Posterior lumbar spinal surgical pain leads to a severe degree of pain, and, hence, various means of pain management are required. Opioid pain medications such as morphine and fentanyl are frequently used as intravenously administered medications. To reduce the use of opioids for pain relief, a non-opioid form of pain relief, such as a Non-Steroidal Anti-Inflammatory Drug (NSAID), is often added to the regimen.

With the use of NSAIDs, however, the risk of systemic side effects such as bleeding, gastroduodenal bleeding, and kidney damage are being reported, and there is also a report of inhibition of spinal fusion; these risks limit the use of NSAIDs.

Nefopam, a new centrally-acting analgesic agent, has been reported in an animal study to desensitize post-surgical pain, and when used with an opioid analgesic, it indirectly controlled the NMDA receptor, which inhibited the generation of c-fos gene at the spine. There are also reports that Nefopam managed pain by inhibiting the serotonin reuptake receptors.

In clinical practice, the administration of Nefopam in patients who required post-surgical pain management reduced the use of opioid analgesics by 20-50 % and also reduced the prevalence of nausea and vomiting.

Therefore, the investigators considered whether the addition of Nefopam for intravenous patient-controlled analgesia in patients with lumbar spinal surgery would reduce the side effects seen in monotherapy with opioid analgesia and result in effective pain management. This study was conducted to address this question.

A. Inclusion criteria: The study subjects were adult patients, 20-65 years old, who were going to have spinal fusion surgery due to conditions such as spinal stenosis or disks and who fell under the American Society of Anesthesiologist physical status classifications of 1 or 2.

B. Exclusion criteria: Patients who could not read or understand the consent documents or who had a defect in blood coagulation, hepatectomy, pneumonectomy, nephrectomy, cardiovascular disease, administration of MAO inhibitor, ischuria, glaucoma, or a history of seizure were excluded from the study.