OBJECTIVE: The demand for SIJ fusion among obese patients has grown substantially. However, the clinical relevance of obesity in the context of SI joint fusion has not been well investigated specifically, whether there is a BMI cutoff above which the benefit-risk ratio is low.
METHODS: Adult patients ≥ 21 years of age who underwent minimally invasive SIJ fusion between 2020 and 2023. Participants were classified using the National Institutes for Health body mass index (BMI). Patients with a BMI of 30 to 39 with no significant comorbidity are considered obese, patients with a BMI of 35 to 39 with a significant comorbidity or a BMI of 40 or greater are considered morbidly obese. All subjects completed the Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) at baseline and 12 months. One-way analysis of variance was used to examine the impact of BMI category on score changes.
RESULTS: Overall, mean VAS improved at 12 months by 2.5 points (p < .006). Over the 12-month follow-up period, BMI category did not impact mean improvement in VAS (ANOVA p = .08). Mean ODI at 12 months improved by 23.2 points (p < .001). BMI category did impact mean improvement in ODI (ANOVA p = .03).
CONCLUSIONS: This study demonstrates similar benefits across all BMI categories. This data suggests that obese patients do benefit from minimally invasive SIJ fusion, specifically the 35-40 BMI cohort of patients, and should not be denied this procedure based on arbitrary healthcare organizations BMI criteria.

BACKGROUND: Obesity is increasing. Previous studies have demonstrated an association between obesity and adverse events after lumbar fusion. There is limited evidence on the effect of obesity on minimally invasive SI joint fusion (SIJF) outcomes.
OBJECTIVE: The purpose of this study was to investigate the impact of obesity on patient-reported outcomes in patients undergoing SIJF surgery using triangular titanium implants (TTI).
METHODS: Retrospective cohort study based on four prospective clinical trials (INSITE [NCT01681004], SIFI [NCT01640353], iMIA [NCT01741025], and SALLY [NCT03122899]).
METHODS: Adult patients ≥18 years of age who underwent minimally invasive surgery (MIS) sacroiliac joint (SIJ) fusion between 2012 and 2021.
METHODS: Visual analog scale (VAS Pain), Oswestry Disability Index (ODI).
METHODS: Participants were classified using the National Institutes of Health body mass index (BMI). Patients with a BMI of 30 to 39 with no significant comorbidity are considered obese, patients with a BMI of 35 to 39 with a significant comorbidity or a BMI of 40 or greater are considered morbidly obese. All subjects underwent either minimally invasive SIJ fusion with TTI or nonsurgical management (INSITE and iMIA studies only). All subjects completed SIJ pain scale scores (measured with a 100-point VAS) and disability scores (measured with ODI) at baseline and at scheduled visits to 24 months. Repeated measures analysis of variance was used to examine the impact of BMI category on score changes.
RESULTS: In the SIJF group, mean SIJ pain improved at 24 months by 53.3 points (p<.0001). Over the 24-month follow-up period, BMI category did not impact mean improvement in SIJ pain scale score (repeated measures analysis of variance (ANOVA) p=.44). In the SIJF group, mean ODI at 24 months improved by 25.8 points (p<.0001). BMI category did not impact mean improvement in ODI (ANOVA p=.60). In the nonsurgical management (NSM) group, mean improvements in SIJ pain scale and ODI were clinically small (8.7 and 5.2 points, respectively) and not affected by BMI category (ANOVA p=.49 and .40).
CONCLUSIONS: This study demonstrates similar benefits and risks of minimally invasive SIJ fusion with TTI across all BMI categories. This analysis suggests that obese patients benefit from minimally invasive SIJ fusion and should not be denied this procedure based solely on elevated BMI.

OBJECTIVE: Pain reduction and improvement in quality of life with sacroiliac joint (SIJ) fusion.
METHODS: Chronic SIJ-associated pain; positive response to SIJ injection with local anesthetic; positive SIJ provocation tests; failed conservative therapy over 6 months.
METHODS: Non-SIJ-associated pain; tumor/infection/unstable fracture in the implantation area; malformations; tumor or osteolysis of the sacrum or ilium bone; active infection at the implantation site; allergy to metal components; secondary gain from illness, request for a pension; inadequately treated osteoporosis.
METHODS: Transarticular placement of Kirschner\'s wires through the SI joint via minimally invasive lateral approach. Guided preparation of implant site over Kirschner\'s wires and implantation of 3 triangular, transarticular titanium implants for SIJ fusion.
METHODS: Deep vein thrombosis prophylaxis. 3 weeks partial weight-bearing and then moving on to full weight-bearing. X‑ray controls at defined intervals. Physiotherapy.
RESULTS: We enrolled 26 patients who were followed up over the period of 4 years. The evaluated endpoints were low back pain on the visual analog scale (VAS 0-10), grade of disability with the Oswestry Disability Index (ODI) and quality of life with the EuroQOL-5D. At 4 years, mean low back pain improved compared to preoperative (VAS preoperative 8.4, VAS 4 years postoperative 4.6). Mean improvements in ODI (ODI preoperative 58.1, ODI 4 years postoperative 32.1) and EQ-5D (preoperative 0.5, after 4 years 0.7) could be evaluated over the long-term period of 4 years. Satisfaction rates were high and the proportion of subjects taking opioids decreased at the 4‑year follow-up (preoperative 82%, postoperative 39%). Implant loosening could not be detected on plain radiograph.
UNASSIGNED: OPERATIONSZIEL: Schmerzreduktion und Verbesserung der Lebensqualität durch ISG-Fusion.
UNASSIGNED: Chronische Iliosakralgelenk-assoziierte Schmerzen. Positive ISG-Testinfiltration mit Lokalanästhetikum. Positive ISG-Provokationstests. Erfolglose konservative Therapie über 6 Monate.
UNASSIGNED: Nicht ISG-assoziierte Beschwerden. Tumor/Infektion/instabile Fraktur im Implantationsareal. Fehlbildungen, Tumor oder Osteolyse des Sakrum- oder Iliumknochens. Aktive Infektion an der Behandlungsstelle. Allergie gegen Metallkomponenten. Sekundärer Krankheitsgewinn, Rentenbegehren. Unzureichend behandelte Osteoporose.
UNASSIGNED: Über einen lateralen minimal-invasiven Zugang bildwandlergesteuertes Einbringen von Kirschner-Drähten transartikulär durch das ISG in das Sakrum. Aufmeißeln des Implantatlagers über die Kirschner-Drähte und Einbringen von insgesamt 3 triangulären Titanimplantaten zur ISG-Arthrodese.
UNASSIGNED: Thromboseprophylaxe. Drei Wochen Teilbelastung und anschließend schrittweise Aufbelastung. Röntgenkontrollen in definierten Intervallen. Physiotherapie.
UNASSIGNED: Es wurden 26 konsekutive Patienten nach 48 Monaten untersucht. Die evaluierten Endpunkte waren tieflumbale Schmerzen entsprechend der visuellen Analogskala (VAS 0–10), Funktionseinschränkungen entsprechend Oswestry Disability Index (ODI) und Lebensqualität entsprechend EuroQOL-5D (EQ-5D). Nach 4 Jahren zeigte sich der Rückenschmerz im Vergleich zu präoperativ deutlich verbessert (VAS präoperativ 8,4, VAS 4 Jahre postoperativ 4,6). Die Funktionseinschränkungen zeigten sich rückläufig (ODI präoperativ 58,1, ODI 4 Jahre postoperativ 32,1), und ein Anstieg der Gesundheitsbewertung im EQ-5D war zu verzeichnen (präoperativ 0,5, nach 4 Jahren 0,7). Die Rate an Patienten, welche Opiate zur Schmerztherapie einnahmen, konnte deutlich gesenkt werden (präoperativ 82 %, postoperativ 39 %). Es zeigte sich keine Implantatlockerung im untersuchten Zeitraum.