Biomechanical comparison of different interspinous process devices in the treatment of lumbar spinal stenosis: a finite element analysis

Abstract

Background Lumbar spinal stenosis (LSS) is a common disease among elderly individuals, and surgery is an effective treatment. The development of minimally invasive surgical techniques, such as the lumbar interspinous process device (IPD), has provided patients with more surgical options. Objective To investigate the biomechanical properties of different IPDs, including BacFuse, X-Stop and Coflex, in the treatment of LSS. Methods Based on the computed tomography images of a patient with LSS, four finite element (FE) models of L3-S5 were created in this study. The FE models included a surgical model of the intact lumbar spine and surgical models of the lumbar IPDs BacFuse, X-Stop, and Coflex. After validating the models, they were simulated for four physiological motions: flexion, extension, lateral bending and axial rotation, and range of motion (ROM). Stress distribution of discs and facet joints in each segment, stress distribution of the spinous process in the operated section, and stress distribution of the internal fixation were compared and analysed. Results Compared to the model of the intact lumbar spine, the other three models showed a decrease in ROM and disc and facet joint stresses in the surgical segment during movement and an increase in ROM and disc and facet joint stresses in the adjacent segments. These effects were greater for the proximal adjacent segment with BacFuse and more pronounced for the distal adjacent segment with Coflex, while X-Stop had the greatest stress effect on the spinous process in the surgical segment. Conclusion BacFuse, Coflex and X-Stop could all be implemented to effectively reduce extension and disc and facet joint stresses, but they also increase the ROM and disc and facet joint stresses in adjacent segments, which may cause degeneration.

Perspective: Efficacy and outcomes for different lumbar interspinous devices (ISD) vs. open surgery to treat lumbar spinal stenosis (LSS)

“…Five biomechanical studies using surgical fusion models documented the efficacy of different ISD devices in reducing ROM at the index and adjacent surgical levels [Tables 1 and 2]. [1,4,5,10,12] In 6 human cadavers, Hirsch et al…”

“…In the same year, Liu et al (2022) performed a biomechanical analysis in flexion, extension, lateral bending/axial rotation, and ROM with CT images of LSS utilizing four finite element (FE) models from L3-S5 (i.e., including the intact lumbar spine, and BacFuse, X-Stop and Coflex ISD devices); although all 3 ISD decreased ROM in extension, the BacFuse ISD further increased cephalad stress, the Coflex ISD increased distal stress, and the X-STOP ISD placed maximal stress at the index/surgical levels. [10] Table 2: List of interspinous and interlaminar stabilization and distraction devices.…”

“…Five biomechanical studies using surgical fusion models documented the efficacy of different ISD devices in reducing ROM at the index and adjacent surgical levels [ Tables 1 and 2 ]. [ 1 , 4 , 5 , 10 , 12 ] In 6 human cadavers, Hirsch et al . (2015) evaluated foraminal surface areas in flexion/extension (i.e., using a spinal loading frame, testing flexion/extension from 0-10 Nm, marking L34, L45, and L5S1 foramina, employing Stereoscopic 3D images before/after implants) placed in In-space, X-STOP, DIAM, and Wallis ISD at L45; “All four devices significantly opened the L45 foramen in extension”, but for the X-Stop(®) and In-space(®) devices the;“... L4-L5 foramen opened not only in extension but also in flexion and the neutral position.”[ 5 ] Using six human male cadaver biomechanical models, Che et al .…”

“…For treating lumbar spinal stenosis, we compared the efficacy and outcomes of 3 different categories of interspinous devices (ISD) vs. open surgery (i.e., laminectomy/decompression, posterior lumbar interbody fusion (PLIF), posterolateral fusion (PLF/other) [Tables 1 and 2]. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] e three categories Trautwein [14] The Spine J 2010 of ISD included; the original (i.e., Wallis), current (i.e., X-STOP, Wallis, DIAM, Aperius PercLID), and new generation (i.e., Coflex, Superion Helifix, In-Space) ISD. Biomechanically, ISD devices were designed to; "off-load" the pressure on the disc space, increase intervertebral foraminal/disc space height, reversed/preserve the lumbar lordosis, limit range of motion (ROM)/stabilize the index surgical level, and decrease the incidence of adjacent segment disease (ASD).…”

Comparative Effects and Safety of Full-Endoscopic Versus Microscopic Spinal Decompression for Lumbar Spinal Stenosis: A Meta-Analysis and Statistical Power Analysis of 6 Randomized Controlled Trials

“…Lumbar spinal stenosis is described as pathological spinal canal narrowing [ 1 ], which will result in a series of neurological symptoms due to subsequent compression of nerve roots, including back and leg pain, claudication, and walking difficulty [ 2 , 3 ]. As one of the most prevalent degenerative conditions [ 4 - 6 ], lumbar spinal stenosis was associated with an increased social and economic burden because it leads to pain and disability and reduces patients’ quality of life [ 7 ].…”