Optimization of Three-Level Cervical Hybrid Surgery to Prevent Adjacent Segment Disease: A Finite Element Study

Abstract

Hybrid surgery (HS) allows surgeons to tailor fusion and arthroplasty in the treatment of multiple-level cervical disc degeneration. However, the decision making of selecting either ACDF or ADR for each level in three-level HS remains controversial and has not been fully investigated. This study was aimed to optimize three-level cervical hybrid constructs by systematically investigating their biomechanical properties and their effect on adjacent levels. A finite element model of cervical spine (C2-C7) was developed, and eight C3-C6 surgical models including six HS were constructed. The range of motion (ROM) in flexion, extension, lateral bending, and axial rotation under 2.0 Nm moments with 30 N follower load were simulated. The von Mises stress, strain energy at the adjacent intervertebral disc (IVD) and force at the adjacent facet were calculated. The ROM of the hybrid constructs and adjacent levels was close to that of the intact spine. HS with arthroplasty performed at C5-6 had better performance in terms of ROM reduction at the inferior adjacent level (C6-7). Moreover, C-D-D and 3ADR had best performance in reducing the von Mises stress and strain energy at C6-7. All HS reduced the facet burden at both C2-3 and C6-7 levels. However, the major drawback of HS revealed here is that the effect of C6-7 protection is at the cost of increased C2-3 IVD burden. In conclusion, we recommend C-D-D and 3ADR for patient with C3-C6 disc degeneration without predisposing C2-3 condition. C-C-D could be a good alternative with a lower medical cost. This analysis guides the decision making in three-level cervical HS before future cadaver studies or human clinical trials.

Clinical Outcomes of Cervical Hybrid Reconstructions: A Prospective Study

“…The effect of the arthroplasty level and construct type was unclear, with no significant difference in outcomes noted between the combinations. 36 However, this likely reflects the low numbers in the different treatment groups. As noted, the most common construct was a 3-level cervical hybrid, with a 1-level CTDR cranially, and ACDF at the 2 caudal levels.…”

“…Motion preservation allows load sharing, which provides a more favorable biomechanical environment at adjacent segments compared with that afforded by fusion surgery, thereby reducing the compensatory hypermobility and peak stresses that would otherwise accelerate the processes of RASP and CASP. [33][34][35][36][37][38][39][40] Currently, there are only limited reported studies on cervical hybrid surgery that tend to be short-term studies of small patient cohorts. 41,42 The existing reports, and subsequent systemic reviews synthesizing those reports, demonstrate cervical hybrid surgery to have equivalent outcomes and functional recovery compared with multilevel ACDF, superior range of motion, and favorable improvements in Neck Disability Index (NDI).…”

Comparative Analysis of the Biomechanical Characteristics After Different Minimally Invasive Surgeries for Cervical Spondylopathy: A Finite Element Analysis

“…The contact method between facet cartilages was modeled as frictional contact, with the surface-to-surface method. Additionally, the friction coefficient was 0.1 ( Wong et al, 2020 ; Wo et al, 2021 ). The contact between UJs and cortical bone was identical to facet cartilages.…”

Biomechanical Evaluation and the Assisted 3D Printed Model in the Patient-Specific Preoperative Planning for Thoracic Spinal Tuberculosis: A Finite Element Analysis

“…Finite element analysis (FEA) has been widely used to evaluate the biomechanical effect of surgeries ( Ottardi et al, 2016 ; Wang B. et al, 2019 ; Wong et al, 2020 ). FEA can also facilitate the biomechanical assessment of spinal disease, such as degeneration, compression fracture, and scoliosis ( Natarajan and Andersson, 2017 ; Dupuis et al, 2018 ; Nakashima et al, 2018 ).…”

“…In addition, the range of motion (ROM), intradiscal pressure (IDP), facet joint stress, and internal fixation device stress were calculated and analyzed to evaluate the biomechanical effect of different surgical approaches. Several previous studies indicated that FEA enabled the evaluation of the ROM and IDP of the adjacent segments to predict the risk factors of adjacent segment degeneration after cervical or lumbar surgeries ( Ke et al, 2019 ; Wang B. et al, 2019 ; Hua et al, 2020 ; Wong et al, 2020 ). However, the studies only focused on the postoperative effect of internal fixation to evaluate the biomechanical advantages and disadvantages of surgical treatment.…”