Postoperative pain management is an integral part of achieving the goals of ERPs after colorectal surgery. TAP blocks are an attractive approach for minimizing the use of opioids, especially given their low risk of adverse effects. Although usually done preoperatively, our study showed that postoperative TAP block with nonliposomal bupivacaine appeared to be at least as efficacious as preoperative TAP block in reducing postoperative intravenous narcotics use, both PCA and administered intravenous injections. Furthermore, postoperative nonliposomal TAP block was associated with a reduced total amount of prescription opioids needed to the time of discharge from the hospital. Other variables such as length of stay, estimated operative blood loss, procedure length, reoperation and readmission rates did not differ between preoperative or postoperative administration of the TAP.
The effectiveness and feasibility of TAP blocks in colorectal surgery has been shown in multiple studies [10–15]. In a randomized, placebo-controlled clinical trial, Tikuisis et al. showed that patients who received ropivacaine TAP blocks had significantly lower pain scores at 2, 4, and 12 hours at rest, and at 2 and 4 hours during movement. The TAP group also used significantly less fentanyl and ketorolac following a hand-assisted laparoscopic left hemicolectomy for colon cancer compared to those who received placebo . Pirrera et al. compared the use of preoperative ropivacaine TAP block vs thoracic epidural analgesia in patients before elective laparoscopic colon resection. Both patient groups were a part of a standard enhanced recovery after surgery pathway. Albeit a case-control study, pain control was comparable between the 2 groups. Additionally, the TAP group had significantly lower rates of postoperative nausea, vomiting, ileus, and paresthesia. There was no significant difference in hospital length of stay or 30-day readmission rate. In a prospective, randomized, double-blind study, Keller et al. assessed the effect of TAP blocks on postoperative pain in patients following laparoscopic colorectal resections. Compared to their counterparts, the TAP group had significantly lower pain scores and used fewer opioids. However, there was no difference in hospital length of stay and readmission rate between the groups . These research study findings are consistent with our current results.
Given that TAP block is both feasible and effective for optimizing pain control after colon surgery, it is important to assess whether the additional cost of using liposomal bupivacaine is justified. Liposomal bupivacaine, an extended-release version, increases the duration of action of plain bupivacaine . Past industry sponsored studies have shown liposomal bupivacaine to be more effective than plain bupivacaine in controlling pain after colectomy, resulting in fewer narcotics use, faster return of bowel function, and shorter length of stay [16–18]. However, in a non-sponsored, prospective, randomized double-blind clinical trial, Knudson et al. found no significant difference in hydromorphone PCA use in the first 2 postoperative days for patients who received liposomal vs plain bupivacaine after colorectal resections . Liposomal bupivacaine is more expensive than plain bupivacaine and hence is not readily available on hospital formulary [8, 20]. For these reasons, it is rational to consider plain bupivacaine and adjustment of timing as another way to maximize pain control. Our study showed that using plain bupivacaine after surgery was not inferior to preoperative administration and may still provide benefit in terms of PCA use and total narcotic used after colectomy.
Considering the shorter duration of action of plain bupivacaine, the timing of its administration for TAP blocks may provide the needed analgesia while mitigating cost. Preoperative administration is easily performed in the preoperative area and does not affect surgical planning such as ostomy procedures. It is also in line with preemptive analgesia. Oliveira et al., through a meta-analysis that included a variety of abdominopelvic surgeries, reported a greater postoperative pain control, reduced pain at rest, and decreased opioid used with preoperative TAP compared to placebo or no treatment . The majority of the TAP blocks performed in our study were performed preoperatively, but we found benefit with postoperative TAP blocks. While the numbers are small in the postoperative TAP group, the postoperative TAP group did not show inferior pain control compared to preoperative administrated block. In fact, our results showed that plain bupivacaine TAP administered postoperatively led to a reduced postoperative intravenous narcotic use and lesser amount of discharge prescription narcotics.
The study was limited by its retrospective design, the small number of patients who received postoperative nonliposomal bupivacaine TAP block procedures, and by having been performed in a single center. Although the TAP blocks were performed by, or under supervision of, the attending anesthesiologists who specialize in acute pain management and regional anesthesia, we acknowledge the possibility that performer-related differences could lead to differences in pain relief. However, our results showed that some of the additional cost of using liposomal bupivacaine may be offset by performing nonliposomal TAP blocks after the surgical resection. Finally, our study did not directly measure the patient pain scores. Instead, we used the amount of postoperative narcotics used as a surrogate for the adequacy of pain control. Per our ERP, additional analgesia is prescribed on an as-needed basis and coincides with the patient’s assessment of pain on a numeric scale.