SREDA: An Uncommon and Misleading EEG Rhythm.

Subclinical Rhythmic Electroencephalographic Discharges of Adults (SREDA) is a benign EEG variant characterized by sharply contoured rhythmic theta activity occurring bilaterally with maximum activity over the parietal or the posterior head region. These paroxysms are not associated with any objective or subjective clinical manifestations. SREDA, the rarest and last reported benign EEG pattern with no known clinical significance yet, is detailed in this case report. We provide the case of a gentleman with epilepsy who underwent vEEG recording in our lab. The described case is interesting due to its EEG characteristics as well as its clinical picture, which misled us for at least a while. It provides an illustration of how over interpretation of normal EEG patterns may result in an incorrect diagnosis.

Horner's syndrome secondary to T1-T2 intervertebral disc prolapse.

Background: T1-T2 intervertebral disc prolapse (IVDP) is a rare clinical condition. Horner's syndrome is an extremely rare clinical finding in these patients. Case Description: A 56-year-old man presented with the left C8 T1 radiculopathy, left hand grip weakness, and ipsilateral Horner's syndrome. Magnetic resonance imaging of the spine showed a contrast-enhancing lesion in the left T1 foramen compressing the left T1 nerve root. He underwent left T1 hemilaminectomy, upper half of left T2 hemilaminectomy and removal of the left foraminal lesion. A biopsy of the lesion was sent for histopathological diagnosis which revealed tissue consistent with disc material. Postoperatively, he had near-complete recovery with residual minimal Horner's syndrome. Conclusion: T1-T2 IVDP should be considered in the differential diagnosis when a patient presents with C8 T1 radiculopathy and Horner's syndrome.

Cerebral venous sinus thrombosis as a complication of cranial melioidosis - a rare case report.

Cerebral venous sinus thrombosis is a rare complication of cranial melioidosis. We report a case of an adult male who presented with skull osteomyelitis, transverse sinus thrombosis and multiple brain abscesses. His blood cultures grew Burkholderia pseudomallei . The patient finally succumbed after multiple recurrences of the infection despite surgical excision of the osteomyelitic bone and the recommended antibiotic treatment. The management of cerebral venous sinus thrombosis in patients with cranial melioidosis is discussed along with a brief review of the literature.

Ceftriaxone-induced encephalopathy in a patient with multicentric glioma.

Background: Ceftriaxone is a commonly used antibiotic in a wide range of local and systemic infections. Encephalopathy is a rare complication of ceftriaxone, often seen in older adults and those with renal insufficiency. Case Description: A 73-year-old lady with prior history of hypertension and dyslipidemia presented with the complaints of slurred speech, gait imbalance, nocturnal vomiting, and progressively worsening headache. A magnetic resonance imaging of the brain revealed two intracerebral lesions involving the right frontal and temporal lobes, suggestive of multicentric glioma. She underwent craniotomy and excision of these lesions. The biopsy was reported as intra-axial tumors with features suggestive of the WHO Grade IV glioma. Postoperatively, she did not wake up. An electroencephalogram demonstrated triphasic waves suggestive of encephalopathy. The probable diagnosis of ceftriaxone-induced encephalopathy was made after ruling out other causes of delayed awakening after surgery. Ceftriaxone was discontinued and the patient improved within 2 days of withdrawal of ceftriaxone. Conclusion: Drug-induced encephalopathy should be considered in the differential diagnosis of patients with delayed awakening after surgery. Discontinuation of the drug leads to the recovery of these patients.

Stenotrophomonas maltophilia as a rare cause of meningitis and ventriculoperitoneal shunt infection.

Stenotrophomonas maltophilia is an extremely rare pathogen responsible for ventriculoperitoneal shunt infection and meningitis. This young female patient with history of multiple shunt revisions in the past, came to us with shunt dysfunction and exposure of the ventriculoperitoneal shunt tube in the neck. The abdominal end of the shunt tube was seen migrating into the bowel during shunt revision. The cerebrospinal fluid analysis showed evidence of Stenotrophomonas maltophilia growth. This is the first reported case of Stenotrophomonas maltophilia meningitis associated with ventriculoperitoneal shunt migration into the bowel.

Posttraumatic Intralaminar Hematoma Developing between Cranial Dural Layers: A Case Report.

We present a case of post-traumatic hematoma developing between the 2 layers of the cranial dura in a 2-year-old child following head injury. This child presented with history of fall from a height in altered sensorium with paucity of movements on the left side. Computerized tomography scan of the brain showed a right parietal linear fracture with an underlying hyperdense biconvex hematoma. Emergency evacuation of the hematoma was done. On elevation of the scalp flap, a fibrous membrane was seen protruding between the fracture lines. Following craniotomy, the hematoma was identified between the 2 layers of the dura and the fibrous membrane that protruded between the fracture lines was identified as the endosteal layer of dura. The hematoma was evacuated after opening the outer endosteal layer. After evacuation of the hematoma, the endosteal and meningeal layers could be identified separately and the point where these 2 layers split to enclose the hematoma was identified at the outer border of the hematoma. The child had no neurological sequel at the time of discharge.

The role of endoscopic third ventriculostomy in the treatment of hydrocephalus.

OBJECT: Hydrocephalus remains a major public health problem. Conventional treatment has relied on extracranial shunting of CSF to another systemic site, but this approach is associated with a high rate of complications. Endoscopic third ventriculostomy (ETV) is a novel treatment for select forms of hydrocephalus that can eliminate the need for implantation of a lifelong ventricular shunt system. However, the indications for ETV are contested and its long-term effectiveness is not well established. METHODS: The authors selected 100 consecutive patients who underwent ETV for hydrocephalus beginning in 1994. Patients were enrolled and treated at a single institution by a single surgeon. The primary outcome was success of ETV, with success defined as no need for subsequent surgery for hydrocephalus. RESULTS: Ninety-five patients satisfied the inclusion criteria. The mean follow-up period was 5.1 years (median 4.7 years) with follow-up data available for as long as 17 years. Patients commonly presented with headache (85%), ataxia (34%), emesis (29%), and changes in vision (27%). The success rate for ETV was 75%. Twenty-one patients (22%) in the series had malfunctioning shunts preoperatively and 13 (62%) were successfully treated with ETV. Preoperative inferior bowing of the third ventricle floor on MRI was significantly associated with ETV success (p < 0.05). CONCLUSIONS: Endoscopic third ventriculostomy is an effective and durable treatment for select patients with hydrocephalus. When successful, the procedure eliminates the lifelong complications associated with implanted ventricular shunts.

Rhombencephalosynapsis: embryopathology and management strategies of associated neurosurgical conditions with a review of the literature.

OBJECT: Rhombencephalosynapsis (RS) is a rare congenital posterior fossa malformation characterized by dorsal fusion of the cerebellar hemispheres, hypogenesis or agenesis of the vermis, and fusion of the dentate nuclei and superior cerebellar peduncles. The objective of this institutional study is to review the clinical conditions associated with RS and analyze the varied biological profile of this unique condition. METHODS: The study data were collected retrospectively from the medical records of patients at Rainbow Babies and Children's Hospital. After required institutional review board approval, the authors obtained information regarding the cases of RS reviewed by the Departments of Radiology, Genetics, and/or Pediatric Neurology. Medical charts were systematically reviewed, and 9 patients were analyzed in detail. RESULTS: The authors describe 6 cases of RS and 3 cases of partial RS. This case series demonstrates an association between RS and symptomatic hydrocephalus (7 of 9 patients) and RS and Chiari malformation (5 of 9 patients). Patients with symptomatic hydrocephalus underwent endoscopic third ventriculostomy or ventriculoperitoneal shunt insertion. One of the patients with an associated Chiari malformation underwent foramen magnum decompression. CONCLUSIONS: The authors present a large case series of RS. Patients with RS often had hydrocephalus and/or a Chiari Type I or II hindbrain malformation. Neuroimaging findings of RS are presented along with hypotheses to explain the embryopathology of this unusual condition.

Endoscopic transventricular selective amygdalohippocampectomy: cadaveric demonstration of a new operative approach.

OBJECTIVE: The microsurgical anatomy of the temporal region has been well described. However, there is a paucity of information about the transventricular endoscopic anatomy of the mesial temporal lobe, and little is known about endoscopic approaches to this region. In this report, we describe the technique of endoscopic amygdalohippocampectomy (AH). The endoscopic anatomy of the mesial temporal region both before and after AH is shown. METHODS: We used 4 silicon-injected cadaver heads for the study in our minimally invasive neurosurgery laboratory. The lateral ventricle was accessed through an occipital burr hole. RESULTS: Predissection transventricular endoscopic anatomy of this region showed the choroid plexus, hippocampus, amygdala, choroid fissure, and collateral eminence. The hippocampus, parahippocampal gyrus, and amygdala were removed endoscopically, keeping the pia on the inferior surface of the mesial temporal region intact. Postdissection anatomy of the mesial temporal region showed a clear view of the brainstem, posterior cerebral vessels, choroidal vessels, and tentorium. CONCLUSIONS: We studied the transventricular endoscopic anatomy of the mesial temporal region and described a technique for safe endoscopic AH. The advantages and potential risks of endoscopic AH are discussed, along with suggestions for minimizing complications. We believe that knowledge of the endoscopic anatomy of the mesial temporal lobe will be useful for endoscopic AH and the removal of other lesions in this region.

Anatomic hemispherectomy: historical perspective.

The history of surgical treatment for hemispheric epilepsy is rich with colorful twists and turns. The authors trace the evolution of the surgical treatment of hemispheric epilepsy from radical anatomic resections to current less invasive disconnection procedures. Anatomic hemispherectomy (AH) was first described by Dandy in 1928 as a treatment for gliomas. The first report of this technique to control seizures was by McKenzie in 1938. AH gained wide popularity but began to fall out of favor after the description of superficial cerebral hemosiderosis in 1966. To reduce the morbidity and mortality associated with AH, Rasmussen introduced functional hemispherectomy in 1974. The technique of hemispherotomy was introduced in the 1990 s to minimize the extent of brain removal while maximizing the white matter disconnections. Thus, surgery for hemispheric epilepsy has undergone dramatic transformation since the technique was first introduced. Less invasive techniques have been developed to reduce surgical morbidity. Although optimal seizure control is best achieved with radical AH, the newer less invasive disconnection techniques appear to achieve near-comparable postoperative seizure control with a significantly lower rate of complications.

Utility of diffusion tensor imaging tractography in decision making for extratemporal resective epilepsy surgery.

PURPOSE: To assess the utility of diffusion tensor imaging tractography (DTIT) in decision making in patients considered for extratemporal resective epilepsy surgery. METHODS: We subjected 49 patients with drug-resistant focal seizures due to lesions located in frontal, parietal and occipital lobes to DTIT to map the white matter fiber anatomy in relation to the planned resection zone, in addition to routine presurgical evaluation. We stratified our patients preoperatively into different grades of risk for anticipated neurological deficits as judged by the distance of the white matter tracts from the resection zones and functional cortical areas. RESULTS: Thirty-seven patients underwent surgery; surgery was abandoned in 12 (24.5%) patients because of the high risk of postoperative neurological deficit. DTIT helped us to modify the surgical procedures in one-fourth of occipital, one-third of frontal, and two-thirds of parietal and multilobar resections. Overall, DTIT assisted us in surgical decision making in two-thirds of our patients. CONCLUSIONS: DTIT is a noninvasive imaging strategy that can be used effectively in planning resection of epileptogenic lesions at or close to eloquent cortical areas. DTIT helps in predicting postoperative neurological outcome and thereby assists in surgical decision making and in preoperative counseling of patients with extratemporal focal epilepsies.

Frameless stereotactic endoscope-assisted transoccipital hippocampal depth electrode placement: cadaveric demonstration of a new approach.

PURPOSE: Hippocampal recording using depth electrodes is indicated in a small subgroup of patients with medically intractable seizures. There are several conventional techniques for implantation of hippocampal depth electrodes. We describe a new method for hippocampal depth electrode placement using an image-guided endoscopic transoccipital route. This technique is simple and effective, eliminating several drawbacks of conventional techniques. METHODS: One silicone-injected cadaver head was used. A rigid endoscope sheath was inserted through a transoccipital corridor into the atrium of the lateral ventricle and then advanced to the temporal horn. Each of the hemispheres was cannulated. The hippocampus was identified visually, and a depth electrode was inserted into the substance of the hippocampus along its long axis under direct vision. RESULTS: In both hemispheres we were able to successfully implant the depth electrode within the hippocampus. The advantages of our technique over conventional approaches are (1) there is no need for frame-based stereotaxy, thus reducing operating time and patient discomfort, (2) the electrodes are inserted into the hippocampus under direct endoscopic visualization, reducing the chance of injury to vascular structures, (3) there is no need to insert a larger cannula into the hippocampus before placement of the electrodes, reducing trauma to the hippocampus, and (4) the number of electrodes within the hippocampus can be assessed at the end of the procedure, reducing malposition. CONCLUSION: We believe that image-guided endoscopic transoccipital hippocampal depth electrode placement can be performed with precision equal or superior to conventional techniques but without their major disadvantages.

Symptomatic posterior fossa and supratentorial subdural hygromas as a rare complication following foramen magnum decompression for Chiari malformation Type I.

Symptomatic subdural hygroma due to foramen magnum decompression for Chiari malformation Type I is extremely rare. The authors present their experience with 2 patients harboring such lesions and discuss treatment issues. They conclude that the possibility of subdural hygromas should be considered in all patients presenting with increased intracranial tension following foramen magnum decompression for Chiari malformation Type I. Immediate neuroimaging and appropriate surgical intervention provides a good outcome.

Endoscopic total corpus callosotomy: cadaveric demonstration of a new approach.

BACKGROUND: Callosotomy is a surgical option for treatment of a small number of patients with intractable seizures who are not candidates for surgical resection. The procedure is done conventionally with the aid of a microscope. In this article, we describe a new technique of endoscopic callosotomy through a parasagittal burr hole in a cadaveric model. METHODS: We utilized this technique with a single frontal burr hole. Callosotomies were performed on 4 silicon-injected cadaver heads in our minimally invasive neurosurgical laboratory. RESULTS: We were able to successfully perform total callosotomies in all cadaveric specimens without injury to the adjacent neurovascular structures. The advantages of our technique over microsurgery are the minimally invasive nature of the exposure and the improved visualization of the vascular structures near the rostrum and genu of the corpus callosum. A potential disadvantage we anticipate is the difficulty controlling bleeding in the event of vascular injury. CONCLUSION: We believe that this minimally invasive approach could have potential clinical applications.

Unusual Resolution of a depressed skull fracture following repeat head trauma: the two-hit hypothesis?

An infant sustained a significant depressed skull fracture from a fall. Before the planned surgical repair of the fracture could be carried out, the child sustained a second fall that led to the complete resolution of the depressed fracture. Mechanisms to explain this unusual phenomenon are discussed.

Minimally invasive endoscopic transventricular hemispherotomy for medically intractable epilepsy: a new approach and cadaveric demonstration.

OBJECT: Surgery for medically intractable epilepsy secondary to unihemispheric pathology has evolved from more aggressive hemispherectomy to less aggressive variations of hemispherotomy. The authors propose a novel minimally invasive endoscopic hemispherotomy that should give results comparable to conventional open craniotomy and microsurgery. METHODS: Endoscopic transventricular hemispherotomy was performed in 5 silicon-injected cadaveric heads in the authors' minimally invasive neurosurgery laboratory. The lateral ventricle was accessed endoscopically through a frontal and occipital bur hole. White matter disconnections were performed to unroof the temporal horn and to disconnect the frontobasal region, corpus callosum, and fornix. RESULTS: Using an endoscopic transventricular approach, all white matter disconnections were successfully performed in all 5 cadavers. CONCLUSIONS: The authors have demonstrated the feasibility of endoscopic transventricular hemispherotomy in a cadaveric model. The technique is simple and could be useful in a subgroup of patients with parenchymal volume loss and ventriculomegaly.