gms | German Medical Science

Objective: The resection of language eloquent brain tumors is a challenge, whereby the surgical planning still depends strongly on anatomical models and individual experiences. Since morbidity is typically caused by an impairment of white matter connectivity, we aim to establish language tractography as a valid tool for preoperative risk assessment and surgical planning in a routine neurosurgical work flow.

Methods: This prospective study includes a series of 50 surgical cases of patients with left perisylvian gliomas. Every patient received a preoperative DTI tractography of the 5 main language tracts (AF, ILF, IFOF, UF, FAT) and a detailed analysis of the spatial relations of the tumor and the respective tracts. The language status was assessed preoperatively, postoperatively and after 3 months by using the Aachener Aphasia Test (AAT). The postoperative MRI scan was fused with the preoperative MRI applying careful distortion correction to detect potential impairment of tracts and correlated with the functional outcome 3 months after surgery.

Results: In 27 % of patients a new permanent language deficit was detected. The minimal distance between AF and tumor (p = 0,034) and especially an overlap between the temporo-parietal part of the AF and tumor (p = 0,007) correlated with new permanent aphasia. In respect to the postoperative resection map analysis, injury of the temporo-parietal as well as the temporal part of the AF (p = 0,009; p = 0,004) and injury to the anterior ILF (p = 0,01) and the middle part of the IFOF (p = 0,001) significantly correlated with new language deficits. The important role of the temporo-parietal AF (OR: 6,429; CI: 1,421 – 29), anterior ILF (OR: 4,971; CI: 1,171 – 21,101) and middle IFOF (OR: 8,679; CI: 2,053 - 36) for preservation of language function was confirmed by univariate binary logistic regression (p < 0,05).

Conclusion: The spatio-functional correlation between tumor and the subcortical language network as revealed by DTI tractography correlates with the individual postoperative functional outcome. In line with earlier studies applying intraoperative mapping during awake surgery, the temporo-parietal AF, the anterior ILF and the middle IFOF were identified as especially vulnerable parts within the network. Based on these findings, standardized presurgical tractography of language tracts can be regarded as a promising technique for preoperative risk stratification in patients with language eloquent gliomas.