Healthy SubjectsBI-LaserNCT02442726
Activation of A-delta-fibres and C-fibres in a First Degree Thermal Injury in Volunteers
A study testing CO2-Laser stimulation (Laser Stimulation Device, SIFEC) in people with Healthy Subjects, run by University of Copenhagen at 1 site in Denmark.
Trial summary
The aim of this study is to measure reaction times and thermal detection thresholds to CO2 laser stimulation of the skin, before and after a first degree thermal injury, in the primary and secondary hyperalgesia area, in order to investigate whether different nerve-fiber classes are activated in the post-injury phase. Read more about this study
- Who is it for?
- Ages 18 to 30 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Healthy Subjects
- What is being tested?
- CO2-Laser stimulation (Laser Stimulation Device, SIFEC)
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 18 participants
- Where
- 1 siteDenmark
- Study dates
- May 2015to Nov 2015
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 30 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- healthy right-handed males
- non-smokers (due to fluctuating skin temperatures in smokers)
- normal thermal perception (warmth detection threshold [WDT], cool detection threshold [CDT] and heat pain threshold [HPT])
- familiarized with the thermal injury and quantitative sensory testing
- understands written and verbal study information in Danish
- understands written and verbal study information in English
Who cannot join
- lesions on the lower leg
- unable to cooperate with the sensory testing
- suspected neurological disease
- hereditary predisposition to peripheral neurological disease
- inability to develop secondary hyperalgesia area (non-responder)14
- "small-area" responder (secondary hyperalgesia area < 36 cm2)
Show all 10Show fewer
- participated in pharmacological trials during the preceding 4 weeks
- participated in a thermal-injury trial during the preceding 8 weeks
- intake of any medication during the preceding 48 hours
- intake of prescription drugs during the preceding 7 days
Trial locations and contacts
1 site in 1 country.
Denmark1 site
BRAINLab, Department of Neuroscience and Pharmacology, Panum Institute
Copenhagen, 2200
About this study
The aim of this study is to measure reaction times and thermal detection thresholds to CO2 laser stimulation of the skin, before and after a first degree thermal injury, in the primary and secondary hyperalgesia area, in order to investigate whether different nerve-fiber classes are activated in the post-injury phase. The study results are expected to uncover existence of a peripheral inflammatory input contributing to secondary hyperalgesia.
Read the detailed description
BACKGROUND The conduction speed of peripheral nerve fibers depends on the nerve diameter. The conduction velocity of large myelinated fibers are 50 - 120 m/s, while for the smaller myelinated A-delta- and unmyelinated C-fibers, they are in the range of 5-10 m/s, and 0.5-1 m/s, respectively. Applying short laser pulses with a high energy density and synchronization, simple reaction times can be used to determine the type of fiber class that has been activated. Research from the group of Plaghki and colleagues has shown that when stimulating surface areas are between 15 and 50 sq.mm at a supra-threshold intensity for activating A-delta-fibers, a typical bimodal response pattern is observed with a first peak centered around 400 ms and a second around 850 ms. Whereas the early peak is due to activation of A-delta-fibers, the second peak is caused by C-fiber activation.
HYPOTHESIS Following a mild thermal skin injury (47ºC, 420 s, 9.0 or 12.5 sq.cm area) the injured area is associated with erythema and an increased sensitivity, i.e. pain is easily evoked by mechanical and thermal stimuli in the primary hyperalgesia area. In normal skin surrounding the injury mechanical and thermal allodynia and hyperalgesia, are present. Innocuous stimuli in this secondary hyperalgesia area may elicit pain. This is believed to be a central process suggested by pioneering research in the 1980s and 1990s. The term for this phenomenon is heterosynaptic central facilitation meaning that innocuous stimuli may activate normally high-threshold nociceptive dorsal horn neurons leading to allodynia. This conversion of an innocuous stimulus in normal skin just outside of the injury, to a pain generating stimulus, is the result of a change in the sensory processing within the CNS. This processing is probably regulated by spino-bulbo-spinal loops including the rostral ventro-medial medulla (RVM) and locus coeruleus (LC).
The study hypotheses are, first, that the reaction times at the thermal injury site (i.e. primary hyperalgesia area) are changed compared to the pre-injury level. Second, that the sensory changes in the secondary hyperalgesia area, following a thermal injury, are not exclusively centrally mediated, but that also changes in peripheral afferents, e.g. A-delta-fibers (AMH type I) are demonstrable by assessments of reaction times to CO2 laser pulses.
A well-known alternative to laser stimulation is the use of a contact thermode with a much larger stimulation area, i.e. 2.5 to 16 sq.cm. The substantially larger area of the contact thermode, combined with a slower heating rate, compared to the laser stimulus (< 0.5 sq.cm, 10 ms), may induce pronounced spatial and temporal summation, interfering with accurate interpretation of sensory data. A recent method-comparison study in patients with postherpetic neuralgia, comparing assessments obtained by a contact thermode (9 sq.cm) and by laser stimuli (< 0.25 sq.mm), indicates that the laser method is more sensitive and specific in detecting thermal sensory abnormalities. Since the laser stimulus gives a steeper slope of heating profile and a more synchronized activation of warmth- and heat-sensitive small fibers, i.e. C- and A-delta-fibers, in the skin laser stimulation is the preferred method in the present study.
CLINICAL IMPLICATIONS The propensity for developing secondary hyperalgesia may reflect a predisposition for developing persistent postsurgical pain. It has been estimated that 2-10% of patients undergoing otherwise uncomplicated surgical procedures will suffer from persistent postsurgical pain. Investigating the pathophysiological mechanisms behind secondary hyperalgesia may therefore increase our understanding of the transition to chronic pain and thereby improve our management strategies for this large patient group.
- Conditions
- Healthy Subjects
- Being tested
- CO2-Laser stimulation (Laser Stimulation Device, SIFEC)
- Keywords
- Heat Injury, Humans, Laser Stimulation, Quantitative Sensory Testing, Reaction Time, Secondary Hyperalgesia, Thermal Thresholds
- Medical subject headings
- Hyperalgesia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CO2-Laser stimulation (Laser Stimulation Device, SIFEC)Device
Laser stimuli are evenly applied in 15 spots (each 6 mm in diameter) in the primary hyperalgesic zone (application zone of the contact thermode) and in the secondary hyperalgesic zone (1 cm outside the application zone of the contact thermode).
| Study group | Role | What they receive |
|---|---|---|
| Thermal Injury | Active comparator | A first degree heat injury is induced by a contact thermode (12.5 cm2; 47C; 420 s) applied at the skin at the lower leg. CO2-Laser stimulation (Laser Stimulation Device, SIFEC) Receives: Device: CO2-Laser stimulation (Laser Stimulation Device, SIFEC) |
| Sham Injury | Sham comparator | A sham "injury" is induced by a contact thermode (12.5 cm2; 38C; 420 s) applied at the skin at the lower leg. CO2-Laser stimulation (Laser Stimulation Device, SIFEC) is used to assess Receives: Device: CO2-Laser stimulation (Laser Stimulation Device, SIFEC) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Changes in distribution of reaction times assessed by laser stimuli in the thermal injury area (the primary hyperalgesia area) comparing post-injury values with pre-injury, baseline values.
Assessments are performed at Baseline, 1 h post-thermal injury and 24 h post-thermal injury. Changes compared to Baseline are analyzed.
Measured: 24 hours
Changes in distribution of reaction times assessed by laser stimuli in the secondary hyperalgesia area comparing post-injury values with pre-injury, baseline values.
Assessments are performed at Baseline, 1 h post-thermal injury and 24 h post-thermal injury. Changes compared to Baseline are analyzed.
Measured: 24 hours
Secondary outcomes (4)
Changes in thermal pain thresholds assessed by laser stimuli in the thermal injury area (the primary hyperalgesia area) comparing post-injury values with pre-injury, baseline values.
Assessments are performed at Baseline, 1 h post-thermal injury and 24 h post-thermal injury. Changes compared to Baseline are analyzed.
Measured: 24 hours
Changes in thermal pain thresholds assessed by laser stimuli in the secondary hyperalgesia area comparing post-injury values with pre-injury, baseline values.
Assessments are performed at Baseline, 1 h post-thermal injury and 24 h post-thermal injury. Changes compared to Baseline are analyzed.
Measured: 24 hours
Thermal detection thresholds assessed by laser stimuli in the thermal injury area (the primary hyperalgesia area) comparing post-injury values with pre-injury, baseline values.
Measured: Baseline, 1 h post-thermal injury; 24 h post-thermal injury
Changes in thermal detection thresholds assessed by laser stimuli in the secondary hyperalgesia area comparing post-injury values with pre-injury, baseline values.
Assessments are performed at Baseline, 1 h post-thermal injury and 24 h post-thermal injury. Changes compared to Baseline are analyzed.
Measured: 24 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 May 2015 (estimated)
- Study startMay 2015
- Primary completionSep 2015
- Study completionNov 2015
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (16)Papers the sponsor has linked to this study.
- Other trials for Healthy SubjectsStudies of the same condition, open and under way.
- More trials run by University of CopenhagenThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 18 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Copenhagen
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, mads u werner, University of Copenhagen
- Investigators
- Mads U Werner, MD, DMSc, Principal investigator, Neuroscience Center, Copenhagen University Hospital, DenmarkRon Kupers, MSc, Study chair, Panum Institute, Copenhagen University, DenmarkHenrik Kehlet, MD, DMSc, Study chair, JMC, Copenhagen University Hospital, Denmark
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02442726
- Sponsor's protocol ID
- H-2-2014-002
- Acronym
- BI-Laser
- Status last verified
- Dec 2015
- First submitted
- 3 May 2015
- Last updated
- 3 Dec 2015
- Results posted
- No
- Data monitoring committee
- No
Publications
Pedersen JL, Kehlet H. Hyperalgesia in a human model of acute inflammatory pain: a methodological study. Pain. 1998 Feb;74(2-3):139-51. doi: 10.1016/s0304-3959(97)00160-7.
PubMed 9520228Naert ALG, Kehlet H, Kupers R. Characterization of a novel model of tonic heat pain stimulation in healthy volunteers. Pain. 2008 Aug 15;138(1):163-171. doi: 10.1016/j.pain.2007.11.018. Epub 2008 Jan 22.
PubMed 18207325Pedersen JL, Kehlet H. Secondary hyperalgesia to heat stimuli after burn injury in man. Pain. 1998 Jun;76(3):377-384. doi: 10.1016/S0304-3959(98)00070-0.
PubMed 9718256Torebjork HE, LaMotte RH, Robinson CJ. Peripheral neural correlates of magnitude of cutaneous pain and hyperalgesia: simultaneous recordings in humans of sensory judgments of pain and evoked responses in nociceptors with C-fibers. J Neurophysiol. 1984 Feb;51(2):325-39. doi: 10.1152/jn.1984.51.2.325.
PubMed 6707724Cook AJ, Woolf CJ, Wall PD. Prolonged C-fibre mediated facilitation of the flexion reflex in the rat is not due to changes in afferent terminal or motoneurone excitability. Neurosci Lett. 1986 Sep 25;70(1):91-6. doi: 10.1016/0304-3940(86)90443-x.
PubMed 3774223Woolf CJ, Wall PD. Relative effectiveness of C primary afferent fibers of different origins in evoking a prolonged facilitation of the flexor reflex in the rat. J Neurosci. 1986 May;6(5):1433-42. doi: 10.1523/JNEUROSCI.06-05-01433.1986.
PubMed 3711988Torebjork HE, Lundberg LE, LaMotte RH. Central changes in processing of mechanoreceptive input in capsaicin-induced secondary hyperalgesia in humans. J Physiol. 1992 Mar;448:765-80. doi: 10.1113/jphysiol.1992.sp019069.
PubMed 1593489LaMotte RH, Lundberg LE, Torebjork HE. Pain, hyperalgesia and activity in nociceptive C units in humans after intradermal injection of capsaicin. J Physiol. 1992 Mar;448:749-64. doi: 10.1113/jphysiol.1992.sp019068.
PubMed 1593488Werner MU, Petersen KL, Rowbotham MC, Dahl JB. Healthy volunteers can be phenotyped using cutaneous sensitization pain models. PLoS One. 2013 May 9;8(5):e62733. doi: 10.1371/journal.pone.0062733. Print 2013.
PubMed 23671631Franz M, Spohn D, Ritter A, Rolke R, Miltner WHR, Weiss T. Laser heat stimulation of tiny skin areas adds valuable information to quantitative sensory testing in postherpetic neuralgia. Pain. 2012 Aug;153(8):1687-1694. doi: 10.1016/j.pain.2012.04.029. Epub 2012 May 31.
PubMed 22657400Arendt-Nielsen L, Chen AC. Lasers and other thermal stimulators for activation of skin nociceptors in humans. Neurophysiol Clin. 2003 Dec;33(6):259-68. doi: 10.1016/j.neucli.2003.10.005.
PubMed 14678840Martinez V, Ammar SB, Judet T, Bouhassira D, Chauvin M, Fletcher D. Risk factors predictive of chronic postsurgical neuropathic pain: the value of the iliac crest bone harvest model. Pain. 2012 Jul;153(7):1478-1483. doi: 10.1016/j.pain.2012.04.004. Epub 2012 May 2.
PubMed 22560289Kehlet H, Jensen TS, Woolf CJ. Persistent postsurgical pain: risk factors and prevention. Lancet. 2006 May 13;367(9522):1618-25. doi: 10.1016/S0140-6736(06)68700-X.
PubMed 16698416Johansen A, Schirmer H, Stubhaug A, Nielsen CS. Persistent post-surgical pain and experimental pain sensitivity in the Tromso study: comorbid pain matters. Pain. 2014 Feb;155(2):341-348. doi: 10.1016/j.pain.2013.10.013. Epub 2013 Oct 18.
PubMed 24145207Plaghki L, Mouraux A. How do we selectively activate skin nociceptors with a high power infrared laser? Physiology and biophysics of laser stimulation. Neurophysiol Clin. 2003 Dec;33(6):269-77. doi: 10.1016/j.neucli.2003.10.003.
PubMed 14678841
Study at a glance
From the registry record, last updated by the sponsor on 3 Dec 2015. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Activation of A-delta-fibres and C-fibres in a First Degree Thermal Injury in Volunteers
- ClinicalTrials.gov ID
- NCT02442726
- Acronym / sponsor ID
- BI-Laser / H-2-2014-002
- Conditions
- Healthy Subjects
- Keywords
- Heat Injury, Humans, Laser Stimulation, Quantitative Sensory Testing, Reaction Time, Secondary Hyperalgesia, Thermal Thresholds
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 18 participants (actual)
- Lead sponsor
- University of CopenhagenUniversity, hospital or other
- Study start
- May 2015
- Primary completion
- Sep 2015 (actual)
- Study completion
- Nov 2015 (actual)
- First posted
- 13 May 2015 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of this study is to measure reaction times and thermal detection thresholds to CO2 laser stimulation of the skin, before and after a first degree thermal injury, in the primary and secondary hyperalgesia area, in order to investigate whether different nerve-fiber classes are activated in the post-injury phase. The study results are expected to uncover existence of a peripheral inflammatory input contributing to secondary hyperalgesia.
Detailed description
BACKGROUND The conduction speed of peripheral nerve fibers depends on the nerve diameter. The conduction velocity of large myelinated fibers are 50 - 120 m/s, while for the smaller myelinated A-delta- and unmyelinated C-fibers, they are in the range of 5-10 m/s, and 0.5-1 m/s, respectively. Applying short laser pulses with a high energy density and synchronization, simple reaction times can be used to determine the type of fiber class that has been activated. Research from the group of Plaghki and colleagues has shown that when stimulating surface areas are between 15 and 50 sq.mm at a supra-threshold intensity for activating A-delta-fibers, a typical bimodal response pattern is observed with a first peak centered around 400 ms and a second around 850 ms. Whereas the early peak is due to activation of A-delta-fibers, the second peak is caused by C-fiber activation.
HYPOTHESIS Following a mild thermal skin injury (47ºC, 420 s, 9.0 or 12.5 sq.cm area) the injured area is associated with erythema and an increased sensitivity, i.e. pain is easily evoked by mechanical and thermal stimuli in the primary hyperalgesia area. In normal skin surrounding the injury mechanical and thermal allodynia and hyperalgesia, are present. Innocuous stimuli in this secondary hyperalgesia area may elicit pain. This is believed to be a central process suggested by pioneering research in the 1980s and 1990s. The term for this phenomenon is heterosynaptic central facilitation meaning that innocuous stimuli may activate normally high-threshold nociceptive dorsal horn neurons leading to allodynia. This conversion of an innocuous stimulus in normal skin just outside of the injury, to a pain generating stimulus, is the result of a change in the sensory processing within the CNS. This processing is probably regulated by spino-bulbo-spinal loops including the rostral ventro-medial medulla (RVM) and locus coeruleus (LC).
The study hypotheses are, first, that the reaction times at the thermal injury site (i.e. primary hyperalgesia area) are changed compared to the pre-injury level. Second, that the sensory changes in the secondary hyperalgesia area, following a thermal injury, are not exclusively centrally mediated, but that also changes in peripheral afferents, e.g. A-delta-fibers (AMH type I) are demonstrable by assessments of reaction times to CO2 laser pulses.
A well-known alternative to laser stimulation is the use of a contact thermode with a much larger stimulation area, i.e. 2.5 to 16 sq.cm. The substantially larger area of the contact thermode, combined with a slower heating rate, compared to the laser stimulus (< 0.5 sq.cm, 10 ms), may induce pronounced spatial and temporal summation, interfering with accurate interpretation of sensory data. A recent method-comparison study in patients with postherpetic neuralgia, comparing assessments obtained by a contact thermode (9 sq.cm) and by laser stimuli (< 0.25 sq.mm), indicates that the laser method is more sensitive and specific in detecting thermal sensory abnormalities. Since the laser stimulus gives a steeper slope of heating profile and a more synchronized activation of warmth- and heat-sensitive small fibers, i.e. C- and A-delta-fibers, in the skin laser stimulation is the preferred method in the present study.
CLINICAL IMPLICATIONS The propensity for developing secondary hyperalgesia may reflect a predisposition for developing persistent postsurgical pain. It has been estimated that 2-10% of patients undergoing otherwise uncomplicated surgical procedures will suffer from persistent postsurgical pain. Investigating the pathophysiological mechanisms behind secondary hyperalgesia may therefore increase our understanding of the transition to chronic pain and thereby improve our management strategies for this large patient group.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Thermal Injury | Active comparator | Device: CO2-Laser stimulation (Laser Stimulation Device, SIFEC)A first degree heat injury is induced by a contact thermode (12.5 cm2; 47C; 420 s) applied at the skin at the lower leg. CO2-Laser stimulation (Laser Stimulation Device, SIFEC) |
| Sham Injury | Sham comparator | Device: CO2-Laser stimulation (Laser Stimulation Device, SIFEC)A sham "injury" is induced by a contact thermode (12.5 cm2; 38C; 420 s) applied at the skin at the lower leg. CO2-Laser stimulation (Laser Stimulation Device, SIFEC) is used to assess |
Who may qualify
- Ages
- 18 to 30 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- healthy right-handed males
- non-smokers (due to fluctuating skin temperatures in smokers)
- normal thermal perception (warmth detection threshold [WDT], cool detection threshold [CDT] and heat pain threshold [HPT])
- familiarized with the thermal injury and quantitative sensory testing
- understands written and verbal study information in Danish
Key exclusion criteria (10 listed)
- lesions on the lower leg
- unable to cooperate with the sensory testing
- suspected neurological disease
- hereditary predisposition to peripheral neurological disease
- inability to develop secondary hyperalgesia area (non-responder)14
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| CO2-Laser stimulation (Laser Stimulation Device, SIFEC)Laser stimuli are evenly applied in 15 spots (each 6 mm in diameter) in the primary hyperalgesic zone (application zone of the contact thermode) and in the secondary hyperalgesic zone (1 cm outside the application zone of the contact thermode). | Device | Sham Injury, Thermal Injury |
Primary outcome
Changes in distribution of reaction times assessed by laser stimuli in the thermal injury area (the primary hyperalgesia area) comparing post-injury values with pre-injury, baseline values.
Time frame: 24 hours
Assessments are performed at Baseline, 1 h post-thermal injury and 24 h post-thermal injury. Changes compared to Baseline are analyzed.
Changes in distribution of reaction times assessed by laser stimuli in the secondary hyperalgesia area comparing post-injury values with pre-injury, baseline values.
Time frame: 24 hours
Assessments are performed at Baseline, 1 h post-thermal injury and 24 h post-thermal injury. Changes compared to Baseline are analyzed.
4 secondary outcomes
Changes in thermal pain thresholds assessed by laser stimuli in the thermal injury area (the primary hyperalgesia area) comparing post-injury values with pre-injury, baseline values.
Time frame: 24 hours
Changes in thermal pain thresholds assessed by laser stimuli in the secondary hyperalgesia area comparing post-injury values with pre-injury, baseline values.
Time frame: 24 hours
Thermal detection thresholds assessed by laser stimuli in the thermal injury area (the primary hyperalgesia area) comparing post-injury values with pre-injury, baseline values.
Time frame: Baseline, 1 h post-thermal injury; 24 h post-thermal injury
Changes in thermal detection thresholds assessed by laser stimuli in the secondary hyperalgesia area comparing post-injury values with pre-injury, baseline values.
Time frame: 24 hours
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Dec 2015.
- Background: PubMed 9520228Pedersen JL, Kehlet H. Hyperalgesia in a human model of acute inflammatory pain: a methodological study. Pain. 1998 Feb;74(2-3):139-51. doi: 10.1016/s0304-3959(97)00160-7.
- Background: PubMed 18207325Naert ALG, Kehlet H, Kupers R. Characterization of a novel model of tonic heat pain stimulation in healthy volunteers. Pain. 2008 Aug 15;138(1):163-171. doi: 10.1016/j.pain.2007.11.018. Epub 2008 Jan 22.
- Background: PubMed 9718256Pedersen JL, Kehlet H. Secondary hyperalgesia to heat stimuli after burn injury in man. Pain. 1998 Jun;76(3):377-384. doi: 10.1016/S0304-3959(98)00070-0.
- Background: PubMed 6707724Torebjork HE, LaMotte RH, Robinson CJ. Peripheral neural correlates of magnitude of cutaneous pain and hyperalgesia: simultaneous recordings in humans of sensory judgments of pain and evoked responses in nociceptors with C-fibers. J Neurophysiol. 1984 Feb;51(2):325-39. doi: 10.1152/jn.1984.51.2.325.
- Background: PubMed 3774223Cook AJ, Woolf CJ, Wall PD. Prolonged C-fibre mediated facilitation of the flexion reflex in the rat is not due to changes in afferent terminal or motoneurone excitability. Neurosci Lett. 1986 Sep 25;70(1):91-6. doi: 10.1016/0304-3940(86)90443-x.
- Background: PubMed 3711988Woolf CJ, Wall PD. Relative effectiveness of C primary afferent fibers of different origins in evoking a prolonged facilitation of the flexor reflex in the rat. J Neurosci. 1986 May;6(5):1433-42. doi: 10.1523/JNEUROSCI.06-05-01433.1986.
- Background: PubMed 1593489Torebjork HE, Lundberg LE, LaMotte RH. Central changes in processing of mechanoreceptive input in capsaicin-induced secondary hyperalgesia in humans. J Physiol. 1992 Mar;448:765-80. doi: 10.1113/jphysiol.1992.sp019069.
- Background: PubMed 1593488LaMotte RH, Lundberg LE, Torebjork HE. Pain, hyperalgesia and activity in nociceptive C units in humans after intradermal injection of capsaicin. J Physiol. 1992 Mar;448:749-64. doi: 10.1113/jphysiol.1992.sp019068.
- Background: PubMed 23671631Werner MU, Petersen KL, Rowbotham MC, Dahl JB. Healthy volunteers can be phenotyped using cutaneous sensitization pain models. PLoS One. 2013 May 9;8(5):e62733. doi: 10.1371/journal.pone.0062733. Print 2013.
- Background: PubMed 22657400Franz M, Spohn D, Ritter A, Rolke R, Miltner WHR, Weiss T. Laser heat stimulation of tiny skin areas adds valuable information to quantitative sensory testing in postherpetic neuralgia. Pain. 2012 Aug;153(8):1687-1694. doi: 10.1016/j.pain.2012.04.029. Epub 2012 May 31.
- Background: PubMed 14678840Arendt-Nielsen L, Chen AC. Lasers and other thermal stimulators for activation of skin nociceptors in humans. Neurophysiol Clin. 2003 Dec;33(6):259-68. doi: 10.1016/j.neucli.2003.10.005.
- Background: PubMed 22560289Martinez V, Ammar SB, Judet T, Bouhassira D, Chauvin M, Fletcher D. Risk factors predictive of chronic postsurgical neuropathic pain: the value of the iliac crest bone harvest model. Pain. 2012 Jul;153(7):1478-1483. doi: 10.1016/j.pain.2012.04.004. Epub 2012 May 2.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Mads U Werner, MD, DMSc principal investigator
Neuroscience Center, Copenhagen University Hospital, Denmark
Ron Kupers, MSc study chair
Panum Institute, Copenhagen University, Denmark
Henrik Kehlet, MD, DMSc study chair
JMC, Copenhagen University Hospital, Denmark
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing CO2-Laser stimulation (Laser Stimulation Device, SIFEC) in people with Healthy Subjects, run by University of Copenhagen at 1 site in Denmark.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 3 Dec 2015. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Denmark. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Changes in distribution of reaction times assessed by laser stimuli in the thermal injury area (the primary hyperalgesia area) comparing post-injury values with pre-injury, baseline values. (time frame: 24 hours). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT02442726, which also lists 16 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Dec 2015.