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

Objective: 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.
Methods: 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.
Results: 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.
Conclusions: 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.
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