Indication: If the tumor is symptomatic or growing and the patient is of an age in which surgery is appropriate.
If the meningioma is large and has a rich vascular supply, its amenable for a pre-surgery embolization.
The resection of the meningiomas surrounding the dura is an important goal during the removal of a convexity meningioma.
da Silva et al. present the first application of sodium fluorescein (SF) as a tool for tumor and dural tail identification in convexity meningiomas.
Five frontal convexity meningiomas operated on between December 2012 and April 2013 were included. After initial dissection a dose of 1 g of the SF, 20% was injected into a peripheral vein. Tumor and dural tail were removed using the correlation between magnetic resonance imaging (MRI) findings and transoperative SF enhancement.
Simpson Grade 1 removal was obtained in three cases, grade 2 in one atypical meningioma and grade zero in one case. SF dural tail enhancement was positive in all cases and histologic analysis evidenced involvement of the dura by tumors.
SF enhancement was evident in meningiomas and dura surrounding the lesions. Histologic analysis confirmed dural involvement. SF could represent an universally available fluorescent tool for meningioma surgery 2).
see Skin Preparation.
The incision and bone flap must be large enough to allow for excision of a good margin of dura around the tumor attachments.
The meningeal arteries are occluded as they are exposed.
These tumors can be removed intact by placing gentle traction on the dural attachment and working circumferentially around the tumor to divide the attachments to the cortex. However, if the surface of the tumor cannot be easily visualized without placing significant retraction on the cortex, internal decompression of the tumor is done and the capsule is reflected into the area of decompression.
In a situation where the tumor arises over the frontal temporal junction and grows into the sylvian fissure, the medial capsule and the dural attachment may extend down onto the lateral floor of the anterior fossa and anterior wall of the middle fossa, and the medial capsule of the tumor can be attached to branches of the middle cerebral artery.
A study showed that meningioma recurrence was unlikely when autologous cranioplasty was done with refashioned hyperostotic bone. This could be done in the same setting with meningioma excision. There was no recurrence at a mean of 5-year follow-up in convexity meningiomas 3).
An accurate and real-time model of soft tissue is critical for surgical simulation for which a user interacts haptically and visually with simulated patients. A paper focuses on the real-time deformation model of brain tissue for the interactive surgical simulation, such as neurosurgical simulation.
A new Finite Element Method (FEM) based model with constraints is proposed for the brain tissue in neurosurgical simulation. A new energy function of constraints characterizing the interaction between the virtual instrument and the soft tissue is incorporated into the optimization problem derived from the implicit integration scheme. Distance and permanent deformation constraints are introduced to describe the interaction in the convexity meningioma dissection and hemostasis. The proposed model is particularly suitable for GPU-based computing, making it possible to achieve real-time performance.
Simulation results show that the simulated soft tissue exhibits the behaviors of adhesion and permanent deformation under the constraints. Experiments show that the proposed model is able to converge to the exact solution of the implicit Euler method after 96 iterations. The proposed model was implemented in the development of a neurosurgical simulator, in which surgical procedures such as dissection of convexity meningioma and hemostasis were simulated 4).