Keywords
occipital neuralgia - neurostimulation - spinal cord stimulation - case report
Palavras-Chave
neuralgia occipital - neuroestimulação - estimulação da medula espinhal - relato de
caso
Introduction
Refractory occipital neuralgia is a difficult medical condition, especially when the
patient has already been submitted to occipital nerve neurectomy and radiofrequency
rhizotomy. There is no case report of spinal cord stimulation in the C1-C4 cervical
segments for this condition.
Presentation
The patient (SCTA) was a 42-year-old female with a medical report of 2 years of refractory
pain in the occipital region. She was submitted to anesthetic and corticoid blocks,
and experienced partial resolution for months. The surgical approach for neurectomy
of the major and minor occipital nerves was performed, and the patient showed no improvement
after 3 months; instead, she experienced recurrence, worsening of the pain and refractoriness
of the drugs (pregabalin 600 mg/day plus duloxetine 60 mg/day plus methadone 20 mg/day).
During this period, she was referred to our service. The proposed initial treatment
was pulsed radiofrequency in the C2 ganglion and C3 root. We achieved a reduction
of 30% in the score of the visual analogue scale (VAS) after two attempts with no
medication withdrawn. As there was a large portion of scar tissue in the occipital
region, the introduction of a C1-C4 spinal cord neurostimulator by laminectomy was
proposed.
Technical Note
The patient was under general anesthesia, in the prone position, with the head on
a 3-pin holder. We performed unilateral exposure of the laminas of C1 until C4, and
a small C4 laminectomy for the placement of the neurostimulator lead under the laminas
of C2, C3 and C4 until the lateral portion of C1. We had to expose the C1 posterior
arc and epidural space in order to guide the lead, and we checked the radioscopy to
make sure the 16-electrode surgical lead (Medtronic, Inc. Minneapolis, MN, US) was
properly placed ([Fig. 1]). We turned the patient and performed an intraoperative awake test with an external
trialing neurostimulator (Medtronic, Inc. Minneapolis, USA) to evaluate the covering
pain area. Once we matched the area of pain with the neurostimulation, we connected
the system and placed the neurostimulator's battery into the abdominal wall.
Fig. 1 Dorsal cord stimulation for occipital neuralgia. (A) Preoperative photograph of the patient. Note the scar from the previous procedure
and the painful stitches drawn on the scalp. (B) Radioscopy in profile showing the position of the electrodes from C4 to C1. (C) Intraoperative radioscopy in anterior-posterior view showing the position of the
16- electrode surgical lead.
Results
There was an important improvement in pain with a significant reduction in the use
of pain medication progressively. After 12 months of implantation, the visual analogue
scale score was 2, and the patient successfully achieved methadone and pregabalin
withdrawal. The patient is currently using only duloxetine 60 mg/day ([Fig. 2]).
Fig. 2 Visual analogue scale follow-up after spinal cord stimulation. Visual analogue scale
versus medication 1, 3, 6 and 12 months after surgery. Abbreviations: DLX, duloxetine;
MTD, methadone; PGB, pregabalin; VAS, visual analogue scale.
Discussion
Occipital neuralgia is often controlled with muscle relaxants, physical therapy, and
anesthetic blocks with corticosteroids. In refractory cases, the intervention option
is necessary.[1] Currently, the most recommended interventions are performed with botulin toxin[2] or pulsed radiofrequency.[3] If refractoriness occurs, performing a neurectomy or a gangliectomy[4] are options with controversial results, because they can worsen the painful condition.[1] In this case, the patient had already taken anesthetic blocks with corticosteroids,
with improvement only while the effect of the anesthetic lasted. The patient underwent
an open surgery for neurectomy, but she showed no improvement after 3 months. Pulsed
radiofrequency was then attempted twice, with the condition showing little improvement.
The option for spinal cord stimulation instead of peripheral nerve stimulation[4]
[5] was made because of the large portion of scar tissue in the occipital region and
the medical report of neurectomy of the occipital nerves. In this case, we could not
introduce the lead under the C1 arc (perhaps because of the previous manipulation),
and we had to expose the C1 posterior arc and the epidural space to place the 16-electrode
surgical lead under C1.
As soon as there was correspondence between the area of pain and the stimulated area,
we decided to place the generator at the same surgical time. Good pain control was
achieved through a significant visual analogue scale reduction of 80% and withdrawal
from the medications. The VAS score of 2 in the affected area may be related to the
area stimulation itself.
The option for the dorsal cord stimulator between C1and C4 can allow adequate central
control in these cases of refractory occipital neuralgia. It allows greater covering
area by the stimulation and more programs possibilities in the follow-up control.
Another advantage of dorsal cord stimulation at this level is the anatomical characteristic
of the cervical plexus and the occipital nerves with numerous anastomoses as well
as the possibility of activation of adjacent cervical spinal areas and trigeminal
nuclei.[1]
[4] The greatest negative point of the technique presented is the port site of the surgery;
the procedure should be performed by a neurosurgeon with knowledge of the anatomy
of the occipital and cervical regions. The postoperative period was well-tolerated
by our patient, with a good pain control outcome.
Spinal cord stimulation between the C1 and C4 cervical segments can be an option for
selected cases of refractory occipital neuralgia, including those patients who have
already been submitted to neurectomy or rhizotomy.
