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.

Functional evaluation of the TKA patient using the coordination and variability of rising.

A kinematic analysis of the knee function is important for the evaluation of total knee arthroplasties (TKA). We used the coordination and variability of rising from a chair as functional knee parameters. Twelve knee patients were measured prior to surgery (=pre-TKA group) and one year after surgery (=post-TKA group). A group of 15 healthy, age-matched subjects was selected as control group. The WOMAC questionnaire, frequently used by orthopaedic surgeons, was administered prior to the test. The test consisted of 10 times rising from a low chair and 10 times from a high chair. Knee and hip angles and angular velocities were measured with electrogoniometers. The relative phase (=MRP) between hip and knee was a measure for the coordination of rising and the standard deviation of the relative phase of the 10 trials (=SRP) was a measure for the variability. The coordination and variability of rising of the TKA patients were compared to the control group, and the relationship with the WOMAC questionnaire was calculated. The coordination of rising from a high chair and the variability of rising from both chair heights were significantly different for the pre-TKA group compared to the control group (p<0.05). The post-TKA group showed no significant differences with the control group, which indicates a functional recovery after TKA implantation. The functional parameters correlated adequately with the subjective WOMAC questionnaire. This study showed that our method is an objective measure of functionality and it will be worthwhile to use it as an additional evaluation tool.

Gait and calf muscle endurance in patients with chronic venous insufficiency.

OBJECTIVE: To gain insight in gait and calf muscle endurance in patients with severe chronic venous insufficiency. METHODS: Fifteen patients with severe chronic venous insufficiency (healed or active ulcers) and 19 healthy controls were selected for this study. Subjects had to perform eight trials at preferred walking speed and eight trials at instructed walking speed (1.25 m/s) during which the gait parameters were recorded. The calf muscle endurance was tested by use of the heel-rise test. RESULTS: Patients had a significantly lower preferred walking speed (1.25 m/s +/- 0.31) compared with healthy controls (1.44 m/s +/- 0.0.15) (p = 0.039). During preferred walking speed patients had a wider base of support (p = 0.003), a bigger step time (p = 0.005), and a bigger stride time (p = 0.004) compared with healthy controls. At instructed walking speed only base of support was different between the two groups (p = 0.016). Patients had a significantly (p = 0.003) smaller number of heel rises (14.6 +/- 7.34), indicating decreased calf muscle endurance compared with controls (23.5 +/- 6.54). CONCLUSION: This study indicates a disturbed gait and decreased calf muscle endurance in patients with severe chronic venous insufficiency. The results of this study point to a possible role for gait and strength training in the rehabilitation process of patients with severe chronic venous insufficiency.

Coordination and stability of one-legged hopping patterns in patients with anterior cruciate ligament reconstruction: preliminary results.

OBJECTIVES: To investigate whether the intralimb coordination of the lower extremity during one-legged hopping in patients with anterior cruciate ligament reconstruction is different and less stable compared to control subjects. DESIGN: Measures of coordination dynamics are applied to study the coordination and stability of movement patterns of the knee and ankle in patients and control subjects. BACKGROUND: Due to several factors, such as loss of proprioceptive function and muscle weakness, the intralimb coordination of the lower extremity might be altered. METHODS: Seven patients and 13 healthy control subjects were instructed to hop in place on one leg for 10 seconds at a comfortable frequency for each leg separately. RESULTS AND CONCLUSIONS: The one-legged hopping movement pattern of patients with anterior cruciate ligament reconstruction one-year post-operative is different and less stable compared to healthy subjects, and thus is still impaired. RELEVANCE: This paper shows that patients, one year after reconstruction of the anterior cruciate ligament, have a different coordination pattern of the lower limb compared to a matched control group. Intersegmental coordination and stability, features that are often observed by eye during a rehabilitation process, are objectified in this study.

Scapho-lunate dissociation and arthrodesis. An experimental study with lesions of the interosseous ligament and fusions with K-wires.

The carpal mechanism is studied during a sectioning of the ligament between the lunate and the scaphoid. A tear in this ligament is frequently observed in the clinic. After experimental lesions of this ligament, some authors say there is little effect while others report significant changes. We have conducted repetitions of these sectioning experiments using roentgen stereophotogrammetry to assess the kinematics of the carpal bones. We have found very little effect. We have also fused the scaphoid to the lunate to find out what happens to the carpal mechanism when the ligament between these bones is made stiffer. Fusion is carried out with K-wires and the effect upon the carpal mechanism is studied again. Our K-wiring of the scaphoid and lunate shows that the carpus starts to behave unpredictablely. The positions of the wires influence the outcome significantly. RELEVANCE--:The ligament between the scaphoid and the lunate has been assigned a main function in the carpal mechanism. It is still in debate, however, whether a lesion of this ligament by itself leads to the typical scapho-lunate dissociation pattern of the carpus. We have shown that a disruption of this ligament hardly influences the carpal mechanism. In time though, other ligaments may become overstretched so that finally the typical pattern may show up. K-wiring of the lunate and scaphoid to restore the connection between these bones results in a primarily unstable joint.

Mechanics of drinking in the mallard (Anas platyrhynchos, anatidae).

Water drinking in the mallard is accomplished by a fine-tuned set of movements of upper and lower jaw and of the tongue. During immersion of the tips of the bill, the oral cavity is formed into smaller volumes containing water and into connecting tubes. Two mechanisms serve the water transport: (1) lingual and jaw movements press water from the water-containing spaces into the tubes; (2) a quantitative simulation of the shape of the oral cavity during immersion shows that the two tubes are so narrow that capillary action also contributes to water transport. Thereafter, the tips of the bill are raised until they point upward. In this "tip-up" position, water flows into the esophagus because of gravity. We conclude that, in addition to normal tip-up drinking observed in almost all Passeriformes and Galliformes, a second type of tip-up drinking may be distinguished in Anseriformes. The integration of the drinking mechanism, keeping the water inside the mouth, and the straining mechanism, expelling the water along the beak rims, is effected by specific actions of the elaborate lingual apparatus.