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In reply
- Martin Avellanal, G Diaz-Reganon (18 November 2008)
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Review of interlaminar approach for epiduroscopy in patients with failed back surgery syndrome
- Kevin R Fai, Mary Engleback, Jonathan Norman, Richard Griffiths (10 November 2008)
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Martin Avellanal , G Diaz-Reganon
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Re: Review of interlaminar approach for epiduroscopy in patients with failed back surgery syndrome. In reply: To the editor. We are grateful to Fai et al for their comments. Probably the design of the study could have been better and included more parameters, but we employed a system used in other works (1,2). In our study 31.6 % of the patients showed very significant improvement which was maintained in all cases 6 months later (and now we can afirm that the improvement continued one year later too). These patients had had all the treatments available, including epidurolysis, with no results. If we would not have performed an epiduroscopy, these patients (1/3) would have been submitted to spinal cord stimulation. It means that 1/3 patients had relief from a serious pain problem and they have returned to their work and normal life without implantation of spinal cord stimulation systems.Moreover, in no case the procedure made the patient worse. Therefore, we believe it to be clinically significant. In relation to the rate of complications, we had 21 % incidence of dural puncture. It is very high in comparison with others (3). These are our initial results. We think that our patients can not be compared with other series due to their high number of operations at lumbar level. On the other hand, only one patient suffered post dural puncture headache. If you want to break adhesions down and reach the nerve roots in patients with strong adhesions, dural puncture during catheter advance must be considered as a side-effect. It can probably be diminished with practice. In fact, we have reduced the incidence of dural puncture to 10 % in the last 20 procedures performed; in these cases none patient suffered headache. Fai et al consider “serious complication from the procedure” some transient neurological symtoms such as headache or hypoacusia related to injection of saline boluses. Mean duration of such “serious complications” were 10 seconds, and in no case these lasted for more than 30 seconds. These are well known transient symptoms in patiens submitted to epiduroscopy or epidurolysis, specially in patients who are not under sedation, and are directly related to the pressure of injection. We did not mention cases of visual disturbance or intravascular injection because we did not have these complications. However, we included in the discussion a paragraph related to these transient symptoms and the importance of a more accurate control of the epidural pressure in order to avoid them. As for the possible risk of shearing the epiduroscope, it was not a problem in any case. We employed an epidural needle (14 G RX COUDÉ) with special design of the tip that makes it possible to advance and withdrew the catheter without shearing it. We think epiduroscopy will find a place among the diagnostic and therapeutic tools in patients with chronic low back pain with or without radiculopathy, and especially in patients with failed back surgery syndrome. We have described a new method for performing epiduroscopy, which allows interlaminar approach. It requires training and practice. In fact, we have improved on our personal results, now reaching 40% of very significant improvement in the last series with a very low incidence of side-effects. M. Avellanal and G. Diaz-Reganon. References. 1.- Geurts JW, Kallewaard J-W, Richardson J, Groen GJ. Targeted methylprednisolone acetae/hyaluronidase/clonidine injection after diagnostic epiduroscopy for chronic sciatica: a prospective 1-year follow- up study. Reg Anesth Pain Med 2002; 27: 343-52. 2.- Dashfield AK, Taylor MD, Cleaver JS, Farrow D. Comparison of caudal steroid with with targeted steorid placement during spinal endoscopy for chronic sciatica: a prospective, randomized, double blind trial. Br J Anaesth 2005; 94: 514-9. 3.- Igarashi T, Hirabayashi Y, Seo N, Saitoh K, Fukuda H, Suzuki H. Lysis of adhesions and epidural injection of steroid/local anaesthetic during epiduroscopy potentially alleviate low back and leg pain in elderly patients with lumbar spinal stenosis. B J Anaesth 2004; 93: 181-7 Conflict of Interest:None declared |
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Kevin R Fai, Pain Fellow Pembury Pain Clinic, Mary Engleback, Jonathan Norman, Richard Griffiths
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To the editor, We read with interest the article by Avellanal and Diaz-Reganon. We acknowledge that they have demonstrated that the interlaminar approach for epiduroscopy is possible. However we would argue with their conclusions that it's diagnostic efficacy was clear due to flaws in the design of the study and their worryingly high rate of complications. As a study, there were small numbers involved, a short duration of follow up for a chronic condition, wide variations in pre-procedure management, no blinding and no attempt to provide control subjects. Furthermore there appears to be no attempt made to adhere to the core outcome measures as detailed in the IMMPACT (Initiative on Methods, Measurement and Pain Assessment in Clinical Trials)recommendations (2) making acceptance of the findings more difficult. We have reservations over a technique which offers a 31.6% chance of no improvement and a 10% chance of making symptoms worse. Even in the group who showed improvement 7/13 of this group only had a one to two point improvement in their VAS (visual analogue scale). Is such a small drop in VAS clinically significant? Possibly if the authors could have demonstrated a reduction in other core outcome measures such as physical and emotional functioning or drug use reduction. Unfortunately they did not. In addition, they describe what we feel is an unacceptably high rate of complications. The authors describe 4/19 (21%)patients suffered dural puncture. This does not compare favourably in comparison with Igarashi et al (3) who had 1/58 (1.7%)patients suffer a dural puncture. A further 4/19 patients suffered transient neurological symptoms of headache or hypoacusia meaning that 8/19 (42%)patients had sufferred a serious complication from the procedure. At no point in their study to they mention other previously described complications which were felt to not be uncommon. This includes intravascular injection (4) and visual disturbance (5). Collectively we also had other reservations after reading the description of the technique. Using a solid 14G Tuohey needle to introduce the epiduroscope raises 2 problems. Firstly how were they able to safely secure it's position within the epidural space? Secondly did they experience problems with shearing of the epiduroscope when they advanced and withdrew the catheter through the needle or when they rotated the Tuohey needle itself to help steer the epiduroscope? These are problems which one would not anticipate using the previously described route via a soft tipped introducer placed through the sacral hiatus over a guidewire. In conclusion we felt that this approach for epiduroscopy whilst physically possible, was not clinically appropriate on the grounds of weak evidence which shows low success rates and high complication rates. This paper is not going to alter the NICE guidelines (6) which states that there is inadequate safety and efficacy evidence to support epiduroscopy other than for research and audit. This stance is further supported by the findings that targeted placement of epidural steroid is no better than an untargeted caudal epidural injection which is associated with a lower risk of complication (7). Kevin R Fai, Mary Engleback, Jonathan B Norman, Richard Griffiths. References: 1. Avellanal M, Diaz-Reganon G. Interlaminar approach for epiduroscopy in patients with failed back surgery syndrome. BJA 2008; 101(2): 244-249. 2. Dworkin RH, Turk DC et al. Core outcome measures for chronic pain trials: IMMPACT recommendations. PAIN 113 (2005): 9-19. 3. Igarashi T, Hirabashi Y et al. Lysis of adhesions and epidural injection of steroid/local anaesthetic during epiduroscopy potentially alleviate low back and leg pain in elderly patients with lumbar spinal stenosis. BJA 2004; 93(2): 181-7. 4. Heavener JE, Wyatt DE et al. Lumbosacral epiduroscopy complicated by intravascular injection. Anaesthesiology 2007; 107: 347-350. 5. Gill JB, Heavener JE. Visual impairment following epidural fluid injections and epiduroscopy. A review. Pain Medicine Vol 6, number 5 (2005). 6. NICE (National Institute for Clinical Excellence)- Endoscopic division of epidural adhesions - Issed Sept 2004. 7. Dashfield AK, Taylor MB et al. Comparison of caudal steroid epidural with targetted steroid placement during spinal endoscopy for chronic sciatica: a prospective, randomized, double blind trial. BJA 2005; 94(4): 514-519. Conflict of Interest:None declared |
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