Vascularized Rib Bone Grafting: Indications, Techniques, and Clinical Outcomes.

Pseudarthrosis is a difficult complication often seen in patients with complex spinal pathology. To supplement existing neurosurgical approaches to cervicothoracic spinal instrumentation and fusion, novel vascularized rib bone grafts can be utilized in patients at high risk for failed spinal fusion. In this article, we discuss the indications, benefits, surgical technique, feasibility, and limitations of using rib vascularized rib bone grafts to augment spinal fusion.

Techniques of Onyx Embolization of Arteriovenous Malformation: 2-Dimensional Operative Video.

Advances in endovascular techniques and tools have allowed for treatment of complex arteriovenous malformations (AVMs), which historically may have posed unacceptable risk for open surgical resection. Endovascular treatment may be employed as an adjunct to surgical resection or as definitive therapy. Improvements in embolization materials have made endovascular AVM treatment safer for patients and useful across a variety of lesions. While many techniques are employed for transarterial AVM embolization, the essential tenets apply to all procedures: (1) great care should be taken to cannulate only vessels directly supplying the lesion, and not en passage vessels, prior to injecting embolisate; (2) embolisate should travel into the nidus, but not into the draining veins; (3) embolistate reflux proximal to the microcatheter should be avoided. There are several techniques that accomplish these goals, including the plug and push method, or using a balloon to prevent embolisate reflux. We use controlled injection of liquid Onyx (Medtronic), with increasing pressure over multiple injections pushing the embolisate forward into the AVM. This is repeated in multiple feeding vessels to decrease or eliminate supply to the AVM. Here, we present a 36-yr-old female with a right parietal AVM discovered on workup of headaches. After informed consent was obtained, she underwent preoperative embolization using this technique prior to uncomplicated surgical resection. The video shows the endovascular Onyx embolization of multiple feeding vessels over staged treatment.

Vascularized Bone Grafts for Spinal Fusion-Part 2: The Rib.

BACKGROUND: Pseudoarthrosis, or failure to achieve bony union, is a well-known complication of spinal fusion operations. Rates range from 5% to 40% and are influenced by both patient and technical factors. Patients who do not achieve complete fusion may experience a return or worsening of their preoperative pain. For patients with complicated pathologies, vascularized bone grafts (VBGs) have been shown to provide better outcomes than nonvascularized bone grafts (N-VBGs). OBJECTIVE: To enhance an instrumented spinal fusion by the innovative technique presented herein that utilizes a rotated, pedicled VBG from the left eighth rib under the paraspinous musculature into the midlumbar posterolateral gutter. METHODS: For posterior approaches, the rib can be easily accessed and rotated into the appropriate strut position. The rib is dissected out, identifying and preserving the neurovascular bundle medially. The rib is then tunneled medially and appropriately positioned as the spinal graft, with the curve providing anatomic kyphosis or lordosis, depending on the surgical location. It is then successfully fixated with plates and spinal screws. RESULTS: In our limited experience to date, vascularized rib grafting procedures augment fusion and reduce operating room time and bleeding compared to free flap procedures. No patients have experienced complications related to these grafts. CONCLUSION: Pedicled vascularized rib grafts can be utilized to provide the advantages of a vascularized bone flap in complicated pathologies requiring spinal fusion as far as the L2-L3 level, without the morbidity associated with free tissue transfer.

Sociodemographic Factors in Pediatric Epilepsy Surgery.

BACKGROUND: Despite documented efficacy of surgical treatment in carefully selected patients, surgery is delayed and/or underutilized in both adult and children with focal onset epilepsy. The reasons for surgical delay are often assumed or theorized, and studies have predominantly targeted the adult population. To focus on a more targeted pediatric population and to determine identifiable reasons for intervention, this study aimed to investigate time to epilepsy surgery among pediatric patients with medically intractable epilepsy associated with focal cortical dysplasia and to identify sociodemographic and clinical associations in time to epilepsy surgery. METHODS: We reviewed 96 consecutive pediatric patients who underwent surgery for medically intractable epilepsy with a diagnosis of focal cortical dysplasia. Descriptive statistics, univariate and multivariate analyses were conducted to study the association of sociodemographic variables of patients with focal cortical dysplasia and time to epilepsy surgery and postoperative seizure control. RESULTS: We identified that non-white patients on average had a longer duration of epilepsy before surgery and traveled shorter distances for care. Non-white patients were more likely to have government-funded insurance. Patients who traveled the shortest distance to the surgical center underwent epilepsy surgery at an older age. CONCLUSIONS: Sociodemographic factors of travel distance, insurance, and race influenced time to epilepsy surgery for children with focal cortical dysplasia. Further research is warranted to target barriers in access to subspecialty care and develop ways to identify earlier the patients who may benefit from evaluation and deployment of surgical intervention.

Vein of Galen Malformations: The Texas Children's Hospital Experience in the Modern Endovascular Era.

BACKGROUND: Vein of Galen malformations (VOGM) comprise nearly a third of pediatric cerebrovascular anomalies, with potentially devastating neurological and systemic complications. Advances in endovascular therapies have dramatically improved outcomes compared to historical surgical treatments, and neurosurgeons are an essential component of the multidisciplinary critical care team. OBJECTIVE: To retrospectively review pediatric patients with VOGM treated at Texas Children's Hospital (TCH), a quaternary referral center, over 15 yr, and present lessons learned in treating children with modern endovascular techniques. METHODS: Charts from TCH were retrospectively reviewed for the past 15 yr. Patients with diagnosis including "Vein of Galen," "Vein of Galen malformation," "Vein of Galen aneurysmal malformation," or any abbreviations (ie, VOG, VOGM, VOGAM) were reviewed. Presentation, imaging, treatment specifics, and clinical outcomes were reported. RESULTS: There were 18 patients with VOGM managed at TCH from 2002 to 2018 with a total of 29 embolizations. Seventeen were performed with a single embolisate (NBCA or Onyx), and 12 with a combination. A dual lumen balloon catheter was used as an adjunct in 3 embolizations. Complications occurred in 5 embolizations (24%), including hemorrhage, embolisate migration, and femoral vessel occlusion. Surviving patients were followed for a mean of 38 mo, with 12 having normal or near-normal neurological development. CONCLUSION: VOGM can present with a myriad of neurological and systemic symptoms, potentially in extremis. Neurosurgical involvement in these cases is critical, as urgent treatment can be lifesaving. Patients may require multiple treatment sessions using a variety of endovascular tools and techniques.

Outcomes after coverage of lenticulostriate vessels by flow diverters: a multicenter experience.

OBJECTIVE: With the increasing use of flow diversion as treatment for intracranial aneurysms, there is a concomitant increased vigilance in monitoring complications. The low porosity of flow diverters is concerning when the origins of vessels are covered, whether large circle of Willis branches or critical perforators. In this study, the authors report their experience with flow diverter coverage of the lenticulostriate vessels and evaluate their safety and outcomes. METHODS: The authors retrospectively reviewed 5 institutional databases of all flow diversion cases from August 2012 to June 2018. Information regarding patient presentation, aneurysm location, treatment, and outcomes were recorded. Patients who were treated with flow diverters placed in the proximal middle cerebral artery (MCA), proximal anterior cerebral artery, or distal internal carotid artery leading to coverage of the medial and lateral lenticulostriate vessels were included. Clinical outcomes according to the modified Rankin Scale were reviewed. Univariate and multivariate analyses were performed to establish risk factors for lenticulostriate infarct. RESULTS: Fifty-two patients were included in the analysis. Postprocedure cross-sectional images were available in 30 patients. Two patients experienced transient occlusion of the MCA during the procedure; one was asymptomatic, and the other had a clinical and radiographic ipsilateral internal capsule stroke. Five patients had transient symptoms without radiographic infarct in the lenticulostriate territory. Two patients experienced in-stent thrombosis, leading to clinical MCA infarcts (one in the ipsilateral caudate) after discontinuing antiplatelet therapy. Discontinuation of dual antiplatelet therapy prior to 6 months was the only variable that was significantly correlated with stroke outcome (p < 0.01, OR 0.3, 95% CI 0-0.43), and this significance persisted when controlled for other risk factors, including age, smoking status, and aneurysm location. CONCLUSIONS: The use and versatility of flow diversion is increasing, and safety data are continuing to accumulate. Here, the authors provide early data on the safety of covering lenticulostriate vessels with flow diverters. The authors concluded that the coverage of these perforators does not routinely lead to clinically significant ischemia when dual antiplatelet therapy is continued for 6 months. Further evaluation is needed in larger cohorts and with imaging follow-up as experience develops in using these devices in more distal circulation.

Intracranial Venous Hypertension in Craniosynostosis: Mechanistic Underpinnings and Therapeutic Implications.

Patients with complex, multisutural, and syndromic craniosynostosis (CSO) frequently exhibit intracranial hypertension. The intracranial hypertension cannot be entirely attributed to the craniocephalic disproportion with calvarial restriction because cranial vault expansion has not consistently alleviated elevated intracranial pressure. Evidence has most strongly supported a multifactorial interaction, including venous hypertension along with other pathogenic processes. Patients with CSO exhibit marked venous anomalies, including stenosis of the jugular-sigmoid complex, transverse sinuses, and extensive transosseous venous collaterals. These abnormal intracranial-extracranial occipital venous collaterals might represent anomalous development, with persistence and subsequent enlargement of channels normally present in the fetus, either as a primary defect or as nonregression in response to failure of the development of the jugular-sigmoid complexes. It has been suggested by some investigators that venous hypertension in patients with CSO could be treated directly via jugular foraminoplasty, venous stenting, or jugular venous bypass, although these options are not in common clinical practice. Obstructive sleep apnea, occurring as a consequence of midface hypoplasia, can also contribute to intracranial hypertension in patients with syndromic CSO. Thus, correction of facial deformities, as well as posterior fossa decompression, could also play important roles in the treatment of intracranial hypertension. Determining the precise mechanistic underpinnings underlying intracranial hypertension in any given patient with CSO requires individualized evaluation and management.

Anterior Choroidal Artery Aneurysms: Influence of Regional Microsurgical Anatomy on Safety of Endovascular Treatment.

Several anatomical variables critically influence therapeutic strategizing for anterior choroidal artery (AChA) aneurysms, and specifically, the safety of flow diversion for these lesions. We review the microsurgical anatomy of the AChA, discussing and detailing these considerations in the treatment of AChA aneurysms, theoretically and in the light of our recent findings.

Intracranial Erdheim-Chester Disease Mimicking Parafalcine Meningioma: Report of Two Cases and Review of the Literature.

BACKGROUND: Erdheim-Chester disease (ECD) is a rare, non-Langerhans cell histiocytosis that typically occurs in middle-aged patients. It is usually characterized by multifocal osteosclerotic lesions of the long-bones, however many cases have extraskeletal involvement. Central nervous system (CNS) involvement is common, but isolated CNS involvement at presentation has rarely been reported. CASE DESCRIPTION: Here we report two cases of dural-based ECD mimicking meningioma on imaging with no other identified sites of disease. CONCLUSION: ECD is a rare disease, with isolated CNS involvement reported only a few times in the literature. The significance of this presentation requires additional study and long-term follow up.

Multimodal Treatment of Intracranial Aneurysms in Children: Clinical Case Series and Review of the Literature.

BACKGROUND: The management of intracranial aneurysms in the pediatric population presents unique challenges. Cases are rare and tend to be of higher complexity compared with aneurysms in adults. Outcomes in long-term follow-up are not well-characterized. Here we present illustrative case examples to demonstrate key concepts in managing these lesions in the context of the modern neurovascular era. METHODS: Four institutional databases of neurovascular procedures from 2012 to 2017 were reviewed. Patients <18 years old who underwent treatment for intracranial aneurysms were included. Patient characteristics, aneurysm details, treatment information, and angiographic and clinical outcomes were recorded. RESULTS: Ten cases of intracranial aneurysms in 9 children were identified. Management included direct clipping, trapping and bypass, endovascular coil embolization, endovascular vessel sacrifice, and flow diversion. CONCLUSIONS: The management of intracranial aneurysms in pediatric patients requires special considerations, from the diagnostic phase to treatment methods and follow-up regimen. These are ideally considered by a multidisciplinary team, with expertise from pediatric neurosurgeons, cerebrovascular neurosurgeons, and neurointerventionalists.

Unplanned Intraoperative Extubations in Pediatric Neurosurgery: Analysis of Case Series to Increase Patient Safety.

OBJECTIVE: Unplanned intraoperative extubations (UIEs), rare but high-risk events. Unintentional extubations are used as quality improvement metrics in neonatal and pediatric intensive care units, but intraoperative events have received scant attention in the literature. Complexity of patient positioning and proximity of the operative field to anesthesia make neurosurgical procedures unique. UIEs prolong operative time, increase risk of adverse outcomes, including cardiopulmonary collapse, and potentially require additional procedures. Investigating each event is critical to prevention. We aimed to analyze occurrences of UIEs in the pediatric population. METHODS: We retrospectively reviewed UIE cases (12/2014-4/2017) in pediatric neurosurgical patients at a metropolitan pediatric Level I trauma center. Data were collected on patient demographics, procedure, operating room events before the event, and patient outcomes. RESULTS: Over 27 months, 5 UIEs in pediatric neurosurgical cases occurred, with an event rate of <0.3%. Two occurred in patients <1 year old. Two UIEs occurred in patients undergoing surgery for epilepsy. Root cause analysis identified varied etiologies of UIE: 2 were attributed to endotracheal tube securement, 2 were attributed to lighter anesthesia planes in epilepsy cases with limb movement, and 1 occurred while supinating a prone patient. Postoperative outcomes for these patients were no different from routine cases. CONCLUSIONS: Findings suggest an inverse correlation between patient age and UIE, with patient manipulation and anesthesia depth as risk factors. Meticulous attention to securing the endotracheal tube and streamlined communication between the surgical and anesthesia teams are critical for the goal of zero UIE occurrences.

Neurosurgical management of brain metastases.

Brain metastases present a significant public health issue, affecting more than 100,000 patients per year in the U.S. and result in significant morbidity. Brain metastases can occur in a variety of clinical situations ranging from multiple brain metastases with uncontrolled systemic disease to a solitary metastasis in the setting of controlled systemic disease. Additionally, advances in genomics have broadened the opportunities for targeted treatment options and potentially more durable systemic responses. As such, the treatment of brain metastases is now more tailored and multimodal, involving systemic, radiation, and surgical therapies, often in combination. This review discusses the historical and current role of neurosurgical techniques in the treatment of brain metastases.