Evaluation of iliac screw, S2 alar-iliac screw and laterally placed triangular titanium implants for sacropelvic fixation in combination with posterior lumbar instrumentation: a finite element study
verfasst von:
Gloria Casaroli, Fabio Galbusera, Ruchi Chande, Derek Lindsey, Ali Mesiwala, Scott Yerby, Marco Brayda-Bruno
This study aimed to implement laterally placed triangular titanium implants as a technique of sacropelvic fixation in long posterior lumbar instrumentation and to characterize the effects of iliac screws, S2 alar-iliac screws and of triangular implants on rod and S1 pedicle screw stresses.
Methods
Four female models of the lumbopelvic spine were created. For each of them, five finite element models replicating the following configurations were generated: intact, posterior fixation with pedicle screws to S1 (PED), with PED and iliac screws (IL), with PED and S2 alar-iliac (S2AI) screws, and with PED and bilateral triangular titanium implants (SI). Simulations were conducted in compression, flexion–extension, lateral bending and axial rotation. Rod stresses in the L5-S1 segment as well as in the S1 pedicle screws were compared.
Results
One anatomical model was not simulated due to dysmorphia of the sacroiliac joints. PED resulted in the highest implant stresses. Values up to 337 MPa in lateral bending were noted, which were more than double than the other configurations. When compared with IL, S2AI and SI resulted in lower stresses in both screws and rods (on average 33% and 41% for S2AI and 17% and 50% for SI).
Conclusions
Implant stresses after S2AI and SI fixations were lower than those attributable to IL. Therefore, pedicle screws and rods may have a lower risk of mechanical failure when coupled with sacropelvic fixation via S2AI or triangular titanium implants, although the risk of clinical loosening remains an area of further investigation.
Graphical abstract
These slides can be retrieved under Electronic Supplementary Material.
×
Anzeige
Bitte loggen Sie sich ein, um Zugang zu diesem Inhalt zu erhalten
Evaluation of iliac screw, S2 alar-iliac screw and laterally placed triangular titanium implants for sacropelvic fixation in combination with posterior lumbar instrumentation: a finite element study
verfasst von
Gloria Casaroli Fabio Galbusera Ruchi Chande Derek Lindsey Ali Mesiwala Scott Yerby Marco Brayda-Bruno
Ob bei einer Notfalloperation nach Schenkelhalsfraktur eine Hemiarthroplastik oder eine totale Endoprothese (TEP) eingebaut wird, sollte nicht allein vom Alter der Patientinnen und Patienten abhängen. Auch über 90-Jährige können von der TEP profitieren.
Beginnen ältere Männer im Pflegeheim eine Antihypertensiva-Therapie, dann ist die Frakturrate in den folgenden 30 Tagen mehr als verdoppelt. Besonders häufig stürzen Demenzkranke und Männer, die erstmals Blutdrucksenker nehmen. Dafür spricht eine Analyse unter US-Veteranen.
Personen mit chronischen Rückenschmerzen, die von einfühlsamen Ärzten und Ärztinnen betreut werden, berichten über weniger Beschwerden und eine bessere Lebensqualität.
Update Orthopädie und Unfallchirurgie
Bestellen Sie unseren Fach-Newsletter und bleiben Sie gut informiert.