Association between ligamentous stenosis at spondylolisthetic segments before fusion surgery and symptomatic adjacent canal stenosis at follow-up in patients with degenerative spondylolisthesis

Methods@#In total, 76 patients participated in this case-control study (neurologically symptomatic adjacent canal stenosis, n=33; neurologically asymptomatic cases at follow-up, n=43). Their risk factors during surgery and magnetic resonance (MR) images before the surgery and at follow-up were evaluated. Data from the two groups (n=25 each) were matched using propensity scores for age, sex, time to MR imaging at follow-up, surgical procedure, and LF hypertrophy in adjacent segments before the surgery and analyzed. @*Results@#Compared with the asymptomatic group, the symptomatic adjacent canal stenosis group had a significantly larger LF area/spinal canal area in the spondylolisthetic segments before the surgery. During the follow-up periods (in months), they had a larger LF area/ spinal canal area in the adjacent segments: the two values were significantly correlated. The sensitivity, specificity, and positive and negative predictive values for determining symptomatic adjacent canal stenosis were high compared with on the cutoff value for the LF area/spinal canal area at the spondylolisthetic segments before the surgery. These results were the same after matching. @*Conclusions@#Symptomatic adjacent canal stenosis is mainly caused by LF hypertrophy. Ligamentous stenosis at the spondylolisthetic segments before fusion surgery might be strongly associated with symptomatic adjacent canal stenosis at follow-up.

Prevalent morphometric vertebral fractures as a risk factor for subsequent clinical vertebral fractures after shortfusion surgery in older Japanese women with degenerative spondylolisthesis

Methods@#The study enrolled a total of 237 older female patients: 50 and 187 patients had prevalent morphometric VFs (VF [+] group) and nonprevalent morphometric VFs (VF [−] group), respectively. The time to subsequent clinical VFs after fusion surgery was compared between the two groups using the Kaplan-Meier method. Moreover, 40 and 80 patients in the VF (+) and VF (−) groups, respectively, were analyzed and matched by propensity scores for age, follow-up duration, surgical procedure, number of fused segments, body mass index, and number of patients treated for osteoporosis. @*Results@#Kaplan-Meier analysis indicated that the VF (+) group had a higher incidence of subsequent clinical VFs than the VF (−) group, and Cox regression analysis showed that the presence of prevalent morphometric VFs was an independent risk factor for subsequent clinical VFs before matching. Kaplan-Meier analysis demonstrated comparable results after matching. @*Conclusions@#The presence of prevalent morphometric VFs may be a risk factor for subsequent clinical VFs in older women with degenerative spondylolisthesis who underwent short-fusion surgery.

<b>1．The Achievements and Future Directions of MIHARI Project </b> / 薬剤疫学

PMDA, the Japanese regulatory agency, has worked for reinforcing and enhancing its post-marketing safety measures as stated in the second mid-term (FY 2009-2013) plan. MIHARI Project-Medical Information for Risk Assessment Initiative was started in FY 2009 to develop a new safety assessment system for post-marketing drugs using Japanese electronic healthcare data in PMDA. In the second mid-term, we examined characteristics of some electronic healthcare data available in Japan including, claims data, hospital information system data and Diagnosis Procedure Combination (DPC) data in order to make efficient use of those databases for the purpose of drug safety assessment. In addition, some pilot pharmacoepidemiological studies for risk assessment and drug utilization were conducted by use of these electronic healthcare data. Based on the accumulated findings, knowledge, and experiences from the pilot studies, we established the framework by FY 2013 to implement pharmacoepidemiology-based safety assessment in PMDA. In the third mid-term (FY 2014-2018), one of the important mission is to apply this framework into the current risk management process of drug safety. For that purpose, cooperation with other divisions of PMDA such as Office of Safety and Office of New Drug is a key. Simultaneously, we will work to establish an access to another database and novel pharmacoepidemiological methods using electronic healthcare data. A large-scale electronic health record database (MID-NET) as well as national claims database are expected to be an important database in the future activities of MIHARI Project. Furthermore, in April 2015, PMDA established new office focusing on Medical Informatics and Epidemiology for further promotion of electronic healthcare data utilization in Japan. In this article, we describe history and past activities of MIHARI Project followed by future challenges.