The current worldwide, standards for diagnosis of cervical spinal myelopathy are the Nurick scale [
5] and the JOA score. Comparatively, the JOA score is the most useful, because the Nurick scale consists of only 6 simple grades. However, the JOA score is a physician-centered assessment tool created in 1975, which does not take into account patient satisfaction or quality of life. Both criteria are now considered important and are thus assessed by the JOACMEQ. Due to the emerging need to evaluate the impairments to patient activity in daily life, which is directly related to quality of life, various patient-oriented outcome measures, for example, the Short Form-36, have been developed and adopted by clinical practices in different medical fields. JOACMEQ was established to fulfill this need, as a self-rating questionnaire that could be filled out by patients themselves. Candidate questions included in the questionnaire were selected and modified from various preexisting outcome measures, including the Short Form-36, the Rolland and Morris Disability Questionnaire, and the Oswestry disability index. This questionnaire comprises 24 questions that were selected and validated through three large-scale studies. It designates the status of patients suffering cervical myelopathy from five different aspects, represented by five intuitive numerical scores. We found that the average JOA score was similar in both the CSM and OPLL groups. The transition of the average total JOA score before laminoplasty to that after laminoplasty have been documented elsewhere for patients with CSM and for those with OPLL:
The recovery rates in the studies for patients with CSM were as follows: Suda et al. [
7], 60.2%; Higashino et al. [
8], 43.4%; Yukawa et al. [
9], 60.6%. The recovery rates for patients with OPLL were as follows: Iwasaki et al. [
10], 63%; Ogawa et al. [
11], 63.1%. The recovery rates in our study corroborated those from previous studies, with rates for the OPLL groups slightly better than rates for the CSM groups. However, we found that scores on the JOACMEQ subscale for cervical spine function improved gradually after surgery in the CSM group, while those in the OPLL group did not improve at all. The CSM group showed more improvement than the OPLL group in function of the upper and lower extremities, as assessed by the JOACMEQ. Generally, these results were already known from clinical experiments but could not be evaluated in detail using only conventional assessment. There was no significant improvement in bladder function at any point, as assessed by the JOACMEQ. Median scores for quality of life on the JOACMEQ improved significantly after surgery, but the rate for effectiveness of assessment was lower in both the CSM and the OPLL groups. Thus, reaching a consensus on the JOACMEQ effectiveness rate was difficult. For example, when looking at the upper- and lower-extremity function in the CSM group, we could judge that surgery was effective because the effectiveness rate was about 50% and the postoperative median score improved significantly compared with the preoperative score. Yet when looking at the quality of life, we could not determine whether surgery was effective, since the effectiveness rate was below 30%, despite significant improvement of the postoperative median score as compared to the preoperative score. As shown in
Table 1, there was no consistent correlation between each JOACMEQ subscale and the JOA score. Therefore, we concluded that since both evaluation methods were quite different they are both needed until more widespread consensus on the interpretation of the JOACMEQ becomes available. There was a general correlation between JOA scores and scores on the JOACMEQ subscale for upper- and lower-extremity function, reflected by a lack of large distance between scores on the physician-centered tool (JOA) and those on the patient-centered tool (JOACMEQ). However, in the OPLL group, we found no obvious correlation between scores on the 2 assessment tools for either cervical spine function or quality of life; and in the CSM group, the correlation was low between scores on the 2 tools for cervical spine function. The new subscales of cervical spine function and quality of life were parameters that we could not assess with the JOA score. Most previous studies that assessed cervical spine function by evaluating the range of motion, degree of spinal curvature, or axial pain, did not provide adequate assessment with a patient-centered method. Agrawal et al. [
12] recently reported assessment of quality of life using Odom's criteria. Chagas et al. [
13] assessed quality of life with a 3-grade scale, Singh et al. [
14] did so by the Short Form-36, and Kotani et al. [
15] used the JOACMEQ subscale for quality of life. Despite all these prior assessments, no researcher had measured time-dependent postoperative changes affecting quality of life for patients with CSM or with OPLL. The salient feature of our study was the use of the JOACMEQ to assess cervical spine function and quality of life, parameters that cannot be assessed by the JOA scores. The JOACMEQ includes items assessed by the JOA score, but the JOACMEQ and the JOA score produce different findings because there is no consistent correlation between each JOACMEQ subscale and the JOA score. Hence both assessments should continue to be used until there is more consensual interpretation of the JOACMEQ. Our study had several limitations. Firstly, only 8 of the study subjects had OPLL. Secondly, the follow-up period was only 1 year. Thirdly, we could not easily implement our findings on the JOACMEQ because there was little consensus regarding the correspondence of its effectiveness rate to practical clinical relevance. The JOA score significantly corresponded to scores for the JOACMEQ subscales for upper- and lower-extremity function. However, for the OPLL group, the JOA score did not correlate with the JOACMEQ subscales for cervical spine function and quality of life. Moreover, in the CSM group, scores on the JOACMEQ cervical spine function subscale had little relation to JOA scores. These results indicated that the JOA score alone was not useful in assessing cervical spine function or quality of life.