Intrathecal drug delivery systems are effective
tools in the treatment of chronic pain or spasticity.
Using intrathecal drug delivery systems, drugs
are directly infused into the cerebrospinal fluid
and gain access to critical receptors in the central
nervous system. This delivery method allows for
the use of markedly reduced doses of medications
to produce the same effects as seen with
higher orally administered doses. Reduced dosing
produces fewer side effects, creating a more
favorable treatment course for patients already
suffering from chronic pain or spasticity. Complications
with intrathecal drug delivery systems
can occur during both the implantation process
and the postoperative maintenance of the device.
The most common procedure carried out during
postoperative maintenance of these devices is the
intrathecal pump refill. This procedure must be
performed by experienced practitioners in a systematic
way in order to prevent complications. The
most dreaded of these complications is inadvertent
injection of medication into the subcutaneous
space as opposed to into the device, commonly
referred to as a “pocket fill.” This paper describes
and recommends the routine use of color flow doppler
ultrasonography as an easy, safe, and effective
tool to reduce the chance of a catastrophic “pocket
fill.” Routine utilization of live color flow ultrasound
guidance during pump refills allows the practitioner
to carefully document flow of medication into the
pump under the silicone septum. It also allows for
demonstration of no leakage from, or fluid increase
superficial to, the septum. Additionally, 2 ultrasound
images are obtained to document color flow deep
to the septum and no color flow/leak/fluid superficial
to the septum. Although this complication is
rare, it can lead to severe complications including
oversedation, respiratory depression, and death. As
such, we believe that the utilization of color phase
doppler ultrasonography could further reduce this
incidence.
Key words: Analgesics, opioids, chronic pain, drug
overdose, infusion pumps, implantable, injections,
spinal, medication errors, spasticity, ultrasonics,
methods, ultrasonography, interventional
Longevity and Cost of Implantable Intrathecal Drug Delivery Systems for Chronic Pain Management: A Retrospective Analysis of 365 Patients