Brain tumor surgery affecting the left frontal aslant tract and clinical outcome: a study of 23 glioma patients

Abstract

Background The frontal aslant tract (FAT) is associated with speech initiation, though its surgical relevance remains debated. The arcuate fasciculus (AF) is linked to phonological and semantic processing, with a well-established role for lasting outcomes. Research question To investigate the impact of isolated and combined FAT and AF disruption on transient and lasting language deficits in glioma patients. Material and methods We retrospectively analyzed 23 patients with non-contrast-enhancing IDH-mutant gliomas affecting the left FAT. Language was assessed pre-, intra-, and postoperatively. Awake speech mapping using Penfield stimulation was performed in 15 (65.2%) and neurophysiological monitoring under general anaesthesia in 8 patients. The FAT and AF were reconstructed by diffusion tensor imaging tractography, and tract integrity was classified as intact, partially disrupted, or fully disrupted. Postoperative and follow-up language deficits were correlated with the degree of tract disruption. Results FAT disruption correlated with transient deficits (τ = 0.36, p = 0.059). AF involvement was associated with transient (τ= 0.30, p = 0.088) and persistent aphasia (τ = 0.53, p = 0.033). Combined FAT and AF damage was linked to an increased deficit of both immediate (τ = 0.44, p = 0.022) and lasting (τ = 0.49, p = 0.046) language outcomes. Discussion and conclusion FAT injury contributes to transient aphasic symptoms, whereas AF disruption reflects persistent impairment. Concurrent FAT and AF involvement amplifies both short-term and lasting deficits, supporting a network-based approach to tract preservation in glioma surgery.