A Suggestion of Modified Classification of Trigeminal Schwannomas According to Location, Shape, and Extension

BACKGROUND: Comprehensive knowledge of the anatomical features of trigeminal schwannomas (TSs) is essential in planning surgery to achieve complete tumor resection. In the current report, we propose a modified classification of TSs according to their location of origin, shape, and extension into the adjacent compartment, and discuss appropriate surgical strategies with this classification. METHODS: We retrospectively analyzed 49 patients with TS who were treated surgically by a single neurosurgeon at the Asan Medical Center between 1993 and 2013. RESULTS: There were 22 males and 27 females, with the median age of 40 years (range, 21-75 years). Median tumor size was 4.0 cm in diameter (2.0-7.0 cm). Tumors were classified as follows: Type M (confined to the middle fossa; 8 cases, 19.0%), P (confined to the posterior fossa; 2 cases, 4.8%), MP (involving equally both middle and posterior fossae; 5 cases, 11.9%), Mp (predominantly middle fossa with posterior fossa extension; 6 cases, 14.3%), Pm (predominantly posterior fossa with middle fossa extension; 16 cases, 38.1%), Me (predominantly middle fossa with extracranial extension; 4 cases, 9.5%). Surgical approach was chosen depending on the tumor classification. More specifically, a frontotemporal craniotomy and extradural approach with or without zygomatic or orbitozygomatic osteotomy was applied to M- or Mp-type tumors; a lateral suboccipital craniotomy with or without suprameatal approach was applied to the majority of P- or Pm-type tumors; and a posterior transpetrosal approach was used in four tumors (three Pm and one MP). Gross total resection was achieved in 95.9% of patients, and the overall recurrence rate was 4.1% (2 patients). Postoperatively, trigeminal symptoms were improved or unchanged in 51.0% of cases (25 patients). Surgical complications included meningitis (5 patients) and cerebrospinal fluid leakage (3 patients). There was no mortality. CONCLUSION: TSs are well to be classified with our modified classification and able to be removed effectively and safely by selecting appropriate surgical approaches.

Unilateral Posterior Atlantoaxial Transarticular Screw Fixation in Patients with Atlantoaxial Instability : Comparison with Bilateral Method

OBJECTIVE: Bilateral C1-2 transarticular screw fixation (TAF) with interspinous wiring has been the best treatment for atlantoaxial instability (AAI). However, several factors may disturb satisfactory placement of bilateral screws. This study evaluates the usefulness of unilateral TAF when bilateral TAF is not available. METHODS: Between January 2003 and December 2007, TAF was performed in 54 patients with AAI. Preoperative studies including cervical x-ray, three dimensional computed tomogram, CT angiogram, and magnetic resonance image were checked. The atlanto-dental interval (ADI) was measured in preoperative period, immediate postoperatively, and postoperative 1, 3 and 6 months. RESULTS: Unilateral TAF was performed in 27 patients (50%). The causes of unilateral TAF were anomalous course of vertebral artery in 20 patients (74%), severe degenerative arthritis in 3 (11%), fracture of C1 in 2, hemangioblastoma in one, and screw malposition in one. The mean ADI in unilateral group was measured as 2.63 mm in immediate postoperatively, 2.61 mm in 1 month, 2.64 mm in 3 months and 2.61 mm in 6 months postoperatively. The mean ADI of bilateral group was also measured as following; 2.76 mm in immediate postoperative, 2.71 mm in 1 month, 2.73 mm in 3 months, 2.73 mm in 6 months postoperatively. Comparison of ADI measurement showed no significant difference in both groups, and moreover fusion rate was 100% in bilateral and 96.3% in unilateral group (p=0.317). CONCLUSION: Even though bilateral TAF is best option for AAI in biomechanical perspectives, unilateral screw fixation also can be a useful alternative in otherwise dangerous or infeasible cases through bilateral screw placement.

Extravasation during Aneurysm Embolization without Neurologic Consequences. Lessons learned from Complications of Pseudoaneurysm Coiling. Report of 2 Cases

Although endovascular intervention is the first-line treatment of intracranial aneurysm, intraprocedural rupture or extravasation is still an endangering event. We describe two interesting cases of extravasation during embolotherapy for ruptured peripheral cerebral pseudoaneurysms. Two male patients were admitted after development of sudden headache with presentation of intracerebral and subarachnoid hemorrhage, respectively. Initial angiographic assessment failed to uncover any aneurysmal dilatation in both patients. Two weeks afterwards, catheter angiography revealed aneurysms each in the peripheral middle cerebral artery and anterior inferior cerebellar artery. Under a general anesthesia, endovascular embolization was attempted without systemic heparinization. In each case, sudden extravasation was noted around the aneurysm during manual injection of contrast after microcatheter navigation. Immediate computed tomographic scan showed a large amount of contrast collection within the brain, but they tolerated and made an unremarkable recovery thereafter. Intraprocedural extravasation is an endangering event and needs prompt management, however proximal plugging with coil deployment can be sufficient alternative, if one confronts with peripheral pseudoaneurysm. Peculiar angiographic features are deemed attributable to extremely fragile, porous vascular wall of the pseudoaneurysm. Accordingly, it should be noted that extreme caution being needed to handle such a friable vascular lesion.

Ruptured Cerebral Aneurysm without Subarachnoid Hemorrhage: Who needs angiography? / 대한뇌혈관외과학회지

OBJECTIVE: Ruptured intracranial aneurysms usually present as a subarachnoid hemorrhage (SAH), but are sometimes associated with intracerebral hemorrhage (ICH), intraventricular hemorrhage (IVH), or subdural hematoma (SDH). However, the presentation of a ruptured aneurysm without a SAH is quite unusual. We describe nine such cases and highlight some easily overlooked, but important clinical features. METHODS: Among 341 patients diagnosed with ruptured cerebral aneurysms during the past 4 years, 9 patients exhibited non-SAH bleeding on admission, as revealed by brain computed tomograms (CT). On these 9 patients, the characteristic features were reviewed using medical charts, emergency room notes, and radiographic findings. RESULTS: The incidence of aneurysmal rupture without SAH was 2.6%. Eight patients exhibited ICH, and among them, an IVH occurred in one patient and a SDH in two patients. The initial clinical grade was grave in 8 patients, and a favorable outcome occurred in 4 patients. All of these aneurysms arose from the anterior circulation (the circle of Willis in two patients, and distal aneurysms in seven patients). The causes of the aneurysms were spontaneous in four patients, trauma in two patients, infective endocarditis in two patients, and moyamoya syndrome with a history of craniotomy and clipping in one patient. In three patients, additional intervention was required because the initial radiographic images did not reveal a ruptured aneurysm. CONCLUSION: Ruptured aneurysms should be suspected in cases of unexplained intracranial bleeding, even if SAH is not present on the initial CT scan, because most patients exhibit a poor neurologic grade. Therefore, careful interpretation of the clinical and radiologic culprits and timely management should be provided to achieve total occlusion.