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Biomedical subjects

L Merienne

Publications and source records attributed to L Merienne.

At least 55 records · Page 3Linked to original sources
PubMed1992

[Stereotaxic laser interstitial thermotherapy. A new alternative in the therapeutic management of some brain tumors].

Laser Interstitial Thermo Therapy (ITT) is a new procedure which has been performed only a few times in our department as well as in foreign services. The aim of an ITT is to increase the temperature of a tumoral target which has been perfectly determined stereotactically. In the center of the target, i-e at the extremity of the laser fibre, temperature reaches 80 degrees 90 degrees C and creates a coagulation necrosis. At the periphery of the target, temperature must be 41 degrees-43 degrees C so as to create a selective lesion of the pathological tissue due to proteinic and enzymatic denaturation. The authors present their experience based on 8 patients who underwent an ITT between June 1990 and October 1991. A stereotactic determination of the tumor is first performed; then two routes are determined for the laser-fibre (Nd-YAG 1.06 microns, fiber diameter: 400 mu) and for the thermic electrode. The ITT itself is performed a few days later (P = 3-5w, time: 800-1200 seconds). Laser heat effects are monitored with MRI controls (H5, H24, D8 then monthly). The authors insist on the importance of a long follow-up so as to be sure of the complete inocuity of such a treatment. It is the only way to broaden and develop laser-ITT procedures as therapeutic alternatives for certain deep-seated intracerebral tumors.

Brain Neoplasms↗
PubMed1992

[Use of Nd-YAG laser in intracranial endoscopy. An initial experience in stereotaxy].

The authors report on four cases of intra-ventricular lesions surgically treated by endoscopic laser-therapy in stereotactic conditions. Two colloid cysts of the third ventricle, one arachnoidal cyst responsible for with an intracranial hypertension and an intraventricular meningioma were treated with such a procedure. The laser beam was used as a surgical knife on cystic lesions and to vaporize the meningioma. The laser coupled with an endoscope add to the comfort given by direct visualization the precision of surgical instrument the effects of which are perfectly controllable in areas where surgical traumatism must be avoided as much as possible.

Arachnoid Cysts↗
PubMed1992

Traumatic aneurysms of the internal and external carotid arteries. One case and a review of the literature.

The case of a female patient with two traumatic aneurysms diagnosed by serial angiography is reported. The first aneurysms, located on the orbito-frontal branch of the left anterior cerebral artery, was removed. The second aneurysm involving the right middle meningeal artery was treated by endovascular embolization. The causes and physiopathology of such lesions are reviewed. The frequency of traumatic cerebral aneurysms has been reduced by the routine use of computed tomography. Aggressive treatment of these aneurysms is advocated because of their natural history.

Adolescent↗
PubMed1991

[Stereotaxic irradiation of 46 cerebral angiomas. Analysis of the angiographic results 2 and a half years after treatment].

Between May 1986 and March 1987, 46 small and medium sized cerebral arteriovenous malformations (AVM) were treated by radiosurgery in Paris. The stereotaxic coordinates of the lesions were determined according to the method of J. Talairach and the total radiation dose was delivered on spherical or ovoid target volumes with minibeams of 18 MV photons, using the technique developed by Osvaldo Betti. A review of the cases was undertaken in december 89. Twenty-one patients had previously been treated by embolization and/or surgery (46.6%). During the 25 to 40 months follow-up there were only 2 recurrences of bleeding (4.3). Control arteriography was performed in 38 cases (38/46 = 82.6%). There were thirteen cases of total disappearance of the AVM (13/36 = 34.2%), 17 incomplete obliterations (44.7%) and 9 (23%) arteriographies failed to show any radiological improvement. Eight patients had no arteriographic follow-up: 2 of them experienced a recurrence of bleeding and died before the planned arteriography, 1 was lost to follow-up and 5 patients refused control arteriography. A multidisciplinary team is needed to study the shape, the volume, the hemodynamic features of the AVM and the dosimetry in order to attain the best definition of the target volume and of the dose distribution. It seems that when the target volume included the nidus and the venous collector, follow-up arteriography results were satisfactory. Even though the optimum dose is yet to be determined, our results imply that a dose distribution allowing for 25 grays at the periphery of the AVM (isodose 70%) seems sufficient provided that the target volume is included within the 25.00 Gy isodose curve.

Adolescent↗
PubMed1990

1.32 microns Nd:YAG laser during neurosurgical procedures experience with about 70 patients operated on with the MC 2100 unit.

The authors present their clinical experience with 1.32 microns Nd-YAG Laser. After a series of experimental studies which demonstrated the adaptability of such a wavelength to central nervous surgery, they used such a Laser during current neurosurgical procedures. The MC 2100 unit combines two wavelengths 1.32 microns and 1.06 microns, and two emission modes: continuous wave (c.w.) and pulsed. This Laser has been used during 70 procedures: 54 supra-tentorial, 8 infra-tentorial, 5 intra-spinal, 3 intra-orbital, 600 microns and 400 microns fibers were preferred in most cases, either with a telescopic light handpiece or- less often--with a focussing handpiece. The quality of vaporization--close to that of CO2 Laser- and of haemostasis-close to that of 1.06 microns Nd-YAG Laser-makes this 1.32 microns wavelength very suitable for neurosurgery. The manoeuverability due to the optic fibers is most interesting. Furthermore, such a Laser should have in the near future large applications in stereotactic and/or endoscopic neurosurgery.

Brain Neoplasms↗
PubMed1990

Effects of 1.32-micron Nd-YAG laser on brain thermal and histological experimental data.

Considering that the 1.32-microns Nd-YAG laser should have physicothermal properties close to those of the CO2 laser, a series of experiments were conducted on rat cortex (N = 51). Three laser wavelengths were compared: CO2 laser (10.6 microns), 1.06-microns Nd-YAG, and 1.32-microns Nd-YAG lasers. For each shot, temperature measurements were recorded with an infrared thermographic videocamera. The digitized signals were figured as thermal profiles and temperature developments. Ninety-five shots were correctly studied and analyzed: CO2, N = 29; 1.06-microns Nd-YAG, N = 20; 1.32-microns Nd-YAG, N = 46. The histological lesions produced by these three lasers were compared on animals killed 24 hours (N = 20), 8 days (N = 20), and 30 days (N = 5) after the laser impacts. For equivalent densities of energy, the depth of cortical necrosis was comparable for the CO2 laser (200-250 microns) and the 1.32-microns Nd-YAG laser (210-260 microns) whatever the date of death; the 1.06-microns Nd-YAG laser shots were responsible for much more important damage (400-550 microns). Because of its important absorption in water and nervous tissue, the authors consider the 1.32-microns Nd-YAG laser most suitable for neurosurgery, particularly because it is conducted through optic fibers, and therefore is easy to handle during neurosurgical procedures.

Animals↗
PubMed1988

[Stereotaxic ventriculocisternostomy in the treatment of triventricular obstructive hydrocephalus. Apropos of 23 cases].

UNLABELLED: During the period January 1975-October 1987, we performed stereotactic ventriculocisternostomy (V.C.S.) on 23 patients (13 M., 10 F.; age: 11-73 years, m: 33). Sometimes used as an isolated therapeutic procedure, V.C.S. may also follow stereotactic biopsies using Talairach's methodology. Serial stereotactic biopsies were performed in 15 out of 23 patients showing 11 tumoral lesion, two arachnoïdal cysts and two cryptic vascular malformations. Eight patients presented with an isolated aqueductal stenosis. Among the 12 non tumoral patients, seven had very large triventricular hydrocephalus (6 with a retroclival dilatation of the third ventricle) and 5 showed significant dilatation. Of the 11 tumoral patients, 7 had significant ventricular dilatation (1 with a protrusion of the floor of the third ventricle) and 4 with modest dilation. V.C.S. is done by creating an opening (diameter: 5-6 mm) in the floor of third ventricle with a fine forceps introduced through a tubular guide (diameter: 2.45 mm). The percutaneous double oblique transfrontal trajectory (drill-hole: 2.5 mm of diameter) passing through the foramina of Monro, avoids superficial and deep vessels visualised on the previous Stereoscopic Tele-Angiographic and Ventriculographic study. A systematic verification of the V.C.S. patency is made intraoperatively by injection of iodine contrast medium into the third ventricle. RESULTS: (non tumoral patients: 12) (m follow-up: 4 years): two patients needed a ventricular shunt after 3 and 1 months respectively, the first one because of an associated communicant hydrocephalus, the second because of a post-operative meningeal infection. Long-term clinical and CT-Scan follow-up showed that complete resolution (7 cases) or partial (2 cases) improvement of symptoms and signs was not accompanied by normalization of ventricular size, even though the dilatation was significantly reduced in 8 cases and to a lesser extent in 2. RESULTS: (tumoral patients: 11) (m follow-up: 3 years). Hydrocephalus was reduced in 6 cases and remained unchanged in 5. Two patients needed a ventricular shunt 2 years after the V.C.S.: 1 patient, because of a tumoral recurrence involving the region of the fenestration, the second patient because of adhesive arachnoiditis following reoperation for suspicion of recurrence, though this was found to be granulomatous inflammation. Two patients died as a result of their tumors at 2 and 6 years. CONCLUSION: Stereotactic V.C.S. is the treatment of choice for triventricular obstructive hydrocephalus even when there is no retroclival dilatation of the floor of the third ventricle.

Adolescent↗
PubMed1985

[Neurosurgery with a CO2 laser. Evaluation of 61 operations].

The authors present the results of their over two years experience with CO2 Laser neurosurgical unit. They explicit the indications and the technical data followed during intra-cranial (N = 44), intra-spinal (N = 12) and intra-orbital (N = 5) procedures. Meningiomas, neurinomas and adenomas are the best indications for tumoral CO2 Laser neurosurgery. In other respects sterilization and cranialization of aeric sinuses are simplified by the use of CO2 Laser: it assures vaporization of the mucosa and carbonization of the walls more easily than an electric coagulator. At last the use of CO2 Laser for dissection and removal of intra-orbital tumors is quite demonstrative. Thus owing to its physical and thermical qualities CO2 Laser is often a very useful, sometimes irreplaceable, apparatus: provided that its indications are precise and rigorous.

Adolescent↗
PubMed1982

[Treatment of various dyskinesias by intermittent thalamic stimulation].

Abnormal movements or dyskinesias are associated with hyperpathia and hyperalgesia in a number of conditions such as post amputation jumping stumps pseudothalamic syndromes following cerebro vascular accidents and in some cases of demyelinating diseases. Intermittent electrical stimulation of the specific sensory nucleus of the thalamus (I.T.S.) controls at the same time pain and dyskinesias with the same long lasting effect. In some cases where dyskinesias are associated with sensory deafferentation, but not with chronic pain or hyperpathia, the same positive effect of thalamic stimulation on the control of abnormal movements is achieved while in other cases of tremor or dyskinesias without sensory deafferentation such as parkinsonism, intention tremor etc.. the efficacy of I.T.S. is nil. Hence, discriminative sensory deaffrentation is the common link between the cases of tremor or dyskinesias that use to respond to I.T.S. which is up to now the only therapy of proven efficacy in such conditions.

Amputation Stumps↗
PubMed1981

[Transformation of body scheme caused by thalamic stimulation. Thalamic stimulation for painful phantom limb (author's transl)].

Intermittent stimulation of the parvo cellular portion of the nucleus ventralis posterolateralis (VLP) was able to control both pain and phantom limb phenomenon. The authors insist upon the transformation of the "body scheme" caused by an operation which does not alter the somesthesic function. The sensorial delusion of a phantom limb is probably related to an insufficiency of sensitive information at thalamus level.

Electric Stimulation Therapy↗
PubMed1980

Control of dyskinesias due to sensory deafferentation by means of thalamic stimulation.

Intermittent stimulation of the parvocellular portion of the nucleus ventralis posterolateralis (V.P.L.) by means of chronically implanted electrodes and stimulus generator was performed in 124 patients for the control of chronic intractable pain. Among these, 11 showed spontaneous abnormal movements within the painful area: 6 post amputation "jumping stumps"; 4 pseudothalamic syndromes and 1 Von Benedikt's syndrome following a cerebrovascular accident. Electrical stimulation of the V.P.L. was able to control both pain and abnormal movements in all cases. The technique was applied with an equally good result in a case of choreoathetotic syndrome without pain but with severe sensory disturbances following a demyelinating process. Attempts made to control action tremor, parkinsonism and other dyskinesias not associated with sensory deafferentation in 12 cases failed. The same mechanism seems to be responsible for pain and dyskinesia in cases of sensory deafferentation, and thalamic stimulation might work as a substitute for sensory information delivered to the nucleus ventralis posterolateralis.

Amputation, Surgical↗
PubMed1978

[beta2-Microglobulin determination's estimation in cerebrospinal fluid (author's transl)].

beta2-Microglobulin levels were determined the serum and CSF by radioimmunoassay in various patients from departments of neurology and neurosurgery. Simultaneously a study of CSF protein levels was done. In normal subjects, there is a good correlation between blood and beta2m levels. In patients with pure subarachnoid hemorrhage, the beta2m was always found elevated in the CSF. In tumors of the nervous system, the number of cases studied is yet too small to allow any conclusion.

Beta-Globulins↗
PubMed1977

[Pleural and intraspinal tumor with hypercalcitoninemia].

The authors report a case of probably ectopic secretion of calcitonin in a 35 year old woman suffering from a malignant tumour in a double intra- and extra-spinal form. Hormone levels returned to normal after complete excision of the tumour, in which it was impossible to demonstrate the presence of calcitonin despite a very marked secretory appearance by electron microscopy. Study of the literature concerning the secretion of calcitonin by malignant tumours indicates the high degree of contradiction concerning the origin and the significance of increased radio-immunological levels of this hormone, which it is not possible to use without criticism as a "marker" of carcinomas.

Adult↗
PubMed1976

[Present state of pain surgery].

This report presented to the Société de Neurochirurgie de Langue Française is based on 34 years of unique practice in neurosurgical management of pain; during that long period the author and his associates have collected an unusually large experience in almost every field of neurosurgical management of pain; they have improved or fully devised several new techniques which allow them to ground an appreciation of the procedures still worthy to be used in various pain syndromes. The first part of the report deals with "Cybernetics of pain". This rather long chapter is based both on classical data and personal observations on man during and following operations, meant to relieve pain. Though supporting HEAD and HOLMES, theory on Control of protopathic by epicritic Stimuli, the authors consider that the type of pain associated with noxious stimulation as representative of just one among other types of pain, not induced by nociception and not associated with protection reflexes. Sensory deafferentation as can be produced by amputations, herpes zoster, dorsal column or medullary lesions, cannot be included in Sherrington's scheme of psychical mechanisms associated with protection reflexes and yet is responsible for most of the chronic unbearable and often intractable pain. Moreover, an important modulation of pain as such depends on conditioning, on inherited and acquired patterns of behaviour and on a multiplicating factor which is provisionally named "algogenic neurosis". The fact that an intact nucleus ventralis posterolateralis is a necessity for a "no pain status" tends to prove that this thalamic nucleus acts as a major inhibiting relay on the pain integrating system and for several additional reasons is the level of integration of epicritic versus protopathic stimuli in case of true nociception...

Analgesia↗