Hydrocephalus And Shunts

Abdominal ultrasound examination, looking for encysted collections of CSF, may be useful in such cases (see above). Blood cultures are frequently unhelpful in diagnosing VP shunt infection however, measurement of C-reactive protein (CRP) can be a useful guide, both as part of the initial investigation and as a means of monitoring the effectiveness of treatment. Organisms Responsible for Shunt Infection The commensal skin flora is the usual source of pathogens that give rise to shunt...

Ischemic Stroke And Carotid Endarterectomy

Under the sternocleidomastoid, the internal jugular vein and the common facial vein, a branch of the internal jugular, are identified, double-ligated and divided. Care should be taken not to injure the spinal accessory nerve, which is at risk for transection and stretching. Gentle lateral retraction of the internal jugular exposes the carotid artery. Opening the carotid sheath then proceeds, starting inferiorly by the anterior surface of the artery to the level of the omohyoid muscle....

Anterior Craniofacial Resection

Anterior CFR encompasses structures of the anterior mid-line and paramedian skull base (see Fig. 15.4). The ethmoid sinuses superiorly, the anterior wall of the sphenoid posteriorly, the frontal sinus anteriorly, and the nasopharynx inferiorly are included in the surgical perimeter of the anterior craniofacial resection. Resection of malignant tumors of the paranasal sinuses involving the ethmoid frontal sinus with proximity to or involvement of the ethmoid roof cribriform plate. Resection of...

Risk Factors for Ischemic Stroke

Ischemic stroke can occur in people of all ages, at any time and without predilection for sex or race. Age, however, is the most important determinant of stroke, with most strokes occurring in individuals older than 65. Atherosclerosis affecting the extracranial and intracranial circulation differs according to race and ethnic group. For example, extracranial atherosclerotic lesions are more common in whites, while intracranial lesions are more common in blacks, Hispanics and Asians. Several...

Anterior Sacral Meningocele

An out-pouching of dura containing CSF may occur through a defect in the body of the sacrum (anterior spina bifida). This may be an isolated defect or may be in association with a more severe developmental abnormality of the whole caudal region of the embryo, as in caudal agenesis, where abnormalities of the genitourinary tract, rectum and anus may also occur in association with sacral agenesis. Presumably, the defect in the bone is the primary abnormality and, with the pressure of CSF, the...

Anatomy of the Peripheral Nervous System

The peripheral nervous system consists of those structures containing nerve fibers or axons that connect the CNS to motor, sensory, somatic and visceral end organs. This includes the cranial nerves (III-XII), spinal nerves, cervical, brachial and lumbosacral plexus and nerves of the extremity. These nerves are mostly mixed nerves (motor and sensory). In the peripheral nervous system, excluding the cranial nerves, they have their origin as a spinal nerve that is formed by the union of ventral...

Kleeblattschadel Anomaly

The word Kleeblattschadel is German for cloverleaf and describes the most severe form of craniosynostosis. It consists of a trilobular-shaped skull (Fig. 26.6), with synostosis of multiple sutures, which most commonly involves the cranial base, facial and cranial vault sutures, with the sagittal, squamosal and metopic remaining open, leading to compensatory bulging through them. The degree of severity varies with the involvement of the different sutures. There can also be a complete cranial...

Patient Evaluation

Pre-operative evaluation of patients with possible brain lesions requires a careful history and physical examination (including an accurate assessment of the patient's KPS) followed by radiological evaluation. The duration of pre-operative symptoms varies greatly, because some patients have harbored lower grade gliomas that have undergone malignant transformation, leading to longer histories than those with HGGs that arise de novo. Patients with HGG often present with headache (approx-imately35...

Benign Tumors of the Spinal Column

Benign tumors of the axial skeleton are most commonly found in children and adolescents. When they occur in adults, they are generally found in individuals between 20 and 30 years of age, in a posterior location. The more common types of benign lesions - osteochondroma, osteoid osteoma and osteoblastoma - have a lower incidence of recurrence if a complete excision can be obtained. Unlike malignant tumors that require resection of a wide margin of normal tissue surrounding the lesion, resection...

Wilsons Disease WD

WD is an autosomal-recessive disorder of copper metabolism. The term hepatolenticular degeneration is also used, as it affects the liver and causes movement disorders related to changes in the basal ganglia. The primary problem is a defect in copper metabolism, causing its build-up in the liver, brain and eye. Numerous cognitive, psychiatric and movement disorders may be seen with this disease. The neurologic manifestations include tremor (typically, a proximal or wing beating tremor),...

Neurosurgery

No correlation was found between rCBF measurements and neurological morbidity or overall complication rate. A second method of measuring CBF relies on near-infrared spectroscopy to assess cerebral oxygenation status. Also known as cerebral oximetry, this technique measures changes in the levels of oxygenated, deoxygenated and total hemoglobin as well as oxidized cytochrome in the local cerebral blood supply. The advantage of using the near-infrared spectrum is that...

Syndromic Craniosynostosis

The sella is enlarged and the greater wings of the sphenoid are protruded. There is an expanded ethmoidal labyrinth, with orbital hypertelorism and shallow orbits, with proptosis. Down-slanting palpebral fissures and strabismus are frequently present. The ocular motility disturbances may be due to mechanical factors or structural alterations of the extraoc-cular muscles. Mid-face hypoplasia is also characteristic of this syndrome, resulting in a depressed nasal bridge,...

Anesthesia for Biopsy or

The anesthetic must be chosen to lower ICP and minimize seizure risk (especially during cortical stimulation mapping). The patient's hepatic, renal and cardiopulmonary status will also impact on the anesthetic chosen . Volatile anesthetics are highly halogenated molecules with an unknown mechanism of action. The group includes halothane, enflu-rane, isoflurane, desflurane and sevoflurane. Halogenated anesthetics provide amnesia, analgesia, and muscle relaxation at higher dosage. The newer...

Actinomycosis and Nocardiosis

Actinomycosis is most commonly caused by Actinomyces israelii, an atypical Gram-positive anaerobic bacterium that exists as part of the normal oral and intestinal flora in man. It is not an opportunistic pathogen, but needs devitalized tissue for the anaerobic milieu required to support its growth and, to this end, often coexists with a commensal bacterial infection 24 . Actinomycosis occurs following a break in the mucosal barrier and produces a chronic suppu-rative granulomatous infection,...

Reduction of Brain Mass

Because of the presence of the blood-brain barrier, which is relatively impermeable to sodium and chloride ions, the movement of water into and out of the brain cells is primarily determined by the osmotic gradient. An effective osmotic diuretic that is frequently used to treat elevated ICP is 20 mannitol. Given as a bolus at 0.5-1.0 g kg, the action is immediate in onset, but peaks at 30 minutes, lasting for about 90 minutes. The loop diuretic, furose-mide, potentiates the actions of mannitol,...

Transcutaneous Electrical Nerve Stimulation TENS

TENS consists of a pulse generator or stimulator attached to the patient via Ap-fibers to modulate onward pain transmission in the spinal cord. The pulse generator has controls for frequency (2-250 Hz), pulse width and for selecting the type of TENS required. The main variants of TENS are Continuous. This is a continuous high-frequency low-intensity stimulation. Patients should experience a strong but comfortable sensation, akin to non-painful paresthesiae in the affected area. Pulsed. This...

Positron Emission Tomography

Positron emission tomography (PET) uses ISOlabeled carbon dioxide, carbon monoxide and oxygen to obtain quantitative maps of CBF, cerebral blood volume, oxygen extraction fraction and cerebral metabolic rate. PET has been used extensively in experimental studies of stroke, to define the ischemic penumbra and the effects of early reperfusion hyperperfusion. Clinical uses are less common. Recently, a study of patients with carotid occlusion demonstrated that patients with high oxygen extraction...

Monitoring of Cerebral Oxygenation Metabolism

Jugular Venous Oximetry, Tissue PO2, and Near-infrared Spectroscopy As cerebral ischemia and secondary injury are the common factors leading to deterioration, monitoring of some indices of cerebral oxygenation would provide guide to appropriate therapy. By placing a fiberoptic oximetric catheter into the jugular bulb, cerebral venous oxygenation can be monitored continuously, providing an index of the balance between cerebral blood flow (supply) and cerebral metabolic consumption of oxygen...

Degenerative Disease Of The Cervical Spine

The DOC plate (Johnson and Johnson Depuy-Acromed Incorporated, Cleveland, Ohio, USA). Anterior views of two DOC plates. The DOC plate is a dynamic device which compensates for subsidence across the fusion segment. The plate on the left demonstrates the upper crosslink device, which attaches to the vertebral bodies in the upright position. On the right, the upper crosslink has migrated inferiorly to the limiting crosslink, which is the amount of the subsidence allowed by this plate....

Candidiasis

Candida albicans is an opportunistic pathogen that rarely causes disease in healthy individuals, but becomes pathogenic when host defense systems become compromised or when the organism can accumulate in large numbers, such as during prolonged antibiotic therapy. CNS disease usually results from hematogenous dissemination and, less frequently, through direct invasion 24 . An extracranial focus of candidi-asis is present in over 70 of patients with documented meningitis. Approximately 50 of...

Benign Extracranial Skull Base Tumors

Highly vascular and locally invasive, juvenile angiofibromas occur almost exclusively in adolescent males. Although morphologically benign, these tumors can exhibit aggressive local growth, extending along planes of least resistance or pre-formed pathways and, when large, can invade directly by bone erosion. Juvenile angiofibromas represent less than 0.05 of all head and neck tumors, with a median age at presentation of around 13 years. It is thought the hormonal changes at puberty are the...

Terminology Used in Describing Movement Disorders

The term movement disorder is used in two contexts as a physical sign of involuntary movement or abnormal movement and to describe the syndrome that causes the involuntary movement 1 . In order to be able to discuss the different movement disorder syndromes, it is first imperative to define the types of movements that exist. This enables a common language among practitioners. Tremor is defined as a rhythmic oscillation of a body part by alternating or synchronous contraction of agonist and...

Arteriovenous Malformations

Case 4 A 65-year-old female presented with sudden headache, confusion and trace right-sided weakness. a An urgent axial head CT scan revealed a left-sided parietal hyperdensity. b An axial T1-weighted non-contrast MRI through the area of abnormality revealed a 2-cm cavernous malformation with areas of hemorrhage of various chronicity. An acute intraparenchymal bleed was noted anterior to the lesion. The woman was brought to the operating room and the lesion was removed. c A...

Internal Decompression and Extracapsular Dissection

Although small meningiomas may be removed en bloc, internal decompression is a key initial step in actual tumor removal for most meningiomas following adequate exposure and initial devascularization. Internal debulking is carried out until a thin rim of exposed portion of the tumor is remaining. This internal debulk-ing minimizes brain retraction and facilitates extracapsular dissection. Following initial internal decompression, extracapsular dissection is initiated by identifying a layer of...

References

Three types of nerve injury. Brain 1943 66 237-88. 2. Mackinnon SE, Dellon AL. Nerve repair and nerve grafts. In Surgery of the peripheral nerve. New York Thieme, 1988 89-129. 3. Sunderland S. Nerves and nerve injuries. 2nd Edition. New York Churchill Livingstone, 1978. 4. Kline DG, Hudson AR. Surgical repair of acute peripheral nerve injuries timing and technique. In Morley, editor. Controversies in neurosurgery. Philadelphia W.B. Saunders Co., 1976 184-97. 5. Kline DG, Hudson AR....

Occipital Condyle Fractures

First described by Bell in 1817, these are extremely uncommon 14 . The conscious patient may complain of occipito-cervical or neck pain, or may have lower cranial nerve palsies. These injuries are difficult to identify with plain radiographs and require a high index of suspicion. A retropharyngeal hematoma could be the only sign of serious injury. CT with reconstructions provides the definitive diagnosis. The classification of Anderson and Monte-sano is the most widely used and divides these...

Clinical Presentation

The clinical presentation of patients with CAVMs depends in large part on pathology and location of the lesion. Venous malformations are most commonly found incidentally. Rarely, a cerebellar venous malformation may cause intracranial hemorrhage. Capillary telangiec-tasias are usually found at autopsy. Cavernous malformations often present with seizures and, less frequently, with hemorrhage. AVMs are the most common vascular malformation to become symptomatic. Most AVMs become symptomatic...

Secondary CNS Lymphoma

Systemic lymphoma spreads to the CNS in about 10 of cases, most commonly in the setting of advanced or relapsing disease 47 . Certain sites of systemic disease are more likely to seed the CNS the testis, bone marrow, bone, orbit, peripheral blood and paranasal sinuses. Propensity to spread to the CNS also varies with histologic subtype. Low-grade lymphomas rarely metastasize to the brain. Most metastases are diffuse large-cell or high-grade lymphomas. High-grade histology, elevated LDH levels,...

Preoperative Assessment and Medication

In all cases, anesthetic care starts with a pre-operative visit and assessment by the anesthesiologist, who will be interested in the patient's general health, comorbidities, current medications and known allergies. For emergency cases, the time of last oral intake of food and fluids is important. The neurological status will be evaluated with particular regard to specific deficits, evidence of raised ICP, brainstem dysfunction and, in the case of cervical spine surgery, stability of the...

Preoperative Evaluation

Patients with primary pineal region tumors present with signs and symptoms of hydro-cephalus secondary to compression or involvement of the tectum, occluding the Sylvian aqueduct, including headaches, diplopia, lethargy and ataxia. Compression of the tectum may also cause Parinaud's syndrome, resulting in vertical gaze paresis, impaired pupillary light reflex and convergence nystagmus. The clinical presentation for germ cell tumors is dependent upon the sites of involvement. Suprasellar...

Skull Base Tumors

A bi-frontal bone flap is then raised, either as a free flap or pedicled on temporalis. Care should be taken to keep the dura intact whilst opening the bone. Exposure of the floor of the anterior fossa is best achieved by opening the dura on either side of the superior sagittal sinus as far anteriorly as possible. The sinus and underlying falx can then be divided between stay sutures. If a lumbar drain has been inserted, this can now be opened to allow CSF to drain....

The Slit Ventricle Syndrome

It is important to distinguish between the radiological label of slit ventricles, a not uncommonly seen appearance on post-shunt CT scans where the ventricles are barely recognisable but the patient is free of symptoms, and the less frequently encountered clinical symptom complex that may accompany slit-like ventricles. It has been estimated that only 11 of patients with radiologically confirmed slit ventricles demonstrated the clinical syndrome. The clinical syndrome is usually one of episodic...

Congenital Dermal Sinus

Infants are frequently referred to the pediatric neurosurgeon with a midline spinal dimple, occasionally with discharge from the tract. This may be the initial presentation of many congenital dermal sinuses but a significant number present with meningitis due to skin or gut organisms. Multiple episodes of meningitis may even occur before the diagnosis is made, since the cutaneous opening of the tract may be minute. Nevertheless, meningitis due to organisms such as Staphylococcus aureus or...

Pneumonia Antibiotics and Mechanical Ventilation

Pulmonary complications are common and are a major cause of morbidity and mortality for patients requiring neurointensive care. In one study on patients with SAH, half the deaths attributable to medical causes were pulmonary in origin. Risk of pneumonia appears to peak within the first 3 days (early-onset pneumonia or EOP) and has been found to be associated with trauma and, in non-trauma patients, with a Glasgow Coma Scale (GCS) of less than 9. In this cohort of patients, the organisms...

Lipomeningocele

Lipomeningocele is an abnormality of the spine characterized by a low-lying conus medullaris, infiltrated with fatty tissue, which extends through a bony dysraphic defect and into the subcutaneous tissues. It is thought to occur as a result of an abnormality of secondary neurula-tion of the caudal cell mass, whereby pluripo-tential mesenchymal cells fail to regress and may lead to lipomas, hamartomas and teratomas in the lumbosacral region. The lipoma is invariably covered by skin but may have...

Management of Peripheral Nerve Injuries

Management Nerve Injuries

The management of peripheral nerve injuries is largely determined by understanding the mechanism, and grade of injury. This involves evaluating an associated laceration and classifying the grade of the injury utilizing one of the schemes described above. The authors personally believe that most traumatic peripheral nerve injuries can be logically managed by utilizing the Seddon three-tier grading scheme, as described earlier 3 . The crux of this evaluation is that it is essential to...

Localization of Somatosensory Cortex Using SSEPs

SSEP mapping to identify the primary somatosensory gyrus provides a quick, reliable means of Rolandic localization in both adult and pediatric populations 28 . SSEPs can be performed under general anesthesia or in awake patients. SSEP mapping has the advantage over stimulation mapping that seizures cannot be evoked because the cortex itself is not stimulated. When performed under general anesthesia, halogenated anesthetic agents should be avoided because they may increase the latency of the...

Cranial Epidural Abscess EDA

Cranial EDA is a collection of pus that forms in the potential space between the dura and calvar-ium. Cranial EDA is relatively uncommon, accounting for only 5 of all localized intracranial infections 16,17 . Most cranial EDAs result from trauma with implantation of foreign material, following craniotomy or in association with infection of the para-nasal sinuses, although occasional cases are related to orbital cellulitis, sinus thrombophlebitis or congenital dermal sinuses. Rarely is cranial...

Info

CMV ventriculitis and polyradiculopathy Table 36.4. Medical therapy of selected HIV-associated CNS infections. Infection Therapy Dose and duration Cryptococcal meningitis Amphotericin B 0.6-0.8 mg kg day IV for 14 days, or until headache, 400 mg day until CSF culture negative, then decrease to 200 mg day and continue for life 100-200 mg load, then 75-100 mg day PO 10-50 mg day PO 4-8 g day 100 mg kg day PO divided into four doses 600-900 mg PO IV qid Initial therapy with fluconazole associated...

MRI Evaluation of Peripheral Nerve Trauma

The majority of serious peripheral nerve injuries do not lead to actual transection of the nerve, but rather leave the nerve in continuity. As described earlier, initially it may be difficult to distinguish closed nerve injuries that recover on their own neurapraxic and axonotmetic grades from those that do not neurotmetic grade and therefore require a surgical repair. Serial clinical and electrodiagnostic evaluations, often over a period of months, have traditionally been the mainstay of...

Neuromuscular Blocking Drugs

Neuromuscular blocking drugs, or muscle relaxants, facilitate intubation of the trachea and mechanical ventilation of the lungs, and prevent movement during surgery. They are charged molecules that do not cross the blood-brain barrier, and so have no direct cerebral effects. However, they may indirectly influence the central nervous system via cardiovascular side-effects, histamine release and active metabolites. These drugs may be depolarizers or non-depolarizers, depending on their mechanism...