The Oswestry Risk Index

Abstract

The revised Tokuhashi, Tomita and modified Bauer scores are commonly used to make difficult decisions in the management of patients presenting with spinal metastases. A prospective cohort study of 199 consecutive patients presenting with spinal metastases, treated with either surgery and/or radiotherapy, was used to compare the three systems. Cox regression, Nagelkerke's R(2) and Harrell's concordance were used to compare the systems and find their best predictive items. The three systems were equally good in terms of overall prognostic performance. Their most predictive items were used to develop the Oswestry Spinal Risk Index (OSRI), which has a similar concordance, but a larger coefficient of determination than any of these three scores. A bootstrap procedure was used to internally validate this score and determine its prediction optimism. The OSRI is a simple summation of two elements: primary tumour pathology (PTP) and general condition (GC): OSRI = PTP + (2 - GC). This simple score can predict life expectancy accurately in patients presenting with spinal metastases. It will be helpful in making difficult clinical decisions without the delay of extensive investigations.

A validation of the Oswestry Spinal Risk Index

“…Consistently with the analyses of Balain et al [16], and because of low numbers of patients in certain classes in the current analysis, patients classified with OSRI scores of 2 and 3, and patients classified with OSRI scores of 4 and 5 were combined into single classes. For all patients, a Kaplan-Meier survival analysis was conducted to compare the survival experience of patients with varying OSRI scores.…”

“…The paper by Balain et al [16] proposing the OSRI found this score to have a Nagelkerke's pseudo R 2 statistic of 0.28. The hazard ratio of 1.75 obtained for the OSRI score in both models indicates that the hazard of death is raised by 75 % for each advance in the OSRI score.…”

“…A number of procedures were conducted to assess the validity of the OSRI score and its transferability across data sets; some of which are based on analyses presented by Balain et al [16]. Consistently with the analyses of Balain et al [16], and because of low numbers of patients in certain classes in the current analysis, patients classified with OSRI scores of 2 and 3, and patients classified with OSRI scores of 4 and 5 were combined into single classes.…”

“…The Oswestry Spinal Risk Index (OSRI) is a scoring system developed by Balain et al [16] that predicts survival in patients with MSCC. It is derived from the most predictive variables of the revised Tokuhashi [9], Tomita [8] and modified Bauer [10] scores.…”

“…It is derived from the most predictive variables of the revised Tokuhashi [9], Tomita [8] and modified Bauer [10] scores. In a cohort of 199 patients with metastases, Balain et al [16] found that the most important factors in predicting survival were the primary tumour pathology (PTP) and general condition (GC) of the patient based upon the Karnofsky score [17]. The PTP and GC are allocated scores and the formula: PTP ?…”