Michael Bruneau

Positron emission tomography-guided volumetric resection of supratentorial high-grade gliomas: a survival analysis in 66 consecutive patients.

OBJECTIVEIntegrating positron emission tomographic (PET) images into the image-guided resection of high-grade gliomas (HGG) has shown that metabolic information on tumor heterogeneity and distribution are useful for planning surgery, improve tumor delineation, and provide a final target contour different from that obtained with magnetic resonance imaging (MRI) alone in about 80% of the procedures. Moreover, PET guidance helps to increase the amount of tumor removed and to target image-guided resection to anaplastic tissue areas. The present study aims to evaluate whether PET-guided volumetric resection (VR) in supratentorial HGG might add benefit to the patients outcome. METHODSPET images using [18F]fluorodeoxyglucose (n=23) and [11C]methionine (n=43) were combined with MRI scans in the planning of VR procedures performed at the initial stage in 66 consecutive patients (43 M/23 F) with supratentorial HGG according to the technique previously described. In all cases (35 anaplastic gliomas [20 astrocytomas, 10 oligoastrocytomas, 5 oligodendrogliomas] and 31 glioblastomas [GBM]), level and distribution of PET tracer uptake were analyzed to define a PET contour projected on MRI scans to define a final target contour for VR. Maximal tumor resection was accomplished in each case, with the intention to remove the entire abnormal metabolic area comprised in the surgical planning. Early postoperative MRI and PET assessed tumor resection. Survival analysis was performed separately in anaplastic gliomas and glioblastoma multiforme according to the presence or absence of residual tracer uptake on postoperative PET and according to the presence or absence of residual contrast enhancement on postoperative MRI. RESULTSPreoperatively, metabolic information helped the surgical planning. In all procedures, PET contributed to define a final target contour different from that obtained with MRI alone. Postoperatively, 46 of 66 patients had no residual PET tracer uptake (total PET resection), 23 of 66 had no residual MRI contrast enhancement. No additional neurological morbidity due to the technique was reported. A total PET tracer uptake resection was associated with a significantly longer survival in anaplastic gliomas (P = 0.0071) and in glioblastoma multiforme (P = 0.0001), respectively. A total MRI contrast enhancement resection was not correlated with a significantly better survival, neither in anaplastic gliomas (P = 0.6089) nor in glioblastoma multiforme (P = 0.6806). CONCLUSIONSComplete resection of the increased PET tracer uptake prolongs the survival of HGG patients. Because PET information represents a more specific marker than MRI enhancement for detecting anaplastic tumor tissue, PET-guidance increases the amount of anaplastic tissue removed in HGG.

Foramen magnum meningiomas: detailed surgical approaches and technical aspects at Lariboisière Hospital and review of the literature

Foramen magnum meningiomas are challenging tumors, requiring special considerations because of the vicinity of the medulla oblongata, the lower cranial nerves, and the vertebral artery. After detailing the relevant anatomy of the foramen magnum area, we will explain our classification system based on the compartment of development, the dural insertion, and the relation to the vertebral artery. The compartment of development is most of the time intradural and less frequently extradural or both intraextradural. Intradurally, foramen magnum meningiomas are classified posterior, lateral, and anterior if their insertion is, respectively, posterior to the dentate ligament, anterior to the dentate ligament, and anterior to the dentate ligament with extension over the midline. This classification system helps to define the best surgical approach and the lateral extent of drilling needed and anticipate the relation with the lower cranial nerves. In our department, three basic surgical approaches were used: the posterior midline, the postero-lateral, and the antero-lateral approaches. We will explain in detail our surgical technique. Finally, a review of the literature is provided to allow comparison with the treatment options advocated by other skull base surgeons.

Anatomical variations of the V2 segment of the vertebral artery.

OBJECTIVE: Our goal was to evaluate the incidence of anatomic variations of the V2 segment (from its entrance into the transverse canal to C2) of the vertebral artery. Ignoring such variations during anterior or lateral approach to the cervical spine can lead to inadvertent injury and potentially serious complications. METHODS: We studied the course of 500 vertebral arteries on 200 magnetic resonance imaging and 50 contrast-enhanced computed tomographic scans. RESULTS: The vertebral artery entered the C6 transverse foramen in 93.0% of all specimens. An abnormal level of entrance was observed in 7.0% of specimens (35 courses), with a level of entrance into the C3, C4, C5, or C7 transverse foramen, respectively, in 0.2% (n = 1; 2.9% of all anomalies), 1.0% (n = 5; 14.3% of all anomalies), 5.0% (n = 25; 71.4% of all anomalies), and 0.8% (n = 4; 11.4% of all anomalies) of all specimens. Seventeen (48.6%) abnormalities were right-sided and 18 (51.4%) were left-sided. Thirty-one out of 250 patients (12.4%) had a unilateral anomaly and two had a bilateral anomaly (0.8%). In cases of abnormal entrance into the transverse foramen on computed tomographic images (n = 6), the area of the unfilled transverse foramens was significantly smaller than the contralateral filled foramen (P < 0.0001) and was significantly smaller than the filled foramen of all patients at the same level (P < 0.0001). In five patients (2.0%), the vertebral artery formed a medial loop either into an unusually large transverse foramen whose internal border was medial to the uncovertebral joint or into the intervertebral foramen. CONCLUSION: The incidence of anatomic variations of the vertebral artery V2 segment is high. Potentially dangerous conditions can be detected on preoperative imaging.

Balloon-assisted coiling of intracranial aneurysms is not associated with a higher complication rate

IntroductionWithin the neurosurgical literature on intracranial aneurysms, balloon-assisted coiling (BAC) remains controversial when compared to conventional coiling (CC). The aim of this study was to compare our results with BAC and CC over a 4-year period.MethodsDaily interventional neuroradiology has been available since March 2004 in our institution. Between March 2004 and February 2008, 275 patients with 357 aneurysms were treated by an endovascular approach, including 174 patients/204 aneurysms treated by CC (group I) and 80 patients/92 aneurysms treated by BAC (group II). The remaining patients were treated with other endovascular techniques. Indications of BAC were as follow: aneurysms with an unfavourable neck/sac ratio and/or a branch arising from the neck (90.2%), unstable coiling catheter (6.5%), and anticipated aneurysm rupture (3.3%). The clinical charts, procedural data, and angiographic results of groups I and II were compared.ResultsBAC was used in 25.8% (92/357) of all embolized aneurysms and it was successful in 83/92 aneurysms (90%). There was no significant difference in the procedure-related morbidity and mortality rates between group I (2.3% and 1.15%, respectively) and group II (2.5% and 1.25%, respectively). Although retreatment was more frequent in group II (13%) than in group I (11%), the difference was not statistically significant (P = 0.8125).ConclusionWhen BAC is used frequently, it is a safe and effective technique that is associated with complication rates comparable to those of CC. Although BAC is not associated with more stable anatomical results, it should be considered as an alternative therapeutic option for the treatment of broad-based intracranial aneurysms.

Traumatic false aneurysm of the middle meningeal artery causing an intracerebral hemorrhage:case report and literature review

BACKGROUND Traumatic false aneurysms of the meningeal arteries are rare. We report an unusual case of an intracerebral hematoma caused by the rupture of a traumatic aneurysm of the middle meningeal artery. CASE DESCRIPTION A 64-year-old woman suffered a massive spontaneous intracerebral fronto-temporal hemorrhage. Cerebral angiogram revealed a pseudoaneurysm of the middle meningeal artery. At operation, a skull fracture was discovered in the vicinity of the aneurysm. The patient died the day after surgery. CONCLUSION Although rare, traumatic meningeal aneurysms should be considered as a possible cause of cerebral hematoma. Because of their potential morbidity and mortality, they must be detected and treated rapidly.

Antero-lateral approach to the V3 segment of the vertebral artery.

OBJECTIVE: We describe our surgical technique of exposure, control, and transposition of the third segment of the vertebral artery (VA V3 segment). METHODS: The VA V3 segment extends from the C2 transverse foramen to the dura mater of the foramen magnum. It initially courses vertically between the C2 and C1 transverse foramens, then runs horizontally over the atlas groove, and finally obliquely upwards before piercing the dura mater. Exposure of the VA V3 segment through an antero-lateral approach is performed by passing medially to the sternomastoid muscle. After exposure and protection of the spinal accessory nerve, the C1 transverse process is identified below and in front of the mastoid tip. The small muscles that insert on it are cut to expose the C1-C2 portion. The inferior aspect of the horizontal portion is safely separated from the atlas groove by elevating the subperiosteal plane and the superior aspect is freed by a cut a few millimeters above the VA on the occipital condyle. Complete unroofing of the C1 transverse foramen is achieved by resecting the bone while leaving intact the subperiosteal plane. The VA then can be transposed. Venous bleedings during the dissection from periosteal sheath tearing can be controlled by direct bipolar coagulation. RESULTS: The control of the VA V3 segment is essentially used for lesions in the VA vicinity and to improve the surgical exposure at the craniocervical junction level. Indications therefore are tumoral removal, VA decompression, and rarely, nowadays, VA revascularization. CONCLUSION: Perfect knowledge of the anatomy and the surgical technique permits a safe exposure, control, and transposition of the VA V3 segment. This is the first step of many surgical procedures.

Solitaire stent for endovascular treatment of intracranial aneurysms: immediate and mid-term results in 15 patients with 17 aneurysms.

INTRODUCTION The Solitaire stent is the first fully retractable stent for endovascular treatment (EVT) of intracranial aneurysms. The aim of this study was to evaluate its use in a prospective series with mid-term follow-up. METHODS A retrospective review of our prospectively maintained database identified all patients treated with a Solitaire stent. Clinical charts, procedural data, angiographic results were reviewed. RESULTS Between June 2008 and September 2009, 15 patients with 17 wide-necked or fusiform aneurysms (16 unruptured/one ruptured) were identified. EVT was successfully performed in all but one patient in whom the stent was removed because it induced flow reduction in the 1.8-mm parent artery. Among 14 treated patients, 13 had an excellent outcome and one had a good outcome. In this latter patient, the first stent could not be delivered and was changed for another one that was successfully deployed. The patient experienced a thrombo-embolic complication 6 hours after EVT and kept a slight hand paresis. In all cases but one, the stent was thus easily navigated and positioned despite a relative poor visibility. Angiographic results included eight complete occlusions, two neck remnants, and six incomplete occlusions. Six-month control in 14 aneurysms showed 13 complete occlusions and one incomplete occlusion. CONCLUSION The Solitaire stent is useful for EVT of complex intracranial aneurysms because it is fully retractable, easy to navigate and to precisely place. However, it should be used with caution in arteries less than 2mm in diameter.

Anterolateral approach to the V2 segment of the vertebral artery.

OBJECTIVE We describe our surgical technique of exposure and control of the second segment of the vertebral artery (VA V2 segment). Our basic principle is that working in the VA vicinity is more confident under visual control. METHODS The VA V2 segment extends classically in and between the transverse processes from C6 to C2. This segment can be exposed through an anterolateral approach, passing medially to the sternocleidomastoid muscle and laterally to the internal jugular vein. Except in case of anatomic variation, the VA V2 segment is protected by the transverse processes bone, even if a pathological process displaces the VA along its course between them. The safest technique to expose the VA V2 segment then is to reach first the transverse process by cutting the longus colli muscle. Afterward, dividing intertransversary muscles permits exposure of and safely controls the VA by following its course. If required, the VA V2 segment can even be freed by opening the transverse process as far as the dissection is performed in the subperiosteal plane. In fact, the VA V2 segment is surrounded by a venous plexus and a periosteal sheath. This sheath gives a plane out of which the dissection is safe, avoiding troublesome venous bleeding or VA damage. RESULTS This technique is very efficient for degenerative disorders, hour glass tumors, and vascular surgeries. CONCLUSION Exposure and control of the VA V2 segment is safe if anatomy and variations are perfectly known, and if a rigorous step-by-step surgical technique is followed.

Multilevel oblique corpectomies: surgical indications and technique.

OBJECTIVE We describe extensively the multilevel oblique corpectomy technique with its advantages, disadvantages, indications, and biomechanical effects. This procedure is an alternative to the anterior corpectomy. METHODS Multilevel oblique corpectomy can be indicated in spondylotic myelopathy, whether or not it is associated with unilateral radiculopathy. Certain conditions must be fulfilled: anterior compression must be predominant, the spine must be kyphotic or straight, preoperative instability has to be excluded, and intervertebral discs have to be dehydrated and collapsed. resultS The lateral aspect of the cervical spine is reached and the vertebral artery is controlled through a lateral approach. The lateral part of the pathological intervertebral discs is removed. Then, the lateral portion of the vertebral body is drilled to create an 8-mm wide vertical trench. When the posterior cortical bone as well as the superior and inferior end plates are reached, the microscope is moved obliquely to extend the drilling horizontally as long as required, up to the contralateral pedicle if necessary. Next, the posterior cortical bone and the posterior longitudinal ligament are removed to completely decompress the spinal cord. In the case of radiculopathy, the ipsilateral foramen can be completely opened by taking away the uncovertebral joint after its lateral aspect has been separated from the vertebral artery. CONCLUSION The multilevel oblique corpectomy technique allows wide anterior decompression of the spinal cord and complete unilateral nerve root decompression. Using this technique, the spinal stability is preserved and osteoarthrodesis is not required. Spinal motions are preserved and appear close to normal.

Microsurgical cervical nerve root decompression by anterolateral approach.

OBJECTIVE: Cervical radiculopathy caused by a posterolateral soft disc herniation or spondylosis is a common pathology. METHODS: Decompression of a stressed cervical nerve root is a routine neurosurgical procedure. Most of the time it is achieved through an anterior approach and, less frequently, through a posterior approach in specific indications. RESULTS: According to the principles that an anterolateral compression must directly be reached and that working in the vicinity of the vertebral artery is safe under visual control, we developed the anterolateral approach to the cervical intervertebral foramen and the nerve root using a minimally invasive technique to remove the offending process. CONCLUSION: Microsurgical cervical nerve root decompression by anterolateral approach is a minimally invasive technique, permitting one to remove the offending process staightforwardly. The disc and bone resections are minimal. This method avoids osteoarthrodesis or arthroplasty with disc prosthesis. This technique is efficient with good results and low morbidity.