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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;85:479–84.
Objective
To determine patient satisfaction, relief of pain, frequency of injections, change of function, and subsequent surgical rate in patients who received epidural steroid injections (ESIs) for the diagnosis of lumbar spinal stenosis (LSS).
Design
Retrospective review conducted using a standard set of questions asked over the telephone, 6 to 36 months after the patient received an ESI.
Setting
An outpatient spine center.
Participants
One hundred forty patients at or over the age of 55 years diagnosed with LSS who received ESI(s).
Intervention
Transforaminal or caudal fluoroscopically guided ESIs with 60 to 100mg of triamcinalone in combination with local anesthetic or normal saline.
Main outcome measures
Duration and amount of pain relief, change in functional status, patient satisfaction, and surgical rate, assessed by a 5-item questionnaire.
Results
Of the 140 participants, 32% reported more than 2 months of pain relief, 39% reported less than 2 months of pain relief, and 29% reported no relief from the injection(s). Twenty percent subsequently had surgery. Fifty-three percent reported improvement in their functional abilities. Seventy-four percent where at least somewhat satisfied with ESI as a form of treatment.
Conclusions
ESI is a reasonable treatment for LSS, providing one third of our patient population with sustained relief and more than half with sustained improvement in function.
Degenerative lumbar spinal stenosis (LSS) accounts for a substantial number of patients seeking treatment for low back and lower-extremity pain. Treatment for stenosis has historically consisted of some form of conservative treatment or, in the absence of positive results from the former, surgery. Although both surgery and more conservative treatments are pervasive, only a few outcome studies have been undertaken to evaluate the effectiveness of the various interventions.
This scarcity of outcome studies on treatment for stenosis contributes to the existing uncertainty about what specific treatment is best and when it is most appropriate. In the Maine Lumbar Spine Study, stenosis patients reported better outcomes with surgery than with conservative management at 1 and 4 years,
although surgical outcomes declined somewhat over time, and outcomes of patients who had conservative treatments improved somewhat with time. Surgery also may be contraindicated in many stenotic patients because of significant comorbidities. Conservative management, therefore, remains a necessary and viable alternative for those who cannot or do not want to undergo surgery.
Epidural steroid injections (ESIs) have been used since 1952 for the treatment of radicular pain and are currently being used with increasing frequency for the treatment of stenosis, particularly in the United States.
With stenosis, mechanical compression of the nerve root(s) may result in the formation of edema as a result of microvascular injury, theoretically producing pain.
Edema formation in spinal nerve roots induced by experimental, graded compression an experimental study on the pig cauda equina with special reference to differences in effects between rapid and slow onset of compression.
Regardless of its frequent use, the ESI procedure for treatment of stenosis is controversial, and the efficacy of this treatment has not been well documented. The existing literature on ESI typically examines the procedure’s effectiveness for multiple diagnoses instead of focusing solely on its use for treatment of stenosis. Six controlled studies
Treatment of chronic low back pain and sciatica comparison of caudal epidural injections of bupivacaine and methylprednisolone with bupivacaine followed by saline.
in: Bonica J.J. Albe-Fessard D. Advances in pain research and therapy. 1. Raven Pr,
New York1976: 927-932
Treatment of chronic low back pain and sciatica comparison of caudal epidural injections of bupivacaine and methylprednisolone with bupivacaine followed by saline.
in: Bonica J.J. Albe-Fessard D. Advances in pain research and therapy. 1. Raven Pr,
New York1976: 927-932
of the 6 reported superior outcomes when comparing the use of epidural steroids with anesthetic or saline alone, but many of these studies lacked sufficient data or failed to reach statistical significance to support their conclusions.
Treatment of chronic low back pain and sciatica comparison of caudal epidural injections of bupivacaine and methylprednisolone with bupivacaine followed by saline.
in: Bonica J.J. Albe-Fessard D. Advances in pain research and therapy. 1. Raven Pr,
New York1976: 927-932
examined 37 patients with spinal stenosis who received 1 or 2 ESIs. Average subjective improvement (43%) was the same for the steroid group and for the control group at 13 to 30 months after injection. Although Cuckler
concluded that the study failed to show the efficacy of ESI for LSS, the significance of the findings is diminished by reported flaws in the methodology.
Results of uncontrolled studies of ESI for stenosis are difficult to summarize because outcome measures and follow-up periods vary considerably. Rivest et al
looked at patients’ reports of improvement 2 weeks after translaminar ESI for spinal stenosis and herniated nucleus pulposus. Of those with stenosis, 38% reported improvement at 2 weeks. Hoogmartens and Morelle
reported considerable overall pain reduction in 30 LSS patients undergoing 3 consecutive caudal ESIs. Most of their patients reported sustained relief for at least 6 months and had persistent, significant reduction in pain scores 10 months after injection, although Ciocon stated that the patients may have had unusually mild disease. Rosen et al
reviewed 40 patients retrospectively to evaluate the effect of ESI on spinal stenosis and herniated disk, with 50% of patients with radicular symptoms receiving temporary relief with translaminar steroid injection, but long-term relief occurred in less than 25% of their patients. Similar results were obtained by Simotas et al,
who reported 25% with sustained improvement from conservative treatment including aggressive epidural steroid management.
Overall, no compelling evidence exists to validate the use of ESIs for the treatment of LSS. We have concluded that most significantly absent are studies using fluoroscopically guided ESIs, which are clearly needed to ascertain the procedure’s accuracy regarding needle placement.
The present study retrospectively looked at patients who received ESIs with fluoroscopy to determine the amount and duration of relief statistics, satisfaction with the procedure, and the rate of subsequent surgery. Our main goals in undertaking this study were to determine if, in our patient population, ESIs had been useful in managing symptoms of LSS and if any characteristics were predictive of responsiveness, or lack of response, to epidural steroid placement. Our 2 outcome measures were pain relief and improvement in function.
Methods
Subjects were consecutive patients over a 3-year period who received ESIs for lumbar stenosis at an outpatient spine center. Diagnosis of stenosis was made by the authors (EGD, ARC), based on the patient history of disabling back and leg pain consistent with nerve root entrapment or neurogenic claudication. Radiographs and magnetic resonance imaging showed at least 1 level of central, lateral recess, or neuroforaminal stenosis and were read independently by the neuroradiologist and the physician performing the injection. Only persons at or over the age of 55 years were included in our study. Candidates were excluded if they had undergone lumbar spinal surgery in the past 10 years.
All participants received at least 1 or at most 7 (mean, 2.23) fluoroscopically guided
9000 C Arm; GE OEC Medical System Inc, 384 Wright Brothers Dr, Salt Lake City, UT 84116.
transforaminal or caudal injections given by 1 of 2 physicians. Patients received 60 to 100mg of triamcinolone in combination with local anesthetic or normal saline. The injection was administered at the level of most significant lumbar nerve root or thecal sac compression or caudally to some with multilevel central canal stenosis.
If patients had some lasting relief from the epidural but symptoms returned over the 3-year period, they received occasional reinjection. If patients had no relief from the first injection, another level or technique may have been tried. Patients not receiving significant relief from injections were evaluated for surgical decompression.
Prospective subjects were sent a mailing that described the study, asked for verbal consent, and invited their participation. The assessment instrument, consisting of 5 standardized questions, was also included in the mailing. Approximately 1 week after the mailing was sent, contact was made by telephone by 1 of 2 investigators. The person making the call did not meet or get involved with the care of the person she called.
After giving verbal consent, participants were first asked whether they had had surgery since the epidural(s). If they had not had surgery, they were asked the 5 questions related to the outcome of the epidurals (table 1). If they had undergone surgery since the epidurals, they were still asked about the duration of relief from the epidural (question 1) and if they would repeat the epidural (question 5). Surgical subjects were then asked 3 other questions related to the outcome of their surgery.
Table 1Outcome Assessment Instruments
Questionnaire for Nonsurgery Participants
1.
From the epidurals, did you have:
No relief, relief >2 months, relief <2 months
2.
How would you rate the overall pain relief that you have had from the epidurals?
A
Initially: Full, partial, none
B
Currently: Full, partial, none
3.
Do you think the epidurals have improved your ability to perform your daily activities?
Yes, partially, no
4.
What was your overall satisfaction with the epidurals?
Very satisfied, somewhat satisfied, very unsatisfied
5.
Would you repeat the epidurals if necessary?
Yes, no
Questionnaire for Back Surgery Participants
1.
Questions 1 and 5 as above
2.
How would you rate your pain relief from surgery?
Full, partial, none
3.
Has surgery improved your ability to perform your daily activities?
Yes, partially, no
4.
What was your overall satisfaction with surgery?
Very satisfied, somewhat satisfied, very unsatisfied
Ethics approval for the study was obtained by the internal review board of Christiana Care Health System in Wilmington, DE.
Data analysis
For questions 1 and 2A, we performed a univariate analysis to consider how question-response related to each characteristic individually and a multivariate analysis to consider the effect of the characteristics in combination. A value of P less than .05 was considered statistically significant.
For both univariate and multivariate analyses, ordinal regression, polytamous regression (when the proportional-odds assumption was invalid), or the Mantel-Haenszel test (when cell frequencies were zero) was performed.
SAS Institute Inc, 100 SAS Campus Dr, Cary, NC 27513.
Results
Two hundred forty patients met the criteria for participation. Of those, 12 declined to participate, 11 were deceased, and 68 could not be reached. This left 149 candidates. An additional 9 persons were excluded because they had undergone spine surgery in the last 4 months, making the total number of subjects 140.
Baseline characteristics
Fifty-two men and 88 women participated, with a mean age ± standard deviation of 70.9±8.7 years. Mean length of time at follow-up since the first injection was 17.23±7.24 months. The mean number of injections was 2.24±1.29. Eighty participants (57%) had multilevel stenosis. Mean symptom duration was 26.2±41.6 months.
One hundred three patients (74%) received a transforaminal and 91 (65%) a caudal epidural. Fifty-nine percent of patients received both. Twenty-five (18%) had diabetes, and 40 (29%) had a degenerative spondylolisthesis. Eleven (8%) were current smokers.
Outcomes related to epidurals
The subjects’ responses regarding duration of relief (fig 1A), amount of relief (fig 1B), current functional status (fig 1C), and satisfaction with the epidural(s) (fig 1D) are presented in figure 1. The surgical rate in 140 subjects was 20% (28 patients).
Fig 1Outcomes after ESI: (A) duration of relief, (B) amount of pain relief, (C) current functional status, and (D) satisfaction.
Seventy-four percent of nonsurgical patients stated that they would repeat the epidural if necessary, whereas 68% of surgical patients stated they would repeat the epidural if necessary.
Outcomes related to surgery
Responses regarding pain relief from surgery (fig 2A), current functional status after surgery (fig 2B), and satisfaction with surgery (fig 2C) are presented in figure 2.
Fig 2Outcomes after surgical intervention: (A) pain relief, (B) current functional status, and (C) satisfaction. Abbreviations: Sat, satisfied; Unsat, unsatisfied.
For question 1 (duration of relief), age, gender, multilevel disease, diabetes, and smoking were not statistically significant predictors of how patients would respond to epidurals (table 2). Surgery was significant (P<.001); that is, patients who went on to have subsequent surgery were less likely to have had relief with the epidurals. Number of injections was also significant (P=.006); patients who received 2 or more injections had better results than those who received only 1 injection. Multivariate results for question 1 (table 3) indicated that number of injections remained statistically significant (P=.006). Spondylolisthesis was marginally significant (P=.078). Also, although not estimable in multivariate polytamous regression, the asymptomatic P value for the Cochrane-Mantel-Haenszel test for surgery (controlling for number of injections and spondylolisthesis) was significant (P<.001).
Table 2Univariate Analysis for Question 1 (>2m/<2m/None) (N=140)
For question 2A (amount of relief initially after the injection), number of injections continued to be significant (P=.007) as did gender (P=.049), with men more likely to do better than women (table 4). Diabetes was marginally statistically significant (P=.064). In multivariate analysis (table 5), number of injections remained statistically significant (P=.002), and gender was marginally so (P=.071). Diabetes was not statistically significant (P=.12).
Table 4Univariate Analysis for Question 2A (1=Full/2=Partial/3=None): Nonsurgery Patients Only (n=112)
have shown that the majority of patients with stenosis managed conservatively do not worsen over time. Amundsen followed up with stenotic patients for 10 years and found no clinically significant deterioration in symptoms in the majority of patients. In addition, delayed surgery resulted in just as favorable outcomes as immediate surgery. Atlas
found that conservatively managed patients remained the same or showed a trend toward improvement with time. Thus, it appears that stenosis is a degenerative condition that does not necessarily symptomatically worsen with time but has periodic exacerbations and remittances.
Our data suggest that some of the patients in our population found epidurals to be helpful in managing their symptoms during these exacerbations. Thirty-two percent had more than 2 months of pain relief. In addition, at the time of contact, 45% of our patients were reporting some amount of relief and 53% sustained improvement in function at a mean of 18 months after their first injection. Varying follow-up times make comparison difficult, but 2 other studies that looked at long-term relief reported 25% with sustained improvement.
who reported 38% short-term improvement from epidurals. In the short term (<2mo in our study), 71% of our patients were reporting improvement. This discrepancy may highlight the importance of approach and documenting appropriate placement of medication by fluoroscopy. Most studies, (including Rivest’s), describe a translaminar approach. We used a transforaminal or caudal approach, both of which may allow more effective placement of medication. In contrast to the present study, most previous studies on epidurals and stenosis (with 1 exception
) did not use fluoroscopy. Without fluoroscopy, the benefit of epidurals may be underreported, because poor results may occur as a result of the steroid not reaching the epidural space and the desired nerve roots. Many studies suggest that, without fluoroscopic guidance, 40% of caudal and 30% of translaminar injections are not properly placed in the epidural space
; thus their therapeutic benefit derives only through systemic absorption.
Forty-six percent of our population was very satisfied with their treatment, and 74% were at least somewhat satisfied. As in the study by Simotas et al,
our satisfaction rates are somewhat higher than the percentages would suggest for duration of relief. This finding may represent patient satisfaction with the process of care as well as the results from the epidural.
There were no specific baseline characteristics that forecast the outcome from epidurals in our study. Age, diabetes, smoking, and multilevel disease did not predict response to the epidural. Patients with spondylolisthesis showed a trend toward less favorable results, although it was not statistically significant. In our population, men were more likely to have more than 2 months of relief, but that factor did not remain statistically significant in the multivariate analysis. Because our sample size was comparatively small (N=140), our present study could not detect relatively small differences, although others
Because we were primarily looking at outcomes from epidurals, it was beyond the scope of the present study to report extensive and long-term surgical outcomes; nonetheless, we did collect pain relief and functional status data for our surgical patients at least 4 months after surgery. Maximum benefit from surgery is attained by 3 months after surgery.
at 3 months and 1 year after surgery. Functional status was also similarly improved in our population, with 75% reporting functional gains after surgery, in line with the 81% of participants in the Atlas
Several methods limitations moderate our findings. The present study has all the inherent limitations of a retrospective study. Patients’ recall may be inaccurate and biased. There was no control population, so some of the reported benefits may be as a result of placebo effect. Further, we did not use a validated outcome tool or attempt to track other conservative interventions that may have affected outcome.
We did not have baseline measurements of severity of stenosis, but radiographic evidence of stenosis severity imperfectly correlates with severity of symptoms and nonoperative outcome.
No validated system for rating stenosis radiographically exists, and physicians are only moderately reliable in agreeing on whether patients have stenosis and are unreliable in grading the degree.
found that patients with scoliosis tended to have poorer outcomes with epidurals.
Conclusions
ESIs provided approximately one third of our patient population with more than 2 months of relief, and more than one half with improvement in function. The majority of patients were satisfied with ESIs as a form of treatment in assisting them through the more painful periods of their condition, although many required reinjection for periodic flare-ups over the 3-year period. Future research should be directed at a prospective, controlled study of epidurals, as well as at their role as part of a structured conservative management program.
Suppliers
aExposcop 7000; Ziehm International Medical System, 4181 Lathan St, Riverside, CA 92501.
b9000 C Arm; GE OEC Medical System Inc, 384 Wright Brothers Dr, Salt Lake City, UT 84116.
cSAS Institute Inc, 100 SAS Campus Dr, Cary, NC 27513.
Acknowledgements
We thank Edward Pequignot, MS, for the statistical analysis.
☆No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the author(s) or on any organization with which the author(s) is/are associated.
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