Risk Factors Affecting Cage Retropulsion into the Spinal Canal Following Posterior Lumbar Interbody Fusion: Association with Diffuse Idiopathic Skeletal Hyperostosis

Risk factors influencing cage retropulsion following lumbar interbody fusion in treating degenerative lumbar diseases: A comprehensive systematic review and meta-analysis

BACKGROUND

Degenerative lumbar diseases (DLDs) often have significant impacts on patients' quality of life, particularly when cage retropulsion (CR) occurs following lumbar interbody fusion (LIF). In this study, we conducted a meta-analysis to assess the risk factors associated with CR after LIF.

METHODS

We retrieved literatures analyzing the risk factors associated with CR following LIF from seven databases. We examined baseline characteristics, diagnosis, comorbidity, fusion level, surgical status, imaging assessment, and cage status to identify potential risk factors.

RESULTS

Sixteen studies involving 8059 patients (251 in the CR group and 7808 in the Non-CR group) were included in the final analysis. The incidence of CR was 3.15 %. Results revealed that older age (mean difference [MD]: 2.35 [0.44, 4.26]), more fusion levels (MD: 0.64 [0.03, 1.25]), comorbidity-osteoarthritis (risk ratio [RR]: 2.02 [1.37, 2.98]), comorbidity-heart disease (RR: 2.95 [1.21, 7.21]), comorbidity-existing vertebral fracture (RR: 5.12 [2.52, 10.39]), endplate injury (RR: 2.93 [1.71, 5.02]), screw loosening (RR: 6.03 [1.90, 19.12]), pear-shaped disc (PSD, RR: 3.14 [1.46, 6.74]), greater mean disc height (MDH, MD: 1.65 [0.58, 2.72]), larger cobb angle (MD: 0.68 [0.10, 1.27] degrees), larger cage height (MD: 0.31 [0.01, 0.61]), and cage type-carbon (RR: 1.62 [1.16, 2.27]) were identified as risk factors for CR following LIF. The incidence of CR decreased with an increase in fusion level.

CONCLUSIONS

Older age, endplate injury, PSD, and nine other factors are identified as risk factors for CR following LIF. Patients with these factors should undergo close monitoring during follow-up to prevent serious complications, such as significant cage displacement.

Current Trends in Artificial Intelligence-Assisted Spine Surgery: A Systematic Review

This systematic review summarizes existing evidence and outlines the benefits of artificial intelligence-assisted spine surgery. The popularity of artificial intelligence has grown significantly, demonstrating its benefits in computer-assisted surgery and advancements in spinal treatment. This study adhered to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses), a set of reporting guidelines specifically designed for systematic reviews and meta-analyses. The search strategy used Medical Subject Headings (MeSH) terms, including "MeSH (Artificial intelligence)," "Spine" AND "Spinal" filters, in the last 10 years, and English- from January 1, 2013, to October 31, 2023. In total, 442 articles fulfilled the first screening criteria. A detailed analysis of those articles identified 220 that matched the criteria, of which 11 were considered appropriate for this analysis after applying the complete inclusion and exclusion criteria. In total, 11 studies met the eligibility criteria. Analysis of these studies revealed the types of artificial intelligence-assisted spine surgery. No evidence suggests the superiority of assisted spine surgery with or without artificial intelligence in terms of outcomes. In terms of feasibility, accuracy, safety, and facilitating lower patient radiation exposure compared with standard fluoroscopic guidance, artificial intelligence-assisted spine surgery produced satisfactory and superior outcomes. The incorporation of artificial intelligence with augmented and virtual reality appears promising, with the potential to enhance surgeon proficiency and overall surgical safety.

The Effect of Posterior Lumbar Interbody Fusion in Lumbar Spine Stenosis with Diffuse Idiopathic Skeletal Hyperostosis: A Finite Element Analysis

OBJECTIVE

Lumbar spinal canal stenosis (LSS) with diffuse idiopathic skeletal hyperostosis (DISH) can require revision surgery because of the intervertebral instability after decompression. However, there is a lack of mechanical analyses for decompression procedures for LSS with DISH.

METHODS

This study used a validated, three-dimensional finite element model of an L1-L5 lumbar spine, L1-L4 DISH, pelvis, and femurs to compare the biomechanical parameters (range of motion [ROM], intervertebral disc, hip joint, and instrumentation stresses) with an L5-sacrum (L5-S) and L4-S posterior lumbar interbody fusion (PLIF). A pure moment with a compressive follower load was applied to these models.

RESULTS

ROM of L5-S and L4-S PLIF models decreased by more than 50% at L4-L5, respectively, and decreased by more than 15% at L1-S compared with the DISH model in all motions. The L4-L5 nucleus stress of the L5-S PLIF increased by more than 14% compared with the DISH model. In all motions, the hip stress of DISH, L5-S, and L4-S PLIF had very small differences. The sacroiliac joint stress of L5-S and L4-S PLIF models decreased by more than 15% compared with the DISH model. The stress values of the screws and rods in the L4-S PLIF model was higher than in the L5-S PLIF model.

CONCLUSIONS

The concentration of stress because of DISH may influence adjacent segment disease on the nonunited segment of PLIF. A shorter-level lumbar interbody fixation is recommended to preserve ROM; however, it should be used with caution because it could provoke adjacent segment disease.

Factors Affecting Incomplete L5/S Posterior Lumbar Interbody Fusion, Including Spinopelvic Sagittal Parameters

Study Design

Retrospective observational study.

Purpose

In this study we identify risk factors, including patient demographics, sagittal parameters, and clinical examinations, affecting incomplete L5/S posterior lumbar interbody fusion (PLIF).

Overview of Literature

The lumbosacral spine is considered to have an interbody fusion rate lower than that of the lumbar spine, but few studies have investigated the cause, including investigating the pelvis. We believe that pelvic morphology can affect L5/S interbody fusion of the lumbosacral spine.

Methods

We observed 141 patients (61 men, 80 women; average age, 65.8 years) who had undergone PLIF and checked for the presence of L5/S interbody fusion. We investigated factors such as age, gender, the presence of diffuse idiopathic skeletal hyperostosis (DISH), fusion level, and grade 2 osteotomy, as well as pre-, post-, and post-preoperative L5/S disk height and angle, lumbar lordosis, Visual Analog Scale (VAS) score, Japanese Orthopaedic Association (JOA) score, and pelvic incidence (PI), comparing those with and without L5/S interbody fusion. In addition, we analyzed the patients classified into short-level (n=111) and multi-level fusion groups (n=30).

Results

Overall, the L5/S interbody fusion rate was 70% (short-level, 78%; multi-level, 40%). Age and pre- and post-preoperative L5/S disk angle were significantly different in each fusion level group. DISH presence, grade 2 osteotomy, and postoperative VAS and JOA scores were significantly different in the short-level fusion group, whereas PI was significantly different in the multi-level fusion group.

Conclusions

Incomplete union after L5/S PLIF correlates with advanced age, many fusion levels, and a large value of preoperative and a small value of post-preoperative L5/S disk angles.