Role of pretrial systemic opioid requirements, intrathecal trial dose, and non-psychological factors as predictors of outcome for intrathecal pump therapy: one clinician's experience with lumbar postlaminectomy pain.

OBJECTIVE: Non-psychological parameters may predict pump success.
METHODS: Review was performed on 35 implants for gender, age, pretrial/trial dose, baseline visual analog scale (VAS), and pain location. One-year outcomes were % change VAS/intrathecal dose and medication change. Spearman coefficients correlated pretrial/trial dose, age, baseline VAS, and % change in VAS/intrathecal dose. Wilcoxon Rank-Sum tests correlated gender/pain location and % change in VAS/intrathecal dose. Pretrial/trial dose, baseline VAS, and medication change was tested using Wilcoxon Rank-Sums. Chi-square was used to correlate medication change with gender/pain location. A two-sample t-test compared age and medication change.
RESULTS: Positive correlation between % change VAS and trial dose was noted. Greater age correlated with lower VAS and % dose change. Marginally significant difference in % dose change by pain location was present with higher doses for leg pain.
CONCLUSION: Trial dose, age, and partially pain location are good predictors of pain relief.