Surface Topography and Radiographic Spinal Damage in Radiographic Axial Spondyloarthritis

November 10, 2026 updated by: Seyma Alkan, Ankara Etlik City Hospital

Association Between Static Spinal Posture Assessed by Surface Topography (DIERS) and Radiographic Structural Damage (Modified Stoke Ankylosing Spondylitis Spine Score, mSASSS) in Radiographic Axial Spondyloarthritis: A Cross-Sectional Study

Radiographic axial spondyloarthritis (r-axSpA) causes progressive structural damage of the spine, conventionally quantified on lateral cervical and lumbar radiographs using the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS). Repeated radiography entails cumulative radiation exposure, substantial inter-reader variability and low sensitivity in early disease. DIERS Formetric 4D (four-dimensional) surface topography (DIERS International GmbH, Schlangenbad, Germany) provides radiation-free three-dimensional modelling of the spine and pelvis. The association between sagittal balance and structural damage has been demonstrated with a radiation-based biplanar low-dose radiography system (EOS imaging, Paris, France), but whether a radiation-free topographic method reflects the same association has not been investigated.

This single-centre, cross-sectional observational study will enrol 53 adults with r-axSpA fulfilling the Assessment of SpondyloArthritis international Society (ASAS) criteria with radiographic sacroiliitis according to the modified New York criteria. At a single study visit, static DIERS Formetric 4D measurements, chest expansion, the Bath Ankylosing Spondylitis Metrology Index (BASMI), the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI) and the Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ASDAS-CRP) are obtained. mSASSS is scored by a single reader, blinded to clinical and topographic data, on existing lateral cervical and lumbar radiographs obtained within the preceding 12 months; no additional radiographs are performed for the study. The primary analysis is the correlation between total mSASSS and the DIERS flèche cervicale (cervical sagittal anterior displacement).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Design: single-centre, cross-sectional, non-interventional correlation study in a single patient group; no control group. All participant data are collected in one assessment session lasting approximately 45 to 60 minutes.

Measurements: (a) demographic and anthropometric data; (b) disease duration, age at symptom onset, comorbidities, extra-articular involvement (uveitis, inflammatory bowel disease, psoriasis), human leukocyte antigen B27 (HLA-B27) status, current medication category; (c) radiographic sacroiliitis grade according to the modified New York criteria and the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS; range 0 to 72), scored by a single reader blinded to clinical and topographic data; (d) chest expansion; (e) the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI) and the Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ASDAS-CRP), the latter using routine C-reactive protein values with no additional blood sampling; (f) Bath Ankylosing Spondylitis Metrology Index (BASMI) total score and its five components; (g) DIERS Formetric 4D (four-dimensional) static parameters: flèche cervicale (cervical sagittal anterior displacement, mm), sagittal imbalance (mm and degrees), coronal imbalance (mm), pelvic obliquity (mm), pelvic torsion (degrees), cervical and lumbar depth distance (mm), kyphotic angle (degrees) and lordotic angle (degrees).

Statistical analysis: distribution is assessed with the Shapiro-Wilk test. The primary analysis is a Pearson or Spearman correlation between total mSASSS and flèche cervicale, reported with effect size and 95% confidence interval, followed by multiple linear regression adjusted for age and disease duration. Secondary analyses comprise correlations of DIERS parameters with clinical indices and an exploratory receiver operating characteristic analysis of the ability of DIERS sagittal parameters to predict mSASSS thresholds. The Benjamini-Hochberg procedure is applied to correct for multiple comparisons. Significance is set at p<0.05. Analyses are performed with IBM SPSS Statistics (Statistical Package for the Social Sciences) version 23 or later.

Sample size: calculated with G*Power 3.1.9 for a bivariate normal correlation model, two-tailed, correlation under the null hypothesis (rho H0) = 0, expected effect size r = 0.40, alpha = 0.05 and power = 0.85, giving a required sample of 53 participants (actual power 0.857). The effect size was set conservatively at r = 0.40 rather than the r = 0.61 reported by Wanders et al. (2005) for occiput-to-wall distance versus mSASSS, because DIERS parameters are not identical to clinical mobility measures.

Reporting follows the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
53

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Turkey (Türkiye)
    • Yenimahalle
      • Ankara, Yenimahalle, Turkey (Türkiye), 06560
        • Recruiting
        • Ankara Etlik City Hospital, Department of Physical Medicine and Rehabilitation
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Consecutive patients with radiographic axial spondyloarthritis attending the spondyloarthritis outpatient clinic of the Department of Physical Medicine and Rehabilitation, Ankara Etlik City Hospital.

Description

Inclusion Criteria:

  • Age 18 to 65 years
  • Diagnosis of radiographic axial spondyloarthritis fulfilling the Assessment of SpondyloArthritis international Society (ASAS) criteria, confirmed by radiographic sacroiliitis according to the modified New York criteria
  • Able to provide written informed consent and to complete the assessments
  • Available lateral cervical and lumbar radiographs obtained within the 12 months preceding the DIERS measurement

Exclusion Criteria:

  • Neurological disease affecting balance, posture or gait (for example Parkinson disease, amyotrophic lateral sclerosis, cerebellar or vestibular disorders, history of stroke)
  • History of lower extremity joint arthroplasty (hip or knee)
  • Orthopaedic conditions affecting posture, balance or gait (ununited fracture, previous spinal or lower extremity surgery)
  • Advanced cardiopulmonary disease, active infection or malignancy
  • Pregnancy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: CASE_ONLY
  • Time Perspectives: CROSS_SECTIONAL

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Radiographic axial spondyloarthritis patients

Adults aged 18 to 65 years with radiographic axial spondyloarthritis fulfilling the Assessment of SpondyloArthritis international Society (ASAS) classification criteria with radiographic sacroiliitis according to the modified New York criteria, attending the spondyloarthritis outpatient clinic. All participants undergo a single assessment session including static DIERS Formetric 4D surface topography, chest expansion and clinical indices: Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), Bath Ankylosing Spondylitis Metrology Index (BASMI) and Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ASDAS-CRP). The modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) is scored on existing lateral cervical and lumbar radiographs obtained within the preceding 12 months; no additional radiographs are taken.
Diagnostic test: DIERS Formetric 4D surface topography

Radiation-free three-dimensional assessment of spinal and pelvic surface topography performed once in standing position. No radiation, no contact, no intervention on treatment.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Correlation between total mSASSS and DIERS fleche cervicale
Time Frame: Single assessment session (Day 1); mSASSS scored on radiographs obtained within the 12 months preceding the assessment

Total modified Stoke Ankylosing Spondylitis Spine Score (mSASSS; range 0 to 72, higher scores indicate greater structural damage), correlated with flèche cervicale (cervical sagittal anterior displacement, mm) measured by DIERS Formetric 4D surface topography. Reported as a correlation coefficient with magnitude, direction and 95% confidence interval.
Single assessment session (Day 1); mSASSS scored on radiographs obtained within the 12 months preceding the assessment

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Correlation between DIERS sagittal parameters and BASMI
Time Frame: Single assessment session (Day 1)

Bath Ankylosing Spondylitis Metrology Index (range 0 to 10, higher scores indicate worse spinal mobility) correlated with DIERS Formetric 4D static parameters: fleche cervicale (mm), sagittal imbalance (mm and degrees), coronal imbalance (mm), pelvic obliquity (mm), pelvic torsion (degrees), cervical and lumbar depth distance (mm), kyphotic angle (degrees) and lordotic angle (degrees).
Single assessment session (Day 1)
Correlation between DIERS sagittal parameters and ASDAS-CRP
Time Frame: Single assessment session (Day 1)

Ankylosing Spondylitis Disease Activity Score with C-reactive protein (higher scores indicate greater disease activity) correlated with DIERS Formetric 4D static parameters: fleche cervicale (mm), sagittal imbalance (mm and degrees), coronal imbalance (mm), pelvic obliquity (mm), pelvic torsion (degrees), cervical and lumbar depth distance (mm), kyphotic angle (degrees) and lordotic angle (degrees).
Single assessment session (Day 1)
Correlation between total mSASSS and other DIERS Formetric static parameters
Time Frame: Single assessment session (Day 1); mSASSS scored on radiographs obtained within the 12 months preceding the assessment

Total modified Stoke Ankylosing Spondylitis Spine Score (mSASSS; range 0 to 72, higher scores indicate greater structural damage) correlated with the remaining DIERS Formetric 4D static parameters: sagittal imbalance (mm and degrees), coronal imbalance (mm), pelvic obliquity (mm), pelvic torsion (degrees), cervical depth distance (mm), lumbar depth distance (mm), kyphotic angle (degrees) and lordotic angle (degrees). Reported as correlation coefficients with 95% confidence intervals.
Single assessment session (Day 1); mSASSS scored on radiographs obtained within the 12 months preceding the assessment
Correlation between DIERS sagittal parameters and BASDAI
Time Frame: Single assessment session (Day 1)

Bath Ankylosing Spondylitis Disease Activity Index (range 0 to 10, higher scores indicate greater disease activity) correlated with DIERS Formetric 4D static parameters: flèche cervicale (mm), sagittal imbalance (mm and degrees), coronal imbalance (mm), pelvic obliquity (mm), pelvic torsion (degrees), cervical and lumbar depth distance (mm), kyphotic angle (degrees) and lordotic angle (degrees).
Single assessment session (Day 1)
Correlation between DIERS sagittal parameters and BASFI
Time Frame: Single assessment session (Day 1)

Bath Ankylosing Spondylitis Functional Index (range 0 to 10, higher scores indicate worse physical function) correlated with DIERS Formetric 4D static parameters: flèche cervicale (mm), sagittal imbalance (mm and degrees), coronal imbalance (mm), pelvic obliquity (mm), pelvic torsion (degrees), cervical and lumbar depth distance (mm), kyphotic angle (degrees) and lordotic angle (degrees).
Single assessment session (Day 1)
Correlation between DIERS sagittal parameters and chest expansion
Time Frame: Single assessment session (Day 1)

Chest expansion measured in centimetres correlated with DIERS Formetric 4D static parameters: flèche cervicale (mm), sagittal imbalance (mm and degrees), coronal imbalance (mm), pelvic obliquity (mm), pelvic torsion (degrees), cervical and lumbar depth distance (mm), kyphotic angle (degrees) and lordotic angle (degrees).
Single assessment session (Day 1)
Discriminative performance of DIERS sagittal parameters for mSASSS thresholds
Time Frame: Single assessment session (Day 1); mSASSS scored on radiographs obtained within the 12 months preceding the assessment

Exploratory receiver operating characteristic analysis of DIERS Formetric 4D sagittal parameters for discriminating total modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) thresholds. Reported as area under the curve with 95% confidence interval, sensitivity and specificity.
Single assessment session (Day 1); mSASSS scored on radiographs obtained within the 12 months preceding the assessment

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Ankara Etlik City Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Ajda Bal, Professor of Physical Medicine and Rehabilitation

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 19, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 20, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 20, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 28, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 28, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 2, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 12, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 10, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • AEŞH-BADEK1-2026-909

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared. According to the study protocol, research data are accessible only to the investigators. Aggregate results will be published.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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