Is It Time for a Paradigm Shift in the Surgical Management of Trigeminal Schwannomas? Evaluating the Role of the Transorbital Approach: An Anatomo-Clinical Study and Systematic Literature Review.

BACKGROUND: Endoscopic transorbital approach emerged in recent years as an effective, minimally invasive route to access Meckel's cave area. Several case series proved its effectiveness in the surgical treatment of trigeminal schwannomas. This route provides the advantages of a minimally invasive approach associated with low morbidity rates. In this anatomo-clinical study we illustrate the usefulness of the superior eyelid transorbital approach for the surgical treatment of trigeminal schwannoma guiding the clinical applicability of the anatomical findings into real surgical practice. METHODS: Superior eyelid transorbital endoscopic approach was performed on 8 cadaveric specimens, and the surgical results were confirmed in a retrospective review of all the surgical cases of transorbital surgery performed by the senior authors providing an illustrative case. Finally, we performed a literature review of all the case series of trigeminal schwannomas operated through an endoscopic transorbital approach. RESULTS: Stepwise dissection was divided in 3 phases: skin, endo-orbital, and endocranial. The illustrative case provided demonstrate gross total resection of a cavernous sinus type trigeminal schwannomas treated through this route. Literature review revealed 68 cases of trigeminal schwannomas that were successfully treated using the transorbital approach. CONCLUSIONS: The endoscopic transorbital approach may offer a valuable alternative for the surgical treatment of trigeminal schwannomas. This technique provides a minimally invasive, direct and natural "interdural" route to the lateral wall of the cavernous sinus and Meckel's cave.

Fluorescein-assisted stereotactic needle biopsy of brain tumors: a single-center experience and systematic review.

Over the last years, fluorescence-based technology has begun an emergent intraoperative method for diagnostic confirmation of brain tumor tissue in stereotactic needle biopsy. However, the actual level of evidence is quite low, especially about fluorescein sodium (FL) application. This method needs to be further validated and better analyzed about its impact in clinical practice. Retrospective analysis of 11 cases with contrast-enhancing brain tumors, underwent awake stereotactic needle biopsy with intraoperative FL assistance (group 1), was verified under the operative microscope filter. This group was matched with a control group of 18 patients (group 2). In addition, a systematic literature review was performed in PubMed/Medline database according to PRISMA statement. All studies concerning FL or 5-ALA application in stereotactic biopsy as intraoperative confirmation of brain tumor tissue were included. The primary endpoint was the evaluation of diagnostic accuracy. In group 1, all fluorescent specimens were diagnostic. The number of samplings was the useful minimum and non-use of intraoperative neuropathological examination allowed to significantly reduce procedure time (42.09 vs 69.72 min of group 2). No complications occurred, and the average hospitalization time after procedure was 1.09 days (vs 2.33 of group 2). Literature analysis supports the usefulness of photodiagnosis and its high diagnostic yield especially at the core of high-grade/contrast-enhancing tumors. FL assistance during stereotactic biopsy of contrast-enhancing brain tumors may give a real-time confirmation of tumor tissue, maximizing the diagnostic yield, and reducing time of procedure, morbidity, and hospitalization.

Palatal Position of Patient Tracker for Magnetic Neuronavigation System: Technical Note.

OBJECTIVE: Recently, the neuronavigation system (NS) has become an essential intraoperative tool for many neurosurgical procedures, allowing for precise lesion localization. It is particularly important to avoid errors during the navigation process. Here we report a novel technique using palatal positioning of the patient tracker to ensure optimal accuracy during magnetic navigation in various neurosurgical procedures. METHODS: This retrospective study included a total of 34 patients treated in our institution between June 2017 and January 2018. The patients were split into 2 groups who underwent surgery under general anesthesia: a microscopic transcranial group and an endoscopic endonasal group. Preoperative and postoperative navigation accuracy was assessed by 2 neurosurgeons. RESULTS: After our surgical planning navigation protocol was applied, both transcranial and endonasal procedures were successfully performed under navigation guidance in all but 1 patient. There were no intraoperative or postoperative complications related to the tracker mounted under the hard palate. In 33 cases a maximal tracking view and optimal navigation accuracy was achieved, for a success rate of 97%. CONCLUSIONS: The positioning of the patient tracker under the hard palate proved safe, accurate, and feasible in 97% of our patients. In our case series, it met the main goal of avoiding device displacement without a sense of invasiveness and postoperative patient discomfort.

Cerebrovascular disorders and Fahr's disease: Report of two cases and literature review.

Fahr's disease is a rare idiopathic nosological entity, characterized by calcification of the basal ganglia and dentate nuclei of the cerebellum. Sometimes it may be associated to other diseases like cerebrovascular disorders. However, this link remains unclear and it needs to be further validated. We report two cases of patients with cerebrovascular disorders and Fahr's disease. In the first case, a 69-years-old woman with right internal capsule-basal ganglia haemorrhage. In the second case, a 72-years-old woman with ischemic stroke and pericallosal artery aneurysm. The physiopathology is discussed and concerning literature is reviewed.

Frontolateral Approach Combined with Endoscopic Endonasal Extradural Posterior Clinoidectomy to the Upper Clival Region: Anatomic and Feasibility Study.

BACKGROUND: Surgical management of lesions located in the upper clival region is challenging. Complex open transcranial approaches have been used to reach surgical targets in these areas. The frontotemporozygomatic approach combined with an intradural posterior clinoidectomy has been proposed as the most reliable route to manage such lesions. We investigated combining a minimally invasive endoscopic endonasal extradural posterior clinoidectomy (EPC) with a standard frontolateral approach to expand the working area within the upper clival region. METHODS: Investigators dissected 10 human cadaveric heads at the Laboratory of Surgical NeuroAnatomy of the University of Barcelona. The heads were positioned to simulate a supine position, enabling the simultaneous use of both endonasal and frontolateral routes. The dissections were divided into 3 steps-standard frontolateral approach, EPC, and re-evaluation of the frontolateral route-aiming to compare the surgical exposure before and after EPC. RESULTS: After EPC, through the frontolateral pathway it was possible to improve visualization and working angles to the interpeduncular fossa and retrosellar and upper clival regions. Increase in extension of the carotid-oculomotor window was 7 mm and 10 mm before and after the posterior clinoidectomy, respectively. CONCLUSIONS: EPC provided extra working space for the frontolateral approach to the upper clival area with 42.8% expansion of the carotid-oculomotor triangle. Surgical series are needed to demonstrate clinical advantages and disadvantages of this novel combined approach.

Fluorescein-Guided Surgery for High-Grade Glioma Resection: An Intraoperative "Contrast-Enhancer".

BACKGROUND: Fluorescein sodium salt is widely used in medicine as fluorescein isothiocyanate and commonly named fluorescein (FL). This fluorophore has been used as a fluorescent tracer for many applications, especially in ophthalmic surgery. It was initially used in neuro-oncology in 1948 to control tumor resection margins. After a transient disuse, it has recently had a second spring with the development of dedicated filters for operating microscopes, although it is still under evaluation in clinical use. The aim of this study is to contribute to the investigation according to which FL-guided surgery for high-grade glioma (HGG) is related to better rates of gross total resection (GTR) and so to a better outcome. METHODS: We retrospectively analyzed 23 cases of patients with new diagnosis of HGG, operated on in our unit by intraoperative FL use with a filter system directly integrated into an operative microscope (group 1). Fluorescence was compared with histology by biopsies carried out both in the fluorescent areas and in the periphery of fluorescent areas. Group 1 was matched with a control group of 25 patients with HGG operated on in our unit during the last 2 years without FL guidance (group 2). RESULTS: No side effects occurred related to FL. Histology and intraoperative neuronavigation showed strong correspondence with fluorescent and nonfluorescent areas. GTR rate was significantly higher in group 1 (82.6%) than in group 2 (52%). CONCLUSIONS: Intraoperative fluorescein-guided surgery showed safety and feasibility. Our and other studies suggest an improvement of GTR rate in HGG than nonuse.

The use of a three-dimensional endoscope for different skull base tumors: results of a preliminary extended endonasal surgical series.

BACKGROUND: The evolution of skull base surgery over the past decade has been influenced by advancement in visualization technology. Recently, as a result of such improvements, three-dimensional (3-D) scopes have been widely used during endoscopic endonasal approaches. In the present study, we describe the use of 3-D stereoscopic endoscope for the treatment of a variety of skull base lesions. METHODS: From January 2010 to June 2015, a 3-D endoscopic endonasal approach (4 and 4.9 mm, 0°, and 30° rigid endoscopes) was performed in 70 patients with the following lesions: 42 large extrasellar pituitary macroadenomas, seven tuberculum sellae meningiomas, seven clivus chordomas, five craniopharyngiomas, three fibrous dysplasia of the clivus, three sinonasal malignancies, one orbital lymphangioma, one trigeminal neurinoma, one primary suprasellar lymphoma. RESULTS: Total tumor removal was obtained in 50 patients (71.4 %) while in 14 (20 %), subtotal removal was possible in six (8.6 %) only partial removal was achieved. Overall complications included diabetes insipidus in eight patients (11.4 %), hypopituitarism in seven patients (10 %), CSF leak in five patients (7.1 %), cranial nerve injury in two patients (2.8 %), panhypopituitarism in two patients (2.8 %), meningitis in one (1.4 %) and one postoperative central retinal artery occlusion (1.4 %). There was no mortality in the series. The mean follow-up time was 39 months (range, 6-72 months). CONCLUSIONS: In our experience, the 3-D endoscope represents a critical development in visualization, thus enabling improved hand-eye coordination and depth perception, which are mandatory for the management of complex intradural neurovascular structures during tumor removal surgery.

Use of a collagen biomatrix (TissuDura) for dura repair: a long-term neuroradiological and neuropathological evaluation.

PURPOSE: The aim of this study was to evaluate the clinical, neuroradiological, and neuropathological outcomes of patients treated with equine collagen foil (TissuDura) as a dura mater substitute during cranial and spinal neurosurgical procedures. MATERIALS AND METHODS: All patients treated at the Department of Neurosurgery of the Second University of Naples with TissuDura between 2005 and 2009 were included. Dural reconstruction was performed using TissuDura, overlaid 1 cm over the dural defect with additional fixation using fibrin glue. No surgical sutures were used. Patients underwent postoperative contrast-enhanced magnetic resonance scans at 1 week, 1 month, and 1 year after surgery to detect any cerebrospinal fluid (CSF) leaks, infections, inflammations, or CSF circulation in the surgical region. RESULTS: Dural reconstruction was performed in 74 patients, including 50 patients with tumors, two with C2 neurinoma, two with acoustic neurinoma, six with Chiari I malformation, two with severe head injury, and 12 requiring spinal surgery. Clinical and neuroradiological findings were normal and no signs of graft rejection or CSF leaks at postoperative follow-up were observed. In two cases of atypical meningioma, re-operation of the dural reconstruction was performed after 1 year. No adherences between brain and neodura were detected, and histopathological investigations demonstrated dural regeneration. CONCLUSIONS: Following dural reconstructions with TissuDura without surgical sutures, no local toxicity or complications were observed for up to 1 year. TissuDura demonstrated elasticity, non-reactivity, and good adaptability. The overlay technique using fibrin glue was simple and fast. Future studies and longer follow-up are needed to confirm the efficacy of TissuDura.

Cranial reconstruction using bioabsorbable calcified triglyceride bone cement.

BACKGROUND: We report our experience on 6 cases of cranial reconstruction using bioabsorbable calcified triglyceride KRYPTONITE Bone Cement (Doctors Research Group). METHODS: Six patients underwent cranial reconstruction during the surgical removal of a supratentorial tumor between September 2008 and November 2009 at our department. In 5 patients, we performed the cranial reconstruction using KRYPTONITE Bone Cement and cranial fixations; in the remaining patient, we avoided cranial fixation systems or other bone sutures to obtain good aesthetic results in the frontal supraorbital region. Preoperatively and 7 days and 12 months after surgery, patients were assessed using craniocerebral magnetic resonance imaging and computed tomography (CT). RESULTS: We observed that this bone cement was an injectable liquid for up to 8 minutes after mixing, it became adhesive at 8 to 15 minutes, and it was then shaped for use. Brain and dural reconstructions were not protected when this bone cement was being poured into the craniotomy site because of the minimal exothermal reaction. After 8 minutes, additional expansion is limited to 10%; therefore, we took heightened awareness of the amount of cement needed to fill the bone defect. In all patients, postoperative craniocerebral CT scanning, at 7 days, showed perfect alignment of the craniotomical bone and optimal filling of bone defects. No complications occurred, and aesthetic result was good. Twelve months after surgery, craniocerebral CT scanning showed bioabsorbability and osteoconductivity of this cement. CONCLUSIONS: KRYPTONITE Bone Cement is a nonthermal conducting, radiopaque, nonmagnetic, lightweight, simple to prepare, and easily applicable and molded material. Moreover, it has adhesive, bioabsorbable, and osteoconductive properties. To our knowledge, we present the first case of cranial reconstruction using this cement without cranial fixation systems.