A comparative analysis of the modified Rankin Scale, Karnofsky Performance Status and Kurtzke expanded disability status scale in the perioperative management of patients with brainstem cavernous malformations

Abstract

BackgroundThe neurological conditions of brainstem cerebral cavernous malformation (BCM) patients are usually ascertained using Karnofsky Performance Status (KPS) or the modified Rankin scale (mRS). However, these scales do not reflect slight changes in brainstem function, because neither KPS nor mRS includes brainstem symptoms such as worsening of swallowing or diplopia. The main problem when managing the BCM patients is that we can neither systematically record neurological changes nor conduct clinical outcome investigations of BCM due to the lack of an adequately detailed assessment system. PurposeWe investigated the usefulness of the Kurtzke expanded disability status scale (EDSS), which is already in widespread clinical use for multiple sclerosis because it provides certainty in evaluating brainstem symptoms. MethodsWe retrospectively analyzed neurological transitions in surgical BCM cases using the modified Rankin scale (mRS), Karnofsky performance status (KPS), and EDSS. We compared each neurological score transition, and determined which scale allows the most accurate recording of neurological changes in patients. ResultsWe proposed lesion removal for patients who showed both neurological deterioration and lesion enlargement caused by re-bleeding, and the surgery was accepted by 10 patients. EDSS allowed us to assess patient status more accurately than KPS or mRS particularly during the perioperative period. In the statistical analysis, only EDSS differed significantly during the period between the initial proposal of surgery and the immediate preoperative period. ConclusionOur results suggest EDSS to be superior for managing BCM patients, as compared to KPS and mRS. Thus, EDSS may serve as an alternative scale for assessing BCM patients.