Lesion-to-Eloquent Fiber Distance Is a Crucial Risk Factor in Presurgical Evaluation of Arteriovenous Malformations in the Temporo-occipital Junction

Abstract

Temporo-occipital junction arteriovenous malformations (TOJ-AVMs) do not often involve eloquent brain cortex, but rather exist beside functional fiber tracts. The objective of this study was to determine the outcomes after surgical treatment in patients with TOJ-AVMs and to identify risk factors associated with postoperative neurologic deficits. We retrospectively studied 41 patients with TOJ-AVMs. All patients underwent preoperative diffusion tensor imaging. Every potentially involved function (visual field and language) was studied as an independent function object (FO). The function-related optic radiation or arcuate fasciculus was tracked. Lesion-to-eloquent fiber distances (LFDs) were analyzed in regard to postoperative neurologic deficits. The areas under the receiver operating characteristic curves were compared. There were 58 FOs analyzed. Of these, 26 (44.8%) FOs led to short-term neurologic deficits, and 21 (36.2%) FOs resulted in long-term neurologic deficits. LFD was a significant predictor of short-term (P= 0.002) and long-term (P= 0.007) neurologic deficits. The Spetzler-Martin (S-M) score was associated with short-term neurologic deficits (P= 0.045), but it was not associated with long-term neurologic deficits. The area under the receiver operating characteristic curve of LFD was higher than that of the S-M score in predicting short-term neurologic deficits (0.89 vs. 0.72, P= 0.04) and long-term neurologic deficits (0.90 vs. 0.62, P= 0.002). The cutoff point for LFD in predicting long-term neurologic deficits was 3.10 mm. Patients with TOJ-AVMs have a high risk of surgical morbidity, although they often have relatively low S-M scores; LFD is a crucial risk factor associated with postoperative neurologic deficits in patients with TOJ-AVMs.