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Neurology IndiaOfficial Publication of the Neurological Society of India

Mar-Apr 2010 / Vol 58 / Issue 2

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248 Neurology India | Mar-Apr 2010 | Vol 58 | Issue 2

Original Article

Transforaminal epidural steroid injection via a preganglionic approach for lumbar spinal stenosis and lumbar discogenic pain with radiculopathy

Serdar Kabatas, Tufan Cansever, Cem Yilmaz, Ozgen Ilgaz Kocyigit1, Evrim Coskun2, Emre Demircay3, Aykan Akar, Hakan Caner

Departments of Neurosurgery, 1Anesthesiology, 2Physical Medicine and Rehabilitation, and 3Orthopedics, Baskent University, Ankara, Turkey

Introduction

Common conservative medical treatments for low back pain (LBP) and radiculopathy include oral medications,

AbstractBackground: Epidural steroid injection (ESIs) is one of the treatment modalities for chronic low back pain (CLBP) with various degrees of success. Aim: We analyzed the efficacy of fluoroscopically guided transforaminal epidural steroid injections (TFESIs) via a preganglionic approach in patients with foraminal stenosis due to lumbar spinal stenosis and lumbar discogenic pain with radiculopathy. Materials and Methods: We analyzed the data of 40 patients (February 2008 and April 2009) with the diagnosis of CLBP and treated by fluoroscopically guided TFESIs via a preganglionic approach. Patients were followed-up at one month (short term), six months (midterm) and one year (long term) after injections. Follow-up data collection included the Visual Numeric Pain Scale (VNS) and North American Spine Society (NASS) patient satisfaction scores. Results: The mean age of the patients was 59.87 ± 15.06 years (range 30 – 89 years, 25 women). Average follow-up period was 9.22 ± 3.56 months. Statistically significant differences were observed between the pre-procedure and post-procedure VNSs (P < 0.01, Pearson Correlation Test). Improvements in VNS scores were correlated with improvements in the NASS scores. When the VNS scores were evaluated with respect to the age of patient, level numbers, gender, pre-procedure symptom duration and pre-procedure VNS, no significant differences were found (P < 0.05, linear regression test). At short term evaluation in post treatment (one month), 77.78 % of patients were found to have a successful outcome and 22.22 % were deemed failures. Overall patient satisfaction was 67.23 % in the midterm period. Additionally, 54.83 % of patients (N/n: 15/8) had a successful long-term outcome at a follow-up of one year. Conclusion: Our data suggest that fluoroscopically guided TFESIs via a preganglionic approach, in patients with foraminal stenosis due to lumbar spinal stenosis and lumbar discogenic pain with radiculopathy, has effective outcome and patients responding to injection have significantly lower post-injection pain scores.

Key words: Chronic low back pain, effective outcome, lumbar spinal stenosis, preganglionic, radiculopathy, transforaminal epidural steroid injection

exercise therapies, back posture training, lifestyle modifications, and epidural steroid injections (ESIs) [1-3] First advocated in 1952 by Robecchi and Capra, lumbar ESI has become a widely performed conservative

Address for correspondence:Dr. Serdar Kabatas, Department of Neurosurgery, Baskent University Istanbul Hospital, Oymaci Sokak No:7, 34662 Altunizade/ Istanbul/ Turkey.E-mail: kabatasserdar@hotmail.com

PMID: *** DOI: 10.4103/0028-3886.63807

249Neurology India | Mar-Apr 2010 | Vol 58 | Issue 2

therapeutic modality in patients with LBP.[4] Steroid injections may be delivered to the epidural space via a percutaneous caudal, interlaminar, or transforaminal approach, and the reported success rates ranged from 20 to 100%, with an average of 67%.[1] Compared with an interlaminar or caudal ESI, a transforaminal epidural steroid injection (TFESI) provides minimal risk of dural puncture, better delivery of medication to the site of radiculopathy, and increased distribution of the drung

into the ventral epidural space.[5-7] TFESI can be given via a ganglionic approach or a preganglionic approach. Nserve root compression can be due to either subarticular or paracentral disk herniation, or central canal and/or lateral recess stenosis supra-adjacent to the intervertebral

disk. There is no clear-cut consensus regarding the optimal injection site of performing TFESI.[7] Further, Lee et al. evaluated the effectiveness of TFESI via a preganglionic approach in patients with lumbo-sacral radiculopathy in whom the nerve-root compression was supra-adjacent to the intervertbral disk,[7,8] and reported effective treatment outcomes with rare post-procedure complications. We report the effectiveness of preganglionic TFESI approach in patients with LBP due to either the lumbosacral radiculopathy or stenosis of the lumbosacral vertebrae.

Materials and Methods

The TFESI procedure was performed by the same surgeon (S.K.) in all the 40 patients seen between February 2008 and April 2009. Patient medical charts were reviewed for the diagnosis, age at onset of symptoms, duration of symptoms prior to injection, findings on magnetic resonance imaging (MRI), injection levels, and subsequent surgical procedures. Informed consent was obtained and strict patient confidentiality was maintained.

Patients were all of Caucasian lineage and the age ranged from 30 to 89 years old (mean: 59.87 ± 14.29 years). Among them, 25 were female (62.5 %). Symptom duration ranged between 12 and 300 months (mean: 76.31 ± 65.74 months) and patient VNS scores ranged between 10 and 8 before preganglionic TFESI (mean: 9.00 ± 0.68). The selection criteria for inclusion were: 1. sustaining radicular pain for more than three months in duration; 2. faukyre ifconservative treatment; 3. definitive evidence of nerve root compression with either subarticular or paracentral disk herniation or central canal and/or lateral recess stenosis at the supraadjacent intervertebral disk based on physical examination and magnetic resonance imaging (MRI). Patients with previous spinal surgery and/or ESIs were excluded. Single level TFESI was given in 28 patients (n=13 at L5-S1, n=13 at L4-L5, n=2 at L3-L4), double-level TFESI in 11 (n=8 at L4-L5 and L5-S1, n=3 at L3-L4 and L4-L5) and triple-level TFESI

in only 1 patient (at L3-L4, L4-L5, L5-S1). Descriptive statistics of the patients are shown in Table 1. All the patients received at least one fluoroscopically guided TFESI. Average follow-up period was 9.22 ± 3.56 months.

The procedureTFESIs were performed in the operation theatre

equipped with a planar fluoroscope (SiemensTM, Münich, Germany) while the patients were prone.

After sterile preparation, draping, and local anesthesia with one per cent lidocaine, a 9-cm long, 21-gauge spinal needle (StimuquikTM [insulated peripheral nerve block needle]; Arrow International, PA, USA) was advanced towards the involved neural foramen under fluoroscopic guidance. The needle position was tracked via fluoroscopy, and 1 mL of contrast material (Omnipaque 300TM [iohexol, 300 mg iodine per milliliter]; Amersham Health, Princeton, NJ) was injected to confirm

epidural flow and to avoid intravascular, intradural, or soft-tissue infiltration. Upon confirmation of reaching the intended injection site, posteroanterior and oblique spot radiographs were obtained to document distribution of the contrast material. Lee et al.[8] described that for the preganglionic approach, the landmark for needle insertion was slightly lateral to the pars interarticularis on the oblique view, and at the neural foramen near the nerve root impingement site at the supra adjacent disk level on the posteroanterior view [Figures 1 a - d]. Then 40 mg (1 mL) of methylprednisolone acetate suspension [Depomedrol TM Eczacibasi Ilac San., Luleburgaz, Kirklareli] was injected (~1 min), followed by 0.5 mL of bupivacaine HCl (Marcaine Spinal 0.5% Heavy TM; AstraZeneca, Istanbul).

Table 1: Descriptive statistics of the patients

N Minimum Maximum Mean Std. deviation

Age 40 28 89 59,88 15,06Follow-up month)

40 4 14 9,23 3,56

Duration symptoms (month)

40 12 300 77,85 65,01

VNS pre-op 40 8 10 9,00 0,68VNS early post-op

40 1 5 1,55 0,78

VNS 1st month 40 1 6 2,00 0,98VNS 6th month 40 2 6 2,95 1,13VNS 1st year 15 2 7 4,07 1,62NASS early post-op

40 1 3 1,10 0,379

NASS 1st month 40 1 3 1,10 0,379NASS 6th month 40 1 4 1,65 0,736NASS 1st year 15 1 4 2,20 0,775Level Number 1 level

2 levels3 levels

28111

Gender MaleFemale

2515

Kabatas, et al.: Transforaminal epidural steroid injection via a preganglionic approach

250 Neurology India | Mar-Apr 2010 | Vol 58 | Issue 2

Follow-up and clinical evaluationThe Visual Numeric Pain Scale (VNS) and North American Spine Society (NASS) patient satisfaction questionnaire were used to evaluate the therapeutic efficacy of TFESIs [Table 2].[1,9] Patients were evaluated before the procedure and at one week after the procedure. Those who responded favorably to TFESIs were then placed in a spine rehabilitation program for four to six weeks to maximize the functional gains. Those who did not respond or responded partially were offered either surgery or physical therapy.

VNS (0-10, 0 indicates no pain, 10 refers to the most severe pain) was recorded at the first clinical examination prior to TFESI. Patients were asked to the worst level of pain prior to, soon after, and one week after the injections. Patient outcomes were assessed one month after the

TFESIs (short term) by an anesthesiologist (O.I.K) who was blinded to the pre-injection scores. The evaluator used VNS and NASS patient satisfaction questionnaire to assess the patient’s own assessment with regard to the degree of improvement. Patients were then re-evaluated over the phone by a blinded independent observer (E.E) at six months and one year. A reduction in the VNS of more than 50% after the injection and with NASS score of 1 and 2 were classified as successful treatment, and a reduction in the VNS of less than 50% after the injection and with NASS score of 3 and 4 were classified as failed treatment. Patients who had subsequent surgery after injection were also deemed to have failed treatment.

Statistical analysisData were analyzed by SPSS version 13.0 software. The level of correlation between the pre-procedure and follow-up VNS and NASS scores were determined using Pearson Correlation test, with P < 0.05 with 95% confidence intervals considered statistically significant. The effects of the variables (age, gender, symptom duration, level number and pre-op VNS) to the results were analyzed using linear regression test, with P < 0.01 with 99% confidence intervals considered statistically significant.

Results

None of the patients experienced any complications, and all the patients completed the follow-up visits. The mean pre-procedure, post-procedure, one month, six months and one year post-procedure VNSs (mean±SEM) were 9.00 ± 0.68, 1.55 ± 0.78, 2.00 ± 0.98, 2.95 ± 1.13, and 4.07 ± 1.62, respectively. Significant differences were observed between the pre-procedure and post-procedure VNSs (P ﹥ 0.01, Pearson Correlation Test). Subsequent analysis [Table 3] revealed that VNSs at one month and one year post-procedure were correlated with each other (P=0.004). Correlation in NASS between post-procedure and one year post-procedure (P=0.008), and correlation in NASS between one month and one year post-procedure (P=0.008) were also determined. Additionally, correlation in NASS between six months and one year post-procedure (P=0.003) were confirmed statistically. These was consistent and sustainable clinical improvement after TFESI over the 12 months period when NASS progressively decreased.

Improvements in VNSs were correlated with improvements in NASSs (P < 0.05, linear regression test). There was no significant difference in VNS between post-procedure and one month (P=0.067), six months (P=0.978) and one year post-procedure (P=0.711), respectively. There was no significant difference in VNS between one month and six months (P=0.478) or one year post-

Table 2: North American Spine Society (NASS) patient satisfaction questionnaire[1,9]

Score

Epidural steroid met my expectationI improved less than I had hoped, but I would undergo the same procedure again for the same resultEpidural steroids helped, but I would not undergo the same procedure for same resultI am the same or worse than before epidural steroids

Kabatas, et al.: Transforaminal epidural steroid injection via a preganglionic approach

Figure 1: Radiographs of 41-year-old woman with radiating pain to left buttock and lower leg in the L5 dermatome. MRI (not shown) revealed left paracentral L4-5 disk herniation with compression of left L5 nerve root. TFESI with preganglionic approach was performed at L4-5 neural

foramen. Posteroanterior spot radiographs show contrast material has spread to L4-5 disk through the epidural space (a, b), oblique spot

radiographs show needle tip in posterior aspect of the L4-5 neural foramen (c,d)

a

c d

b

251Neurology India | Mar-Apr 2010 | Vol 58 | Issue 2

procedure (P=0.465). These comparisons indicated that the therapeutic benefits of TFESIs occured immediately by the injection, and the beneficial effects of TFESIs are sustainable over twelve months. However, there was a significant difference in VNS between six months post-procedure and one year post-procedure (P=0.001, [Table 4]), suggesting there could be loss of therapeutic benefit over six months after the TFESI procedures. Although the one year post-procedure VNSs still remained statistically similar to immediate post-op VNS.

Further, when the VNS and NASS were evaluated with respect to the age of the patients, level numbers, gender, pre-procedure symptom duration and pre-procedure VNS, no significant differences were found [Table 4]. A reduction by 50% or more in VNS and NASS scores at short-term (one month) follow-up was 77.8% (N/n: 40/31); at mid-term (six months) follow-up it was 67.2% (N/n: 40/27) and at long-term (twelve months) follow-up it was 54.8%.

Discussion

The efficacy, both short and long-term, of fluoroscopic TFESI in patients with radicular symptoms from lumbar disk herniation and also in patients with radicular pain from lumbar spinal stenosis has been

well documented.[4.10,11]. However, ESI performed without fluoroscopic guidance is likely to miss the perceived target area 30 to 40 % of the time.[1,10] Nevertheless, failure to institute a specific treatment modality in a specific population of patients may dilute or inflate the treatment efficacy rates. Lutz et al. reported in an uncontrolled prospective study the efficacy (75.4%) of fluoroscopically guided TFESI in 69 select patients with radiologically confirmed lumbar radiculopathy due to herniated nucleus pulposus.[12] In some of the studies the efficacy of ESI was short lasting. [13,14,15] However, our study suggests that the efficacy of TFESI can be sustained and long lasting, 67% efficacy at 6 months and 55% efficacy at one year. Our results are similar to the observations in the study by Jeong et al.[7] In their study the efficacy of TFESI was sustained beyond six months in 60% of patients.

TFESIs via a preganglionic approach provides a shorter delivery route and also allows delivery of more medicine at the site of target.[7,16,17] Ganglionic approach has its limitations such as a relatively long injection route and limited space to accommodate the injectant. The preganglionic approach may be considered as an alternative to the ganglionic approach if the needle tip cannot be advanced adjacent to the neural foramen; or adequate amount of the drug cannot be injected into the epidural space through the neural foramen due to severe

Table 4: P values of the variables after the evaluation of the effects of the variables (age, gender, symptom duration, level number and pre-op VNS) to the results using linear regression test (P is significant at the level less than 0.05).

Age Gender Symptom duration

Level number

VNS pre-op

VNS early post-op

VNS1st month

VNS6th month

VNS early post-op 0,076 0,304 0,057 0,082 0,890 – – –VNS 1st month 0,058 0,193 0,138 0,182 0,574 0,067 – –VNS 6th month 0,878 0,598 0,613 0,428 0,407 0,978 0,478 –VNS 1th year 0,589 0,614 0,677 0,230 0,366 0,711 0,465 0,001NASS 1th month 0,803 0,513 0,709 0,384 0,151 0,893 – –NASS 6th month 0,213 0,145 0,587 0,056 0,922 0,491 0,670 –NASS 1th year 0,498 0,582 0,844 0,463 0,816 0,396 0,479 0,754

VNS - Visual numeric pain scale; NASS - North American Spine Society

Table 3: Pearson correlation test was performed to correlate the pre-treatment and post-treatment and follow-up VNS and post-op NASS of the patients. .

VNS pre-op VNS post-op VNS 1st month VNS 6th month VNS 1st year

VNS pre-op , 0,768 0,639 0,304 0,990VNS post-op 0,768 , 0,000 0,000 0,000VNS 1st month 0,639 0,000 , 0,000 0,004VNS 6th month 0,304 0,000 0,000 , 0,000VNS 1th year 0,990 0,000 0,004 0,000 ,

NASS post-op NASS 1st month NASS 6th month NASS 1st year

NASS post-op , , 0,000 0,008NASS 1st month , , 0,000 0,008NASS 6th month 0,000 0,000 , 0,003NASS 1th year 0,008 0,008 0,003 ,

VNS - Visual numeric pain scale; NASS - North American Spine Society; P > 0.01 showed that the groups differ from each other. The correlation of the post-op VNS and NASS can be seen clearly (Correlation is significant at the 0.01 level (2-tailed))

Kabatas, et al.: Transforaminal epidural steroid injection via a preganglionic approach

252 Neurology India | Mar-Apr 2010 | Vol 58 | Issue 2

neural foraminal stenosis. Another advantage of the preganglionic approach is that the injectant distributes

predominantly in the epidural space at the disk level. Our results were consistent with those of previous studies.[7, 8] In our study some patients did not respond favorably to TFESIs, there may be several possible reasons. One of the reason could be that the patients might not have adhered strictly to the spine rehabilitation program.

In our study, symptom duration and other variables had no significant effect on the therapeutic outcome in all the follow-up evaluations. Pain perception can be measured by VNS and the quality of life by NASS. In our study there was good correlation between NASS and VNS scores. The validity and reliability of the VNS and NASS scales has been well documented and thus justify the use of these scales in assessing the TFESI efficacy.[1,10] Furthermore, these scales have been the standard tools in determining the outcomes in other ESI studies, and are clinically relevant and are sensitive for assessing clinical significance.[4,9]

The limitations of this study are those inherent to any retrospective study and include selection bias and lack of a control group. This study focuses on the therapeutic efficacy of TFESI via a preganglionic approach in a selected group of patients. Additionally, the number of patients included for long-term evaluation was greatly limited by the fact that most patients are yet to complete the program. However, the midterm follow-up was sufficient to evaluate the therapeutic effect of TFESI.

Acknowledgment

We thank Dou Yu, MD, PhD (the Spinal Cord Injury and Neural Stem Cell Biology Laboratory, Brigham and Women’s Hospital/Harvard Medical School, Boston, MA) for his suggestions in the preparation of this manuscript.

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Accepted on 23-10-2009Source of Support: Nil, Conflict of Interest: None declared.

Kabatas, et al.: Transforaminal epidural steroid injection via a preganglionic approach