Modified subcostal approach to anterior quadratus lumborum block for managing postoperative pain in patients undergoing open nephrectomy.

Background: Quadratus lumborum block is a relatively new truncal block and different approaches to this block have been described. With a recent modification to the subcostal approach to the anterior quadratus lumborum block (QLB3), the injection point was moved further cranially and medially, thereby aiming to enhance the spread of the local anesthetic into the thoracic paravertebral space. Although the level of blockade achieved with this modification seems sufficient for open nephrectomy, the modification is still for clinical evaluation. In this retrospective study, we aimed to evaluate the effects of the modified subcostal QLB3 approach on postoperative analgesia.

Methods: All adult patients who received a modified subcostal QLB3 for postoperative analgesia following open nephrectomy between January 2021- 2022 were retrospectively evaluated. Accordingly, total opioid consumption and pain scores during rest/activity within the first 24 h after surgery were evaluated.

Results: A total of 14 patients underwent open nephrectomy were analyzed. Pain scores within the first 6 h postoperatively, particularly the dynamic numeric rating scale (NRS) scores (4-6.5/10), were high. The median (interquartile range) resting and dynamic NRS scores for the first 24 h were 2.75 (1.79) and 3.91 (1.67), respectively. The mean ± standard deviation IV-morphine equivalent dose for the first 24 h was 30.9 ± 10.9 mg.

Conclusions: It was found that the modified subcostal QLB3 did not provide satisfactory analgesia in the early postoperative period. Further randomized studies that extensively investigate the postoperative analgesic efficacy are required to draw a stronger conclusion.