Clinical and prognostic implications of rim restriction following glioma surgery

Abstract

Rim restriction surrounding the resection cavity of glioma is often seen on immediate post-op diffusion-weighted imaging (DWI). The etiology and clinical impact of rim restriction are unknown. We evaluated the incidence, risk factors and clinical consequences of this finding. We evaluated patients that underwent surgery for low-grade glioma (LGG) and glioblastoma (GBM) without stroke on post-operative imaging. Analyses encompassed pre- and postoperative clinical, radiological, intraoperative monitoring, survival, functional and neurocognitive outcomes. Between 2013 and 2017, 63 LGG and 209 GBM patients (272 in total) underwent surgical resection and were included in our cohort. Post-op rim restriction was demonstrated in 68 patients, 32% (n = 20) of LGG and 23% (n = 48) of GBM patients. Risk factors for restriction included temporal tumors in GBM (p = 0.025) and insular tumors in LGG (p = 0.09), including longer surgery duration in LGG (p = 0.008). After a 1-year follow-up, LGG patients operated on their dominant with post-op restriction had a higher rate of speech deficits (46 vs 9%, p = 0.004). Rim restriction on postoperative imaging is associated with longer duration of glioma surgery and potentially linked to brain retraction. It apparently has no direct clinical consequences, but is linked to higher rates of speech deficits in LGG dominant-side surgeries.

Risk factors and prognostic implications of surgery-related strokes following resection of high-grade glioma

“…A recent study by Strand et al also found a higher risk for peri-tumoral strokes in the temporal lobes, yet they included both rim-pattern and sector shaped DWI restrictions in their definition of strokes 8 . Our study focused only on wedge-shaped ischemic lesions, while minimal or rim-pattern DWI changes in the periphery of the resection cavity, often defined as post-operative restrictive changes, were not considered as ischemic strokes 18 . We perform most of our surgical resections trans-cortically, yet our assumption is that even mild retraction, often required in temporal and insular tumors, might be enough to induce ischemia in diseased brain parenchyma, especially in recurrent or previously irradiated cases.…”