nurosurgery pdf - د.سيف انمار

Neurosurgical investigations

Cerebrospinal fluid (CSF) examination

1. Spinal : lumber puncture LP aspirating CSF from lumbar cistern (L4-5/L3-4)
2. Cranial : lateral ventricular puncture

LP indicated in :

1.  suspected meningitis
2.  subarachnoid hemorrhage SAH
3.  neurological diseases like Gullaine Barre Syndrome GBS and multiple sclerosis MS
4.  cytology in neoplastic diseases
5.  measurement of intracranial pressure
6.  therapeutic CSF aspiration  (benign raised intracranial pressure)(pseudotumor cerebri).
7.  contrast injection in conventional myelography
8.  intraspinal injection of anesthetic drugs in spinal anesthesia

LP is contraindicated in

1. raised intracranial pressure other than pseudotumor cerebri . e.g. brain tumors ,

obstructive hydrocephalus and brain abscess and cyst. Features suggestive include focal
neurological deficit and recent seizure and papilloedema.

2.  Local sepsis at the site of LP
3.  Bleeding tendency
4.  Abnormal respiration i.e. moribund patient
5.  Vertebral deformities ( kyphosis and scoliosis ).

Complications of LP



Post spinal headache with nausea is the most common complication; it often

responds to analgesics and infusion of fluids and maintaining supine posture



Cerebellar tonsillar herniation if there is raised ICP.



Injury to the neural structure



Back pain



Local infection and meningitis



Implantation of cutaneous tissue with subsequent epidermoid cyst



Bleeding

Imaging Studies

Skull x-ray may reveal

it can reveal



Skull fractures



Hyper stosis as in meningioma



Bone erusion tumors



Abnormal calcification as in meningioma , craniopharyngioma and calcified cyst or

aneurysm



Lateral displacement of calcified pineal body by a neoplasm



Features of long standing raised ICP

  Erusion of the sella torcica clinoids
  Double floor sella torsica
  Beaten copper appearance

 Suture diastasis

Spinal x-ray

1. Vertebral alignment.
2. Presence of degenerative disease with narrowing of the neural foramina and spinal

canal.

3.  Evidence of metastatic tumor with erosion or sclerosis of the vertebra
4.  Enlargement of a neural foramen indicating a spinal schwannoma.
5.  Congenital abnormalities such as spina bifida.

Computerised tomography CT scanning

Non invasive test , useful in evaluating patient with head injury and stroke
Contrast study can be used but it carry risk of pain, nausea, thermal sensation, bronchospasm
and anaphylaxis.
So useful in stroke because it clearly differentiate hemorrhage from ischemia, also in head
injuries by showing fractures , hematomas and brain oedema and pathology.
in cases of brain neoplasm can identify it with its surrounding oedema and associated midline
shift and whether solid or cystic and if any associated hydrocephalus or brain abscess

Magnetic resonance imaging (MRI)

The patient lies within a magnetic field that aligns some protons along with magnetic axis. The
protons resonate when stimulated with radiofrequency energy producing strong echo enough to
be detected and recorded .the signal intensity depend on concentration of mobile hydrogen nuclei
of the tissue. In comparison to CT,



MRI is better for evaluating posterior fossa and lesions of multiple sclerosis



it is free from bone artifact with primary multi plane imaging ( axial, sagittal and

coronal)



High resolution for spinal cord together with non invasive MR myelography.



It involve no radiation so it can be repeated as necessary



Can detect ischemic areas few hours from the onset unlike CT that may require 48 hr

Contraindications include

1.  Metalic foreign bodies e.g. Intracranial clips, cochlear implants, pace maker…etc
2.  Claustrophobia
3.  Gross obesity
4.  Uncontrolled movement, Parkinsonism
5.  Respiratory diseases RDS requiring ventilation or carry risk of apnea

Indications for Magnetic Resonance Imaging are:

1.  IntracranialSOL .like Glioma and Meningioma and Hydatid cyst
2.  CNS infection—cerebral abscess
3.  Arteriovenous malformations.AVM
4.  Venous sinus thrombosis.
5.  Craniospinal abnormalities such as the Chiari malformation.
6.  Syringomyelia.
7.  Spinal tumours.
8.  Disc prolapse (including cervical, lumbar and dorsal disc prolapse).
9.  Spinal canal stenosis (lumbar or cervical stenosis) and cervical myelopathy.

Cerebral and spinal angiography

images of blood vessels in and around the brain,

AVM

and aneurysms.

Myelography

Conventional myelography(invasive)

CT myelography(invasive)

MR myelography (non invasive)

Positron emission tomography PET



(PET) scan is an imaging test that can map tissue biochemistry and physiology.



The most commonly used PET tracer being a labeled form of glucose ( Fludeoxyglucose

(18F) (FDG). Useful in differentiating ischemic from neoplastic areas.

MR spectroscopy

(MRS) is a non-invasive, ionizing radiation free analytical technique used to study metabolic
changes in brain tumors, strokes, seizure disorders.

MR tractography
Visual representation of neural tracts

Neurophysiological studies
1) Electroencephalography (EEG)

records the spontaneous electrical activity of the brain through scalp electrodes
The main indication



Diagnosis and follow up of epileptic patients



sleep disorders

coma

encephalopathies



To differentiate

epileptic

seizures

from

psychogenic non-epileptic seizures



characterize seizures

for the purposes of treatment



to localize the region of brain from which a seizure originates for work-up of

possible seizure surgery

waves pattern :

1. delta wave: is the frequency range up to 4 Hz.It is seen normally in adults in

slow

wave sleep

. It is also seen normally in babies.

Theta

is the frequency range from 4-7 Hz. Theta is seen normally in young

children and

meditation

Alpha

is the frequency range from 7

14 Hz. It emerges with closing of the eyes

and with relaxation, and attenuates with eye opening or mental exertion.

Alpha can be abnormal; for example, an EEG that has diffuse alpha occurring in
coma and is not responsive to external stimuli is referred to as "alpha coma"