This mapping study will contribute to our understanding of the pathogenesis of ACNES and the complex anatomical distribution of sensory input of the trunk. It will also pave the way for a better diagnostic work-up, allowing for better surgical…
ID
Source
Brief title
Condition
- Peripheral neuropathies
- Nervous system, skull and spine therapeutic procedures
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
The number of patients who confirm a one to one correlation between the
clinical suspected anatomical dermatome in which their ACNES pain point is
located and the corresponding dorsal root ganglion with RTPM
Secondary outcome
Electrophysiological aspects:
- If no one to one correlation is present, what is the mean number of DRG*s
involved.
- The relative contribution per DRG of elicited pain in the pain point in
percentages.
- Anatomical distribution of the elicited paresthesia using a drawing map
- The mean mV to illicit a pain response.
Differentiation between peripheral and central sensitized pain:
- The number of patients who report instantaneous complete remission of pain
caused by a procedure after local anaesthesia in the targeted DRG*s.
Pain reduction:
- Mean pain reduction on a Numeric Pain Rating Scale after PRF treatment
compared to baseline directly after treatment and 2 weeks and 6 weeks after
treatment.
- The percentage of patients with a >30% and >50% pain reduction on a NPRS.
Background summary
Anterior Cutaneous Nerve Entrapment Syndrome (ACNES) is a condition in which
patients develop chronic neuropathic pain in the abdominal wall due to
entrapped intercostal nerve terminals. The diagnosis is an old fashioned
clinical one that is based upon the patient*s history and physical examination.
It is usually confirmed by an injection with a local anesthetic agent into the
so-called *pain point*: a point of maximal pain that is residing within the
lateral edges of the rectus abdominis muscle. Such an abdominal wall injection
is supposed to give a quick but often transient pain reduction if the diagnosis
is valid.
However, sometimes this diagnostic injection gives inconclusive results (e.g.
the pain is not responding although the diagnosis of ACNES is highly likely) .
If so, a pain specialist performs an ultrasound or X-ray guided injection at
multiple levels of the neural pathway of the intercostal nerve to assess at
what level the pain arises, sometimes eventually blocking the nerve and
establishing pain reduction at another level than the m. abdominis. The
findings of this practice, combined with recent literature about the complex
network of sensory innervation of the trunk and abdominal wall, confirmed the
need for more extensive *pain mapping* of ACNES patients.
A promising technique possible allowing for a more focused approach is
retrograde transforaminal paresthesia mapping (RTPM). This specific procedure
is commonly performed as a precursor to (pulsed) Radio Frequency (pRF) ablation
of the dorsal root ganglion (DRG) and as a predictor for the success of
implantation of a spinal cord stimulation device.
Study objective
This mapping study will contribute to our understanding of the pathogenesis of
ACNES and the complex anatomical distribution of sensory input of the trunk. It
will also pave the way for a better diagnostic work-up, allowing for better
surgical therapy results. Moreover, it could predict whether ACNES is a
condition which can be treated with spinal cord stimulation techniques that are
currently under trial in our center for patients with chronic neuropathic groin
pain. Finally, it may be an alternative treatment option, since blocking or
interference with the DRG using pRF may lead to pain relief.
Study design
Interventional pilot study.
Intervention
Retrograde transforaminal paresthesia mapping (RTPM) followed by pulsed radio
frequency (pRF) treatment.
Study burden and risks
Possible: pain during the procedure (RTPM as well as pRF), pain in the back
after the procedure, increase in pain intensity of the ACNES pain, transient
loss of motor control in the legs and pneumothorax.
Description RTPM: The patient is positioned on his abdomen on the OR table. The
back is sterilized. Three hollow needles are placed in the targeted dorsal root
ganglia by the pain specialist using fluoroscopy. Then using short electrical
stimulation the patient is asked to score the way in which each ganglion
contributes to his painful spot on the abdominal wall. This is done for each
DRG separately: in between stimulations there will be a pause of 3 minutes.
Then the PRF procedure is started. The DRG's which contributed >10% to the
painful spot are stimulated with an electrical current during 6 minutes, thus
warming them to 42 degreees, what will positively influence the neural
activity.
Ds. Th. Fliednerstraat 1
Eindhoven 5631 BM
NL
Ds. Th. Fliednerstraat 1
Eindhoven 5631 BM
NL
Listed location countries
Age
Inclusion criteria
•Clinical diagnosis of ACNES:
•Localisation ACNES unilateral
•Clear, discrete pain point over the m. rectus abdominis
•Symptoms get worse upon flexing the abdominal muscles (Carnett*s sign positive)
•Good temporary effect of one local injection at the ACNES pain point with a local anesthetic. ;•Informed consent obtained and good apprehension of the procedure warranted
•Minimum age 18 years
Exclusion criteria
•Pregnancy
•Allergy or hypersensitivity to lidocaine
•Prior treatment for ACNES, such as peripheral nerve blocks, Pulsed-Radio-Frequency, epidural injections, etc.
•Adequate follow-up not warranted, for example because of mental retardation, dementia or a language barrier
•Spinal surgical procedures at or between vertebral levels Th8-L2 in medical history
•Known coagulation disorders or use of anticoagulants
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL52578.015.15 |