Analgesic efficacy of postoperative bilateral, ultrasound-guided, posterior transversus abdominis plane block for laparoscopic colorectal cancer surgery: a randomized, prospective, controlled study

Abstract

Background: We assessed whether a postoperative bilateral, ultrasound-guided, posterior transversus abdominis plane (TAP) block could reduce 24 h rescue tramadol requirement compared with placebo in patients undergoing elective laparoscopic colorectal cancer surgery.

Methods: Patients scheduled to undergo elective laparoscopic surgery following the diagnosis of colorectal cancer were included in this study and randomized into Group and Group Control. The patients received a postoperative bilateral, ultrasound-guided, posterior TAP block in either 20 mL of 0.5% ropivacaine (Group TAP) per side or an equivalent volume of normal saline (Group Control). The primary outcome was the cumulative consumption of rescue tramadol within 24 h after the surgery. Secondary endpoints included (1) resting and movement numerical rating scale (NRS) pain scores at 2, 4, 6, 12, 24, 48, and 72 h; (2) incidences of related side effects; (3) time to the first request for rescue tramadol; (4) patient satisfaction regarding postoperative analgesia; (5) time to restoration of intestinal function; (6) time to mobilization; and (7) the length of hospital stay.

Results: In total, 92 patients were randomized, and 82 patients completed the analysis. The total rescue tramadol requirement (median [interquartile range]) within the first 24 h was lower in Group TAP (0 [0, 87.5] mg) than in Group Control (100 [100, 200] mg), P < 0.001. The posterior TAP block reduced resting and movement NRS pain scores at 2, 4, 6, 12, and 24 h after surgery (all P < 0.001) but showed similar scores at 48 h or 72 h. A higher level of satisfaction with postoperative analgesia was observed in Group TAP on day 1 (P = 0.002), which was similar on days 2 (P = 0.702) and 3 (P = 0.551), compared with the Group Control. A few incidences of opioid-related side effects (P < 0.001) and a lower percentage of patients requiring rescue tramadol analgesia within 24 h (P < 0.001) were observed in Group TAP. The time to the first request for rescue analgesia was prolonged, and the time to mobilization and flatus was reduced with a shorter hospital stay in Group TAP as compared with Group Control.

Conclusions: A postoperative bilateral, ultrasound-guided, posterior TAP block resulted in better pain management and a faster recovery in patients undergoing laparoscopic colorectal cancer surgery, without adverse effects.

Trial registration: The study was registered at http://www.chictr.org.cn ( ChiCTR-IPR-17012650 ; Sep 12, 2017).

Keywords: Analgesia technique; Colorectal cancer surgery; Ropivacaine; TAP block.

Fig. 1

Posterior approach of transversus abdominis plane (TAP) block. Note: a The patient was kept in semi-lateral position, the probe position and needle trajectory were displayed. The probe is placed posterior to the midaxillary line between the costal margin and the iliac crest. The needle is inserted in plane. b Corresponding ultrasound images. Posterior approach located in the end of transversus abdominis plane where TAP transmigrate into aponeurosis. The injection site is at the TAP between internal oblique and transversus abdominis posterior to the midaxillary line and near the aponeurosis. White dashed line: needle trajectory. Light blue area: the deposition site of local anesthetic. TA: transversus abdominis; IO: internal oblique; EO: external oblique

Fig. 2

Consort flow study diagram. Note: TAP: transversus abdominis plane

Fig. 3

Kaplan-Meier curve depicting time to first tramadol requirement during postoperative 24-h follow-up among two groups. Note: Group TAP = transversus abdominis plane block, P<0.001

Fig. 4

Comparison of resting NRS scores at different times after surgery between the groups. Note: Mean postoperative resting NRS scores assessed by using an 11-point numerical rating scale (0 = no pain and 10 = the worst imaginable pain) at different times after surgery in each group. *Indicates NRS score significantly difference (P < 0.001, t-test) between two groups. Group TAP = transversus abdominis plane block

Fig. 5

Comparison of movement NRS scores at different times after surgery between the groups. Note: Mean postoperative moving NRS scores assessed by using an 11-point numerical rating scale (0 = no pain and 10 = the worst imaginable pain) at different times after surgery in each group. *Indicates NRS score significantly difference (P < 0.001, t-test) between two groups. Group TAP = transversus abdominis plane block