The effect of minimally invasive sacroiliac joint fusion compared with sham operation: study protocol of a prospective double-blinded multicenter randomized controlled trial

Figures & data

Table 1. Inclusion and exclusion criteria

Inclusion criteria Suspected SIJ pain for > 6 months, or > 18 months for pregnancy-induced pelvic girdle pain Between 21 and 70 years old Diagnosis of the SIJ as the suspected primary pain generator based on both of the following: Pain pointed with a single finger (Fortin Finger Test) at or close to the posterior superior iliac spine (PSIS) with possible radiation into buttocks, posterior thigh, or groin At least 3 of 6 clinical tests for SIJ pain (Laslett et al. 2005, Vleeming et al. 2008) Compression Posterior Pelvic Pain Provocation test—P4 Palpation of the long dorsal sacroiliac ligament Patrick’s FABER test Active Straight Leg Raise (ASLR) test Gaenslen’s test Reduced SIJ pain (NRS) of at least 50% of the pre-injection NRS score after fluoroscopically or computed tomography guided controlled injection of local anesthetic into the SIJ Oswestry Disability Index (ODI) score of at least 30% 6.SIJ pain of at least 5 on the Numeric Rating Scale (NRS), where 0 is no pain at all and 10 is worst imaginable pain Bilateral SIJ pain, if one dominant side. If eligible the dominant painful SIJ will be treated in the study Mentally and physically able to comply with study protocol Signed study-specific informed consent

Exclusion criteria Pain due to other causes, such as lumbar disc degeneration, lumbar disc herniation, lumbar spondylolisthesis, lumbar spinal stenosis, lumbar facet degeneration, and lumbar vertebral body fracture Sacroiliac pathology caused by auto-immune disease (e.g., ankylosing spondylitis), neoplasia, or crystal arthropathy History of recent (< 1 year) fracture of the pelvis with documented malunion, non-union of sacrum or ilium, or any type of internal fixation of the pelvic rig. Spine surgery during the past 12 months Previously diagnosed or suspected osteoporosis (defined as T-score < –2.5 or history of osteoporotic fracture) Documented osteomalacia or other metabolic bone disease Any condition or anatomy that makes treatment with the iFuse Implant System infeasible Patients with prior SIJ surgery

Flow-chart of trial timeline.

Table 2. Timeline of outcome measures

Endpoint/outcome	Baseline	Preoperative	Postoperative	3 months	6 months	12 months	24 months
NRS operated SIJ/side	x	x	x	x	x	x	x
Global NRS	x	x	x	x	x	x	x
NRS nonoperated SIJ/side	x	x	x	x	x	x	x
Leg pain NRS	x	x	x	x	x	x	x
ODI	x	x		x	x	x	x
PGQ	x	x		x	x	x	x
EQ-5D-5L, including EQ-VAS scale	x	x		x	x	x	x
Clinical tests
• Patrick’s test (FABER)
• Posterior Pelvic Pain Provocation test (P4)
• Gaenslen’s test
• Mennell’s test
• Distraction
• Compression
• Palpation of the long dorsal ligament and sacrotuberal ligament	x	x		x	x	x	x
Functional tests
• ASLR
• ASLR range test
• 6MWT
• TUG	x	x		x	x	x	x
Ambulatory and work status	x	x		x	x	x	x
Adverse events ^a			x	x	x	x	x
Re-intervention of target SIJ				x	x	x	x
Patient satisfaction with treatment				x	x	x	x
Patients assessment of treatment				x	x	x	x

a Including device breakage, migration, loosening etc.

SIJ = Sacroiliac joint.

NRS = Numeric Rating Scale (measured on scale 0–10 where 0 is no pain and 10 is worst imaginable pain).

ODI = Oswestry Disability Index (scale 0–100, where 0 is normal function, 100 is bedridden).

PGQ = Pelvic Girdle Questionnaire (score converted to percentage 0–100%, where 0 is worst and 100 is best pelvic health).

EQ-5D-5L: describes quality of life through scores in 5 dimensions all scored from 1 = no problems to 5 = extreme problems.

EQ-VAS (scale from 0–100: where 0 is worst and 100 is best health).

ASLR = Active Straight Leg Raise test (scale 0–5 where 0 = no difficulty raising leg, 5 = severe difficulty. Measured per leg).

ASLR range test = Active Straight Leg Raise Range test (measures how high a straight leg can be raised from examination table to the nearest 5°).

6MWT = 6 minute walking test (measures the distance in m walked in 6 minutes in 1 round).

TUG = Timed Up and Go (measures the time it takes a patient to sit in chair, raise, walk 3 meters back and forth, and sit back in chair. Mean time of 2 rounds is recorded).