Daryoush Tavanaiepour

Petrosal approaches to posterior circulation aneurysms.

Complex posterior circulation aneurysms are formidable lesions with an abysmal natural history. Their management continues to present a challenge to both endovascular and open microsurgical approaches. Affording an expansive, combined supra- and infratentorial exposure, the petrosal approaches are well suited for these challenging lesions when located along the basilar trunk or at a low-lying basilar apex. This report evaluates the evolution and application of petrosal approaches to these lesions. Excluding transsigmoid, infratentorial, or labyrinth-sacrificing approaches, the authors found 23 reports with 61 posterior circulation aneurysms treated via a petrosal approach. Although early morbidity was not negligible, rates of aneurysm occlusion (95% overall) and long-term outcome were quite laudable in light of the challenge posed by these lesions. Moreover, with accumulating experience with petrosal approaches, rates of complications are likely to wane, as neurosurgeons capitalize on the expansive exposure afforded by these indispensable approaches.

Evolution of the posterior petrosal approach

In this article, the authors review the history of the posterior petrosal approach. The early foundation of the retrolabyrinthine lateral petrosectomy has its roots in the otolaryngology literature. These early approaches were limited in exposure by the tentorium superiorly and the sigmoid sinus posteriorly. Although the concept of a transtentorial approach was originally combined with a complete labyrinthectomy, Hakuba and colleagues described the expansive exposure afforded by sectioning the tentorium and superior petrosal sinus and mobilizing a skeletonized sigmoid sinus. This maneuver serves as the key step in allowing for the full, combined supra- and infratentorial exposure that the posterior petrosal approach provides. In contrast to Hakuba et al.s approach, which used a partial labyrinthectomy, modern approaches often preserve the entire labyrinth (retrolabyrinthine approach). For added exposure, the latter can be combined with the anterior petrosal approach, allowing for the preservation of hearing and an enhanced view of the surgical target. The authors review the evolution of the petrosal approach and highlight its applicability.

Advances in Brain Tumor Surgery for Glioblastoma in Adults

Glioblastoma (GBM) is the most common primary intracranial neoplasia, and is characterized by its extremely poor prognosis. Despite maximum surgery, chemotherapy, and radiation, the histological heterogeneity of GBM makes total eradication impossible, due to residual cancer cells invading the parenchyma, which is not otherwise seen in radiographic images. Even with gross total resection, the heterogeneity and the dormant nature of brain tumor initiating cells allow for therapeutic evasion, contributing to its recurrence and malignant progression, and severely impacting survival. Visual delimitation of the tumor’s margins with common surgical techniques is a challenge faced by many surgeons. In an attempt to achieve optimal safe resection, advances in approaches allowing intraoperative analysis of cancer and non-cancer tissue have been developed and applied in humans resulting in improved outcomes. In addition, functional paradigms based on stimulation techniques to map the brain’s electrical activity have optimized glioma resection in eloquent areas such as the Broca’s, Wernike’s and perirolandic areas. In this review, we will elaborate on the current standard therapy for newly diagnosed and recurrent glioblastoma with a focus on surgical approaches. We will describe current technologies used for glioma resection, such as awake craniotomy, fluorescence guided surgery, laser interstitial thermal therapy and intraoperative mass spectrometry. Additionally, we will describe a newly developed tool that has shown promising results in preclinical experiments for brain cancer: optical coherence tomography.

Peripheral Neuromodulation for Treatment of Chronic Migraine Headache

Chronic migraines (CM) affect approximately 2% of the population, resulting in significant disability, economic burden, and impairments in quality of life. Historical neurosurgical procedures, such as lesioning of the trigeminal dorsal root entry zone or neurolysis of the occipital nerve, have not gained favor because of procedural morbidity and poor durability, respectively. Occipital nerve stimulation is emerging as a potentially promising modality for the treatment of CM, with greater than 50% pain reduction in approximately 80% of patients in open-label trials and ∼40% of patients in randomized controlled trials. Mechanisms of neuromodulation remain unclear.

Primary calcified rhabdoid meningioma of the cranio-cervical junction: A case report and review of literature

Rhabdoid meningioma (RM) is a relatively new, rare, and aggressive subtype of meningioma, classified as Grade III malignancy in 2000, 2007 versions of WHO classification of the central nervous system. We reviewed the data available from all published cases of RMs. To the best of our knowledge, there are more than 100 published cases of RMs; none have documented extensive calcification or origin from the cranio cervical junction. We report the first case of a totally calcified (stony mass), primary RM, at the cranio cervical junction. Also, we highlighted the role of the transcondylar approach to achieve microscopic total removal of such a challenging lesion. A 37 year old female, allergic to erythromycin, presented with 5 years of progressive right upper extremity numbness and weakness, right facial numbness, and occipital pain. Imaging demonstrated a large calcified mass at the right posterior–lateral margin of the cranio cervical junction, encasing the right vertebral artery and right PICA loop. Patient underwent microscopic total resection of the lesion. Pathological diagnosis was confirmed as RM with atypical features. Subsequently, the patient received postoperative intensity modulated radiotherapy (IMRT) on the tumor bed, and close follow up imaging showed no recurrence 2 years after surgery. We report the first case of a primary RM originating from the cranial cervical junction; also, it is the first case to present with extensive calcification in this morphological subtype. We also conclude that RM has now become a feature of newly diagnosed cases and not only a disease of recurrent cases as it was thought in the past. Since RMs are typically considered aggressive, total surgical resection with close follow up and postoperative adjuvant radiation should be considered. However, the adjuvant therapy of each separate case of RM should be tailored according to its particular histopathologic profile.

Paradoxical Distraction with Upright Position After Halo Fixation in 2 Patients with Atlanto-Occipital Dislocation

BACKGROUND Atlanto-occipital dislocation (AOD) is the most uncommon form of traumatic cervical spine injury. The majority of patients die before reaching higher-level care, and only a small percentage of patients with AOD survive the initial injury after receiving tertiary care. As such, there is a paucity of evidence-based management guidelines for treating this condition. Halo vest fixation has been a proposed method for interim stability while these patients undergo medical optimization for surgical intervention. There have been several reports of worsening AOD after halo placement. Reverse Trendelenburg position after halo fixation has been previously described to aid in the reduction of AOD, as well as concomitant atlantoaxial dislocation by gravitational downward force. CASE DESCRIPTION In this series we present 2 cases of obese patients (body mass index >30) with AOD treated by halo fixation that had increased distraction after head of bed elevation. CONCLUSION Our theorized mechanism for this phenomenon is due to the downward pull of subaxial forces secondary to a large body habitus.

Surgically Treated de Novo Cervicomedullary Arachnoid Cyst in Symptomatic Adult Patient

BACKGROUND Arachnoid cysts are a relatively common finding in adult patients, especially with the advent of advanced imaging techniques. The overall incidence ranges from 1%-2%, and the majority are clinically silent. Arachnoid cysts are postulated to arise by congenital anomalies or trauma. De novo formation of arachnoid cysts has been reported but is exceptionally rare and mostly found in the pediatric population after head trauma. There have only been 2 reported cases of symptomatic de novo arachnoid cyst formation in adult patients to date, both with histories of head trauma. CASE DESCRIPTION We present a case of a 71-year-old male patient with progressive vertigo who had previous brain magnetic resonance imaging studies without abnormalities. Another MRI was performed 3 years from the last study that showed interval development of a large cystic lesion compressing the right cervicomedullary junction, as well as radiologic evidence of neurosarcoidosis. Intraoperative findings showed a cystic mass with clear, gelatinous fluid. The cyst was drained, and the walls were resected and sent to pathology. Histopathologic testing confirmed the lesion was an arachnoid cyst. The patients vertiginous symptoms improved after surgery. CONCLUSIONS This case represents the first incidence of a pathology-proven, nontraumatic de novo arachnoid cyst.

Surgical Management of Spontaneous and Traumatic Anterior Skull Base Meningoceles: Technique and Pitfalls

Objectives: A majority of anterior skull base meningoceles are often managed via the endoscopic endonasal approach (EEA) for the excision and repair of the cerebrospinal fluid (CSF) leak, in addition to the reconstruction of the skull base defect. The aim of the study was evaluation of an institutional case series to identify specific risks and strategies for successful management of anterior skull base meningoceles. Methods: Case series review of all surgical cases involving repair of any anterior skull base meningocele spanning 3 years. Results: A total of 18 patients were managed surgically for repair of meningocele with or without CSF rhinorrhea. All patients had postoperative follow-up to one year. EEA was used in 17 patients, and one had a combined transcranial with endoscopic approach. Four patients had meningoceles with a larger than 1.0-cm bony skull base defect. Large spontaneous meningoceles along the ethmoid were likely to include cerebrovascular structures within their intranasal component. Nasal airway obstruction was the initial presenting symptom in all large spontaneous ethmoid meningoceles, rather than CSF rhinorrhea (present in all large traumatic ones). Conclusions: The endoscopic technique is a safe and effective approach to repair of anterior skull base defects involving both ethmoid and sphenoid regions. Successful repair of lateral sphenoid wall defects depends on gaining sufficient access via incorporating extended approaches, such as trans-pterygopalatine approach. Preoperative angiography may be warranted, especially in spontaneously appearing anterior skull base meningoceles with a bony defect larger than 1.0 cm.