In Vitro Biomechanical Evaluation of a Novel, Minimally Invasive, Sacroiliac Joint Fixation Device

Abstract

Background: Sacroiliac (SI) joint pathology may result in low-back pain, which causes substantial disability. Treatment failure with operative management of SI pain may be related to incomplete fusion of the joint and to fixation failure. The objective of this study was to evaluate the initial biomechanical stability of SI joint fixation with a novel implantable device in an in vitro human cadaveric model. Methods: The right and left sides of 3 cadaveric L4-pelvis specimens were tested (1) intact, (2) destabilized, and (3) instrumented with an implantable SI joint fixation device using a simulated single-stance load condition. Right-leg and left-leg stance data were grouped together for a sample size of 6, and angular range of motion (ROM) was determined during application of flexion-extension, lateral bending, and axial rotation bending moments to a limit of 7.5 Nm. Results: Following intact testing, destabilization by severing the posterior SI joint capsule and ligaments and the pubic symphysis reliably produced a significantly destabilized joint with the mean angular ROM more than doubling in flexion-extension and lateral bending and more than tripling in axial rotation (P .003) compared to the intact condition. Instrumentation with the SI screw fixation device significantly reduced mean joint ROM compared to the destabilized condition in all 3 anatomic planes tested (P , .001). When compared to the intact condition, the SIinstrumented condition significantly reduced lateral bending (P ¼ .01) and had a similar ROM in flexion-extension (P ¼ .14) and axial rotation (P ¼ .85). Conclusions: Instrumentation with the SI screw fixation device significantly reduced mean joint ROM compared to the destabilized condition, with similar ROM in flexion-extension and axial rotation, and it significantly reduced ROM in lateral bending compared to that for the intact joint. The ROM values observed with the instrumented condition were comparable to levels of mobility considered favorable for spinal fusion.

Effects of Manipulations of Oblique Pulling on the Biomechanics of the Sacroiliac Joint: A Cadaver Study

“…In this study, after sacroiliac screw xation, the rotation angle of SIJ reduced by 48%, and the displacement of SIJ reduced by 57%. It could be seen that the ROM of SIJ signi cantly reduced, which was consistent with the previous studies 29,30 . The results suggested that sacroiliac screw xation was an effective method for SIJ xation.…”

“…In an in vitro study on seven human specimens, they found a reduction of the ROM of 41%, 36% and 36% in exion-extension, lateral bending and axial rotation, respectively. Cross et al 29 argued that under the torque of exion-extension, lateral exion, rotation, the rotation angles of SIJ were 2.92° and 1.75°, 1.16°a nd 0.59°, 1.46° and 1.52° in the state of intact SIJ and xed SIJ with sacroiliac screw. In this study, after sacroiliac screw xation, the rotation angle of SIJ reduced by 48%, and the displacement of SIJ reduced by 57%.…”

Biomechanics of a laterally placed sacroiliac joint fusion device supplemental to S2 alar-iliac fixation in a long-segment adult spinal deformity construct: a cadaveric study of stability and strain distribution

“…[16][17][18][19][20][21] Previous in vitro biomechanical studies demonstrated that 3 triangular titanium implants placed across the sacroiliac joint significantly reduced range of motion (ROM) compared with that in the intact joint. [22][23][24] Multiple biomechanical studies have demonstrated that using 1 sacroiliac joint screw results in less stability than that achieved with the placement of 2 screws across the joint. [25][26][27][28] The general hypothesis-that increased number of fixation points across the sacroiliac joint improves stability-is corroborated by these studies; however, data are scarce about this effect in long-segment constructs used to address adult spinal deformity.…”

Biomechanical effects of a novel posteriorly placed sacroiliac joint fusion device integrated with traditional lumbopelvic long-construct instrumentation

“…Biomechanically, these implants reduce the SI joint range of motion (ROM) compared with the intact joint. [17][18][19][20][21][22][23][24][25] In a finite element modeling study, Lindsey et al 26 reported that ROM was sequentially reduced as the number of implants placed across the SI joint increased from 1 to 3. More broadly, multiple biomechanical studies have demonstrated that a single SI joint screw results in less stability than two screws across the joint.…”