Biomedical subjects

M Samii

Publications and source records attributed to M Samii.

At least 181 records · Page 10Linked to original sources

PubMed1995

Hearing preservation in bilateral acoustic neurinomas.

Bilateral acoustic neurinomas are found in almost all patients with neurofibromatosis 2 (NF2). With better knowledge of the disease and development of diagnostic procedures, an increasing number of patients have been detected at an early stage of the disease. Preservation of hearing in these cases has become more feasible. Between 1979 and 1992, 110 acoustic neurinomas in 74 NF2 patients have been resected in this department. All tumours but 11 were completely removed. In 11 cases deliberate subtotal tumour removal was performed: bilaterally in one deaf patient for brainstem decompression, and unilaterally in nine patients with the aim of hearing preservation. In seven of these nine cases hearing was preserved. The total rate of hearing preservation was 36%. Considering only those patients with good preoperative hearing and small tumours, the rate of hearing preservation was 58%. Facial nerve preservation was 92%. Nerve reconstructions were performed in cases of facial nerve damage, with good results in most of the cases. The importance of early detection of the disease and early removal of tumours is stressed. Surgical decision making based on the author's personal experience in dealing with these cases is discussed, and some cases are illustrated.

Adolescent↗

PubMed1995

Esthesioneuroblastomas with intracranial extension. Proliferative potential and management.

A total of 15 patients with esthesioneuroblastomas were treated between 1978 and 1992 at the Neurosurgery Department, Nordstadt Hospital, Hannover. In 9 cases, the tumors invaded the anterior cranial fossa. One patient died before any surgical intervention. Eight tumors were operated by a combined paranasal and subfrontal approach. Gross total tumor removal was achieved in all cases. Apart from anosmia, the only postoperative complication was transient mental changes in one case. Immunohistochemical analyses with MIB 1 monoclonal antibodies, directed against recombinant parts of Ki-67 antigen, were performed to estimate the proliferative potential of the esthesioneuroblastomas. Most of the tumors showed high proliferating cell indexes, which ranged from 3 to 42% (mean, 16%). The proliferating cell index with MIB 1 showed a correlation with postoperative outcome, although this was not statistically significant. Esthesioneuroblastomas can be totally removed surgically. The proliferating cell index may reflect histologically the biological behavior of tumor. Long-term follow-up is mandatory, and immunohistochemical studies may be of help in predicting outcome.

Adult↗

PubMed1995

Surgical treatment of trigeminal schwannomas.

A total of 27 patients with trigeminal schwannoma were treated between 1982 and 1992 at the Neurosurgery Department of Nordstadt Hospital. Twelve cases of solitary schwannoma without any family history or physical stigmata of neurofibromatosis were included and form the basis of this study. There were four women and eight men (mean age 44 years) in this series. Duration of symptoms ranged from 2 months to 6 years. The most frequent symptoms were either pain or numbness of the ipsilateral hemiface. The surgical approach was chosen depending on the tumor type. Tumors that belonged to Type A (five cases), which were predominantly in the middle fossa, were approached using a transsylvian method; Type B (one case), which presented predominantly in the cerebellopontine angle, was operated on via a retrosigmoid suboccipital craniectomy; Type C (five cases), which were dumbbell-shaped extending into both the middle and posterior fossa, were removed via a combined temporal craniotomy-presigmoidal method; and in Type D (one case), in which tumor was primarily extracranial with intracranial extension, an infratemporal extradural approach was undertaken. There was no operative mortality or long-term disability in this series. The follow-up period ranged from 12 to 60 months; during that time magnetic resonance imaging revealed tumor recurrence in two cases after 12 and 48 months, respectively, and these were excised again. An additional 178 cases collected from the world literature are also reviewed and analyzed.

Abducens Nerve↗

PubMed1995

Surgical treatment of jugular foramen schwannomas.

Sixteen patients with schwannomas of the jugular foramen were operated on in the Department of Neurosurgery of the Nordstadt Hospital in Hannover, Germany, between 1986 and 1992. Patients with neurofibromatosis were excluded. The records of the 16 patients were retrospectively reviewed. There were five women and 11 men (mean age 43 years) with a symptom duration ranging from 6 months to 20 years (mean 5 years). The predominant symptoms were hearing loss, hoarseness, and cerebellar symptoms. Computerized tomography (CT), magnetic resonance (MR) imaging, and angiography were performed in all 16 patients. Depending on the radiological and surgical features, the tumors were classified into four types: Type A, a tumor primarily at the cerebellopontine angle with minimal enlargement of the jugular foramen (eight cases); Type B, a tumor primarily at the jugular foramen with intracranial extension (two cases); Type C, a primarily extracranial tumor with extension into the jugular foramen (one case); and Type D, a dumbbell-shaped tumor with both intra- and extracranial components (five cases). A retromastoid suboccipital craniectomy was performed for Type A tumors, and a combined cervical-mastoidectomy for Types B, C, and D. Total tumor removal was achieved in all cases. There was no operative mortality. Postoperative complications were cerebrospinal fluid leakage in one patient and mastoiditis in two patients. The follow-up period ranged from 12 to 42 months (mean 22 months). All patients were alive at the last follow-up review, and CT and/or MR imaging showed no tumor recurrence.

Adult↗

PubMed1995

Applications of MR angiography in head and neck pathology.

MR angiography is a useful examination in the area of head and neck pathology when correctly applied and tailored to a specific clinical problem. Of the cases presented in this article, the most common application is evaluation of vascular invasion or displacement to aid in surgical planning of tumor resection. Applications to evaluation of vascular thrombosis or dissection, assessment of tumor vascularity, and visualization of variant vascular anatomy and acquired vascular disease were also demonstrated.

Adolescent↗

PubMed1994

Management of occult intrasacral meningocele associated with lumbar disc prolapse.

Occult intrasacral meningocele is an uncommon condition that may produce chronic low back pain, sciatica, and bladder dysfunction. We describe a patient suffering from low back pain and radicular symptoms, in whom multimodality radiological examinations showed an intrasacral meningocele and a lumbar disc prolapse. The protruded disc was considered to be the cause of the clinical symptoms in this patient rather than the meningocele. Surgical removal of the protruded disc was performed without interference with the meningocele. Postoperatively there was recovery of the preoperative deficits. Clinical and radiographic findings in occult intrasacral meningocele are discussed and criteria for differential diagnosis with disc prolapse are stressed.

Humans↗

PubMed1994

Involvement of spinal nerves in neurofibromatosis.

Spinal tumors are a frequent form of manifestation of neurofibromatosis. Out of 171 patients, who have been operated on over a ten years period on spinal tumors, 7 patients had neurofibromatosis (4.1%). A total of 9 operations were performed, removing 20 spinal tumors. Three patients had multiple neurofibromas. Half of the neurofibromas had a dumbbell configuration with a larger extraspinal extension. In three patients a family history of neurofibromatosis and typical dermatological signs were evident. Two cases will be selected and the basic concept regarding treatment and the risks involved will be discussed.

Adolescent↗

PubMed1994

Occult dysraphism in adulthood: clinical course and management.

We present a series of 23 patients with dysraphic malformations and adult onset of symptoms (4 meningoceles, 19 spinal hamartomas). Mean age at presentation was 39 +/- 21 years (range 23-67 years). Patients were followed up for a mean period of 19 months (range 0.5-68 months). Only patients with progressive neurological disease were operated on (3 meningoceles and 16 spinal hamartomas). The remaining patients were treated conservatively and continue to be observed clinically. Two of three patients operated for meningoceles improved without recurrence of symptoms. Patients with spinal hamartomas could be divided into two groups according to their main symptom: paraparesis (group A, n = 8) or pain (group B, n = 11). Malformations in group B were typically associated with a tethered cord and tended to be more complex than in group A. The majority of patients in group A showed better long-term results than patients in group B, due to their considerably lower rate of recurrence.

Adult↗

PubMed1994

Indication, technique and results of facial nerve reconstruction.

160 patients with various intra- or extracranial pathologies were treated by microsurgical facial nerve reconstruction at Nordstadt Neurosurgical Clinic between 1978 and 1993. Facial nerve reconstruction was accomplished along the anatomical course of the facial nerve from its origin at the brainstem, within the mastoid, at the stylomastoid foramen and within the face. Mostly, reconstruction was indicated because of nerve discontinuity (n = 61), whereas facial nerve reanimation with a donor nerve such as the contralateral facial nerve or the ipsilateral hypoglossal nerve was indicated in 99 cases of loss of a proximal nerve stump. Depending on the site of the lesion reinnervation started at 5 to 15 months postoperatively lasting for 2 to 3 years with overall satisfactory results. 69% of all the patients regained good symmetry on rest, complete eye closure equivalent to House-Brackmann-Score III: Patients with complete failures either suffered of non-related diseases such as cancer leading to death before the estimated time of recovery or were exposed to radiation or received facial nerve reconstruction after long-standing facial deficit and marked muscular atrophy. The indication of the adequate method depends on the clinical course with or without preexisting facial paresis, on considering the intraoperative state of the facial nerve, the identification and microsurgical preparation of adequate nerve stumps, as well as on the adaptation techniques and the postoperative guidance of the patient. We conclude that facial nerve reconstruction by transplantation at either site of the nerve course or by reanimation with a donor nerve are effective and reliable procedures of treatment leading to satisfactory functional and cosmetic results.

Adolescent↗

PubMed1994

Facial nerve reconstruction in neurofibromatosis 2.

Between 1979 and 1989, 13 patients with neurofibromatosis 2 underwent reconstructions of the facial nerve after removal of bilateral acoustic or facial neurinomas. Seven patients received hypoglossal-facial nerve anastomosis, and five received sural nerve grafting in the cerebellopontine angle. End-to-end anastomosis and intracranial-intratemporal sural grafting were performed for one patient each, respectively. Re-innervation was seen in all cases. The results were good in 11 cases. Two patients presented with poor results due to development of neurinomas close to the site of the nerve reconstruction. The importance of reconstructive surgery in patients with neurofibromatosis is stressed. The problems regarding failure of re-innervation in some cases and difficulties in their management are discussed.

Adolescent↗

PubMed1994

Stereotactic endoscopic treatment of colloid cysts of the third ventricle.

In order to avoid invasive procedures (transfrontal, transcallosal) in the surgical treatment of colloid cysts the stereotactic aspiration technique was introduced by Bosch, Rähn and Backlund in 1978. The viscosity of the intracystic colloid and the displacement of the cyst away from the aspiration needle are possible reasons for unsuccessful aspiration. GT-guided stereotactic endoscopic technique gives the opportunity to fenestrate the cyst wall under direct visual control. After CT-guided stereotactic puncture of the right lateral ventricle with the foramen of Monro as target a steerable endoscope is introduced and the foramen of Monro is passed. The wall of the cyst is fenestrated and coagulated by means of monopolar (or laser) coagulation. Using this technique we have treated four patients with colloid cysts. Immediately postoperatively all of them were relieved of their complaints and have been symptom-free for a mean follow up period of twelve months. Studies of cerebrospinal fluid flow patterns, performed prior to and every six months after the endoscopic intervention, confirmed a remarkable reduction of foraminal obstruction.

Adult↗

PubMed1994

Flexible endoscopes in treatment of colloid cysts of the third ventricle.

Goals of treatment of colloid cysts of the third ventricle are relief of foraminal obstruction and prevention of recurrence. Both goals are perfectly met by microsurgical removal from a transfrontal-transventricular or a transcallosal approach, however, with both approaches there are serious related complications. CT-guided stereotactic aspiration of colloid cysts is a simple method with low risk. Nevertheless, treatment failures as well as a considerable late recurrence rate are reported. The CT-guided stereotactic endoscopic technique gives the opportunity to widely open the cyst wall and aspirate the cyst fluid under direct visual control, thereby reducing the risk of the procedure and due to broad opening of the cyst wall refilling becomes less likely possible.

Adult↗

PubMed1994

Surgical results of 100 intramedullary tumors in relation to accompanying syringomyelia.

During the period from 1977 to August 1992, 100 intramedullary tumors in 94 patients were operated on in the Department of Neurosurgery at the Nordstadt Hospital in Hannover, Germany. Of these, 45% presented with associated syringes. A syrinx was more likely to be found above (49%) than below (11%) the tumor level. In 40%, a syrinx could be identified above and below the tumor level. Ependymomas and hemangioblastomas were the most common tumor types to be associated with syringes. Astrocytomas tended to demonstrate syringes less often. Regardless of histology, the higher the spinal level, the more likely a syrinx was encountered. In general, the presence of an associated syrinx favored the resectability of the tumor, because it indicated a displacing rather than an infiltrating tumor. Patients with syringomyelia tended to recover from surgery sooner. However, surgical results and long-term prognosis were not influenced significantly by an associated syrinx. The most important factor determining long-term outcome was the preoperative level of neurological function. We propose that factors independent of the tumor, disturbances of cerebrospinal fluid and extracellular fluid flow in particular, have major roles in the pathogenesis of syrinx formation associated with intramedullary tumors.

Adolescent↗

PubMed1994

Cranial granular-cell tumor of the trigeminal nerve. Case report.

Granular-cell tumors are exceedingly rare neoplasms in the central nervous system. Their histogenesis has been a subject of longstanding controversy but substantial findings support the current theory of a Schwann cell origin. Other recent histopathological studies point to an astrocytic origin in those tumors which arise from the cerebral hemispheres. A case of a granular-cell tumor arising from the trigeminal nerve is described. The origin, clinical course, radiological features, and treatment of such unusual intracerebral tumors are discussed.

Adult↗

PubMed1994

[Dural arteriovenous fistula as a rare cause of intracerebral hemorrhage].

Dural arteriovenous fistulas are rare vascular malformations presenting with very different clinical signs, depending on the pattern of venous drainage. Retrograde leptomeningeal venous drainage is significantly correlated with a progressive neurological presentation. A case of a dural arteriovenous fistula with cortical venous drainage is presented. The draining vein was frankly aneurysmal dilated. Rupture of this venous aneurysm caused an intracerebral hemorrhage. The venous varix and the hematoma were microsurgically resected and evacuated.

Arteriovenous Malformations↗

PubMed1993

Chronic compression of the cervical myelon as complication of anterior interbody fusion (AIF): neurological improvement after late anterior decompression. Case report.

Severe neurological deficits directly related to intraoperative injury of the spinal cord and the nerve roots is a rare complication of anterior interbody fusion (AIF) in cervical spondylosis. A case of radiculopathy and Brown-Séquard Syndrome caused by a bone fragment following AIF in which a late anterior decompression and fusion of the cervical spine was performed four years after the initial operation is presented. Immediate relief of the radicular pain, improvement of the spasticity, and better sphincter control could be achieved. Therefore, patients with chronic anterior compression of an incomplete spinal cord injury after AIF may benefit from a late anterior decompression and fusion.

Female↗

PubMed1993

Solitary brain metastasis 13 years after removal of renal adenocarcinoma.

We report a case of a patient who developed a single brain metastasis to the cerebellum 13 years after removal of a renal adenocarcinoma. The cerebellar metastasis was removed twice due to local recurrence one year after the first operation. The patient is alive and doing well 18 months after the second neurosurgical procedure. The metastasis was not associated with any other evidence of disease. Brain metastasis may present many years after removal of kidney adenocarcinoma and when not associated with other evidence of disease their operative treatment may carry a good prognosis.

Adenocarcinoma↗

PubMed1993

Somatosensory evoked potentials and intracranial pressure during chronic dilatation of an artificial extraparenchymal space-occupying lesion in cats.

Somatosensory evoked potentials (SEP) and intracranial pressure (ICP) were studied in cats, suffering from a chronic space-occupying lesion produced by enlargement of an epidural balloon over the left sensomotory cortex. Our study shows that latency alterations of SEP are not dependent on the degree of ICP. Additionally, the results obtained demonstrate that chronic space-occupying lesions cause continuous prolongation of SEP latencies, probably produced by atrophy of the compressed tissue. Regarding the clinical importance of SEP measurements, we concluded that they are not suitable for estimating the degree of ICP. However, they are useful to evaluate tissue damage caused by mass effects in the acute and chronic phase of various space-occupying processes.

Animals↗