Responsiveness of the Zurich Claudication Questionnaire, the Oswestry Disability Index, the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, the 8-Item Short Form Health Survey, and the Euroqol 5 dimensions 5 level in the assessment of patients with lumbar spinal stenosis.

PURPOSE: To assess the responsiveness of the Zurich Claudication Questionnaire (ZCQ), the Oswestry Disability Index, the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, the visual analog scale (VAS), the 8-Item Short Form Health Survey (SF-8), and the EuroQol 5 dimensions 5 level as methods of assessing outcomes of surgery for lumbar spinal stenosis. METHODS: We analyzed 218 patients who had undergone lumbar surgery for spinal stenosis and completed one year of follow-up. The internal responsiveness of each questionnaire and any domains was assessed by the effect size and standardized response mean. External responsiveness was assessed by the Spearman rank correlation coefficient and the receiver operating characteristics (ROC) curve. RESULTS: The most responsive assessments were "symptom severity" and "physical function" on the ZCQ, "walking ability" on the JOABPEQ, "leg pain" on the VAS, and "social function" on the JOABPEQ. The moderately responsive assessments were the physical component summary on the SF-8, the ODI, the EQ5D-5L, "low back pain" on the JOABPEQ, and "leg numbness" on the VAS. The least responsive assessments were "low back pain" on the VAS, "mental health" and "lumbar function" on the JOABPEQ, and the mental component summary on the SF-8. CONCLUSIONS: Because of its high responsiveness, "symptom severity" on the ZCQ is recommended as a primary tool for assessing outcome when designing prospective studies for lumbar spinal stenosis.

Digital zoom is a useful, simple, and cost-effective method of reducing radiation exposure in percutaneous coronary intervention.

Reducing radiation exposure is a very important issue in interventional cardiology techniques such as percutaneous coronary intervention. Although novel techniques to reduce radiation exposure are valuable, we should also reconsider older techniques. Digital zoom has been available in Japan from 2005. Digital zoom enlarges an 8-inch field of view (FOV) by 1.2 times, allowing visualization of a 6.7-inch FOV without FOV switching. We identified 2101 suitable cases of percutaneous intervention (PCI) and divided them into two groups according to the use of digital zoom; 1195 patients were included in the digital zoom group and 906 patients in the conventional group. We collected data regarding the reference air kerma (RAK) and dose-area product (DAP). We calculated RAK and DAP per minute fluoroscope time (RAK/min, DAP/min, respectively). There were intergroup differences in RAK, DAP, RAK/min, and DAP/min (digital zoom group vs conventional group; RAK, 1590 mGy [990-2410] vs 1850 [1220-2720], p < 0.01, RAK/min; 54.7 mGy/min [38.5-73.2] vs 71.2 [51.5-93.0], p < 0.01; DAP, 16,000 cGy × cm2 [10,300-24,400] vs 20,700 [13,400-29,500], p < 0.001; DAP/min, 557 cGy × cm2/min [392-737] vs 782 [571-1010], p < 0.01, respectively). Because of baseline differences between the two groups, we performed propensity score matching. Even after score matching, there were intergroup differences in DAP, DAP/min, RAK, and RAK/min. Furthermore, the least squares method showed that digital zoom is a significant predictor of RAK (ß = 0.14, p < 0.01) and DAP (ß = 0.20, p < 0.01). Digital zoom is an older cost-effective technique that can significantly reduce radiation exposure in PCI.