Paraaortic dissection in “total mesopancreas excision” and “mesopancreas-first resection” pancreaticoduodenectomies for pancreatic cancer: Useless,optional, or necessary?A systematic review

The mesopancreas does not have well-defined boundaries but is continuous and connected through its components with the paraaortic area. The mesopancreatic resection margin has been indicated as the primary site for R1 resection after PD in pancreatic head cancer and total mesopancreas excision has been proposed to achieve adequate retropancreatic margin clearance and to minimize the likelihood of R1 resection. However, the anatomy of the mesopancreas requires extended dissection of the paraaortic area to maximize posterior clearance. The artery-first surgical approach has been developed to increase local radicality at the mesopancreatic resection margin. During PD, the artery-first approach begins with dissection of the connective tissues around the SMA. However, the concept of the mesopancreas as a boundless structure that includes circumferential tissues around the SMA, SMV, and paraaortic tissue highlights the need to shift from artery-first PD to mesopancreas-first PD to reduce the risk of R1 resection. From this perspective the “artery-first” approach, which allows for the avoidance of R2 resection risk, should be integrated into the “mesopancreas-first” approach to improve the R0 resection rate.In total mesopancreas excision and mesopancreas-first pancreaticoduodenectomies, the inclusion of the paraaortic area and circumferential area around the SMA in the resection field is necessary to control the tumour spread along the mesopancreatic resection margin rather than to control or stage the spread in the nodal basin.     

The relationship between ankle dorsiflexion range of motion,frontal plane projection angle,and patellofemoral pain syndrome

BackgroundAnkle range of motion abnormalities have been often linked with alteration in knee kinematics leading to the development of patellofemoral pain syndrome (PFPS). Literature exploring the relationship between ankle dorsiflexion range of motion (DF ROM) and knee kinematics during functional tasks is scanty. This study aims to assess the relation between ankle DF ROM and frontal plane projection angle (FPPA), one of the knee kinematic variables, in individuals with and without PFPS during a step-down test.MethodsThis is a case-control study in which seventy PFPS patients and other 70 asymptomatic control subjects had their ankle DF ROM measured using an inclinometer with the knee flexed and extended. Their FPPA angles were measured using Kinovea software while doing the step-down test.ResultsWhen the two groups were compared, ankle DF ROM measured with the knee flexed was higher in the control group (33.15 ± 4.96) than in the PFPS group (30.20 ± 6.93) (p = 0.03). In both the PFPS group and the control group, the correlation between FPPA and ankle DF ROM with the knee flexed was statistically insignificant (p = 0.075 and 0.323 respectively).ConclusionDecreased ankle DF ROM can be one of the contributing factors to the development of PFPS in the context of greater dynamic knee valgus.     

外侧半月板后根部损伤不同缝合位置对膝关节生物力学的影响

目的对损伤的外侧半月板后根部进行不同位置的修复固定,比较不同缝合方式时膝胫股关节的生物力学结果,探讨外侧半月板后根部损伤最佳缝合术式。方法使用8例人体尸体膝关节,胫腓骨固定装置维持膝关节在0°位,在1 k N压缩载荷下,采用Tek-scan压力感测片收集膝关节外侧半月板后根部完整、外侧半月板后根部断裂、将外侧半月板后根部分别缝合至中心点、中心点偏后5 mm、中心点偏前5 mm、中心点偏外5 mm位置下的平均接触压力、峰值压力以及接触面积。结果在外侧间室,与完整状态相比半月板后根部损伤断裂后会导致平均接触压力和峰值压力明显增加(P0. 01),接触面积减少(P0. 05)。4种缝合固定方法均可减少平均压力和峰值接触压力,接触面积较根部断裂时均有增加。在半月板后根部中心点偏外5 mm缝合时,生物力学结果更接近完整膝关节(P0. 05)。比较缝合位点在根部中心点和中心点偏后5 mm时,平均接触压力影响差别微小,峰值接触压力、接触面积均无统计学差异(P0. 05)。在内侧间室,生物力学指标各组间均无统计学差异(P0. 05)。结论外侧半月板后根部发生撕裂后会导致膝关节外侧间室的平均接触压力、峰值压力以及接触面积相比正常膝关节发生显著改变;半月板缝合位置在原根部中心点偏外5 mm时,其生物力学功能更接近完整膝关节。     

Comparison of increased overjet cases and controls: normative data for condylar positions

The aim was to compare normal overjet versus large overjet cases with clinically healthy temporomandibular joints (TMJ); to establish normative data regarding the difference between condylar positions in centric occlusion (CO) and maximum intercuspation (MI) and deflective CO contacts. Two study groups of normal overjet and large overjet cases consisted each of 33 subjects with no detectable clinical signs of temporomandibular disorder (TMD). CO-MI differences were recorded using the SAM Mandibular Position Indicator. Deflective contacts were examined on models mounted in CO. There was a significant difference between groups in the vertical (P = 0.030) and transverse (P = 0.008) range of movement from CO to MI, but not in the antero-posterior direction. There were no differences in the location of deflective contacts. Results of this study showed that patients with increased overjet show some differences compared with normal overjet patients, even in the non-patients. Further research on TMD patients is needed to find out about the role these features play in the aetiology and treatment of temporomandibular disorder (TMD). This study indicates that the clinician should be paying special attention to the TMJ status of patients with a large overjet.     

Influence of the inclination of the plate of an intra-oral tracing device on the condylar position registered by tapping movement

The object of this study was to determine the best inclination of the intra-oral tracing device to get optimum condylar position with the registration of tapping movement. Three appliances with different tracing plate inclinations were used in five healthy subjects. The tracing plates were set at 0 degrees to occlusal plane (horizontal); at the angle formed by drawing a line from condylar point to the stylus position at occlusal plane (inclined); then at the angle half to inclined (half-inclined). Subjects made Gothic arch and tapping movements (n = 30) at a 30 mm interincisal distance with the head Camper plane horizontal. The incisal and condylar points were tracked with a 6-degree-of-freedom jaw movement tracking system. The location of gothic arch apex, the distribution and mean position of 30 tapping points from intercuspal position were analyzed in incisal and condylar point between the appliances. Data were analyzed with repeated measures one-way anova. Results showed that mean position of tapping points were significantly different among the appliances. Half-inclined appliance recorded tapping points in a convergent area nearer to intercuspal position (IP) than other appliances. In all appliances, the contact points of the tapping movement were anterior to Gothic arch apex.     

正常汉族成年人前牙区牙槽宽度及根尖位置的研究

目的研究正常[牙合]成人前牙根尖与周围骨皮质的位置关系，为正畸矫治设计、筛选根吸收高危人群和预防医源性并发症等提供指导。方法选择正常拾青年98人，男女各半，年龄范围17～25岁，平均年龄20．29岁。拍摄头颅侧位定位片，测量并计算反映上下颌切牙根尖到周围骨皮质位置关系的12项指标及下颌平面角。建立上述测量指标的均值范围；相关分析研究下颌平面角对其影响。结果（1）建立正常[牙合]男女根尖位置及牙槽宽度的均值。（2）男性组中SN／MP与UH、UH／UW正相关，与UP负相关；女性组中SN／MP与LW负相关。结论（1）正常汉族成年人上下颌前牙牙槽骨宽度及根尖相对皮质骨位置比较稳定。（2）下颌平面角对根尖位置及牙槽宽度有一定影响。     

Prosthodontic procedures for implant reconstruction. 1. Diagnostic procedures

The University of Sydney Dental School and more recently the Implant Centre have been treating patients with the Brånemark Osseointegration Implant System since 1981. Success depends on close cooperation between surgeon and prosthodontist. This paper describes specific prosthodontic treatment planning procedures based on a general knowledge of prosthodontics, and detailed methods for determining the position, length and alignments of the implants for a specific case by the use of radiographic and surgical templates.     

TMJ symptoms reduce chewing amplitude and velocity,and increase variability

Objective: The null hypothesis was that mandibular amplitude, velocity, and variability during gum chewing are not altered in subjects with temporomandibular joint (TMJ) internal derangements (ID).

Methods: Thirty symptomatic subjects with confirmed ID consented to chew gum on their left and right sides while being tracked by an incisor-point jaw tracker. A gender and age matched control group (p > 0.67) volunteered to be likewise recorded. Student’s t-test compared the ID group’s mean values to the control group.

Results: The control group opened wider (p < 0.05) and chewed faster (p < 0.05) than the ID group. The mean cycle time of the ID group (0.929 s) was longer than the control group (0.751 s; p < 0.05) and more variable (p < 0.05).

Discussion: The ID group exhibited reduced amplitude and velocity but increased variability during chewing. The null hypothesis was rejected. Further study of adaptation to ID by patients should be pursued.     

斜侧入路体位摆放预防甲状腺手术体位综合征的效果

目的：评估斜侧入路手术体位摆放预防甲状腺手术体位综合征的效果。方法：回顾性分析2019年6月至2019年12月温州医科大学附属第一医院甲乳外科行甲状腺手术的患者,分为传统手术组（132例）和斜侧入路手术组（81例）,观察两组患者手术体位综合征的发生情况,同时观察两组患者术中情况,包括切口长度、失血量、手术时间、术野暴露质量等指标。结果：传统手术组与斜侧入路手术组患者性别（33/99 vs.20/61,P =1.000）、年龄[（52.4±9.4）岁 vs.（ 51.5±10.2）岁,P =0.546]、失血量[（16.80±2.64）mL vs.（16.72±2.61）mL,P =0.815）和手术时间[（64.25±5.45）min vs.（ 63.00±6.58）min,P =0.135]差异均无统计学意义;与传统手术组相比,斜侧入路手术组患者在不延长手术时间的前提下,其切口更短[（6.47±0.78）cm vs.（ 4.93±0.32）cm,P＜0.001],手术体位综合征发生更少（耐受差发生率42.4% vs. 16.0%,P＜0.001;头痛61.4% vs. 24.7%,P ＜0.001;恶心呕吐49.2% vs. 17.3%,P ＜0.001）,术野暴露质量更佳（1级暴露率49.2% vs. 72.8%,P =0.001）。结论：斜侧入路手术体位摆放使手术体位从头部极度后仰改善到头部稍后仰,能有效减少甲状腺手术体位综合征的发生,是一种安全可行的方法。