P020: STEPWISE ANALYSIS OF BACLOFEN PUMP FUNCTION
Yuriy Ivanov; William Grubb, MD; Rutgers Robert Wood Johnson
Introduction: 51 year old male with a history of B cell lymphoma and thoracic spinal cord involvement requiring decompressive laminectomy resulting in bilateral lower extremity paralysis and spasticity with bowel and urinary incontinence. He underwent a successful intrathecal baclofen trial and subsequent permanent implant of a 40ml pump by Neurosurgery for his severe, incapacitating spasms. Patient was referred to us by Neurosurgical team for pump management. After getting the pump refilled for the first time patient started complaining of increasing muscle spasms, episodes of hypertension, tachycardia and abdominal pain. Patient though that he did not get the proper medication put in his pump. He was brought into the office to troubleshoot his baclofen pump.
Methods: A stepwise algorithm was followed to evaluate the intrathecal Baclofen pump for actual pump failure versus catheter issues versus subtherapeutic dosing (Delhaas et. al.).
Pump was interrogated to check for any alarms and check the appropriate medicine concentration, delivery volume and rate. Patient was concomitantly put on his oral Baclofen regiment to prevent any possibility of Baclofen withdrawal.
Pump rotor examination was done under live fluoroscopic guidance to confirm that the motor was running.
Intrathecal pump side port was accessed with fluoroscopic guidance to check for free flowing cerebrospinal fluid aspiration.
Fluoroscopically guided myelogram with Iohexol 240 contrast was done through the intrathecal side port.
Replace the Baclofen in the intrathecal pump with new Baclofen to rule out any possibility of compounding errors
Bridge bolus was given to prime the catheter after side port access and CSF aspiration.
Continuing oral Baclofen intake and titrating the pump to therapeutic dose, at 15-20% per week.
Results: Pump interrogation did not yield any errors or issues.
Side port access revealed free flowing CSF aspiration (see image).
Myelogram showed unilateral contrast flow but no blockage (see image).
Discussion: Patient developed Baclofen withdrawal-like symptoms after getting his intrathecal pump refilled. A stepwise algorithm was followed to evaluate the intrathecal Baclofen pump (Delhaas et. al.).
In our experience the alarm typically only goes off if the motor is completely shut down. However if the rate and speed are affected, the only way to diagnose pump issues would be with x-ray and residual volume aspirations. If the volume aspirated is significantly different from the computer estimate the motor might be getting slowed down with contaminant or precipitate.
A Myelogram performed through the intrathecal side port allows one to evaluate the integrity of the catheter and also check for any abnormalities of the intrathecal CSF flow.
A CT myelogram, thoracolumbar MRI and oncologic consultation were obtained to evaluate for any Lymphoma disease progression. Pump was deemed to be functioning properly and so the Baclofen medication continued to be titrated up to therapeutic dose.
This case report serves as a guide to asses an intrathecal delivery system that is not performing as anticipated.