Single position lateral decubitus anterior lumbar interbody fusion (ALIF) and posterior fusion reduces complications and improves perioperative outcomes compared with traditional anterior-posterior lumbar fusion.

BACKGROUND CONTEXT: Lateral decubitus single position anterior-posterior (AP) fusion utilizing anterior lumbar interbody fusion and percutaneous posterior fixation is a novel, minimally invasive surgical technique. Single position lumbar surgery (SPLS) with anterior lumbar interbody fusion (ALIF) or lateral lumbar interbody fusion (LLIF) has been shown to be a safe, effective technique. This study directly compares perioperative outcomes of SPLS with lateral ALIF vs. traditional supine ALIF with repositioning (FLIP) for degenerative pathologies. PURPOSE: To determine if SPLS with lateral ALIF improves perioperative outcomes compared to FLIP with supine ALIF. STUDY DESIGN/SETTING: Multicenter retrospective cohort study. PATIENT SAMPLE: Patients undergoing primary AP fusions with ALIF at 5 institutions from 2015 to 2020. OUTCOME MEASURES: Levels fused, inclusion of L4-L5, L5-S1, radiation dosage, operative time, estimated blood loss (EBL), length of stay (LOS), perioperative complications. Radiographic analysis included lumbar lordosis (LL), pelvic incidence (PI), and PI-LL mismatch. METHODS: Retrospective analysis of primary ALIFs with bilateral percutaneous pedicle screw fixation between L4-S1 over 5 years at 5 institutions. Patients were grouped as FLIP or SPLS. Demographic, procedural, perioperative, and radiographic outcome measures were compared using independent samples t-tests and chi-squared analyses with significance set at p <.05. Cohorts were propensity-matched for demographic or procedural differences. RESULTS: A total of 321 patients were included; 124 SPS and 197 Flip patients. Propensity-matching yielded 248 patients: 124 SPLS and 124 FLIP. The SPLS cohort demonstrated significantly reduced operative time (132.95±77.45 vs. 261.79±91.65 min; p <0.001), EBL (120.44±217.08 vs. 224.29±243.99 mL; p <.001), LOS (2.07±1.26 vs. 3.47±1.40 days; p <.001), and rate of perioperative ileus (0.00% vs. 6.45%; p =.005). Radiation dose (39.79±31.66 vs. 37.54±35.85 mGy; p =.719) and perioperative complications including vascular injury (1.61% vs. 1.61%; p =.000), retrograde ejaculation (0.00% vs. 0.81%, p =.328), abdominal wall (0.81% vs. 2.42%; p =.338), neuropraxia (1.61% vs. 0.81%; p =.532), persistent motor deficit (0.00% vs. 1.61%; p =.166), wound complications (1.61% vs. 1.61%; p =.000), or VTE (0.81% vs. 0.81%; p =.972) were similar. No difference was seen in 90-day return to OR. Similar results were noted in sub-analyses of single-level L4-L5 or L5-S1 fusions. On radiographic analysis, the SPLS cohort had greater changes in LL (4.23±11.14 vs. 0.43±8.07 deg; p =.005) and PI-LL mismatch (-4.78±8.77 vs. -0.39±7.51 deg; p =.002). CONCLUSIONS: Single position lateral ALIF with percutaneous posterior fixation improves operative time, EBL, LOS, rate of ileus, and maintains safety compared to supine ALIF with prone percutaneous pedicle screws between L4-S1.

In situ quantification of experimental ice accretion on tree crowns using terrestrial laser scanning.

In the eastern hardwood forests of North America ice storms are an important disturbance event. Ice storms strongly influence community dynamics as well as urban infrastructure via catastrophic branch failure; further, the severity and frequency of ice storms are likely to increase with climate change. However, despite a long-standing interest into the effects of freezing rain on forests, the process of ice accretion and thus ice loading on branches remains poorly understood. This is because a number of challenges have prevented in situ measurements of ice on branches, including: 1) accessing and measuring branches in tall canopies, 2) limitations to travel during and immediately after events, and 3) the unpredictability of ice storms. Here, utilizing a novel combination of outdoor experimental icing, manual measurements and terrestrial laser scanning (TLS), we perform the first in situ measurements of ice accretion on branches at differing heights in a tree crown and with increasing duration of exposure. We found that TLS can reproduce both branch and iced branch diameters with high fidelity, but some TLS instruments do not detect ice. Contrary to the expectations of ice accretion models, radial accretion varied sharply within tree crowns. Initially, radial ice accretion was similar throughout the crown, but after 6.5 hours of irrigation (second scanning) radial ice accretion was much greater on upper branches than on lower (∼factor of 3). The slope of the change in radial ice accretion along branches increased with duration of exposure and was significantly greater at the second scanning compared to the first. We conclude that outdoor icing experiments coupled with the use of TLS provide a robust basis for evaluation of models of ice accretion and breakage in tree crowns, facilitating estimation of the limiting breaking stress of branches by accurate measurements of ice loads.