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Biomedical subjects

H L Rekate

Publications and source records attributed to H L Rekate.

At least 37 records · Page 2Linked to original sources

Elevated intracranial venous pressure as a universal mechanism in pseudotumor cerebri of varying etiologies.

Pseudotumor cerebri (PTC), or idiopathic intracranial hypertension, is a syndrome associated with multiple clinical conditions. We hypothesize that most if not all etiologies result in an increase in intracranial venous pressure as a final common pathway. We studied 10 patients with PTC. Five had dural venous outflow obstruction as demonstrated by venography, and the five remaining patients had normal venous anatomy. Pressure measurements, made during venography in eight patients, all showed elevated pressures. Pressure measurements in the superior sagittal sinus ranged from 13 to 24 mm Hg (mean, 16.6 mm HG). Patients with obstruction tended to have a high pressure gradient across the stenotic segment. Five patients with normal dural venous anatomy had elevated right atrial pressures (range, 6 to 22 mm Hg; mean, 11.8 mm Hg), which were transmitted up to the intracranial venous sinuses. Endovascular techniques, including angioplasty and infusion of thrombolytic agents in some cases, improved outlet obstruction from a hemodynamic perspective but were ineffective in consistently and reliably alleviating the clinical manifestations of PTC. Patients in both groups tended to respond well to conventional CSF diversion procedures. Our study suggests that elevated intracranial venous pressure may be a universal mechanism in PTC of different etiologies. This elevated venous pressure leads to elevation in CSF and intracranial pressure by resisting CSF absorption. Although the mechanism leading to venous hypertension in the presence of outflow obstruction is obvious, the etiology of increased intracranial and central systemic venous pressure in PTC remains obscure.

Adolescent↗

Postoperative chemotherapy and delayed radiation in infants and very young children with choroid plexus carcinomas. The Pediatric Oncology Group.

Eight infants with choroid plexus carcinomas were treated with surgery, prolonged postoperative chemotherapy and delayed radiation. The results suggest that some infants with choroid plexus carcinomas can be successfully treated with multimodality therapy, even allowing children with less than a gross total resection to have prolonged disease-free intervals.

Antineoplastic Combined Chemotherapy Protocols↗

Controlled lumbar drainage in pediatric head injury.

A retrospective study of external lumbar subarachnoid drainage in 16 pediatric patients with severe head injuries is presented. All patients had Glasgow Coma Scale scores of 8 or lower at 6 hours postinjury and were initially treated with ventriculostomy. Five patients required surgical evacuation of focal mass lesions. All patients manifested high intracranial pressures (ICPs) refractory to aggressive therapy, including hyperventilation, furosemide, mannitol, and in some cases, artificially induced barbiturate coma. After lumbar drainage was instituted, 14 patients had an abrupt and lasting decrease in ICP, obviating the need for continued medical management of ICP. In no patient did transtentorial or cerebellar herniation occur as a result of lumbar drainage. It was also noted retrospectively that the patients in this study had discernible basilar cisterns on computerized tomography scans. Fourteen patients survived; eight made good recoveries, three are functional with disability, and three have severe disabilities. Two patients died, most likely from uncontrolled ICP before the lumbar drain was placed. It is concluded that controlled external lumbar subarachnoid drainage is a useful treatment for pediatric patients with severe head injury when aggressive medical therapy and ventricular cerebrospinal fluid evacuation have failed to control high ICP. Selected patients with elevated ICP, which may be a function of posttraumatic cerebrospinal fluid circulation disruption and/or white matter cerebral edema, can be treated with this modality, which accesses the cisternal spaces untapped by ventriculostomy.

Adolescent↗

Diastematomyelia: a congenital anomaly not to be confused with a giant hairy nevus.

The role of the plastic surgeon in the diagnosis and management of congenital anomalies is often a complicated one that involves the integration of input from numerous specialists into the evaluation process. Diastematomyelia is a serious neurosurgical problem that often presents with cutaneous findings in a neurologically asymptomatic patient. Early recognition of these cutaneous manifestations by the plastic surgeon, evaluation with an MRI scan, and consultation with a pediatric neurosurgeon can prevent delayed diagnosis of this surgically correctable anomaly and irreversible neurologic sequelae.

Adolescent↗

The usefulness of mathematical modeling in hydrocephalus research.

A mathematical model of the regulation of ventricular volume, which emphasizes the importance of the intrinsic properties (turgor) of the brain for the understanding of hydrocephalus, has been developed. How the model was generated is described. The use of the model for understanding the various forms of hydrocephalus is discussed. Finally, the usefulness of the model in solving difficult clinical problems, such as diffuse pediatric head injury and progressive ventriculomegaly with low intracranial pressure, is described.

Adult↗

Cardiopulmonary bypass, hypothermic circulatory arrest and barbiturate cerebral protection for the treatment of giant vertebrobasilar aneurysms in children.

Intracranial aneurysms in the pediatric population are rare lesions with a significant proportion occurring as giant aneurysms involving the vertebrobasilar system. The complex anatomy of these lesions frequently creates an extremely difficult management dilemma. We present two patients, a 9-year-old and a 13-year-old, with giant fusiform vertebrobasilar aneurysms, to illustrate the utility of cardiopulmonary bypass, hypothermic circulatory arrest and barbiturate cerebral protection for successful surgical treatment of these complex intracranial vascular lesions in children.

Adolescent↗

Delayed postoperative tethering of the cervical spinal cord.

Tethering of the spinal cord in the lumbar and sacral regions of children with congenital anomalies is a well-recognized problem; however, tethering in the cervical region has rarely been reported. A search of the literature revealed no reports of symptomatic postoperative cervical spinal cord tethering. The authors present five cases of delayed postoperative cervical spinal cord tethering and discuss the benefit of detethering in these patients. All five patients were young (16 to 42 years of age) at presentation. All had done well after an initial surgical procedure but returned between 1 and 31 years postoperatively with symptoms including severe headache, upper-extremity pain, and progressive neurological deficits. In each case, magnetic resonance imaging indicated dorsal tethering of the cord in the cervical region. Surgical exploration with microscopic sharp detethering of the cervical cord was performed on each patient with favorable results. To avoid retethering, wide Tutoplast duraplasty is recommended.

Adolescent↗

Combined surgical and endovascular treatment of a giant vertebral artery aneurysm in a child. Case report.

The case is presented of a 5-year-old child who suffered a subarachnoid hemorrhage from a giant left vertebral artery-posterior inferior cerebellar artery (PICA) aneurysm. Initial treatment consisted of surgical occlusion of the parent vertebral artery combined with a PICA-to-PICA bypass. Because of persistent filling of the aneurysm, the left PICA was occluded at its takeoff from the aneurysm. Endovascular coil occlusion of the aneurysm and the distal left vertebral artery enabled complete elimination of the aneurysm. Follow-up magnetic resonance imaging and arteriography performed 6 months postoperatively showed persistent occlusion and elimination of the mass effect. Combined surgical bypass and endovascular occlusion of the parent artery may be a useful adjunct in the management of these aneurysms.

Anastomosis, Surgical↗

Traumatic occipitoatlantal dislocations.

Fourteen occipitoatlantal dislocations were treated during an 11-year period. All patients presented with neurological deficits and definite evidence of spinal instability. Plain radiographs provided the diagnosis conclusively in 11 patients. Three patients required computed tomography (CT) or magnetic resonance (MR) imaging for diagnosis. Rotational subluxations were radiographically occult and associated with less severe neurological injuries compared to distracted or translated subluxations. Ten patients died acutely. One patient, who had complete C1 level quadriplegia, died after 3 months. Three patients with incomplete spinal cord syndromes had long-term survival and functional neurological recoveries. Extensive ligamentous injury predisposed patients to recurrent subluxations. In several patients, traction or a cervical collar caused distraction and neurological injury. Halo immobilization and urgent fusion are necessary for patients with salvageable neurological function. Nonoperative measures are inadequate for immediate or long-term spinal stability.

Accidents, Traffic↗

Classification of slit-ventricle syndromes using intracranial pressure monitoring.

The term slit-ventricle syndrome appears to have different meanings to different authors. This study proposes a sublcassification of headaches in shunted children based on data obtained from chronic monitoring of intracranial pressure in 7 symptomatic children. Five distinct syndromes are identified: (1) intermittent, extremely low pressure headaches that are analogous to spinal headaches, (2) intermittent proximal obstruction, (3) shunt failure with small ventricles ('normal volume hydrocephalus'), (4) intracranial hypertension with working shunts (hydrocephalic pseudotumor), and (5) headaches unrelated to shunt function. We would prefer to limit the use of the term slit-ventricle syndrome to the triad of intermittent headaches lasting 10-30 min, smaller than normal ventricles on imaging studies, and slow refill of shunt-pumping devices. In other situations, a description relating to the presumed pathogenesis should be used.

Algorithms↗

Fluid, blood, and blood product management in the craniofacial patient.

This report is a retrospective review of the perioperative management of 56 children who underwent craniofacial surgical procedures. The use of a combination of 5% dextrose in normal saline or 5% dextrose in Ringer's lactate and normal saline resulted in postoperative sodium values in a normal range. In patients receiving a combination of 5% dextrose and electrolyte No. 48 and normal saline, the mean postoperative sodium level was 130 mEq/l with 9 of 18 patients below 130 mEq/l. Two patients in the series suffered clinical seizures on postoperative day 1 as a result of serum sodium levels of 122 and 121 mEq/l, respectively. We recommend that only solutions with a sodium content between 77 and 154 mEq/l be used routinely in the perioperative management of craniofacial patients.

Adolescent↗

Time course of intraventricular pressure change in a canine model of hydrocephalus: its relationship to sagittal sinus elastance.

Hydrocephalus was induced in adult greyhounds by intracisternal kaolin. Intraventricular pressure (IVP) was monitored in the conscious animal for 2 weeks using a small implantable sensor, and the time-course of IVP change was characterized. Intraventricular pressure increased significantly within 36 h of kaolin infusion and gradually subsided to normal values within 1 week. Enlargement of the lateral ventricles was not observed during the early phase of intracranial hypertension (less than 2 days). Evolving hydrocephalus and intracranial hypertension increased the elasticity (dP/dV) of the sagittal sinus. This effect was statistically significant (p < 0.05) and is possibly reversible in the acute stage. Normotensive hydrocephalus (1 and 2 weeks after kaolin) was associated with an irreversible increase in resistance to outflow (i.e., increased sagittal sinus elasticity). Sagittal sinus venography of animals with obvious ventricular enlargement (at least 1 week after kaolin) showed development of venous collaterals and atypical outflow pathways.

Animals↗

Chronic tonsillar herniation and Crouzon's syndrome.

Patients born with craniofacial syndromes such as Crouzon's syndrome will often develop hydrocephalus after their initial craniofacial reconstructive procedures. We have treated 10 patients with Crouzon's syndrome; 5 patients required a shunting procedure after cranial remodeling. Each of these 5 shunted patients later demonstrated chronic tonsillar herniation on magnetic resonance imaging studies. One of these patients exhibited signs of pseudotumor cerebri and 1 had a spastic quadriparesis. Of the 5 patients who did not require a shunt, none displayed chronic tonsillar herniation. Our evidence suggests that jugular foramen stenosis produces an increased cerebral venous turgor that leads to a cerebrospinal fluid absorption defect and hydrocephalus. After the hydrocephalus is treated the increased venous turgor remains and provides the driving force for the development of chronic tonsillar herniation.

Cerebellar Diseases↗

Pediatric spinal cord injury without radiographic abnormalities: report of 26 cases and review of the literature.

Spinal cord injury without radiographic abnormality (SCIWORA) occurs primarily in the pediatric population but is less common than other forms of spinal injury among children. Between 1972 and 1990, 159 pediatric patients were admitted to the Barrow Neurological Institute with acute traumatic spinal cord or vertebral column injuries. Of these, 26 children (16%) sustained SCIWORA. The mechanism of injury, its severity, and the prognosis for recovery were related to the patient's age. In young children, SCIWORA accounted for 32% of all spinal injuries and tended to be severe; 70% were complete injuries. In older children, SCIWORA accounted for only 12% of the spinal injuries, was rarely associated with a complete injury, and had an excellent prognosis for complete recovery of neurologic function. As with other types of spinal cord injuries, the severity of neurological injury was the most important predictor of outcome. Patients with complete neurological deficits from SCIWORA had a poor prognosis for recovery of neurological function.

Adolescent↗