe
dura following meningocele excision.
Bony or titanium mesh scaffolding may be
required in cases with larger defects.

13. VARIANTS
Arachnoid Pit and Extensive Sinus Pneumatization as the Cause of Spontaneous Lateral Intra
sphenoidal Encephalocele
• Arachnoid pits are smooth, lobulated bony defects that are related to aberrant arachnoid granulations. CSF
pulsation and its pressure also play an important role in the creation of these defects. This role of the CSF is
evident from the pattern of the bony remodeling, with outward concave orientation of adjacent bones.
• CSF pressures and the hydrostatic pulsative forces may lead to the development of pit holes on the middle
fossa at the sites of arachnoid villi with herniation of dura/arachnoid or brain tissue.[6] If such defects are
located over the underlying lateral extension of the sphenoid sinus, encephalocele can develop and lead to
CSF leakage into the sinus. NOT SIMILAR TO LATERAL SPHENOIDAL CRANIOMENINGOCELE DUE
TO STERNBERG’S CANAL(ACQUIRED).

14. THANK YOU