This document summarizes a seminar presentation on hydrocephalus. It defines hydrocephalus as an increase in CSF volume with ventricular enlargement. It describes the physiology of CSF circulation and different types of hydrocephalus including obstructive, communicating, congenital and acquired. Clinical presentations and investigations are discussed. Treatment options include temporary external ventricular drainage, VP shunt placement, and endoscopic third ventriculostomy. Complications of shunt surgery and new treatment modalities are also summarized.

1. Seminar on
hydrocephalus
Presenter : Dr Biswajit Deka
PGT 2nd year
Deptt of surgery , SMCH

2. Definition
Hydrocephalus refers to an increase in
CSF volume with ventricular enlargement
Fluid accumulation
• Intracerebral (ventricular)
• Extracerebral (subarachnoid spaces &
cisterns)
Incidence : 3-4/1000 births

3. Physiology
•Total CSF volume : 150 ml
•Site : walls of ventricle & choroid
plexus
•Rate : 20 ml / hr (o.33ml/kg/hr)
•Circulation time : 8 hrs

4. Route of CSF flow
Lateral ventricle foramen of
Monro
Third ventricle cerebral
aqueduct
Fourth ventricle foramen of
Megendie & luschka
sub arachnoid space

6. Types
• Congenital & acquired
• Obstructive & communicating
• Acute (d/t tumour) and chronic (NPH)

7. Congenital hydrocephalus
• Stenosis of cerebral aqueduct
• Chiari malformation
• Dandy walker malformation (90%)
• Myelomeningocele
• Bicker’s Adams syndrome (x-linked, 7%)
• Intrauterine infection (toxoplasma, CMV)—
communicating type

8. Acquired hydrocephalus
• Meningitis
• Germinal matrix Haemorrhage or
SAH
• Adjacent tumours
• Iatrogenic : hypervitaminosis A

9. Obstructive hydrocephalus
• Lesions within the ventricle
• Lesions in the ventricular wall
• Lesions distant from ventricular wall
with a mass effect

10. Communicating hydrocephalus
• Post hemorrhagic
• CSF infection
• Raised CSF protein
• Excessive CSF production - choroid
plexus papilloma / carcinoma

14. Early
• Irritability
• Poor feeding
• Difficulty in focussing eye
• Excessive sleepiness
• Rapid increase in head circumference
• Seizures
Clinical presentation

15. Late
• High pressure headache - coughing /
bending forward
• Nausea & vomiting
• Blurred & double vision
• Eye movement abnormality
• Pupil abnormality
• Fundoscopy - papilloedema (absent in
acute phase)

16. Infant
• Tense & bulging fontanelle
• Increase in head circumference
• Bulging scalp veins
• Impaired conscious levels
• Sunsetting sign

20. • Parinaud's syndrome ( dorsal midbrain
syndrome / vertical gaze palsy / sunset
sign )is an inability to move the eyes up
and down.
• Caused by compression of the vertical
gaze center at the rostral interstitial
nucleus of medial longitudinal fasciculus
(riMLF).

22. Risk
• Cerebral herniation
• CVS instability
• Neurological deficit
• Vision - irreversible damage
• Death

23. Investigation
• CT brain - 1st line
• Degree of mass effect
• Potency of basal cisterns
• Spaces surrounding brainstem
• Cannot delineate exact site &
nature of obstruction.
• Assessment of shunt malfunction

24. • Lumber punture -( herniation )
• MRI - anatomy relating to potential
treatment ;eg third ventriculostomy,
aqueductoplasty & newly diagnosed case
• Cranial USG - new born
• ICP monitoring - transducer in brain
substance

26. Intracranial pressure
waveform
•P1 (percussion
wave) -arterial
pulsation
•P2 - brain
compliance
•P3 (dicrotic wave)-
venous pulsation

27. For communicating hydrocephalus
• LP : diagnostic & therapautic
• Deriving an opening pressure
• Assessment of CSF contents
• Drainage :10-30 ml CSF
• Aim : to make opening pressure half

28. Hydrocephalus ex vacuo
• A/k/a compensatory hydrocephalus
• Ventricle enlarge compulsory to overall
shrinking of the brain tissue .
• D/D : NPH
• Seen in -
• Advance age with brain atrophy
• After diffuse HI or stroke
• Neurodegenerative condition

29. Porencephaly
• Porencephalic cyst
• Loss of volume focal brain substance
— collection of CSF in the cavity
• Localised lesion

30. Arrested hydrocephalus
• Ventricles are enlarged
• No significant symptoms
• Do not require surgical Tx
• May develop symptoms during prolong
period or after acute ppt. factors (trauma
, infection) that alters CSF dynamics.

31. • Cause of dementia
• reversible
• Triad : gait disturbance , incontinence ,
cognitive decline
• De novo or previous brain insult (SAH,
HI, meningitis , tumour )
Normal pressure hydrocephalus

32. • Imaging : ventriculomegaly
• CSF pressure at LP : normal
• But , intermittent elevation in pressure
may be involved in etiology

33. • Lumbar infusion testing : insertion
of a fine drain at LP, f/b
measurement of CSF pressure
changes a/w a fluid challenge
administered through this.
• This allows evaluation of the likely
benefit from definitive treatment by
shunt insertion.

34. Idiopathic intracranial hypertension
• Pseudo tumour cerebri
• Benign intracranial hypertension
• Features of raised ICP with underlying
tumour
• Can cause blindness
• Young , over weight , female
• Headache & visual disturbance

35. • Examination :
• papilloedema
• Cranial nerve palsies
• Imaging : unremarkable
• LP : raised opening pressure > 25mm Hg
• Etiology : not well understood
• Diagnosis : is of exclusion

36. Treatment of IIH
• Weight loss
• Stop : OCPs
• Acetazolamide : to reduce CSF
production
• Shunting : to prevent visual loss
• Optic nerve sheath fenestration

37. Treatment of Hydrocephalus
Acute obstructive hydrocephalus - emergency
Hydrocephalic attack : coma & death
Aim : to treat underlying pathology
Temporary ventricular drainage

38. External ventricular drain
• EVD : effective temporary measure
• Inserted to the right of midline, anterior to coronal
suture, so that the catheter tip rests adjacent to the
fomamen of Monro in the lateral ventricle.
• Catheter connected to drain set such that CSF
drains when the ventricular pressure exceeds a
threshold, typically set at 10-20 mm Hg.
• Intrathecal antibiotics may be delivered

39. • Lumbar drains :
alternative means of temporary CSF
diversion , often used to manage CSF
leaks resulting from communicating
hydrocephalus

40. VP shunt
• Comprises insertion of a ventricular catheter into the
frontal or occipital horn of the lateral ventricle , while
a distal catheter is tunnelled subcutaneously to the
abdomen.
• A shunt valve, with an opening pressure that may be
high, medium or low , is inserted at the junction of
these catheters.
• Selection of shunt valve : patient specific

41. • High pressure valve may fail to allow adequate CSF
drainage ,whereas low pressure valve may
overdrain.
• Anti-siphon system incorporated : to prevent
excessive drainage in standing position.
• Programmable valve : offer variable opening
pressure , adjusted magnetically using a device
applied externally over the valve .
• Valve system will also incorporate a CSF reservoir ,
which allows for percutaneous sampling.

48. Shunt complication
• Overdrainage : low pressure headache
• Subdural hygroma / hematoma (d/t collapse of
ventricle that cause accumulation of blood / fluid in
subdural space)
• Slit ventricle syndrome : children treated with shunts,
whose ventricle & sub arachnoid spaces are
underdeveloped , resulting in poor brain compliance .
Here , normal fluctuation of ICP are exaggerated .

49. Any shunt blockage may not be evident on scan , as
ventricle fail to enlarge
• Disconnection
• Infection (75% within 1 month) - Staph Epidermidis
• Blockage
• 15-20% require replacement within 3 years
• Failure of valve mechanism
• Hydrocele and hernia
• distal end of shunt in the sac.

50. Endoscopic third ventriculostomy
• Useful in obstructive hydrocephalus d/t aqueduct
stenosis
• A neuroendoscope is inserted into the frontal horn of
the lateral ventricle & then into the third ventricle via
foramen of Monro.
• The floor of the ventricle is then opened between the
mammillary bodies & pituitary recess, which allows
free drainage between third ventricle & adjacent
subarachnoid cistern

51. • Position: supine with head flexed so that
the burr hole site is at the highest point.
• Generally, the width of the third ventricle
and foramen of Monro should be
approximately 7 mm or greater.
• Stereotactic guidance can be used as a
surgical adjunct to access ventricle.

52. • Burr hole made at or just anterior to the coronal
suture and about 2.5–3 cm lateral to the midline.
• Right side burr hole performed.
• Brain cannula is used to puncture ventricle and then
introduce endoscope with sheath.
• Peel-away sheath with a diameter, just slightly larger
than the endoscope, can be used. .
• If any significant hemorrhage occurs, the peel-away
sheath facilitates copious irrigation until the
hemorrhage is cleared.
• Lactate solution used for irrigation using gravity as
opposed to any pressure technique to avoid any
barotraumas to the brain or ventricles

53. • Foramen of Monro identified by confluence of thalamo-striate
vein, septal vein and choroid plexuses.
• Perforation made after negotiating endoscope through the
foramen of Monro.
• Fenestration: between mammillary bodies and infundibular
recess, at the most transparent site.
• Basilar artery identified to avoid an injury and the fenestration
made anterior to the artery complex.
• Microvascular Doppler probe: to locate basilar artery
• Position of dorsum sellae identified by gentle probing by the
blunt instrument, such as bipolar forceps if Doppler is not
available.
• Fenestration should be made just posterior to dorsum sellae.
• Water jet dissection technique can be used to prevent an injury
to vessel if the floor is thick and opaque

54. • The third ventricular floor is penetrated bluntly to
avoid vascular injury.
• Although thermal or electric energy are avoided ,
laser assisted third ventriculostomy was found to
be safe and effective.
• An initial fenestration is dilated up to
approximately 5 mm or more by using French
Fogarty catheter.
• An ultrasonic contact probe (NECUP-2) can be
used to create minimal and controlled lesion in
third ventriculostomy

57. • Re-blockage is common
• Less chance of infection
• Complication : damage to basilar artery
or fornicial damage resulting in
permanent memory impairment

58. Other new modalities
• Endoscopic aqueductoplasty ( 3 Fr Fogarty
catheter)
• Endoscopic aqueductal stenting
• Endsopic septostomy