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Biomedical subjects

N Sörensen

Publications and source records attributed to N Sörensen.

At least 19 recordsLinked to original sources
PubMed1998

Decompressive craniectomy in patients with uncontrollable intracranial hypertension.

There has been controversial discussion about the benefits of decompressive craniectomy in patients with critically raised intracranial pressure (ICP) after severe head injury. The aim of this retrospective study was to analyze the results of secondary decompressive craniectomy in patients with uncontrollable raised ICP after maximum aggressive medical treatment. The data of 28 patients (mean age 22 years, range 8-44 years) with severe head injury and posttraumatic cerebral edema were analyzed retrospectively. Surgery was not indicated in patients with vast primary lesions, hypoxia, ischemic infarction, brainstem injuries and central herniation. The outcome was classified according to the Glascow Outcome Scale (GOS) after one year. The decompressive crainectomy was performed an average of 68 hours after trauma, and ICP (< 25 mm Hg) decreased always while cerebral perfusion pressure (CPP > 75 mm Hg) improved as well as cerebral blood flow and microcirculation to normal values. 15 patients (56%) had a good outcome after one year (GOS 4 + 5). 5 patients (18%) were severely disabled, 4 patients (14%) remained in vegetative state and 3 patients (11%) died. Decompressive craniectomy should be kept in mind as the last therapeutic step, especially in young patients with head injury and raised ICP, which is not controllable with conservative methods.

Adolescent↗
PubMed1998

Perioperative fluid and electrolyte management in children undergoing surgery for craniopharyngioma. A 10-year experience in a single institution.

In a retrospective study, the intra- and early postoperative data of 39 children with 46 operations for craniopharyngioma were analyzed. Diabetes insipidus (DI) occurred in 30 out of 32 cases without preoperative evidence of DI. We observed that all children who did not have a pituitary stalk preserved and 5 out of 7 patients with preserved pituitary stalk developed DI within 18 h of surgery. Short-term inappropriate secretion of antidiuretic hormone (SIADH) occurred in 2 children, but was quickly followed by DI. The time of onset of DI and SIADH did not correlate with sex, age, body weight, location of tumor, or duration or extent of surgery. Parenteral desmopressin was an effective treatment for intra- and postoperative DI. The duration of the clinical effect of desmopressin administration varied in different patients between 4 and 23 h. An approach to the immediate intra- and postoperative management of children with craniopharyngioma is presented.

Administration, Intranasal↗
PubMed1998

Favorable outcome of giant cell glioblastoma in a child. Report of an 11-year survival period.

Giant cell glioblastomas are defined as glioblastomas with a marked predominance of bizarre, multinucleated giant cells. They represent about 5% of all glioblastomas and can occur at any site of the central nervous system, but the temporal and frontal lobes are the sites of predilection. Overall, giant cell glioblastomas show a prolonged survival period compared with common glioblastoma multiforme, and survival periods of 7 and 9 years have been reported in adults. Here we report on a child aged 11 years at diagnosis, who has so far survived for 11 years since operation and adjunctive radio- and chemotherapy.

Adult↗
PubMed1998

A possible role for somatostatin receptor scintigraphy in the diagnosis and follow-up of children with medulloblastoma.

The surgical resection of medulloblastoma (MB), the most frequent malignant brain tumor in children, often remains subtotal. To estimate the response to further treatment the residual tumor is monitored by CT or MRI. The interpretation of both imaging techniques is complicated by disturbances resulting from surgery and radiation. Our study searched for alternative imaging techniques and asked the following questions. 1) Do MB express somatostatin receptors (SSTR), 2) is SSTR scintigraphy a sensitive imaging technique for the follow-up and the detection of vital tumor tissue in children with MB, and 3) do the results of SSTR scintigraphy correlate with the in vitro analysis of MB tissue by SSTR autoradiography. We analyzed the SSTR status in 20 children with MB, aged 1 to 15 years. Sixteen SSTR scintigraphies using Indium-111-DTPA-D-Phel-pentetreotide were performed in 14 children. MB tissue of 14 children was analyzed by SSTR autoradiography using Iodine-125-Tyr3-octreotide. In 8 cases SSTR were measured by both methods in vivo and in vitro. In comparison with conventional imaging, results of SSTR scintigraphy were true positive in 7 of 7 patients, true negative in 9 of 9 patients, including one patient with false positive findings in MRI, false negative in only one patient with small spinal metastases (diameter < 3 mm) and false positive in none of the analyzed patients. In all cases with residual tumor (n = 3) and suspected relapse (n = 4) the diagnosis could be confirmed (n = 4) or excluded (n = 3), consistent with the results of MRI and tumor histology. All MB tissues analyzed by SSTR autoradiography (n = 14) showed an extremely high density of SSTR ranging from 4047 to 15526 dpm/mg MB tissue. MB (n = 8) which were analyzed by SSTR scintigraphy and autoradiography demonstrated consistent results in evaluation by both methods. In cases where the integrity of the blood-brain barrier was tested by Tc-99m-DTPA scintigraphy (n = 10), the SSTR-to-brain scintigraphy index confirmed the tumor specificity of radionuclide uptake. We conclude that 1) MB tissue expresses a particularly high density of SSTR, 2) the high density of SSTR in autoradiography correlates with a sensitive imaging of these tumors by SSTR scintigraphy, 3) SSTR scintigraphy might be a valuable imaging method for detection of vital MB tissue in patients with residual tumor or relapse.

Adolescent↗
PubMed1998

Epilepsy in shunt-treated hydrocephalus.

Although epilepsy is commonly associated with shunt-treated hydrocephalus, its relation to the shunting procedure and the criteria identifying postoperative epilepsy remain controversial. Of 283 patients shunted at Würzburg University Hospital over a 24-year period (1970 to 1994), 182 were followed up for a minimum of 1 year after shunt insertion and entered the study. The data were analyzed retrospectively in 1995 and 1996. Epilepsy was analyzed in relation to the etiology of hydrocephalus, functional status, time and site of shunt insertion, onset of seizures and seizure type, EEG changes, sex, shunt systems, and shunt revisions. Of the 182 patients studied, 37 (20%) developed epilepsy. The incidence of epilepsy varied according to the etiology of hydrocephalus: posthemorrhagic (5%), postinfectious (4%), connatal/miscellaneous/unknown (3%), myelomeningocele (2%), tumor/arachnoidal cyst/aqueduct stenosis (0%). Early shunting and poor functional status was associated with a higher risk for epilepsy. Epilepsy was not influenced by sex, shunt systems, or number of shunt revisions. Twenty-two (12%) of 182 patients developed epilepsy (generalized N=13, focal N=9) after intracranial shunting. Focal EEG abnormalities (N=16) were located mainly at the anatomical site of the shunt (N=14), but only three patients (2%) presented with focal seizures contralateral and focal EEG abnormalities ipsilateral to the site of the shunt. The presence of epilepsy was determined by the etiology of hydrocephalus rather than by surgical intervention. The incidence of postoperative epilepsy (12%) was low. Onset of epilepsy, clinical presentation of seizures, and EEG changes did not appear to be valid criteria for identifying shunt-related epilepsy. Thus, epilepsy as a complication of intracranial shunting might be overestimated in the literature.

Adolescent↗
PubMed1998

Fusiform dilatations of the internal carotid artery following surgery for pediatric suprasellar tumors.

Fusiform dilatations of the internal carotid artery (FDCA) represent a vascular complication following surgery for suprasellar tumors in children. In a long-term follow-up of 62 children we identified 7 children (11.3%) with a FDCA. In all children the FDCA was present within 15 months following surgery. It was not related to radiotherapy or a distinct histology. In 3 children the FDCA remained unchanged during the follow-up, in 3 children there was a progression and 1 child revealed a regression within 6 months. Clinically the FDCA was inapparent in all cases and not treated. In a follow-up study of an adult population who underwent surgery for suprasellar tumors no case of FDCA was encountered. Potential pathomechanisms and indications for treatment are discussed.

Adolescent↗
PubMed1998

Molecular analysis of childhood primitive neuroectodermal tumors defines markers associated with poor outcome.

PURPOSE: The diagnostic and prognostic significance of well-defined molecular markers was investigated in childhood primitive neuroectodermal tumors (PNET). MATERIALS AND METHODS: Using microsatellite analysis, Southern blot analysis, and fluorescence in situ hybridization (FISH), 30 primary tumors and six CSF metastasis specimens were analyzed for loss of heterozygosity (LOH) of chromosomes 1q31, 6q, 9q22, 10q, 11, 16q22, and 17p13.1 and/or high-level amplification of the c-myc gene. Experimental data were compared with clinical stage and outcome. RESULTS: LOH of chromosome 17p13.1 was found most frequently (14 of 30 tumors, six of six CSF metastasis specimens); LOH of chromosomes 10q, 16q22, 11, 6, 9q22, and 1q31 was observed in 20.6%, 20%, 14.3%, 12%, 10%, and 0%, respectively. Eight of 32 tumors and CSF specimens showed amplification of c-myc. All tumors with amplification of c-myc were resistant to therapy and had a fatal outcome (mean survival time, 9.3 months). Tumors that displayed LOH of chromosome 17p were associated with metastatic disease. The prognosis of these tumors was worse only when associated with amplification of c-myc. Three of three patients with LOH of 9q22 relapsed. CONCLUSION: In our study, amplification of c-myc was a poor-prognosis marker in PNET. LOH of chromosome 17p was associated with metastatic disease. Molecular analysis of primary tumors using these markers may be useful for stratification of children with PNET in future prospective studies. The other aberrations investigated were not of significant prognostic value, but may provide an entry point for future large-scale molecular studies.

Adolescent↗
PubMed1997

Medulloblastomas of the desmoplastic variant carry mutations of the human homologue of Drosophila patched.

Inactivating mutations in the PTCH gene, a human homologue of the Drosophila segment polarity gene patched, have been identified recently in patients with nevoid basal cell carcinoma syndrome. These patients are predisposed to various neoplasias including basal cell carcinomas and medulloblastomas (MBs). To determine the involvement of PTCH in sporadic MBs, which represent the most frequent malignant brain tumors in children, we screened for PTCH alterations in an unselected panel of 64 biopsy samples from 62 patients and four continuous MB cell lines, all derived from patients with sporadic MBs. Using single-strand conformational polymorphism analysis, we screened exons 2-22 and detected nonconservative PTCH mutations in 3 of 11 samples from sporadic cases of the desmoplastic variant of MB but none in 57 MBs with classical (nondesmoplastic) histology. In two of the tumors with mutations and in two additional desmoplastic cases, loss of heterozygosity was found at 9q22. These findings suggest that PTCH represents a tumor suppressor gene involved in the development of the desmoplastic variant of MB.

Adolescent↗
PubMed1997

High-resolution deletion mapping of chromosome arm 17p in childhood primitive neuroectodermal tumors reveals a common chromosomal disruption within the Smith-Magenis region, an unstable region in chromosome band 17p11.2.

Loss of heterozygosity (LOH) on chromosome arm 17p is the most common genetic aberration in childhood primitive neuroectodermal tumors (PNETs). To determine the frequency and extent of 17p deletions, 29 loci on 17p were investigated in 24 tumors by using restriction fragment length polymorphism (RFLP) and microsatellite analysis. LOH on 17p was found in 9 of 24 tumors. In all tumors with LOH, a continuous stretch from the telomere to chromosome band 17p11.2 was completely deleted, and no interstitial or terminal small-scale deletions were detected in the remaining 15 tumors. In four tumors with LOH on 17p, the chromosomal breakpoint was located between D17S953 and D17S805. To identify this deletion breakpoint on the cytogenetic map of chromosome 17 and to exclude uniparental disomy, we verified our data by using fluorescence in situ hybridization (FISH) analyses. By using two yeast artificial chromosome (YAC) clones that were positive for D17S689 and D17S953, the same breakpoint was confirmed in two specimens of cerebrospinal fluid (CSF) metastases by using FISH on interphase preparations. We demonstrate that, in most childhood PNETs with LOH on 17p, the breakpoint is close to, but not within, the centromere. It varies, and it occurs predominantly between the two markers D17S689 and D17S953, which is an unstable chromosomal region that is deleted or duplicated in the Smith-Magenis syndrome. Because LOH of 17p is associated with the formation of isochromosome 17q in the majority of PNETs, this study provides entry points to determine the molecular nature of this phenomenon.

Adolescent↗
PubMed1997

Pleomorphic xanthoastrocytoma: report of six cases with special consideration of diagnostic and therapeutic pitfalls.

BACKGROUND: Pleomorphic xanthoastrocytoma (PXA) is a rare clinicopathologic entity that occurs typically in young patients. Improved neuroradiologic techniques, especially gadolinium-enhanced magnetic resonance imaging (MRI), reveal a characteristic tumor appearance. METHODS: We present six cases of PXA operated on with unusual clinical course, elucidating different clinical implications. RESULTS: Two patients showed subsequent progression into a malignant glioma, one case was a primary anaplastic PXA. The latter case had not previously been reported in the literature. Increased mitotic activity seems to indicate a worse clinical course; whereas focal infiltration of the brain does not necessarily lead to malignant transformation. CONCLUSIONS: Surgical removal is the treatment of choice. A consequent follow-up is mandatory in order to detect a potentially malignant recurrence as early as possible and to select patients who need additional therapy.

Adolescent↗
PubMed1997

Odontogenic classification of craniopharyngiomas: a clinicopathological study of 54 cases.

Based on the striking histological similarity of craniopharyngiomas and some odontogenic tumours, we reclassified a series of 54 craniopharyngiomas (52 adamantinomatous and two papillary variants) according to the WHO classification of odontogenic tumours. Twenty-seven tumours (50%) corresponded histologically to calcifying odontogenic cyst. 13 tumours (24%) to ameloblastoma, and eight (15%) tumours showed features of both calcifying odontogenic cyst and ameloblastoma either within the same specimen or in specimens derived from different resections. Rare tumours included three cases resembling calcifying epithelial odontogenic tumour and one case resembling adenomatoid odontogenic tumour. No odontogenic counterpart could be established for papillary craniopharyngiomas. The two major subtypes, i.e. craniopharyngioma corresponding to calcifying odontogenic cyst and craniopharyngioma corresponding to ameloblastoma, did not differ in their basic clinical features. Our data confirm and extend the close histological resemblance between adamantinomatous craniopharyngioma and odontogenic tumours and cysts. Furthermore, although calcifying odontogenic cyst and ameloblastoma arising in the jaw differ in clinical presentation and outcome, our study did not reveal clinical differences for the corresponding subtypes of craniopharyngioma.

Adolescent↗
PubMed1996

Consensus: trigonocephaly.

Trigonocephaly mostly occurs in isolated synostosis of the metopic suture, but 10-20% of patients are affected by complex syndromes, and in 2-5% the condition is familial. Intracranial hypertension has been observed in a minority of cases, but is never severe. Surgery is performed mainly for cosmetic reasons, following the standard principles of craniofacial surgery. Complications are rare and satisfactory cosmetic results are generally obtained. There is little likelihood for recurrent deformity.

Craniosynostoses↗
PubMed1996

Recurrent bacterial meningitis.

UNLABELLED: To characterize recurrent bacterial meningitis in children, we reviewed the charts of all patients treated for more than one episode of bacterial meningitis at the Würzburg University Children's Hospital from 1980 to June 1995. Twenty-five children suffered 2-13 episodes of bacterial meningitis. Most patients were referred from other hospitals to our paediatric neurosurgical service. No immunodeficiency was found. In all patients, the cause of recurrent meningitis was an anatomical lesion with 13 intracranial defects including encephaloceles, skull fractures, Mondini dysplasias, neurenteric cyst, fibrous dysplasia, persistent craniopharyngeal duct, and 12 lumboscral defects with a dermoid cyst within the lumbosacral spine. A first episode of meningitis at school age did not exclude a congenital defect. In total, 84 episodes of meningitis were treated, a pathogen was isolated in 77%. The most common pathogen was Streptococcus pneumoniae, followed by Escherichia coli, Staphylococci and others. The pathogen isolated often gave a clue to the location of the defect. Personal history was often unrewarding and in some cases the search for the anatomical lesion required repeated imaging and explorative surgery. In 24 of 25 cases, final treatment of recurrent meningitis was by surgical intervention. CONCLUSION: In recurrent bacterial meningitis, excessive diagnostic and therapeutic procedures are indicated. An anatomical defect is a very probable cause.

Algorithms↗
PubMed1996

Molecular analysis of medulloblastomas occurring simultaneously in monozygotic twins.

UNLABELLED: We report male monocygotic twins with concordant desmoplastic medulloblastoma diagnosed at the age of 20 months. Both tumours were completely removed. As chromosomal loci 17p13 and 9q31 are frequently altered in medulloblastoma these regions were analysed in both tumours in detail using restriction fragment length polymorphism and microsatellite analysis. No common aberration was found. The c-myc gene on chromosome 8q21 was not amplified. CONCLUSION: Although a common genetic defect has not been found in our patients' tumours the clinical presentation supports the assumption of an inherited genetic predisposition to develop medulloblastoma in at least some cases.

Cerebellar Neoplasms↗
PubMed1993

Intracranial neurothekeoma (nerve-sheath myxoma). Case report.

Neurothekeoma is a benign cutaneous nerve-sheath tumor. The authors describe the case of a 16-year-old girl with a parasellar neurothekeoma that was successfully removed. Magnetic resonance imaging with gadolinium administration revealed bright enhancement of the peripheral portions and nonhomogeneous uptake in the central areas, which corresponded histologically to the vascular capsule and the myxoid center. It was concluded that: 1) intracranial neurothekeoma does exist, and 2) surgical resection appears to be the definitive therapy.

Adolescent↗
PubMed1992

Histiocytic tumor of Meckel's cave. An intracranial equivalent of juvenile xanthogranuloma of the skin.

We present the case of a 7-year-old boy who had a solitary mass within Meckel's cave that recurred 6 weeks after the initial resection. The histological, immunohistochemical, electron-microscopical, and molecular genetical features established the lesion's histiocytic nature. Our findings showed that it was closely related to juvenile xanthogranuloma, a benign lesion that usually occurs in the skin but has not yet been histologically confirmed in the brain. The present tumor is different from other intracranial histiocytic and xanthogranulomatous lesions.

Acid Phosphatase↗
PubMed1991

Movement of hemostatic clips from the ventricles through the aqueduct to the lumbar spinal canal. Case report.

The authors report a patient in whom rebleeding after operation for a left temporal arteriovenous malformation resulted in the dislocation of multiple hemostatic clips. Several clips, including a Yasargil aneurysm clip, were detected incidentally in the lumbar spinal canal. No clinical signs or symptoms were noted. Retrospectively, passage of the aneurysm clip through the aqueduct could be detected on computerized tomography scans performed to evaluate a series of epileptic seizures.

Cerebral Angiography↗