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Biomedical subjects

S Constantini

Publications and source records attributed to S Constantini.

At least 55 records · Page 3Linked to original sources

Practical decisions in the treatment of pediatric brain stem tumors.

The treatment of brain stem gliomas has evolved over the last few decades, reflecting advances in imaging (MR), microsurgical techniques and biological understanding. The aim of this chapter is to provide a preoperative classification for intrinsic brain stem lesions that will predict histopathology and biological behavior from the clinical syndrome and the MR appearance. Such a classification system may help in selecting children with brain stem tumors that can benefit from surgery. Technical considerations, potential surgical complications, and the ways to avoid them are discussed.

Brain Neoplasms↗

Intramedullary spinal cord tumors in children under the age of 3 years.

Over a 13-year period extending from 1980 to 1993, 27 children less than 3 years of age underwent operation for removal of an intramedullary spinal cord tumor (IMSCT). The majority (18 of 27) of children had undergone surgery before being referred to New York University (NYU) Medical Center. The most common reasons for radiological investigation were pain (42%), motor regression (36%), gait abnormalities (27%), torticollis (27%), and progressive kyphoscoliosis (24%). Forty procedures were performed in 27 children. Nine children underwent two operations and two children underwent three procedures. A gross-total resection was achieved in 72% of the procedures. There was no surgical mortality. A comparison of the preoperative and 3-month postoperative functional grades for the first NYU procedure (NYU-1) yielded the following findings: 20 patients' conditions remained the same, five patients improved, and two patients deteriorated. The functional outcomes of a second operation (NYU-2) were similar. The majority of the children (24 of 27, 89%) had histologically determined low-grade lesions. There were 12 patients with low-grade astrocytomas (Grades I-III), eight with gangliogliomas, two with ganglioglioneurocytomas, one with a glioneurofibroma, and one child with a mixed astro/oligodendroglioma. Two children had anaplastic astrocytomas (Grades II-III) and one child had a glioblastoma multiforme. In a median follow-up review of 76 months, two patients died and two patients were lost to follow up. The 3- and 5-year progression-free survival (PFS) rates were 81.7% (standard error of the mean (SEM) 0.083) and 76.2% (SEM 0.094), respectively. Eight of 24 patients suffered a recurrence within a mean time of 45.4 +/- 28.9 months. All were treated with surgery (NYU-2). Lesions recurred in three of 12 children with low-grade astrocytomas, two of eight children with gangliogliomas, one child with an anaplastic astrocytoma, one child with a ganglioglioneurocytoma, and one child with a glioblastoma multiforme. At follow-up review, most of these children were doing well. Sixteen are in functional Grades I or II and 18 children attend a normal school system. The authors conclude that surgery for the removal of IMSCTs in children less than 3 years of age can be performed radically and safely. The postoperative functional performance is determined by the degree of the preoperative deficit. It is, therefore, of utmost importance to diagnose and treat these children as early as possible. Spinal cord tumors should be recognized as potentially excisable lesions on their initial presentation and when they recur. The optimum treatment for malignant lesions is still to be determined.

Child, Preschool↗

Compressive epidural autologous free fat graft in a patient with failed back syndrome: case report.

A patient who had undergone surgery twice previously for lumbar spine disease presented with paraparesis and urinary sphincter problems. Imaging showed a large epidural compressive lesion with the consistency of fat at the L3/4 level. At operation a large mass of compressing epidural fat was removed. This was an epidural autologous free fat graft placed in a previous operation when stabilizing the lumbar spine. The merits of a free fat graft in relation to the prevention of epidural scar and the failed back syndrome are discussed, and the significance of this complication was considered.

Adult↗

Prevention of recurrent tethered spinal cord.

One of the most problematic technical considerations in surgery for the release of tethered spinal cord is how to prevent recurrent tethering. Recurrent tethering is common because the spinal canal in the baby is shallow and, therefore, postoperatively, the neural contents are in direct contact with the posterior dura. The only way to prevent a recurrent tethered cord is to be certain that the neural elements remain free within circumferentially patent cerebrospinal fluid. We hereby describe a method where a curved 1.5 mm oval piece of Medpor is used to create a posterior space for the neural elements. The spinal canal is expanded posteriorly, therefore, creating an abnormally wide canal to accommodate the neural elements within subarachnoid space. This methodology was used in 18 neonate patients, and in late tethering cases after myelomeningocele. Technical and theoretical considerations are discussed.

Child, Preschool↗

Hypothalamic hamartoma and the Pallister-Hall syndrome.

The Pallister-Hall syndrome (PHS) was initially described as the congenital hypothalamic 'hamartoblastoma' syndrome in 1980. Cardinal manifestations of the syndrome consist of a hypothalamic hamartoma and extracranial abnormalities, initially thought to be fatal in the perinatal period. The original pathologic description of these hypothalamic lesions were from infants who died in the perinatal period and revealed small cells of variable density which resembled primitive undifferentiated germinal cells and appeared to invade the hypothalamic nuclei, suggesting a neoplastic potential. Hypothalamic lesions have now been removed from older infants and children with this syndrome and reveal a more mature histologic appearance typical of a hypothalamic hamartoma. We present 2 new cases of PHS who underwent surgery and demonstrate the maturational nature of the hypothalamic lesion and the phenotypic variability of the syndrome.

Abnormalities, Multiple↗

Spontaneous involution of an intra-axial brain stem lesion: a case report.

This report describes the spontaneous involution of an intrinsic brain stem lesion whose clinical and MRI characteristics strongly suggest a tumor etiology. Nonoperative experiences with central nervous system tumors have shown that they may sometimes exhibit prolonged periods of dormancy. There are several reports of 'disappearing' CT lesions which have all been inflammatory, infective, or immunological. No histologically proven tumor has been shown to spontaneously involute, nor have 'disappearing' lesions been described for MRI.

Brain Neoplasms↗

Current treatment of normal-pressure hydrocephalus: comparison of flow-regulated and differential-pressure shunt valves.

FROM THE RECORDS of approximately 1500 shunt operations performed between 1987 and 1992, we identified 37 adults between ages 38 and 86 years (mean, 70 yr) with the normal-pressure hydrocephalus (NPH) syndrome who underwent surgery by a single surgeon. Since 1990, we have routinely used a flow-regulated shunt system (Orbis-Sigma valve [OSV]; Cordis Corporation, Miami, FL) in these patients. In this study, we compared the OSV system with conventional differential-pressure (DP) shunt systems uniformly used before 1990. This series (n = 37) consisted of 62% men (n = 23) and 38% women (n = 14). We excluded all patients with hydrocephalus associated with central nervous system neoplasms, intracerebral hemorrhage, or trauma as well those with radiographically documented late-onset aqueductal stenosis. All patients presented with the NPH clinical syndrome, chiefly with magnetic gait. In addition, 75% of patients experienced cognitive loss and 59% experienced urinary incontinence. The mean duration of preoperative symptoms was 35 months (range, 7-120 mo). Eight patients (22%) had undergone previous shunting procedures before referral to our service. A total of 89 shunt operations were performed in the 37 patients. Using actuarial methods and controlling for a history of prior shunt surgery, we found no significant difference in the time to initial malfunction (shunt survival) between the OSV and the DP shunts. There were three subdural hematomas and one infection in the OSV group compared with no complications in the DP valve group (P = 0.11). Thirty-six patients were available for follow-up, at a mean of 14 months after surgery. Nearly 90% of all patients experienced improvement in gait after shunting, regardless of the valve system that was used. There was one unrelated death. Realizing the limitations of a retrospective analysis and on the basis of the limited number of patients in this study, we conclude that using actuarial methods, we found no significant difference in shunt survival when comparing the OSV with the standard DP valve shunt systems with antisiphon devices in patients with NPH. Contrary to previous reports, the OSV is not free of overdrainage complications. Most patients (89%) with the NPH syndrome who primarily presented with gait disorder experienced significant improvement in gait after either OSV or DP shunting procedures when selected for surgery on the basis of the clinical syndrome and confirmatory radiographic data.

Adult↗

The effects of methylprednisolone and the ganglioside GM1 on acute spinal cord injury in rats.

Recent clinical trials have reported that methylprednisolone sodium succinate (MP) or the monosialic ganglioside GM1 improves neurological recovery in human spinal cord injury. Because GM1 may have additive or synergistic effects when used with MP, the authors compared MP, GM1, and MP+GM1 treatments in a graded rat spinal cord contusion model. Spinal cord injury was caused by dropping a rod weighing 10 gm from a height of 1.25, 2.5, or 5.0 cm onto the rat spinal cord at T-10, which had been exposed via laminectomy. The lesion volumes were quantified from spinal cord Na and K shifts at 24 hours after injury and the results were verified histologically in separate experiments. A single dose of MP (30 mg/kg), given 5 minutes after injury, reduced 24-hour spinal cord lesion volumes by 56% (p = 0.0052), 28% (p = 0.0065), and 13% (p > 0.05) in the three injury-severity groups, respectively, compared to similarly injured control groups treated with vehicle only. Methylprednisolone also prevented injury-induced hyponatremia and increased body weight loss in the spine-injured rats. When used alone, GM1 (10 to 30 mg/kg) had little or no effect on any measured variable compared to vehicle controls; when given concomitantly with MP, GM1 blocked the neuroprotective effects of MP. At a dose of 3 mg/kg, GM1 partially prevented MP-induced reductions in lesion volumes, while 10 to 30 mg/kg of GM1 completely blocked these effects of MP. The effects of MP on injury-induced hyponatremia and body weight loss were also blocked by GM1. Thus, GM1 antagonized both central and peripheral effects of MP in spine-injured rats. Until this interaction is clarified, the authors recommend that MP and GM1 not be used concomitantly to treat acute human spinal cord injury. Because GM1 modulates protein kinase activity, protein kinases inhibit lipocortins, and lipocortins mediate anti-inflammatory effects of glucocorticoids, it is proposed that the neuroprotective effects of MP are partially due to anti-inflammatory effects and that GM1 antagonizes the effects of MP by inhibiting lipocortin. Possible beneficial effects of GM1 reported in central nervous system injury may be related to the effects on neural recovery rather than acute injury processes.

Animals↗

"Acquired" Chiari I malformation. Case report.

Tonsillar descent of the cerebellum in Chiari I malformations is often considered a congenital defect. A patient is presented in whom magnetic resonance (MR) imaging revealed normally positioned cerebellar tonsils; however, 1 year later MR imaging was repeated for evaluation of gait abnormalities and showed descent of the cerebellar tonsils. This case illustrates worsening symptoms with progressive descent of the cerebellar tonsils and suggests that Chiari I malformations can evolve postnatally.

Arnold-Chiari Malformation↗

Reversible opisthotonus following intracranial pressure changes in Chiari malformation.

A shunted myelodysplastic child with Chiari II malformation presented with shunt malfunction and opisthotonus. Correction of a distal obstruction lead to an initial improvement followed by overdrainage of cerebrospinal fluid and repetition of an opisthotonic posture. The possible mechanisms which unmask lower brainstem dysfunction in Chiari malformation when intracranial hyper- or hypotension exist, are discussed.

Arnold-Chiari Malformation↗

Persistent activation of thrombocytes in neurosurgical patients operated for primary brain tumours.

A prospective study was designed to investigate whether platelet hyperactivity exists following neurosurgical removal of primary brain tumours. The level of beta-thromboglobulin (beta TG), a protein released by platelets during the activation process, was measured in the plasma of 13 consecutive patients prior to surgery (T 1) and on the first (T 2) and seventh (T 3) post-operative days. A significant and sustained increase in beta TG levels from a baseline of 20.7 +/- 1.7 ng/ml (mean +/- sem) at T 1 to 37.0 +/- 5.2 ng/ml (p < 0.005) at T 2 and 35.9 +/- 3.7 at T 3 (p < 0.005) occurred. When patients were grouped according to tumour malignancy, significantly higher beta TG levels were found in the malignant group at T 2 (51.8 +/- 6.3 ng/ml) when compared to the benign group (30.6 +/- 6.0 ng/ml) (p = 0.025). Postoperative T 3 levels were linearly correlated to T 1 levels (r = 0.58, p = 0.04). This significant and sustained platelet activation that occurs following brain surgery may be part of the biochemical sequel leading to a hypercoagulable state and thrombo-embolic phenomena (TEP) in these patients.

Adolescent↗

[Prevalence and clinical aspects of A and B subgroups of respiratory syncytial virus infection. Observation of 8 consecutive epidemics between 1982 and 1990].

BACKGROUND: Infants suffering from respiratory syncytial virus (RSV) infection can have severe responses that require intensive care. This study compares the epidemiologic patterns and the severity of respiratory diseases produced by RSV strain subtypes A and B. POPULATION AND METHODS: The prevalence of RSV subgroups was studied over 8 consecutive outbreaks from 1982 to 1990. The files of 73 infants aged from 1 to 24 months admitted because of RSV infection between October 1987 and March 1990 were studied. The criteria of severity were tachypnea and/or the use of the accessory muscles for respiration, apnea and/or cyanosis, hospitalization for > 8 days, hypercapnia and/or acidosis, oxygen therapy, use of corticosteroids and/or bronchodilators, nutritional difficulties. RESULTS: A total of 374 RSV strains were isolated: 142 were group A and were 232 group B. Subtype A predominated during the winter 1987-1988 and subtype B during 1983-1984, 1984-1985 and 1989-1990. Some indicators of severity, such as degree of respiratory distress, duration of hospitalization and levels of oxygen saturation, were correlated with A subgroup infections, but the difference in the severity index for the two subtypes was not statistically significant. CONCLUSIONS: The results are not consistent with other previous reports, perhaps because different indicators of severity were used in this study and infants less than one month old or having other underlying diseases were excluded.

Acute Disease↗

Tumor prostaglandin levels correlate with edema around supratentorial meningiomas.

The pathophysiological mechanisms to explain peritumoral edema have not been clarified. Multiple aspects of brain edema secondary to supratentorial meningiomas were prospectively investigated in a group of 29 patients who underwent surgery consecutively. Sixty-nine tumor samples were analyzed for prostanoid levels. Levels of 6-keto-PGF1 alpha, the stable metabolite of prostacycline, were found to correlate well with the extent of edema (r = 0.51, P < 0.01). The ratio, 6-keto-PGF1 alpha x PGE2/TXB2, was found to have the best correlation with edema index (extension/tumor volume) (r = 0.69, P < 0.005). A case of a hemangiopericytic meningioma with the largest edema extent within the study group also exhibited the highest level of 6-keto-PGF1 alpha (2420 pg/mg protein). Steroid treatment (dosage, duration of therapy, and their product) did not correlate with prostaglandin levels. These findings may explain the inconsistent clinical effects of steroids on meningioma-induced edema. Possible explanations for this phenomenon are discussed. Otherwise, histology, pathological features of tumor aggressiveness, or mechanical parameters, such as its volume, location, and insertion site, did not correlate well with edema parameters or with prostaglandin levels. Similarly, tumor water content, imaging parameters in computed tomography and magnetic resonance, and operative findings (including dissection plane, vascularity, and tumor firmness) did not correlate well with edema parameters. Although a direct cause-effect relationship between prostaglandins and peritumoral edema is not conclusively established, the circumstantial evidence of the ability of prostaglandins to induce vasogenic brain edema and the robust association with peritumoral edema is persuasive.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗

[Transoral approach to the lower clivus and upper cervical spine].

5 cases were operated via a transoral approach for basilar impression (2 cases), tumor (2), or traumatic dislocation of the odontoid process (1). In all except 1 there was compression of the lower medulla and/or upper cervical cord. Posterior cervical fusion was also performed in 2 patients. There was significant improvement in all the patients who presented with neurological deficits. Surgical morbidity was low and there was no mortality. The use of the operating microscope, microdrill, self-retaining mouth retractor, flexible oral endotracheal tube, and intraoperative fluoroscopy permit a safe, direct approach to the lower clivus and upper cervical region.

Child, Preschool↗

Melanotic cerebral ganglioglioma: evidence for melanogenesis in neoplastic astrocytes.

A composite melanotic glial-ganglionic tumor was resected from a 17-year-old girl who presented with a 5-year history of epilepsy. Grossly, the tumor was partly cystic, partly solid, located superficially in the temporal lobe. Histologically, its glial component was composed of spindle and pleomorphic cells, including tumor giant cells, which were associated with Rosenthal fibers, eosinophilic granular bodies and marked desmoplasia. The cells had immunohistochemical and ultrastructural features of astrocytes, and some were invested by incomplete basal lamina. Thus, the tumor had many features in common with pleomorphic xanthoastrocytoma. However, its most striking feature was the presence of melanin pigment in numerous neoplastic cells. Immunoelectron microscopy revealed glial fibrillary acidic protein-positive intermediate filaments in tumor cells bearing melanosomes and premelanosome, proving their astrocytic nature. This case demonstrates, for the first time, melanosomal melanogenesis in human cells with astrocytic phenotype, and provides additional evidence for the ability of central neuroepithelial cell derivatives to produce melanin.

Adolescent↗

Fever as the initial sign of malfunction in non infected ventriculoperitoneal shunts.

Sixty eight children were treated for ventriculoperitoneal shunt malfunction in our department during the years 1984-1989. Fifteen (22%) developed fever above 37.5 degrees C as a presenting sign of their shunt malfunction. Physical examination did not reveal any reason for the fever. Cerebrospinal fluid, urine and blood cultures were all negative. All the children were operated upon and the malfunction corrected. Fever subsided twenty four to thirty six hours after the operation in all the patients. Fever of unknown origin in children with shunted hydrocephalus might be the first sign of a developing shunt malfunction and a neurosurgical examination should be requested.

Adolescent↗