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Biomedical subjects

H Suwa

Publications and source records attributed to H Suwa.

At least 91 records · Page 5Linked to original sources
PubMed1989

[Multiple spinal neurinomas without von Recklinghausen's disease: report of three cases].

Multiple spinal tumors are relatively rare and account for from only 1.2 to 9.5% of all spinal tumors. Half of the multiple spinal tumors are accompanied with von Recklinghausen's disease. Since March 1983, we have encountered 31 spinal tumors including 11 neurinomas, three of which were multiple and showed no manifestations of von Recklinghausen's disease. The incidence of multiple spinal tumors was 9.7% in our series. Altogether, 40 cases of multiple spinal neurinomas without von Recklinghausen's disease have been reported including our three cases. According to those 40 cases, much neurinomas occur 5 times more frequently in men than in women, and they are found predominantly in the lumbosacral region. In the present paper, we describe three cases of multiple spinal neurinomas, and compare the results of several neuroradiological examinations. Myelography was the most reliable method to determine whether or not the tumors were multiple. However, in cases where myelography was completely blocked out, other neuroradiological methods such as metrizamide-CT scan or MRI with Gd-DTPA intravenous injection were able to bring us information concerning multiplicity.

Adult↗
PubMed1989

[Carpal tunnel syndrome associated with long-term hemodialysis: case report].

Since Warren and Otieno reported carpal tunnel syndrome in patients on intermittent hemodialysis in 1975, a number of related reports have been published. However, there are few reports associated with neurosurgery about carpal tunnel syndrome in patients on long term hemodialysis. We reviewed this disease and reported our case. We treated a patient who complained of bilateral hand numbness and atrophy of the right thenar muscle. He had been suffering from chronic renal failure and had been treated with hemodialysis for ten years. We diagnosed carpal tunnel syndrome based on the findings concerning Tinel's sign, Phalen test, and the conduction velocity of the median nerve. We performed decompression surgery of the median nerve. However, although there was no recovery from thenar muscle atrophy, there was improvement of hand numbness. Histologically, amyloid deposits within the hypertrophic transverse carpal ligament on the right side, could be found but on the left side where the internal shunt had been made amyloid deposits were absent. The reason why patients receiving long term hemodialysis develop carpal tunnel syndrome is controversial, but it seems that beta 2 microglobulin may play an important role in developing carpal tunnel syndrome in hemodialysis patients. This was reported by Gejyo in 1985. There may be uremic and/or diabetic neuropathy in these patients, and these neuropathies may be responsible for the more rapid deterioration and poorer surgical results in carpal tunnel syndrome associated with hemodialysis than in idiopathic cases. It is most important that carpal tunnel syndrome has to be diagnosed early and that surgical decompression is performed while the disease is in its early stage.

Carpal Tunnel Syndrome↗
PubMed1989

[Usefulness and limitations of neuroradiological examinations in lumbar canal stenosis].

Since 1983, we have performed 434 spinal surgery operations. Among them are included 51 cases of lumbar canal stenosis. For these 51 cases, we performed several neuroradiological examinations, such as lumbar plain X-ray, myelography, metrizamide-CT scan (Met-CT) and magnetic resonance imaging (MRI). We discussed and examined the usefulness and limitations of such neuroradiological methods for diagnosis of lumbar canal stenosis. On myelography, these 51 patients were divided into three types; a complete block type with 29 patients, soy-beans type with 7 patients and strangulation type with 15 patients. Myelography could show the level of stenosis, but could give little information about the compressing factors, particularly in complete-block type. Met CT was performed in 37 cases. In both strangulation type and soy-beans type which had been shown through myelography, Met-CT could clearly demonstrate the subarachnoid space, and several structures around the lumbar spinal canal could be clearly identified. In cases which myelography revealed as complete-block type, we identified two subtypes. In the first type subarachnoid space was clearly demonstrated by Met-CT. The second type was comprised of those cases where Met-CT scan could not demonstrate subarachnoid space at all. In the former group, useful information about lumbar canal stenosis could be obtained, but, in the latter, information was scarce. MRI was performed on 21 patients. MRI clearly showed the anatomical relationship of disc, subarachnoid space, yellow ligament and hypertrophied bony structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Blue rubber bleb naevus syndrome.

An autopsy case of blue rubber bleb naevus syndrome (BRB-NS) is reported. There was the usual occurrence of cavernous haemangioma in the skin and intestine and cardiac involvement by a haemangiomatous lesion might have directly led to the patient's death. By light and electron microscopy, all the haemangiomatous lesions examined were cavernous with the exception of the cardiac tumour which was a mixed-vessel (capillary and cavernous) type of a haemangioma. These findings indicate that any vascular tumour-like lesions may occur in BRBNS. The principal combination of haemangiomas in the skin and intestine in BRBNS regardless of their type is the typical feature of this syndrome.

Female↗
PubMed1988

[Experimental study of the usefulness of evoked potentials in predicting the reversibility of the brainstem function following infratentorial epidural balloon compression].

With few warnings signs, posterior fossa mass lesions can affect life-supporting brainstem systems directly and cause a precipitous failure of vital functions. Consequently, a technique, by which brainstem dysfunction could be detected at its reversible stage, would have clinical value. Recently manly reports have suggested that the evoked potentials might be advantageous in assessing a developing brainstem dysfunction and might be a more sensitive or reliable detector of deteriorating neurological function than the physical or neurological signs. To explore this possibility, we recorded somatosensory evoked potentials (SEP) and brainstem auditory evoked potentials (BAEP) serially during inflation and deflation of balloons placed in the suboccipital epidural space of cats, as a model of an acutely expanding posterior fossa lesion. The results were correlated simultaneously recorded cardiovascular and pupillary function and with supratentorial and infratentorial epidural pressure. In this study, N1 of cortical SEP (CSEP), wave IV of BAEP, and wave III of short latency SEP (SSEP) were found to be useful parameters in predicting the electrophysiological reversibility. Experimental results were as follows: 1) As the infratentorial epidural balloon was expanded, CSEP, wave IV of BAEP and wave III of SSEP showed remarkable changes both in latency and in amplitude. Decrease in blood pressure and pulse rate preceded or developed at the same time as the apparent change in CSEP. Futher expansion of the balloon resulted in Cushing phenomenon and lability of blood pressure.2) As long as wave IV of BAEP remained, and decompression was started within 15 minutes after N1 of CSEP were completely suppressed, changes in SEP. BAEP and cardiovascular function were all reversible.2+ decompression. (ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

[Transthoracic approaches to the lesions of thoracic cord and thoracic vertebrae].

Experiences of transthoracic approaches to the thoracic cord lesions were reported. Since 1983, we have performed six transthoracic approaches to the thoracic lesions; one thoracic OPLL, one dumbbell-shaped neurinoma, two thoracic soft disc, one epidural metastatic tumor to thoracic vertebrae. From the viewpoint of surgical anatomy, the thoracic vertebrae show a physiological kyphosis and the subarachnoid space of the ventral site is narrower than that of the dorsal site. Due to such anatomical characteristics, the thoracic laminectomy for decompression is not so effective as in the cervical or lumbar region and a relatively small mass lesion can bring a paraplegic state. The lesion of the ventral site of the thoracic cord has been regarded as no man's land because of poor results of posterior approaches. Instead of posterior approaches, anterior or anterolateral approaches with transthoracic route have been adopted. In the present paper, we used transthoracic anterolateral approaches for four patients and anterior sternum-splitting approach for two patients. The operative procedures of the approaches were described in detail. By these approaches, we could treat four patients with favourable results but the result of thoracic OPLL was poor. The cause of this poor result seemed to depend upon the intraoperative compression of the thoracic cord. For the troublesome complication, we described the postoperative cerebrospinal fluid leakage into thoracic cavity with respiratory disturbance. Several devices to prevent such troublesome complication were discussed.

Adult↗
PubMed1987

[Experimental study of evoked potentials in predicting the reversibility of brain function following tentorial herniation].

Brainstem auditory evoked potentials (BAEP), somatosensory evoked potentials (SEP) and EEG were recorded sequentially in cat with mass-induced intracranial hypertension in correlation with mass volume, intracranial pressure (ICP), systemic blood pressure (BP) and size of the pupils. 1) As the intracranial pressure was raised by expansion of a supratentorial epidural balloon, suppression of cortical SEP (CSEP) and pupillary abnormality appeared first, EEG, waves IV and III of BAEP and wave III of short latency SEP (SSEP) were suppressed in this order. 2) As far as wave IV of BAEP remained and decompression was started within 30 minutes after peaks of CSEP completely suppressed, changes in P1 and N1 of CSEP were reversible. 3) Further raising of ICP was followed by loss of waves IV and III of BAEP and wave III of SSEP in this order. Simultaneously with loss of wave III in SSEP, systemic blood pressure dropped rapidly. By immediate balloon deflation after disappearance of wave III of SSEP, animals recovered from hypotension, but hardly from suppression in EEG, CSEP and BAEP. 4) Preservation of wave IV of BAEP indicated good improvement of pupillary abnormality even after removal of compression. These results suggest that for the patient with disturbed consciousness caused by supratentorial mass lesion, decompressive procedure should be started before wave V of BAEP and brainstem components of SEP disappear. EP monitor seems to be useful clinical method for preventing irreversible change of the brain in patients with coma caused by supratentorial mass lesions.

Animals↗
PubMed1986

[Technical problems in intraoperative monitoring of sensory evoked potentials].

Recent advances in both the equipment and the recording technique of sensory evoked potentials (EP) have brought high levels of versatility and reliability of objective measurement to the assessment of nervous system function. They have also allowed the use of intraoperative evoked potentials. The operating room, however, is usually considered a hostile environment, where various kinds of artifacts from surgical manipulation and generated by electrical armamentaria disturb electrophysiological recordings. Although several authors have reported on intraoperative EP monitoring, they have described few of the practical details of recording techniques. Having developed an intraoperative recording technique for evoked potentials over the past 3 years, we present the technical measures taken to overcome interference and obtain sufficiently stable and reliable EP recordings for intraoperative monitoring. All electrical equipment used in the operating rooms must, of course, be grounded securely. Even after grounding in the usual manner, however, artifacts appeared intermittently. The source was found to be a Mayfield-Kees three-pin head rest and a self-retaining retractor, both of which seemed to pick up electromagnetic radiation originating from electrocauteries and others. These artifacts could be minimized by grounding the head pins all each point of insertion into the patient's head and by use of a silicon-coated spatula rather than a metal one. In addition automatic artifact rejection by voltage overload sensing seems to be indispensable to eliminate the effect of extraneous mechanical and electrical interference which occur inevitably in surgical procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Stem↗
PubMed1986

[Technical details for recording trigeminal evoked potentials in the cat].

Experiments were undertaken to establish technical standards for recording of trigeminal evoked potentials (TEP) as a tool for assessment of the effectiveness of various therapeutic procedures for trigeminal neuralgia. Serial changes in the action potentials of the maxillary nerve and TEP were studied when parameters of electrical stimulation, namely, intensity and frequency, and position of electrodes were altered. The effects of use of muscle relaxants and change of body temperature of animals on TEP were also studied. On the basis of these experimental results, the technical details most suitable for TEP recording in cat were explored. The most distinct TEP was recorded under the following animal conditions and parameters: keeping rectal temperature between 37.5 degrees C and 38.5 degrees C, slackening with muscle relaxants, stimulating the infraorbital nerve with 10 volts of square-pulse electricity 5 times per second in short latency TEP and 2 times per second in long latency TEP, placing the active electrode on the vertex for short latency TEP and on the primary sensory area for long latency TEP. Eight positive peaks and three negative peaks were recorded under these conditions. The average and standard deviations of peak latency of potential from 10 cats were as follows: P 1, 0.67 +/- 0.04 msec; N 1, 0.89 +/- 0.07 msec; P 2, 1.35 +/- 0.10 msec; P 3, 1.89 +/- 0.08 msec; P 4, 2.43 +/- 0.26 msec; P 5, 3.17 +/- 0.15 msec; P 6, 3.36 +/- 0.21 msec; P 7, 5.02 +/- 0.39 msec; P 8, 6.07 +/- 0.35 msec; N 2, 10.4 +/- 1.15 msec; N 3, 18.5 +/- 1.74 msec.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

[Effects of thiopental on sensory evoked potentials in the cat].

Noninvasive electrophysiological evaluation with sensory evoked potentials would be of clear diagnostic and prognostic value in evaluating comatose patients with stroke or severe head injury. In order to protect the brain from such kinds of insults, barbiturate coma therapy has been employed and its effectiveness has been already established. However, in the barbiturate coma therapy, it is occasionally difficult to distinguish the pharmacological effect of barbiturate from the preexisting brain dysfunction caused by the underlying process of the disease. In adult cats, authors studied changes of sensory evoked potentials following cumulative intravenous administration of thiopental which is used clinically for barbiturate coma therapy. P1 and N1 of cortical SEP showed tendency of gradual decrease in amplitude. However, no significant changes occurred in latency by stepwise increment of thiopental dose. Changes in amplitude of P1 and N1 of cortical SEP preceded to the flattening on electroencephalogram. Around at the level of the concentration where EEG changes began, I-II interpeak latency of BAEP and latency of wave I of short latency SEP started to increase. BAEP and early components of SEP (I.II.III.IV) persisted even in by far the higher level of serum concentration of thiopental than that of clinical use. Furthermore, most of these parameters showed no statistically significant change neither in amplitude nor in latency. These experimental results suggest that sensory evoked potentials will provide us with useful information in the assessment of the brainstem function in patients under thiopental induced deep coma.

Animals↗
PubMed1986

[Implantable continuous epidural morphine infusion system for relief of chronic cancer pain].

Chronic cancer pain remains intractable by standard treatment in many patients and interferes with their mobility and independence. Epidural morphine infusion therapy is adopted for providing adequate analgesia in patients who are generally morphine independent and have intractable pain. A totally implantable pump system, Infusaid, has allowed continuous epidural morphine infusion without wound care or frequent percutaneous injections and with a potentially lowered risk of adverse reactions including respiratory suppression. Since December 1984, the authors have used this totally implantable drug delivery system for continuous epidural morphine infusion in two patients who had been suffering from chronic pain caused by pelvic cancer associated with metastatic and/or invasive lesions: Case 1: a 61-year-old man with rectum cancer; and Case 2: a 44-year-old man with colon cancer. Before system implantation, a therapeutic response to epidural morphine was confirmed by a one-shot test injection. Pain relief was evaluated by use of Visual Pain Analogue Scale Scores (VPASS). In spite of the presence of an artificial anus on the left abdomen in both patients and of pus discharge from a sacral infectious fistula on admission in Case 2, no infectious complication occurred in either case. Urinary retention developed after the implantation in Case 2, but this improved following the reduction of morphine concentration. No other adverse reaction was observed. In Case 1, the system was effective for 6 months until his death from advancing malignancy, and the patient was able to return to work three months after discharge.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Experimental study on the origins of far-field SEP to median nerve stimulation in the cat].

Results of various experimental and clinical studies on the origins of somatosensory evoked potentials (SEP) suggested that the far-field and early near-field potentials are generated primarily from sources within the dorsal column-medial lemniscal system. However, there are a few studies where direct depth recordings of SEP were performed and they were compared with surface-recorded SEP components. The purpose of this investigation is to determine the origins of somatosensory far-field and early near-field evoked potentials in cat by the analysis of distribution mode of surface-recorded SEPs, the comparison of depth recorded with surface-recorded SEPs and by the study of SEP changes caused by serial destruction of the structures relating to sensory pathway. A complex patterns of evoked potentials were recorded from cerebral epidural surface in cat by forelimb median nerve stimulation. The largest positive to negative slope was recorded from the epidural electrode on the sensory cortex contralateral to the stimulation. Five small positive potentials could be identified on the positive slope. We labeled these potentials as I, II, IIIA, IIIB, IV according to the report by Iragui-Madoz. The largest positive potential recorded from the VPL was coincident with the surface-recorded IIIB in latency at different interstimulus intervals. After transection of the midbrain-pons junction, IIIA remained unchanged, and the following waves disappeared. However, IIIA decreased in latency and markedly decreased in amplitude after transection of the pons at its rostral level. IIIA seems to be generated from the medial lemniscus at the level of osseous cerebellar tentorium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

[Effects of pentobarbital anesthetic induction on sensory evoked potentials in the cat].

During the last decade, noninvasive electrophysiological tests with sensory evoked potentials have rapidly blossomed into useful clinical tools. They have been studied in large groups of normal subjects and in patients with a wide variety of neurologic diseases. Almost all experimental animal studies on sensory evoked potential, however, have not been undertaken under sufficient consideration on the effects of drugs used for induction into anesthesia on evoked potentials. In order to use evoked potentials as a tool for assessing neurological function in animals, it is necessary to known the effect of anesthetic agents on evoked potentials. Pentobarbital, Somnopentyl, is one of the drugs most commonly used for induction into anesthesia is animal experiments. Authors have attempted to study the long term effects of pentobarbital on evoked potentials. Intramuscular administration of anesthetic dose of pentobarbital was followed by prolongation of 11 and III waves of SEP and I-II interpeak latency of BAEP. Latency of N1 of SEP was also prolonged. On electroencephalogram, amplitude have increased and frequency have got slower after pentobarbital administration. These electrophysiological changes persisted over 5 hours after pentobarbital administration. These results suggest that in some studies on animals the residual effect of agents used for induction into anesthesia must be taken account for analysis of data obtained.

Anesthesia↗