Extreme Lateral Interbody Fusion Research Articles

Oblique Lateral Versus Extreme Lateral as Approaches for Lumbar Disc Inter-Body Fusion

Abstract Background In the current surgical therapeutic regimen for the degenerative lumbar disease, both oblique lateral interbody fusion (OLIF) and extreme lateral lumbar interbody fusion (LLIF) are gradually accepted. Aim of the Work In this research, we aimed to compare the radiographic and clinical outcomes of OLIF and XLIF for the degenerative lumbar disease. Subjects and Methods This was a Meta-analysis study, The review considered case-control studies, case report studies, and retrospective case follow-up comparing radiographic and clinical outcomes of OLIF and XLIF for the degenerative lumbar disease. Results Change in Oswestry disability index (ODI) was reported in 9 studies. The effect estimate is - 28.247 with Random model applied. There is heterogeneity p = 0.001.Moreover, it was noted that change in visual analog scale (VAS) was reported in all 10 studies. The effect estimate is -3.796 with Random model applied. There is heterogeneity p < 0.001. Conclusion The two groups are similar in terms of radiographic outcomes, operative blood loss, operative time and the length of hospital stay. The OLIF group shows advantages in VAS and ODI scores improvement. Though the incidence of perioperative complications of OLIF and LLIF is similar, the incidence of main complications is significantly different.

"OssDsign Catalyst® Bone Graft Performance in a Three- Level Extreme Lateral Interbody Fusion (XLIF®)"

"OssDsign Catalyst® Bone Graft Performance in a Three- Level Extreme Lateral Interbody Fusion (XLIF®)"

A retrospective case-control study on the effectiveness of preoperative diffusion tensor imaging for mitigating nerve injury in extreme lateral interbody fusion surgery

Extreme Lateral Interbody Fusion (XLIF) has been established as an effective treatment for degenerative disorders of the lumbar spine. Nevertheless, there is a potential risk of lumbar plexus damage associated with XLIF, especially during surgeries at the L4-5 segment. Diffusion Tensor Imaging (DTI) evaluates the directional diffusion of water molecules in tissue, providing a more intricate depiction of internal tissue microstructure compared to conventional MRI techniques. The capability of DTI sequences to elucidate the 3-dimensional interplay between lumbar nerve pathways and adjacent musculoskeletal structures, potentially reducing the incidence of nerve injury complications related to XLIF, remains to be established. This study evaluates the effectiveness of preoperative Diffusion Tensor Imaging (DTI) in reducing neurological complications after Extreme Lateral Interbody Fusion (XLIF) surgeries at the L4-5 level, focusing on the interaction between lumbar nerves and the psoas major muscle. Retrospective case-control study. The study included 128 patients undergoing XLIF surgery for degenerative disorders at the L4-5 segment: 68 in the traditional group and 62 in the DTI group. The study assessed Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) scores, along with complication rates. It also documented psoas major muscle morphology and its correlation with nerve pathways. A retrospective analysis of 128 patients undergoing XLIF surgery for degenerative disorders at the L4-5 segment between February 2020 and August 2022 was conducted. The cohort was divided into a traditional group (68 patients) receiving presurgery MRI scans to identify surgical entry points at the intervertebral space midpoint (Zones II-III junction) and a DTI group (62 patients) who additionally underwent preoperative DTI to customize entry points. The study evaluated VAS and ODI scores, complication rates, psoas major muscle morphology, and its interaction with nerve pathways. The traditional group uniformly chose the Zone II-III junction for entry. In contrast, the DTI group's entry points varied. Postoperative follow-up revealed significant improvements in VAS and ODI scores in both groups. However, the DTI group experienced fewer immediate postoperative complications such as thigh pain, numbness, and motor disturbances. The study also noted a ventral shift in nerve positioning in patients with elevated psoas muscles. Preoperative DTI effectively maps the relationship between the psoas major muscle and lumbar nerves. Tailoring surgical entry points based on DTI results significantly reduces the risk of nerve damage in XLIF surgeries. The study underscores the importance of recognizing variability in lumbar nerve pathways due to differing psoas muscle morphologies, highlighting a higher risk of nerve injury in patients with elevated psoas muscles during XLIF procedures.

Anatomical study of the relationship between the lumbar intervertebral disc, nerves, and psoas major.

Cadaveric study; To describe the characteristics of the nerve and its relationship with the lumbar intervertebral disc and psoas major muscle. Nerve injury is an understudied complication of extreme lateral interbody fusion. A detailed description of the nerve anatomy would be helpful for surgeons to minimize the risk of this complication. The lumbar plexus and lumbar sympathetic nerve of 10 embalmed male cadavers were dissected, and the distribution, number, and spatial orientation of the nerves on the L1/2 to L4/5 intervertebral discs were examined. Metal wires were applied along nerve paths through the psoas major muscle. The position of the nerves was examined on CT. In zone III at L1/2 and L4/5, no nerves were found. In zone II and zone III at L2/3, no lumbar plexus was found, and only the ramus communicans passed through. At the L1-L5 level, the density of nerves in the posterior half of the psoas major muscle was greater than that in the anterior half. The lumbar plexus was found in all of zone IV. The genitofemoral nerve emerges superficially and anteriorly from the medial border of the psoas major at the L3-4 level, but at the L1/2 level, the sympathetic trunk is located in zone II. The remaining disc-level sympathetic trunks appear in zone I. No nerves were found in zone III of the L1/2 or L4/5 disc. In zones II and III of L2/3, the lumbar plexus appears safe. The genitofemoral nerve travels through zones II and III of L3/4. The distribution density of nerves in the posterior half of the psoas major muscle was greater than that in the anterior half of that muscle at the L1-L5 level.

Efficacy and Safety of the Extreme Lateral Interbody Fusion (XLIF) Technique in Spine Surgery: Meta-Analysis of 1409 Patients.

(1) Objectives: The objective of this study was to quantify the exact clinical-radiological efficacy and safety of the extreme lateral interbody fusion (XLIF) technique in spinal surgery; (2) Methods: A meta-analysis was performed using PubMed, Embase, Scopus, and Cochrane Collaboration Library. Studies focusing on patients surgically treated with XLIF were included. The outcomes were as follows: visual analog scale (VAS) and Oswestry disability index (ODI), radiological outcomes, and adverse events. Cohort studies and case series were also included. Clinical outcomes were assessed at 12 months of age. Data were combined using Review Manager 5.4 and WebPlotDigitizer 13.1.4; (3) Results: Nineteen studies with a pool of 1409 patients were included in this meta-analysis. Leg pain VAS and back pain VAS significantly improved at 12 months (SMD 2.75, 95% CI 0.59-4.90; SMD 4.54, 95% CI 1.39-7.69). ODI showed significant improvement (MD 32.51, 95% CI 24.01-41.00) at 12 months. Disc height increased significantly (SMD -2.73, 95% CI -3.58 to -1.88). Lumbar lordosis and segmental lordosis were significantly corrected postoperatively (MD -2.44, 95% CI -3.45 to -1.43; MD -2.55, 95% CI -3.61 to -1.48). The fusion rates at 12 months ranged from 85.0% to 93.3%. The most frequent complications were transient neurological conditions (2.2%), hardware failure (1.9%), and transient pain (1.8%). The most frequent serious complications were nerve root injury (1.0%), gastrointestinal impairment (0.7%), and vertebral fractures (0.6%); (4) Conclusions: This is the first meta-analysis of the specific use of XLIF in spinal surgery. This study demonstrates that the XLIF technique in spine surgery is associated with good clinical and radiological results and a low complication rate.

Rapid (enhanced) recovery for fusion surgery in the degenerative spine: Clinical outcomes in 100 consecutive patients with a minimum 1-year follow-up

IntroductionSpinal surgical procedures became very frequent in the last decades with fusion techniques being widely used for several indications. Many of these surgeries imply a significant tissue disruption and muscle atrophy with subsequent pain and functional impairment. Research questionHow to prepare and manage patients according to a rapid/enhanced recovery (RR/ERAS) protocol in a private setting while improving patient’s peri-operative experience and minimizing surgical footprint? Material and methodsAll patients suffering from a thoracolumbar degenerative disease and with an indication for fusion between January 2018 and October 2021 were screened. Pain control, functional recovery, complication rate and patient’ satisfaction were recorded for at least one-year of follow-up (FU). Results100 patients were prospectively followed for at least one year after surgery. More than two thirds (n = 69, 69.0 %) had a trans-psoas extreme lateral interbody fusion (X-LIF) or anterior approach with posterior instrumentation and direct decompression when needed, 14 (14.0 %) had an anterior lumbar interbody fusion (ALIF) and 17 (17.0 %) patients had a posterior approach only (posterior LIF or transforaminal LIF). Most patients had multi-level surgery (n = 56, 56.0 %). All patients improved their quality of life and back and leg pain at one year FU with those having an antero-lateral approach improving significantly more. Overall satisfaction rate was higher than 90 %. Discussion and ConclusionThe application of RR/ERAS protocols to fusion surgery in degenerative spine proves to feasible and beneficial in a private care setting. Patients having anterolateral approaches tend to improve more than those with posterior only approaches.

Extreme Lateral Interbody Fusion: An Observational Study of Functional and Radiological Outcome

Introduction: Extreme lateral interbody fusion (XLIF) constitutes a minimally invasive procedure employed to address a spectrum of conditions including degenerative disc disorders, trauma, infections, and deformities. Despite its potential, there exists a scarcity of studies exploring perioperative functional and radiological outcomes. This prospective observational study seeks to address this gap by reporting these outcomes in patients treated at the King Faisal Specialist Hospital & Research Centre (KFSHRC) over a mean follow-up period of 5 years.
 Methods This case series amassed baseline patient data, encompassing gender, age, body mass index (BMI), American Society of Anesthesiology (ASA) classification, operated level, and posterior fixation type. Primary outcome measures encompassed the Oswestry Disability Index (ODI), Roland-Morris Disability Index (RMDI), Euro-Qol (EQ)-5D, visual analog scale (VAS), and EQ-5D index scores. Additionally, the study delved into secondary outcomes encompassing radiological parameters such as sagittal balance, lumbar lordosis, sacral slope, pelvic tilt, and pelvic incidence.
 Results: The study embraced 51 patients, comprising 9 females and 42 males, with a mean age of 58.6 years and a mean BMI of 29.3. The patients were followed for an average of 5.2 years. Stratification according to ASA classification revealed that 11.8% of patients were classified as ASA I, 52.9% as ASA II, and 35.3% as ASA III. The levels of operation included 60.8% at L4-L5, 33.3% at L3-L4, and 5.9% at L2-L3. The fixation techniques employed encompassed 58.8% bilateral and 41.2% unilateral approaches. The analysis of the primary clinical outcomes unveiled statistically significant enhancements in ODI, RMDI, EQ-5D VAS, and EQ-5D index scores. While lumbar lordosis registered a significant decrease, radiological parameters indicated non-significant shifts in pelvic incidence, pelvic tilt, and sacral slope.
 Conclusion The XLIF procedure emerges as an efficacious and minimally invasive avenue for managing degenerative disc disorders. The reported functional and radiological outcomes prove satisfactory. However, while demonstrably effective, the generation of clinical recommendations necessitates the compilation of results from randomized clinical trials.

Different lumbar fusion techniques for lumbar spinal stenosis: a Bayesian network meta-analysis

ObjectiveTo comprehensively compare and assess the effects of different lumbar fusion techniques in patients with lumbar spinal stenosis (LSS).MethodsPubMed, Embase, Cochrane Library, and Web of Science databases were systematically searched up to December 24, 2022 in this network meta-analysis. Outcomes were pain (pain, low back pain, and leg pain), Japanese Orthopaedic Association (JOA), Oswestry Disability Index (ODI), complications, reoperation, and fusion. Network plots illustrated the direct and indirect comparisons of different fusion techniques for the outcomes. League tables showed the comparisons of any two fusion techniques, based on both direct and indirect evidence. The efficacy of each fusion technique for LSS was ranked by rank probabilities.ResultsTotally 29 studies involving 2,379 patients were eligible. For pain, percutaneous endoscopic transforaminal lumbar interbody fusion (Endo-TLIF) was most likely to be the best technique, followed by minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), extreme lateral interbody fusion (XLIF), and transforaminal lumbar interbody fusion (TLIF). Percutaneous endoscopic posterior lumbar interbody fusion (Endo-PLIF) had the greatest likelihood to be the optimal technique for low back pain, followed sequentially by MIS-TLIF, minimally invasive posterior lumbar interbody fusion (MIS-PLIF), XLIF, Endo-TLIF, TLIF, oblique lumbar interbody fusion (OLIF), posterior lumbar interbody fusion (PLIF), and posterolateral lumbar fusion (PLF). MIS-PLIF was ranked the most effective technique concerning leg pain, followed by Endo-TLIF, MIS-TLIF, TLIF, Endo-PLIF, PLIF, OLIF, PLF, and XLIF. As regards JOA scores, Endo-TLIF had the maximum probability to be the best technique, followed by MIS-TLIF and TLIF. Endo-PLIF had the greatest likelihood to be the optimum technique for complications, followed by TLIF, MIS-TLIF, Endo-TLIF, OLIF, and XLIF.ConclusionMinimally invasive fusion techniques may be effective in the treatment of LSS, compared with traditional techniques. Minimally invasive techniques were likely non-inferior with regards to postoperative complications.

Cortical Endplate Bone Density Measured by Novel Phantomless Quantitative Computed Tomography May Predict Cage Subsidence more Conveniently and Accurately.

Previous studies have shown that bone mineral density (BMD) is a predictor of cage subsidence. Phantom-less quantitative computed tomography (PL-QCT) can measure volumetric bone mineral density (vBMD) of lumbar trabecular and cortical bone. The study of endplate vBMD (EP-vBMD) is important in predicting cage settlement after extreme lateral interbody fusion (XLIF). This study aimed to determine the risk factors for postoperative cage subsidence after XLIF, particularly focusing on the relationship between vBMD measured by automatic PL-QCT and cage subsidence. Patients who underwent XLIF surgery from January 2018 to October 2020 with a minimum of 6 months of follow-up were retrospectively included. Cage subsidence was defined as >2 mm cage sinking on the adjacent endplate in follow-up imaging evaluation. Outcome measures were localized vBMDs included EP-vBMDs with different region of interest (ROI) heights measured by PL-QCT based on a customized muscle-fat algorithm. Shapiro-Wilk test, one-way ANOVA, Mann-Whitney test, Fisher exact test, univariable and multivariable logistic regression and receiver operating characteristic (ROC) curve analysis were executed in this study. One hundred and thirteen levels of 78 patients were included in the analysis. The mean age was 65 ± 7.9 years for 11 males and 67 females. Cage subsidence occurred on 45 (39.8%) surgical levels. There was no significant difference in demographics, fused levels, or preoperative radiographic parameters. 1.25-mm EP-vBMD (0.991 [0.985,0.997], p = 0.004) and P-TB-vBMD (cage-positioned trabecular volumetric bone mineral density) (0.988 [0.977-0.999], p = 0.026) were cage-subsidence relevant according to univariate analysis. Low 1.25-mm EP-vBMD (0.992 [0.985, 0.999], p = 0.029) was an independent risk factor according to multifactorial analysis. Preoperative low EP-vBMD was an independent risk factor for postoperative cage subsidence after XLIF. EP-vBMD measured by most cortex-occupied ROI may be the optimal vBMD parameter for cage subsidence prediction.

Risk factors of postoperative coronal malalignment following long-segment spinal fusion surgery in which multilevel lateral lumbar interbody fusion was used for degenerative lumbar kyphoscoliosis.

In patients with adult spinal deformity, especially degenerative lumbar kyphoscoliosis (DLKS), preoperative sagittal malalignment and coronal malalignment (CM) often coexist. Lateral lumbar interbody fusion (LLIF) has recently been widely chosen for DLKS treatment due to its minimal invasiveness and excellent sagittal alignment correction. However, postoperative CM may remain or occur due to an oblique takeoff phenomenon following multilevel LLIF, resulting in poor clinical outcomes. The authors investigated the risk factors for postoperative CM after long-segment fusion corrective surgery in which multilevel LLIF was used in patients with DLKS. Fifty-four consecutive patients with DLKS, main Cobb angle ≥ 20°, and lumbar lordosis ≤ 20° who underwent corrective spinal fusion surgery, including extreme lateral interbody fusion at ≥ 3 segments, were included at the authors' institute between April 2014 and October 2019. Patients who underwent suitable 3-column osteotomy, classified as grade 3-6 per the Scoliosis Research Society-Schwab criteria, were excluded. Patients were divided into CM and non-CM groups based on postoperative CM evaluated using standard standing-position radiographs obtained 2 years postoperatively. CM was defined as an absolute C7-CSVL (deviation of C7 plumb line off central sacral vertical line; calculated by defining the convex side of the CSVL as positive numerical values) value of ≥ 3.0 cm. Patient demographics and preoperative sagittal alignment parameters were evaluated. The following variables were measured to assess coronal alignment: main Cobb angle; preoperative C7-CSVL; amount of lateral listhesis; L4, L5, and sacral coronal tilt angles; coronal vertebral deformity angles; and coronal spine rigidity. Regarding risk factors for postoperative CM, patient characteristics, preoperative sagittal parameters, and coronal parameters did not significantly differ between the 2 groups, except for preoperative C7-CSVL (p = 0.016). Multivariate logistic regression analysis revealed that preoperative C7-CSVL (+1 cm; OR 1.23, 95% CI 1.05-1.50; p = 0.007) was a significant predictor of postoperative CM. Receiver operating characteristic curve analysis demonstrated that the cutoff value for preoperative C7-CSVL was +0.3 cm, the sensitivity was 85.7%, the specificity was 60.6%, and the area under the curve was 0.70. In corrective fusion surgery for DLKS in which multilevel LLIF was used, the occurrence of postoperative CM was associated with preoperative C7-CSVL. According to the C7-CSVL, which was evaluated by defining the convex side of the CSVL as positive numerical values and the concave side as negative numerical values, the CM group had a significantly higher value of preoperative C7-CSVL than did the non-CM group. Alternative corrective fusion methods, other than multiple LLIFs, may be considered in DLKS cases with a C7-CSVL of +0.3 cm or greater.

Unique Characteristics of New Bone Formation Induced by Lateral Lumbar Interbody Fusion Procedure.

Despite the absence of bone grafting in the area outside the cage, lateral bridging callus outside cages (LBC) formation is often observed here following extreme lateral interbody fusion (XLIF) conversely to conventional methods of transforaminal lumbar interbody fusion and posterior lumbar interbody fusion. The LBC, which may increase stabilization and decrease nonunion rate in treated segments, has rarely been described. This study aimed to identify the incidence and associated factors of LBC following XLIF. We enrolled 136 consecutive patients [56 males, 80 females; mean age 69.6 (42-85) years] who underwent lumbar fusion surgery using XLIF, including L4/5 level with posterior fixation at a single institution between February 2013 and February 2018. One year postoperatively, the treated L4/5 segments were divided into the LBC formation and non-formation groups. Potential influential factors, such as age, sex, body mass index, bone density, height of cages, cage material (titanium or polyetheretherketone [PEEK]), presence or absence of diffuse idiopathic skeletal hyperostosis (DISH), and radiological parameters, were evaluated. Multivariate logistic regression analysis was performed for factors significantly different from the univariate analysis. The incidence of LBC formation was 58.8%. Multivariate logistic regression analysis showed that the length of osteophytes [+1 mm; odds ratio, 1.29; 95% confidence interval, 1.17-1.45; p<0.0001] was significant LBC formation predictive factors. Receiver operating characteristic curve analysis demonstrated that the cut-off value for osteophyte length was 14 mm, the sensitivity was 58.8%, the specificity was 84.4%, and the area under the ROC curve for this model was 0.79. The incidence of LBC formation was 58.8% in L4/5 levels one year after the XLIF procedure. We demonstrated that the length of the osteophyte was significantly associated with LBC formation.

Perspective; high frequency of intraoperative errors due to extreme, oblique, and lateral lumbar interbody fusions (XLIF, OLIF, LLIF): Are they "safe"?

Extreme Lateral Lumbar Interbody Fusions (XLIF), Oblique Lateral Interbody Fusion (OLIF,) and Lateral Lumbar Interbody Fusion (LLIF) were largely developed to provide indirect lumbar decompressions for spinal stenosis, deformity, and/or instability. Here, we have reviewed and updated the incidence of intraoperative errors attributed to XLIF, OLIF, and LLIF. Specifically, we focused on how often these procedures caused new neurological deficits, major vessel, visceral, and other injuries, including those warranting secondary surgery. Performing XLIF, OLIF, and LLIF can lead to significant intraoperative surgical errors that include varying rates of; new neurological injuries (i.e. iliopsoas motor deficits (4.3-19.7-33.6-40%), proximal hip/upper thigh sensory loss/dysesthesias (5.1% to 21.7% to 40%)), life-threatneing vascular injuries (i.e., XLIF (0% - 0.4%-1.8%), OLIF (3.2%), and LLIF (2%) involving the aorta, iliac artery, inferior vena cava, iliac vein, and segmental arteries), and bowel/viscarl injuries (0.03%-0.4%) leading to reoperations (i.e., XLIF (1.8%) vs. LLIF (3.8%) vs. XLIF/LLIF/OLIF 2.2%)). Varying reports documented that XLIF, OLIF and LLIF caused up to a 40% incidence of new sensory/motor deficits, up to a 3.2% incidence of major vascular insults, a 0.4% frequency of visceral/bowel perforations, and a 3.8% need for reoperations. These high frequencies of intraoperative surgical errors attributed to XLIF, OLIF, and LLIF should prompt reconsideration of whether these procedures are "safe."

INVESTIGATION OF BACTERIAL AND VIRAL SLOW INTERVERTEBRAL DISC INFECTIONS

Objective. Currently, few publications have been available regarding an effect of level, type of intrusion, and viral infections on spinal disc degeneration. The study was aimed to evaluate an incidence of indolent bacterial and viral intervertebral disc infections in unstratified group of patients operated on for spinal degenerative pathologies.&#x0D; Material and methods. For the study, intraoperative disc samples were collected from patients who underwent discectomy and total spinal fusion surgery for degenerative pathologies between the years December, 2018 to January, 2020. 447 samples were examined obtained from 392 patients (189 women and 203 men) with a mean age of 58.1 years.&#x0D; The following epidemiological and clinical data were collected: gender, age, spinal segments affected, type of surgical approach, preoperative C-reactive protein (CRP; reference range 0.00.5 mg/dL), and preoperative as well as 6-month postoperative ODI and NDI, both expressed as a percentage. The incidence of postoperative infections within six months after surgery as well as MI for each operated segment was assessed. Only patients with ventral cervical or dorsal thoracic access were enrolled in the study. In the lumbar region, the ventral assess was chosen for anterior lumbar interbody fusion, the lateral approach for oblique or extreme lateral interbody fusion, and the dorsal approach in case of standard microdiscectomy of posterior transforaminal interbody fusion or transforaminal interbody fusion.&#x0D; A logistic regression analysis was performed to model a risk of positive microbiological culture and a risk of emerging modal changes by using a set of independent variables selected in a stepwise manner by using the Akaike information criterion as a measure of quality of select procedure.&#x0D; Results. MRI for modal analysis was available for all 447 segments. MRI revealed 45 type 1 SCs (10.07% of all segments), 118 type 2 SCs (26.4%), and 5 type 3 SCs (1.12%). Microbiological culture was available in 410 segments. In these 410 segments, 39 type 1 MCs, 113 type 2 MCs, and 5 type 3 MCs were found. A statistically significant relationship was found between SC type 2 and a positive microbiological result (p = 0.0127). In contrast, there were no statistically significant associations for type 1 and type 3 SCs (p=0.3052 and p=0.0767, respectively).&#x0D; Conclusion. A relation between disc degeneration and infections seems unlikely. Histopathological evidence of inflammation in degenerated discs is rare and unrelated to microbiological findings.

Comparison of PLIF/TLIF and LLIF for two-level degenerative lumbar spondylolisthesis

IntroductionIn recent years, lateral lumbar interbody fusion (LLIF), performed as extreme lateral interbody fusion (XLIF) and oblique lateral interbody fusion (OLIF), has also become widely used for anterior-posterior corrective fusion. However, there are few detailed reports comparing techniques in the treatment of two-level degenerative spondylolisthesis. We compared the surgical invasiveness and postoperative outcomes between posterior interbody fusion with posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF) and LLIF for two-level lumbar degenerative spondylolisthesis. MethodsFifteen patients underwent PLIF or TLIF at 2 vertebral intervals (posterior group) and 8 patients received XLIF or OLIF (LLIF group). The following parameters were examined: operative time, blood loss, preoperative %slip, preoperative sagittal parameters, postoperative %slip, postoperative 1-year %slip, postoperative 1-year sagittal parameters, bone fusion rate at 1 year postoperatively, pre- and postoperative visual analog scale scores, pre- and postoperative Japanese Orthopaedic Association (JOA) scores, and complications. ResultsIn the LLIF group, blood loss was significantly lower and operative time was shorter than in the posterior group. There were no significant differences for 1-year postoperative %slip, sagittal vertical axis, or lumbar lordosis, although the frequency of cases with a 1-year postoperative pelvic incidence (PI)-LL ≤ 10 degrees was significantly higher in the LLIF group. In both groups, JOA scores were improved significantly at 1 year postoperatively (both p < 0.01), with no remarkable difference in improvement rate between the groups (p = 0.09). ConclusionsLLIF was less invasive, comparably effective, and more preserving of global spinal balance in correcting two-level degenerative spondylolisthesis than conventional posterior interbody fusion.

Elimination of Lumbar Plexus Injury by Changing the Entry Point and Traction Direction of the Psoas Major Muscle in Transpsoas Lateral Lumbar Spine Surgery.

Background and Objectives: The lateral approach is commonly used for anterior column reconstruction, indirect decompression, and fusion in patients with lumbar degenerative diseases and spinal deformities. However, intraoperative lumbar plexus injury may occur. This is a retrospective comparative study to investigate and compare neurological complications between the conventional lateral approach and a modified lateral approach at L4/5. Materials and Methods: Patients with a lumbar degenerative disease requiring single-level intervertebral fusion at L4/5 were included and categorized into group X and group A. Patients in group X underwent conventional extreme lateral interbody fusion, while those in group A underwent a modified surgical procedure that included splitting of the anterior third of the psoas muscle, which was dilated by the retractor on the anterior third of the intervertebral disc. The incidence of lumbar plexus injury, defined as a decrease of ≥1 grade on manual muscle testing of hip flexors and knee extensors and sensory impairment of the thigh for ≥3 weeks, on the approach side, was investigated. Results: Each group comprised 50 patients. No significant between-group differences in age, sex, body mass index, and approach side were observed. There was a significant between-group difference in intraoperative neuromonitoring stimulation value (13.1 ± 5.4 mA in group X vs. 18.5 ± 2.3 mA in group A, p < 0.001). The incidence of neurological complications was significantly higher in group X than in group A (10.0% vs. 0.0%, respectively, p < 0.05). Conclusions: In our modified procedure, the anterior third of the psoas muscle was entered and split, and the intervertebral disc could be reached without damaging the lumbar plexus. When performing lumbar surgery using the lateral approach, lumbar plexus injury can be avoided by following surgical indication criteria based on the location of the lumbar plexus with respect to the psoas muscle and changing the transpsoas approach to the intervertebral disc.

Vertebral Endplate Concavity in Lateral Lumbar Interbody Fusion: Tapered 3D-Printed Porous Titanium Cage versus Squared PEEK Cage

Background and Objectives: To prevent postoperative problems in extreme lateral interbody fusion (XLIF), it is critical that the vertebral endplate not be injured. Unintentional endplate injuries may depend on the cage. A novel porous titanium cage for XLIF has improved geometry with a tapered tip and smooth surface. We hypothesized that this new cage should lead to fewer endplate injuries. Materials and Methods: This retrospective study included 32 patients (mean 74.1 ± 6.7 years, 22 females) who underwent anterior and posterior combined surgery with XLIF for lumbar degenerative disease or adult spinal deformity from January 2018 to June 2022. A tapered 3D porous titanium cage (3DTi; 11 patients) and a squared PEEK cage (sPEEK; 21 patients) were used. Spinal alignment values were measured on X-ray images. Vertebral endplate concavity (VEC) was defined as concavity ≥ 1 mm of the endplate on computed tomography (CT) images, which were evaluated preoperatively and at 1 week and 3 months postoperatively. Results: There were no significant differences in the patient demographic data and preoperative and 3-month postoperative spinal alignments between the groups. A 3DTi was used for 25 levels and an sPEEK was used for 38 levels. Preoperative local lordotic angles were 4.3° for 3DTi vs. 4.7° for sPEEK (p = 0.90), which were corrected to 12.3° and 9.1° (p = 0.029), respectively. At 3 months postoperatively, the angles were 11.6° for 3DTi and 8.2° for sPEEK (p = 0.013). VEC was present in 2 levels (8.0%) for 3DTi vs. 17 levels (45%) for sPEEK (p = 0.002). After 3 months postoperatively, none of the 3DTi had VEC progression; however, eight (21%) levels in sPEEK showed VEC progression (p = 0.019). Conclusions: The novel 3DTi cage reduced endplate injuries by reducing the endplate load during cage insertion.

Anterior Longitudinal Ligament Avulsion Fracture when Changing the Patient's Position from Lateral to Prone during Extreme Lateral Interbody Fusion: A Case Report.

Anterior Longitudinal Ligament Avulsion Fracture when Changing the Patient's Position from Lateral to Prone during Extreme Lateral Interbody Fusion: A Case Report.

A biomechanical comparison of posterior fixation approaches in lumbar fusion using computed tomography based lumbosacral spine modelling

Extreme lateral interbody fusion (XLIF) may be performed with a standalone interbody cage, or with the addition of unilateral or bilateral pedicle screws; however, decisions regarding supplemental fixation are predominantly based on clinical indicators. This study examines the impact of posterior supplemental fixation on facet micromotions, cage loads and load-patterns at adjacent levels in a L4-L5 XLIF at early and late fusion stages. CT data from an asymptomatic subject were segmented into anatomical regions and digitally stitched into a surface mesh of the lumbosacral spine (L1-S1). The interbody cage and posterior instrumentation (unilateral and bilateral) were inserted at L4-L5. The volumetric mesh was imported into finite element software for pre-processing, running nonlinear static solves and post-processing. Loads and micromotions at the index-level facets reduced commensurately with the extent of posterior fixation accompanying the XLIF, while load-pattern changes observed at adjacent facets may be anatomically dependent. In flexion at partial fusion, compressive stress on the cage reduced by 54% and 72% in unilateral and bilateral models respectively; in extension the reductions were 58% and 75% compared to standalone XLIF. A similar pattern was observed at full fusion. Unilateral fixation provided similar stability compared to bilateral, however there was a reduction in cage stress-risers with the bilateral instrumentation. No changes were found at adjacent discs. Posterior supplemental fixation alters biomechanics at the index and adjacent levels in a manner that warrants consideration alongside clinical information. Unilateral instrumentation is a more efficient option where the stability requirements and subsidence risk are not excessive.

Extreme Lateral Interbody Fusion (XLIF) with Lateral Modular Plate Fixation: Preliminary Report on Clinical and Radiological Outcomes.

The lateral transpsoas approach (extreme lateral interbody fusion, or XLIF) allows surgeons to use various lordotic cage sizes to help restore intervertebral disk height, correct sagittal alignment, and improve fusion rates. The use of standalone devices has consistently raised doubts due to the high risk of complications and inadequate functional recovery that a circumferential arthrodesis can support. The recent introduction of a novel XLIF cage with adapted lateral plate fixation (XLPF) may further enhance the structural rigidity, consolidating the cage and plate into a singular modular entity. Nine patients from our surgical centers underwent a procedure of 1-level XLIF with XLPF in selected cases. We observed that XLPF does not extend the intraoperative footprint and provides immediate rigidity to the anterior column without any additional risk of complications and with minimal increased time compared to the traditional cage implant procedure. Although it has been shown that the use of interbody fusion cages with supplemental posterior fixation improves stabilization in all directions, the technique of standalone lateral cages may also have a place in spine surgery in that the stability may be sufficient in selected cases, such as junctional syndrome and in some forms of degenerative scoliosis.

Minimally Invasive Transforaminal Lumbar Interbody Fusion (MI-TLIF): A Video Technique Guide.

Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) has been established as an excellent alternative to the traditional open approach for the treatment of degenerative conditions of the lumbar spine1-3. The procedure is performed with the patient under general anesthesia and on a radiolucent table in order to allow for intraoperative fluoroscopy. The procedure is performed through small incisions made over the vertebral levels of interest, typically utilizing either a fixed or expandable type of tubular dilator, which is eventually seated against the facet joint complex4. A laminectomy and/or facetectomy is performed in order to expose the disc space, and the ipsilateral neural elements are visualized5. The end plates are prepared, and an interbody device is placed after the disc is removed. Pedicle screws and rods are then placed for posterior fixation. Nonoperative alternatives include physical therapy and corticosteroid injections. Other operative techniques include open TLIF or other types of lumbar fusion approaches, such as posterior lumbar interbody fusion (PLIF), anterior lumbar interbody fusion, lateral or extreme lateral interbody fusion, or oblique lumbar interbody fusion. Open TLIF was developed in order to obtain a more lateral approach to the lumbar disc space than was previously possible with PLIF. The goal of this was to minimize the amount of thecal-sac and nerve-root retraction required during PLIF4. Additionally, as the number of patients who required revision after PLIF increased, the need arose for an approach to the lumbar spine that circumvented the posterior midline scarring from previous PLIF surgical sites6. MI-TLIF was introduced to reduce the approach-related paraspinal muscle damage of open TLIF5. Indications for MI-TLIF include most degenerative pathology of the lumbar spine, including disc herniation, low-grade spondylolisthesis, and spinal and foraminal stenosis7. However, MI-TLIF allows for less robust correction of deformity than other minimally invasive approaches; therefore, MI-TLIF may not be as effective in cases of substantial spinal deformity or high-grade spondylolisthesis8. MI-TLIF results in significantly less blood loss, postoperative pain, and hospital length of stay compared with open TLIF1-3. Although some studies have suggested increased operative time for MI-TLIF9,10, meta-analyses have shown comparable operative times between the 2 techniques1-3. It is thought that the discrepancy in reported operative times is the result of a learning curve and that, once that is overcome, the difference in operative time between the 2 techniques becomes minimal11,12. One disadvantage of MI-TLIF that has remained constant in the literature is its increased intraoperative fluoroscopy time compared with open TLIF3,13. The complication rate has largely been found to be equivalent between open and MI-TLIF1-3 or slightly lower with MI-TLIF14, especially in the hands of an experienced surgeon15. Finally, the fusion rate and improvement in patient outcome scores have also been found to be largely equivalent1-3. We suggest placing the ipsilateral pedicle screw after the interbody cage has been inserted.Fully visualize the Kambin triangle16 prior to performing the facetectomy. Protect the exiting and traversing nerve roots by placing small cottonoids around them and retracting delicately.Bone removed during facetectomy can be utilized as autograft for the interbody cage.Avoid removing pedicle bone during decompression.If central stenosis is present, the neural decompression should be extended medial to the epidural fat so that the dura mater can be visualized all of the way to the contralateral pedicle.Perform an adequate end plate preparation prior to interbody insertion while being mindful to avoid injuring the end plate, to minimize the risk of future cage subsidence.Confirm correct placement of the interbody device on intraoperative fluoroscopy.If bone morphogenic protein is utilized, be careful not to pack too much posteriorly as this may cause nerve irritation. TLIF = transforaminal lumbar interbody fusionMI-TLIF = minimally invasive TLIFPLIF = posterior lumbar interbody fusionALIF = anterior lumbar interbody fusionLLIF = lateral lumbar interbody fusionXLIF = extreme lateral interbody fusionOLIF = oblique lumbar interbody fusionDLIF = direct lateral interbody fusionMRI = magnetic resonance imagingA/P = anteroposteriorEMG = electromyographicBMP = bone morphogenic proteinXR = x-ray (radiograph)OTC = over the counterDVT = deep vein thrombosisPE = pulmonary embolismMI = myocardial infarctionMIS = minimally invasive surgeryOR = operating roomLOS = length of stayVAS = visual analog scaleODI = Oswestry Disability IndexM-H = Mantel-HaenszelRR = risk ratioCI = confidence intervalNSAIDs = nonsteroidal anti-inflammatory drugs.