LAS VEGAS – A laparoscopic transversus abdominis plane (TAP) block is easy to learn, quick to perform, and provides effective postoperative analgesia for women undergoing minimally invasive gynecologic surgeries.
TAP blocks are usually done by an anesthesiologist under ultrasound guidance, Dr. Shanti Mohling said at a meeting sponsored by AAGL. But they can also be performed quite efficiently during a laparoscopic procedure using anatomic landmarks.
“All you need to perform this is a knowledge of the anatomy, a beveled needle with tubing, and two syringes with 20-30 cc of analgesic,” said Dr. Mohling of the University of Tennessee, Chattanooga. “It takes about 3 minutes and it’s very time saving, compared to having an anesthesiologist do this with ultrasound guidance.”
She presented a video of her technique, which relies on identification of the lumbar triangle of Petit to deliver a large volume of anesthetic into the transversus abdominis plane – the neurovascular space between the internal oblique and transversus abdominis muscles. The area is of critical importance to pain sensation, she said. “This plane carries the afferent nociceptor nerves for T7-L1, including the ilioinguinal and iliohypogastric nerves.”
The efficacy of a laparoscopically administered TAP block during laparoscopic gynecologic surgery has been demonstrated in several studies, she noted. One – a review of 61 cases of total laparoscopic hysterectomy - found associations between the use of the TAP black and reduced length of stay and lower opioid consumption (Aust N Z J Obstet Gynaecol. 2011 Dec;51[6]:544-7.).
The video described her technique, beginning with identifying the triangle of Petit. “The triangle of Petit is the area formed between the iliac crest inferiorly, the latissimus dorsi posteriorly, and the external oblique anteriorly. Within this triangle, we find perfect access to the transversus abdominis plane.”
Once the triangle is identified, a beveled needle is advanced slowly, “as to appreciate the ‘double pop sensation’ of the needle as it passes the fascia of the external and internal oblique muscles. Laparoscopically, this can be observed,” Dr. Mohling said. “If the needle can be seen just beneath the peritoneum, then it has penetrated too far.”
Once into the space, which can easily accommodate a large volume of fluid, she delivers the anesthetic into the neurovascular plane. “Importantly, the injectate must be of sufficient volume to effectively spread throughout the neurovascular plane. Typically this requires 20-30 cc on each side,” she said.
Long-acting agents like bupivacaine or ropivacaine are preferable. Dr. Mohling uses a solution of 10 cc liposomal bupivacaine; 10 cc 0.25% bupivacaine; and 10 cc normal saline.
As the anesthetic is injected, it’s important to track it visually to assure correct placement, she noted. “The delivery can be noted laparoscopically by watching a bulge spreading beneath the transversus abdominis fascia.”
The potential for complications is low, but these include intraperitoneal injection; abdominal wall or bowel hematoma; transient femoral nerve palsy; and local anesthetic toxicity.
Dr. Mohling is in the process of conducting a randomized controlled trial of 100 women undergoing planned laparoscopic or robotic hysterectomy. They will be assigned to either TAP block with the liposomal bupivacaine solution or to traditional preincisional local anesthetic with bupivacaine alone.
“I believe we should all add this technique to our practice,” she said. “It’s easy and there is an increasing body of evidence supporting these blocks.”
Dr. Mohling reported having no financial disclosures.