Osseodensification for enhancement of spinal surgical hardware fixation

Abstract

Integration between implant and bone is an essential concept for osseous healing requiring hardware placement. A novel approach to hardware implantation, termed osseodensification, is described here as an effective alternative. 12 sheep averaging 65 kg had fixation devices installed in their C2, C3, and C4 vertebral bodies; each device measured 4 mm diameter×10 mm length. The left-sided vertebral body devices were implanted using regular surgical drilling (R) while the right-sided devices were implanted using osseodensification drilling (OD). The C2 and C4 vertebra provided the t=0 in vivo time point, while the C3 vertebra provided the t=3 and t=6 week time points, in vivo. Structural competence of hardware was measured using biomechanical testing of pullout strength, while the quality and degree of new bone formation and remodeling was assessed via histomorphometry. Pullout strength demonstrated osseodensification drilling to provide superior anchoring when compared to the control group collapsed over time with statistical significance (p < 0.01). On Wilcoxon rank signed test, C2 and C4 specimens demonstrated significance when comparing device pullout (p=0.031) for both, and C3 pullout tests at 3 and 6 weeks collapsed over time had significance as well (p=0.027). Percent bone-to-implant contact (%BIC) analysis as a function of drilling technique demonstrated an OD group with significantly higher values relative to the R group (p < 0.01). Similarly, percent bone-area-fraction-occupancy (BAFO) analysis presented with significantly higher values for the OD group compared to the R group (p=0.024). As a function of time, between 0 and 3 weeks, a decrease in BAFO was observed, a trend that reversed between 3 and 6 weeks, resulting in a BAFO value roughly equivalent to the t=0 percentage, which was attributed to an initial loss of bone fraction due to remodeling, followed by regaining of bone fraction via production of woven bone. Histomorphological data demonstrated autologous bone chips in the OD group with greater frequency relative to the control, which acted as nucleating surfaces promoting new bone formation around the implants, providing superior stability and greater bone density. This alternative approach to a critical component of hardware implantation encourages assessment of current surgical approaches to hardware implantation.

Atemporal osseointegration: Early biomechanical stability through osseodensification

“…Given that removal torque is comparable across all instrumentation groups (CCW, CW, and R), the lack of statistical significance suggests that OD drilling provides primary stability at day of surgery comparable to fully healed, regular drilling implants at three‐weeks. Studie­s employing this additive drilling technique (OD) have already shown increased implant stability and bone area occupancy when compared to conventional drilling techniques; the findings of this work are consistent to this growing body of data …”

“…Surgical fixation of metal implants into bone is an essential component of correcting bone deformities or fractures. This type of intervention is commonly used to rehabilitate patients to baseline function and skeletal integrity . Osseointegration, the direct functional and structural connection between implant and bone, is vital in implant surgery to ensure long‐term implant stability .…”

“…Other examples include geometrical configuration, implant surface characteristics such as texture, composition, or degree of porosity . In addition to the aforementioned geometrical configurations, recent work has indicated that drilling protocols that differ from conventional subtractive drilling methods not only improve implant initial stability but also contributes to faster osseointegration …”

Form and functional repair of long bone using 3D‐printed bioactive scaffolds

“…DW printing, which deposits concentrated colloidal gels, “ink,” controlled by computer‐aided design (CAD)/computer‐aided manufacturing system (Sun & Lal, ), allows for fabrication of constructs without the need for a mold (Miranda, Saiz, Gryn, & Tomsia, ). The controlled extrusion of colloidal pastes, slurries, or inks can “print” structures that are adapted from clinical imaging (e.g., CT scans), allowing for the printing of custom‐fit and fill scaffolds with macrogeometric, mesogeometric, and microgeometric porous dimensions proven to be osseoconductive in other biomaterial studies (Ellingsen, Johansson, Wennerberg, et al, ; Lopez et al, ).…”

A Multicenter Retrospective Clinical Study with Up-to-5-Year Follow-up Utilizing a Method that Enhances Bone Density and Allows for Transcrestal Sinus Augmentation Through Compaction Grafting

“…19 Additionally, the site preparation method may accelerate new bone formation as a product of the residual bone chips that act as a nucleation for new bone formation. [20][21][22] The capacity of the osseous densification drilling process to elevate the sinus floor without sinus membrane perforation is based on the fact that the densifying burs are capable of bone instrumentation in a counterclockwise motion. Hence, irrigation is optimized throughout the osteotomy site, and irrigation solution is constantly present at the apical end of the osteotomy.…”