The reasons for improved survival following minimally invasive surgery remain elusive. Circulating mediators link surgical trauma, vascular and tissue homeostasis. Acute phase reactants, leukocytes and leukocyte Reactive Oxygen Species (ROS) are affected differentially by minimally invasive video-assisted thoracic surgery (VATS). Also, immunoglobulins, complement, TNF receptor and P-selectin changes have been observed, but the influence of minimally invasive surgery on these opsonins is less well defined. In this prospective randomised trial, 41 patients were randomly assigned to minimally invasive or open thoracic surgery, and immunoglobulins and vascular endothelial damage biomarkers were analysed. Humoral mediators (blood IgG, IgM, IgA; complement fragments C3, C4, and complement haemolytic index of activation CH50; TNF receptors I, II and P-selectin) were analysed before and 2, 5 and 7 days after surgery. Post-surgical changes in individual patients were determined.
Substantial immunoglobulin decreases followed minimally invasive and open surgery. Decreased IgG, IgM and IgE were detected 2 days after surgery, and IgG and IgM after 7 days. These changes were greater than haemodilution, reaching greater significance in open surgery patients. Immunoglobulin decreases followed lymphocyte decreases. In contrast, increased complement and inflammatory endothelial cell signals (C3 and C4, soluble TNFR-II) were detected 7 days after surgery. In both groups, increased C3 and TNFR-II followed early acute phase reactants CRP, IL-6 and ROS. Acute phase reactants and CD4/CD8 lymphocytes were factors most attenuated in patients undergoing minimally invasive thoracic surgery (VATS). This study suggests local trauma mediators are better biomarkers than circulating opsonins in defining the response to minimally invasive surgery, and a systems approach, comparing individual metabolic responses, is effective in small patient groups.