This section describes efficacy outcomes from the published literature that the committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the interventional procedure overview.
4.1 In a randomised controlled trial (RCT) of 148 patients with sacroiliac (SI) joint dysfunction comparing minimally invasive SI joint fusion (n=102) with non-surgical management (NSM, n=46), success rates at 6 months were higher in the minimally invasive SI joint fusion group (81% [83/102] versus 26% [12/46]; Bayesian posterior probability of superiority >0.9999). (Success was defined as a composite of pain reduction from baseline visual analogue scale [VAS] pain score by at least 20 mm, absence of device-related serious adverse events or neurological worsening, and absence of surgical re-intervention.) In a prospective case series of 172 patients, intention-to-treat success rate was 80% (119/149) at 24 months (Bayesian posterior probability of superiority >0.9999).
4.2 In a systematic review of SI joint fusion in 430 patients, in those who had minimally invasive SI joint fusion (n=299), radiographically confirmed fusion rates (determined by CT or plain radiograph) were 13% to 100% (in 4 out of 9 studies) at a mean follow-up of 21 months. In the prospective case series of 172 patients, CT scan at 1‑year follow-up showed 97% bone adherence to at least 2 implants on both the iliac and sacral sides, with moderate rates of bone growth across the SI joint.
4.3 In the RCT of 148 patients, in the SI joint fusion group (n=102), mean joint pain (measured using a 0–100 VAS) improved from 82.3 at baseline to 30.4 at 6‑month follow-up (p<0.001), 28.3 at 12‑month follow-up (p<0.001) and 26.7 at the 24‑month follow-up (p<0.001). In the NSM group, mean SI joint pain improved from 82.2 at baseline to 70.3 at 6 months (p=0.001). Similarly, in the SI joint fusion group, mean Oswestry Disability Index (ODI) decreased from 57.2 at baseline to 29.9 at 6 months (p<0.001), 28.1 at 12 months (p<0.001) and 28.7 at 24 months (p<0.001). In the NSM group, mean ODI decreased from 56.0 at baseline to 51.6 at 6 months (p=0.06). There were clinically important improvements from baseline (VAS more than 20.0 points; ODI more than 15.0 points) and sustained clinical benefit (VAS more than 25.0 or less than 35.0 points; ODI more than 18.8 points) in the SI joint fusion group compared with patients in the NSM group.
4.4 In a systematic review and meta-analysis of 432 patients on minimally invasive SI joint fusion using a lateral transarticular approach, the random effects meta-analysis (RMA) mean pain score decreased from a baseline of 8.1 (95% confidence interval [CI] 7.8 to 8.4) to 2.8 (95% CI 2.4 to 3.2) at 6 months, 2.7 (95% CI 2.1 to 3.3) at 12 months and 2.0 (95% CI 1.4 to 2.5) at 24 months. ODI decreased from an RMA mean score of 56.6 (95% CI 51.0 to 61.5) at baseline, 30.3 (95% CI 22.5 to 38.0) at 6 months and 25.1 (95% CI 12.3 to 37.9) at 12 months.
4.5 In an RCT of 103 patients, SI joint function ratings (measured using the active straight leg raise test on a scale of 0 to 6) decreased statistically significantly more (p<0.0001) in the SI joint fusion group (from 4.0 to 2.0) than in the conservative management group (from 3.8 to 3.7). The proportion of patients who could raise the leg with no difficulty at 6 months was 71% in the SI joint fusion group and 32% in conservative management group (p=0.0002).
4.6 In the systematic review and meta-analysis of 432 patients, improvements in quality of life (measured on the SF‑36 physical component score [PCS]) were consistent in 2 studies of triangular implants; scores increased from 30.2 and 30.7 at baseline to 42.8 and 37.0 at 6 months respectively. In the RCT of 148 patients, in the SI joint fusion group (n=102), quality of life (measured with an EQ‑5D time trade‑off index utility of current health) improved from 0.44 at baseline to 0.72 at 6‑month follow-up (p<0.001), 0.74 at 12‑month follow-up (p<0.001) and 0.72 at the 24‑month follow-up (p<0.001). The mean change was only 0.05 points in the NSM group at 6 months (p=0.17). For patients who crossed over (n=35), the change was small at 6 months (0.02; p=0.66) but, after crossover, improved from 0.47 at 6 months to 0.73 at 12 months (0.26 point increase, p<0.001). In those who did not cross over (n=11), the change from 6 months to 12 months was small (p=0.008). Quality of life (measured using SF‑36) showed that mean 6‑month changes in PCS and mental health component summary scores (MCS) were statistically significant (p<0.001) in the fusion group compared with the NSM group. Patients who crossed over from NSM after 6 months had larger improvements in PCS and MCS scores compared with those who did not cross over.
4.7 In the systematic review of SI joint fusion of 430 patients, clinical and patient satisfaction with surgery (determined by subjective questionnaires and judged by patients' stated satisfaction with surgery) ranged from 56% to 100% in 299 patients (from 9 studies) who had minimally invasive SI joint fusion, at a mean follow-up of 21 months. In the RCT of 103 patients, satisfaction levels were higher at 3 and 6 months in the SI joint fusion group compared with the conservative management group (p<0.0001 by proportional odds logistic regression). The proportion of patients reporting that they would have the procedure again was also higher in the SI joint fusion group (p=0.0001).
4.8 The specialist advisers listed key efficacy outcomes as improvement in pain and function, and reduced length of hospital stay.
4.9 Eight commentaries from patients who had experience of this procedure were received, which were discussed by the committee.