How to drill the talar tunnel in ATFL reconstruction?

PURPOSE: Reconstruction of the anterior talofibular ligament may be indicated in cases of residual instability after conservative treatment. Often, a bone tunnel is used for fixation in the talar bone. The purpose of this study is to evaluate possible routes for drilling the talar tunnel. METHODS: Virtual tunnels were generated in a 3D bone model, oriented towards the following external landmarks: the talar neck, the most anterior point of the medial malleolus (MM), the most distal point of the MM, the most medial point of the MM, and the most posterior point of the MM. The parameters analysed for tunnels with lengths of 20, 25, and 30 mm were the maximum distance inside the bone and the distance from the tunnel to the bone surface. A minimal safe distance (MSD) was calculated for a tunnel with a diameter of 5 mm. RESULTS: The shortest measured distance before arriving outside the talar bone was 16.7 mm. The longest distances were obtained in the tunnels oriented towards the talar neck (mean value of 36.6, SD 2.8) and towards the most posterior point of the MM (mean value of 35.8, SD 0.3). Only one tunnel, measuring 20 mm in depth and oriented towards the most posterior point of the MM, revealed no individual values below the MSD. CONCLUSION: External landmarks are useful for drilling a talar tunnel during reconstruction of the anterior talofibular ligament. Only one tunnel, oriented towards the most posterior point of the MM, measuring 5 mm in diameter and with a maximum depth of 20 mm, was safe in all individuals. Surgeons should be aware of these limits when treating patients with ankle instability.

SIRT of liver metastases: physiological and pathophysiological considerations.

Available literature on the differences in circulation and microcirculation of normal liver and liver metastases as well as in rheology of the different radiolabelled microspheres [(99m)Tc-labelled macroaggregates of albumin (MAA), (90)Y-TheraSpheres and (90)Y-SIR-spheres] used in selective internal radiation therapy (SIRT) are reviewed and implications thereof on the practice of SIRT discussed. As a result of axial accumulation and skimming, large microspheres are preferentially deposited in regions of high flow, whereas smaller microspheres are preferentially diverted to regions of low flow. As flow to normal liver tissue is considerably variable between segments and also within one segment, microspheres will be delivered heterogeneously within the microvasculature of normal liver tissue. This non-uniformity in microsphere distribution in normal liver tissue has a significant "liver-sparing" effect on the dose distribution of (90)Y-labelled microspheres. Arterial flow to liver metastases is most pronounced in the hypervascular rim of metastases, followed by the smaller metastases and finally by the central hypoperfused region of the larger metastases. Because of the wide variability in size of labelled MAAs and because of the skimming effect, existing differences in flow between metastatic lesions of variable size are likely exaggerated on (99m)Tc-MAA scintigraphy when compared to (90)Y-TheraSpheres and (90)Y-SIR-spheres (smaller variability in size and probably also in specific activity). Ideally, labelled MAAs would contain a size range similar to that of (90)Y-SIR-spheres or (90)Y-TheraSpheres. Furthermore, the optimal number of MAA particles to inject for the pretreatment planning scintigraphy warrants further exploration as it was shown that concentrated suspensions of microspheres produce more optimal tumour to normal liver distribution ratios. Finally, available data suggest that the flow-based heterogeneous distribution of microspheres to metastatic lesions of variable size might be optimized, that is rendered more homogeneous, through the combined use of angiotensin II and degradable starch microspheres.

Cytomegalovirus-associated superior mesenteric vein thrombosis treated with systemic and in-situ thrombolysis.

A 56-year-old patient, first diagnosed with an acute cytomegalovirus infection, presented with progressive abdominal pain because of a superior mesenteric vein thrombosis for which he was treated with systemic thrombolysis and heparin in continuous infusion. As this therapy did not have the intended success after 5 days, an interventional radiological procedure was performed with local thrombolysis in the superior mesenteric artery resulting in recanalisation of the vein. Oral anticoagulation was initiated and continued for a period of 6 months. Mesenteric venous thrombosis is a relatively uncommon cause of mesenteric ischemia that can be associated with severe morbidity and significant mortality. With noninvasive techniques, it is possible to establish a diagnosis in the majority of the cases. The importance of an early diagnosis and therapy - not only with anticoagulation, but also thrombolysis in selected cases - is shown with this case and review of the literature.