Does location of the catheter tip within the intrathecal space or mode of delivery affect the efficacy of intrathecal therapy?
There is no definitive evidence supporting close proximity of the catheter tip to the spinal level corresponding to the patient’s painful area or one method of drug delivery over another. However, research studies and clinical experience indicate that intrathecal administration does not result in drug distribution throughout the neuraxis—rather drug concentrates in close proximity to where it exits the catheter, particularly with slow, continuous infusion. Factors that influence the intrathecal spread of drug include lipophilicity of the drug, rate and volume of delivery, mode of delivery (e.g., continuous vs. microbolus), patient anatomy, patient activity levels, and patient positioning. Consequently, attempts to place the catheter at the appropriate dermatome for each patient depending upon the location of pain should be made to maximize the efficacy of intrathecal therapy.