The effect of multimodal balanced anaesthesia and long term gabapentin on neuropathic pain, nitric oxide and interleukin-1β following breast surgery

Objectives
To evaluate the effect of multimodal balanced anaesthesia and gabapentin (6 months) on neuropathic pain qualities, nitric oxide (NO) and interleukin 1-beta (IL-1β).
Methodology
This randomized study was conducted on 50 women scheduled for conservative breast surgery for cancer followed by chemotherapy and/or radiotherapy. Women enrolled into two groups; either to receive balanced general anaesthesia (GA) (control group) or ultrasound guided thoracic paravertebral with GA, multimodal balanced anaesthesia, (intervention group). Nociceptive pain was evaluated for 24 h. Neuropathic pain was evaluated using pain questionnaire 1 month postoperatively and neuropathic pain scale at 1, 3, 6 and 9 months. Gabapentin was prescribed to women reporting neuropathic pain 1 month postoperatively and for 6 months. NO and IL-1β were measured before operation, 1, 3, 6 & 9 months, postoperatively. Their relationship with neuropathic pain was assessed.
Results
Nociceptive pain was less in intervention group than control group immediately post operative, 4 h after surgery at rest and 8 h with movement. Neuropathic pain started few days postoperatively, in both groups. Its onset, sites, duration and precipitating factors did not differ between the groups. Sensitive, hot pain and unpleasantness reduced significantly 1 month postoperatively, in intervention group. Two months later, itchy, dull and sharp pain was significantly less in intervention group. At 6 months, most of neuropathic pain items except sharp and deep pain lowered significantly in intervention group. At 9 months, hot and superficial pain was still less in intervention group. NO decreased significantly 1 and 3 months postoperatively, while IL-1β was significantly lower through different times, in intervention group. IL-1β correlated well with neuropathic pain intensity and unpleasantness.
Conclusion
Breast surgery for cancer was associated with neuropathic pain that continued for 9 months after surgery. Multimodal balanced GA had positive impact on acute nociceptive and neuropathic pain. Gabapentin reduced almost all neuropathic pain qualities.