Anesth Analg 2007;104:209-210
© 2007 International Anesthesia Research Society
doi: 10.1213/01.ane.0000247879.09095.a4
LETTER TO THE EDITOR
Editor-in-Chief Steven L. Shafer
Intrathecal Catheter Granuloma with Baclofen Infusion
Michael J. Cousins, MD, DSc, FANZCA, FRCA, FFPMANZCA, FAChPM (RACP), and
Paul M. Murphy, MB, MRCPI, FCARCSI, FFPMANZCA
Pain Management Research Institute, Royal North Shore Hospital and, University of Sydney, Sydney, Australia, mcousins{at}nsccahs.health.nsw.gov.au
In Response:
Drs. Narouze and Mekhail raise several questions (1) concerning our case report (2).
- We agree that "catheter tip-associated mass" would be better than the use of the term "occluded" because aspiration and injection were possible. One would expect no difference in volume of measured "residual" drug in the pump versus calculated volume, unless the catheter tip area was completely occluded, and this was not the case. We used an Indura intrathecal catheter whose multiple side holes extend 5–15 mm proximal to the catheter tip. A significant mass could be associated with the catheter tip area without occluding all of the side holes. Nevertheless, such a mass could absorb a significant amount of drug, decreasing the therapeutic response. Presumably if we had not removed this catheter, the mass would have grown to occlude all side holes.
- There was no documentation of increased pressure required on injection or aspiration during the myelogram.
- When we diagnosed the catheter-related mass, only one prior catheter had been inserted, and the involved catheter had been in place for 38 mo. Thus "trauma of repeated catheter implantation" is unlikely to be an explanation for the granuloma, although it is a possibility.
- The baclofen dose of 500 µg/day is in the middle range. We used Novartis (Lioresal) 2000 µg/mL solution. The final concentration was kept constant, and the dose was increased by increasing the rate of infusion. Three years of treatment is not modest. Yaksh et al. (3) reported a mean duration of therapy of 29 mo for granuloma formation.
The appearance of the intrathecal mass in this case is somewhat different from those reported in association with opioids. Because there was no evidence of inflammation at the more proximal sites of the intrathecal catheter, it seemed likely to us that the catheter tip-associated mass was caused by the baclofen.
REFERENCES
- Narouze, SN, Mekhail NA. Intrathecal catheter granuloma with baclofen infusion. Anesth Analg 2007;104:209.[Free Full Text]
- Murphy PM, Skouvaklis DE, Amadeo R, et al. Intrathecal catheter granuloma associated with isolated baclofen infusion. Anesth Analg 2006;102:848–52.[Abstract/Free Full Text]
- Yaksh TL, Hassenbusch S, Burchiel K, et al. Inflammatory masses associated with intrathecal drug infusion: a review of preclinical evidence and human data. Pain Med 2002;3:300–12.[ISI][Medline]
