The Influence of Proximal Anchors on the Risk of Proximal Junctional Fracture in the Osteoporotic Spine

Abstract

The current study failed to observe a significant impact of using transverse process hooks over pedicle screws on top of multilevel pedicle screw construct to decrease the risk of PJF.

Instrumentation techniques to prevent proximal junctional kyphosis and proximal junctional failure in adult spinal deformity correction—a systematic review of biomechanical studies

“…Eight out of twelve studies used cadaveric human specimen whereas the animal specimen was either porcine [21−23] or calf [24]. Three studies performed flexion-compression testing with varying protocols and did not measure ROMs [22,25,26]. The remaining nine studies all measured ROMs, primarily in flexion-extension, of which five studies additionally measured IDP, primarily at the index segment as an approximation of vertebral stresses (Table 2) [21,23,24,27−32].…”

“…Transverse process hooks as semi-rigid junctional fixation at UIV+1 were studied in three different studies (Fig. 1, F) [21,23,26]. Both Fachinello et al and Thawrani et al investigated the use of TPHs in pure bending cadaveric porcine study [21,23].…”

“…Both Fachinello et al and Thawrani et al investigated the use of TPHs in pure bending cadaveric porcine study [21,23]. Mac-Thiong et al compared TPHs at the junctional zone to pedicle screws in a cadaveric human experiment, in which spine segments were subjected to cyclic flexion-compression until failure [26].…”

Biomechanical assessment of proximal junctional semi-rigid fixation in long-segment thoracolumbar constructs

“…6,25 However, the restoration of ideal sagittal balance following long-segment thoracolumbar spinal fusion is associated with increased biomechanical stress at the PJ levels, which is directly implicated in the development of PJK and PJF. 12,15,17 Various global factors (including low BMD, older age, obesity, under-or overcorrection of pelvic or global sagittal alignment, the type/severity of underlying deformity, and underlying neuromuscular pathologies) and local junctional factors (including disruption of the posterior tension band, use of rigid instrumentation, improper end-vertebra selection, and pre-existing proximal level disc degeneration) have been linked to the development of PJK and PJF. 1,9,14,15,17,[27][28][29] These factors likely further influence the abrupt changes in stress across the rigid instrumented and mobile non-fused segments of the spine.…”

“…Multiple hybrid constructs have been proposed to assist in transitional zone widening at the proximal end of long-segment constructs to reduce the strain placed on the adjacent motion segments. 10,12,17,30 Recently, our clinical experience with sublaminar banding at the proximal end of long-segment thoracolumbar spinal fusion constructs to expand the transition zone has been associated with lower rates of PJK and prevention of PJF. 27 However, no comparative biomechanical studies have been undertaken to date to assess the potential advantage of such semi-rigid hybrid designs to mitigate PJ stress.…”