On lumbar disc herniation : aspects of outcome after surgical treatment

Abstract

Knowledge about sciatica has grown immensely since the days of Hippocrates. Even so one must be impressed with the anatomical insights of those ancient times. Today we are able to describe at a molecular level how the intervertebral disc degenerates and how a herniation is evolved and its physical consequences for the patient. It is now possible, at least partially, to follow the impact a herniation creates on the compressed nerve root, the course of the pain impulses through all modifying systems, up to the brain – and yet not understand the reaction it may cause in that patient! There are still many, many knowledge gaps that need to be filled!

Study I: Outcome after surgery for children and adolescents was studied in the Swedish national spine register, Swespine, compared to adults 19-39 and older than 40 years. Children and adolescents were more satisfied with the surgical treatment than adult groups and there was a slight deterioration of outcome by age. Study II: Patients admitted to hospital and surgery non-electively, via the emergency ward, were compared to electively operated patients. At baseline the non-elective group, reported more pain, dysfunction and poorer quality of life, but after surgery all outcome values were almost equal, adjusted or not. Study III: Inflammation around the nerve root is an important factor in the pain elicited by disc herniation. The level of inflammation measured in serum with C-reactive protein before surgery was however not associated with outcome in a prospective study of 177 patients. On the other hand, ‘Plasminogen Activator Inhibitor 1’ (PAI-1), an important factor in fibrinolysis and scar modulation, was to some extent associated to poor outcome in the same cohort of patients. The exact reason for this association is not clear. It may be hypothesized that hypofibrinolysis is associated with excessive scar formation. Study IV: This thesis has used data from Swespine. The validity of these data may be questioned, as a fairly large proportion of patients are lost to follow-up. In an attempt to define if the loss to follow-up has an impact on the interpretation of data from Swespine, a comparison was made with a single-center study with very few patients lost to follow-up. There were some minor baseline differences between the groups, but outcome at 1 and 2 years, was almost equal in all used variables. These data indicate that non-responders in Swespine may be considered lost at random and would not influence the interpretation of data from Swespine.