Reduction in late postoperative pain after iliac crest bonegraft harvesting for cervical fusion: a controlled double-blinded study of 100 patients

Summary Background. A randomized prospective double-blinded study was conducted in 100 patients suffering from mono- or bisegmental cervical retrospondylosis or disc herniation.Method. In group I, 50 patients were treated by injection of 10ml Ropivacaine 7,5% at the iliac crest bonegraft donorsite. Local anaesthetic (LA) was injected through the wound drainage after closure of the muscle fascia, the suction drainage was opened after closure of the skin. Group II was treated with 0,9% saline. Operator and patient were blinded to the injected substance. Daily controls of pain intensity were made with the 10cm visual analog scale from 0 (no pain) to 10 (severe pain) for 5 days. All patients were questioned regarding pain character and movement provoking pain. Additional pain medication was standarized.Findings. Statistical analysis of mean pain intensity over the whole hospital stay showed a significant difference in pain intensity between the two groups (p=0,017, Chi-Square test). The comparison between pain intensity with LA and without LA showed a gradual increase in statistical significance from day 1 to day 5 (day 1: p=0,54, not significant; day 2: p=0,026; day 3: p=0,008; day 4: p=0,004; day 5: p=0,002).Interpretation. This data shows that intra-operative blockage of peripheral nociceptive structures results in decreased pain at later time points. We conclude that wound infiltration with 7,5% Ropivacaine after bonegraft removal at the iliac crest is effective in reducing postoperative pain.