Strengths and Limitations
This study has several strengths.
To the best of our knowledge, this
is the first study that compared 4 types of interventions - SC analgesia
only, IP analgesia only, combined SC and IP analgesia, and no analgesia
at all (placebo). Moreover, the randomized, double- blinded design, as
well as implementing standardized intraoperative and postoperative
protocols for pain relief, has minimized the risk for potential bias.
Lastly, we investigated the effect of preemptive analgesia on
postoperative levels of pain and utilization of medication, including
the demand for opioid-based analgesics.
That said, our study is not free of limitations. To begin with, we only
assessed short-term outcomes, namely the first 24 hours following
surgery, and did not evaluate the full recovery period which culminates
with the patient returning to full activity. However, as no differences
were detected in the first 24 hours, it is unlikely we would have found
any differences in later periods. Another setback is that we did not
evaluate the effect of the various interventions on the time elapsed
until full mobility. Yet, it is important to emphasize that no
thromboembolic events, which are a major concern in non-mobile patients,
were recorded. Lastly, the surgeries included in this study vary in
baseline levels of pain expected, and this variation may be a
confounding factor. However, as mentioned earlier, the groups were not
significantly different as for the frequency of major or minor
surgeries, so it is safe to assume that this had a negligible effect on
the results, if at all.