Investigation of Sacroiliac Fusion Treatment (INSITE)

INSITE Investigation of Sacroiliac Fusion Treatment

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT01681004

Acronym

INSITE

Enrollment

159

Registered

2012-09-07

Start date

2012-09-30

Completion date

2017-06-30

Last updated

2017-08-25

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Degenerative Sacroiliitis, Sacroiliac Joint Disruption

Keywords

si joint, si joint pain, si joint injury, si joint treatment, si joint injections, si joint inflammation, si joint problems, si joint symptoms, hypermobile si joint, si joint arthritis, si joint pain treatment, inflamed si joint, si joint sclerosis, locked si joint, si joint injuries, si joint disease, si joint infection, sacroiliac joint pelvic pain, sacroiliac joint arthritis treatment

Brief summary

The purpose of this study is to compare outcomes when patients with degenerative sacroiliitis (arthritis of the SI joint) and or sacroiliac disruption (abnormal separation or tearing of the sacroiliac joint)undergo either SI joint fusion with the iFuse Implant System or undergo specific, targeted non-surgical treatment of the SI joint.

Detailed description

The intended analysis was to examine differences in responses at 6 months. It was acknowledged that subjects with chronic pain in the NSM arm group might not experience any benefit as there was little evidence at the time that NSM was helpful. The protocol included optional crossover to other treatments, including surgical treatment. The protocol anticipated a high crossover rate and therefore did not include any comparative analyses after month 6.

Interventions

DEVICEiFuse Implant System

Placement of iFuse implant system via surgery

OTHERNon-surgical management

Medications for pain, physical therapy, SI joint injection and RF ablation

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Masking

NONE

Intervention model description

Parallel group randomized controlled trial

Eligibility

Sex/Gender

ALL

Age

21 Years to 70 Years

Healthy volunteers

Inclusion criteria

1. Age 21-70 at time of screening 2. Patient has lower back pain for \>6 months inadequately responsive to conservative care 3. Diagnosis of sacroiliac joint disruption or degenerative sacroiliitis based on ALL of the following: 1. Patient has pain at or close to the posterior superior iliac spine (PSIS) with possible radiation into buttocks, posterior thigh or groin and can point with a single finger to the location of pain (Fortin Finger Test), and 2. Patient has at least 3 of 5 physical examination maneuvers specific for the SI joint (see Table 3), and 3. Patient has improvement in lower back pain numeric rating scale (NRS) of at least 50% after injection of local anesthetic into affected SI joint(s) (see Section 3.6.4), and 4. One or more of the following: i. SI joint disruption: * Asymmetric SI joint widening on X-ray or CT scan, or * Leakage of contrast on diagnostic arthrography ii. Degenerative sacroiliitis: * Radiographic evidence of SI joint degeneration, including sclerosis, osteophytes, subchondral cysts, or vacuum phenomenon on CT or plain film, or * Due to prior lumbosacral spine fusion 4. Baseline Oswestry Disability Index (ODI) score of at least 30% 5. Baseline SI joint pain score of at least 50 on 0-100 mm visual analog scale\* 6. Patient has signed study-specific informed consent form 7. Patient has the necessary mental capacity to participate and is physically able to comply with study protocol requirements

Exclusion criteria

1. Severe back 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\*\* 2. Other known sacroiliac pathology such as: 1. Sacral dysplasia 2. Inflammatory sacroiliitis (e.g., ankylosing spondylitis or other HLA-associated spondyloarthropathy) 3. Tumor 4. Infection 5. Acute fracture 6. Crystal arthropathy 3. History of recent (\<1 year) major trauma to pelvis 4. Previously diagnosed osteoporosis (defined as prior T-score \<-2.5 or history of osteoporotic fracture). Patients meeting the osteoporosis screening criteria identified by the National Osteoporosis Foundation should be screened for osteoporosis with DEXA.\*\*\*\* See Section 3.6.4. 5. Osteomalacia or other metabolic bone disease 6. Chronic rheumatologic condition (e.g., rheumatoid arthritis) 7. Any condition or anatomy that makes treatment with the iFuse Implant System infeasible 8. Chondropathy 9. Known allergy to titanium or titanium alloys 10. Use of medications known to have detrimental effects on bone quality and soft-tissue healing 11. Prominent neurologic condition that would interfere with physical therapy 12. Current local or systemic infection that raises the risk of surgery 13. Patient currently receiving or seeking worker's compensation, disability remuneration, and/or involved in injury litigation. 14. Currently pregnant or planning pregnancy in the next 2 years 15. Patient is a prisoner or a ward of the state. 16. Known or suspected drug or alcohol abuse\*\*\* 17. Diagnosed psychiatric disease (e.g., schizophrenia, major depression, personality disorders) that could interfere with study participation 18. Patient is participating in an investigational study or has been involved in an investigational study within 3 months prior to evaluation for participation

Design outcomes

Primary

Measure	Time frame	Description
Subject Success	6 months	Composite endpoint of reduction from baseline in VAS back pain score by at least 20 mm, lack of device-related serious adverse events, absence of neurologic worsening and absence of surgical re-intervention. Note that the primary endpoint analysis is \\intent to treat\\, meaning that an outcome (success or failure) is assigned to all subjects randomized and treated. Subjects who withdrew early were deemed study failures.

Secondary

Measure	Time frame	Description
Improvement in Si Joint Pain VAS Score at 3 Months	3 Months	Improvement in SI joint pain VAS score of greater than or equal to 20 points, at post-operative & NSM visits after 3 months. The Visual Analog Scale (VAS) is a 100 mm line on which the subject indicates their level of pain. 0 = no pain. 100 = worst imaginable pain. Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.
Improvement in SI Joint Pain VAS Score at 6 Months	6 Months	Improvement in SI joint pain VAS score of greater than or equal to 20 points, at post-operative & NSM visits after 6 months. The Visual Analog Scale (VAS) is a 100 mm line on which the subject indicates their level of pain. 0 = no pain. 100 = worst imaginable pain. Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.
Improvement in SI Joint Pain VAS Score at 12 Months	12 Months	Improvement in SI joint pain VAS score of greater than or equal to 20 points compared to baseline. The Visual Analog Scale (VAS) is a 100 mm line on which the subject indicates their level of pain. 0 = no pain. 100 = worst imaginable pain. Note that secondary endpoint analysis is based on available data only. Subjects in the NSM group who crossed over are considered failures for this endpoint by definition.
Improvement in SI Joint Pain VAS Score at 24 Months	24 Months	Improvement in SI joint pain VAS score of greater than or equal to 20 points compared to baseline. The Visual Analog Scale (VAS) is a 100 mm line on which the subject indicates their level of pain. 0 = no pain. 100 = worst imaginable pain. Note that secondary endpoint analysis is based on available data only. Subjects in the NSM group who crossed over are considered failures for this endpoint by definition.
Improvement in Back Dysfunction	1 month	Improvement in ODI score of greater than or equal to 15 points, at month 1. Oswestry Disability Index is a validated measure of disability related to low back pain. There are 10 sections, each with a score between 0-5. Scores are expressed on a percent basis without using the percent term. Scores range from 0 (no disability) to 100 (completely disabled). Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.
Improvement in SI Joint Pain VAS Score at 1 Month	1 month	Improvement in SI joint pain VAS score of greater than or equal to 20 points, at post-operative & NSM visit after 1 month. The Visual Analog Scale (VAS) is a 100 mm line on which the subject indicates their level of pain. 0 = no pain. 100 = worst imaginable pain. Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.
Improvement in Quality of Life (QOL) as Measured by EQ-5D (EuroQol-5D) at Post-operative Visits	6 months	Improvement in quality of life (QOL) as measured by EQ-5D (EuroQol-5D) at post-operative visits. EQ-5D is a five-question broad quality of life measure that can be combined into a single index and represents the time trade-off (TTO) utility of current health. A score of 0 would = worst imaginable health, while a score of 1.0 would be best imaginable health. Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.
Ambulatory Status	24 months (surgical group), 6 months (non-surgical group)	Time to full ambulation among those without full ambulation at baseline. 60 days was the median of time to full ambulation for the iFuse implant System arm.
Work Status	1 month	Proportion of non-working (due to back pain or other reasons) subjects who return to work Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.
Number of Participants With Serious Adverse Events (SAEs)	Procedure, discharge, 1, 3, 6, 12, 18 and 24 months	Any event meeting ISO 14155 definition for serious adverse event at following time points: during procedure (if randomized to iFuse), hospital discharge (if iFuse, typically 1-2 days), and 1, 3, 6, 12, 18 and 24 months after randomization.
Improvement in Quality of Life (QOL) as Measured by SF-36 PCS (Physical Component) at Post-operative Visits	6 months	Improvement in quality of life (QOL) as measured by SF-36 PCS (Physical Component) at post-operative / NSM visits. The Short Form 36 health survey (SF-36) is a 36-item patient reported health questionnaire to measure quality of life across 8 domains. The PCS is the Physical Component Summary score. PCS is normed, so that normal scores are 50 +- 10. Higher scores indicate higher quality of life; lower scores indicate lower quality of life. SF-36 PCS (NBS, 2009 norms) ranges from 5 (minimum value, poor physical function) to 80 (maximum, excellent clinical function). Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.

Countries

United States

Participant flow

Pre-assignment details

Of the 442 patients who were screened for participation at 19 sites, 159 (37.8%) were enrolled. Eleven subjects withdrew before treatment (1 before randomization and 10 after randomization but before any treatment was performed), yielding a total of 148 subjects who were enrolled, randomized and treated.

Participants by arm

Arm	Count
iFuse Implant System Surgical placement of iFuse implants in the affected SI joint iFuse Implant System: Placement of iFuse implant system via surgery	102
Non-Surgical Management Medications, SI joint injection, physical therapy and RF ablation of SI joint Non-surgical management: Medications for pain, physical therapy, SI joint injection and RF ablation Subjects were allowed to cross over to other treatments (including surgical treatments) after the month 6 visit was complete.	46
Total	148

Withdrawals & dropouts

Period	Reason	FG000	FG001
Primary Endpoint: 6 Months	Withdrawal by Subject	1	2
Study Completion	Death	1	1
Study Completion	Lost to Follow-up	8	3
Study Completion	Physician Decision	1	3
Study Completion	Site Termination	2	1

Baseline characteristics

Characteristic	Non-Surgical Management	iFuse Implant System	Total
Age, Categorical <=18 years	0 Participants	0 Participants	0 Participants
Age, Categorical >=65 years	8 Participants	10 Participants	18 Participants
Age, Categorical Between 18 and 65 years	38 Participants	92 Participants	130 Participants
Ambulatory without assistance	41 Participants	89 Participants	130 Participants
Body Mass Index, mean (range)	30.6 kg / m2	30.4 kg / m2	30.43 kg / m2
EQ-5D Health Thermometer	57.8 units on a scale STANDARD_DEVIATION 22.9	53.2 units on a scale STANDARD_DEVIATION 23.8	54.6 units on a scale STANDARD_DEVIATION 23.5
EQ-5D Time trade-off (TTO) score	0.47 units on a scale STANDARD_DEVIATION 0.19	0.44 units on a scale STANDARD_DEVIATION 0.18	0.45 units on a scale STANDARD_DEVIATION 0.18
ODI score, mean	56.0 units on a scale STANDARD_DEVIATION 14	57.2 units on a scale STANDARD_DEVIATION 12.8	56.8 units on a scale STANDARD_DEVIATION 13.2
Pain Syndrome Groin pain	29 Participants	60 Participants	89 Participants
Pain Syndrome Pain began peripartum	19 Participants	29 Participants	48 Participants
Pain Syndrome Pain radiates down leg	41 Participants	89 Participants	130 Participants
Pain Syndrome Pain worse with climbing stairs	41 Participants	93 Participants	134 Participants
Pain Syndrome Pain worse with descending stairs	37 Participants	82 Participants	119 Participants
Pain Syndrome Pain worse with rising	41 Participants	88 Participants	129 Participants
Pain Syndrome Pain worse with sitting	41 Participants	89 Participants	130 Participants
Pain Syndrome Pain worse with walking	42 Participants	87 Participants	129 Participants
Participants with hip diagnosis (n, %)	3 Participants	16 Participants	19 Participants
Participants with lumbar stenosis	7 Participants	15 Participants	22 Participants
Participants with sacral trauma (n, %)	3 Participants	8 Participants	11 Participants
Prior Lumbar fusion (n, %)	17 Participants	41 Participants	58 Participants
Prior treatments Physical therapy	36 Participants	71 Participants	107 Participants
Prior treatments RF ablation	4 Participants	21 Participants	25 Participants
Prior treatments Steroid SIJ injection	42 Participants	85 Participants	127 Participants
Race/Ethnicity, Customized American Indian	0 Participants	1 Participants	1 Participants
Race/Ethnicity, Customized Black	2 Participants	3 Participants	5 Participants
Race/Ethnicity, Customized Ethnicity: Hispanic or Latino	4 Participants	4 Participants	8 Participants
Race/Ethnicity, Customized Other	0 Participants	1 Participants	1 Participants
Race/Ethnicity, Customized White	44 Participants	97 Participants	141 Participants
Sex: Female, Male Female	28 Participants	75 Participants	103 Participants
Sex: Female, Male Male	18 Participants	27 Participants	45 Participants
SF-36, mean Mental component summary (MCS)	43.3 units on a scale STANDARD_DEVIATION 12.1	43.0 units on a scale STANDARD_DEVIATION 11.5	43.1 units on a scale STANDARD_DEVIATION 11.6
SF-36, mean Physical component summary (PCS)	30.8 units on a scale STANDARD_DEVIATION 6.2	30.2 units on a scale STANDARD_DEVIATION 6.2	30.4 units on a scale STANDARD_DEVIATION 6.2
Smoking Status (n, %) Current Smoker	3 participants	26 participants	29 participants
Smoking Status (n, %) Former Smoker	13 participants	30 participants	43 participants
Smoking Status (n, %) Never smoker	30 participants	46 participants	76 participants
Taking opiods	29 Participants	70 Participants	99 Participants
Underlying diagnosis Degenerative sacroiliitis	40 Participants	88 Participants	128 Participants
Underlying diagnosis Sacroiliac joint disruption	6 Participants	14 Participants	20 Participants
VAS SIJ pain score, mean	82.2 units on a scale STANDARD_DEVIATION 9.9	82.3 units on a scale STANDARD_DEVIATION 11.9	82.3 units on a scale STANDARD_DEVIATION 11.3
Work status (n, %) Not working due to back pain	8 Participants	20 Participants	28 Participants
Work status (n, %) Not working other reason	4 Participants	6 Participants	10 Participants
Work status (n, %) Not working, retired	9 Participants	21 Participants	30 Participants
Work status (n, %) Not working, student	0 Participants	1 Participants	1 Participants
Work status (n, %) Working full time	21 Participants	45 Participants	66 Participants
Work status (n, %) Working part time	4 Participants	9 Participants	13 Participants
Years of pain, mean (range)	5.0 years	7.0 years	6.0 years

Adverse events

Event type	EG000 affected / at risk	EG001 affected / at risk
deaths Total, all-cause mortality	1 / 102	1 / 46
other Total, other adverse events	69 / 102	35 / 46
serious Total, serious adverse events	38 / 102	12 / 46

Outcome results

Primary

Subject Success

Composite endpoint of reduction from baseline in VAS back pain score by at least 20 mm, lack of device-related serious adverse events, absence of neurologic worsening and absence of surgical re-intervention. Note that the primary endpoint analysis is \*\*intent to treat\*\*, meaning that an outcome (success or failure) is assigned to all subjects randomized and treated. Subjects who withdrew early were deemed study failures.

Time frame: 6 months

Population: A modified intent-to-treat approach was used.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
iFuse Implant System	Subject Success	84 Participants
Non-Surgical Management	Subject Success	12 Participants

Secondary

Ambulatory Status

Time to full ambulation among those without full ambulation at baseline. 60 days was the median of time to full ambulation for the iFuse implant System arm.

Time frame: 24 months (surgical group), 6 months (non-surgical group)

Population: Number of days to full ambulation among those without full ambulation at baseline. At baseline only 13 in the surgical arm were not Ambulatory without assistance and for the NSM group, it was only 5 at baseline.

Arm	Measure	Value (MEDIAN)
iFuse Implant System	Ambulatory Status	60 Days, median
Non-Surgical Management	Ambulatory Status	NA Days, median

Secondary

Improvement in Back Dysfunction

Improvement in ODI score of greater than or equal to 15 points compared to baseline. Oswestry Disability Index is a validated measure of disability related to low back pain. Subjects in the NSM group who crossed over are considered failures for this endpoint by definition.

Time frame: 12 Months

Population: 2 iFuse subjects did not complete ODI at month 12. ODI analysis is not valid in NSM group at 12 months because of high crossover.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
iFuse Implant System	Improvement in Back Dysfunction	72 Participants
Non-Surgical Management	Improvement in Back Dysfunction	NA Participants

Secondary

Improvement in Back Dysfunction

Improvement in ODI score of greater than or equal to 15 points, at month 3. Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.

Time frame: 3 Months

Population: 2 iFuse subjects and 3 NSM subjects did not complete ODI at month 3.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
iFuse Implant System	Improvement in Back Dysfunction	72 Participants
Non-Surgical Management	Improvement in Back Dysfunction	13 Participants

Secondary

Improvement in Back Dysfunction

Improvement in ODI score of greater than or equal to 15 points, at post-operative visits. 6 month visit. Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.

Time frame: 6 Months

Population: 1 iFuse and 2 NSM subjects did not complete ODI at month 6.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
iFuse Implant System	Improvement in Back Dysfunction	74 Participants
Non-Surgical Management	Improvement in Back Dysfunction	6 Participants

Secondary

Improvement in Back Dysfunction

Time frame: 24 Months

Population: The Count of participants = number of subjects that had a threshold change in ODI score of greater than or equal to 15 points. Overall number of participants = number of subjects analyzed. Of the 102, a total of 13 iFuse Implant subjects exited the study and 1 did not complete the ODI survey. By 6 months, 39 NSM subjects crossed over to surgical.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
iFuse Implant System	Improvement in Back Dysfunction	60 Participants
Non-Surgical Management	Improvement in Back Dysfunction	NA Participants

Secondary

Improvement in Back Dysfunction

Improvement in ODI score of greater than or equal to 15 points, at month 1. Oswestry Disability Index is a validated measure of disability related to low back pain. There are 10 sections, each with a score between 0-5. Scores are expressed on a percent basis without using the percent term. Scores range from 0 (no disability) to 100 (completely disabled). Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.

Time frame: 1 month

Population: 2 iFuse and 1 NSM subjects did not complete ODI at 1 month

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
iFuse Implant System	Improvement in Back Dysfunction	49 Participants
Non-Surgical Management	Improvement in Back Dysfunction	6 Participants

Secondary

Improvement in Quality of Life (QOL) as Measured by EQ-5D (EuroQol-5D) at Post-operative Visits

Improvement in quality of life (QOL) as measured by EQ-5D (EuroQol-5D) at post-operative visits. EQ-5D is a five-question broad quality of life measure that can be combined into a single index and represents the time trade-off (TTO) utility of current health. A score of 0 would = worst imaginable health, while a score of 1.0 would be best imaginable health. Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.

Time frame: 12 Months

Population: 2 iFuse subjects did not complete the survey at month 12. Due to high crossover rate to surgery, analysis in the NSM group is not valid.

Arm	Measure	Value (MEAN)	Dispersion
iFuse Implant System	Improvement in Quality of Life (QOL) as Measured by EQ-5D (EuroQol-5D) at Post-operative Visits	0.31 units on a scale	Standard Deviation 0.22
Non-Surgical Management	Improvement in Quality of Life (QOL) as Measured by EQ-5D (EuroQol-5D) at Post-operative Visits	NA units on a scale	—

Secondary

Improvement in Quality of Life (QOL) as Measured by EQ-5D (EuroQol-5D) at Post-operative Visits

Time frame: 6 months

Population: Results show improvement in score from baseline.

Arm	Measure	Value (MEAN)	Dispersion
iFuse Implant System	Improvement in Quality of Life (QOL) as Measured by EQ-5D (EuroQol-5D) at Post-operative Visits	0.29 units on a scale	Standard Deviation 0.22
Non-Surgical Management	Improvement in Quality of Life (QOL) as Measured by EQ-5D (EuroQol-5D) at Post-operative Visits	0.06 units on a scale	Standard Deviation 0.28

Secondary

Improvement in Quality of Life (QOL) as Measured by EQ-5D (EuroQol-5D) at Post-operative Visits

Time frame: 24 months

Population: 13 iFuse subjects did not complete the 24-month assessment. Analysis was not done for the NSM group at 24 months due to the high crossover rate.

Arm	Measure	Value (MEAN)	Dispersion
iFuse Implant System	Improvement in Quality of Life (QOL) as Measured by EQ-5D (EuroQol-5D) at Post-operative Visits	0.29 units on a scale	Standard Deviation 0.24
Non-Surgical Management	Improvement in Quality of Life (QOL) as Measured by EQ-5D (EuroQol-5D) at Post-operative Visits	NA units on a scale	—

Secondary

Improvement in Quality of Life (QOL) as Measured by SF-36 PCS (Physical Component) at Post-operative Visits

Improvement in quality of life (QOL) as measured by SF-36 PCS (Physical Component) at post-operative / NSM visits. The Short Form 36 health survey (SF-36) is a 36-item patient reported health questionnaire to measure quality of life across 8 domains. The PCS is the Physical Component Summary score. PCS is normed, so that normal scores are 50 +- 10. Higher scores indicate higher quality of life; lower scores indicate lower quality of life. SF-36 PCS (NBS, 2009 norms) ranges from 5 (minimum value, poor physical function) to 80 (maximum, excellent clinical function). Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.

Time frame: 12 Months

Population: A total of 2 iFuse subjects had exited the study before making it to their 12 month visit. This outcome is not evaluated in the NSM group at month 12 because high crossover to surgical treatment prevents valid analysis.

Arm	Measure	Value (MEAN)	Dispersion
iFuse Implant System	Improvement in Quality of Life (QOL) as Measured by SF-36 PCS (Physical Component) at Post-operative Visits	13.0 units on a scale	Standard Deviation 9.9
Non-Surgical Management	Improvement in Quality of Life (QOL) as Measured by SF-36 PCS (Physical Component) at Post-operative Visits	NA units on a scale	—

Secondary

Improvement in Quality of Life (QOL) as Measured by SF-36 PCS (Physical Component) at Post-operative Visits

Time frame: 6 months

Population: 2 iFuse and 2 NSM subjects did not complete SF-36 at month 6.

Arm	Measure	Value (MEAN)	Dispersion
iFuse Implant System	Improvement in Quality of Life (QOL) as Measured by SF-36 PCS (Physical Component) at Post-operative Visits	12.5 units on a scale	Standard Deviation 10.5
Non-Surgical Management	Improvement in Quality of Life (QOL) as Measured by SF-36 PCS (Physical Component) at Post-operative Visits	1.3 units on a scale	Standard Deviation 8.2

Secondary

Improvement in Quality of Life (QOL) as Measured by SF-36 PCS (Physical Component) at Post-operative Visits

Time frame: 24 months

Population: Change in QOL score at 24 months. 89 participants had QOL information at 24 months. Analysis of the NSM cohort is not done because high crossover to surgery prevents valid analysis.

Arm	Measure	Value (MEAN)	Dispersion
iFuse Implant System	Improvement in Quality of Life (QOL) as Measured by SF-36 PCS (Physical Component) at Post-operative Visits	11.2 units on a scale	Standard Deviation 10.7
Non-Surgical Management	Improvement in Quality of Life (QOL) as Measured by SF-36 PCS (Physical Component) at Post-operative Visits	NA units on a scale	—

Secondary

Improvement in SI Joint Pain VAS Score at 12 Months

Improvement in SI joint pain VAS score of greater than or equal to 20 points compared to baseline. The Visual Analog Scale (VAS) is a 100 mm line on which the subject indicates their level of pain. 0 = no pain. 100 = worst imaginable pain. Note that secondary endpoint analysis is based on available data only. Subjects in the NSM group who crossed over are considered failures for this endpoint by definition.

Time frame: 12 Months

Population: 2 iFuse subjects did not complete the 12-month pain score. Analysis of 12-month scores in the NSM group is not valid because of the high crossover rate.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
iFuse Implant System	Improvement in SI Joint Pain VAS Score at 12 Months	81 Participants
Non-Surgical Management	Improvement in SI Joint Pain VAS Score at 12 Months	NA Participants

Secondary

Improvement in SI Joint Pain VAS Score at 1 Month

Improvement in SI joint pain VAS score of greater than or equal to 20 points, at post-operative & NSM visit after 1 month. The Visual Analog Scale (VAS) is a 100 mm line on which the subject indicates their level of pain. 0 = no pain. 100 = worst imaginable pain. Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.

Time frame: 1 month

Population: 2 iFuse and 1 NSM subjects did not complete the pain score.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
iFuse Implant System	Improvement in SI Joint Pain VAS Score at 1 Month	84 Participants
Non-Surgical Management	Improvement in SI Joint Pain VAS Score at 1 Month	13 Participants

Secondary

Improvement in SI Joint Pain VAS Score at 24 Months

Time frame: 24 Months

Population: 12 iFuse subjects did not complete the 24-month pain score. Analysis of 24-month scores in the NSM group is not valid because of the high crossover rate.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
iFuse Implant System	Improvement in SI Joint Pain VAS Score at 24 Months	75 Participants
Non-Surgical Management	Improvement in SI Joint Pain VAS Score at 24 Months	NA Participants

Secondary

Improvement in Si Joint Pain VAS Score at 3 Months

Improvement in SI joint pain VAS score of greater than or equal to 20 points, at post-operative & NSM visits after 3 months. The Visual Analog Scale (VAS) is a 100 mm line on which the subject indicates their level of pain. 0 = no pain. 100 = worst imaginable pain. Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.

Time frame: 3 Months

Population: 2 iFuse and 3 NSM subjects did not complete the 3-month pain score.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
iFuse Implant System	Improvement in Si Joint Pain VAS Score at 3 Months	87 Participants
Non-Surgical Management	Improvement in Si Joint Pain VAS Score at 3 Months	17 Participants

Secondary

Improvement in SI Joint Pain VAS Score at 6 Months

Improvement in SI joint pain VAS score of greater than or equal to 20 points, at post-operative & NSM visits after 6 months. The Visual Analog Scale (VAS) is a 100 mm line on which the subject indicates their level of pain. 0 = no pain. 100 = worst imaginable pain. Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.

Time frame: 6 Months

Population: 1 iFuse and 3 NSM subjects did not complete the 6-month pain score.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
iFuse Implant System	Improvement in SI Joint Pain VAS Score at 6 Months	84 Participants
Non-Surgical Management	Improvement in SI Joint Pain VAS Score at 6 Months	12 Participants

Secondary

Number of Participants With Serious Adverse Events (SAEs)

Any event meeting ISO 14155 definition for serious adverse event at following time points: during procedure (if randomized to iFuse), hospital discharge (if iFuse, typically 1-2 days), and 1, 3, 6, 12, 18 and 24 months after randomization.

Time frame: Procedure, discharge, 1, 3, 6, 12, 18 and 24 months

Population: All treated study subjects.

Arm	Measure	Value (COUNT_OF_PARTICIPANTS)
iFuse Implant System	Number of Participants With Serious Adverse Events (SAEs)	38 Participants
Non-Surgical Management	Number of Participants With Serious Adverse Events (SAEs)	12 Participants

Secondary

Work Status

Non-working subjects (due to back pain or other reasons) who return to work Note that secondary endpoint analysis is based on available data only. No imputation of missing scores was prespecified in the protocol.

Time frame: 3 Months