Neuraxial Anesthesia and Regional Nerve Blocks

What Is Being Utilized to Decrease Postoperative Spine Pain?

Regional anesthesia (RA), which includes both neuraxial anesthesia and regional nerve blocks, is an anesthetic technique employed in spine surgery to provide effective pain management and enhance patient outcomes. The literature has noted numerous advantages of RA over general anesthesia (GA), including reduced risk of respiratory complications, improved hemodynamic stability, reduced blood loss, decreased postoperative cognitive dysfunction, and reduced rates of venous thrombosis. Centers are employing Enhanced Recovery After Surgery protocols that streamline patient processes before, during, and after surgeries. These protocols generally include regional or neuraxial anesthesia to shorten the length of inpatient stays and facilitate early mobility and recovery while improving outcomes and patients’ overall experiences. In this article, we review the various neuraxial and regional nerve blocks currently employed to decrease postoperative pain, decrease perioperative anesthetic morbidity, and increase patient satisfaction for patients undergoing spine surgery.

Neuraxial Anesthesia

Neuraxial anesthesia, which includes both epidural anesthesia (EA) and spinal anesthesia (SA), involves the administration of local anesthetic and/or opioid into the epidural (EA) or subarachnoid space (SA). The injection of local anesthetic into the cerebrospinal fluid provides anesthesia, analgesia, as well as motor and sensory blockade. SA is typically administered as a single injection and must be given below the level of the conus medullaris to avoid injury to the spinal cord. EA can be given anywhere along the vertebral column and can be administered continuously through a catheter. This allows for the redosing of the anesthetic during and potentially after surgery, providing continuous pain relief.

Neuraxial anesthesia has several proposed advantages over GA. It has been associated with reduced intraoperative blood loss, lower mortality, fewer hypoxic episodes in the post-anesthesia care unit, and a decreased incidence of postoperative cognitive dysfunction.1-3 In the context of spine surgery, spinal anesthesia, when compared to GA, has been shown to lower postoperative pain scores,2,4,5 improve levels of patient satisfaction,4-6 and decrease postoperative nausea and vomiting (PONV).5,6 The literature has also shown that combined EA/GA with postoperative EA produced better pain control, less bleeding, and lower surgical stress response than GA with postoperative systemically administered narcotics.7

While neuraxial anesthesia has demonstrated some perioperative and postoperative benefits, as described above, it is still not widely accepted for spine procedures, and GA remains the most frequently used anesthetic technique for several reasons, such as a greater acceptance of GA by patients, as well as the fact that GA allows for more flexible management of the anesthetic duration during surgery. Many anesthesiologists prefer GA because it provides a more secure airway, especially before the patient is positioned in the prone position. If an epidural catheter is placed, it is generally in the operating field and can be an obstacle during surgery. Although a continuous infusion of anesthetic through a catheter can reduce postoperative pain scores, patients are often restricted to bed rest while the catheter is in place due to the motor blockade it induces below the level of anesthesia. These various factors have limited the use of neuraxial anesthesia for spine surgery.

Regional Nerve Block Modalities

Thoracic and Lumbar Regional Anesthetic Blocks

Erector Spinae Plane Block

The erector spinae plane block (ESPB) is a relatively newer regional anesthetic technique first described in 2016.8 It has garnered a lot of attention because of its ease of administration and relative safety.9

The ESPB is a fascial plane block that deposits local anesthetic in the fascial plane between the erector spinae muscle group and the transverse process of the vertebra. ESPBs consistently block the dorsal rami of the exiting spinal nerves that innervate the vertebra, skin, and dorsal musculature, thus providing somatic analgesia. There is extensive cranial and caudal spread through the paraspinal musculature through a single injection point, allowing for analgesic coverage of multiple vertebral levels with a single injection. A local anesthetic may also diffuse anteriorly to the ventral rami of the spinal nerves facilitating visceral analgesia.

An ESPB is commonly administered under ultrasound guidance. A needle is advanced toward the transverse process in a craniocaudal direction and confirmed by the linear spread of the injected anesthetic solution between the transverse process and the erector spinae muscle.10 Most studies have described a single shot of 10 to 30 mL of 0.25%-0.5% bupivacaine/ levobupivacaine or 0.25%-0.5% ropivacaine as the agent of choice.10 While an ESPB is commonly administered preoperatively by an anesthesia provider under ultrasound guidance, surgeons can administer this block under fluoroscopic guidance prior to making an incision or during the surgical procedure.

The ESPB is the most well-studied regional nerve block for patients undergoing spinal surgery. Multiple randomized controlled trials and meta-analyses have demonstrated that patients who receive an ESPB report reduced postoperative pain scores, lower postoperative opioid consumption, fewer episodes of PONV, reduced opioid-related adverse effects, and better patient satisfaction compared with control groups.5,10-13 Not only is the ESPB effective for posterior-only procedures, but the literature also shows that this block is associated with decreased postoperative inpatient opioid requirements and a shorter length of stay for patients undergoing circumferential fusions via anterior lumbar interbody fusion (ALIF) with concomitant posterior open procedures.14

While there is a theoretical concern that an ESPB may cause motor deficits due to potential anesthetic spread to the lumbar nerve roots, a clinically significant motor block is rarely, if ever, reported in the literature. Most studies emphasize the block's effectiveness in providing sensory analgesia without causing major motor impairment.

Thoracolumbar Interfascial Plane Block

The thoracolumbar interfascial plane (TLIP) block was first described in 201515 and targets the dorsal rami of the thoracolumbar nerves. This is a more superficial injection compared to the ESPB and involves injecting anesthetic between the multifidus and longissimus muscles, aiming to block the branches of the dorsal rami as they traverse this intermuscular plane. The modified TLIP (mTLIP) block, which is performed laterally to the standard TLIP block, is also described. In this technique, a needle is advanced in a mediolateral orientation, and anesthetic is administered between the longissimus and iliocostal muscles.

The TLIP block has gained attention as an effective alternative to the ESPB due to several purported advantages. First, some believe that the TLIP block targets a more defined and reliable plane. Because the primary site of injection and local anesthetic deposition in the TLIP block is somewhat farther from the lumbar nerve roots and plexus compared to the ESPB, there is a theoretical lower risk of motor blockade and interference with intraoperative neuromonitoring. Additionally, by focusing on the interfascial plane where the lumbar nerve roots exit, the TLIP block may provide superior analgesia.

While the available literature on the TLIP block is less abundant than that on ESPBs, studies demonstrate that TLIP blocks reduce pain scores at rest and with movement for up to 24 hours, decrease total analgesic consumption, and lower the incidence of PONV.16,17 Wang et al conducted a randomized controlled trial (RCT) comparing ESPB, TLIP, and a control group (no block) for patients undergoing 2- to 3-level lumbar fusion surgeries. They found that patients who underwent an ESPB had better analgesic effects, lower pain scores in static states, and a lower frequency of patient-controlled analgesia requirements and opioid analgesic consumption compared with those who underwent the TLIP block.18 A second RCT by Cifti et al randomized 90 patients undergoing lumbar microdiscectomy into three groups: ESPB, mTLIP, and control. They found that postoperative opioid consumption was significantly lower in both the ESPB and mTLIP groups compared to the control group. However, there was no significant difference in intra- and postoperative opioid consumption between the ESPB and mTLIP groups.19 The authors concluded that there is no superiority between ESPB and mTLIP but that either block is superior to not receiving one.19 Further high-quality randomized studies are needed to compare the results of these blocks.

Transversus Abdominis Plane Block

The transversus abdominis plane (TAP) block is a regional anesthetic technique first described in 2001 as a method of providing analgesia for abdominal surgeries.20 The TAP block is now being used as part of multimodal analgesia protocols for patients undergoing anterior and lateral lumbar fusions.21,22 The TAP block utilizes ultrasonography to administer a single injection of local anesthetic in the potential space between the transversus abdominis and internal oblique muscles, which allows for effective analgesia to the anterior and lateral abdominal wall.

The literature reports mixed findings regarding whether a TAP block improves outcomes and reduces postoperative opioid consumption. Multiple retrospective studies have demonstrated significant benefits of a TAP block after ALIF, including significantly shorter length of stay, less PONV, and lower opioid consumption.22,23 In contrast, Coquet et al conducted an RCT in which patients were randomized to receive a TAP block performed at the end of surgery with either ropivacaine or a placebo (isotonic saline). They found that the TAP block, regardless of whether ropivacaine or placebo was used, provided similar postoperative analgesia between the groups.24 Larger RCTs are essential to establish the safety and efficacy of TAP blocks for anterior and lateral lumbar interbody fusions.

Cervical Regional Anesthetic Blocks

Regional anesthetic blocks are less commonly employed for cervical spine surgery than for thoracic and lumbar spine surgery. Both the multifidus cervicis plane (MCP) and inter-semispinal plane (ISP) blocks have been described to help decrease postoperative pain and opioid requirements for patients undergoing posterior cervical spine surgery.25,26 The anesthetic agent targets the branches of the dorsal rami of cervical nerves traversing in the intermuscular plane.

The MCP block was first described as a case report of cervical laminoplasty perioperative analgesia and exploited the fascial plane between multifidus cervices and semi-spinalis cervices muscles at the level of the C5 spinous process.25 The ISP block is more superficial, and local anesthetic is deposited between the semispinalis cervicis and semispinalis capitis muscles. In one study, patients undergoing posterior cervical spine surgery were randomized to receive either GA alone (the control group) or bilateral ultrasound-guided ISP blocks at the C5 level with 20 mL of bupivacaine 0.25% in each side with GA (the ISP group). The authors found that after 30 minutes, 6 hours, 8 hours, and 12 hours postoperatively, the visual analog scale (VAS) scores of patients in the ISP group were considerably lower than those of patients in the control group.27 While this study shows promising results, further high-quality studies are necessary to prove their efficacy and make these blocks more mainstream.

The cervical plexus block (CPB) is a regional anesthetic technique that can be used in anterior cervical spine surgery as a part of the multimodal treatment plan to mitigate postoperative pain. The cervical plexus is formed by the anterior rami of C1-4 and lies deep to the prevertebral fascia on the scalenus medius muscle. To perform a CPB, an ultrasound probe is centered over the posterior edge of the sternocleidomastoid. The cervical plexus is identified through the interscalene groove, and about 15 mL of anesthetic solution is injected, anesthetizing 4 superficial branches of the cervical plexus.28 In a single-center RCT, 46 patients were randomized to either receive a superficial cervical plexus block or no block. The authors found that while early quality of recovery improved, measured by a 40-item quality of recovery questionnaire, both groups had similar opioid consumption and discharge times.29

Conclusion

Neuraxial anesthesia and regional nerve blocks represent valuable techniques in the management of postoperative pain for patients undergoing spine surgery. Techniques such as the ESPB and TLIP have demonstrated efficacy in reducing pain scores and opioid consumption and enhancing patient satisfaction. However, the effectiveness of these blocks can vary depending on the technique, surgical procedure, and patient factors. While some blocks, such as the ESPB, show promise for reducing pain and improving recovery outcomes, other regional blocks require further high-quality research to establish their full potential. As the field of regional anesthesia continues to evolve, it is essential to refine these techniques through continued investigation, allowing clinicians to tailor pain management strategies to the individual needs of spine surgery patients. Ultimately, the integration of regional anesthesia into multimodal analgesia protocols holds significant potential for improving outcomes, accelerating recovery, and enhancing the overall surgical experience for patients undergoing spine procedures.

References

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14. Colón LF, Miles D, Scheinberg M, Wilson A, Shepherd B, Miller J. Erector spinae plane blocks for circumferential lumbar spinal fusion: retrospective cohort study. Int J Spine Surg. 2023;17(5):715-720.

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18. Wang L, Wu Y, Dou L, Chen K, Liu Y, Li Y. Comparison of two ultrasound-guided plane blocks for pain and postoperative opioid requirement in lumbar spine fusion surgery: a prospective, randomized, and controlled clinical trial. Pain Ther. 2021;10(2):1331-1341.

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21. Colón LF, White CC, Miles DT, et al. Transversus abdominis plane block as part of a multimodal analgesic regimen in patients undergoing anterior lumbar interbody fusion: a retrospective cohort study. Int J Spine Surg. 2023;17(3):426-433.

22. Reisener MJ, Hughes AP, Okano I, et al. The association of transversus abdominis plane block with length of stay, pain and opioid consumption after anterior or lateral lumbar fusion: a retrospective study. Eur Spine J. 2021;30(12):3738-3745.

23. Esmende SM, Solomito MJ, Eisler, et al. Utility of the transversus abdominis plane and rectus sheath blocks in patients undergoing anterior lumbar interbody fusions. Spine J. 2022;22(10):1660-1665.

24. Coquet A, Sion A, Bourgoin A, Ropars M, Beloeil H. Transversus abdominis plane block for anterior lumbar interbody fusion: a randomized controlled trial. Spine J. 2023;23(8):1137-1143.

25. Ohgoshi Y, Izawa H, Kori S, Matsukawa M. Multifidus cervicis plane block is effective for cervical spine surgery. Can J Anaesth. 2017;64(3):329-330.

26. Ohgoshi Y, Nishizakura R, Takahashi Y, et al. Novel ultrasound-guided inter-semispinal plane block: a comparative pilot study in healthy volunteers. J Anesth. 2018;32(1):143-146.

27. Mostafa SF, Abu Elyazed MM, Eid GM, Belal AM. Inter-semispinal plane (ISP) block for postoperative analgesia following cervical spine surgery: a prospective randomized controlled trial. J Clin Anesth. 2022;83:10974.

28. Mulcahy MJ, Elalingam T, Jang K, D’Souza M, Tait M. Bilateral cervical plexus block for anterior cervical spine surgery: study protocol for a randomised placebo-controlled trial. Trials . 2021;22(1):424.

29. Mariappan R, Mehta J, Massicotte E, et al. Effect of superficial cervical plexus block on postoperative quality of recovery after anterior cervical discectomy and fusion: a randomized controlled trial. Can J Anaesth. 2015;62(8):883-890.

Contributors:

Jonathan Markowitz, MD

Gregory Lopez, MD

From the Department of Orthopaedic Surgery at Rush University Medical Center in Chicago, Illinois.