Current trends in perioperative pain management stress the importance of multimodal analgesia in an effort to reduce the dependence on opioid pain medications. Adverse effects of opioids include sedation, respiratory depression, nausea, vomiting, constipation, itching, and, most importantly, the potential for tolerance and abuse. Multimodal analgesia attempts to utilize multiple techniques, including medications and nerve block procedures, to improve postoperative analgesia. Improved postoperative pain control can enable an earlier return to normal activities for patients, not only improving patient satisfaction, but also reducing postoperative morbidity and adverse effects of opioids.
Approximately 350,000 to 500,000 ventral hernia repairs are performed each year in the United States. Surgeries completed laparoscopically are typically performed on an outpatient basis, allowing patients to return home the same day of surgery and treat their pain independently with prescribed pain medications. Utilization of a regional anesthesia technique may allow prolonged numbing of the nerves postoperatively and decrease the reliance on oral pain medications. Transversus abdominis plane (TAP) blocks have been shown to decrease pain scores and opioid consumption following ventral hernia repair. Quadratus lumborum (QL) blocks are newer iterations of the TAP block.
There are currently three types of the QL block, all targeting the thoracolumbar fascia surrounding the quadratus lumborum muscle. Injection within this fascial plane may allow local anesthetic spread into the paravertebral space, possibly explaining why QL blocks have been mapped from the T7 to T12/L1 dermatomes, covering the entire abdomen. Conversely, TAP blocks have been mapped from the T10 to T12/L1 dermatomes, only covering the abdomen below the umbilicus. In the first, the Quadratus lumborum 1 block (QL1), the local anesthetic is injected within the fascial plane lateral to the QL muscle. In the second, the Quadratus lumborum 2 block (QL2), the needle trajectory is more superficial, and the local anesthetic is injected along the posterior border of the QL muscle. The third iteration, the Quadratus lumborum 3 block (QL3), involves a deeper, transmuscular approach with injection along the anterior border of the QL muscle. Our study would utilize the QL2 approach as the dermatomal distribution of the QL1 and QL2 blocks appear to be more widespread than the QL3 block, and the QL2 block may be a safer approach due to the more superficial angle of the needle 3.
Additionally, the QL block has been shown to have a longer duration of analgesia when directly compared to the TAP block. A study of pediatric lower abdominal surgery revealed improved pain scores and parent satisfaction with care in the QL group compared to TAP block. This improvement persisted to the 24 hour mark. In a study of postoperative pain following cesarean delivery, pain scores were improved and opioid consumption decreased with the QL block compared to the TAP block. The differences were not significant at the 1 and 6 hour marks, but were significant at the 12, 24 and 48 hour marks, highlighting the analgesic duration of the QL block 8.
This study aims to evaluate the efficacy of the QL block using the QL2 approach on recovery profile after laparoscopic ventral hernia repair, a commonly performed surgery, as well as contribute to the understanding of the block and its distribution of anesthesia.
