Midline lumbar fusion using cortical bone trajectory screws for elderly patients

Background: Midline lumbar fusion (MIDLF) using cortical bone trajectory (CBT) is an alternative method of lumbar spinal fusion. It is useful for reduction not only for approach-related morbidity but also for osteoporosis. This study aimed to present our experience with MIDLF, and focused on survey of postoperative wound pain intensity and outcome assessment. Methods: We retrospectively collected patients who met criteria of elderly (age more than 65 years old), spondylolisthesis, disc herniation, or spinal stenosis, and those who received MIDLF operation. By reviewing medical records, we analysed pain scores, complication rates, and screws loosening. Results: Between January 2016 and June 2017, 23 patients were enrolled. One patient had screw malposition who needed reoperation. The rest patients showed significant improvement of the leading symptom. The visual analogue scale (VAS) scores for wound pain on the first postoperative day, second postoperative day, and before discharge were 3.4, 2.3, and 1.4, respectively. Early ambulation was achieved owing to the mild postoperative pain. The mean VAS scores for lower back and leg pain improvement were 4.7 and 4.5 respectively in the 3-month follow-up. At the most recent follow-up, all the patients reported maintenance of the satisfactory result. No screw-loosening or other complications were noted. Conclusions: In our experience, MIDLF using CBT route seemed to reduce post-op wound pain significantly, so that elderly patients could ambulate earlier. It also had less screws loosening, especially for elderly or osteoporotic patients.