Search Results (28)

Background/Objectives: Lateral lumbar interbody fusion (LLIF) has gained popularity as an effective technique for indirect decompression through ligamentotaxis. Despite the perceived importance of using appropriately sized cages for achieving optimal decompression, comprehensive reports on cage size and its impact on indirect decompression are limited. This study aimed to assess the ligamentotaxis effect by measuring the “backward bulging” length in pre- and postoperative MRIs and examining its correlation with cage size and subsidence. Methods: T2 images of 270 patients with lumbar herniated disc and/or lumbar spondylolisthesis (June 2022 to March 2025) were analyzed for 530 intervertebral spaces. Data on gender, age, length of hospital stay, preoperative and postoperative lumbar JOA scores, and the level of the disease were collected. Measurements included backward bulging length, intervertebral height, and cage subsidence. Statistical analysis was performed using StatMate. Surgical procedures involved oblique lateral interbody fusion (OLIF) to minimize impact on the iliopsoas and lumbar plexus. Trial cages starting from 8 mm were sequentially inserted, with confirmation through lateral fluoroscopy. Posterior fixation was performed using percutaneous pedicle screws. Results: Analysis of 530 intervertebral spaces revealed that 70% could accommodate a cage 3 mm or larger than the preoperative intervertebral height. Significant backward bulging shortening (3 mm or more) occurred in 339 spaces, predominantly with larger cages. Only 8.8% of cases (14/159) with a large backward bulging shortening had an intervertebral height extension of 3 mm or less. On the other hand, a large reduction in backward bulging was observed in 91.3% of cases (339/371) with an intervertebral height extension of 3 mm or more. Postoperative cage subsidence was observed in 9.2% (49/530) of all intervertebral spaces and 8.6% (32/371) in spaces where a cage larger than 3 mm was used. There was no statistically significant difference between these two groups. Conclusions: To achieve a sufficient ligamentotaxis effect, it is necessary to select a cage size that allows for an intervertebral height increase of at least 3 mm compared to the preoperative measurement. Full article

Background/Objectives: Lumbar spine surgery has undergone significant technological transformation in recent years, driven by the goals of minimizing invasiveness, improving precision, and enhancing clinical outcomes. Emerging tools—including robotics, augmented reality, computer-assisted navigation, and artificial intelligence—have complemented the evolution of minimally invasive surgical (MIS) approaches, such as endoscopic and lateral interbody fusions. Methods: This systematic review evaluates the literature from February 2020 to February 2025 on technological and procedural innovations in LSS. Eligible studies focused on degenerative lumbar pathologies, advanced surgical technologies, and reported clinical or perioperative outcomes. Randomized controlled trials, comparative studies, meta-analyses, and large case series were included. Results: A total of 32 studies met the inclusion criteria. Robotic-assisted surgery demonstrated high accuracy in pedicle screw placement (~92–94%) and reduced intraoperative blood loss and radiation exposure, although long-term clinical outcomes were comparable to conventional techniques. Intraoperative navigation improved instrumentation precision, while AR enhanced ergonomic workflow and reduced surgeon distraction. AI tools showed promise in surgical planning, guidance, and outcome prediction but lacked definitive evidence of clinical superiority. MIS techniques—including endoscopic discectomy and MIS-TLIF—offered reduced blood loss, shorter hospital stays, and faster recovery, with equivalent pain relief, fusion rates, and complication profiles compared to open procedures. Lateral and oblique approaches (XLIF/OLIF) further optimized alignment and indirect decompression, with favorable perioperative metrics. Conclusions: Recent innovations in lumbar spine surgery have enhanced technical precision and perioperative efficiency without compromising patient outcomes. While short-term benefits are clear, long-term clinical advantages and cost-effectiveness require further investigation. Integration of robotics, navigation, AI, and MIS into spine surgery reflects an ongoing shift toward personalized, data-driven, and less invasive care. Full article

Background/Objectives: Despite recent advances in minimally invasive extrapleural lateral approaches, oblique lateral interbody fusion (OLIF) at the upper lumbar level is often difficult and limited to optimal reconstruction. We aimed to compare the radiological outcomes and approach-related complications of OLIF between the upper (L1–2 or L2–3) and lower (L3–4 or L4–5) levels. Methods: This study is a retrospective review of OLIF in the upper (n = 63) and lower (n = 60) lumbar level groups. Radiological parameters included the anterior/posterior disc height, coronal/sagittal disc angle, cage position, cage subsidence, and fusion rate at a postoperative 1-year follow-up. Approach-related complications including pleural/peritoneal lacerations, neurovascular injury, and other organ injuries were examined. Results: The baseline radiological parameters were similar between the two groups (all p > 0.05). At 1-year postoperatively, the anterior disc height (ADH) was significantly greater in the lower-level group (p = 0.031), while no significant differences were observed in the posterior disc height, coronal/sagittal disc angle, cage anterior position, or cage subsidence rate (all p > 0.05). The fusion rates were 97.9% and 95.0% at the upper and lower lumbar levels, respectively (p = 0.146). During OLIF at the upper lumbar level, chest tube insertion due to pleural laceration was observed in 11 (17.5%) cases. One case (1.2%) of segmental artery injury and two cases (3.2%) of pseudo-hernia were attributed to iliohypogastric nerve injury. Conclusions: Although the extrapleural approach in OLIF at the upper lumbar level is often limited, the radiological outcomes were comparable to those of OLIF at the lower lumbar level. Full article

Background/Objectives: Additional lateral fixation is a method with the potential to redistribute cage loading during oblique lumbar interbody fusion (OLIF). However, its biomechanical effects remain poorly understood. This study aimed to compare the mechanical responses of the lumbar spine following OLIF, both with and without additional lateral fixation, using a finite element (FE) analysis. Methods: An FE lumbar model with an OLIF cage at the L4–L5 levels was developed. A lateral fixation system comprising screws and a rod was incorporated to redistribute the cage loading and enhance spinal stability. Two OLIF cage positions—centered and at an oblique angle—were compared. Results: The additional lateral fixation reduced cage loading by 70% (409 to 123 N) and 72% (411 to 114 N) for the centered and oblique cage positions, respectively. Without lateral fixation, the peak equivalent stress on the cage during extension increased threefold (66 to 198 MPa) for the oblique position compared with that for the centered position. Conclusions: An additional lateral screw–rod fixation system is suggested as a complementary approach to the OLIF technique to mitigate endplate loading and pressure. Full article

Background and Objectives: Spine surgery has undergone significant advancements, particularly with regard to robotic systems that enhance surgical techniques and improve patient outcomes. As these technologies become increasingly integrated into surgical practice, it is essential to evaluate their added value and cost savings. Hence, this study compared robot-assisted and navigation-based spine surgery, focusing on surgical efficiency. Materials and Methods: We conducted a single-center, retrospective cohort study of patients undergoing single- and double-level transforaminal lumbar interbody fusion (TLIF) and oblique lumbar interbody fusion (OLIF) surgeries. Patients were divided into two groups: those who had robot-assisted and navigation-based surgeries, stratified by surgery type (TLIF or OLIF) and fusion levels (one or two). A comparative analysis of factors related to surgical efficiency, including operative duration, blood loss, and length of hospital stay, was conducted. Results: Our results showed a statistically significant reduction in operative duration for robot-assisted one- and two-level OLIF cases, with average time savings of 50 and 62 min, respectively, compared to navigation-based surgery. These time savings translated to an estimated cost reduction of SGD 1500 for the hospital for each patient for a two-level OLIF procedure and could be higher as the number of operated levels increase. Conclusions: These results indicated that robot-assisted spine surgery offers superior surgical efficiency and cost savings, particularly with increased numbers of surgical levels. As robotic technologies evolve, their integration into spine surgery is justified, promising improved patient outcomes and cost-effectiveness. Full article

Background: Oblique lumbar interbody fusion (OLIF) is a minimally invasive technique used to manage degenerative lumbar conditions. The presence of vacuum phenomenon (VP) and associated endplate sclerosis may increase the risk of cage subsidence. This study evaluated the relationship between VP grade, endplate sclerosis, and subsidence in OLIF. Methods: This retrospective cohort study included 165 patients who underwent a single-level OLIF for lumbar stenosis. Patients were stratified into VP grades (0–3) based on preoperative computed tomography scans. Disc height, endplate sclerosis, and cage subsidence were radiologically assessed. Clinical outcomes, including back and leg pain visual analog scale, Oswestry Disability Index, and EuroQol-5 Dimension, were measured preoperatively and at follow-up. Results: High VP grades were associated with low preoperative disc height and increased endplate sclerosis. Although no significant differences in clinical outcomes or final fusion rates across VP grades were observed, the subsidence rate increased with VP grade, with a significant difference between VP grades 1 and 2 (p = 0.045) and between VP grades 2 and 3 (p = 0.032), indicating that subsidence rates increased as the VP grade advanced. Conclusions: High VP grades, particularly grades 2 and 3, may increase the risk of cage subsidence following OLIF. Therefore, VP grading may be worth considering during surgical planning to reduce the subsidence risk and improve outcomes. Full article

Background: This study aimed to evaluate the impact of iliac crest height on clinical and radiological outcomes following oblique lateral interbody fusion (OLIF) at the L4–5 level. Methods: Data of patients who underwent single-level OLIF at the L4–5 level for degenerative spinal stenosis were retrospectively analyzed. The patients were categorized into three groups based on their iliac crest height measured relative to the L4 and L5 pedicles. Categorical and quantitative analyses, including univariate and multivariate logistic regressions, were performed to identify subsidence predictors. Clinical outcomes, including visual analog scale scores for back and leg pain, were assessed over a minimum 2-year follow-up. Results: No significant differences in cage obliquity were observed across the iliac crest height groups (axial angles, p = 0.39; coronal angles, p = 0.79). However, subsidence was significantly more common in patients with higher iliac crest heights, particularly at crest level III, where the subsidence rate reached 43% (p = 0.01). Subsidence was predominantly associated with damage to the L5 endplate, which occurred in 83% of subsidence cases at crest level III. A cutoff value of 12 mm for iliac crest height, above which the risk of subsidence significantly increased, was identified (AUC = 0.688, p = 0.042). Conclusions: Iliac crest height is a critical factor for predicting subsidence following OLIF at the L4–5 level. Surgeons should consider alternative strategies and meticulous preoperative planning in patients with an iliac crest height ≥ 12 mm to reduce the risk of adverse outcomes. Further studies are needed to validate these findings and to explore their long-term implications. Full article

Background/Objectives: Various surgical approaches have been proposed for treating adjacent segment disease (ASD) after lumbar fusion. However, studies using oblique lumbar interbody fusion (OLIF) to treat ASD are lacking. The current study assessed the postoperative outcomes of single-level OLIF for ASD, comparing the results with those for patients undergoing transforaminal lumbar interbody fusion (TLIF). Methods: Patients who underwent single-level OLIF or TLIF for lumbar ASD were retrospectively included. Clinical outcomes, that is, the results of assessments using the Euroqol 5-Dimension quality of life scale (EQ-5D), the Oswestry Disability Index, and the visual analog scale, were evaluated. Radiologic parameters, including disc height (DH), segmental lordosis (SL), segmental coronal angle (SCA), lumbar lordosis, and pelvic incidence–lumbar lordosis mismatch, were also assessed. Results: A total of 65 patients were enrolled: 32 in the OLIF group and 33 in the TLIF group. The median follow-up time was 24.0 months in both groups. The clinical outcomes and radiologic parameters significantly improved in both groups postoperatively. According to intergroup comparisons, the OLIF group had significantly less blood loss and superior improvement in radiologic parameters (DH, SL, and SCA) whereas the TLIF group had significantly shorter operation times. For the OLIF patients who did not undergo posterior decompression, the operation time was similar to that of the TLIF group, but the surgical blood loss and length of hospital stay were significantly reduced compared with the TLIF group. Conclusions: Compared with TLIF, OLIF provides similar clinical outcomes, leads to less surgical blood loss, and has superior radiologic parameters; however, the operation time is significantly longer. OLIF without posterior decompression may be a superior option to TLIF for certain patients. Full article

Objective: This study investigated the influence of the vacuum phenomenon (VP) on surgical outcomes in patients with lumbar spinal stenosis, comparing minimally invasive oblique lateral interbody fusion (MIS OLIF) and endoscopic decompression. Methods: A cohort of 110 patients diagnosed with lumbar spinal stenosis underwent either endoscopic decompression or MIS OLIF. Patients were classified into two groups based on the presence or absence of the VP on preoperative CT scans, non-VP (n = 42) and VP (n = 68). Radiologic and clinical outcomes, including back and leg pain assessed using the visual analogue scale (VAS), the Oswestry Disability Index (ODI), and the EuroQol-5 Dimension (Eq5D), were compared pre- and postoperatively over a 2-year follow-up period. Results: Preoperatively, the VP group exhibited significantly greater leg pain (p = 0.010), while no significant differences were observed in back pain or the ODI between the groups. In the non-VP group, decompression and fusion yielded similar outcomes, with decompression showing a better ODI score at 1 month (p = 0.018). In contrast, in the VP group, patients who underwent fusion showed significantly improved long-term leg pain outcomes compared to those who underwent decompression at both 1-year (p = 0.042) and 2-year (p = 0.017) follow-ups. Conclusions: The VP may indicate segmental instability and may play a role in the persistence of radiculopathy. Fusion surgery appears to offer better long-term relief in patients with the VP, whereas decompression alone is a viable option in non-VP cases. These findings suggest that the VP may be a useful factor in guiding surgical decision-making. Full article

Background: No consensus has been reached regarding the efficacy of indirect decompression through oblique lumbar interbody fusion (OLIF) in severe lumbar spinal stenosis (LSS). This study investigated the impact of preoperative magnetic resonance imaging (MRI)-based grading of central and foraminal stenosis on OLIF outcomes in LSS patients and identified risk factors for postoperative clinical dissatisfaction. Methods: We retrospectively reviewed LSS patients who underwent OLIF with a minimum 1-year follow-up. Clinical scores obtained preoperatively and at 3, 6, 12, and 24 months postoperatively were analyzed using the substantial clinical benefit (SCB) framework. The severity of central and foraminal stenosis in the initial MRI was assessed through qualitative grading systems. Results: Among the 145 patients, with a mean follow-up of 33.7 months, those with severe central stenosis showed a significantly higher proportion of patients achieving SCB in the visual analog scale for leg pain (94.5% versus 83.1%; p = 0.044) at one year postoperatively than those without. However, those with severe foraminal stenosis showed significantly higher Oswestry Disability Index (ODI) scores (p = 0.024), and lower walking ability scores in the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) (p = 0.004) at one year postoperatively than those without. The presence of a foraminal osteophyte of the superior articular process (SAP) was a significant risk factor responsible for not achieving SCB in ODI and walking ability in JOABPEQ at one year postoperatively (odds ratio: 0.20 and 0.22, respectively). Conclusions: After OLIF, patients with severe central stenosis showed clinical outcomes comparable to those without. The improvement in ODI and walking ability in JOABPEQ was limited in patients with severe foraminal stenosis. Surgeons should consider direct decompression in cases with the presence of foraminal osteophytes of SAP. Full article

Background: Standard oblique cages cannot cover endplates side-to-side, which is an important biomechanical factor for reducing the risk of cage subsidence and for restoring correct segmental lordosis. The aim of this study is to evaluate the radiological and clinical results of a new oblique lumbar interbody fusion (OLIF) axially expandable cage. Methods: This is a prospective observational case–control study. From March 2018 to June 2020, 28 consecutive patients with lumbar degenerative disease underwent an ATP approach, with the insertion of a new axially expandable cage, which was used as a stand-alone procedure or followed by posterior percutaneous pedicle fixation. Results: Twenty-eight patients in both groups met the inclusion criteria. The mean follow-up time was 31.2 months (range of 13–37). The clinical results were not significantly different, although in the control group, two major intraoperative complications were recorded, and slight improvements in ODI and SF-36 scores were observed in the study group. The radiological results showed a less frequent incidence of subsidence and a higher rate of fusion in the study group compared to controls. Conclusions: The axially expandable oblique cage for lumbar inter body fusion, specifically designed for the ATP approach, represents an innovation and a technical improvement. The insertion and the axial expansion technique are safe and easy. The large footprint could obtain solid and effective arthrodesis, potentially reducing the risk of subsidence. Full article

(1) Background: The amount of blood loss during oblique lumber interbody fusion (OLIF) surgery is often underestimated and may contribute to adverse postoperative outcomes. This study aims to evaluate hidden blood loss (HBL) in patients who underwent OLIF for degenerative lumbar spine disease and to analyze its risk factors. (2) Methods: The medical records of 179 patients who underwent OLIF surgery from 2015 to 2022 were reviewed. The HBL and total blood loss (TBL) were estimated using the Gross formula. Pearson correlation, Spearman correlation, and multivariate linear regression analyses were used to investigate risk factors for HBL. (3) Results: The mean HBL was 675.2 mL, and the mean hemoglobin loss was 1.7 g/dL during OLIF surgery. In the multivariate linear regression analysis, TBL (p < 0.001), estimated blood loss (p < 0.001), and pedicle screw fixation type (p = 0.039) were identified as independent risk factors of HBL. (4) Conclusions: The OLIF is associated with substantial perioperative HBL, for which we identified risk factors of TBL, EBL, and pedicle screw fixation type. Notably, OLIF with percutaneous pedicle screw fixation resulted in greater HBL than stand-alone OLIF or OLIF with open pedicle screw fixation. Full article

Lumbar interbody fusion procedures have seen a significant evolution over the years, with various approaches being developed to address spinal pathologies and instability, including posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), anterior lumbar interbody fusion (ALIF), and lateral lumbar interbody fusion (LLIF). LLIF, a pivotal technique in the field, initially emerged as extreme/direct lateral interbody fusion (XLIF/DLIF) before the development of oblique lumbar interbody fusion (OLIF). To ensure comprehensive circumferential stability, LLIF procedures are often combined with posterior stabilization (PS) using pedicle screws. However, achieving this required repositioning of the patient during the surgical procedure. The advent of single-position surgery (SPS) has revolutionized the procedure by eliminating the need for patient repositioning. With SPS, LLIF along with PS can be performed either in the lateral or prone position, resulting in significantly reduced operative time. Ongoing research endeavors are dedicated to further enhancing LLIF procedures making them even safer and easier. Notably, the integration of robotic technology into SPS has emerged as a game-changer, simplifying surgical processes and positioning itself as a vital asset for the future of spinal fusion surgery. This literature review aims to provide a succinct summary of the evolutionary trajectory of lumbar interbody fusion techniques, with a specific emphasis on its recent advancements. Full article

Background: Previous studies have identified various risk factors for adjacent segment disease (ASD) at the L5-S1 level after fusion surgery, including preoperative sagittal imbalance, longer fusion, and preoperative disc degeneration. However, only a few studies have explored the risk factors for ASD at the L5-S1 level after oblique lumbar interbody fusion (OLIF) at the L4-L5 level and above. This study aimed to identify the risk factors for symptomatic ASD at the L5-S1 level in patients with pre-existing degeneration after OLIF at L4-L5 and above. Methods: We retrospectively reviewed the data of patients who underwent OLIF at L4-L5 and above, with a minimum follow-up period of 2 years. Patients with central stenosis or Lee grade 2 or 3 foraminal stenosis at L5-S1 preoperatively were excluded. Patients were divided into ASD and non-ASD groups based on the occurrence of new-onset L5 or S1 radicular pain requiring epidural steroid injection (ESI). The clinical and radiological factors were analyzed. Logistic regression was used to identify the risk factors for ASD of L5-S1. Results: A total of 191 patients with a mean age ± standard deviation of 68.6 ± 8.3 years were included. Thirty-four (21.7%) patients underwent ESI at the L5 root after OLIF. In the logistic regression analyses, severe disc degeneration (OR (95% confidence interval (CI)): 2.65 (1.16–6.09)), the presence of facet effusion (OR (95% CI): 2.55 (1.05–6.23)), and severe paraspinal muscle fatty degeneration (OR (95% CI): 4.47 (1.53–13.05)) were significant risk factors for ASD in L5-S1. Conclusions: In this study, the presence of facet effusion, severe disc degeneration, and severe paraspinal muscle fatty degeneration at the L5-S1 level were associated with the development of ASD at L5-S1 following OLIF at L4-L5 and above. For patients with these conditions, surgeons could consider including L5-S1 in the fusion when considering OLIF at the L4-L5 level and above. Full article

The main advantage of Oblique Lumbar Interbody Fusion (OLIF) is its ability to provide safe access to the lumbar spine while being a robust interbody fusion technique through a minimally invasive approach. This study reviews the postoperative complications of OLIF, offering a comprehensive understanding of its advantages and disadvantages. A total of 27 studies with 1275 patients were shortlisted based on our selection criteria. Complications were categorized into intra-operative, immediate post-operative, and delayed post-operative and were interpreted based on surgical procedure into stand-alone OLIF, OLIF with posterior stabilisation, and unspecified. Major complications exhibited a pooled prevalence of just 1.7%, whereas the overall pooled prevalence of complications was 24.7%. Among the subgroups, the stand-alone subgroup had the lowest prevalence of complications (14.6%) compared to the unspecified subgroup (29.6%) and the OLIF L2-5 with posterior stabilisation subgroup (25.8%). Similarly, for major complications, the stand-alone subgroup had the lowest prevalence (1.4%), while the OLIF L2-5 with posterior stabilisation subgroup (1.8%) and the unspecified OLIF L2-5 subgroup (1.6%) had higher rates. However, the differences were not statistically significant. In conclusion, the rate of major complications after OLIF is minimal, making it a safe procedure with significant benefits outweighing the risks. The advantages of OLIF L2-5 with posterior stabilisation over stand-alone OLIF L2-5 is a subject of discussion. Full article