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|Year : 2018 | Volume
| Issue : 6 | Page : 1711-1712
Selective dorsal root ganglion pulsed radiofrequency lesioning combined with gabapentin in the treatment of postherpetic neuralgia: The unanswered questions
Jason P Dauffenbach1, Manish Singh Sharma2
1 Department of Pain Management, Mayo Clinic Health System, Mankato, Minnesota 56001, USA
2 Department of Neurosurgery, Mayo Clinic Health System, Mankato, Minnesota 56001, USA
|Date of Web Publication||28-Nov-2018|
Dr. Manish Singh Sharma
Department of Neurosurgery, Mayo Clinic Health System, Mankato, Minnesota 56001
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Dauffenbach JP, Sharma MS. Selective dorsal root ganglion pulsed radiofrequency lesioning combined with gabapentin in the treatment of postherpetic neuralgia: The unanswered questions. Neurol India 2018;66:1711-2
|How to cite this URL:|
Dauffenbach JP, Sharma MS. Selective dorsal root ganglion pulsed radiofrequency lesioning combined with gabapentin in the treatment of postherpetic neuralgia: The unanswered questions. Neurol India [serial online] 2018 [cited 2019 Apr 23];66:1711-2. Available from: http://www.neurologyindia.com/text.asp?2018/66/6/1711/246228
Huang et al. in their article “Clinical observations on selective dorsal root ganglion pulsed radiofrequency lesioning combined with gabapentin in the treatment of postherpetic neuralgia” attempt to address the lacunae in the effective treatment of a very common yet painfully disabling condition that tends to affect an elderly subset of the population. They compare the use of gabapentin at doses of 2400 mg per day versus using this with selective dorsal root ganglion pulsed radiofrequency lesioning. As per their data, the rate of effective treatment as defined in their study, increased from 70.7% to 86.2%. This was statistically significant.
While the authors are to be congratulated for these results, there are a number of clinically relevant questions that are elucidated below.
The outcomes chosen for this observational study are not entirely well defined, aside from the ubiquitous visual analog score (VAS) and “no severe complications.” The total effective rate appears to be either a novel or a rarely used assessment of the objective response rate. It may be argued that this is a mere extrapolation of the VAS data as anything above a VAS change of 50% was classified as ‘effective’. Incorporating robustly validated and commonly reported pain indices such as the Brief Pain Inventory- Short Form, Neuropathic Pain Scale, and/or the McGill Pain Scale would have added greater clarity to the conclusions. On the contrary, the emphasis on immune and inflammatory indices shifts the focus away from reported clinical observations which the title of the article clearly highlights.
Additional data regarding the technique used for trigeminal nerve pulsed radiofrequency lesioning, which was carried out in 9 of 58 observational subjects, would have been useful. Although, the chosen parameters for pulsed radiofrequency fall within commonly reported and recommended ranges, the authors fail to clarify the rationale for repeating the 120 second therapy cycle and whether this could have impacted the clinical outcomes.
The rationale behind using a dosing regimen of gabapentin at 2400 mg, administered thrice daily, is also not explained. Common clinical practice for dosing of neuromodulating medications is to reach a maximal daily dose (3600 mg/day of gabapentin in this case) or a maximum tolerable dose, as limited by the side effects of the medication. Furthermore, the authors fail to report the presence or absence of adverse side effects in either the control or observational groups. Although, the inclusion criteria outline “good treatment compliance”, the article does not reveal medication tolerance or adherence.
As regards, dorsal root ganglion pulsed radiofrequency lesioning improving the immune functioning of these patients, we feel that this reasoning may be a trifle over- arching. It is possible that the difference in the reported immune and inflammatory indices between the control and observational groups may reflect a natural response to procedural stress. It is also interesting to note that, in this group of largely healthy individuals with severe post herpetic neuralgia, the mean age was essentially in the mid- 40s. This is far younger than that reported in world literature.
Finally, the reader is left without the ability to infer a dose dependent effect of gabapentin and the unanswered question about whether or not the observed results of the use of selective dorsal root ganglion pulsed radiofrequency lesioning would vary in patients taking lower or higher doses of this neuromodulating agent.
| » References|| |
Huang Y, Luo F, He X. Clinical observations on selective dorsal root ganglion pulsed radiofrequency lesioning combined with gabapentin in the treatment of postherpetic neuralgia. Neurol India 2018;66:1706-10. [Full text]