• VAS pain.
  
• Primary analysis will be the comparison between ketorolac and placebo groups.
  

• Change in oral opioid dose.
  

This study is part of a pain center grant that focuses on how pain, especially chronic neuropathic pain, alters the response to traditional and non-traditional analgesics (pain medications).

To treat persons with chronic pain, doctors sometimes implant a permanent tube in the spinal space in the back to give pain medicines. This tube, also called a spinal pump, is used to administer pain medicine directly to the spinal space. The most commonly used medicine given through the spinal pump is morphine which works well for most people, but sometimes loses tolerance, and larger and larger doses are needed, causing many side effects.

The purpose of this study is to find out if another medicine, ketorolac, when given with morphine in the spinal space, can stop or reverse the need for larger and larger doses of morphine. In animals, ketorolac has been shown to slow the need for an increase in morphine dosage and to reduce the morphine dose, while giving good pain control.

This study will enroll 30 individuals with chronic pain below the chest, caused by nerve injury, who are receiving morphine through a spinal pump. After learning to estimate pain accurately using thermal heat testing, participants will be randomly assigned to one of two study groups. Group one will receive the active study medication, ketorolac, while group two receives an inactive control (placebo). All participants will receive morphine (administered through the spinal pump). Afterwards, participants will rate their levels of pain, and provide samples of their spinal fluid (taken from the spinal tube/pump) for study. The above procedure will be repeated over a 4-week period.

Duration of the study for participants is 4 weeks, and includes ten visits to the research center, each lasting less than one hour.