Ray M. Chu

Outcomes after aneurysm rupture during endovascular coil embolization

OBJECTIVEIntracranial aneurysm rupture during placement of Guglielmi detachable coils has been reported, but the management and consequences of this event have not been extensively described. We present our experience with this feared complication and report possible neuroradiological and neurosurgical interventions to improve outcomes. METHODSWe retrospectively reviewed the records for 701 patients with 734 intracranial aneurysms that were treated with endovascular coiling, during a 6-year period, in the metropolitan Minneapolis-St. Paul (Minnesota) area. This analysis revealed 10 cases of perforation during coiling. The management and outcomes were recorded, and the pertinent literature was reviewed. RESULTSAll 10 cases involved previously ruptured aneurysms. This complication occurred sporadically and was not observed in the first 100 cases. Perforation occurred during microcatheterization of the aneurysm in two cases and during coil deposition in eight cases. Seven of the perforated aneurysms were located in the anterior circulation and three in the posterior circulation. Six of the 10 patients made good or fair recoveries; all three patients with posterior circulation lesions died immediately after rehemorrhage. Elevated intracranial pressure (ICP) was noted for all five patients with intraventricular catheters in place. Bilateral pupil dilation and profound hemodynamic changes were noted for eight patients. Coiling was rapidly completed, and total or nearly total occlusion was achieved in all cases. Emergency ventriculostomy was performed to rapidly reduce increased ICP for two patients, both of whom made good recoveries. Hemodynamic and angiographic factors after perforation, such as prolonged systemic hypertension, persistent dye extravasation after deployment of the first Guglielmi detachable coil, and persistent prolongation of contrast dye transit time (suggesting ongoing ICP elevation), were correlated with poor outcomes. CONCLUSIONPreviously ruptured aneurysms seem to be more susceptible to endovascular treatment-related perforation than are unruptured lesions. Worse prognoses are associated with iatrogenic rupture during coiling of posterior circulation lesions, compared with those in the anterior circulation. When perforation is recognized, the definitive treatment seems to be reversal of anticoagulation therapy and completion of Guglielmi detachable coil embolization. Immediate neurosurgical intervention is limited in these cases and focuses on decreasing ICP via emergency ventriculostomy. However, these measures may be life-saving, and neurosurgical assistance must be readily available during treatment of these cases.

Application of Diffusion Tensor Imaging to Magnetic-Resonance-Guided Brain Tumor Resection

Interventional magnetic resonance imaging (MRI) continues to make a profound impact on the practice of neurosurgery. We describe a new MRI modality, diffusion tensor imaging (DTI), which uses the diffusion energy of water to map white matter fibers. DTI has been established in other disorders such as metabolic, demyelinating and ischemic diseases. We describe the use of DTI in identifying white matter tracts such as optic radiations and avoiding them intraoperatively in 2 children with low-grade glial tumors.

Focal Intracranial Infections Due to Propionibacterium acnes: Report of Three Cases

OBJECTIVE AND IMPORTANCE Except for its role in shunt infections, Propionibacterium acnes has been of little interest to neurosurgeons. The rarity and indolent nature of focal intracranial infections by P. acnes limit their recognition. Three cases of serious intracranial infection due to this organism are described. CLINCAL PRESENTATION Three patients with histories of immunosuppression and neurosurgical procedures developed nonspecific, delayed presentations (5 wk to 5 yr after surgery) of intracranial infections. In two patients, radiological investigations showed enhancing lesions that were later found to be brain abscesses. A subdural empyema was found in the third patient. INTERVENTIONAll three patients underwent surgical drainage of the purulent collections. P. acnes was isolated in each case, and each patient was treated with a 6-week course of intravenous penicillin. All three patients made good recoveries, and subsequent imaging showed no recurrence of the infectious collections. CONCLUSIONP. acnes is an indolent organism that may rarely cause severe intracranial infections. This organism should be suspected when an intracranial purulent collection is discovered in a patient with a history of neurosurgical procedures. Immunosuppressed patients may be susceptible to this otherwise benign organism. Surgical drainage and treatment with intravenous penicillin should be considered standard therapy.

Intraoperative Magnetic Resonance Imaging-Guided Neurosurgery

Over the last decade, neurosurgeons have become increasingly reliant on image guidance to perform surgery more safely, efficiently, and cost-effectively. Neuronavigational systems are either frame based or frameless and rely on the acquisition of computed tomography or magnetic resonance (MR) imaging (MRI) scans that are obtained either a few days or immediately before surgery to generate a 3-dimensional coordinate set. Unfortunately, neuronavigational systems do not allow the neurosurgeon to adjust for dynamic changes that occur during surgery such as brain shift. More recently, intraoperative MR (iMR) imaging systems have been developed and implemented to treat neurosurgical diseases. These systems consist of a low-field (0.12 or 0.23 T), midfield (0.5 T), or high-field (1.5 T) MR imaging scanner located in an environment that allows general anesthesia to be administered. The main advantage of iMR imaging is the excellent soft tissue discrimination and 3-dimensional visualization of the operative site. Enhanced visualization of an intracranial target allows for a safe surgical trajectory to be chosen that avoids critical structures, the determination of the extent of the tumor resection, and the exclusion of intraoperative hemorrhage. All iMRI systems can provide the neurosurgeon with basic T1- and T2-weighted imaging sequences. High-field MRI systems can also perform advanced functional capabilities such as MR spectroscopy, functional MR imaging, MR venography (MRV), MR angiography (MRA), chemical shift imaging, and diffusion-weighted imaging, however. These MR imaging sequences can provide additional information that may facilitate the success of the operative procedure. Identifying critical vascular structures with MRV and MRA may prevent their inadvertent injury during surgery. Locating an area of elevated choline level within a tumor at the time of biopsy may enhance the diagnostic yield of the procedure. Mapping out areas of neurologic function may influence the choice of the surgical approach to a tumor. In addition to using iMRI to resect tumors, it can be used for placement of deep brain stimulators for Parkinson disease, for the performance of psychosurgery for obsessive-compulsive disorder, or for the treatment of common neurosurgical diseases such as hydrocephalus.

Subdural empyema in children

Subdural empyema (SDE) is generally a disease of children and adolescents. The lack of specific findings in a child with SDE may lead to a rapidly fatal outcome as the result of a delay in diagnosis and treatment. The advent of newer imaging modalities, such as magnetic resonance imaging (MRI), and antibiotics has resulted in improved outcomes. This article reviews the current strategies for diagnosis and treatment of this condition. Current articles on SDE were reviewed and summarized. An overview is presented, followed by an emphasis on causation, pathogenesis, patient presentation, differential diagnosis, and treatment. The approach currently used at this institution for the management of pediatric patients with SDE is also described. Sinus and ear infections, trauma, intracranial surgery, and dental caries account for most cases of SDE. The clinician must be highly suspicious of SDE in the febrile child with neurologic signs and a recent history of ear or paranasal sinus infections. Aerobic and anaerobic streptococci are the most frequent causative organisms cultured from this infection. No definitive guidelines exist regarding duration of treatment, but most series report 2 to 6 weeks of intravenous antibiotics. Arguments have persisted over the use of burr hole drainage versus craniotomy for evacuation of subdural pus. The type of surgical procedure has little impact on the outcome, provided that it is performed early and allows for complete evacuation of the pus. The preoperative neurologic status, age of the patient, and time from presentation to treatment are the most significant determinants of outcome. Early diagnosis, early evacuation, and early use of antibiotics are the fundamental principles of SDE management.

High-field functional capabilities for magnetic resonance imaging-guided brain tumor resection

Abstract:Magnetic resonance imaging (MRI) has had a tremendous impact on neurosurgery, particularly for patients with brain tumors. Originally a diagnostic instrument, MRI technology recently has been incorporated into the neurosurgical operative setting. High-field (1.5-Tesla) systems offer imaging

Delayed Cerebrovascular Complications of Intrathecal Colloidal Gold

OBJECTIVE Therapy with intrathecal colloidal gold has been used in the past as an adjunct in the treatment of childhood neoplasms, including medulloblastoma and leukemia. We describe the long-term follow-up period of a series of patients treated with intrathecal colloidal gold and emphasize the high incidence of delayed cerebrovascular complications and their management. METHODS Between 1967 and 1970, 14 children with posterior fossa medulloblastoma underwent treatment at the University of Minnesota. Treatment consisted of surgical resection, external beam radiotherapy, and intrathecal colloidal gold. All patients underwent long-term follow-up periods. RESULTS Of the 14 original patients, 6 died within 2 years of treatment; all experienced persistent or recurrent disease. The eight surviving patients developed significant neurovascular complications 5 to 20 years after treatment. Three patients died as a result of aneurysmal subarachnoid hemorrhage, and five developed ischemic symptoms from severe vasculopathy that resembled moyamoya disease. CONCLUSION Although therapy with colloidal gold resulted in long-term survival in a number of cases of childhood medulloblastoma, our experience suggests that the severe cerebrovascular side effects fail to justify its use. The unique complications associated with colloidal gold therapy, as well as the management of these complications, are presented. We recommend routine screening of any long-term survivors to exclude the presence of an intracranial aneurysm and to document the possibility of moyamoya syndrome.

Post-irradiation lumbosacral radiculopathy associated with multiple cavernous malformations of the cauda equina: Case report and review of the literature

Background: Multiple radiation-induced cavernous malformations of the cauda equina are extremely rare. A review of the literature suggested that the post-irradiation lumbosacral radiculopathy in our patient was most likely associated with a diagnosis of multiple radiation-induced cavernous malformations of the cauda equina. Case Description: A 76-year-old man with a remote history of abdominal radiation therapy presented with a 6-month history of progressively worsening right foot drop and balance impairment. Magnetic resonance imaging (MRI) revealed multiple enhancing areas of the cauda equina concerning for carcinomatous meningitis, however, cerebrospinal fluid (CSF) analysis was unrevealing. Intraoperative findings were consistent with multiple radiation-induced cavernous malformations of the cauda equina. Conclusions: Multiple radiation-induced cavernous malformations of the cauda equina may mimic carcinomatous or infectious meningitis. Clinicians should be suspicious of this diagnosis when CSF and MRI findings are inconsistent with metastatic disease or infectious meningitis in patients who present with radiculopathy and a history of radiation therapy.

Adult Brainstem Glioblastoma Multiforme: Long-term Survivor

Adult, malignant brainstem gliomas are rare entities that often cause treatment conundrums due to the difficulty of surgical resection and, therefore, the absence of pathological diagnosis. This leads to a reliance on radiological imaging for diagnosis, which can often be unreliable. These shortcomings have made the treatment of brainstem gliomas challenging with unpredictable outcomes. The mainstay of treatment consists of chemotherapy and radiation; however, recurrence is inevitable. Predicting outcomes has been the major difficulty in treating these patients as adult malignant brainstem gliomas Grade II have a median survival between five to seven years while Grades III and IV are between 10-17 months (with some studies showing significantly longer survival in Grade III). Here, we present the case of a patient with the pathologic diagnosis of a right brachium pontis glioblastoma who had a remarkable survival of 73 months, whereas the expected median survival for these patients is 10-17 months.