To identify the mechanism(s) of pain in patients with chronic pain after inguinal hernia repair.
ID
Source
Brief title
Condition
- Skin and subcutaneous tissue therapeutic procedures
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
The difference between post minus pre HFS measures regarding the subjective
intensity (VAS) and the event-related potential amplitude compared between
patients with chronic pain and patients without pain. The nature of pain will
be classified using the DN4 (Douleur Neuropathique en 4 Questions).
Secondary outcome
To investigate the nature of the pain, i.e. whether it is of neuropathic origin
or not. To document the presence of depressive symptoms. To document the amount
of catastrophising. To document the quality of life .
Background summary
Persistent postoperative pain (pain that persist long after the initially
surgical injury has healed) is a major social and medical problem because it
significantly affects quality of life and is difficult to treat. The
understanding of the underlying neurobiology is limited, but a fundamental
underlying mechanism appears to be abnormal persistence and spread of central
sensitisation, expressed as persistent and spreading hyperalgesia (i.e.
increased pain sensitivity) in non-damaged tissues. Nerve damage due to the
surgery seems to play a key role in this context. This is because nerve injury,
apart from itself directly producing marked central sensitization, is
particularly efficient at producing a pro-nociceptive state by depressing
inhibitory descending modulation (disinhibition) and favouring the process of
descending facilitation. Both processes will result in more hyperalgesia in
skin areas surrounding or remote from the surgical area. This study proposes to
investigate the facilitating state accompanying chronic pain associated with
nerve damage by using an experimental pain model (high frequency electric skin
stimulation = HFS) to study the ease of inducing secondary hyperalgesia in
patients with or without chronic pain after nerve-damaging inguinal surgery.
Study objective
To identify the mechanism(s) of pain in patients with chronic pain after
inguinal hernia repair.
Study design
Observational study, mixed design (pre vs. post HFS, comparison between
patients with and without chronic pain). All subjects will receive four trains
of 20 nociceptive test stimuli quantified by simultaneous determination of ERPs
and Visual Analogue Scale (VAS), with the conditioning stimulation (HFS) in
between
Study burden and risks
The burden is small and consists of a visit to the UMC, having a paintest and
filling in a few questionnaires. The total time occupied with the study per
patient is maximal 3.5 hours.!
postbus 9101
6500 HB Nijmegen
NL
postbus 9101
6500 HB Nijmegen
NL
Listed location countries
Age
Inclusion criteria
Presence of chronic pain as a result of inguinal hernia repair (local pain) for the experimental group
No pain aftere inguinal hernia repair for the control group
6 to 7 years after surgery (operated between April 2001 and March 2003)
Aged 18 - 65 year
Men
Ability to give informed consent
Ability to understand the research and follow the instructions during the experiment
Exclusion criteria
Presence or history of other neurological or major psychiatric diseases
Regular intake of medication affecting potentially brain function or EEG signal (e.g., psychopharmacological drugs; morphine, anti-psychotics, anti-depressives, anti-epileptica, benzodiazepines)
Regular legal or illegal drug intake
Any pre-existing type of chronic pain syndrome
No participation in other research
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 | NL32573.091.10 |