Diagnostic Technique In Neurosurgery PDF

DIAGNOSTIC TECHNIQUE IN NEUROSURGERY MORGAN BABCOCK Outline u Introduction u Properties of a diagnostic tool in neurosurgery u Classification u Specific investigations u conclusion Introduction u Diagnostic technique in neurosurgical practices has advanced wi...

DIAGNOSTIC TECHNIQUE IN NEUROSURGERY MORGAN BABCOCK Outline u Introduction u Properties of a diagnostic tool in neurosurgery u Classification u Specific investigations u conclusion Introduction u Diagnostic technique in neurosurgical practices has advanced with technological breakthrough around the world u These are set of test carried out to either screen, confirm diagnosis and help in formulating treatment procedure u It does not replace good clinical acumen contd u Diagnosis involves a tripod of  History  Examination  Investigation Property u Easy to use u Non harmful u Non-carcinogenic u Non-allergic u Must be 100% sensitive u Must be 100% specific u No Ideal radiological tool Classification u Radiological  Plain X-ray,  ultrasound scan,  computed tomography scan,  magnetic resonance imaging,  positron emission tomography,  radionuclide study u Non-radiological  Cerebrospinal fluid analysis,  hormonal assay,  tumour markers,  nerve conduction studies Plain X-ray u It is a common investigation u Plain X-rays are useful to identify fracture, dislocation, deformity, infection u Skull and spine X-ray are often requested u Plain X-ray Skull X-ray: AP and lateral view B. Plain X-rays of the spine: X-rays of cervical spines X- ray of thoracic (dorsal) spines X-ray of the lumbosacral spines Open Mouth View for C1&C2 spine u Plain X-rays of the spine Particular note should be taken of: Vertebral alignment. Presence of degenerative disease with narrowing of the neural foramina and spinal canal. Evidence of metastatic tumour with erosion or sclerosis of the vertebral body, pedicles or lamina. Enlargement of a neural foramen indicating a spinal schwannoma. Congenital abnormalities such as spina bifida. u The major abnormalities to look for on a skull X-ray are: Fractures linear and depressed u Hyperostosis, e.g. meningioma. u Bone erosion due to skull vault tumours. u Abnormal calcification, e.g. tumours such as meningioma, oligodendroglioma, craniopharyngioma or calcified wall of an aneurysm. u Signs of long-standing raised intracranial pressure erosion of the dorsum sellae, Double floor sella turcica copper beating appearance of the skull vault. u Computed Tomography (CT)Scan Indications for Computed Tomography in Neurosurgery: Cranial CT: Diagnosis of acute neurosurgical lesions in the head and spine, including: Skull and spinal fractures. u Intracranial hemorrhage: like extradural haematoma, subdural haematoma, intracerebral haematoma. u Oedema: brain oedema whether due to trauma or other cause. u Mass lesions: mainly brain mass lesions like tumours and brain abscess. u Hydrocephalus u Stroke: differentiate between infarction and intracranial haemorrhage. u CT is better than MRI Diagnoses of bone related pathologies like fractures and bone tumours. Better for acute hemorrhagic lesions, Less time is needed to perform CT than MRI (few minutes) critically ill patients. u MRI is better than CT in Sellar pathology (pituitary), Posterior fossa tumours (cerebellar and brain stem tumours). Spinal cord pathology (compression and tumours), and one can do myelography with non invasive method (no need for lumbar puncture). u Infarction can be diagnosed as early as few hours whereas CT needs 48 hours to diagnose it. No ionizing radiation. Can be repeated safely u Contraindications to MRI Metallic foreign bodies anywhere in the body like plating and screwing, shells ,cardiac pace maker, intracranial clips Claustrophobia. Gross obesity, Uncontrolled movement disorders (Parkinson’s disease). Respiratory disease that require assisted ventilation or carry risk of apnea CT Scan showing communited fracture of the skull Indications for Magnetic Resonance Imaging  Intracranial tumours.  cerebral abscess.  Arteriovenous malformations.  Venous sinus thrombosis.  Craniospinal abnormalities such as the Chiari malformation.  Syringomyelia.  Spinal tumours.  Disc prolapse (including cervical, lumbar and dorsal disc prolapse).  Spinal canal stenosis (lumbar or cervical stenosis) and cervical myelopathy. positron emission tomography PET u A positron emission tomography (PET) scan is an imaging test that can map tissue biochemistry and physiology i.e functional test The most commonly used PET tracer being a labeled form of glucose ( Fludeoxyglucose (18F) (FDG). Useful in differentiating ischemic from neoplastic areas. u Cranial and Spinal Angiography images of blood vessels … u arteriovenous malformations u Intracranial aneurysms Ultrasound scan(USS) u Tranfontanelle USS Hydrocephalus Intracranial bleed u Doppler scan Carotid study Ultrasound scan is simple, faster, non radiation but observer dependent Non radiological u Cerebrospinal fluid(CSF) investigation It can be obtained by Spinal : lumbar puncture LP Cranial : lateral ventricular puncture fluid can be accessed most safely in the lumbar cistern, where the spinal cord has terminated into the cauda equina (between the level of the first and second lumbar vertebrae. The lumbar cistern extends into the sacrum. u Lumbar Puncture u Lumbar Puncture Indications suspected meningitis subarachnoid hemorrhage SAH cytology in neoplastic diseases measurement of intracranial pressure ICP therapeutic CSF aspiration (benign raised intracranial pressure)(pseudotumor cerebri). conventional myelography by contrast injection Spinal anesthesia u Measurement of intracranial pressure u Contraindications to Lumbar Puncture raised intracranial pressure other than pseudotumor cerebri. Features suggestive of raised ICP are focal neurological deficit recent seizure papilloedema. Sepsis at the site of LP Bleeding tendency like coagulopathy and thrombocytopenia less than 50 × 109 /L Abnormal respiration i.e. moribund patient Vertebral deformities ( kyphosis and scoliosis ) , total spinal block, obstructive hydrocephalus u Complications of lumbar puncture Post spinal headache triad treatment Cerebellar tonsillar herniation if there is raised ICP. Injury to the neural structure Back pain infection and meningitis Implantation of cutaneous tissue with subsequent epidermoid cyst Bleeding Hormonal studies u Sellar and parasellar pathologies Pituitary tumours Craniopharygioma Tuberculum sellar meningioma u Prolactin u ACTH u Cortisol u TSH, T3,T4 u GH Tumour markers u In pineal region tumours Beta- HCG Alpha fetoprotein Placental alkaline phosphatase Conclusion u Diagnostic tests form an important bedrock in the management of patients in neurosurgery u A tripod of history, examination and investigation is essential in making a diagnosis