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Biomedical subjects

M Samii

Publications and source records attributed to M Samii.

At least 235 records · Page 13Linked to original sources
PubMed1988

Revascularization of nerve grafts: an experimental study.

The time course of revascularization of grafted nerves, and the possible dependence of this revascularization on the length of the graft are two related questions that are addressed. Survival of Schwann cells in the nerve graft and a timely revascularization must be seen as a precondition for an optimal regeneration process. The revascularization process after different postoperative intervals is demonstrated in the sciatic nerve of rabbits by the use of microangiography, with Roentgen-positive water-soluble contrast medium. The third postoperative day is the earliest point in time for revascularization of the autologous graft from surrounding tissues. On the fourth postoperative day, a hyperemia with extension to all sides of the intraneural vessel system exists that still persists on the fifth and sixth days. In one experimental group, revascularization was allowed to occur only in a longitudinal direction. Revascularization under these conditions proved to be poor, slow, and obviously dependent on the length of the graft. Survival and subsequent function of free autologous nerve grafts may depend on the diameter of the grafts and the quality of the recipient site, but not on the length of the grafts, when timely revascularization from the surrounding tissues is present.

Animals↗
PubMed1988

Bone imaging as an aid for the diagnosis of osteopoikilosis.

An unusual case of osteopoikilosis was found in a 52-year-old black woman. The rather large diffuse focal increased densities involving the ribs, spine, and pelvis as seen in the roentgenograms were believed to represent metastatic bone lesions. The normal nuclide bone images helped revise the diagnosis to osteopoikilosis. Early recognition of osteopoikilosis would have prevented the patient's apprehension and the extensive work-up for the primary tumor.

Bone Neoplasms↗
PubMed1987

Stable-xenon-CT: effects of xenon inhalation on EEG and cardio-respiratory parameters in the human.

The effects of inhalation of a 33% Xenon-O2 mixture over a period of 5 minutes on EEG and cardio-respiratory parameters were studied in 18 human volunteers. This dosage is similar to that used clinically in Xenon-CT studies. In 4 cases no EEG power change was observed during the study. In the 14 other subjects EEG variations were seen. The most prominent change was an increase in beta EEG power. No change was observed in theta and delta EEG power. The findings seem to correlate with the early induction (excitation) phase of an anaesthetic. Hyperventilation was observed before the study and increased during the Xenon inhalation. Blood pressure remained stable while the heart rate tended to decrease a little. All these changes disappeared rapidly following the termination of the Xenon inhalation. The effects are minimal and should not reduce the clinical value of CBF measurement using the Xenon-CT method.

Administration, Inhalation↗
PubMed1987

EEG changes during five minutes of inhalation of a 33% xenon-O2 mixture.

The effects on the EEG of inhalation of a 33% Xenon O2 mixture over a period of 5 minutes were studied in 18 human volunteers. This dosage is similar to that used in xenon CT studies. In 4 subjects no EEG changes were observed during the study. In the 14 other subjects, EEG variations were detected, the most prominent of which was an increase in beta power. No change was observed in theta and delta power. These findings seem to support an early induction (excitation) phase of anaesthetics. All changes disappeared rapidly following the termination of xenon inhalation. The effects reported are minimal and should not impair the clinical value of CBF measurements using the xenon CT method.

Administration, Inhalation↗
PubMed1986

[Experience with the inhalation of a 33% xenon-(stable-)oxygen mixture in relation to a new method of measuring local cerebral circulation].

We describe a new non-invasive method for measuring local blood flow in the brain. Xenon (stable)-nl CBF-CT-method has been used in our clinic for the first time in Europe. It is superior to all other methods, such as 133Xenon, SPECT and PET in terms of anatomical accuracy and its resolution. We describe the method and its side effects. Inhalation of Xenon in sub-narcotic doses (33% for five minutes) produced no significant complications. Of 95 examinations, 74 were free of any incidents. The most common side effect was euphoria. The method appears to be suitable for general clinical use.

Cerebrovascular Circulation↗
PubMed1985

Possibility of the excision of aneurysms in the vertebrobasilar system followed by end-to-end anastomosis for the maintenance of circulation.

Microsurgical techniques have revolutionized the perspectives of neurosurgery. Vascular neurosurgery in particular has only shown real progress since the evolution of such techniques. The management of large fusiform aneurysms had always been more problematic than that of the usual aneurysms. Clipping was either insufficient to occlude the whole neck or too extensive to include a significant part of the parent vessel and its important branches. Several alternative methods were therefore developed to redress the problem and included proximal occlusion, coating and wrapping, induction of intralaminal thrombosis with a variety of substances, and balloon catheter occlusions; however, they have all proved to have limited success. Aneurysmorrhaphy (excision of the aneurysm and reconstruction of the vessel wall) has also been described. In 1978 Dolenc reported excision of a fusiform aneurysm along with the adjacent vessel wall and an end-to-end anastomosis, either directly or by interposing a short arterial graft, in two cases of peripheral middle cerebral aneurysms, and in one aneurysm arising from PICA. This communication deals with two cases of large fusiform aneurysms of the vertebrobasillar territory, one from PICA and another from P2P3 Segment of the posterior cerebral arteries. These aneurysms were excised and the parent vessel reanastomosed to restore its continuity as seen at surgery and on postoperative angiography. The results have been favourable. The technique is recommended for the elimination of a large fusiform aneurysm that cannot be safely or successfully clipped, provided the parent vessel is lax or mobile enough to permit direct reanastomosis despite the slight shortening of vessel length.

Adult↗
PubMed1985

Malignant teratoma of the optic nerve: case report.

An unusual case of a malignant teratoma of the right optic nerve with extension into the chiasm is presented. The preoperative diagnosis was difficult to establish. Complete removal of the lesion with postoperative irradiation was carried out. Eight months after the operation, the patient developed subarachnoid metastases by the cerebrospinal fluid pathway as well as systemic metastases and died. No local recurrence of the tumor was seen at autopsy. The therapeutic possibilities for these lesions are discussed.

Adult↗
PubMed1985

Management of seventh and eighth nerve involvement by cerebellopontine angle tumors.

Microsurgical techniques have made a significant contribution in the advancement of surgery. Since then, the field of neurosurgery has made great and rapid strides. Neurosurgeons now venture through the deep and delicate regions of the brain where they dared not venture only a few years ago. In particular, the morbidity and mortality of surgery in the CPA has seen a progressive decrease. This presentation deals with 200 consecutive tumors in the CPA operated on using microsurgical techniques during the last 6 years. One hundred sixty-seven (83.5%) of them were acoustic neuromas (which included 12 patients with bilateral tumors). Of the remaining 33, there were 21 meningiomas, 10 epidermoids, and 2 angioblastomas. Preoperative investigation has been aimed at arriving at a diagnosis which is as exact as possible in order to plan the operative strategy. All patients, ranging in age from 16 to 84, have been operated upon in the lounging position (with the necessary precautions) through a unilateral suboccipital craniectomy. The basic surgical technique, irrespective of the tumor, is to decompress it from within in order to relieve its tension and pressure on surrounding nerves, vessels, and the brain stem. The structures which are only compressed are spontaneously relieved of compression. This helps define their full anatomic course. Having been identified, they are protected from damage. The most adherent points between tumor and nerves are recognized and handled last under direct vision when there is sufficient space to allow manipulation of the tumor. In the rare event of the facial nerve being interrupted, nerve graft procedures are attempted during the same operation. Our experience with the technique of intracranial-intratemporal facial nerve grafting has yielded excellent results. The cochlear nerve lacks a Schwann cell cover in the CPA and is more prone to being affected, either by tumor processes or surgical manipulation. Of our 167 acoustic nerve tumors, 60% were larger than 3 cm in diameter. The two important factors with regard to predicting the preservation of the seventh and eighth cranial nerves are tumor size (less than 3 cm) and preoperative hearing loss (less than 40 dB). The preservation of facial nerve function after tumor removal was achieved in 87.8% of patients. The facial nerve was preserved in all patients with other tumors. With regard to hearing ability the overall result of preservation of function was achieved in 27.6%. However, when a low hearing loss (less than 40 dB) and small tumor size (less than 3 cm) are taken into account, the preservation was as high as 58%.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1985

[Angiomatous malformation of the inner auditory canal with the leading symptoms of vertigo and tinnitus].

A case of a rare arteriovenous malformation in the internal auditory canal is reported. It caused unilateral tinnitus, facial weakness, trigeminal hypesthesia, and vertigo with lateropulsion. The audiological and otoneurological findings together with air-cisternography a CT scan had indicated an intrameatal tumor. An extended trans-temporal exposure of the internal auditory canal demonstrated an angiomatous lesion compressing the adjacent seventh and eighth cranial nerves. It could be removed safely by a second-stage lateral suboccipital approach to the cerebello-pontine angle.

Diagnosis, Differential↗
PubMed1984

[Results of 110 microsurgical acoustic neuroma operations].

We report our experiences in 110 cases of microsurgical removal of acoustic neurinomas. The historic development, the chances of preservation of the facial nerve and hearing function and the mortality risks are described in detail, hereby stressing the advantages of the lateral suboccipital approach in microneurosurgery.

Audiometry, Pure-Tone↗
PubMed1984

[100 microsurgical tumor excisions in the cerebellopontile angle with special reference to the preservation of hearing function].

A report is given on the experience gained in the microsurgical treatment of 100 tumours of the cerebellopontine angle - among them 78 neurinomas - under special consideration of the preservation of the audition. The advantages of the lateral suboccipital access in connection with the possibility to open the internal auditory meatus are pointed out. The problems regarding the treatment of bilateral neurinomas of the acusticus in Morbus Recklinghausen are discussed under a theoretical and a practical angle. Pre- and post-operative audition of the patients is subdivided according to the size and histology of the tumours.

Audiometry, Pure-Tone↗
PubMed1984

Thermocoagulation of the dorsal root entry zone for the treatment of intractable pain.

The authors report the results of DREZ thermocoagulation in 35 patients since March 1980. This technique was applied not only in patients with deafferentation pain after brachial plexus avulsion, but also for postamputation phantom limb pain and pain caused by injury to the spine and spinal cord, by peripheral nerve lesions, and by multiple sclerosis. Independent of etiology, the duration of the pain syndrome, and the quality and projection of the pain, the overall results have been satisfactory and long-lasting.

Brachial Plexus↗
PubMed1984

Facial nerve grafting in acoustic neurinoma.

The introduction of the operating microscope has strongly influenced our surgical possibilities for preserving and reconstructing the facial nerve in tumor surgery in the cerebellopontine angle as well as in the internal auditory canal. In 1975, we introduced a new method for facial nerve reconstruction in the cerebellopontine angle. Since then, we have operated upon 20 patients using this technique of intracranial-intratemporal nerve graft; 15 of these have been done directly after the removal of the acoustic neurinoma. Of these patients, 12 have been followed over a period of 9 to 87 months. A sural nerve graft 4 to 5 cm in length was placed between the central stump of facial nerve at the brain stem and the distal end of facial nerve in tympanal or mastoidal course after total removal of the acoustic neurinoma. The results, demonstrated in this paper, are highly encouraging. It is recommended that this operative technique be included in the entire concept of microsurgery in the cerebellopontine angle.

Adolescent↗
PubMed1982

[Neuro-otologic diagnosis of tumors of the posterior cranial fossa--delayed auditory evoked potentials also on the opposite side].

We report on patients from a combined neurosurgical neuro-otological group (N = 36) in whom we were able to show that in tumours of the posterior cranial fossa, the acoustic evoked potentials may be -normal on the healthy side; -delayed on the healthy side, too, and improved post-operatively; -delayed on the healthy side postoperatively only. The relevant constellation of findings is mainly determined by the localization and size of the tumour, and hence by compression of the brain stem with or without occlusive hydrocephalus in the fourth ventricle. The observations suggest that mere comparison of the latency differences of both sides does not exhaust the possibilities of ERA; and, rather, that it is necessary to record the responses from both sides over the usual audiometric range of sound intensity and to correlate them both to the norm latencies and to the individual audiometric image.

Adult↗
PubMed1981

Operative treatment of lesions in the region of the tentorial notch.

After a description of the topographic anatomy, the different approaches to the tentorial notch and the details of technique are illustrated by a few examples. The pterional approach permits surgical treatment of lesions in the supratentorial region of the anterior and middle third of the tentorial opening. Any approach to the infratentorial region can be enlarged and improved by incising and stitching back the free margin of the tentorium. The medial occipital approach is appropriate for space-occupying lesions situated medially in the ascending portion, that is in the posterior third of the free margin of the tentorium. Infratentorial tumours in the cerebello-pontine angle and in the prepontine region, with extension into the tentorial notch, are best treated through the lateral suboccipital approach. A subfrontal infrachiasmatic procedure is indicated in the case of suprasellar lesions with parasellar extension into the tentorial notch, if the anatomy of the optic chiasm allows it. The location of any particular lesion may call for a combination of different approaches.

Brain↗
PubMed1981

[The indications, technique and results of facio-facial anastomosis (author's transl)].

On the basis of our experiences with facio-facial nerve anastomosis in 62 patients, with and without various plastic procedures on skin and muscles, we can definitely say that results are not as satisfactory as those of nerve suture or grafting when performed as a direct operation on the facial nerve. This is obvious because only 50% of the fibres of the intact (donor) nerve are available for anastomosis. Consequently a facio-facial anastomosis should only be considered in those cases where a direct operation on the facial nerve is technically impossible or where a previous operation on the lesion has not produced the desired improvement and the anastomosis is done as an additional procedure. To achieve the most satisfactory result we would recommend performing plastic procedures on skin and muscle at the same stage. With this technique we were able to secure satisfactory results in 21 cases.

Aged↗
PubMed1981

[Contribution to the surgical treatment of haematoma and hygroma in adults (author's transl)].

Among thirty cases of chronic subdural hematoma and hygroma in patients between 16 and 78 years of age, nine were found on the left side, ten on the right side and eleven were bilateral. The diagnosis was made in all cases by computer assisted tomography. Surgical treatment consisted in evacuating the subdural collection of fluid through two or three enlarged burr-holes, resection of the membranes were accessible through the burr-hole, irrigation of the subdural space and its subsequent drainage. The drain was left in postoperatively until the draining fluid became clear or the subdural space was dry. In one case there was a superficial intracerebral hematoma which obsorbed spontaneously. One patient with a subdural empyema required craniotomy. Only four out of ten patients who were comatose pre-operatively survived. Out of the 30 patients, 24 had a satisfactory postoperative outcome.

Adolescent↗