Continuous infusion of opioid and bupivacaine by externalized intrathecal catheters in long-term treatment of "refractory" nonmalignant pain

Objective: To explore the possibility of obtaining pain relief by continuous intrathecal infusion of bupivacaine and opioid in patients with intractable nonmalignant pain. Design: Prospective, cohort, nonrandomized, consecutive trial. Setting: Tertiary care center, institutional practice, hospitalized, and ambulatory care. Patients: A total of 90 patients, 40 men and 50 women, 20 to 96 years old (median, 70 years), with various nonmalignant "refractory" pain conditions lasting for 0.3 to 50 years (median, 3 years) with nociceptive (n = 9), neurogenic/neuropathic (n = 17), and mixed pain (n = 64) were consecutively included in the study when (a) the pain dominated their lives totally, (b) other methods failed to provide acceptable pain relief, and (c) unacceptable side effects from opioids had occurred. Moribund patients and those with overt psychoses at the time of the assessment were excluded from the study. Interventions: (a) Insertion of externalized, tunnelled intrathecal catheters (101 in 90 patients). ib) Intrathecal infusion of opioid (morphine 0.5 mg/ml; or buprenorphine 0.015 mg/ml, and/or bupivacaine 4.75-5.0 mg/ml) from external electronic pumps was started in the operating room at a basic rate of 0.2 ml/hour, with optional bolus doses (0.1 ml 1-4 times/hour) by patient-controlled analgesia (PCA). Thereafter, the daily volumes were tailored to give the patients satisfactory to excellent (60-100%) pain relief, with acceptable side effects from the infused drugs, by increase or decrease of the basic rates and/or of the bolus doses, and their timing. (c) Supervision of the patients for 24 hours after catheterization in the postoperative ward. (d) Daily phone contact with the patients, their families, or the nurses in charge. (e) The patients had ad libitum access to nonopioid analgesics/sedatives and to opioids administered by various routes, until they obtained satisfactory pain and anxiolytic relief. Main Outcome Measures: (a) Pain intensity (visual analog scores 0-10) and pain relief (0-100%). (b) Daily dosages (opioid administered by intrathecal and other routes, and intrathecal bupivacaine). (c) Scores (0-5) of nonopioid analgesics, gait and ambulation; duration of nocturnal sleep, and (d) rates of adverse effects. Results: During the intrathecal period [range, 3-1,706 days; median, 60 days; totaling 14,686 days, 7,460 (50% of which were spent at home)], 86 patients (similar to 95%) obtained acceptable (60-100%) pain relief. The nocturnal sleep duration increased from <4 to 7 hours (median values), nonopioid analgesic and sedative daily consumption became approximately two times lower, whereas the gait ability and ambulation patterns remained practically unchanged. Five patients still had ongoing treatment after durations of 30 to 1,707 (median, 206) days at the close of the study. In the remaining 85 patients, the intrathecal treatment was terminated because of patients' death (n = 23), replacement of the intrathecal treatment by dorsal column stimulation (n = 1), pain resolution (n = 32), refusal to continue the intrathecal treatment (n = 19), lack of cooperation due to delirium or to manipulation of the pump (n = 8), and loss of efficacy of the intrathecal treatment (n = 2). Thus, in the long run, the intrathecal treatment failed in 29 of the 85 patients with terminated treatment (34%). The principal side-effects and complications, except those attributed to the dural puncture, the equipment, and the long-term catheterization of the subarachnoid space, which are presented separately, were severs bradypnea (n = 1), transient paresthesiae (n = 26), short-lasting pareses (n = 16), temporary urine retention(n = 34), episodic orthostatic arterial hypotension (n = 11), anti attempted suicide (n = 5, 3 of which were successful). No neurologic sequelae or death could be attributed to the intrathecal procedure. Conclusions: (a) Intrathecal infusions of opioid and bupivacaine initially provided satisfactory; (60-100%) pain relief in 95% of the patients with "refractory" nonmalignant pain conditions. (b) In the long run, the intrathecal treatment with opioid/bupivacaine failed in 34% of the treated patients (insufficient pain relief 2.3%, lack of patient compliance 9.4%, refusal of further treatment 22.3%).