|Year : 2015 | Volume
| Issue : 3 | Page : 364-369
Epidural injection of methylprednisolone with levobupivacaine under CT guidance improve radicular pain in herniated disc versus spinal stenosis
Enas M Ashrey MD 1, Ashraf M Enite2, Samy M Abdelraouf3
1 Department of Anesthesia, Intensive Care and Pain Management, Faculty of Medicine for Girls, Al Azhar University, Cairo, Egypt
2 Department of Radiology, Faculty of Medicine for Girls, Al Azhar University, Cairo, Egypt
3 Department of Neurosurgery, Faculty of Medicine for Girls, Al Azhar University, Cairo, Egypt
|Date of Submission||10-Aug-2014|
|Date of Acceptance||12-Dec-2014|
|Date of Web Publication||29-Jul-2015|
Enas M Ashrey
Department of Anesthesia, Intensive Care and Pain Management, Al-zahraa University Hospital, Abbasia, Cairo 11517
Source of Support: None, Conflict of Interest: None
Epidural injections are commonly used for the treatment of low back pain in patients in whom conservative management has failed and who may wish to avoid surgery. Computed tomography guidance allows lumbar epidural injection to be performed rapidly, while allowing precise needle placement and proper placement of steroids near the pathologically inflamed nerve roots.
Patients and Methods
A total of 40 patients with chronic persistent lumbar radicular pain were allocated into two groups (20 patients each). The disc herniation (DH) group and the spinal stenosis (SS) group, each received a mixture of 40 mg of methylprednisolone plus 25 mg of 0.5% levobupivacaine+4 ml of saline 0.9% (both in a 10 ml syringe) through a paramedian interlaminar lumbar epidural injection. The visual analogue scale (VAS) was used, where 0 = no pain and 10 = the worst pain imaginable. The patient satisfaction scale (excellent, good, poor, bad) was assessed before injection, after 24 h, and 2 weeks, 3, and 6 months from injection; the need for repeated injection at less than 3 months and adverse events were also recorded.
There was a significant reduction in the VAS score at 24 h (group DH 4.3 ± 1.5 VS. group SS 5.8 ± 2.4) (P < 0.05) and 2 weeks after injection; patients in group DH had a significantly lower VAS score (3.2 ± 1.6) in relation to group SS (5.2 ± 1.5) (P<0.05), but there was highly significant reduction in VAS at 3 and 6 months in the DH group (2.4 ± 1.4, 1.6 ± 1.2) compared with the SS group (4.6 ± 1.5, 4.9 ± 2.4) (P <0.01). Repeated injections at less than 3 months were lesser in the DH group (20%) than in the SS group (55%) (P < 0.01). The patient satisfaction scale was significantly increased in group DH compared with group SS (P < 0.001), with no major adverse events in the DH group compared with the SS group (P < 0.01).
An interlaminar lumbar epidural injection of methylprednisiolone with levobupivacaine under computed tomography guidance provided effective pain relief in the herniated disc group compared with the SS group, because it was safe, simple, and more accurate.
Keywords: computed tomography-guided, paramedian interlaminar lumbar epidural steroids injection
|How to cite this article:|
Ashrey EM, Enite AM, Abdelraouf SM. Epidural injection of methylprednisolone with levobupivacaine under CT guidance improve radicular pain in herniated disc versus spinal stenosis. Ain-Shams J Anaesthesiol 2015;8:364-9
|How to cite this URL:|
Ashrey EM, Enite AM, Abdelraouf SM. Epidural injection of methylprednisolone with levobupivacaine under CT guidance improve radicular pain in herniated disc versus spinal stenosis. Ain-Shams J Anaesthesiol [serial online] 2015 [cited 2020 Feb 17];8:364-9. Available from: http://www.asja.eg.net/text.asp?2015/8/3/364/161704
| Introduction|| |
Patients with lumbar radicular pain, who are not severely restricted in their daily life activities by their pain or have no indication for spinal surgery because of major neurological deficits, are usually treated in an ambulatory setting with a multimodal spectrum of conservative treatments. This includes the use of analgesics, physical therapies, transcutaneous electrical nerve stimulation, acupuncture, etc. The level of evidence for any of these treatments is low  . Epidural injections are commonly used for the treatment of low back pain in patients in whom conservative management has failed and who may wish to avoid surgery.
The mechanism of action of epidural injections is not well understood. It is believed that neural blockade alters or interrupts nociceptive input  . Explanations for improvements are based in part on the pharmacological and physical actions of local anesthetics, corticosteroids, and other agents. It is believed that local anesthetics interrupt the pain-spasm cycle and reverberating nociceptor transmission, whereas corticosteroids reduce inflammation by inhibiting either the synthesis or the release of a number of proinflammatory substances and by causing a reversible local anesthetic effect  . The interlaminar approach has been touted as its entry can be directed more closely to the assumed site of pathology, requiring less volume than the caudal route, and it is less risky compared with the transforaminal (TF) approach , .
Computed tomography (CT) has not been a common way of performing these injections, primarily because of the time, the radiation dose, and limited scanner availability, although the technique produces excellent anatomic delineation and accurate needle placement. CT fluoroscopy allows lumbar epidural injection to be performed rapidly, while allowing precise needle placement with very low radiation doses to the operator and the patient. This technique is especially useful in patients with marked degenerative changes resulting in very narrow intralaminar spaces  .
The aim of this study was to evaluate the role of the epidural injection of methylprednisolone with levobupivacaine under CT guidance in providing lumbar radicular pain relief for herniated disc patients compared with spinal stenosis.
| Patients and methods|| |
This retrospective study was completed at Al-Zahraa University Hospitals between 2012 and 2013. After the approval of the hospital local ethical committee and written informed consent were obtained, 40 patients American Society of Anesthesiologists1-II were divided into two equal groups: group DH (the disc herniation group) and group SS (the spinal stenosis group); they were given methylprednisolone with levobupivacaine through a paramedian interlaminar (PIL) epidural injection under CT guidance. All patients had undergone initial physical examination by both a spine surgeon and a pain mangement physician, and the diagnosis of degenerative lumber disc herniation or spinal stenosis was confirmed by reviewing the MRI of the lumbosacral spine for patients who received epidural steroid injection (ESI) [Figure 1]a and b). The possible benefits and complications of the procedure were explained to the patient. Because it is often difficult to determine the origin of spinal pain, the patient is advised that the procedure may not be effective.
|Figure 1: The ESI technique demonstrated in a 47-year-old man with back pain. (a, b) MRI sagittal and axial T2 WI demonstrated L3 – 4 mild broadbase disc protrusion, which was more inclined to the left. (c) A CT image demonstrates the needle to be appropriately angled toward the epidural space. This image was taken at the lower part of the posterior spinous process; the opening used to access the epidural space, between the spinous process and the medial facet, is clearly seen. The small triangle of the posterior epidural fat is a useful landmark to aim for, although it is not present in some patients, particularly those with severe spinal stenosis. Notice how the needle has avoided the laminae during insertion, adding to the comfort level of the patient. (d, e) The final sagittal and coronal reformatted image in this study demonstrates the contrast medium outlining the epidural space, tracking along the anterior edge of the ligamentum flavum. Cross-filling is seen. CT, computed tomography; ESI, epidural steroid injection.|
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Inclusion criteria: patients with persistent pain for at least 2 months despite continual conservative treatment and physical therapy, and the presence of a clear morphologic correlative in the MRI scan for the clinically affected nerve root in the form of a disc protrusion/herniation and/or bony stenosis of the neuroforamen because of hypertrophic facet joints. Exclusion criteria: indications for immediate spinal surgery because of a relevant neurological deficit, prior spinal surgery, trauma, pain or sensory alterations in the lower limb due to other reasons (arthrosis, peripheral vascular disease, polyneuropathy), motor deficit, diabetes, oral anticoagulatiuon, and known adverse reactions to the medication used. Patients with multiple disc lesions, infection at the site of injection or neoplasm, and patients who received multiple injections within a 2-month period were also excluded. Patients who did not respond to the first injection with a pain reduction greater than 50% within the first 24 h were also excluded as this was considered to be a negative diagnostic sign. These patients were re-evaluated for their possible origin of pain, and in the majority of cases, they received further diagnostic injections.
Injections were administered with CT guidance by dual MDCT (GE Medical System, USA). We used mAs of 21 and a kVp of 120. All patients were asked to lie prone, with their heads turned to the contralateral side of the injection. The head and thighs were fixed with a CT table tape to prevent motion during the procedure. Patients were monitored with pulse oximetry, noninvasive blood pressure, and ECG. All resuscitation equipments were available. The PIL lumbar approach was utilized under CT guidance. Diagnostic CT images were obtained to localize the treatment level. Skin disinfection was performed by betadine (povidone-iodine) solution, and lidocaine 1% was used for the infiltration of the skin, the subcutaneous tissue, and the supraspinous and the interspinous ligaments using a 24 G needle.
Under CT guidance, a 22 G touhy needle was placed into the dorsal epidural space. The needle was advanced partially into the patient and the stylet was removed, and 10 ml of sterile saline was attached through a short connection tubing. The needle was advanced slowly into the epidural space using the loss-of-resistance technique; a CT image was obtained to gauge the depth and the angulation [Figure 1]c). The needle was then advanced downward into the outer aspect of the ligamentum flavum using intermittent CT guidance. To minimize patient discomfort, the tract was made to avoid contact with the periosteum and traverse the minimum amount of posterior musculature. The correct position of the needle tip was confirmed by injection of 1-2 ml of 10% diluted iodinated contrast material. We used iopamidol (Io-pamiro 300, 300 mg of iodine/ml; Bracco Diagnostics, Princeton, New Jersey, USA). Extradural and extravascular spread of contrast was documented with a CT scan. A final image was obtained to demonstrate the epidural spread of the contrast medium, appropriate needle placement, and lack of intrathecal contrast medium [Figure 1]c-e). When the needle is placed properly, the contrast medium will have a linear appearance. A corticosteroid solution of 40 mg (1 ml) methylprednisolone and 25 mg (5 ml) 0.5% levobupivacaine+4 ml of saline 0.9%, both in a 10 ml syringe, was then prepared, and injected slowly, followed by a 0-2 ml saline flush, and the needle was withdrawn.
Interventions and evaluations were carried out by the same medical staff, but the assessment was strictly standardized. The average physician time required to perform these procedures is relatively low and it has been less than that spent in fluoroscopic-guided epidural injections. Operator radiation doses were not calculated as we used a film badge and there was no personal dosimeter inside the lead apron at chest level with the operator standing ~3 feet from the gantry. The film badges were calculated every 3 months.
After the procedure, the patient was observed in the recovery room or the short stay unit for 1-2 h depending on the patient's condition; all patients were asked to report the degree of pain before injection, at 24 h, and after 2 weeks, 3, and 6 months, and it was assessed using visual analogue scale (VAS) (where 0 = no pain and 10 = the worst pain imaginable) and the patient satisfaction scale (excellent, good, poor, bad); the need for repeated injections at less than 3 months and any adverse events were also recorded. All patients were advised to return to normal daily activity without fear. A follow-up evaluation was performed by a person in the pain clinic or by a telephone interview. Two weeks after the first treatment, if the pain level was still greater than 3, then another CT-guided ESI was carried out. Patients received up to two ESIs at intervals of 2 weeks as long as their pain level was greater than 3. Further evaluations were scheduled at 2 weeks as well as at 3 and 6 months after the last ESI. A successful outcome was achieved at the time of follow-up if patients reported at least 50% overall subjective pain relief.
The sample size was calculated using the Epi Info program, version 7 (SPSS Inc., Chicago, Illinois, USA), and data were analyzed by the statistical package for social science, version 16 (SPSS Inc., Chicago, Illinois, USA). Qualitative data were presented as number and percentages, whereas quantitative data were presented as mean and SDs when parametric and as median (interquartile range) when nonparametric. The unpaired t-test, the χ2 -test, and the Mann-Whitney U-test were used to compare the two groups. P-value more than 0.05 was considered nonsignificant, whereas P-value less than 0.05 was considered significant and P-value less than 0.01 was considered highly significant.
| Results|| |
Forty patients who fulfilled the inclusion criteria were studied. There were no significant differences between the two groups with regard to patient characteristics (P > 0.05), but there was a significant difference at the disc level between the two groups (P < 0.05) [Table 1].
Patients in both groups were assessed for improvements in the pain score. A significantly lower pain score on VAS was observed in the DH group (4.3 ± 1.5, 3.2 ± 1.6) compared with the SS group (5.8 ± 2.4, 5.2 ± 1.5) in acute stages of treatment, that is after 24 h and the second-week follow-up (P < 0.05), whereas a highly significant reduction in VAS was observed in the 3- and 6-month follow-up in the DH group (2.4 ± 1.4, 1.6 ± 1.2) compared with the SS group (4.6 ± 1.7, 4.9 ± 2.4) (P < 0.01) [Figure 2].
|Figure 2: The visual analogue scale (VAS) for pain in both groups before injection, at 24 h, 2 weeks, 3, and 6 months after injection. Values are expressed as median (range) and indicate a significant reduction in VAS in the DH group compared with the SS group (P<0.01). DH, disc herniation; SS, spina l stenosis.|
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Also, the DH group showed a significantly higher number of patients (16) who were satisfied with a single injection throughout the period of the study compared with nine patients in the SS group, whereas only four patients needed two injection in the DH group compared with 11 patients in the SS group (P < 0.04). With the duration of trials, the DH group showed a higher significant reduction in the duration of trials (5 ± 3) compared with the SS group (10 ± 2) (P < 0.001). Patient satisfaction scale was more significantly increased in the DH group by about 80% compared with 15% in the SS group (P < 0.001) [Table 2].
|Table 2: The number of injections, the duration of trials, and patient satisfaction|
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Regarding adverse effects, vasovagal attack was noticed in both groups, but the incidence was more in the SS group three patients compared with one patient in the DH group), which is highly significant (P<0.669), and was treated by atropine 0.5 mg intravenously. Also, vascular puncture was reported in three patients in the SS group compared with no patients in the DH group, and was managed by redirection of the needle again till no blood was aspirated, and when real-time CT guidance with contrast did not reveal any vascular run off, then the injection of steroids and local anethestics was carried out. Only two patients in the SS group had hypotension, which was managed with 15 mg of ephedrine (P < 0.669) [Table 3].
| Discussion|| |
Pain relief obtained with ESIs often facilitates the patient's tolerance for and progression through a functionally oriented rehabilitation program. Corticosteroids have been noted to have potent anti-inflammatory properties  ; corticosteroids supposedly inhibit the neuropeptide synthesis of prostaglandin by inhibiting inflammatory mediators such as phospholipase A2 liberated from herniated and degenerated discs , , and also reduce capillary permeability  , inhibit transmission in unmyelinated C fibers, suppress inflammation, stabilize the membrane, and have some anesthetic action, which reduces sensory symptoms , . The fact that corticosteroids differ significantly in microscopic size has become an important consideration because of an awareness that the larger a particle, the greater its chances of occluding a blood vessel should the compound be inadvertently injected intravascularly. A study that analyzed the microscopic size of the corticosteroids found that methylprednisolone (Solu-Medrol) particles were relatively uniform in size, smaller than red blood cells, and densely packed and did not form too many aggregations  .
Levobupivacaine, the pure S (−)-enantiomer of bupivacaine, is a long-acting local anesthetic and analgesic. It blocks nerve conduction in sensory and motor nerves largely by interacting with voltage-sensitive sodium channels on the cell membrane, but potassium and calcium channels are also blocked; it has strongly emerged as a safer alternative than its racemic sibling bupivacaine. Levobupivacaine has been found to be as efficacious as bupivacaine, but with a superior pharmacokinetic profile: an ~13% more active substance compared with bupivacaine  .
CT fluoroscopy guidance is helpful, especially in lumbar epidural injections, because it allows precise visualization of the anatomy and the needle tip during the procedure, as it accesses the epidural space and avoids any osseous structure, even in patients with spinal stenosis or intralaminar space narrowing. The technique is fast, safe, and highly accurate in providing appropriate needle placement  .
In the present study, we were able to prove that ESIs of 40 mg methylprednisolone with 25 mg levobupivacaine 0.5% using the PIL approach for chronic lumbar spine pain under CT guidance were effective and provided better pain relief in the DH group compared with the SS group because of the correct placement of the needle in the epidural space, and the proper placement of steroids near the pathologically inflamed nerve roots.
Results of the present study are in agreement with other studies; Arden et al.  reported that ESIs under CT guidance were found to be up to 93% effective because of the correct placement of the needle in the epidural space. Benyamin et al.  reported that the efficacy of lumbar interlaminar epidural injections with fluoroscopic guidance is good for radiculitis secondary to disk herniation with local anesthetics and steroids and fair with local anesthetics only, whereas it is fair for radiculitis secondary to spinal stenosis with local anesthetics and steroids and fair for axial pain without disk herniation with local anesthetic with or without steroids.
A prospective study conducted by Candido et al.  demonstrated that as compared with conventional lumbar interlaminar epidural injections, the lateral parasagittal interlaminar epidural approach has a higher rate of contrast spread into the anterior epidural space, and the PIL lumbar approach is superior to the TF approach for placing the contrast into the anterior epidural space with reduction in fluoroscopy times and an improved spread grade. With increasing attention to the neurological injury associated with TF, the PIL approach may be more suitable for routine use. Faleiros Sousa and Gomes Colhado  concluded that the interlaminar epidural analgesic block, effective in the treatment of herniated disk, induces lombosciatalgia.
Studies have suggested that depending on the particular clinical scenario, the total dose of methylprednisolone should probably not exceed ~3 mg/kg of body weight, to prevent excessive salt and water retention. A study of methylprednisolone dosage in patients with chronic lower back pain found that a 40 mg dose is just as effective as an 80 mg dose in improving disability. The lower dose should be considered for patients who receive repeat injections  . Epidural methylprednisolone injection has less analgesic effect in patients with lumbar SS compared with HD, with less permanent effect  .
Our study revealed significant pain relief in the DH group compared with the SS group; this was demonstrated by the decrease in both VAS and analgesic consumption 2 weeks after injection and continued throughout the follow-up period (up to 6 months). VAS was 6.6 ± 0.5 before injection as against 3.2 ± 1.6 2 weeks after injection in the DH group compared with 6.9 ± 0.8 before injection and 5.2 ± 1.5 2 weeks after the injection (P<0.01) in the SS group, and analgesic consumption decreased by 60% in the DH group compared with 15% in the SS group (P < 0.01). Schaufele et al.  reported VAS score results similar to our study as there was a significant improvement in the VAS score from before injection (VAS mean 5.9) to (VAS mean 3.2) after injection.
This coincides with a meta-analysis that has reported all randomized controlled trials related to lumbar epidural steroids injections (LESIs) and showed that they were effective only in the short term (up to 6 months only), reducing the need for hospitalization and opioid analgesic requirements  . Also, a large prospective randomized controlled trial showed that conventional LESI was effective in the short term, but did not reduce the need for surgery compared with the placebo control  . Ramsin et al.  reported that interlaminar epidural injections showed a significant reduction of pain scores in patients with lumbar radiculitis when compared with no intervention and conservative management without injection therapy. However, in a randomized study on two groups of individuals with lumbar pain of radicular origin, 80 mg of methylprednisolone in 43 patients was compared with 40 mg of methylprednisolone in 41 individuals. Visible improvement was observed in 1 month in 64 cases (75%) by VAS. Both groups were compared at 2 weeks and 3 months after the epidural injection. Better results, although small, were observed in the group that received 40 mg of methylprednisolone when compared with the 80 mg group (75.6 vs. 74.4%) , .
As for the number of injections, Schaufele et al.  found that 45% of the patients were satisfied with a single injection compared with our study, wherein 80% of the patients in the DH group were satisfied with a single injection as against 45% in the SS group. (P < 0.04). Some physicians use more than one ESI at different time intervals; however, when the needle is placed in the correct position, a single injection is as effective as multiple injections, and this was in agreement with the present study  . The duration of trials in the present study was significantly decreased in the DH group (5 ± 3) compared with the SS group (10 ± 2) (P < 0.001). Similar to our study, Wagner  reported that the average physician time required to perform these procedures is relatively low and it has been equal to or less than that spent in fluoroscopic-guided epidural injections. Patient satisfaction in our study was relatively higher in the DH group (about 80% of the patients were highly satisfied compared with 15% in the SS group; P < 0.001).
Regarding adverse events, of our 40 patients, there was no incidence of dural puncture. About 10% of the cases had intravascular puncture during the placement of the needle; 15% had vasovagal attack and 10% of the cases showed hypotension in the SS group compared with only 5% of the cases in the DH group who had vasovagal attack and 5% who had an intravascular puncture (P < 0.669). In agreement with our results, Furman et al.  reported that the rate of intravascular injection was 11.2 compared with 10% in our study. Also, Aref et al.  found that the intravascular placement of the needle was 17% and vasovagal attack occurred in 16% of the cases.
| Conclusion|| |
The use of ESIs of methylprednisolone with levobupivacaine through the PIL approach with CT guidance in conjunction with a properly designed rehabilitation program played a very important role in the conservative management of patients with disc herniation compared with spinal stenosis, improving their quality of life and function.
| Acknowledgements|| |
Conflicts of interest
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3]