Spread of injectate after ultrasound‐guided subcostal transversus abdominis plane block: a cadaveric study

Abstract

SummaryUltrasound-guided transversus abdominis plane (TAP) block can be performed using a subcostal technique. This technique was simulated using dye injection in cadavers in order to determine segmental nerve involvement and spread of injectate using either single or multiple-injection techniques. Dye most commonly spread to affect T9 and T10 nerves with the single injection technique and T9, T10 and T11 with multiple injections. The median (IQR [range]) spread of dye was 60 (36-63 [32-78]) cm 2 using the single-injection technique and 90 (85-96 [72-136]) cm 2 , in the multiple-injection technique, and this difference was statistically significant (p = 0.003). These results indicate that ultrasound-guided subcostal TAP block will involve nerve roots T9, T10 and T11 and that a multiple-injection technique may block more segmental nerves and increase spread of injectate. The transversus abdominis plane (TAP) block is a regional anaesthesia technique where local anaesthetic is injected into the neurovascular plane between the transversus abdominis and internal oblique muscles. The ventral rami of the segmental thoracolumbar nerves course through the TAP before innervating the anterolateral abdominal wall. The TAP block has been shown to provide postoperative analgesia following abdominal surgery [1][2][3]. These studies have utilised a landmark technique where the injection point into the TAP is through the lumbar triangle in the lateral abdominal wall [4,5]. The TAP block can also be performed with ultrasound imaging to guide injection of local anaesthetic into the neurovascular plane [6][7][8][9]. Real-time imaging of the needle trajectory and injectate spread may improve both safety and block effectiveness. The goal of the TAP block is to anaesthetise several segmental nerves, and recently, we described the extent of nerve involvement using a dye injection study in a cadaver model that simulated an ultrasound-guided TAP block. The probe was placed on the anterolateral abdominal wall between the iliac crest and the costal margin and the needle advanced from an anterior and medial location in a posterolateral direction so that the needle entry point into the TAP was relatively posterior. Using that approach, thoracolumbar nerves, T11, T12 and L1 were the nerves most commonly affected with dye [10].An alternative ultrasound-guided technique is the subcostal TAP block where the probe is placed immediately inferior to the costal margin on the anterior abdominal wall, and an injection made at this location [11]. As a clinical technique, the subcostal ultrasoundguided TAP block may have a different pattern and extent of segmental nerve involvement compared to the posterior technique; hence the primary objective of this anatomical study was to determine the pattern and extent of injectate spread, as measured by segmental nerve involvement with dye and area of dye spread following a simulated ultrasound-guided subcostal TAP block in cadavers. Ultrasound-guided TAP block can be performed using a single-injection or a mul...

A randomised controlled trial investigating the analgesic efficacy of transversus abdominis plane block for adult laparoscopic appendicectomy

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Transversus abdominal plane block for postoperative analgesia: a systematic review and meta-analysis of randomized-controlled trials

“…1 Since then, numerous variations of this approach have been suggested to overcome the significant variability of local anesthetic spread demonstrated in cadaveric studies. [2][3][4] In recent years, TAP block has gained popularity as an effective pain relief technique in patients undergoing a variety of abdominal operations. An increasing number of randomized-controlled trials (RCTs) and case reports in the literature have highlighted the analgesic effectiveness of the TAP block and proposed it as an alternative pain management technique in patients with contraindications to the use of opioids and/or neuraxial anesthesia.…”

Comparison of analgesic efficacy of oblique subcostal and lateral transversus abdominis plane block after laparoscopic cholecystectomy

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