Somatic Variants in SVIL in Cerebral Aneurysms.

Background and Objectives: While somatic mutations have been well-studied in cancer, their roles in other complex traits are much less understood. Our goal is to identify somatic variants that may contribute to the formation of saccular cerebral aneurysms. Methods: We performed whole-exome sequencing on aneurysm tissues and paired peripheral blood. RNA sequencing and the CRISPR/Cas9 system were then used to perform functional validation of our results. Results: Somatic variants involved in supervillin (SVIL) or its regulation were found in 17% of aneurysm tissues. In the presence of a mutation in the SVIL gene, the expression level of SVIL was downregulated in the aneurysm tissue compared with normal control vessels. Downstream signaling pathways that were induced by knockdown of SVIL via the CRISPR/Cas9 system in vascular smooth muscle cells (vSMCs) were determined by evaluating changes in gene expression and protein kinase phosphorylation. We found that SVIL regulated the phenotypic modulation of vSMCs to the synthetic phenotype via Krüppel-like factor 4 and platelet-derived growth factor and affected cell migration of vSMCs via the RhoA/ROCK pathway. Discussion: We propose that somatic variants form a novel mechanism for the development of cerebral aneurysms. Specifically, somatic variants in SVIL result in the phenotypic modulation of vSMCs, which increases the susceptibility to aneurysm formation. This finding suggests a new avenue for the therapeutic intervention and prevention of cerebral aneurysms.

Diffusion Tensor Imaging and Tractography Utilized in the Resection of a Midbrain Cavernous Malformation.

Background: Diffusion tensor imaging (DTI) is a magnetic resonance-based imaging technique that can provide important information about the underlying structure and integrity of the white matter in the brain. Tractography, a DTI postprocessing technique, can provide a detailed model of individual white matter fiber tracts. Knowledge of these tracts may be beneficial in the surgical planning and execution for neurosurgical patients. Case Report: We review the basic principles behind DTI and present an illustrative case in which DTI was used to delineate the relationship of eloquent white matter tracts to a cavernous malformation in a patient undergoing resection. Conclusion: The use of DTI during preoperative planning allows the neurosurgeon to understand if a lesion is disrupting, infiltrating, or altering the course of local white matter tracts. With the combined use of DTI and intraoperative neuronavigation, the neurosurgeon can better identify and avoid white matter tracts, not only in the local area of resection but also during approach to the lesion, thereby reducing the risk of damage to vital cortical pathways and subsequent functional impairment.

Interhemispheric Paracallosal Approach for an Arteriovenous Malformation of the Atrium: A Novel Technique.

Background: Intraventricular lesions present a surgical challenge because of the complexity of the ventricular anatomy, various perforating arteries, and eloquent brain areas surrounding the system. The ventricular atrium is particularly challenging because of the cingulate gyrus, corpus callosum, optic pathways, and significant vascular structures. We present the case of a patient for whom we used a new surgical approach to reach a lesion in the ventricular atrium. Case Report: A 26-year-old male presented with an intraventricular hemorrhage, acute hydrocephalus, and a grade III arteriovenous malformation (AVM) in the atrium of the left lateral ventricle. We approached the AVM through a posterior parietooccipital paracallosal interhemispheric approach. Instead of transecting the cingulate cortex as is traditionally done, we gently retracted the cingulate gyrus and made a small paracallosal incision to reach the atrium of the left lateral ventricle. The surgery was uneventful. The patient recovered well and was discharged home on postoperative day 3 without any deficits. Conclusion: This case illustrates a novel variation to an established approach to the ventricular atrium. With this technique, the surgeon minimizes disruption of brain tissue and thereby avoids the associated postoperative deficits associated with traditional approaches (transcortical, transcingulate, and conventional transcallosal). Tractography studies and a large cohort of patients are necessary to ensure the reproduction of good outcomes.

Carotid Web Stenting.

Background: Carotid webs are luminal, shelf-like protrusions at the carotid bulb. Considered to be a variant of fibromuscular dysplasia, carotid webs have been observed principally in African American females. The association between carotid webs and recurrent ischemic strokes continues to be established as patients without traditional stroke risk factors are found to have carotid webs as the only possible cause of symptomatic deficits. The majority of patients undergo endarterectomy; few stent placements are reported. We present the case of an African American female who underwent stent placement for treatment and secondary prevention of stroke attributed to a carotid web. Case Report: A 33-year-old African American female presented with acute onset left hemiparesis and left facial droop. Alteplase was administered; multiphase head and neck computed tomography angiography revealed an occlusion of the right middle cerebral artery with a web at the carotid bulb. Aspiration catheter thrombectomy achieved a Thrombolysis in Cerebral Infarction (TICI) score of 3. She was placed on 2 antiplatelet agents, and 3 weeks later she underwent stent placement. Follow-up digital subtraction angiography at 3 months showed obliteration of the right carotid artery web and satisfactory integration of the stent into the vessel wall. She was reassessed at 1 year and reported no neurologic symptoms. Conclusion: Although carotid webs are most commonly treated with endarterectomy, they may be amenable to stent therapy with favorable clinical outcomes as shown with this patient.

Midline minimally invasive placement of spinal cord stimulators: a technical note.

BACKGROUND: Spinal cord stimulators (SCSs) have conventionally been implanted through open approaches requiring extensive muscle dissection to perform laminectomies and permanently place the paddle lead. This approach could contribute to worsening the pain syndrome in patients who experience chronic pain. In an attempt to reduce operative times, minimize blood loss and postoperative pain, and ease the technical challenges of placing the paddle lead in the midline via a paramedian and off-midline incision, we designed a new minimally invasive surgery (MIS) technique to place the paddle lead using a tubular retractor system through a true midline approach. METHODS: We performed a retrospective review of all MIS paddle lead placements performed by the senior author between October 2010 and June 2013. Patient demographics; clinical indications for placement of paddle lead; location of paddle lead; and perioperative data including blood loss, length of surgery, and surgical and perioperative morbidity were recorded. RESULTS: Between October 2010 and June 2013, 78 patients had MIS placement of paddle lead SCSs. Patient ages ranged from 27 to 87 years old, with a mean age of 59. The most common levels for paddle lead placement were T8 and T9. No minor or major neurologic complications occurred in our patient population. No patient was readmitted after being discharged from the hospital and all surgeries were outpatient procedures. We had a migration rate comparable to open techniques and minimal blood loss. CONCLUSION: Our technique is safe and effective and carries minimal surgical morbidity compared to standard open techniques for placement of SCSs.

Intraoperative neurophysiological monitoring for minimally invasive 1- and 2-level transforaminal lumbar interbody fusion: does it improve patient outcome?

BACKGROUND: Despite the widespread use of intraoperative monitoring (IOM) in many types of spinal surgeries, an absence of data comparing monitored a nd unmonitored postoperative outcomes places IOM's efficacy into question. A lack of consensus among surgeons about when to use monitoring also raises concerns about its overuse in routine and low-risk procedures. METHODS: We performed a retrospective database review of 112 patients undergoing a 1- or 2-level minimally invasive surgery transforaminal lumbar interbody fusion (MIS-TLIF). Our analysis focused on patient demographics, use of IOM, length of surgery, hospital length of stay, the perioperative complication of pedicle screw malposition, and average hospital cost. RESULTS: For the 73 patients who underwent MIS-TLIF with intraoperative neuromonitoring, their hospital length of stay (P=0.8) and need for pedicle screw revisions (P=0.93) were not statistically significant compared to the 39 patients who underwent MIS-TLIF procedures without IOM. The incidence of reoperation was 5.48% and 5.13%, and average length of stay was 3.25 days and 3.13 days, respectively. However, the cost of surgery and the length of surgery were significantly higher in the monitored group compared to the nonmonitored group (P=0.008 and P=0.009, respectively). CONCLUSION: IOM is widely used in spine surgery, but our retrospective review shows that its use does not necessarily decrease the incidence of malpositioning of pedicle screws. In fact, no statistical difference was detected in the incidence of screw malposition in the 2 groups of patients. On the other hand, IOM adds cost and increases the length of surgery. Because the use of IOM did not make a difference in the incidence of pedicle screw malpositioning and because of the comparative cost analysis for both groups of patients, we believe that the use of IOM for MIS-TLIF provides no added benefit.

Fetal surgery: the ochsner experience with in utero spina bifida repair.

BACKGROUND: Myelomeningocele is the most common form of congenital central nervous system defect that is compatible with life. Most patients with myelomeningocele have significant functional impairment of ambulation and bowel and bladder function, require permanent cerebrospinal fluid diversion with shunting, and have significant morbidity and mortality from hindbrain herniation (Chiari II malformation). The advent of intrauterine surgery has provided new opportunities to better address this lifelong debilitating disease. CASE REPORT: The patient was a 19-year-old gravida 2 para 1 at 22-6/7 weeks whose fetus was diagnosed with an open neural tube defect and further demonstrated to have ventriculomegaly and hindbrain herniation. Amniocentesis confirmed normal karyotype and the presence of acetylcholinesterase. After an intrauterine procedure, the patient underwent cesarean section at 35-5/7 weeks and delivered a male infant. His spinal incision was well healed at birth without any evidence of cerebrospinal fluid leakage, and his extremities were normal in appearance, range of motion, and movement. The infant also has maintained relatively normal, age-appropriate bowel and bladder function and has no obvious neurologic deficit. CONCLUSION: As the benefit of fetal surgery becomes more widely accepted, quality of care and patient safety must be at the forefront of any institution's effort to offer fetal surgery. Given the current prevalence of spina bifida and the amount of resources required to treat this disease effectively either in utero or postnatally, it is our opinion that the treatment of spina bifida should be regionalized to tertiary referral centers with the interdisciplinary expertise to offer comprehensive treatment for all aspects of the disease and all phases of care for the patients.

One-stage resection of giant invasive thoracic schwannoma: case report and review of literature.

BACKGROUND: Schwannomas comprise approximately 25% of all spinal tumors, being the third most frequent soft-tissue tumor after hemangiomas and lipomas. Grade 5 invasive giant schwannomas erode the vertebral bodies, involve 2 or more levels, and invade the myofascial planes. Because 3 compartments are involved, these tumors represent a surgical challenge and frequently require staged surgeries with a multidisciplinary surgical team. CASE REPORT: We report the case of a 62-year-old female who presented with intermittent upper back pain for 3 years. A magnetic resonance imaging scan of the thoracic spine showed a mass invading the vertebral body, pedicle, and lamina of T4 and part of T3 and T5. Needle biopsy confirmed the diagnosis of schwannoma. The patient underwent surgery using a parascapular extracavitary costotransversectomy approach. CONCLUSION: Giant invasive spinal schwannomas are rare in the thoracic spine, and surgical approaches usually have entailed multiple-stage surgeries with the assistance of other surgical specialties. Our 1-stage complete surgical resection of a giant invasive spinal schwannoma used a parascapular costotransversectomy approach that maintained spinal stability and thus avoided the need for instrumentation.