Whether epidural analgesia is a better method than parenteral opioids
for postoperative pain control remains controversial.
To systematically review the efficacy of postoperative epidural analgesia
vs parenteral opioids, the primary alternative technique.
Studies were identified primarily by searching the National Library
of Medicine's PubMed database (1966 to April 25, 2002) and other sources for
studies related to postoperative epidural analgesia.
Inclusion criteria were a comparison of epidural therapy vs parenteral
opioids for postoperative analgesia, measurement of pain using a visual analog
scale (VAS) or numeric rating scale, randomization of patients to either therapy,
and adult patients (≥18 years). A total of 1404 abstracts were identified,
100 of which met all inclusion criteria.
Each article was reviewed and data extracted from tables, text, or extrapolated
from figures as needed. Weighted mean pain scores, weighted mean differences
in pain score, and weighted incidences of complications were determined by
using a fixed-effect model.
Epidural analgesia provided better postoperative analgesia compared
with parenteral opioids (mean [SE], 19.40 mm [0.17] vs 29.40 mm [0.20] on
the VAS; P<.001). When analyzed by postoperative
day, epidural analgesia was better than parenteral opioids on each postoperative
day (P<.001 for each day after surgery). For all
types of surgery and pain assessments, all forms of epidural analgesia provided
significantly better postoperative analgesia compared with parenteral opioid
analgesia (P<.001 for all), with the exception
of thoracic epidural analgesia vs opioids for rest pain after thoracic surgery
(weighted mean difference, 0.6 mm; 95% confidence interval, –0.3 to
1.5 mm; P = .12). The complication rates were lower
than expected for nausea or vomiting and pruritus but comparable with existing
data for lower extremity motor block.
Epidural analgesia, regardless of analgesic agent, location of catheter
placement, and type and time of pain assessment, provided better postoperative
analgesia compared with parenteral opioids.