Purpose A retro-odontoid pseudotumor is usually a reactive fibrocartilaginous mass associated with atlantoaxial subluxation (AAS). However, a retro-odontoid pseudotumor not associated with AAS, which undergoes spontaneous regression following C1 laminoplasty, has been reported. The purpose of this study was to report surgical outcomes of C1 laminectomy for retro-odontoid pseudotumor without AAS. Materials and methods The cases of seven patients (mean age 75.6 ± 7.6 years-old) with retro-odontoid pseudotumor without AAS were reviewed. The mean follow up time was 52.3 ± 25.5 months. Each patient underwent a C1 laminectomy with an additional C3-6 expansion laminoplasty in three patients. The Japanese Orthopaedic Association score (JOA score) was used for neurological assessment. Pseudotumor size and additional AAS were analyzed using MRI and radiography. Results All patients exhibited neurological improvement following surgery, the JOA score improved from 7.2 ± 3.2 to 14.1 ± 2.6. The mean O-C2 and C2-7 angle decreased from -3.2 ± 2.1°to -3.9 ± 1.7°, showing a slight kyphotic change. Postoperative AAS was not observed. All pseudotumors spontaneously resolved, and recurrence and regrowth were not observed. Five patients had MRIs after gadolinium administration; four patients who showed enhancement of the pseudotumor had almost complete reduction within 1 year following surgery.Discussion Our study, assessing the outcome of C1 laminectomy for retro-odontoid pseudotumor, found neurological improvement in all cases. Since all pseudotumors were reduced and additional AAS was not observed, C1 laminectomy for retro-odontoid pseudotumor, in the absence of AAS, is recommended as a therapeutic strategy.

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The aims of the present study were to investigate the efficacy of measuring bovine urinary zearalenone (ZEN) concentrations by using a commercially available ELISA method in cattle kept under different feeding conditions to monitor the natural contamination of feeds at the farm level, and to investigate the effects of supplementation of a mycotoxin adsorbent (MA) product in the feed based on urinary ZEN concentration. First, Japanese Black cattle herds kept for breeding (4 herds) and fattening (4 herds) purposes were provided with similar feeding conditions. Then, urinary samples from 5 cows in each herd were collected and analyzed. Second, dairy cows from 1 herd fed with total mixed rations (TMR) were selected. After thorough mixing of the MA (40 g/d) with TMR, the supplemented TMR was fed according to the following schedule: with MA for 2 wk, without MA for 3 wk; then with MA for 2 wk and without MA for 6 wk. Urine samples were collected from cows (n = 6 to 7) and examined before and after each interval. Zearalenone concentrations were measured by the ELISA and liquid chromatography-tandem mass spectrometry methods. The concentration of ZEN and its metabolites was expressed after creatinine (Crea) correction [ZEN or metabolites (pg/mL)/Crea (mg/dL); pg/mg of Crea]. In the first experiment, the urinary concentrations of ZEN and its metabolites were variable in all herds, and significant differences were observed between herds. In 1 fattening herd, in particular, urinary ZEN concentrations were greater (P < 0.001) than in the other 3 herds. This might reflect significant natural ZEN contamination of the feed at the farm level. In Exp. 2, urinary ZEN concentrations displayed peculiar trends after supplementation with MA. After 2 wk of supplementation, a significant decrease of ZEN (P < 0.05) was observed. Zearalenone concentrations remained at a reduced amount during 3 wk without MA supplementation and 2 wk with MA supplementation. When MA was not added to the feed for the next 6 wk, the concentrations increased to the original quantity. These findings indicate the usefulness of measuring concentrations of urinary ZEN and its metabolites not only for monitoring the natural ZEN contamination of cattle feed at the farm level but also for in vivo evaluation of MA function after supplementing feeds with MA.

The results of the present study demonstrate impairment of postural stability in patients with cervical myelopathy. The stabilometer can objectively evaluate the postural stability, which may reflect the function of the dorsal columns and the corticospinal tracts. Thus, stabilometry is a useful method for measuring a part of proprioceptive function and for objective assessment of the lower limb function of cervical myelopathy.

In this paper, we report on a terahertz (THz) sensing system. Compared to previously reported systems, it has increased system sensitivity and reduced size. Both are achieved by using a photonic crystal (PC) cavity as a resonator and compact resonant tunneling diodes (RTDs) as signal source and as detector. The measured quality factor of the PC cavity is higher than 10,000, and its resonant frequency is 318 GHz. To demonstrate the operation of the refractive index sensing system, dielectric tapes of various thicknesses are attached to the PC cavity and the change in the resonator's refractive index is measured. The figure of merit of refractive index sensing using the developed system is one order higher than that of previous studies, which used metallic metamaterial resonators. The frequency of the RTD-based source can be swept from 316 to 321 GHz by varying the RTD direct current voltage. This effect is used to realize a compact frequency tunable signal source. Measurements using a commercial signal source and detector are carried out to verify the accuracy of the data obtained using RTDs as a signal source and as a detector.

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Unicompartmental knee arthroplasty (UKA) is a less invasive method for treating monocondylar arthritis of the knee than total knee arthroplasty (TKA). The use of UKA is gaining popularity and has shown excellent long-term results. 1,2) The survivorship of medial mobile bearing Oxford UKA (OUKA; Zimmer Biomet, Warsaw, IN, USA) is as high as 98% at 10 years 3) and 91% through the second decade. 4) One of the most serious complications of UKA is tibial fracture. It has been described as a result of technical errors, such as the creation of an improper pin site for the fixation of the tibial cutting block, 5) vertical overcutting of the medial plateau, 6) use of an excessive force with a heavy hammer, 7) and breach of the posterior tibial cortex during preparation of the tibial plateau for the implant. 8) Although rarely reported as a complication in Europe (less than 1%), 7,9,10) tibial fracture is reported more frequently in Asian countries. 11) Yoshida et al. 12) described that the 10-year survival rate of >1,000 cases of OUKA in a Japanese population was 95.4%, with good clinical results. However, fractures after UKA were reported to occur in 7.2% of cases in spite of good technical skill. 13) It may indi-