"Inside-out" transversus abdominis plane block.

There is increasing interest nowadays in the use of transversus abdominis plane (TAP) block for perioperative analgesia in general and obstetric surgical cases. In a recent study, we reported that ultrasound (US)-guided TAP block for pain relief following laparoscopic cholecystectomy has led to a significant decrease of systemic analgesics demand compared with a standard general anesthetic.[1] The visibility of different anterior wall planes offered by US technology has opted anesthesiologists to use that approach for perioperative analgesia. Although TAP block is considered simple, safe, and effective, there are two reports of significant morbidity resulting from damage to viscera, namely liver trauma, even when using US-guidance.[23] In an attempt to avoid visceral injury during TAP block, Owen et al., have described a much simpler technique in which the obstetric surgeon, during open surgery, was able to introduce the TAP block via an intra-abdominal approach, which was technically easier and also obviates the risks associated with the conventional TAP procedure.[4] Owen et al. have reported their series in open surgery; we sought of doing TAP block during laparoscopic surgery with retrograde approach or in other words “inside-out” TAP block approach. Theoretically “inside-out TAP” (internal) approach will avoid any possible visceral or vascular trauma compared with the conventional TAP (external) technique. In our case, TAP block was performed under US-guidance with a SonoSite M-Turbo transportable US device (SonoSite™ Inc., Bothell, WA, USA) and a linear 6-13 MHz US transducer. The edge of the probe was covered by a sterile plastic transducer sheath (Intercoverw, Microtek Medical, USA) and a sterile gel (Asept Inmed, Quint Fonsegrives, France) was applied on the skin. Once the abdominal wall muscles were visualized at the level of the anterior axillary line between the 12th rib and the iliac crest then, the surgeon introduced a 50-mm, 19-gauge needle (Nanoline; Pajunk, Geisingen, Germany) through one of the laparoscopic ports [Figure 1]. Once the tip of the needle was placed within the TAP, negative aspiration was performed followed by injection of 15 mL bupivacaine 5 mg/mL with local anesthetic spread appeared on the US screen [Figure 2]. Following needle insertion a 21-gauge catheter was introduced through the needle and fixed to the abdominal wall for continuous TAP block [Figure 3].

Figure 1

Needle insertion

Figure 2

Spread of local anesthetic in the transversus abdominis plane

Figure 3

Catheter insertion

We have described this novel approach of “inside-out” TAP (internal) technique which we think it's safer than the conventional TAP (external) approach for laparoscopic surgery in terms of avoiding visceral or vascular trauma. Furthermore, we believe that continuous “inside-out” TAP block (internal) approach is feasible and may provide more asepsis than the classic TAP (external) approach. Further studies are required to attest our novel approach “inside-out” TAP block.