Elena d’Avella

Indocyanine green videoangiography (ICGV)-guided surgery of parasagittal meningiomas occluding the superior sagittal sinus (SSS)

BackgroundMaximal safe resection is the goal of correct surgical treatment of parasagittal meningiomas, and it is intimately related to the venous anatomy both near and directly involved by the tumor. Indocyanine green videoangiography (ICGV) has already been advocated as an intra-operative resourceful technique in brain tumor surgery for the identification of vessels. The aim of this study was to investigate the role of ICGV in surgery of parasagittal meningiomas occluding the superior sagittal sinus (SSS).MethodIn this study, we prospectively analyzed clinical, radiological and intra-operative findings of patients affected by parasagittal meningioma occluding the SSS, who underwent ICGV assisted-surgery. Radiological diagnosis of complete SSS occlusion was pre-operatively established in all cases. ICGV was performed before dural opening, before and during tumor resection, at the end of the procedure.ResultsFive patients were included in our study. In all cases, ICGV guided dural opening, tumor resection, and venous management. The venous collateral pathway was easily identified and preserved in all cases. Radical resection was achieved in four cases. Surgery was uneventful in all cases.ConclusionsDespite the small number of patients, our study shows that ICG videoangiography could play a crucial role in guiding surgery of parasagittal meningioma occluding the SSS. Further studies are needed to define the role of this technique on functional and oncological outcome of these patients.

The endoscopic endonasal approach for cerebrospinal fluid leak repair in the elderly

INTRODUCTION Cerebrospinal fluid (CSF) rhinorrhea can lead to CNS infections, carrying significant morbidity and mortality, especially in the elderly. Endoscopic endonasal surgery is a validated technique in the repair of anterior skull base CSF leaks. The aim of this study is to assess diagnostic management, surgical technique and clinical outcome in a consecutive series of elderly patients. METHODS Patients older than 65 years treated for anterior skull base CSF leaks through endoscopic endonasal surgery between 2003 and 2014 were retrospectively reviewed. All patients underwent preoperative nasal endoscopy, laboratory and radiological assessment. In doubtful cases endoscopic exploration was performed after intrathecal fluorescein (IF) injection. Patients were discharged between 3 and 4 days after surgery, and the endoscopic follow-up ranged from 3 to 24 months. RESULTS 20 patients (age range 65-92) presented with 10 spontaneous and 10 traumatic/iatrogenic CSF leaks. In 40% of patients formal rhinoscopy and radiological assessment did not localize the CSF leak and IF injection was performed. IF enabled the identification of the skull base defect in all cases, with no adverse effects. In 11 cases the dura was repaired with fascia lata graft. All patients had successful endoscopic repair of the CSF fistula with no complications nor recurrences during follow-up. CONCLUSION Endoscopic endonasal surgery is a minimally invasive procedure for CSF leak treatment. In our experience, IF injection proved safe and efficient in detecting skull base defects not identified by preoperative imaging. Endoscopic endonasal surgery proved effective and reliable also in elderly patients, with short hospitalization times and no morbidity.

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.

Extended endoscopic endonasal transclival approach to the ventrolateral brainstem and related cisternal spaces: anatomical study

Advances in endoscopic endonasal skull base surgery have led to the development of new routes to areas beyond the midline skull base. Recently, feasible surgical corridors to the lateral skull base have been described. The aim of this study was to describe the anatomical exposure of the ventrolateral brainstem and posterior fossa through an extended endoscopic endonasal transclival transpetrosal and transcondylar approach. Six human heads were used for the dissection process. The arterial and venous systems were injected with red- and blue-colored latex, respectively. A pre- and postoperative computed tomography (CT) scan was carried out on every head. The endoscopic endonasal transclival approach was extended through an anterior petrosectomy and a medial condylectomy. A three-dimensional model of the approach was reconstructed, using a dedicated software, from the overlapping of the pre- and post-dissection CT imaging of the specimen. An extended endoscopic transclival approach allows to gain access through an extradural anterior petrosectomy and medial condylectomy to the anterolateral surface of the brainstem and the posterior fossa. Two main intradural anatomical corridors can be described: first, between the V cranial nerve in the prepontine cistern and the VII–VIII cranial nerves in the cerebellopontine and cerebellomedullary cistern; second, between the VII–VIII cranial nerves and the IX cranial nerve, in the premedullary cistern. Extending the transclival endoscopic approach by performing an extradural anterior petrosectomy and a medial condylectomy provides a safe and wide exposure of the anterolateral brainstem with feasible surgical corridors around the main neurovascular structures.

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.

Endoscopic endonasal surgery for a mesencephalic cavernoma.

Dear Editor, We illustrate the first case of a ventral midline mesencephalon cavernous malformation approached through the endoscopic endonasal route (Fig. 1a). In our opinion, the present case deserves consideration in that the localisation of the cavernous malformation, the clinical presentation consisting of an isolated third-nerve palsy without other non-ocular signs and the surgical approach used are rather unusual. Possible approaches to access cavernomas in this location include: a subfrontal route, superior to the anterior cerebral artery, Heubner’s artery and optic tract, or through the lamina terminalis; an approach through the ventricle (transcallosal, subchoroidal, transventricular approach); or between perforators coming off the M1 segment of the middle cerebral artery [2, 4, 5, 8, 9]. However, these approaches offer a limited exposure of the ventral midbrain, through a narrow corridor between the cranial nerves and vascular vital structures, besides requiring a certain amount of brain manipulation. Bricolo et al. [3] described a safe entry zone into the anterior midbrain, which allows surgical access through the more medial part of the peduncle, sparing the motor tract. In our case, entering the midbrain through this safe entry zone would still be a relatively indirect route to this cavernoma located medially to the third nerves, bringing the problem of traversing the third nerve or the necessity of its transposition. It was decided that, because of the location of the cavernoma surfacing at the midline ventral midbrain, the endoscopic transnasal transtuberculum-transplanum approach could offer the straightest and safest route to the lesion. Surgeon comfort was also considered in favour of the endoscopic endonasal skull base technique. Major issues in favour of surgery were: the pial presentation of the cavernoma surfacing at the ventral mesencephalon, thus allowing for a purely trans-lesional resection through a direct anterior approach and avoiding the need of transverse intact neural tissue; and the neurological status of the patient, which remained substantially stable during the 3 weeks after the acute onset and that the patient considered incompatible with his daily life. At surgery, once the interpeduncular fossa was entered, moving the endoscope further in the surgical field allowed for the clear visualisation of the basilar artery in the centre of the surgical field, the mammillary bodies superiorly, the cerebral peduncles and the posterior communicating arteries laterally, and the oculomotor nerves and the posterior cerebral arteries inferiorly. The haematoma overlying the cavernous malformation was encountered on the ventral surface of the midbrain (Fig. 1b). Removing a small portion of normal pituitary gland increased the working area. Pituitary gland transposition and posterior cliniodectomy could have been J. Enseñat Department of Neurosurgery, Hospital Clinic, Faculty of Medicine, Universitat de Barcelona, Barcelona, Spain

Fibrous Pituitary Macroadenomas: Predictive Role of Preoperative Radiologic Investigations for Proper Surgical Planning in a Cohort of 66 Patients

OBJECTIVE The endoscopic technique is in many cases the technique of choice for the removal of pituitary adenomas. Extended endoscopic approaches make it possible to remove lesions with suprasellar and parasellar extension and fibrous consistency. We identify some characteristics that might point to the adoption of an expanded approach in the preoperative phase. METHODS We considered 66 consecutive cases treated for pituitary macroadenomas. All patients underwent preoperative magnetic resonance imaging and computed tomography, as well as postoperative magnetic resonance imaging. From the analysis of surgical reports and preoperative radiologic investigations, we extracted data related to size, extension, morphologic characteristics, consistency, and type of approach used (sellar or expanded). The degree of removal was judged to be total, near total, subtotal, or partial. RESULTS The data showed that in some cases it is possible to assume in advance that there is a need for an expanded endoscopic approach. The features that led to an extended approach for extracapsular dissection of the lesion were the size of the tumor; an hourglass/dumbbell shape; lateral extension to the suprasellar carotid artery; Knosp degree 3 or 4; contrast enhancement heterogeneity; intratumoral hemorrhage, erosion, or discontinuity of the sellar floor; and increased sellar depth, which predicts increased thickness. CONCLUSIONS The ability to predict the consistency of pituitary adenomas allows the surgeon to design a surgical procedure tailored to the patient. This approach has advantages concerning the extent of resection and allows a radical strategy with a single surgical procedure to be pursued.