The kaon photoproduction is investigated at the threshold energy. We discuss ͑i͒ the difference between the pseudoscalar ͑PS͒ and the pseudovector ͑PV͒ coupling descriptions on the KNY interaction, ͑ii͒ the contributions of t-channel poles of vector and axial vector mesons, and ͑iii͒ the contributions of nucleon and hyperon resonances to the E 0 ϩ amplitude. We suggest that total cross sections near threshold can be used to estimate the leading coupling constant, g KN⌳ and to make clear which description is the better of PS and PV coupling schemes for this reaction from future experiments. ͓S0556-2813͑96͒01010-2͔PACS number͑s͒: 25.20. Lj, 25.80.Nv, 13.75.Jz

To analyze the surgical outcomes of patients who underwent 1-level, 2-level, and 3-level anterior cervical discectomy and fusion (ACDF). Methods: We retrospectively assessed 182 patients with symptomatic cervical degenerative disease who underwent ACDF with allograft and a plate at our institution between January 2012 and March 2014. After only including patients with a >24 month follow-up, 142 fulfilled our inclusion criteria (71 underwent 1-level, 46 underwent 2-level, and 25 underwent 3-level ACDF). The assessment tools included the Short Form-36 (SF-36), Neck Disability Index (NDI), and visual analog scale (VAS). The fusion status was measured by radiography at 24 months postoperatively. Statistical analyses were performed with SPSS version 20.0. Results: The fusion rate was 84% in the 3-level group, 98.6% in the 1-level group, and 97.8% in the 2-level (p=0.017). There was a significant difference between 2-level vs. 3-level ACDF (p=0.049). Complications occurred in 4 (16%) patients of the 3-level group, 2 (2.8%) patients of the 1-level group, and 1 (2.2%) patient of the 2-level group (p=0.030). The subsidence rate was significantly higher in the 3-level group than in the other 2 groups (52%, p=0.047). Significant differences were observed between groups in terms of the NDI and SF-36 at the last follow-up (p=0.040 and p=0.046, respectively). Conclusion: The surgical outcome of the 3-level ACDF group was worse than that of the 1level or 2-level ACDF groups, which was indicated by the lower fusion rate, higher complication rate, and higher subsidence rate.

Objective: X-ray has been used for visualizing internal lesions despite of its biological hazard. Fluoroscopic technique is essential in the modern spinal interventions due to its simplicity and sharpness. Radiation hazard is often under estimated due to Intangible property and late effect. The purpose of this study was to assess radiation exposure during percutaneous vertebroplasty (PVP) which is one of the most frequently performed spinal interventions. Methods: We performed a prospective analysis of a total of 17 consecutive cases of PVP between January 2012 to august 2012. Sixteen patients were osteoporotic compression fractures. One case underwent PVP for pathological compression fracture. Exposure time was calculated automatically by a fluoroscope. For medical personnel, we put a thermoluminescent dosimeters (TLD) on the midpoint of the sternum inside a body apron and another one on the midpoint of a thyroid protector. For patients, one TLD was placed on the table anterior to patient's neck and another one on the table anterior to the treatment level. All TLDs were sent to the lab immediately after PVP. The cumulative dose recorded for each TLD badge was analyzed. Results: The exposure time per one vertebra was 323.77±23.96 seconds, ranging 207.00 to 547.00 seconds. The exposure dose measured on a thyroid protector was 2.97±0.54 mSv, ranging 2.11 to 3.21 mSv in the surgeon, 0.04±0.11 mSv, ranging 0.02 to 0.14 mSv in the assistant surgeon, and 0.11±0.02 mSv, ranging 0.08 to 0.15 mSv in the nurse. The exposure dose measured in the radio-protective apron was 0.20±0.04 mSv, ranging 0.15 to 0.30 mSv in the surgeon, 0.01±0.005, ranging 0.005 to 0.03 mSv in the assistant surgeon, and 0.04±0.01 mSv, ranging 0.02 to 0.10 mSv in the nurse. The patient showed 0.44±0.14 mSv, ranging 0.33 to 0.54 mSv in the neck area and 3.97. 0.52 mSv, ranging 3.44 to 4.12 mSv in the treated area. Conclusion: The amount of radiation exposure was different among medical personnel in performing PVP. The major contributing factor of this difference is supposed to be the distance from a fluoroscope. In addition to wear proper X-ray protective gears and reduce X-ray shooting time, we can further minimize radiation exposure by standing aside from the fluoroscope.