Intrathecal Pain Pump Trial and Its Contraindications
Intrathecal Pain Pump Trial
Intrathecal pain pump surgery is performed either by pain specialist, neurosurgeon or orthopedic surgeon. Patient is carefully evaluated for intrathecal pain pump placement. Once patient is selected for placement of intrathecal pain pump then patient is carefully evaluated for psychological pain disorder. Following psychological evaluation by psychiatrist, patient will be considered for trial of intrathecal pain medication.
Selection Criteria for Intrathecal Pain Pump
Patients Are Selected For Intrathecal Pain Pump If One Or More Than One Of The Following Factors Are Observed-
- Chronic non-malignant pain not responding to oral opioids and all other option of treatment has failed or not available.
- Malignant cancer pain in terminally ill patient.
- Inadequate pain relief with high dosage of oral opioids
- Side effects like drowsiness, somnolence and sleep apnea with oral opioids.
- Opioid dependence
- Opioid addiction
Contraindications For Intrathecal Pain Pump
- Psychological Pain - Pain is subjective, a psychological pain will not respond to intrathecal opioids.
- Coagulopathy - Bleeding disorder may result in epidural hematoma or intrathecal bleeding which may cause pressure symptoms on spinal cord.
- Infection - Preexisting infection is contraindicated for surgery.
- Opioid Side Effects - Patient should not be considered for intrathecal opioid therapy if patient had side effects like nausea, vomiting, dizziness, and confusion with oral opioid medication.
Trial of Opioid Medication Delivered Through Intrathecal Pain Pump
Trial is performed by injecting opioid in epidural space or intrathecal space to evaluate side effects and efficacy of opioid as analgesic.
- Epidural Opioid Trial - Temporary epidural catheter is placed for trial dosage of opioids in lumbar epidural space. Distal end of catheter placed in epidural space is tunnel under skin and connected to external pump. Procedure is performed under local anesthetics in surgical center. Patient is discharged home with instruction. Epidural dosage of opioid is increased once or twice a day. Epidural opioid dosage necessary to achieve optimum pain relief of 50% is evaluated. Catheter may be left in epidural space for 7 to 10 days.
- Intrathecal Opioid Trial - Temporary intrathecal catheter is placed for trial dosage of opioids in lumbar intrathecal cerebrospinal fluid. Distal end of catheter is tunneled under skin and connected to external programmable pump. Procedure is performed under local anesthetics in surgical center. Intrathecal opioid dosage required to relieve pain is lot less than epidural opioids. Pain relief is titrated carefully with opioid dosage. Catheter is monitored for bleeding and infection daily.
- Patient Monitoring - Patient is discharged home with instruction. Pump used for delivery of epidural and spinal medications are different. Volume and dosage required to relieve pain in epidural trial is 6 to 10 times more than intrathecal trial of opioid medications. Pain coordinator (nurse) or physician should be accessible for patient and close relatives for 24 hours until catheter is removed and trial is completed. Pain coordinator will monitor function of device, side effects of medications and available for any trouble shooting with external pump. Nurse and/or physician will see patient daily for infection and follow up. Patient is closely monitored for 50% or more pain relief while receiving epidural or intrathecal opioid medication. Dosage of intrathecal opioids to achieve 50% or more pain is lot less than epidural dosage.
- Choice of Trial Medication - Pain medication used for trial is either morphine or Hydromorphone. Intrathecal trial dose of hydromorphone or morphine required to reduce pain by 50% or more in average patient is between 0.2 mg /d to 0.75 mg per day. Patient taking high dosage of oral opioids may need up to 2 mg/ 24 hours or more of intrathecal morphine or hydromorphone. Patient suffering with malignant pain for several months prior to trial and taking several hundred mg of opioids may need intrathecal dosage of hydromorphone or morphine close to 5 mg or more.
- Epidural Opioids Medications - Epidural dosage of opioid to achieve 50 % pain relief can be 2 per day to 20 mg per day depending on oral opioid dosage, severity of pain, opioid resistance or tolerance.
Selection Of Patient For Permanent Placement Of Intrathecal Pain Pump
Intrathecal opioid trial is conducted for 2 to 7 days. Trial over 7 days may result in infection since catheter is exposed to atmosphere. Pain relief of 50% or more is considered as adequate to consider patient for surgery to insert pump and catheter. Patient activities are monitored during trial period. Improvement in activities is one of the goals to be achieved following intrathecal opioid treatment. Patient is encouraged to be active during trial. Patient is selected for permanent placement of catheter and intrathecal pain pump after successful pain relief during trial period.