We present two cases of cancer patients with intractable mechanical and visceral pain that was unrelieved with either comprehensive medical management or intrathecal morphine who received intrathecal bupivacaine. While the continuous administration of a seemingly significant daily dose neither relieved pain nor caused measurable clinical changes, the addition of small, presumably negligible bolus doses on top of the continuous infusion resulted in spectacular pain control, clear thermoanalgesic suspended block, and in one of the patients, significant hypotension. To the best of our knowledge, such an observation has neither been reported before nor can we provide a satisfactory explanation for it. However, we believe it may have significant implications for the treatment of some patients, in particular, cancer patients with mechanical pain that cannot be adequately relieved with morphine whatever the route of administration.

Long-term intrathecal drug administration using implanted pumps is increasingly used in the treatment of chronic refractory pain [Anderson and Burchiel 1999, Neurosurgery 44 (1999) 289; Krames 2002, Best Pract Res Clin Anaesthesiol 16 (2002) 619; Wallace 2002, Neurology 59 (2002) S18]. Extensive clinical experience over the last 15 years suggests that in selected cases the technique is safe, although infections, system malfunction and drug-related complications have been reported. In most cases, drug-related spinal cord injuries have resulted from the compression of a spinal inflammatory mass or abcess rather than from a direct neurotoxic effect. We report on a case of toxic spinal cord lesion occurring after more than 3 years of uneventful continuous infusion of a mixture of bupivacaine and clonidine.

Intrathecal drug administration using implanted catheter and pump systems has been used in routine clinical practice for more than 20 years to treat chronic refractory pain or spasticity. Complications associated with the use of these systems include drug related adverse events as well as technical problems, most of which are related either to the catheter or the procedure. Although traumatic neural damage is exceedingly rare it is usually associated with significant neurological impairment. We present a case of asymptomatic intraspinal migration of an intrathecal catheter three years after an uneventful implantation. To the best of our knowledge, this complication has never been reported before.

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