Optimizing pain control through the use of implantable pumps

Abstract

Intrathecal therapy represents an effective and well established treatment of nonmalignant as well as malignant pain. Devices available include mechanical constant flow pumps as well as electronic variable flow pumps with patient-controlled bolus release. The latter provide faster dose finding, individual pain control, and good acceptance by patients. New technologies such as membrane pumps and rechargeable devices are expected to be developed to clinical perfection. The available drugs for intrathecal therapy are listed according to the polyanalgesic consensus on intrathecal therapy. The integration of remote patient-controlled analgesia into electronic implantable devices, and the peptide analgesic ziconotide, have significantly improved intrathecal therapy. Complications include infections, catheter ruptures or disconnections, catheter granulomas, and technical dysfunctions. Further possibilities for optimizing intrathecal therapy include development of new drugs, drug side effects, catheter and pump technologies, and surgical techniques.

Keywords: implantable pumps; intrathecal catheters; intrathecal drugs; intrathecal pain control; intrathecal therapy; morphine pumps.

Figure 1

X-ray control of a suspected catheter rupture. The disconnected catheter endings are clearly visible showing also the metal connector situated in the proximal ending of the catheter.

Figure 2

Subcutaneous tissue necrosis at the caudal edge of an implanted SynchroMed II pump. Skin sutures after an attempt to correct the pump placement by moving the device more medially are still visible.

Figure 3

The SynchroMed II pump is now placed in the sheath of the rectus abdominis muscle and fixed to the fascia by non-resorptive sutures. This technique is possible only if the fatty tissue between the skin and electronic device does not exceed 25 mm in order to provide undisturbed telemetry.