Centralization: its prognostic value in patients with referred symptoms and sciatica.

STUDY DESIGN Prospective, comparative cohort study. OBJECTIVE To investigate the prognostic significance of centralization in patients with subacute sciatica and referred symptoms. SUMMARY OF BACKGROUND DATA Previous studies have shown that centralization occurs commonly in the nonspecific low back population, and its occurrence is associated with a good prognosis. The phenomenon has never been evaluated in a population with sciatica and referred symptoms. METHODS The sample pool was 104 consecutive patients referred for investigation of possible disc herniation. Of these patients, 60 were recruited into the study and underwent a standardized mechanical evaluation using repeated end-range movements, while symptom response was monitored to expose 2 groups: centralization group (CG) and noncentralization group (NCG). All patients were treated in the same way and were followed for one year. If patients did not have improvement surgery was considered. Outcomes included back and leg pain, disability, Nottingham Health Profile, and surgical outcome. RESULTS There were 25 patients who were classified in the CG, 35 in the NCG, and other baseline characteristics were similar between groups. At 1, 2, and 3 months, the CG had significantly better outcomes than the NCG. At 2 months, the CG had more improvements in leg pain (P = 0.007), disability (P = <0.001), and Nottingham Health Profile (P = 0.001). After 1 year, disability was less in the CG (P = 0.029). In the CG, 3 patients underwent surgery, in the NCG, 16 (P = 0.01). The odds ratio for surgery in the NCG was 6.2. CONCLUSION Patients with sciatica and suspected disc herniation who have a centralization response to a mechanical evaluation will have significantly better outcomes. Patients who do not have centralization will be 6 times more likely to undergo surgery.