Oriela Rustemi

Predictive value of intraoperative 5-aminolevulinic acid–induced fluorescence for detecting bone invasion in meningioma surgery

OBJECT Bone invasion is a major concern in meningioma surgery, since it is predictive of the recurrence of cranial involvement, morbidity, and mortality. Bone invasion has been reported in 20%-68% of studies with histopathologically confirmed data. Unfortunately, radical resection of bone invasion remains challenging. The aim of this study was to assess the role of 5-aminolevulinic acid (5-ALA) fluorescence in guiding the resection of bone-invading meningiomas. To this purpose, the sensitivity, specificity, and positive and negative predictive values of 5-ALA in detecting meningioma bone invasion were evaluated. METHODS Data from 12 patients affected by bone-invading meningiomas (7 with skull base and 5 with convexity meningiomas) who had undergone surgery with the assistance of 5-ALA fluorescence and neuronavigation between July 2012 and March 2013 at the Department of Neurosurgery of Padua were retrospectively analyzed. To evaluate the sensitivity and specificity of 5-ALA fluorescence in detecting meningioma tissue, a pathologist analyzed 98 surgical bone samples under blue light, according to different fluorescence patterns. Magnetic resonance images and CT scans were obtained pre- and postoperatively to determine the extent of bone invasion resection. RESULTS The rate of 5-ALA-induced fluorescence of both tumor and bone invasion was 100%. Based on the pathological examination of bone specimens, 5-ALA presented a sensitivity of 89.06% (95% CI 81.41%-96.71%) and a specificity of 100% in detecting meningioma bone invasion, while the positive and negative predictive values were 100% and 82.93% (95% CI 71.41%-94.45%), respectively. At the postoperative stage, MRI did not detect cases of meningioma bone invasion, whereas CT scans revealed residual hyperostosis in 2 cases. CONCLUSIONS In summary, 5-ALA fluorescence represents a suitable and reliable technique for identifying and removing bone infiltration by meningiomas. However, further studies are needed to prove the clinical consequences of this promising technique in a larger population.

Acute surgical removal of low-grade (Spetzler-Martin I-II) bleeding arteriovenous malformations.

BACKGROUND Early surgical removal of cerebral AVMs is a relatively infrequent therapeutic option when dealing with a cerebral hemorrhage caused by AVM rupture: even in the case of low-grade AVMs, delayed treatment is, if possible, preferred because it is considered safer for patients and more comfortable for surgeons. To assess whether acute surgery may be a safe and effective management, we conducted a retrospective analysis of our early surgery strategy for ruptured low-grade AVMs. METHODS We reviewed 27 patients with SM grade I-II AVM treated during 2004 to 2008 in the acute stage of bleeding (within the first 6 days after bleed). All patients showed a cerebral AVM on DSA at admission, and surgical removal was controlled by postoperative angiography. Neurological outcomes were assessed with GOS. The average length of follow-up was 22 months (48-3 months). RESULTS Before surgery, 16 (59%) patients showed a GCS of 8 or less, 2 of them presenting an acute rebleeding after first hemorrhage. All patients underwent radical AVM surgical removal and hematoma evacuation in a single-stage procedure. Most patients (78%) were operated within the first day of hemorrhage. A favorable functional outcome (GOS: good recovery or moderate disability) was observed in 23 patients (85%). Mortality was 7.4%. Outcome was not significantly correlated with GCS at presentation and with presence of preoperative anisocoria. CONCLUSIONS Early surgery for grade I-II AVMs is a safe and definitive treatment, achieving both immediate cerebral decompression and patient protection against rebleeding, reducing time of hospital stay and allowing a more rapid rehabilitative course whenever necessary.

Microsurgical clipping of intracranial aneurysms assisted by green indocyanine videoangiography (ICGV) and ultrasonic perivascular microflow probe measurement.

OBJECTIVES The purpose of this work is to assess the surgical and clinical outcome of intracranial aneurysm clipping performed combining the assistance of green indocyanine videoangiography (ICGV) and ultrasonic perivascular microflow probe. PATIENTS AND METHODS Data from patients affected with intracranial aneurysms who underwent microsurgical clipping assisted by both techniques between May 2012 and April 2013 were retrospectively evaluated. RESULTS 26 patients with 34 aneurysms (25 unruptured) were enrolled. In a total of 11 aneurysms (32%), the vascular clip needed repositioning, since either the post-clipping microprobe assessment detected a significant flow reduction of the explored vessels (8 cases, 23%) or ICGV identified a residual non-obliterated aneurysm (3 cases, 9%). A second clip repositioning was required in 3 cases (9%) because of dome remnant showed with ICGV. In all cases, final microprobe and ICGV assessments showed a complete exclusion of the aneurysm, without evidence of vascular flow impairment. Postoperatively, 1 patient (3%) presented a residual neck aneurysm. No permanent morbidity was reported. CONCLUSION With the limits of our small case series, our results testify that the presented approach may provide high exclusion rate in the treatment of cerebral aneurysm with very low morbidity in selected patients.

The "squeezing maneuver" in microsurgical clipping of intracranial aneurysms assisted by indocyanine green videoangiography.

BACKGROUND: Indocyanine green videoangiography (ICGV) is becoming routine in intracranial aneurysm surgery to assess intraoperatively both sac obliteration and vessel patency after clipping. However, ICGV-derived data have been reported to be misleading at times. We recently noted that a simple intraoperative maneuver, the “squeezing maneuver,” allows the detection of deceptive ICGV data on aneurysm exclusion and allows potential clip repositioning. The squeezing maneuver is based on a gentle pinch of the dome of a clipped aneurysm when ICGV documents its apparent exclusion. OBJECTIVE: To present the surgical findings and the clinical outcome of this squeezing maneuver. METHODS: Data from 23 consecutive patients affected by intracranial aneurysms who underwent the squeezing maneuver were analyzed retrospectively. The clip was repositioned in all cases when the dyeing of the sac was visualized after the maneuver. RESULTS: In 22% of patients, after an initial ICGV showing the aneurysm exclusion after clipping, the squeezing maneuver caused the prompt dyeing of the sac; in all cases, the clip was consequently repositioned. A calcification/atheroma of the wall/neck was predictive of a positive maneuver (P = .001). The aneurysm exclusion rate at postoperative radiological findings was 100%. CONCLUSION: With the limits of our small series, the squeezing maneuver appears helpful in the intraoperative detection of misleading ICGV data, mostly when dealing with aneurysms with atheromatic and calcified walls. ABBREVIATIONS: DSA, digital subtraction angiography ICG, indocyanine green ICGV, indocyanine green videoangiography

Transdural indocyanine green video-angiography of vascular malformations

BackgroundThe role of indocyanine green video-angiography (ICG-VA) in the surgical resection of vascular malformations has been largely described; conversely, the utility of ICG-VA before dural opening (transdural ICG-VA) in this situation remains unclear. The aim of this study is to present the application of transdural ICG-VA in a consecutive series of patients in order to explore the potential provided by a transdural visualisation of vascular malformations.MethodWe retrospectively analysed the application of intra-operative ICG-VA before dural opening in 15 consecutive patients who underwent surgical resection of vascular malformations. The cases included 12 cerebral arterio-venous malformations (AVMs), 2 cerebral dural arterio-venous fistulas (dAVFs) and 1 spinal arterio-venous fistula (AVF).ResultsICG-VA before dural opening allowed the visualisation of the site and extension of the malformation in 13 out of 15 cases, whilst arterial feeders and venous drainages were identified in 9 out of 15 cases. In two patients with dAVF, the point of fistula could be transdurally identified through ICG-VA. In 14% of cases, the size of bone flap designed on neuronavigation data was then modified according to transdural ICG-VA findings.ConclusionsTransdural ICG-VA proved an efficient tool that allows optimising the exposure of the malformation, performing a safe dural opening and identifying dural vascular connections of the lesion.

Open Transcranial Resection of Small (<35 mm) Meningiomas of the Anterior Midline Skull Base in Current Microsurgical Practice

OBJECTIVE Despite technical surgical advance, the ultimate management of midline anterior skull base meningiomas remains to be defined. Open transcranial surgery is usually the first treatment option for large meningiomas, while less invasive techniques such as endoscopic surgery or radiosurgery might represent an alternative to open microsurgery for smaller lesions. The aim of our study is to investigate the outcome of open transcranial microsurgery in the resection of small (<35 mm) meningiomas of the midline anterior cranial base. METHODS Clinical and surgical data from 43 patients affected by small midline anterior skull base meningiomas operated via an open transcranial approach were retrospectively reviewed. RESULTS The tumor diameter on its major axis ranged from 12 to 35 mm, with a mean diameter of 28 mm. Gross total resection (Simpson grades I-II) was achieved in 100% of cases through a pterional approach. Postoperative overall morbidity was 9%. It was 3% among patients <70 years. No mortality was reported. Postoperative visual outcome was significantly associated with preoperative visual performance (P = 0.02), but not with preoperative optic nerve compression as detected by magnetic resonance imaging (P = 0.116). Age >70 years was associated with postoperative visual impairment, although not significantly (P = 0.06). Visual function was preserved or improved in 95% of cases, in 100% of patients <70 years, and in 71% of patients with preoperative visual impairment. CONCLUSIONS In our experience, open transcranial surgery proved safe and effective for midline anterior skull base meningiomas smaller than 35 mm in all patients <70 years and in patients >70 years without preoperative visual deficit. Our data are consistent with the literature. Conversely, the standard of treatment for the subgroup of patients >70 years with preoperative visual deficit has not yet been defined. This specific subgroup of patients offers a topic for further investigation.

Original ArticleOpen Transcranial Resection of Small (<35 mm) Meningiomas of the Anterior Midline Skull Base in Current Microsurgical Practice

OBJECTIVE Despite technical surgical advance, the ultimate management of midline anterior skull base meningiomas remains to be defined. Open transcranial surgery is usually the first treatment option for large meningiomas, while less invasive techniques such as endoscopic surgery or radiosurgery might represent an alternative to open microsurgery for smaller lesions. The aim of our study is to investigate the outcome of open transcranial microsurgery in the resection of small (<35 mm) meningiomas of the midline anterior cranial base. METHODS Clinical and surgical data from 43 patients affected by small midline anterior skull base meningiomas operated via an open transcranial approach were retrospectively reviewed. RESULTS The tumor diameter on its major axis ranged from 12 to 35 mm, with a mean diameter of 28 mm. Gross total resection (Simpson grades I-II) was achieved in 100% of cases through a pterional approach. Postoperative overall morbidity was 9%. It was 3% among patients <70 years. No mortality was reported. Postoperative visual outcome was significantly associated with preoperative visual performance (P = 0.02), but not with preoperative optic nerve compression as detected by magnetic resonance imaging (P = 0.116). Age >70 years was associated with postoperative visual impairment, although not significantly (P = 0.06). Visual function was preserved or improved in 95% of cases, in 100% of patients <70 years, and in 71% of patients with preoperative visual impairment. CONCLUSIONS In our experience, open transcranial surgery proved safe and effective for midline anterior skull base meningiomas smaller than 35 mm in all patients <70 years and in patients >70 years without preoperative visual deficit. Our data are consistent with the literature. Conversely, the standard of treatment for the subgroup of patients >70 years with preoperative visual deficit has not yet been defined. This specific subgroup of patients offers a topic for further investigation.

Intraoperative flow measurement by microflow probe during surgery for brain arteriovenous malformations.

BACKGROUND: Intraoperative quantitative flow measurement by a microvascular ultrasonic flow probe is an established methodology in aneurysm surgery. OBJECTIVE: To test the present flow measurement procedure in brain arteriovenous malformation (AVM) surgery. METHODS: Data from 25 patients with brain AVMs who consecutively underwent microsurgical resection with the assistance of flow measurement by a microflow probe were retrospectively analyzed. Flowmetry was performed on arterial feeders, potentially transit arteries, and venous drainage of AVM in different phases of resection. RESULTS: A quantitative flow measurement was performed 203 times on 92 vessels. Flowmetry was able to define the flow direction of AVM vessels in all cases, thereby discriminating between arterial feeders and venous drainages, both superficially and deeply located. During AVM dissection, flowmetry identified a transit artery in 12% of cases by detecting a flow drop between 2 points of the same vessel. At the final stage of resection, a residual nidus, potentially missed at surgical dissection, was detected when the flow value of venous drainage was greater than 4 mL/min (20% of patients). Pre-resection microflow probe measurements were concordant with indocyanine green videoangiography data on AVM angioarchitecture in all cases. No microflow probe–induced AVM vessel injury was reported. Complete AVM resection was achieved in all cases with a low morbidity (modified Rankin Scale score ⩽1). CONCLUSION: Multistage intraoperative quantitative flow measurement proved to be a feasible, safe, repeatable, and reliable methodology to assist surgery in different phases of AVM resection. Further studies are needed to assess the impact of this approach on AVM patient outcomes. ABBREVIATIONS: AVM, arteriovenous malformation bAVM, brain arteriovenous malformation DSA, digital subtraction angiography ICG-VA, indocyanine green videoangiography mRS, modified Rankin Scale SM, Spetzler Martin

The suboccipital midline approach to foramen magnum meningiomas

BackgroundAnterior and anterolateral meningiomas of the foramen magnum (FM) can be resected either through extensive skull base approaches or through the classical suboccipital midline approach with limited bone removal.MethodThis paper describes the suboccipital midline approach focusing on some peculiar technical features that serve to achieve the necessary space for safe resection of these challenging tumors.ConclusionsIn our experience, by adopting appropriate strategies to gain space (some of them natural, others acquired) the suboccipital midline approach can achieve the safe resection of anterior and anterolateral FM meningiomas in the majority of cases.

Approaching a brainstem high-grade glioma (HGG) with the assistance of 5-aminolevulinic acid (5-ALA) technology: a new strategy for an old surgical challenge

Brainstem high-grade glioma (HGG) surgery remains challenging despite the assistance of neurophysiological monitoring, and presents remarkable morbidity (6.7–27.6 %) and mortality (1.3–16 %) rates [1]. Although the role of 5-aminolevulinic acid (5-ALA) assistance in high-grade gliomas surgery is well established, its application in the resection of brainstem gliomas has not yet been investigated. We report a case of a brainstem highgrade glioma we recently resected with the assistance of 5-ALA fluorescence and neurophysiological monitoring. The choice of intra-operative 5-ALA fluorescence assistance depended on the pre-operative radiological findings, showing a contrast enhancing tumor located at the lower brainstem (Fig. 1a). Informed consent was obtained. Three hours before induction of anesthesia, a dose of 20 mg/kg of 5-ALA (Medac GmbH, Hamburg, Germany) was administered orally. A neurosurgical microscope equipped with Blue 400 technology (Carl Zeiss, OPMI Pentero, Blue 400, Meditec, Germany) enabled the surgeon to switch from white xenon illumination to violet–blue excitation light during microneurosurgery. Our surgical attitude entailed the use of 5-ALA fluorescence to guide surgical resection until a motor (MEP) or somatosensory evoked potential (SSEP) amplitude decrease was recorded, or the presence of a lower cranial nerve nucleus/fascicle was detected by intra-operative electro-stimulation at tumor boundaries. Intra-operatively (Fig. 1b–e), the exofitic component of the lesion was clearly visible between the cerebellar tonsils, just before arachnoidal opening. The lesion appeared fluorescent under violet–blue light, enabling a tailored arachnoidal opening and assisting the dissection of the tumor from healthy tissues. The areas of intense pink enhancement, being identified as clearly pathological, were removed and sent to pathologist. The tumor was further removed under blue light using an ultrasonic dissector and with the assistance of neurophysiological monitoring. Although the ependymal tissue of the fourth ventricle showed a faint and uniform fluorescence, this was still considerably distinct from the bright fluorescence of the tumor. Fourth ventricle tela chorioidea and choroidal plexus were not fluorescent under blue light. Tumor resection was stopped after the complete resection of fluorescent tissue. The post-operative images showed no contrast enhancing tumor at MRI scans with gadolinium (Fig. 1f). The patient presented a post-operative dysphagia that completely recovered within 2 weeks. 5-ALA is a well-established tool in the current surgical management of high-grade glioma; it has been proved reliable and effective in both detecting tumor tissue and maximizing the extent of resection of supratentorial gliomas [2]. However, to our knowledge, to date there are no reports of the application of 5-ALA in the resection of brainstem high-grade glioma. We think that from the present case three main considerations can arise. Firstly, in our experience 5-ALA fluorescence was effective in assisting tumor resection. Indeed, it enabled early identification of tumor on brainstem surface thus guiding the correct surgical resection strategy. The sharp dissection between pathological and healthy tissue was helpful in guiding the successive tumor removal in this critical location. As far as the fluorescence pattern of tumor is concerned, the brainstem high-grade glioma showed the same fluorescence features as supratentorial high-grade gliomas. This is an interesting issue if we A. Della Puppa (&) O. Rustemi G. Gioffrè R. Scienza Department of Neurosurgery, Padua University Hospital, Azienda Ospedaliera di Padova, via Giustiniani, 2, 35128 Padua, Italy e-mail: alessandro.dellapuppa@sanita.padova.it