62 - The Addition of Intrathecal Morphine for Analgesia in Spine Surgery...

#62 The Addition of Intrathecal Morphine for Analgesia in Spine Surgery

Value and Outcomes in Spine Surgery

Poster Presented by: A. Pendi

Author(s):

A. Pendi (1)
F. Acosta (2)
A. Tuchman (2)
R. Movahedi (3)
L. Sivasundaram (4)
I. Arif (1)
G. Gucev (3)

(1) Keck School of Medicine of USC, Global Medicine Program, Los Angeles, CA, United States
(2) Keck School of Medicine of USC, Department of Neurological Surgery, Los Angeles, CA, United States
(3) Keck School of Medicine of USC, Department of Anesthesiology, Los Angeles, CA, United States
(4) Case Western Reserve University, Department of Orthopaedic Surgery, Cleveland, OH, United States

Abstract

Study Design: Meta-analysis of randomized controlled trials (RCTs).

Purpose: Intrathecal morphine (ITM) has been used for decades to provide analgesia in a variety of surgeries. In spine surgery, ITM is of particular interest due to the ease of access to the thecal sac and the potential to provide adequate analgesia at low dosages. As a result, adjunctive ITM has been proposed as a useful supplement to multi-modal and/or PCA-based postoperative pain regimens. However, ITM has been associated with adverse events such as respiratory depression and pruritus. Furthermore, previously published studies have been limited by small sample sizes and conflicting results. This study was conducted with the purpose of evaluating the effectiveness of adjunctive ITM with regards to reducing postoperative pain and morphine equivalent consumption following spine surgery.

Materials and Methods: A systematic search was designed and tailored to each of the following databases: PubMed, Web of Science, Clinicaltrials.gov, and the Cochrane Central Register of Controlled Trials. The aforementioned databases were searched for RCTs. Articles were screened independently by two reviewers based on pre-existing inclusion-exclusion criteria in two stages: title and abstract review and full-text review. Inter-rater agreement was quantified by kappa scores and disputes were resolved by a third party. Postoperative morphine equivalent consumption, pain scores, length of stay, and adverse events were abstracted. Outcomes were compared only if reported by at least three trials. Standard mean differences (SMD) and 95% confidence intervals (CI) were determined for morphine equivalent consumption, pain scores, and length of stay. Odds ratio (OR) and 95% CIs were calculated for adverse events.

Results: Independent screening yielded 8 RCTs that were included in the meta-analysis. Individuals that received ITM (ITM group) as an adjunct to postoperative analgesic were compared to control (control group). Postoperative morphine equivalent consumption (p< 0.001) and pain scores (p< 0.001) were significantly lower in the ITM group within the 24 hours following surgery. However, the ITM group experienced a greater incidence of pruritus (p< 0.001). Respiratory depression was identified in 2.6% of ITM patients. There were no significant differences in terms of sedation (p< 0.18), nausea (p= 0.67), or vomiting (p= 0.62). Although length of stay was lower in the ITM group, this difference was not statistically significant (p= 0.13).

Conclusion: The addition of intrathecal morphine for analgesia significantly reduced morphine equivalent consumption and pain scores in the first 24 hours after spine surgery. However, the ITM group experienced significantly more pruritus. Also, the increased incidence of respiratory depression was of clinical significance. Furthermore, complications such as frequency of cerebrospinal fluid leak could not be analyzed due to not being reported in the included trials. Therefore, future research should consist of high-quality clinical trials with large sample sizes to confirm the effectiveness of adjunctive ITM and broadly report its potential side effects.