1. Spine Surgeon Prospectives
Chiari Malformations
Spine Surgeon Prospectives
Tariq Elemam Elshafey Awad
ESA / SCU Joint COURSE
Cervical Spine Surgical Procedures
Assist. Prof. of Neurosurgery & Spine Surgery
Suez Canal University
Alex. Desert Road , July, 2017
Al-Solaymaneyah Golf Resort

2. Objectives I aim to present overview of Chiari 1 malformation
Etiology – Clinical presentation – Management
When to suspect CM in a case of spine deformity ?
Curve progressision in Scoliosis with CM
How to manage spine deformity with CM ?

3. Chiari I Malformation
Tonsillar herniation >5 mm inferior to the plane of the foramen magnum (basion-opisthion line)
No associated brainstem herniation or supratentorial anomalies
Hydrocephalus uncommon 10%
Hydrosyringomyelia common
Chiari 0 M

4. Chiari 2 Malformation Chiari 3 Malformation Chiari 4 Malformation
Herniation of the cerebellar vermis, brainstem, and 4th V through the FM
Associated with MM & multiple brain anomalies
Hydrocephalus & syringomyelia very common
High cervical or occipital encephalocele containing herniated cerebellum & brainstem
Chiari 4 Malformation
Sagittal MRI demonstrating the Chiari II malformation. Note the hindbrain hernia into the neck and small cerebellum. Also note the absence of significant portions of the corpus callosum, a nearly vertical straight sinus, and an enlarged massa intermedia.
The low occipital/high cervical sac containing herniated contents of the posterior fossa has ruptured, with the contents exposed.
Chiari 0
Chiari 1.5 cerebellar tonsillar herniation (as seen in Chiari I malformation) along with caudal herniation of some portion of the brainstem (often obex of the medulla oblongata) through the foramen magnum.  Tonsillar descent more than 12 mm – 6 mm type 1
Hypoplasia or aplasia of the cerebellum & tentorium cerebelli

5. Nishikawa underdevelopment of occipital somites within the paraxial mesoderm creates a small posterior fossa
and CIM. (association of CIM with other spine, skull, somatic, and craniofacial abnormalities, which are the result of mesodermal maldevelopment.
1. a small posterior fossa
a) underdevelopment of the occipital bone due to a defect in the occipital somites originating from the para-axial mesoderm
b) low lying tentorium (the roof of the p-fossa)
c) thickened or elevated occipital bone (the floor of the p-fossa)
d) space occupying lesion in p-fossa: arachnoid cyst (retrocerebellar or supracerebellar5), tumor (e.g. FM meningioma or cerebellar astrocytoma), hypervascular dura
2. has been described with just about anything that takes up intracranial space a) chronic subdural hematomas b) hydrocephalus
3. following lumboperitoneal shunt or multiple (traumatic) LPs6: acquired Chiari 1 malformation (may be asymptomatic)
4. arachnoid web or scar or fibrosis around brainstem and tonsils near FM
5. abnormalit ies of the upper cervical spine a) hypermobility of the craniovertebral junction b) Klippel-Feil syndrome c) occipitalization of the atlas d) anterior indentation at foramen magnum: e.g. basilar invagination or retroversion of the odontoid process
6. Ehlers-Danlos syndrome
7. craniosynostosis: especially cases involving all sutures
8. retained rhomboid roof: rare

6. Signs & Symptoms Occipital & upper cervical pain (60-70 %)
often induced by Valsalva maneuvers
such as laughing, sneezing, coughing.

7. Asymptomatic 30%

8. Reestablish bidirectional CSF flow across the craniocervical junction.
PFD PFDD

9. 38 Yrs old M 2 yrs quadrimyelopathy + upper Cerv. pain

10. Chiari-associated spinal deformities are sometimes encountered
a - Standing postero-anterior radiograph of a 13 year old girl with “typical” coronal plane findings of adolescent idiopathic scoliosis.
b – Standing lateral radiograph showing proximal thoracic kyphosis, “atypical” for adolescent idiopathic scoliosis.
c – Lateral clinical image of 13 year old girl with proximal thoracic kyphosis.
d – T2-Weighted MRI of this young woman, showing Chiari-I with syringomyelia.
MRI is expensive and with children often involves sedation,
(not used routinely on scoliosis patients).

11. 6 characteristics that are atypical in scoliosis :
Association between Chiari/SM and scoliosis in children is well documented
6 characteristics that are atypical in scoliosis :
Early onset, <10 yrs
Rapid curve progression (increases >1 ˚ / m)
Atypical curve pattern, e.g. a single left thoracic curve
A kyphotic component
Severe curves despite immaturity (a Cobb angle of > 45 )
Abnormal neurological changes, e,g, altered or absent reflexes
Chronic, disturbing back pain or headache
early onset (n = 4),
rapid progression (n = 19),
pain (n = 17),
other neurologic symptoms or signs (n = 12),
associated syndromes (n = 4),
a convex left thoracic or thoracolumbar curve (n = 18),
a kyphotic component (n = 7),
and pedicle thinning (n = 4)

12. Why does CM1 or SM have scoliotic curve?
The location and size of the major curve of the scoliosis is not correlated with
CM severity
the type and the size of the syrinx
Syringomyelia is often present; however, it may be absent
The convex side of the major curve tended to be on the same side as the syrinx and as the unilateral neurologic abnormality.
role of sp. cord dysfunction in the pathogenesis of syrinx-associated spinal deformities.
Configuration of the syrinx. a Distended type. b Moniliform type. c Slender type. d Circumscribed type
Muscle biopsy evidence of denervation in the concavity

13. Management Observation ? Bracing?
PFD ± Syrinx Drainage is recommended.
Spinal fusion is reserved for those curves that progress to deformities greater than 50 ˚
Syringomyelia in a child with scoliosis and Chiari I. The arrow points to the holocord syrinx.
Plain X-ray shows a child with scoliosis secondary to his CM and SM.

14. Management Rational
Possibility of improvement. In young patients (<10 yrs) and/or those with smaller coronal Cobb angle (<40 ˚), PFD may lead to resolution of the spinal deformity.
Scoliosis surgery may be associated with a higher risk of postoperative deficit and intraoperative neurological monitoring may be difficult.

15. Management
SM associated curves are more likely to progress after fusion than idiopathic curves > Consider longer fusion (extended) + Close F/U is needed
After initial improvement, some curves will begin to worsen over time, necessitating careful follow-up until the completion of growth.
levoscoliosis

16. Take home message
Lack of hypokyphosis ≈ Strongest predictor of CM or SM in setting of scoliosis
Scoliosis surgery is safe when preceded by PFD & intraoperative monitoring is used
Curve improvement after PFD is uncommon in curves > 40˚. Bracing is not effective

17. Take home message
SM associated curves are more likely to progress after fusion than idiopathic curves > Consider longer fusion (extended) + Close F/U is needed
early diagnosis & decompression of a CM in scoliosis patients especially under the age of 10 is crucial and may decrease the curve size and limit scoliosis curve progression.

18. Thanks