Case Study by William Ackerman , MD ; Mahmood Ahmad , MD
Is Lumbar Steroid Injection Efficacy Dependent on the Type of Disc Herniation ?
Introduction
Injections of steroids are an important adjunct for the management of lumbar radicular pain . More practitioners in Arkansas ( anesthesiologists , physiatrists , pain specialists , interventional radiologists , neurosurgeons , CRNAs , and orthopedic surgeons ) are currently performing these injections , and with increasing frequency . However , to date , there is no consensus on the most efficacious method of steroid injection to be utilized for a specific lumbar radicular discomfort . When mechanical stress is placed on the lumbar spine , a lumbar disc may bulge or tear . Following a disc injury , the displaced disc may compress a spinal nerve or cause chemical leakage from an injured disc , which may empty prostaglandins , cytokines , chemokines , etc ., into the epidural space and can cause inflammatory and radicular pain . 1 For pain reduction , it has been reported that corticosteroids may be administered directly into the epidural , intramuscular spaces , or given orally . 2-6 Epidural steroid injection therapy for lumbar radicular pain reduction may be accomplished by one of three methods : caudal ( C ), interlaminar ( IL ), or transforaminal ( TF ). 7 , 8 However , the methods used for epidural injections vary with different practitioners , and no standard for the performance of this procedure has been defined . Unfortunately , some patients will go from one pain treatment center to another and receive multiple steroid injections with only minimal relief . The way to achieve effective epidural steroid injection therapy is to choose the proper epidural steroid technique for the specific discogenic pathology .
Disc herniations are classified according to their nucleus pulposus shape . The disc material , which comes from the pulpous nucleus , is displaced beyond the intervertebral limits when a herniation occurs . It may take one of three different shapes : protrusion , extrusion , or sequestration . The purpose of this study was to compare the analgesic efficacy of steroid injections in the three different pathologic categories of lumbar disc herniations .
Methods
This investigation , which was done following University Institutional Review Board approval , is a randomized trial of patients between the ages of 21 and 60 with lumbar radicular pain who were treated within seven days of his / her pain onset . Following signed , informed consent , 300 patients were randomly assigned to one of four groups of 25 to receive dexamethasone , 10 mg ( 1ml ) with two ml of normal saline and 1 ml of iohexol contrast as follows : Group I , lumbar epidural steroid injections ( LESI ); Group II , transforaminal steroid injections ( TFESI ); Group III , caudal epidural steroid injections ; and Group IV , para spinous muscle injections ( PMI ). The objective of this study was to assess radicular pain relief efficacy following lumbar epidural , caudal , transforaminal , and intramuscular steroid injection therapy in patients with one of three degrees of lumbar disc herniations with single-lower-extremity radiculitis . Each injection was done with fluoroscopic needle guidance using a 22-gauge Tuohy needle . The primary outcome of this study was a statistically significant reduction in a patient ’ s pain intensity using a 10-point ( 0 = no pain and 10 = severe pain ) numerical rating scale . Statistical analysis was done with P ≤ 0.05 necessary to reject the null hypothesis . Patient data were encoded to protect each individual ’ s identity . A P value ≤ 0.05 was considered statistically significant .
Results
A total of 300 patients were enrolled , completed this study , and were analyzed in the groups in which they were allocated . No patient was included in this study who had prior lumbar spine surgery , previous epidural injections , or oral or intramuscular steroid injections . There were no significant demographic differences between the groups of patients . Limitations of this study include the lack of a placebo control group and the absence of a long-term follow-up . The results of this investigation are in Tables 1-3 .
Conclusion
The results of this study established that the pathologic grouping of the lumbar disc herniation affected the degree of analgesic efficacy with respect to the manner of the steroid injection administered . In patients with sequestered disc herniations ( Table 3 ), transforaminal steroid injections were more efficacious when compared to intramuscular , caudal , and lumbar epidural steroid injections . Sciatica in patients with disk disease was long ascribed to pressure put on the sciatic nerve root by a herniated disk . However , a role for chemical factors acting in conjunction with a chemical insult is currently suggested by a number of clinical observations . 9 The intervertebral disk is immunogenic , and mediators for inflammation have been identified within intervertebral disk tissue . A current pathophysiological theory now incriminates proinflammatory substances secreted by the nucleus pulposus as a cause of nerve root pain . Tumor necrosis factor-alpha ( TNF-alpha ) is the main biochemical potentially responsible for radicular pain . Even after a negative screening , clinicians should maintain a high index of suspicion of CF . The terminology related to CFNBS is confusing and clinicians should work
270 • The Journal of the Arkansas Medical Society www . ArkMed . org