A Prospective, Randomized, Double Blind Study Evaluating the Efficacy of Post-operative Continuous Local Anesthetic Infusion at the Iliac Crest Bone Graft Site after Spinal Arthrodesis

Purpose: Harvesting iliac crest bone has been shown to be a source of pain and morbidity. Long-term patient complaints may be more closely associated with the procurement of the iliac crest bone graft (ICBG) rather than the primary surgical site. The purpose of this study was to determine the effects of post-operative continuous local anesthetic agent infusion at the ICBG harvest site in reducing pain, narcotic demand and usage, and improving early post-operative function after spinal fusion.

Methods: The study was a parallel designed, prospective, double-blinded, randomized, controlled trial of 37 patients who were enrolled after informed consent and IRB approval was obtained. During spinal arthrodesis surgery, patients were randomly assigned to receive 96-ml (2-ml/hr x 48 hours) of either normal saline (control group, n=22) or 0.5% Marcaine (treatment group, n=15) delivered via a continuous infusion catheter placed at the ICBG harvest site. All patients received Dilaudid PCA post-operatively. Pain scores, narcotic use/frequency, activity level, and length of stay (LOS) were evaluated. Physicians, patients, nursing staff, and statisticians were blinded to the treatment.

Results: Mean patient age was 60 years and similar between groups. Narcotic dosage, demand frequency, and mean VAS pain score was significantly less in the treatment (Marcaine) group at 24 and 48 hours (p<0 .05). The average LOS was 4.1 days with no statistically significant difference between the Marcaine or control groups. No complications were attributed to infusion-catheter system.

Conclusions: Continuous infusion of 0.5% Marcaine at the ICBG harvest site reduced postoperative parenteral narcotic usage by 50% and decreased overall pain scores. No complications were attributed to the infusion-catheter system. The use of continuous local anesthetic infusion at the iliac crest may help in alleviating acute graft-related pain, hastening patient recovery and improving short-term satisfaction.