Extravasated Fluid in Hip Arthroscopy and Pain: Is Quadratus Lumborum Block the Answer?

To the Editor We read with interest the article by Haskins et al1 on the use of point-of-care ultrasound to identify intra-abdominal fluid extravasation (IAFE) after hip arthroscopy. The authors found a 16% incidence of IAFE and, most notably, an association with increased postoperative pain and opiate requirements. That association suggests a role for loss of integrity of the hip capsule and/or peritoneal irritation from the intra-abdominal extravasation of irrigation fluid in the not insignificant problem of pain after hip arthroscopy. That 16%, however, may represent only the tip of the iceberg. Branney et al2 found that only 10% of the time were intra-abdominal fluid volumes of <400 mL detected by ultrasound, and that the mean detectable volume was 619 mL. Therefore, if 16% of patients have point-of-care ultrasound-detectable intraperitoneal fluid, then it is likely that a substantial percentage of hip arthroscopy patients have some degree of intra-abdominal extravasation of irrigation fluid. That frequency and the association of IAFE with postoperative pain suggest that this may be an important, common, and heretofore unrecognized component of the pain after hip arthroscopy. Various regional techniques have been reported for postoperative analgesia after hip arthroscopy, including local infiltration, lumbar plexus block, femoral nerve block, fascia iliaca block, and lumbar paravertebral blocks. We have previously reported the use of quadratus lumborum block (QLB) for analgesia after hip fracture repair and total hip replacement.3,4 Our successful experience with QLB for these surgeries has led to its becoming our standard regional technique for them. Based on that experience, we have, for the past year, also used QLB routinely for postoperative analgesia in outpatient hip arthroscopy. The QLB has a number of advantages. It is easy to learn, easy and quick to perform, well tolerated by patients, and avoids side effects such as hypotension, urinary retention, or weakness of quadriceps or hip flexors—all of which promote early ambulation and discharge. Still, the analgesic efficacy of QLB in hip arthroscopy has been something of a pleasant puzzlement. This article by Haskins et al1 struck us as a revelation that may provide the explanation: abdominal/pelvic analgesia in addition to analgesia of the hip (QLB dermatomal coverage typically extends caudally to L2 or L3). A QLB, because it can provide analgesia to the abdomen and pelvis, as well as to the hip, may be uniquely suited to use in hip arthroscopy. Perhaps now we know why. Bruce Ben-David, MDDepartment of AnesthesiologyUniversity of Pittsburgh Medical CenterPittsburgh, Pennsylvania Luca La Colla, MDDepartment of AnesthesiologyDuke University Medical CenterDurham, North Carolina[email protected]