Multifidus Plane Block for Lumbar Spine Surgery
The multifidus plane block (also called sub-multifidus block or SMFB) is an emerging regional anesthesia technique for lumbar spine surgery, but the erector spinae plane block (ESPB) has stronger evidence and should be the preferred regional technique when nerve blocks are indicated for postoperative pain management in lumbar spine surgery. 1, 2, 3, 4
Evidence for Regional Blocks in Lumbar Spine Surgery
Erector Spinae Plane Block (ESPB) - The Better-Studied Option
The ESPB has robust evidence demonstrating significant benefits:
Bilateral lumbar ultrasound-guided ESPB with 0.375% ropivacaine 40 mL provides superior postoperative analgesia compared to local wound infiltration, with NRS pain scores of 1.9±1.5 versus 5.9±1.6 (p<0.001) in the immediate postoperative period 1
ESPB significantly reduces 24-hour opioid consumption by approximately 40-60% compared to standard analgesia, with total sufentanil consumption of 10±3 tablets versus 17±6 tablets (p<0.001) 1, 2, 3, 4
Pain scores remain significantly lower at 6,12, and 24 hours postoperatively with ESPB compared to controls 3, 4
Hospital length of stay is reduced, with 73.3% of ESPB patients discharged by 72 hours versus 100% of control patients requiring longer stays (p=0.005) 1
The technique is performed preoperatively under ultrasound guidance at the low thoracic level (typically T9-T12 for lumbar surgery) in the prone position after induction of general anesthesia 3, 4
Multifidus Plane Block (SMFB) - Limited Evidence
The sub-multifidus block is a newer technique with minimal published data:
Only a small case series of 15 patients exists describing ultrasound-guided injection of local anesthetic deep to the multifidus muscle, which provided "good quality analgesia" without adverse events 5
The technique targets dorsal rami of spinal nerves at multiple levels by injecting beneath the multifidus muscle and medial to the transverse process 5
No comparative trials exist evaluating SMFB against standard care or other regional techniques 5
Recommended Multimodal Analgesia Framework
Regional blocks should be integrated into a comprehensive multimodal approach:
Foundation Medications (Administer Preemptively)
NSAIDs and acetaminophen form the cornerstone of perioperative pain management and should be given preoperatively 6
Short-term NSAID use (<2 weeks) is safe for spinal fusion, with no level 1 evidence linking NSAIDs to reduced fusion rates in studies after 2005 7
Gabapentinoids
Pregabalin (150-300 mg) or gabapentin (≥900 mg/day) given preoperatively and continued postoperatively significantly reduces pain scores, opioid consumption, and opioid-related side effects (nausea, vomiting, pruritus) 7, 6
Higher gabapentin doses (>900 mg/day) show dose-dependent benefits including reduced morphine consumption and urinary retention 7
Local Anesthetic Infiltration
Bupivacaine wound infiltration provides immediate postoperative relief, with liposomal formulations extending duration up to 96 hours 7, 6
Evidence for local infiltration in spine surgery is mixed, with some studies showing benefit and others failing to demonstrate superiority over standard care when combined with adequate multimodal analgesia 7
Opioid Limitations
Limit opioids to maximum 7 days to avoid respiratory depression, tolerance, and addiction risk 6
Use patient-controlled analgesia (PCA) for breakthrough pain in the immediate postoperative period 7
Clinical Algorithm for Regional Block Selection
When considering regional anesthesia for lumbar spine surgery:
First-line regional technique: Bilateral ultrasound-guided ESPB with 0.375% ropivacaine 40 mL total (20 mL per side) at T9-T12 level, performed preoperatively after induction 1, 3, 4
Alternative if ESPB unavailable or contraindicated: Local wound infiltration with bupivacaine 0.5% or liposomal bupivacaine 7, 6
Do not use multifidus plane block routinely until comparative trials demonstrate equivalence or superiority to ESPB 5
Always combine regional techniques with multimodal analgesia including preemptive NSAIDs, acetaminophen, and gabapentinoids 6
Important Caveats and Pitfalls
ESPB analgesic effects may diminish after 6-8 hours with single-shot technique, requiring supplemental analgesia 8
Bupivacaine carries higher cardiotoxicity risk than other local anesthetics, though complications from local infiltration are rare 7
The multifidus plane block requires comparison with established techniques before routine clinical adoption, as acknowledged by the original case series authors 5
Regional blocks do not eliminate the need for multimodal analgesia - they are adjuncts to, not replacements for, comprehensive pain management 6
Ultrasound guidance is essential for both ESPB and SMFB to ensure proper needle placement and avoid complications 1, 5, 3, 4