Motor Response after Dorsal Root Ganglion Stimulation: A pilot study of 10 patients with Motor Complete Paraplegia.

Spinal Cord Stimulation (SCS) en Dorsal Root Ganglion (DRG) stimulation are
considered to be accepted treatment modalities for the indication of pain. In
2014, the research group of Angeli et al. proved that spinal cord stimulation
can evoke motor response and even voluntary movements in patients with motor
complete paraplegia. However, spinal cord stimulation has many disadvantages,
which prevents a broad, clinical implementation of the DRG stimulator for motor
response in patients with paraplegia. We propose the more direct form of DRG
stimulation as a fruitful alternative.

In a previous, still-ongoing pilotstudy we have so far been able to evoke motor
response in 6 patients implanted with a DRG stimulator for the indication of
pain management. From this we have been able to conclude that DRG stimulation
indeed can lead to a motor response in these intact patients. The study is
still ongoing in order to reach the target of 10 included patients, before
finishing up the study and publishing the results.

As indicated in the protocol of the pilotstudy with these intact patients, we
would like to perform a follow-up study investigating the possibility to evoke
motor responses in patient with spinal cord injury, using DRG stimulation.

The aim of this case series is to investigate if DRG stimulation can evoke
motor responses in the lower extremities in patients with motor complete spinal
cord injury. This will be measured using EMG.

Prospective case series

All ten patients in this pilot study will receive a surgical placement of a DRG
stimulator. In addition, they will undergo EMG measurements and other tests
(see section on primary and secondary outcomes) to objectify the possible
effect of DRG stimulation on motor response. The controls consist of the intact
patients used in the previous pilot (MEC-2015-575).

The only risks the patient would be exposed to are the risks that come with the
temporary surgical placement of the DRG stimulation device. This treatment has
been performed many times in the Center for Pain Medicine of the Erasmus MC
with low complication rates. Although we will subject the patients to a
surgical placement of the DRG stimulator before EMG measurement, the treatment
itself will be performed under local anesthesia. In addition, risks such as
epidural hemorrhage, infection, spinal cord compression, cerebrospinal fluid
(CSF) leakage, paralysis, weakness, numbness, or pain below the level of the
implant, are considered to be very low when performing the procedure in
patients for the indication of pain. Especially given the fact that our
patients will have the stimulator in situ for only three days (instead of the
usual two week proof period of DRG stimulator placement), we expect the risks
to again be minimized.
We also consider the radiation exposure during the surgical placement of the
stimulator in the OR (1.6 mSv) to be acceptable, especially in comparison to
the background radiation found in the Netherlands (2.0-2.5 mSv).

We also conclude that the burden of EMG measurements and physical examination
can be considered to be minimal.