Surgical Approaches to Thalamic Gliomas: A Systematic Review.

BACKGROUND: Adult thalamic gliomas (ATGs) present a surgical challenge given their depth and proximity to eloquent brain regions. Choosing a surgical approach relies on different clinical variables such as anatomical location and size of the tumor. However, conclusive data regarding how these variables influence the balance between extent of resection and complications are lacking. We aim to systematically review the literature to describe the current surgical outcomes of ATG and to provide tools that may improve the decision-making process. METHODS: Literature regarding the surgical management of ATG patients was reviewed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Four databases were queried and a description of clinical characteristics and survival analysis were performed. An individual patient data analysis was conducted when feasible. RESULTS: A total of 462 patients were included from 13 studies. The mean age was 39.8 years with a median preoperative Karnofsky performance scale of 70. The lateral approaches were most frequently used (74.9%), followed by the interhemispheric (24.2%). Gross total and subtotal/partial resections were achieved in 81%, and 19% of all cases, respectively. New permanent neurological deficits were observed in 51/433 patients (11.8%). individual patient data was pooled from 5 studies (n = 71). In the multivariate analysis, tumors located within the posterior thalamus had worse median overall survival compared to anterior gliomas (14.5 vs. 27 months, P = 0.003). CONCLUSIONS: Surgical resection of ATGs can increase survival but at the risk of operative morbidity. Knowing which factors impact survival may allow neurosurgeons to propose a more evidence-based treatment to their patients.