Introduction: While previous studies have described the effects of teriparatide, sublaminar tethering, and spinal process tethering, there is still no widely accepted strategy for reducing PJK risk. This study evaluates the effectiveness of combining sublaminar tethering with shorter UIV screws in minimizing PJK incidence.

Materials and Methods: 161 patients who underwent spinal fusion from the sacrum to the lower thoracic spine for ASD and were followed more than two years were included. PJK was defined as the angle between the lower margin of the upper fixed vertebra and the head of the two vertebrae. Proximal junctional failure was defined as PJK requiring revision surgery. Patients were categorized into three groups: conventional pedicle screw (PS), PS with sublaminar tethering at UIV+1 (T-PS), and shorter PS with sublaminar tethering at UIV+1 (T-SPS). Demographic data, surgical factors, and pre- and postoperative radiographic parameters were analyzed. Statistical significance was set at P<0.05.

Results: PJK occurred in 78 patients (48.9%), with 35 (43.2%) in the PS group, 7 (26.9%) in the T-PS group, and 36 (16.7%) in the T-SPS group. PJK was significantly lower in the T-PS group compared to the PS group (p=0.01). PJF occurred in 6 patients (8.6%) in the PS group, 2 (7.4%) in the T+PS group, and 1 (2.8%) in the T+SPS group, with no significant difference between the groups (p=0.38). Age (p=0.18), BMI (p=0.23), bone mineral density (p=0.07), operative time (p=0.89), fusion level (p=0.38), and pre- and postoperative sagittal parameters were not significantly different among the three groups.

Conclusion Sublaminar tethering is effective in reducing PJK incidence in ASD. Furthermore, the use of a 1-1.5 cm shorter screw at UIV provides additional protection against PJK by allowing a more gradual transition at the fixation site and minimizing vertebral body damage during pedicle screw insertion. This combined approach offers a promising strategy for improving long-term surgical outcomes in ASD patients.