Adam Wallace

Virtual reality training in neurosurgery: Review of current status and future applications

Background: Over years, surgical training is changing and years of tradition are being challenged by legal and ethical concerns for patient safety, work hour restrictions, and the cost of operating room time. Surgical simulation and skill training offer an opportunity to teach and practice advanced techniques before attempting them on patients. Simulation training can be as straightforward as using real instruments and video equipment to manipulate simulated “tissue” in a box trainer. More advanced virtual reality (VR) simulators are now available and ready for widespread use. Early systems have demonstrated their effectiveness and discriminative ability. Newer systems enable the development of comprehensive curricula and full procedural simulations. Methods: A PubMed review of the literature was performed for the MESH words “Virtual reality, “Augmented Reality”, “Simulation”, “Training”, and “Neurosurgery”. Relevant articles were retrieved and reviewed. A review of the literature was performed for the history, current status of VR simulation in neurosurgery. Results: Surgical organizations are calling for methods to ensure the maintenance of skills, advance surgical training, and credential surgeons as technically competent. The number of published literature discussing the application of VR simulation in neurosurgery training has evolved over the last decade from data visualization, including stereoscopic evaluation to more complex augmented reality models. With the revolution of computational analysis abilities, fully immersive VR models are currently available in neurosurgery training. Ventriculostomy catheters insertion, endoscopic and endovascular simulations are used in neurosurgical residency training centers across the world. Recent studies have shown the coloration of proficiency with those simulators and levels of experience in the real world. Conclusion: Fully immersive technology is starting to be applied to the practice of neurosurgery. In the near future, detailed VR neurosurgical modules will evolve to be an essential part of the curriculum of the training of neurosurgeons.

Endovascular implantation of covered stents in the extracranial carotid and vertebral arteries: Case series and review of the literature

BACKGROUNDnCovered stents are used endovascularly to seal arterial wall defects while preserving vessel patency. This report describes our experience with the use of covered stents to treat cervical pathology, and a review of the literature in regards to this topic is presented.nnnCASE DESCRIPTIONnTwo patients presenting with the carotid blowout syndrome and one patient with a vertebrojugular fistula were treated with covered stents. This allowed for preservation of the vessel and was a treatment alternative to cerebral bypass.nnnCONCLUSIONnCovered stents provide a viable means of preserving the cervical vessels in selected patients; however, long-term follow-up is necessary to determine stent patency and permanency of hemostasis.

Outcome Following Symptomatic Cerebral Vasospasm on Presentation in Aneurysmal Subarachnoid Hemorrhage: Coiling vs. Clipping

BACKGROUNDnCerebral vasospasm complicates both surgical and endovascular treatment of ruptured aneurysms. The present study analyzes patients with presentation vasospasm (PVSP) treated in the acute setting and compares outcomes in those treated with surgical clipping versus endovascular coiling.nnnMETHODSnData from 600 aneurysmal subarachnoid hemorrhage (aSAH) patients who were admitted to the University of Illinois Medical Center in Chicago between June 2002 and July 2007 were retrospectively reviewed. Patients with clinical vasospasm on presentation were compared with patients who developed delayed vasospasm during hospitalization. Subgroup analysis compared outcomes in patients with vasospasm on presentation treated with surgical clipping versus endovascular coiling.nnnRESULTSnOf the 600 aSAH patients, 30 (5%) patients presented with symptomatic vasospasm (PVSP) confirmed by cerebral angiography and 179 (30%) patients were diagnosed with symptomatic vasospasm following admission (delayed vasospasm after admission [DVSP]). Patients admitted with vasospasm showed longer latency to admission after the rupture (5.5 vs. 1.5 day, P ≤ 0.001) but comparable latency to onset of symptomatic vasospasm after rupture. There was no significant difference between the two groups with respect to unfavorable outcome (modified Rankin Scale score > 3), death, or stroke. Therefore, aneurysm treatment during the vasospasm period did not result in increased morbidity in those patients. Within the subgroup of patients presenting with vasospasm on admission, there was no significant difference in outcome between patients who were treated with clipping versus coiling.nnnCONCLUSIONSnOutcome did not differ between aSAH patients treated in the presence of symptomatic vasospasm compared to those with subsequent vasospasm. The outcome of patients presenting with vasospasm was not influenced by the modality of aneurysm treatment. This suggests that both surgical and endovascular intervention for the treatment of ruptured aneurysms are equally valid options in the setting of existing symptomatic vasospasm.

Risk factors for heparin-induced thrombocytopenia type II in aneurysmal subarachnoid hemorrhage.

BACKGROUND Heparin-induced thrombocytopenia type II (HIT II) correlates with a higher incidence of thromboembolic complications and unfavorable outcome. OBJECTIVE To examine the risk factors and outcomes for patients with HIT II with aneurysmal subarachnoid hemorrhage. METHODS Demographics, risk factors, treatments, and outcomes data of 600 aneurysmal subarachnoid hemorrhage patients admitted to the University of Illinois Medical Center in Chicago between June 2002 and July 2007 were retrospectively reviewed. Patients meeting the clinical criteria for HIT II were compared with those who did not develop thrombocytopenia. RESULTS Twenty-five patients (6%) met the clinical criteria for HIT II, and 396 (94%) did not develop thrombocytopenia. Both groups were the same with respect to age, Hunt-Hess score and Fisher grade on admission, medical conditions, and social risk factors. The HIT II patients had significantly more unfavorable outcomes (modified Rankin Scale score >3), deep vein thrombosis, stroke, pulmonary embolism, and death. Development of HIT II was strongly associated with symptomatic vasospasm (odds ratio, 5.7; 95% confidence interval, 2.5-13.1; P < .001) and number of angiographic procedures (odds ratio, 1.7; 95% confidence interval, 1.3-2.2; P < .001). Forward buildup selection modeling demonstrated the latter to be the strongest predictor for HIT II development (odds ratio, 2.3; 95% confidence interval, 1.7-3.2; P = .02). CONCLUSION Heparin-induced thrombocytopenia type II correlates with a worse outcome and higher risk of thromboembolic complications in aneurysmal subarachnoid hemorrhage patients. In addition, HIT II was strongly associated with the number of angiographic procedures performed during the same hospitalization. ABBREVIATIONS ACCP: American College of Chest Physicians aSAH: aneurysmal subarachnoid hemorrhage CI: confidence interval DVT: deep vein thrombosis HIT II: heparin-induced thrombocytopenia type II LMWH: low-molecular-weight heparin SAH: subarachnoid hemorrhage UFH: unfractionated heparin

Effect of Acute Cocaine Use on Vasospasm and Outcome in Aneurysmal Subarachnoid Hemorrhage

BACKGROUNDnAlthough acute cocaine use has been correlated with aneurysmal subarachnoid hemorrhage, its effect on vasospasm and outcome is controversial. We investigated the effect of acute cocaine use on response to vasospasm treatment and neurologic outcome in patients with aneurysmal subarachnoid hemorrhage.nnnMETHODSnData from 600 patients with aneurysmal subarachnoid hemorrhage admitted to the University of Illinois Medical Center in Chicago between June 2002 and July 2007 were retrospectively analyzed. Patients who were positive for cocaine on urine toxicology or admitted to cocaine use within 72 hours of admission were compared with control patients with no history of cocaine use. Patients with unknown or remote history were excluded.nnnRESULTSnOf the 600 patients with aneurysmal subarachnoid hemorrhage, 27 (5%) were excluded. Thirty-one patients (5%) acutely used cocaine before admission. Cocaine users were younger than control (45.1 vs 54.1; P ≤ .0003), and were more likely to smoke tobacco, drink alcohol, and have renal dysfunction. There was no significant difference in Hunt-Hess or Fisher grade. In univariate and multivariate analyses, there was no difference in unfavorable short-term outcome (modified Rankin scale > 3), incidence of symptomatic or radiologic vasospasm, stroke, or death. The number of interventional procedures for the treatment of vasospasm did not differ between the two groups.nnnCONCLUSIONSnThere is no significant difference in incidence of symptomatic vasospasm or neurologic outcome between cocaine users and nonusers. The severity of the vasospasm and the response to treatment, as indicated by the number of vasospasm interventions, did not differ between the two groups.

Heparin induced thrombocytopenia: diagnosis and management

The incidence of heparin induced thrombocytopenia (HIT) in neurological patients continues to increase with expansion of indication for neurointerventional procedures. The pathophysiology of HIT is related to a hypersensitivity reaction against complex platelet factor 4. The diagnosis is mostly clinical and is often confirmed by laboratory testing. Patients with HIT have a higher rate of thromboembolic complications, both arterial and venous, and with worse neurological outcomes at the time of discharge. Early diagnosis and heparin cessation are essential in the management of those patients. Both immediate and prolonged alternative anticoagulation are necessary. Understanding of the mechanism of action, indication and drug interaction of the alternative anticoagulants (direct thrombin inhibitors, fondaparinux and danaparoid) and warfarin is essential during management of these patients.

Endovascular parent vessel sacrifice in ruptured dissecting vertebral and posterior inferior cerebellar artery aneurysms: clinical outcomes and review of the literature

Background Ruptured intracranial dissecting aneurysms must be secured quickly to prevent re-hemorrhage. Endovascular sacrifice of the diseased segment is a well-established treatment method, however postoperative outcomes of symptomatic stroke and re-hemorrhage rates are not well reported, particularly for the perforator-rich distal vertebral artery or proximal posterior inferior cerebellar artery (PICA). Methods We retrospectively reviewed cases of ruptured distal vertebral artery or PICA dissecting aneurysms that underwent endovascular treatment. Diagnosis was based on the presence of subarachnoid hemorrhage on initial CT imaging and of a dissecting aneurysm on catheter angiography. Patients with vertebral artery aneurysms were selected for coil embolization of the diseased arterial segment based on the adequacy of flow to the basilar artery from the contralateral vertebral artery. Patients with PICA aneurysms were generally treated only if they were poor surgical candidates. Outcomes included symptomatic and asymptomatic procedure-related cerebral infarction, recurrent aneurysm rupture, angiographic aneurysm recurrence, and estimated modified Rankin Scale (mRS). Results During the study period, 12 patients with dissecting aneurysms involving the distal vertebral artery (n=10) or PICA (n=2) were treated with endovascular sacrifice. Two patients suffered an ischemic infarction, one of whom was symptomatic (8.3%). One patient (8.3%) died prior to hospital discharge. No aneurysm recurrence was identified on follow-up imaging. Ten patients (83%) made a good recovery (mRS ≤2). Median clinical and imaging follow-up periods were 41.7u2005months (range 0–126.4u2005months) and 14.3u2005months (range 0.03–88.6u2005months), respectively. Conclusions In patients with good collateral circulation, endovascular sacrifice may be the preferred treatment for acutely ruptured dissecting aneurysms involving the distal vertebral artery.

Drill-Assisted Biopsy of the Axial and Appendicular Skeleton: Safety, Technical Success, and Diagnostic Efficacy

The purpose of this study was to evaluate the safety, technical success rate, and diagnostic efficacy of drill-assisted axial and appendicular bone biopsies. During a 3-y period, 703 drill-assisted biopsies were performed. The cohort included 54.2% men, with a mean age of 57.6 y ± 17.1. Median lesion volume was 10.9 mL (interquartile range, 3.4-30.2 mL). Lesions were lytic (31.7%), sclerotic (21.2%), mixed lytic and sclerotic (27.7%), or normal radiographic bone quality (19.3%). No complications were reported. The technical biopsy success rate was 99.9%. Crush artifact was present in 5.8% of specimens submitted for surgical pathologic examination, and 2.1% of specimens were inadequate for histologic evaluation.

Balloons in endovascular neurosurgery: history and current applications.

The use of balloons in the field of neurosurgery is currently an essential part of our clinical practice. The field has evolved over the last 40 years since Serbinenko used balloons to test the feasibility of occluding cervical vessels for intracranial pathologies. Since that time, indications have expanded to include sacrificing cervical and intracranial vessels with detachable balloons, supporting the coil mass in wide-necked aneurysms (balloon remodeling technique), and performing intracranial and cervical angioplasty for atherosclerotic disease, as well as an adjunct to treat arteriovenous malformations. With the rapid expansion of endovascular technologies, it appears that the indications and uses for balloons will continue to expand. In this article, we review the history of balloons, the initial applications, the types of balloons available, and the current applications available for endovascular neurosurgeons.The use of balloons in the field of neurosurgery is currently an essential part of our clinical practice. The field has evolved over the last 40 years since Serbinenko used balloons to test the feasibility of occluding cervical vessels for intracranial pathologies. Since that time, indications have expanded to include sacrificing cervical and intracranial vessels with detachable balloons, supporting the coil mass in wide-necked aneurysms (balloon remodeling technique), and performing intracranial and cervical angioplasty for atherosclerotic disease, as well as an adjunct to treat arteriovenous malformations. With the rapid expansion of endovascular technologies, it appears that the indications and uses for balloons will continue to expand. In this article, we review the history of balloons, the initial applications, the types of balloons available, and the current applications available for endovascular neurosurgeons.

Primitive neuroectodermal tumor after radiation therapy for craniopharyngioma.

The authors report a case of primitive neuroectodermal tumor induced by radiation therapy of craniopharyngioma. This African-American male patient originally presented with craniopharyngioma, for which he underwent resection and whole-brain radiation therapy. Eight years later, at the age of 20 years, he returned with a left facial droop and left hemiparesis. A right basal ganglia mass was identified and resected. Histopathological examination identified the lesion as primitive neuroectodermal tumor. Although radiation therapy has shown to be beneficial in decreasing the recurrence rate in subtotally resected craniopharyngioma, the risks of radiation treatment should be clearly communicated to the patients, their families, and neurosurgeons before starting such treatment. This report expands the spectrum of reported radiation-induced neoplasms in the CNS.