Defining cage subsidence in anterior, oblique, and lateral lumbar spine fusion approaches: a systematic review of the literature.

One of the most common complications of lumbar fusions is cage subsidence, which leads to collapse of disc height and reappearance of the presenting symptomology. However, definitions of cage subsidence are inconsistent, leading to a variety of subsidence calculation methodologies and thresholds. To review previously published literature on cage subsidence in order to present the most common methods for calculating and defining subsidence in the anterior lumbar interbody fusion (ALIF), oblique lateral interbody fusion (OLIF), and lateral lumbar interbody fusion (LLIF) approaches. A search was completed in PubMed and Embase with inclusion criteria focused on identifying any study that provided descriptions of the method, imaging modality, or subsidence threshold used to calculate the presence of cage subsidence. A total of 69 articles were included in the final analysis, of which 18 (26.1%) reported on the ALIF approach, 22 (31.9%) on the OLIF approach, and 31 (44.9%) on the LLIF approach, 2 of which reported on more than one approach. ALIF articles most commonly calculated the loss of disc height over time with a subsidence threshold of > 2 mm. Most OLIF articles calculated the total amount of cage migration into the vertebral bodies, with a threshold of > 2 mm. LLIF was the only approach in which most articles applied the same method for calculation, namely, a grading scale for classifying the loss of disc height over time. We recommend future articles adhere to the most common methodologies presented here to ensure accuracy and generalizability in reporting cage subsidence.

Oblique lateral interbody fusion at L5-S1: feasibility, surgical approach window, incision line, and influencing factors.

PURPOSE: The primary aim of this study was to describe the feasibility, surgical approach window (SAW), and incision line (IL) for oblique lateral interbody fusion at L5-S1 (OLIF51) using computed tomography (CT). A secondary aim was to identify associations among approach characteristics and demographic and anthropometric factors. METHODS: We performed a radiographic study of 50 male and 50 female subjects who received abdominal CT imaging. SAW was measured as the distance from the midline to the medial border of the iliac vessel. IL was measured at the skin surface corresponding to the distance between the center of the disc space and SAW lateral margin. OLIF51 feasibility was defined as the existence of at least a 1-cm SAW without retraction of soft tissues. RESULTS: For the left side, the OLIF51 SAW and IL were 12.1 ± 4.6 and 175.1 ± 55.3 mm. For the right side, these measures were 10.0 ± 4.3 and 185.0 ± 52.5 mm. Correlations of r = 0.648 (p < 0.001) and r = 0.656 (p < 0.001) were observed between weight and IL on the left and right sides, respectively. OLIF51 was not feasible 23% of the time. CONCLUSION: To our knowledge, this is the largest CT study to determine the feasibility of performing an OLIF51. Without the use of retraction, OLIF51 is not feasible 23% of the time. Left-sided OLIF51 allows for a larger surgical approach window and smaller incision compared to the right side. Larger incisions are required for adequate surgical exposure in patients with higher weight.

Oblique lateral interbody fusion for lumbosacral fractional curve correction in degenerative lumbar scoliosis.

PURPOSE: In combined anterior-posterior adult spinal deformity surgery, the optimal combination of anterior and posterior procedures remains unclear. We aimed to demonstrate the radiological outcomes and relevant factors in oblique lateral interbody fusion (OLIF) for lumbosacral fractional curve (FC) correction combined with open posterior surgery in degenerative lumbar scoliosis (DLS). METHODS: This study involved 42 consecutive patients with DLS who had a major curve (MC) ≥ 20° and an FC (L4 to S1) ≥ 10°, and underwent a combined anterior-posterior surgery Changes in the MC, FC, coronal balance distance, type of coronal imbalance, coronal/sagittal disc angle at L4-5 and L5-S1, L4 and L5 tilt, and sagittal parameters were examined. The associations between FC correction and demographic, surgical, and radiological factors were analysed. RESULTS: The FC decreased from 16.9 ± 7.3° preoperatively to 6.6 ± 4.4° at the last follow-up (P < 0.001). The coronal disc angle at L4-5 and L5-S1 were, respectively, 6.8 ± 2.2° and 6.0 ± 4.1° preoperatively and decreased to 2.2 ± 2.1 and 1.2 ± 1.3° at the last follow-up (both P < 0.001). The changes in FC were greater in uppermost instrumented level > T10 (P < 0.001), and associated with the preoperative FC (r = 0.820, P < 0.001), L4 tilt (r = 0.434, P = 0.007), and L5 tilt (r = 0.462, P = 0.003). CONCLUSION: OLIF at the FC combined with open posterior surgery is an effective combined anterior-posterior correction strategy in DLS.

Biomechanical evaluation of different oblique lumbar interbody fusion constructs: a finite element analysis.

BACKGROUND: Finite element analysis (FEA) was performed to investigate the biomechanical differences between different adjunct fixation methods for oblique lumbar interbody fusion (OLIF) and to further analyze its effect on adjacent segmental degeneration. METHODS: We built a single-segment (Si-segment) finite element model (FEM) for L4-5 and a double-segment (Do-segment) FEM for L3-5. Each complete FEM was supplemented and modified, and both developed two surgical models of OLIF with assisted internal fixation. They were OLIF with posterior bilateral percutaneous pedicle screw (TINA system) fixation (OLIF + BPS) and OLIF with lateral plate system (OLIF + LPS). The range of motion (ROM) and displacement of the vertebral body, cage stress, adjacent segment disc stress, and spinal ligament tension were recorded for the four models during flexion/extension, right/left bending, and right/left rotation by applying follower load. RESULTS: For the BPS and LPS systems in the six postures of flexion, extension, right/left bending, and right/left rotation, the ROM of L4 in the Si-segment FEM were 0.32°/1.83°, 0.33°/1.34°, 0.23°/0.47°, 0.24°/0.45°, 0.33°/0.79°, and 0.34°/0.62°; the ROM of L4 in the Do-segment FEM were 0.39°/2.00°, 0.37°/1.38°, 0.23°/0.47°, 0.21°/0.44°, 0.33°/0.57°, and 0.31°/0.62°, and the ROM of L3 in the Do-segment FEM were 6.03°/7.31°, 2.52°/3.50°, 4.21°/4.38°, 4.21°/4.42°, 2.09°/2.32°, and 2.07°/2.43°. BPS system had less vertebral displacement, less cage maximum stress, and less spinal ligament tension in Si/Do-segment FEM relative to the LPS system. BPS system had a smaller upper adjacent vertebral ROM, greater intervertebral disc stress in terms of left and right bending as well as left and right rotation compared to the LPS system in the L3-4 of the Do-segment FEM. There was little biomechanical difference between the same fixation system in the Si/Do-segment FEM. CONCLUSIONS: Our finite element analysis showed that compared to OLIF + LPS, OLIF + BPS (TINA) is more effective in reducing interbody stress and spinal ligament tension, and it better maintains the stability of the target segment and provides a better fusion environment to resist cage subsidence. However, OLIF + BPS (TINA) may be more likely to cause adjacent segment degeneration than OLIF + LPS.

Biomechanical changes of oblique lumbar interbody fusion with different fixation techniques in degenerative spondylolisthesis lumbar spine: a finite element analysis.

OBJECTIVE: There is a dearth of comprehensive research on the stability of the spinal biomechanical structure when combining Oblique Lumbar Interbody Fusion (OLIF) with internal fixation methods. Hence, we have devised this experiment to meticulously examine and analyze the biomechanical changes that arise from combining OLIF surgery with different internal fixation techniques in patients diagnosed with degenerative lumbar spondylolisthesis. METHODS: Seven validated finite element models were reconstructed based on computed tomography scan images of the L3-L5 segment. These models included the intact model, a stand-alone (S-A) OLIF model, a lateral screw rod (LSR) OLIF model, a bilateral pedicle screw (BPS) OLIF model, an unilateral pedicle screw (UPS) OLIF model, a bilateral CBT (BCBT) OLIF model, and an unilateral CBT(UCBT) OLIF model. The range of motion (ROM), as well as stress levels in the cage, L4 lower endplate, L5 upper endplate, and fixation constructs were assessed across these different model configurations. RESULTS: S-A model had the highest average ROM of six motion modes, followed by LSR, UPS, UCBT, BPS and BCBT. The BCBT model had a relatively lower cage stress than the others. The maximum peak von Mises stress of the fixation constructs was found in the LSR model. The maximum peak von Mises stress of L4 lower endplate was found in the S-A model. The peak von Mises stress on the L4 lower endplate of the rest surgical models showed no significant difference. The maximum peak von Mises stress of the L5 upper endplate was found in the S-A model. The minimum peak von Mises stress of the L5 upper endplate was found in the BCBT model. No significant difference was found for the peak von Mises stress of the L5 upper endplate among LSR, BPS, UPS and UCBT models. CONCLUSION: Among the six different fixation techniques, BCBT exhibited superior biomechanical stability and minimal stress on the cage-endplate interface. It was followed by BPS, UCBT, UPS, and LSR in terms of effectiveness. Conversely, S-A OLIF demonstrated the least stability and resulted in increased stress on both the cage and endplates. Combining OLIF with BCBT fixation technique enhanced biomechanical stability compared to BPS and presented as a less invasive alternative treatment for patients with degenerative lumbar spondylolisthesis.

Clinical and Radiologic Analysis of Minimally Invasive Anterior-Posterior Combined Surgery for Adult Spinal Deformity: Comparison of Oblique Lateral Interbody Fusion at L5/S1 (OLIF51) versus Transforaminal Interbody Fusion.

Background and Objectives: Although adult spinal deformity (ASD) surgery brought about improvement in the quality of life of patients, it is accompanied by high invasiveness and several complications. Specifically, mechanical complications of rod fracture, instrumentation failures, and pseudarthrosis are still unsolved issues. To better improve these problems, oblique lateral interbody fusion at L5/S1 (OLIF51) was introduced in 2015 at my institution. The objective of this study was to compare the clinical and radiologic outcomes of anterior-posterior combined surgery for ASD between the use of OLIF51 and transforaminal interbody fusion (TLIF) at L5/S1. Materials and Methods: A total of 117 ASD patients received anterior-posterior correction surgeries either with the use of OLIF51 (35 patients) or L5/S1 TLIF (82 patients). In both groups, L1-5 OLIF and minimally invasive posterior procedures of hybrid or circumferential MIS were employed. The sagittal and coronal spinal alignment and spino-pelvic parameters were recorded preoperatively and at follow-up. The quality-of-life parameters and visual analogue scale were evaluated, as well as surgical complications at follow-up. Results: The average follow-up period was thirty months (13-84). The number of average fused segments was eight (4-12). The operation time and estimated blood loss were significantly lower in OLIF51 than in TLIF. The PI-LL mismatch, LLL, L5/S1 segmental lordosis, and L5 coronal tilt were significantly better in OLIF51 than TLIF. The complication rate was statistically equivalent between the two groups. Conclusions: The introduction of OLIF51 for adult spine deformity surgery led to a decrease in operation time and estimated blood loss, as well as improvement in sagittal and coronal correction compared to TLIF. The circumferential MIS correction and fusion with OLIF51 serve as an effective surgical modality which can be applied to many cases of adult spinal deformity.

CT-based analysis of oblique lateral interbody fusion from L1 to L5: location of incision, feasibility of safe corridor approach, and influencing factors.

PURPOSE: The primary aim was to measure the safe corridor (SC), surgical incision anterior margin (AM), and posterior margin (PM) for OLIF bilaterally from L1 to L5. The secondary aim was to determine the feasibility of approach via the SC. The tertiary aim was to analyze the influence of demographic and anthropometric factors on OLIF parameters. METHODS: We performed a radiographic analysis of 100 subjects who received an abdominal CT. Measurements of the AM, PM, and SC were obtained as well as patient age, sex, height, weight, and BMI. The intraclass correlation coefficient was used to evaluate interrater reliability. To assess associations among variables, Pearson's correlation tests and multivariate linear regression models were constructed. Sex differences were analyzed using Student's t tests. RESULTS: At L1-2, L2-3, L3-4, and L4-5, the PM was 6.6, 8.2, 9.4, and 10.2 cm on the left side and 7.2, 7.7, 8.8, and 9.5 cm on the right side in relation to the disk space center. The SC was less than 1 cm 1%, 3%,3%, and 18% of the time on the left side, and 15%, 12%,29%, and 60% on the right side. None of the anthropometric factors demonstrated a strong correlation with incision location. SC was larger on the left side. Interrater ICC was .934. CONCLUSIONS: This study is the first to provide guidelines on the appropriate location of the incision line during OLIF based on SC from L1 to L5. SC measurements do not vary by sex. OLIF is more feasible via a left-sided approach.

Concentration-Dependent Efficacy of Recombinant Human Bone Morphogenetic Protein-2 Using a HA/ß-TCP Hydrogel Carrier in a Mini-Pig Vertebral Oblique Lateral Interbody Fusion Model.

Bone morphogenetic protein-2 (BMP-2) is used in the treatment of degenerative spinal disease and vertebral fractures, spine fusion, dental surgery, and facial surgery. However, high doses are associated with side effects such as inflammation and osteophytes. In this study, we performed spinal fusion surgery on mini-pigs using BMP-2 and a HA/ß-TCP hydrogel carrier, and evaluated the degree of fusion and osteophyte growth according to time and dosage. Increasing the dose of BMP-2 led to a significantly higher fusion rate than was observed in the control group, and there was no significant difference between the 8-week and 16-week samples. We also found that the HA + ß-TCP hydrogel combination helped maintain the rate of BMP-2 release. In conclusion, the BMP-2-loaded HA/ß-TCP hydrogel carrier used in this study overcame the drawback of potentially causing side effects when used at high concentrations by enabling the sustained release of BMP-2. This method is also highly efficient, since it provides mineral matter to accelerate the fusion rate of the spine and improve bone quality.

Incidence of major and minor vascular injuries during lateral access lumbar interbody fusion procedures: a retrospective comparative study and systematic literature review.

During lateral lumbar fusion, the trajectory of implant insertion approaches the great vessels anteriorly and the segmental arteries posteriorly, which carries the risk of vascular complications. We aimed to analyze vascular injuries for potential differences between oblique lateral interbody fusion (OLIF) and lateral lumbar interbody fusion (LLIF) procedures at our institution. This was coupled with a systematic literature review of vascular complications associated with lateral lumbar fusions. A retrospective chart review was completed to identify consecutive patients who underwent lateral access fusions. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used for the systematic review with the search terms "vascular injury" and "lateral lumbar surgery." Of 260 procedures performed at our institution, 211 (81.2%) patients underwent an LLIF and 49 (18.8%) underwent an OLIF. There were no major vascular complications in either group in this comparative study, but there were four (1.5%) minor vascular injuries (2 LLIF, 0.95%; 2 OLIF, 4.1%). Patients who experienced vascular injury experienced a greater amount of blood loss than those who did not (227.5 ± 147.28 vs. 59.32 ± 68.30 ml) (p = 0.11). In our systematic review of 63 articles, major vascular injury occurred in 0-15.4% and minor vascular injury occurred in 0-6% of lateral lumbar fusions. The systematic review and comparative study demonstrate an increased rate of vascular injury in OLIF when compared to LLIF. However, vascular injuries in either procedure are rare, and this study aids previous literature to support the safety of both approaches.

Oblique lateral interbody fusion combined with different internal fixations for the treatment of degenerative lumbar spine disease: a finite element analysis.

BACKGROUND: Little is known about the biomechanical performance of different internal fixations in oblique lumbar interbody fusion (OLIF). Here, finite element (FE) analysis was used to describe the biomechanics of various internal fixations and compare and explore the stability of each fixation. METHODS: CT scans of a patient with lumbar degenerative disease were performed, and the l3-S1 model was constructed using relevant software. The other five FE models were constructed by simulating the model operation and adding different related implants, including (1) an intact model, (2) a stand-alone (SA) model with no instrument, (3) a unilateral pedicle screw model (UPS), (4) a unilateral pedicle screw contralateral translaminar facet screw model (UPS-CTFS), (5) a bilateral pedicle screw (BPS) model, and (6) a cortical bone trajectory screw model (CBT). Various motion loads were set by FE software to simulate lumbar vertebral activity. The software was also used to extract the range of motion (ROM) of the surgical segment, CAGE and fixation stress in the different models. RESULTS: The SA group had the greatest ROM and CAGE stress. The ROM of the BPS and UPS-CTFS was not significantly different among motion loadings. Compared with the other three models, the BPS model had lower internal fixation stress among loading conditions, and the CBT screw internal fixation had the highest stress among loads. CONCLUSIONS: The BPS model provided the best biomechanical stability for OLIF. The SA model was relatively less stable. The UPS-CTFS group had reduced ROM in the fusion segments, but the stresses on the internal fixation and CAGE were relatively higher in the than in the BPS group; the CBT group had a lower flexion and extension ROM and higher rotation and lateral flexion ROM than the BPS group. The stability of the CBT group was poorer than that of the BPS and LPS-CTFS groups. The CAGE and internal fixation stress was greater in the CBT group.

Comparison of transfacet and pedicle screws in oblique lateral interbody fusion for single-level degenerative lumbar spine diseases: a retrospective propensity score-matched analysis.

BACKGROUND: To perform a comparative assessment of percutaneous transfacet screws (TFS) and percutaneous bilateral pedicle screws (BPS) in oblique lateral interbody fusion (OLIF) for the treatment of single-level degenerative lumbar spine diseases in terms of radiological examinations and clinical outcomes. METHODS: Sixty-six patients who received single-level OLIF with percutaneous supplementary fixation assisted by the robot for the treatment of degenerative lumbar spine diseases were selected. There were 16 cases of OLIF with TFS and 50 cases of OLIF with BPS. The propensity score matching method selected 11 patients in each group with matched characteristics to perform a clinical comparison. RESULTS: The estimated blood loss was 68.2 ± 25.2 ml in the OLIF with TFS group compared to 113.6 ± 39.3 ml in the OLIF with BPS group (P < 0.05). The intervertebral disc height raised from 8.6 to 12.9 mm in the TFS group and from 8.9 to 13.9 mm in the BPS group in the immediate postoperative period, and dropped to 10.8 and 12.9 mm at the twelfth month, respectively (P < 0.05). The fusion rates were 91% and 100% for TFS and BPS groups (P > 0.05). Quantitative assessments of back/leg pain of the two groups reached a healthy level in the late period of the follow-up. CONCLUSION: Both TFS and BPS techniques for the OLIF surgery relieve back pain caused by degenerative lumbar spine diseases. The TFS technique exhibits less blood loss compared with the BPS. A moderate cage subsidence is present in TFS but no complication is reported.

Substantially High Hidden Blood Loss in Oblique Lateral Interbody Fusion: Retrospective Case Series.

Background and Objectives: Measured blood loss frequently underestimates true blood loss; this discrepancy is called hidden blood loss (HBL). The purpose of the present study was to measure HBL in oblique lateral interbody fusion (OLIF). Materials and Methods: Patients who underwent two-stage OLIF at our institute from September 2017 to September 2021 were retrospectively reviewed. Total blood loss (TBL) and HBL were calculated using the gross formula. The age, sex, body mass index (BMI), operation time, measured blood loss, the number of fused segments, hematocrit (HCT), anticoagulant or platelet medication, blood transfusion, days of hospitalization, pre-/postoperative Japanese Orthopedic Association (JOA) score, and JOA recovery rate were compared. Results: A total of thirteen patients were included in the study. The average age, BMI, number of fused segments, operation time, estimated blood loss, and blood transfusion were 69.5 years, 23.3, 2.5, 250 min, 122 mL, and 230 mL, respectively. Five patients received anticoagulant or platelet therapy. Days of hospitalization, pre-/postoperative JOA score, and JOA recovery rate were 14.9 ± 5.1, 19.9 ± 2.7, and 18.0 ± 43.4%, respectively. The TBL and HBL were 688 and 797 mL, respectively. Stepwise multiple regression analysis revealed that younger age (p = 0.01), female sex (p = 0.01), and number of fused segments (p = 0.02) were significantly associated with higher HBL. Conclusions: The HBL in OLIF was 797 mL, which was more than other previously reported procedures. Therefore, OLIF may not be less invasive in terms of HBL. Blood loss after surgery should be considered, especially when patients are younger, are female, and have a greater number of fused segments.

Single-stage debridement via autogenous iliac bone graft through the OLIF corridor and lateral fixation in treating spontaneous single-level lumbar pyogenic spondylodiscitis.

BACKGROUND: The aim of the present study was to investigate the efficacy and safety of mini-open oblique debridement and lumbar interbody fusion combined with lateral screw fixation for treating single-level pyogenic spondylodiscitis. METHODS: Twelve patients with single-level lumbar pyogenic spondylodiscitis underwent OLIF combined with lateral screw fixation were analyzed. Patients underwent follow-up for 12 to 24 months. The clinical characteristics, etiological examinations, operative time, intraoperative blood loss, Oswestry Disability Index (ODI), visual analog scale score (VAS), postoperative complications, and the bony fusion rate were recorded. RESULTS: The mean follow-up period of time was 14.8 months. The average operative time and intra-operative blood loss were 129.0 ± 19.76 min and 309.2 ± 92.96 mL, respectively. No severe intra-operative complications were observed during surgery, except in 1 case that develops abdominal pain and distension after surgery, 2 cases that develop left-sided transient thigh pain/numbness and 8 cases that complains of donor site (iliac crest) pain. All of these symptoms disappeared 8 weeks after surgery. Tissue sample cultures were obtained from all patients intraoperatively and four (33.3%) were positive, including 2 with Staphylococcus aureus, 1 with Staphylococcus epidermidis, and 1 with Escherichia coli. During an average of 22.5 ± 2.1 days (range, 14-29 days) after surgery, WBC, CPR, and ESR levels in all patients had returned to normal. All patients were pain free with no recurring infection. Solid bony fusions were observed in all cases within 6 months, including 10 with I grade fusion, 2 with II grade fusion according to the classification suggested by Burkus et al. No fixation failure was observed during follow up and solid bony fusions were observed in all 12 patients at finally follow-up. A significant postoperative increase was also observed in the mean segmental height and lordosis (P < 0.05), followed by a slight decrease of segmental height and lordosis at final follow-up. At the final follow up, the mean VAS (1.5 ± 0.6) and ODI (18.9 ± 7.6) were significantly lower than VAS (8.4 ± 2.7) and ODI (71.2 ± 16.5) before surgery (P < 0.01). CONCLUSION: Single-stage debridement with autogenous iliac bone graft through the OLIF corridor and lateral fixation was a feasible surgical approach in our consecutive 12 cases of pyogenic spondylitis.

Minimally invasive transforaminal lumbar interbody fusion versus oblique lateral interbody fusion for lumbar degenerative disease: a meta-analysis.

BACKGROUND: Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and oblique lateral interbody fusion (OLIF) are widely used in the treatment of lumbar degenerative diseases. In the present study, a meta-analysis was conducted to compare the clinical and radiographic efficacy of these two procedures. METHODS: A systematic literature review was performed, and the quality of retrieved studies was evaluated with the Newcastle-Ottawa Scale (NOS). Clinical outcomes, including operation time, intraoperative blood loss, improvement in Visual Analogue Scale (VAS), improvement in Oswestry Disability Index (ODI), Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) effectiveness rate and complications, in addition to radiographic outcomes, including restoration of disc height, disc angle, overall lumbar lordosis, fusion rate and subsidence, were extracted and input into a fixed or random effect model to compare the efficacy of MIS-TLIF and OLIF. RESULTS: Seven qualified studies were included. Clinically, OLIF resulted in less intraoperative blood loss and shorter operation time than MIS-TLIF. Improvement of VAS for leg pain was more obvious in the OLIF group (P < 0.0001), whereas improvement of VAS for back pain (P = 0.08) and ODI (P = 0.98) as well as JOABPEQ effectiveness rate (P = 0.18) were similar in the two groups. Radiographically, OLIF was more effective in restoring disc height (P = 0.01) and equivalent in improving the disc angle (P = 0.18) and lumbar lordosis (P = 0.48) compared with MIS-TLIF. The fusion rate (P = 0.11) was similar in both groups, while the subsidence was more severe in the MIS-TLIF group (P < 0.00001). CONCLUSIONS: The above evidence suggests that OLIF is associated with a shorter operation time (with supplementary fixation in the prone position) and less intraoperative blood loss than MIS-TLIF and can lead to better leg pain alleviation, disc height restoration and subsidence resistance. No differences regarding back pain relief, functional recovery, complications, disc angle restoration, lumbar lordosis restoration and fusion rate were found. However, due to the limited number of studies, our results should be confirmed with high-level studies to fully compare the therapeutic efficacy of MIS-TLIF and OLIF. TRIAL REGISTRATION: PROSPERO ID:  CRD42020201903 .

Vascular anatomy and surgical approach in oblique lateral interbody fusion at lumbosacral transitional vertebrae.

BACKGROUND: Oblique lateral interbody fusion (OLIF) at lumbosacral junction is typically performed on the central window between the bifurcations of iliac vessels. However, the central window of lumbosacral transitional vertebrae (LSTVs) is usually obstructed by the iliocaval venous structures. We aimed to describe the vascular anatomy and surgical approach in OLIF at LSTVs compared with those in OLIF at typical L5-S1 junction. METHODS: Sixty-eight consecutive patients who underwent OLIF at lumbosacral junction were included. Of these, 31 patients had LSTVs and 37 patients had typical L5-S1 junction. The position of the iliocaval junction and the configuration of the left common iliac vein were compared using the preoperative CT and MR images of the lumbar spine. The surgical approach and intraoperative vascular findings were analyzed. RESULTS: Almost 70% of LSTVs had the iliocaval junction at low or very low position. Mobilization of left common iliac vein for central window was potentially difficult in almost 74% of OLIF at LSTVs while it was not required or was potentially easy in almost 80% of OLIF at typical L5-S1. Vascular injury was identified in 2 (6.5%) patients with OLIF at LSTVs and in 3 (8.1%) patients with OLIF at typical L5-S1 junction (P = 0.904). CONCLUSIONS: In our series, OLIF at LSTVs was performed through lateral window in 93.5% of the cases. Preoperative evaluation of the iliocaval junction using CT/MR of lumbar spine was reliable and valid in the determination of OLIF approach at lumbosacral junction.

Clinical Evaluation of Microendoscopy-Assisted Oblique Lateral Interbody Fusion.

Background and objectives: Oblique Lateral Interbody Fusion (OLIF) is a widely performed, minimally invasive technique to achieve lumbar lateral interbody fusion. However, some complications can arise due to constraints posed by the limited surgical space and visual field. The purpose of this study was to assess the short-term postoperative clinical outcomes of microendoscopy-assisted OLIF (ME-OLIF) compared to conventional OLIF. Materials and Methods: We retrospectively investigated 75 consecutive patients who underwent OLIF or ME-OLIF. The age, sex, diagnosis, and number of fused levels were obtained from medical records. Operation time, estimated blood loss (EBL), and intraoperative complications were also collected. Operation time and EBL were only measured per level required for the lateral procedure, excluding the posterior fixation surgery. The primary outcome measure was assessed using the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ). The secondary outcome measure was assessed using the Oswestry Disability Index (ODI) and the European Quality of Life-5 Dimensions (EQ-5D), measured preoperatively and 1-year postoperatively. Results: This case series consisted of 14 patients in the OLIF group and 61 patients in the ME-OLIF group. There was no significant difference between the two groups in terms of the mean operative time and EBL (p = 0.90 and p = 0.50, respectively). The perioperative complication rate was 21.4% in the OLIF group and 21.3% in the ME-OLIF group (p = 0.99). In both groups, the postoperative JOABPEQ, EQ-5D, and ODI scores improved significantly (p < 0.001). Conclusions: Although there was no significant difference in clinical results between the two surgical methods, the results suggest that both are safe surgical methods and that microendoscopy-assisted OLIF could serve as a potential alternative to the conventional OLIF procedure.

PEEK versus titanium cages in lateral lumbar interbody fusion: a comparative analysis of subsidence.

OBJECTIVE: The authors have provided a review of radiographic subsidence after lateral lumbar interbody fusion (LLIF) as a comparative analysis between titanium and polyetheretherketone (PEEK) cages. Many authors describe a reluctance to use titanium cages in spinal fusion secondary to subsidence concerns due to the increased modulus of elasticity of metal cages. The authors intend for this report to provide observational data regarding the juxtaposition of these two materials in the LLIF domain. METHODS: A retrospective review of a prospectively maintained database identified 113 consecutive patients undergoing lateral fusion for degenerative indications from January to December 2017. The surgeons performing the cage implantations were two orthopedic spine surgeons and two neurosurgeons. Plain standing radiographs were obtained at 1-2 weeks, 8-12 weeks, and 12 months postoperatively. Using a validated grading system, interbody subsidence into the endplates was graded at these time points on a scale of 0 to III. The primary outcome measure was subsidence between the two groups. Secondary outcomes were analyzed as well. RESULTS: Of the 113 patients in the sample, groups receiving PEEK and titanium implants were closely matched at 57 and 56 patients, respectively. Cumulatively, 156 cages were inserted and recombinant human bone morphogenetic protein-2 (rhBMP-2) was used in 38.1%. The average patient age was 60.4 years and average follow-up was 75.1 weeks. Subsidence in the titanium group in this study was less common than in the PEEK cage group. At early follow-up, groups had similar subsidence outcomes. Statistical significance was reached at the 8- to 12-week and 52-week follow-ups, demonstrating more subsidence in the PEEK cage group than the titanium cage group. rhBMP-2 usage was also highly correlated with higher subsidence rates at all 3 follow-up time points. Age was correlated with higher subsidence rates in univariate and multivariate analysis. CONCLUSIONS: Titanium cages were associated with lower subsidence rates than PEEK cages in this investigation. Usage of rhBMP-2 was also robustly associated with higher endplate subsidence. Each additional year of age correlated with an increased subsidence risk. Subsidence in LLIF is likely a response to a myriad of factors that include but are certainly not limited to cage material. Hence, the avoidance of titanium interbody implants secondary solely to concerns over a modulus of elasticity likely overlooks other variables of equal or greater importance.

[Effects of oblique lateral interbody fusion and transforaminal lumbar interbody fusion for lordosis correction in degenerative lumbar diseases].

Objective: To compare the operation time, estimated blood loss, clinical outcome and correction of lumbar lordosis between oblique lateral interbody fusion (OLIF) and transforaminal lumbar interbody fusion (TLIF) in patients with degenerative lumbar diseases. Methods: Seventy-three patients who underwent OLIF or TLIF surgery from January 2016 to December 2017 in Sir Run Run Shaw Hospital Zhejiang University were analyzed in this retrospective case-control study. The patients included 31 males and 42 females, with a mean age of 65.8 years (range, 36-88 years). Of the patients, there were 9 cases of calcified disc herniation, 34 cases of spinal stenosis, 17 cases of degenerative spondylolithesis, 12 cases of degenerative scoliosis and 1 case of isthmic spondylolithesis. According to the type of surgery, patients were divided into OLIF group (34 cases) and TLIF group (39 cases). The operation time, estimated blood loss and transfusion were recorded, pre-and post-operative visual analogue scale (VAS) for back pain and Oswestry Disability Index (ODI) were evaluated, and pre- and post-operative lumbar lordosis (LL) and fused segment lordosis (FSL) were measured. Student t test were used in comparison between groups. Results: Ten (29.4%) patients in OLIF group and all 39 (100%) patients in TLIF group were supplemented with posterior instrumentation (χ(2)=41.013, P<0.05). The average operation time and estimated blood loss was significantly lower in OLIF group than in those in TLIF group[(163±68) vs (233±79) min, (116±148) vs (434±201) ml, t=4.019, 6.964, both P<0.05]. There was no significant differences in decreases value in VAS and ODI after surgery between the two groups (t=1.716, 0.522, both P>0.05). The correction of LL was 4.0°±10.0° in the OLIF group and 4.2°±6.1° in the TLIF group; the correction of FSL was 4.1°±7.0° in the OLIF group and 5.2°±4.6° in the TLIF group, with no significant differences between the two groups too (t=0.139, 0.805, both P>0.05). The correction of LL was significantly higher in OLIF group with posterior instrumentation than that in TLIF group (9.9°±11.1° vs 4.2°±6.1°, t=2.180, P<0.05). Conclusions: Both OLIF and TLIF can restore LL to some extent, but OLIF has obvious advantages in the operation time and blood loss during surgery. When supplemented with posterior instrumentation, OLIF can achieve better correction of LL than TLIF.

Radiographic evaluation of indirect decompression of mini-open anterior retroperitoneal lumbar interbody fusion: oblique lateral interbody fusion for degenerated lumbar spondylolisthesis.

PURPOSE: Extreme lateral interbody fusion provides minimally invasive treatment of spinal deformity, but complications including nerve and psoas muscle injury have been noted. To avoid nerve injury, mini-open anterior retroperitoneal lumbar interbody fusion methods using an approach between the aorta and psoas, such as oblique lumbar interbody fusion (OLIF) have been applied. OLIF with percutaneous pedicle screws without posterior decompression can indirectly decompress the spinal canal in lumbar degenerated spondylolisthesis. In the current study, we examined the radiographic and clinical efficacy of OLIF for lumbar degenerated spondylolisthesis. METHODS: We assessed 20 patients with lumbar degenerated spondylolisthesis who underwent OLIF and percutaneous pedicle screw fixation without posterior laminectomy. MR and CT images and clinical symptoms were evaluated before and 6 months after surgery. Cross sections of the spinal canal were evaluated with MRI, and disk height, cross-sectional areas of intervertebral foramina, and degree of upper vertebral slip were evaluated with CT. Clinical symptoms including low back pain, leg pain, and lower extremity numbness were evaluated using a visual analog scale and the Oswestry Disability Index before and 6 months after surgery. RESULTS: After surgery, significant increases in axial and sagittal spinal canal diameter (12 and 32 %), spinal canal area (19 %), disk height (61 %), and intervertebral foramen areas (21 % on the right side, 39 % on the left), and significant decrease of upper vertebral slip (-9 %) were found (P < 0.05). Low back pain, leg pain, and lower extremity numbness were significantly reduced compared with before surgery (P < 0.05). CONCLUSIONS: Significant improvements in disk height and spinal canal area were found after surgery. Bulging of disks was reduced through correction, and stretching the yellow ligament may have decompressed the spinal canal. Lumbar anterolateral fusion without laminectomy may be useful for lumbar spondylolisthesis with back and leg symptoms.

Preoperative evaluation of left common iliac vein in oblique lateral interbody fusion at L5-S1.

PURPOSE: Oblique lateral interbody fusion (OLIF) L5-S1 is essentially to perform an anterior lumbar interbody fusion (ALIF) in the lateral position. Because the surgical procedures are performed "obliquely" over the left common iliac vein (LCIV), ensuring that the vein is protected which is particularly important. We aimed to evaluate the configuration of LCIV and its risk of mobilization during anterior approach at L5-S1 segment. METHODS: This study involved 65 consecutive patients who underwent anterior lumbar fusion (ALIF, n = 39; OLIF, n = 26) at the L5-S1 segment. Three independent examiners evaluated the configuration of the LCIV at the L5-S1 disc on axial magnetic resonance images of the lumbar spine. The LCIV was categorized into three types according to the difficulty of mobilization: type I (no requirement for mobilization; LCIV runs laterally for more than two-thirds of the length of the left side of the L5-S1 disc), type II (easy mobilization; LCIV obstructs the L5-S1 disc space, but the perivascular adipose tissue is present under the LCIV), and type III (potentially difficult mobilization; no perivascular adipose tissue under the LCIV). The patient records were reviewed for vascular complications. RESULTS: There were 21 men and 44 women in this study, with a mean age of 63.4 years (range 19-83 years). Type I LCIV configuration was found in 32 (49.2%) patients, type II in 18 (27.7%), and type III in 15 (23.1%). There were 7 (10.8%) patients with LCIV injury (type I, n = 0; type II, n = 2; type III, n = 5) (P = 0.003). Intraobserver reliability for the LCIV classification ranged from substantial to excellent, and interobserver reliability ranged from moderate to excellent. CONCLUSIONS: Preoperative evaluation for anterior approach to the L5-S1 segment should take account of the LCIV position, as well as the difficulty of its mobilization. The type III LCIV configuration showed a high rate of vascular injury.