Analysis of breakthrough pain in 50 patients treated with intrathecal morphine infusion therapy. Development of tolerance or infusion system malfunction.
Fifty patients with intractable benign pain were treated with intrathecal morphine (IT-MS) infusion therapy. Median follow-up was 39 months (range 5-70). Breakthrough pain was reported in 45 (90%) patients in 75 outpatient clinic events. A diagnostic algorithm was developed to evaluate and efficiently treat these patients. A programmed bolus (50% of daily dose) identified that 50 (67%) breakthrough events where due to partial tolerance to the IT-MS. Radiographic survey of the catheters identified malfunctions in 11 patients. Attempts to withdraw CSF from the side-port demonstrated obstruction in 7 due to kinking not seen on X-rays. Side-port myelography demonstrated scarring that obstructed the flow of morphine to the spinal cord in 2 patients. Benefits were regained after all surgical catheter corrections. In total, partial tolerance was seen in 23 patients (46%) during 50 (67%) breakthrough events, 15 patients (30%) required 22 catheter revisions during 27% of breakthrough events and 2 patients had progressive disease. True tolerance was encountered in only 5 patients (10%) during 5 (7%) breakthrough pain events.
Department of Neurosurgery, West Virginia University, Morgantown, USA.
S
S
Bloomfield
J
J
Hogg
O
O
Ortiz
R
R
Gross
D000328:Adult; D000368:Aged; D004305:Dose-Response Relationship, Drug; D004361:Drug Tolerance; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage* / Q000627:therapeutic use; D010148:Intractable Pain / Q000503:physiopathology*; D010166:Palliative Care; D016896:Treatment Outcome
D009020:Morphine