Six-month outcomes from a randomized controlled trial of minimally invasive SI joint fusion with triangular titanium implants vs conservative management

Management of sacroiliac joint pain: current concepts

INTRODUCTION

Managing sacroiliac joint (SIJ) pain is challenging and unpredictable. There are no internationally accepted recommendations. In light of the lack of global consensus and guidelines and the ongoing advancements in management options, a widely accepted treatment algorithm remains absent. This systematic review updates and evaluates the existing evidence on strategies for managing SIJ pain.

METHODS

This study followed the guidelines defined in the 2020 PRISMA statement. All clinical studies concerning the clinical management of SIJ pain were considered. Web of Science, PubMed, and Embase were accessed in January 2025 without additional filters or temporal constraints. The risk of bias evaluation and statistical analysis followed the guidelines described in the Cochrane Handbook for Systematic Reviews of Interventions.

RESULTS

Fifteen randomised controlled trials, 13 clinical trials, and 10 retrospective studies were included. Data from 2666 patients (1429 women) were retrieved. The mean length of follow-up was 14.7 ± 15.2 months. The mean age was 54.0 ± 5.8 years, and the mean BMI was 28.5 ± 2.5 kg/m2. Non-surgical options primarily focus on physical therapy to relieve discomfort. Different medications aim to decrease inflammation and pain at the SIJ. Fluoroscopically guided SIJ injections allow for directly administering steroids or mesenchymal stem cells into the joint. Radiofrequency denervation is frequently used to address SIJ pain, while surgical fusion is usually reserved for cases where conservative treatment is ineffective.

CONCLUSION

Managing SIJ pain is challenging due to limited and inconsistent evidence. Treatment progresses from conservative options, physiotherapy, lifestyle changes, and non-steroidal anti-inflammatory drugs to more invasive approaches like injections, radiofrequency denervation, and, in severe cases, surgical management. Research limitations include small sample sizes, short follow-ups, and inconsistent methodologies. Future high-quality studies are needed to establish clear diagnostic and treatment guidelines, compare techniques, and explore new therapies like regenerative medicine.

Utility of minimally invasive percutaneous arthrodesis of the sacroiliac joint for the treatment of low back pain: systematic review of the literature

BACKGROUND

The surprising increase observed in recent years in the use of minimally invasive sacroiliac joint arthrodesis techniques as a treatment for low back pain justifies an objective review of this results.

PURPOSE

carry out a systematic review of the literature to evaluate the clinical results of patients with low back pain treated with percutaneous arthrodesis of the SIJ.

STUDY DESIGN

Systematic review.

METHODS

Systematic search of the medical literature. The words used in the Search were: "Hollow screw system", "percutaneous sacroiliac joint stabilization", "sacroiliac joint", "minimally invasive", "sacroiliac pain", "sacroiliac dysfunction". With logical connectors such as "and", "not" and "or".

DATABASES

Pubmed, Scopus, Embase, Ovid, EBSCO host and google scholar. The search extended from the beginning of the databases until September 2024. The "Rayyan" program was used to collect the information and facilitate the analysis process.

INCLUSION CRITERIA

Systematic review from the literature, clinical trials, observational studies and case series. They followed PRISMA principles.

RESULTS

661 articles were found, of which 108 articles were duplicates. The criteria (Inclusion/Exclusion) were applied to the 553 articles identified based on the independent reading of the summaries by each of the authors on the Rayyan platform and 434 articles were excluded. The 119 selected articles were completely reviewed to finally obtain 102 articles included in the review. Epidemiological data were extracted into an Excel table, methodological and related to clinical results and safety of procedures made. The Prisma checklist for systematic reviews was applied in each article. The epidemiological quality of the articles was evaluated based on the checklists STROBE and CONSORT. The results regarding clinical improvement were overwhelming. However, most of the studies were sponsored by industry and with a limited population and follow-up not always prolonged.

CONCLUSIONS

Although the clinical results regarding the effectiveness of SIJ fusion are forceful for their effectiveness, we recommend considering some aspects for their analysis and especially long-term studies.

Clinical outcome measures following lateral versus posterior sacroiliac joint fusion: Systematic review and meta-analysis

Introduction

Sacroiliac joint fusion (SIJF) is indicated in patients with chronic Sacroiliac joint (SIJ) pain or instability and is usually performed using minimally invasive techniques through lateral or posterior approach.

Research question

Our study aims to compare the lateral approach to the posterior one in SIJF through meta-analysis of other studies. The outcome of each approach is measured using the visual analog scale (VAS), Oswestry disability index (ODI), or both.

Materials and methods

The study was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Articles were extracted using Pubmed advance search till February 27th, 2023. Articles included were those limited to either lateral, posterior or both approaches. Articles written in a non-English language, case reports and smaller-than-three case series were excluded from the study. Risk of bias was assessed using the Newcastle-Ottawa and Jadad scales. Stata-17 software program was used for statistical analysis and creation of forest plots.

Results

Forty-eight articles were available for the quantitative analysis, which represents a total of 2562 subjects. The average duration of postoperative follow-up was 21 months (3-72 months) and 17 months (6-72 months) for the VAS and ODI outcomes, respectively. The average percentage of improvement in the VAS was 57% (22-80%) in the lateral approach versus 58% (29-94%) in the posterior approach (p = 0.986). The average percentage of improvement in the ODI was 42% (11-75%) in the lateral approach versus 31% (11-65%) in the posterior one (p = 0.272). A trend towards performing posterior approaches more frequently was noted in studies published after 2017.

Discussion and conclusion

Approach selection for SIJF depends mainly on patient's characteristics and surgeon's experience. Our study demonstrated no difference in VAS outcome between lateral and posterior approach. Lateral approach appeared to be superior in ODI outcome although not statistically significant. The main limitation of the study is the selection-bias as the majority of articles included were observational. Therefore, randomized procedural trials are needed to validate these findings.

Safety and performance of a novel synthetic biomimetic scaffold for iliac crest defect reconstruction during surgical treatment of pelvic girdle pain: a first-in-human trial

INTRODUCTION

Surgical treatment of pelvic girdle pain (PGP) involves arthrodesis of sacroiliac (SI) and pubic symphysis joints. Fusion of pubic symphysis involves the implantation of an autologous iliac crest tricortical graft harvested from the iliac crest. The objective was to assess the safety of a novel synthetic graft substitute (b.Bone) for iliac crest reconstruction and to evaluate the results of PGP surgical treatment.

SOURCES OF DATA

Consecutive participants undergoing pelvic fusion and requiring iliac crest reconstruction were enrolled and followed-up for 12 months in a prospective first-in-human clinical investigation. Adverse events were documented, and health-related quality of life was evaluated using EuroQol-5D-5L questionnaire. Iliac crest defect healing was evaluated by the Modified Lane and Sandhu radiological scoring system. In addition, relevant published peer-reviewed scientific articles identified from PubMed.

AREAS OF AGREEMENT

The EQ-5D-5L scores improved steadily reaching the highest point at 365 days. By 365 days complete healing of the bone defect was observed.

AREAS OF CONTROVERSY

The management of PGP remains challenging with mixed results reported in the literature.

GROWING POINTS

While there is lack of consensus on how to manage PGP, the present study shows improved outcomes at one year following surgery. The synthetic b.Bone scaffold is a safe option with good healing outcomes for iliac crest defect reconstruction.

AREAS TIMELY FOR DEVELOPING RESEARCH

Although b.Bone synthetic scaffold found to be safe, further studies reporting on surgical treatment of PGP are required to confirm the findings in comparative trials.

Catamaran SI Joint Fusion System(R) MAINSAILTM Study: a prospective, single-arm, multi-center, post-market study of six-month clinical outcomes and twelve-month radiographic findings

BACKGROUND

Minimally invasive surgical techniques for sacroiliac joint (SIJ) fixation have the potential to reduce risk and improve patient outcomes, but evidence remains limited. This interim analysis presents initial findings from an ongoing prospective study evaluating the safety and efficacy of the Catamaran System.

METHODS

The primary endpoint of success at 6 months was defined as a ≥20 mm improvement in SIJ pain (Visual Analog Scale, VAS), no neurologic worsening, absence of device-related serious adverse events (SAEs), and no surgical reintervention. Secondary endpoints included 6 month evaluation of the Oswestry Disability Index (ODI), patient satisfaction, and 12 month radiographic CT fusion, performed by an indpendent radiologist.

RESULTS

Thirty-three consecutive patients (mean age: 58.9 years; %-females: 76%; Body Mass Index: 30.5) were treated across six U.S. clinical sites. At the primary endpoint of 6 months, 80% of patients met the criteria for success, with no device-related SAEs and no surgical reintervention reported. VASSIJ-Pain significantly decreased from preoperative levels (mean: 80.9 mm) to 6 months postoperatively (31.1 mm; p < 0.001). Mean ODI scores also showed a significant improvement from preoperative values (51.9%) to 6 months postoperatively (29.6%, p < 0.01). Patients reported high satisfaction rates throughout all follow-ups, with 93.3% of patients being satisfied at 6 months.

CONCLUSION

In patients diagnosed with chronic SIJ pain, minimally invasive inferior-posterior delivery of the Catamaran implant was safe and effective in relieving pain and reducing disability.

Patient-reported outcomes after minimally invasive sacro-iliac joint surgery: a cohort study based on the Swedish Spine Registry

BACKGROUND AND PURPOSE

There is conflicting evidence regarding treatment outcomes after minimally invasive sacroiliac joint fusion for long-lasting severe sacroiliac joint pain. The primary aim of our cohort study was to investigate change in patient-reported outcome measures (PROMs) after minimally invasive sacroiliac joint surgery in daily practice in the Swedish Spine Registry. Secondary aims were to explore the proportion of patients reaching a patient acceptable symptom score (PASS) and the minimal clinically important difference (MCID) for pain scores, physical function, and health-related quality of life outcomes; furthermore, to evaluate self-reported satisfaction, walking distance, and changes in proportions of patients on full sick leave/disability leave and report complications and reoperations.

METHODS

Data from the Swedish Spine Registry was collected for patients with first-time sacroiliac joint fusion, aged 21 to 70 years, with PROMs available preoperatively, at 1 or 2 years after last surgery. PROMs included Oswestry Disability Index (ODI), Numeric Rating Scale (NRS) for low back pain (LBP) and leg pain, and EQ-VAS, in addition to demographic variables. We calculated mean change from pre- to postoperative and the proportion of patients achieving MCID and PASS.

RESULTS

68 patients had available pre- and postoperative data, with a mean age of 45 years (range 25-70) and 59 (87%) were female. At follow-up the mean reduction was 2.3 NRS points (95% confidence interval [CI] 1.6-2.9; P < 0.001) for LBP and 14.8 points (CI 10.6-18.9; P < 0.001) for ODI. EQ-VAS improved by 22 points (CI 15.4-30.3, P < 0.001) at follow-up. Approximately half of the patients achieved MCID and PASS for pain (MCID NRS LBP: 38/65 [59%] and PASS NRS LBP: 32/66 [49%]) and physical function (MCID ODI: 27/67 [40%] and PASS ODI: 24/67 [36%]). The odds for increasing the patient's walking distance to over 1 km at follow-up were 3.5 (CI 1.8-7.0; P < 0.0001), and of getting off full sick leave or full disability leave was 0.57 (CI 0.4-0.8; P = 0.001). In the first 3 months after surgery 3 complications were reported, and in the follow-up period 2 reoperations.

CONCLUSION

We found moderate treatment outcomes after minimally invasive sacroiliac joint fusion when applied in daily practice with moderate pain relief and small improvements in physical function.

Safety, Efficacy, and Durability of Outcomes: Results from SECURE: A Single Arm, Multicenter, Prospective, Clinical Study on a Minimally Invasive Posterior Sacroiliac Fusion Allograft Implant

Introduction

Research suggests that sacroiliac joint (SIJ) dysfunction is responsible for 15% to 30% of reported low back pain cases. Recently, there has been an increasing interest in SIJ fusion using minimally invasive surgery (MIS) due to safety. Initially, devices designed for MIS were intended for lateral approaches. A minimally invasive sacroiliac fusion implant for use with a posterior approach has been developed and is regulated for clinical use under the regulatory framework required for human cells, tissues, or cellular or tissue-based products (HCT/Ps).

Methods

A multi-center, prospective, single-arm study was launched after initial studies provided preliminary data to support safety, efficacy, and durability of this minimally invasive sacroiliac posterior fusion LinQ allograft implant (NCT04423120). Preliminary results were reported previously. Final results for the full participant cohort are presented here.

Results

One-hundred and fifty-nine (159) participants were enrolled across 16 investigational sites in the US between January 2020 and March 2022. One-hundred and twenty-two (122) participants were implanted. At the 1-month follow-up, 82 participants satisfied all criteria for the composite responder endpoint, representing 73.2% of the study cohort. These results stayed consistent across the remaining study timepoints with 66.0%, 74.4%, and 73.5% of participants classified as responders at the 3-, 6- and 12-month follow-up visits, respectively. VAS scores were significantly reduced (p < 0.0001) and ODI scores were significantly improved (p < 0.0001). All domains of the PROMIS-29 were also significantly improved (all p's <0.0001). Only one procedure-related serious AE was reported in the study.

Conclusion

These results suggest that the posterior approach LinQ Implant System is a safe and effective treatment for sacroiliac joint dysfunction at 12 months, with results that are favorable compared to outcomes reported for an FDA-cleared lateral approach.

Effect of sacroiliac fusion on gait, standing balance, and pelvic mobility for unilateral sacroiliac joint dysfunction

Background

Sacroiliac joint fusion (SIF) has been shown to effectively alleviate pain and improve functional deficits associated with sacroiliac joint dysfunction (SIJD). Previous studies have demonstrated significant improvements in gait function, however, none have reported both over-ground walking and quiescent standing, and additionally, none have included analysis of pelvic kinematics which may contain important information regarding pain avoidant compensatory behaviors. The purpose of this study was to identify objective functional differences between symptomatic and asymptomatic sides of unilateral sacroiliac joint dysfunction (SIJD) patients and to demonstrate the effectiveness of unilateral sacroiliac fusion (SIF) to improve gait and balance function compared to matched controls.

Methods

Thirteen unilateral SIJD patients were evaluated before and 6 months after SIF and were compared to matched asymptomatic controls. Pain and disability were assessed using visual analog scales and the Oswestry disability index respectively. Over ground walking and standing balance were assessed using 3D joint kinematics and kinetic ground reaction force analyses.

Results

Preoperatively, SIJD patients reported high levels of pain and disability and exhibited significant deficits in gait including elevated step width, reduced hip flexion/extension, and elevated pelvic motion as well as elevated center of pressure sway characteristics during standing. After unilateral SIF, patients reported significant reductions in pain and demonstrated significant improvements in gait including normalization of step width between sides and improved hip motion however elevated pelvic obliquity and rotation motion remained. Improvements in standing balance included reduced coronal sway characteristics and normalization of loading symmetry between sides.

Conclusion

Unilateral SIF resulted in significant improvements in both gait and balance function among SIJD patients to levels comparable to matched controls, however elevated pelvic motion remained. These findings help inform surgeons on the effectiveness of SIF for unilateral SIJD and provide important information regarding interpretation of functional outcomes.

The American Society of Pain and Neuroscience (ASPN) Evidence-Based Clinical Guideline of Interventional Treatments for Low Back Pain

Introduction

Painful lumbar spinal disorders represent a leading cause of disability in the US and worldwide. Interventional treatments for lumbar disorders are an effective treatment for the pain and disability from low back pain. Although many established and emerging interventional procedures are currently available, there exists a need for a defined guideline for their appropriateness, effectiveness, and safety.

Objective

The ASPN Back Guideline was developed to provide clinicians the most comprehensive review of interventional treatments for lower back disorders. Clinicians should utilize the ASPN Back Guideline to evaluate the quality of the literature, safety, and efficacy of interventional treatments for lower back disorders.

Methods

The American Society of Pain and Neuroscience (ASPN) identified an educational need for a comprehensive clinical guideline to provide evidence-based recommendations. Experts from the fields of Anesthesiology, Physiatry, Neurology, Neurosurgery, Radiology, and Pain Psychology developed the ASPN Back Guideline. The world literature in English was searched using Medline, EMBASE, Cochrane CENTRAL, BioMed Central, Web of Science, Google Scholar, PubMed, Current Contents Connect, Scopus, and meeting abstracts to identify and compile the evidence (per section) for back-related pain. Search words were selected based upon the section represented. Identified peer-reviewed literature was critiqued using United States Preventive Services Task Force (USPSTF) criteria and consensus points are presented.

Results

After a comprehensive review and analysis of the available evidence, the ASPN Back Guideline group was able to rate the literature and provide therapy grades to each of the most commonly available interventional treatments for low back pain.

Conclusion

The ASPN Back Guideline represents the first comprehensive analysis and grading of the existing and emerging interventional treatments available for low back pain. This will be a living document which will be periodically updated to the current standard of care based on the available evidence within peer-reviewed literature.

The efficacy of primary sacroiliac joint fusion for low back pain caused by sacroiliac joint pathology: a systematic review and meta-analysis

PURPOSE

Conduct a systematic review to quantify the effect of primary sacroiliac joint fusion (SIJF) for the treatment of sacroiliac (SI) joint pathology on patient reported outcomes.

METHODS

Medline, Embase, Cochrane, PubMed, and Scopus databases were searched prior to August 18th, 2020 for all English-Language studies involving the treatment of SIJ pathology through SIJF and/or conservative management (CM). The quality of included studies was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE). Primary outcome measure was the Visual Analogue Scale (VAS) for low back pain. Secondary outcome measure was the Oswestry Disability Index (ODI) and the incidence of adverse reactions.

RESULTS

A total of 564 patients and six studies were included. The overall quality of evidence analyzed by this review was low (GRADE = 0). Five out of the six studies were industry funded. The VAS standardized mean difference (SMD) between SIJF and CM at three months and six months follow-up was - 1.4 [95% confidence interval - 2.3, - 0.6] and - 1.5 [95% CI - 1.8, - 1.1]. The ODI SMD between SIJF and CM scores at three months and 6 months follow-up was - 0.9 [95% CI - 1.1, - 0.7] and - 1.1 [95% CI - 1.6, - 0.5]. The odds ratio of adverse reactions due to SIJF compared to CM was 1.9 [95% CI 0.1, 42.8].

CONCLUSION

Based on the limited number of independent trials with long-term follow-up, SIJF shows potential as a surgical treatment option for SIJ pathology.

PROSPERO REGISTRATION

CRD42020206149 (25th September 2020).

Relationship Between Sacroiliac Joint-related Pain and Spinopelvic Mobility

STUDY DESIGN

A case-control study.

OBJECTIVE

To evaluate the relationship between sacroiliac joint-related pain (SIJ-RP) and spinopelvic mobility.

SUMMARY OF BACKGROUND DATA

No specific radiological findings are available for the diagnosis of SIJ-RP. A previous study reported that a higher pelvic incidence and sacral slope (SS) values were significantly associated with sacroiliac joint pain. The concept of spinopelvic mobility, which is evaluated by the differences between SS in the standing and sitting positions, has been the focus of hip and spine surgeries in recent years.

MATERIALS AND METHODS

The SIJ-RP group comprised patients diagnosed with SIJ-RP based on physical findings and their response to analgesic injections. No other lumbar or hip joint diseases were observed. The non-SIJ-RP group comprised patients with lower back pain for reasons other than SIJ-RP. Radiographs of the lateral view of the pelvis in the standing and sitting positions were evaluated for all patients. We compared and analyzed the backgrounds, SS in the two positions, and difference in SS between the two positions in both groups.

RESULTS

In total, 245 patients were included in the study, with 49 and 196 patients in the SIJ-RP and non-SIJ-RP groups, respectively. More female patients experienced SIJ-RP than male patients ( P =0.0361). There were significant differences between the groups for SS in standing ( P =0.0076), sitting ( P =0.0005), and those with a difference between sitting and standing of <5° ( P =0.0278) in the univariate analyses. Logistic regression analyses, after adjustment for age and sex, revealed significant differences between the groups with an SS difference <5° ( P =0.0088; 95% confidence interval, 1.280-5.519), with an odds ratio of 2.7.

CONCLUSION

On evaluating spinopelvic mobility, we found that SIJ-RP was related to hypomobility of the sacrum, which could indicate the hypermobility of the sacroiliac joint.

Cost-Utility Analysis of Sacroiliac Joint Fusion in High-Risk Patients Undergoing Multi-Level Lumbar Fusion to the Sacrum

Purpose

Multi-level lumbar fusion to the sacrum (MLF) can lead to increased stress and angular motion across the sacroiliac joint (SIJ), with an incidence of post-operative SIJ pain estimated at 26–32%. SIJ fusion (SIJF) can help obviate the need for revisions by reducing range of motion and screw stresses. We aimed to evaluate the cost-utility of MLF + SIJF compared to MLF alone among high-risk patients from a payer perspective, where high risk is defined as high body mass index and high pelvic incidence.

Methods

A Markov process decision-analysis model was developed to evaluate cumulative 5-year costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER) of MLF + SIJF compared to MLF alone using published data; costs from Medicare claims data analyses and health state utility values (derived from EQ-5D) informed by three prospective, multicenter, clinical trials. The base case assumed a reduction in post-operative SIJ pain from 30% to 10% (relative risk reduction [RRR] of 67%). Costs and utilities were discounted 3% annually. The ICER is reported in 2020 US dollars. One-way, multi-way, and probabilistic sensitivity analyses were performed.

Results

With an assumed 30% incidence of SIJ pain after MLF alone, stabilizing with SIJF was associated with an additional 5-year cost of $2421 and a gain of 0.14 QALYs, resulting in an ICER of $17,293 per QALY gained (similar to total knee arthroplasty and more favorable than open discectomy). ICERs were most sensitive to the RRR of post-operative SIJ pain conferred by SIJF, time horizon, and probability of successful treatment with MLF alone. At a willingness-to-pay threshold of $50,000/QALY gained, MLF + SIJF has a 97.7% probability of being cost-effective in the target patient population.

Conclusion

Fusing the SIJ in high-risk patients undergoing MLF was cost-effective when the incidence of post-operative SIJ pain after MLF alone exceeds approximately 25%, providing value-based healthcare from a payer perspective.

Minimally invasive sacroiliac joint fusion for chronic sacroiliac joint pain: a systematic review

BACKGROUND CONTEXT

Sacroiliac (SI) joint pain causes significant disability and impairment to quality of life (QOL). Minimally invasive SI joint fusion is increasingly used to relieve chronic SI joint pain among patients who do not respond to nonsurgical treatment.

PURPOSE

To systematically review the existing literature to assess the effectiveness and safety of minimally invasive SI joint fusion.

STUDY DESIGN/SETTING

Systematic review.

DATA SOURCES

PubMed, Embase, Cochrane, and a clinical trial registry from database inception to June 30, 2021.

STUDY SELECTION

Eligible studies were primary research studies published in the English language, enrolled adults with SI joint pain, and compared SI joint fusion to nonsurgical interventions or alternative minimally invasive procedures. We included randomized controlled trials (RCTs) or controlled cohort studies (CCSs) that reported effectiveness (pain, physical function, QOL, opioid use) or safety outcomes (adverse events [AEs], revision surgeries) and uncontrolled studies that reported safety outcomes.

DATA ABSTRACTION AND SYNTHESIS

Data were abstracted into structured forms; two independent reviewers assessed risk of bias using standard instruments; certainty of evidence was rated using GRADE.

RESULTS

Forty studies (2 RCTs, 3 CCSs, and 35 uncontrolled studies) were included. Minimally invasive SI joint fusion with the iFuse Implant System appeared to result in larger improvements in pain (two RCTs: mean difference in visual analog scale -40.5 mm, 95% CI, -50.1 to -30.9; -38.1 mm, p<.0001) and larger improvements in physical function (mean difference in Oswestry Disability Index -25.4 points, 95% CI, -32.5 to -18.3; -19.8 points, p<.0001) compared to conservative management at 6 months. Improvements in pain and physical function for the RCTs appeared durable at 1- and 2-year follow-up. Findings were similar in one CCS. The two RCTs also found significant improvements in QOL at 6 months and 1 year. Opioid use may be improved at 6 months and 1 to 2 years. AEs appeared higher in the fusion group at 6 months. The incidence of revision surgery varied by study; the highest was 3.8% at 2 years. Two CCSs compared the effectiveness of alternative minimally invasive fusion procedures. One CCS compared iFuse to the Rialto SI Fusion System and reported no differences in pain, function, QOL, and revision surgeries from 6 months to 1 year. One CCS compared iFuse to percutaneous screw fixation and reported significantly fewer revisions among iFuse participants (mean difference -61.0%, 95% CI, -78.4% to -43.5%). The 35 uncontrolled studies had serious limitations and reported heterogeneous safety outcomes. Two of the larger studies reported a 13.2% incidence of complications from minimally invasive SI joint fusion at 90 days using an insurance claims database and a 3.1% incidence of revision surgery over 2.5 years using a postmarket surveillance database.

CONCLUSIONS

Among patients meeting diagnostic criteria for SI joint pain and who have not responded to conservative care, minimally invasive SI joint fusion is probably more effective than conservative management for reducing pain and opioid use and improving physical function and QOL. Fusion with iFuse and Rialto appear to have similar effectiveness. AEs appear to be higher for minimally invasive SI joint fusion than conservative management through 6 months. Based on evidence from uncontrolled studies, serious AEs from minimally invasive SI joint fusion may be higher in usual practice compared to what is reported in trials. The incidence of revision surgery is likely no higher than 3.8% at 2 years. Limited evidence is available that compares different minimally invasive devices.

Six Month Interim Outcomes from SECURE: A Single arm, Multicenter, Prospective, Clinical Study on a Novel Minimally Invasive Posterior Sacroiliac Fusion Device

INTRODUCTION

Sacroiliac joint disease is a prominent diagnosis across the world. A novel fixation technique employing a posterior approach, single point, bone allograft tranfixation has proven to be helpful anecdotally. The purpose of this is study is to investigate prospectively the safety and efficacy of this approach.

METHODS

A multicenter, prospective, single arm study was performed after patient identification and treatment with the novel posterior fusion, single-point transfixation system and followed for 24 months. Target enrollment is 100 patients. Interim results on the first 69 consecutive patients at 6 months is presented. Primary endpoint at 6-month analysis was Pain Intensity reduction by visual analogue scale and functional improvement by Oswestry Disability Index. Adverse events were assessed for safety analysis.

RESULTS

: 69 patients were identified for this analysis. At 6 months, a mean improvement of 34.9 was identified by a reduction in VAS and functional improvement was demonstrated by a mean reduction in ODI of 17.7. There were three adverse events, all unrelated to the device.

CONCLUSION

The posterior single point transfixation is safe and efficacious for the treatment of sacroiliac joint dysfunction with statistical improvements in pain and function.

Beyond the pedicle screw-a patent review

PURPOSE

This review provides an overview of the patent literature on posteriorly placed intrapedicular bone anchors. Conventional pedicle screws are the gold standard to create a fixation in the vertebra for spinal fusion surgery but may lack fixation strength, especially in osteoporotic bone. The ageing population demands new bone anchors that have an increased fixation strength, that can be placed safely, and, if necessary, can be removed without damaging the surrounding tissue.

METHODS

The patent search was conducted using a classification search in the Espacenet patent database. Only patents with a Cooperative Patent Classification of A61B17/70 or A61B17/7001 concerning spinal positioners and stabilizers were eligible for inclusion. The search query resulted in the identification of 731 patents. Based on preset inclusion criteria, a total of 56 unique patents on different anchoring methods were included, reviewed and categorized in this study.

RESULTS

Five unique fixation methods were identified; (1) anchors that use threading, (2) anchors that utilize a curved path through the vertebra, (3) anchors that (partly) expand, (4) anchors that use cement and (5) anchors that are designed to initiate bone ingrowth. Of the anchor designs included in this study, eight had a corresponding commercial product, six of which were evaluated in clinical trials.

CONCLUSION

This review provides insights into worldwide patented intrapedicular bone anchors that aim to increase the fixation strength compared to the conventional pedicle screw. The identified anchoring methods and their working principles can be used for clinical decision-making and as a source of inspiration when designing novel bone anchors.

Impact of diagnosis and type of sacroiliac joint fusion on postoperative complications

PURPOSE

Two main surgical approaches are available for fusing the sacroiliac joint (SIJ): an open or minimally invasive (MIS) approach. The purpose of this study was to analyze the associated total hospital charges and postoperative complications of the MIS and open approach.

METHODS

Using the 2016 and 2017 National Readmission Database, we conducted a retrospective cohort analysis of 2521 patients who received a SIJ fusion with an open (N = 1990) or MIS (N = 531) approach for diagnosed sacrum pain, sacroiliitis, sacral instability, or spondylosis. Each cohort was analyzed for postoperative complications.

RESULTS

We identified 604 patients diagnosed with sacrum pain, 1142 with sacroiliitis, 315 with spondylosis, and 288 with sacral instability. Patients who received the open approach for sacrum pain had significantly higher rates of novel post-procedural pain (p = 0.045) and novel lumbar pathology (p = 0.015) within 30 days. On 30-day follow-up, patients with sacroiliitis treated with open SIJ fusion had significantly higher rates of novel postprocedural pain compared to those treated with MIS fusion (p = 0.045). Patients who received the open approach for spondylosis resulted in significantly higher rates of non-elective readmission within 30 days compared to the MIS approach (p < 0.0001). In addition, the open technique for spondylosis resulted in significantly higher rates of non-elective readmissions for infection within 30 days (p = 0.014). On 30-day follow-up, patients with sacral instability treated with open SIJ fusion had significantly higher rates of UTI (p = 0.045).

CONCLUSION

Our study suggests that there exist unique postoperative complications that arise after SIJ fusion specific to preoperative diagnosis and surgical approach.

Propensity-matched Analysis of 1062 Patients Following Minimally Invasive Versus Open Sacroiliac Joint Fusion

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

The aim of this study was to compare the hospital charges and postoperative complications of minimally invasive surgery (MIS) and open approaches to sacroiliac joint (SIJ) fusion.

SUMMARY OF BACKGROUND DATA

The data source utilized in this study is the Healthcare Cost and Utilization Project National Readmission Database (NRD) from 2016 and 2017. The NRD is a yearly nationally representative inpatient database from the Agency for Healthcare Research and Quality with information regarding patient demographics, diagnoses, procedures, and readmissions.

MATERIALS AND METHODS

The 2016-2017 NRD was used to identify 2521 patients receiving SIJ fusion with open (n=1990) or MIS approaches (n=531) for diagnosed sacrum pain, sacroiliitis, sacral instability, or spondylosis after excluding for those who received prior SIJ fusion, those diagnosed with neoplasms or trauma of the pelvis or sacrum, and nonelective procedures. We then one-to-one propensity-matched the open (n=531) to the MIS approach (n=531) for age, sex, and Charlson Comorbidity Index. Statistical analysis was performed to compare total hospital charges, immediate surgical complications, nonelective readmission rate, and 30-, 90-, and 180-day postoperative complications between the 2 approaches.

RESULTS

The mean total hospital charge was the only significant difference between 2 group. Open SIJ fusion had significantly higher charge compared with the MIS approach (open $101,061.90±$81,136.67; MIS $83,594.78±$49,086.00, P<0.0001). The open approach was associated with nonsignificant higher rates of novel lumbar pathology at 30-, 90-, and 180-day readmissions and revision surgeries at 30 and 180 days. MIS approach had higher rates nervous system complications at 30-, 90-, and 180-day readmission, as well as infection and urinary tract infection within 30 days, none being significant. Novel postprocedural pain was similar between the 2 groups at 90 and 180 days.

CONCLUSIONS

The current study found that open SIJ fusion was associated with significantly higher hospital charges. Although no significant differences in postoperative complications were found, there were several notable trends specific to each surgical approach.

CT Scan and Clinical Outcomes of Novel Lateral-Oblique Percutaneous Sacroiliac Joint (SIJ) Fixation: Technique and Literature Review

Purpose The sacroiliac joint (SIJ) is estimated to be a source of pain in 15%-30% of patients presenting for the evaluation of low back pain. The SIJ may develop symptoms in an estimated 43% of patients who have had previous lumbar fusion surgeries. With increased awareness of SIJ as a pain source and for those patients who have intractable pain and who fail nonoperative treatment, surgery to stabilize the SIJ is becoming more common. Thus multiple different technologies and techniques need to be evaluated. The purpose of this study is to report on the clinical and radiographic follow-up of percutaneous lateral-oblique sacroiliac joint fusion with a threaded compression screw performed in an outpatient ambulatory surgery center (ASC). Methods Three consecutive patients were chosen for this technique, and after completion, were followed for at least 24 months as part of a pilot study to see how they responded to the treatment. The medical charts of these patients were reviewed along with follow-up radiographs and computed tomography (CT) scans to assess for radiographic fusion designated as bridging bone across the SIJ with no signs of implant loosening such as haloes around the screws, change in position, or screw breakage. The SacroFuse (Sacrix LLC, Boston, MA) SIJ screws were 12 mm x 60 mm at S1 and 12 mm x 50 mm at S2 with threads for compressive fixation and cannulated for percutaneous placement over a guidewire. We evaluated patients' demographics, the pain visual analog scale (VAS) score, and the Oswestry Disability Index (ODI) preoperatively and postoperatively. Results Our first patient was a 51-year-old male body mass index (BMI) 33.3 kg/m² with a previous lumbar fusion. He underwent a two-staged SIJ fusion. The first surgery was done as an open direct lateral surgery, and the second stage was performed three months later using a direct percutaneous lateral-oblique technique for three months. The second and third patients, respectively, were 22-year-old female status prior L5-S1 anterior lumbar interbody fusion (ALIF) plus right posterior unilateral pedicle screws. She had a BMI of 38.3 kg/m². The third patient was a 41-year-old male with a BMI of 29.5 kg/m² who underwent lateral-oblique bilateral percutaneous SIJ fixation. The latest CT imaging of each patient demonstrated increased bone density adjacent and within implants with intra-articular osseous bridging. There were no implant failures or complications. Conclusion This pilot study demonstrated the feasibility and effectiveness of a new percutaneous lateral-oblique SIJ fusion technique with a threaded compression screw done safely in an ASC. Patients demonstrated early pain relief and long-term fusion of their SIJ. We introduced the Sacrix line as a key fluoroscopic landmark for the success of this percutaneous technique.

Trends in Diagnosis and Treatment of Sacroiliac Joint Pathology Over the Past 10 Years: Review of Scientific Evidence for New Devices for Sacroiliac Joint Fusion

Sacroiliac (SI) joint pathology is a newly appreciated contributor to lower back pain. Sacroiliac joint fusion (SIJF) has grown rapidly in popularity in association with the advent of minimally-invasive surgical techniques. This has led to an explosion of new medical devices used for SIJF. The objective of this article is to outline clinical trends, summarize the current data, and categorize novel devices for SIJF. Trends in SI joint pathology and fusion were obtained via the Healthcare Cost and Utilization Project’s (HCUP) National Inpatient Sample (NIS) database and Web of Science. To review literature on devices for SIJF, PubMed was searched using the Boolean phrase “sacroiliac joint AND (fusion OR arthrodesis)” since 2010. To establish a list of SIJF devices not represented in the literature, searches were performed on the FDA 510(k), premarket approval, and de novo databases, as well as Google and LinkedIn. Literature review yielded 11 FDA-approved devices for minimally invasive SIJF. Database query yielded an additional 22 devices for a total of 33 devices. Twenty-one devices used the lateral transiliac approach, six posterior allograft approach, three posterolateral approach, and three combined the lateral transiliac and posterolateral approaches. The evidence for the lateral transiliac approach is the most robust. Many novel devices have been developed for minimally invasive SIJF over the past 10 years. Further randomized comparative trials are warranted to evaluate different surgical approaches and novel devices at this time.

Minimally Invasive Sacroiliac Joint Fusion with Triangular Titanium Implants: Cost-Utility Analysis from NHS Perspective

OBJECTIVE

The aim was to identify the cost-effectiveness of minimally invasive sacroiliac joint fusion (MI SIJF) surgery with titanium triangular implants for patients with sacroiliac joint (SIJ) pain who have failed conservative management, compared to non-surgical management (NSM) from a National Health Service (NHS) England perspective.

METHODS

Over a time horizon of 5 years, a cohort state transition model compared the costs and outcomes of treating patients with MI SIJF to those of traditional NSM treatment pathways. The NSM arm included two treatments: grouped physical therapy and corticosteroid injections (PTSI) or radiofrequency ablation (RFA). Three different strategies were considered: (1) a stepped pathway, (2) patients split between PTSI and RFA, and (3) RFA only. The outcome measure was incremental cost-effectiveness ratio (ICER), reported in 2018 British pounds per quality-adjusted life year (QALY) gained. One-way and probabilistic sensitivity analyses were used to test the robustness of the model results.

RESULTS

Patients undergoing MI SIJF accrued total procedure-related and pain-management costs of £8358, while NSM treatment strategy 1 had total costs of £6880. The MI SIJF cohort had 2.98 QALYs compared to strategy 1 with 2.30 QALYs. This resulted in an ICER for MI SIJF versus strategy 1 of £2164/QALY gained. Strategy 2 of the NSM arm had lower costs than strategy 1 (£6564) and 2.26 QALYs, and this resulted in an ICER of £2468/QALY gained for MI SIJF. Strategy 3 of the NSM arm had lower costs than strategy 1 (£6580), and this resulted in 2.28 QALYs and an ICER of £2518/QALY gained for MI SIJF. Probabilistic sensitivity analysis shows that at a threshold of £20,000/QALY gained, MI SIJF has a probability of being cost-effective versus NSM strategies of 96%, 97%, and 91% for strategies 1, 2, and 3, respectively.

CONCLUSION

MI SIJF appears to be cost-effective over a 5-year time horizon when compared to traditional NSM pathways in an NHS context.

Review of Current Evidence for Minimally Invasive Posterior Sacroiliac Joint Fusion

The sacroiliac joint (SIJ) is a large, irregularly shaped, serpentine joint structure bordered anteriorly and posteriorly by the sacroiliac ligaments. With increased recognition of the SIJ as a pain source, treatments have been historically nonsurgical in nature. Common treatments include bracing, medications, activity modification, manual therapy, chiropractic manipulation, physical therapy, and intra-articular SIJ injections. Surgical stabilization and/or fusion of the SIJ may be considered when a patient has persistent moderate to severe pain, functional impairment, and failed conservative management. Surgical stabilization and fusion has traditionally been by way of the transiliac approach. More recent SIJ fusion systems have proposed not only a posterior approach but one that stabilizes the joint space by placing an allograft within the SIJ. Anatomically, a posterior approach is able to avoid neurovascular structures that otherwise are encountered with the transiliac approach and may be performed percutaneously. Preliminary evidence reports consistent pain reduction with minimal complications. This paper is purposed to detail the present evidence of minimally invasive posterior SIJ fusion, as well as highlight the need for further research moving forward.

In-vitro 3D Analysis of Sacroiliac Joint Kinematics: Primary and Coupled Motions

STUDY DESIGN

An in-vitro biomechanical study of human cadaver sacroiliac joints.

OBJECTIVE

Our study aimed to develop a more comprehensive understanding of the native motion of the SIJ within the context of spinal kinematics and spinal implant evaluation.

SUMMARY OF BACKGROUND DATA

Increasing attention has been given to the sacroiliac joint (SIJ) as a source of low back pain, despite its limited range of motion. We sought to characterize the rotational and translational motion in each axis utilizing standard pure moment flexion-extension (FE), lateral bending (LB), and axial rotation (AR) testing.

METHODS

Sixteen sacroiliac joints were evaluated from eight lumbosacral cadaver specimens (six females, two males) from subjects aged 28 to 57 years (mean age 46.8) with body mass index (BMI) 22 to 36 (mean BMI 30). Single leg stance was modeled by clamping the blocks on one ischium in a vise and letting the contralateral ischium hang freely. Pure moment loading was applied in FE, right/left AR, and right/left LB. Relative motions were collected with infrared markers.

RESULTS

The on-axis ratio was significantly lower in LB than in FE (P = 0.012) and in AR (P = 0.017). The rotation deviation angle measured 13.9 ± 9.1° in FE, 17.1 ± 8.7° in AR, and 35.7 ± 25.7° in LB. In LB the rotational deviation angle is significantly higher than both FE and AR (P = 0.003 and P = 0.011, respectively). In-plane translation was significantly higher (P = 0.005) in FE loading than in LB loading.

CONCLUSION

A nontrivial amount of rotation and translation occurred out of the expected axis of motion. The largest amount of off-axis rotation was observed in lateral bending. Relative to resultant translation, in-plane translation was lowest in lateral bending. Our results indicate that rotation of the SIJ is not fully described with the in-plane metrics which are normally reported in evaluation of fusion devices. Future studies of the SIJ may need to consider including off-axis rotation measurements when describing SIJ kinematics.Level of Evidence: 5.

Invasive Treatments for Low Back Disorders

OBJECTIVE

This abbreviated version of the American College of Occupational and Environmental Medicine's Low Back Disorders guideline reviews the evidence and recommendations developed for invasive treatments used to manage low back disorders.

METHODS

Comprehensive systematic literature reviews were accomplished with article abstraction, critiquing, grading, evidence table compilation, and guideline finalization by a multidisciplinary expert panel and extensive peer-review to develop evidence-based guidance. Consensus recommendations were formulated when evidence was lacking and often relied on analogy to other disorders for which evidence exists. A total of 47 high-quality and 321 moderate-quality trials were identified for invasive management of low back disorders.

RESULTS

Guidance has been developed for the invasive management of acute, subacute, and chronic low back disorders and rehabilitation. This includes 49 specific recommendations.

CONCLUSION

Quality evidence should guide invasive treatment for all phases of managing low back disorders.

International Society for the Advancement of Spine Surgery Policy 2020 Update-Minimally Invasive Surgical Sacroiliac Joint Fusion (for Chronic Sacroiliac Joint Pain): Coverage Indications, Limitations, and Medical Necessity

The index 2014 International Society for the Advancement of Spine Surgery Policy Statement-Minimally Invasive Surgical Sacroiliac Joint Fusion-was generated out of necessity to provide an International Classification of Diseases, Ninth Revision (ICD-9)-based background and emphasize tools to ensure correct diagnosis. A timely ICD-10-based 2016 update provided a granular threshold selection with improved level of evidence and a more robust and relevant database (Appendix Table A1). As procedures and treatment options have evolved, this 2020 update reviews and analyzes the expanding evidence base and provides guidance relating to differences between the lateral and dorsal surgical procedures for minimally invasive surgical sacroiliac joint fusion.

A Review and Algorithm in the Diagnosis and Treatment of Sacroiliac Joint Pain

INTRODUCTION

The sacroiliac joint (SIJ) has been estimated to contribute to pain in as much as 38% of cases of lower back pain. There are no clear diagnostic or treatment pathways. This article seeks to establish a clearer pathway and algorithm for treating patients.

METHODS

The literature was reviewed in order to review the biomechanics, as well as establish the various diagnostic and treatment options. Diagnostic factors addressed include etiology, history, physical exam, and imaging studies. Treatment options reviewed include conservative measures, as well as interventional and surgical options.

RESULTS

Proposed criteria for diagnosis of sacroiliac joint dysfunction can include pain in the area of the sacroiliac joint, reproducible pain with provocative maneuvers, and pain relief with a local anesthetic injection into the SIJ. Conventional non-surgical therapies such as medications, physical therapy, radiofrequency denervation, and direct SI joint injections may have some limited durability in therapeutic benefit. Surgical fixation can be by a lateral or posterior/posterior oblique approach with the literature supporting minimally invasive options for improving pain and function and maintaining a low adverse event profile.

CONCLUSION

SIJ pain is felt to be an underdiagnosed and undertreated element of LBP. There is an emerging disconnect between the growing incidence of diagnosed SI pathology and underwhelming treatment efficacy of medical treatment. This has led to an increase in SI joint fixation. We have created a clearer diagnostic and treatment pathway to establish an algorithm for patients that can include conservative measures and interventional techniques once the diagnosis is identified.

Sacroiliac joint fusion VS conservative management for chronic low back pain attributed to the sacroiliac joint: A protocol for systematic review and meta analysis

INTRODUCTION

Low back pain (LBP) is high prevalent and it is the leading cause of years lived with disability in both developed and developing countries. The sacroiliac joint (SIJ) is a common reason that caused LBP. At present, the treatment of chronic LBP attributed to SIJ is mainly conservative treatment and surgical treatment. However, there are still controversies between the 2 treating methods, and there is no recognized standard of treatment or surgical indications. Recent publications indicated that minimally invasive sacroiliac joint arthrodesis was safe and more effective improving pain, disability, and quality of life compared with conservative management in 2 years follow-up, which re-raise the focus of sacroiliac joints fusion. This paper will systematically review the available evidence, comparing the effectiveness of sacroiliac joint fusion and conservative therapy for the treatment of gait retraining for patients suffered from LBP attributed to the sacroiliac joint.

METHOD AND ANALYSIS

A systematic review and meta-analysis of relevant studies in Pubmed, Embase, SCOPUS, and Cochrane Library will be synthesized. Inclusion criteria will be studies evaluating clinical outcomes (i.e., changes to pain and/or function) comparing sacroiliac joint fusion and conservative therapy in populations sacroiliac join related LBP; studies with less than 10 participants in total will be excluded. The primary outcomes measured will be pain score, Oswestry Disability Index (ODI), and adverse events during treatment. Review Manager (Revman; Version 5.3) software will be used for data synthesis, sensitivity analysis, meta-regression, subgroup analysis, and risk of bias assessment. A funnel plot will be developed to evaluate reporting bias and Begg and Egger tests will be used to assess funnel plot symmetries. We will use the Grading of Recommendations Assessment, Development and Evaluation system to assess the quality of evidence.

ETHICS AND DISSEMINATION

Our aim is to publish this systematic review and meta-analysis in a peer-reviewed journal. Our findings will provide information comparing the efficacy and safety comparing sacroiliac joint fusion and non-surgical treatment for patients with LBP attributed to the sacroiliac joint. This review will not require ethical approval as there are no issues about participant privacy.

Comparative analysis of the lateral and posterolateral trajectories for fixation of the sacroiliac joint-a cadaveric study

Background

A number of minimally invasive sacroiliac (SI) joint fusion solutions for placing implants exist, with reduced post-operative pain and improved outcomes compared to open procedures. The objective of this study was to compare two MIS SI joint fusion approaches that place implants directly across the joint by comparing the ilium and sacrum bone characteristics and SI joint separation along the implant trajectories.

Methods

Nine cadaveric specimens (n = 9) were CT scanned and the left and right ilium and sacrum were segmented. The bone density, bone volume fraction, and SI joint gap distance were calculated along lateral and posterolateral trajectories and compared using analysis of variance between the two orientations.

Results

Iliac bone density, indicated by the mean Hounsfield Unit, was significantly greater for each lateral trajectory compared to posterolateral. The volume of cortical bone in the ilium was greater for the middle lateral trajectory compared to all others and for the top and bottom lateral trajectories compared to both posterolateral trajectories. Cortical density was greater in the ilium for all lateral trajectories compared to posterolateral. The bone fraction was significantly greater in all lateral trajectories compared to posterolateral in the ilium. No differences in cortical volume, cortical density, or cancellous density were found between trajectories in the sacrum. The ilium was significantly greater in density compared with the sacrum when compared irrespective of trajectory (p < 0.001). The posterolateral trajectories had a significantly larger SI joint gap than the lateral trajectories (p < 0.001).

Conclusion

Use of the lateral approach for minimally invasive SI fusion allows the implant to interact with bone across a significantly smaller joint space. This interaction with increased cortical bone volume and density may afford better fixation with a lower risk of pull-out or implant loosening when compared to the posterolateral approach.

Minimally Invasive Sacroiliac Joint Fusion: A Lateral Approach Using Triangular Titanium Implants and Navigation

Background:

Minimally invasive sacroiliac (SI) joint fusion is indicated for low back pain from the SI joint that is due to degenerative sacroiliitis and/or sacroiliac joint disruption. This technique is safe and effective in relieving pain uncontrolled by nonoperative management^1-4. There is some controversy, but there continues to be increasing evidence of effectiveness.

Description:

This procedure is performed, with the patient under general anesthesia and in the prone position, using fluoroscopy or 3-dimensional (3D) navigation such as cone-beam computed tomographic (CT) imaging. After navigation setup, a navigated probe is used to approximate the desired location of each implant and trajectory. These positions are marked on the skin, and the skin is incised. A 3 to 5-cm lateral incision is made. The gluteal fascia is bluntly dissected to the outer table of the ilium. A guide pin is passed across the SI joint and into the center of the sacrum lateral to the neural foramina, which is confirmed with imaging. This is then drilled and broached. Triangular titanium rods are placed. Typically, 3 implants are placed, 2 in S1 and 1 in S2. Multiplanar postplacement imaging of the pelvis is obtained. The wound is irrigated and closed in layers.

Alternatives:

Nonsurgical alternatives have been reported to include pharmacological therapies, such as nonsteroidal anti-inflammatory drugs, therapeutic SI joint blocks⁵, and physical therapy, such as core stabilization, orthotics (SI belts), and radiofrequency ablation^1,2,6-8. The surgical alternative is an open anterior or posterior approach with SI joint arthrodesis. The anterior approach differs by the resection of the SI joint cartilage, the use of a plate or screws across the joint for stabilization, and the packing of bone graft to facilitate fusion⁹. These are more morbid and have a much longer recovery.

Rationale:

Conservative management for SI joint pain is inadequate for all patients. Having 3 of 5 positive physical examination maneuvers⁷, having confirmatory diagnostic block(s)¹⁰, and ruling out the hip or spine as the pain generator provide a success rate of >80%. These patients have early and sustained clinically important and significantly improved outcomes across varying measures compared with conservative treatment^1-4,11,12.

Expected Outcomes:

Patients can expect to experience decreased pain, reduced disability, increased daily function, and improved quality of life soon after the procedure is performed. These patients typically have an improvement of ≥50% in the Oswestry Disability Index score and a clinically significant decrease in visual analog pain scores¹³. The procedure appears durable through at least 5 years¹⁴. Complete pain relief is rare, but clinically important improvement is typical.

Important Tips:

Proper setup of the navigation system or fluoroscopy is needed to ensure accurate starting points.

For 3D navigation, use a reference pin in the contralateral posterior superior iliac spine.

Although navigation is used, radiographic images are made periodically to confirm proper placement of guide pins and implants. Images provide the greatest benefit when establishing navigation, after guide-pin placement when an outlet view allows for evaluation of pin depth, and after implant placement to confirm proper placement.

Blood loss is generally low, but care should be taken to avoid vascular injury. Although rare, improper placement has led to injury of the superior gluteal artery¹⁵ and iliac artery¹⁶. This can be avoided by staying in bone.

Proper placement of the implant is imperative in this procedure. There is the potential for nerve injury with improper placement of the implant: an L5 nerve injury if the implant is too ventral or an S1 or S2 nerve injury if the implant is too deep and into the foramen. Revision surgery is commonly due to nerve root impingement and/or malpositioning.

Preoperative 3D imaging is indicated when it is necessary to rule out differential diagnoses that mimic SI joint pain. This enables the surgeon to rule out intrapelvic pathology, assess sacral bone density¹⁷, and identify dysmorphic sacra or transitional vertebrae.

iFuse Implant System for Treating Chronic Sacroiliac Joint Pain: A NICE Medical Technology Guidance

Treatment and management of sacroiliac joint pain is often non-surgical, involving packages of care that can include analgesics, physiotherapy, corticosteroid injections and radiofrequency ablation. Surgical intervention is considered when patients no longer respond to conservative management. The iFuse Implant System is placed across the sacroiliac joint using minimally invasive surgery, stabilising the joint and correcting any misalignment or weakness that can cause chronic pain. The iFuse system was evaluated in 2018 by the UK National Institute for Health and Care Excellence (NICE) as part of the Medical Technologies Evaluation Programme (MTEP). Clinical evidence for iFuse suggests improved pain, Oswestry disability index (ODI) and quality of life compared to non-surgical management. The company (SI-Bone^®) submitted two cost models indicating that iFuse was cost saving compared with open surgery and non-surgical management. Clinicians advised that non-surgical management was the most appropriate comparator and Cedar (a health technology research centre) made changes to the model to test the impact of higher acquisition and procedure costs. Cedar found iFuse to be cost incurring by approximately £560 per patient at 7 years. During the consultation period, the company reduced the cost of some iFuse consumables, and Cedar extended the time horizon to test the assumption that iFuse would become cost saving over time. These changes indicated that iFuse becomes cost saving at 8 years (approximately £129 per patient), after which the cost saving continues to increase. NICE published guidance in October 2018 recommending that the case for adoption of the iFuse system in the UK National Health Service (NHS) was supported by the evidence.

Minimally Invasive Sacroiliac Joint Fusion: The Current Evidence

Background

Fusion of the sacroiliac (SI) joint as a treatment for low back pain remains controversial. The purpose of this manuscript is to review the current literature and clinical outcomes of SI joint fusion surgery.

Methods

We conducted a literature review and included studies with the term "sacroiliac joint fusion" that had at least 12 months of clinical follow-up, reported on minimally invasive techniques, and included patient-reported outcome measures.

Results

Two approach types (dorsal and lateral) and numerous different implant manufacturers were identified. Most studies included level 4 data, with a small number of level 2 prospective cohort studies and 2 prospective level 1 studies. Every reviewed study reported clinical benefit in terms of improved pain scores or improvement in validated disability measures. Complication rates were low.

Conclusions

Minimally invasive SI joint fusion provides clinically significant improvement in pain scores and disability in most patients, across multiple studies and implant manufacturers.

Level of Evidence

5.

Clinical Relevance

Emerging evidence in support of SI joint fusion indicates that clinicians should examine the SI joint and include SI joint pain in their differential diagnosis for low back pain patients.

The Safety Profile of Percutaneous Minimally Invasive Sacroiliac Joint Fusion

STUDY DESIGN

Literature review.

OBJECTIVES

Systematic review of the existing literature to determine the safety of minimally invasive (MI) sacroiliac (SI) joint fusion through the determination of the rate of procedural and device-related intraoperative and postoperative complications.

METHODS

All original studies with reported complication rates were included for analysis. Complications were defined as procedural if secondary to the MI surgery and device related if caused by placement of the implant. Complication rates are reported using descriptive statistics. Random-effects meta-analysis was performed for preoperative and postoperative Visual Analog Score (VAS) pain ratings and Oswestry Disability Index (ODI) scores.

RESULTS

Fourteen studies of 720 patients (499 females/221 males) with a mean follow-up of 22 months were included. Ninety-nine patients (13.75%) underwent bilateral SI joint arthrodesis resulting in a total of 819 SI joints fused. There were 91 reported procedural-related complications (11.11%) with the most common adverse event being surgical wound infection/drainage (n = 17). Twenty-five adverse events were attributed to be secondary to placement of the implant (3.05%) with nerve root impingement (n = 13) being the most common. The revision rate was 2.56%. MI SI joint fusion reduced VAS scores from 82.42 (95% confidence interval [CI] 79.34-85.51) to 29.03 (95% CI 25.05-33.01) and ODI scores from 57.44 (95% CI 54.73-60.14) to 29.42 (95% CI 20.62-38.21).

CONCLUSIONS

MI SI joint fusion is a relatively safe procedure but is not without certain risks. Further work must be done to optimize the procedure's complication profile. Possible areas of improvement include preoperative patient optimization, operative technique, and use of intraoperative real-time imaging.

Minimally Invasive Sacroiliac Joint Fusion Using Triangular Titanium versus Cylindrical Threaded Implants: A Comparison of Patient-Reported Outcomes

BACKGROUND

Minimally invasive fusion of the sacroiliac (SI) joint has gained popularity for the treatment of refractory dysfunction. The purpose of this study was to compare the clinical outcomes of minimally invasive SI joint fusion between cylindrical threaded implants (CTIs) and triangular dowel implants (TDIs).

METHODS

We retrospectively reviewed consecutive patients who underwent SI joint fusions with either CTIs or TDIs. Data collected included patient demographics, perioperative data, and all patient-reported outcomes (PROs) including postoperative visual analog scale (VAS), Oswestry Disability Index, and Short Form-12 at 6 months and 1 year. The change from baseline PROs between the cohorts was analyzed as the primary outcome. Secondary outcomes included revision rates and time to revision between the two cohorts. A P value <0.05 was considered significant.

RESULTS

One hundred fifty-six consecutive patients underwent SI joint fusion, 74 patients with CTIs and 82 with TDIs. There was a significant difference in procedure length with CTI averaging 60.0 minutes (confidence interval: 55.7-64.3) and TDI averaging 41.2 minutes (confidence interval: 38.4-43.9, P < 0.0005). In both cohorts, there was a significant improvement in all PROs at 6 months when compared with preoperative values. However, when compared, there was no significant difference between the cohorts at 6-month follow-up or 1-year follow-up for either VAS-back, VAS-leg, Oswestry Disability Index, or Short Form-12. A 6.1% revision rate in the CTI cohort was observed compared with a 2.4% revision rate in the TDI cohort (P = 0.11).

CONCLUSIONS

SI joint fusions with TDI or CTI offer a significant improvement in pain, disability, and quality of life. However, no difference was observed between devices to suggest superior clinical outcomes. Increased revision rates in the Rialto group warrants further investigation.

A biomechanical investigation of the sacroiliac joint in the setting of lumbosacral fusion: impact of pelvic fixation versus sacroiliac joint fixation

OBJECTIVE

The sacroiliac joint (SIJ) is a known source of low-back pain. Randomized clinical trials support sacroiliac fusion over conservative management for SIJ dysfunction. Clinical studies suggest that SIJ degeneration occurs in the setting of lumbosacral fusions. However, there are few biomechanical studies to provide a good understanding of the effect of lumbosacral fusion on the SIJ. In the present study, researchers performed a biomechanical investigation to discern the effect of pelvic versus SIJ fixation on the SIJ in lumbosacral fusion.

METHODS

Seven fresh-frozen human cadaveric specimens were used. There was one intact specimen and six operative constructs: 1) posterior pedicle screws and rods from T10 to S1 (PS); 2) PS + bilateral iliac screw fixation (BIS); 3) PS + unilateral iliac screw fixation (UIS); 4) PS + UIS + 3 contralateral unilateral SIJ screws (UIS + 3SIJ); 5) PS + 3 unilateral SIJ screws (3SIJ); and 6) PS + 6 bilateral SIJ screws (6SIJ). A custom-built 6 degrees-of-freedom apparatus was used to simulate three bending modes: flexion-extension (FE), lateral bending (LB), and axial rotation (AR). Range of motion (ROM) was recorded at L5-S1 and the SIJ.

RESULTS

All six operative constructs had significantly reduced ROM at L5-S1 in all three bending modes compared to that of the intact specimen (p < 0.05). In the FE mode, the BIS construct had a significant reduction in L5-S1 ROM as compared to the other five constructs (p < 0.05). SIJ ROM was greatest in the FE mode compared to LB and AR. Although the FE mode did not show any statistically significant differences in SIJ ROM across the constructs, there were appreciable differences. The PS construct had the highest SIJ ROM. The BIS construct reduced bilateral SIJ ROM by 44% in comparison to the PS construct. The BIS and 6SIJ constructs showed reductions in SIJ ROM nearly equal to those of the PS construct. UIS and 3SIJ showed an appreciable reduction in unfused SIJ ROM compared to PS.

CONCLUSIONS

This investigation demonstrated the effects of various fusion constructs using pelvic and sacroiliac fixation in lumbosacral fusion. This study adds biomechanical evidence of adjacent segment stress in the SIJ in fusion constructs extending to S1. Unilateral pelvic fixation, or SIJ fusion, led to an appreciable but nonsignificant reduction in the ROM of the unfused contralateral SIJ. Bilateral pelvic fixation showed the greatest significant reduction of movement at L5-S1 and was equivalent to bilateral sacroiliac fusion in reducing SIJ motion.

Long-Term Prospective Clinical And Radiographic Outcomes After Minimally Invasive Lateral Transiliac Sacroiliac Joint Fusion Using Triangular Titanium Implants

BACKGROUND

Accumulating evidence supports the long-term safety and effectiveness of minimally invasive sacroiliac joint fusion (SIJF) for sacroiliac joint dysfunction.

OBJECTIVE

To report 5-year clinical and radiographic follow-up in patients undergoing SIJF using triangular titanium implants (TTI).

METHODS

One hundred and three subjects at 12 centers treated with SIJF using TTI in two prospective clinical trials (NCT01640353 and NCT01681004) were enrolled and followed in the current study (NCT02270203) with clinic visits at 3, 4 and 5 years. CT scans performed at 5 years were compared to prior CT scans (at 1 or 2 years) by an independent radiologist.

RESULTS

Compared to baseline scores, SIJ pain scores at 5 years decreased by a mean of 54 points, disability scores (Oswestry Disability Index) decreased by 26 points, and quality of life scores (EuroQOL-5D time trade-off index) increased by 0.29 points (0-1 scale) (all p<0.0001). Satisfaction rates were high and the proportion of subjects taking opioids decreased from 77% at baseline to 41% at 5-year follow-up. Independent radiographic analysis showed a high rate (98%) of bone apposition to implants on both the sacral and iliac sides of the SI joint, with a high rate of bony bridging (87%) and a low rate of radiolucencies suggestive of loosening (5%).

CONCLUSION

A 5-year follow-up showed continued excellent clinical responses in patients with SIJ pain treated with SIJF using triangular titanium implants along with a high rate (88%) of joint fusion.

LEVEL OF EVIDENCE

Level II.

Technical variation of trans-articular sacroiliac joint (SIJ) fusion using three screws considering the effects of sacral dysplasia in patients with non-traumatic SIJ pain

Background

This study evaluated the technical adequacy of trans-articular sacroiliac joint (SIJ) fusion using three screws for non-traumatic SIJ pain, considering different grades of sacral dysplasia.

Methods

Cadaveric CT data of unilateral sacropelvic complexes for 72 individuals (53.4 ± 8.4 years) were selected. A 3D model was reformatted into the plain lateral radiograph to mark the articular surface of the SIJ. Subjects were classified into dysplastic (DYS) and non-dysplastic sacrum (NDS) groups. Proximal (PS), middle (MS), and distal screws (DS) with 10-mm diameter were virtually introduced to the iliac bone and the SIJ on the lateral image with a 5-mm safety margin. On a corresponding axial image, each screw was advanced vertically to the sagittal plane with the same safety margin. The entry points for each screw to the endplate of S1 (S2) and to the corresponding anterior sacral margin on the lateral image were measured, along with the maximal screw lengths on the axial image. Whether each screw passed through the SIJ was determined. Different types of sacral dysplasia and screws were compared statistically.

Results

Thirty-eight (26.4%) cases were DYS, and 106 (73.6%) were NDS. The entry points of all screws were significantly more distal in DYS than in NDS groups. The PS and MS screw lengths differed significantly between the 2 groups. Incidences of short sacral fixation (< 10 mm) were significantly higher for the DS in both NDS (38.7%) and DYS (39.5%) groups. Incidences of screw pass were lowest for the MS in both NDS (43.4%) and DYS (47.4%) groups.

Conclusions

Sacral dysplasia locates the SIJ more distally and therefore affects the entry point locations and screw lengths for all screws in trans-articular SIJ fusion, compared with a non-dysplastic sacrum. Moreover, three-screw fixation risks the development of unstable DS fixation and a high extra-articular fixation rate in MS.

Building a Collaborative Model of Sacroiliac Joint Dysfunction and Pelvic Girdle Pain to Understand the Diverse Perspectives of Experts

BACKGROUND

Pelvic girdle pain (PGP) and sacroiliac joint (SIJ) dysfunction/pain are considered frequent contributors to low back pain (LBP). Like other persistent pain conditions, PGP is increasingly recognized as a multifactorial problem involving biological, psychological, and social factors. Perspectives differ between experts and a diversity of treatments (with variable degrees of evidence) have been utilized.

OBJECTIVE

To develop a collaborative model of PGP that represents the collective view of a group of experts. Specific goals were to analyze structure and composition of conceptual models contributed by participants, to aggregate them into a metamodel, to analyze the metamodel's composition, and to consider predicted efficacy of treatments.

DESIGN

To develop a collaborative model of PGP, models were generated by invited individuals to represent their understanding of PGP using fuzzy cognitive mapping (FCM). FCMs involved proposal of components related to causes, outcomes, and treatments for pain, disability, and quality of life, and their connections. Components were classified into thematic categories. Weighting of connections was summed for components to judge their relative importance. FCMs were aggregated into a metamodel for analysis of the collective opinion it represented and to evaluate expected efficacy of treatments.

RESULTS

From 21 potential contributors, 14 (67%) agreed to participate (representing six disciplines and seven countries). Participants' models included a mean (SD) of 22 (5) components each. FCMs were refined to combine similar terms, leaving 89 components in 10 categories. Biomechanical factors were the most important in individual FCMs. The collective opinion from the metamodel predicted greatest efficacy for injection, exercise therapy, and surgery for pain relief.

CONCLUSIONS

The collaborative model of PGP showed a bias toward biomechanical factors. Most efficacious treatments predicted by the model have modest to no evidence from clinical trials, suggesting a mismatch between opinion and evidence. The model enables integration and communication of the collection of opinions on PGP.

Randomized Trial of Sacroiliac Joint Arthrodesis Compared with Conservative Management for Chronic Low Back Pain Attributed to the Sacroiliac Joint

BACKGROUND

Sacroiliac joint pain is increasingly recognized as a cause of low back pain. We compared the safety and effectiveness of minimally invasive sacroiliac joint arthrodesis using triangular titanium implants and conservative management in patients with chronic sacroiliac joint pain.

METHODS

This study was a prospective, multicenter randomized controlled trial of adults with chronic sacroiliac joint pain assigned to either conservative management or sacroiliac joint arthrodesis with triangular titanium implants. The study end points included self-rated low back pain (visual analog scale [VAS]), back dysfunction (Oswestry Disability Index [ODI]), and quality of life. Ninety percent of subjects in both groups completed the study.

RESULTS

Between June 6, 2013, and May 15, 2015, 103 subjects were randomly assigned to conservative management (n = 51) or sacroiliac joint arthrodesis (n = 52). At 2 years, the mean low back pain improved by 45 points (95% confidence interval [CI], 37 to 54 points) after sacroiliac joint arthrodesis and 11 points (95% CI, 2 to 20 points) after conservative management, with a mean difference between groups of 34 points (p < 0.0001). The mean ODI improved by 26 points (95% CI, 21 to 32 points) after sacroiliac joint arthrodesis and 8 points (95% CI, 2 to 14 points) after conservative management, with a mean difference between groups of 18 points (p < 0.0001). Parallel improvements were seen in quality of life. In the sacroiliac joint arthrodesis group, the prevalence of opioid use decreased from 56% at baseline to 33% at 2 years (p = 0.009), and no significant change was observed in the conservative management group (47.1% at baseline and 45.7% at 2 years). Subjects in the conservative management group, after crossover to the surgical procedure, showed improvements in all measures similar to those originally assigned to sacroiliac joint arthrodesis. In the first 6 months, the frequency of adverse events did not differ between groups (p = 0.664). By month 24, we observed 39 severe adverse events after sacroiliac joint arthrodesis, including 2 cases of sacroiliac joint pain, 1 case of a postoperative gluteal hematoma, and 1 case of postoperative nerve impingement. The analysis of computed tomographic (CT) imaging at 12 months after sacroiliac joint arthrodesis showed radiolucencies adjacent to 8 implants (4.0% of all implants).

CONCLUSIONS

For patients with chronic sacroiliac joint pain due to joint degeneration or disruption, minimally invasive sacroiliac joint arthrodesis with triangular titanium implants was safe and more effective throughout 2 years in improving pain, disability, and quality of life compared with conservative management.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Mini-open sacroiliac joint fusion with direct bone grafting and minimally invasive fixation using intraoperative navigation

Background

Describe a novel technique for sacroiliac arthrodesis using intraoperative navigation, direct bone grafting, and minimally invasive implants. Report on the outcomes of the first cohort of these patients.

Methods

Institutional review board (IRB) approved, single center, two surgeon, retrospective study.

Results

All patients were 18 years or older, primary sacroiliac fusions, and underwent novel technique described. Fifty patients underwent 57 surgeries. Twelve male/38 female patients. All received three sacroiliac implants. Average blood loss 42.8 mL. Average length of stay 1.9 nights. Average follow-up 13.96±13 months. Statistically significant improvements in Visual Analogue Scale (VAS) scores (<0.001) for all time periods 6 weeks, 3 months, 6 months, 12 months compared to preop. Other outcomes scores [Oswestry Disability Index (ODI), and Denver Sacroiliac Joint Questionnaire (DSIJQ)] also showed a general trend for clinical improvement at all postoperative time periods. Of 2/57 (3.5%) complications were identified. No patients required surgical revision within the study window.

Conclusions

Limited open sacroiliac arthrodesis using minimally invasive implants, intraoperative navigation, and direct open bone grafting is safe and demonstrates clinical benefit, similar to other techniques for minimally invasive sacroiliac arthrodesis. There is potential for improved long-term outcomes from increased union rates.

Keywords

Sacroiliac dysfunction; minimally invasive sacroiliac fusion; open sacroiliac fusion; navigation.

Physiological in vitro sacroiliac joint motion: a study on three-dimensional posterior pelvic ring kinematics

The sacroiliac joint (SIJ) is a well-known source of low back and pelvic pain, of increasing interest for both conservative and surgical treatment. Alterations in the kinematics of the pelvis have been hypothesized as a major cause of SIJ-related pain. However, definitions of both the range and the extent of physiological movement are controversial, and there are no clear baseline data for pathological alterations. The present study combined a novel biomechanical setup allowing for physiological motion of the lumbosacral transition and pelvis without restricting the SIJ movement in vitro, combined with optical image correlation. Six fresh human pelvises (81 ± 10 years, three females, three males) were tested, with bodyweight-adapted loading applied to the fifth lumbar vertebra and both acetabula. Deformation at the lumbopelvises was determined computationally from three-dimensional image correlation data. Sacroiliac joint motion under the loading of 100% bodyweight primarily consisted of a z-axis rotation (0.16°) and an inferior translation of the sacrum relative to the ilium (0.32 mm). Sacroiliac joint flexion-extension rotations were minute (< 0.02°). Corresponding movements of the SIJ were found at the lumbosacral transition, with an anterior translation of L5 relative to the sacrum of -0.97 mm and an inferior translation of 0.11 mm, respectively. Moreover, a flexion of 1.82° was observed at the lumbosacral transition. Within the innominate bone and at the pubic symphysis, small complementary rotations were seen around a vertical axis, accounting for -0.10° and 0.11°, respectively. Other motions were minute and accompanied by large interindividual variation. The present study provides evidence of different SIJ motions than reported previously when exerted by physiological loading. Sacroiliac joint kinematics were in the sub-degree and sub-millimeter range, in line with previous in vivo and in vitro findings, largely limited to the sagittal rotation and an inferior translation of the sacrum relative to the ilium. This given physiological loading scenario underlines the relevance of the lumbosacral transition when considering the overall motion of the lumbopelvis, and how relatively little the other segments contribute to overall motion.

Radiofrequency denervation for treatment of sacroiliac joint pain-comparison of two different ablation techniques

The radiofrequency treatment (RFD) for sacroiliac joint pain (SIP) is well-established, but there is still scarce evidence on its clinical outcome. The classical monopolar RFD is limited by a high recurrence rate. This might be caused by an incomplete denervation of the dorsal rami. The Simplicity III probe was invented to optimise pain fibre recruitment by its multi-electrode design. However, the clinical superiority of this procedure was never proven. The aim of this study was to illustrate the effectiveness of RFD and to compare both denervation techniques. One hundred twenty-one patients were included, and their clinical course was analysed. Fifty-seven patients received conventional treatment with multiple percutaneous monopolar RFDs (monolesion probe group, MoLG) and 64 patients with the Simplicity III probe (multilesion probe group, MuLG). All patients were followed 1, 3, 6 and 12 s after RFD. Clinical outcome scores were analysed (numeric pain rating scale (NPRS), Roland-Morris Disability Questionnaire, Oswestry Disability Index (ODI), Odom's criteria, Short Form 36 score). The MuLG showed a clearly advanced improvement concerning the clinically relevant pain relief (≥ 50%) (1 month/3 months /6 months/12 months = 72%, 55%, 36%, 27% vs. 1 month/3 months/6 months/12 months = 39%, 28%, 16%, 11%) as well as an advanced improvement of pain-associated disability and a higher satisfaction rating compared to the MoLG (NPRS_MuLG__preop = 8,3; NPRS_MuLG__12months = 5.8; NPRS_{MoLG_preop} = 7,7; NPRS_{MoLG_12months} = 5.8; ODI_{MuLG_preop} = 52; ODI_{MuLG_12months} = 42; ODI_{MoLG_preop} = 52; ODI_{MoLG_12months} = 47; ODOMS_{MuLG_good/excellent} = 54%; ODOMS_{MoLG_good/excellent} = 28%). RFD of the SIP with the Simplicity III probe is effective and delivers a distinct pain reduction even after 1 year of treatment. This technique shows clear advantages compared to the conventional monolesion technique and is a useful treatment for patients with recurrent SIP.

Risk Factors for Continued Opioid Use in Conservative Versus Surgical Management of Low Back Pain Originating From the Sacroiliac Joint

STUDY DESIGN

Secondary analysis of data from a randomized controlled trial.

OBJECTIVES

To identify risk factors for continued opioid use after conservative management (CM) or minimally invasive surgical management (MISM) of low back pain (LBP) originating from the sacroiliac joint.

METHODS

Patients were randomized either to CM (n = 49) or MISM (n = 52). We documented opioid use, pain intensity (visual analogue scale [VAS]), Oswestry Disability Index (ODI), and the Zung depression score (Zung Self-Rating Depression Scale) at baseline and at months 3 and 6 after treatment initiation.

RESULTS

Compared with opioid nonusers, opioid users at baseline had higher mean levels of disability (ODI 61.5, standard deviation [SD] 13.3 vs ODI 51.5, SD 12.8; P < .01) and higher depression scores (Zung 48.5, SD 8.5, vs Zung 42.2, SD 7.2; P < .01). At 6 months, opioid users had higher 6-month pain levels (VAS 60.4, SD 24.0, vs VAS 42.4, SD 28.2; P < .01), higher disability scores (ODI 50.5, SD 16.2, vs ODI 32.7, SD 19.3; P < .01) and higher depression scores (Zung 47.6, SD 8.0, vs Zung 38.8, SD 8.9; P < .01). Risk factors for continued opioid use at 6 months were patient age (odds ratio [OR] for age = 0.91; P = .02) and an increase in LBP (OR 1.08; P = .02) in the CM group and a lack of improvement in depression scores (OR 1.12; P = .03) in the MISM group.

CONCLUSIONS

In our patient cohort, the risk of continued opioid use in the treatment of LBP increased not only with pain intensity but also with levels of depression during the course of treatment.

Biomechanical evaluation of sacroiliac joint fixation with decortication

BACKGROUND CONTEXT

Fusion typically consists of joint preparation, grafting, and rigid fixation. Fusion has been successfully used to treat symptomatic disruptions of the sacroiliac joint (SIJ) and degenerative sacroiliitis using purpose-specific, threaded implants. The biomechanical performance of these systems is important but has not been studied.

PURPOSE

The objective of this study was to compare two techniques for placing primary (12.5 mm) and secondary (8.5 mm) implants across the SIJ.

STUDY DESIGN

This is a human cadaveric biomechanical study of SIJ fixation.

MATERIALS AND METHODS

Pure-moment testing was performed on 14 human SIJs in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) with motion measured across the SIJ. Specimens were tested intact, after destabilization (cutting the pubic symphysis), after decortication and implantation of a primary 12.5-mm implant at S1 plus an 8.5-mm secondary implant at either S1 (S1-S1, n=8) or S2 (S1-S2, n=8), after cyclic loading, and after removal of the secondary implant. Ranges of motion (ROMs) were calculated for each test. Bone density was assessed on computed tomography and correlated with age and ROM. This study was funded by Zyga Technology but was run at an independent biomechanics laboratory.

RESULTS

The mean±standard deviation intact ROM was 3.0±1.6° in FE, 1.5±1.0° in LB, and 2.0±1.0° in AR. Destabilization significantly increased the ROM by a mean 60%-150%. Implantation, in turn, significantly decreased ROM by 65%-71%, below the intact ROM. Cyclic loading did not impact ROM. Removing the secondary implant increased ROM by 46%-88% (non-significant). There was no difference between S1-S1 and S1-S2 constructs. Bone density was inversely correlated with age (R=0.69) and ROM (R=0.36-0.58).

CONCLUSIONS

Fixation with two threaded rods significantly reduces SIJ motion even in the presence of joint preparation and after initial loading. The location of the secondary 8.5-mm implant does not affect construct performance. Low bone density significantly affects fixation and should be considered when planning fusion constructs. Findings should be interpreted in the context of ongoing clinical studies.

Impact of Iliac Instrumentation on the Quality of Life of Patients With Adult Spine Deformity

STUDY DESIGN

Retrospective comparative analysis of data collected prospectively in an adult spine deformity (ASD) multicenter database.

OBJECTIVE

To evaluate the impact of the iliac screws on the quality of life of ASD patients compared with those instrumented above the pelvis (L5/S1/S2).

SUMMARY OF BACKGROUND DATA

The impact on patient's daily activities and functions, of immobilizing the sacroiliac joint with iliac screws for the treatment of ASD is still underexplored.

METHODS

Inclusion criteria were ASD patients with a long arthrodesis of at least eight levels and whose lowest instrumented vertebrae (LIV) were L5 or below. We analyzed the following preoperative and 2 years' follow-up variables: age, Cobb angle, coronal and sagittal alignment, number of instrumented levels, Oswestry Disability Index (ODI), Core Outcome Measures Index (COMI), Scoliosis Research Society-22 (SRS-22), and Short Form 36 (SF-36) questionnaires. Statistical analysis was performed with Mann-Whitney U test, and Wilcoxon test.

RESULTS

A total of 129 patients were included, and separated into two groups: "Iliac Yes," with the LIV at the Ilium (N = 104), and "iliac No," with the LIV at L5/S1/S2 (N = 25). Patients instrumented with Iliac screws were older (x = 66 vs. 56 yr, P = 0.008), and had lower Cobb magnitude (x = 31° vs. 45°, P = 0.019). No statistically significant differences were found in the health related quality of life (HRQOL) questionnaires prior to surgery or at 2-years' follow up. The "Iliac Yes" group significantly improved all radiographic and HRQOL scores parameters 2 years after surgery (P < 0.005). While the "Iliac No" group failed to significantly improve (coronal balance, sagittal vertical axis, SF-36 Physical functioning, SF-36 General health, and COMI) (P > 0.05) CONCLUSION.: ASD patients instrumented with iliac screws significantly improved all their HRQOL questionnaires 2 years after surgery. The 2 years' postoperative HRQOL scores were similar in both groups, regardless of the sacroiliac joint immobilization. Therefore, with the currently available tools, we cannot state that iliac instrumentation has a negative influence on patient's quality of life.

LEVEL OF EVIDENCE

4.