VOLUME 29, Issue 1

TAP block is preferred over epidural

The thoracic epidural has been considered “the gold standard” for postoperative analgesia in major abdominal and pelvic surgeries for quite some time. However, transversus abdominis plane blocks (TAP) are becoming more common as an alternative to thoracic epidurals because they are easy to perform under ultrasound guidance and they are associated with fewer side effects and contraindications. Another appealing feature is that patients undergoing TAP blocks can either be managed with a single-shot of local anesthetic or with a continuous infusion via a threaded catheter. This allows TAP blocks to be customizable to meet the needs of a wide variety of patients undergoing surgeries that vary in complexity and duration. Also, a pain-service is not needed for the single shot TAP blocks, which is cost-effective and timesaving. Several recent studies have compared TAP blocks with the thoracic epidural in various types of open abdominal cases and have found that TAP blocks are associated with similar pain scores and opioid consumption. In an effort to avoid continuous infusions and catheters of any kind, a few studies have investigated the effects of liposomal bupivacaine in TAP blocks and show extended duration of analgesia when compared to traditional local anesthetics.

One study performed in the UK compared analgesia over the first 48 hours of continuous four-quadrant TAP blocks with the traditional thoracic epidural in patients undergoing laparoscopic colorectal surgery [1]. The primary outcome measured was the visual analog scale score (VAS) on coughing 24 hours after surgery and the results indicated that there were no significant differences in the two groups. There were also no significant differences between the two groups in postoperative VAS scores at rest, nausea scores, and tramadol consumption over 48 hours. The TAP group also had a higher level of patient satisfaction. Ganapathy performed a similar study in which patients undergoing open abdominal surgery were randomized to receive a thoracic epidural or an ultrasound-guided, continuous, bilateral TAP block for 72 hours postoperatively [2]. The pain scores between the two groups were similar at 24 hours however the TAP group did require more intravenous opioids during surgery and at 24 and 48 hours postoperatively. Five of the 24 patients in the epidural group had significant hypotension, 3 of which needed assessment for ICU care. Kadam had similar findings in a randomized controlled trial, though underpowered, comparing a continuous TAP infusion with epidural in patients undergoing major abdominal surgery with a midline incision [3]. There were no differences in PACU pain scores at 0 and 1 hour nor on the wards on days 1 to 3 at rest or dynamically. The postoperative fentanyl use was also the same in both treatment groups. Hypotension requiring treatment was seen in the epidural group whereas no patients in the TAP group suffered this side effect.

These studies demonstrate that continuous TAP block infusions, when used with multimodal analgesia, can be just as efficacious at pain control as the traditional thoracic epidurals without the associated risks and side effects of an epidural. The goal, ideally, should be to avoid placing catheters altogether in an effort to reduce procedural time and the risk of complications like catheter failure, catheter migration, and infection. Three studies within the past two years have demonstrated superior, longer-lasting analgesia of TAP block when liposomal bupivacaine is used compared to plain bupivacaine. Hutchins conducted a prospective randomized controlled observer-blinded study in patients undergoing robot-assisted hysterectomy comparing bilateral subcostal blocks performed with 0.25% bupivacaine to those performed with 1.3% liposomal bupivacaine [4]. This study found more than a 50% reduction in total opioid use, lower maximum pain scores, and a reduction in nausea during the first 72 hours postoperatively in patients that received a liposomal bupivacaine TAP block. Similar results were found in patients undergoing open abdominal wall reconstructions and laparoscopic hand-assisted nephrectomies [5,6]. Furthermore, patients in the liposomal bupivacaine group had a shorter hospital length of stay, which resulted in overall cost-savings [6].

There is a paucity of data that directly compares thoracic epidurals to TAP blocks with liposomal bupivacaine. One retrospective study funded by Pacira Pharmaceuticals, the maker of Exparel, investigated the hypothesis that the single-shot TAP block is noninferior to continuous epidural analgesia in patients recovering from major lower abdominal surgery [7]. They also tested the hypothesis that both TAP infiltration and epidural analgesia provide better post-operative analgesia than IV PCA. The results indicate that TAP infiltration with liposomal bupivacaine was non-inferior to epidural catheters for both pain and opioid consumption in the 72-hour postoperative period.

In summation, ultrasound-guided TAP blocks have shown to be an effective alternative to epidurals in patients undergoing major abdominal surgery. Studies have shown comparable pain scores and similar rates of opioid consumption between the two postoperatively. Single shot TAP blocks are not associated with hypotension, are easier and safer to perform, can be placed in anticoagulated patients, and do not require a labor-intensive pain service for management. The one shortcoming is the shorter duration of action in patients requiring additional analgesia. Liposomal bupivacaine shows promise as a solution to this problem as the limited data indicates that it can extend the duration of a TAP block through 48-72 hours postoperatively. Large randomized controlled trials directly comparing thoracic epidurals with liposomal bupivacaine TAP blocks are warranted. Until then, TAP blocks should be utilized more as a safe and effective modality to treat post-operative pain in major abdominal surgery.

Lisa Mouzi Wofford, MD

References

[1] Niraj G, Kelkar A, Hart E, Horst C, Malik D, Yeow C, Singh B, Chaudhri S. Comparison of analgesic efficacy of four-quadrant transversus abdominis plane (TAP) block and continuous posterior TAP analgesia with epidural analgesia in patients undergoing laparoscopic colorectal surgery: an open-label, randomised, non-inferiority trial. Anaesthesia. 2014 Apr;69(4):348-55.

[2] Ganapathy S, Sondekoppam RV, Terlecki M, Brookes J, Das Adhikary S, Subramanian L. Comparison of efficacy and safety of lateral-to-medial continuous transversus abdominis plane block with thoracic epidural analgesia in patients undergoing abdominal surgery: A randomised, open-label feasibility study. Eur J Anaesthesiol. 2015 Nov;32(11):797-804.

[3] Kadam VR, Van Wukf RM, Morani JL, Miller D. Epidural versus continuous transversus abdominis plane catheter technique for postoperative analgesia after abdominal surgery. Anaesth Intensive Care 2013; 41: 476-481

[4] Hutchins J, Delaney D, Vogel RI, Ghebre RG, Downs LS Jr, Carson L, Mullany S, Teoh D, Geller MA. Ultrasound guided subcostal transversus abdominis plane (TAP) infiltration with liposomal bupivacaine for patients undergoing robotic assisted hysterectomy: A prospective randomized controlled study. Gynecol Oncol. 2015 Sep;138(3):609-13.

[5] Fayezizadeh M, Majumder A, Neupane R, Elliott HL, Novitsky YW. Efficacy of transversus abdominis plane block with liposomal bupivacaine during open abdominal wall reconstruction. Am J Surg. 2016 Sep;212(3):399-405.

[6] Hutchins JL, Kesha R, Blanco F, Dunn T, Hochhalter R. Ultrasound-guided subcostal transversus abdominis plane blocks with liposomal bupivacaine vs. non-liposomal bupivacaine for postoperative pain control after laparoscopic hand-assisted donor nephrectomy: a prospective randomised observer-blinded study. Anaesthesia. 2016 Aug;71(8):930-7.

[7] Ayad S, Babazade R, Elsharkawy H, Nadar V, Lokhande C, Makarova N, Khanna R, Sessler DI, Turan A. Comparison of Transversus Abdominis Plane Infiltration with Liposomal Bupivacaine versus Continuous Epidural Analgesia versus Intravenous Opioid Analgesia. PLoS One. 2016 Apr 15;11(4):e0153675.