Complex Regional Pain SyndromeNCT06798493
CSS-SR Validation Study
An observational study of Complex Regional Pain Syndrome and Pain, run by Hospital for Special Surgery, New York at 1 site in United States.
Trial summary
Complex Regional Pain Syndrome (CRPS) is an orphan condition with no interventions proven effective in large-scale clinical trials. In-person clinical evaluations are required to make a CRPS diagnosis and determine study eligibility, making recruitment for CRPS trials challenging. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Complex Regional Pain Syndrome, Pain
- What is being tested?
- Complex Regional Pain Syndrome (CRPS) Severity Score - Self Report
- How many people
- 100 participants
- Where
- 1 siteUnited States
- Study dates
- 27 Jan 2025to 29 Dec 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
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 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: Hospital for Special Surgery Outpatient Pain Management Patients
Who may be able to join
- 18 years of age or older
- Suspected or diagnosed with unilateral CRPS type I or II of the upper or lower extremity
- Suspected or diagnosed with non-CRPS-related pain of the upper or lower extremities
Who cannot join
- Bilateral CRPS
- Total knee arthroplasty as the inciting event of CRPS
- Less than 18 years of age
- Non-English speaking
- Inability to comprehend study protocol and questionnaires
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site
Hospital for Special Surgery
New York, New York, 10021
About this study
Official title: Validation of the CRPS Severity Score-Self Report
Complex Regional Pain Syndrome (CRPS) is an orphan condition with no interventions proven effective in large-scale clinical trials. In-person clinical evaluations are required to make a CRPS diagnosis and determine study eligibility, making recruitment for CRPS trials challenging. To address this barrier, we will validate a self-report measure of CRPS symptom severity suitable for remote administration that was created by colleagues at Vanderbilt University.
The aim of this study is to evaluate the correspondence at the item and total score level between the proposed self-report measure (CRPS Severity Score-Self Report; CSS-SR) and an existing validated measure of CRPS signs and symptoms derived from clinical history and physical examination data (CSS-Clinician version) and evaluate its diagnostic accuracy relative to clinically determined, criterion-based CRPS diagnosis using the Budapest criteria.
Read the detailed description
Complex Regional Pain Syndrome (CRPS) is a chronic pain condition characterized by spontaneous pain, allodynia and hyperalgesia, edema, vasomotor and sudomotor changes, and motor and trophic changes. It usually begins regionally in a single limb after injury or surgery, and inflammatory, autonomic, and central mechanisms all appear to contribute to differing degrees. There are currently no treatments for CRPS proven effective in large scale clinical trials.
CRPS is considered an orphan condition by the U.S. Food and Drug Administration, and as such, acquiring adequate sample sizes for definitive clinical trials is challenging. One barrier to recruitment into CRPS research studies is the need to conduct in-person evaluations to screen for presence of current CRPS clinical features and determine CRPS diagnostic status. Unlike conditions such as chronic low back pain, which can be identified with high accuracy based on questions that can be administered remotely (i.e., pain intensity, location, frequency, and impact), diagnosing CRPS using the 2012 International Association for the Study of Pain (IASP) criteria (i.e., the Budapest criteria) requires that a history and physical examination be conducted. This situation is similar to that formerly encountered in fibromyalgia studies prior to publication of the modified American College of Rheumatology 2010 criteria (i.e., diagnosis was based on clinical tender point evaluation), a barrier ultimately overcome by publication of the validated 2010 self-report diagnostic screening criteria that could be administered remotely.
Our collaborators developed a self-report measure suitable for remote delivery to assess CRPS-related symptoms. They evaluated the diagnostic accuracy of a self-report version of the CRPS Severity Score (CSS-SR) and assessed its validity relative to the original CSS based on clinician evaluation (CSS-Clinician) in 112 patients undergoing total knee arthroplasty (TKA). In this study we will recruit patients with pain in an extremity at the outpatient chronic pain clinic at 75th street and will ask patients to complete the CSS-SR while the clinician evaluates the participant against the Budapest CRPS diagnosis criteria per usual care. Data (no identifiers) will be shared with our collaborator who will analyze and combine the findings from his TKA cohort with our outpatient chronic pain cohort to understand the external validity of the CSS-SR.
The proposed content of the self-report version of the CSS (CSS-SR) was rationally developed by creating lay language items designed to parallel the diagnostic symptoms assessed in the standardized clinician-obtained history that provides the basis for the symptom component of the CSS-Clinician. Thirteen questions in yes/no (presence/absence) checklist format assess presence of symptoms in the following areas: more prolonged or severe pain than expected, allodynia/hyperalgesia, skin temperature changes, skin color changes, edema, sweating changes, trophic changes (skin, hair, nails), tremor, dystonia, weakness, and range of motion limitations.
Scoring of the CSS-SR parallels scoring of the CSS-Clinician, with items coded as 1 for "Yes" and 0 for "No", with responses summed to create a total CSS-SR score potentially ranging from 0-13.
For the current validation study, CSS-SR items referred specifically to the "affected limb" to ensure that participants describe symptoms in the same body region as reflected in the assessment used to derive the CSS-Clinician.
- Conditions
- Complex Regional Pain Syndrome, Pain
- Being tested
- Complex Regional Pain Syndrome (CRPS) Severity Score - Self Report
- Keywords
- CRPS, Complex Regional Pain Syndrome, self-report, Complex Regional Pain Syndrome Severity Score (CSS)
- Medical subject headings
- Complex Regional Pain Syndromes, Pain
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Complex Regional Pain Syndrome (CRPS) Severity Score - Self ReportOther
Self-report tool in a questionnaire format to capture CPRS Severity Score.
| Study group | Role | What they receive |
|---|---|---|
| CRPS group | Patients suspected or diagnosed with unilateral CRPS type I or II of the upper or lower extremity Receives: Other: Complex Regional Pain Syndrome (CRPS) Severity Score - Self Report | |
| Non-CRPS group | Patients suspected or diagnosed with non-CRPS-related pain of the upper or lower extremities Receives: Other: Complex Regional Pain Syndrome (CRPS) Severity Score - Self Report |
What is being measured
The primary outcome is the main question the study is designed to answer.
Concordance between CSS-Clinician and CSS-SR total scores
Concordance between CSS-Clinician total scores, which will be on a numerical scale potentially ranging from 0-16, and CSS-SR total scores, which will be on a numerical scale potentially ranging from 0-13. Higher scores indicate greater CRPS symptom severity while lower scores indicate a lesser degree of symptom severity. Concordance (corrected for chance agreement) between CSS-Clinician and CSS-SR items and total scores will be assessed using intraclass correlations (ICCs; two-way random effects model; potential range = -1.00 to 1.00). Strength of agreement will be evaluated for descriptive purposes based on published recommendations: < 0.50 = poor agreement, 0.50 - 0.75 = moderate agreement, 0.76 - 0.90 = good agreement, and >0.90 = excellent agreement. All analyses will use the maximum number of cases available with a two-sided p<0.05 criterion for statistical significance.
Measured: Date of enrollment
Secondary outcomes (1)
Diagnostic accuracy relative to clinically-determined, criterion-based CRPS diagnosis using the Budapest criteria
Rates of CRPS diagnoses on both the CSS-Clinician and CSS-SR will be summarized as frequencies of positive and negative diagnoses.
Cut scores on the CSS-SR for use in determining its accuracy as a screening tool for predicting dichotomous criterion-based CRPS diagnosis will be generated by inspection of receiver operating characteristic (ROC) curves and associated sensitivity/specificity values. All analyses will use the maximum number of cases available with a two-sided p<0.05 criterion for statistical significance.
Measured: Date of enrollment
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Jan 2025
- Study start27 Jan 2025
- Primary completion29 Dec 2026 (estimated)
- Study completion29 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Complex Regional Pain SyndromeStudies of the same condition, open and under way.
- 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
- Observational
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Hospital for Special Surgery, New York
- Sponsor type
- University, hospital or other
- Collaborators
- Vanderbilt University
- Responsible party
- Sponsor
- Investigators
- Alexandra Sideris, PhD, Principal investigator, Hospital for Special Surgery, New York
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06798493
- Sponsor's protocol ID
- 2024-1529
- Status last verified
- Jan 2026
- First submitted
- 22 Jan 2025
- Last updated
- 13 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: The data sharing plan will be finalized with our collaborators at study completion.
Publications
Wolfe F, Clauw DJ, Fitzcharles MA, Goldenberg DL, Hauser W, Katz RS, Mease P, Russell AS, Russell IJ, Winfield JB. Fibromyalgia criteria and severity scales for clinical and epidemiological studies: a modification of the ACR Preliminary Diagnostic Criteria for Fibromyalgia. J Rheumatol. 2011 Jun;38(6):1113-22. doi: 10.3899/jrheum.100594. Epub 2011 Feb 1.
PubMed 21285161Deyo RA, Dworkin SF, Amtmann D, Andersson G, Borenstein D, Carragee E, Carrino J, Chou R, Cook K, DeLitto A, Goertz C, Khalsa P, Loeser J, Mackey S, Panagis J, Rainville J, Tosteson T, Turk D, Von Korff M, Weiner DK. Report of the NIH Task Force on research standards for chronic low back pain. J Pain. 2014 Jun;15(6):569-85. doi: 10.1016/j.jpain.2014.03.005. Epub 2014 Apr 29.
PubMed 24787228Bruehl S. An update on the pathophysiology of complex regional pain syndrome. Anesthesiology. 2010 Sep;113(3):713-25. doi: 10.1097/ALN.0b013e3181e3db38.
PubMed 20693883
Study at a glance
From the registry record, last updated by the sponsor on 13 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Validation of the CRPS Severity Score-Self Report
- ClinicalTrials.gov ID
- NCT06798493
- Acronym / sponsor ID
- 2024-1529
- Conditions
- Complex Regional Pain Syndrome, Pain
- Keywords
- CRPS, Complex Regional Pain Syndrome, self-report, Complex Regional Pain Syndrome Severity Score (CSS)
- Study type
- Observational
- Recruitment status
- Enrolling by invitation
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Hospital for Special Surgery, New YorkUniversity, hospital or other
- Collaborators
- Vanderbilt University
- Study start
- 27 Jan 2025 (actual)
- Primary completion
- 29 Dec 2026 (estimated)
- Study completion
- 29 Dec 2026 (estimated)
- First posted
- 29 Jan 2025 (actual)
- 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.
Complex Regional Pain Syndrome (CRPS) is an orphan condition with no interventions proven effective in large-scale clinical trials. In-person clinical evaluations are required to make a CRPS diagnosis and determine study eligibility, making recruitment for CRPS trials challenging. To address this barrier, we will validate a self-report measure of CRPS symptom severity suitable for remote administration that was created by colleagues at Vanderbilt University.
The aim of this study is to evaluate the correspondence at the item and total score level between the proposed self-report measure (CRPS Severity Score-Self Report; CSS-SR) and an existing validated measure of CRPS signs and symptoms derived from clinical history and physical examination data (CSS-Clinician version) and evaluate its diagnostic accuracy relative to clinically determined, criterion-based CRPS diagnosis using the Budapest criteria.
Detailed description
Complex Regional Pain Syndrome (CRPS) is a chronic pain condition characterized by spontaneous pain, allodynia and hyperalgesia, edema, vasomotor and sudomotor changes, and motor and trophic changes. It usually begins regionally in a single limb after injury or surgery, and inflammatory, autonomic, and central mechanisms all appear to contribute to differing degrees. There are currently no treatments for CRPS proven effective in large scale clinical trials.
CRPS is considered an orphan condition by the U.S. Food and Drug Administration, and as such, acquiring adequate sample sizes for definitive clinical trials is challenging. One barrier to recruitment into CRPS research studies is the need to conduct in-person evaluations to screen for presence of current CRPS clinical features and determine CRPS diagnostic status. Unlike conditions such as chronic low back pain, which can be identified with high accuracy based on questions that can be administered remotely (i.e., pain intensity, location, frequency, and impact), diagnosing CRPS using the 2012 International Association for the Study of Pain (IASP) criteria (i.e., the Budapest criteria) requires that a history and physical examination be conducted. This situation is similar to that formerly encountered in fibromyalgia studies prior to publication of the modified American College of Rheumatology 2010 criteria (i.e., diagnosis was based on clinical tender point evaluation), a barrier ultimately overcome by publication of the validated 2010 self-report diagnostic screening criteria that could be administered remotely.
Our collaborators developed a self-report measure suitable for remote delivery to assess CRPS-related symptoms. They evaluated the diagnostic accuracy of a self-report version of the CRPS Severity Score (CSS-SR) and assessed its validity relative to the original CSS based on clinician evaluation (CSS-Clinician) in 112 patients undergoing total knee arthroplasty (TKA). In this study we will recruit patients with pain in an extremity at the outpatient chronic pain clinic at 75th street and will ask patients to complete the CSS-SR while the clinician evaluates the participant against the Budapest CRPS diagnosis criteria per usual care. Data (no identifiers) will be shared with our collaborator who will analyze and combine the findings from his TKA cohort with our outpatient chronic pain cohort to understand the external validity of the CSS-SR.
The proposed content of the self-report version of the CSS (CSS-SR) was rationally developed by creating lay language items designed to parallel the diagnostic symptoms assessed in the standardized clinician-obtained history that provides the basis for the symptom component of the CSS-Clinician. Thirteen questions in yes/no (presence/absence) checklist format assess presence of symptoms in the following areas: more prolonged or severe pain than expected, allodynia/hyperalgesia, skin temperature changes, skin color changes, edema, sweating changes, trophic changes (skin, hair, nails), tremor, dystonia, weakness, and range of motion limitations.
Scoring of the CSS-SR parallels scoring of the CSS-Clinician, with items coded as 1 for "Yes" and 0 for "No", with responses summed to create a total CSS-SR score potentially ranging from 0-13.
For the current validation study, CSS-SR items referred specifically to the "affected limb" to ensure that participants describe symptoms in the same body region as reflected in the assessment used to derive the CSS-Clinician.
Study design
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| CRPS group | – | Other: Complex Regional Pain Syndrome (CRPS) Severity Score - Self ReportPatients suspected or diagnosed with unilateral CRPS type I or II of the upper or lower extremity |
| Non-CRPS group | – | Other: Complex Regional Pain Syndrome (CRPS) Severity Score - Self ReportPatients suspected or diagnosed with non-CRPS-related pain of the upper or lower extremities |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Hospital for Special Surgery Outpatient Pain Management Patients
Key inclusion criteria (3 listed)
- 18 years of age or older
- Suspected or diagnosed with unilateral CRPS type I or II of the upper or lower extremity
- Suspected or diagnosed with non-CRPS-related pain of the upper or lower extremities
Key exclusion criteria (5 listed)
- Bilateral CRPS
- Total knee arthroplasty as the inciting event of CRPS
- Less than 18 years of age
- Non-English speaking
- Inability to comprehend study protocol and questionnaires
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 |
|---|---|---|
| Complex Regional Pain Syndrome (CRPS) Severity Score - Self ReportSelf-report tool in a questionnaire format to capture CPRS Severity Score. | Other | CRPS group, Non-CRPS group |
Primary outcome
Concordance between CSS-Clinician and CSS-SR total scores
Time frame: Date of enrollment
Concordance between CSS-Clinician total scores, which will be on a numerical scale potentially ranging from 0-16, and CSS-SR total scores, which will be on a numerical scale potentially ranging from 0-13. Higher scores indicate greater CRPS symptom severity while lower scores indicate a lesser degree of symptom severity. Concordance (corrected for chance agreement) between CSS-Clinician and CSS-SR items and total scores will be assessed using intraclass correlations (ICCs; two-way random effects model; potential range = -1.00 to 1.00). Strength of agreement will be evaluated for descriptive purposes based on published recommendations: < 0.50 = poor agreement, 0.50 - 0.75 = moderate agreement, 0.76 - 0.90 = good agreement, and >0.90 = excellent agreement. All analyses will use the maximum number of cases available with a two-sided p<0.05 criterion for statistical significance.
1 secondary outcome
Diagnostic accuracy relative to clinically-determined, criterion-based CRPS diagnosis using the Budapest criteria
Time frame: Date of enrollment
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Feb 2026.
- Background: PubMed 21285161Wolfe F, Clauw DJ, Fitzcharles MA, Goldenberg DL, Hauser W, Katz RS, Mease P, Russell AS, Russell IJ, Winfield JB. Fibromyalgia criteria and severity scales for clinical and epidemiological studies: a modification of the ACR Preliminary Diagnostic Criteria for Fibromyalgia. J Rheumatol. 2011 Jun;38(6):1113-22. doi: 10.3899/jrheum.100594. Epub 2011 Feb 1.
- Background: PubMed 24787228Deyo RA, Dworkin SF, Amtmann D, Andersson G, Borenstein D, Carragee E, Carrino J, Chou R, Cook K, DeLitto A, Goertz C, Khalsa P, Loeser J, Mackey S, Panagis J, Rainville J, Tosteson T, Turk D, Von Korff M, Weiner DK. Report of the NIH Task Force on research standards for chronic low back pain. J Pain. 2014 Jun;15(6):569-85. doi: 10.1016/j.jpain.2014.03.005. Epub 2014 Apr 29.
- Background: PubMed 20693883Bruehl S. An update on the pathophysiology of complex regional pain syndrome. Anesthesiology. 2010 Sep;113(3):713-25. doi: 10.1097/ALN.0b013e3181e3db38.
- Individual participant dataSharing planned: Undecided. The data sharing plan will be finalized with our collaborators at study completion.
Related trials for Complex Regional Pain Syndrome
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CRPS (Complex Regional Pain Syndromes)
RecruitingPhase 3
Phase 3, Open-Label Extension Study of AMBTX-01 (Neridronate) for Complex Regional Pain Syndrome Type 1
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Active, not recruiting
Transcranial Magnetic Stimulation for Chronic Neuropathic Pain
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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.
Alexandra Sideris, PhD principal investigator
Hospital for Special Surgery, New York
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Complex Regional Pain Syndrome and Pain, run by Hospital for Special Surgery, New York at 1 site in United States.
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 3 inclusion and 5 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: enrolling by invitation, as of the sponsor's last update on 13 Feb 2026. 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 United States. 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. 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?
This study is still under way. Results are not available in the source record yet.
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?
Concordance between CSS-Clinician and CSS-SR total scores (time frame: Date of enrollment). 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 NCT06798493, which also lists 3 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 13 Feb 2026.