Comparison of single- and dual-rod techniques for posterior spinal instrumentation in the treatment of adolescent idiopathic scoliosis.

STUDY DESIGN: Two groups of patients undergoing posterior spinal instrumentation and arthrodesis for treatment of adolescent idiopathic scoliosis were reviewed retrospectively. OBJECTIVE: To compare intraoperative concerns (operative time and blood loss), complications, and outcome in patients undergoing single or double posterior rod instrumentation for treatment of adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: The current treatment of idiopathic scoliosis includes posterior spinal instrumentation and arthrodesis. The standard configuration is a rectangular construct of dual rods connected by cross-links. Use of a single rod with multiple fixation points has been proposed as an alternative method to decrease operative time and blood loss, and to avoid late deep infections. METHODS: In this study, 21 patients underwent posterior instrumentation using a standard dual-rod construct, and 25 patients underwent posterior instrumentation using a solitary rod with multiple fixation points. Patients were assessed after a minimum 2-year follow-up period. RESULTS: No significant differences were found in blood loss, operative time, or overall frequency of long-term complications. Although not statistically significant, the trend was toward implant prominence in the double-rod group and implant failure in the single-rod group. Implant failure occurred only in instrumentations extending into the lumbar spine. There was no statistical difference in curve progression. CONCLUSIONS: Single-rod instrumentation and dual-rod constructs offered similar curve correction, blood loss, and operative time. However, single-rod instrumentation may be more prone to implant failure when extended into the lumbar spine.

Effects of probucol on plasma lipids, lipoproteins and parameters of high density lipoprotein metabolism.

Eight patients with primary hypercholesterolemia were treated with probucol for 17 weeks. Plasma total cholesterol, low density lipoprotein (LDL)-cholesterol, and high density lipoprotein (HDL)-cholesterol decreased by 16.6, 15.0 and 25.7%, respectively, in response to probucol treatment. Plasma levels of apolipoprotein B and apolipoprotein A-I also decreased, while apolipoprotein A-II concentrations were unchanged. The decrease in HDL-cholesterol levels was associated with a reduction in HDL particle size. No changes in the plasma lecithin:cholesterol acyltransferase activity or mass occurred in response to probucol treatment. In contrast, a significant 25% increase in plasma cholesteryl ester and triglyceride transfer activity occurred following probucol treatment. There was a positive correlation (R = 0.94) between cholesterol ester and triglyceride transfer. We propose that the increase in lipid transfer activity may in part explain the changes in HDL concentration and size, as well as the previously reported effect probucol has on reducing atherosclerosis in animal models.

A 70-kDa apolipoprotein designated ApoJ is a marker for subclasses of human plasma high density lipoproteins.

A new apolipoprotein, termed apolipoprotein J (apoJ), was purified from human plasma by immunoaffinity chromatography. ApoJ is a glycoprotein consisting of disulfide-linked subunits of 34-36 and 36-39 kDa. Each subunit is glycosylated and has a pI range of 4.9-5.4. ApoJ exists in the plasma associated with high density lipoproteins (HDL) and specifically with subclasses of HDL which also contain apoAI and cholesteryl ester transfer protein activity. Immunoaffinity purified apoJ-HDL subclasses have apparent molecular masses of 80, 160, 240, 340, and 520 kDa, as determined by gradient gel electrophoresis. By negative staining electron microscopy, apoJ-HDL range in diameter from 5 to 16 nm. Fractionation of plasma by vertical gradient density centrifugation revealed apoJ-HDL in HDL2 (d 1.063-1.125 g/ml) with the majority overlapping HDL3 (d 1.125-1.21 g/ml) and very high density lipoprotein (d 1.21-1.25 g/ml). The bimodal density distribution of apoJ-HDL suggests that these subclasses have a unique metabolic relationship and may play a role in the transport of cholesterol from peripheral tissues to the liver.