Publications by authors named "A Theologis"
Article Synopsis
- - The study focuses on the biomechanical stabilization of the occipitocervical junction using novel multi-rod constructs to address challenging pathologies that arise due to limited bone surfaces in this area.
- - Researchers evaluated different rod configurations (2-rod TI, 2-rod CoCr, 3-rods, and 4-rods) and used finite element modeling to assess stress and range of motion across the OC-C4 junction.
- - Results indicated that 3- and 4-rod constructs exhibit lower stress on the rods compared to 2-rod constructs, while showing similar functionality regarding range of motion and discal stresses.
Purpose: To assess patients' perceptions of their abdominal wall following extensile anterolateral approaches to the thoracolumbar spine for adult spinal deformity (ASD) using validated questionnaires.
Methods: Adults who underwent anterior-posterior thoracolumbar spinal operations to the pelvis for ASD in which the anterior fusion was performed through an extensile anterolateral approach were reviewed. Three questionnaires were administered at least 1 year following surgery and included The Abdominal Core Health Quality Collaborative Survey (AHS-QC), The Patient Scar Assessment Scale (PSAS), and The Anterior Abdominal Incision Questionnaire (AAIQ).
Effects of pelvic fixation strategies and multi-rod constructs on biomechanics of the proximal junction in long thoracolumbar posterior instrumented fusions: a finite-element analysis.
Spine Deform
November 2024
Purpose: To assess the effect of various pelvic fixation techniques and number of rods on biomechanics of the proximal junction of long thoracolumbar posterior instrumented fusions.
Methods: A validated spinopelvic finite-element (FE) model was instrumented with L5-S1 ALIF and one of the following 9 posterior instrumentation configurations: (A) one traditional iliac screw bilaterally ("2 Iliac/2 Rods"); (B) T10 to S1 ("Sacral Only"); (C) unilateral traditional iliac screw ("1 Iliac/2 Rods"); (D) one traditional iliac screw bilaterally with one midline accessory rod ("2 Iliac/3 rods"); (E) S2AI screws connected directly to the midline rods ("2 S2AI/2 Rods"); and two traditional iliac screws bilaterally with two lateral accessory rods connected to the main rods at varying locations (F1: T10-11, F2: T11-12, F3: T12-L1, F4: L1-2) ("4 Iliac/4 Rods"). Range of motions (ROM) at T10-S1 and T9-T10 were recorded and compared between models.
Background: Pedicle subtraction osteotomy (PSO) is effective for correcting spinal malalignment but is associated with high complication rates. The biomechanical effect of different PSO levels remains unclear, and no finite element (FE) analysis has compared L2-, L3-, L4-, and L5-PSOs.
Purpose: To assess the effects of PSO level on the spine's global range of motion, stresses on posterior instrumentation, load sharing with the anterior column, and proximal junctional stresses.