Abstract ID: A11

Abstract Title: Solid Bupivacaine Deposit Around a Leaking Intrathecal Pump-Catheter Connection

Authors: Balogh S¹, Tegtmeyer S², Schleinzer W³
Swiss Paraplegic Centre Nottwil Switzerland Switzerland¹, ditto ditto ², ditto ditto ³
Poster Type: Poster

ABSTRACT BODY

Objective: A case of solid material of initially unclear composition around a leaking pump-catheter connection is presented.
Case Report: A 58-year-old female with complete paraplegia below L1 had received intrathecal (IT) analgesia for neuropathic pain in the lower extremities via an implanted programmable pump system for nine years. She was admitted due to increasing pain that improved after bolus administration, but not increased dosage. The mixture contained 27 mg bupivacaine HCl, 4.5 mg hydromorphone HCl and 437 μg clonidine HCl per ml; the maintenance dose was 21.5 mg bupivacaine, 4.3 mg hydromorphone and 412 μg clonidine. A contrast study via the side-port showed normal IT distribution with extraneous, sleevelike contrast accumulation around the pump-catheter connection site (Fig.1).
At exploration, the plastic connector was bent and had a visible defect at the end of the side-port. The area was coated with hard, calcified material (Fig.2). There was no sign of local inflammation. The pump was replaced (due to age) and the catheter reattached with a new connector. Both the interior of the pump (Fig.3) and the removed catheter segment showed no sign of drug precipitation. The mass (Fig.4) was hard on palpation but could be easily cut with a scalpel. Chemical analysis showed pure bupivacaine.
Two portions of the pump mixture were stored for three weeks at room temperature and 39°, respectively. Neither showed any sign of precipitate formation.
Discussion: A variety of drug mixtures have been used in recent years for intrathecal analgesia, most commonly opioids and clonidine. The combination with bupivacaine has also proven useful in many cases(1). The stability of a similar, less concentrated mixture in a plastic, external pump reservior(2) and bupivacaine alone(3) and recently at a concentration of 25 mg/ml in combination with morphine 50 mg/ml and clonidine 2 mg/ml over 90 days in an implantable pump system(4) has been demonstrated.
Our patient had had two pump replacements and two catheter revisions during her nine years of IT therapy, all of which required reopening the pump pocket, where the local intraoperative findings were unremarkable. She had lost weight and the pump had shifted lower in the abdominal wall with the side-port directed inguinally, which presumably led to pressure on and then rupture of the connector. The healing process from the surgeries had led to a sleevelike encapsulation of the connection and proximal catheter, which apparently permitted some of the drug mixture to remain in the system and enter the IT space. The extraneous solution presumably became increasingly more concentrated until precipitation occurred. The fact that the mass consisted of pure bupivacaine was probably due to its lower solubility compared to the other two drugs; a local pH effect could also have played a role.
We were not able to find a similar case reported in the literature.
References:
1. Tumber PS and Fitzgibbon DR, Pain 1998;78(3):217-220
2. Wulf H et al. J Pain Symptom Manage 1994;9(5):308-311
3. Hildebrand KR et al., Clin J Pain 2001;17:239-244
4. Classen AM et al., J Pain Symptom Manage 2004;28(6):603-611

ATTACHED FILES

Reg Anesth Pain Med 2005; 30(3):A11