Managing Pain After Lumbar Spinal Fusion
Surgeons do everything they can to help reduce postoperative pain for patients having spinal surgery. With good pain control, patients can get up and move around sooner. This helps prevent complications and reduces the number of days in the hospital, not to mention the costs.
In this study, anesthesiologists compare different dosages (amounts) of a drug called pregabalin for postoperative pain control after lumbar spine fusion. This drug is already in use but the optimal dosage for this purpose is unknown.
Three groups of patients were formed. All patients in the study were male with a one- or two-level lumbar spine fusion. Anyone with a serious health problem was eliminated from the study. Likewise, anyone with an alcohol or other drug history was also excluded from participating.
Patients were assigned to one of the three groups randomly. One group received 75 mg of pregabalin one hour before surgery and again 12 hours after surgery.
The second group was given twice that amount of drug (150 mg) at the same time periods. The third group was the placebo (control) group. They were given fake pills. No one taking the pills knew which group they were in.
Normally, patients are given narcotics (opioids) to manage pain after lumbar
spine fusion surgery. But these medications have some very unpleasant side effects (nausea, vomiting, difficulty breathing).
Pregabalin has been selected as a possible adjunct (helper) treatment because the drug is quickly absorbed and acts in a predictable and safe manner. It works because it blocks the release of neurotransmitters (chemical messengers) that tend to overexcite the nervous system, ramping up pain messages.
The results of this experiment were measured in terms of pain intensity,
amount of opioid medication used after surgery, and frequency of rescue
analgesics required in the first 48 hours after surgery. Rescue analgesics
refer to additional pain relievers needed to get control of pain because pain intensity has increased too much and the patient is very uncomfortable.
For any anesthesiologists or other health care professionals involved in
administering anesthesia to spinal fusion patients, the authors describe the procedures they used in this study. Type and amount of anesthesia are provided along with method of drug administration, monitoring during the procedure, and end-of-surgery procedures.
Patients were observed carefully during the postoperative period for any adverse effects such as nausea, headache, inability to wake up (sedation), blurred vision, dizziness, and pain intensity. Patients were also asked to rate their level of satisfaction with the anesthesia and treatment for pain.
After collecting and analyzing all the data, they found that the higher dose of pregabalin (150 mg) was much more effective in controlling postoperative
pain. The group receiving the higher dose used much less narcotic for pain
control in the 48 hours after surgery. Symptoms after surgery were similar in
all three groups, so clearly the pregabalin at any dose did not compromise the patients in any way.
The need for additional rescue medications was also reduced in the 150 mg group. With less pain after surgery, there is an added benefit: reduced risk of becoming a chronic pain patient.
The authors conclude that although 150 mg of pregabalin before and after lumbar fusion surgery reduced postoperative pain, they still don't know if this is the optimal dose. Likewise, there's room for further study of the timing of the drug administration. This study only reviewed lumbar spine fusion, so other studies looking at other surgeries may yield different results.
For now we know that 150 mg of pregabalin is more effective in pain control than 75 mg (or placebo). The 75 mg dosage was about as helpful as the placebo, so it may be possible to reduce the amount of pregabalin given but not down to 75 mg.
The optimal dose may be somewhere between 75 and 150 mg -- or it could be at a level greater than the 150 mg tested in this study. Future studies with different doses while monitoring side effects are still needed. And repeating the same study with an all female group of patients is necessary before recommendations can be given for all adults.
Jong Chan Kim, MD, et al. Effective Dose of Peri-Operative Oral Pregabalin as an Adjunct to Multimodal Analgesic Regimen in Lumbar Spinal Fusion Surgery. In Spine. March 15, 2011. Vol. 36. No. 6. Pp. 428-433.