Prognosis of cerebral lipiodol embolism caused by transarterial chemoembolization.

OBJECTIVES: Transarterial chemoembolization (TACE) plays an essential role in the management of unresectable hepatocellular cell carcinoma and other hepatic neoplasms. Cerebral lipiodol embolism (CLE) is a rare complication of TACE and its prognostic factors have not been well studied. The aim of this paper was to elucidate the prognostic factors of CLE based on clinical data obtained from our patients and cases published since 2004. METHODS: We present two patients with CLE, analyze the clinical data, and review all CLE cases published since 2004. A poor outcome was defined as stupor, coma, quadriplegia, or death within 45 days. Patients who had other neurological conditions within 45 days were considered as having a good outcome. RESULTS: The rate of poor outcome was 25.7% (9/35). Compared with the patients with good outcome, those with poor outcome were older (mean age 68.3 ± 7.3 vs. 58.3 ± 10.6 years, p = 0.03), more often female (76.9% vs. male 33.3%, p = 0.02), and more likely chemoembolized via both the right hepatic and right inferior phrenic arteries (44.4 vs. 8.7%, p = 0.02). DISCUSSION: The prognosis of CLE was related to age, gender, and the arteries selected for injection.

Changes in nuclear composition following cyclic compression of the intervertebral disc in an in vivo rat-tail model.

While in vitro studies have shown that mechanical loading can result in changes in the composition of intervertebral disc matrix, the effects of cyclic loading in vivo have not been considered. The objective of this study was to assess the effect of static and cyclic compression of different frequencies on the nuclear composition of the intervertebral disc. Thirty-six Sprague-Dawley rats were randomly divided into a control group (no pin insertion, no loading), a sham group (pins inserted in sixth and seventh caudal vertebrae, no loading), a static loading group (compression applied via pins) and cyclic loading groups (loading at 0.5, 1.5 or 2.5 Hz). Loading was applied for 1 h each day from the third to 17th day following pin insertion, and the caudal 5-6, 6-7 and 7-8 discs harvested to quantify proteoglycan content, collagen content and chondrocyte density in the nucleus pulposus. Static compression resulted in a significant reduction in total proteoglycan content as compared with the adjacent control disc, but this effect was not seen in any of the cyclic loading groups. However, comparison with the sham group appears to indicate an overall decrease in total proteoglycan content at the targeted and adjacent levels following cyclic loading. The 0.5 Hz loading group showed a significantly greater total proteoglycan content than all other compression groups, and also showed a lower total collagen content than the sham group. Results suggest that frequency dependent changes in composition occur in response to cyclic loading, but are not limited to the directly loaded disc alone. Further studies are required to verify this, but the choice of control appears to need careful consideration in all studies of this nature.

The effect of cyclic compression on the mechanical properties of the inter-vertebral disc: an in vivo study in a rat tail model.

OBJECTIVE: To assess the changes in the mechanical properties of inter-vertebral discs in vivo following static and cyclic compressive loading of different frequencies. DESIGN: An in vivo biomechanical study using a rat-tail model of the inter-vertebral disc.Background. Mechanical loading has been suggested as playing a major role in the etiology of disc degeneration, but the relationship is still not fully understood. METHODS: Sixty Sprague-Dawley rats were subject to daily compressive stress via pins inserted in the 6th and 7th caudal vertebrae over a two-week loading period. Animals were randomly divided into a sham group (pin insertion, no loading), a static loading group, or cyclic loading groups of 0.5, 1.5, or 2.5 Hz. Loading was applied for 1 h each day from the 3rd to 17th day following pin insertion, and the angular compliance, angular laxity, and inter-pin distance were measured in vivo at days 0, 3, 10 and 17. RESULTS: Changes in the inter-vertebral disc height depended on the frequency of loading, with the decrease in disc height in the static compression group significantly greater than that in all other groups, whereas the decrease in the 1.5 Hz cyclic compression group was significantly smaller than that in all other compression groups. CONCLUSIONS: Changes in disc properties depend on both the total load exposure and the frequency of loading. Cyclic loading in general produced less marked changes than static loading, but loading at particular frequencies may result in more severe changes. RELEVANCE: Previous studies have shown the in vivo changes in the mechanical properties of inter-vertebral discs to depend on the magnitude and duration of loading. In this study, a frequency dependent response to cyclic loading is also demonstrated.