Is Direct Decompression Necessary for Lateral Lumbar Interbody Fusion (LLIF)? A Randomized Controlled Trial Comparing Direct and Indirect Decompression With LLIF in Selected Patients.

OBJECTIVE: To compare the clinical and radiographic outcomes following lateral lumbar interbody fusion (LLIF) between direct and indirect decompression in the treatment of patients with degenerative lumbar diseases. METHODS: Patients who underwent single-level LLIF were randomized into 2 groups: direct decompression (group D) and indirect decompression (group I). Clinical outcomes including the Oswestry Disability index and visual analogue scale of back and leg pain were collected. Radiographic outcomes including cross-sectional area (CSA) of thecal sac, disc height, foraminal height, foraminal area, fusion rate, segmental, and lumbar lordosis were measured. RESULTS: Twenty-eight patients who met the inclusion criteria were eligible for the analysis, with a distribution of 14 subjects in each group. The average age was 66.1 years. Postoperatively, significant improvements were observed in all clinical parameters. However, these improvements did not show significant difference between both groups at all follow-up periods. All radiographic outcomes were not different between both groups, except for the increase in CSA which was significantly greater in group D (77.73 ± 20.26 mm2 vs. 54.32 ± 35.70 mm2, p = 0.042). Group I demonstrated significantly lower blood loss (68.13 ± 32.06 mL vs. 210.00 ± 110.05 mL, p < 0.005), as well as shorter operative time (136.35 ± 28.07 minutes vs. 182.18 ± 42.67 minutes, p = 0.002). Overall complication rate was not different. CONCLUSION: Indirect decompression through LLIF results in comparable clinical improvement to LLIF with additional direct decompression over 1-year follow-up period. These findings suggest that, for an appropriate candidate, direct decompression in LLIF might not be necessary since the ligamentotaxis effect achieved through indirect decompression appears sufficient to relieve symptoms while diminishing blood loss and operative time.

Should a Narrow Corridor Be a Contraindication for Performing Oblique Lateral Interbody Fusion Procedure or Not?

STUDY DESIGN: Retrospective study. OBJECTIVES: We investigated the effect of corridor width on the postoperative outcomes of patients who underwent the OLIF procedure. METHODS: Patients who underwent OLIF surgery, which included L4-5, between 2015 and 2021 were retrospectively studied. The patients were divided into three groups by the width of the corridor: not more than 10 mm, between 10 and 20 mm, and 20 mm or more. We compared clinical and radiographic outcomes and complications between these groups. RESULTS: A total of 81 patients were included. There were no significant differences in VAS leg and back pain scores, ODI scores, or complications between each group. The radiographic findings, including cage position, anterior and posterior disc height, segmental Cobb angle, and foraminal height, also showed no significant differences between each group. The only radiographic finding that showed a significant difference between each group was the angle of the cage. We found significantly less degree of angle in the wider than 20 mm group when compared to the other two groups. (P-value = .01). There was no recorded incidence of major vascular complications. CONCLUSIONS: The width of oblique corridor does not affect clinical outcomes, complications, or radiographic findings, including position of the cage, anterior and posterior disc height, segmental angle, and foraminal height after OLIF procedure, including L4-5 level. Thus, the OLIF procedure can be performed safely even in patients with limited oblique corridors, especially at L4-5.

The Role and Clinical Outcomes of Endoscopic Spine Surgery of Treating Spinal Metastases; Outcomes of 29 Cases From 8 Countries.

OBJECTIVE: We aim to report the outcomes and feasibility of endoscopic spine surgery used to treat symptomatic spinal metastases patients. This is the most extensive series of spinal metastases patients who underwent endoscopic spine surgery. METHODS: A worldwide collaborative network group of endoscopic spine surgeons, named 'ESSSORG,' was established. Patients diagnosed with spinal metastases who underwent endoscopic spine surgery from 2012 to 2022 were retrospectively reviewed. All related patient data and clinical outcomes were gathered and analyzed before the surgery and the followtime period of 2 weeks, 1 month, 3 months, and 6 months. RESULTS: A total of 29 patients from South Korea, Thailand, Taiwan, Mexico, Brazil, Argentina, Chile, and India, were included. The mean age was 59.59 years, and 11 of them were female. The total number of decompressed levels was 40. The technique was relatively equal (15 uniportal; 14 biportal). The average length of admission was 4.41 days. Of all patients with an American Spinal Injury Association Impairment Scale of D or lower before surgery, 62.06% reported having at least one recovery grade after the surgery. Almost all clinical outcomes parameters statistically significantly improved and maintained from 2 weeks to 6 months after the surgery. Few surgical-related complications (4 cases) were reported. CONCLUSION: Endoscopic spine surgery is a valid option for treating spinal metastases patients as it could yield comparable results to other minimally invasive spine surgery techniques. As the aim is to improve the quality of life, this procedure is valuable and holds value in palliative oncologic spine surgery.

Pan-cancer analysis of the intervertebral-disc-degeneration-related innate immunity gene NAIP.

BACKGROUND: Intervertebral disc degeneration (IDD) is a progressive chronic condition that commonly causes low back pain. Cancer is among the primary reasons for deaths worldwide. Our purpose was to identify the characteristic genes of IDD and explore the potential association between IDD and cancer. METHODS: Immune cell infiltration and differentially expressed analysis were conducted utilizing data from the GSE124272 database. Enrichment analysis of differentially expressed genes (DEGs) was performed to explore the possible mechanisms underlying IDD development. Moreover, weighted gene correlation network analysis (WGCNA) was applied to select IDD-related hub genes. The immune-related key genes were determined by intersecting DEGs, IDD-related hub genes, and immune genes. Subsequently, machine learning models based on these genes were built to identify and verify the characteristic genes. RNA sequencing and clinical data of 33 carcinoma categories were obtained from the Cancer Genome Atlas (TCGA). The association between NAIP expression and prognosis was calculated using the Kaplan-Meier analysis. To gain a deeper understanding of the impact of NAIP in tumor immunotherapy, the association between NAIP and immune infiltration and two immunotherapeutic biomarkers were explored. Ultimately, the association between NAIP and immunotherapeutic response was investigated utilizing two independent cohorts. RESULTS: NAIP was identified as an immune-related characteristic gene between IDD and normal intervertebral disc tissue. In certain carcinoma categories, NAIP expression levels were elevated (4/33) and significantly correlated to the respective tumor stage (4/21). Survival analysis revealed that the expression levels of NAIP have prognostic significance in different cancer types. Generally, NAIP presented a strong association with immune cell infiltration and modulators. NAIP may influence immunotherapy effects through tumor mutational burden and microsatellite instability. No remarkable association between NAIP and immunotherapy response was found in either cohort. CONCLUSION: Our study is the first to identify NAIP as an immune-related characteristic gene. Pan-cancer analysis revealed that NAIP could serve as a novel clinical prognostic marker and therapeutic target for a variety of carcinoma categories, reducing the risk of IDD in tumor patients.

Comparing Efficacy of Lumbar Disc Space Preparation via an Anterior-to-Psoas Approach Between Intraoperative Conventional Fluoroscopy and Computed Tomographic-Based Navigation System: A Cadaveric Study.

OBJECTIVE: To compare the efficacy of intervertebral disc space preparation via an anterior-to-psoas (ATP) approach using conventional fluoroscopy (Flu) and computer tomography (CT)-based navigation by evaluating the disc remaining area. METHODS: We equally assigned 24 lumbar disc levels from 6 cadavers into Flu and CT-based navigation (Nav) groups. Two surgeons performed disc space preparation using the ATP approach in both groups. Digital images of each vertebral endplate were obtained, and the remaining disc tissue was calculated in total and in quadrants. Operative time, number of attempts at disc removal, endplate violation area, number of endplate violation segments, and access angle were recorded. RESULTS: The overall percentage of remaining disc tissue was significantly less in the Nav group than in the Flu group (32.7% vs. 43.3% respectively, P < 0.001). A significant difference was found in the posterior-ipsilateral (4.2% vs. 7.1%, P = 0.005) and posterior-contralateral (6.1% vs. 10.9%, P = 0.002) quadrants, respectively. No significant between-group difference was found concerning operative time, number of attempts at disc removal, endplate violation area, number of endplate violation segments, or access angle. CONCLUSIONS: Intraoperative CT-based navigation may improve vertebral endplate preparation quality for an ATP approach, especially in the posterior quadrants. This technique may offer an effective alternative disc space and endplate preparation methods and may help enhance the fusion rates.

"Platelet-Rich Plasma" epidural injection an emerging strategy in lumbar disc herniation: a Randomized Controlled Trial.

BACKGROUND: Lumbar herniated disc (HNP) is mainly treated by conservative management. Epidural steroid injection (ESI) has been an option to treat failed cases prior to surgery. Triamcinolone has been widely used due to its efficacy in bringing about pain reduction for up to three months. However, several reports have shown some severe adverse events. Platelet-rich plasma (PRP) is made from blood through centrifugation. Several studies supported the potential short to long-term effects, and safety of PRP injection in treating HNP. The study objective was to evaluate the efficacy of PRP in treatment of single-level lumbar HNP in comparison to triamcinolone. METHODS: Thirty patients were treated by transforaminal epidural injections. PRP was obtained from 24 ml venous blood through standardized double-spin protocol. Participants included fifteen patients each being in triamcinolone and PRP groups. The same postoperative protocols and medications were applied. The visual analogue scale of leg (LegVAS), collected at baseline, 2, 6, 12, and 24 weeks, was the primary outcome. The BackVAS, Oswestry Disability Index (ODI), adverse event, and treatment failure were the secondary endpoints. RESULTS: Platelet ratio of PRP in fifteen patients was 2.86 ± 0.85. Patients treated by PRP injections showed statistically and clinically significant reduction in LegVAS at 6, 12, and 24 weeks, and in ODI at 24 weeks. It demonstrated comparable results on other aspects. No adverse event occurred in either group. CONCLUSION: Noncommercial epidural double-spin PRP yielded superior results to triamcinolone. Due to its efficacy and safety, the procedure is recommended in treating single level lumbar HNP. TRIAL REGISTRATION: NCT, NCT05234840. Registered 1 January 2019, https://clinicaltrials.gov/ct2/show/record/NCT05234840 .

A 30-Year Worldwide Research Productivity of Scientific Publication in Full-Endoscopic Decompression Spine Surgery: Quantitative and Qualitative Analysis.

OBJECTIVE: The ever-growing number of articles related to full-endoscopic spine surgery published in the last few decades presents a challenge which is perplexing and time-consuming in identifying the current research status. The study aims to identify and analyze the most cited works related to full-endoscopic decompression spine surgery, compare the articles published by different publishers and area, and show the current publication status of full-endoscopic research. METHODS: Using Bibliometrix, CiteSpace, and VOSviewer, we analyzed the bibliometric data selected from the Web of Science database between 1992 and 2022. Spine has the highest H-index with the most-cited journal in the field of full-endoscopic decompression spine surgery. China ranked as the most productive country, whereas the most cited with high H-index papers came from South Korea. For the author analysis, Yeung AT, Ruetten S, Hoogland T, Ahn Y, Choi G, and Mayer HM were the most impactful authors in the global and local citations. The most productive organization is Wooridul Spine Hospital. CONCLUSION: The bibliometric study showed a growing trend of research on full-endoscopic decompression spine surgery over the past 30 years. It has demonstrated that there is a significant increase in the number of authors, institutions, and internationally collaborated countries. However, the quality of studies is still low, and the lack of high-quality clinical evidence and the trend of general journal submissions has somewhat affected the quality of endoscopy journals in recent years.

Comparison of full-endoscopic and tubular-based microscopic decompression in patients with lumbar spinal stenosis: a randomized controlled trial.

PURPOSE: We aimed to demonstrate non-inferiority in terms of functional outcomes in patients with lumbar spinal stenosis who underwent full-endoscopic decompression compared with tubular-based microscopic decompression. METHODS: This prospective, randomized controlled, non-inferiority trial included 60 patients with single-level lumbar spinal stenosis who required decompression surgery. The patients were randomly assigned in a 1:1 ratio to the full-endoscopic group (FE group) or the tubular-based microscopic group (TM group). Based on intention-to-treat analysis, the primary outcome was the Oswestry Disability Index score at 24 months postoperative. The secondary outcomes included the visual analog scale (VAS) score for back and leg pain, European Quality of Life-5 Dimensions (EQ-5D) score, walking time, and patient satisfaction rate according to the modified MacNab criteria. Surgery-related outcomes were also analyzed. RESULTS: Of the total patients, 92% (n = 55) completed a 24-month follow-up. The primary outcomes were comparable between the two groups (p = 0.748). However, the FE group showed a statistically significant improvement in the mean VAS score for back pain at day 1 and at 6, 12, and 24 months after surgery (p < 0.05). No significant difference was observed in the VAS score for leg pain, EQ-5D score, or walking time (p > 0.05). Regarding the modified MacNab criteria, 86.7% of patients in the FE group and 83.3% in the TM group had excellent or good results at 24 months after surgery (p = 0.261). Despite the similar results in surgery-related outcomes, including operative time, radiation exposure, revision rate, and complication rate, between the two groups (p > 0.05), less blood loss and shorter length of hospital stay were observed in the FE group (p ≤ 0.001 and 0.011, respectively). CONCLUSION: This study suggests that full-endoscopic decompression is an alternative treatment for patients with lumbar spinal stenosis because it provides non-inferior clinical efficacy and safety compared with tubular-based microscopic surgery. In addition, it offers advantages in terms of less invasive surgery. Trial registration number (TRN): TCTR20191217001.

Endoscopic anterior to psoas lumbar interbody fusion: indications, techniques, and clinical outcomes.

PURPOSE: The retrospective study aimed to report the surgical technique and clinic-radiological outcomes of endoscopic anterior to psoas interbody lumbar fusion through the retroperitoneal approach with direct and indirect decompression. METHODS: We retrospectively analyzed the results of clinical parameters of patients who underwent endoscopic anterior to psoas interbody lumbar fusion between June 2013 and June 2022. Clinical outcomes were evaluated by the visual analog scale (VAS) and Oswestry Disability Index (ODI) scores. The radiological outcomes were measured and statistically compared in disc height index (DHI), whole lumbar lordosis (WLL), pelvic Incidence (PI), pelvic tilt (PT), Segmental lordosis (SL), the sagittal vertical axis (SVA). RESULTS: A total of 35 patients were selected for the procedure ranging in age from 51 to 84 years with 17.83 ± 8.85 months follow-up. The mean operation time in lateral position for one level was 162.96 ± 35.76 min (n = 24), and 207.73 ± 66.60 min for two-level fusion. The mean endoscopic time was 32.83 ± 17.71 min per level, with a total estimated blood loss of 230.57 ± 187.22 cc. The mean postoperative VAS back, leg pain score and ODI improved significantly compared to the preoperative values; Radiological data showed significant change in WLL, SL, DHI, PI, PT, and SS; however, there is no significant difference in SVA postoperatively. Subgroup analysis for the radiographic data showed 50 mm length cage has significantly improved for the DHI, SS and SVA compare to 40 mm length cage. The subgroup analysis results showed that hypertensive patients had significantly higher proportion in the incomplete fusion group compare to complete fusion group at one-year follow-up. OUTCOMES: The endoscopic anterior to psoas interbody lumbar fusion achieves satisfactory indirect and direct decompression. This convergent technique presents an effective choice for treating lumbar instability associated with disc herniations and foraminal stenosis, thus complementing the indications for oblique lumbar interbody fusion.

Factors associated with incomplete clinical improvement in patients undergoing transforaminal endoscopic lumbar discectomy for lumbar disc herniation.

PURPOSES: To analyze the clinical and radiographic risk factors that might predict incomplete clinical improvement after transforaminal endoscopic lumbar discectomy (TELD). METHODS: A retrospective analysis was conducted from 194 consecutive patients who underwent TELD due to lumbar disc herniation (LDH). Patients with incomplete clinical improvement were defined from patient-reported outcomes of poor improvement in pain or disability after surgery and patient dissatisfaction. Clinical and radiographic characteristics were evaluated to identify predicting factors of poor outcomes. RESULTS: Of 194 patients who underwent TELD procedures, 32 patients (16.5%) had incomplete clinical improvement and 12 patients (6.1%) required revision surgery. The mean ages were 46.4 years and most of the patients suffered from predominant leg pain (48.9%). The most common surgical level was L4-5 (63.9%). Overall, the Oswestry Disability Index (44.3-15), visual analog scores of back pain (4.9-1.8) and leg pain (7.3-1.6) were significantly improved after surgery. Multivariate logistic regression analysis demonstrated that high body mass index, history of previous surgery, preoperative disability, weakness, and disc degeneration were related to incomplete clinical improvement. There were 15 recurrent LDH (7.7%) with a total of 12 revision surgeries (6.2%). CONCLUSIONS: We identified independent risk factors associated with incomplete clinical improvement following TELD, including overweight, significant preoperative disability or weakness and history of previous surgery. Advanced age, disc degeneration, vacuum phenomenon, and spondylolisthesis were also possible risk factors. Recognizing these risk factors would help decide whether patients are good candidates for TELD, and optimize the surgical planning preoperatively to achieve good surgical results.

Is navigation beneficial for transforaminal endoscopic lumbar foraminotomy? A preliminary comparison study with fluoroscopic guidance.

PURPOSE: The primary purpose of this study was to determine radiation exposure of the surgeon during transforaminal endoscopic lumbar foraminotomy (TELF). Secondary purpose of this study was to compare clinical and radiologic outcomes between TELF under C-arm fluoroscopic guidance (C-TELF) and O-arm navigation-guided TELF (O-TELF). METHODS: The author reviewed patients' medical records who underwent TELF at our institute from June 2015 to November 2022. A total of 40 patients were included (18 patients with C-TELF and 22 with O-TELF). Basic demographic data were collected. Preoperative/postoperative visual analog scale (VAS) and Oswestry Disability Index (ODI) were recorded at the outpatient clinic. Radiologic features were compared on X-rays at each follow-up. The degree of foraminal expansion was measured/compared through MRI. In the C-TELF group, the amount of exposure was calculated with a dosimeter. RESULTS: Average surgeon's effective dose in the C-TELF group was 0.036 mSv. In the case of the O-TELF group, there was no radiation exposure during operation. However, the operation time in the O-TELF group was about 37 min longer than that in the C-TELF group. There were significant improvements in VAS/ODI after operation in both groups. Complications were identified in three patients. CONCLUSION: O-TELF showed similarly favorable clinical and radiologic outcomes to C-TELF in lumbar foraminal stenosis, including complication rate. Compared to C-TELF, O-TELF has an advantage of not wearing a lead apron since the operator is not exposed to radiation. However, the operation time was longer with O-TELF due to O-arm setting time. Because there are pros and cons, the choice of surgical method depends on the surgeon's preference.

Bibliometric analysis and description of research trends on transforaminal full-endoscopic approach on the spine for the last two-decades.

OBJECTIVE: The study aims to assess the current development status of transforaminal full-endoscopic spine surgery (TFES) by exploring and analyzing the published literature to obtain an overview of this field and discover the evolution and emerging topics that are underrepresented. METHODS: Using Bibliometrix, CiteSpace, and VOSviewer, we analyzed the bibliometric data selected from the Web of Science Core Collection between January 2002 and November 2022. The descriptive and evaluative analyses of authors, institutes, countries, journals, keywords, and references are compiled. The quantity of research productivity was measured by the number of publications that were published. A quality indicator was thought to be the number of citations. In the bibliometric analysis of authors, areas, institutes, and references, we calculated and ranked the research impact by various metrics, such as the h-index and m-index. RESULTS: A total of 628 articles were identified in the field of TFES by the 18.73% annual growth rate of research on the subject from 2002 to 2022, constituting the documents are by 1961 authors affiliated with 661 institutions in 42 countries or regions and published in 117 journals. The USA (n = 0.20) has the highest international collaboration rate, South Korea has the highest H-index value (h = 33), and China is ranked as the most productive country (n = 348). Brown univ., Tongji univ., and Wooridul Spine represented the most productive institutes ranked by the number of publications. Wooridul Spine Hospital demonstrated the highest quality of paper publication. The Pain Physician had the highest h-index (n = 18), and the most cited journal with the earliest publication year in the area of FEDS is Spine (t = 1855). CONCLUSION: The bibliometric study showed a growing trend of research on transforaminal full-endoscopic spine surgery over the past 20 years. It has shown a significant increase in the number of authors, institutions, and international collaborating countries. South Korea, the United States, and China dominate the related areas. A growing body of evidence has revealed that TFES has leapfrogged from its infancy stage and gradually entered a mature development stage.

Minimally invasive endoscopy in spine surgery: where are we now?

INTRODUCTION: Endoscopic spine surgery (ESS) is a minimally invasive surgical technique that offers comparable efficacy and safety with less collateral damage compared to conventional surgery. To achieve clinical success, it is imperative to stay abreast of technological advancements, modern surgical instruments and technique, and updated evidence. PURPOSES: To provide a comprehensive review and updates of ESS including the nomenclature, technical evolution, bibliometric analysis of evidence, recent changes in the spine communities, the prevailing of biportal endoscopy, and the future of endoscopic spine surgery. METHODS: We conducted a comprehensive review of the literature on ESS for the mentioned topics from January 1989 to November 2022. Three major electronic databases were searched, including MEDLINE, Scopus, and Embase. Covidence Systematic Review was used to organize the eligible records. Two independent reviewers screened the articles for relevance. RESULTS: In total, 312 articles were finally included for review. We found various use of nomenclatures in the field of ESS publication. To address this issue, we proposed the use of distinct terms to describe the biportal and uniportal techniques, as well as their specific approaches. In the realm of technical advancement, ESS has rapidly evolved from addressing disc herniation and spinal stenosis to encompassing endoscopic fusion, along with technological innovations such as navigation, robotics, and augmented reality. According to bibliometric analysis, China, South Korea, and the USA have accounted for almost three-quarters of total publications. The studies of the biportal endoscopy are becoming increasingly popular in South Korea where the top ten most-cited articles have been published. The biportal endoscopy technique is relatively simple to adopt, as it relies on a more familiar approach, requires less expensive instruments, has a shorter learning curve, and is also well-suited for interbody fusion. The uniportal approach provided the smallest area of soft tissue dissection. While robotics and augmented reality in ESS are not widely embraced, the use of navigation in ESS is expected to become more streamlined, particularly with the emergence of recent electromagnetic-based navigation technologies. CONCLUSIONS: In this paper, we provide a comprehensive overview of the evolution of ESS, as well as an updated summary of current trends in the field, including the biportal and uniportal approaches. Additionally, we summarize the nomenclature used in ESS, present a bibliometric analysis of the field, and discuss future directions for the advancement of the field.

Full-Endoscopic Lumbar Discectomy Approach Selection: A Systematic Review and Proposed Algorithm.

STUDY DESIGN: A systematic review of the literature to develop an algorithm formulated by key opinion leaders. OBJECTIVE: This study aimed to analyze currently available data and propose a decision-making algorithm for full-endoscopic lumbar discectomy for treating lumbar disc herniation (LDH) to help surgeons choose the most appropriate approach [transforaminal endoscopic lumbar discectomy (TELD) or interlaminar endoscopic lumbar discectomy (IELD)] for patients. SUMMARY OF BACKGROUND DATA: Full-endoscopic discectomy has gained popularity in recent decades. To our knowledge, an algorithm for choosing the proper surgical approach has never been proposed. MATERIALS AND METHODS: A systematic review of the literature using PubMed and MeSH terms was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Patient samples included patients with LDH treated with full-endoscopic discectomy. The inclusion criteria were interventional research (randomized and nonrandomized trials) and observation research (cohort, case-control, case series). Exclusion criteria were case series and technical reports. The criteria used for selecting patients were grouped and analyzed. Then, an algorithm was generated based on these findings with support and reconfirmation from key expert opinions. Data on overall complications were collected. Outcome measures included zone of herniation, level of herniation, and approach (TELD or IELD). RESULTS: In total, 474 articles met the initial screening criteria. The detailed analysis identified the 80 best-matching articles; after applying the inclusion and exclusion criteria, 53 articles remained for this review. CONCLUSIONS: The proposed algorithm suggests a TELD for LDH located in the foraminal or extraforaminal zones at upper and lower levels and for central and subarticular discs at the upper levels considering the anatomic foraminal features and the craniocaudal pathology location. An IELD is preferred for LDH in the central or subarticular zones at L4/L5 and L5/S1, especially if a high iliac crest or high-grade migration is found.

Automatic Detection, Classification, and Grading of Lumbar Intervertebral Disc Degeneration Using an Artificial Neural Network Model.

BACKGROUND AND OBJECTIVES: Intervertebral disc degeneration (IDD) is a common cause of symptomatic axial low back pain. Magnetic resonance imaging (MRI) is currently the standard for the investigation and diagnosis of IDD. Deep learning artificial intelligence models represent a potential tool for rapidly and automatically detecting and visualizing IDD. This study investigated the use of deep convolutional neural networks (CNNs) for the detection, classification, and grading of IDD. METHODS: Sagittal images of 1000 IDD T2-weighted MRI images from 515 adult patients with symptomatic low back pain were separated into 800 MRI images using annotation techniques to create a training dataset (80%) and 200 MRI images to create a test dataset (20%). The training dataset was cleaned, labeled, and annotated by a radiologist. All lumbar discs were classified for disc degeneration based on the Pfirrmann grading system. The deep learning CNN model was used for training in detecting and grading IDD. The results of the training with the CNN model were verified by testing the grading of the dataset using an automatic model. RESULTS: The training dataset of the sagittal intervertebral disc lumbar MRI images found 220 IDDs of grade I, 530 of grade II, 170 of grade III, 160 of grade IV, and 20 of grade V. The deep CNN model was able to detect and classify lumbar IDD with an accuracy of more than 95%. CONCLUSION: The deep CNN model can reliably automatically grade routine T2-weighted MRIs using the Pfirrmann grading system, providing a quick and efficient method for lumbar IDD classification.

Subsidence of Interbody Cage Following Oblique Lateral Interbody Fusion: An Analysis and Potential Risk Factors.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: This study aimed to report the incidence and potential risk factors of polyetheretherketone (PEEK) cage subsidence following oblique lateral interbody fusion (OLIF) for lumbar degenerative diseases. We proposed also an algorithm to minimize subsidence following OLIF surgery. METHODS: The study included a retrospective cohort of 107 consecutive patients (48 men and 59 women; mean age, 67.4 years) who had received either single- or multi-level OLIF between 2012 and 2019. Patients were classified into subsidence and non-subsidence groups. PEEK cage subsidence was defined as any violation of either endplate from the computed tomography scan in both sagittal and coronal views. Preoperative variables such as age, sex, body mass index, bone mineral density (BMD) measured by preoperative dual-energy X-ray absorptiometry, smoking status, corticosteroid use, diagnosis, operative level, multifidus muscle cross-sectional area, and multifidus muscle fatty degeneration were collected. Age-related variables (height and length) were also documented. Univariate and multivariate logistic regression analyses were used to analyze the risk factors of subsidence. RESULTS: Of the 107 patients (137 levels), 50 (46.7%) met the subsidence criteria. Higher PEEK cage height had the strongest association with subsidence (OR = 9.59, P < .001). Other factors significantly associated with cage subsistence included age >60 years (OR = 3.15, P = .018), BMD <-2.5 (OR = 2.78, P = .006), and severe multifidus muscle fatty degeneration (OR = 1.97, P = .023). CONCLUSIONS: Risk factors for subsidence in OLIF were age >60 years, BMD < -2.5, higher cage height, and severe multifidus muscle fatty degeneration. Patients who had subsidence had worse early (3 months) postoperative back and leg pain.

Transforaminal Versus Interlaminar Endoscopic Lumbar Discectomy for Lumbar Disc Herniation: A Systematic Review and Meta-Analysis.

STUDY DESIGN: Meta-analysis and systematic review. OBJECTIVE: This study aims to investigate and compare patient-reported outcomes, perioperative data, and complications between 2 common endoscopic approaches for lumbar disc herniation: transforaminal and interlaminar endoscopic lumbar discectomy, by published high-quality evidence. METHODS: Electronic databases were searched for reported outcomes following TELD and IELD. Oswestry Disability Index (ODI), visual analog scale of back (VASB) and leg pain (VASL), and MacNab criteria were evaluated. Operative time, hospital stays, blood loss, radiation exposure, and complications were investigated. Odds ratio (OR) and mean differences (MD) with 95% confidence intervals (CI) were calculated using random and fixed-effect models. RESULTS: Total of 1948 patients from 18 studies were included, consisting of 1006 patients (51.6%) in TELD group and 942 (48.4%) patients in IELD group. TELD had better improvement of postoperative ODI (MD = 1.26; 95% CI: .07-2.16; P = .04), postoperative VASB (MD = -.23; 95% CI: -.40 to -.05; P = .01) and last follow-up VASB (MD = -.25; 95% CI: -.41 to -.09; P = .002), but with longer operative time (MD = 10.1 min; 95% CI: 1.925-18.77; P < .00001) and more fluoroscopic time (SMD = 4.12; 95% CI: 3.22-5.03; P < .00001), especially in L5-S1 operation. Bed rest time was significantly longer following IELD, with no difference in VASL, hospital stays, or complication. CONCLUSION: We found comparable clinical outcomes in terms of ODI, VAS, patient satisfaction, hospital stays, and complication between both techniques. TELD required more radiation exposure and longer operative time at L5-S1 level than IELD. Our study provided results to help consider appropriate approaches for selected patients and informed consent of benefits from each approach.

The Endoscopic Lumbar Interbody Fusion: A Narrative Review, and Future Perspective.

Lumbar interbody fusion stands as a preferred surgical solution for degenerative lumbar spine diseases. The procedure primarily aims to establish lumbar segment stability, directly addressing patient symptoms associated with spinal complications. Traditional open surgery, though effective, is linked with notable morbidities and extended recovery time. To mitigate these concerns, minimally invasive surgery (MIS) has garnered significant popularity, presenting an appealing alternative with numerous benefits such as reduced soft tissue trauma, decreased blood loss, and expedited recovery. Among MIS procedures, full endoscopic spinal surgery, characterized by its minimal invasiveness, holds the potential to further minimize morbidities while enhancing surgical outcomes. Endoscopic lumbar interbody fusion, a novel procedure within this paradigm, has gained attention for offering advantages comparable to those of minimally invasive transforaminal lumbar interbody fusion. However, the safety, efficacy, and associated surgical techniques and instrument design of this method continue to be subjects of ongoing debate. This paper critically reviews current evidence on the safety, efficacy, and advantages of endoscopic lumbar spinal interbody fusion, examining whether it could indeed supersede existing mainstream techniques.

An Expanded Surgical Corridor of Oblique Lateral Interbody Fusion at L4-5: A Magnetic Resonance Imaging Study.

OBJECTIVE: We introduced a new preoperative method, the "expanded surgical corridor," to evaluate the actual safety corridor, which may expand the possibility of performing oblique lateral interbody fusion (OLIF). METHODS: Axial T2-weighted magnetic resonance images at the L4-5 disc level of 511 lumbar degenerative disease patients was evaluated. The distance between the medial edge of the left-sided psoas muscle and the major artery was measured as the conventional surgical corridor (CSc). The distance between the major vein and lumbar plexus was measured as the expanded surgical corridor (ESc). RESULTS: The mean CSc and ESc were 13.9 ± 8.20 and 37.43 ± 10.1 mm, respectively. No surgical corridor was found in 7.05% of CSc and 1.76% of ESc, small corridor ( ≤ 1 cm) was found in 27.40% of CSc and 0.59% of ESc, moderate corridor (1-2 cm) was found in 42.07% of CSc and 1.96% of ESc, and large corridor ( > 2 cm) was found in 23.48% of CSc and 95.69% of ESc. A total of 33.83% (45 of 133) of whom were preoperatively categorized as having a limited surgical corridor by conventional measurement, underwent OLIF L4-5 successfully. CONCLUSION: By using the ESc, only 2.35% were categorized as having a limited surgical corridor. The other 97.65% of the patients had an approachable corridor that could be successfully operated by experienced spine surgeons who employ meticulous surgical dissection and thorough understanding of the anatomical structures. The ESc may represent true accessibility to the disc space for OLIF, particularly at the L4-5 level.