Essentials of Our Current Understanding: Abdominal Wall Blocks.

Abdominal wall blocks rely on the spread of local anesthetic within musculofascial planes to anesthetize multiple small nerves or plexuses, rather than targeting specific nerve structures. Ultrasonography is primarily responsible for the widespread adoption of techniques including transversus abdominis plane and rectus sheath blocks, as well as the introduction of novel techniques such as quadratus lumborum and transversalis fascia blocks. These blocks are technically straightforward and relatively safe and reduce pain and opioid requirements in many clinical settings. The data supporting these outcomes, however, can be inconsistent because of heterogeneity of study design. The extent of sensory blockade is also somewhat variable, because it depends on the achieved spread of local anesthetic and the anatomical course of the nerves being targeted. The blocks mainly provide somatic analgesia and are best used as part of a multimodal analgesic regimen. This review summarizes the anatomical, sonographic, and technical aspects of the abdominal wall blocks in current use, examining the current evidence for the efficacy and safety of each.

Role of transversus abdominis plane block after caesarean delivery.

PURPOSE OF REVIEW: The transversus abdominis plane (TAP) block is a relatively new regional anaesthesia technique that has shown analgesic benefit in abdominal and pelvic surgery. There has been recent interest in expanding this regional technique to enhance analgesia following caesarean delivery. RECENT FINDINGS: We will discuss the gross anatomy and neuroanatomy relevant to the TAP, contrast studies looking at the spread of solution within the TAP and the clinical analgesia achieved with the TAP block. We will also present the most recent publications on TAP block analgesia for caesarean delivery and compare the TAP block to intrathecal morphine. SUMMARY: The TAP block significantly improves postoperative analgesia and reduces opioid consumption and opioid-related side-effects in women undergoing caesarean delivery who did not receive intrathecal morphine.

Transversus abdominis plane block.

PURPOSE OF REVIEW: Since the publication of original work on the transversus abdominis plane (TAP) block, the translation of the research into clinical practice has resulted in some 146 articles being published in peer-reviewed journals. However, there continues to be controversies over the best approach to be used. The introduction of ultrasound should have aided the development of this block, but in fact it has caused more questions to be asked. There are a number of reviews of the block already published, but were they published too early and what is our current understanding of the TAP block and its mechanisms of action? RECENT FINDINGS: The TAP block continues to develop. We now understand that the TAP block is a multifaceted block, working with both localized field effects as well as distal effects due to a distant spread of local anesthetic. Recent research would suggest that the location of needle tip placement causes variation in the block characteristics obtained. The more anterior approaches adopted for use since the introduction of ultrasound might be better described as RAFI (regional abdominal field infiltration) blocks. SUMMARY: The TAP block, in all its guises, is an effective analgesic tool, but what is the best approach? Randomized controlled trials comparing the TAP/RAFI blocks to epidural based analgesia are required.

Ipsilateral transversus abdominis plane block provides effective analgesia after appendectomy in children: a randomized controlled trial.

BACKGROUND: The transversus abdominis plane (TAP) block provides effective postoperative analgesia in adults undergoing major abdominal surgery. Its efficacy in children remains unclear, with no randomized clinical trials in this population. In this study, we evaluated its analgesic efficacy over the first 48 postoperative hours after appendectomy performed through an open abdominal incision, in a randomized, controlled, double-blind clinical trial. METHODS: Forty children undergoing appendectomy were randomized to undergo unilateral TAP block with ropivacaine (n = 19) versus placebo (n = 21) in addition to standard postoperative analgesia comprising IV morphine analgesia and regular diclofenac and acetaminophen. All patients received a standard general anesthetic, and after induction of anesthesia, a TAP block was performed using the landmark technique with 2.5 mg · kg(-1) ropivacaine 0.75% or an equal volume (0.3 mL · kg(-1)) of saline on the ipsilateral side to the incision. RESULTS: The TAP block with ropivacaine reduced mean (± SD) morphine requirements in the first 48 postoperative hours (10.3 ± 12.7 vs 22.3 ± 14.7 mg; P < 0.01) compared with placebo block. The TAP block also reduced postoperative visual analog scale pain scores at rest and on movement compared with placebo. Interval morphine consumption was reduced over the first 24 postoperative hours. There were no between-group differences in the incidence of sedation or nausea and vomiting. There were no complications attributable to the TAP block. CONCLUSIONS: Unilateral TAP block, as a component of a multimodal analgesic regimen, provided superior analgesia compared with placebo in the first 48 postoperative hours after appendectomy in children.

The transversus abdominis plane block provides effective postoperative analgesia in patients undergoing total abdominal hysterectomy.

BACKGROUND: Patients undergoing total abdominal hysterectomy suffer significant postoperative pain. The transversus abdominis plane (TAP) block is a recently described approach to providing analgesia to the anterior abdominal wall. We evaluated the analgesic efficacy of the TAP block in patients undergoing total abdominal hysterectomy via a transverse lower abdominal wall incision, in a randomized, controlled, double-blind clinical trial. METHODS: Fifty females undergoing elective total abdominal hysterectomy were randomized to undergo TAP block with ropivacaine (n = 24) versus placebo (n = 26) in addition to standard postoperative analgesia comprising patient-controlled IV morphine analgesia and regular diclofenac and acetaminophen. All patients received a general anesthetic and, before surgical incision, a bilateral TAP block was performed using 1.5 mg/kg ropivacaine (to a maximal dose of 150 mg) or saline on each side. Each patient was assessed postoperatively by a blinded investigator in the postanesthesia care unit and at 2, 4, 6, 12, 24, 36, 48 h postoperatively. RESULTS: The TAP block with ropivacaine reduced postoperative visual analog scale pain scores compared to placebo block. Mean (+/-SD) total morphine requirements in the first 48 postoperative hours were also reduced (55 +/- 17 mg vs 27 +/- 20 mg, P < 0.001). The incidence of sedation was reduced in patients undergoing TAP blockade. There were no complications attributable to the TAP block. CONCLUSIONS: The TAP block, as a component of a multimodal analgesic regimen, provided superior analgesia when compared to placebo block up to 48 postoperative hours after elective total abdominal hysterectomy.

The analgesic efficacy of transversus abdominis plane block after cesarean delivery: a randomized controlled trial.

BACKGROUND: The transversus abdominis plane (TAP) block is an effective method of providing postoperative analgesia in patients undergoing midline abdominal wall incisions. We evaluated its analgesic efficacy over the first 48 postoperative hours after cesarean delivery performed through a Pfannensteil incision, in a randomized controlled, double-blind, clinical trial. METHODS: Fifty women undergoing elective cesarean delivery were randomized to undergo TAP block with ropivacaine (n = 25) versus placebo (n = 25), in addition to standard postoperative analgesia comprising patient-controlled IV morphine analgesia and regular diclofenac and acetaminophen. All patients received a standard spinal anesthetic, and at the end of surgery, a bilateral TAP block was performed using 1.5 mg/kg ropivacaine (to a maximal dose of 150 mg) or saline on each side. Each patient was assessed postoperatively by a blinded investigator: in the postanesthesia care unit and at 2, 4, 6, 12, 24, 36, and 48 h postoperatively. RESULTS: The TAP block with ropivacaine compared with placebo reduced postoperative visual analog scale pain scores. Mean (+/- sd) total morphine requirements in the first 48 postoperative hours were also reduced (66 +/- 26 vs 18 +/- 14 mg, P < 0.001), as was the 12-h interval morphine consumption up to 36 h postoperatively. The incidence of sedation was reduced in patients undergoing TAP blockade. There were no complications attributable to the TAP block. CONCLUSIONS: The TAP block, as a component of a multimodal analgesic regimen, provided superior analgesia when compared with placebo block up to 48 postoperative hours after elective cesarean delivery.

Transversus abdominis plane block: a cadaveric and radiological evaluation.

BACKGROUND AND OBJECTIVES: The abdominal wall is a significant source of pain after abdominal surgery. Anterior abdominal wall analgesia may assist in improving postoperative analgesia. We have recently described a novel approach to block the abdominal wall neural afferents via the bilateral lumbar triangles of Petit, which we have termed a transversus abdominis plane block. The clinical efficacy of the transversus abdominis plane block has recently been demonstrated in a randomized controlled clinical trial of adults undergoing abdominal surgery. METHODS: After institutional review board approval, anatomic studies were conducted to determine the deposition and spread of methylene blue injected into the transversus abdominis plane via the triangles of Petit. Computerized tomographic and magnetic resonance imaging studies were then conducted in volunteers to ascertain the deposition and time course of spread of solution within the transversus abdominis fascial plane in vivo. RESULTS: Cadaveric studies demonstrated that the injection of methylene blue via the triangle of Petit using the "double pop" technique results in reliable deposition into the transversus abdominis plane. In volunteers, the injection of local anesthetic and contrast produced a reliable sensory block, and demonstrated deposition throughout the transversus abdominis plane. The sensory block produced by lidocaine 0.5% extended from T7 to L1, and receded over 4 to 6 hours, and this finding was supported by magnetic resonance imaging studies that showed a gradual reduction in contrast in the transversus abdominis plane over time. CONCLUSIONS: These findings define the anatomic characteristics of the transversus abdominis plane block, and underline the clinical potential of this novel block.

The analgesic efficacy of transversus abdominis plane block after abdominal surgery: a prospective randomized controlled trial.

BACKGROUND: The transversus abdominis plane (TAP) block is a novel approach for blocking the abdominal wall neural afferents via the bilateral lumbar triangles of Petit. We evaluated its analgesic efficacy in patients during the first 24 postoperative hours after abdominal surgery, in a randomized, controlled, double-blind clinical trial. METHODS: Thirty-two adults undergoing large bowel resection via a midline abdominal incision were randomized to receive standard care, including patient-controlled morphine analgesia and regular nonsteroidal antiinflammatory drugs and acetaminophen (n = 16), or to undergo TAP block (n = 16) in addition to standard care (n = 16). After induction of anesthesia, 20 mL of 0.375% levobupivacaine was deposited into the transversus abdominis neuro-fascial plane via the bilateral lumbar triangles of Petit. Each patient was assessed by a blinded investigator in the postanesthesia care unit and at 2, 4, 6, and 24 h postoperatively. RESULTS: The TAP block reduced visual analog scale pain scores (TAP versus control, mean +/- sd) on emergence (1 +/- 1.4 vs 6.6 +/- 2.8, P < 0.05), and at all postoperative time points, including at 24 h (1.7 +/- 1.7 vs 3.1 +/- 1.5, P < 0.05). Morphine requirements in the first 24 postoperative hours were also reduced (21.9 +/- 8.9 mg vs 80.4 +/- 19.2 mg, P < 0.05). There were no complications attributable to the TAP block. All TAP patients reported high levels of satisfaction with their postoperative analgesic regimen. CONCLUSIONS: The TAP block provided highly effective postoperative analgesia in the first 24 postoperative hours after major abdominal surgery.