Ultrasound-assisted Refill of Continuous Intrathecal Drug Delivery System as part of Management of Spasticity in the Community

Problem

Management of spasticity with via Baclofen Continuous Intrathecal Drug Delivery (CIDD) is a well-established technique (Saulino 2013, Godeld 2011). One component of this therapy is a regular scheduled refill of the system’s Baclofen (Bacthecal Medicianz Healthcare Pty Limited) reservoir. During this refill procedure, it is paramount to have an accurate placement of the needle into the drug reservoir to aspirate residual contents of the reservoir and refill of new Baclofen within the reservoir. We propose several advantages of an ultrasound guided refill procedure over conventional use of a template for this refilling process. Firstly, it would be possible to exclude any subcutaneous collections overlying the device therefore avoiding the potential to seeding unwanted fluid or material in the pump. Secondly, this provides the operator a visual appreciation of the port access and accurate marking of this site. In addition to these, the ultrasound image allows for the altered external shape to the device as a result of a mobile pocket therefore improving the trajectory of the refilling needle. This day-therapy technique has been adopted for patients with varied long-term neurological conditions such as Stiff Person Syndrome, Spastic Cerebral Palsy and Spinal Cord Injury.

Approach

With the patient lying supine, the pump residual volume along with device details is established with the use of a pump interrogator (Medtronic SynchroMed II, Minneaopolis, MN).Ultrasonography is performed by a suitably experienced operator (SG, MO-B) using a portable ultrasound machine (GE Healthcare Venue 40 Ultrasound). The injection port site is identified as a hypoechoic rectangle structure and image centred. This step is followed by gentle external skin markings with the use of a sterile surgical marker. A sterile field centred on the port site is prepared with aqueous chlorhexidine and draped with a pre-cut out sterile paper cloth. Sterile gloves and strict aseptic technique is maintained throughout the procedure. A standard non-coring Huber 22-guage needle (Refill Kit, Medtronic, Minneapolis, MN) is used. Utilising the external skin markings, the needle is placed perpendicular to the plane of the pump and gentle pressure applied until a ‘give’ is felt. At this stage, the accurate needle placement within the pump reservoir is further checked by drawing back on the syringe and cross-checking volumes aspirated against device data obtained at the start with the pump interrogator.

Findings

Since the adoption of these technique for CIDD Baclofen refilling at this establishment, there has been no complications and deemed to be the standard operating protocol for this procedure and has proven to be reliable.

Consequences

With the adoption of these techniques for CIDD Baclofen refilling, a more accurate and safer procedure can be carried out within an outpatient setting. This potentially reduces the rates of complications associated with inaccurate needle placement and failed filling procedure.