Purpose: To compare efficacy of ultrasound (US)-guided single-injection nerve blocks (SINB) before bipolar hemiarthroplasty (BHA) of the hip in patients with femoral neck fractures. Materials and Methods: Clinical outcomes of 89 patients who underwent BHA between September 2016 and February 2018 were retrospectively compared. Eight patients were excluded according to exclusion criteria and the remaining patients were divided into two groups: patients who received SINB before surgery (Group I; n=40), and patients who did not (Group II; n=41). The femoral, obturator, and lateral femoral cutaneous nerves were each blocked separately under US guidance. Pain scores determined using the visual analogue scale (VAS) were recorded 6, 12, 24, and 48 hours postoperatively, and all use of analgesics were recorded separately for 72 hours after surgery. Duration of hospitalization, general complications, and local complications due to SINB were also compared among the groups. Results: Significant differences were observed between the two groups: I) VAS at 6 hours and at 12 hours after the operation, II) total amounts of analgesics used. VAS at 24 hours and at 48 hours were not significantly different between the two groups. General complications and duration of hospitalization were also not significantly different between the groups. Conclusion: US-guided lower limb nerve blocks provide excellent immediate postoperative pain relief and can be used as a safe, and effective method of pain control after BHA.

Purpose:To analyze the risk factors for posterior migration of a single cage after transforminal lumbar interbody fusion (TLIF). Materials and Methods: This study was conducted retrospectively on 48 patients (60 discs) who were followed-up for 1 year after TLIF from January 2015 to January 2017. The patients were divided into two groups: group 1 containing 16 patients (17 discs) with cage migration and group 2 containing 32 patients (43 discs) without it. Information related to cage migration, such as the demographic factors, shape of disc, level and location of the cage inserted, and disc height change, was acquired from the medical records and radiologic images, and the possibility for generating posterior migration of cage was evaluated statistically. Results: The demographic factors and cage-inserted level were similar in the two groups (16 patients in group 1, 32 patients in group 2). In the migration group, number of patients with a pear-type disc, 9 patients, was significantly larger; the disc height change, 1.8 mm, was significantly smaller; and the cage was located frequently on non-center in the anteriorposterior view and center in the lateral view in 9 and 15 out of 16 patients, respectively. Conclusion: A pear-type disc shape, small disc height change, cage with non-center on the anteriorposterior view and non-anterior on the lateral view are the risk factors for posterior migration. These factors are important for preventing posterior migration of the cage.