Biomechanical Comparison and Three-Dimensional Analysis of Cement Distribution Patterns for Different Pedicle Screw Designs

Abstract

The purpose of this study to explore strategies for reducing cement leakage during cement-augmented pedicle screw fixation, we compared the cement distribution patterns and biomechanical strengths of different types of cement-augmented fenestrated screws and traditional cement-augmented techniques. We compared five screw groups in this study: (1) Cannulated screws (Cann); (2) distal one-hole screws (D1); (3) distal two-hole screws (D2); (4) middle two-hole screws (M2); and (5) traditional screws with a traditional cement injection technique (Trad). The screws were inserted into cancellous bone blocks using a controlled, adequate cement injection pressure (1.6–2.0 kg), and an appropriate cement viscosity. Center to screw tip distance, three-dimensional distribution, and pull-out strength for cement were compared between groups. The average distance between the cement center and the screw tip was highest in the M2 group, suggesting a higher risk of cement leakage into the spinal canal. The Trad group had the highest migration distance in the z-axis, also reflecting a higher risk of leakage into the spinal canal. The D1 group had the highest pull-out strength ( 253 ± 48.82 N and 797 ± 58.31 N ) in bone blocks representing different degrees of osteoporosis, and the D2 group had the second highest pull-out strength in the severe osteoporosis model. Overall, D1 screws appeared to be the best option for optimizing biomechanical function and minimizing the risk of cement leakage into the spinal canal in patients with osteoporotic bone undergoing spinal surgery.

The Clinical Use of Osteobiologic and Metallic Biomaterials in Orthopedic Surgery: The Present and the Future

“…When PMMA is used as a cement to secure prostheses to the bone, bone adhesion is ensured by including HA particles in the polymer, resulting in a uniform load transmission from the implant to the bone [ 71 , 72 ]. For fragility fractures, such as in vertebroplasty or kyphoplasty, PMMA injections provide increased stability and decreased pain [ 73 , 74 , 75 ]. The extravasation of PMMA to the spinal canal and foramen is a major potential problem that may affect the spinal nerve root [ 74 ].…”

“…Recently, various bone cement cannulated fenestrated screws for osteoporosis patients have been developed. For example, The Iliad™ pedicle screw system (Medyssey Co., Ltd., Jecheon, Republic of Korea), which is a cannulated fenestrated screw system, underwent a study regarding the optimal design of cement-augmented screws to reduce cement leakage-related complications ( Figure 2 ) [ 73 ]. The modified design of the fenestrated screw and the application of the suggested cement injection pressure resulted in minimal spinal canal leakage and easy access.…”

“…The advent of 3D-printed materials, such as pedicle screws or interbody cages, has allowed for easier surgical treatments. When using 3D-printed materials, the incidence of complications, such as cement leakage, was also reduced among patients who previously experienced surgical difficulties ( Figure 3 ) [ 73 , 140 ]. The shape and height of interbody cages are important for correcting the sagittal alignment in degenerative spine diseases, including in osteoporotic patients [ 141 ].…”

Cardiopulmonary Cement Embolism Following Cement-Augmented Pedicle Screw Fixation: A Narrative Review

“…Over the past few decades, several techniques to increase the anchoring strength of pedicle screws and reduce the risk of screw loosening have been developed, with cement-augmented pedicle screws (CAPS) being the most promising and beginning to be widely used. The use of CAPS in patients with osteoporosis strengthens screw fixation, decreases the incidence of screw loosening, and improves the fusion rate [ 2 , 3 ], thereby possibly reducing the extent of spinal fusion and directly contributing to minimizing surgical invasiveness; therefore, CAPS is consistent with the concept of minimally invasive spinal treatment.…”

“…However, while CAPS is being increasingly used, post-CAPS cement leakage is a considerable problem. Cement leakage into the spinal canal can cause spinal cord compression symptoms, including neurologic deficits and pain, while leakage into the epidural vein, vena cava, right atrium, pulmonary artery, or multiple lung arterioles can cause cardiac or pulmonary cement embolism (PCE) [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. Since both embolisms have the same pathology, this study included cardiopulmonary cement embolisms after CAPS as CPCE.…”