Correlation Between Severity of Lumbar Spinal Stenosis and Lumbar Epidural Steroid Injection

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1 bs_bs_banner Pain Medicine 2014; 15: Wiley Periodicals, Inc. Correlation Between Severity of Lumbar Spinal Stenosis and Lumbar Epidural Steroid Injection Chan-Hong Park, MD, PhD,* and Sang-Ho Lee, MD, PhD *Department Anesthesiology and Pain Medicine, Dongrae Wooridul Spine Hospital, Daegu; Department of Neurosurgery, Wooridul Spine Hospital, Seoul, South Korea Reprint requests to: Chan-Hong Park, MD, PhD, Dongrae Wooridul Spine Hospital, 286 Chungruel-Daero Dongrae-gu, Busan , South Korea. Tel: ; Fax: ; Abstract Objective. Lumbar spinal stenosis (LSS) is a narrowing of the spinal canal that causes mechanical compression of the spinal nerve roots. The compression of these nerve roots can cause leg pain, as well as neurogenic claudication. Lumbar epidural steroid injections have commonly been used in patients with LSS. The aim of our study was to determine the relationship between the severity of LSS using a grading system (grade 1 = mild stenosis with separation of all cauda equina; grade 2 = moderate stenosis with some cauda equina aggregated; grade 3 = severe stenosis with none of the cauda equina separated) and the subject s response to computed tomography-guided lumbar epidural steroid injection (CTG-LESI) and to evaluate the short-term effectiveness. Methods. Forty-seven consecutive patients with degenerative LSS were enrolled in this prospective study. All subjects underwent lumbar spine magnetic resonance imaging. Two radiologists independently graded lumbar central canal stenosis based on T2-weighted axial images. All CTG-LESI were performed in the procedure room. Outcome measures were obtained using the 5-point patient s satisfaction scale at 2 and 8 weeks post-treatment. To evaluate the outcome, we divided the patients into two groups according to their response to the treatment. Results. Improvement (including reports of slightly improved, much improved, and no pain) was observed in 37 patients (78.7%) at 2 weeks and 36 patients (77.6%) at 8 weeks after the procedure. There was no statistically significant correlation between pain relief and age. Conclusions. The grade of LSS appears to have no effect on the degree of pain relief associated with CTG-LESI. However, CTG-LESI seems to provide effective short-term pain relief due to LSS. Key Words. Epidural (Injection Space); Pain Management Introduction Lumbar spinal stenosis (LSS) is a common degenerative disease. Spinal stenosis can be defined as a narrowing of the spinal canal by a combination of bone and soft tissues that causes mechanical compression of the spinal nerve roots. The compression of these nerve roots can be asymptomatic, but it can also become symptomatic, resulting in weakness, reflex alterations, gait disturbances, bowel or bladder dysfunction, motor and sensory changes, radicular pain or atypical leg pain, and neurogenic claudication [1,2]. Stenosis may occur in any spinal canal region including the central, lateral recess, foraminal, and extraforaminal regions [1,3 6]. Treatment modalities for LSS vary and include medication, exercise, steroid injections, and surgery [7]. Lumbar epidural steroid injection has commonly been used in patients with LSS and or disc herniation [2,6,8 14]. However, the effects of this treatment are various [10]. One study reported that fluoroscopically guided caudal epidural steroid injection is effective for the management of LSS for up to 2 years [15]. In Botwin et al. [16]., 75% of the patients had a successful long-term outcome, reporting at least a >50% reduction between pre-injection and post-injection pain scores, with an average of 1.9 injections per patient. 556

2 Effect of LESI on LSS Severity The correlation between the degree of LSS and clinical symptoms has been reported [17,18]. The degree of radiographic LSS has not been shown to be correlated with clinical symptoms or Oswestry Disability Index percentage scores [3,17]. In addition, Park et al. demonstrated that the lumbar dural sac cross-section area did not correlate with the efficacy of percutaneous adhesiolysis [19]. Campbell et al. reported on the correlation of the spinal canal dimensions with the efficacy of epidural steroid injections in spinal stenosis [18]. In this study, the authors have focused on the transverse canal diameter, the transverse osseous canal diameter, and the anterior posterior diameter to grade LSS, and reported that the spinal canal dimension is not predictive of the success or failure of epidural steroid injection in patients with spinal stenosis. Recently a new grading system for lumbar central canal stenosis on magnetic resonance images (MRI) was reported [20], which uses the relative ratio of the cauda equina and remaining cerebrospinal fluid (CSF) space of the dural sac. To our knowledge, there has been no report regarding a correlation between the response to CT-guided lumbar epidural steroid injection (CTG-LESI) and the degree of spinal stenosis using this grading system [20]. The aim of the current study was to determine the relationship between the severity of LSS with a grading system and the subject s response to CTG-LESI, and to evaluate the short-term outcome. Methods Forty-seven patients with degenerative LSS were enrolled in this study. The diagnosis of LSS was made based on clinical symptoms, neurological examinations, and imaging studies that included plain radiography as well as MRI of the lumbar spine. All subjects obtained Institutional Review Board approval and signed an informed consent form. other; grade 2: defined as moderate LCCS, in which the anterior CSF space was moderately obliterated and some of the cauda equina were aggregated, making it impossible to visually separate them; and grade 3: defined as severe LCCS, in which the anterior CSF space was obliterated so severely as to show marked compression of the dural sac, and none of the cauda equina could be visually separated from each other, appearing instead as one bundle [20]. Two radiologists blind to the patient s clinical symptoms and radiologic reports scored the images. All procedures were performed with a CT unit (Big Bore, Philips, Cleveland, OH, USA). Patients were prepared on the radiological table in the prone position and a wire marking device was placed at a suitable location on the low back and scanning of the pelvis was acquired at 120 kv and 60 ma; the slice diameter and index were 1 mm. Scans were acquired of the undersurface of the posterior lumbar spinous process. From this view, the distance between, as well as the introduction angle to the epidural spaces were measured at the same level with the lesion for all subjects (Figure 1). After marking the skin at the appropriate spot near the midline, the area was sterilized and anesthetized. A 22-gauge Tuohy needle was then advanced partially into the patient and the needle was then advanced downward onto the outer aspect of the ligamentum flavum by using intermittent CT guidance. The stylet was removed and 10 ml of sterile nonbacteriostatic saline was attached via short connection tubing. Once the needle placement was in the epidural space, the needle was slowly advanced into the epidural space by using the loss-of-resistance technique, and 0.5 ml of contrast agent (Omnipaque 300; Amersham, UK) was injected to confirm the epidural space (Figure 2A and 2B). A final image was obtained to show the epidural space with the contrast medium, the The inclusion criteria for the current study were that all of the patients had to have symptoms typical of lumbar spinal stenosis, i.e., radicular pain, claudication, or radiculopathy, with clear evidence of central canal stenosis on the cross-sectional images from the spinal MRI. The exclusion criteria were an unclear description of symptoms, low back pain without symptoms in a leg, foraminal or extraforaminal stenosis on the cross-sectional images, spondylolisthesis, or previous back surgery. All subjects underwent lumbar spine MRI (Achieva 1.5T, Philips, Best, The Netherlands). T2 axial images were obtained. The image matrix was pixels, the field of view was 16 cm, the section thickness was 4 mm, the intersection gap was 0.44 mm, and the echo train lengths were 25 for the T2-weighted imaging. The grading of LSS was divided according to the grading system: grade 1: defined as mild lumbar central canal stenosis (LCCS), in which the anterior CSF space was mildly obliterated, but all cauda equina could be clearly separated from each Figure 1 Initial scout image shows the lumbar epidural space at L4 5. The distance tool was used to calculate the appropriate skin entry site. 557

3 Park and Lee nonsteroidal antiinflammatory drugs and muscle relaxants. In addition, patients who were nonresponsive to this therapy were given opioid or nonopioid analgesics after the first follow-up. However, during 8 weeks of follow-up, the patients did not receive any ESI. Outcome measures were obtained with the Roland 5-point patient s satisfaction scale (0: absence of pain; 1: little pain; 2: moderate pain; 3: bad pain; 4: very bad pain; 5: almost unbearable pain) [21] to assess the response to the procedure after 2 weeks and 8 weeks. To evaluate the correlations between pain reduction and age, gender, and severity of LSS, we divided the patients into two groups according to their response to the procedure: these groups reported either improvement (Roland scale 0 2) or not (Roland scale 3 5). Age differences were evaluated by Mann Whitney U-test and differences due to gender were evaluated using the Fisher s exact test. Correlations between pain relief and the LSS grading system were evaluated by the Spearman s rho correlation analysis. Results The 47 patients in this study diagnosed with LSS ranged in age from 21 to 72 years of age, with a mean age of 45.8, and consisted of 21 men and 26 women. The levels and sites of the affected regions are shown in Table 1: L4/5 was the most frequently implicated region. Improvement (including no pain, much improved, and slightly improved) was observed in 37 patients (78.7%) at 2 weeks after the procedure, and in 36 patients (76.6%) at 8 weeks (Table 2). Of the patients who improved, none were taking any analgesics or receiving other health care at 2 weeks, but one patient took analgesics at 8 weeks follow-up. There were no operations during the follow-up period. The frequency and percentage according to LSS grade are Figure 2 A CT image reveals that the epidural needle was placed in the L4 5 epidural space (A), and shows the contrast material had spread to the lumbar epidural space (B). appropriate needle placement, and the lack of intrathecal contrast medium. Once the appropriate epidural needle placement was confirmed, a combination of 2 mg of preservative-free ropivacaine (Naropine, Astrazeneca, Macclesfield, UK), 1,500 units of hyaluronidase and 40 mg of triamcinolone acetonide, for a total volume of 3 5 ml was injected into the epidural space. The first follow-up after the procedure was performed 2 weeks later. During these 2 weeks, all subjects received Table 1 The characteristics of 47 patients with lumbar spinal stenosis who were treated with CT-guided epidural injection of steroids Frequency % Age 45.9 ± 13.0 Sex Male Female Level L2/ L3/ L4/ L5/S Grade of stenosis

4 Effect of LESI on LSS Severity shown in Table 1. There were 34 patients (72.4%) who had either grade 1 or 2 LSS. No significant differences were found between the improved and unimproved groups in age and gender (Tables 3 and 4). In addition, there were no statistically significant correlations between pain relief and grade, or pain relief and age (r = ; 2 weeks, 8 weeks, respectively) (Table 5). Discussion The current report showed a reduction of pain in 76% of the LSS patients at 8 weeks following CTG-LESI. We found, however, that there was no correlation between pain relief and the LSS grading system. Our hypothesis was that the degree of severe LSS would correlate with lower pain relief following the procedure. However, we did not find any difference in the LSS grading system between patients who experienced improvement and those who did not. We used CT scanning to perform the ESI. CT-guided ESI provided less discomfort during the procedure. This is likely due to minimal needle manipulation, no contact with the periosteum, a path that traverses Table 2 Outcome measurement after CT-guided lumbar epidural steroid injection were obtained with the Roland 5-point patient s satisfaction scale Response 2 weeks after procedure 8 weeks after procedure 0 8 (17.0%) 3 (6.4%) 1 19 (40.4%) 19 (40.4) 2 10 (21.3%) 14 (29.8%) 3,4 8 (17.0%) 6 (12.8%) 5 2 (4.3%) 5 (10.6%) Total 47 (100%) 47 (100%) 0 = absence of pain; 1 = little pain; 2 = moderate pain; 3 = bad pain; 4 = very bad pain; 5 = almost unbearable pain. Table 3 Age differences were evaluated by Mann Whitney U-test, and differences due to gender were evaluated using the Fisher s exact test between patients with improvement and no improvement at 2 weeks follow-up Improvement (N = 37) No improvement (N = 10) P Age (year) 45.8 ± ± Gender Male 15 (40.5%) 6 (60.0%) Female 22 (59.5%) 4 (40.0%) Table 4 Age differences were evaluated by Mann Whitney U-test, and gender differences were evaluated using the Fisher s exact test between patients with improvement and no improvement at 8 weeks follow-up Improvement (N = 36) No improvement (N = 11) P Age (year) 46.2 ± ± Gender Male 15 (41.7%) 6 (54.5%) Female 21 (58.3%) 5 (45.5%) Table 5 Correlations between pain relief and grade of stenosis, and pain relief and age were evaluated at 2 weeks and 8 weeks follow-up 2 weeks (N = 47) 8 weeks (N = 47) Grade Coefficient (r) P Age Coefficient (r) P minimum amount of muscle tissue, and an adjustment in the amount of injected fluid depending on the degree of stenosis present. For this reason, we used a small amount contrast (0.5 ml) and local anesthetics [22]. The choice of drugs used and the dosage for this kind of procedure for intervention remains controversial [23]. We used 2 mg of ropivacaine (0.2%, 1 ml) [24,25]. Ropivacaine is an amino amide local anesthetic with a shorter duration of action and less intense motor block compared with similar local anesthetics and is preservative-free [26]. Previous studies reported that there was no correlation between radiographic severity and clinical symptom or treatment outcome [18,19]. Our findings are consistent with the previous study, indicating that the spinal canal dimension, measured with a digital caliper using CT imaging, is not predictive of the success or failure of epidural steroid injection in patients with spinal stenosis [18]. The uniplanar spinal canal dimensions may not be fully reflective of the pathology of spinal stenosis, and multiple sites of compression and/or the cephalad/caudad extension of the compression may contribute to whether spinal stenosis is symptomatic or not [3,18]. Another factor underlying the inconsistencies between symptoms and the degree of spinal canal stenosis is the use of static images using grading of LSS to grade LSS. The 559

5 Park and Lee symptoms of LSS tend to fluctuate considerably over time, and there is a wide variability in lumbar dimension among patients who do not have clinical spinal stenosis [3,19,27]. Consistent with the current work, previous studies have also failed the find a correlation to age, gender and pain relief [15]. Hyaluronidase is not generally considered standard of care. In this study, hyaluronidase was used because it is thought that it may relieve tissue edema [28]. There were several limitations to the present study. Outcomes were measured only by the patient s pain score. Functional outcomes or psychological variables were not measured, nor reduction in medication or the proportion of patients with 50% pain relief. However, given the lack of correlation between grade of stenosis and relief of pain, it seemed superfluous to investigate these secondary outcome measures. In conclusion, CTG-LESI appears to be effective in the short term for the treatment of pain related to LSS for a period of 8 weeks, but patient outcome does not seem to correlate with the degree of lumbar spinal stenosis. References 1 Botwin KP, Gruber RD. Lumbar spinal stenosis: Anatomy and pathogenesis. Phys Med Rehabil Clin N Am 2003;14: Simotas AC, Dorey FJ, Hansraj KK, Cammisa F Jr. Nonoperative treatment for lumbar spinal stenosis. Clinical and outcome results and a 3-year survivorship analysis. Spine (Phila Pa 1976) 2000;25: Discussions Sirvanci M, Bhatia M, Ganiyusufoglu KA, et al. Degenerative lumbar spinal stenosis: Correlation with Oswestry Disability Index and MR imaging. Eur Spine J 2008;17: Arbit E, Pannullo S. Lumbar stenosis: A clinical review. Clin Orthop Relat Res 2001;384: Spivak JM. Degenerative lumbar spinal stenosis. J Bone Joint Surg Am 1998;80: Boswell MV, Trescot AM, Datta S, et al. Interventional techniques: Evidence-based practice guidelines in the management of chronic spinal pain. Pain Physician 2007;10: Daffner SD, Wang JC. The pathophysiology and nonsurgical treatment of lumbar spinal stenosis. Instr Course Lect 2009;58: Koc Z, Ozcakir S, Sivrioglu K, Gurbet A, Kucukoglu S. Effectiveness of physical therapy and epidural steroid injections in lumbar spinal stenosis. Spine (Phila Pa 1976) 2009;34: Delport EG, Cucuzzella AR, Marley JK, Pruitt CM, Fisher JR. Treatment of lumbar spinal stenosis with epidural steroid injections: A retrospective outcome study. Arch Phys Med Rehabil 2004;85: Harrast MA. Epidural steroid injections for lumbar spinal stenosis. Curr Rev Musculoskelet Med 2008;1: Smith CC, Booker T, Schaufele MK, Weiss P. Interlaminar versus transforaminal epidural steroid injections for the treatment of symptomatic lumbar spinal stenosis. Pain Med 2010;11: Botwin KP, Gruber RD. Lumbar epidural steroid injections in the patient with lumbar spinal stenosis. Phys Med Rehabil Clin N Am 2003;14: Manchikanti L, Cash KA, McManus CD, Pampati V, Benyamin RM. Preliminary results of a randomized, double-blind, controlled trial of fluoroscopic lumbar interlaminar epidural injections in managing chronic lumbar discogenic pain without disc herniation or radiculitis. Pain Physician 2010;13:E Botwin KP, Natalicchio J, Hanna A. Fluoroscopic guided lumbar interlaminar epidural injections: A prospective evaluation of epidurography contrast patterns and anatomical review of the epidural space. Pain Physician 2004;7: Lee JW, Myung JS, Park KW, et al. Fluoroscopically guided caudal epidural steroid injection for management of degenerative lumbar spinal stenosis: Shortterm and long-term results. Skeletal Radiol 2010; 39: Botwin KP, Gruber RD, Bouchlas CG, et al. Fluoroscopically guided lumbar transformational epidural steroid injections in degenerative lumbar stenosis: An outcome study. Am J Phys Med Rehabil 2002;81: Athiviraham A, Yen D, Scott C, Soboleski D. Clinical correlation of radiological spinal stenosis after standardization for vertebral body size. Clin Radiol 2007;62: Campbell MJ, Carreon LY, Glassman SD, McGinnis MD, Elmlinger BS. Correlation of spinal canal dimensions to efficacy of epidural steroid injection in spinal stenosis. J Spinal Disord Tech 2007;20: Park CH, Lee SH, Jung JY. Dural sac cross-sectional area does not correlate with efficacy of percutaneous adhesiolysis in single level lumbar spinal stenosis. Pain Physician 2011;14: Lee GY, Lee JW, Choi HS, Oh KJ, Kang HS. A new grading system of lumbar central canal stenosis on 560

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