Paravertebral block is an anesthetic technique used for both intraoperative and postoperative analgesia. Though the technique was pioneered in the early 20th century, it did not gain prominence until the 1970s, when physicians Eason and Wyatt published a case series demonstrating their successful use of the paravertebral block to deliver analgesia.1
Paravertebral block is achieved by injecting a local anesthetic laterally to the intervertebral foramen, proximal to the spinal nerves, in order to achieve segmented and unilateral nerve blockade.
A number of different techniques can be used to achieve thoracic paravertebral block:2
- Loss-of-resistance technique: After numbing the dermal layer at the chosen injection site, the longer block needle is inserted at a 90° angle into the transverse process, pars intervertebralis, or articular column. Loss of resistance indicates successful insertion into the thoracic paravertebral space.
- Predetermined distance technique: Though similar to the loss-of-resistance technique, the predetermined distance technique first involves a sonographic measurement of the distance to the transverse process.3 This methodology reduces risk of pleural or pulmonary puncture.
- Catheter technique: Long-term thoracic paravertebral block may require the insertion of a catheter into the thoracic paravertebral space. This method is most complex and, for this reason, is exclusively performed during thoracotomies or using ultrasound under direct vision.4
There are two primary forms of paravertebral block, differing by location of injection: thoracic and lumbar. Thoracic paravertebral block is typically used for unilateral surgical procedures on the chest or abdomen, or to treat acute/chronic pain in these areas. When performing a thoracic paravertebral block, the physician injects local anesthetic directly into the thoracic paravertebral space, which contains adipose tissue as well as a number of bundled spinal nerves.1 Given the extensive vascularization in the area of injection, the local anesthesia is absorbed and analgesia takes effect rapidly. In order to prevent a dangerous spike in systemic anesthetic concentration as well as to prolong analgesia, epinephrine is often added to the injected solution.5
Lumbar paravertebral block, on the other hand, is a bit more complicated. Unlike the thoracic paravertebral space, the lumbar paravertebral space is surrounded primarily by muscle, not adipose tissue.6 For this reason, the needle must be inserted in a small space within the psoas major muscle in order to reach the lumbar spinal nerve root. It may therefore be necessary to perform a lumbar paravertebral block under direct vision, such as during open surgery or using ultrasound. Despite this key difference, lumbar paravertebral block uses similar techniques to thoracic paravertebral block. Lumbar paravertebral block is often done in conjunction with thoracic paravertebral block for major surgery, or singularly used to relieve severe hip/inguinal pain.7,8
Both types of paravertebral block require long-lasting local anesthetics, such as bupivacaine, ropivacaine, or levobupivacaine. Multiple injections can be made along the spine for a larger area of analgesia or one injection of a large amount of anesthesia. Contraindications include infection, allergy to anesthetic agents, or blockage of the paravertebral space.9
Given that paravertebral block is a relatively straightforward anesthetic procedure, complication rates are low. A comprehensive study conducted by Lönnqvist et al. reported hypotension and vascular puncture as the two most common complications, at a frequency of 4.6 and 3.8 percent, respectively.10
References
1 Eason, M. J., & Wyatt, R. (1979). Paravertebral thoracic block-a reappraisal. Anaesthesia, 34(7), 638–642. https://doi.org/10.1111/j.1365-2044.1979.tb06363.x
2 Batra, R. K., Krishnan, K., & Agarwal, A. (2011). Paravertebral block. Journal of anaesthesiology, clinical pharmacology, 27(1), 5–11.
3 Pusch, F., Wildling, E., Klimscha, W., & Weinstabl, C. (2000). Sonographic measurement of needle insertion depth in paravertebral blocks in women. British journal of anaesthesia, 85(6), 841–843. https://doi.org/10.1093/bja/85.6.841
4 Luyet, C., Eichenberger, U., Greif, R., Vogt, A., Szücs Farkas, Z., & Moriggl, B. (2009). Ultrasound-guided paravertebral puncture and placement of catheters in human cadavers: an imaging study. British journal of anaesthesia, 102(4), 534–539. https://doi.org/10.1093/bja/aep015
5 Karmakar M. K. (2001). Thoracic paravertebral block. Anesthesiology, 95(3), 771–780. https://doi.org/10.1097/00000542-200109000-00033
6 Nojiri, H., Miyagawa, K., Yamaguchi, H., Koike, M., Iwase, Y., Okuda, T., & Kaneko, K. (2019). Intraoperative ultrasound visualization of paravertebral anatomy in the retroperitoneal space during lateral lumbar spine surgery. Journal of neurosurgery. Spine, 31(3), 334–337. https://doi.org/10.3171/2019.3.SPINE181210
7 Santonastaso, D. P., De Chiara, A., Kraus, E., Bagaphou, T. C., Tognù, A., & Agnoletti, V. (2019). Ultrasound guided erector spinae plane block: an alternative technique for providing analgesia after total hip arthroplasty surgery?. Minerva anestesiologica, 85(7), 801–802. https://doi.org/10.23736/S0375-9393.19.13459-1
8 Klein, S. M., Pietrobon, R., Nielsen, K. C., Steele, S. M., Warner, D. S., Moylan, J. A., Eubanks, W. S., & Greengrass, R. A. (2002). Paravertebral somatic nerve block compared with peripheral nerve blocks for outpatient inguinal herniorrhaphy. Regional anesthesia and pain medicine, 27(5), 476–480. https://doi.org/10.1053/rapm.2002.35147
9 Tighe, S. Q. M., Greene, M. D., & Rajadurai, N. (2010, August 17). Paravertebral Block. OUP Academic. Retrieved from https://academic.oup.com/bjaed/article/10/5/133/274956
10 Lönnqvist, P. A., MacKenzie, J., Soni, A. K., & Conacher, I. D. (1995). Paravertebral blockade. Failure rate and complications. Anaesthesia, 50(9), 813–815. https://doi.org/10.1111/j.1365-2044.1995.tb06148.x