Rami James N. Aoun

Microsurgical Treatment of Previously Coiled Intracranial Aneurysms: Systematic Review of the Literature

OBJECTIVE To assess indications, complications, clinical outcomes, and technical nuances of microsurgical treatment of previously coiled intracranial aneurysms. METHODS A systematic review of the literature was performed using PubMed/MEDLINE and EMBASE databases from January 1990 to December 2013. English-language articles reporting on microsurgical treatment of previously coiled intracranial aneurysms were included. Articles that involved embolization materials other than coils were excluded. Data on aneurysm characteristics, indications for surgery, techniques, complications, angiographic obliteration rates, and clinical outcomes were collected. RESULTS The literature review identified 29 articles reporting on microsurgical clipping of 375 previously coiled aneurysms. Of the aneurysms, 68% were small (<10 mm). Indications for clipping included the presence of a neck remnant (48%) and new aneurysmal growth (45%). Rebleeding before clipping was reported in 6% of cases. Coil extraction was performed in 13% of cases. The median time from initial coiling to clipping was 7 months. The angiographic cure rate was 93%, with morbidity and mortality of 9.8% and 3.6%, respectively. CONCLUSIONS Microsurgical clipping of previously coiled aneurysms can result in high obliteration rates with relatively low morbidity and mortality in select cases. Considerations for microsurgical strategies include the presence of sufficient aneurysmal tissue for clip placement and the potential need for temporary occlusion or flow arrest. Coil extraction is not needed in most cases.

Futuristic Three-Dimensional Printing and Personalized Neurosurgery

Figure 1. Continuous liquid interface production apparatus. From Tumbleston JR, Shirvanyants D, Ermoshkin N, Janusziewicz R, Johnson AR, Kelly D, Chen K, Pinschmidt R, Rolland JP, Ermoshkin A, Samulski ET, DeSimone JM: Additive manufacturing. Continuous liquid interface production of 3D objects. Science 347:1349-1352, 2015. Reprinted with permission from AAAS. Disruptive technologies are rare phenomena. However, when they do come about, they have the potential to change the course of entire industries. Such is the case with the new three-dimensional (3D) printing technology from Carbon3D Inc. (Redwood City, California, USA), dubbed Continuous Liquid Interface Production (CLIP). With its innovative approach to additive manufacturing, CLIP has the potential to usurp and revolutionize 3D printing, with reverberations into several fields, including neurologic surgery. Conventional additive manufacturing, like Polyjet, Fused Deposition Modeling (FDM), Stereolithography (SLA) and Laser Sintering technology (SLS), function by adding materials layer by layer. For these techniques, two-dimensional printing is repeated over and over again until a 3D physical rendering is produced. Consequently, such a process takes several hours and in most cases results in an unfinished and “pixelated-like” end product. A post-processing interval adds further time to the process. CLIP technology, as described by Tumbleston et al., prints 3D physical models in a continuous fashion as opposed to layer by layer in conventional machines. This approach capitalizes on 2 opposing forces: ultraviolet (UV) light that promotes polymerization of resin, in contrast to oxygen (O2), which inhibits the polymerization of resin. The apparatus itself consists of a bath filled with resin, an O2-permeable and UVpermeable membrane, a build support plate, and a UV imaging unit (Figure 1). Polymerization of the intended part begins when a continuous sequence of UV images is projected through the O2permeable, UV-transparent window below the resin bath; this creates a layering, whereby directly above the window a liquid dead zone rich in O2 exists, where no polymerization occurs. Directly above the dead zone, O2 concentration decreases, and polymerization of the resin and construction of the 3D model occur, guided by the projected UV images. Simultaneously, the 3D part is elevated out of the resin bath by a continuously elevating build support plate (Video I). This process can speed up 3D printing up to 100-fold, producing a high-resolution finished or near-finished product without the layerings of 3D printing. A job that used to take hours now takes only minutes to complete. Moreover, the spectrum of

Minimally Invasive Tubular Resection of Lumbar Synovial Cysts: Report of 40 Consecutive Cases.

BACKGROUND Lumbar synovial cysts are a relatively common clinical finding. Surgical treatment of symptomatic synovial cysts includes computed tomography-guided aspiration, open resection and minimally invasive tubular resection. We report our series of 40 consecutive minimally invasive microscopic tubular lumbar synovial cyst resections. METHODS Following Institutional Review Board approval, a retrospective analysis of 40 cases of minimally invasive microscopic tubular retractor synovial cyst resections at a single institution by a single surgeon (B.D.B.) was conducted. Gross total resection was performed in all cases. RESULTS Patient characteristics, surgical operating time, complications, and outcomes were analyzed. Lumbar radiculopathy was the presenting symptoms in all but 1 patient, who presented with neurogenic claudication. The mean duration of symptoms was 6.5 months (range, 1-25 months), mean operating time was 58 minutes (range, 25-110 minutes), and mean blood loss was 20 mL (range, 5-50 mL). Seven patients required overnight observation. The median length of stay in the remaining 33 patients was 4 hours. There were 2 cerebrospinal fluid leaks repaired directly without sequelae. The mean follow-up duration was 80.7 months. Outcomes were good or excellent in 37 of the 40 patients, fair in 1 patient, and poor in 2 patients. CONCLUSIONS Minimally invasive microscopic tubular retractor resection of lumbar synovial cysts can be done safely and with comparable outcomes and complication rates as open procedures with potentially reduced operative time, length of stay, and healthcare costs. Patient selection for microscopic tubular synovial cyst resection is based in part on the anatomy of the spine and synovial cyst and is critical when recommending minimally invasive vs. open resection to patients.

Use of a harvested radial artery graft with preservation of the vena comitantes to reduce spasm risk and improve graft patency for extracranial to intracranial bypass: Technical note

BACKGROUND AND SIGNIFICANCE The vessels of choice for cerebrovascular high-flow direct bypass procedures are the radial artery and the saphenous vein. Radial artery grafts have become favored over saphenous vein grafts because of higher patency rates and better size matching to appropriate recipient vessels. Radial grafts are prone to spasm however, and this may be seen in 4-10% of cases and can be associated with ischemic sequelae. The standard technique for radial artery harvest calls for complete separation of the artery from its adventitial attachments and associated venous network. There is reason to believe that this could contribute to spasm risk and possibly even thrombosis. Radial graft outcomes appear to be improved when the vena comitantes is preserved in cardiac and peripheral applications. We report the novel use of a harvested radial artery graft with preservation of its venae comitantes for extracranial to intracranial bypass. CLINICAL PRESENTATION The patient is a 59-year-old male who had a blunt head trauma with associated loss of consciousness and who was led to the incidental discovery of a large fusiform middle cerebral artery (MCA) aneurysm. CONCLUSION Preservation of the vena comitantes when harvesting a radial arterial graft for bypass, along with dual (arterial and venous) anastomoses, and concomitant use of intra-operative vaso-dilatory maneuvers to prevent spasm, may improve overall graft patency and patient outcome.

Hypothermia not Supported as a Therapeutic Option for Traumatic Brain Injury in Recent Randomized Trial

Traumatic brain injury (TBI) is a leading cause of permanent disability in people younger than 40 years of age. An increase in intracranial pressure (ICP) during hospitalization for a TBI has been associated with poor long-term neurologic outcomes. On the basis of encouraging research, hypothermia has been embraced by some centers as an innovative way to treat high ICP. More recent trials, however, have hinted that therapeutic hypothermia might contribute to poor neurologic outcomes. In an attempt to define the role of hypothermia in TBI, the Eurotherm 3235 Trial collaborators conducted a randomized controlled trial, which was published October 7, 2015 in the New England Journal of Medicine. The inclusion criteria included patients with closed head injury who sustained an ICP >20 mm Hg for >5 minutes. For the purpose of creating a framework for study analysis, treatments for TBI were divided into stage 1, 2, and 3 therapies (Table 1). Eligible patients were randomized to an experimental arm, hypothermia (32 C 35 C) in addition to best management practice, and a control arm that consisted of best management practices alone. Statistical analysis was performed using ordinal logistic regression to compare the Extended Glasgow Outcome Scale scores between the hypothermia and control groups at 6 months. Only 25.7% of patients from the hypothermia group (49/191) had favorable outcomes at

Defining the Immune Phenotype for Glioblastoma Multiforme: One Step Closer to Understanding Our Enemy.

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Synthetic Replica for Training in Microsurgical Anastomosis: An Important Frontier in Neurosurgical Education

Medical education has evolved through the years, moving away from the Halstedian apprenticeship model. The medical governing bodies involved in medical graduate education have established a set of rulings and recommendations focused on improving patient safety and curbing resident fatigue including limiting work hours to 80 h a week. In addition to duty hour regulations, decreasing volumes and dilution of surgical cases among an increasing number of tertiary care centers have raised concern about the ability of residents to achieve appropriate levels of competency by the time of graduation. Therefore, simulation has seen an increased role in education in the last decade.

Complication Avoidance and Management Research

Complication avoidance is a major consideration with any surgical procedure, and evaluation of complications relies on clear definitions. However, defining what constitutes a complication can be difficult, as perspectives on errors of commission or omission often vary between providers and patients. Here, we present a concise analysis of complications related to neurovascular surgery (defined as any procedural care of patients with neurovascular diseases) and provide a framework for approaching research efforts. This is done by considering opportunities in disease screening and patient selection, perioperative morbidity reduction, and follow-up. In addition, the concept of complication avoidance through surgical simulation is briefly dealt with. This chapter is intended to serve as an initial reference point for the young neurovascular specialist for developing and elaborating on the concept of complication avoidance through various techniques of research.

Bioresorbable Intracranial Sensors: A New Frontier for Neurosurgeons

The management of brain, spinal cord, and peripheral nerve disorders and injury may benefit from more robust continuous monitoring. Implantation of biosensors is limited by the risk of infection and the need for a second procedure to extract the sensor. Bioresorbable sensors are electronic sensors that can run the required functional course in the body but eliminate via absorption over a reasonable period of time. If properly designed, bioresorbable sensors promise to overcome the limitations of current sensors and reduce the threshold for continuous monitoring.

Managing Post-tPA Intracranial Hemorrhage: Time Is Still Brain

Symptomatic intracerebral hemorrhage (sICH) is the most dreaded complication in ischemic stroke patients treated with recombinant tissue plasminogen activator (rtPA). Symptomatic intracerebral hemorrhage is associated with significant morbidity and a mortality rate of approximately 50%. Yet management of this cohort has been based mostly on anecdotal experience. Since its approval by the U.S. Food and Drug Administration in 1996, rtPA has become the standard of care for select patients with acute ischemic stroke. In the October JAMA Neurology issue, Yaghi et al. reported on a retrospective study examining current treatment paradigms for sICH after rtPA administration at 10 U.S. stroke centers. Patients included in the study had to meet the criteria for the Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST). Symptomatic intracerebral hemorrhage was defined as the presence of a parenchymal hematoma accounting for more than one third of the infarct volume (parenchymal hematoma type 2) identified on head computed tomography (CT) with at least a 4point increase from the baseline National Institute of Health Stroke Scale (NIHSS). The primary outcome was in-hospital mortality, and the secondary outcome was hematoma expansion identified on follow-up CT. Other variables were included in the study to examine if there was any association between in-hospital mortality and hematoma expansion. First data on pretreatment factors were reported. These factors included patient demographics, stroke risk factors, antiplatelet or anticoagulant use before thrombolysis, admission NIHSS, and code status change to comfort care measures. Second were laboratory measures, comprising pretreatment blood glucose level, coagulation laboratory values, and fibrinogen level. Third were imaging features including hematoma volume and the time from initiation of rtPA therapy to sICH diagnosis. Fourth was the treatment modality, ranging from fresh frozen plasma, cryoprecipitate, vitamin K, platelet transfusion, recombinant factor VIIa, aminocaproic acid, and surgical decompressive craniotomy or hematoma evacuation.