Is L2 Paravertebral Block Comparable to Lumbar Plexus Block for Postoperative Analgesia After Total Hip Arthroplasty?

Abstract

Background Continuous lumbar plexus block (LPB) is a well-accepted technique for regional analgesia after THA. However, many patients experience considerable quadriceps motor weakness with this technique, thus impairing their ability to achieve their physical therapy goals. Questions/purposes We asked whether L2 paravertebral block (PVB) provides better postoperative analgesia (defined as decreased postoperative opioid consumption and lower pain scores), better preservation of motor function, and decreased length of hospital stay (LOS) compared to LPB in patients undergoing THA. Methods Sixty patients undergoing minimally invasive THA under standardized spinal anesthesia were enrolled in this randomized controlled study. After exclusions, 53 patients were randomized into the L2 PVB (n = 27) and LPB (n = 26) groups. Patient-controlled analgesia was available for 24 hours. Motor and pain assessments were performed in the recovery room and at the end of 24 hours. LOS was also noted. Results Postoperative opioid consumption during the first 24 hours was less in the LPB group (mean ± SD: 24 ± 15 mg morphine) than in the L2 PVB group (32 ± 15 mg morphine; p = 0.005); however, postoperative pain scores were not different between groups. Postoperative motor and rehabilitation outcomes and LOS were also similar. Conclusions Our study demonstrates that use of a LPB results in slightly less morphine consumption but comparable pain scores when compared with continuous L2 PVB. No difference was noted in terms of motor preservation or LOS. Although the difference in morphine consumption was only slightly in favor of the LPB group, the advantage of L2 PVBs noted by previous authors as preservation of motor function, was not seen. At our institute where LPBs have been performed for years, there seems to be no real advantage in switching to L2 PVBs. However, L2 PVB could be a reasonable alternative for operators who are wary of LPBs due to their high potential for complications and/or requiring advanced skills for its placement. But, since L2 PVBs are relatively new, not much is known about their complication profile. We recommend a thorough understanding of both techniques before attempting to place them.

Unexpected motor weakness following quadratus lumborum block for gynaecological laparoscopy

“…Lumbar paravertebral block at the L1–2 level has also been demonstrated to cause motor weakness, with a case report of L1 and L2 paravertebral blocks for analgesia for hip arthroscopy noting ‘weakness of thigh flexion and knee extension (4/5 power)’ using 5 ml ropivacaine 0.5% at each level . A study comparing lumbar plexus block and L2 paravertebral block with 15 ml ropivacaine 0.5% for total hip arthroplasty showed a similar reduction in hip flexion strength between the two groups postoperatively .…”

The Role of Paravertebral Blocks in Ambulatory Surgery: Review of the Literature

“…Lumbar PVB is applied 2.5 cm away from the spinous process at the level of the lumbar spinal nerve roots (lumbar 1 to 4) with a combination of nerve stimulator and ultrasound use, such that the patient is positioned in a lateral supine position, with the non-operative side being dependent, with the legs flexed at the hips and the patella and muscles of the upper leg visible to the eye of the operator. Indications for lumbar PVB are analgesia for hip and knee surgery, paediatric orthopaedic procedures, vaginal delivery, and femoropopliteal bypass surgery ( 27 , 28 ). It is often compared with lumbar plexus block ( 27 ).…”

“…Indications for lumbar PVB are analgesia for hip and knee surgery, paediatric orthopaedic procedures, vaginal delivery, and femoropopliteal bypass surgery ( 27 , 28 ). It is often compared with lumbar plexus block ( 27 ). PVB is contraindicated if there are infections at the intended block application site, history of allergy to local anaesthetics, tumours that infiltrate the paravertebral space and patient refusal.…”

Update on paravertebral blocks

“…Previous case reports [18] have discussed the advantage of lumbar paravertebral blocks in preserving quadriceps in hip arthroscopy. A recent study by Wardhan et al compared quality of analgesia between continuous lumbar plexus block and continuous L2 PVB after total hip arthoplasty [19]. Even though the study demonstrated the equivalent analgesia between the L2 PVB and the lumbar plexus group, the L2 PVB failed to demonstrate motor preservation [19].…”

“…Per the guidelines published by the Eastern Association for the Surgery of Trauma in 2007, epidural analgesia is considered the gold standard for managing rib fracture pain. Epidural analgesia is, however, limited by its narrow applicability to rib fracture patients and related side-effects [23]. In addition, many trauma patients, for multiple reasons such as cervical neck fractures, lumbar-thoracic spine fractures, and altered mental status, are not candidates for epidural analgesia [24].…”