Adaptive Staged-Dose Gamma Knife Radiosurgery for the Treatment of Large Brain Metastases: Report of 40 Consecutive Cases and Analysis of Literature.

Background: Brain metastases are the most common brain tumors, being one of the most frequent neurological complications of systemic cancer and an important cause of morbidity and mortality. Stereotactic radiosurgery is efficacious and safe in the treatment of brain metastases, with good local control rates and low adverse effects rate. Large brain metastases present some issues in balancing local control and treatment-related toxicity. Objective: Demonstrating adaptive staged-dose Gamma Knife radiosurgery (ASD-GKRS) being a safe and effective treatment for large brain metastases. Materials and Methods: We retrospectively analyzed our series of patients treated with two-stage Gamma Knife radiosurgery for large brain metastases in [BLINDED], between February 2018 and May 2020. Results: Forty patients with large brain metastases underwent adaptive staged-dose Gamma Knife radiosurgery, with median prescription dose of 12 Gy and a median interval between stages of 30 days. At three-month follow-up, the survival rate was 75.0% with a local control rate of 100%. At six-month follow-up, the survival rate was 75.0% with a local control rate of 96.7%. The mean volume reduction was 21.81 cm3 (16.76-26.86; 95% CI). The difference between baseline volume and six-month follow-up volume was statistically significant. Conclusions: Adaptive staged-dose Gamma Knife radiosurgery is a safe, non-invasive and effective treatment for brain metastases, with a low rate of side effects. Large prospective trials are needed to strengthen data obtained about the effectiveness and safety of this technique in managing large brain metastases.

Complications in AVM Surgery.

In AVM surgery perioperative complications can arise and can have serious perioperative consequences. Surgically related complications in AVM treatment, in many cases, can be avoided by paying attention to details:1. Careful selection of the patient: - addressing a patient with eloquent AVM to Gamma Knife treatment - preoperative treatment with selective embolization of the accessible deep feeders - preoperative gamma knife or embolize those patient with an over-expressed venous pattern2. Meticulous coagulation of deep medullary feeders: - Using dirty coagulation - Using dry non-stick coagulation - Using micro clips - Using laser - Reaching the choroidal vessel in the ventricle when possible - Avoiding occlusive coagulation with hemostatic agents3. Check and avoiding any residual of the AVM4. Keep the patient under pressure control during postoperative periodFulfilling these steps contributes to reduce complications in this difficult surgery, leading to a safer treatment that compares favorably with natural history of brain arteriovenous malformations.

Intracranial Dural Arteriovenous Fistulas: The Sinus and Non-Sinus Concept.

INTRODUCTION: Dural arteriovenous fistulas (dAVFs) account for 10-15% of all intracranial arteriovenous lesions. Different classification strategies have been proposed in the course of the years. None of them seems to guide the treatment strategy. OBJECTIVE: We expose the experience of the vascular group at Niguarda Hospital and we propose a very practical classification method based on the location of the shunt. We divide dAVF in sinus and non-sinus in order to simplify our daily practice, as this classification method is simply based on the involvement of the sinuses. MATERIAL AND METHODS: 477 intracranial dural arteriovenous fistulas have been treated. 376 underwent endovascular treatment and 101 underwent surgical treatment. Cavernous sinus DAVFs and Galen ampulla malformations have been excluded from this series as they represent a different pathology per se. 376 dAVFs treated by endovascular approach: 180 were sinus and 179 were non-sinus. 101 dAVFs treated with surgical approach: 15 were sinus and 86 were non-sinus. DISCUSSION: Of the 477 intracranial dAVF the recorded mortality and severe disability was 3% and morbidity less than 4%. All patients underwent a postoperative DSA with nearly 100% of complete occlusion of the fistula. At a mean follow-up of 5 years in one case there was a non-sinus fistula recurrence, due to the presence of a partial clipping of "piè" of the vein. CONCLUSIONS: The sinus and non-sinus concept has guided our institution for years and has led to good clinical results. This paper intends to share this practical classification with the neurosurgical community.

Giant calcified thoracic disk herniations: ossification of PLL or autonomous entity?

BACKGROUND: Giant calcified thoracic disk herniation (GCTD) is an uncommon event, which requires surgical treatment in less than 1% of patients. GCDTs are a specific subgroup of herniated thoracic disks occupying more than 40% of the spinal canal showing calcifications associated with a certain degree of ossification. In this paper, we are reporting our whole experience in the surgical management of GCTDs through anterior approaches. We believe that they present characteristics that associate them to the circumscribed type of Ossified Posterior Longitudinal Ligament (OPLL) with a possible common pathophysiology consisting in the dural violation. METHODS: Twenty-three consecutive patients with GCDTs were managed through anterior approaches during the period 1996-2019 at the Niguarda Hospital - Milan, Italy. Clinical data, radiological features, surgical reports, histological findings, and outcomes were reviewed. RESULTS: There was no mortality, whereas permanent morbidity consisted of 1 cases of worsened paraparesis due to accidental spinal cord contusion. One patient required reoperation to repair a postoperative cerebrospinal fluid (CSF) leakage. All patients underwent postoperative MRI which showed excellent decompression of cord and dural sac in all cases. Histological study of en-bloc removed GCTD showed typical calcification patterns of the PLL. CONCLUSIONS: GCDTs may be assimilated to the so-called "circumscribed type" of OPLL. The GCDTs may show the same radiological CT and MRI pattern of OPLL. The anterior accesses now represent the standard of care for GCTDs. The use of operative microscope and intraoperative monitoring is mandatory. The risk of CSF leakage can be markedly reduced by meticulous reconstruction of the dura and the placement of spinal drainage. Adequate exposition may sometimes require one or two levels of corpectomy with consequent vertebral body reconstruction and fixation of anterior column of the spine.

Contemporary tools in arteriovenous malformations surgery.

Arteriovenous malformations (AVMs) are rare entities and therefore considered the main challenge for a neurosurgeon. Since the publication of the ARUBA study, one of the most popular debate regards the actual surgical indication for unruptured AVMs. Our group recently published a multicenter review of more than 500 cases underlying the important role of surgery. Over the last few decades, the expanding technologies used in the treatment of AVMs have shown an ongoing improvement overcoming some of the existing difficulties and shortcomings. In this paper, we reviewed the present literature to illustrate the main contemporary tools that, in our opinion, are crucial to obtain the best surgical and clinical outcome. Indocyanin green is nowadays considered a gold standard to identify arterial feeders, draining veins, and to detect any eventual residual. The use of non-stick, bipolar, 2-mm blade microclips, and thulium laser allows to obtain a better bleeding control and nidus removal. The development of the intraoperative ultrasound with neuronavigation, angiosonography, and color-Doppler improves the accuracy of AVM resection. Moreover, improvements have been developed with the use of intraoperative micro-Dopplers combined with flow measurements, which consent to verify the gradual reduction of flow through draining veins. The possibility to perform functional preoperative studies and intraoperative monitoring can be considered as an essential point in the decision making in eloquent or near-eloquent AVMs. Furthermore, the hybrid operating room represents the best expression of an excellent neurovascular team where the use of the intraoperative angiography allows neurosurgeons and neurointerventional radiologists to work at the same time in a combined approach to achieve the best surgical removal.