1. Presented by Abdulgadir F. Bugdadi
Chiari Malformation
Presented by
Abdulgadir F. Bugdadi

2. Types
Consists of 4 types. Probably unrelated to each other.

3. Type 1 chiari malformation

4. Epidemiology Age of presentation ( 12 – 73) average age is 40 years.
Adults
Slight female preponderance.

5. Feature Heterogeneous entity but the common feature is ;
Impaired CSF Circulation through Foramen magnum.

6. Components
Caudal displacement of Cerebellum with tonsillar herniation below foramen magnum.
( > 5mm below the foramen magnum , not essential and nor diagnostic).
Syringomyelia (30%-70%)….
Hydrocephalus (7% - 9% in patients with 1&2)

7. Etiology Different etiologies can be with it; Small posterior fossa ….
Intracranial space occupying lesions ..
Lumboperitoneal shunt or multiple LP. “acquired, usually asymptomatic”.
Arachnoid web or scar or fibrosis around brainstem and tonsils around FM.

8. 5. Abnormalities of upper cervical spines …. 6
5. Abnormalities of upper cervical spines …. 6. Ehlers - Danlos syndrome. 7. Craniosynostosis.

9. Symptoms Asymptomatic 15% – 30%. Etiology of Symptoms Compression of
Brain stem
Hydrocephalus
Syringomyelia %
Symptom
69%
Pain (H/A ‘34%’, neck, gridle, arm, leg)
56%
Weakness
52%
Numbness
40%
Loss of temperature sensation
Unsteadiness
15%
Painless burns
13%
Diplopia 8%
Dysphasia 7%
Tinnitus 5%
Vomiting 4%
Dysarthria
3% E
Dizziness, Deafness, Fainting, Facial numbness
Asymptomatic 15% – 30%.

10. Foramen magnum compression syndrome
Signs
Etiology of signs
Foramen magnum compression syndrome
(22%)
Central Cord Syndrome
(65%)
Cerebellar syndrome
(11%)
Ataxia, corticospinal and sensory deficits, cerebellar signs and lower cranial nerve palsies.
Loss of pain and temperature sensation, segmental weakness, syringomyelic syndrome or lower cranial nerve palsies ‘11%’.
Ataxia, nystagmus (downbeat), dysarthria.
Normal neurologic exam 10%

11. Imaging MRI ; Diagnostic test of choice.
Abnormalities that can be seen :
Tonsillar herniation.
Hydrosyringomyelia (20% - 30%).
Ventral brain stem compression.
Other findings ; Hydrocephalus or empty sella.

15. Cont.
Other imaging
Cine MRI “CSF flow study”…
Myelography…
CT…

16. Treatment Surgical management. Goal of surgery ;
Decompress the brain stem an reestablish normal CSF flow at the craniocervical junction.
Indication of surgery ;
- Symptomatic.
- Best response…
- symptomatic & stable for years…

17. Surgery performed ;
Posterior fossa decompression (suboccipital craniectomy) +/-
Dural patch grafting.
Laminectomy of C1 (sometimes C2 or C3).

18. Type 2 (Arnold) chiari malformation

19. Feature
Caudally displaced cervicomedullary junction, pons, 4th ventricle and medulla.
Cerebellar tonsils located at or below foramen magnum.
Usually associated with myelomeningocele and often accompanied by hydrocephalus.

20. Theory of pathophysiology
Primary dysgenesis of the brainstem with multiple other developmental anomalies. Not the result of tethering by the associated myelomeningocele.

21. Onset is rare in adulthood

22. Brain stem and lower cranial nerve dysfunction
Symptoms
Symptoms
Dysphagia (69%)
Apneic spells (58%)
Stridor (56%)
Aspiration (40%)
Arm weakness (27%)
Opisthotonos (18%)
Nystagmus
Facial weakness
Weak or absent cry
Etiology of symptoms
Brain stem and lower cranial nerve dysfunction

23. Imaging MRI ; Primary findings: “Z” bend deformity of medulla.
Cerebellar peg.
Tectal fusion “Tectal beaking”.
Interthalamic adhesions.
Elongation/cervicalization of medulla.
Low attachement of tentorium.

26. B. Associated findings ;
Hydrocephalus.
Syringomyelia at cervicomedullary junction.
Trapped 4th ventricle.
Cerebellomedullary compression.
Agenesis/dysgenesis of corpus callosum.

27. Treatment
Insert CSF shunt for hydrocephalus (or check functioning of an existing shunt).
Surgical decompression is recommended for : (Argument)
Neurogenic dysphagia.
Neurogenic stridor.
Apneic spells.
Note:
Before recommending decompression always make sure that the patient has a functioning shunt.

28. Chiari type 3; Chiari type 4;
1. displacement of posterior fossa structures with cerebellum herniated through foramen magnum into cervical canal + high cervical or suboccipital encephalomeningocele.
2. Usually incompatible with life.
Chiari type 4;
Cerebellar hypoplasia without cerebellar herniation.

29. END
Reference