Well descriptive power point presentation for fresh neurosurgery residents across the world with very basic knowledge of Chiari malformations and its types and principles of the management and management of its associations.

1. CHIARI
MALFORMATIONS
Dr. Shaheer Anwar

2. Introductio
n• These comprise a group of abnormalities involving the
rhombencephalon (hindbrain) and the contents of the CV
junction.
• Presentlythere is no consensus regarding the precise
definition, classification, etiology and the surgical
management .
• Series of hindbrain anomalies
• Four types•

3. Definitions of Chiari
malformations• Chiari type I
tonsillar herniation below foramen magnum.
no associated brainstem herniation or supratentorial
anomalies. hydrocephalus uncommon.
• Chiari type II
caudal herniation of brainstem, cerebellar vermis, and fourth
ventricles. associated with myelomeningocele & intracranial
anomalies. hydrocephalus & syringohydromyelia common
• Chiari type III
occipital encephalocele with many of same intracranial anomalies seen
with type II malformation.
• Chiari type IV
hypoplasia / aplasia of cerebellum with no hindbrain herniation

4. CHIARI 1
Tonsillar herniation.

5. Chiari I
Malformation

7. Associated anomalies –
Chiari l• Skull
– Basilar skull and cv junction anomalies
(50%)
• Underdevelopment of supraocciput and
exocciput
• Shortening of supraocciput
• Shorter clivus
• Smaller and shallow posterior fossa
• Empty sella
• Platybasia
• Basilar impression
• Midline occipital keel
• Accessory occipital condyle

8. Associated anomalies –
Chiari l
• Spine
– Klippel-Feil deformity
– Atlantoaxial assimilation
– Retroflexion of odontoid
process
– Thickening of ligamentum
flavum
– Scoliosis

9. Associated anomalies –
Chiari l
• Ventricle and cistern
– Hydrocephalus (3-10%)
– Elongated 4th ventricle
– Retrocerebellar CSF space are
obliterated or diminished

10. Associated anomalies –
Chiari l
• Meninges
-- Elevated slope of tentorium
– Thickening of arachnoid at foramen magnum
– Constricting dural bands at level of
foramen magnum and posterior arch of
atlas
– Veils of arachnoid that obstruct fourth
ventricular outlet

11. Associated anomalies –
Chiari l
• Spinal cord
– Syrinx (50-
75%)

12. Associated anomalies –
Chiari l
• Brain
– Elongated midbrain, pons and medulla
– Medullary kinking or flattening
– Tonsils- peg like.

13. CHIARI
MALFORMATION II
- Caudal herniationof brainstem,
cerebellar vermis, and fourth ventricles.
- associated with myelomeningocele
& intracranial anomalies.
- hydrocephalus&
syringohydromyelia common

14. Chiari II
Malformation

15. Associated anomalies –
Chiari ll• Skull
– Craniolcunia or luckenschadel- copper beaten
appearance of calvaria
– Anterior scalloped frontal bone (lemon sign )
– Scalloping of pterous and jugular tubercle
– Enlarged FM
– Notched opisthion
– Elongated clivus with concavity
– Lower inion
– Basilar impression
– Assimilation of atlas

16. Chiari IISupratentorial
pathology• Luckenschadel or Lacunar skull
– result of abnormal radial growth of the skull, seen in upto 85% of
cases
– Focal areas of cortical thinning and scalloped appearance of the
skull
– most prominent at birth, may resolve with age
– not a result of raised ICP and hydrocephalus

17. Banana
sign
Normal fetus

18. Chiari II
Malformation

19. Genetics of
Chiari
• Familial occurrence
• Concordance in twins and triplets
• Association with other genetic
disorder
– Spondyloepiphyseal dysplasia tarda
– Hadelu-Cheney syndrome
– Klippel-Fiel syndrome
– achondroplasia

20. Chiari
III• herniation of brainstem and cerebellum
into a posterior encephalocoel.
• Very rare; most severe form.
Management difficult.
• Differentiate from cervical myelomeningocoel.
• Severe neurological, developmental and
cranial nerve defects, seizures and
respiratory insufficiency.
• Treatment- well planned encephalocoel
closure

21. CHIARI 3: occipital encephalocele
with

22. Chiari
IV• cerebellar hypoplasia or aplasia(1896).
Post fossasizenormal.
• No hindbrain herniation.
• Tentorium cerebelli also
hypoplastic.

23. CHIARI 4 :Cerebellar hypoplasia/

24. Clinical
features

25. Chiari
I• HEADACHE
Most common symptom
(81%) Sub occipital
Radiation to vertex / neck / retro-
bulbar Heavy crushing / pressure
like
↑ed by physical exertion, Valsalva
maneuver, head dependency
and sudden changes In
position

26. Chiari
I• Spinal cord/ syrinx
– sensory
• Numbness: initial complaint, asymmetric, hands/arms
• Dissociated sensory loss: loss of pain and temp, preserved touch
and JPS
• Dysesthesia and proprioception disturbances – advanced stage
• Deep and boring/ itching/ burning
• C2 dysesthesia
• Interscapular pain
• All pain exacerbated by cough and sneeze
• Valsalva or severe cough may alter findings
• Charcot joints: <5% of patients

27. Chiari
I• Spinal cord/ syrinx
– Motor:
• Difficulty in performing fine motor tasks in
UL
• Weakness of hand and/or arm
• Wasting – distal and proximal
• Fasciculations
• Absent DTRs
• UMN lower extremities
• Horners’ – complete or partial
• Bowel and bladder control normal
• Occasionally LMN in lower extremities

28. Chiari
I• Brain stem/ CSF flow/ FM
– Cough headache
– Neck and arm pain – non dermatomal “deep and
boring”
– Down beat nystagmus
– Hoarse voice
– Palatal dysfunction
– Tong– fasciculations/ atrophy
– Dysphagia
– Hiccups
– Severe snoring
– Respiratory dysrhythmias
– Facial numbness
– Drop attacks
– Dysarthria

29. Chiari
I• Cerebella
r:
– Nystagmus:
– Ataxia
– Dysmetria

30. Chiari
II• Commonly presents in infancy, childhood and
adolescence
• May stabilize or improve after 6 to 12mths
• Risk of apneic attacks, dysphagia with aspiration
pneumonia,
life threatening vocal cord paralysis
• Leading cause of death in treated myelodysplastics
within first 2 yrs of life

31. Clinical
features
Brain stem
45%
cerebellar
7%
spinal cord
48%
Chiari
II

32. Chiari
II• Brain stem
– Nystagmus.
– Poor sucking/ dysphagia/ aspiration
– Arching of head/ fixed retrocollis/ ophistotonus
– Apneic spells – cyanosis/anoxic seizures – exhausted-
sleeps
– Vocal cord abductor palsy
– VII nerve paresis
– Dysconjugate eye movements
– Mirror movements

33. Chiari
II• Spinal cord/ syrinx
– Spasticity of upper extremities.
– Weakness of lower extremities.
– Persistent cortical thumb.
– Suspended dissociated sensory loss.
– Upper extremity weakness and wasting of hand
muscles.
– Scoliosis.

34. Chiari
II• Cerebellar:
– Nystagmus: horizontal or rotary
– Appendicular ataxia: “falls so much”, gait
changes
– Dysmetria: inability to feed himself

35. Management of Chiari-Syrinx
Complex

36. Establishment of
Diagnosis
• X ray CVJ and cervical spine...
• Computed Tomography Scanning
(CT)
• Magnetic Resonance Imaging (MRI)

37. MR
I
• Investigation of choice to assess the
degree of tonsillar descent
• T2 weighted saggital MRI of the spine...
• Helps to screen the whole of the spine
and brain for any other associated
anomaly of the neuraxis or presence of
hydrocephalus
• Septations and flow voids within the
syrinx can be seen

38. Indications for surgical
Intervention• Progressive neurological
deficit
• Progressive enlargement of
syrinx.

41. PFD vs
PFDD• Durham and Fjeld-Olenec : meta-analysis of
studies that directly compare cohorts of pediatric
patients who underwent PFD with PFDD.
• Patients who undergo duraplasty are less likely
to require reoperation (2.1% vs. 12.6%) for
persistent or recurrent symptoms but are more
likely to suffer CSF- related complications
• No statistical difference in clinical outcomes
between the two groups, specifically with regard
to symptom improvement and syringomyelia

42. • clinical improvement were 65% in the PFD
patients and 79% in the PFDD patients
• Syrinx resolution :56% in the PFD patients and
87% in those undergoing PFDD.

44. Selection of Surgical
Procedure
• Depends on whether chiari is associated
with syrinx or not.
• Also on the type and degress of tonsillar
descent.
• The key is to decompress the posterior fossa
and CVJ adequately, and to establish
normal CSF flow across the region of
formen magnum.

45. Various procedures
adopted
• FMD alone
• FMD with lax duroplasty
• FMD with arachnoid adhesiolysis
and lax duroplasty
• FMD with tonsillar resection, and lax
duraplasty
• FMD with any of the above and
additional removal of C2.
FMD = Suboccipital craniectomy encompassing the
foramen magnum rim and C1 posterior arch

46. Additional procedures for
associated
problems• Hydrocephalus
– VP shunt
– ETV (Missimi et al - NS 2011)
• CVJ instability
– Posterior fusion

47. Surgical
Technique
• Bony decompression
• Dural procedures
• Arachnoid handling
• Dealing with the
tonsils

48. Positionin
g

49. Skin
Incision
• Extent:
– Just below inion
– Just past the C2
spine

50. Muscle
dissection

51. Bone
Removal

52. Dural
Opening

53. Dural
Opening

54. Bleeding at
durotomy
• Cerebellar dura may have venous lakes
• Circular or occipital sinus may bleed
profusely
• Control
– Proceed slowly
– Bipolar
– Metal Clips
– Figure of 8 stiches

55. Intradural
exploration
• Arachnoid opening
– Under
magnification
– Midline
– Avoid adherant
PICA
– Only sharp
dissection

56. Dural
Closure

57. Wound
closure
• Layered
closure
– Muscle
– Facia
– Subcuticular
– Skin

58. Postoperative
complications
• Early
– CSF Leak
• Address HCP
• Resuture
• Lumbar drain
– Meningitis – Infective /
Chemical
• Non autologous graft
• Dura not closed
• Meticulous and clean procedure

59. Postoperative
Complications
• Early
– Lower cranial nerve
dysfunction
– Brainstem dysfuctions
– Hematoma

60. Postoperative
Complications
• Late
–Symptom recurrence
• Occur after initial
improvement
• Due to:
– New or enlarging syrinx
– CSF obstruction due to
scarring
– Cerebellar ptosis
–Pain

61. Recurrent or Unresolved Chiari
Failed procedure
• Causes:
– Inadequate decompression
• Bony
• Soft tissue
– Reformation of arachnoid scars
– Lack of CSF flow normalization despite
adquate soft tissue and bony
decompression
• Management
– Revision surgery
– Shunting of the syrinx

62. Follow
up• Chiari I
• Pts without a syrinx: follow up at 1, 6 &
12 months, then every 12 to 24 months
;no need of repeat imaging (if there is
symptomatic improvement)
• Pts with syrinx: follow up MRI in 6
to 12 months.No further imaging if
symptoms improve or syrinx
decreases in size significantly.

63. THANKYOU