Intrathecal morphine for analgesia in children undergoing selective dorsal rhizotomy

Abstract

Selective dorsal root rhizotomy is performed for relief of spasticity in children with cerebral palsy. Postoperative pain relief can be provided by intrathecal morphine administered at the time of the procedure. We sought to define an optimal dose of intrathecal morphine in children undergoing selective rhizotomy, through a randomized, double-blinded prospective trial. After institutional approval and parental written informed consent, 27 patients, ages 3-10 years, were randomized to receive 10, 20, or 30 micrograms.kg-1 (Groups A, B, and C, respectively) of preservative-free morphine administered intrathecally by the surgeon after dural closure. Postoperatively, vital signs, pulse oximetry, and pain intensity scores were recorded hourly for 24 hr. Supplemental intravenous morphine was administered postoperatively according to a predetermined schedule based on pain scores. There was considerable individual variability in the time to initial morphine dosing and cumulative supplemental morphine dose. Time to first supplemental morphine dose was not different between groups. When compared to Groups A and B, cumulative 6-hr supplemental morphine dose was significantly lower in Group C (38.6 +/- 47 micrograms versus 79.1 +/- 74 and 189.6 +/- 126 for Groups A and B, respectively). By 12 hr, cumulative supplemental morphine dose was similar in Groups A and C. Group B consistently had a higher supplemental dose requirement than Groups A and C at 6, 12, and 18 hr. By 24 hr, there was no difference in cumulative dose among groups. Postoperative pain scores and the incidence of respiratory events, nausea, vomiting and pruritus were comparable among groups. These data suggest that intrathecal morphine at 30 micrograms.kg-1 provides the most intense analgesia at 6 hr following selective dorsal root rhizotomy, but was otherwise comparable to the 10 micrograms.kg-1 dose.

Postoperative continuous intrathecal pain treatment in children after selective dorsal rhizotomy with bupivacaine and two different morphine doses

“…alone gave itching in 56% of children (34). The general incidence of pruritus found in this study was low compared with other studies (7,9,31) and one reason could be our use of ondansetron to treat PONV. Previous studies have shown that ondansetron is effective in treating spinal morphine‐induced pruritus (16,26,35), and all children in the low‐dose group and 73% of the children in the high‐dose group received ondansetron.…”

Morphine with or without a local anaesthetic for postoperative intrathecal pain treatment after selective dorsal rhizotomy in children

“…IT morphine has not been found to affect the haemodynamic parameters ( 5). One could expect a lower systemic blood pressure in the bupivacaine/morphine group due to the sympathetic blockade.…”

“…The use of morphine IT has been shown to provide a long duration of postoperative analgesia and it has been described for a variety of surgical procedures (4,5,8±11). Harris et al (4) report the duration of analgesia to be 3±48 h and, in the study by Dews et al (5), the pain relief was 1±15 h depending on the dose. The half-life of morphine in cerebrospinal¯uid (CSF) is similar in plasma (12).…”

Selective Dorsal Rhizotomy and Postoperative Pain Management

“…Our experience is that postoperative pain treatment in these children can be demanding, not only due to postincision pain from the lumbar laminotomy, but also due to dysesthesia of the lower extremities caused by manipulation of the nerve rootlets [8,24,25,26,27,28,29,30]. During the 1980s, it is most probable that these children were treated with conventional intravenous and/or oral regimes.…”

“…During the last two decades, various pain treatment strategies have been published for children undergoing SDR. Both ED [25, 29] and IT opioids [28, 30, 31] have been used as an effective and safe pain therapy. Continuous intravenous morphine infusion has been reported as an option [27].…”