Biomedical subjects

G Lot

Publications and source records attributed to G Lot.

At least 55 records · Page 3Linked to original sources

PubMed1994

[Seven cases of subependymoma. Anatomoclinical study and review of the literature].

Subependymomas are uncommon, benign, slowly growing lesions usually located in the fourth ventricle. Their morphology is characteristic, but their histogenesis remains controversial. Seven cases observed in our laboratory over a period of 7 years are reported. Most tumors were located axially in the brain stem, and symptoms were more variable than usually reported. The histological appearance was fairly uniform. Immunohistochemistry showed that the fibrillary component was composed of glial fibers. Ependymary differentiation is inconstant on electron microscopy. The pathogenesis of the lesion (tumor, hamartoma or reactive proliferation) is debated in the literature as is the histogenesis.

Adult↗

PubMed1993

[Intracranial cavernoma. 30 cases].

During the last few years, as a result of improved neurodiagnostic procedure there has been an increase in the number of intracranial cavernous angioma. We present 30 cases totalling 32 cavernous angiomas. Twenty-one received a successful surgical treatment. Twenty-four angiomas were supratentorial (75 percent) and 8 subtentorial (25 percent). Cavernous angiomas are congenital vascular malformations, usually of small size, with multiple vascular cavities surrounded by fibrous walls. They are often found in young adults (mean age 35 years in our series), most frequently located in the supratentorial white matter. The presenting symptoms were epilepsy, haemorrhage and an expanding mass syndrome. In this series, 16 patients had epilepsy (53 percent), 7 had haemorrhage (23.5 percent) and 7 had a mass syndrome (23.5 percent). The diagnosis of this lesion, usually obtained with angiography, has been dramatically improved by CT scan and, particularly, MRI. The natural history of cavernous angiomas is still poorly understood: the major complication is haemorrhage. Total surgical excision is the treatment of choice: it avoids a possible haemorrhage and is effective in relieving epileptic seizures. The indication for surgery depends on the clinical symptom and the location of the lesion. The post-operative morbidity in our 21 operated cases was fairly low due to minor sequelae. In only 2 of the 16 patients who had epilepsy the clinical seizures persisted after surgery, but they were less frequent. The literature is reviewed.

Adolescent↗

PubMed1993

Pyogenic parenchymatous and nidus infection after embolization of an arteriovenous malformation. An unusual complication. Case report.

Infectious complications of cerebral angiography and of therapeutic angiographic procedures are very seldom reported. The case of an infected embolized arteriovenous malformation (AVM) by staphylococcus aureus is reported. Abscess formation became manifest seven months after the endovascular procedures. Antibiotherapy was initially started after puncturing the abscess, but finally the cure of the lesion could only be obtained by radical excision of the infected and embolized AVM, as if the persisting embolization material was promoting the infection. The modalities of infection after cerebral endovascular procedures are discussed.

Adult↗

PubMed1993

Phase contrast magnetic resonance of the spinal cord preliminary results in spinal cord arterio-venous malformations.

In spite of the recent advances in neuroradiology including the CT scan and the spin-echo-magnetic resonance (MR), accurate diagnosis of arteriovenous malformations (AVMs) involving the spinal cord is still based on selective angiography. This last procedure is invasive and needs to be repeated during the follow up. Phase contrast angio MR was performed with a 0.5 Tesla unit on 12 patients with an AVM involving the spinal cord (7 intramedullary AVMs, 4 perimedullary fistulas, and 1 dural fistula with perimedullary venous drainage); 4 of these were investigated before and after treatment. Angio MR showed abnormal vascular patterns within the spinal canal in all cases, without distinguishing between arteries and veins; the nidus of the intramedullary AVMs was displayed in all cases. Angio MR provided images of the whole AVMs comparable to the angiographic pictures, in contrast to the spin-echo MR, which provided only discontinued images of the vessels. The efficient range of velocity providing images varied, according to the type of the malformation (slow for dural fistulas, rapid for intra-medullary AVMs). In the 4 patients investigated after treatment, comparison of the images obtained before and after treatment permitted assessment of the degree of occlusion of the malformation. Finally, angio MR as a complement of spin-echo MR can now be used as a reliable tool for detection of spinal cord AVMs, assessing the indication for angiography, and, furthermore, it can probably replace most of the post-operative control angiographies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Oblique transcorporeal approach to anteriorly located lesions in the cervical spinal canal.

The technique of obliquely drilling out the postero-lateral part of the cervical vertebral bodies is described. It uses the antero-lateral (retro carotico-jugular) approach to control and displace the vertebral artery postero-laterally and to expose the lateral aspect of the vertebral bodies. It provides, through a wide field and with minimal retraction of the carotid artery and the internal jugular vein, an extensive view of the anterior aspect of the spinal cord. It has already been used to treat 15 anterior lesions compressing the spinal cord including neurinomas and osteophytes.

Bone Transplantation↗

PubMed1993

Intradural perimedullary arteriovenous fistulae: results of surgical and endovascular treatment in a series of 35 cases.

A series of 35 patients treated for an intradural perimedullary arteriovenous fistula (AVF) between 1970 and 1990 is reported. Angiography was performed on all of the patients, leading to the diagnosis. The patients were classified into Type I (4 patients), Type II (9 patients), and Type III (22 patients). One Type I patient was not treated, two others underwent surgery, and the last one was embolized. All of the Type II AVFs were treated, two by embolization, four by direct surgery, and three by surgery after incomplete embolization. All of the Type III AVFs were treated by endovascular detachable silicone balloon. Complete occlusion of the AVF was achieved in all treated cases of Types I and II AVF and in 15 cases of Type III AVF; for the 6 other cases of Type III AVF, incomplete occlusion was achieved. In the Types I and II AVFs, partial improvement was clinically observed in only half of the patients; the others remained unchanged. The 15 patients whose Type III AVF was completely embolized recovered completely, and four patients with Type III AVF who were incompletely embolized remained unchanged; 2 other patients with Type III AVF worsened after incomplete occlusion, and 1 additional patient died a few hours after an attempt of endovascular occlusion of a cervical Type III AVF. The place of the perimedullary AVFs among the other vascular malformations involving the spinal cord is discussed according to this classification into three types. Their specific diagnostic and therapeutic difficulties are discussed, resulting in a simplified classification including two types of perimedullary AVF.

Adolescent↗

PubMed1993

Intraforaminal neurinoma in the lumbosacral region.

A series of 12 patients with intraforaminal neurinomas in the lumbosacral space was reviewed. Our classification according to tumor extension relative to the affected root into intradural intra-arachnoid, intraforaminal extra-arachnoid, and extraforaminal types was useful in determining the best surgical approach to achieve root preservation and minimal postoperative deficits. Where sacrifice of roots was unavoidable, surprisingly few neurological deficits occurred.

Adult↗

PubMed1993

Abnormal cerebral vasodilation in aneurysmal subarachnoid hemorrhage: use of serial 133Xe cerebral blood flow measurement plus acetazolamide to assess cerebral vasospasm.

A patient with cerebral vasospasm following subarachnoid hemorrhage (SAH) was investigated by serial measurement of cerebral blood flow (CBF) using the xenon-133 emission tomography method. The CBF was measured before and after acetazolamide injection. On Day 2 after SAH, there was early local hyperperfusion in the middle cerebral artery (MCA) territory, ipsilateral to the left posterior communicating artery aneurysm. The regional CBF of this arterial territory decreased slightly after acetazolamide injection, probably because of vasoplegia and the "steal" phenomenon, and thus surgery was delayed. A right hemiplegia with aphasia and disturbed consciousness occurred 4 days later (on Day 6 after SAH) due to arterial vasospasm, despite treatment with a calcium-channel blocker. The initial hyperemia of the left MCA territory was followed by ischemia. The vasodilation induced by acetazolamide administration was significantly subnormal until Day 13, at which time CBF and vasoreactivity amplitude returned to normal and the patient's clinical condition improved. Surgery on Day 14 and outcome were without complication. It is concluded that serial CBF measurements plus acetazolamide injection are useful for monitoring the development of cerebral vasospasm to determine the most appropriate time for aneurysm surgery.

Acetazolamide↗

PubMed1993

[French language Society of Neurosurgery. 44th Annual Congress. Brussels, 8-12 June 1993. Tumors of the foramen magnum].

Since what seems to be the first reported case of foramen magnum (F.M.) tumor by Hallopeau in 1874, literature on tumoral pathology of this region is rather scarce; beside reports of single cases or short series, there are very few large series and most of them are not recent (Meyer et coll., Yasuoka et coll., Guidetti and Spallone). The present report includes 230 cases of extramedullary tumors collected from 21 french departments over the last ten years (series of the French Speaking Society of Neurosurgery = S.N.C.L.F. series). Delimitation of what is called the F.M. region is rarely given in the literature. In this report, the inferior limit is put at the C2 level and the superior one at the ponto-medullary junction and the lower third of the clivus. To belong to the F.M. region, tumor must have its main part or its insertion within these limits even if it extends beyond them. On the contrary, if the gross development is out of these limits but with some extension into the F.M. region, the case is rejected. A chapter of this report deals with the anatomy of the F.M. with emphasis on the points useful for the management of the tumors. Some details are given on the dimensions of the different parts of the F.M. as given by anatomical studies and also by measurements on C.T. scanner and M.R.I. including during flexion and extension of the head. The S.N.C.L.F. series is then analyzed as a whole. It includes 106 meningiomas (M), 49 neurinomas (N), 28 chordomas (Ch), 32 osseous tumors (T.Os) (19 primary and 13 metastasis) and 15 cases considered as uncommon tumors. (T. Part.) (4 melanomas, 3 hemangioblastomas, 3 dermoid or epidermoid cysts, 2 ependymomas, 1 cavernoma, 1 angiomyolipoma and 1 cholesterin cyst). Mean age is 47 years, with a sex ratio F/M of 1.5/1. Duration of symptoms before diagnosis is of 27 months. Topography is classified into 3 groups anterior (70 cases), lateral (142 cases) and posterior (24 cases). A particular definition is given to these localizations, essentially referring to surgical difficulties and specially for meningiomas. The localization of a tumor is defined by the point of attachment to any structure (dura, spinal root, spinal cord); anterior tumors are attached to the F.M. on both sides of the midline; lateral tumors between the midline and the dentate ligament and posterior ones behind the dentate ligament. According to this way of classification, N are always lateral even if they present anterior or posterior extensions.(ABSTRACT TRUNCATED AT 400 WORDS)

Brain Neoplasms↗

PubMed1993

[Cervical spondylosis. Resection by oblique transcorporeal approach].

Spondylosis at the cervical level inducing anterior spinal cord compression is generally treated by anterior transcorporeal resection of the osteophytic spurs. We report on 12 cases over 2 years in which a new technique has been applied; it uses the lateral approach exposing and retracting laterally the vertebral artery; then, the vertebral bodies are drilled out obliquely from the anterolateral corner to the posterolateral one on the opposite side. The vertebral bodies were drilled using this technique on 1 level in 2 cases, on 2 levels in 4, on 3 levels in 5 and on 4 levels in 1; the C4-C5, C5-C6 and C6-C7 levels were the most frequent sites involved in 9, 8 and 6 cases respectively. No graft or arthrodesis was used since the stability of the spine was never compromised. Improvement of the neurological symptoms was observed in all the cases with the best results achieved on the motor deficit and sphincter disturbances. Every case was controlled by dynamic standard radiographies (flexion-extension), CT scan and MRI. The results were good in all cases in terms of osteophytes resection, spinal cord decompression and spinal stability. This technique of oblique resection of the cervical bodies seems quite efficient to alleviate spondylotic compression of the spinal cord; moreover, it appears simpler and safer than the anterior route since the operative field is much wider with all the vital structures protected and retracted medially and bone grafting is never necessary.

Adult↗

PubMed1993

[Report of a case of rhabdomyosarcoma of the central nervous system. Histologic, immunohistochemical and ultrastructural study].

A patient, aged 26, had a large parietal tumor, clinically revealed by intracranial hypertension and left sized paresthesia. Removal of tumor was followed by a rapid recurrence. Rhabdomyosarcoma was diagnosed on the second surgical specimen. These tumors are rare in the central nervous system. They occur mostly, though not exclusively, in young adults. Their prognosis is poor and their histogenesis is still unclear.

Adult↗

PubMed1992

Arteriovenous malformations of the posterior fossa.

AVMs of the posterior fossa are reviewed on the basis of personal experience of 47 cases including 2 venous angiomas, 7 cavernous angiomas, 5 arteriovenous fistulas and 33 true arteriovenous malformations and of the few series reported in the literature. MRI is now an indispensable tool to define the exact localization of any malformation. Combined with angiography, it permits one to choose the most adequate therapeutic strategy and the best surgical approach. Radical cure is to be contemplated in most cases considering the often dramatic consequences of bleeding at the infratentorial level. Deep AVMs and moreover cavernous angiomas, even those located in highly functional structures such as the brain stem, can now be discussed for treatment. Encouraging results have already been obtained using, alone or in association, the recently advanced modalities of treatment: interventional neuroradiology, radiosurgery, and microsurgery.

Brain Neoplasms↗

PubMed1992

[Cerebral blood flow in the determination of vasospasm and surgical decision].

The interest of C.B.F. studies performed on patients with subarachnoid haemorrhage is discussed on the basis of the literature and of our experience of 142 cases. C.B.F. results in basic condition are influenced by many factors which make its use very limited and especially during the first days after haemorrhage (J0-J3). However, the analysis of the evolution of C.B.F. values in the same patient and moreover the C.B.F. reactivity to acetazolamide are good indicators of the occurrence of a vasospasm; progressive drop of the C.B.F. or poor reactivity are generally observed before clinical signs of vasospasm. Our policy is therefore to decide the date of surgery according to C.B.F. values but only for patients planned for delayed surgery (after the 3rd day).

Acetazolamide↗

PubMed1992

[Cisternal cysticercosis of the cerebellopontine angle. A surgically-treated case and review of the literature].

Most neurocysticercosis (N.C.C.) cases reported occur in undeveloped countries where contaminated food by Taenia solium gives rise to human infection. People of developed countries are exposed by migrations and travels. We report a case of a 36 years old french woman living at La Reunion. Her symptomatology consisted of left unilateral hypoacusis progressing over a two years period accompagnied by intermittent headaches. CT scan showed a hypodense mass with a ring enhancement in the left cerebello pontine angle (C.P.A.). M.R.I. showed multicystic arrangement of vesicles in a racemous fashion that spread out to peduncular and carotid cisterns. Parenchymatous or ventricular involvement was not observed. A lateral suboccipital craniectomy was carried up in the sitting position. After division of a thickened arachnoid in the C.P.A., the vesicles were dissected an pulled out easily because the membranes had not any adhesions. Progressive improvement of hearing was observed in the next week. Primary cisternal involvement of N.C.C. is rare and, in literature, there is not any other reported case in the C.P.A. Different mechanisms of invasion to the C.N.S. are discussed.

Adult↗

PubMed1991

Anterior skull base tumour. The choice between cranial and facial approaches, single and combined procedure. From a series of 78 cases.

In order to define the most adequate surgical procedure to apply on anterior skull base lesions, we reviewed 78 cases of either benign (43 cases) or malignant (35 cases) tumours; they were treated either by a single surgical approach including transfacial approach (TF) in 9 cases, transbasal approach (TB) in 15 cases and fronto-orbital ridge deposition (FORD) in 16 cases or by a combined procedure: TB + TF (28 cases), TB + FORD (10 cases). In 7 cases, a pterional approach was associated to one of these combined procedures. A classification is proposed, based on the tumour extension along the anteroposterior axis: I) anterior to the crista galli; II) anterior to the anterior clinoïd process; III) posterior to the anterior clinoïd process; and along the vertical axis A: below the bone level; B: below the dura level; C: at and above the dura level. This classification appears very useful to choose among the surgical procedures which one is the more appropriate. In type A tumour (N = 8), TF is sufficient while in type B (N = 38) and C (N = 32) a cranial route is always necessary; among the latter, a combined procedure is frequently asked for posterior tumours type II (N = 29) and III (N = 24). However, others parameters such as tumour consistency, vascularization and need for en-bloc removal are also relevant in this choice.

Adolescent↗

PubMed1991

[Value of the measurement of cerebral blood flow before and after diamox injection in predicting clinical vasospasm and final outcome in aneurysmal subarachnoid hemorrhage].

The timing for surgery on ruptured intracranial aneurysms remains a difficult question and the choice of the day of operation depends greatly from the occurrence of a vasospasm. On a previous paper, the value of the cerebral blood flow (CBF) measurement by intravenous injection of Xenon 133 was demonstrated to be efficient for the prediction of vasospasm only when done between day 4 and day 8 after bleeding. Moreover the efficiency of the measurement was much greater if the evolution of the CBF values between D0 and D8 was considered, but this method was incompatible with early surgery. It suggested the interest of a dynamic study of the CBF by the same method. On a series of 43 patients, the comparison between basal CBF values and reactivity of CBF values to intravenous injection of 1 gram of acetazolamide for the prediction of clinical vasospasm is presented. The series comprises 32 early admitted patients (74%) and 31 operated patients (16 of them between D0 and D3 after bleeding, 15 others after D4). The efficiency of the CBF reactivity study for the prediction of the clinical vasospasm appears much greater than that of the basal CBF value, even during the first three days after bleeding, but not for the prediction of the final clinical outcome. The method is immediate and compatible with early surgery. What precisely is evaluated by this method on the physiopathology of the vasospasm remains disputable, but the operability of the patients seems to be explored.

Acetazolamide↗

PubMed1991

[Intraforaminal lumbosacral neurinoma].

Twelve cases of intra-foraminal localization of lumbosacral neurinoma are reported including 9 schwannomas, 2 neurifibromas and 1 melanotic schannoma. According to their extension, they are classified in type II strictly intra-foraminal and extra-arachnoïdal: N = 6, type I-II, extending into the subarachnoïdal space; N = 5, type II-III, extending out of the spine. There were 7 men and 5 women with mean age of 49.5 years and a 5.2 years delay before diagnosis. The most common, though not permanent, symptom was radiculalgia; a generally weak sensorimotor deficit was noticed in 4 cases and hypoesthesia in two cases. Diagnosis was sometimes doubtful using myelography for the oldest cases, but is now made easily with CT scan and M.R.I. Microsurgery allows to dissect out the tumor inside the perineural sheath and to preserve the nervous root in most cases even in extra-arachnoïdal forms (N = 8). However, in cases of neurofibromas and of large tumors, the root had to be divided (N = 4) with rather surprisingly no new post-operative deficits. Intra-foraminal localization of lombo-sacral neurinomas is rare but now easily identified; it should be cured surgically with the goal, often reached, of maximum preservation of the nervous root.

Adult↗

PubMed1991

[Evaluation of cerebral blood flow in severe brain injuries by SVO2 measurement in the internal jugular vein].

The purpose of the present study was to assess the value of jugular oxyhemoglobin saturation percent (SvO2) in predicting cerebral blood flow (CBF). SvO2 and CBF were measured in 25 adults with acute brain trauma (Glasgow Coma Scale < 8). From the data a classification of CBS and SvO2 was developed: in the first group of patients the presence of cerebral ischemia could be identified in the presence of low CBF (< 40 ml/min/100g) and a low SvO2. In the second group he CBF is closely coupled to and regulated by the cerebral metabolic rate of oxygen (CMRO2) and values of SvO2 are intermediate. In the third group hyperaemia was defined as both an increase of SvO2 and CBF (> 60ml/min/100g) and a decrease of CMRO2. The SvO2 was measured in 18 of these 25 patients following 1) intravenous infusion of mannitol (1 g.kg-1) and hyperventilation (PCO2 = 3.4 kPa). The data suggest that there is no correlation between SvO2 and CBF, but a reliable estimates of CBF may be made from SvO2 measurement after mannitol and hyperventilation.

Blood Flow Velocity↗