RESUMEN
STUDY DESIGN: Retrospective observational study. OBJECTIVE: To scrutinize screw motion used in semiconstrained rotational plate systems for anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: Semiconstrained rotational plate systems are supposed to control graft subsidence and facilitate lordosis acquisition and maintenance by toggling the instrumented vertebrae via variable-angle screws. However, their benefits may be unrealized if the screws move within the vertebrae. METHODS: We reviewed medical records of 119 patients who underwent 1-level, 2-level, 3-level, or 4-level ACDF, divided them into the short-segment (n=62, 1-level or 2-level ACDF) and long-segment (n=59, 3- level or 4-level ACDF) groups, and investigated their immediate and 1-year postoperative lateral radiographs. We measured the fused segmental angle, screw angles at the upper-instrumented vertebra (UIV) and lower-instrumented vertebra (LIV), distance from the screw base to the endplate of UIV/LIV (SBE), and distance from the screw tip to the endplate of UIV/LIV (STE) to analyze the screw motion used in these plate systems. The differences between the immediate and 1-year postoperative values were statistically analyzed. The nonunion level was also investigated. RESULTS: Screw angle and SBE at the LIV significantly decreased in the long-segment group (-14.5±9.8 degrees and -2.8±1.8 mm, respectively) compared with those in the short-segment group (-4.6±6.0 degrees and -1.0±1.5 mm, respectively). Thus, the long-segment group could not maintain the immediate-postoperative segmental angle. Overall, 27 patients developed nonunion, with 19 (70.4%) in the long-segment group and 21 (77.8%) at the lowest fused level. CONCLUSIONS: Semiconstrained rotational plate systems provide only vertical forces to the fused segment rather than toggling the instrumented vertebrae. Postoperatively in multilevel ACDF, LIV screws migrate caudally, suggesting that these plate systems are not always effective in maintaining lordosis. Moreover, LIV screws and the anterior wall of the LIV are subject to overloading, resulting in a high rate of nonunion at the lowest fused level. LEVEL OF EVIDENCE: Level III.
RESUMEN
A 15-year-old girl had experienced hip pain at 11 years of age. At 15 years of age, the patient complained of persistent generalised pain. Her rheumatoid factor and serum matrix metalloproteinase-3 levels were below standard values; there were no inflammatory responses, and the human leukocyte antigen test was negative for B27 and positive for B52 and B62. The bath ankylosing spondylitis disease activity index (BASDAI) value was 8.0 at the time of induction and 3.1 at 6 months after the introduction of adalimumab (at a dose of 40 mg). The BASDAI value improved with an increase in the dose of adalimumab to 80 mg at 8 months after the initial introduction of adalimumab (at 40 mg), although it remained at 4.8 at 16 months after the dose increase. The BASDAI value was 2.6 at 6 months, 2.7 at 1 year, and 1.8 at 1.5 years after the introduction of infliximab, indicating that the patient had progressed well without any adverse events. Based on this case, juvenile ankylosing spondylitis is a differential diagnosis for low back pain and generalised pain since childhood. Tumour necrosis factor (TNF) inhibitors were promptly introduced in this case, although it took 4 years from the initial presentation. TNF inhibitors were effective in treating juvenile ankylosing spondylitis in the present case without any adverse events. This case is notable because juvenile onset ankylosing spondylitis is one of the reasons for severe lumbago since childhood and because TNF inhibitors were administered promptly after diagnosis.
Asunto(s)
Adalimumab , Antirreumáticos , Espondilitis Anquilosante , Factor de Necrosis Tumoral alfa , Humanos , Espondilitis Anquilosante/tratamiento farmacológico , Espondilitis Anquilosante/diagnóstico , Femenino , Adolescente , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Adalimumab/uso terapéutico , Adalimumab/administración & dosificación , Resultado del Tratamiento , Antirreumáticos/uso terapéutico , Antirreumáticos/administración & dosificación , Infliximab/uso terapéutico , Infliximab/administración & dosificación , Índice de Severidad de la EnfermedadRESUMEN
BACKGROUND: Castellvi type III and IV lumbosacral transitional vertebrae (LSTVs) are fused to the sacrum. In these cases, the pelvic incidence (PI) and pelvic tilt (PT) may vary according to the selected "S1." This study aimed to determine the optimum vertebral level of these LSTVs when measuring PI and PT. METHODS: PI and PT were measured twice in 56 patients with type III and IV LSTVs with a balanced spine, with LSTV considered as the lowest lumbar vertebra (LLV) or S1. PI and PT measured with LSTV as LLV were denoted as LLV_PI and LLV_PT, and those measured as S1 were denoted as S_PI and S_PT. Reference ranges (mean -2 SD to +2 SD) of PI and PT were derived from 183 non-LSTV patients with a balanced spine as 35.5° to 68.8° (PI) and 2.5° to 29.6° (PT). If S_PI, S_PT, or both were below the reference range, the LSTV was interpreted as LLV. If LLV_PI, LLV_PT, or both were above the reference range, it was interpreted as S1. If all parameters were within the respective reference range, it was interpreted as an intermediate type. RESULTS: The optimum vertebral level of LSTV was S1 (n = 29, 51.8%), most frequently due to high LLV_PT (35.4°±4.7), followed by LLV (n = 14, 25%) due to low S_PI (31.5°±5.2) and intermediate type (n = 13, 23.2%). CONCLUSIONS: If PI is too small or PT is too large to represent the actual sagittal alignment in patients with Castellvi type III and IV LSTVs, the selected S1 should be reconsidered. CLINICAL RELEVANCE: PI and PT measurements can be used to determine whether the optimum vertebral level of Castellvi type III and IV LSTV should be considered LLV or S1.
RESUMEN
Supramolecular nanofibers composed of the closed-ring isomer of a diarylethene formed bundles in a methylcellulose aqueous solution by depletion force while the spheres composed of the open-ring isomer were not coagulated. Upon irradiation with UV light to the suspension of the open-ring isomer, fibers were found to be generated and the formed submillimeter-sized bundles showed a photoinduced shrinking of more than 100 µm under visible light irradiation.
RESUMEN
Photoinduced clustering of polystyrene microbeads and photocontrol of their diffusion was achieved in water with the assistance of photoinduced transformation of supramolecular architecture of amphiphilic diarylethene between sphere and fiber states. When a suspension of polystyrene beads containing the sphere state of diarylethene was UV-irradiated from beneath, clustering of the polystyrene beads by thermal convection was observed. The velocity of clustering was dependent on the amount of photogenerated nanofibers that determines the viscosity of the water. Diffusion of the clustered polymer beads was suppressed by the surrounding fibers, but was restored to regular Brownian motion upon irradiation with visible light. It was suggested that the diffusion of the microbeads was controlled by the transformation of aggregates between the more viscous fiber state and the less viscous sphere state. These results provide new insight into the photocontrol of particle motion in fluidic media.
RESUMEN
We performed maximal exercise tests on 6 men using a bicycle ergometer and then measured the ferric-reducing ability in plasma to clarify the relationship between antioxidant status and exercise intensity. The ferric-reducing ability showed a rectilinear increase with the increase in exercise intensity, whereas the generation of hydroxyl radicals showed a decrease with the increase in exercise intensity. Also, the generation of hydroxyl radicals showed a symmetrical correlation to lactate level in plasma. These results suggest that antioxidant ability is enhanced with an increase in exercise intensity, and that the lactate level, which increases with physical exercise, may act as a scavenger of free radicals.