Martin M. Mortazavi

The intracranial arachnoid mater: A comprehensive review of its history, anatomy, imaging, and pathology

IntroductionThe arachnoid mater is a delicate and avascular layer that lies in direct contact with the dura and is separated from the pia mater by the cerebrospinal fluid-filled subarachnoid space. The subarachnoid space is divided into cisterns named according to surrounding brain structures.MethodsThe medical literature on this meningeal layer was reviewed in regard to historical aspects, etymology, embryology, histology, and anatomy with special emphasis on the arachnoid cisterns. Cerebrospinal fluid dynamics are discussed along with a section devoted to arachnoid cysts.ConclusionKnowledge on the arachnoid mater and cerebrospinal fluid dynamics has evolved over time and is of great significance to the neurosurgeon in clinical practice.

The ventricular system of the brain : a comprehensive review of its history, anatomy, histology, embryology, and surgical considerations

IntroductionThe cerebral ventricles have been recognized since ancient medical history. Their true function started to be realized more than a thousand years later. Their anatomy and function are extremely important in the neurosurgical panorama.MethodsThe literature was searched for articles and textbooks of different topics related to the history, anatomy, physiology, histology, embryology and surgical considerations of the brain ventricles.ConclusionHerein, we summarize the literature about the cerebral ventricular system.

The choroid plexus: a comprehensive review of its history, anatomy, function, histology, embryology, and surgical considerations

IntroductionThe role of the choroid plexus in cerebrospinal fluid production has been identified for more than a century. Over the years, more intensive studies of this structure has lead to a better understanding of the functions, including brain immunity, protection, absorption, and many others. Here, we review the macro- and microanatomical structure of the choroid plexus in addition to its function and embryology.MethodThe literature was searched for articles and textbooks for data related to the history, anatomy, physiology, histology, embryology, potential functions, and surgical implications of the choroid plexus. All were gathered and summarized comprehensively.ConclusionWe summarize the literature regarding the choroid plexus and its surgical implications.

The intracranial bridging veins: a comprehensive review of their history, anatomy, histology, pathology, and neurosurgical implications

IntroductionThe intracranial bridging veins are pathways crucial for venous drainage of the brain. They are not only involved in pathological conditions but also serve as important landmarks within neurological surgery.MethodsThe medical literature on bridging veins was reviewed in regard to their historical aspects, embryology, histology, anatomy, and surgery.ConclusionKnowledge on the intracranial bridging veins and their dynamics has evolved over time and is of great significance to the neurosurgeon.

Pediatric traumatic carotid, vertebral and cerebral artery dissections: a review

Traumatic cerebral dissections are rare but potentially dangerous conditions that through improved diagnostics have recently gained increased interest. However, there is still a significant lack of knowledge on the natural history, as well as on the best treatment options. Most of the literature on this topic consists of case reports and retrospective studies with no prospective randomized controlled studies. In our review, we highlight the fact that there is no level 1 evidence for the natural history of cerebral dissections or for the best treatment. We present 26 case studies derived from 70 pediatric patients affected by dissections, occlusions, and pseudoaneurysms.

The impact of temporary artery occlusion during intracranial aneurysm surgery on long-term clinical outcome: part I. Patients with subarachnoid hemorrhage.

BACKGROUND Temporary artery occlusion (TAO) during intracranial aneurysm surgery is an integral element in facilitating aneurysm dissection and clipping. Despite its significance, knowledge of effects of TAO on long-term clinical outcome is limited. The purpose of this study was to evaluate the impact of TAO in patients with subarachnoid hemorrhage (SAH) at one institution. METHODS Patients managed for an intracranial aneurysm were followed from January 2000 to July 2009. This study included a cohort of patients with a diagnosis of SAH who underwent TAO during aneurysm surgery. Risk factors known to affect outcome were considered. Effects of TAO time on long-term clinical outcome were evaluated using the Glasgow Outcome Scale (GOS) at last follow-up visit or hospital discharge. Analyses included descriptive statistics and binary logistic and ordinal logistic regression. RESULTS Inclusion criteria were met by 382 patients (74.3% female, age 52 years ± 13.5) with aneurysmal SAH. Mean follow-up was 39 months ± 57.3. Mean TAO time was 19.4 minutes ± 15.7. Of patients, 66% had a good outcome and made a complete recovery at last follow-up (GOS 5); 13% of patients were moderately disabled (GOS 4); and 27% of patients were severely disabled (GOS 3), were in a vegetative state (GOS 2), or had died (GOS 1). Overall, TAO time had no effect on overall long-term clinical outcome (P = 0.76). Higher Hunt and Hess grades (P < 0.001), Fisher computed tomography grades (P < 0.001), age (P < 0.001), larger size of aneurysm (P < 0.008), aneurysms of the posterior circulation (P = 0.044), and presence of clinical vasospasm (P < 0.001) were significantly associated with worse outcomes. On logistic regression analysis, the association between location of aneurysm (anterior vs. posterior circulation) and outcome disappeared. CONCLUSIONS Limited duration of TAO during aneurysm surgery did not affect long-term clinical outcome and appears to be safe in patients with aneurysmal SAH. Established SAH risk factors including Hunt and Hess grades, Fisher computed tomography grades, and presence of clinical vasospasm clearly correlated with long-term clinical outcomes.

Analysis of the uncinate processes of the cervical spine: an anatomical study.

OBJECT Although the uncovertebral region is neurosurgically relevant, relatively little is reported in the literature, specifically the neurosurgical literature, regarding its anatomy. Therefore, the present study aimed at further elucidation of this regions morphological features. METHODS Morphometry was performed on the uncinate processes of 40 adult human skeletons. Additionally, range of motion testing was performed, with special attention given to the uncinate processes. Finally, these excrescences were classified based on their encroachment on the adjacent intervertebral foramen. RESULTS The height of these processes was on average 4.8 mm, and there was an inverse relationship between height of the uncinate process and the size of the intervertebral foramen. Degeneration of the vertebral body (VB) did not correlate with whether the uncinate process effaced the intervertebral foramen. The taller uncinate processes tended to be located below C-3 vertebral levels, and their average anteroposterior length was 8 mm. The average thickness was found to be 4.9 mm for the base and 1.8 mm for the apex. There were no significant differences found between vertebral level and thickness of the uncinate process. Arthritic changes of the cervical VBs did not necessarily deform the uncinate processes. With axial rotation, the intervertebral discs were noted to be driven into the ipsilateral uncinate process. With lateral flexion, the ipsilateral uncinate processes aided the ipsilateral facet joints in maintaining the integrity of the ipsilateral intervertebral foramen. CONCLUSIONS A good appreciation for the anatomy of the uncinate processes is important to the neurosurgeon who operates on the spine. It is hoped that the data presented herein will decrease complications during surgical approaches to the cervical spine.

Enlarged parietal foramina: a review of genetics, prognosis, radiology, and treatment

IntroductionEnlarged parietal foramina are variable ossification defects in the parietal bones that present as symmetric radiolucencies on skull radiographs. In contrast to the normal small parietal foramina, enlarged parietal foramina are a hereditary condition and genes associated with it have been identified.MethodsA literature review was performed to discuss the many known findings related to enlarged parietal foramina.ConclusionsEven though they remain asymptomatic in the majority of cases, they may be associated with other pathologies and occasionally become symptomatic. This article provides a comprehensive review of the current knowledge of enlarged parietal foramina.

The Impact of Temporary Artery Occlusion During Intracranial Aneurysm Surgery on Long-Term Clinical Outcome: Part II. The Patient Who Undergoes Elective Clipping

BACKGROUND Temporary artery occlusion (TAO) during intracranial aneurysm surgery is a key element in facilitating aneurysm dissection and clipping. Despite its significance, knowledge of its effects on long-term clinical outcome in patients undergoing elective clipping for unruptured aneurysms is limited. This study evaluated the safety of this technique in this patient population by 1 surgeon. METHODS Patients managed for an intracranial aneurysm were followed from 2000-2009. This study included a cohort of patients found to have unruptured intracranial aneurysms who underwent TAO during their elective clipping procedure. Potential risk factors to affect outcome were considered. Effects of TAO on long-term clinical outcome were evaluated using the Glasgow Outcome Scale (GOS) obtained retrospectively by analyzing medical records at the last follow-up visit or discharge. Analyses included descriptive statistics, binary logistic regression, and ordinal logistic regression. RESULTS Inclusion criteria were met by 246 patients (75.2% female, age 54 years±10.9) with electively clipped, unruptured aneurysms. Mean follow-up was 53 months±67.5. Mean temporary artery clipping time was 16.1 minutes±14.7. Of patients, 86% had a good outcome and made a complete recovery at last follow-up (GOS 5); 9% of patients were moderately disabled (GOS 4); 5% of patients were severely disabled (GOS 3), were in a vegetative state (GOS 2), or had died (GOS 1). TAO time had no effects on overall long-term clinical outcomes (P=0.59). Although patients with posterior circulation aneurysms had a worse outcome compared with patients with anterior circulation aneurysms (P=0.008), age (P=0.176) and aneurysm size (P=0.497) were not significantly associated with clinical outcome. CONCLUSIONS This study did not demonstrate any relationship between limited duration of TAO and clinical outcome. Posterior circulation aneurysms are associated with worse long-term clinical outcomes in patients with electively clipped, unruptured aneurysms.

The pia mater: a comprehensive review of literature

IntroductionThe pia mater has received less attention in the literature compared to the dura and arachnoid maters. However, its presence as a direct covering of the nervous system and direct relation to the blood vessels gives it a special importance in neurosurgery.MethodA comprehensive review of the literature was conducted to study all that we could find relating to the pia mater, including history, macro- and microanatomy, embryology, and a full description of the related structures.ConclusionThe pia mater has an important anatomic position, rich history, complicated histology and embryology, and a significant contribution to a number of other structures that may stabilize and protect the nervous system.