Syringomyelia

SYRINGOMYELIA

FOR NEUROLOGISTS AND NEUROSURGEONS

1. SYRINGOMYELIA
Dr SHANAVAS C
MCh TRAINEE
GMC, KOZHIKODE

3. INTRODUCTION
•‘Tubular cavitations’ of spinal cord filled with
CSF
•Prevalence –9/1,00,000 people
•Incidence -0.44 cases/year
•Etiology –Traumatic , CVJ anomaly
•Prognosis and response to surgery –Depends
on Basic pathophysiology
•Associated with chiari I malformation in 60%-
70% of patients

4. •Hydromyelia –Simon –lined by ependymal
cells –Dilatation of central canal
•Classical Syringomyelia –Lined by glial tissue
•Hydrosyringomyelia –More accurate

6. CLASSIFICATIONS
•Barnet et al –Communicating and non-
communicating
•Milhort et al-Communicating , non-
communicating , Atrophic
•Batzdorf et al-a) associated with CVJ anomaly
•b) abnormalities at spinal level

7. Modified Milhoret classification
1. Communicating syringomyelia
2.Non communicating syringomyelia
3. Atrophic cavitations(Syringomyelia ex-
vacuo)
4. Neoplastic cavitations

8. Aetiology
•A) Abnormalities at CVJ
•Bony abnormalities-Basilar
invagination,Platybasia,Bone tumours
•Arachnoid scarring-Trauma, infection, inflammation
•Subarachnoid space compression-Hind brain
impaction-Chiari I malformation
•Fourth ventricular cyst-Dandy walker malformation,
Tumours-Extrinsic and intrinsic

10. •B) Abnormalities at spinal level
•Arachnoid scarring-Trauma, surgery,
infection, inflammation
•Subarachnoid space -Tumours-Extrinsic and
intrinsic, spondylosis

11. •Traumatic syrinx-More common in thoracic
spine-develops in the vicinity of spinal cord
injury
•Myelomeningocele –Chiari II malformation-
Cervical and thoracic syrinx
•Close D/d –intramedullary spinal cord cyst –
protein rich cyst fluid generated by neoplasm
itself

13. Mechanism of syrinx formation
A)Associated with CVJ anomaly
•Nearly 60% associated in Chiari I malformation
•Chiari I cerebellar tonsillar herniation
•Chiari II malformation-tonsillar herniation,
buckling of medulla,beaking of tectum, large
massa intermedia, hydrocephalus -
meningocele

14. •Gardner -Hydrodynamic theory-high pressure
waves from the fourth ventricle passing
through the opening at the rostral end of the
central canal produced progressive
enlargement of the fluid collection
•the fluid entering the spinal cord parenchyma,
driven by the arterial pulsations, would
coalesce and rupture into and therefore
enlarge the central canal

15. •Milhorat --> CSF was continually produced by
the ependymal cells lining the central canal -->
the expansion of the central canal occurred in
segments isolated by occlusion or stenosis at
each end, such as occurs with viral
ependymitis

16. •Ball and Dayan
•CSF fluid dissects into the spinal cord
parenchyma along the Virchow Robin space,
when tonsillar impaction prevented the
upward escape of CSF

17. Syringomyelia Related to Primary
Spinal Abnormalities
•the necrotic tissue and the haematoma within
the injured spinal cord --> resorbed and
replaced by a cystic cavity
•“spinal-spinal pressure dissociation” model -->
Rapid pressure equilibrium in the
subarachnoid space proximal and distal to the
scar --> the CSF to move into the lower
pressure environment of the central canal
region of the spinal cord.

18. •a syrinx like lesion can develop, following
atrophy of the swollen spinal cord which has
undergone demyelination.
•The predilection of inflammatory lesions of
the spinal cord to produce secondary necrosis
and subsequently syrinx may be a
consequence of the tight investment of the
cord by pia.

19. Mechanism of Syrinx Propagation
•Gardner -Hydrodynmic theory -driven by the
arterial pulsations, would coalesce and
rupture into and therefore enlarge the central
canal-With Cine gated MRI -Obselete

20. •Williams -normal physiologic events, such as
coughing and straining --> the pressure
differentials initiated by epidural venous
distension --> to and fro fluid dissection within
the spinal cord referred to as slosh.
Oldfield --> systolic pressure wave of the
subarachnoid CSF applied against the surface
of the spinal cord --> forces the syrinx fluid to
move caudally within the cyst

21. SYMPTOMATOLOGY
•Most patients with hind brain anomaly related
syringomyelia become symptomatic in young
adulthood.
•The mean age at onset of symptoms was third
decade
•more common in males.

23. •progresses slowly and the course may extend
over many years
•a more acute course, especially when the
brainstem is affected
Syringomyelia usually involves the cervical area.

24. •The majority of cases of syringomyelia are
associated with Chiari malformation.
•Therefore, it is essential to differentiate
symptoms predominantly due to central spinal
cord cavitations from those due to hindbrain
descent.

25. Symptoms Predominantly Due to
Central Spinal Cord Cavitation
•dissociated sensory loss, amyotrophy and
spastic paraparesis
•Initially Unilateral -later stages, with a larger
syrinx, the symptoms may become bilateral
•Dissociated sensory deficit is due to damage
of the spinothalamic fibres (conveying pain
and temperature sensation) in the anterior
commissure.

27. •The ascending sensory fibres involved with
light touch and proprioception are usually
spared.
•The anterior commissure is damaged at the
levels of the syrinx but remains intact rostrally
and caudally.
•The resulting sensory deficit has been
described as “cape like” or as a “suspended
sensory level of cuirasse” because it typically
involves the breast-plate distribution.

29. •Posterior column involvement --> position and
vibration sense lost, astereognosis
•Amyotrophy of the muscles --> damage of the
anterior horn cells --> usually begins in the
hands and extends into the proximal upper
extremities.

30. •Lower extremity motor symptoms --> destruction or
compression of the corticospinal tracts in the lateral
columns --> asymmetric spastic paraparesis with
absent superficial reflexes, increased deep tendon
reflexes and extensor plantar responses.
•Respiratory insufficiency --> related to changes in
posture,may occur.
•Sphincter disturbance may occur as a late finding.

31. •Complex regional pain syndrome(CRPS) --> reflex
sympathetic dystrophy --> oedema, changes in skin
blood flow, abnormal pseudomotor activity in the
region of the pain, and allodynia or hyperalgesia ->
Usually in Distal aspect of an affected extremity.
•If the syrinx extends into the medulla, syringobulbia
develops, with symmetric limb weakness, palatal
weakness, wasting of the tongue, dissociated
trigeminal sensory loss and nystagmus.

32. Lower cranial nerve signs and symptoms are seen
particularly with basilar invagination --> the syrinx
cavity can extend beyond the medulla in the
brainstem into the centrum semiovale
(syringocephalus).
Clinical symptoms associated with Chiari malformation
include headache, neck pain, cerebellar dysfunction,
nystagmus, spasticity,ataxia, diplopia and bulbar
palsies (dysphagia).
These symptoms tend to develop in adolescence and
early adulthood

33. IMAGING
•Magnetic resonance imaging is the best
imaging modality for diagnosis of
syringomyelia
•demonstrate the extent of syrinx along with
associated soft tissue abnormalities of the
craniovertebral junction, neoplasms, stenosis
and arachnoid scarring.

35. •Imaging of the entire rostrocaudal extension
of the cyst or cysts is important.
•It also helps to see the flow and septations
inside the syrinx.
•Gadolinium enhanced images are indicated if
a tumour is suspected
•Magnetic resonance angiography may be
helpful in cases of syringomyelia associated
with vascular lesions.

36. •Myelography with delayed CT performed after 4–12
hours may be used in patients who are unable to
tolerate MRI and may demonstrate contrast
accumulation in the cyst.
•Cardiac gated cine mode T2 weighted MRI has been
used to demonstrate CSF flow patterns less
pulsatile flow within the syrinx is associated with a
decreased likelihood of benefit from surgery.

37. •Real-time ultrasonography is rarely used for
imaging syringomyelia. It is technically more
feasible in young children or in thin patients.
•Routine radiographs may demonstrate a
widened cervical canal, bony abnormalities of
the skull and CV junction, platybasia, midline
keel and assimilation of the atlas

38. •The natural history of syringomyelia varies from
spontaneous and complete regression to progressive
devastating neurologic deficits.
•Lord Brain described it, “relentlessly progressive”.
•The possibility that a syrinx may spontaneously
disappear may warrant a more conservative
approach in certain instances.
•Patients with a nearly normal sized spinal cord --> a
benign clinical course
•if significant spinal cord dilation was seen --> the
symptoms tended to progress.

39. MANAGEMENT
•Treatment depends on the cause
•No clear consensus

40. SELECTION OF PATIENTS FOR
SURGERY
•Progressive neurological deficits
•Sequential images show progressive
enlargement of syringomyelia
•Patients with little or no neurological deficits
should be followed up with serial neurological
examination

41. •Radiological syrinx grading assessed by
cyst:cord and cord:canal ratios
•Lack of correlation between the clinical and
radiological grades pre as well as
postoperatively
•Radiological reduction in the size of syrinx far
outweighed clinical improvement
•Prognosis depends on clinical grading more
than radiological grading

42. •Main goal of surgery is to arrest progression of
neurological deficits
•Suboccipital headache-tonsillar impaction –
responds to PF decompression
•Pyramidal tracts signs and spinothalamic
sensory loss –Pressure of cyst on these tracts
get reduced
•Weakness and atrophy of hands –destruction
of anterior horn cells-doesn’t improve

43. •Dysesthetic pain –Poorly respond with
surgery
•Lower cranial nerves –Brain stem symptoms –
Candidates of surgery

44. Surgical management of Syringomyelia
associated with CVJ anomaly
•Symptomatic patients are treated surgically
•Top down rule
•Hydrocephalus –VP shunt
•Suboccipital decompressive craniectomy +/-
Cervical laminectomy +/-Expansive duraplasty
•Dural opening –Controversial
•Dural bands –freed
•Arachnoid adhesions release, manipulation of
tonsils -Controversial

45. •A tube or sialastic wick placed in the midline
in the fourth ventricle outlet.
•Fourth ventricle to subarachnoid shunting
•Plugging of obex, excision of tonsils –
controversial , not recommended now a days
•If no neurological improvement after 3-6
months –Syringoperitoneal shunt may be
suggested

47. Surgical management of Syringomyelia
associated with Primary spinal abnormality
•Syringostomy
•Shunting –Syrinx to Subarachnoid space,
Pleural and peritoneal space
•Endoscopic release of septations

48. •Syringostomy –Oldest surgical site
•Laminectomy at appropriate site dorsal
longitudinal incision through the thinned out
spinal cord spinal cord incisions are made
in to midline or just posterior to dorsal root
entry zone
•Myringostomy tube may be inserted –
Ventureyra et al

49. •Aschoff and Kunze et al –41% improvement
•25% stabilisation
•36% deterioration

50. Shunting procedure
•Exposing spinal cord at max diameter of syrinx
by laminectomy or hemilaminectomy Small
myelotomy done at midline or near dorsal
root entry zone proximal catheter may be
inserted caudal or cephalad
•Distal end tunneled in to subarachnoid space
or pleural space or peritoneal space

52. •Terminal ventriculostomy –
•Appropriate for syrinx without Chiari
malformation

53. •Increase CSF flow –open and endoscopic
dissection of subarachnoid dissections-
expansile duraplasty –tacking of dura

54. •Abe et al
•Type I –Syringomyelia Associted with Chiari –
Posterior fossa decompression
•Type II-Ass. With Basal arachnoiditis –
Cisterna magna narrowed by scar tissue -
Posterior fossa decompression –Fouth
ventriculo subarachnoid shunt

55. •Type III –Syringomyelia communicating with
fourth ventricle with hydrocephalus –Posterior
fossa decompression, dissection of dural band
obstructing foramen of Magendie+ /-plugging
of obex

56. •Type IV –Arachnoid scarring around spinal
cord with normal CVJ –
•If localised –Syringosubarachnoid shunt
•If Not localised –Syringoperitonel shunt
•Type V –No associated anomalies-
Syringosubarachnoid shunt or
lumboperitoneal shunt

57. OUTCOME OF SURGERY
•Pain –81.5 %improved , 7.4% worsened ;
11.1% -stabilised
•Motor strength –70 % improved , normal in
21 % , worsened in 6 %, Unchanged –3%
•Sensation –improved 6% ; unchanged 61%;
normal -29% , worsened in 4%

58. Surgical failure and complications
•Cerebellar ptosis –Large craniectomy
•Tethering and scarring of cervical spinal cord
•Recurrent syringomyelia
•Instability of CVJ
•Regeneration of foramen magnum
•Psuedomeningocele

59. •Shunting procedure-kinking of tube, displaced
•Blockage internally –arachnoid scar,
proteinaceous fluid, tissue debris
•Overdrainage of CSF –Hind brain herniation
•Cardiopulmonary arrest
•CSF leak and fatal infection
•Recurrence of cyst

60. THANK YOU