CASE:An 82-year-old woman presented with right medial thigh pain. Her medical history included multiple lumbar decompression and fusion surgeries. She was diagnosed with L3 radiculopathy secondary adjacent segment disease (ASD) after lumbar fusion. Full-endoscopic spine surgery (FESS) was performed for targeted decompression. Preoperative planning was conducted using AI-assisted 3-dimensional (3D) magnetic resonance imaging (MRI)/computed tomography (CT) fusion images. The procedure was completed under local anesthesia, resulting in postoperative pain relief. At the 3-year follow-up, the patient remained asymptomatic with no symptom recurrence. CONCLUSION:FESS, combined with detailed surgical planning using artificial intelligence -assisted 3D MRI/CT fusion imaging, may be an effective treatment strategy for ASD.

Background Magnetic resonance imaging (MRI) is the gold standard for diagnosing lumbar canal stenosis (LCS), but it may be contraindicated in patients with implants or claustrophobia. Computed tomographic myelography (CTM) is an alternative imaging modality but requires an invasive procedure. This study aimed to generate synthetic CTM images from plain CT using a modified Cycle GAN and evaluate their diagnostic reliability. Methods The training dataset included 111 patients from 3 hospitals, comprising 21,034 plain CT and 21,062 CTM images. The external test dataset included 60 patients from another hospital who underwent plain lumbar CT and MRI, including 20 patients each with LCS, lumbar disc herniation, and no spinal disease. A modified Cycle GAN incorporating a Convolutional Block Attention Module and spectral normalization was trained to translate plain CT into synthetic CTM. Quantitative performance was assessed using Intersection over Union, F1 score, Structural Similarity Index Measure, and Peak Signal-to-Noise Ratio. Two spine surgeons independently graded stenosis on synthetic CTM and MRI using the Lee staging system. Intrarater reliability, inter-rater reliability, and agreement between synthetic CTM and MRI were evaluated using weighted kappa coefficients. Results For spinal canal enhancement, the modified Cycle GAN achieved a mean Intersection over Union of 0.70 and F1 score of 0.80. Bone structures showed a mean Intersection over Union of 0.89 and F1 score of 0.94. Surrounding tissues demonstrated a Structural Similarity Index Measure of 0.91 and Peak Signal-to-Noise Ratio of 30 dB. Synthetic CTM showed almost perfect intrarater reliability and substantial inter-rater reliability. Agreement between synthetic CTM and MRI was substantial. Conclusions Synthetic CTM generated from plain CT demonstrated acceptable quantitative accuracy and clinical reliability for grading LCS. Although spatial overlap was imperfect and nerve-root depiction was not validated, this method may offer a noninvasive diagnostic alternative for patients ineligible for MRI.

PURPOSE:Patients with ossification of the posterior longitudinal ligament (OPLL) may require lumbar surgery due to ossified lesions and degenerative changes. However, risk stratification for lumbar intervention remains underexplored. We aimed to identify predictors of lumbar surgery in patients with OPLL. METHODS:We retrospectively analyzed 178 OPLL patients who underwent whole-spine computed tomography (CT) (2007-2023). Patients were classified according to whether they underwent lumbar surgery. CT obtained prior to lumbar surgery or during conservative follow-up was reviewed. Imaging parameters, including ossification distribution and degenerative changes, were compared between groups and analyzed using multivariable logistic regression to identify independent predictors. RESULTS:Lumbar surgery was performed in 70 (39.3%) patients. The surgery group exhibited higher body mass index and greater prevalence of thoracolumbar ankylosis, thoracic and lumbar OPLL, lumbar ossification of the ligamentum flavum (OLF), and intervertebral disc (IVD) gas. Multivariable analysis identified lumbar OLF (OR, 6.49; 95% CI, 2.60-16.25) and lumbar IVD gas (OR, 5.75; 95% CI, 2.37-13.97) as independent risk factors. Coexisting OPLL and OLF at the same level was associated with younger surgical age and greater neurological severity. CONCLUSIONS:Using whole-spine CT, we demonstrated that patients requiring lumbar surgery frequently exhibited a diffuse whole-spine ossification phenotype, characterized by thoracolumbar OPLL and ankylosis. Lumbar OLF and IVD gas were identified as independent risk factors; notably, lumbar OLF reflects this generalized ossification tendency, whereas disc gas indicates mechanical stress and degeneration. These findings support whole-spine CT-based risk stratification and longitudinal monitoring in patients with OPLL.

BACKGROUND CONTEXT:Lumbar ossification of the posterior longitudinal ligament (L-OPLL) has been underrecognized and remains poorly characterized clinically. We hypothesized that L-OPLL constitutes a distinct phenotype within the broader OPLL spectrum, sharing features of obesity and diffuse spinal ligament ossification. PURPOSE:To evaluate the clinical and radiographic features of L-OPLL and assess their relationship with diffuse spinal ligament ossification and obesity-related factors. STUDY DESIGN:Cross-sectional study with a replication cohort. PATIENT SAMPLE:A total of 186 patients with OPLL were diagnosed using whole-spine computed tomography (CT) at a regional spine center in Japan (2007-2024). Additionally, 75 asymptomatic individuals with OPLL from a population-based health screening cohort comprised the replication cohort. OUTCOME MEASURES:Patient background, including BMI, was assessed. Spinal ligament ossification was evaluated using whole-spine computed tomography. The severity of ossification was scored for 4 ligaments-OPLL, ossification of the anterior longitudinal ligament (OALL), ossification of the ligamentum flavum (OLF), and ossification of the supra/interspinous ligament (OSIL)-and summed to define the ossification index (OS index). Regional scores from the cervical, thoracic, and lumbar spine were combined to calculate the total index. METHODS:In the primary analysis, patients were classified into L-OPLL and non-L-OPLL groups, and their clinical and radiographic features were compared. Multiple linear regression analysis was used to assess the independent association between L-OPLL and OS index. In the secondary analysis, patients were classified into three groups: localized cervical OPLL (C-OPLL), thoracic OPLL (T-OPLL), and L-OPLL groups, and comparisons were made between the localized C-OPLL group and the T- and L-OPLL groups. RESULTS:The L-OPLL group had a significantly higher BMI (median 27.5 vs 26.0 kg/m², p=.003) and greater prevalence of obesity than the non-L-OPLL group, along with significantly elevated thoracic OPLL and OLF indices. Multiple linear regression analysis confirmed that L-OPLL was independently associated with a higher OS index (regression coefficient: 0.448, 95% confidence interval: 0.162 to 0.735, p=.002). The L-OPLL group also exhibited significantly higher BMI and OS index than the localized C-OPLL group, primarily driven by increased thoracic and lumbar OPLL and OLF. The replication cohort results were consistent with an association between L-OPLL, obesity, and diffuse ligament ossification. CONCLUSIONS:L-OPLL is rarely an isolated lumbar lesion; instead, it commonly coexists with extensive spinal ligament ossification and marked obesity. Its distinct clinical and radiographic features support classification as a separate entity within the broader OPLL spectrum.

Purpose The transforaminal (TF) approach through Kambin’s triangle is the cornerstone of minimally invasive spinal surgery. Although degenerative lumbar spondylolisthesis (DS) is a common indication, its quantitative effect on the three-dimensional (3D) anatomy of the safety zone remains unclear. We aimed to evaluate the 3D morphological alterations of the TF safety zone in DS using magnetic resonance imaging (MRI)/computed tomography (CT) fusion imaging. Methods We retrospectively analysed 60 patients (120 sides) categorised into three groups (n = 20 each): no-slip, Meyerding gade 1, and gade 2 spondylolisthesis. Using a validated 3D MRI/CT fusion model, we simulated a 45° transforaminal surgical trajectory at the L4/5 level. The width (horizontal distance from the superior articular process [SAP] to the exiting nerve root), height (inter-endplate distance), and total safety zone area were quantified. Results A divergent response was observed as vertebral slippage progressed. Width significantly increased with slip degree (no-slip: 6.2 mm; grade 2:7.5 mm; r = 0.26, p < 0.05), reflecting relative SAP posterior displacement. Conversely, height demonstrated a negative correlation (no-slip: 4.8 mm; grade 2:3.5 mm; r=-0.67, p < 0.01) due to disc height loss. The total area demonstrated a significant negative correlation with slip percentage (r = -0.40, p < 0.01). Conclusions The TF safety zone 3D morphology was significantly altered by DS progression and characterised by a severe height decrease and a paradoxical width increase. This structural remodelling flattened the safety zone profile. Our quantitative analysis provided a new anatomical baseline for understanding the unique spatial constraints of the TF approach in vertebral slippage.

Study DesignProspective international multicenter observational cohort study.ObjectiveTo evaluate the relationships among distal radius and ulna (DRU) classification, growth velocity, and scoliosis progression patterns in adolescent idiopathic scoliosis (AIS) using longitudinal interval-based analyses in a multinational Asian cohort.MethodsPatients aged 10-18 years with AIS were prospectively enrolled from multiple Asian centers. DRU classification, Sanders classification, Risser stage, standing height, and Cobb angle were assessed at approximately 4-6-month intervals. Only observations obtained before brace treatment or surgery were included. Height velocity and Cobb progression velocity were calculated between consecutive visits. Stage-specific patterns were evaluated using boxplots, nonparametric analyses, and mixed-effects models adjusted for age, sex, and baseline Cobb angle.ResultsAmong 329 enrolled patients, 236 patients contributing 618 longitudinal intervals met eligibility criteria. Mean age was 13.5 years, and mean baseline Cobb angle was 24.0°. Height velocity peaked at Radius stage 6 (0.62 cm/month) and Ulnar stage 5 (0.68 cm/month). Cobb progression velocity was greatest at Radius stage 6 (0.31°/month); among adequately represented Ulnar stages, progression velocity was greatest at stage 5 (0.27°/month). Spearman analyses showed only very weak correlations between skeletal maturity stage and Cobb progression velocity. Mixed-effects analyses suggested nonlinear progression patterns, with increased progression velocity at earlier to intermediate maturity stages.ConclusionsDRU classification demonstrated stage-dependent progression patterns, with peak scoliosis progression generally occurring approximately one DRU stage after peak height velocity. These findings suggest that DRU classification may help identify skeletal maturity phases associated with accelerated scoliosis progression in AIS.

Full-endoscopic discectomy via the transforaminal approach (FED-TF) carries the risk of exiting nerve root (ENR) injury, and its feasibility at the lumbosacral level may be limited by anatomical constraints. Precise preoperative assessment is therefore essential. This study aimed to evaluate the accuracy, safety, and clinical efficacy of artificial intelligence (AI)-assisted three-dimensional (3D) MRI/CT fusion imaging for preoperative simulation of FED-TF in a retrospective case series. This retrospective case series included 40 patients with L5/S1 intervertebral disc herniation who were judged feasible for FED-TF without superior articular process (SAP) resection based on preoperative simulations. A virtual endoscopic axis was established to avoid interference from the iliac crest, SAP, and ENR. The axial and sagittal angles of the virtual axis were measured and compared with the actual endoscopic insertion angles postoperatively. Clinical outcomes were assessed using the visual analogue scale (VAS) for leg and low back pain, and the Japanese Orthopaedic Association (JOA) scores perioperatively. All the procedures were completed without any complications. The mean axial angle was 59.9° (simulation) versus 58.4° (actual), with no significant difference (p = 0.236). The sagittal angle was 8.6° (simulation) versus 8.9° (actual), with no significant difference (p = 0.739). The VAS score for leg pain improved significantly from 7.0 preoperatively to 2.1 on day 1 and 1.5 at day 90. The VAS scores for low back pain significantly improved from 5.5 to 3.5 and 2.1, respectively. The JOA scores improved significantly from 13.9 preoperatively to 21.5 on day 1 and 25.7 on day 90 (all p < 0.05). AI-assisted 3D MRI/CT fusion imaging demonstrated high accuracy in preoperative simulation and enabled safe and effective FED-TF in this case series. However, because CT and MRI were acquired separately and only cases not requiring SAP resection were included, further studies with larger cohorts and control groups are needed to validate and expand the applicability of this technique.

Full-endoscopic lumbar discectomy with the transforaminal approach (FED-TF) is a minimally invasive spinal surgery for lumbar disc herniation. However, anatomical constraints at the lumbosacral levels (L5/S1), such as the iliac crest, present anatomical challenges. This study aimed to evaluate the simulation-based anatomical feasibility of the FED-TF approach at L5/S1 using three-dimensional (3D) fusion imaging of lumbosacral nerve roots from magnetic resonance imaging (MRI) and of the lumbosacral spine and iliac from computed tomography (CT) images. Moreover, the study assessed simulation-based anatomical feasibility trends based on age, sex, and anatomical obstacles. A total of 208 cases (416 simulations) were randomly selected from patients who underwent 3D MRI/CT fusion imaging. Using these images, we assessed the simulation-based anatomical feasibility of reaching the medial edge of the L5 pedicle at the L5/S1 intervertebral disc level without resection of the superior articular process (SAP). In cases judged anatomically infeasible on simulation, anatomical obstacles were analysed by age group and sex. The FED-TF approach at L5/S1 was judged anatomically feasible without SAP resection in 62.5

STUDY DESIGN:A retrospective cross-sectional clinical study. OBJECTIVE:The purpose of the present study was to investigate the incidence of White cord syndrome (WCS) after laminoplasty (LAP) of the Kirita-Miyazaki method in 20 years. SUMMARY OF BACKGROUND DATA:Sequential 244 cases of cervical LAP in 20 years in a single institute. METHODS:We identified cases performed LAP for cervical myelopathy, followed by an independent record review for more precise inclusion. The primary target was the WCS, but we also collected other minor complications and obtained their incidence. RESULTS:We discovered one WCS case of 244 cases of cervical LAP (0.4%). The case was a 62-year-old man with diffuse ossification of the posterior longitudinal ligament causing very severe spinal cord compression. Other complications were dura mater tear in five cases (2%); C5 palsy in 19 cases (7.8%); C6 palsy in four cases (1.6%); sensation disorder in four cases (1.6%); surgical site infection in two cases (0.8%); epidural hematoma in one case (0.4%); incomplete decompression at the edge of LAP in one case (0.4%); occurrence of flexion myelopathy in one case (0.4%). CONCLUSIONS:The incidence of WCS secondary to cervical spine LAP was as low as one per 4880 person-years, lower than those of previous studies, while the rates of other typical complications were comparable. LEVEL OF EVIDENCE:Level 3.

BACKGROUND CONTEXT: Recent studies have demonstrated a close association between the development of ossification of the posterior longitudinal ligament (OPLL) and obesity. However, the association between OPLL and visceral fat obesity, which is prevalent in the Asian population, remains unexplored. PURPOSE: To examine the impact of visceral fat obesity on the development of asymptomatic OPLL. STUDY DESIGN: Single-institution cross-sectional study. PATIENT SAMPLE: Between 2020 and 2021, data were collected from 249 Japanese individuals (147 men and 102 women) who underwent computed tomography (CT) to assess both the visceral fat content and OPLL. OUTCOME MEASURES: We assessed patient background information, serum data, and CT images, including the abdominal circumference (cm), total fat area (cm(2)), visceral fat area (cm(2)), and subcutaneous fat area (cm(2)) at the umbilicus level. OPLL localization was assessed using whole-spine CT images. METHODS: The individuals were categorized into 4 groups based on obesity and visceral fat: nonobesity without visceral fat (n=85), obesity without visceral fat (n=18), nonobesity with visceral fat (n=44), and obesity with visceral fat (n=102). OPLL was classified as localized or diffuse when present in the cervical spine alone or in the cervical and thoracic spine, respectively. The prevalence of each type of OPLL was compared between the groups. Multivariable analysis was conducted to calculate the effect size of body mass index (BMI) on the prevalence of OPLL, comparing the high and low visceral fat groups. RESULTS: The obesity with visceral fat group exhibited a significantly higher proportion of diffuse OPLL than did the nonobesity without visceral fat group (27.5% vs 7.1%, p<.001). The effect size of BMI for the occurrence of diffuse OPLL was 2.1 times greater in the high visceral fat group (odds ratio [OR], 3.12; 95% confidence interval [CI], 1.66-5.87) than in the low visceral fat group (OR, 1.44; 95% CI, 0.64-3.22). CONCLUSIONS: Our data show that visceral fat, in conjunction with BMI, influences the occurrence of OPLL in the Japanese population. This supports the hypothesis that systemic metabolic disorders share a disease mechanism with OPLL and indicates that the high prevalence of OPLL in Japan may be attributed to physical characteristics that promote visceral fat accumulation. (c) 2025 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

PURPOSE:This study aimed to develop deep learning algorithms (DLAs) utilising convolutional neural networks (CNNs) to classify cervical spondylotic myelopathy (CSM) and cervical spondylotic radiculopathy (CSR) from plain cervical spine radiographs. METHODS:Data from 300 patients (150 with CSM and 150 with CSR) were used for internal validation (IV) using five-fold cross-validation strategy. Additionally, 100 patients (50 with CSM and 50 with CSR) were included in the external validation (EV). Two DLAs were trained using CNNs on plain radiographs from C3-C6 for the binary classification of CSM and CSR, and for the prediction of the spinal canal area rate using magnetic resonance imaging. Model performance was evaluated on external data using metrics such as area under the curve (AUC), accuracy, and likelihood ratios. RESULTS:For the binary classification, the AUC ranged from 0.84 to 0.96, with accuracy between 78% and 95% during IV. In the EV, the AUC and accuracy were 0.96 and 90%, respectively. For the spinal canal area rate, correlation coefficients during five-fold cross-validation ranged from 0.57 to 0.64, with a mean correlation of 0.61 observed in the EV. CONCLUSION:DLAs developed with CNNs demonstrated promising accuracy for classifying CSM and CSR from plain radiographs. These algorithms have the potential to assist non-specialists in identifying patients who require further evaluation or referral to spine specialists, thereby reducing delays in the diagnosis and treatment of CSM.

Introduction: To compare the clinical outcomes between a full-endoscopic transforaminal approach lumbar interbody fusion (TF-LIF) using the percutaneous endoscopic transforaminal lumbar interbody fusion (PETLIF) system and a minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Methods: A total of 102 patients (80 females, 22 males; mean age: 70.0 years) with degenerative lumbar spine disorders who underwent PETLIF and were followed up for 2 years were assigned to the PETLIF group. Based on age, sex, and operated lumbar levels in the PETLIF group, 100 patients (71 women and 29 men; mean age: 68.9 years) who underwent MIS-TLIF were randomly selected and included in the MIS-TLIF group. This retrospective investigation included surgical data, radiographic assessment, and clinical outcomes. Results: The fusion rate was 95.1% and 96.0% in the PETLIF and MIS-TLIF groups, respectively (P=0.38). The decrease in hemoglobin levels from before surgery to 1 day after surgery was significantly lower in the PETLIF group than in the MIS-TLIF group (P<0.01). Five patients had detectable transient neurologic disorders after PETLIF that were resolved within 3 months. The increase in the local lordosis angle from before surgery to the final follow-up was significantly higher in the MIS-TLIF group than in the PETLIF group (P<0.01). Clinical scores were comparable between the two groups. Conclusions: Compared with MIS-TLIF, PETLIF showed excellent bone fusion rate and clinical outcomes. It was minimally invasive, resulting in less blood loss. However, exiting nerve root injury was a PETLIF-specific complication, and proper preventive management, including techniques to enlarge the Kambin's triangle, is required.

Background:Ossification of the posterior longitudinal ligament (OPLL) is relatively common in East Asian populations, with a recently revealed link to obesity. However, evidence linking OPLL with visceral fat obesity, which is prevalent in the Asian population, is insufficient. We aimed to examine the association between visceral fat obesity and the development of OPLL. Methods:In a single-center case-control study, data were collected from 120 Japanese patients diagnosed with OPLL and 91 controls without spinal ligament ossification identified during health screenings. From 2020 to 2023, all participants underwent computed tomography to assess visceral fat content and spinal ligament ossification. OPLL was classified as localized (cervical spine) or diffuse (thoracic/lumbar spine). Multivariable logistic regression was conducted to assess the effect size (odds ratio [OR]) of body mass index on the incidence of OPLL and to compare outcomes between groups with a high and low visceral/subcutaneous fat area (V/S) ratio. Results:The proportion of patients with visceral fat obesity was significantly higher in both the localized and diffuse OPLL groups than in the controls (58.9% vs. 64.1% vs. 25.2%, p < 0.05). Patients with OPLL had a higher rate of comorbid visceral fat obesity than the propensity score-matched controls did (56.8% vs. 18.1%, p < 0.001). The effect of BMI on the development of diffuse OPLL was 2.6-fold greater in the high V/S ratio group (OR, 9.50; 95% confidence interval [CI], 2.11 to 42.71) than in the low V/S ratio group (OR, 3.56; 95% CI, 1.51-8.37). Conclusions:Visceral fat obesity was associated with the development of OPLL, particularly diffuse OPLL. The modifying effect of visceral fat accumulation with overweight status was more strongly associated with diffuse OPLL than was that of subcutaneous fat combined with an overweight status. Level of Evidence:Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

A four-dimensional (4D) anatomical spinal reconstruction (ASR) technique and anatomical notch-free, pre-bent rods have been developed for thoracic adolescent idiopathic scoliosis (AIS) surgery. We aimed to evaluate the outcomes of ASR using notch-free rods through multiple comparisons with conventional methods, including the simultaneous double-rod rotation technique (SDRRT) and ASR using manually bent notched rods. Three consecutive series of 126 patients who underwent surgery for Lenke 1 AIS curves were prospectively followed up for 2 years after surgery. The operative time was significantly shorter in the ASR using notch-free rods group than in the other two groups (P < 0.05). The correction rate of the main thoracic (MT) curve was higher in the ASR group than in the SDRRT group (P < 0.01). Thoracic kyphosis (TK) was greater in the ASR using notch-free rods group than in the other two groups at the final follow-up (P < 0.01). The percentage of patients with a T6–T8 location of the TK apex was greater in the ASR using notch-free rods group than in the SDRRT group at the final follow-up (P < 0.01). ASR using notch-free rods created an anatomical TK, contributing to a shorter operative time and standardization of the procedure.

Introduction: Delayed diagnosis and therapy initiation for pyogenic spondylitis can have severe and fatal consequences. Early diagnosis and intervention are crucial in the treatment of pyogenic spondylitis. This multicenter cross-sectional study with prospective case series aimed to identify factors influencing the time from symptom onset to the diagnosis of pyogenic spondylitis. Methods: Patients hospitalized with pyogenic spondylitis between 2019 and 2023 were included. Patients were classified into 2 groups: the delayed diagnosis group (>30 days from the onset of initial symptoms to the diagnosis of pyogenic spondylitis) and the early diagnosis group (within 29 days). Risk factors for delayed diagnosis were analyzed. Results: A total of 74 patients (42 men and 32 women; mean age: 70.2 years) from 5 institutions were included. Univariate analysis of risk factors for delayed diagnosis revealed that the significant risk factors included advanced age (p=0.03), low white blood cell count (p<0.01), low C-reactive protein level (p<0.05), and semi-rigid spinal level, based on the spinal instability neoplastic score classification (p=0.05). Multivariate analysis for delayed diagnosis showed that the location at the semi-rigid spinal level was a significant risk factor (p=0.02). The vertebral bone destruction rate and abscess cavity index in the delayed diagnosis group were significantly higher than those in the early diagnosis group (p<0.01 and p<0.01, respectively). Conclusions: Significant risk factors for delayed diagnosis of pyogenic spondylodiscitis include infection at the semi-rigid thoracic spinal level. Early diagnosis of spondylodiscitis is crucial because delayed diagnosis can lead to progressive bone destruction and the formation of large abscesses. Increased awareness of thoracic spinal infections, which can easily delay diagnosis, could help in the early diagnosis and treatment of pyogenic spondylodiscitis.

PURPOSE:Lumbosacral nerve root anomalies are relatively rare but can be a risk factor for intraoperative nerve injury. However, it is often difficult to evaluate them with preoperative imaging. We developed a software that automatically generates three-dimensional (3D) nerve root images from magnetic resonance (MR) imaging using artificial intelligence (AI). This study aims to evaluate the accuracy and utility of this modality in clinical practice by conducting an epidemiological study of nerve root anomalies. METHODS:The incidence and morphology of nerve root anomalies were evaluated in the 3D images of 1,500 patients. The accuracy of the images was evaluated by comparing the images generated automatically using this AI software with those created manually by conventional methods. RESULTS:Of 1,500 cases, 53 (3.5%) had nerve root anomalies with total of 58 nerve root anomalies. With respect to the spinal level, 35 nerve root anomalies were found in the L5-S1 level, the most common (60.3%). As for morphology, 47 nerve roots (81.0%) were of the Neidre-MacNab classification Type 1. The images matched in 1,493 out of 1,500 cases (99.5%) between the two methods, and the remaining 7 cases all had nerve root abnormalities, which were detected as abnormal by the AI software. CONCLUSION:The MR nerve root 3D imaging provided a 3D visualization and understanding of nerve root morphology, including nerve root anomalies. The AI software enables easy and precise 3D nerve root imaging, which greatly aids in the preoperative evaluation for spinal surgery.

Discectomy is the current surgical procedure for lumbar intervertebral disc (IVD) herniation. Discectomy was performed to remove the IVD material and relieve the pain inflicted by nerve root compression and axonotoxic effects, such as inflammatory cytokines in the IVD material; however, defects within the IVD caused by discectomy may impair tissue healing and predispose patients to subsequent IVD degeneration. Given that viable cells with the capacity for IVD regeneration are scarce, discectomy alone is not conducive to tissue repair. Here, we report the use of an acellular, bioresorbable, ultra-purified alginate (UPAL) gel implantation system to prevent IVD degeneration after discectomy and demonstrate its feasibility and safety in phase 1/2, open-label, non-randomized clinical trials conducted at a double center. This study comprised two parts: a prospective study on UPAL gel implantation after discectomy in patients with lumbar disc herniation, and a subsequent prospective study on patients who underwent discectomy without UPAL implantation as a control group. The control group was recruited separately. The primary outcomes of this study were the feasibility and safety of UPAL implantation, and the secondary outcomes included physical function scores, self-report questionnaires (SRQs) evaluating pain and health-related quality of life and magnetic resonance imaging (MRI)-based measures of IVD tissues. The UPAL gel implantation demonstrated 100% feasibility and safety (n = 40). The physical function scores improved significantly postoperatively in both groups, with the UPAL group demonstrating greater improvements over time compared to the control group. The SRQ scores were significantly higher in the UPAL group than in the control group from the early postoperative period to 12 weeks. MRI revealed that the disc degeneration score was significantly lower in IVDs with UPAL implantation than in those that underwent discectomy alone. The findings of this study suggest that the UPAL gel is a novel therapeutic strategy after discectomy in cases of lumbar IVD herniation. Trial number: UMIN000034227, UMIN000042282.

BACKGROUND:In full-endoscopic spine surgery via transforaminal approach (FESS-TF), the outside-in method facilitates treatment for various cases; however, the technique is difficult to perform. To facilitate this procedure, we developed a duckbill release technique. In this article, we aimed to introduce the details of this technique and investigate its effectiveness. METHODS:Fifty patients who underwent FESS-TF for intervertebral disc herniation were divided into 2 groups: the conventional technique and the duckbill release technique groups. The time from the initiation of surgery to exposure of the bone outside the superior articular process was measured in both groups. The visual analog scale score for leg pain and the Japanese Orthopaedic Association score before and after surgery were compared in terms of clinical outcomes. RESULTS:No significant differences were observed between the 2 groups in terms of patient background. The approach time was 252 ± 86 seconds in the conventional group, while it was 105 ± 26 seconds in the duckbill release group, which was significantly shorter (P < 0.001). In terms of clinical outcomes, the 2 groups did not significantly differ in all endpoints of the visual analog scale score for leg pain or the Japanese Orthopaedic Association score. CONCLUSIONS:The duckbill release technique for the outside-in method in FESS-TF could be efficient because it is a simple and time-saving approach.

Objectives: To investigate whether preservation of the posterior elements protects the spine from degeneration and improves postoperative symptoms in lumbar spine laminoplasty. Methods: Eighty-five consecutive patients who underwent lumbar spine laminoplasty were retrospectively reviewed. They were non-randomly stratified into two groups, the posterior elements resection (R) group and the preservation (P) group, and they were followed for two years after surgery. We radiographically analyzed the conditions of the spine and intervertebral disc (IVD) two years after surgery. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) was used for symptom assessments. Logistic regression analysis was performed to determine whether the kissing spine was a significant factor for the outcomes in group R. Results: The 2-year D score increment and 2-year IVD height decrement was lower in group P. No difference was found in the flexion–extension angles or incidence of instability between groups. The JOABPEQ revealed higher scores in walking ability, social life function, and mental health in group P one year after surgery. Walking ability was the only score that remained higher two years after surgery. The visual analog scale of pain in the buttocks and lower limbs was lower in group P only one year after surgery. Finally, the kissing spine was not a significant factor in any outcome. Conclusions: The preserved posterior elements were considered to protect the IVD in lumbar spine laminoplasty. In addition, they positively affected postoperative health status from multiple aspects.