Had some mix results on tap blocks for lap cholecystectomy and hernia surgeries While visualization of structures is not a problem, where exactly is the correct place of the needle for dissection? Do you want your needle to go through the fascia layer between IO and trans abdominal muscle, depositing local ontop of the trans abdominal muscle? Is the needle to be positioned in the fascia? Should the patient have a numbness to the skin like other blocks? Do the anterior sensory nerves lye ontop of the muscle belly or within the fibers connective aponeurosis?
Thanks for your comment. My best explanation is that a successful TAP can be anticipated with injection within the plane ("fishmouth" spread pattern or plane obliteration) or through the plane (concave up spread pattern). If you see a concave down spread pattern it indicates you are not deep enough, as I understand the spinal segmental nerves lie on the deep side of the TAP plane. Unlike other blocks, TAP blocks often have an inconsistent dermatomal pattern of numbness so this can not always be used as a good predictor of block success. Remember with lap choles (and other surgeries above the umbilicus) to use a subcostal approach to get the higher dermatomes. Cheers- Brandon
What do you use as your best indicator of success , pain scores?
Therein lies one of the challenges of TAP blocks in my opinion. Unless you are doing them as a rescue block where every patient in pain is their own control group (pain before vs. pain after), pre-op TAP block placements are hard to assess for success. Sometimes you get perfect spread and they have significant pain in the PACU, and sometimes the image is terrible and they are pain free. And pain scores are not a perfect measure of success for pre-op placed TAP blocks since visceral pain is not covered by the block and is like a confounding variable. So pre-op TAP blocks are a bit of a leap of faith each time they are placed; we rely on published data to demonstrate their benefits in general while not always being able to assess their success in individual patients.