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B Turak

Publications and source records attributed to B Turak.

31 records · Page 2Linked to original sources
PubMed1998

High-power diode laser in neurosurgery: clinical experience in 30 cases.

BACKGROUND: High-power semiconductor diode lasers were recently introduced and have been tested in ophthalmology and general surgery. These lasers are attractive from the practical and economical standpoint, and have enough power to perform most surgical procedures. They could replace other surgical lasers such as CO2, argon, 1.06 microm, and 1.32 microm Nd-YAG lasers for many applications in neurosurgery. We report our initial experience with the first available 0.805-microm surgical diode laser, the Diomed 25 (Diomed, Ltd, Cambridge, U.K.) in a series of 30 patients. METHODS: The diode laser was evaluated during surgical resection of various types of central nervous system tumors in 30 patients. It was used free-hand in 27 patients in contact and non-contact, continuous wave (cw) and pulsed modes, and during ventricular endoscopy in three patients. Average time of laser use during a procedure was 248 seconds. Output power ranged from 1 to 25 watts, with an average power per patient of 2.64 to 15.5 watts (mean, 8.78 watts). Total energy delivered ranged from 65 to 11,051 joules per patient. RESULTS: Using 600- or 400-microm non-contact optic fiber, well pigmented tumor tissue hemostasis was obtained at cw 3 to 10 watts with a defocused beam, whereas vaporization required 10-25 cw or pulsed watts with a focused beam. Soft and tough tissue section could be obtained using a sculpted cone-shaped (600-300 microm tip) contact fiber at 7-10 cw watts after fiber tip charring. Because of the deeper penetration of 0.805-microm light in non-pigmented tissues, non-contact mode is not recommended for white matter or poorly vascularized tumors. The contact mode was not efficient on very soft tissues such as edematous brain parenchyma. The contact fibers proved to be very fragile because of heat generation. CONCLUSIONS: The high power diode laser proved to be efficient for hemostasis, section and vaporization, using contact and non-contact modes, at different output powers. Economical and ergonomical advantages of this new generation of surgical lasers may cause them to replace other surgical lasers such as argon, CO2, and Nd-YAG lasers, mostly for tumor surgery.

Adolescent↗
PubMed1998

[The place of radiosurgery in the treatment of hypophyseal adenoma].

Since 1984, the neurosurgical team of Sainte-Anne Hospital in Paris has taken in charge almost 750 patients for linear accelerator radiosurgery. But only a small percentage of them were harbouring a pituitary tumor. That is why the present paper is based mostly on literature data. Pituitary adenoma radiosurgery (RS) is a second intention therapeutic method. It should be recommended only after failure of medical and/or surgical treatment. Two main methods can be used: linear accelerator-radiosurgery and Cobalt-60 gamma unit. Both procedures provide equivalent results in terms of dosimetry, accuracy and clinical data. Results of various series presented in recent and updated literature have been studied and analysed. They show and confirm the efficiency of radiosurgery on tumor and hormone secretion controls, with few cases of pituitary insufficiency. However, results were disappointing concerning visual disorders, particularly if visual dysfunction and impairment existed before radiosurgery. All authors agree nowadays on different points: a) indications: invasive adenomas, with an incomplete resection, or adenomatous recurrences, b) contraindications: tumoral size > 20 mm, distance to visual pathways < 5 mm, c) imperative precautionary measures: less than 8 Gray must be delivered on visual pathways, less than 40 Gray on oculomotor nerves. In some cases, stereotactic fractioned radiotherapy may be an alternative treatment for large tumors close to visual pathways.

Adenoma↗
PubMed1998

[Intracavernous extension of hypophyseal macroadenomas: infiltration or invagination?].

Frequency of intracavernous invasion by a pituitary adenoma varies from 9% to 40% depending on the publications. Without putting off the possibility of true intracavernous invasion, it seems less frequent than evocated on CT-Scan and/or MRI data. We studied 153 files of pituitary adenomas operated upon recently: 72 prolactinomas (47.3%), 30 GH-secreting adenomas (19.7%), 7 corticotrop adenomas (4.6%), 44 non secreting adenomas (28.3%). 108 patients (70.4%) harboured a macroadenoma (diameter > 10 mm). A suprasellar expansion was seen 90 times on CT-Scan and/or MRI views. 19 times (17.7% of macroadenomas, 12.5% of the whole series) MRI evocated an infiltration of one or both cavernous sinuses (CS). Such data were found 3 times before 1991, 16 times since 1991, i.e. since MRI is systematically performed preoperatively. Except in two patients who respectively presented with a large intraorbital or temporal expansion, we have not been able to confirm the reality of the intracavernous invasion. We think that most of CT-Scan or MRI data of so-called intracavernous invasion correspond in fact to a compression or to a fingerglove invagination of the medial wall of the CS. In fact, anatomical studies by Harris & Rhoton (1976) and by Taptas (1990) demonstrated that such an invagination of the medial wall exists in almost one third of normal pituitary glands. These data must bring up to much carefulness when considering a possible pathological CS invasion by a macroadenoma. Therefore, it should be thoroughly assessed with anatomoradiological and radio-surgical correlations.

Adenoma↗
PubMed1998

[Controversies in the management of operated pituitary macroadenomas].

BACKGROUND AND PURPOSE: Complete resection of a pituitary adenoma is feasible in almost 50 to 70% of cases. Dealing with the remnant is still controversial. Three positions can be discussed: second stage operation, radiation therapy, clinical and radiological follow-up. METHODS: Among 108 pituitary macroadenomas operated on during the last 10 years, 54 patients (50%) with partially removed tumors were studied. Three cases best illustrating the evolution of these remnants are reported. RESULTS: Late MRI performed 4 to 6 months postoperatively is more valuable than early MRI in the evaluation of these remnants, which can remain stable for a long period of time without any adjuvant treatment. CONCLUSION: MRI should be performed 4 to 6 months postoperatively. Rather than performing radiation therapy systematically for asymptomatic patients, these patients should be followed up at regular intervals and treated only in case of regrowth of the tumor.

Adenoma↗
PubMed1997

Chronic intractable epilepsy associated with a tumor located in the central region: functional mapping data and postoperative outcome.

Out of 57 patients operated for intractable epilepsy of the central region, 8 harbored an indolent glioma (7 dysembryoplastic neuroepithelial tumors, 1 ganglioglioma). Mapping of the sensorimotor area with depth electrodes implanted for stereoelectroencephalographic exploration demonstrated no or abnormal motor responses after low-frequency stimulation, and variable sensory responses to high-frequency stimulation, suggesting reorganization of the sensorimotor cortex representation around the tumor and absence of functional tissue within the neoplastic volume. After lesionectomy (3 cases) or corticectomy including the tumor (5 cases), 6 (75%) patients were seizure-free (class I of Engel) at the time to follow-up. No permanent motor or sensory deficit was observed in 6 cases. In 2, a mild facial (in 1) and arm (in 1) deficit persisted. It is concluded that the resection of intrinsic low-grade tumors associated with long-standing epilepsy and located in the central region can be associated with excellent seizure outcome and no or minimal postoperative deficit because of functional reorganization of the sensorimotor cortex.

Adolescent↗
PubMed1997

[Stereotaxic technics and clinical neurosurgery].

Stereotactic methodology developed at Sainte-Anne Hospital Center from 1947 is based on the application of a simple spatial geometry-the Talairach Ac-Pc reference system-to the cranial volume and the identification of any anatomical structure or brain lesion within this volume. Now upgraded with modern imaging techniques, this methodology is the ground for multiple applications in functional as well as lesional neurosurgery and is now a a part of the daily neurosurgical practice at Sainte-Anne Hospital. Stereotactic procedures include three steps: first, the identification of one or several target-volumes through stereotactic imaging acquisition: CT, MRI and conventional stereoscopic angiography; second, the image treatment on a dedicated workstation for stereotactic coordinates determination and surgical planning; third, the surgical procedure itself and its control. The most frequent applications for stereotactic methodology are: image-guided stereotactic biopsies of brain tumors, in order to obtain tissue pathological diagnosis and spatial configuration; linac-based radiosurgery of arterio-venous malformations and tumors with high energy collimated beams converging towards a simple or complex target volume; surgery for partial drug-resistant epilepsy including depth electrode implantation for stereo-electroencephalography and epileptogenic cortex resection; stereotactic image-guided resection of superficial or deep-seated tumors or vascular malformation; Rhenium 186 intracavitary irradiation of cystic tumors such as craniopharyngiomas.

Biopsy↗
PubMed1996

[The rolandic line: a simple baseline for the identification of the central region. An MRI study and functional validation].

INTRODUCTION: The identification of the central region--i.e. the central sulcus, the pre- and post-central gyri, the paracentral lobule--on MRI and angiographic images may be necessary prior to stereotactic procedures such as biopsies or resection of centrally located tumors, depth electrode recordings for presurgical evaluation of drug-resistant epilepsies, or radiosurgery of arteriovenous malformations. Stereotactic methods, such as the Talairach's proportional grid based on the bicommissural system, demonstrated the statistical position of the central sulcus according to the Ac-Pc, Vac and Vpc baselines. However, the course and the spatial position of this sulcus have remarkable individual differences that sometimes make the sulcus difficult to identify on serial sagittal MRI or lateral angiographic images. In order to facilitate this identification, the authors propose a new oblique baseline, the rolandic (R) line. MATERIAL AND METHODS: The stereotactic MRI and angiography of 22 patients were reviewed for this study. Eleven of these patients had stereotactic biopsies for a low-grade tumor located in the central region, while eleven others had multiple intracerebral electrodes implantation and depth EEG recording (SEEG: stereoelectroencephalography) in the presurgical evaluation of drug-resistant partial epilepsy, prior to epileptogenic cortex resection. The Ac-Pc, Vac, Vpc baselines and segments of the central sulcus were drawn from the mid-sagittal and lateral T1-weighted MRI images and reported on an individual graph. Surface and deep margins as well as axis of the central sulcus were also reported along with corpus callosum baselines as defined by Olivier et al.: horizontal plane, anterior and posterior callosal planes. The rolandic line was then traced from the graph:it joined the intersection point between the anterior callosal plane and an orthogonal line passing through the floor of the temporal fossa, and the intersection point between posterior callosal plane and an orthogonal line passing through the top of the hemisphere. The rolandic line was then superimposed on any sagittal MRI image or lateral stereotactic angiographic film. Finally, the spatial position of electrode contracts through which electrical stimulations elicited motor and/or sensory responses, either from central electrode implanted for motor fibers identification prior to stereotactic biopsies or from SEEG electrodes implanted for epileptogenic zone identification and cortical mapping, was reported on the individual graph. Angular and linear measurements were taken from the graph, between the rolandic line, the central sulcus axis, the Ac-Pc and callosal baselines, and the central sulcus limits (top, bottom, anterior and posterior margins). RESULTS: Graph measurements indicated that the rolandic line was significantly closer to the inferior part of the central sulcus than to its superior part (average distance between the line and the inferior point of the sulcus: 1.86 +/- 1.87 mm; average distance between the line and the superior point of the sulcus: 4.5 +/- 2.3 mm; p < 0.001-t test); similarly, the rolandic line was closer to the deep margin of the sulcus rather than to its superficial border (average distance between the line and the most anterior point of the sulcus: 11.43 +/- 3.16 mm; average distance between the line and the most posterior point of the sulcus: 7.95 +/- 4.14 mm; p < 0.01-t test). In 90% of the cases, the rolandic line followed the deep or middle part of the sulcus, with an average angle of 4.18 degrees +/- 2.53 degrees between the line and the sulcus axis. The spatial position of the electrode contacts that elicited motor/or sensory responses to stimulations correlated topographically well in all cases with the position of the motor and sensory fibers defined according to the central sulcus, baselines and reference to stereotactic atlases. (ABSTRACT TRUNCATED)

Adolescent↗
PubMed1996

[The Codman Medos programmable shunt valve. Evaluation of 53 implantations in 50 patients].

Fifty three Codman Medos programmable valves were implanted in 50 patients (28 men and 22 women) aged 5 to 77 years, from April 1992 to February 1994. They presented with a hydrocephalus 43 times, an arachnoid cyst three times and a CSF leakage four times. The aims of this study were: a) to test the reliability of this equipment, in current use as well as its eventual advantages, inconveniences and restraints, b) to determine its best indications. Follow-up ranged from 12 to 36 months (average = 22 months). Five patients were lost for follow-up. One patient died from a post-operative sepsis. Four died from their disease. Infectious complications concerned 6 patients (11%). A radio-clinical overdrainage syndrome appeared in 9 patients with slit-ventricles, 5 of them associated with sub-dural collections. All these cases were treated with shunt reprogrammings. While 43 pressure settings over 53 were satisfactory in the immediate post-operative period, it appeared that only 38% of shunts had required one only setting when the study period was over. A certain number of pressure adjustments malfunctioned: 6 times, post-operative X-ray controls showed pressures significantly different from the figures which had been selected (difference from -30 mm H2O to + 70 mm H2O); pressure readjustments were effective and accurate for five of them, but one shunt had to be changed; 15 deprogrammings were detected during long term follow-up, 9 of them after MR1. Pressure programming was readjusted only on patients presenting with clinical signs, i-e mainly for those having a pressure difference > +/-30 mm H2O. As a conclusion, the authors consider that such a shunt can be very useful in some precise indications as: NPH, multioperated hydrocephalus, arachnoid and porencephalic cysts, some spontaneous or iatrogenic CSF leakages, temporary shunts necessitating a progressive withdrawal. Because of a) the cost of this equipment, b) the specific restraints (X-rays controls, programmer), and c) the specific incidents (spontaneous and/or post-MR1 deprogramming), it seems difficult to generalize indications to all cases of hydrocephalus. On the other hand, these shunts have the great advantage of simplifying the treatment of overdrainage by avoiding, in all cases, a reoperation for changing the shunt and/or removing a subdural hematoma. Consequent economies due to a significant diminution of the duration of hospitalisation, could justify an enlargement of indications.

Adolescent↗
PubMed1995

Inter-ictal brain SPET in frontal epilepsy: correlations with stereo-electroencephalography.

Single photon emission tomography (SPET) imaging holds promise for localization of the site of extratemporal seizures, but limited data currently exist; in particular, correlations with stereo-electroencephalography (S-EEG) have not been made. Ten patients aged 14-44 years (mean 25 years) with a proven frontal or central epilepsy by S-EEG and post-surgical follow-up were studied retrospectively: 7 patients had frontal cortectomy and one patient had a callosotomy for bifrontal epilepsy. All patients underwent clinical, inter-ictal and ictal video-EEG, computed tomography scan and/or magnetic resonance imaging, SPET and S-EEG examinations. SPET was performed inter-ictally, while on usual epileptic medications, using 99Tcm-HMPAO (n = 4) or 123I-IMP (n = 6) as the perfusion tracer. The SPET images were evaluated independently by two observers, blind to any data other than the diagnosis of frontral or central epilepsy. Localization of inter-ictal SPET hypoperfusion was compared with the epileptogenic (EZ), irritative (IZ) and lesional (LZ) zones, as defined by S-EEG. Six patients showed structural frontal abnormalities. One patient had normal SPET and one had a contralateral hypoperfusion. Therefore, concordance of sides was found in 8 of 10 patients (including one with bilateral SPET and S-EEG abnormalities). The hypoperfusion was equal to or larger than the EZ + IZ + LZ in 6 patients (5 had a frontal lesion). SPET hypoperfusion was smaller than the EZ in one patient, and different from the EZ, IZ and LZ in two patients. Although this was a retrospective study, it provides qualitative data regarding the significance of inter-ictal SPET abnormalities in frontal or central epilepsy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Stereotactic approach to intracranial lesions.

The diagnostic and therapeutic approach to intracranial lesions must be different considering the different possibilities offered by the various methods. The diagnostic reliability and safety of stereotactic biopsy are often indispensable in order to optimize the subsequent therapy. The results obtained in selected pathologies allow us to propose the stereotactic approach to treat: -various kind of cysts by aspiration and/or Beta endocavitary radiation therapy; -blood or abscessual collections that can be aspirated in a similar way; -arterio venous malformations or tumours by radiosurgery; -tumours by brachicurietherapy or by computer assisted stereotactic surgery. We present some cases treated at the C.H.S.A. of Paris and at the C.H.R.U. of Grenoble utilizing Talairach methodology.

Adolescent↗
PubMed1992

[Combined CO2 and Nd-YAG laser in neurosurgical practice. A 1st experience apropos of 40 intracranial procedures].

The authors present their experience concerning the use of Combolaser (Lasermatic, Finland), in neurosurgery. This laser-unit combines two wavelengths (CO2 and 1.06 Nd-YAG) which are emitted simultaneously and coaxially. During the last 12 months, 40 patients harbouring an intracranial tumor were operated upon with such a combolaser unit: 8 infra-tentorial, 32 supra-tentorial, 17 were meningiomas. The mean output power used during the procedures was 3-5 w for both CO2 and Nd-YAG beams. The authors discuss the advantages and inconveniences of such a laser; and they compare it with the other laser-units they have been using for the last 10 years: CO2-Laser, 1.06 Nd-YAG and 1.32 Nd-YAG laser. The main inconvenience of this unit is linked to the utilization of the articulated arm which conducts the CO2 laser beam. This drawback should be avoided or limited by the use of a fiber microguide, which will conduct both CO2 and Nd-YAG beams simultaneously. The principal contribution of a combined-laser unit is the quality of the haemostasis associated to a very good vaporization and cutting effect. When both wavelengths are synchronized, the combined laser beams penetrate into the nervous parenchyma more deeply than the only CO2 laser beam would with the same parameters. The vaporization effect is identical to that obtained with the isolated CO2 laser; the quality of haemostasis is limited to the effects of the Nd-YAG laser. Another advantage must be emphasized: the possibility of utilizing separately the CO2 laser and the 1.06 Nd-YAG.

Adolescent↗
PubMedDate not supplied

Long term results of stereotactic endocavitary beta irradiation of craniopharyngioma cysts.

This study concerns 33 pts (age: 3-69 yrs; m: 22) with cystic craniopharyngiomas (36 cysts) treated with stereotactic beta endocavitary irradiation (TRT). Nine patients died (3 days to 36 months after TRT) and one was lost. In 23 the follow-up varied from 12 to 126 months (m: 45 months). The disappearance of 13 cysts was appreciated 5 to 24 months after TRT: no recurrence was observed after 22-126 months (m: 61). A greater than 70% reduction of the cyst volume occurred 3-36 months after TRT and persisted at 12-71 months (m: 35 m). In one patient, the cyst volume increased. Visual acuity improved in more than 50% of survivors, while endocrine disturbances did not change and memory troubles disappeared.

Adolescent↗