High-grade glioma surgery
The postoperative seizure freedom represents an important secondary outcome measure in glioblastoma surgery. Supra-total glioblastoma resection in terms of anterior temporal lobectomy (ATL) has gained growing attention with regard to superior long-term disease control for temporal-located glioblastoma compared to conventional gross total resections (GTR). However, the impact of ATL on seizure outcome in these patients is unknown.
ATL in terms of a supratotal resection strategy was associated with superior favorable seizure outcome following temporal glioblastoma resection compared to GTR. Regarding the above-mentioned survival benefit following ATL compared to GTR, ATL as an aggressive supra-total resection regime might constitute the surgical modality of choice for temporal-located glioblastoma 1).
Indications
see Glioblastoma surgery indications.
Complications
see high-grade glioma surgery complications.
Technique
Surgical treatment
Current methods of clinical imaging do not elucidate the full extent of brain invasion, making it difficult to predict which, if any, patients are likely to benefit from gross total resection.
Quantification of relative invasiveness assessed from routinely obtained pre-operative imaging provides a practical predictor of the benefit of gross total resection 2).
The primary obstacle in surgical treatment lies in differentiation between healthy and pathological tissue at the tumor margins, where current visualization methods reach their limits.
see 5 aminolevulinic acid fluorescence guided resection of high-grade glioma.
Since 2005, state-of-the-art therapy in glioblastoma multiforme consists of maximal safe resection followed by combined radiotherapy and chemotherapy with temozolomide, according to Stupp regimen 3). 4) , particularly in patients that demonstrate MGMT promoter methylation. At recurrence there is no consensus as to the standard of care as no therapeutic options have produced substantial survival benefit 5).
A growing body of evidence indicates that surgery prolongs survival in glioblastoma multiforme patients if an extensive part of the contrast-enhancing tumor is resected, although all therapies for glioblastoma are essentially palliative for most patients.
Standard surgical resection is guided by enhancement on postcontrast T1 weighted image, which is insufficient for delineating surrounding infiltrating tumor.
Surgery is still essential to obtain brain tissue for pathological analysis, and reduce mass effect. Intraoperative magnetic resonance imaging, neuronavigation, ultrasonography, and fluorescence-guided surgery are the most used tools worldwide. 5-Aminolevulinic acid surgery, combined with Stupp protocol, produces a median survival of 15 months. The objectives of perioperative positioning are to enhance optimal exposure, prevent injury related to position, and maintain normal body alignment without excess flexion, extension, or rotation. Advances in surgical techniques have contributed to enhanced recovery after tumor resection, improved postoperative functional status, and decreased length of stay in the hospital 6).
An ongoing challenge in surgical resection of brain lesions is balancing the goal of maximizing resection with the need to preserve function. This is especially salient in the setting of epilepsy and glioma surgery where the lesions can be cortically based and intimately involved with eloquent regions. In both situations, resection around a seizure focus or maximizing tumor removal enhances clinical outcomes with regard to seizure freedom or survival, respectively 7) 8) 9) 10) 11) 12).
A Cochrane study found low to very low quality evidence that image-guided surgery using iMRI, 5-ALA or DTI-neuronavigation increases the proportion of patient with complete tumor resection on post-operative MRI. Moreover, theoretical concerns that maximizing the EOR would lead to more frequent adverse side effects was poorly reported in the included studies, as were the effects of image guidance on survival and quality of life 13).
Despite these findings, these modalities are thus far the most efficacious methods available for accurate and precise tumor resection.
Extent of resection
see Glioblastoma extent of resection.
The current neurosurgical goal for patients with high-grade glioma is maximal safe resection of the contrast-enhancing tumor. However, a complete resection of the contrast-enhancing tumor is achieved only in a minority of patients. One reason for this limitation is the difficulty in distinguishing viable tumor from normal adjacent brain during surgery at the tumor margin using conventional white-light microscopy. To overcome this limitation, 5 aminolevulinic acid fluorescence guided resection of high-grade glioma has been introduced.
high-grade glioma is incurable in spite of modern neurosurgery, radiotherapy, and chemotherapy. Novel approaches are in research, and immunotherapy emerges as a promising strategy