寰枢椎后路柔性固定的生物力学研究

目的分析细棒、PEEK棒固定对寰枢关节稳定性的影响。方法采用6具新鲜成人枕骨(occipital bone,Oc)~颈椎C4节段进行测试,模拟以下手术及固定状态:①完整状态;②损伤状态:枢椎齿状突II型骨折;③坚强固定:寰枢椎均采用普通椎弓根螺钉固定,直径3.5 mm钛棒连接;④PEEK棒:直径3.5 mm的PEEK棒连接;⑤细棒:直径2.0 mm钛棒连接。采用重复测量实验设计,在完整、损伤和不同的固定状态下,通过脊柱试验机对标本分别施加1.5 N·m的前屈/后伸、左/右侧弯和左/右轴向旋转的纯力偶矩。采用Optotrak三维运动测量系统连续采集标本运动,分析寰枢椎之间角度运动范围和中性区。结果采用直径3.5 mm的钛棒,2.0 mm的细棒以及3.5 mm的PEEK棒固定后,在前屈、后伸、侧弯和旋转方向上均显著减小了固定节段的运动范围(P<0.05)。直径3.5 mm和2.0 mm的棒固定后的运动范围,在各个方向上无显著性差异。PEEK棒固定的运动范围仅在侧弯方向上大于坚强固定(P=0.005),其他方向无显著性差异。3种固定方式在屈伸、侧弯和旋转方向上均显著减小了固定节段的中性区(P<0.05)。各种固定方式之间相比较,无显著性差异(P>0.05)。结论在寰枢关节采用直径2.0 mm的细棒固定,与坚强固定的稳定性相当。采用直径3.5 mm的PEEK棒固定,在前屈、后伸、旋转方向上与坚强固定的稳定性相当,在侧弯方向上弱于坚强固定。     

Polarity-specific high-definition transcranial direct current stimulation of the anterior and posterior default mode network improves remote memory retrieval

BackgroundPrevious studies show that activity in the posterior default mode network (pDMN), including the posterior cingulate cortex and the precuneus, is correlated with the success of long-term episodic memory retrieval. However, the role of the anterior DMN (aDMN) including the medial prefrontal cortex is still unclear. Some studies show that activating the medial prefrontal cortex improves memory retrieval while other studies show deactivation of the medial prefrontal cortex in successful retrieval of episodic memories, suggesting a possible functional dissociation between the aDMN and pDMN.ObjectiveIn the current study, we aim to causally explore this probable dissociation using high-definition transcranial direct current stimulation (HD-tDCS).MethodsWe perform a randomised double-blinded two-visit placebo-controlled study with 84 healthy young adults. During Visit 1 they learn 75 Swahili-English word-associations. Seven days later, they randomly receive either anodal, cathodal or sham HD-tDCS targeting the pDMN or aDMN while they recall what they have previously learned.ResultsWe demonstrate that anodal stimulation of the pDMN and cathodal stimulation of the aDMN, equally improve the percentage of Swahili-English word-associations recalled 7 days after learning.ConclusionsModulating the activity in the aDMN and pDMN causally affect memory retrieval performance. HD-tDCS of the aDMN and pDMN shows that anodal stimulation of the pDMN and cathodal stimulation of the aDMN increases memory retrieval performance one week after the learning phase. Given consistent evidence, it is highly likely that we are increasing the activity in the pDMN with anodal pDMN stimulation. However, it is not clear if cathodal HD-tDCS targetting aDMN works via decoupling from the pDMN or via indirectly disinhibit pDMN.     

Importancia de algunos aspectos técnicos del procedimiento de estimulación percutánea del nervio tibial posterior en pacientes con incontinencia fecal

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显微血管减压术治疗舌咽神经痛的临床疗效分析

目的探讨显微血管减压术(MVD)治疗舌咽神经痛(GPN)的安全性及远期临床疗效。方法回顾性分析39例行显微血管减压术治疗的舌咽神经痛患者的临床资料。所有患者均采用乙状窦后-幕下入路进行显微血管减压手术,术后定期随访。结果所有患者术后早期疗效显著,随访时间为1~9年,平均为4.9年。随访过程中1例患者术后2年出现舌咽神经痛症状复发,1例患者术后1.5年舌咽神经痛症状部分复发。术后出现声音嘶哑及吞咽困难患者4例、脑脊液漏患者1例,均在随访过程中恢复。结论显微血管减压术是治疗舌咽神经痛安全有效且远期效果良好的方法,术前影像学检查对于责任血管的判断有重要意义。     

关节镜双后内入路与切开手术治疗急性单纯后交叉韧带胫骨止点撕脱骨折早期疗效对比

目的:比较关节镜双后内入路与切开手术治疗急性单纯后交叉韧带胫骨止点撕脱骨折的疗效差异。方法:回顾性分析2016年6月至2020年6月经手术治疗的52例急性单纯性后交叉韧带胫骨止点撕脱骨折患者的临床资料,按手术方案不同分为两组,关节镜组27例患者行关节镜双后内入路手术治疗,其中男16例,女11例,年龄19~52(34.9±9.2)岁;切开复位组25例患者行膝关节后内侧切口手术治疗,其中男14例,女11例,年龄18~54(33.7±8.4)岁。观察并比较两组患者手术时间、切口长度、术中出血量、住院时间、住院费用、术后愈合情况、并发症以及术后12个月Lysholm、IKDC评分。结果:两组患者均顺利完成手术,无血管、神经损伤。52例均获得随访,时间6~24(15.0±1.7)个月。关节镜组手术时间、住院费用大于切开复位组(P<0.05);关节镜组术中出血量、切口长度、住院时间小于切开复位组(P<0.05);关节镜组和切开复位组术后12个月Lysholm评分分别为(95.9±1.7)分和(86.4±1.2)分,均较术前的(49.1±2.3)分和(48.9±1.1)分显著提高(P<0.05);关节镜组和切开复位组术后12个月IKDC总分分别为(96.9±1.5)分和(87.1±1.4)分,均较术前的(47.6±4.1)分和(48.1±3.9)分显著提高(P<0.05);关节镜组术后12个月膝关节Lysholm、IKDC评分均高于切开复位组(P<0.05)。结论:关节镜双后内入路治疗急性单纯后交叉韧带胫骨止点撕脱骨折,早期效果满意,疗效优于传统开放手术,具有创伤小、恢复快、操作简便等优点。     

Anatomical alterations following the ‘PSARP’ procedure: Correlating MRI findings with continence scores

Purpose

To identify anatomical aberrations following PSARP procedure by using MRI, while correlating MRI findings to clinical outcome.

Terminology of Peters’ anomaly variants: Summary of histopathological findings in 6 corneas and detailed clinicopathological correlation in 2 cases

Peters’ anomaly accounts for the highest type of Anterior Segment Dysgenesis (ASD). The main features of Peters’ anomaly are: congenital corneal opacity centrally, defect in the posterior stroma and absence of Descemet’s membrane and the endothelium. However, this condition has wide clinical and histopathological variations in appearance, associations and severity. In this case series, we summarize 6 corneas in 5 Saudi cases of Peters’ anomaly (and describe 2 in detail) with unique histopathological findings that are additional to the typical known ones, shedding some light on the nomenclature of these variants according to the reported cases in the English-written literature. This will widen the spectrum of findings known to ophthalmic pathologists and ophthalmologists about this anomaly. This is also of importance in the assessment of the congenital glaucoma cases commonly seen in Saudi Arabia that often happens in association with ASD.     

Posterior approaches to the ankle – an analysis of 3 approaches for access to the posterior malleolar fracture

BackgroundAn anatomical study to determine what degree of access to the posterior distal tibia could be gained by using 3 different approaches; the posterolateral, the posteromedial and the medial posteromedial approaches.MethodsA comparison study, between the anatomical dissection of 7 fresh frozen cadaveric lower legs and image analysis of CT data of posterior malleolar fractures from a prospectively collected database was conducted. All fractures have been classified using the Mason and Molloy classification.ResultsIn comparing the posterior malleolar fracture fragment width to distal tibia width, the posterolateral fragment encompasses 60.1% (95% CI 56.8, 63.3) of the total width of the tibia. If the posteromedial fragment is included the fragments encompass the entire distal tibia (100%). In type 3 fractures, 81.4% (95% CI 75.5, 87.1) of the distal tibia width is involved.When comparing the fracture width to the approach, no approach achieves a complete exposure of the type 2B or 3 fracture patterns. The overall surface area of the type 2B and 3 fractures, is significantly greater than all the approaches. Considering the lateral to medial extent of the fracture, the posterolateral fragment mean width is 33% greater than what can be exposed by the posterolateral approach (mean 24.9 vs 16.8 mm). In type 2B and 3 fractures, the horizontal exposure reduces to 39.8% and 47.6% respectively. In comparison, the PM approach exposes 47.6% of the type 2B fracture pattern and 57.1% of the type 3 fracture pattern and allows a preferable angle for hardware insertion. The MPM approach does not expose any of the posterolateral fragments in this study, however it does expose 92% (mean 21.9 vs. 23.8 mm) of the medial to lateral width of a posteromedial fragment of a type 2B fracture.ConclusionEach approach allows access to different parts and amounts of the posterior tibia. An understanding of and utilisation of these approaches can lead to adequate exposure for fixation of most posterior malleolus fracture patterns seen.