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Case Report Volume 18 Issue 3
Transforaminal periradicular administration of onabotulinumtoxinA targeting the dorsal root ganglion environment for the treatment of refractory postherpetic neuralgia: case report and technical note
Cristopher García-Quintero MD, Miriam Alejandra Ruelas-Vitela, Celina Castañeda de la Lanza, Gabriela Judith Castañeda Hernandez, Arechiga Ornelas Guillermo Eduardo, Bonilla Flores Jorge
Received: July 16, 2026 | Published: July 28, 2026
Citation: García-Quintero C, Ruelas-Vitela MA, Lanza CCL, et al. Transforaminal periradicular administration of onabotulinumtoxinA targeting the dorsal root ganglion environment for the treatment of refractory postherpetic neuralgia: case report and technical note. J Anesth Crit Care Open Acce. 2026;18(3):69-72. DOI: 10.15406/jaccoa.2026.18.00655
Abstract
Introduction: Postherpetic neuralgia is one of the most debilitating forms of chronic
neuropathic pain, and a significant percentage of patients experience persistent pain
despite multimodal pharmacological treatment and conventional analgesic interventions.
Although onabotulinumtoxinA has demonstrated efficacy via intradermal and subcutaneous
injections, evidence regarding its periradicular administration through a transforaminal
approach targeting the dorsal root ganglion is very limited.
Clinical case: We present the case of a 69-year-old woman with refractory postherpetic
neuralgia in the left T6 dermatome of two years’ duration, characterized by intense
neuropathic pain (END 9/10; DN4 10/10), mechanical allodynia, hyperesthesia, and
dysesthesia. The patient did not achieve a satisfactory clinical response after multiple
pharmacological and interventional treatments, including gabapentinoids, antidepressants,
opioids, intravenous analgesic infusions, an 8% capsaicin patch, subcutaneous infiltration
of onabotulinumtoxinA, erector spinae plane block, and transforaminal block with local
anesthetic.
Intervention: Fluoroguided periradicular administration was performed via a left thoracic
transforaminal approach at the T6 level, administering 60 IU of botulinum toxin type A
diluted in 0.2% ropivacaine, after confirming the periradicular distribution with contrast
medium and ruling out vascular uptake.
Results: At eight weeks, pain intensity decreased from END 9/10 to 2/10, and the DN4 score
decreased from 10 to 2. Near-complete resolution of allodynia, significant improvement
in hyperesthesia and dysesthesia, an approximate 70% reduction in the daily methadone
dose, and clinically relevant functional and sleep improvements were also observed. No
procedure-related complications were recorded during the follow-up period.
Conclusion: Transforaminal periradicular administration of onabotulinumtoxinA targeting
the dorsal root ganglion was technically feasible and was associated with clinically relevant
improvement in this patient with refractory postherpetic neuralgia. Although this case
does not allow us to establish causal relationships, this approach represents a potentially
promising interventional strategy that warrants evaluation in prospective studies with a
larger number of patients.
Keywords: Transforaminal periradicular
©2026 García-Quintero, et al. This is an open access article distributed under the terms of the, which permits unrestricted use, distribution, and build upon your work non-commercially.
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