Mechanical properties of fused sagittal sutures in scaphocephaly.

BACKGROUND: Craniosynostosis in newborns is caused by the premature closure of the cranial sutures leading to cranial vault deformity. It results in aesthetic imbalance and developmental disabilities and surgery is frequent during the first months of growth. Our study focused on scaphocephaly defined as the premature closure of the sagittal suture. We hypothesised that the effective mechanical properties of sutures were altered as compared to those of the parietal adjacent tissue considered as control. METHODS: The population consisted of seven males and four females (mean age 4.9 months). Sixteen suture samples and thirty-four parietal tissue samples were harvested during corrective surgery and investigated by using three-point bending tests to obtain the structure-stiffness of specimens. An energy model was used to derive the effective Young's modulus. A histological study complemented the experimental protocol. FINDINGS: Fused sutures were thicker than adjacent bone and the natural curvature of sutures did not influence the static mechanical response. The stiffness of stenotic sutures was significantly higher than that of the parietal bone. The effective Young's modulus of stenotic sutures was significantly lower than that of the parietal adjacent tissue. The parietal tissue showed a parallel bone architecture whereas the central stenotic tissue was disorganised with more vascularisation. INTERPRETATION: The stenotic suture differed in structural and mechanical terms from the adjacent bone during calvarial growth in the first year of life. Our study emphasised the alteration of effective tissue properties in craniosynostosis.

Desmoplastic infantile astrocytoma with benign histological phenotype and multiple intracranial localizations at presentation.

Desmoplastic infantile astrocytoma (DIA) and desmoplastic infantile ganglioglioma (DIG) are rare intracranial tumors that mostly occur in the first 2 years of life and involve superficial cerebral cortex. Despite the large size of these lesions and some worrisome histological and radiological features, prognosis is generally favorable after gross total resection. We report an original observation of a desmoplastic infantile astrocytoma in a 5-year-old boy with multiple localizations on initial presentation, including the unusual subtentorial region. Magnetic resonance imaging showed a temporal tumor with prepontine and interpeduncular extension, and two other distinct localizations in cisterna magna and left cerebellar hemisphere. Leptomeningeal enhancements were present around the basal cistern. The surgical samples, corresponding exclusively to subtentorial lesions, were devoid of anaplastic features; the temporal lesion was untouched because of the interpeduncular extension. Adjuvant chemotherapy was applied, with shrinkage of lesions. DIA and DIG are more generally unifocal at initial presentation. When the tumor is large, multilobular involvement is common, but multiple location of DIG is, on the contrary, very rare. Previously, only five cases of DIG/DIA located in two or more separate locations have been published. We report the sixth, and first noninfantile, case of DIA/DIG with multifocal initial presentation.

Isolated lymphocytic infiltration of pituitary stalk preceding the diagnosis of germinoma in 2 prepubertal children treated with growth hormone.

We report the clinical course of 2 patients with central diabetes insipidus and evolving to panyhypopituitarism which prompted the diagnosis of an isolated pituitary stalk thickening (PST). In both patients, all etiological investigations were normal and the first biopsy revealed an isolated lymphocytic infiltrate with no sign of malignancy. Close clinical follow-up accompanied by serial brain MRIs was proposed to determine a precise diagnosis and for early detection and treatment of neoplastic disease. In our first case, the diagnosis of germinoma was made 9 months after the PST diagnosis owing to tumor progression. In the second case, the time course was even longer with the diagnosis of germinoma 6 years following initial presentation. In these cases, it is speculated that the lymphocytic infiltrates represent the first sign of a host reaction to an occult germinoma. To our knowledge, this is the third case reported of lymphocytic infiltrates preceding a germinoma in a prepubertal girl, and the only case reported in a prepubertal boy. These cases underline the difficulties in establishing the diagnosis of germinoma in a patient with isolated PST.

[Natural history of intramedullary cavernomas. Results of the French Multicentric Study]. / Histoire naturelle des cavernomes intramédullaires et traitement chirurgical. Résultats de l'étude française multicentrique.

INTRODUCTION: The prevalence of cerebral cavernomas is about 0.5% in the general population. In contrast, spinal cord cavernomas are considered as rare. The objective of this study was to determine the natural history of spinal cord cavernomas in a multicentric study. METHODS: Clinical and neuroradiological findings were retrospectively collected. Diagnosis was based on pathological criteria or magnetic resonance (MR) findings. RESULTS: Fifty-three patients were included (26 males, 27 females). Mean age at onset of symptoms was 40.2 years (range: 11-80). Initial symptoms were progressive (32) and acute myelopathy (20). One patient was asymptomatic. Clinical symptoms were related to spinal cord compression (24) and hematomyelia (19). Cavernoma location was dorsal (41) and cervical (12.). MR findings consisted of hyperintense signal on T1 and T2 sequences (19 cases), mixed hyperintense and hypointense signal (33 cases), and hypointense signal on T1 and T2 sequences in 1 case. Mean size was 16.3 mm (range: 3-54). Forty patients underwent surgical resection. Improvement was observed in 20 patients and worsening of neurological symptoms in 11. Length of follow up was 7.1 years. At the end of the study, 26 patients were autonomous, 18 handicapped and 1 bedridden. CONCLUSION: This study provided precise data on the clinical and MR patterns of these lesions. The natural history is associated with a higher risk of hemorrhage recurrence, but is favorable in many operated patients. Microsurgery is the treatment of choice for most of these lesions.

Immunodetection of SV40 large T antigen in human central nervous system tumours.

BACKGROUND/AIMS: DNA sequences from Simian virus 40 (SV40) have been previously isolated from various human tumours of the central nervous system (CNS). This study aimed to investigate a series of tumours of the CNS for the expression of the SV40 large T antigen (Tag), which is an oncogenic protein of the virus. METHODS: A French series of 82 CNS tumours was investigated for Tag expression using a monoclonal antibody and immunohistochemistry. A Tag positive hepatocellular carcinoma cell line from transgenic mice and a kidney biopsy from a patient infected by SV40 were used as positive controls. RESULTS: None of the tumours (20 ependymomas, 20 glioblastomas, 12 oligodendrogliomas, three plexus choroid adenomas, two plexus choroid carcinomas, 15 meningiomas, and 10 medulloblastomas) contained SV40 Tag positive cells. CONCLUSIONS: The lack of SV40 Tag in 82 CNS tumours of various types is at variance with previous studies from different countries, and suggests that the virus may not be an important factor in CNS tumorigenesis, at least in French cases.

Posterolateral approach and anterior spinal canal recalibration in severe spinal injury affecting T-12, L-1: a study of seven cases.

The authors present seven cases of spinal trauma at the T-12--L-1 level with severe spinal canal stenosis secondary to compressive, anterior discocorporeal lesions. Associated neurological disorders were of varying severity. Six cases were investigated by computed tomography, which enabled the degree of thoracolumbar spinal canal stenosis to be determined. In all cases, the surgical procedure involved rectification of spinal deformity, with an initial unilateral posterolateral approach permitting anterior spinal canal recalibration, either by impaction of protrusive fragments or ablation of ejected disc fragments. The stabilization was in all cases achieved by complimentary bilateral plates using Roy-Camille material, associated with posterolateral arthrodesis by grafting with reconstruction of the articulopedicular structure. The functional spinal result was excellent in all cases, and recalibration was verified by tomography. In those cases showing neurological deficiency, good and early recovery was attributable to the suppression of spinal canal stenosis. The application of this posterolateral approach for severe lesions of the thoracolumbar junction seems to represent, in all cases of recent lesions, an alternative to the anterior or combined methods, which present widely recognized difficulties at the thoracoabdominal junction.

[Pseudotumor forms of neurosarcoidosis in children. Diagnostic difficulties and therapeutic management]. / Formes pseudo-tumorales de la neurosarcoïdose chez l'enfant. Difficultés diagnostiques et prise en charge thérapeutique.

In systemic sarcoidosis, neurologic manifestations are possible and occurred in 5 p. 100 of cases. The diagnosis is easier when sarcoiddosis is known, but in half case neurologic symptoms are inaugural. In these cases, involvement of other sites (liver, lung, eyes or skin) by the disease is needed to confirm sarcoidosis. Main manifestations in neurosarcoidosis are cranial nerve palsy, diabetes insipidus or chronic aseptic meningitis, but sometimes sarcoidosis can present as an intracranial mass. The diagnosis of neurosarcoidosis may be difficult and could be confused with infection (such tuberculosis or mycosis), with inflammatory diseases (such multiple sclerosis) or with neoplasm, particularly in case of oedema. Brain biopsy may be necessary in isolated neurosarcoidosis if no peripheral histology evidence of noncaseating granulomas has been obtained. Treatment with steroids alone is the best choice for initial therapy but must be prolonged. It is difficult to predict accurately the response to steroids and relapse may be possible after a long time. Other immunosuppressive therapeutics or radiotherapy have been used in patient with refractory neurosarcoidosis. Sequential magnetic resonance imaging is the useful mean for the follow-up of neurosarcoidosis.

[Complications of the intravascular treatment of intracranial aneurysms using metal microcoils. Embolization using coils in intracranial aneurysms]. / Complications du traitement endovasculaire des anévrysmes intracrâniens par micro-spires métalliques. Embolisation par coils des anévrysmes intracrâniens.

Embolization of intracranial aneurysms with coils. The authors present the results and complications of microcoils embolization of intracranial aneurysms in 28 patients. Fibers platinum microcoils were used (Target Therapeutic) 28 patients (males: 6, females: 22; mean age: 51 years) were treated, 27 suffered from sub-arachnoid hemorrhage (SAH) and one presented with a pseudotumoral syndrome (giant aneurysm). All patients were evaluated on the day of treatment, according to the World Federation of Neuro-Surgeon classification (W.F.N.S.) of SAH and after 4 months of follow-up. At a mean follow-up period of 4 months, according to Glasgow Outcome Scale (G.O.S.) there were 13 cases of good results, 5 cases of "moderate disability", 2 cases of "severe disability", 2 cases of "vegetative state" and 6 deaths. Complications were observed in 11/28 cases. Coils migration and malposition in the parent artery were linked to the procedure (mechanical detachable coil) and resulted in severe deficit (one case), transient disability (one case) or went unnoticed (4 cases). Primary or secondary complete occlusion was achieved in 8/28 patients (32%). A majority of cases (11 cases) ended with stable residual aneurysmal sac lumen while rebleeding occurred in 3 patients and was responsible for 2 deaths. In the third case a favourable outcome was obtained after balloon occlusion of the parent artery.

[Association of venous angioma and cavernoma of the posterior fossa]. / Association d'un angiome veineux et d'un cavernome au niveau de la fosse postérieure.

BACKGROUND: Association of venous angioma to cavernous malformation is rare. If bleeding occurs, it must be assigned to the cavernous malformation. CASE REPORT: A 4 year-old boy suffered from an acute ataxia. Investigation showed a venous angioma and a cavernoma malformation in the posterior fossa. The patient was admitted again at the age of 8 years for a new episode of acute ataxia due to cerebellar hematoma. A conservative treatment was settled because of the risk of venous infarction. CONCLUSION: Venous angiomas are rarely symptomatic and are considered as normal venous variants. Indeed, the cavernomas are true malformations with a high bleeding potential. When both lesions are associated and bleeding occurs, only the cavernous malformation has to be removed if surgically accessible.

[Clear cell meningioma: recurrent intraspinal tumor in a child]. / Méningiome à cellules claires: tumeur rachidienne récidivante chez un enfant.

BACKGROUND: Meningiomas represent 1.5% to 4.3% of cerebral and medullar primary tumors in children. CASE REPORT: A 9-year-old girl had a history of thoracolumbar scoliosis. An intracanalar and extramedullar tumor was confined to the lumbar region. Resection identified a clear cell meningioma. A symptomatic and tumoral recurrence occurred 5 months later in the same region. After a second resection, the patient received radiotherapy. At 8 months follow-up, no recurrence was documented. CONCLUSIONS: A stiff and painful scoliosis can be predictive of expansive intracanalar tumor. The recurrent or multifocal evolution of clear cell meningioma show the "aggressive behavior" of this histological type. A preventive radiotherapy could be proposed, depending on the age of the patient and the localization of the tumor.

[Value of the study of somatosensory evoked potentials during surgical correction of scoliosis associated with syringomyelia. Apropos of 4 cases]. / Intérêt de l'étude des potentiels évoqués somesthésiques au cours de la correction chirurgicale des scolioses associées à une syringomyélie. A propos de quatre observations.

PURPOSE OF THE STUDY: The presence of a syringomyelia cavity increases the rate of neurological complications on the course of surgical treatment of scoliosis. We have evaluated the results of monitoring of somatosensory evoked potentials (SEP) in these situations. MATERIAL AND METHODS: Four patients presenting a scoliosis associated with syringomyelia have been operated through a posterior-approach with CD instrumentation. SEP monitoring was performed pre and intraoperatively. We studied the latency and the amplitude of P40. RESULTS: Preoperative SEP showed in all cases posterior spinal cord involvement (even without clinical manifestations). During monitoring, we noted in one case no variation. In one case a flattening of the response with normalisation within 5 minutes. In two cases a persistent flattening with normalisation within 10 and 15 minutes following modification of the instrumentation. In all cases, postoperative neurological status was identical to preoperative one. DISCUSSION: Preoperative SEP can make the diagnosis of posterior spinal cord involvement even when clinical status is normal. The extent of the preoperative SEP abnormalities may preclude the risk of intraoperative neurological complications. Intraoperative SEP can be performed with the same anesthetic protocol and the same technique used when operating idiopathic scoliosis. The results seem reliable. When alteration occur as for idiopathic scoliosis alteration of the amplitude appears earlier than alteration of the P40 latency. Restoration of normal responses appears later than in idiopathic scoliosis. CONCLUSION: SEP monitoring should diminish the risk for neurological complications in the course of surgical treatment of scoliosis associated with syringomyelia.

[Contribution of computer tomography in recent traumatology of the spine. Apropos of 31 cases]. / Apport de la tomodensitométrie en traumatologie récente du rachis. A propos de 31 observations.

The authors report 31 cases of recent spinal injury (14 cervical, 17 thoraco-lumbar) which have been investigated using computerized tomography. After a critical appreciation of the conventional approach to such lesions, the authors consider the advantages and limitations of computerized tomography. Analysis of the data from 31 cases studies confirms that this technique has considerable applications in the assessment of corporeo-discal and pediculo-lamar lesions and, in particular in the determination of the degree of spinal canal stenosis and in the detection of actual potential neuroaggressive factors which are important for the choice of therapy. Computerized tomography provides information which is essential in choosing the surgical strategy to be adopted in each case, and in particular allows determination of the best approach and of the time scale for successive operations in the case of a double approach. On the other hand, computerized tomography alone does not permit precise determination, either of the degree of instability of spinal lesions or of the magnitude of static deformations.

[Effects of cranioplasty on neurological function and cerebral blood flow]. / Incidence des crânioplasties sur la fonction neurologique et le débit sanguin cérébral.

The authors present a review of their experience of cranioplasty in cases showing of skull defects. Forty recent case reports were retained out of a total of 125 cases and of these, 15 showed neurological deficiency prior to cranioplasty. In 7 out of these 15 cases cranioplasty appeared to have no effect, but in the 8 remaining cases, an improvement in the neurological condition was observed. In connection with these clinical observations, a recent study of a small group of patients with skull defects used the Xenon 133 inhalation method to investigate cerebral blood flow. In all cases these was a significant postoperative improvement in cerebral blood flow. The rate varying from 15 to 30% and this improvement was even observable in the case of small skull defects of the order of 10 cm2. The mechanism giving rise to such improvements is discussed; it may be related to cerebral hemodynamic normalization after skull restoration. The improvement in cerebral blood flow brought about by cranioplasty in all the cases studied suggests that this technique may be important not only for simple skull repair but also to improve neurological function.

[French neurosurgery in the Bosnia-Herzegovina conflict]. / Les missions neurochirurgicales françaises dans le conflit en Bosnie-HerzEgovine.

Seven French neurosurgical missions, from June 1994 to December 1996, were sent successively to Bosnia-Herzegovina with the help of a non-governmental organisation Médecins du Monde. The aim of this article is to present the working conditions, make an overall evaluation of the missions and then to draw lessons and discuss the limits. The initial aim of these neurosurgical missions was: i) to provide human and logistic support to the Bosniac teams in the field; ii) to exchange knowledge and help in the training of local young neurosurgeons; iii) to be present as witnesses. The towns of Tuzla and Zenica in Eastern and Central Bosnia respectively were chosen as the missions bases. One hundred five neurosurgical operations were carried out in precarious conditions, particularly concerning anesthesia. The largest number of the operations (52%) concerned standard neurosurgical pathologies, without any direct link to the war but which had been put off or made difficult due to the war. Cranioplasties and peripheric nerve injuries were the main lesions directly related to the war situation which the French missions had to deal with. Actually, war neurosurgical pathologies were very often dealt with in emergency by Bosniac teams in the field hospitals near the front. Previously existing neurosurgical environment, in particular with access to a scanner is an absolute necessity to carry out a good quality neurosurgical mission. Precarious anesthesia and operating conditions require the surgical team to adapt to local conditions, but are not a contra-indication to such missions. Although help in the field can prove useful on occasions, training the resident teams is important. This can be done locally, but additional training in a neurosurgically developed country is fundamental. Missions such as these require relatively major funding (about 150 000 French francs for each of our missions) and suitable infrastructures. Prior to undertaking this type of mission, a neurosurgeon must evaluate local human and equipment needs.

[Foraminal and latero-foraminal hernia. Mid-term results of percutaneous techniques nucleolysis-nucleotomy]. / Hernies foraminales et latéroforaminales. Résultats à moyen terme des techniques percutanées nucléolyse-nucléotomie.

Forty cases of foraminal (28) and lateroforaminal (12) herniated discs treated either by nucleolysis (N.L.) or percutaneous automated nucleotomy (P.A.N.) were investigated over a period of 12 months or more. The group of patients treated with P.A.N. (15 males, 5 females) with a mean age of 41.8 years, had severe radicular pain in 25% of cases, caused by foraminal (15 cases) and lateroforaminal (5 cases) herniated discs which were predominantly located at the L4-L5 level (12 cases). The group of patients treated with N.L. (13 M, 7 F) with a mean age of 50.3 years complained of severe radicular pain in 65% of cases, caused by foraminal (13 cases) and lateroforaminal (7 cases) disc herniations evenly distributed over the last three mobile segments. The overall results obtained with N.L and P.A.N. showed a 67.5% success rate. The best results were obtained in cases of cruralgia with severe radicular pain caused by foraminal herniated disc at the L3-L4 or L4-L5 levels. A significantly better result was obtained in the group of patients treated by N.L. (80% success rate) than in the group of patients treated by P.A.N. (p < 0.04).

One-step primary reconstruction for complex craniofacial resection with PEEK custom-made implants.

PURPOSE: Reconstruction of large craniofacial defects has largely improved since custom-made implants have been developed in the past decade. For large lesions in fronto-orbital region (such as osteomeningioma), we applied a simple and reliable protocol to perform optimal primary reconstruction with PEEK (polyetheretherketone) specific implant at the same time of the resection. MATERIAL AND METHODS: Our protocol is based on virtual preoperative surgery with a planned bone resection that allows engineering of a specific implant to accurately fit to the defect during the surgery. Thus tumour removal and optimal immediate reconstruction are performed easily in a single-step procedure. The use of navigation is required to perform accurate resection according to the planning. We report our experience in five patients requiring complex orbito-frontal reconstruction. RESULTS: Planned resection was always achieved with accurate placement of the implant. Optimal orbital reconstruction is allowed and permits exophthalmos correction and orbital contour symmetry. No major complication was observed. CONCLUSION: We provide a simple one-step technique to reconstruct the orbit while achieving symmetric cosmetic and functional results, reducing operative time and avoiding donor site morbidity.

Prenatal diagnosis of craniosynostosis: value of MR imaging.

INTRODUCTION: The aim of our study was to assess the utility and reliability of magnetic resonance imaging (MRI) in antenatal diagnosis of craniosynostosis. METHODS: We retrospectively reviewed the MRI examinations of the head of 15 fetuses requested over a period of 11 years on the basis of sonographic suspicion of craniosynostosis. The postnatal diagnosis was available for 14 neonates. RESULTS: No termination of pregnancy was performed. There were four neonates with sporadic multisuture craniosynostoses, three of which were syndromic, including one Crouzon and one Pfeiffer syndrome. Eight neonates were normal, two showed cranial vault deformities without synostosis, and one was lost to follow-up. MRI showed a high predictive value for craniosynostosis, as there were no false-negative or false-positive diagnoses. However, the severity of the abnormalities were underestimated in two neonates. CONCLUSION: We suggest that prenatal MRI has diagnostic value when synostosis is suspected on ultrasonography. Moreover, MRI is accurate in the detection of associated brain abnormalities, which is an important prognostic issue in this diagnosis. Prenatal diagnosis of craniosynostosis is difficult and could benefit from three-dimensional ultrasonography and three-dimensional CT.