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01-04-2017 | Author's reply
Reply to the Letter to the Editor of M. Avellanal concerning: “Cost-effectiveness of conservative versus surgical treatment strategies of lumbar spinal stenosis in the Swiss setting: analysis of the prospective multicenter Lumbar Stenosis Outcome Study (LSOS)” by A. Aichmair et al. (Eur Spine J; 2016. doi:10.1007/s00586-016-4937-y)
Published in: European Spine Journal | Issue 4/2017
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We agree that definitive recommendations regarding treatment strategies cannot be solely based on cost-effectiveness studies. Of course, the health-economic consideration is only one of many to be included in the decision-making process. We appreciate the constructive discussion of the limitations of the conducted cost-effectiveness study and would like to respond in a point-by-point manner:-
The a priori definition of inclusion criteria of the LSOS cohort included diagnosis of LSS, a minimum age of 50 years, neurogenic claudication, available magnetic resonance and/or computed tomography imaging studies, and an absence of vertebral fractures, spine infection, scoliosis, or clinically relevant peripheral artery occlusive disease.
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Certainly, further studies, with a longer follow-up and larger sample size, are necessary to separately analyze cost effectiveness of other kinds of treatment strategies, such as pulsed radiofrequency, transforaminal infiltration, among others.
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ASA status was not specifically compared between groups but other scores that might indirectly reflect the overall health status of the patient, such as HRQoL and SSM as well as demographical data. Since none of these variables showed a statistically significant difference between the two main study sub-groups, we believe that comparability can be assumed. To our experience, even relevant medical comorbidities rarely totally contraindicate a surgical procedure, depending on the indication. Moreover, Parkinson disease is not considered a contraindication for spine surgery per se, although it has previously been associated with a worse postoperative outcome [1].
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We believe that the indication for a surgical intervention should not only be based on the numeric pain score alone, but also characteristics of other symptoms than pain (neurological function, among others), health-related quality of life, and as you mentioned, absent response to conservative treatment measures. A score of >5–6 on the NRS scale might indicate a relevant degree of suffering for the patient, with inter-individual differences in the subjective experience of pain [2].
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CT-guided epidural infiltration is a well-established alternative to fluoroscopically controlled infiltration [3‐5]. Low-dose CT protocols allow an average dose reduction of more than 85% [6, 7], so that the radiation exposure difference to the fluoroscopically guided technique is reduced. Furthermore, in our hands, the CT-guided infiltration is safe, fast, and reliable. To the best of our knowledge, large-scale randomized studies comparing both imaging-guided techniques are not yet available; however, this research question is currently under investigation at the authors’ institution.
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The better outcome for single compared to multi-level surgery concurs with the results of another study of the LSOS Study Group: even in the setting of multi-level lumbar spinal stenosis, a single-level decompression may be associated with a significantly better outcome in terms of SSM symptoms and function score, as opposed to multi-level decompression [8].
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The conservative treatment was not limited to the use of NSAIDs but a multimodal analgesic treatment including opioids and/or other analgesics.
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Even if spinal cord stimulation might be considered in the setting of failed back surgery by some, it certainly is not an established procedure in the setting of standard lumbar spinal stenosis [9].
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Obviously, a large-scale randomized controlled trial would create a higher level of evidence.