Quantitative MRI Tractography of White Matter Tracts After Tumor Craniotomy Surgery: Comparative Analysis Between Tubular Retractor and Open Craniotomy Surgery.

Background and objectives: Tubular retraction has been a technique used to minimize the extent of cerebral retraction injury; however, only qualitative imaging assessments exist in the literature comparing this technique with open craniotomies using spatula retraction. This study uses quantitative MRI tractography to analyze the extent of cerebral retraction injury using tubular retraction (TR) compared with open craniotomies (OC).

Methods: This study performed a retrospective analysis of a cohort of 20 patients who underwent cranial tumor surgery for deep-seated brain tumors. Ten patients who underwent surgery with TR were case-control matched with 10 patients who underwent an OC with spatula retraction. Quantitative metrics evaluating white matter tract integrity (fractional anisotropy (FA), geodesic anisotropy (GA), mean diffusivity, radial diffusivity, axial diffusivity, and tract volume), extent of resection, and neurological outcome were compared between the groups.

Results: Twenty patients underwent cranial surgery for deep-seated brain lesions. Preoperative neurological and tumor characteristics were comparable between the 2 cohorts. Postoperative extent of resection was found to be 90.4% in the TR group and 94.8% in the OC group (P = .395). Significant improvement was seen in the change in Karnofsky Performance Score from preoperative to postoperative status in the TR group, an 11-point increase, compared with the OC group, no change in score (P = .035). Quantitative metrics evaluating overall axonal status (FA) and compression (GA) showed significant signs of improvement in the TR group, with an FA of 0.322 vs 0.029 in the OC group (P = .011). GA was found to increase in the TR group (0.441) and decrease in the OC group (0.411, P = .0.012). Diffusivity metrics, evaluating axonal integrity were comparable between the 2 groups.

Conclusion: Tubular retraction surgery provides a viable surgical option for deep-seated tumors that provides comparable extent of resection outcomes while mitigating the effects of some components of retraction injury.