Methods: This study included 62 patients with Lenke type 2 AIS who underwent posterior correction and fusion surgeries. The patients were categorized into the PSI and non-PSI groups based on their radiographic shoulder height 2 years after surgery. Radiographic parameters, lower end vertebra (LEV), lower instrumented vertebra (LIV), sagittal stable vertebra (SSV), postoperative DA and DJK, and Scoliosis Research Society 22 scores were compared between the two groups using unpaired t -tests or Pearson’s chi-square tests. Results: Twenty-eight patients in the PSI group and 34 in the non-PSI group were evaluated. Three patients had DA in the PSI group and 10 with DA and four with DJK in the non-PSI group. LIV–LEV was higher in the PSI group than in the non-PSI group. Although the LIV–SSV was not significantly different between the two groups, among the three patients with DJK, two had LIV–SSV of −3, one had −1, and one had 0. No significant differences in other examinations were noted between the two groups. Conclusions Although more proximal LIV selection might lead to stable DA and DJK, the LIV selection should not be extended distally to prevent DA and DJK because favorable shoulder balance and clinical outcome can still be achieved.

Methods: For this prospective multicenter study, 40 patients were followed up through radiologic and clinical examinations for at least 1 year postoperatively. All surgical procedures were either single- or double-level LLIF using bioactive porous titanium spacers without bone grafts. Results: Four patients were excluded from the study owing to aggravation from other comorbidities. Another 36 patients, including 26 and 10 with single- and double-level LLIFs, respectively, participated in the follow-up. The mean age at the time of surgery was 63.7 years. The mean operating time was 50.5 minutes per level. The mean estimated intraoperative blood loss was 11.6 mL per level. Clinical scores improved in all cases and were maintained throughout the follow-up period. The intervertebral bony union rates were 67.4% and 84.8% at 6 and 12 months, respectively. Endplate cyst signs were observed in 13.0% and 8.7% of patients at 6 and 12 months, respectively. Fused segmental angles were maintained throughout the follow-up period, indicating no cage subsidence. Conclusions Single- and double-level LLIFs using bioactive porous titanium spacers without bone grafts were found to be minimally invasive, resulting in clinical and imaging results comparable with conventional procedures. Therefore, this type of implant may be an option for minimally invasive spinal fusion surgery.

Retrospective cohort study.

Retrospective cohort study.