Syringomyelia

Definition

 

Progressive and  chronic disorder associated with cord cavitation & gliosis

 

Effects

 

Muscle wasting

Dissociate anaesthesia

Scoliosis

Neuropathic arthropathy

 

Epidemiology

 

M > F

No familial tendency

 

Aetiology

 

1. Idiopathic

 

2. Hindbrain Herniation / Arnold- Chiari Malformation

- abnormal pressure & circulation of CSF

 

3. Post-Traumatic

- occurs in 3%

- ? due to subarachnoid block 2° to adhesive arachnoiditis

- more common in complete tetraplegics

- delayed presentation of deterioration

- 3/12 - 30 years

 

4. Arachnoiditis

5. Intramedullary Tumour

6. Extrinsic Compression With central cord necrosis

7. Necrotic Myelitis

 

Arnoldi-Chiari Malformation 

 

Congenital abnormality of Cerebellar Tonsils 

- herniation of medullary tonsils through foramen magnum into cervical canal

- block CSF flow through foramen Lushka & Malgagne blocked

- often need AV shunt

 

Type I  

- communicating

 

Arnold Chiari Type 1 MRI

 

Type II  

- non communicating

- usually larger and associated with spina bifida

 

Arnold Chiari Malformation with syrinx

 

Pathology

 

Cord damage

- anterior dissection of cavity with interruption of decussating spinothalamic fibres

- effects pain & temperature 

- extension into lateral corticospinal tracts 

 

Most common in lower C Spine

- may progressively extend up to medulla & down to lumbar 

- fluid-filled tubular cavity

- separate from but usually communicating with central canal

 

Spastic Paraparesis

- involvement of 2° order neurones

 

Pain with causalgia

 

Consequences

 

Dissociative sensory loss

Spastic paraparesis

Neuropathic joints especially GHJ

Scoliosis as syrinx is irritative

- scoliosis not due to muscle imbalance as neurology most commonly normal

 

Histology

 

Cystic space

- lined by thick layer of glial tissue

- gliosis with tendency to infiltrate white matter

 

Associations

 

Craniovertebral anomalies

Platybasia

Hydrocephalus

Myelomeningocoele

 

Cause of deterioration in Spina Bifida

 

Shunt malformation

Arnold Chiari

Cord Tether

Diastomatomyelia 

Neuroenteric cyst

Syrinx

 

Clinical Features

 

Classic Triad

 

1.  Dissociate sensory loss in cape distribution

- loss of pain and temperature

- preservation of light touch (dorsal columns) 

- arms and trunk with cervical

- legs with lumbar

 

2.  Muscle wasting / weakness with diminished reflexes 

- in UL due to direct pressure on anterior horn cells

 

3.  Atypical high thoracic kyphoscoliosis

 

Site of syrinx

 

1.  Cervico-Thoracic

- dissociate sensory loss in arms & trunk

- weakness & wasting of arms

- absent abdominal reflexes

 

Syrinx Thoracic MRI SagittalSyrinx Thoracic MRI Axial

 

2.  Lumbar

- dissociate lumbosacral sensory loss

- weakness & wasting of legs & pelvic girdle

- diminished reflexes / Babinski negative

- impaired bowel & bladder function

 

3.  Cervico-Medullary 

- AKA syringobulbia

- palatal & vocal paralysis / dysarthria

- nystagmus / dizziness / tongue weakness

 

Cervicomedullary Syrinx 1Cervicomedullary Syrinx 2Cervicomedullary Syrinx 3

 

X-ray

 

Spine

Base of skull

 

MRI

 

Most sensitive investigation

- main differential is oedema

- need T1 image

 

Look for obstructions

- ACM

- spinal cord tumours

 

DDx

 

Amyotrophic Lateral Sclerosis / Motor Neurone Disease

MS

Cervical Myelopathy

Thoracic Outlet Syndrome

Klippel-Feil Syndrome

Cord Tumour

Brainstem Infarct

 

Operative Management

 

Indications

 

Rapid progression of neurology

Short History

Respiratory compromise

Pseudobulbar Palsy

Pre-spinal corrective surgery

 

Technique

 

Shunt

- Syringo-Cisternal

- Syringo-Peritoneal

 

Suboccipital decompression & C1-2 laminectomy

 

Orthopaedic Implications

 

Neuropathic Joints

 

Syrinx is most common cause of UL charcot joint

- shoulder

- elbow

- hot swollen joint may be first presentation of syrinx

 

DDx

- infection

- peripheral neuropathy - DM / Leprosy / Tabes dorsalis

 

Scoliosis

 

Scoliosis is usually 1° Presentation of syrinx

- curve is idiopathic type

- often left sided thoracic

- corresponds with level of syrinx

 

Males > Females

- 25% if < 10 year old

- 20% males with scoliosis have syrinx compared with 2% of girls

 

Neurological deficit usually subtle or absent

- axillary sensation absent

- absent abdominal reflexes

 

Treatment

- must correct syrinx first

- malignant progression if syrinx untreated

- cyst rupture during scoliosis surgery may be fatal

- progresses like idiopathic once syrinx treated