Perioperative transversus abdominis plane (TAP) blocks for analgesia after abdominal surgery
Abstract
Background
The transversus abdominis plane (TAP) block is a peripheral nerve block which anaesthetises the abdominal wall. The increasing use of TAP block, as a form of pain relief after abdominal surgery warrants evaluation of its effectiveness as an adjunctive technique to routine care and, when compared with other analgesic techniques.
Objectives
To assess effects of TAP blocks (and variants) on postoperative analgesia requirements after abdominal surgery.
Search methods
We searched specialised registers of Cochrane Anaesthesia and Cochrane Pain, Palliative and Supportive Care Review Groups, CENTRAL, MEDLINE, EMBASE and CINAHL to June 2010.
Selection criteria
We included randomised controlled trials (RCTs) comparing TAP block or rectus sheath block with: no TAP or rectus sheath block; placebo; systemic, epidural or any other analgesia.
Data collection and analysis
At least two review authors assessed study eligibility and risk of bias, and extracted data.
Main results
We included eight studies (358 participants), five assessing TAP blocks, three assessing rectus sheath blocks; with moderate risk of bias overall. All studies had a background of general anaesthesia in both arms in most cases.
Compared with no TAP block or saline placebo, TAP block resulted in significantly less postoperative requirement for morphine at 24 hours (mean difference (MD) ‐21.95 mg, 95% confidence interval (CI) ‐37.91 to 5.96; five studies, 236 participants) and 48 hours (MD ‐28.50, 95% CI ‐38.92 to ‐18.08; one study of 50 participants) but not at two hours (all random‐effects analyses). Pain at rest was significantly reduced in two studies, but not a third.
Only one of three included studies of rectus sheath blocks found a reduction in postoperative analgesic requirements in participants receiving blocks. One study, assessing number of participants who were pain‐free after their surgery, found more participants who received a rectus sheath block to be pain‐free for up to 10 hours postoperatively. As with TAP blocks, rectus sheath blocks made no apparent impact on nausea and vomiting or sedation scores.
Authors' conclusions
No studies have compared TAP block with other analgesics such as epidural analgesia or local anaesthetic infiltration into the abdominal wound. There is only limited evidence to suggest use of perioperative TAP block reduces opioid consumption and pain scores after abdominal surgery when compared with no intervention or placebo. There is no apparent reduction in postoperative nausea and vomiting or sedation from the small numbers of studies to date. Many relevant studies are currently underway or awaiting publication.
PICOs
Plain language summary
TAP blocks (nerve blocks) for analgesia after abdominal surgery
Poorly controlled pain after abdominal surgery is associated with a variety of unwanted post‐operative consequences, including patient suffering, distress, confusion, chest and heart problems, and prolonged hospital stays. Traditionally, pain relief is provided by: medications injected in to a vein using a 'drip' such as morphine or paracetamol; administering local anaesthetic into the skin around the surgical wound; or by providing epidural pain relief where local anaesthetic and other pain relieving medications are injected through a fine plastic tube into the epidural space of the lower back ‐ numbing the nerves that supply the abdomen. Following surgery, Transversus Abdominis Plane (TAP) block is a relatively new way of anaesthetising nerves which numb the abdomen after surgery in order to help improve patient comfort after their surgery. In the past few years, there has been increasing research and interest describing how TAP blocks are being used for pain relief in both adults and children having abdominal surgical procedures. However, there have not been any systematic reviews evaluating the effectiveness of the TAP block in reducing pain after surgery. We have searched for research investigating the effectiveness of rectus sheath (a similar block to TAP) and TAP blocks in providing pain relief after abdominal surgery. We have included eight studies, with a total of 358 participants in this review, that show some limited evidence that TAP blocks improve pain relief after abdominal surgery. More research is indicated, comparing TAP blocks with other standard methods of pain relief such as, morphine medication, epidural analgesia and local anaesthetic injection into and around the surgical wound. There are many studies currently underway or awaiting publication which assess the effectiveness of the TAP block and compare it with other techniques. We intend to include these studies in an updated version of this review in the near future.
