An interventional study of pedicle subtraction osteotomy in Ankylosing Spondylitis, sponsored by China-Japan Friendship Hospital. Not yet recruiting. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-12.
Sponsored by China-Japan Friendship Hospital · Not applicable, Interventional, and Treatment
This study is an exploratory self-controlled trial, aiming to preliminarily evaluate the effectiveness and safety of surgical treatment for ankylosing spondylitis.
533 studies on the registry are indexed under Spondylitis, Ankylosing; 99 are open to participants now.
This study's planned enrollment of 35 is below the median of 88 across 303 interventional studies indexed under Spondylitis, Ankylosing.
Browse Spondylitis, Ankylosing studies →China-Japan Friendship Hospital is the lead sponsor of 179 studies on the registry; 112 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Procedure: pedicle subtraction osteotomy
To estimate changes in function and sagittal alignment at 12 months after pedicle subtraction osteotomy.
Change in Bath Ankylosing Spondylitis Functional Index(BASFI) from baseline to 12 months after surgery (ΔBASFI)
on the 0-10 scale. A negative change indicates improved function.
Time frame: at baseline, 6 months, and 12 months
Change in T1 pelvic angle (TPA) from baseline to 12 months after surgery (ΔTPA)
TPA will be measured on the standing lateral full-spine radiograph as the angle between the line connecting the center of the T1 vertebral body to the bicoxofemoral axis and the line connecting the bicoxofemoral axis to the midpoint of the superior endplate of S1. TPA incorporates both global spinal inclination and pelvic retroversion and provides a global measure of sagittal alignment. A negative change indicates improved function.
Time frame: at baseline, 6 months, and 12 months
the seventh cervical vertebra (C7)-sagittal vertical axis(SVA)
Measured on a full-length standing lateral radiograph as the horizontal distance from the C7 plumb line to the posterior-superior corner of the S1 endplate. Unit: millimeters (mm)
Time frame: at baseline, 6 months, and 12 months
spinosacral angle(SSA)
Measured as the angle between the C7 plumb line and the sacral endplate line. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
Sagittal Pelvic Angle(SPA)
Measured as the angle between the sacral endplate line and the line connecting the femoral head axis to the C7 plumb line. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
pelvic incidence(PI)
Measured as the angle between the line perpendicular to the sacral endplate at its midpoint and the line from that midpoint to the femoral head axis. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
pelvic tilt(PT)
Measured as the angle between the vertical line and the line from the femoral head axis to the sacral endplate midpoint. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
sacral slope(SS)
Measured as the angle between the sacral endplate line and the horizontal line. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
Pelvic Incidence(PI)-lumbar lordosis(LL) mismatch
Calculated as PI minus LL. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
global kyphosis(GK)
Measured as the angle between the superior endplate of the upper-most tilted vertebra and the inferior endplate of the lower-most tilted vertebra in the kyphotic segment. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
thoracic kyphosis(TK)
Measured as the Cobb angle between the superior endplate of T4 and the inferior endplate of T12. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
oracolumbar kyphosis(TLK)
Measured as the Cobb angle between the superior endplate of T10 and the inferior endplate of L2. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
lumbar lordosis(LL)
Measured as the Cobb angle between the superior endplate of L1 and the superior endplate of S1. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
Kyphosis apex vertebra
Identified as the vertebra at the apex of the maximal kyphotic curve on the lateral radiograph. Unit: vertebral level (e.g.T8, T9)
Time frame: at baseline, 6 months, and 12 months
Local osteotomy angle
Measured as the angle created at the osteotomy site between the superior and inferior endplates of the resected/adjacent vertebrae on intraoperative or postoperative imaging. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
the second cervical vertebra(C2)-the seventh cervical vertebra(C7) lordosis.
Measured as the Cobb angle between the inferior endplate of C2 and the inferior endplate of C7. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
the second cervical vertebra(C2)-the seventh cervical vertebra(C7) sagittal vertical axis(SVA)
Measured as the horizontal distance from the C2 plumb line (vertical line from the C2 centroid) to the posterior-superior corner of C7. Unit: millimeters (mm)
Time frame: at baseline, 6 months, and 12 months
the first thoracic vertebra(T1) slope
Measured as the angle between the superior endplate of T1 and the horizontal line. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
the first thoracic vertebra(T1) angle
T1 angle measured between the T1 endplate line and the line from the T1 centroid to the C7 centroid. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
Neck tilt
Neck tilt measured as the angle between the vertical line and the line from the sternal notch to the T1 centroid
Time frame: at baseline, 6 months, and 12 months
Coronal Cobb angle
Measured as the Cobb angle between the superior endplate of the upper-end vertebra and the inferior endplate of the lower-end vertebra of the coronal curve. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
Coronal vertical axis
Measured as the horizontal distance from the C7 plumb line to the sacral midline (center of S1). Unit: millimeters (mm)
Time frame: at baseline, 6 months, and 12 months
Pelvic tilt in the coronal plane
Measured as the angle between the horizontal line and the line connecting the bilateral femoral head centers (or the sacral endplate line) on the AP radiograph. Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
proximal junctional kyphosis(PJK)
Measured as the angle between the inferior endplate of the upper instrumented vertebra (UIV) and the superior endplate of the vertebra two levels above the UIV (UIV+2). Unit: degrees (°)
Time frame: at baseline, 6 months, and 12 months
proximal junctional failure(PJF)
Defined by the presence of proximal junctional fracture, implant failure, or revision surgery at the proximal junction. Unit: event (yes/no)
Time frame: at baseline, 6 months, and 12 months
Implant failure
Defined as radiographic evidence of screw/rod breakage, loosening, or pullout. Unit: event (yes/no)
Time frame: at baseline, 6 months, and 12 months
surgical safety outcomes
Recorded as events (yes/no) or continuous measures during the perioperative and follow-up periods, including but not limited to: intraoperative blood loss (mL), operative time (min), length of hospital stay (d), transfusion rate, surgical site/deep infection rate, neurologic deficit, dural tear, deep vein thrombosis/pulmonary embolism, implant failure, revision surgery rate, readmission rate, and mortality. Units: mL / min / d / event (yes/no) / proportion (%). Lower event incidence, less blood loss, and shorter operative time and hospital stay indicate better safety; the converse indicates worse safety. Serious complications (infection, neurologic deficit, implant failure, revision, death) indicate worse safety.
Time frame: at baseline, 6 months, and 12 months
Ankylosing Spondylitis Disease Activity Score based on C-reactive protein(ASDAS-CRP)
Composite score calculated from four patient-reported items (back pain, duration of morning stiffness, patient global assessment, peripheral joint pain/swelling) and serum CRP using a weighted formula. Minimum = 0; maximum = no fixed upper limit (typically \~0-6; theoretical minimum 0). Higher scores indicate worse disease activity; lower scores indicate better disease activity. Cut-offs: \< 1.3 = inactive disease, \< 2.1 = low disease activity, \> 2.1 = high disease activity.
Time frame: at baseline, 6 months, and 12 months
C-reactive protein(CRP)
Measured in peripheral venous blood as serum CRP concentration. Minimum = 0 (cannot be negative); maximum = no fixed upper limit (assay-dependent). Unit: mg/L (or mg/dL). Higher concentrations indicate greater systemic inflammatory burden (worse); lower concentrations indicate less inflammation (better). Normal reference is typically \< 5 mg/L (some laboratories \< 3 mg/L).
Time frame: at baseline, 6 months, and 12 months
Erythrocyte Sedimentation Rate(ESR)
Measured in peripheral venous blood by the Westergren method as the distance erythrocytes fall at the end of 1 hour. Minimum = 0; maximum = no fixed upper limit (assay-dependent). Unit: mm/h (millimeters per hour). Higher values indicate greater inflammatory activity (worse); lower values indicate better status. Reference ranges are age/sex-specific (e.g., \< 15 mm/h in men, \< 20 mm/h in women).
Time frame: at baseline, 6 months, and 12 months
Bath Ankylosing Spondylitis Disease Activity Index(BASDAI)
Derived from six patient-reported items (fatigue, neck/back/hip pain, peripheral joint pain/swelling, enthesitis, severity of morning stiffness, duration of morning stiffness), each scored on a 0-10 numeric rating/visual analogue scale; total = mean of the six items. Minimum = 0; maximum = 10. Unit: 0-10 score (unitless). Higher scores indicate worse disease activity; lower scores indicate better disease activity. Cut-off: \< 4 = low disease activity/well controlled; ≥ 4 = active disease.
Time frame: at baseline, 6 months, and 12 months
36-Item Short Form Health Survey(SF-36)
Thirty-six patient-reported items yield eight domains (Physical Functioning, Role-Physical, Bodily Pain, General Health, Vitality, Social Functioning, Role-Emotional, Mental Health) and two summary scores (Physical Component Summary \[PCS\] and Mental Component Summary \[MCS\]). All domains and summary scores are linearly transformed to a 0-100 scale; minimum = 0, maximum = 100. Unit: 0-100 score (unitless). Higher scores indicate better health-related quality of life; lower scores indicate worse.
Time frame: at baseline, 6 months, and 12 months
Visual Analogue Scale for Pain(VAS)
The patient marks current status on a 100-mm (or 0-10) horizontal/vertical line; the distance from the "none" anchor to the mark is measured. Minimum = 0; maximum = 100 mm (or 0-10). Unit: mm (or 0-10 score, unitless). In ankylosing spondylitis studies, pain VAS (e.g., back pain over the past week) and patient global assessment VAS (e.g., overall disease status over the past week) are typically measured separately and should be reported as distinct constructs. Higher scores indicate worse pain/overall status; lower scores indicate better status.
Time frame: at baseline, 6 months, and 12 months
No study locations are listed for this record.
Start is estimated for Oct 2026; primary completion for Jul 2028, 20 months later.
Of 61 non-industry interventional studies with no phase under Spondylitis, Ankylosing, half reached primary completion within 12 months of starting (the median), counting those still running; a quarter within 7 and three quarters within 20. This study's planned 20 months is above that.
Counting every sponsor, half of 64 studies reached it within 12 months; a quarter within 7 and three quarters within 20.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Nov 2026. You cannot join it, but the record below documents what was studied.
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