Arab Board Neurosurgery Final Clinical & Oral cheat sheet

Corticospinal fibers decussate at the medullary pyramids; thus a lesion above the decussation causes contralateral paresis, below it causes ipsilateral paresis.

Ulnar nerve supplies intrinsic hand muscles except the two radial lumbricals and thenar muscles (median); claw hand pattern follows this split.

Oculomotor nerve carries parasympathetic fibers from the Edinger-Westphal nucleus; a fixed dilated pupil with ptosis suggests compressive CN III lesion.

Broca area (dominant inferior frontal gyrus) lesion gives nonfluent speech with preserved comprehension; Wernicke area lesion gives fluent speech without comprehension.

The anterior choroidal artery supplies the posterior limb of the internal capsule, globus pallidus, and optic tract; occlusion causes hemiparesis, hemianopia, and hemisensory loss.

Cerebrospinal fluid production is roughly 500 mL/day, with total volume about 150 mL in adults; this turnover underlies shunt flow requirements.

The lateral corticospinal tract is somatotopically organized with cervical fibers medial and sacral fibers lateral.

Upper motor neuron signs include spasticity, hyperreflexia, and Babinski sign; lower motor neuron signs include atrophy, fasciculations, and areflexia.

CT detects acute hemorrhage immediately; ischemic infarction may be invisible on CT for 6-12 hours, making MRI diffusion-weighted imaging the early gold standard.

Hyperdense middle cerebral artery sign on noncontrast CT indicates intraluminal thrombus and correlates with large-vessel occlusion.

CT angiography with a 6-hour window guides mechanical thrombectomy decisions; perfusion imaging extends eligibility in selected patients.

Suspected spinal cord compression requires urgent MRI with gadolinium; CT myelography is reserved for MRI-incompatible patients.

Cerebral aneurysms are screened with CTA and confirmed with digital subtraction angiography, which remains the reference standard for treatment planning.

Gadolinium enhancement indicates blood-brain barrier disruption; ring enhancement with central necrosis suggests high-grade glioma or abscess.

Skull base lesions benefit from thin-slice CT for bone erosion and MRI for soft tissue and perineural spread.

Xanthochromia in cerebrospinal fluid analyzed by spectrophotometry supports subarachnoid hemorrhage when CT is negative after 6 hours.

The Glasgow Coma Scale ranges 3-15; severe traumatic brain injury is GCS 3-8 and warrants airway protection and intracranial pressure monitoring consideration.

The Monro-Kellie doctrine states that brain, blood, and cerebrospinal fluid volumes are constant; expansion of one compartment raises intracranial pressure.

Epidural hematoma results from middle meningeal artery injury, appears biconvex on CT, and may have a lucid interval; subdural hematoma is crescentic from bridging vein tearing.

Pupillary dilation with bradycardia and hypertension (Cushing triad) signals impending herniation requiring urgent decompression.

Extradural spinal cord compression from trauma is managed with immobilization and early decompression; methylprednisolone is not recommended as routine therapy.

The Canadian CT Head Rule and New Orleans Criteria stratify minor head injury for imaging; age over 65 and anticoagulation lower the imaging threshold.

Diffuse axonal injury shows punctate hemorrhages at grey-white junctions on MRI susceptibility-weighted imaging and carries poor prognosis with low GCS.

Basilar skull fracture signs include hemotympanum, periorbital ecchymosis, and cerebrospinal fluid rhinorrhea; prophylactic antibiotics are not indicated.

Glioblastoma (WHO grade 4) shows ring enhancement with central necrosis and is treated with maximal safe resection followed by temozolomide chemoradiation.

Meningiomas are typically extra-axial, dural-based, enhance homogeneously, and may show a dural tail; WHO grade predicts recurrence.

Pituitary adenomas causing visual field deficit typically compress the optic chiasm superiorly, producing bitemporal hemianopia.

Metastatic brain tumors are the most common intracranial tumors in adults; management depends on number, size, and systemic disease control.

Spinal metastases most often involve the vertebral body and epidural space; cord compression requires urgent corticosteroids and surgical or radiation assessment.

Ependymomas arise from ependymal lining, show periventricular location, and can seed cerebrospinal fluid; craniospinal imaging is required.

Medulloblastoma in children arises in the cerebellar vermis and may present with hydrocephalus and ataxia; it carries a risk of neuraxis dissemination.

Low-grade gliomas (IDH-mutant, 1p/19q codeleted) have better prognosis and greater chemosensitivity than IDH-wildtype tumors.

Aneurysmal subarachnoid hemorrhage presents with thunderclap headache; CT within 6 hours has near-100% sensitivity, and lumbar puncture with xanthochromia is used later.

The Hunt and Hess and World Federation of Neurosurgical Societies scales grade subarachnoid hemorrhage severity and correlate with outcome.

Nimodipine 60 mg every 4 hours for 21 days reduces delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.

Aneurysm treatment options are endovascular coiling or surgical clipping; anterior communicating and middle cerebral artery aneurysms are common surgical targets.

Arteriovenous malformations are graded by the Spetzler-Martin system using size, eloquence of location, and venous drainage pattern.

Moyamoya disease shows progressive stenosis of distal internal carotid arteries with collateral puff-of-smoke vessels; revascularization is the main treatment.

Decompressive hemicraniectomy within 48 hours improves survival in malignant middle cerebral artery infarction in selected patients under 60 years.

Cerebral vasospasm typically occurs 3-14 days after subarachnoid hemorrhage and is monitored with transcranial Doppler and angiography.

Cauda equina syndrome presents with saddle anesthesia, bowel or bladder dysfunction, and bilateral leg symptoms; it is a surgical emergency requiring urgent decompression.

Cervical spondylotic myelopathy shows hyperreflexia, gait disturbance, and hand clumsiness; MRI confirms cord compression and signal change.

Lumbar disc herniation most often affects the L5 root at L4-L5 and the S1 root at L5-S1 due to posterolateral anatomy.

Spinal epidural abscess presents with fever, back pain, and neurologic deficit; urgent MRI and surgical drainage with antibiotics are indicated.

Spondylodiscitis commonly involves the vertebral body and disc space; Staphylococcus aureus is the most frequent pathogen.

Thoracolumbar fractures are classified by the AO Spine system; neurologic deficit and posterior ligamentous complex injury drive operative decisions.

Osteoporotic vertebral compression fractures may be treated with vertebroplasty or kyphoplasty when conservative management fails.

Cervical facet dislocation requires reduction and stabilization; MRI before reduction is considered when disc herniation is suspected.

Congenital hydrocephalus is managed with ventriculoperitoneal shunt or endoscopic third ventriculostomy; shunt malfunction presents with headache, vomiting, and lethargy.

Chiari II malformation is associated with myelomeningocele and presents with hindbrain herniation and hydrocephalus.

Myelomeningocele requires early closure; prenatal repair reduces shunt dependence and improves motor outcomes.

Dandy-Walker malformation involves cerebellar vermis hypoplasia and cystic dilation of the fourth ventricle with hydrocephalus.

Craniosynostosis is assessed clinically and with CT; surgical timing depends on suture involvement and risk of raised intracranial pressure.

Pediatric brain tumors differ from adults: medulloblastoma and pilocytic astrocytoma are common, while glioblastoma is less frequent.

Tethered cord syndrome presents with progressive leg weakness, sphincter dysfunction, and back pain; MRI confirms conus position below L2.

Arachnoid cysts may be incidental or cause hydrocephalus and mass effect; symptomatic cysts may require fenestration or shunting.

Deep brain stimulation of the subthalamic nucleus or globus pallidus interna improves motor symptoms of Parkinson disease and reduces medication fluctuations.

Essential tremor responds to thalamic (ventral intermediate nucleus) deep brain stimulation or thalamotomy.

Trigeminal neuralgia is treated with carbamazepine first-line; microvascular decompression is effective when vascular compression is demonstrated.

Anterior temporal lobectomy is the most common epilepsy surgery and yields good seizure freedom in mesial temporal sclerosis.

Vagus nerve stimulation reduces seizure frequency and is an option for medically refractory epilepsy not amenable to resection.

Stereotactic radiosurgery is used for trigeminal neuralgia, arteriovenous malformations, and small tumors; it requires precise imaging-based targeting.

Epilepsy surgery evaluation includes MRI, video-electroencephalography, and neuropsychological assessment; invasive monitoring is used when noninvasive data conflict.

Intrathecal baclofen and dorsal column stimulation are options for spasticity and chronic pain, respectively.

Brachial plexus injuries are classified as preganglionic (root avulsion) or postganglionic; preganglionic injuries require nerve transfer rather than grafting.

Erb palsy involves C5-C6 roots and presents with weakness of shoulder abduction and elbow flexion; Klumpke palsy involves C8-T1 and causes hand weakness.

Median nerve injury at the wrist causes thenar wasting and loss of thumb opposition; ulnar nerve injury causes claw hand and Froment sign.

Nerve repair options include primary repair, nerve grafting, and nerve transfer; timing and gap length determine the choice.

Carpal tunnel syndrome is confirmed by nerve conduction studies; surgical release divides the transverse carpal ligament.

Peripheral nerve sheath tumors present as painful masses; schwannomas are usually benign and surgically excisable.

Radial nerve injury at the humerus causes wrist drop; recovery is often favorable with observation.

Facial nerve palsy is assessed with House-Brackmann grading; surgical decompression or grafting is considered in severe cases.

Vestibular schwannoma presents with sensorineural hearing loss and tinnitus; MRI with gadolinium shows an enhancing cerebellopontine angle mass.

Pituitary apoplexy is an endocrine emergency with headache, visual loss, and ophthalmoplegia; urgent transsphenoidal decompression is indicated.

Cerebrospinal fluid rhinorrhea from skull base defects may require endoscopic repair; beta-2 transferrin confirms cerebrospinal fluid.

Cranial nerve III palsy with a fixed dilated pupil suggests compression, often by posterior communicating artery aneurysm.

Cavernous sinus lesions may involve multiple cranial nerves (III, IV, V1, V2, VI) and require MRI and angiography for assessment.

Olfactory groove meningiomas cause anosmia and frontal lobe symptoms; surgical resection is the treatment of choice.

Jugular foramen tumors (glomus tumors, schwannomas) present with lower cranial nerve deficits and require angiography for vascular assessment.

Endoscopic endonasal approaches are used for sellar and parasellar lesions; cerebrospinal fluid leak repair is a key perioperative concern.

Intracranial pressure monitoring is considered in severe traumatic brain injury with GCS 3-8 and abnormal CT; treatment threshold is often 20-22 mmHg.

Hyperosmolar therapy with mannitol or hypertonic saline reduces intracranial pressure; serum osmolality and renal function are monitored.

Targeted temperature management may be used after cardiac arrest; fever should be avoided in neurocritical patients.

Seizure prophylaxis with levetiracetam or phenytoin is common after severe traumatic brain injury or neurosurgery for 7 days.

Venous thromboembolism prophylaxis with mechanical methods is used early; pharmacologic prophylaxis is delayed after intracranial surgery or hemorrhage.

Sodium and glucose abnormalities are common after neurosurgery; hyponatremia may reflect syndrome of inappropriate antidiuretic hormone or cerebral salt wasting.

Perioperative steroids reduce edema around brain tumors; they are not routine in traumatic brain injury.

Anticoagulation reversal in intracranial hemorrhage includes vitamin K, prothrombin complex concentrate, and platelet transfusion as indicated.

Informed consent requires disclosure of diagnosis, proposed treatment, alternatives, risks, and benefits, and confirmation of patient understanding.

Capacity assessment requires understanding, appreciation, reasoning, and expression of choice; it is decision-specific.

Emergency exception allows treatment without consent when delay would risk serious harm and no surrogate is available.

Surgeon fatigue and handoff errors are patient-safety risks; structured handoffs and time-outs reduce adverse events.

Conflict of interest and financial relationships must be disclosed; they can compromise clinical judgment and patient trust.

End-of-life discussions should address goals of care and advance directives early in serious illness.

Confidentiality is protected except where disclosure is required by law or necessary to prevent serious harm.

Second opinions and multidisciplinary tumor boards improve decision quality and should be documented in the record.