Siamak Asgari

Embolization of Intracranial Arteriovenous Malformations with Ethylene-Vinyl Alcohol Copolymer (Onyx)

BACKGROUND AND PURPOSE: Endovascular therapy of intracranial arteriovenous malformations (AVMs) is increasingly used. However, it is still under discussion which embolic material is optimal. We report our experience in the treatment of AVMs with ethylene-vinyl alcohol copolymer (Onyx). MATERIALS AND METHODS: Between July 2002 and January 2008, brain AVMs were embolized with Onyx in 82 consecutive patients in our department. There were 41 females and 41 males with a mean age of 44.2 years (range, 15–85 years). Clinical presentation included symptoms due to intracerebral hemorrhage (n = 37), seizures (n = 18), nonhemorrhagic neurologic deficits (n = 8), headaches (n = 9), or incidental symptoms (n = 10). According to the Spetzler-Martin scale, 59 AVMs were grades I–II, 16 were grade III, and 7 were grades IV–V. RESULTS: Complete obliteration at the end of all endovascular procedures was achieved in 20/82 patients (24.4%), with an average of 75% (range, 30%–100%) volume reduction. A mean of 2.9 (range, 1–10) feeding pedicles was embolized per patient, whereas an average of 2.6-mL Onyx was used per patient. Procedure-related permanent disabling morbidity was 3.8%, whereas mortality was 2.4%. CONCLUSIONS: The overall initial complete obliteration rate of intracranial AVMs with Onyx embolization is relatively high, compared with other embolic agents, with evidence of stability with time. Morbidomortality rates due to AVM embolization as a single treatment method or as a part of a multimodality treatment should be further assessed regarding the natural course of the disease.

Foramen magnum meningiomas: clinical outcome after microsurgical resection via a posterolateral suboccipital retrocondylar approach.

OBJECTIVEWe analyzed a consecutive series of patients operated for a foramen magnum (FM) meningioma located on the ventral aspect of the medulla oblongata via a posterolateral suboccipital retrocondylar approach with regard to long-term surgical outcome. METHODSClinical data in a consecutive series of 25 patients experiencing a meningioma attached to dura of the anterior or anterolateral FM rim were retrospectively reviewed. RESULTSThe most common symptoms of the 19 women and six men (mean age, 59.2 yr) was cervico-occipital pain (72%) and gait disturbance (32%). Clinical examination revealed gait ataxia in 48% of the patients. As depicted from preoperative magnetic resonance imaging (MRI), dural attachment of the meningioma at the FM rim was anterior in 36% and anterolateral in 64% of cases. Tumor removal was accomplished via a posterolateral suboccipital retrocondylar approach in all patients. A Simpson Grade 2 resection was achieved in 96% of the patients. Permanent surgical morbidity and mortality rates were 8 and 4%, respectively. No tumor recurrence was observed after a mean follow-up period of 6.1 years (range, 1–14 yr) with clinical and MRI examination, and 80% of the patients have regained full daily activity. CONCLUSIONAnterior and anterolateral FM meningiomas that displace the medulla/spinal cord can be safely and completely resected via a posterolateral suboccipital retrocondylar approach. A tumor remnant should be left on critical neurovascular structures in cases with poor arachnoid dissection planes.

Olfactory groove meningiomas: functional outcome in a series treated microsurgically.

SummaryBackground. A systematic investigation of long-term follow-up results after microsurgical treatment of patients harbouring an olfactory groove meningioma, particularly with regard to postoperative olfactory and mental function, has rarely been performed. We reassessed a series of patients treated microsurgically for an olfactory groove meningioma in regard to clinical presentation, surgical approaches and long-term functional outcome. Method. Clinical, radiological and surgical data in a consecutive series of 56 patients suffering from olfactory groove meningioma were retrospectively reviewed. Findings. Presenting symptoms of the 41 women and 15 men (mean age 51 years) were mental changes in 39.3%, visual impairment in 16.1% and anosmia in 14.3% of the patients. Preoperative neurological examination revealed deficits in olfaction in 71.7%, mental disturbances in 55.4% and reduced vision in 21.4% of the cases. The tumour was resected via a bifrontal craniotomy in 36, a pterional route in 13, a unilateral frontal approach in 4 and via a supraorbital approach in 3 patients. Extent of tumour resection according to Simpson’s classification system was grade I in 42.9% and grade II in 57.1% of the cases. After a mean follow-up period of 5.6 years (range 1–13 years) by clinical examination and magnetic resonance imaging (MRI), 86.8% of the patients resumed normal life activity. Olfaction was preserved in 24.4% of patients in whom pre- and postoperative data were available. Mental and visual disturbances improved in 88 and 83.3% of cases, respectively. Five recurrences (8.9%) were observed and had to be reoperated. Conclusions. Frontal approaches allowed better resection of tumours with gross infiltration of the anterior cranial base, tumours extending into the ethmoids or nasal cavity and in cases with deep olfactory grooves. Preservation of olfaction should be attempted in patients with normal or reduced smelling preoperatively.

Transcortical or transcallosal approach to ventricle-associated lesions: a clinical study on the prognostic role of surgical approach

Abstract Most entities in and around the anterior two-thirds of the supratentorial ventricles can be reached via transcortical or transcallosal approach. This study examined the effect of surgical approach on the postoperative neurological outcome. Thirty-eight patients with intra- and periventricular supratentorial lesions were operated on by either frontal transcortical or anterior transcallosal approach. Postoperative diencephalic damage occurred in 22% of patients in the transcortical group and in 36% in the transcallosal group; transient mutism was virtually equivalent in the two groups. Postoperative epilepsy (26%) and subdural fluid collections (30%) occurred only in the transcortical group. The incidence of postoperative hemiparesis was higher in the transcallosal group. There was a high correlation between postoperative Glasgow Outcome Score of 5 and preoperative severity of neurological disease but no correlation between postoperative Glasgow Outcome Score of 5 and location of the lesion or between postoperative clinical course and surgical approach. Surgical outcome of ventricle-associated lesions depends mainly on the severity of preoperative symptoms and not on surgical approach. Additionally, the incidence of postoperative seizures and subdural fluid collections after transcortical surgery is high.

Spinal intradural juxtamedullary cysts in the adult: surgical management and outcome.

OBJECTIVE:Intradural nonneoplastic cysts compressing the spinal cord are rare lesions. We retrospectively analyzed a series of patients harboring this entity with regard to clinical and radiological features, surgical management, and follow-up results. METHODS:In a retrospective study, we reviewed the medical charts, radiological investigations, and follow-up data of 11 women and 10 men (mean age, 43.6 yr) with intradural juxtamedullary spinal cysts, which were consecutively treated microsurgically at our institutions between January 1995 and January 2003. All lesions were approached via a laminectomy, hemilaminectomy, or laminoplasty at the corresponding vertebral levels and histopathologically verified. The patients were routinely scheduled for clinical follow-up 2 and 6 months after surgery. Baseline postoperative magnetic resonance imaging (MRI) was ordered 6 months after surgery. Thereafter, follow-up was performed at 1-year intervals, with neurological examination and MRI. RESULTS:According to presenting symptomatology, two main patient groups could be differentiated: one group with a myelopathic syndrome (10 patients) and another group with a predominant radicular pain syndrome (8 patients). Histopathological examination revealed 16 arachnoid cysts, 4 neuroepithelial cysts, and 1 cervical nerve root cyst. Most arachnoid cysts (12 cases) were located on the dorsal aspect of the thoracic spinal cord. The mean craniocaudal extension of these cysts was 3.7 vertebral levels, and complete resection was performed. In four patients, the arachnoid cyst was situated ventral to the spinal cord and involved up to 17 vertebral levels. These patients had a history of major spinal trauma, and the cyst was generously fenestrated at its greatest circumference as depicted on preoperative MRI scans. The four neuroepithelial cysts and the cervical nerve root cyst were located on the ventral or ventrolateral aspect of the spinal cord, and their maximum sagittal extension was two spinal vertebral levels. Symptoms in all but two patients demonstrated major improvement; in particular, radiating pain disappeared immediately after surgery. There was no cyst recurrence on MRI after a mean follow-up period of 3.2 years. CONCLUSION:Intradural cysts should be considered in the differential diagnosis of lesions causing myelopathy and/or a radicular pain syndrome. Microsurgical resection or generous fenestration in cysts with large craniocaudal extensions effectively ameliorated patients’ symptomatology. A description of the first documented case of a surgically treated intradural cervical nerve root cyst is provided.

Tentorial meningiomas: clinical results in 81 patients treated microsurgically.

OBJECTIVE:Even during the microsurgical era, tentorial meningiomas present a formidable surgical challenge when tumor involves critical neurovascular structures. We report our experience with tentorial meningioma with regard to clinical presentation, diagnostic workup, microsurgical technique, complications, and follow-up results. METHODS:In a retrospective study, we reviewed the medical charts, neuroimaging data, and follow-up data of patients treated microsurgically for tentorial meningioma in our department between January 1989 and June 2002. Patients were routinely scheduled for clinical and radiological follow-up 6 months and 1 year after surgery. Thereafter, follow-up was performed every 1 or 2 years on the basis of the results of each follow-up examination. RESULTS:The main presenting symptoms of the patients (69 women and 12 men) were headache (75%), dizziness (49%), and gait disturbance (46%). The leading neurological signs were gait ataxia (52%) and cranial nerve deficits (28%). Extent of tumor resection was Simpson Grade I in 29 patients, Grade II in 45 patients, Grade III in 1 patient, Grade IV in 4 patients, and unknown in 2 patients. Permanent surgical morbidity and mortality were 19.8 and 2.5%, respectively. Clinical and magnetic resonance imaging follow-up was available in 74 patients for a period ranging from 1 to 13 years (mean, 5.9 yr). Of these, 64 patients (86%) have resumed normal life activity. Seven patients had tumor recurrence and four underwent reoperation. CONCLUSION:Careful preoperative planning of the surgical approach tailored to tumor location and extent is a prerequisite to achieve radical microsurgical tumor resection with minimal morbidity and mortality. Resection of an infiltrated but patent venous sinus is not recommended.

Spontaneous cerebellar hemorrhage—experience with 57 surgically treated patients and review of the literature

The treatment of spontaneous cerebellar hemorrhage is still discussed controversially. We analyzed a series of 57 patients who underwent surgical evacuation of a cerebellar hematoma at our department. Preoperative clinical and radiological parameters were assessed and correlated with the clinical outcome in order to identify factors with impact on outcome. The overall clinical outcome according to the Glasgow Outcome Scale at the last follow-up was good (GOS 4–5) in 27 patients (47%) and poor (GOS 2–3) in 16 patients (28%). Fourteen patients (25%) died. The initial neurological condition and the level of consciousness proved to be significant factors determining clinical outcome (p = 0.0032 and p = 0.0001, respectively). Among radiological parameters, brain stem compression and a tight posterior fossa solely showed to be predictive for clinical outcome (p = 0.0113 and p = 0.0167, respectively). Overall, our results emphasize the predictive impact of the initial neurological condition on clinical outcome confirming the grave outcome of patients in initially poor state as reported in previous studies. The hematoma size solely, in contrast to previous observations, showed not to be predictive for clinical outcome. Especially for the still disputed treatment of patients in good initial neurological condition, a suggestion can be derived from the present study. Based on the excellent outcome of patients with good initial clinical condition undergoing surgery due to secondary deterioration, we do not recommend preventive evacuation of a cerebellar hematoma in these patients.

Recovery of Ophthalmoplegia after Endovascular Treatment of Intracranial Aneurysms

Do patients with a cranial nerve palsy induced by the presence of a neighboring aneurysm recover after coiling? This is, of course, handy information to have when talking to patients. These authors assessed the parameters of aneurysms and their treatments that influence recovery of ophthalmoplegia. Ten of the patients studied had bled whereas 20 patients had unruptured aneurysms. The mean interval between onset of symptoms and coiling was 48 days. Fifty percent of patients recovered clinically but the others had some residual cranial nerve deficits. Patient age, neck size, and time of treatment did not influence prognosis but those with smaller aneurysms had a better outcome. Only the initial degree of symptoms was a significant prognostic factor. BACKGROUND AND PURPOSE: Recovery of aneurysm induced CNP after endosaccular coiling has been reported in the literature. The aim of this study was to assess in detail the parameters that affect the outcome after endovascular treatment of ophthalmoplegic aneurysms due CNP. MATERIALS AND METHODS: Between November 1999 and March 2008, 30 consecutive patients (8 men, 22 women; mean age, 54.9 years) presenting with CNP underwent endosaccular coiling with or without additional use of stents in the parent artery. Subarachnoid hemorrhage was present in 10 patients, whereas 20 patients had unruptured aneurysms. The mean size of the aneurysms was 10 mm. Initial CNP was complete in 11 patients and partial in 19. Mean follow-up after coiling was 19 months. RESULTS: The mean interval between the onset of CNP and aneurysm embolization was 48 days. Fifteen patients (50%) had complete recovery of oculomotor function, 12 had incomplete recovery (40%), and 3 (10%) remained unchanged after treatment. In 4 aneurysms (13.3%), 1 additional embolization was performed, whereas in 4 other aneurysms, 2 additional embolization procedures were necessary. Procedure-related permanent morbidity occurred in 2 patients (6.6%). CONCLUSIONS: Endosaccular coiling is an effective and safe method for the treatment of ophthalmoplegic aneurysms. Age, neck size, and time of treatment do not seem to constitute prognostic factors with respect to CNP recovery, though patients with small aneurysms, unruptured status, and/or location in the posterior circulation showed a tendency for better outcome. The degree of initial CNP was the only statistically significant prognostic factor concerning the final outcome, resulting in better recovery, in case of incomplete initial CNP.

Onyx embolization as a first line treatment for intracranial dural arteriovenous fistulas with cortical venous reflux.

PURPOSE Our purpose was to present our experience regarding embolization of intracranial dural arteriovenous fistulas (DAVFs) with cortical venous reflux using Onyx, a non-adhesive liquid embolic agent. MATERIALS AND METHODS From January 2006 to December 2007, 16 patients (12 men and 4 women) with a mean age of 61 years (range 42 - 78) with an intracranial DAVF with cortical venous reflux underwent at least one transarterial embolization using Onyx. According to the Cognard classification, 2 lesions were grade V, 5 were grade IV, 6 were grade III, 2 were grade IIa+b, and 1 was grade IIb. The clinical presentation included 5 hemorrhagic deficits, 10 non-hemorrhagic manifestations, and 1 patient was asymptomatic. RESULTS Twenty-four embolization sessions were performed in 16 patients with an average of 3 arterial feeders (range 1 - 9) embolized per DAVF. Immediately after embolization, complete occlusion was achieved in 9/16 (56%) patients after the first session. Further postembolization surgical treatment was performed in 3 patients. Partial reperfusion occurred in 1 patient at the time of mean follow-up of 3.7 months (range 0 - 12). Treatment has been completed for 11/16 patients with angiographic cure in 10/11 (91%). An infratentorial bleeding complication related to embolization occurred in one patient with temporary worsening of the patients gait disturbance. At the time of mean clinical follow-up of 4.5 months (range 0 - 12), no procedure-related permanent morbidity was added to our cohort. CONCLUSION According to our experience, embolization of intracranial DAVFs with cortical venous drainage using Onyx is feasible with promising results, indicating stability at the time of mid-term follow-up. In very complex DAVFs additional embolization material might be necessary, and in some cases surgery is warranted.

Intraoperative Measurement of Cortical Oxygen Saturation and Blood Volume Adjacent to Cerebral Arteriovenous Malformations Using Near-infrared Spectroscopy

OBJECTIVEBoth cortical oxygen saturation (SaO2) and cortical blood volume (BV) are related to regional cerebral blood flow. Among a series of patients with cerebral arteriovenous malformations, we examined the problem of hyperemia after embolization/resection or resection with the intraoperative application of near-infrared spectroscopy. METHODSCortical SaO2 and BV (intracapillary total hemoglobin concentrations) were measured, with near-infrared spectroscopy, in areas adjacent to the arteriovenous malformation for 20 patients, before and after resection. The absolute values for both parameters and postexcision/preexcision ratios (P-P ratios) were determined. Data were correlated with multiple clinical and preoperative angiographic parameters. RESULTSBefore resection, the mean SaO2 was 49 ± 16% and the mean BV was 12.65 ± 7.41 mg/ml. After resection, SaO2 increased for 17 of 20 patients and BV increased for 18 of 20 patients. The differences between pre- and postexcision values for both parameters were observed to be statistically significant (P < 0.01). The average P-P ratios were 1.5 ± 0.4 for SaO2 and 1.7 ± 0.4 for BV. Correlation between the P-P ratios for the two parameters was good. The initial BV and the P-P ratios for both SaO2 and BV were exclusively dependent on the extent of preoperative embolization. Postoperatively, two patients developed intracerebral hemorrhage or severe edema. Both demonstrated high P-P ratios for SaO2 (2.3 and 2.1) and BV (1.6 and 2.1). CONCLUSIONIntraoperative near-infrared spectroscopy is able to detect the hyperemic status of adjacent cortex after arteriovenous malformation resection. However, staged therapy with embolization and surgery results in less hyperemia after resection. While two patients with hyperemic complications exhibited very large increases in SaO2 and BV, we cannot refute the normal-perfusion pressure breakthrough theory.