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M Samii

Publications and source records attributed to M Samii.

At least 19 recordsLinked to original sources
PubMed2006

Cavernous malformation of the internal auditory canal.

Cavernous malformations of the internal auditory canal are a rare clinical entity that, however, should be considered in the differential diagnosis of intracanalicular masses. Even though this type of malformation is usually associated with an evident gadolinium enhancement at MR examination, in some patients, like in this case, the signal characteristics may be not sufficiently specific to allow the correct preoperative diagnosis. Nevertheless, the clinical history, in particular, a rapid onset of cranial nerve deficits, lead to the suspicion of a vascular malformation.

Adult↗
PubMed2005

Fetal arachnoid cyst of the quadrigeminal cistern in MRI and ultrasound.

CASE: The authors report a fetus with an arachnoid cyst of the quadrigeminal cistern without hydrocephalus at 30 gestational weeks. DISCUSSION AND CONCLUSION: We reviewed the literature and could find only 62 reported cases of arachnoid cyst of the quadrigeminal cistern. We present a case without hydrocephalus diagnosed by combining ultrasound (US) and magnetic resonance imaging (MRI). The fetus, born by normal delivery, was followed up and did not show hydrocephalus for 1 year. This combined prenatal study, which uses US and MRI, helps in dispensing proper counseling to parents and assists the gynecologist and the neurosurgeon in the pre- and postnatal management of this condition.

Arachnoid Cysts↗
PubMed2005

Trigeminocardiac reflex during skull base surgery: mechanism and management.

BACKGROUND: We study the occurrence and management of the trigeminocardiac reflex (TCR) during neurosurgical procedures for lesions of the skull base. METHOD: Two hundred patients underwent neurosurgical procedures for various skull base lesions and were evaluated retrospectively for the occurrence of the TCR during surgery. This phenomenon was defined as the onset of bradycardia lower than 60 beats/minute and hypotension with a drop in mean arterial blood pressure of 20% or more due to intra-operative manipulation or traction on the trigeminal nerve. FINDINGS: Sixteen patients (8%) had a TCR intra-operatively (7 vestibular schwannomas, 5 sphenoid wing meningiomas, 3 petroclival meningiomas, 1 intracavernous epidermoid cyst). In all 16 patients with a TCR the postoperative courses presented no complications that could be directly related to this intra-operative phenomenon. CONCLUSIONS: Due to the intracranial course of the trigeminal nerve several surgical procedures at the anterior, middle and posterior skull base may elicit the trigeminocardiac reflex. Continuous monitoring of hemodynamic parameters allows the surgeon to interrupt surgical manoeuvres immediately upon the occurrence of the TCR. This technique is sufficient for the heart rate and the arterial blood pressure to return to normal levels without the necessity of additional anticholinergic medication.

Adult↗
PubMed2005

Surgical treatment of cerebellopontine angle meningiomas in elderly patients.

BACKGROUND: The aim of this study is to assess the morbidity and mortality of meningioma surgery in patients over 70 years of age harbouring a tumour at the cerebellopontine angle as one representative location of the posterior fossa in comparison with a matched group of young patients. METHOD: A retrospective analysis based on clinical charts, surgical records, histological records, imaging studies and follow up records was conducted to select patients over 70 years who underwent surgery for cerebellopontine angle meningiomas. Tumours with comparable size and location were matched with the younger group. FINDINGS: There were 421 meningiomas located in the cerebellopontine angle, 21 patients were older than 70 years (range 70-84). Median Karnofsky-Index at presentation was 80 (50-90), 16 patients had a physical status grading ASA 2 and 5 patients ASA 3. The average length of hospital stay was 22 days (7-99 days). The postoperative median Karnofsky score at time of discharge was 80 (50-90). The most common medical complication was postoperative pneumonia in 4 patients, among them 3 patients had lower cranial nerve disturbances postoperatively. There were 56 younger patients (mean age 52.4 years; range 24.5-69.75 years) with corresponding tumour size and location. Pre-op Karnofsky score was 80 (70-90), 53 patients were graded as ASA 2 and 3 patients as ASA 3. Length of hospital stay was 13.6 days (8-32 days). Post-op Karnofsky score was 80 (50-90). Among 5 patients with postoperative lower cranial nerve disturbances no patient had pneumonia postoperatively. There was no peri-operative mortality in either group. CONCLUSIONS: With modern neurosurgical techniques and neuro-anesthesia elderly patients with CPA meningiomas can be operated on with acceptable low morbidity and good neurological outcome but recovery from surgery lasts longer compared to younger patients. However, postoperative lower cranial nerve deficits in elderly patients may not be well tolerated compared with younger patients.

Adult↗
PubMed2005

Volumetric analysis of the growth rate of incompletely resected intracranial meningiomas.

OBJECTIVE: Intracranial meningiomas are mostly considered to be slow growing tumors. However, only a few previous reports provide information on the growth rate of these tumors. The aim of this study was to determine the growth rates of intracranial meningiomas after subtotal resection, analysing their relation to radiological appearance and histological features. Results are compared with our previous analysis of growth rates in incidental meningiomas . METHODS: The hospital charts, follow up records and imaging studies were reviewed in 36 patients with subtotally resected intracranial meningiomas. The tumor growth rates were determined by calculating the absolute and relative growth rates and the tumor volume doubling times. RESULTS: In the group of 33 patients with histologically verified grade 1 meningiomas, the mean absolute growth rate was 1.51 cm (3)/year, the median relative growth rate and tumor doubling time was 14.18 %/year and 5.228 years. In young patients annual relative growth rates were significantly higher. The median annual relative growth rate of meningiomas with calcification was significantly lower than in tumors without calcification. Also tumors with hypo- or isointense T (2)-signals on MRI revealed a lower growth rate. There was no significant difference between males and females. Histological studies revealed 22 meningiomas of a meningotheliomatous subtype, 8 fibrous and 3 psammomatous meningiomas. The comparison of growth rates between these subtypes did not show any significant differences. In atypical meningiomas (WHO grade 2), absolute and relative growth rates were significantly higher and tumor doubling times shorter. CONCLUSION: The majority of intracranial meningiomas are slow growing tumors, although the growth rates may vary widely even among benign grade 1 meningiomas. In meningiomas after subtotal surgical resection, the age of the patients seems to present a predictive factor for tumor growth in analogy to our previous observation in incidental meningiomas. Significantly higher relative growth rates were detected in younger patients. Gender does not seem to play a major role as a predictive factor. Radiological features such as calcification or T (2)-signal intensity may provide additional information to predict the growth potential of meningiomas. Close clinical and radiological observation should be performed in young patients harboring tumors with absence of calcification or high T (2)-signal intensities due to the higher growth potential in this patient group.

Adult↗
PubMed2004

Osteolytic intra-osseous meningiomas: illustrated review.

While bone invasion and hyperostosis are frequent phenomena in meningiomas, primary intra-osseous meningiomas are rare. With only 15 reported cases, the osteolytic form of primary intra-osseous meningiomas is most uncommon. Its occurrence in the skull base is an extra-ordinary exception. We have reviewed and categorized the pertinent literature on intra-osseus meningiomas with special emphasis on osteolytic tumours and discuss their clinical implications on the basis of a new case located in the petrous bone without contact with the meninges. It is concluded that due to their different clinical, radiological and pathological features, hyperostotic and osteolytic variants of intra-osseus meningiomas should be distinguished from tumours with soft tissue components and from en-plaque lesions.

Humans↗
PubMed2004

A model for intratumoural chemotherapy in the rat brain.

To achieve the best reproducibility in rat brain tumour models several injection techniques have been used. Although stereotactic cell injections have proved to be effective and reliable, they are expensive and time consuming. A new permanently implanted device is presented here. It allows precise cell delivery for best tumour reproducibility, and it can be left in place for future injections at the exact same location, such as intratumoural chemotherapy. A Teflon tube was mounted on a disc, inserted into the rat brain and sealed to the skull. The device was tested in two rat strains (Wistar and New Zealand Nude rats) with two different glioma cell lines (9L and C6). Rats were treated with placebo to determine if repeated treatments had an effect on the device placement, or if device-related morbidity was induced. Analysis of brain sections showed that the device path was always within the tumour. The device never moved or came off the scalp. Both Wistar rats and NZ nude rats tolerated the device well. No morbidity or mortality was observed, regardless of the presence of the device; no infections were seen. Biocompatible, non-irritating and well tolerated, such a device can be used for reproducible tumour cell injections and repeated intralesional delivery of drugs.

Animals↗
PubMed2004

Fetal allogeneic dopaminergic cell suspension grafts in the ventricular system of the rat: characterization of transplant morphology and graft-host interactions.

Experimental transplantation trials of fetal cells in Parkinson's and Huntington's disease or multiple sclerosis still require allogeneic graft material and raise questions of graft rejection and immunosuppression. Alternatively to the striatum, the lateral ventricles have been discussed as grafting site in Parkinson's and Huntington's disease although little is known of the specific immunology of the ventricular system. To address this question, 28 adult female LEW1.W rats received intraventricular allogeneic dopaminergic cell suspension grafts from E14 DA rat fetuses. Twelve animals with syngeneic grafts served as control. Immunohistochemical examination was performed with staining for MHC expression, microglia-macrophages, various lymphocyte subsets, dopaminergic neurons and astrocytes at 4 days, and 1, 3, 6, and 12 weeks after transplantation. In all animals, intraventricular transplants were found, which showed maturation and integration in the host parenchyma at the later time points. Animals with allogeneic grafts developed a vivid immune response with strong MHC class I expression and dense lymphocyte infiltrates. Surprisingly, this immune response subsided at 12 weeks and healthy grafts remained. These results indicate (1) that, in contrast to intraparenchymal grafts, a strong immune response to allogeneic fetal cell suspension grafts can be elicited by intraventricular grafting, (2) that a peculiar immunological role of the ventricular system has to be considered in further studies, and (3) that a vivid immune response to allografts in the brain may subside without graft destruction.

Animals↗
PubMed2004

The prognostic value of progesterone receptor status in meningiomas.

BACKGROUND: Meningiomas are known to recur frequently, and their longterm management remains controversial. Previous studies indicate that progesterone and its receptors can play a role in the recurrence of meningiomas, but the correlation between the presence of these receptors and patients' outcome is unclear. AIM: To conduct a retrospective analysis to investigate the prognostic relevance of progesterone receptor (PR) expression in meningiomas. METHODS: Five hundred and eighty eight meningiomas operated on over a period of 10 years were examined immunohistochemically to determine the PR status using monoclonal antibodies. Several factors including recurrence (mean follow up of 65 month), sex, tumour tissue consistency, location, vascularity, and en plaque appearance were analysed. RESULTS: PR status showed comparable values for men and women. World Health Organisation (WHO) grade II and III tumours had significantly fewer receptors than benign meningiomas. There was no significant correlation between PR status and recurrence rates in WHO grade I totally removed meningiomas. However, a combination of PR status and proliferation indices was shown to predict recurrence reliably. CONCLUSIONS: Together with routine histological evaluation, PR status can help to describe the biological behaviour of meningiomas. Only a combination of clinical and biological features can describe the behaviour of meningiomas, predict their recurrence, and help to devise more effective follow up strategies.

Adolescent↗
PubMed2003

The Ki-67 proliferation antigen in meningiomas. Experience in 600 cases.

BACKGROUND: Meningiomas are mostly benign tumours that can be cured by surgical resection. Because meningiomas tend to recur, long term management in patients with subtotal tumour resection remains controversial. Previous studies have shown that the proliferation potential of meningiomas by Ki-67 labelling indices (LI) might predict their natural history. The purpose of this study was to analyse the reliability of Ki-67-labelling index in predicting the behaviour of meningiomas, and to help the neurosurgeon in establishing better follow up criteria and long term management strategies for these patients. METHOD: From 1990 to 2000 1328 meningiomas have been operated in our Neurosurgical Department. A total of 600 tumours were examined immunohistochemically using the Mib-1 monoclonal antibody. Clinical charts of the patients including surgical, histological and follow up records, as well as imaging studies were analysed retrospectively. Ki-67 LI were correlated with neuroradiological findings, 3D volumetric studies, histological subtype, recurrence-free survival, grade of resection, consistency of tumour tissue, location, osseous involvement, en plaque appearance, vascularity and progesterone-receptor status. FINDINGS: Among the 600 patients analysed, there were 66% females (mean LI 3.8%) and 34% males (mean LI 5.7%), including 20 neurofibromatosis-type-2 (NF-II) patients with a mean LI of 5.2%. Histological grading revealed 91% WHO degrees I meningiomas (mean LI 3.28%), 7% WHO degrees II (mean LI 9.95%) and 2% WHO degrees III (mean LI 12.18%). Labelling indices in recurrent meningiomas increased from initial resection to a fourth local resection. A significant correlation between negative progesteron-receptor status and high tumour vascularity with high Ki-67 LI was seen. Ki67 was not a statistically significant predictor of survival time in totally excised WHO degrees I meningiomas. INTERPRETATION: Mib-1 is one important tool in addition to routine histological evaluation, but a combination of clinical factors and particularly the extent of surgical resection, along with the biological features of the tumour, should influence the decision of the neurosurgeon to the patient follow up.

Adolescent↗
PubMed2003

Surgical management of a meningioma in the retrosellar region.

Lesions ventral to the brainstem in the retrosellar and interpeduncular region are major challenges to the surgeon because of their location at great depth in the centre of the cranial base. We report the operative management of a patient with a meningioma in an unusual location, extending from the upper clivus, retrosellar and interpeduncular region into the suprasellar area up to the level of the foramen of Monro. A 41-year-old man presented with a 3-month history of progressive visual disturbance, episodic headache and signs and symptoms of endocrinological disturbance. Magnetic resonance imaging (MRI) studies showed a homogeneously enhancing tumour ventral to the brainstem with large cranio-caudal extension from the upper clivus to the suprasellar area. Operative removal was planned in two stages. First, through a right lateral suboccipital retrosigmoid craniectomy the caudal portion of the tumour at the upper clivus and prepontine region was removed. Second, the residual suprasellar part of the tumour was removed totally through a fronto-lateral craniotomy on the right side one week later. When a tumour is very large or involves different areas of the skull base, it is necessary to decide between removal in one stage, which requires a complex and time consuming skull base approach, or in multiple stages. Our case demonstrates how a retrosellar meningioma extending to the suprasellar region can be totally removed using two simple skull base approaches without the risk of compromise to venous drainage and without the need for extensive bone removal as described in other skull base approaches.

Adult↗
PubMed2003

Lateral Transmandibular Approach to the Skull Base in Children: Three Case Reports.

The choice of surgical approach to tumors of the cranial base in children is determined by strict criteria. The criteria include optimal visibility for the surgeon, minimal possible impairment of facial skull growth, and the preservation of motor and sensory nerve integrity. From 1993 to 1996, three children (6 years old, 22 months old, 6 months old, respectively) underwent surgery to resect cranial base tumors through a modified lateral transmandibular approach. In all three patients a preauricular incision with temporal and submandibular extensions was performed. After the mandible was prepared, an osteotomy was conducted cranially to the mandibular foramen. When the capitulum was temporarily disarticulated, wide access to the cranial base was provided and the tumors were resected. Two of these children were available for follow-up, and we continue to observe their development. Given the severity of their conditions, treatment yielded good results. Growth impairment of the mandible was corrected by the distraction osteogenesis technique.

Case Reports↗
PubMed2003

[Congenital teratoma of the skull base: case report of an interdisciplinary treatment].

Teratomas of the oropharynx are quite rare congenital tumors. Even more rare than oropharyngeal teratomas are those with additional intracranial extension. Reviewing the literature the prognosis of these cases has been poor. In the majority stillbirth or immediate postpartum death following respiratory obstruction is reported. We present a case of a congenital teratoma of the oral cavity with intracranial extension in a female neonate. After several intraoral tumor resections to establish secure airway in the postpartum period the total tumor resection had to be performed at the age of 6 month via a lateral transmandibular approach to the skull base. By using extraoral distaction devices the operation related microsomia of the mandible could be corrected at the age of 5 years. At 7 years follow-up the girl presented free of recurrence and without any neurological or functional deficits.

Female↗
PubMed2003

[Three-dimensional-segmentation of the spine with specially adapted tools].

Segmented 3-D data of the spine form the basis for various modern clinical applications. Among these, multisegmental image fusion, image registration and finite element modeling for biomechanical analysis are promising innovative tools capable of facilitating treatment decisions and optimization of individual therapy in the future. However, the complex anatomy of the spine and the often extensive degenerative deformation presenting in clinical practice, generally limit the application of fully automated segmentation. A newly developed software system is presented that meets the complex requirements for image segmentation of the spine through the use of specially adapted interactive tools that take account of its axial skeletal structure. Furthermore, a standardized protocol is introduced that combines the newly developed interactive tools (rotation transformation, warped dissection plane) and standard segmentation tools to permit rapid and accurate segmentation. To date, the software environment presented herein has been applied with success to the segmentation of cervical, thoracic and lumbar spine.

Algorithms↗
PubMed2002

The role of cerebral blood flow and cerebrovascular reserve capacity in the diagnosis of chronic hydrocephalus--a PET-study on 60 patients.

AIM: To investigate the clinical value of cerebral blood flow (CBF) and cerebrovascular reserve capacity (CVR) in the management of chronic hydrocephalus. Global cortical CBF and CVR in 60 patients (66 +/- 12 yrs) with chronic hydrocephalus were investigated before, one week (7 d) and 7 months (7 m) after shunting by 15-O-H2O PET (Siemens ECAT 951/31) at rest and after application of acetazolamide (1 g). After 7 months, clinical outcome was assessed according to Stein and Langfitt and patients were classified into responder (n = 31) and non-responder (n = 29). Before Surgery, responder had lower blood flow values compared to non responder (36 +/- 8 vs. 41 +/- 11 ml/100 ml/min; p = 0.04), whereas CVR was not different between outcome groups (33 +/- 10 vs. 41 +/- 8%; p > 0.05). After shunting, CVR in non-responder decreased from 41 +/- 8% to 32 +/- 5% (7 d), whereas in responder significant increases (p < 0.02) to 55 +/- 46% (7 d) and 54 +/- 31% (7 m) were observed. Regarding early individual changes in CVR, the majority (12/18; 66%) of non-responder had marked decreases in CVR-levels (< 30%), whereas clinical responder considerably improved in CVR (> 30%) in half of patients (7/14). Measurement of cerebral blood flow in chronic hydrocephalus might substantially contribute to selection of shunt candidates and neurological sequels may be rather related to early regeneration of the hemodynamic reserve.

Acetazolamide↗
PubMed2002

PET-studies in idiopathic chronic hydrocephalus before and after shunt-treatment: the role of risk factors for cerebrovascular disease (CVD) on cerebral hemodynamics.

AIM: To investigate the impact of cerebrovascular risk factors in idiopathic chronic hydrocephalus concerning cerebral hemodynamics and clinical outcome after shunting. Global cortical cerebral blood flow (CBF) and cerebrovascular reserve capacity (CVR) in 53 patients (67 +/- 11 yrs) were determined by 15-0-water-PET studies before and after administration of acetazolamide (1 g) prior (pre), one week (7 d) and seven months (7 m) after shunting. According to the prevalence of vascular risk factors (American subcommittee on reporting standards for cerebrovascular disease) patients were classified into a "low-risk" (n = 27) and "high-risk" (n = 20) group; patients with a history of stroke (n = 6) were separated. After 7 months, clinical outcome was assessed according to Stein and Langfitt. While CBF in "high-risk" patients prior to surgery was significantly lower in clinical responder compared to non-responder (32 +/- 5 vs. 42 +/- 15 ml/100 ml/min; p < 0.05), CVR was marginal in both outcome groups (< 30%). One week after shunting, CVR in responder of "high-risk" significantly increased (64 +/- 30 vs. 31 +/- 10% pre; p < 0.01). In "low-risk" patients, differences in CVR prior to shunting were found: CVR was lower in clinical responder than in non-responder (36 +/- 11 vs. 47 +/- 22% pre; p > 0.05) and deteriorated in non-responder (29 +/- 15% vs. 47 +/- 22 pre; p < 0.02) one week after shunting. Different peri-operative characteristics in global CVR regarding clinical response after shunting between both "risk-groups" were observed. Pathophysiological mechanisms upon clinical sequels after shunting in idiopathic hydrocephalus may not be unique.

Cerebrospinal Fluid Shunts↗
PubMed2002

Regional cerebral blood flow profiles of shunt-responder in idiopathic chronic hydrocephalus--a 15-O-water PET-study.

AIM: To find out if regional characteristics of cerebral blood flow (CBF) and cerebrovascular reserve capacity (CVR) may indicate shunt response in idiopathic chronic hydrocephalus. 11 patients with idiopathic chronic hydrocephalus (65 +/- 13 yrs) were followed-up within a year after shunting. Patients were classified into clinical responder (n = 5) and non-responder (n = 6) according to Stein and Langfitt. All patients had measurement of CBF and CVR with dynamic 15-O-water PET (Siemens ECAT 951/31) before and after application of acetazolamide (1 g). Regional differences between outcome groups were analysed with "statistical Parametric Mapping" (SPM99b; Wellcome Department, London, UK). Group differences were regarded as significant, when uncorrected p-value on voxel and on cluster level were p < 0.001 and p < 0.05, respectively. Regarding CBF distribution there was significantly reduced CBF in the frontobasal cortex in responder compared to non-responder (cluster level p = 0.026). In CVR, a variety of cortical regions showed significant decreases compared with non-responder: also in frontobasal cortex (on cluster level p = 0.009). However, most significant reductions were found in temporodorsal and limbic cortical regions (on cluster level p < 0.001). Preoperative hemodynamics displayed a regional profile of reduced CBF and CVR in patients with shunt improvement. Prospective studies for determining the accuracy of regional blood flow characteristics for outcome prediction are warranted.

Aged↗