Intrathecal morphine infusion for chronic non-malignant pain: a multiple center retrospective survey

Intrathecal morphine (ITM) is commonly used for the treatment of cancer pain. There is reluctance for its use in France to treat chronic noncancer pain. In order to appreciate its popularity, efficacy, dose escalation with time, and long-term tolerance, we carried out a retrospective study in the neurosurgery departments of university teaching hospitals in France involved in intrathecal drug therapy. Only 44 patients with chronic noncancer pain used implanted pumps for ITM treatment. Nineteen patients were available for detailed analysis. This survey concerns these 19 patients. There were 13 women and six men. Their average age was 48.8 years (range: 30-69 y). The mean duration of pain before pump implantation was 100 months (range: 12-240 m). The mean follow-up since implantation was 54 m (range: 4-144 m). Thirteen patients were suffering from postsurgery lumbar and radicular pain. The average initial and final dose per day of morphine was 1.3 mg (range: 1-2 mg) and 2.5 mg (range: 1-6.7 mg) for patients with nociceptive pain and 1.2 mg (range: 0.7-2 mg) and 3 mg (range: 1-10 mg) for patients with mixed pain, respectively. Five (26.3%) of 19 patients returned to their initial jobs. Increase in activity level was reported as good in seven patients (36.8%). Patient satisfaction rate was 90%. The VAS rate was reduced to 49.2% of the initial values while the subjective pain relief was estimated at 67.8%. Two cases (10.5%) of late pump site infection and two patients (10.5%) with catheter displacements were recorded. Side effects imputable to morphine included; constipation, somnolence, decreased libido, weight gain, amenorrhoea, vomiting, nightmares, and itching. No development of tolerance or addiction were recorded. We conclude that in well selected cases ITM should be considered as a possible therapeutic option in the treatment of intractable chronic benign pain.