Impact of drying and thiel embalming on mechanical properties of achilles tendons

Biomechanical research and orthopedic training is regularly carried out on human cadavers. Given the post‐mortem decay, these cadavers were usually frozen or embalmed. The embalming method according to Dr. Thiel was often praised for the preservation of natural texture. The main aim of this article was to quantitatively analyze the impact of this embalming technique on the biomechanical properties. To that extent, Achilles tendons (calcaneal tendons) of seven cadavers have been tested. For each cadaver, a first tendon was tested following a fresh‐frozen conservation, the other following the Thiel embalming process. The results indicated a significant difference in Young's modulus between both groups (P values = 0.046). The secondary aim of this article was to analyze the impact of exposure to room conditions and associated dehydration on the biomechanical properties of cadaver tissue. Therefore, each tendon was tested before and after 2 hr of exposure to room conditions. The resulting dehydration caused a significant increase of the Young's modulus for the thawed fresh‐frozen tendons. The properties of the Thiel embalmed tendons were not significantly altered. In conclusion, this research promoted the use of fresh‐frozen specimens for biomechanical testing. Effort should, however, be made to minimize dehydration of the tested specimens. Clin. Anat. 28:994–1001, 2015. © 2015 Wiley Periodicals, Inc.     

Thiel-fixation preserves the non-linear load-deformation characteristic of spinal motion segments, but increases their flexibility

Human cadaveric specimens are recommended as the best option for in-vitro tests. However, fresh human spine specimens are often difficult to obtain. Further problems are the potential risk of infection and they can only be used over a limited test period. Therefore, the use of embalmed specimens is often discussed. The most common method is formalin fixation. However, this type of embalming can result in failure, because the biomechanical properties of the tissue is partially influenced. In recent years the development of the new method, the fixation according to Thiel, could provide an alternative to fresh or formalin-fixed specimens. The aim of the present study is to compare the biomechanical properties between fresh and Thiel-fixed spine specimens, and to compare the data to previous data of a test with formalin fixation. For the study, six L1-L2 spinal segments from 16-week-old calves were biomechanically tested. The parameters, range of motion and neutral zone, were determined in flexion/extension, right/left lateral bending and left/right axial rotation. The results showed that the specimens kept their non-linear load-deformation-characteristic after Thiel fixation. The range of motion of Thiel-fixed specimens increased relative to the unembalmed state by approximately 22% in flexion-extension, 23% in lateral bending (p<0.05) and 45% in axial rotation (p<0.05). In conclusion, the results still suggest a preference for fresh cadaveric spine specimens for quantitative biomechanical in-vitro testing, because they provide the best physiological conditions. However, for preliminary tests, which may only be used for orientation, embalmed specimens using the Thiel fixation method might serve as an alternative. Compared to formalin-fixated specimens which become approximately 5 times stiffer and completely lose their non-linear load-deformation-characteristic, as found in a previous study; the Thiel fixation maintains the non-linear load-deformation-characteristic but increases the range of motion.     

Tissue biomechanics of the human head are altered by Thiel embalming,restricting its use for biomechanical validation

Thiel embalming is a well‐known method of anatomical fixation giving lifelike optical and haptic tissue properties. Beyond these characteristics, Thiel embalming may also be a promising method to provide lifelike tissues for validation purposes of human head biomechanics. Recent investigations using Thiel‐embalmed human tissues of the upper and lower limb yielded contradicting biomechanical results on fixation‐induced changes in the tissues' load‐deformation behavior. It is to date unclear if Thiel embalming may have a softening or stiffening effect on human soft tissues or no global effect on biomechanics compared to the fresh state, with the latter being the most desirable outcome. The given study aimed at assessing the effects of Thiel embalming on the uniaxial tensile properties of human head soft tissues. Age‐matched fresh and Thiel‐embalmed dura mater, temporalis muscle, temporalis muscle fascia, and scalp samples were examined. Dura, fascia, and scalp samples showed significantly different elastic moduli compared to fresh tissues (all P < 0.01). The observed ultimate tensile strength supports the theory of an increased collagen crosslinking of the embalmed tissues when compared to the fresh state. Thiel‐embalmed muscles failed any tensile testing approach as a result of the muscles dissolving due to the embalming. Furthermore, collagen integrity seems altered in scanning electron microscopy by the Thiel embalming, limiting their use for ultrastructural failure analyses. Thiel‐embalmed soft tissues may consequently not serve to reflect the biomechanical properties of the human head. Consequently, the application of Thiel embalming should be limited to preliminary tests for biomechanical purposes. Clin. Anat. 32:903–913, 2019. © 2019 Wiley Periodicals, Inc.     

Thiel-embalming technique: investigation of possible modification in embalming tissue as evaluation model for radiofrequency ablation

Contrary to freezing preservation and formalin embalming, Thiel embalmed cadaver presents soft texture and color very close to that of living organism, and many applications based on Thiel embalmed cadavers have been reported. However, Thiel embalmed cadavers cannot be used as reliable evaluation model for radiofrequency ablation (RFA) due to dramatic changes of electrical conductivity in the embalmed tissue. To address this issue, we investigated various modifications of the original Thiel embalming solution. By altering the chemicals' species and concentration we figured out a formula that can greatly reduce the embalming fluid's electrical conductivity without significantly compromising the 18-day embalmed kidney samples' suppleness and color. We also investigated a two-stage embalming technique by first submerging the kidney sample into original Thiel's tank fluid for 28 days, then the sample was withdrawn from the tank fluid and placed into modified dilution fluids for additional two weeks. Stiffening and discoloration occurred in these diluted samples implying the reversibility of Thiel-embalmed tissues' suppleness and color with the removal of the strong electrolytes. This study presents a modified embalming method which could be used for RFA evaluation and also helps our understanding of the mechanism of embalmment process.     

复杂胸椎骨折中CT图像三维重建的应用探讨

目的直观立体地显示复杂胸椎骨折的图像，探讨螺旋CT医学图像三维重建在复杂胸椎骨折诊断中的价值及其对手术的指导意义。方法对92例胸椎骨折患者采用螺旋CT进行薄层扫描和三维重建进行诊断。CT扫描全部采用Siemens SOMATOM Sensation16型多排高速螺旋CT机，1．0mm层厚。扫猫所得断层资料通过网络传送至计算机工作站进行处理，采用Window．NT3．51平台上Insisht三维重建软件进行三维重建。结果三维CT图像能够围绕X轴和Z轴任意旋转、切割以从不同角度观察，能够清晰显示复杂的胸椎骨折和狭窄椎管的解剖形态特点。结论三维CT重建在胸椎骨折方面具有很大的临床应用价值，有助于提高脊柱骨折手术的安全性和精确性并对患者预后的估计提供帮助。     

Thiel embalming: Quantifying histological changes in skeletal muscle and tendon and investigating the role of boric acid

Cadaver preservation methods impact their utilization in anatomical research and teaching. Thiel-embalmed cadavers show flexibility, however, the cause remains poorly understood. This study aimed to (1) describe qualitative and quantitative histological differences between Thiel-embalmed and formalin-fixed skeletal muscle and tendon tissue; (2) investigate whether boric acid in Thiel solution is solely responsible for modification of tissues; and (3) explore whether the modifications observed could potentially explain the mechanisms underpinning flexibility of Thiel cadavers. Skeletal muscle and tendon samples were harvested from mice preserved using formalin, Thiel solution, or modified-Thiel solution (without boric acid). Using standard H&E and Gomori's trichrome histological methods, tissues were examined to determine whether differences were apparent between the preservative treatments. Differences were present between the Thiel and formalin-fixed tissues; formalin-fixed samples remained substantially more intact while Thiel-embalmed samples showed fiber fragmentation and lack of nuclei. The mean cell diameter of Thiel-embalmed muscle (24.4 μm) was significantly smaller (P < 0.005) than formalin-fixed muscle (40.7 μm). There was significantly greater (P < 0.005) fragmentation in Thiel-embalmed muscle (631.5 per 1 mm²) compared to formalin-fixed muscle (75.4 per 1 mm²). Samples embalmed using modified-Thiel showed a severe lack of integrity within internal tissue structure. This suggests that Thiel solution significantly alters tissue structure at cellular level, with quantitative data demonstrating measurable differences between Thiel and formalin-fixed specimens. While the precise mechanism for these alterations remains unknown, it is shown that boric acid is not the only component of Thiel responsible for degradation of internal tissue structure. Clin. Anat., 33:696–704, 2020. © 2019 Wiley Periodicals, Inc.     

Clinically relevant landmarks of the frontotemporal branch of the facial nerve: A three‐dimensional study

The frontotemporal branch of the facial nerve (FTN) is vulnerable during craniofacial surgeries due to its superficial course and variable distribution. Surface landmarks that correlate with the underlying course of the FTN can assist in surgical planning. Estimates of the course of FTN commonly rely on Pitanguy's line (PL), which utilizes variable soft‐tissue landmarks. The purpose of this study was to evaluate palpable surface landmarks to predict the course and distribution of FTN using 3D modeling. Fifteen half‐heads were used. In five formalin‐embalmed specimens, surface topography was obtained using a FARO® scanner and landmarks corresponding to PL, porion, supraorbital notch, frontozygomatic and zygomaticotemporal sutures, and supraorbitomeatal line (SOML) and infraorbitomeatal line (IOML) were demarcated/digitized using a Microscribe? digitizer. A preauricular flap was raised, and branches of FTN were isolated and digitized. The data were reconstructed into 3D models (Geomagic®/Maya®) to quantify landmarks. In 10 Thiel‐embalmed specimens, four independent raters identified/palpated and pinned the frontozygomatic and zygomaticotemporal sutures and PL. Data were collected and analyzed using the same protocol as in the first part of the study. Landmarking of PL was inconsistent between raters and not representative of FTN distribution. The easily identifiable surface landmarks defined in this study, a line 12 mm anterior to the porion along the SOML and IOML and a line joining the zygomaticotemporal and frontozygomatic sutures, comprehensively captured the distribution of FTN. The raters found a mean of 21 ± 2 branches between the lines out of a total of 22 ± 2 branches. These landmarks may be used clinically to avoid injury to FTN. Clin. Anat. 25:858–865, 2012. © 2012 Wiley Periodicals, Inc.     

Elastic properties of Thiel‐embalmed human ankle tendon and ligament

Thiel embalming is recommended as an alternative to formalin‐based embalming because it preserves tissue elasticity, color, and flexibility in the long term, with low infection and toxicity risk. The degree to which Thiel embalming preserves elasticity has so far been assessed mainly by subjective scoring, with little quantitative verification. The aim of this study is to quantify the effect of Thiel embalming on the elastic properties of human ankle tendons and ligament. Biomechanical tensile tests were carried out on six Thiel‐embalmed samples each of the peroneus longus, peroneus brevis, and calcaneal tendons, and the calcaneofibular ligament, with strain rates of 0.25%s^?1, 2%s^?1, and 8%s^?1. The stress?strain relationship was calculated from the force‐extension response with cross‐sectional area and gauge length. Young's modulus was determined from the stress?strain curve. The results showed that the tendon and ligament elasticity were lower after Thiel embalming than the literature values for fresh nonembalmed tendons and ligament. The biomechanical tensile test showed that the measured elasticity of Thiel‐embalmed tendons and ligaments increased with the strain rate. The Thiel embalming method is useful for preserving human ankle tendons and ligaments for anatomy and surgery teaching and research, but users need to be aware of its softening effects. The method retains the mechanical strain rate effect on tendons and ligament. Clin. Anat. 28:917–924, 2015. © 2015 Wiley Periodicals, Inc.     

新型肝脏管道模型的数字化制造研究

目的　设计并制作内部管道与肝实质外形兼备的新型肝脏管道模型。  方法　选取一具新鲜的人体肝脏标本,肝静脉及门静脉灌注后行64排螺旋CT扫描,利用Mimics软件重建门静脉、肝静脉及肝实质三维模型。在Magic4.0软件中设计肝脏管道与肝实质外壳模具的装配结构。将设计好的模型通过快速成型机进行模型的三维打印,并进行组装形成管道铸模模具。将融化的透明果冻蜡注入铸模模具内,待蜡凝固后,除去肝实质壳模具,获得新型肝脏管道模型。  结果　本研究通过三维重建、快速成型及模具技术成功地制作了内部管道与肝实质外形兼备的新型肝脏管道模型。模型清晰地显示肝内管道的分布情况,位置关系,分支关系,管道直径等,快速成型管道的最小直径约为1.2 mm。由透明果冻蜡制作的肝实质外形良好,清晰透明,质地与肝实质相近。   结论　新型肝脏管道模型表现力丰富,容易保存。它拓展了铸型标本在医学教育,科研,临床上的应用。     

A new contrast agent for radiological and dissection studies of the arterial network of anatomic specimens

Purpose

The aim of the present study is to propose a new contrast agent that can be easily applied both to CT and dissection studies to replace lead oxide based formulas for comparative anatomical analyses of the vascularisation of cadaveric specimens.

Methods

The infusion material was an epoxy resin, especially modified by the addition of barium sulphate to enhance its radiopacity. The final copolymer was toxicologically safe. To test the properties of the new material, several cadaveric limb injections were performed. The injected specimens were both CT scanned to perform 3D vascular reconstructions and dissected by anatomical planes.

Results

There was a perfect correspondence between the image studies and the dissections: even the smallest arteries on CT scan can be identified on the specimen and vice versa. The properties of the epoxy allowed an easy dissection of the vessels.

Conclusions

The new imaging techniques available today, such as CT scan, can evaluate the vascular anatomy in high detail and 3D. This new contrast agent may help realising detailed vascular studies comparing CT scan results with anatomical dissections. Moreover, it may be useful for teaching surgical skills in the field of plastic surgery.     

A comparative study of vascular injection fluids in fresh‐frozen and embalmed human cadaver forearms

Over the years, various vascular injection products have been developed to facilitate anatomical dissections. This study aimed to compare the most commonly used vascular injection products in fresh‐frozen and formalin‐embalmed cadaver specimens. An overview of the properties, advantages and limitations of each substance was given, and a comparison of vascular infusion procedures in both preservation methods was made. A literature search was performed in order to identify the most commonly used vascular injection products. Acrylic paint, latex, gelatin, silicone, Araldite F and Batson's No. 17 were selected for the study. One fresh‐frozen and one embalmed cadaver forearm were infused with each injection product according to a uniform protocol. The curing time, skin‐ and subcutaneous tissue penetration, degree of filling of the arterial tree, extravasations, consistency of the injected vessels during dissection, and the costs of each injection fluid were noted. There was a large variation between the injection fluids in processing‐ and curing time, colour intensity, flexibility, fragility, elasticity, strength, toxicity and costs. All fluids were suitable for infusion. The penetration of injection fluid into the skin and subcutaneous tissue was significantly better in fresh‐frozen specimens (P = 0.002 and P = 0.009, respectively), with significantly smaller branches casted (P = 0.004). Vascular infusion of fresh‐frozen cadaver specimens results in a significantly better filled coloured arterial tree, enabling more detail to be achieved and smaller branches casted. The biomechanical properties of fresh‐frozen soft tissues are less affected compared with formalin fixation. All the injection fluids studied are suitable for vascular infusion, but their different properties ensure that certain products and procedures are more suitable for specific study purposes.     

胸导管结扎对大鼠脂质代谢和胰组织结构的影响

目的:探讨胸导管结扎对脂质代谢的影响,揭示淋巴回流障碍诱发胰组织的显微和超微结构变化.方法:SD大鼠随机分为假手术对照组和结扎胸导管模型组.术后6个月取静脉血标本进行血脂检测;部分胰组织标本,H-E和刚果红染色光镜观察;部分胰组织进行透射电镜观察.结果:(1)模型组大鼠游离脂肪酸和甘油三酯浓度明显下降,胆固醇浓度无显著变化.(2)光镜观察显示模型组大鼠的胰腺小叶间隙增宽,脂肪堆积和淋巴管扩张.(3)透射电镜观察显示模型组大鼠的胰岛细胞间隙增宽,细胞间隙及细胞内可见大量脂滴样物质、红细胞和胶原原纤维样结构.结论:胸导管结扎可引起胰腺结构变化和影响胰腺的内、外分泌功能.     

Three-dimensional CT angiography: a new technique for imaging microvascular anatomy

To date there has been no satisfactory research method for imaging microvascular anatomy in three dimensions (3D). In this article we present a new technique that allows both qualitative and quantitative examination of the microvasculature in 3D. In 10 fresh cadavers (7 females, 3 males, mean age 68 years), selected arteries supplying the abdominal wall and back were injected with a lead oxide/gelatin contrast mixture. From these regions, 30 specimens were dissected free and imaged with a 16-slice spiral computed tomographic (CT) scanner. Using three-dimensional CT (3D-CT) angiography, reconstructions of the microvasculature of each specimen were produced and examined for their qualitative content. Two calibration tools were constructed to determine (1) the accuracy of linear measurements made with CT software tools, and (2) the smallest caliber blood vessel that is reliably represented on 3D-CT reconstructions. Three-dimensional CT angiography produced versatile, high quality angiograms of the microvasculature. Correlation between measurements made with electronic calipers and CT software tools was very high (Lin's concordance coefficient, 0.99 (95% CI 0.99-0.99)). The finest caliber of vessel reliably represented on the 3D-CT reconstructions was 0.4 mm internal diameter. In summary, 3D-CT angiography is a simple, accurate, and reproducible method that imparts a much improved perception of anatomy when compared with existing research methods. Measurement tools provide accurate quantitative data to aid vessel mapping and preoperative planning. Further work will be needed to explore the full utility of 3D-CT angiography in a clinical setting.     

管道铸型技术与血管造影3D可视化相结合

目的:以肝为例,探索将管道铸型与血管造影及3D可视化技术进行整合,充分揭示同一器官内部各管道系统之间的相互关系。方法:分别从肝静脉灌注自凝牙托灌注填充剂,从肝门静脉灌注乳胶、羧甲基纤维素-氧化铅填充剂。运用多层螺旋CT进行层距0.5mm薄层扫描,获取二维数据,应用Mimics软件对肝内的管道系统进行3D可视化。结果:重建后的肝门静脉充盈饱满,层次清晰,边缘光滑,层次分明。排除干扰后,自凝牙托材料灌注的肝静脉同样可以在运用CT扫描后,获取理想的管道三维重建模型。图像融合后能清晰显示肝门静脉和肝静脉在肝内的相互位置关系。结论:采用管道铸型技术与血管造影3D可视化相结合技术,不仅能在同一器官同时显示各管道系统的相互关系,更能在同一器官分别显示各管道系统。     

IFN-β和angiostatin对猪淋巴管内皮细胞生成的影响

目的探讨IFN-β和angiostatin分别在离体和在体条件下对淋巴管内皮细胞生成的影响。方法淋巴管在体抑制实验观察活体被切断的淋巴管应用抑制因子后的再生情况,应用光镜、透射电镜、共聚焦显微镜观察离体猪胸导管内皮细胞的形态结构,应用MTT法来确定IFN-β对淋巴管内皮细胞生成的抑制作用,采用Hoechst法检测细胞凋亡。结果手术切断兔前或后肢淋巴管5d后,生理盐水侧的淋巴管已愈合,angiostatin侧仍有大量染料渗漏。培养的胸导管内皮细胞的突出结构特点是胞质内有较多吞饮小泡以及从细胞膜上发出许多长突起。MTT法显示IFN-β对离体淋巴管内皮细胞的增殖有明显的抑制作用,IFN-β可引起细胞凋亡。结论 Angiostatin对在体淋巴管的愈合有抑制作用,IFN-β对离体淋巴管内皮细胞的增殖有明显的抑制作用并促进细胞凋亡。     

Normal vascular and biliary hepatic anatomy: 3D demonstration by multidetector CT

Due to constant innovations in radiological and surgical techniques, more accurate results are expected in the diagnostic and therapeutic procedures related to hepatic pathology. The aim of this work was to demonstrate the normal hepatic vascular and biliary anatomy using cadaveric livers and CT scans of the affected livers. Furthermore, using the CT scans, the authors intended to illustrate the most common morphological variations of the vascular and biliary anatomy. Four human cadaveric livers were injected with colored silicone mixed with radiological contrast solution in the common bile duct, in the proper hepatic artery, in the portal vein and in the inferior vena cava near the ostia of the hepatic veins (only one of these structures was injected in each liver). After obtaining the CT scans, 3D rendered models were created, which demonstrated the normal hepatic anatomy of the vascular and biliary structures. The International Anatomical Nomenclature was used for their classification (based on Couinaud's work). The 3D rendered CT models were also modified to illustrate the most common normal variations of the hepatic anatomy (found in the literature).     

Brain ultrasound rehearsal before surgery: A pilot cadaver study

It has been shown that brain ultrasonography (US) is an efficient tool for improving three‐dimensional (3D) spatial orientation during neurosurgical interventions. However, it necessitates specific training as it is highly operator‐dependent. To date, neurosurgeons have relied solely on intraoperative practice to improve their mastery of brain US; this has obvious limitations. Herein, we consider whether a study of brain US on human cadavers could enable a training platform for neurosurgeons and residents to be developed. Standard two‐dimensional (2D) brain US was performed on two human cadavers (one fresh‐frozen and one Thiel‐prepared) through left frontoparietal, left frontal, right temporal, and left parietal craniotomies. US workflow and image quality were assessed in both preparations. It was possible to assess US in both cadaver preparations; however, the specimen prepared with Thiel‐fixation performed better, with superior image quality and specimen usability at room temperature. US images were obtainable through all surgical corridors with the main intracranial anatomical landmarks easily identifiable. US of cadaveric brains is feasible and delivers good quality results. This technique could allow neurosurgeons to develop the expertise required for a successful clinical application preoperatively. Clin. Anat. 30:1017–1023, 2017. © 2017 Wiley Periodicals, Inc.     

Visualization of microvasculature by x-ray in-line phase contrast imaging in rat spinal cord

Computed tomography combined with angiography has recently been developed to visualize three-dimensional (3D) vascular structure in experimental and clinical studies. However, there remain difficulties in using conventional x-ray angiography to detect small vessels with a diameter less than 200 μm. This study attempted to develop a novel method for visualizing the micro-angioarchitecture of rat spinal cord. Herein, synchrotron radiation-based x-ray in-line phase contrast computed tomography (IL-XPCT) was used to obtain 3D micro-vessel structure without angiography. The digital phase contrast images were compared with conventional histological sections. Our results clearly demonstrated that the resolution limit of the spatial blood supply network in the normal rat thoracic cord appeared to be as small as ~10 μm. The rendered images were consistent with that obtained from histomorphology sections. In summary, IL-XPCT is a potential tool to investigate the 3D neurovascular morphology of the rat spinal cord without the use of contrast agents, and it could help to evaluate the validity of the pro- or anti-angiogenesis therapeutic strategies on microvasculature repair or regeneration.     

Immunohistochemical differentiation between lymphangiographically verified lymphatic vessels and blood vessels

Summary In order to investigate the antigen profile in human lymphatic vessels when compared with blood vessels, postmortem retrograde lymphangiography was done via the thoracic duct on six patients. Formalin fixed, paraffin embedded tissue was stained immunohistochemically for Factor VIII-Related antigen (F VIII R:Ag), with Ulex Europaeus 1 lectin (UEA-1) and for laminin. The results show that the endothelium of blood vessels and lymphatics at all levels of the lymphatic system react positively following staining for Factor VIII-R:Ag and with UEA-1 lectin. The staining for F VIII R:Ag was generally weaker in the endothelial cells lining lymphatic vessels. Staining for the basement membrane component laminin can be used to distinguish lymphatic capillaries and smaller lymphatic collecting vessels from blood vessels.