Is Pain Blockage Safe? The Viewpoint Based on Nucleus Pulposus Cell Cytotoxicity
Authors: Kuh S. , Kang M. S. , Kim K. H. , Park J. Y. 
Published: May 2014

Introduction Local anesthetics combined with corticosteroids are commonly used for management of back pain in interventional spinal procedures. Several recent studies suggest cytotoxicity of bupivacaine, whereas others report protective and cytotoxic effects of corticosteroids on chondrocytes and intervertebral disc cells. Considering the frequent use of these agents in spinal interventions, it is meaningful to know how they affect intervertebral disc cells. This study was conducted to assess the effects of bupivacaine and triamcinolone, both alone and in combination, on viability of intervertebral disc cells in vitro. Materials and Methods Nucleus pulposus cells were isolated from human disc specimens from patients undergoing surgery due to disc herniation or degenerative disc disease. They were grown in three-dimensional alginate beads for 1 week to maintain their differentiated phenotypes and to allow for matrix formation before analysis. After 1 week of culture, the cells were exposed to bupivacaine (0.1, 0.25, 0.5, and 1%) or bupivacaine (0.1, 0.25, 0.5, and 1%) with 1 mg triamcinolone for 1, 3, or 6 hours. Cell viability was measured using trypan blue exclusion assay and flow cytometry. Live-cell/dead-cell fluorescent imaging was assessed using confocal microscopy. Results Trypan blue exclusion assays demonstrated dose- and time-dependent cytotoxic effects of bupivacaine on human nucleus pulposus cells. Similar but reduced cytotoxicity was observed after exposure to the combination of bupivacaine and 1 mg of triamcinolone. Flow cytometry showed a dose-dependent cytotoxic effect of bupivacaine on nucleus pulposus cells after 3 hours of exposure. The reduced cytotoxicity of bupivacaine combined with 1 mg triamcinolone was also confirmed in flow cytometry. Confocal images showed that the increase in dead cells correlated with the concentration of bupivacaine. Nevertheless, fewer cells died after exposure to several different concentrations of bupivacaine combined with 1 mg triamcinolone than did after exposure to bupivacaine alone. Conclusion The combination of bupivacaine and triamcinolone induced dose- and time-dependent cytotoxicity on human intervertebral disc cells in vitro, but the cytotoxicity was much weaker than that of bupivacaine alone. This study shows a potential protective influence of triamcinolone on intervertebral disc cells. Disclosure of Interest None declared References Hsiao CJ, Cherry DK, Beatty PC, Rechtsteiner EA. National Ambulatory Medical Care Survey: 2007 summary. Natl Health Stat Rep 2010; (27):1–32 Boswell MV, Trescot AM, Datta S, et al; American Society of Interventional Pain Physicians. Interventional techniques: evidence-based practice guidelines in the management of chronic spinal pain. Pain Physician 2007;10(1):7–111 Bogduk N. The lumbar disc and low back pain. Neurosurg Clin N Am 1991;2(4):791–806 Sehgal N, Fortin JD. Internal disc disruption and low back pain. Pain Physician 2000;3(2):143–157 Wetzel FT, LaRocca SH, Lowery GL, Aprill CN. The treatment of lumbar spinal pain syndromes diagnosed by discography. Lumbar arthrodesis. Spine 1994;19(7):792–800 Zucherman J, Hsu K, Picetti G III, White A, Wynne G, Taylor L. Clinical efficacy of spinal instrumentation in lumbar degenerative disc disease. Spine 1992;17(7):834–837 Choy DS, Ascher PW, Ranu HS, et al. Percutaneous laser disc decompression. A new therapeutic modality. Spine 1992;17(8):949–956 Onik G, Helms CA, Ginsburg L, Hoaglund FT, Morris J. Percutaneous lumbar diskectomy using a new aspiration probe. AJR Am J Roentgenol 1985;144(6):1137–1140 Wittenberg RH, Oppel S, Rubenthaler FA, Steffen R. Five-year results from chemonucleolysis with chymopapain or collagenase: a prospective randomized study. Spine 2001;26(17):1835–1841 Zhou Y, Abdi S. Diagnosis and minimally invasive treatment of lumbar discogenic pain—a review of the literature. Clin J Pain 2006;22(5):468–481