BACKGROUND: This study attempts to prove a cause and effect relationship between spine immobilization following posterior fixation for unstable burst fractures and degeneration observed following hardware removal. METHODS: We enrolled 57 patients (259 intervertebral discs [IVDs]) who underwent only posterior instrumentation without fusion for thoracolumbar and lumbar unstable burst fractures. We arbitrarily named the IVD that has an endplate fracture after immobilization using pedicle screws as the fractured endplate and immobilized disc (FEID), the IVD that has no endplate fracture after immobilization using pedicle screws as the nonfractured endplate and immobilized disc (NFEID), and the IVD that has no endplate fracture and no immobilization instrumentation as the normal disc (ND). At 2 years after implant removal, magnetic resonance imaging (MRI) was performed again for comparison. The extent of disc degeneration was classified using the Pfirrmann classification system. RESULTS: FEIDs were present in 67 levels, NFEIDs in 78 levels, and NDs in 114 levels. According to the Pfirrmann classification, 7.9% of the NDs, 32.1% of the NFEIDs, and 43.3% of the FEIDs were more degenerated at 2 years after implant removal. The FEIDs and NFEIDs were more degenerated than the NDs and the FEIDs were more degenerated than the NFEIDs at statistically significant levels (p < 0.001 for both). CONCLUSIONS: Spine immobilization with transpedicular screws has a significant influence on disc degeneration, and an endplate fracture accelerates the degeneration process.
Classification ; Humans ; Immobilization ; Intervertebral Disc ; Intervertebral Disc Degeneration ; Magnetic Resonance Imaging ; Pedicle Screws ; Spine

STUDY DESIGN: Case-control study (retrospective comparative study). OBJECTIVES: The purpose of this study was to define the relationship between low back pain (LBP) and the cross-sectional area (CSA) and density of the erector spinae muscle (ESM) and isolated multifidus muscle (IMM) on computed tomography (CT) scans of patients with a chief complaint other than LBP. SUMMARY OF LITERATURE REVIEW: Most previous studies have focused on radiographic data from patients with a chief complaint of LBP, rather than on radiographic data from patients with a chief complaint other than LBP. MATERIALS AND METHODS: This retrospective study included 475 patients who underwent CT scans between January 1, 2010 and December 31, 2010. The CSA and density of the ESM, IMM, and the psoas muscle (PM) were obtained. All measurements were calculated as the ratio of each muscle. The relationships between the CSA of each muscle and both types of LBP were analyzed. RESULTS: The ESM-to-PM ratio in terms of density was 1.227±0.797 in the LBP group and 0.645±0.732 in the non-LBP group (p=0.174). The IMM-to-PM ratio in terms of density was 0.664±0.515 in the LBP group and 0.806±0.518 in the non-LBP group (p=0.007). CONCLUSIONS: The IMM was more relevant to LBP than the ESM of the back, and density was more relevant to LBP than the CSA of regular muscles. The IMM was more useful than the ESM for analyzing LBP.
Case-Control Studies ; Humans ; Low Back Pain* ; Muscles ; Paraspinal Muscles* ; Psoas Muscles ; Retrospective Studies ; Tomography, X-Ray Computed

BACKGROUND: Although pedobarographic measurement is increasingly used for clinical and research purposes, relatively few published studies have investigated normative data. This study examined pedobarographic findings in young healthy adults with regard to sex-related differences and correlations among measurement indices. METHODS: Twenty young healthy adults (mean age, 22.4 years; standard deviation, 1.2 years; and 10 males and 10 females) were included. Weight bearing anteroposterior (AP) and lateral foot radiographs were taken, and dynamic pedobarographic data during treadmill walking and maximum ankle dorsiflexion were obtained. AP talo-first metatarsal angle, naviculocuboid overlap, lateral talo-first metatarsal angle, and plantar soft tissue thickness were measured on foot radiographs. Pedobarographic data including peak pressure and pressure-time integral were measured on five plantar segments: medial forefoot (MFF), lateral forefoot (LFF), medial midfoot (MMF), lateral midfoot (LMF), and heel. RESULTS: Male and female subjects significantly differed in body mass index (BMI, p < 0.001), AP talo-first metatarsal angle (p = 0.018), soft tissue thickness under the metatarsal head (p = 0.040) and calcaneal tuberosity (p < 0.001), maximum dorsiflexion during stance phase (p = 0.041), peak pressure on the MFF (p = 0.005) and LFF (p = 0.004), and pressure-time integral on the MFF (p = 0.018) and heel (p = 0.001). BMI was significantly correlated with soft tissue thickness under the metatarsal head (r = 0.521, p = 0.018) and calcaneal tuberosity (r = 0.585, p = 0.007), peak pressure on the MFF (r = 0.601, p = 0.005) and LFF (r = 0.487, p = 0.029), pressure-time integral on the heel (r = 0.552, p = 0.012), and total pressure-time integral (r = 0.755, p < 0.001). Maximum dorsiflexion demonstrated significant negative correlations with pressure-time integral on the MFF (r = −0.595, p = 0.007) and total pressure-time integral (r = −0.492, p = 0.032). Pressure-time integral varus/valgus index was significantly correlated with pressuretime integral forefoot/heel index (r = 0.472, p = 0.036). CONCLUSIONS: Sex-related differences in pedobarographic examination were observed, which could provide useful information in setting appropriate treatment goals and obtaining appropriate control data. The effects of subtalar motion in distributing plantar pressure should be investigated in a future study.
Adult* ; Ankle ; Body Mass Index ; Female ; Foot ; Head ; Heel ; Humans ; Male ; Metatarsal Bones ; Sex Characteristics* ; Walking ; Weight-Bearing

PURPOSE: Anti-vascular endothelial growth factor (VEGF) agents have been used for the last 10 years, but their safety profile, including cytotoxicity against various ocular cells such as retinal pigment epithelial (RPE) cells, remains a serious concern. Safety studies of VEGF agents conducted to date have primarily relied on healthy RPE cells. In this study, we assessed the safety of three anti-VEGF agents, namely, ranibizumab, bevacizumab, and aflibercept, on senescent RPE cells. METHODS: Senescent human induced pluripotent stem cell-derived RPE cells were generated by continuous replication and confirmed with senescence biomarkers. The viability, proliferation, protein expression, and phagocytosis of the senescent RPE cells were characterized 3 days after anti-VEGF treatment with clinical doses of ranibizumab, bevacizumab, or aflibercept. RESULTS: Clinical doses of ranibizumab, bevacizumab, or aflibercept did not decrease the viability or alter proliferation of senescent RPE cells. In addition, the anti-VEGF agents did not induce additional senescence, impair the protein expression of zonula occludens-1 and RPE65, or reduce the phagocytosis capacity of senescent RPE cells. CONCLUSIONS: Clinical dosages of ranibizumab, bevacizumab, or aflibercept do not induce significant cytotoxicity in senescent RPE cells.
Aging ; Bevacizumab* ; Biomarkers ; Endothelial Growth Factors ; Epithelial Cells* ; Humans ; Phagocytosis ; Ranibizumab* ; Retinaldehyde* ; Vascular Endothelial Growth Factor A

Background: This study aimed to compare the biomechanical strength of 360° scapholunate interosseous ligament (SLIL) reconstruction only using an artificial material (AM), double dorsal limb (DDL) SLIL reconstruction only using AM, and the modified Brunelli technique (MBT) with ligament. Methods: Eight cadaver wrists were used for this study. The SL interval, SL angle, and radiolunate (RL) angle were recorded with MicroScribe. The SL distance was measured after dividing the volar and dorsal aspects. We utilized four different wrist postures (neutral, flexion, extension, and clenched fist) to compare five conditions: intact wrist, SLIL resection, 360° SLIL reconstruction using AM, DDL SLIL reconstruction using AM, and MBT SLIL reconstruction with ligament. Results: The dorsal SL distance in the SLIL resection was widened in all wrist positions. The dorsal SL distance was restored with all three techniques and in all wrist positions. The volar SL distance in the wrist extension position was widened in the SLIL resection condition. The volar SL distance was restored in the extension position after 360° SLIL reconstruction using AM condition. There were no statistically significant differences in SL and RL angles among the conditions. Conclusions All three reconstruction techniques could restore the dorsal SL distance. However, only the 360° SLIL reconstruction using AM restored the volar SL distance in the wrist extension position. DDL SLIL reconstruction using AM tended to overcorrect, whereas 360° SLIL reconstruction using AM effectively stopped volar SL interval widening.