Neurosurgery ModuleMohammed Homoud MBChB,FRCSC,FAANS

Consultant Paediatric Neurosurgeon and Complex Spine

Director of Neurosurgery Department

Prince Sultan military Medical City

Hydrocephalus

Anatomy &

Pathophysiology

Types

Dandy Walker

Clinical

other types

• Hydrocephalus ex vacuo

• Normal pressure hydrocephalus

Chiari Malformation

Chiari I

T“adult-onset Chiari” presenting by 4th decade

downward displacement of the cerebellar tonsils

through the foramen magnum

Chiari I Clinical

symptoms/ suboccipital headache

Neck pain

subjective weakness

numbness, loss of temperature sensation 40-60%

signs/ hyperactive lower extremity reflexes

“Cape”-like sensory loss

nystagmus (downbeat)

gait disturbance, upper extremity weaknes(30-50% )

Chiari I imaging

MRI is diagnostic

compression of brain stem

at FM

Hydrocephalus

Syringomyelia

Descent of cerebellar tonsils

through foramen magnum

Chiari II

“Arnold-Chiari malformation.”Presents in childhood

Usually the younger

S&S/ secondary to brainstem and lower cranial

nerve dysfunction.

Findings (best seen on MRI):

Caudal displacement of posterior fossa structures,

including cervicomedullary junction, pons,

medulla, 4th ventricle, and cerebellar tonsils

Spinal Dysraphism

General

• general term for a family of congenital

malformations of the spine and spinal cord.

• also known as neural tube defects

Causes

Results from failure of the neural tube to close

spontaneously between the 3rd-4th week of in utero

development

Possible etiologic factors:

1-Radiation

2-Drugs

3-Malnutrition

4-Chemicals

5-Genetic determinants (mutations in folate-

responsive and folate-dependent pathways)

Types of Spinal Dysraphism

1-Spina bifida occulta

2-Meningocoele/ Myelomeningocoele

3-Encephalocoele

4-Anencephaly

5-Dermal sinus

6-Tethered cord

7-Syringomyelia

8-Diastematomyelia

Diagnostic Tools

Failure of closure of the neural tube allows excretion

(AFP, acetylcholinesterase) into amniotic fluid

Prenatal screening of maternal serum for AFP during 16-

18 week AOG

AF AFP obtained between 15-20 weeks’ gestation is most

specific

Rostral end of the NT closes on the 23rd day and the

caudal neuropore closes by the 27th day of development

Neural Tube Defects and FA

Periconceptional use of folic acid reduces NT defects

(NTD)by 50%

recomandation: 1-0.4 mg of folic acid daily,

2-Previous pregnancy of NTD 4 mg of folic

one month before pregnancy , until at least the 12th week

AOG( complete neurulation )

Fortification of flour, pasta, rice and cornmeal with 0.15 mg

of folic acid/100 g was mandated in the US and Canada in

1998

Spina Bifida Occulta

Midline defect of the vertebral bodies without protrusion of

the SC or meninges

usually asymptomatic

In some, patches of hair, lipoma, discolouration of skin or

dermal sinus may be present

May be associated with syringomyelia, diastematomyelia, and

tethered cord

Recurrent meningitis of occult origin should prompt careful exam

for dermal sinus tract

Meningocele

meninges herniate through a defect in the posterior

vertebral arches

SC may be normal, or may present with tethering,

syringomyelia, or diastematomyelia

A fluctuant mass that may transilluminate along the

vertebral column

Myelomeningocoele

Most severe form, incidence of 1/4000 LB

Risk of recurrence after one affected child increases to

3-4% and increases to ~10% with 2 previous abnormal

pregnancies

Certain drugs that antagonize folic acid (TMP, AEDs:

CBZ, PHY, Pb, primidone) increase the risk of

myelomeningocoele

Valproic acid cause NT defects in ~1-2% of pregnancies

Myelomeningocoele

May be located anywhere along the neuraxis but

the LS region accounts for 75% of the cases

Extent and degree of the neuro deficit depend on

the location

CM: flaccid paralysis, absent DTRs, sensory

deficit below the affected level, postural abn of

the LE (clubfeet, subluxation of the hips),

constant urinary dribbling and a relaxed anal

sphincter

Myelomeningocoele

HCP in association with a type II Chiari defect develops

in at least 80% with myelomeningocoele

Infants with HCP and Chiari II develop symptoms of

hindbrain dysfunction: difficulty feeding, choking,

stridor, apnea, VC paralysis, pooling of secretions,

spasticity of UEs

Chiari crisis is due to downward herniation of the

medulla and cerebellar tonsils

Management

Requires a multidisciplinary approach: surgeon,

therapist, pediatrician

Surgery: repair and shunting; orthopaedic procedure,

urologic evaluation

GUT: regular catheterization to prevent UTI and reflux

leading to PN and hydronephrosis, urine cult, serum

elec, creatinine, renal scan, IV pyelogram, Utz

Rehab: functional ambulation (sacral or LS lesion)

Prognosis

MR- 10-15%

Most deaths occur before age 4 years

70% have normal intelligence, but learning

problems and seizure disorders are common

History of meningitis or ventriculitis adversely

affect the ultimate IQ

Craniosynostosis

Definition

• Craniosynostosis refers to premature closure of

cranial sutures, or joints between the bones of the

skull

Trauma

History

• indian 30 years male pedestrian

• hit by a car in front of PSMMC

• brought to trauma room

• not opening eyes ,localising to painful stimuli,and

producing sounds

Main points in head injury

stratification of head injury and when to do CT

3 categories

CATEGORY 1.

LOW RISK FOR INTRACRANIAL INJURY

Extremely low likelihood of

intracranial injury

even if a skull fracture is

present on SXR (incidence

of ICI 8.5 in 10,000 cases

with 95% confidence level

this category excludes

patients with a history of

loss of consciousness.

CATEGORY2.

MODERATE RISK FOR INTRACRANIAL

INJURY

CATIGORY 3

HIGH RISK FOR INTRACRANIAL

INJURY

Intracranial pressure

indication for ICP monitoring

• 1- GCS 8/15 with an abnormal CT brain

• 2- GCS 8/15 with normal CT brain but 2 of below

• age over 40 ,SBP below 90mmHg,posturing

• 3- multiple system injuries with need for

PEEP,large amount fluid resuscitation

• 4- prolonged procedure e.g surgery

Monro kellie doctrine

Causes

1-Metabolic or collagen disease

2-Malignancy

3-Endo or exo-toxins

4-Ischaemia

5-Radiation * infection:leprosy

6-Trauma

a-Thermal

b-Chemical

c-Mechanical

Types of Injuries

primary injury

Results from same trauma that injures a bone or joint

Radial nerve is the most commonly injured. Of humeral

shaft fractures, 14 % is complicated by radial nerve

injuries

Displaced osseous fragments

Stretching

Manipulation

secondary injury

Results from involvement of nerve by infection, scar,

callous or vascular complications which may be

hematoma, AV fistula, Ischemia or aneurysm

Neuronal degeneration and regeneration

Any part of neuron detached from its nucleus

degenerates & is destroyed by phagocytosis.

Distal – Secondary / Wallerian Degeneration

Proximal - Primary / Traumatic / Retrograde

Degeneration

Time required for degeneration varies between sensory

and motor fibers and is also related to size &

myelination of fibers

Advancing Tinel sign and presence of motor march

phenomena are signs of regeneration

Diagnosis of Peripheral nerve injuries

History

Which nerve ?

What level ?

What is the cause ?

What degree of injury ?

Old or fresh injury ?

Diagnosis of Peripheral nerve injuries

Motor:

All muscles distal to the injury – paralyzed & atonic

Atrophy : 50 -70 % in 1st two months

Striations & motor end plate configurations retained for 12 – 18

months (critical limit of delay)

Sonsory :

Sensory loss follows a definite anatomical pattern, some overlap

from adjacent nerves may be present

Autonomous zone

Weber 2 point discrimination test

Tinel’s sign

Reflexes & Autonomic

Abolishes all reflexes transmitted by that nerve, either afferent or

efferent arc.

Complete & incomplete lesion. So , not a reliable guide to injury

severity.

Autonomic :

Loss of sweating

Loss of pilomotor response and

Vasomotor paralysis in autonomous zone

Others

Trophic ChangesEsp. hand and feet

Skin – thin, glistening,

breaks easily to form

ulcers that heal slowly

FingernailsRidged, distorted and

brittle

Osteoporosis (Reflex

sympathetic dystrophy)

BRACHIAL PLEXUS INJURIES

BRACHIAL PLEXUS INJURIES

etiology include:

1. penetrating trauma

2. traction (stretch injuries): more likely to affect the posterior and lateral cords

than the medial cord and median nerve

3. first rib fractures

4. compression by hematoma

Initial exam seeks to differentiate preganglionic injuries (proximal to dorsal root

ganglion) which cannot be repaired surgically, from postganglionic injuries.

preganglionic injury include:

1. Horner's syndrome: pre-ganglionic injury interrupts white rami

communicantes

2. paralysis of serratus anterior (long thoracic nerve): produces

winging of scapula

3. paralysis of rhomboids (dorsal scapular nerve)

4. early neuropathic pain suggests nerve root avulsion. MRI or

myelogram will show

pseudomeningoceles at the avulsed levels

5. EMG: requires ~ 3 weeks from injury for some findings. Look for:

A.denervation potentials in paraspinal muscles due to loss of neural

input. The posterior ramus of the spinal nerve originates just distal

to the dorsal root ganglion. Due to overlap, cannot localize to a

specific segment

preganglionic injury include: 2

B. normal sensory nerve action potential (SNAP):

preganglionic injuries leave the dorsal ganglion sensory cell

body and the distal axon intact, so that normal

SNAP can be recorded proximally even in an anesthetic

region

6-pseudomeningocele on myelography or MRI: suggests

nerve root avulsion (very proximal)

(Duchene)-Erb's palsy

Upper brachial plexus injury (C5 & 6, some authors include C7) e.g.

from forceful separation of humeral head from shoulder, commonly

due to difficult parturition or motorcycle accident (downward force on

shoulder can cause traumatic nerve root avulsion from the spinal

cord).

Paralysis of deltoid, biceps, rhomboids, brachioradialis, supra- &

infra-spinatus, and occasionally supinator. C7 involvement produces

weak wrist extension.

Motor: arm hangs at side internally rotated & extended at elbow and

flexed at the wrist ("Bellhop's tip position"). Hand motion is

unaffected.

Mechanism of injury

Klumpke's palsy

Injury to lower brachial plexus (C8 & Tl, some authors include C7),

from traction of abducted arm e.g. in catching onesulf during a fall from a

height, or by Pancoast tumor

Characteristic claw deformity (also seen with ulnar nerve injury) with

weakness and wasting of small hand muscles. Possible Horner's

syndrome if T1 involved.

Mechanism of injury

MEDIAN NERVE ENTRAPMENT

Above the elbow, the median nerve may rarely be

compressed by Struther's ligament

At the elbow and forearm, the median nerve may rarely

be trapped at any of three sites:

1) lacertus fibrosus (bicipital aponeurosis)

2) pronator teres

3) sublimis bridge

STRUTHER'S LIGAMENT

Distinct from struthers arcade which is a normal finding

The supra condylar process (SCP) is an anatomical variant

located 5-7 cm above medial epicondyle

present in 0.7-2.7% of population.

Struther's ligament bridges the SCP to the medial epicondyle.

The median nerve and brachial artery pass underneath, the ulnar

nerve may also.

Usually asymptomatic, occasionally may cause typical median

nerve syndrome.

PRONATOR (TERES} SYNDROME

From direct trauma or repeated pronation with tight hand-grip

Trapped between 2 heads of pronator teres.

Causes vague aching and easy fatiguing of forearm muscles with weak grip

and poorly localized paresthesias in index finger and thumb

no Nocturnal exacerbations Pain in palm distinguishes this from carpal tunnel

syndrome (CTS) since the median palmar cutaneous branch (PCB) exits

before the TCL and is spared in CTS

Treat with resting forearm.

Surgical decompression indicated for cases that progress while on rest or

when continued trauma is unavoidable.

ANTERIOR INTEROSSEOUS NEUROPATHY

a purely motor branch of the median nerve that arises in the upper

forearm

produces no sensory loss and weakness of the 3 muscles supplied by

the nerve:

1. flexor digitorum profundus (FDP) I & II: flexion of distal phalanx of

digits 2 & 3

2. flexor pollicis longus (FPL): flexion of distal phalanx of thumb

3. pronator quadratus (in the distal forearm): difficult to isolate

clinically

CTS

Most common entrapment neuropathy

Median nerve compression by the transverse carpal lig

More women than men

Often bilat but almost without exception more prominent in

the dominant hand

Paresthesia usually in median nerve distribution

(thenar eminance spared as supplied by palmar cutaneous

sensory branch which comes off proximal to the carpal

tunnel

Advanced cases may have thenar muscle

weakness/wasting effecting thumb opposition and ab

Causes of CTS

Often idiopathic

Repeated stress to connective

tissue

Repetitive hand use

Individuals with small carpal

tunnel

Systemic disorders (RA,

hypothyroidism, DM, sarcoid,

amyloidosis

Mass in wrist (ganglion cyst,

neurofibroma, arteriovenous

malformation)

Pregnancy

Persistent wrist flex ie during

sleep

Examination

Phalan’s good specific (75-93%)

and moderate sensitive (64-

75%) for CTS

Tinel’s similar spec & sens (tetro

et al, 1995 Bolland et al, 2008)

Carpal compression test more

spec less sensitive

NCS and EMG can help confirm

diagnosis and discount others

(however can be normal in 25%

of cases)

Differential diagnosis

1-C6-7 radiculopathy

2-Bracial plexopathy

3-Proximal median neuropathyThese can be identified by pain in the neck, reduced

reflexes, weakness outside median nerve distribution,

sensory loss in the thenar eminence

Treatment

Remove causative factorsSplints (night)NSAIDsInjection may be particularly helpful during pregnancy or other reversible condition i.e. Hypothyroidism

Surgical decompression

Ulnar Nerve entrapment

Second most common PNE in upper limb

Caused by compression of ulnar nerve in

the ulnar groove or cubital tunnel

Results from repeated trauma,OA

following #, ganglion/tumours/fibrous

tissue

Manifests as progressive loss of grip and

pinch strength and interosseus muscle

function Clumsiness

Wasting of thenar and hypothenar

eminence

Clinical

Sensory loss 4th &5th fingers

Elbow pain spreading to wrist

Ulnar nerve may be palpable and

tender

Paresthesia provoked by tinel’s, ulnar

nerve compression or elbow flexion

Making a fist may result in 4th and 5th

finger not flexing (FDP innervated by

UN)

Several classic hand postures

may be present

1-Benediction posture

2-Wartenberg’s sign

3-Froment’s sign

Treatment

Conservative treatment

Avoid aggravating factors

Jt protection

Elbow splint

Surgical options

Transportation

Decompression cubital tunnel

Medial epicondylectomy

Many will recover spontaneously

but surgery very effective

90% of pt’s with mild symptoms

will recover with conservative Rx

Ulnar nerve compression at the wrist

Similar manifestation with weakness of

the hand intrinsics and thenar and

hypothenar eminences

Exacerbated by activities such as riding

bike or manual labour that repetitively

compresses ulnar side of the wrist and

Guyon’s canal

#, trauma, ganglion cysts, ulnar artery

thombus

Diagnosis and Treatment

May require MRI or CT

for diagnosis as well as

EMG and NCS

Conservative treatment

usually successful but

may require

decompression if mass

present

Radial Neuropathy at the Spiral Groove

Saturday night palsy

Presents with complete wrist

and finger drop

Numbness in the lat dorsum of

the hand

weak supination and elbow flex

Elbow ext normal

Finger abd should be

unaffected (must be tested in

neutral)

Triceps reflex normal

Brachioradialis reflex reduced

or absent

Radial nerve entrapment cause

Radial nerve lies in

juxtaposed to spiral

groove making it liable

to compression

Prolonged compression

leads to demylination

Can result from #

humerus, vasculitis or

stenuous muscle effort

Peroneal Neuropathy at the Fibular Head

Usually involves both deep and

superficial peroneal nerves

Therefore weakness in ankle df

and eversion

Sensory loss over dorsum of the

foot and lat calf

May be pain and Tinel’s over fib

neck

Ankle inversion spared as

innervated by Tib nerve.

Causes

Habitual leg crossing

Repetitive stretch from

squatting

Thin pt’s

Ganglions cyst

Associated to ankle

inversion injury including #

fib

Traction to nerve

Prolonged immobilisation

(especially sedated pt’s)

Treatment

local injected

AFO

Stretches to prevent contractures

Gait rehab

Proprioceptive work

Eliminate offending activities ie leg

crossing

Surgery rarely needed except

where extensive nerve damage

or mass present