Baclofen Pumps

 

  • Introduction- Baclofen pumps are placed in children and adults for control of spasticity. Spasticity is a condition in which there is a cerebral or spinal cord injury resulting in increased muscle tone.  The increased tone can be incredibly painful and debilitating.
  • Treatment alternatives.
    • Oral baclofen- GABA agonist that crosses BBB
    • Dantrolene- inhibits release of sodium from SR
    • Benzos- diazepam
    • Clonidine
    • Dorsal rhizotomy- excellent in children with spastic diplegia
  • Test dose
    • Normally performed by rehab physicians to evaluate safety and efficacy of intrathecal baclofen in a particular patient
    • Depending on size of patient but a typical dose in a large child is 50mcg injected during a lumbar puncture
    • Intrathecal baclofen side-effects
      • Drowsiness
      • Dizziness
      • Constipation
      • Muscular hypotonia
      • Brainstem dysfunction (respiratory depression, hypotension, bradycardia, coma)
      • Seizures- up to 10% of patients that receive IT Baclofen with a supraspinal cause of spasticity will have seizures.
  • Procedure
    • Positioning- Left lateral decubitus
    • Prep and Drape- Entry site for the intrathecal catheter is below the level of the cord in the lumbar spine (just like an LP), Prep around the flank from the inferior costal margin to the midline, and above the inguinal crease.
    • Intrathecal catheter- placed using a Touhy needle (15 guage). Several sources recommend placing the catheter slightly off of midline toward the direction of the pump. Right of the Spinous process. This limits the chance of microfracture which is a common cause of baclofen pump malfunction and withdraw.
    • Thread the catheter to approximately the T9-L1 level
    • Pump pocket- Baclofen pumps are large. You will need a big pocket in the right lower quadrant.
    • Tunnel the connecting catheter and connect the pump to the intrathecal catheter
  • Post-op
    • AP and Lateral Lumbar and Thoracic plain films to evaluate the system and ascertain where the tip of the catheter is.
    • Home medications (including oral baclofen)
    • Consult Rehab for pump programming and management
  • Complications
    • Infection- 1%
    • Catheter kink and migration- 4%
    • CSF leak collection under incision- 3%
    • Constipation- 3%
    • Headache- 2.4%
  • Baclofen Overdose
    • Symptoms- Drowsiness, Respiratory depression, vomiting, weakness, seizures, unequal pupils, pruritis, coma
    • Management
      • ABC
      • Interrogate the pump
      • Withdraw 40cc of CSF if the overdose is acute and from a pump malfunction
    • Physostigmine IV 1-2mg over 5-10 minutes- reverses drowsiness and respiratory depression
  • Baclofen Withdraw
    • Symptoms- Pruritis without rash, diaphoresis, hyperthermia, hypotension, AMS, increased spasticity
    • Complications- Rhabdomyolysis, multiple organ failure (can mimic sepsis, autonomic dysreflexia, malignant hyperthermia, neuroleptic malignant syndrome
    • Management
      • ABC
      • Oral baclofen, IT Baclofen through a LP
      • IV Benzodiazepines
      • Pump revision
  • Baclofen and Seizures
    • Notice that both overdose and withdraw induce seizures
  • Drug Tolerance
    • Patients may require a drug holiday secondary to escalating dose requirement of IT Baclofen
    • IT Morphine and fentanyl (not FDA approved) has been utilized during these holidays.
Joseph MillerBaclofen Pumps

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