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Pain Management Center of Paducah Paducah, KY 42003
We read with great interest the article by Fredman et al. (1) titled "Epidural steroids for treating ‘failed back surgery syndrome:’ is fluoroscopy really necessary?" This well designed and well conducted study described the implications appropriately, but it did not draw the conclusion that fluoroscopy is medically necessary to perform epidural steroids in the treatment of "failed back surgery syndrome." As they correctly point out, despite accurate placement, the depot-steroid solution will spread to reach the level of pathology in only 26% of cases. If one considers this as the average delivery, and with an average success rate of 60% for epidural steroid injection(s), this would translate into a 16% success rate. However, if one believes that the cardinal site of pathology is considered to be in the ventral epidural space, the results look even more disappointing when using a blind epidural injection (2,3).
Several approaches available to access the lumbosacral epidural space are caudal, interlaminar (lumbar), and transforaminal (nerve root or selective epidural injections) (2,3). As stated by the authors (1), the interlaminar approach for lumbar epidural has been perceived as advantageous, because the needle is directed more closely to the assumed site of pathology, facilitating the injectate’s delivery directly to its target. However, when using a blind interlaminar technique, one may erroneously miss the targeted interspace by one or two levels. The preferential cranial flow of solutions in the epidural space necessitates the needle’s position one level below the site of suspected pathology, and the epidural needle placement may significantly deviate toward the nondependent side, thus negating the presumed benefits (4–9). Other potential difficulties encountered with lumbar epidural injections include congenital abnormalities, postsurgical spine as described, and target specific placement of injectate at L5/S1 (10). Hence, transforaminal epidural injections have been considered the most advantageous in reaching the cardinal site of the pathology under direct fluoroscopic visualization with an extremely low dose of steroids. Based on this report (1) and others in the literature (4–9), without the use of fluoroscopy and epidurography, additional risks can be foreseen with epidural steroid injections because of the increased potential for dural puncture, subarachnoid injection, and intravascular injections with associated complications. Performing a procedure that only has the effectiveness of 16% based on the present data (1) is definitely not a cost-effective procedure. However, whether fluoroscopy and epidurography add any risks is an important question. Radiation exposure is minimal in experienced hands, has a low risk of allergic reaction, and is minimized and almost entirely eliminated by using low volume, nonionic contrast media. At least in the United States, the additional cost of the procedure with fluoroscopy should be immaterial in an ambulatory surgery setting at the present time, because surgery centers are paid for the facility based on global charges regardless of whether fluoroscopy was utilized. With new regulations scheduled to be implemented in hospital outpatient departments, the same global structure will be used with no extra cost for using fluoroscopy and epidurography. In fact, there will be tremendous cost savings by insuring that the epidural space has in fact been reached, thereby reducing failures by as much as 50% to 60% by avoiding misinjection.
References
Department of Anesthesiology and Critical Care Meir Hospital Kfar Sava, Israel
Although it seems that Manchikanti et al. support the use of fluoroscopy, we disagree with the conclusion that fluoroscopy is medically necessary in all cases of "failed back surgery syndrome" (FBSS). Furthermore, in our opinion, they do not provide convincing evidence to support their preference.
Manchikanti et al. criticize the fact that we have not "drawn the conclusion that fluoroscopy is medically necessary to perform epidural steroids in the treatment of [FBSS]." However, our data do not support such an emphatic conclusion. Rather, as stated in our original manuscript, in patients who have undergone surgical "procedures associated with extensive tissue trauma or in which the posterior spinous processes are removed, fluoroscopy may ensure more accurate epidural space identification." Thus, we suggest that "the surgical records may be vital when analyzing the cost-benefit of fluoroscopic guidance."
Manchikanti et al. conclude that, in the absence of fluoroscopy, epidural steroid administration would be associated with a "16% success rate." However, our study demonstrates that simple mathematical proportions are not reliable when predicting the success rate of epidural steroid placement in FBSS. Although blind needle placement was accurate in 47% of patients, spread of contrast medium within the epidural space reached the level of pathology in only 26% of patients. Because, in FBSS, the limited spread of contrast medium (or depot-steroids) is likely caused by surgically induced adhesions, in our opinion, it is doubtful that fluoroscopy would significantly improve target tissue penetration.
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