A Randomized, Double Blind, Placebo Controlled Evaluation Trial of the Benefit in Quadratus Lumborum Block as a Postoperative Analgesic Technique for a Lumbar Spine Decompression and Fusion Surgery

Spinal decompression is a surgical procedure that is performed to alleviate pain caused by pinched nerves (neural impingement). Surgical options for decompressing the lumbar spine vary from minimally invasive disc decompression to open laminectomy and foraminotomy. The lumbar spine decompression and fusion differs from a microdiscectomy in that the incision is longer and there is more muscle stripping. Lumbar spinal decompression is a commonly performed procedure and the conventional open techniques of decompression remain the gold standard of treatment.

During a lumbar decompression back surgery, a small portion of the bone over the nerve root and/or disc material from under the nerve root is removed to give the nerve root more space and provide a better healing environment. A lumbar spine decompression and fusion is typically performed to relieve the lumbar spinal stenosis symptoms. The goal of the surgery is to allow more space for the nerve root, thus reducing pain (and potentially any leg weakness or neurological symptoms) and restoring the patient's ability to participate in everyday activities[1].

Quadratus lumborum (QL) block was introduced in 2007 and is performed for perioperative pain management in various abdominal, pelvic, gynecological and hip procedures in all age groups[2]. Four types of QL block were described, differentiated by the exact location of the anesthetic injection. Type 1/lateral QL block is performed at the lateral border of the QL muscle, type 2/posterior QL block is performed at the medial edge of the QL muscle (at the border or the spine erector muscles and the thoraco-lumbar fascia), type 3/anterior is performed between the QL muscle and the psoas major and type 4 is intramuscular (see figure 1). In the majority of cases, these blocks are performed pre/post operatively under ultrasound guidance. There are sporadic reports of QL block performed for lumbar spinal surgery [3, 4].However, the plane for a type 2 QL block can be easily reached during open midline spinal surgery.

The importance of pain control in the postoperative period for spinal surgery has been discussed and proven extensively, with both immediate and delayed reduction in complications and improved clinical results [5, 6].

The investigators hypothesize that the type 2 QL block is an effective analgesic tool for lumbar laminectomy surgery, because in lumbar laminectomy the quadratus lumborum is already exposed and is in direct visual contact. For that reason it is imperative, in our opinion, to test its benefits of this procedure.