To the Editor:

I am pleased to respond to the questions posed by Dr.Scher. In our study, a number of patients were excluded so that the study groups would be more homogeneous. Clinically, these patients were not excluded from being treated with spinal steroid injections; they just were not reported in the paper. Many of the patients who did not fit our entry criteria still had favorable responses from injection. Dr. Scher's calculations are correct as to the volume of steroid preparation given and, yes, a local anesthetic was also administered.

As to Dr. Scher's comments regarding complications, I would agree that the probability of an inadvertent dural puncture is less with the caudal approach, as it also is with the transforaminal approach, when compared to the translaminar approach used in this study. The risk of infection is remote regardless of the approach, in my opinion, and I (and my partners) have never seen one.

I currently recommend the transforaminal approach for epidural steroid injections when flouroscopy is available. This is especially true for patients with a far lateral disc herniation. My anecdotal experience with the caudal approach has been less favorable, especially when the disc herniations, or stenosis, are above L5-S1. However, my opinion is that favorable results are probably more related to the experience of the physician performing the injection than it is to the approach.

Dr. Scher also notes his experience with patients who only had short term benefit from injections. Unlike Dr. Scher's experience with patients who have had a sequestered disc herniation, those in my study generally did well. These patients often had the most severe pain and usually required short term narcotic pain medication in addition to the steroid injection. Although not part my study, I concur with Dr. Scher that patients with recurrent disc herniation or stenosis have a less predictable long term response to epidural steroid injections.

Sincerely, Glenn Buttermann, MD

The Editor:

I read with great interest the article “Treatment of Lumbar Disc Herniation: Epidural Steroid Injection Compared with Discectomy ” by Buttermann, and I have several questions and comments.

In the Material and Methods, why were the following patients excluded - those older than 70 years, those with a pars defect at the level of disc herniation, or a far lateral disc herniation, or multilevel disc herniations and recurrent disc herniations? The dose of steroid (betamethasone) used was 10-15 mg. The usual dose would be 6 mg per ml, was this on average a 2 ml injection? Was the volume further increased with saline and was local anaesthetic added?

In discussing complications in the Results, Buttermann reported a 4% incidence (2 of out of 50 patients) who had a dural puncture. I have personally performed caudal epidural steroid infiltrations (1) for some 20 years for clinically diagnosed neurogenic leg pain of spinal origin. The advantages of a caudal injection site as opposed to a lumbar epidural is that the complication rate is lower, it may be readily performed as an outpatient procedure and the outcome is comparable. Based on more than 2500 randomised cases I was interested to see that my experience with this technique tallied with the results achieved by Dr Buttermann in his well-constructed study.

I am a consultant orthopaedic surgeon in private practice. Patients usually present 1-2 months after onset of symptoms. My indications for recommending caudal epidural infiltration are leg pain usually accompanied by objective findings. These physical signs may be a positive sciatic nerve or femoral nerve stretch test, focal signs including motor fall-out (but motor strength not less than grade 3/5) and diminished tendon reflexes. In older patients where degenerative spinal stenosis was the provisional diagnosis, there is usually a paucity of objective signs. The epidural is usually performed as an out-patient procedure. All patients have preliminary plain lumbar spine x-rays. the patient. Fewer than 10% of the patients have had preliminary MR Imaging, this group would mostly have come for a second opinion. A 30 ml solution made up of 5 ml steroid (betamethasone 30 mg), local anaesthetic up to 5 ml 1% lignocaine (in the older more frail patients 2 ml is used) and normal saline to make up the volume. This is administered with a 3.5 inch spinal needle (20 gauge ) introduced via the sacral hiatus. The procedure takes a few minutes. Afterwards the patient is encouraged to have a cup of tea and may invariably go home within ten minutes. Complications have been infrequent and included 2 dural taps, probably due to an abberrant sac. In these instances the spinal needle was withdrawn and a shorter one used. One patient had transient paralysis of the lower intercostal nerves and lower limb paresis with loss of bladder sensation. He was brought to a semi reclining position and recovered spontaneously over 1-2 hours as the local anaesthetic wore off. Infrequently patients (less than ten cases overall) have experienced transient perineal numbness with weakness of one or both legs such that they had to wait a couple of hours before being able to go home. Minor side affects (less than 15% ) have been facial flushing and less frequently headaches over the initial 24-48 hours. Diabetic patients are warned that their serum glucose may rise but will revert to normal within 24-36 hours.

Although Buttermann did not report deep infection, the potential risk of sepsis would probably be less at caudal level. Patients telephone my office two days later to report back, are seen 1-2 weeks later and followed-up as necessary. The vast majority (in excess of 90%) report considerable symptomatic relief 1-2 days later. Looking ahead the pattern tends to follow “the rule of thirds” i.e. one third report short term relief lasting days some 1-2 weeks, one third have considerable relief (more than 75% subjective pain reduction) for a few months and the remainder have relief of up to one year or longer.

Based on my experience of patients who have had MR Scans prior to epidural, I found, unlike Dr Buttermann, the younger patient with a sequestrated disc has short term relief and would more likely fall into the group that opts for early surgery. The younger patient with a herniated disc has a better chance of avoiding surgery. When the far lateral disc is in the foramen or root canal I have found that the results are similar to when the impingement is more central. In the case of a recurrent disc herniation my experience has been that these cases have short term symptomatic respite i.e. relief which may last a couple of weeks. The older patient with multi level degenerative pathology namely central and/or root canal impingement has a relatively poor prognosis following epidural. However this is invariably the patient who would be best served with a non-operative approach and occasionally a gratifying response lasting months is achieved and the epidural may be repeated. Since the morbidity of caudal epidural steroid infiltration is so low, I encourage patients who have had relief of more than 3 months to have the procedure repeated before looking to a more active approach.

1. Scher MA. Caudal Epidural Analgesia for Neurogenic Leg Pain. S AFR MED J 1986:69:668

To the Editor:

In his recent letter, Dr. McLain posed a question about whether our results would have been different if there were there no crossover group. That is, once the patient was randomized to the epidural steroid injection group, he/she would have been prevented from crossing over to the discectomy group. The simple answer is that patients would have gone elsewhere for treatment had they had a failure of epidural steroid injection and had already previously failed trials of physical therapy, chiropractic, medications, etc.

One should note that enrolling patients into this type of study is very time consuming and I think that to try and enroll patients into a study where there would be no crossover group permitted, would be extremely difficult with so many patients opting not to participate that any results would be invalid as the few enrolled patients would not be representative of HNP patients as a whole.

But more to the point, I think that in the long-term (one year or more), there would have been improvement in the majority of patients regardless of treatment. I believe our treatments improve the quality of life in the relative short to moderate term follow-up period. This study did not specifically analyze the scenario that Dr. McLain questions and thus, my answers are speculative.

Dr. McLain also asked for clarification of the crossover group in the figures of the outcome scores. This is probably most easily seen in Figure #3 which demonstrates that as a group, the patients who considered themselves failures of epidural steroid injection still had some mild improvement in their outcome scores. For the hypothetical case that Dr. McLain refers to, I think that this group of patients, had they not have been allowed to cross over to discectomy, would have had higher (worse) scores over the first six to twelve months, but then at one to two years, would have probably had scores similar to the discectomy group. However, this was not addressed in the study and thus, my comments remain speculative.

Finally, my clinical impression is in agreement with the comments made by Dr. McLain -- surgical treatment provides rapid relief of symptoms but that in the long term, that is one to two years later, symptoms would probably be fairly similar in all groups. Thus, I feel discectomy or successful epidural steroid injections in the patients in our study who were treated after a minimum of six weeks of nonoperative treatment, provided significant improvement in their quality of life within the first year from symptom onset.

I think that the take home message of this study is that we can improve patients' symptoms substantially in the first few months and allow them to become functional again in a reasonable amount of time (weeks rather than years). The indications for treatment for many orthopaedic procedures is to get people functional in a timely fashion so they can become productive again and avoid the financial and emotional hardships of prolonged pain and disability.

Thank you.

Glenn R. Buttermann, M.D.

To the Editor:

I would like to compliment Dr. Buttermann on a well conceived and executed study, presented in "Treatment of Lumbar Disc Herniation: Epidural Steroid Injection Compared with Discectomy" (2004; 86:670-679). This study supports the commonly held notion that discectomy provides rapid pain relief and accelerates recovery, but does not promise a quantifiably better result in the long run.

However, the open crossover design muddies the results a bit. Would a design that prevented crossover, at least for a defined period of many months to a year (a common clinical scenario in managed care and worker's compensation systems) have provided the same results?

It is unclear from my reading whether the timetable for the crossover group was in step with the steroid group or the surgical group. If the values recorded for monthly intervals were measured from the time of the ESI, then these patients are included in some but not all of the data- points in Figures 1 and 2. These patients were at least somewhat improved when they opted to crossover, though to what degree is unknown. The "n" for the "Epidural" group would have also changed during early follow-up.

On the other hand, if the timetable for the crossover group was reset to the time of surgery, then post-injection follow-up data may not be included in these figures, where it would raise early ESI scores relative to other groups. Also, if those patients had been retained in the ESI group over the course of an entire year, their true response to ESI would have been seen. Either: 1) the failed ESI patients would have persisted as failures, elevating the subsequent pain and motor deficit scores throughout the remaining timepoints and amplifying the clinical efficacy of surgery, or; 2) these patients would have also experienced clinical improvement over the subsequent months, consistent with previous observations of ESI, (1).

Since the improvement seen with surgical treatment, relative to ESI, was only significant in the early follow-up period, and since the improvement seen with ESI, relative to placebo or untreated controls, is also only significant during the earliest post-treatment intervals,(2 - 5), it might be argued that the treatment of HNP with discectomy is effective only in providing more rapid recovery, with no expectation of incremental longterm benefit. It is difficult to argue, from the data available here, that the crossover group's good final outcome was the result of subsequent surgical treatment as opposed to the eventual arrival of healing promised by natural history. Perhaps the author's insight could clarify this important aspect of the study.

References: 1.Watts RW. Silagy CS: A meta-analysis on the efficacy of epidural corticosteroids in the treatment of sciatica. Anaesth Intens Care 1995; 23:564-9. 2.Abram SE. Treatment of Lumbosacral Radiculopathy with Epidural Steroids. Anesthesiology 1999; 91(6): 1937 - 1941. 3.Bush K, Hillier S: A controlled study of caudal epidural injections of triamcinolone plus procaine for the management of intractable sciatica. Spine 1991; 16:572-575. 4.Carette, S, Leclaire, R, Marcoux, S, Morin, F, Blaise, GA, St-Pierre, A, Truchon, R Parent, F, Levesque, J, Bergeron, V, Montminy, P, Blanchette, C: Epidural corticosteroid injections for sciatica due to herniated nucleus pulposus. N Engl J Med 1997; 336:1634 - 40. 5. Ridley MG, Kingsley GH, Gibson T, Grahame R: Outpatient lumbar epidural corticosteroid injection in the management of sciatica. Br J Rheumatol 1988; 27:295-299. Respectfully,

Robert F. McLain, M.D. Member, Surgical Staff Fellowship Director, Spine Fellowship Program Cleveland Clinic Spine Institute The Cleveland Clinic Foundation