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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
PubMed1995

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↗
PubMed1995

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↗
PubMed1995

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↗
PubMed1995

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↗
PubMed1995

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↗
PubMed1994

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↗
PubMed1994

"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↗
PubMed1993

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↗
PubMed1993

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↗
PubMed1993

[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↗
PubMed1993

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↗
PubMed1992

[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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

Cardiac vagal tone predicts outcome in neurosurgical patients.

OBJECTIVE: To evaluate the relationship between presurgical levels of cardiac vagal tone and outcome in neurosurgical patients. DESIGN: Prospective series. SETTING: Respiratory ICU in a university hospital. PATIENTS: Fifty-one adults admitted to the respiratory ICU between 1982 and 1985. Forty-two patients were scheduled for elective neurosurgery, and nine patients suffered from head trauma. INTERVENTIONS: Ten minutes of electrocardiographic (EKG) data were recorded before medical intervention. Neurosurgical patients scheduled for surgery had EKG data recorded 24 hrs before their operation. Trauma patients had EKG data recorded immediately after arrival in the respiratory ICU. MEASUREMENTS AND MAIN RESULTS: Cardiac vagal tone was evaluated using a vagal tone index, quantified from the EKG. Cardiac vagal tone monitored before surgical intervention significantly distinguished between the outcome groups only for the elective neurosurgical patients. Age, gender, heart rate, Glasgow Coma Scale scores, and tumor location, size, and malignancy were not related to outcome in the elective neurosurgery group. However, within the trauma group, low Glasgow Coma Scale scores were significantly related to poor outcome. CONCLUSIONS: Cardiac vagal tone may offer important predictive value by alerting the physician to the functional consequence of head injury. Information relating to autonomic nervous system functioning, such as the vagal tone index used in this study, may provide additional information that will complement the computed tomography scan results. This study demonstrates that the vagal tone index is a predictive factor that may be efficiently extracted from the heart rate pattern routinely monitored in ICUs.

Adolescent↗