Microsurgery of residual or recurrent complex intracranial aneurysms after coil embolization - a quest for the ultimate therapy.

The long-term stability of coil embolization (CE) of complex intracranial aneurysms (CIAs) is fraught with high rates of recanalization. Surgery of precoiled CIAs, however, deviates from a common straightforward procedure, demanding sophisticated strategies. To shed light on the scope and limitations of microsurgical re-treatment, we present our experiences with precoiled CIAs. We retrospectively analysed a consecutive series of 12 patients with precoiled CIAs treated microsurgically over a 5-year period, and provide a critical juxtaposition with the literature. Five aneurysms were located in the posterior circulation, 8 were large-giant sized, 5 were calcified/thrombosed. One presented as a dissecting-fusiform aneurysm, 9 ranked among wide neck aneurysms. Eight lesions were excluded by neck clipping (5 necessitating coil extraction); 1 requiring adjunct CE. The dissecting-fusiform aneurysm was resected with reconstruction of the parent artery using a radial artery graft. Three lesions were treated with flow alteration (parent artery occlusion under bypass protection). Mean interval coiling-surgery was 4.6 years (range 0.5-12 years). Overall, 10 aneurysms were successfully excluded; 2 lesions treated with flow alteration displayed partial thrombosis, progressing over time. Outcome was good in 8 and poor in 4 patients (2 experiencing delayed neurological morbidity), and mean follow-up was 24.3 months. No mortality was encountered. Microsurgery as a last resort for precoiled CIAs can provide-in a majority of cases-a definitive therapy with good outcome. Since repeat coiling increases the complexity of later surgical treatment, we recommend for this subgroup of aneurysms a critical evaluation of CE as an option for re-treatment.

The sellar and suprasellar region: A "hideaway" of rare lesions. Clinical aspects, imaging findings, surgical outcome and comparative analysis.

OBJECTIVE: Apart from the "common" lesions (e.g. pituitary adenomas, Rathke's cleft cysts, meningiomas and craniopharyngiomas), there is a plethora of rare tumors or tumor-mimicking lesions in the sellar and suprasellar region (SSR). Due to a lack of characteristic imaging features, there is a dilemma in distinguishing these rare lesions from the more "common" ones preoperatively. Consequently, both diagnosis and definition of surgical goals, as well as further treatment strategies continue to be challenging for all attending physicians. To replenish the scarce data on this issue, we analysed all patients with infrequent non-adenomatous pathologies in the SSR treated in our clinic, providing a database for further studies. METHODS: A retrospective study was performed including 223 patients who were operated on lesions within the SSR at the Department of Neurosurgery, Hannover Medical School, between 2006 and 2014. The patients' charts were analysed with regard to the results of pre-/postoperative endocrinological and neuroophthalmological examinations. Preoperative T2WI were analysed with special focus on distinct growth patterns within four quadrants constituting the (supra-)sellar region. In this way, a comparative analysis between the diverse lesions regarding their clinical features, resectability and the final outcome was possible. RESULTS: After exclusion of cases with "common" lesions, a collective of 20 patients with rare lesions within the SSR was obtained. The histopathological diagnosis revealed xanthogranulomas (n=6), metastatic tumors (n=5), colloid/epidermal cysts (n=3), pilocytic astrocytomas (n=2), and one case each of gangliocytoma, lymphocytic hypophysitis or concomitant germ cell tumor/rhabdomyosarcoma. In comparison to non-infiltrative lesions, those of infiltrative nature caused more frequently diplopia and deterioration of visual acuity (4 cases; p<0,05) that were less prone to improve postoperatively. Regarding growth pattern, metastatic tumors demonstrated main growth within the third quadrant with destructive remodelling of the dorsum sellae (p<0,05). While patients harbouring large lesions (>20mm) showed a significantly worse outcome regarding hormonal deficits (p=0,0313), the overall prognosis was heavily linked to the histopathological diagnosis. CONCLUSION: The correlation of the subtle radiological findings demonstrated with the specific clinical features may facilitate the differential diagnosis of rare lesions of the SSR and aid in establishing an interdisciplinary diagnostic and therapeutic procedure for these lesions.

Petroclival meningiomas: Magnetic resonance imaging factors predict tumor resectability and clinical outcome.

OBJECTIVE: Despite advances in skull base surgery, surgical removal of petroclival meningiomas (PCM) still poses a considerable neurosurgical challenge with regard to postoperative morbidity and the patients' long-term outcome. Knowledge of imaging features for PCM that might help to predict common risk factors encountered with tumor resection preoperatively is limited. The aim of this study was to clarify whether MRI features of PCM might predict tumor resectability and clinical outcome. METHODS: A retrospective analysis of 18 cases of PCM treated surgically in our department between 2007 and 2013 was performed. Following radiological tumor features were compared to the extent of tumor resection and the patients' outcome: a) tumor diameter, b) calcification, c) tumor margin towards the brainstem, d) presence of an arachnoidal cleavage plane, e) brainstem edema, f) brainstem compression and g) tumor signal intensity on T2WI. RESULTS: There was an excellent correlation between tumor resectability and preoperative findings with regard to the presence or absence of an arachnoidal cleavage plane and an irregular tumor margin towards the brainstem. Additionally, the presence of brainstem edema was significantly related to surgical morbidity, whereas a high tumor intensity on T2WI correlated significantly with soft tumor consistency and/or vascularity encountered during surgery. CONCLUSION: As demonstrated in our series, PCM with an irregular tumor margin and absence of an arachnoidal plane towards the brainstem should be considered a high-risk group. In these cases, especially when additional brainstem edema is present, limited resection of tumor may be aspired to avoid postoperative morbidity.

Hydrocephalus associated with vestibular schwannomas: management options and factors predicting the outcome.

OBJECT: The current, generally accepted optimal management for hydrocephalus related to vestibular schwannomas (VSs) is primary tumor removal, with further treatment reserved only for patients who remain symptomatic. Previous studies have shown, however, that this management can lead to an increase in surgery-related complications. In this study, the authors evaluated their experience with the treatment of such patients, with the aim of identifying the following: 1) the parameters correlating to the need for specific hydrocephalus treatment following VS surgery; and 2) patients at risk for developing hydrocephalus-related complications. METHODS: This was a retrospective study of a 400-patient series. The complication rates and outcomes following primary hydrocephalus treatment versus primary VS removal were compared. Patients undergoing primary tumor removal were further subdivided on the basis of the need for subsequent hydrocephalus treatment. The 3 categories of parameters tested for correlation with the need for such subsequent treatment as well as with heightened risk for developing complications were patient-, tumor-, and hydrocephalus-related. RESULTS: Of the entire series, 53 patients presented with hydrocephalus. Forty-eight of 53 patients underwent primary VS surgery, of whom 42 (87.5%) did not require additional hydrocephalus treatment. Of the 6 patients who did require additional hydrocephalus treatment, only 3 ultimately required a VP shunt. Factors correlating to the need of hydrocephalus treatment after VS removal were large tumor size, irregular tumor surface, and severe preoperative hydrocephalus. Patients with a longer symptom duration prior to surgery, those with polycyclic tumors, or with inhomogeneous VS, were at heightened risk for the development of CSF leaks. The general and functional outcome of surgery showed no correlation to the presence of preoperative hydrocephalus. CONCLUSIONS: Primary tumor removal is the optimum management of disease in patients with VS with associated hydrocephalus; it leads to resolution of the hydrocephalus in the majority of cases, and the outcome is similar to that of patients without hydrocephalus. Certain factors may aid in identifying patients at risk for developing persistent hydrocephalus as well as those at risk for CSF leaks.