Comparison of Nurick grading system and modified Japanese Orthopaedic Association scoring system in evaluation of patients with cervical spondylotic myelopathy

Abstract

The purpose of this study was to determine the correlation between Nurick grade and modified Japanese Orthopaedic Association (mJOA) scores in the preoperative and postoperative follow-up evaluation of patients with cervical spondylotic myelopathy (CSM). This retrospective study included 93 patients with CSM who underwent central corpectomy (CC) between 1998 and 2008. Preoperative and postoperative Nurick grade and total mJOA (tmJOA) and lower limb mJOA (llmJOA) score of each patient was documented and the correlation between the Nurick grades and the mJOA scores was studied. At presentation and follow-up, correlation between Nurick grade and llmJOA (Spearman's ρ 0.901 and 0.886) was better than with tmJOA (0.846 and 0.862). The Nurick grade recovery rate (NGRR) correlated better with the llmJOARR than with tmJOARR (Spearman's ρ 0.840 and 0.793, respectively). Overall, the correlation of preoperative and follow-up scores and recovery rates was better in patients with moderate myelopathy than in those with mild or severe myelopathy. At follow-up, 78/93 (83.9%) patients had improved in their Nurick grades, whereas 88/93 (94.6%) had improved in their tmJOA scores and 73/93 (78.5%) in their llmJOA scores. Although Nurick grade and llmJOA had good correlation preoperatively, at follow-up evaluation after surgery, there was disagreement in 11.8% (11/93) patients. One of the major reasons for the discrepancy between the Nurick scale and the llmJOA at follow-up evaluation was the ability of patients to regain employment without an improvement in the llmJOA score. As disease-specific scales, both Nurick scale and mJOA score should be utilized in the evaluation of patients with CSM.