Dorsal root ganglion (DRG) stimulation is an effective
treatment for chronic, refractory complex
regional pain syndrome (CRPS). Routinely, the
placement of a DRG stimulator lead is based
on established anatomical knowledge of dermatomes.
In patients with lumbosacral transitional
vertebral anatomy, dermatome maps are not
dependable due to dermatomal variance. This
can make correct placement of stimulator leads
challenging as the supposed target may not actually
be responsible for sensing the painful area.
We present a case of a 60-year-old woman with
CRPS and lumbarization of the S1 vertebral body
(presence of 6 lumbar vertebrae and 4 sacral
vertebrae) who failed a DRG stimulator trial after
using conventional dermatome maps to identify
target DRGs assuming that the nerve exiting below
L6 corresponded to the S1 dermatome. Following
the failed trial, sensory stimulation of the DRG via
radiofrequency stimulation was used to accurately
map dermatomes leading to a successful DRG
stimulation implant at a DRG level that differed
from expected based on traditional dermatome
maps. Thus, DRG stimulation may guide decisionmaking
in regard to target stimulation in patients
with abnormal vertebral anatomy.
Key words: Dorsal root ganglion stimulation,
dermatome mapping, radiofrequency stimulation,
spinal anomaly, lumbosacral transitional vertebrae,
complex regional pain syndrome, neuromodulation,
dermatomal variance
Dorsal root ganglion stimulation yielded higher treatment success rate for complex regional pain syndrome and causalgia at 3 and 12 months