Shear stress and aneurysms: a review.

Wall shear stress, the frictional force of blood flow tangential to an artery lumen, has been demonstrated in multiple studies to influence aneurysm formation and risk of rupture. In this article, the authors review the ways in which shear stress may influence aneurysm growth and rupture through changes in the vessel wall endothelial cells, smooth-muscle cells, and surrounding adventitia, and they discuss shear stress-induced pathways through which these changes occur.

Growing up with spina bifida: bridging the gaps in the transition of care from childhood to adulthood.

Spina bifida is the most common nonchromosomal birth defect, resulting in permanent disability of multiple organ systems, yet compatible with long-term survival. Important advances across various disciplines have now improved survival among the spina bifida population. Although the majority of individuals living with spina bifida are now adults, there are few publications in the neurosurgical literature regarding the care of adults with spina bifida, associated medical conditions, surgical interventions, and long-term complications. The major goals for transitioning adult patients with spina bifida are preservation of function and promotion of independence as well as general overall health. Nevertheless, many gaps exist in our knowledge and understanding of the complex needs of this aging patient population. The goal of this paper was to provide a comprehensive updated review of the literature regarding the challenges and considerations involved in the transitional care to adulthood for patients with spina bifida. Unique to this review, the authors provide a first-hand personal communication and interview with an adult patient with spina bifida that discusses many of these challenges with transition.

Surgical Closure of the Eustachian Tube Through Middle Fossa and Transmastoid Approaches: A Pilot Cadaveric Anatomy Study.

BACKGROUND: Cerebrospinal fluid rhinorrhea after temporal bone surgery involves drainage from the Eustachian tube (ET) into the nasopharynx, causing significant patient morbidity. Variable anatomy of the ET accounts for failures of currently used ET obliteration techniques. OBJECTIVE: To describe the surgical anatomy of the ET and examine possible techniques for ET closure through middle fossa (MF) and transmastoid approaches. METHODS: We described the surgical anatomy of the ET from the MF and transmastoid approaches in 5 adult cadaveric heads, measuring morphometric and surgical anatomy parameters and establishing targets for definite ET obliteration. RESULTS: The osseous ET measured an average of 19.53 mm (±1.56 mm), with a mean diameter of 2.24 mm (±0.29 mm). The shortest distance between the greater superficial petrosal nerve and the ET junction was 6.61 mm (±0.61 mm). Shortest distances between the ET junction and the foramen spinosum and posterior border of the foramen ovale were 1.09 mm (±0.24 mm) and 2.03 mm (±0.30 mm), respectively. Closure of the cartilaginous ET may be performed by folding it in on itself, securing it by packing, suturing, or surgical clip ligation. CONCLUSION: Definite obliteration of the cartilaginous ET appears feasible and the most definite approach to eliminate egress of cerebrospinal fluid to the nasopharynx using the MF approach. This technique may be used as an adjunct to skull base procedures where ET closure is planned.

A Rational Approach to the Management of Cerebral Arteriovenous Malformations.

OBJECTIVE: Cerebral arteriovenous malformations (AVMs) typify the delicate balance cerebrovascular specialists face in weighing the treatment risk against the natural history of a pathologic lesion. The goal of our review was to provide an overview of the current evidence for the treatment of cerebral AVMs and describe a contemporary approach to developing a treatment strategy according to individual AVM characteristics. METHODS: A review of the contemporary literature on the natural history and treatment of cerebral AVMs was completed through the PubMed and Google Scholar databases. The studies were reviewed for original advances in the characterization and treatment of cerebral AVMs. RESULTS: The overall risk of hemorrhage for cerebral AVMs is 2%-4% per year. Individual AVM characteristics, including small size, exclusive deep venous drainage, deep or posterior fossa location, venous ectasia, and the presence of a flow-associated aneurysm, appear to confer a greater risk of presentation with rupture. A diverse array of modalities have been developed to achieve the goal of complete lesion obliteration, including microsurgery, endovascular therapy, and radiosurgery. Advances in treatment strategies and technology have continued to decrease the morbidity associated with lesion obliteration. CONCLUSIONS: Microsurgical or multimodal treatment strategies are often required to achieve complete obliteration; however, it remains critical that each treatment approach is individualized by the specific AVM characteristics.

Sensitivity and Specificity of Intraoperative Neuromonitoring for Identifying Safety and Duration of Temporary Aneurysm Clipping Based on Vascular Territory, a Multimodal Strategy.

BACKGROUND: Patients who undergo clipping of cerebral aneurysms face an inherent risk for new postoperative neurologic deficits. Intraoperative neuromonitoring (IONM) is used often for early detection of ischemic changes, while it is still potentially reversible. However, the value, safety, and efficacy of temporary clipping and multimodal IONM to minimize risks are debated. Our retrospective series examined the sensitivity and specificity of IONM using transcranial motor evoked potentials and somatosensory evoked potentials and quantified the safety of temporary clipping by duration and vascular territory. METHODS: Our prospectively collected database (2010-2013) included 123 consecutive patients who underwent clipping of 133 cerebral aneurysms with use of IONM. We determined postoperative deficit rate and sensitivity and specificity of monitoring to predict these changes intraoperatively. The rate of permanent deficit after temporary clipping was correlated with duration, vascular territory, and IONM findings. RESULTS: Of 133 clipped aneurysms, 15 instances of IONM changes occurred, including 12 temporary without new postoperative deficit and 3 permanent with new postoperative deficit. Somatosensory evoked potential monitoring predicted one of the permanent deficits and transcranial motor evoked potentials predicted the other 2 deficits. CONCLUSIONS: Multimodal IONM was highly specific and sensitive for detecting new deficits. Three patients with new deficits had temporary clipping, including 2 patients with IONM changes not temporally associated with clip placement. Our 1.1% rate of permanent neurologic deficit attributed to temporary clipping support its safety. Differences in patterns of IONM changes among vascular territories warrant further investigation.