Matthew R. Sanborn

Temporal dynamics of microparticle elevation following subarachnoid hemorrhage

OBJECT Microparticles (MPs), small membrane fragments shed from various cell types, have been implicated in thrombosis, inflammation, and endothelial dysfunction. Their involvement in subarachnoid hemorrhage (SAH) and the development of cerebral infarction and clinical deterioration caused by delayed cerebral ischemia (DCI) remain ill defined. The authors sought to quantify the magnitude of elevations in MPs, delineate the temporal dynamics of elevation, and analyze the correlation between MPs and DCI in patients with SAH. METHODS On the day of hemorrhage and on Days 1, 3, 5, 7, and 10 after hemorrhage, peripheral blood samples were drawn from 22 patients with SAH. Plasma samples were labeled with Annexin V and CD142, CD41a, CD235a, CD146, CD66b, or von Willebrand factor (vWF) and were quantified by flow cytometry. Clinical data, including the 3-month extended Glasgow Outcome Scale (GOS-E) scores, infarction as measured on MRI at 14 days after SAH, and vasospasm as measured by transcranial Doppler ultrasonography and angiography, were collected and compared with the MP burden. RESULTS When averaged over time, all MP subtypes were elevated relative to controls. The CD235a+(erythrocyte)-, CD66b+(neutrophil)-, and vWF-associated MPs peaked on the day of hemorrhage and quickly declined. The CD142+(tissue factor [TF])-associated MPs and CD146+(endothelial cell)-associated MPs were significantly elevated throughout the study period. There was a strong negative correlation between TF-expressing and endothelial-derived MPs at Day 1 after SAH and the risk of infarction at Day 14 after SAH. CONCLUSIONS Microparticles of various subtypes are elevated following SAH; however, the temporal profile of this elevation varies by subtype. Those subtypes closely associated with thrombosis and endothelial dysfunction, for example, CD145+(TF)-associated MPs and CD146+(endothelial cell)-associated MPs, had the most durable response and demonstrated a significant negative correlation with radiographic infarction at 14 days after SAH. Levels of these MPs predict infarction as early as Day 1 post-SAH.

Re-treatment rates after treatment with the Pipeline Embolization Device alone versus Pipeline and coil embolization of cerebral aneurysms: a single-center experience.

OBJECT The optimal strategy for use of the Pipeline Embolization Device (PED, ev3 Neurovascular) has not been clearly defined. The authors examined re-treatment rates after treatment with PED alone versus PED and adjunctive coil embolization (PED/coil). METHODS The authors retrospectively examined cerebral aneurysms treated with the PED from May 2011 to March 2014. Overall, 133 patients (25 men, 108 women; mean age 60.4 years, range 23-85 years) were treated for 140 aneurysms (mean size 11.8 ± 8.3 mm) requiring 224 PEDs (mean 1.7 PEDs per patient). Sixty-eight patients (13 men, 55 women) were treated with PED alone for 73 aneurysms (mean size 10.6 ± 9.2 mm) and 65 patients (12 men, 53 women) were treated with PED/coil for 67 aneurysms (mean size 12.8 ± 7.4 mm). RESULTS Eight aneurysms in 8 patients were re-treated in the PED-alone cohort versus only 1 aneurysm in 1 patient in the PED/coil cohort for re-treatment rates of 11.8% (8/68) and 1.5% (1/65), respectively (p = 0.03). Two patients in the PED-alone cohort were re-treated due to PED contraction, while the other 6 were re-treated for persistent filling of the aneurysms. The PED/coil patient experienced continued filling of a vertebrobasilar artery aneurysm. No aneurysms in either group ruptured after treatment. CONCLUSIONS Adjunctive coil embolization during flow diversion with the PED resulted in a significantly lower re-treatment rate compared with PED alone, suggesting an added benefit with adjunctive coil embolization. This result may provide the basis for future evaluation with randomized, controlled trials.

Cost-effectiveness of confirmatory techniques for the placement of lumbar pedicle screws

OBJECT There is considerable variation in the use of adjunctive technologies to confirm pedicle screw placement. Although there is literature to support the use of both neurophysiological monitoring and isocentric fluoroscopy to confirm pedicle screw positioning, there are no studies examining the cost-effectiveness of these technologies. This study compares the cost-effectiveness and efficacy of isocentric O-arm fluoroscopy, neurophysiological monitoring, and postoperative CT scanning after multilevel instrumented fusion for degenerative lumbar disease. METHODS Retrospective data were collected from 4 spine surgeons who used 3 different strategies for monitoring of pedicle screw placement in multilevel lumbar degenerative disease. A decision analysis model was developed to analyze costs and outcomes of the 3 different monitoring strategies. A total of 448 surgeries performed between 2005 and 2010 were included, with 4 cases requiring repeat operation for malpositioned screws. A sample of 64 of these patients was chosen for structured interviews in which the EuroQol-5D questionnaire was used. Expected costs and quality-adjusted life years were calculated based on the incidence of repeat operation and its negative effect on quality of life and costs. RESULTS The decision analysis model demonstrated that the O-arm monitoring strategy is significantly (p < 0.001) less costly than the strategy of postoperative CT scanning following intraoperative uniplanar fluoroscopy, which in turn is significantly (p < 0.001) less costly than neurophysiological monitoring. The differences in effectiveness of the different monitoring strategies are not significant (p = 0.92). CONCLUSIONS Use of the O-arm for confirming pedicle screw placement is the least costly and therefore most cost-effective strategy of the 3 techniques analyzed.

Endoscopic, endonasal, transclival resection of a pontine cavernoma: case report.

BACKGROUND AND IMPORTANCE: Hemorrhagic, symptomatic cavernous malformations in the brainstem are difficult to access. Conventional approaches such as the transpetrosal approach often require significant brain retraction. We present the successful purely endoscopic, endonasal, transclival resection of a symptomatic cavernoma located in the ventromedial pons. CLINICAL PRESENTATION: A 17-year-old male patient presented with acute onset of headache, facial numbness, and tingling. Magnetic resonance imaging demonstrated an enhancing lesion in the pons consistent with a cavernous malformation. Over the course of the next 3 weeks, the patient had 2 additional episodes of acutely worsening neurological deficits that left him with left-sided hemiparesis, a right sixth nerve palsy, and dysphagia. A purely endoscopic, endonasal, transclival approach was used to resect the cavernoma. Postoperatively, he had a transient worsening of his left-side motor function and restricted horizontal gaze, but at the last follow-up, his hemiparesis had improved and his magnetic resonance imaging demonstrated a radiographic cure. He developed a cerebrospinal fluid (CSF) leak despite prophylactic lumbar CSF drainage for 2 days and the use of bilateral vascularized nasoseptal flaps. The CSF leak was repaired with CSF diversion and a second surgical procedure; at the last follow-up, he had no recurrence of the leak. CONCLUSION: An endoscopic, endonasal, transclival approach is a novel and effective approach to cavernous malformations presenting to the ventral surface of the pons. Recently developed techniques for closure and repair of the skull base defect have minimized but have not eliminated the risk of CSF leak in these procedures. ABBREVIATIONS: BSCM, brainstem cavernous malformation CM, cavernous malformation

Treatment of steroid refractory, Gamma Knife related radiation necrosis with bevacizumab: Case report and review of the literature

Radiation necrosis is the most significant complication associted with Gamma Knife radiosurgery. It typically becomes manifest s a necrotic white matter lesion 3 or more months following treatent [3]. Treatment volume and radiation dose are the two most mportant predictors of radiation necrosis. Once radiation necrois has become clinically apparent treatment has historically been imited to corticosteroids. Antiplatelet agents, anticoagulants and yperbaric oxygen have been studied but there is currently minimal igh quality evidence to support their use in routine clinical pracice [6]. If the radiation necrosis fails to respond to steroid treatment herapeutic options are limited. Recent trials have highlighted a potential role for bevacizumab, a onoclonal antibody directed against vascular endothelial growth actor (VEGF) in the treatment of radiation necrosis from convenional radiation therapy [14]. We present a case of symptomatic adiation necrosis following Gamma Knife radiosurgery for muliple atypical WHO grade II meningiomas initially unresponsive o steroid treatment and ultimately responsive to bevacizumab herapy.

Safety and efficacy of a novel ultrasonic osteotome device in an ovine model

The use of ultrasonic technology for bone removal offers the potential advantages over the use of traditional hand instruments or cutting burrs of more precise bone resection and reduced soft-tissue injury. While the use of modified ultrasonic aspirators has been described for bone removal in spinal surgery, none of these instruments has been systematically examined to evaluate safety and efficacy. Thus, we compared laminectomies using traditional instruments, and traditional instruments with an ultrasonic osteotome, in an ovine model. We used a combination of clinical examination, intra-operative and post-operative neuromonitoring and histological analysis to evaluate safety. The secondary endpoint of efficiency was assessed by examining operative times. No significant difference was found between groups in neurophysiology or the Tarlov clinical rating scale. Histology revealed inflammatory or reparative changes in 6/8 experimental animals and 2/4 control animals with a single section in an experimental animal revealing focal nerve root disruption and mild axonal loss. A single durotomy was noted in both the control and experimental groups. Operative time for the experimental group was significantly shorter than the operative time for the control group.

Thalamic Deep Brain Stimulation for Midbrain Tremor Secondary to Cystic Degeneration of the Brainstem

Objective: Tremor resulting from damage to midbrain structures is poorly understood and often difficult to treat. The authors report a case of cystic degeneration of the brainstem with resultant Holmes-like tremor which was successfully treated using a stimulating electrode placed in the contralateral ventralis intermedius nucleus (VIM) of the thalamus. Clinical Presentation: A 31-year-old man presented with a multilobulated, multiseptated lesion of the upper brainstem diagnosed after subacute onset of headaches. The patient subsequently developed an incapacitating left-upper-extremity tremor refractory to medical treatment. Intervention: The patient underwent implantation of a deep brain stimulator in the VIM with symptomatic and functional improvement. Conclusions: Deep brain stimulation is an effective and safe intervention for tremor of unusual etiology. Electrode placement should be based on an understanding of the structure-function relationships underlying the various and distinct types of tremor.

Endoscopic approaches to brainstem cavernous malformations: Case series and review of the literature

Background: Symptomatic cavernous malformations involving the brainstem are frequently difficult to access via traditional methods. Conventional skull-base approaches require significant brain retraction or bone removal to provide an adequate operative corridor. While there has been a trend toward limited employment of the most invasive surgical approaches, recent advances in endoscopic technology may complement existing methods to access these difficult to reach areas. Case Descriptions: Four consecutive patients were treated for symptomatic, hemorrhagic brainstem cavernous malformations via fully endoscopic approaches (endonasal, transclival; retrosigmoid; lateral supracerebellar, infratentorial; endonasal, transclival). Together, these lesions encompassed all three segments of the brainstem. Three of the patients had complete resection of the cavernous malformation, while one patient had stable residual at long-term follow up. Associated developmental venous anomalies were preserved in the two patients where one was identified preoperatively. Three of the four patients maintained stable or improved neurological examinations following surgery, while one patient experienced ipsilateral palsies of cranial nerves VII and VIII. The first transclival approach resulted in a symptomatic cerebrospinal fluid leak requiring re-operation, but the second did not. Although there are challenges associated with endoscopic approaches, relative to our prior microsurgical experience with similar cases, visualization and illumination of the surgical corridors were superior without significant limitations on operative mobility. Conclusion: The endoscope is a promising adjunct to the neurosurgeons ability to approach difficult to access brainstem cavernous malformations. It allows the surgeon to achieve well-illuminated, panoramic views, and by combining approaches, can provide minimally invasive access to most regions of the brainstem.

A patient with thoracic intradural disc herniation

Intradural disc herniation is a rare disease that occurs most commonly in the lumbar region, while fewer than 5% occur in the thoracic and cervical regions. We report a patient with thoracic intradural disc herniation at T12-L1 who presented with radiculopathy and motor weakness. The preoperative MRI did not demonstrate an intradural lesion, and it was identified intraoperatively by inspection and palpation of the thecal sac. The disc was removed, and the patient experienced good neurological recovery and remains pain free 1 year after surgery.

Glioblastoma multiforme in the adult conus medullaris

De novo glioblastoma multiforme (GBM) of the spine is rare. We present a patient with a unique GBM arising within the conus and radiographically mimicking a filum terminale ependymoma. During surgery the lesion was notable for its highly vascular and diffuse infiltration of the surrounding spinal cord parenchyma. The operative goals were altered to account for the unexpected pathology. The treatment and prognosis of spinal GBM are briefly reviewed and the importance of considering an aggressive pathology when formulating a surgical plan for benign appearing lesions is emphasized.