[Early epidural hematoma after CSF shunt for obstructive hydrocephalus]. / Hématome extradural précoce après dérivation interne du liquide céphalorachidien pour hydrocéphalie non communicante.

We present the first case of early epidural hematoma after CSF shunt probably caused by defective material. A 26-year-old man was treated for obstructive hydrocephalus associated with a tonsillar herniation, revealed by headaches and papillary edema. Ventriculoperitoneal shunt was preferred to endoscopic ventriculostomy. Three hours after the operation, the patient fell into a coma, developing a voluminous bifrontal epidural hematoma that was evacuated immediately. The patient completely recovered neurologically. One month later, to treat persistent hydrocephalus, endoscopic ventriculostomy was performed without incident. Then the shunt was removed and an opening threshold close to zero was discovered. Distant MRI showed a reduction in ventricular size, normalization of the tonsils' position and a tumor of the tectal plate. To our knowledge, this is the only case of early epidural hematoma after ventriculoperitoneal shunt. We discuss the choice of treatments for obstructive hydrocephalus and its risks and complications.

Contribution of intraoperative electrical stimulations in surgery of low grade gliomas: a comparative study between two series without (1985-96) and with (1996-2003) functional mapping in the same institution.

OBJECTIVES: Despite the growing use of intraoperative functional mapping in supratentorial low grade glioma (LGG) surgery, few studies have compared series of patients operated on without and with direct electrical stimulation (DES) by the same team. The present study compared the rate of LGG surgery performed in eloquent areas, the rate of postoperative sequelae, and the quality of resection during two consecutive periods in the same department-the first without and the second with the use of intraoperative electrophysiology. METHODS: Between 1985 and 1996, 100 patients harbouring a supratentorial LGG underwent surgery with no functional mapping (S1). Between 1996 and 2003, 122 patients were operated on in the same department for a supratentorial LGG using intraoperative cortico-subcortical DES (S2). RESULTS: Comparison between the two series showed that 35% of LGGs were operated on in eloquent areas in S1 versus 62% in S2 (p<0.0001), with 17% severe permanent deficits in S1 versus 6.5% in S2 (p<0.019). On postoperative MRI, 37% of resections were subtotal and 6% total in S1 versus 50.8% and 25.4%, respectively, in S2 (p<0.001). In both groups, survival was significantly related to the quality of resection. CONCLUSIONS: The results of the present study allow, for the first time, quantification of the contribution of intraoperative DES in LGG resection. Indeed, the use of this method leads to the extension of indications of LGG surgery within eloquent areas; to a decrease in the risk of sequelae; and to improvement of the quality of tumour resection, with an impact on survival.

Functional recovery after surgical resection of low grade gliomas in eloquent brain: hypothesis of brain compensation.

OBJECTIVES: To describe functional recovery after surgical resection of low grade gliomas (LGG) in eloquent brain areas, and discuss the mechanisms of compensation. METHODS: Seventy-seven right-handed patients without deficit were operated on for a LGG invading primary and/or secondary sensorimotor and/or language areas, as shown anatomically by pre-operative MRI and intraoperatively by electrical brain stimulation and cortico-subcortical mapping. RESULTS: Tumours involved 31 supplementary motor areas, 28 insulas, 8 primary somatosensory areas, 4 primary motor areas, 4 Broca's areas, and 2 left temporal language areas. All patients had immediate post-operative deficits. Recovery occurred within 3 months in all except four cases (definitive morbidity: 5%). Ninety-two percent of the lesions were either totally or extensively resected on post-operative MRI. CONCLUSIONS: These findings suggest that spatio-temporal functional re-organisation is possible in peritumoural brain, and that the process is dynamic. The recruitment of compensatory areas with long term perilesional functional reshaping would explain why: before surgery, there is no clinical deficit despite the tumour growth in eloquent regions; immediately after surgery, the occurrence of a deficit, which could be due to the resection of invaded areas participating (but not essential) to the function; and why three months after surgery, almost complete recovery had occurred. This brain plasticity, which decreases the long term risk of surgical morbidity, may be used to extend the limits of surgery in eloquent areas.

A new device for electrical stimulation mapping of the brainstem and spinal cord.

With the goal to minimize the risk of sequelae in brainstem and spinal cord surgery, methods of intraoperative mapping using direct electrical stimulations were developed in the last decade. However, the current was delivered with a monopolar stimulator with risk of a spreading, or using a bipolar probe or silicone strip with 5 mm of precision. To improve the accuracy and easiness of the mapping, the authors describe in this work a new device with the following characteristics: bipolar probe without current diffusion; reduction of the space tips to 2 mm; building of a bent handle, improving the field of view and ergonomics under the microscope. This device has been used successfully in 6 consecutive patients, 4 harboring a brainstem lesion and 2 with a spinal cord tumor. This new device allows the surgeon to perform repetitive intraoperative brainstem and spinal cord electrical mapping under the microscope in a very simple, quick and accurate way all along the resection. Improvement of such a mapping first minimizes the risk of sequelae, second optimizes the quality of resection, and third may also give a prognostic value concerning the changes of postsurgical recovery in case of a preoperative deficit.

Intracranial extra-axial cavernous (HEM) angiomas: tumors or vascular malformations?

INTRODUCTION: Extra-axial cavernous hemangiomas or angiomas [(hem)angiomas] are relatively rare lesions. They usually arise in relation to the dura mater intracranially or at the spinal level. Most of these lesions have been described in the middle cranial fossa at level of the cavernous sinus. Controversy still exists regarding the exact nature of these extra-axial cavernous angiomas: vascular tumor versus vascular malformation similar to intra-axial cavernomas. It has been suggested that they could represent an adult form of the hemangioma of infancy. Extra-axial cavernous (hem)angiomas often mimic meningiomas and their clinical behavior and imaging appearance are quite different than those of intra-axial cavernous angiomas. SUBJECTS AND METHODS: Five patients ranging in age from 24 to 63 years with a histologically proven dural cavernous angioma were retrospectively included. The lesions were located at level of the cavernous sinus (4 cases) and falx. CT and MR scans were performed in all cases and angiography in three patients. Four patients underwent surgery and a biopsy was performed in one case. One lesion was embolized before biopsy. Histology was available in all patients. RESULTS: In the operated patients, the lesion was totally resected in 2 cases and partially in the other 2. No postsurgical complication was noted. Histology revealed a vascular malformation composed of large vascular channels lined by flat endothelium and separated by fibroconnective tissue stroma. The pathological diagnosis was cavernous angioma. CONCLUSION: On the basis of the analysis of the literature and of our cases, intra-cranial extra-cerebral so-called cavernous (hem)angiomas present findings suggesting that they are vascular malformative lesions, analogous to the intra-axial cavernous angioma. A relationship with the hemangiomas of infancy seems unlikely. Correct terms for extra-cerebral cavernous (hem)angiomas are cavernoma, cavernous angioma, or venous vascular malformation of cavernous type . The term hemangioma should be avoided and reserved for the common vascular tumor of infancy.

Medically intractable epilepsy from insular low-grade gliomas: improvement after an extended lesionectomy.

OBJECTIVE: With the aim to better evaluate the role of the insula in seizures and the therapeutic implications, we analyzed the rate of insular low-grade gliomas (LGG) presenting with medically refractory epilepsy, detailed their ictal symptoms, and described the epileptological results following their surgical resection. METHODS: Eleven patients (8 men, 3 women, mean age: 35 years) harboring an insular LGG generating intractable seizures, underwent tumor removal and perilesional opercular cortex resection (lesionectomy "plus") using intraoperative functional electrical mapping, combined with ultrasonography and/or neuronavigation. RESULTS: Despite the occurrence of five postoperative deficits, the patients recovered in all cases. The epileptological results showed improvement in all cases: 9 Engel's Class I (82%), 1 Class II and 1 Class III. Ten lesionectomies were total [3] or subtotal [7], while one resection was partial (the patient in Engel's III). CONCLUSION: The high rate of pharmacologically intractable seizures associated with insular LGG, and the favorable epilepsy outcome following surgical resection of these tumors seemingly indicate that the insular cortex itself may induce chronic seizures when injured. These results suggest, taking account of the technical surgical progress allowing now to minimize the morbidity after surgery in this region, that there is another indication than the sole oncological reason for surgery in patients with diffuse insular glioma -- even if total tumor removal is not systematically possible.

[Surgery of intracranial epidermoid cysts. Report of 44 patients and review of the literature]. / Prise en charge chirurgicale des kystes épidermoïdes intracrâniens. A propos de 44 patients et revue de la littérature.

Forty-four patients (22 males and 22 females) were admitted to our institution for an intracranial epidermoid cyst between 1980 and 2000. Their mean age was 39.9 years. The duration of the disease at admission varied between a few days and 30 years. CT-scan was performed in all cases, MRI in 33 cases with a diffusion sequence in 3. Most of the 26 patients with posterior fossa lesions were treated surgically in the sitting position, with resection of the tonsils in four cases in order to minimize cerebellar retraction. The other supratentorial tumors were operated using a fronto-temporo-pterional approach in 13 cases (with temporo-polar lobectomy in 6 cases), or a parietal transparenchymal approach in the parieto-occipital lesions (2 cases). The resection was total or subtotal (residual capsule) in 79.5% of cases. Post-operative morbidity was 13.6% and mortality 8.9%. The median follow-up was 8 years, with a recurrence rate of 4.5%. Epidermoid cysts are benign, slowly but ineluctably growing tumors which require surgical treatment. Their diagnosis has become easier, especially with the development of MRI diffusion sequences. Morbidity and mortality (morbi-mortality) reported in the literature as well as found in our series seems to be unrelated to classical aseptic meningitis (22.7% in our series) or hydrocephalus (2 cases in our series). For many authors, it may be the consequence of systematic resection of the tumor capsule. This does not seem to be the case in our series in which only 25% of the patients underwent a complete resection. Prolonged cerebral retraction could be one of the responsible factors. One of the technical proposals could be to perform a transparenchymal approach in selected patients.

The insular lobe: physiopathological and surgical considerations.

OBJECTIVE: Surgery of the insula represents a technical challenge, because of the proximity of the internal capsule to the lenticulostriate arteries and the lack of certainty concerning its functionality. Using intraoperative direct cerebral stimulation, combined with neuronavigation, the authors operated on 12 insular gliomas. On the basis of this experience, the physiopathological and surgical implications are discussed. METHODS: A low-grade insular glioma, revealed by seizures, was diagnosed in 12 right-handed patients with a normal neurological status. Preoperative magnetic resonance imaging showed that, according to Yasargil's classification system, three patients harbored Type 3 lesions and nine patients had Type 5 lesions (10 tumors on the right side and 2 on the left dominant side). All patients underwent surgery using direct cerebral stimulation, under general anesthesia in nine patients (motor mapping) and under local anesthesia in three patients (sensorimotor and language mapping). Ultrasonography and/or neuronavigation was used in all cases. Preoperative angio-computed tomographic scanning showed the lenticulostriate arteries in two patients. RESULTS: The internal capsule was systematically detected, and the language areas were identified within the left insula in the awake patients. The lenticulostriate arteries were seen in two patients. Seven patients presented an immediate postoperative deficit; six of them recovered completely within 3 months. Four resections were total, six were subtotal, and two were partial (left insula). CONCLUSION: The use of intraoperative direct cerebral stimulation and neuronavigation allows surgery of the insula with minimization of the risk of sequelae, but its use is still limited with regard to the dominant hemisphere, owing to the essential role of this structure in language.

Intradural spinal lipoma of the conus medullaris without spinal dysraphism.

A 42-year-old man suffering from progressive left radicular sensory motor loss (L4 level) underwent neurosurgical repair. Neuroimaging (RMI) had led to the diagnosis of schwannoma of the filum terminale with lipomatous component. Histological examination visualized a true mature lipoma associated with numerous bundles of more or less dystrophic nerve fibers. This histological benign tumor raised the problem of the genesis of intradural lipomas of spinal cord.

Correspondence between functional magnetic resonance imaging somatotopy and individual brain anatomy of the central region: comparison with intraoperative stimulation in patients with brain tumors.

OBJECT: The goal of this study was to determine the somatotopical structure-function relationships of the primary motor cortex in individual patients by using functional magnetic resonance (fMR) imaging. This was done to assess whether there is a displacement of functional areas compared with anatomical landmarks in patients harboring brain tumors close to the central region, and to validate these findings with intraoperative cortical stimulation. METHODS: One hundred twenty hemispheres in 60 patients were studied by obtaining blood oxygen level-dependent fMR images in patients while they performed movements of the foot, hand, and face on both sides. There was a good correspondence between anatomical landmarks in the deep portion of the central sulcus on axial slices and the somatotopical organization of primary motor areas. Pixels activated during hand movements were centered on a small characteristic digitation; those activated during movements in the face and foot areas were located in the lower portion of the central sulcus (lateral to the hand area) and around the termination of the central sulcus, respectively. In diseased hemispheres, signal-intensity changes were still observed in the projection of the expected anatomical area. The fMR imaging data mapped intraoperative electrical stimulation in 92% of positive sites. CONCLUSIONS: There was a high correspondence between the somatotopical anatomy and function in the central sulcus, which was similar in normal and diseased hemispheres. The fMR imaging and electrical stimulation data were highly concordant. These findings may enable the neurosurgeon to locate primary motor areas more easily during surgery.

Parenchymal pineal tumors: a clinicopathological study of 76 cases.

PURPOSE: The aim of this study was to identify factors that could lead to optimization of the management of pineal parenchymal tumors (PPT) which remains equivocal and controversial. METHODS AND MATERIALS: In order to determine factors that influence PPT prognosis, a series of 76 consecutive patients from 12 European centers with histologically proven tumors was retrospectively reviewed. The clinical records and material for histologic review were available in all cases. Follow-up was achieved in 90% of cases. RESULTS: According to WHO classification, there were 19 pineocytomas, 28 intermediate and mixed PPT, and 29 pineoblastomas. According to a four-grade institutional classification, there were 11 Grade 1, 27 Grade 2, 20 Grade 3, and 18 Grade 4. Surgical resection was attempted in 44 patients, whereas 30 had biopsy only. In one case, diagnosis was made at autopsy and in another on spinal deposits. Forty-four patients were irradiated following surgery, 15 patients received chemotherapy. Forty-one patients were alive (median follow-up: 85 months); 9 patients died perioperatively; 26 patients relapsed. Univariate analysis showed a good outcome correlated with age above 20 years, tumor diameter less than 25 mm, and low-grade histology. Multivariate analysis confirmed histology and tumor volume to be significant independent prognostic factors. The extent of surgery and radiotherapy had no clear influence on survival. CONCLUSIONS: This review highlights the prognostic features of PPT and may help to determine treatment strategies based on radiologic and pathologic characteristics.

Intraoperative unmasking of brain redundant motor sites during resection of a precentral angioma: evidence using direct cortical stimulation.

We report the first observation of real-time intraoperative evidence of a retrocentral redistribution of motor areas with an unmasking of precentral redundant motor sites, before and after, respectively, surgical removal of a precentral arteriovenous malformation using direct electrical stimulation. This study shows large-scale plasticity of the motor function behind the central sulcus as the result of an arteriovenous malformation, the brain's ability to effect short-term unmasking of precentral motor sites after arteriovenous malformation resection, and the existence of redundant precentral and postcentral motor areas for the same movement, suggesting that the central sulcus does not simply divide motor and sensory functions.

[Preoperative direct cortical and sub-cortical electric stimulation during cerebral surgery in functional areas]. / Intérêt des stimulations électriques corticales et sous-corticales directes peropératoires dans la chirurgie cérébrale en zone fonctionnelle.

Indications of surgical treatment for lesions in functional cerebral areas depend on the ratio between the definitive neurological deficit and the beneficial effect of resection. Detection of eloquent cortex is difficult because of important individual variability. Peroperative direct cortical and subcortical electrical stimulations (DCS) provide the most precise and reliable method currently available allowing identification and preservation of neurons essential for motricity, sensitivity++ and language. We report our preliminary experience with DCS in surgery of intracerebral infiltrative tumors with a consecutive series of 15 patients operated from November 96 through September 97 in our institution. Presenting symptoms in the 15 patients (8 males, 7 females, mean age 43 years) were seizures in 11 cases (73%) and neurological deficit in 4 cases (27%). Clinical examination was normal in 11 patients and revealed hemiparesia in 4. Magnetic resonance imaging (MRI) with three-dimensional reconstruction showed a precentral tumor in 10 cases, central lesion in one patient, postcentral lesion in two cases, right insular tumor (non-dominant hemisphere) in one case. All patients underwent surgical resection using DCS with detection in 13 cases of motor cortex and subcortical pathways under genera anesthesia, in one case of somatosensory area under local anesthesia, and in one case of language areas also under local anesthesia. The tumor was recurrent in two patients had been operated earlier but without DCS. Resection, verified by postoperative MRI, was total in 12 cases (80%) and estimated at 80% in 3 patients. Histological examination revealed an infiltrative glioma in 12 cases (8 low grade astrocytomas, 3 low grade oligodendrogliomas, and one anaplastic oligodendroglioma), and metastases in 3 cases. Eight patients had no postoperative deficit, while the other 7 patients were impaired, with, in all cases except one, complete recovery in 15 days to 2 months. Direct cortical and subcortical electrical stimulations offer a reliable, precise and safe method, allowing functional mapping especially useful in case of infiltrative cerebral tumors in eloquent areas. This technique allows improvement in the quality of tumoral resection and concurrently a minimization of the risk of definitive postoperative neurological deficit.

Early rebleeding from intracranial dural arteriovenous fistulas: report of 20 cases and review of the literature.

OBJECT: In this study the authors sought to estimate the frequency, seriousness, and delay of rebleeding in a homogeneous series of 20 patients whom they treated between May 1987 and May 1997 for arteriovenous fistulas (AVFs) that were revealed by intracranial hemorrhage (ICH). The natural history of intracranial dural AVFs remains obscure. In many studies attempts have been made to evaluate the risk of spontaneous hemorrhage, especially as a function of the pattern of venous drainage: a higher occurrence of bleeding was reported in AVFs with retrograde cortical venous drainage, with an overall estimated rate of 1.8% per year in the largest series in the literature. However, very few studies have been designed to establish the risk of rebleeding, an omission that the authors seek to remedy. METHODS: Presenting symptoms in the 20 patients (17 men and three women, mean age 54 years) were acute headache in 12 patients (60%), acute neurological deficit in eight (40%), loss of consciousness in five (25%), and generalized seizures in one (5%). Results of the clinical examination were normal in five patients and demonstrated a neurological deficit in 12 and coma in three. Computerized tomography scanning revealed intracranial bleeding in all cases (15 intraparenchymal hematomas, three subarachnoid hemorrhages, and two subdural hematomas). A diagnosis of AVF was made with the aid of angiographic studies in 19 patients, whereas it was a perioperative discovery in the remaining patient. There were 12 Type III and eight Type IV AVFs according to the revised classification of Djindjian and Merland, which meant that all AVFs in this study had retrograde cortical venous drainage. The mean duration between the first hemorrhage and treatment was 20 days. Seven patients (35%) presented with acute worsening during this delay due to radiologically proven early rebleeding. Treatment consisted of surgery alone in 10 patients, combined embolization and surgery in eight, embolization only in one, and stereotactic radiosurgery in one. Three patients died, one worsened, and in 16 (80%) neurological status improved, with 15 of 16 AVFs totally occluded on repeated angiographic studies (median follow up 10 months). CONCLUSIONS: The authors found that AVFs with retrograde cortical venous drainage present a high risk of early rebleeding (35% within 2 weeks after the first hemorrhage), with graver consequences than the first hemorrhage. They therefore advocate complete and early treatment in all cases of AVF with cortical venous drainage revealed by an ICH.

Three-dimensional computerized tomography in the presurgical evaluation of Chiari malformations.

Malformations of the cranio-cervical junction represent a complex entity, comprising neuro-meningeal and bone anomalies. Malformations of the central nervous system are nowadays easily explored using magnetic resonance imaging (MRI), while osseous malformations are classically assessed with standard radiographic techniques, which can give only incomplete information, and are often difficult to realize and analyse. We report a retrospective study of 10 patients with a Chiari malformation operated on in our department at La Salpêtrière hospital, between July 1995 and December 1996 (1 man, 9 women; mean of age: 35 years; postoperative median follow-up: 6 months; 70% of improvement and 20% of stabilisation), and we underline the interest of the systematic pre-operative realization of a 3D CT and angio-CT studies of the cranio-cervical junction. This examination offers advantages of: a precise analysis of the more complex osseous malformations; a study of the relationships between vascular and bony structures; a study of the relationships between neuraxis and spinal and cranial structures; and an optimal planning of the surgical procedure, adapted to the anatomical particularities of the patient.

Ganglioglioma of the pineal region: case report and review of the literature.

BACKGROUND: Ganglioglioma is a lesion rarely encountered in the pineal region. Only six cases have been published to our knowledge. METHODS AND RESULTS: We present the case of a 38-year-old male suffering from a pineal ganglioglioma that was totally removed by surgery. Histological diagnosis was made by light microscopy using immunostaining for synaptophysin. We review the few radiological and pathological data available in the literature concerning this very rare lesion for which surgery alone provides excellent results. CONCLUSION: The possibility of long term remission obtained by surgery alone and the lack of specificity of clinical and radiological features of ganglioglioma are additional reasons for an aggressive surgical management of pineal tumors when tumor markers and cytopathological examination of the cerebrospinal fluid are not contributive.

Intraoperative direct electrical stimulation of the lamina quadrigemina in a case of a deep tectal cavernoma.

Despite the recent neuro-imaging and microsurgical advances, a high rate of postoperative morbidity still remains in brain stem surgery. We report an original case of cavernous angioma of the right inferior colliculus without extension to the surface, operated on using brain stem electrical stimulations. Peroperative ocular motor responses were obtained, allowing identification of essential neural structures before dissection of the brain stem surface, and accurate definition of the limits between the lesion and functional tissue in depth. Total removal of cavernoma and surrounding gliosis was then performed, with normal postoperative neurological status. As already reported at the cortical level, peroperative direct brain stem stimulations constitute a safe and easy method of functional mapping. A more intensive use of this neurophysiological technique might permit one to extend the indications for brain stem surgery, with minimisation of postoperative morbidity and maximisation of tumour resection.

Early radiologically proven rebleeding from intracranial cavernous angiomas: report of 6 cases and review of the literature.

Although intracranial cavernomas are known to cause haemorrhage, data concerning the frequency, severity and delay of recurrent bleedings are controversial. We report a series of 6 patients with histologically proven cavernoma, presenting with early clinical signs and radiological proof of rebleeding, that is occurring in the first month after initial overt haemorrhage. These 6 cases have been selected from a series of 142 patients seen between 1980 and 1995 in our department with cavernous angiomas or so-called AOVMs, of whom 93 presented with clinical symptoms of haemorrhage (34 patients presented symptoms of one or more rebleeding, but only 6 had radiological proof). All patients suffered neurological worsening due to the rebleeding, with an increase of the size of the haematoma on the CT scan. Five MRIs were performed at the acute stage: 3 showed evidence of cavernoma (60%). All patients underwent surgery at the acute stage of the rebleeding, with 5 improvements and 1 stabilization. A cavernous angioma was found in 5 cases at first surgery, but a further operation was necessary in the last patient to find and remove the cavernoma, after a second rebleeding following the first intervention. Our series reveals a high frequency of rebleeding after a first intracranial haemorrhage from a cavernous angioma, and highlights the precocity of such rebleedings. Therefore, we advocate early aggressive surgical management: in cases of cavernoma revealed by a first clinical overt haemorrhage, when there is strong radiological suspicion at the acute stage; and in all cases of rebleeding, even without radiological evidence of malformation, in the absence of vascular risk factors. Surgical indication must be discussed in particular cases of cavernomas of the brain stem when neither the haematoma nor the cavernoma reach the surface, and in deep supratentorial cavernomas, when the neurological status is good, because of the therapeutic risk.