Thomas Ostergard

Cerebral amyloid angiopathy–associated intracerebral hemorrhage: pathology and management

Amyloid angiopathy-associated intracerebral hemorrhage (ICH) comprises 12%-15% of lobar ICH in the elderly. This growing population has an increasing incidence of thrombolysis-related hemorrhages, causing the management of hemorrhages associated with cerebral amyloid angiopathy (CAA) to take center stage. A concise reference assimilating the pathology and management of this clinical entity does not exist. Amyloid angiopathy-associated hemorrhages are most often solitary, but the natural history often progresses to include multifocal and recurrent hemorrhages. Compared with other causes of ICH, patients with CAA-associated hemorrhages have a lower mortality rate but an increased risk of recurrence. Unlike hypertensive arteriolar hemorrhages that occur in penetrating subcortical vessels, CAA-associated hemorrhages are superficial in location due to preferential involvement of vessels in the cerebral cortex and meninges. This feature makes CAA-associated hemorrhages easier to access surgically. In this paper, the authors discuss 3 postulates regarding the pathogenesis of amyloid hemorrhages, as well as the established clinicopathological classification of amyloid angiopathy and CAA-associated ICH. Common inheritance patterns of familial CAA with hemorrhagic strokes are discussed along with the role of genetic screening in relatives of patients with CAA. The radiological characteristics of CAA are described with specific attention to CAA-associated microhemorrhages. The detection of these microhemorrhages may have important clinical implications on the administration of anticoagulation and antiplatelet therapy in patients with probable CAA. Poor patient outcome in CAA-associated ICH is associated with dementia, increasing age, hematoma volume and location, initial Glasgow Coma Scale score, and intraventricular extension. The surgical management strategies for amyloid hemorrhages are discussed with a review of published surgical case series and their outcomes with a special attention to postoperative hemorrhage.

Motor cortex stimulation for chronic pain.

Motor cortex stimulation produces significant relief of symptoms in many forms of refractory chronic pain disorders.

Animal models of post-traumatic epilepsy

Post-traumatic epilepsy (PTE) is defined as the development of unprovoked seizures in a delayed fashion after traumatic brain injury (TBI). PTE lies at the intersection of two distinct fields of study, epilepsy and neurotrauma. TBI is associated with a myriad of both focal and diffuse anatomic injuries, and an ideal animal model of epilepsy after TBI must mimic the characteristics of human PTE. The three most commonly used models of TBI are lateral fluid percussion, controlled cortical injury, and weight drop. Much of what is known about PTE has resulted from use of these models. In this review, we describe the most commonly used animal models of TBI with special attention to their advantages and disadvantages with respect to their use as a model of PTE.

Prolonged Intracisternal Papaverine Toxicity: Index Case Description and Proposed Mechanism of Action

BACKGROUND Intracisternal papaverine (iPPV) is a vasodilator used for prophylaxis of intraoperative vasospasm during aneurysmal clipping. Postoperative side effects of iPPV include transient cranial nerve palsies, most commonly mydriasis owing to oculomotor nerve involvement, with rapid resolution. METHODS We critically reviewed current literature on the adverse effects of iPPV in aneurysmal surgery with a focus on oculomotor nerve involvement. We also present the index case of prolonged bilateral mydriasis secondary to iPPV irrigation toxicity and its putative underlying mechanism. RESULTS Papaverine toxicity occurs in the setting of its antimuscarinic action and blood-cerebrospinal fluid and blood-brain barrier compromise owing to acute subarachnoid hemorrhage and direct effect of papaverine. Our patient also experienced severe vasospasm and a minor stroke, both contributing to further blood-brain barrier disruption, and relatively acidic pH of the subarachnoid hemorrhage milieu. CONCLUSIONS We propose that these factors perpetuate phase dynamics of papaverine crystals and facilitate a sustained slow release of papaverine within the cisternal system. Were it indicated, 0.3% iPPV would reasonably diminish the risk for neurotoxicity.

High Cervical Ependymoma Resection: 2-Dimensional Operative Video

This operative video illustrates resection of a cervical ependymoma in a 40-yr-old female with numbness of upper and lower extremities and ataxia. Magnetic resonance imaging (MRI) demonstrated an enhancing intramedullary intradural spinal mass at C2-3. The patient underwent a posterior cervical laminoplasty for tumor resection. This video highlights the natural history of this disease, treatment options, surgical procedure, potential risks and complications, and postoperative management of ependymomas. A posterior midline skin incision was made from the inion to the level of C4 which exposed the posterolateral elements of C1-3. C2 and C3 lamina were removed as a single piece using the high-speed drill. A C1 laminectomy was then also performed to provide adequate superior exposure. The dura was opened widely in the midline. Careful midline myelotomy was then performed overlying the tumor. The tumor is noted to be densely adherent to the surrounding spinal cord. Gross total resection was completed using ultrasonic aspiration and microdissection. The dura was closed in a watertight fashion followed by a synthetic dural sealant. The bony elements of C2, C3 were then reconstructed using osteoplastic laminoplasty, titanium miniplates, and screws at C2-3. The wound was closed in multiple layers using sutures. Specimens were sent for frozen and permanent pathological analysis, eventually demonstrating WHO grade II ependymoma. There were no complications. Postoperative MRI demonstrated gross total resection. The patient had an uneventful postoperative course. The strength was at baseline at long term follow-up, with small sensory deficit.

Posterior Cervical Laminoplasty for Resection Intradural Extramedullary Spinal Meningioma: 2-Dimensional Operative Video

This operative video demonstrates a posterior cervical laminoplasty for the resection of a cervical intradural extramedullary meningioma. In addition, the natural history, treatment options, and potential complications are discussed. The patient is a 68-yr-old male who presented with left-hand grip weakness and paresthesias. Magnetic resonance imaging (MRI) demonstrated an enhancing mass that displacing the spinal cord anteriorly and causing severe flattening of the cord at C4 and C5. The patient underwent a posterior cervical laminoplasty for tumor resection. Removal of the dorsal elements with a high-speed drill was performed at C3, C4, and C5. A midline durotomy was performed and a large extra-axial intradural tumor was encountered. The tumor was resected en bloc and specimens were sent for permanent pathological analysis. The dura was closed in a watertight fashion using 6-0 Prolene sutures. The laminoplasty was performed by using titanium miniplates and screws to reconstruct the dorsal bony elements, and the wound was closed in layers using sutures. There were no complications. Final pathology was consistent with a WHO grade I meningioma. Postoperative MRI demonstrated gross total resection. The patients perioperative course was uncomplicated and his preoperative weakness completely resolved by time of discharge.

Resection of a Thoracic Hemangioblastoma in a Patient With Von Hippel-Lindau: 3-Dimensional Operative Video

This 3-dimensional operative video illustrates resection of a thoracic hemangioblastoma in a 30-year-old female with a history of Von Hippel-Lindau disease. The patient presented with right lower extremity numbness and flank pain. Magnetic resonance imaging (MRI) demonstrated an enhancing intradural intramedullary lesion at T 7 consistent with a hemangioblastoma. The patient underwent a thoracic laminectomy with a midline dural opening for tumor resection. This case demonstrates the principles of intradural intramedullary spinal cord tumor resection. In this particular case, internal debulking was untenable owing to the vascular nature of hemangioblastomas. The operative video demonstrates en bloc tumor removal. Postoperative MRI demonstrated gross total resection. The postoperative course was uneventful. The natural history of this disease, treatment options, and potential complications are discussed.

Resection of a Lumbar Intradural Extramedullary Schwannoma: 3-Dimensional Operative Video

This 3-dimensional operative video illustrates resection of a lumbar schwannoma in a 57-yr-old female who presented with right lower extremity numbness, paresthesias, as well as a long history of lower back pain with rest. On magnetic resonance imaging (MRI), there was evidence of an intradural extramedullary enhancing lesion at L5, nearly completely encompassing the spinal canal. This video demonstrates the natural history, treatment options, surgical procedure, risks, and complications of treatment of these types of tumors. The patient underwent a posterior lumbar laminectomy with a midline dural opening for tumor resection. The tumor was encountered intradurally and electromyography recording confirmed that the tumor arose from a lumbar sensory nerve root. The sensory root was then divided and the tumor was then removed. The mass was removed en bloc and histopathologic analysis was consistent with a schwannoma. Postoperative MRI demonstrated gross total resection of the patients neoplasm with excellent decompression of the spinal cord. The patient had an uneventful postoperative course with full recovery and complete resolution of her back pain and leg paresthesias.

Resection of 2 Intradural Extramedullary Cervical Spine Tumors in a Patient With Neurofibromatosis Type 2: 3-Dimensional Operative Video

This 3-dimensional operative video illustrates resection of 2 cervical spine schwannomas in a 19-yr-old female with neurofibromatosis type 2. The patient presented with lower extremity hyperreflexity and hypertonicity. Magnetic resonance imaging (MRI) demonstrated 2 contrast-enhancing intradural extramedullary cervical spine lesions causing spinal cord compression at C4 and C5. The patient underwent a posterior cervical laminoplasty with a midline dural opening for tumor resection. Curvilinear spine cord compression is demonstrated in the operative video. After meticulous dissection, the tumors were resected without complication. The dural closure was performed in watertight fashion followed by laminoplasty using osteoplastic titanium miniplates and screws. Postoperative MRI demonstrated gross total resection with excellent decompression of the spinal cord. The postoperative course was uneventful. The natural history of this disease, treatment options, and potential complications are discussed.

Is the Supraorbital Notch a Reliable Landmark to Avoid the Frontal Sinus

BACKGROUND When performing a craniotomy involving the orbital bar, the supraorbital notch is a potential landmark to localize the lateral extent of the frontal sinus. Avoidance of the frontal sinus is important to reduce the risk of postoperative surgical site infection, epidural abscess formation, and mucocele development. OBJECTIVE To determine the reliability of the supraorbital notch as a marker of the lateral location of the frontal sinus. METHODS Cadaveric dissections were used with image guidance software to define the relationship between the frontal sinus and supraorbital foramen. RESULTS The supraorbital notch was located 2.54 cm from midline and the lateral extent of the frontal sinus extended 2.84 mm lateral to the supraorbital notch. When performing a craniotomy extending medially to the supraorbital notch at a perpendicular angle, the frontal sinus was breached in 65% of craniotomies. When the craniotomy ended 10 mm lateral to the supraorbital notch, the rate of frontal sinus breach decreased to 10%. CONCLUSION When performing a craniotomy involving the supraorbital notch, a lateral to medial trajectory that ends 15 mm to the supraorbital notch will minimize the risk of frontal sinus violation.