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Pain Reduction and Repeat Injections After Transforaminal Epidural Injection With Particulate Versus Nonparticulate Steroid for the Treatment of Chronic Painful Lumbosacral Radiculopathy
1 2 3 4 5 PM R XXX (2016) 1-7 www.pmrjournal.org 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21Q5 22 23 24 25 26 27 28 29 30 31 32 Abstract 33 34 35 Background: The corticosteroid choice for a lumbar transforaminal epidural steroid injection (TFESI) remains controversial. 36 Whether to utilize particulate or nonparticulate steroid preparations for these injections remains an unanswered question in the 37 38 literature. 39 Objective: To determine if a particulate or nonparticulate steroid is more effective in the treatment of electromyography (EMG)40 confirmed lumbosacral radiculopathy. 41 Design: Multicenter retrospective cohort study. 42 43 Setting: Two tertiary academic spine centers. 44 Patients: Consecutive patients, aged 18 years or older, with EMG-confirmed lumbosacral radiculopathy. 45 Interventions: TFESI with a particulate or nonparticulate steroid to treat radicular pain within 6 months of EMG. 46 47 Main Outcome Measures: The primary outcome was the proportion of patients with 50% pain reduction on the numerical rating 48 scale after TFESI. Secondary outcomes included mean numerical rating scale score reduction and number of repeat TFESIs. Short49 term (<30 days) and intermediate (30 days) outcomes were compared between patients who received a TFESI with a particulate 50 51 versus nonparticulate steroid. 52 Results: Seventy-eight patients, with an age standard deviation of 56 16 years and a mean symptom duration of 49 71 53 months, were included. Forty-one patients (52%) received dexamethasone, 23 (30%) received triamcinolone, and 14 (18%) 54 received betamethasone. There was no statistically significant difference in the proportion of patients who reported 50% pain 55 56 reduction between the particulate and nonparticulate groups at short-term follow-up (35%; 95% confidence interval [CI], 21-51 57 versus 28%; 95% CI, 13-43) or at intermediate follow-up (40%; 95% CI, 21-59 versus 39%; 95% CI, 19-59). There was no difference in 58 the mean number of injections administered between groups at intermediate follow-up (P ¼ .26). 59 60 Conclusions: This study demonstrates no significant differences in pain reduction or the number of repeat injections with 61 particulate compared with nonparticulate transforaminal epidural steroid injection in patients with EMG-confirmed painful 62 lumbosacral radiculopathy. These findings suggest a new population for whom nonparticulate steroid appears to be an appropriate 63 first-line therapy, although confirmation with a randomized study is needed. 64 65 66 67 68 69 70 Introduction preparations for these injections remains an unan71 swered question in the literature [1]. Nonparticulate 72 73 The corticosteroid choice for lumbar transforaminal steroids are believed to elicit a shorter duration of 74 epidural steroid injection (TFESI) remains controversial. analgesic effect compared with insoluble, particulate 75 76 Whether to utilize particulate or nonparticulate steroid steroids [2]. Particulate steroids have been implicated 77 78 79 1934-1482/$ - see front matter ª 2016 by the American Academy of Physical Medicine and Rehabilitation 80 http://dx.doi.org/10.1016/j.pmrj.2016.03.011
Original Research
Pain Reduction and Repeat Injections After Transforaminal Epidural Injection With Particulate Versus Nonparticulate Steroid for the Treatment of Chronic Painful Lumbosacral Radiculopathy
Zachary McCormick, MD, Daniel Cushman, MD, Benjamin Marshall, DO, Mary Caldwell, DO, Jaymin Patel, MD, Leda Ghannad, MD, Christine Eng, MD, Steven Makovitch, DO, Ashwin Babu, MD, Samuel K. Chu, MD, Christina Marciniak, MD, David R. Walega, MD, Joel Press, MD, Christopher Plastaras, MD, David J. Kennedy, MD
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Steroids for EMG-Confirmed Painful Radiculopathy
in all known cases of epidural steroid injectionerelated spinal cord infarctions [3-10]. The larger size or aggregation of particulate steroids [2,11] likely obstructs arteriolar blood flow to the spinal cord if these steroids are inadvertently injected into radicular arteries during TFESI [12-15]. Further, several studies have demonstrated that dexamethasone, the only nonparticulate steroid available for clinical use, is not inferior to particulate corticosteroids with regard to pain reduction and functional improvement, therefore justifying its use as a first-line medication for TFESI in the treatment of lumbosacral radicular pain [16-18]. Prior studies have directly compared the efficacy of dexamethasone and various particulate corticosteroids including triamcinolone, betamethasone, and methylprednisolone with varying results for lumbosacral radicular pain [16-20]. Four studies suggested minimal to no difference in clinical outcomes when using a particulate versus nonparticulate steroid during TFESI [16-18] and interlaminar epidural steroid injection [19], whereas one study suggested superior outcomes associated with the use of a particulate steroid compared with a nonparticulate steroid during repeat TFESIs in which the first injection was not effective [20]. Radiating leg pain has a wide differential diagnosis, and although injections are often administered for radicular pain, no study to date has compared the efficacy of particulate and nonparticulate steroids for the treatment of radicular pain with needle electromyography (EMG)-confirmed radiculopathy. The aim of the present study was to determine if TFESI with particulate or nonparticulate steroid is associated with greater reduction of pain or a reduction in the number of repeat injections in the treatment of the specific patient population with needle EMG-confirmed lumbosacral radiculopathy. Methods This retrospective cohort study was approved by respective Institutional Review Boards at 2 interventional spine practices in urban tertiary academic medical centers between May 2007 and December 2013. The data used in this study were obtained by retrospective query of the electronic medical record at both institutions. Consecutive patients aged 18 years or older who demonstrated EMG-confirmed painful lumbosacral radiculopathy and also underwent a TFESI within 6 months of the EMG for treatment of pain were included, consistent with criteria used in a prior investigation [21]. EMGs were obtained at the discretion of the treating physician and were not considered routine care. EMG-confirmed radiculopathy was defined as more than one muscle abnormality in a discrete myotome but different nerve distributions on at least a 6-muscle screen including paraspinal muscles or at least an 8-muscle screen without paraspinal muscles, with
changes consistent with denervation including positive waves, fibrillation potentials, large amplitude and duration motor units, and polyphasic motor units of significant amplitude (“neuropathic”) to be distinguished from “myopathic” motor units [22]. Pain was considered radicular in character when history was consistent with lancinating pain radiating to a limb in a distribution corresponding to the involved nerve root according to EMG testing. The diagnosis of radicular pain was also supported by concordant disease on magnetic resonance imaging (MRI) of the lumbosacral spine. Patients were excluded from the analysis if an epidural steroid injection (ESI) was performed more than 6 months after the EMG was performed or if the patient had an ESI in the 6 months prior to the EMG. Patients with a history of prior spinal surgery were excluded, because this intervention can confound EMG findings used in the electrodiagnosis of radiculopathy, particularly in the paraspinal muscles [23,24]. In this study, the following data were analyzed: age, gender, body mass index, duration of radicular symptoms, alcohol use, symptom cause related to a motor vehicle accident, disability status, reason for obtaining an EMG, MRI diagnosis concordant with the affected spinal nerve root determined by EMG, numerical rating scale (NRS) pain scores, steroid type used during TFESI, repeat TFESI treatments, and time to follow-up. At both institutions, standard clinical protocol included a patient return visit 2-4 weeks after the injection and a second follow-up visit 8-12 weeks after the injection to reassess symptoms and physical functioning. Each injection was ordered and performed by a physician who was board certified in Physical Medicine and Rehabilitation and also had additional subspecialty board certification in either Pain Medicine or Sports Medicine. Nine different attending physicians who had between 5 and 14 years of clinical experience of interventional spine care performed these injections. In all patients, single-level, unilateral TFESIs were performed using a standard, fluoroscopy-guided subpedicular technique [25]. The patient was placed prone and the skin was prepped using sterile technique. The fluoroscope was positioned to obtain an oblique view of the subpedicular space. The skin and soft tissue were anesthetized using 1% lidocaine (preservative free). A sterile 22-gauge 3.5-, 5-, or 7-inch spinal needle was then advanced to the superior aspect of the neural foramen above the exiting spinal nerve. Anteriorposterior, oblique, and lateral fluoroscopic views were obtained to confirm accurate needle placement. Subsequently, 1-2 mL of contrast dye (Isovue 300, Bracco Diagnostics Inc, Monroe, NJ) was injected through microbore tubing with use of live fluoroscopy. If intravenous dye uptake occurred, the needle was repositioned until intravenous uptake was absent and an epidural flow pattern was evident. If intra-arterial, intrathecal, or intradiskal flow was identified, the
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procedure was aborted. A total of 1.5-2 mL of corticosteroid (15 mg dexamethasone sodium phosphate [10 mg/mL], 12 mg betamethasone acetate [6 mg/mL], or 80 mg triamcinolone acetonide [40 mg/mL]; equipotent doses [26]) was injected. The type of steroid used varied over time, with betamethasone or triamcinolone (particulate steroids) used almost exclusively during the earlier study dates, with a gradual transition around the year 2010 on a clinician-to-clinician basis to use of dexamethasone (a nonparticulate steroid) that was used almost exclusively because of safety concerns related to the use of particulate steroids during TFESI and the possibility of spinal cord infarction. Repeat injections were never performed routinely; rather, this decision was made at the discretion of the treating attending physician. Data Analysis Proportions for categorical variables in addition to means and standard deviations (SDs) for continuous variables were calculated. Follow-up was categorized as <30 days (short term) and 30 days (intermediate). The primary outcome measure for this study was the proportion of patients who experienced 50% reduction of pain on the NRS after TFESI at short-term follow-up. Secondary outcomes included the mean change in NRS and the mean number TFESIs performed, as well as the proportion of patients who received a repeat TFESI. The particulate steroid group was compared with the nonparticulate steroid group with regard to these outcome measures. Primary analysis excluded patients who were lost to follow-up. Additional “best” and “worst” case scenario analyses were performed to account for the possible range of “true” pain outcomes given loss to follow-up. The best-case scenario analysis assumes that all patients lost to follow-up experienced 50% improvement in NRS pain score. The worst-case scenario analysis assumes that all patients lost to follow-up experienced <50% improvement in NRS pain score. Groups were stratified by demographic and clinical characteristics to identify confounding group differences. Statistical Analysis Data were checked for normal distributions using summary statistics and graphical displays. The c2 statistic was used to compare categorical variables, and analysis of variance was used to compare numerical variables. Data were analyzed using PSPP version 0.8.3 (Gnu Project, Boston, MA). The level of significance was set at .05 for all statistical tests. Two-sided testing was used for all hypothesis testing.
3
Results A total of 78 consecutive patients with EMGconfirmed lumbosacral radiculopathy received a TFESI for painful radiculopathy during the study time frame. Eight patients (10%) were lost to follow-up at short-term follow-up (3 from the particulate group and 5 from the nonparticulate steroid group). An additional 22 patients (28%) were lost to follow-up at intermediate follow-up (12 from the particulate group and 18 from the nonparticulate steroid group). Demographic, clinical, and procedural characteristics of the study population are shown in Table 1. The mean age SD was 56 16 years, and the mean duration of symptoms prior to ESI was 49 71 months. Forty-one patients (52%) received a nonparticulate steroid (dexamethasone) and 37 patients (48%) received a particulate steroid (triamcinolone, n ¼ 23 [30%]; betamethasone, n ¼ 14 [18%]). Seventy patients (90%) received an EMG to clarify the diagnosis. The mean SD time to short-term follow-up after the injection was 18 6 days, and the time to intermediate follow-up was 86 55 days. Baseline demographic, clinical, and procedural characteristics of patients who received a particulate steroid were compared with those of patients who received a nonparticulate steroid (Table 1). The particulate group had a shorter duration of symptoms before the intervention compared with the nonparticulate group (32 versus 79 months, P ¼ .03). More patients who received a particulate steroid compared with a nonparticulate steroid had an MRI diagnosis of disk herniation or a disk bulge contacting a spinal nerve root that was concordant with the level of radiculopathy defined by EMG (P ¼ .03). Both the particulate and nonparticulate groups had similar proportions of patients who required repeat TFESI (27% versus 39%, P > .05). No statistically significant difference was found in the proportion of patients who reported 50% pain reduction on the NRS between the particulate and nonparticulate groups at short-term follow-up (35%; 95% confidence interval [CI], 19-51 versus 28%; 95% CI, 1343, respectively) or at intermediate follow-up (40%; 95% CI, 21-59 versus 39%; 95% CI, 19-59, respectively; Table 2). The best- and worst-case scenario analyses for pain outcomes also demonstrated no significant differences between these groups (Table 3). No difference was found in the mean number of injections administered between groups by the time of intermediate follow-up (P ¼ .26). In comparing demographic, procedural, and outcome data between the 2 centers, nonparticulate steroids were used more frequently than particulate steroids (P < .001). No other significant differences were found between the 2 centers (P > .05 in all other comparisons). These data included age, gender, BMI, duration of symptoms, alcohol consumption, disability, pain related
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Steroids for EMG-Confirmed Painful Radiculopathy
561 Table 1 562 Characteristics of patients with needle electromyography-proven painful radiculopathy, stratified by those who received transforaminal epidural Q3 563 particulate versus nonparticulate steroid injection
Variable Age, y Gender, % female BMI, kg/m2 Duration of symptoms, mo >3 drinks/day Tobacco use Symptoms associated with MVC Receiving disability benefits Reason for EMG Clarify diagnosis of radiculopathy versus other disease Clarify nerve root level MRI diagnosis concordant with affected spinal nerve root determined by EMG* Disk herniation or bulge contacting nerve root Central canal stenosis Neural foraminal stenosis Only disk herniation or bulge contacting nerve root Only central stenosis Only foraminal stenosis Only central and/or foraminal stenosis Mean time to short-term follow-up (<30 days), days Mean time to intermediate follow up (30 days), days NRS prior to injection
All Patients n ¼ 78 Mean (SD) or n (%)
Particulate Steroid Group n ¼ 37 Mean (SD) or n (%)
Nonparticulate Steroid Group n ¼ 41 Mean (SD) or n (%)
56 38 30 49 1 9 4 3
58 19 30 32 1 3 1 1
56 20 30 71 0 6 3 2
(16) (49%) (7) (71) (3%) (14%) (6%) (5%)
(16) (51%) (5) (51) (3%) (10%) (3%) (3%)
(16) (49%) (8) (86) (0%) (18%) (9%) (6%)
.54 .63 .92 .03 .64 .41 .26 .65 .55
70 (90%) 8 (10%)
34 (92%) 3 (8%)
36 (88%) 5 (12%)
49 22 22 32 4 4 14 18 86 6
24 7 6 19 2 1 4 17 88 6
25 15 16 13 2 3 10 18 84 6
(70%) (31%) (31%) (46%) (6%) (6%) (20%) (6) (55) (3)
(77%) (23%) (19%) (61%) (6%) (3%) (13%) (7) (64) (3)
P Value
(62%) (38%) (52%) (33%) (5%) (8%) (26%) (5) (44) (2)
.30 .20 .07 .03 1.0 1.0 .24 .37 .80 .96
SD ¼ standard deviation; BMI ¼ body mass index; MVC ¼ motor vehicle collision; EMG ¼ electromyography; MRI ¼ magnetic resonance imaging; NRS ¼ numerical rating scale. * MRI diagnosis not available in 8 patients; 6 missing from the particulate group and 2 from the nonparticulate group.
to a motor vehicle accident, baseline NRS pain score, decrease in mean decrease in pain scores at short- and long-term follow-up, and proportion of responders (50% reduction in NRS pain score). No catastrophic adverse events of TFESI occurred in this study (ie, vascular or neurologic compromise).
Discussion This investigation is the first to compare clinical outcomes of the use of epidural particulate and nonparticulate steroids for the treatment of radicular pain in patients with proven objective nerve root disease.
Table 2 Particulate versus nonparticulate steroid group comparison of numerical rating scale pain score improvement and repeat transforaminal epidural steroid injections in patients with needle electromyography-proven painful radiculopathy Outcome
Data Available, n
Short-term follow-up* 50% NRS improvement <50% NRS improvement Intermediate follow-up† 50% NRS improvement <50% NRS improvement Short-term follow-up* Mean NRS improvement Intermediate follow-up* Mean NRS improvement Mean No. of repeated TFESIs
70
Particulate Steroid Group Mean (SD) or n (%; 95% CI)
Nonparticulate Steroid Group Mean (SD) or n (%; 95% CI)
P Value
12 (35; 19-51) 22 (65; 49-81)
10 (28; 13-43) 26 (72; 57-87)
.50
10 (40; 21-59) 15 (60; 41-79)
9 (39; 19-59) 14 (61; 41-81)
.95
48
70 48
3.5 (4.2) 2.8 (5.1)
2.1 (7.5) 3.4 (4.6)
.33 .65
48
0.4 (0.7)
0.6 (0.9)
.15
SD ¼ standard deviation; CI ¼ confidence interval; NRS ¼ numerical rating scale; TFESI ¼ transforaminal epidural steroid injection. * Short-term follow-up corresponds to <30 days. † Intermediate follow-up corresponds to 30 days. FLA 5.4.0 DTD PMRJ1687_proof 11 April 2016 1:13 pm ce
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5
721 722 723 Particulate Steroid Group Nonparticulate Steroid Group 724 725 Outcome n (%; 95% CI) n (%; 95% CI) P Value 726 Best-case scenario 727 † 728 Short-term follow-up .72 729 50% NRS improvement 15 (41; 25-57) 15 (37; 22-52) 730 <50% NRS improvement 22 (59; 43-75) 26 (63; 48-78) 731 ‡ Intermediate follow-up .56 732 50% NRS improvement 22 (59; 43-75) 27 (66; 52-81) 733 <50% NRS improvement 15 (41; 25-57) 14 (34; 20-49) 734 735 Worst-case scenario 736 Short-term follow-up† .43 737 50% NRS improvement 12 (32; 17-47) 10 (24; 11-37) 738 <50% NRS improvement 25 (68; 53-83) 31 (76; 63-89) 739 Intermediate follow-up‡ .60 740 50% NRS improvement 10 (27; 13-41) 9 (22; 9-35) 741 742 <50% NRS improvement 27 (73; 59-87) 32 (78; 65-91) 743 CI ¼ confidence interval; NRS ¼ numerical rating scale. 744 * The best-case scenario assumes that all patients lost to follow-up experienced 50% improvement in NRS pain score. The worst-case scenario Q4 745 746 assumes that all patients lost to follow-up experienced <50% improvement in NRS pain score. † 747 Short-term follow-up corresponds to <30 days. 748 ‡ Intermediate follow-up corresponds to 30 days. 749 750 751 752 included only patients with acute lumbar disk herniaThis study suggests that there is no significant disad753 tions, whereas the present data reflect persons with vantage of TFESI with the nonparticulate steroid, 754 755 chronic symptoms due to any structural cause. dexamethasone, compared with 2 particulate steroids, 756 It is interesting and unexpected that although isotriamcinolone and betamethasone, for reduction of pain 757 lated disk herniations or disk bulges contacting a spinal or number of injections in patients with EMG-confirmed 758 759 nerve root (with no concomitant foraminal or central lumbosacral radiculopathy. 760 stenosis) were the more prevalent identified structural These results build on the emerging literature 761 762 cause of EMG-confirmed radiculopathy in the particucomparing the effectiveness of nonparticulate versus 763 late group than in the nonparticulate group (P ¼ .03), particulate steroids in epidural steroid injections for 764 765 the particulate group did not experience a greater radicular pain [16-20]. Evidence suggests that no sig766 likelihood of clinically significant pain reduction nificant difference exists in clinical outcomes when 767 compared with the nonparticulate group. This finding is nonparticulate or particulate steroids are used for TFESI 768 769 striking given that TFESI for lumbosacral disk herniation in patients with radicular pain. In one study, 770 has generally been demonstrated to be more effective El-Yahchouchi et al [16] compared dexamethasone with 771 772 than TFESI for lumbar spinal stenosis [27-30]. This triamcinolone or betamethasone in a large retrospective 773 finding may further speak to the justified use of a nonstudy (n ¼ 2634) of patients with lumbosacral radicular 774 particulate steroid as a first-line treatment in this pain, and no significant difference in pain or functional 775 776 population. outcomes was demonstrated at 2 months. Kennedy et al 777 [17] compared dexamethasone with triamcinolone for 778 779 Limitations the treatment of lumbosacral radicular pain due to an 780 acute disk herniation in a randomized, double-blind trial 781 This unique study examined a patient population with of 78 patients and found no significant between-group 782 783 chronic radicular pain and radiculopathy confirmed by differences in pain reduction (NRS), functional 784 EMG, with the primary results generally consistent with improvement (Oswestry Disability Index), or rates of 785 786 the known literature on this topic. However, this study surgical intervention. 787 has several limitations. First, because EMGs were not Although the present findings are generally consistent 788 789 the standard of care for all patients with radicular pain, with prior studies, in the present study there was no 790 only a subset of patients actually underwent this testing statistically significant difference in the need for repeat 791 at the discretion of the treating physician. The typical TFESIs, in contrast to the study by Kennedy et al [17], in 792 793 indication for an EMG was to confirm the diagnosis in the which it was found that patients treated with dexa794 setting of an unclear clinical picture when symptoms methasone required a greater mean number of repeat 795 796 and physical examination findings did not clearly injections to achieve a successful clinical outcome 797 correlate with imaging findings. Therefore, the patients compared with patients treated with particulate ste798 undergoing this additional testing may not be the same roids. This difference may be related to the differences 799 800 as those with clear single-level radicular pain and in our study population, because Kennedy et al [17]
Table 3 Best and worst-case scenario pain outcomes (n ¼ 78)
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6 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880
Steroids for EMG-Confirmed Painful Radiculopathy
concordant MRI imaging. Also, while limiting this study to the unique cohort of only patients who had EMG positive radiculopathy, the radiculopathy identified could be due to different diseases such as a disk herniation or spinal stenosis. These diseases have different natural histories and could possibly have different responses to treatment. However, given that the goal of the study was to compare the pain outcomes of the 2 groups, this heterogeneity should have been equally distributed between groups as evidenced by the fact that the only variable that was significantly different between the cohorts was a longer duration of symptoms prior to intervention in the nonparticulate steroid group. The type of steroid used changed over time, with betamethasone or triamcinolone used almost exclusively during the earlier study dates and a gradual transition around 2010 on a clinician-to-clinician basis to dexamethasone that was used almost exclusively because of safety concerns related to the use of particular steroids during TFESI and the possibility of spinal cord infarction. Randomized study in the future is needed to confirm the present results. There was no standardized protocol for repeating TFESIs. Rather, the decision to repeat an injection was made at the discretion of the treating attending physician on a case-by-case basis that never included a “reflex” or “automatic” repeat TFESI. Although this protocol introduces an element of variability, it is representative of realistic clinical practice, and it improves the generalizability of the present findings, because multiple attending physicians at 2 different institutions performed injections. The generalizability of our findings is limited by the known weakness of nonrandomized study design. However, the multicenter design improves the generalizability of this study. Loss to follow-up was also a concern, and hence for full clarity, calculations were performed with data available and for a worst-case scenario, assuming that the treatment failed in all subjects who were lost to follow-up. Regardless of the statistics utilized, the groups did not differ. Additionally, because of the retrospective nature of this study, outcome data were limited to NRS pain scores as the only validated outcome measure. Future study should include a validated functional outcome measure. Overall success rates must be interpreted with caution. The reported rates of success here are lower than those of other reported studies and are likely due to the selection bias of a group of patients with chronic radicular pain and also an objective diagnosis of radiculopathy confirmed by EMG. Although the comparison between groups is valid, we caution against universally applying these findings as an excepted outcome from the majority of patients undergoing a lumbar TFESI, particularly those with acute and subacute pain.
Conclusions This study demonstrates no significant differences in pain reduction or the number of repeat injections with particulate compared with nonparticulate transforaminal epidural steroid injection in patients with EMG-confirmed painful lumbosacral radiculopathy. These findings suggest a new population for whom a nonparticulate steroid appears to be an appropriate first-line therapy, although confirmation with a randomized study is needed.
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pain due to intervertebral disc herniation: A prospective, randomized, double-blind trial. Pain Med 2014;15:548-555. Collighan N, Gupta S, Richardson J, Cheema S. Re: Comparison of the effectiveness of lumbar transforaminal epidural injection with the particulate and nonparticulate corticosteroids in lumbar radiating pain. Pain Med 2011;12:1290-1291; author reply 1292. Kim D, Brown J. Efficacy and safety of lumbar epidural dexamethasone versus methylprednisolone in the treatment of lumbar radiculopathy: A comparison of soluble versus particulate steroids. Clin J Pain 2011;27:518-522. Park CH, Lee SH, Kim BI. Comparison of the effectiveness of lumbar transforaminal epidural injection with particulate and nonparticulate corticosteroids in lumbar radiating pain. Pain Med 2010;11:1654-1658. Marchetti J, Verma-Kurvari S, Patel N, Ohnmeiss DD. Are electrodiagnostic study findings related to a patient’s response to epidural steroid injection? PM R 2010;2:1016-1020. Dillingham TR, Lauder TD, Andary M, et al. Identifying lumbosacral radiculopathies: An optimal electromyographic screen. Am J Phys Med Rehabil 2000;79:496-503. Waschke A, Hartmann C, Walter J, et al. Denervation and atrophy of paraspinal muscles after open lumbar interbody fusion is associated with clinical outcomedelectromyographic and
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CT-volumetric investigation of 30 patients. Acta Neurochir (Wien) 2014;156:235-244. Hu Y, Leung HB, Lu WW, Luk KD. Histologic and electrophysiological changes of the paraspinal muscle after spinal fusion: An experimental study. Spine (Phila Pa 1976) 2008;33:1418-1422. April C, Bogduk N, Dreyfuss P, et al. Practice Guidelines for Spinal Diagnostic & Treatment Procedures. 1st ed. San Rafael, CA: International Spine Intervention Society; 2004. Meikle AW, Tyler FH. Potency and duration of action of glucocorticoids. Am J Med 1977;63:200. Ghahreman A, Ferch R, Bogduk N. The efficacy of transforaminal injection of steroids for the treatment of lumbar radicular pain. Pain Med 2010;11:1149-1168. Friedly JL, Comstock BA, Turner JA, et al. A randomized trial of epidural glucocorticoid injections for spinal stenosis. N Engl J Med 2014;371:11-21. McCormick Z, Cushman D, Casey E, Garvan C, Kennedy DJ, Plastaras C. Factors associated with pain reduction after transforaminal epidural steroid injection for lumbosacral radicular pain. Arch Phys Med Rehabil 2014;95:2350-2356. Mattie R, McCormick Z, Yu S, Kennedy DJ, Levin J. Are all epidurals created equally? A review of the literature on caudal, interlaminar, and transforaminal injections from the last 5 years. Curr Phys Med Rehabil Rep 2015;3:159-172.
Disclosure Z.M. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605. Address correspondence to: Z.M.; e-mail: [email protected] Disclosure: nothing to disclose D.C. Department of PM&R, University of Utah, Salt Lake City, UT Disclosure: nothing to disclose B.M. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: nothing to disclose M.C. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: nothing to disclose J.P. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: nothing to disclose L.G. Department of Pediatrics, Northwestern University Lurie Children’s Hospital, Chicago, IL Disclosure: nothing to disclose C.E. Department of PM&R, Harvard Medical School/Spaulding, Boston, MA Disclosure: nothing to disclose S.M. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: nothing to disclose
A.B. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: nothing to disclose S.K.C. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: nothing to disclose C.M. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: Other, American Board of Electrodiagnostic Medicine, Board of Directors, Exam Committee and Credentials Committee member D.R.W. Department of Anesthesia, Northwestern Feinberg School of Medicine, Chicago, IL Disclosure: nothing to disclose J.P. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: nothing to disclose C.P. Department of PM&R, University of Pennsylvania, Philadelphia, PA Disclosures outside this publication: patents, Dr Plastaras has a copyright RICPLAS licensed D.J.K. Department of Orthopaedics, Stanford University, Palo Alto, CA Disclosure: nothing to disclose Submitted for publication October 29, 2015; accepted March 31, 2016.
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Original Research
Pain Reduction and Repeat Injections After Transforaminal Epidural Injection With Particulate Versus Nonparticulate Steroid for the Treatment of Chronic Painful Lumbosacral Radiculopathy
Zachary McCormick, MD, Daniel Cushman, MD, Benjamin Marshall, DO, Mary Caldwell, DO, Jaymin Patel, MD, Leda Ghannad, MD, Christine Eng, MD, Steven Makovitch, DO, Ashwin Babu, MD, Samuel K. Chu, MD, Christina Marciniak, MD, David R. Walega, MD, Joel Press, MD, Christopher Plastaras, MD, David J. Kennedy, MD
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Steroids for EMG-Confirmed Painful Radiculopathy
in all known cases of epidural steroid injectionerelated spinal cord infarctions [3-10]. The larger size or aggregation of particulate steroids [2,11] likely obstructs arteriolar blood flow to the spinal cord if these steroids are inadvertently injected into radicular arteries during TFESI [12-15]. Further, several studies have demonstrated that dexamethasone, the only nonparticulate steroid available for clinical use, is not inferior to particulate corticosteroids with regard to pain reduction and functional improvement, therefore justifying its use as a first-line medication for TFESI in the treatment of lumbosacral radicular pain [16-18]. Prior studies have directly compared the efficacy of dexamethasone and various particulate corticosteroids including triamcinolone, betamethasone, and methylprednisolone with varying results for lumbosacral radicular pain [16-20]. Four studies suggested minimal to no difference in clinical outcomes when using a particulate versus nonparticulate steroid during TFESI [16-18] and interlaminar epidural steroid injection [19], whereas one study suggested superior outcomes associated with the use of a particulate steroid compared with a nonparticulate steroid during repeat TFESIs in which the first injection was not effective [20]. Radiating leg pain has a wide differential diagnosis, and although injections are often administered for radicular pain, no study to date has compared the efficacy of particulate and nonparticulate steroids for the treatment of radicular pain with needle electromyography (EMG)-confirmed radiculopathy. The aim of the present study was to determine if TFESI with particulate or nonparticulate steroid is associated with greater reduction of pain or a reduction in the number of repeat injections in the treatment of the specific patient population with needle EMG-confirmed lumbosacral radiculopathy. Methods This retrospective cohort study was approved by respective Institutional Review Boards at 2 interventional spine practices in urban tertiary academic medical centers between May 2007 and December 2013. The data used in this study were obtained by retrospective query of the electronic medical record at both institutions. Consecutive patients aged 18 years or older who demonstrated EMG-confirmed painful lumbosacral radiculopathy and also underwent a TFESI within 6 months of the EMG for treatment of pain were included, consistent with criteria used in a prior investigation [21]. EMGs were obtained at the discretion of the treating physician and were not considered routine care. EMG-confirmed radiculopathy was defined as more than one muscle abnormality in a discrete myotome but different nerve distributions on at least a 6-muscle screen including paraspinal muscles or at least an 8-muscle screen without paraspinal muscles, with
changes consistent with denervation including positive waves, fibrillation potentials, large amplitude and duration motor units, and polyphasic motor units of significant amplitude (“neuropathic”) to be distinguished from “myopathic” motor units [22]. Pain was considered radicular in character when history was consistent with lancinating pain radiating to a limb in a distribution corresponding to the involved nerve root according to EMG testing. The diagnosis of radicular pain was also supported by concordant disease on magnetic resonance imaging (MRI) of the lumbosacral spine. Patients were excluded from the analysis if an epidural steroid injection (ESI) was performed more than 6 months after the EMG was performed or if the patient had an ESI in the 6 months prior to the EMG. Patients with a history of prior spinal surgery were excluded, because this intervention can confound EMG findings used in the electrodiagnosis of radiculopathy, particularly in the paraspinal muscles [23,24]. In this study, the following data were analyzed: age, gender, body mass index, duration of radicular symptoms, alcohol use, symptom cause related to a motor vehicle accident, disability status, reason for obtaining an EMG, MRI diagnosis concordant with the affected spinal nerve root determined by EMG, numerical rating scale (NRS) pain scores, steroid type used during TFESI, repeat TFESI treatments, and time to follow-up. At both institutions, standard clinical protocol included a patient return visit 2-4 weeks after the injection and a second follow-up visit 8-12 weeks after the injection to reassess symptoms and physical functioning. Each injection was ordered and performed by a physician who was board certified in Physical Medicine and Rehabilitation and also had additional subspecialty board certification in either Pain Medicine or Sports Medicine. Nine different attending physicians who had between 5 and 14 years of clinical experience of interventional spine care performed these injections. In all patients, single-level, unilateral TFESIs were performed using a standard, fluoroscopy-guided subpedicular technique [25]. The patient was placed prone and the skin was prepped using sterile technique. The fluoroscope was positioned to obtain an oblique view of the subpedicular space. The skin and soft tissue were anesthetized using 1% lidocaine (preservative free). A sterile 22-gauge 3.5-, 5-, or 7-inch spinal needle was then advanced to the superior aspect of the neural foramen above the exiting spinal nerve. Anteriorposterior, oblique, and lateral fluoroscopic views were obtained to confirm accurate needle placement. Subsequently, 1-2 mL of contrast dye (Isovue 300, Bracco Diagnostics Inc, Monroe, NJ) was injected through microbore tubing with use of live fluoroscopy. If intravenous dye uptake occurred, the needle was repositioned until intravenous uptake was absent and an epidural flow pattern was evident. If intra-arterial, intrathecal, or intradiskal flow was identified, the
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procedure was aborted. A total of 1.5-2 mL of corticosteroid (15 mg dexamethasone sodium phosphate [10 mg/mL], 12 mg betamethasone acetate [6 mg/mL], or 80 mg triamcinolone acetonide [40 mg/mL]; equipotent doses [26]) was injected. The type of steroid used varied over time, with betamethasone or triamcinolone (particulate steroids) used almost exclusively during the earlier study dates, with a gradual transition around the year 2010 on a clinician-to-clinician basis to use of dexamethasone (a nonparticulate steroid) that was used almost exclusively because of safety concerns related to the use of particulate steroids during TFESI and the possibility of spinal cord infarction. Repeat injections were never performed routinely; rather, this decision was made at the discretion of the treating attending physician. Data Analysis Proportions for categorical variables in addition to means and standard deviations (SDs) for continuous variables were calculated. Follow-up was categorized as <30 days (short term) and 30 days (intermediate). The primary outcome measure for this study was the proportion of patients who experienced 50% reduction of pain on the NRS after TFESI at short-term follow-up. Secondary outcomes included the mean change in NRS and the mean number TFESIs performed, as well as the proportion of patients who received a repeat TFESI. The particulate steroid group was compared with the nonparticulate steroid group with regard to these outcome measures. Primary analysis excluded patients who were lost to follow-up. Additional “best” and “worst” case scenario analyses were performed to account for the possible range of “true” pain outcomes given loss to follow-up. The best-case scenario analysis assumes that all patients lost to follow-up experienced 50% improvement in NRS pain score. The worst-case scenario analysis assumes that all patients lost to follow-up experienced <50% improvement in NRS pain score. Groups were stratified by demographic and clinical characteristics to identify confounding group differences. Statistical Analysis Data were checked for normal distributions using summary statistics and graphical displays. The c2 statistic was used to compare categorical variables, and analysis of variance was used to compare numerical variables. Data were analyzed using PSPP version 0.8.3 (Gnu Project, Boston, MA). The level of significance was set at .05 for all statistical tests. Two-sided testing was used for all hypothesis testing.
3
Results A total of 78 consecutive patients with EMGconfirmed lumbosacral radiculopathy received a TFESI for painful radiculopathy during the study time frame. Eight patients (10%) were lost to follow-up at short-term follow-up (3 from the particulate group and 5 from the nonparticulate steroid group). An additional 22 patients (28%) were lost to follow-up at intermediate follow-up (12 from the particulate group and 18 from the nonparticulate steroid group). Demographic, clinical, and procedural characteristics of the study population are shown in Table 1. The mean age SD was 56 16 years, and the mean duration of symptoms prior to ESI was 49 71 months. Forty-one patients (52%) received a nonparticulate steroid (dexamethasone) and 37 patients (48%) received a particulate steroid (triamcinolone, n ¼ 23 [30%]; betamethasone, n ¼ 14 [18%]). Seventy patients (90%) received an EMG to clarify the diagnosis. The mean SD time to short-term follow-up after the injection was 18 6 days, and the time to intermediate follow-up was 86 55 days. Baseline demographic, clinical, and procedural characteristics of patients who received a particulate steroid were compared with those of patients who received a nonparticulate steroid (Table 1). The particulate group had a shorter duration of symptoms before the intervention compared with the nonparticulate group (32 versus 79 months, P ¼ .03). More patients who received a particulate steroid compared with a nonparticulate steroid had an MRI diagnosis of disk herniation or a disk bulge contacting a spinal nerve root that was concordant with the level of radiculopathy defined by EMG (P ¼ .03). Both the particulate and nonparticulate groups had similar proportions of patients who required repeat TFESI (27% versus 39%, P > .05). No statistically significant difference was found in the proportion of patients who reported 50% pain reduction on the NRS between the particulate and nonparticulate groups at short-term follow-up (35%; 95% confidence interval [CI], 19-51 versus 28%; 95% CI, 1343, respectively) or at intermediate follow-up (40%; 95% CI, 21-59 versus 39%; 95% CI, 19-59, respectively; Table 2). The best- and worst-case scenario analyses for pain outcomes also demonstrated no significant differences between these groups (Table 3). No difference was found in the mean number of injections administered between groups by the time of intermediate follow-up (P ¼ .26). In comparing demographic, procedural, and outcome data between the 2 centers, nonparticulate steroids were used more frequently than particulate steroids (P < .001). No other significant differences were found between the 2 centers (P > .05 in all other comparisons). These data included age, gender, BMI, duration of symptoms, alcohol consumption, disability, pain related
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Steroids for EMG-Confirmed Painful Radiculopathy
561 Table 1 562 Characteristics of patients with needle electromyography-proven painful radiculopathy, stratified by those who received transforaminal epidural Q3 563 particulate versus nonparticulate steroid injection
Variable Age, y Gender, % female BMI, kg/m2 Duration of symptoms, mo >3 drinks/day Tobacco use Symptoms associated with MVC Receiving disability benefits Reason for EMG Clarify diagnosis of radiculopathy versus other disease Clarify nerve root level MRI diagnosis concordant with affected spinal nerve root determined by EMG* Disk herniation or bulge contacting nerve root Central canal stenosis Neural foraminal stenosis Only disk herniation or bulge contacting nerve root Only central stenosis Only foraminal stenosis Only central and/or foraminal stenosis Mean time to short-term follow-up (<30 days), days Mean time to intermediate follow up (30 days), days NRS prior to injection
All Patients n ¼ 78 Mean (SD) or n (%)
Particulate Steroid Group n ¼ 37 Mean (SD) or n (%)
Nonparticulate Steroid Group n ¼ 41 Mean (SD) or n (%)
56 38 30 49 1 9 4 3
58 19 30 32 1 3 1 1
56 20 30 71 0 6 3 2
(16) (49%) (7) (71) (3%) (14%) (6%) (5%)
(16) (51%) (5) (51) (3%) (10%) (3%) (3%)
(16) (49%) (8) (86) (0%) (18%) (9%) (6%)
.54 .63 .92 .03 .64 .41 .26 .65 .55
70 (90%) 8 (10%)
34 (92%) 3 (8%)
36 (88%) 5 (12%)
49 22 22 32 4 4 14 18 86 6
24 7 6 19 2 1 4 17 88 6
25 15 16 13 2 3 10 18 84 6
(70%) (31%) (31%) (46%) (6%) (6%) (20%) (6) (55) (3)
(77%) (23%) (19%) (61%) (6%) (3%) (13%) (7) (64) (3)
P Value
(62%) (38%) (52%) (33%) (5%) (8%) (26%) (5) (44) (2)
.30 .20 .07 .03 1.0 1.0 .24 .37 .80 .96
SD ¼ standard deviation; BMI ¼ body mass index; MVC ¼ motor vehicle collision; EMG ¼ electromyography; MRI ¼ magnetic resonance imaging; NRS ¼ numerical rating scale. * MRI diagnosis not available in 8 patients; 6 missing from the particulate group and 2 from the nonparticulate group.
to a motor vehicle accident, baseline NRS pain score, decrease in mean decrease in pain scores at short- and long-term follow-up, and proportion of responders (50% reduction in NRS pain score). No catastrophic adverse events of TFESI occurred in this study (ie, vascular or neurologic compromise).
Discussion This investigation is the first to compare clinical outcomes of the use of epidural particulate and nonparticulate steroids for the treatment of radicular pain in patients with proven objective nerve root disease.
Table 2 Particulate versus nonparticulate steroid group comparison of numerical rating scale pain score improvement and repeat transforaminal epidural steroid injections in patients with needle electromyography-proven painful radiculopathy Outcome
Data Available, n
Short-term follow-up* 50% NRS improvement <50% NRS improvement Intermediate follow-up† 50% NRS improvement <50% NRS improvement Short-term follow-up* Mean NRS improvement Intermediate follow-up* Mean NRS improvement Mean No. of repeated TFESIs
70
Particulate Steroid Group Mean (SD) or n (%; 95% CI)
Nonparticulate Steroid Group Mean (SD) or n (%; 95% CI)
P Value
12 (35; 19-51) 22 (65; 49-81)
10 (28; 13-43) 26 (72; 57-87)
.50
10 (40; 21-59) 15 (60; 41-79)
9 (39; 19-59) 14 (61; 41-81)
.95
48
70 48
3.5 (4.2) 2.8 (5.1)
2.1 (7.5) 3.4 (4.6)
.33 .65
48
0.4 (0.7)
0.6 (0.9)
.15
SD ¼ standard deviation; CI ¼ confidence interval; NRS ¼ numerical rating scale; TFESI ¼ transforaminal epidural steroid injection. * Short-term follow-up corresponds to <30 days. † Intermediate follow-up corresponds to 30 days. FLA 5.4.0 DTD PMRJ1687_proof 11 April 2016 1:13 pm ce
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721 722 723 Particulate Steroid Group Nonparticulate Steroid Group 724 725 Outcome n (%; 95% CI) n (%; 95% CI) P Value 726 Best-case scenario 727 † 728 Short-term follow-up .72 729 50% NRS improvement 15 (41; 25-57) 15 (37; 22-52) 730 <50% NRS improvement 22 (59; 43-75) 26 (63; 48-78) 731 ‡ Intermediate follow-up .56 732 50% NRS improvement 22 (59; 43-75) 27 (66; 52-81) 733 <50% NRS improvement 15 (41; 25-57) 14 (34; 20-49) 734 735 Worst-case scenario 736 Short-term follow-up† .43 737 50% NRS improvement 12 (32; 17-47) 10 (24; 11-37) 738 <50% NRS improvement 25 (68; 53-83) 31 (76; 63-89) 739 Intermediate follow-up‡ .60 740 50% NRS improvement 10 (27; 13-41) 9 (22; 9-35) 741 742 <50% NRS improvement 27 (73; 59-87) 32 (78; 65-91) 743 CI ¼ confidence interval; NRS ¼ numerical rating scale. 744 * The best-case scenario assumes that all patients lost to follow-up experienced 50% improvement in NRS pain score. The worst-case scenario Q4 745 746 assumes that all patients lost to follow-up experienced <50% improvement in NRS pain score. † 747 Short-term follow-up corresponds to <30 days. 748 ‡ Intermediate follow-up corresponds to 30 days. 749 750 751 752 included only patients with acute lumbar disk herniaThis study suggests that there is no significant disad753 tions, whereas the present data reflect persons with vantage of TFESI with the nonparticulate steroid, 754 755 chronic symptoms due to any structural cause. dexamethasone, compared with 2 particulate steroids, 756 It is interesting and unexpected that although isotriamcinolone and betamethasone, for reduction of pain 757 lated disk herniations or disk bulges contacting a spinal or number of injections in patients with EMG-confirmed 758 759 nerve root (with no concomitant foraminal or central lumbosacral radiculopathy. 760 stenosis) were the more prevalent identified structural These results build on the emerging literature 761 762 cause of EMG-confirmed radiculopathy in the particucomparing the effectiveness of nonparticulate versus 763 late group than in the nonparticulate group (P ¼ .03), particulate steroids in epidural steroid injections for 764 765 the particulate group did not experience a greater radicular pain [16-20]. Evidence suggests that no sig766 likelihood of clinically significant pain reduction nificant difference exists in clinical outcomes when 767 compared with the nonparticulate group. This finding is nonparticulate or particulate steroids are used for TFESI 768 769 striking given that TFESI for lumbosacral disk herniation in patients with radicular pain. In one study, 770 has generally been demonstrated to be more effective El-Yahchouchi et al [16] compared dexamethasone with 771 772 than TFESI for lumbar spinal stenosis [27-30]. This triamcinolone or betamethasone in a large retrospective 773 finding may further speak to the justified use of a nonstudy (n ¼ 2634) of patients with lumbosacral radicular 774 particulate steroid as a first-line treatment in this pain, and no significant difference in pain or functional 775 776 population. outcomes was demonstrated at 2 months. Kennedy et al 777 [17] compared dexamethasone with triamcinolone for 778 779 Limitations the treatment of lumbosacral radicular pain due to an 780 acute disk herniation in a randomized, double-blind trial 781 This unique study examined a patient population with of 78 patients and found no significant between-group 782 783 chronic radicular pain and radiculopathy confirmed by differences in pain reduction (NRS), functional 784 EMG, with the primary results generally consistent with improvement (Oswestry Disability Index), or rates of 785 786 the known literature on this topic. However, this study surgical intervention. 787 has several limitations. First, because EMGs were not Although the present findings are generally consistent 788 789 the standard of care for all patients with radicular pain, with prior studies, in the present study there was no 790 only a subset of patients actually underwent this testing statistically significant difference in the need for repeat 791 at the discretion of the treating physician. The typical TFESIs, in contrast to the study by Kennedy et al [17], in 792 793 indication for an EMG was to confirm the diagnosis in the which it was found that patients treated with dexa794 setting of an unclear clinical picture when symptoms methasone required a greater mean number of repeat 795 796 and physical examination findings did not clearly injections to achieve a successful clinical outcome 797 correlate with imaging findings. Therefore, the patients compared with patients treated with particulate ste798 undergoing this additional testing may not be the same roids. This difference may be related to the differences 799 800 as those with clear single-level radicular pain and in our study population, because Kennedy et al [17]
Table 3 Best and worst-case scenario pain outcomes (n ¼ 78)
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Steroids for EMG-Confirmed Painful Radiculopathy
concordant MRI imaging. Also, while limiting this study to the unique cohort of only patients who had EMG positive radiculopathy, the radiculopathy identified could be due to different diseases such as a disk herniation or spinal stenosis. These diseases have different natural histories and could possibly have different responses to treatment. However, given that the goal of the study was to compare the pain outcomes of the 2 groups, this heterogeneity should have been equally distributed between groups as evidenced by the fact that the only variable that was significantly different between the cohorts was a longer duration of symptoms prior to intervention in the nonparticulate steroid group. The type of steroid used changed over time, with betamethasone or triamcinolone used almost exclusively during the earlier study dates and a gradual transition around 2010 on a clinician-to-clinician basis to dexamethasone that was used almost exclusively because of safety concerns related to the use of particular steroids during TFESI and the possibility of spinal cord infarction. Randomized study in the future is needed to confirm the present results. There was no standardized protocol for repeating TFESIs. Rather, the decision to repeat an injection was made at the discretion of the treating attending physician on a case-by-case basis that never included a “reflex” or “automatic” repeat TFESI. Although this protocol introduces an element of variability, it is representative of realistic clinical practice, and it improves the generalizability of the present findings, because multiple attending physicians at 2 different institutions performed injections. The generalizability of our findings is limited by the known weakness of nonrandomized study design. However, the multicenter design improves the generalizability of this study. Loss to follow-up was also a concern, and hence for full clarity, calculations were performed with data available and for a worst-case scenario, assuming that the treatment failed in all subjects who were lost to follow-up. Regardless of the statistics utilized, the groups did not differ. Additionally, because of the retrospective nature of this study, outcome data were limited to NRS pain scores as the only validated outcome measure. Future study should include a validated functional outcome measure. Overall success rates must be interpreted with caution. The reported rates of success here are lower than those of other reported studies and are likely due to the selection bias of a group of patients with chronic radicular pain and also an objective diagnosis of radiculopathy confirmed by EMG. Although the comparison between groups is valid, we caution against universally applying these findings as an excepted outcome from the majority of patients undergoing a lumbar TFESI, particularly those with acute and subacute pain.
Conclusions This study demonstrates no significant differences in pain reduction or the number of repeat injections with particulate compared with nonparticulate transforaminal epidural steroid injection in patients with EMG-confirmed painful lumbosacral radiculopathy. These findings suggest a new population for whom a nonparticulate steroid appears to be an appropriate first-line therapy, although confirmation with a randomized study is needed.
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Disclosure Z.M. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605. Address correspondence to: Z.M.; e-mail: [email protected] Disclosure: nothing to disclose D.C. Department of PM&R, University of Utah, Salt Lake City, UT Disclosure: nothing to disclose B.M. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: nothing to disclose M.C. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: nothing to disclose J.P. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: nothing to disclose L.G. Department of Pediatrics, Northwestern University Lurie Children’s Hospital, Chicago, IL Disclosure: nothing to disclose C.E. Department of PM&R, Harvard Medical School/Spaulding, Boston, MA Disclosure: nothing to disclose S.M. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: nothing to disclose
A.B. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: nothing to disclose S.K.C. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: nothing to disclose C.M. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: Other, American Board of Electrodiagnostic Medicine, Board of Directors, Exam Committee and Credentials Committee member D.R.W. Department of Anesthesia, Northwestern Feinberg School of Medicine, Chicago, IL Disclosure: nothing to disclose J.P. Department of PM&R, Northwestern Feinberg School of Medicine/The Rehabilitation Institute of Chicago, 345 East Superior St, Chicago, IL 60605 Disclosure: nothing to disclose C.P. Department of PM&R, University of Pennsylvania, Philadelphia, PA Disclosures outside this publication: patents, Dr Plastaras has a copyright RICPLAS licensed D.J.K. Department of Orthopaedics, Stanford University, Palo Alto, CA Disclosure: nothing to disclose Submitted for publication October 29, 2015; accepted March 31, 2016.
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