不同弯曲度根管中两种分离器械取出成功率对比研究

目的：体外对比分析不同弯曲度根管中分离的镍钛器械和不锈钢器械取出的成功率。方法：取新鲜拔除的离体人牙60颗,随机分为镍钛器械组和不锈钢器械组,每组30颗牙,分别将机用镍钛根管锉和不锈钢K锉分离于三种不同弯曲程度的根管内,根管显微镜下超声法取出分离器械,计算取出成功率并统计学分析。结果：不锈钢器械取出率高于镍钛器械,但差异无统计学意义（P〉0．05）。直根管和轻度弯曲根管中两种分离器械的取出成功率差异无显著统计学差异（P〉0．05）。重度弯曲根管中两种分离器械的取出成功率明显低于直根管和轻度弯曲根管的取出成功率,差异有显著统计学意义（P〈0．05）。结论：显微超声法可有效取出不同弯曲度根管内分离的镍钛和不锈钢器械。根管弯曲度是根管内分离器械取出的关键因素,对于重度弯曲根管内分离器械的取出进行术前的合理评估。     

Cervical curvature, spinal cord MRIT2 signal, and occupying ratio impact surgical approach selection in patients with ossification of the posterior longitudinal ligament

Objective

Factors impacting surgical options and outcomes in patients with cervical ossification of the posterior longitudinal ligament (OPLL) were explored.

Methods

A retrospective analysis was conducted of 127 eligible cervical OPLL patients (61 males, 66 females) aged 41–70 years (mean 55.2 years) selected from 152 total OPLL patients treated from 2002 to 2006, with 5–10-year (mean 6.8 years) follow-up. Patients underwent anterior subtotal corpectomy with ossification ligament resection (anterior surgery, n = 68) or posterior cervical double-door laminoplasty (posterior surgery, n = 59). Radiographic assessments of cervical curvature, T2-weighted MRI (MRIT2) signal, and OPLL occupying ratio were correlated with surgical strategy before surgery and at 1, 5 weeks, and 5 years.

Results

Lordosis increased following anterior surgery, though kyphosis improved by 10.3 %. The canal stenosis occupying ratio was >50 %, and short-term improvement following anterior surgery was significantly higher than posterior surgery (P > 0.0001). Superior neurological function was observed in patients with unchanged versus high spinal MRIT2 signals (P = 0.0434). No significant differences were observed in short-term outcomes between anterior and posterior surgeries in high spinal MRIT2 signal patients, but anterior surgery produced significantly better long-term outcomes at 1 week (P = 0.7564) and 1 year (P = 0.0071). Complications occurred in five anterior and three posterior surgeries.

Conclusion

Preoperative assessment of cervical curvature, MRIT2 signal, and occupying ratio can be used to guide clinical surgical approach selection to potentially produce better long-term outcomes in patients with OPLL.     

两种胸腰椎压缩骨折复位手术的比较

[摘要]目的探讨伤椎植钉曲度矫正在胸腰椎压缩骨折复位术的效果。方法胸腰椎压缩骨折患者52例,随机分为两组,常规组26例单纯行后路钉棒复位内固定,实验组26例行后路钉棒复位内固定、伤椎植入椎弓根螺钉C臂X线机下进行曲度矫正。比较两组腰背痛VAS评分和ODI评分,测量和计算脊柱曲度Cobb角、伤椎椎体高度百分比及椎间隙高度;比较内固定系统松动及断裂情况,对脊髓损伤分级进行评估。结果两组比较,实验组术后末次随访时VAS和ODI评分均优于常规组（P〈0．叭或P〈0．05）;术后即刻两组Cobb角、伤椎椎体高度百分比及椎间隙高度比较无统计学差异（P〉0．05）,但术后末次随访时实验组较常规组显著改善（P〈0．01或P〈0．05）;实验组术后脊髓功能Frankel分级明显优于常规组（JP〈O．05）,且术后背痛、椎间盘退变加速、钉道松动、钉棒系统断裂及曲度不良等并发症较常规组显著减少（P〈0．叭或P〈0．05）。结论胸腰椎压缩骨折钉棒复位内固定术中行伤椎植钉曲度矫正后手术疗效较好,术后并发症明显减少,患者脊髓损伤得到显著改善。     

Reliability of assessing the coronal curvature of children with scoliosis by using ultrasound images

Purpose

To investigate the intra- and inter-observer reliability of the coronal curvature asymmetry of children with adolescent idiopathic scoliosis (AIS) using the center of lamina (COL) method on ultrasound (US) images.

Methods

A cadaver spinal column phantom which was manipulated to present 30 scoliotic curves of varying severity of scoliotic deformities was scanned using both the US and laser scanner (LS) systems. Three observers of varying experience and skill measured the coronal curvature using the Cobb method on the LS images and the COL method on the US images. All of the measurements were performed twice, with a 1-week interval to reduce memory bias. The intra-class correlation coefficient (ICC), the mean absolute differences (MAD), and the error index (EI) were calculated to determine the agreement on selecting the end vertebrae. In addition, five AIS subjects were scanned using the US system. One observer measured the coronal curvature on the US images twice, and the measurements were compared with the Cobb angle reported in the clinical records.

Results

In the phantom study, the COL method showed high intra- and inter-observer reliabilities, with all ICC values >0.88. The maximum MAD of the COL measurements between different sessions among all observers was <4.1°. The EI values of the US method had similar end-vertebra selections as the LS method. The results of the pilot study showed a high intra-reliability for the US measurements. The measured difference between the Cobb and COL methods was 0.7° ± 0.5°.

Conclusions

The COL method using US images appears to be a very reliable method for measuring the coronal curvature in AIS without the need to expose the patient to radiation.     

LncRNA SNHG15 predicts poor prognosis in uveal melanoma and its potential pathways

AIM: To evaluate the inter-device agreement of corneal curvature between Pentacam and a swept-source Fourier-domain anterior segment optical coherence tomography (AS-OCT) in ectopia lentis patients. MethodS: Totally 72 eyes from 72 ectopia lentis patients were recruited. Central corneal thickness (CCT), corneal curvature values and corneal astigmatism were obtained from both the Pentacam and AS-OCT (CASIA2). Repeatability was evaluated for both devices. The coefficient of repeatability (COR) and the relative COR was calculated. Bland-Altman plots were performed to assess the inter-device agreement of measurement. Orthogonal linear regression was used to assess any proportional bias. Results: The mean difference of CCT, flat anterior corneal curvature (anterior Kf), steep anterior corneal curvature (anterior KS), anterior corneal astigmatism (ACA), flat posterior corneal curvature (posterior Kf), steep posterior corneal curvature (posterior KS), posterior corneal astigmatism (PCA), flat true net power (TNP Kf), steep true net power (TNP KS) and total corneal astigmatism (TCA) between Pentacam and CASIA2 were 7.03±9.70 μm, -0.27±0.35 D, -0.19±0.41 D, 0.04±0.47 D, -0.11±0.11 D, -0.17±0.23 D, -0.02±1.02 D -0.52±0.46 D, -0.41±0.43 D, and -0.15±0.96 D, respectively. For measurement of TNP Kf with the Pentacam and CASIA2, a mean difference of 0.52 D and COR of 0.90 with P=0.020 was detected. There was no significant difference in CCT (P=0.393), anterior Kf (P=0.107), anterior Ks (P=0.414), ACA (P=0.131), posterior Kf (P=0.286), posterior Ks (P=0.418), PCA (P=0.105), TNP Ks (P=0.054), and TCA (P=0.977) between Pentacam and CASIA2. Conclusion: Our study indicates generally good agreement of CCT, corneal curvature and corneal astigmatism measurement by the Pentacam and CASIA2 in ectopia lentis patients. However, there was significant difference for CCT and corneal curvature values obtained by the two devices.     

Evaluation of the Cyclic Fatigue of Two Single Files at Body and Room Temperature with Different Radii of Curvature

Background: To compare the influence of different temperatures and curvature radii on the cyclic fatigue resistance of F6 SkyTaper (F6ST) and One Curve (OC) single file nickel-titanium rotary instruments. Methods: A total of 120 instruments of F6ST and OC #25.06 were evaluated in 5 mm and 3 mm curvature radii at two temperatures (20 °C ± 1 °C and 37 °C ± 1 °C) in 16 mm stainless steel artificial canals associated with a curvature of 60°. The cyclic fatigue of tested files was assessed by employing a customized testing apparatus and expressed as times to fracture (TtF). A statistical analysis was performed with the significance level set at 95%. Results: All instruments decreased their TtF at 37 °C except for OC in the 3 mm radius, in which no significant difference was detected between 20 °C and 37 °C. A 3 mm curvature radius negatively affected TtF of all tested instruments, except for F6ST at 20 °C. F6ST had higher TtF than OC in the 3 mm radius at 20 °C, with no significant difference between them in the other tested conditions. Conclusions: Under the limits of the present in vitro study, body temperature impaired cyclic fatigue resistance of all files, except for OC in the 3 mm curvature radius. All instruments exhibited lower times to fracture in the 3 mm radius, excluding F6ST at 20 °C.     

Curvature-processing network in macaque visual cortex

Our visual environment abounds with curved features. Thus, the goal of understanding visual processing should include the processing of curved features. Using functional magnetic resonance imaging in behaving monkeys, we demonstrated a network of cortical areas selective for the processing of curved features. This network includes three distinct hierarchically organized regions within the ventral visual pathway: a posterior curvature-biased patch (PCP) located in the near-foveal representation of dorsal V4, a middle curvature-biased patch (MCP) located on the ventral lip of the posterior superior temporal sulcus (STS) in area TEO, and an anterior curvature-biased patch (ACP) located just below the STS in anterior area TE. Our results further indicate that the processing of curvature becomes increasingly complex from PCP to ACP. The proximity of the curvature-processing network to the well-known face-processing network suggests a possible functional link between them.Decades of research have focused on understanding visual feature processing, particularly along the ventral visual pathway. Such studies have shown that neurons in lower-order visual areas (e.g., V1) respond strongly to simple oriented contours (1), whereas neurons in higher-order visual areas (e.g., inferior temporal cortex) respond selectively to more complex image features and/or visual categories (2–4), in ways that are not yet fully understood. To link these extremes in visual information processing, many studies have aimed to clarify the optimal “trigger” features at intermediate levels of the visual cortical hierarchy.Among these features, stimulus curvature has not been well studied. This is surprising because, strictly, all lines are curved to some extent, except for the single exception of a perfectly straight line. This ubiquity of curved shapes also extends to 3D surfaces (5). In nature, where much of our visual system presumably evolved, perfectly flat surfaces are rare. Even the flattest of natural features (e.g., oceans, sandy beaches) are often curved to some extent, due to wind, water motion, and even the curvature of the earth. Thus, it is important to understand curvature processing to fully unravel the steps in cortical visual processing.Among the few studies to test single neuron responses to curvature per se, Gallant et al. (6, 7) reported that a significant percentage of neurons in macaque cortical area V4 is selective for curved stimuli. Intriguingly, these authors also noted that neurons preferring curved patterns were often anatomically clustered together. Subsequently, Pasupathy and Connor (8–10) demonstrated that neurons in the parafoveal representation of dorsal V4 respond robustly to the curvature component of complex shapes. To our knowledge, there have been no systematic studies of curvature at levels below V4 in macaques.Intriguingly, some evidence suggests that the processing of curvature may interact selectively with the processing of faces. For instance, perceptual deficits in face recognition (prosopagnosia) are sometimes associated with deficits in curvature discrimination (11). In addition, some neurons in face-selective regions of the temporal lobe also respond to rounded nonface objects (12, 13). A human functional magnetic resonance imaging (fMRI) study (14) reported that a concentrically curved grating produced a larger response in the fusiform face-selective area (FFA) (15, 16), compared with an otherwise identical linear grating.Here, we tested for a cortical specialization of curvature processing, using fMRI in fixating macaque monkeys. Given the previous single-unit studies (6–10), we expected that curved stimulus features would activate V4, either in specific patches or distributed throughout the area. The present fMRI approach also allowed us to test whether curvature processing is confined to V4, or whether it extends into additional brain regions. If specialized areas for curvature processing were identified, we could then ask whether they might be topographically linked with face-selective regions. Such an arrangement would shorten the mean axonal length between curvature- and face-processing regions, if these regions were functionally related.