Leonardo Rangel-Castilla

Cerebral pressure autoregulation in traumatic brain injury.

An understanding of normal cerebral autoregulation and its response to pathological derangements is helpful in the diagnosis, monitoring, management, and prognosis of severe traumatic brain injury (TBI). Pressure autoregulation is the most common approach in testing the effects of mean arterial blood pressure on cerebral blood flow. A gold standard for measuring cerebral pressure autoregulation is not available, and the literature shows considerable disparity in methods. This fact is not surprising given that cerebral autoregulation is more a concept than a physically measurable entity. Alterations in cerebral autoregulation can vary from patient to patient and over time and are critical during the first 4-5 days after injury. An assessment of cerebral autoregulation as part of bedside neuromonitoring in the neurointensive care unit can allow the individualized treatment of secondary injury in a patient with severe TBI. The assessment of cerebral autoregulation is best achieved with dynamic autoregulation methods. Hyperventilation, hyperoxia, nitric oxide and its derivates, and erythropoietin are some of the therapies that can be helpful in managing cerebral autoregulation. In this review the authors summarize the most important points related to cerebral pressure autoregulation in TBI as applied in clinical practice, based on the literature as well as their own experience.

Spinal extradural arteriovenous fistulas : a clinical and radiological description of different types and their novel treatment with Onyx

OBJECT Spinal extradural (epidural) arteriovenous fistulas (AVFs) are uncommon vascular lesions of the spine with arteriovenous shunting located primarily in the epidural venous plexus. Understanding the complex anatomical variations of these uncommon lesions is important for management. The authors describe the different types of spinal extradural AVFs and their endovascular management using Onyx. METHODS Eight spinal extradural AVFs in 7 patients were studied using MR imaging, spinal angiography, and dynamic CT (DynaCT) between 2005 and 2009. Special consideration was given to the anatomy, pattern of venous drainage, and mass effect upon the nerve roots, spinal cord, and vertebrae. RESULTS The neuroaxial location of the 8 spinal extradural AVFs was lumbosacral in 1 patient, lumbar in 4 patients, thoracic in 2 patients, and cervical in 1 patient. Spinal extradural AVFs were divided into 3 types. In Type A spinal extradural AVFs, arteriovenous shunting occurs in the epidural space and these types have an intradural draining vein causing venous hypertension and spinal cord edema with associated myelopathy or cauda equina syndrome. Type B1 malformations are confined to the epidural space with no intradural draining vein, causing compression of the spinal cord and/or nerve roots with myelopathy and/or radiculopathy. Type B2 malformations are also confined to the epidural space with no intradural draining vein and no mass effect, and are asymptomatic. There were 4 Type A spinal extradural AVFs, 3 Type B1s, and 1 Type B2. Onyx was used in all cases for embolization. Follow-up at 6-24 months showed that 4 patients experienced excellent recovery. Three patients with Type A spinal extradural AVFs attained good motor recovery but experienced persistent bladder and/or bowel problems. CONCLUSIONS The current description of the different types of spinal extradural AVFs can help in understanding their pathophysiology and guide management. DynaCT was found to be useful in understanding the complex anatomy of these lesions. Endovascular treatment with Onyx is a good alternative for spinal extradural AVF management.

Middle cerebral artery aneurysms: A single-center series comparing endovascular and surgical treatment

OBJECTIVE The optimal treatment for middle cerebral artery (MCA) aneurysms is controversial. MCA aneurysms have been considered more conducive to surgical treatment. Recent technology has led to successful endovascular treatment of MCA aneurysms. The objective of this study was to analyze the outcomes of endovascular and surgical treatment of MCA aneurysms as experienced by a single tertiary center. METHODS We retrospectively reviewed 90 MCA aneurysms in 84 patients treated from 2005 to 2010. They were separated into 2 groups: endovascular coiling, with 50 (59.5%) patients, and surgical clipping, with 34 (40.5%) patients. Outcome was based on complications, procedural morbidity and mortality, clinical and angiographic outcomes, and retreatment rates. Patients were further separated into ruptured and unruptured aneurysm groups. RESULTS Ruptured aneurysms were 10 of 50 (20%) and 9 of 34 (26.5%) patients in the endovascular and surgical groups, respectively. Procedure-related complications were 16% and 0% for the endovascular and surgical groups (P = .01), respectively. Overall rate of complete or near-complete occlusion at angiographic follow-up was 86% and 95% for the endovascular and surgical groups (P = .16), respectively. Proportion of patients with modified Rankin scale of 3 to 6 at 6 months follow-up was 10% and 5.9% for the endovascular and surgical groups (P = .5), respectively. The mean angiographic follow-up was 9.02 months (range 0 to 5.2 years). Retreatment rates were 14% and 0% for the endovascular and surgical groups, respectively (P = .01). CONCLUSIONS In this nonrandomized sample of 90 MCA aneurysms treated with endovascular coiling or neurosurgical clipping, we observed a similar clinical outcome based on the modified Rankin scale and angiographic occlusion. Complication and retreatment rates were higher but not significant for the endovascular group. Both treatment modalities are good alternatives and should be individualized based on aneurysm angioarchitecture and the patients general conditions.

The Role of Endoscopic Third Ventriculostomy in the Treatment of Communicating Hydrocephalus

OBJECTIVE To elucidate the role of endoscopic third ventriculostomy (ETV) in patients with secondary and idiopathic communicating hydrocephalus (HCP). METHODS A series of 36 patients with communicating HCP (21 men and 15 women) were treated by ETV between November 2007 and February 2010. The patients age ranged from 19 to 81 years old (mean 52 years), and had a follow-up of 6 to 36 months (mean 9.2 months). The patients were divided into a group of 29 patients with secondary communicating HCP and a group of 7 patients with normal pressure HCP. Sixteen (44.4%) of the patients had a previous ventriculoperitoneal shunt placement that presented with shunt malfunction. RESULTS The etiology of secondary HCP was subarachnoid hemorrhage, meningitis, trauma, neoplasm, and others. Etiology was not possible to determine in some patients. The outcome of ETV was considered successful in 27/36 patients (75%). A Kaplan-Meier analysis revealed that the successful proportion of ETVs in secondary communicating HCP at 0.5, 1, and 3 months of follow-up was 0.83, 0.8, and 0.77, respectively; in the idiopathic normal pressure HCP group it was 0.83 initially and became stable at 0.66 after the first month. Overall, the successful proportion of ETV in communicating HCP was at 0, 0.5, 1, and 3 months of follow-up was 0.97, 0.83, 0.78, and 0.75. CONCLUSIONS ETV is a good option in the management of secondary communicating HCP, normal pressure HCP, and replacing malfunctioning ventriculoperitoneal shunts. The indications of ETV as a first-line treatment in communicating HCP needs further study; however, results are promising.

Preoperative Onyx embolization of hypervascular head, neck, and spinal tumors. Experience with 100 consecutive cases from a single tertiary center

Background/purpose Preoperative embolization of head, neck, and spinal tumors is frequently used to control tumor bleeding, reduce operative time, and achieve better resection. Numerous embolic materials have been used. The use of the liquid embolic agent Onyx is rapidly increasing but current experience is limited to small case series. Our purpose was to evaluate the indications, techniques, angiographic devascularization, blood loss, outcome, and general efficacy of preoperative tumor embolization with Onyx in a large series. Methods Retrospective analysis of 100 consecutive cases of head, neck, and spinal tumors embolized with Onyx and prospective follow-up. Results 100 patients (63 women, 37 men) were included. Tumors included 39 meningiomas, 23 metastases, 16 parangliomas, five juvenile nasal angiofibromas, five giant cell bone tumors, three Ewings sarcomas, three hemangiomas, three hemangioblastomas, two multiple myelomas, and one osteoblastoma. In all patients, angiographic analysis of the feeding arteries and branches was performed and all embolizations were completed in a single session. Additional materials were used in 28 patients. No mortality or major complications were observed. Minor complications were seen in 11 patients. 85 patients underwent surgery; 79 within the next 48 h and six of them 4–188 days after embolization. Conclusions Embolization of intracranial, head, neck, and spinal tumors with Onyx is effective and safe by a transarterial route or by direct puncture. Onyx penetrates well into the tumor capillary with less arterial catheterization. Studies are necessary to establish long term utility in adjunct or palliative tumor embolization.

Neuroendoscopic Resection of Intraventricular Tumors: A Systematic Outcomes Analysis

Introduction. Though traditional microsurgical techniques are the gold standard for intraventricular tumor resection, the morbidity and invasiveness of microsurgical approaches to the ventricular system have galvanized interest in neuroendoscopic resection. We present a systematic review of the literature to provide a better understanding of the virtues and limitations of endoscopic tumor resection. Materials and Methods. 40 articles describing 668 endoscopic tumor resections were selected from the Pubmed database and reviewed. Results. Complete or near-complete resection was achieved in 75.0% of the patients. 9.9% of resected tumors recurred during the follow-up period, and procedure-related complications occurred in 20.8% of the procedures. Tumor size ≤ 2cm (P = 0.00146), the presence of a cystic tumor component (P < 0.0001), and the use of navigation or stereotactic tools during the procedure (P = 0.0003) were each independently associated with a greater likelihood of complete or near-complete tumor resection. Additionally, the complication rate was significantly higher for noncystic masses than for cystic ones (P < 0.0001). Discussion. Neuroendoscopic outcomes for intraventricular tumor resection are significantly better when performed on small, cystic tumors and when neural navigation or stereotaxy is used. Conclusion. Neuroendoscopic resection appears to be a safe and reliable treatment option for patients with intraventricular tumors of a particular morphology.

Indications and Results of Direct Cerebral Revascularization in the Modern Era

BACKGROUND There has been a progressive decrease in the indications for cerebral revascularization during the past 30 years, particularly with the advance of endovascular techniques. Our objective was to define indications for and evaluate outcomes of patients treated with bypass surgery in the modern endovascular era. METHODS We retrospectively reviewed the charts of all patients who underwent direct cerebral revascularization procedures between January 2006 and March 2013. RESULTS In total, 121 patients underwent 131 direct microsurgical revascularization procedures. The indications for bypass surgery were moyamoya angiopathy (40 patients, 47 bypasses), complex aneurysms (54 patients, 56 bypasses), and occlusive vascular disease (27 patients, 28 bypasses). Revascularization resulted in improvement of symptoms in 77.5% of patients with moyamoya angiopathy (mean clinical follow-up 18.8 months) and 55.5% of patients with occlusive vascular disease (mean clinical follow-up 10.4 months). Among the aneurysm patients treated with revascularization, 81.5% had a favorable outcome (Glasgow Outcome Scale score 4-5) at long-term follow-up (mean clinical followup 18.5 months). CONCLUSIONS Although microvascular cerebral revascularization is no longer performed as commonly as in the past, it remains an essential part of the skill set required to treat select vascular pathologies. Complex aneurysms are the single largest indication for direct bypass procedures. Moyamoya disease is by far the largest indication if indirect bypass procedures are included in the analysis. In experienced hands, the morbidity and mortality of patients undergoing cerebral revascularization procedures are low and long-term outcomes generally excellent.

Endovascular embolization with Onyx in the management of sinus pericranii: A case report

Sinus pericranii (SP) is an uncommon and usually asymptomatic communication between intra- and extracranial venous drainage pathways in which blood flow can circulate bidirectionally through abnormal dilated veins through a skull defect. Diagnosis and evaluation of the venous drainage pattern is important if treatment is contemplated. Cerebral angiography with the use of Dyna CT can be helpful in the diagnosis of SP and its relationship with the skull defect. The authors report what is, to the best of their knowledge, the first case of SP treated by means of endovascular embolization with Onyx.

Coexistent intraventricular abnormalities in periventricular giant arachnoid cysts

OBJECT Arachnoid cysts are congenital lesions that arise during development by splitting of the arachnoid membrane. Large cysts can be adjacent to CSF pathways causing a marked midline shift and hydrocephalus. The association between a large arachnoid cyst and hydrocephalus has been commonly described as being due to a mass effect, but these previous reports have not focused closely on any associated intraventricular abnormalities. METHODS Seven patients who were previously treated with a cystoperitoneal shunt presented with shunt failure, hydrocephalus, and/or cyst expansion. All of these patients had giant arachnoid cysts extending to the periventricular region from the original site, which was the sylvian fissure in 4 patients, and the suprasellar cistern, quadrigeminal cistern, and interhemispheric fissure in 1 patient each. Endoscopic exploration of the ventricular system and cyst fenestration was then performed in all patients. RESULTS The endoscopic findings were obstruction of the cerebral aqueduct by a membrane not related to the cyst in 5 patients, occlusion of the foramen of Monro in 6, septum pellucidum hypoplasia in 2, and occlusion of the cerebral aqueduct by a quadrigeminal arachnoid cyst in 1. Endoscopic procedures performed were septum pellucidum fenestration and/or foraminoplasty in 5 patients, aqueductoplasty in 2, endoscopic third ventriculostomy in 5, fenestration of the lamina terminalis in 1, and direct cystocisternostomy in 1. After the endoscopic procedure, signs and symptoms of increased intracranial pressure and hydrocephalus improved in all patients, with a reduction in size of the cyst and the ventricle. CONCLUSIONS Ventricular abnormalities contributing to hydrocephalus may be associated with arachnoid cysts. These abnormalities may more likely reflect a common origin than a casual relation. Foramen of Monro stenosis and cerebral aqueduct occlusion associated with an arachnoid cyst can be more frequent than has been previously believed. In cases of periventricular giant arachnoid cysts, endoscopic exploration is a good alternative for examining the ventricular system and identifying and treating CSF obstructions caused by and/or related to arachnoid cysts.

Efficacy and Safety of Endoscopic Transventricular Lamina Terminalis Fenestration for Hydrocephalus

BACKGROUND Endoscopic third ventriculostomy (ETV) has become the procedure of choice in the treatment of obstructive hydrocephalus. In certain cases, standard ETV might not be technically possible or may engender significant risk. OBJECTIVE To present an alternative through the lamina terminalis (LT) by a transventricular, transforaminal approach with flexible neuroendoscopy and to discuss the indications, technique, neuroendoscopic findings, and outcomes. METHODS Between 1994 and 2010, all patients who underwent endoscopic LT fenestration as an alternative to ETV were analyzed and prospectively followed up. The decision to perform an LT fenestration was made intraoperatively. RESULTS Twenty-five patients, ranging in age from 7 months to 76 years (mean, 28.1 years), underwent endoscopic LT fenestration. Patients had obstructive hydrocephalus secondary to neurocysticercosis (11 patients), neoplasms (6 patients), congenital aqueductal stenosis (3 patients), and other (5 patients). Thirteen patients (52%) had had at least 1 ventriculoperitoneal shunt that malfunctioned; 6 patients (24%) had undergone a previous endoscopic procedure. Intraoperative findings that led to an LT fenestration were the following: ETV not feasible to perform, basal subarachnoid space not sufficient, or adhesions in the third ventricle. No perioperative complications occurred. The mean follow-up period was 63.76 months. Overall, 19 patients (76%) had resolutions of symptoms, had no evidence of ventriculomegaly, and did not require another procedure. Six (24%) required a ventriculoperitoneal shunt. CONCLUSION Endoscopic transventricular transforaminal LT fenestration with flexible neuroendoscopy is feasible with a low incidence of complications. It is a good alternative to standard ETV. Adequate intraoperative assessment of ETV success is necessary to identify patients who will benefit.