A prospective, randomized, double-blind study of the efficacy of postoperative continuous local anesthetic infusion at the iliac crest bone graft site after posterior spinal arthrodesis: a minimum of 4-year follow-up.

STUDY

DESIGN

Parallel design, prospective, double-blinded, randomized, controlled trial composed of 2 independent groups treated with a continuous infusion catheter (saline vs. Marcain) placed into the iliac crest bone graft site (ICBG).

OBJECTIVE

To determine the long-term effects of postoperative continuous local anesthetic agent infusion at the ICBG harvest site in reducing chronic pain, narcotic usage and improving long-term, postoperative function and satisfaction with the surgical procedure.

SUMMARY OF BACKGROUND DATA: Harvesting iliac crest bone has been shown to be a source of pain and morbidity. In our initial study, we reported that patients who received local anesthetic at the graft site noted a reduction in acute postoperative pain (VAS) and narcotic usage. METHODS.: Twenty-six patients underwent posterior iliac crest bone graft harvesting. Patients were randomly assigned to receive 96 mL (2 mL/h x 48 hours) of either 0.5% Marcain or normal saline delivered via a continuous infusion catheter placed at the ICBG harvest site. Postoperative pain scores, narcotic use/frequency, activity level, and length of stay (LOS) were recorded and reported previously. At a minimum of 4 years after surgery (mean, 4.7 years; range, 4.5-5.4 years), all patients completed a questionnaire documenting their current VAS pain score (iliac crest), frequency of pain (days per month), level of activity, chronic pain at the ICBG site, and overall satisfaction with the procedure.

RESULTS

Nine of 11 patients (82%) in the treatment group and 10 of 14 patients (71%) in the control group were available at final follow-up (1 death occurred in the control group unrelated to the study). The treatment group had a statistically significant decrease in the graft site pain VAS score (1.4 vs. 4.8) and increased satisfaction with the procedure at a minimum of 4 years postprocedure (P < 0.05). Additionally, no patient in the treatment group developed chronic iliac crest dysesthesias (0 of 9) versus 7 of 10 patients (70%) in the control group (P < 0.05).

CONCLUSION

Continuous infusion of 0.5% Marcain at the ICBG harvest site significantly reduced chronic dysesthesias. Overall satisfaction with the procedure, number of painful days per month, and VAS scores were significantly better in the treatment group at 4 years. No long-term complications were attributed to either the ICBG site or the catheter-infusion system. The use of continuous local anesthetic infusion at the iliac crest may help in alleviating graft-related pain beyond the perioperative phase.