|Sciatica: Studies of symptoms, genetic factors, and treatment with periradicular infiltration|
The findings of this thesis indicate that MRI is unable to distinguish sciatic patients in terms of the severity of their symptoms. Symptoms and signs of sciatica should receive the major emphasis when assessing the severity of the disorder and in subsequent clinical decision making.
In this sciatic patient population it was impossible to differentiate the genotypes (Trp2 and Trp3 alleles) on the basis of symptoms or clinical signs, whereas MRI has greater potential in this respect. A radial tear in a nonherniated disc may indicate the presence of the Trp2 allele, and the findings of TLS may indicate the presence of the Trp3 allele. The Trp2 allele is a rare gene defect, but the Trp3 allele is more common. In fact, in this study almost every fourth patient with sciatica had the Trp3 allele. These associations are important for physicians treating back pain patients with or without sciatica, as MRI findings may provide some estimates of the phenotype, and thus about the heredity of the lumbar disc disease to the offspring of the patients.
The present double-blind, controlled trial indicated that periradicular infiltration with a combination of methylprednisolone and bupivacaine offers only short-term clinical and economic benefit for sciatica compared to saline. On the basis of the subgroup analysis, however, steroid is clearly superior to saline in the case of contained herniations at the symptomatic level, in terms of both leg pain and medical costs, and possibly also in the need for operative treatment. In addition, if the lesion is located at the L3–4 or L4–5 level, steroid treatment is more likely to achieve good results in terms of disease-specific outcomes, but not in medical costs. In the case of extrusions steroid seems to be counter-effective. However, subgroup analyses carry a high risk of bias and the promising results in our subgroup analyses call for a verification study, which might be achievable using oral steroid medication. Consistent findings would provide us with an easily available, cost-effective, non-operative treatment for a large subgroup of sciatic patients.