Background/Objectives: The external auditory meatus (EAM) is widely used as a surrogate cranial reference point, based on its proximity to the midpoint of the nasion-inion line (MNI). However, its radiographic clarity has not been thoroughly validated. This study aimed to evaluate the radiographic clarity and interobserver reproducibility of the EAM compared with the sella turcica as a control landmark. Methods: A retrospective review was performed on patients who underwent surgical correction for sagittal spinal deformity between 2021 and 2024. Preoperative standing whole-spine radiographs were analyzed. Horizontal and vertical distances from the EAM and the posterior border of the sella turcica to the MNI were measured. Radiographic clarity was categorized into three groups. Five independent neurosurgeons conducted all measurements, and interobserver reliability was assessed using the intraclass correlation coefficient with a two-way random-effects model [ICC(2,1)]. Results: The EAM was horizontally closer to the MNI (1.1 mm vs. 13.8 mm) but exhibited poorer radiographic clarity, with only 14.1% classified as single point and clear compared with 84.5% for the sella turcica. Interobserver reproducibility was lower for the EAM (ICC: 0.84 horizontal, 0.89 vertical) than for the sella turcica (0.97, 0.95). Horizontal deviation among observers was significantly greater for the EAM (major deviation 6.3 mm vs. 2.2 mm, p < 0.001), whereas vertical deviation did not differ significantly. Conclusions: Although anatomically close to the MNI, the EAM demonstrated inferior radiographic clarity and reproducibility. These findings suggest that the EAM may have limitations as a cranial reference landmark.

PURPOSE:Ossification of the ligamentum flavum (OLF) is known to compress neural structures, leading to myelopathy. Although computed tomography (CT) is a reliable diagnostic tool, thoracic OLF is often underdiagnosed due to the challenges of routinely performing thoracic imaging in clinical practice. Radiographs offer a more accessible option but lack established criteria for screening clinically significant thoracic OLF. MATERIALS AND METHODS:Retrospective study conducted at a single institution, evaluating radiographic and clinical data from patients with thoracic OLF. A total of 142 patients were included: 69 in the myelopathy group, who had myelopathy symptoms due to thoracic OLF, and 73 in the non-myelopathy group, who had OLF observed on CT but no myelopathy symptoms. RESULTS:The OLF diameter (8.39±2.42 mm vs. 5.96±2.93 mm, p<0.001) and OLF diameter ratio (0.63±0.15 vs. 0.42±0.33, p<0.001) were significantly larger in the myelopathy group compared to the non-myelopathy group. Receiver operating characteristic analysis revealed that an OLF diameter ratio ≥0.58 on lateral radiographs had an area under the curve of 0.817, with 73% sensitivity and 82% specificity for predicting myelopathy. CONCLUSION:The OLF diameter ratio measured on lateral radiographs is an effective and non-invasive parameter for identifying thoracic OLF cases with myelopathy symptoms. When the OLF diameter ratio is ≥0.58, clinicians should consider the possibility of myelopathy and perform further diagnostic imaging, such as CT or magnetic resonance imaging, to guide treatment decisions.

Background/Objectives: To evaluate the clinical and radiological outcomes of surgical interventions stratified by dynamic K-line status and to identify predictors of neurological recovery in multilevel cervical ossification of the posterior longitudinal ligament (OPLL). Methods: This study analyzed 535 patients with multilevel cervical OPLL who underwent anterior cervical discectomy and fusion (ACDF), laminoplasty (LP), or laminectomy with fusion (LF), with a minimum 24 months of follow-up. Patients were classified based on dynamic K-line status-neutral (NK-line) and flexion (FK-line)-into three groups: Group 1 (NK-line [+]/FK-line [+]), Group 2 (NK-line [+]/FK-line [-]), and Group 3 (NK-line [-]/FK-line [-]). Radiographic parameters, JOA scores, and VAS were compared, and multivariate regression identified predictors of recovery. A multinomial inverse probability of treatment weighting (IPTW) analysis was conducted to reduce treatment selection bias. Results: Progressive dynamic K-line negativity was associated with greater cervical kyphosis, a higher canal-occupying ratio, reduced FK-line distance, and poorer neurological recovery. After IPTW analysis, ACDF showed higher adjusted recovery across subgroups. In Group 1, younger age and fewer operative levels predicted better recovery. In Groups 2 and 3, LF demonstrated significantly greater neurological recovery than LP. A larger preoperative FK-line distance and a greater postoperative FK-line distance increase were independent predictors of favorable outcomes. Conclusions: Dynamic K-line stratification has good prognostic value in multilevel cervical OPLL. ACDF remains the most effective procedure across dynamic K-line status groups, and LF is preferred over LP in patients with latent or fixed FK-line (-). Incorporating dynamic K-line metrics into surgical planning could improve procedure selection and enhance neurological recovery.

Objective:Intradural extramedullary (IDEM) tumor surgery traditionally focuses on gross total resection (GTR), but postoperative quality of life-specifically chronic axial pain-has emerged as a critical metric. Conventional laminoplasty, despite being restorative, involves bilateral muscle stripping that may cause persistent axial morbidity. Research question:This study investigated whether the unilateral, muscle-preserving approach of hemilaminectomy translates into superior long-term axial pain control compared to laminoplasty. Methods:We retrospectively reviewed 99 patients (Hemilaminectomy: 55; Laminoplasty: 44). To isolate the impact of surgical trauma, cases with significant facet violations or pre-existing instability were excluded. Axial and radiating pain (NRS) were assessed at 1, 6, and 12 months postoperatively. Results:Preoperative disc and facet degeneration were comparable between groups (p > 0.05). While radiating pain relief was equivalent, the hemilaminectomy group showed significantly lower axial pain at 6 months (1.54 ± 1.89 vs. 2.58 ± 1.79, p = 0.002) and 1 year (2.07 ± 2.06 vs. 2.63 ± 1.70, p = 0.049). This benefit was most pronounced in the thoracic subgroup, which showed superior 6-month axial pain control (p = 0.002) and continuous recovery from 1 month to 1 year (p = 0.028) compared to the laminoplasty group. Conclusion:Hemilaminectomy provides a distinct minimally invasive advantage by preserving the posterior midline structures and contralateral muscles. This structural integrity leads to a significant reduction in chronic surgery-induced axial pain compared to laminoplasty, particularly in the thoracic spine.

OBJECTIVE:To evaluate long-term bone quality changes within the fusion construct (FC) after 2- to 3-level lumbar fusion using computed tomography (CT)-derived Hounsfield units (HUs). METHODS:Among 520 screened patients, 222 who underwent 2- to 3-level posterior lumbar interbody fusion met the inclusion criteria. HU values were measured on CT scans preoperatively, at 1-year postoperative, and at final follow-up. The percentage change in HU (HU [final-pre]%) was calculated for each vertebral level. RESULTS:At the final follow-up, the FC demonstrated a significant decline in HU compared to preoperative values (median [10th-90th percentile], 132.0 [86.5-220.4]; 95% confidence interval [CI], 116.0-142.5 vs. 124.5 [71.0- 210.0]; 109.8-135.1; HU (final-pre)%: -11.0 [-62.0 to 48.5]; -19.9 to -6.1; p<0.001). In contrast, HU increased significantly at the uppermost instrumented vertebra (HU (final-pre)%: median [10th-90th percentile], 28.3 [-19.9 to 102.9]; 95% CI, 21.1-36.4; p<0.001), likely reflecting increased mechanical demands. Subgroup analysis revealed a more pronounced decline in HU in patients with longer follow-up durations, particularly in the FC group (p=0.003). CONCLUSION:CT-derived HU revealed progressive trabecular bone loss within FC over time after lumbar fusion. In patients with longer postoperative intervals, clinicians should remain aware of the potential weakening of the FC, which has important implications when considering implant removal or planning revision surgery.

BACKGROUND CONTEXT:Incidental durotomy (IDT) is a frequent intraoperative complication in spine surgery. While most cases are managed successfully with primary repair, management failure leads to persistent symptoms and necessitates secondary intervention, resulting in significantly poorer clinical outcomes. PURPOSE:To identify independent risk factors for management failure following IDT through a comprehensive analysis of patient demographics, pathological conditions, and surgical approaches. STUDY DESIGN/SETTING:A retrospective cohort study at a single tertiary institution. PATIENT SAMPLE:A total of 1,180 patients with confirmed IDT, identified from a continuous series of 24,438 spinal procedures performed between 2011 and 2024. OUTCOME MEASURES:The incidence of IDT and the rate of management failure, defined as the requirement for secondary surgical intervention. METHODS:To evaluate factors contributing to IDT management failure, the cohort was categorized into three distinct surgical subgroups based on the surgical approach used: anterior cervical, posterior thoracic OPLL (ossification of the posterior longitudinal ligament)/OLF (ossification of the ligamentum flavum), and general posterior approaches. A comparative evaluation of clinical, anatomical, and operative variables was performed between the success and failure groups to derive independent predictors of surgical failure. RESULTS:The overall incidence of IDT was 4.8% (1,180/24,438), with a management failure rate of 3.22% (38/1,180). Failure rates varied by procedure, peaking in anterior cervical corpectomy and fusion (13.3%) and posterior thoracic OPLL/OLF surgery (9.5%). In the thoracic OPLL/OLF subgroup, revision surgery (42.9% vs 5.4%, p = 0.015) and a higher OPLL occupying ratio (55.9% vs 16.3%, p < 0.001) were significantly associated with management failure. In minimally invasive procedures, 74.7% of IDTs were successfully managed without primary sutures. In the general posterior approach subgroup, multivariate analysis identified radiotherapy history (OR 14.82, 95% CI 3.12-70.45, p < 0.001), dural patch use (OR 5.32, 95% CI 2.05-13.84, p < 0.001), long-segment surgery (≥ 4 levels) (OR 3.12, 95% CI 1.28-7.62, p = 0.012), and higher body weight (OR 1.04, p = 0.019) as independent predictors of failure. CONCLUSIONS:Management failure after IDT is driven by patient-specific and anatomical factors. High-risk scenarios-specifically previous radiotherapy, revision thoracic procedures, and severe OPLL-starkly increase this risk, necessitating proactive surgical strategies. To prevent secondary interventions, surgeons must move beyond primary repair alone, optimizing the local environment by obliterating anatomical dead space and ensuring adequate extrinsic tamponade.

Background/Objectives: Optimal trajectories for S2-alar-iliac (S2AI) screw placement have been widely studied; however, in fluoroscopy-assisted free-hand techniques, exact reproduction is rarely achievable. This study aimed to quantify direction-specific safety margins around patient-specific optimal trajectories and to determine their relationship with pelvic parameters. Methods: We retrospectively analyzed patients who underwent S2AI screw fixation with available preoperative and postoperative CT imaging. Pelvic parameters, including pelvic tilt (PT), sacral slope (SS), and pelvic incidence (PI), were measured. Optimal transverse and sagittal screw angles were determined using CT-based planning. Postoperative CT was used to assess actual screw trajectories and cortical violations. Direction-specific generalized estimating equation models were used to evaluate associations between trajectory deviation and screw malposition. Receiver operating characteristic (ROC) analysis was performed to determine cutoff values for safe deviation. Results: A total of 62 patients (105 screws) were included in axial analysis and 41 patients (76 screws) in sagittal analysis. PT and PI showed significant inverse correlations with both optimal transverse and sagittal angles (all p < 0.001). Greater lateral and medial deviations were significantly associated with corresponding cortical violations (OR 2.33, 95% CI 1.51-3.59; and OR 2.10, 95% CI 1.40-3.15 per degree, respectively; both p < 0.001). Inferior deviation was significantly associated with violation in the sagittal plane (OR 1.39, 95% CI 1.18-1.65 per degree; p < 0.001), whereas superior deviation was not significant. ROC analysis demonstrated asymmetric safety margins: 1.5° lateral (AUC = 0.972), 8.1° medial (AUC = 0.965), and 18.5° inferior (AUC = 0.897). Conclusions: S2AI screw placement may be conceptualized as a tolerance-based process centered on a patient-specific optimal trajectory. Safety margins are direction-dependent and asymmetric, with a narrow tolerance for lateral deviation. These findings provide practical guidance for intraoperative trajectory adjustment in free-hand techniques.

Background/Objectives: This retrospective study aimed to evaluate the radiologic outcomes and changes in biochemical inflammatory markers following posterior lumbar interbody fusion (PLIF) with Escherichia coli-derived recombinant human bone morphogenetic protein-2 (E.BMP-2), compared with conventional autologous bone grafting. Methods: The study included 112 patients undergoing single- or two-level PLIF for degenerative lumbar disease between 2022 and 2023, divided into E.BMP-2 (n = 50) and Control (n = 62) groups. Radiological outcomes, including Bridwell grading system and adjacent vertebral body (VB) changes, and changes in biochemical inflammatory markers—white blood cell (WBC) count, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and neutrophil count—were assessed. Clinical outcomes were also evaluated. Multivariate regression and propensity-score-matched analyses, and linear mixed-effects models were applied. Results: Fusion rates were comparable between the groups (90.8% vs. 96.7%; p = 0.466); adjusted analyses showed no independent association between E.BMP-2 use and fusion outcomes. The E.BMP-2 group demonstrated a higher prevalence of adjacent VB changes (78.5% vs. 54.3%; p = 0.001), and higher postoperative inflammatory markers including CRP levels on postoperative day 7 and at 1 month, along with increased neutrophil levels on postoperative day 4 (CRP day 7: 31.7 ± 26.4 mg/L vs. 18.7 ± 14.4 mg/L, p = 0.014; CRP 1 month: 7.2 ± 13.0 mg/L vs. 2.7 ± 3.8 mg/L, p = 0.022; neutrophil count day 4: 64.4 ± 10.6% vs. 60.6 ± 8.7%, p = 0.039). However, no significant differences in clinical outcomes, as assessed by VAS scores, were observed according to adjacent VB changes or inflammatory markers. Postoperative fever and infection rates were similar between groups. Conclusions: E.BMP-2 use in PLIF demonstrated fusion rates comparable to those of autografts, without demonstrated superiority. No significant differences in clinical outcomes were identified. Further large-scale prospective studies are needed to clarify its clinical role and optimal dosing.

Study DesignRetrospective cohort study.ObjectivesTo compare the outcomes of C2 dome-like laminoplasty (C2-Dom LP) and C2 laminectomy with fusion (C2-LF) in patients with C2-involving ossification of the posterior longitudinal ligament (OPLL) and to identify radiological predictors that guide optimal surgical selection.MethodsA retrospective analysis of 143 patients (C2-Dom LP, 71; C2-LF, 72) was performed. Radiological evaluations were C2 cross-sectional area (CSA), cervical range of motion (ROM), canal-occupying ratio, and sagittal alignment parameters. Clinical outcomes were assessed using Japanese Orthopedic Association (JOA) scores, neck disability index, and visual analog scale. Subgroup analysis was conducted according to canal compromise severity. A propensity-matched analysis using demographic and perioperative variables was performed to ensure an unbiased comparison.ResultsAfter propensity-matched analysis, C2-Dom LP preserved cervical ROM and sagittal alignment, whereas C2-LF produced substantially greater canal expansion. Both groups demonstrated clinical improvement, but C2-LF achieved a significantly higher JOA recovery rate following matching, highlighting its superior neurological benefit. In the high-compromise subgroup, defined by a CSA cutoff of 92.24 mm2, C2-LF yielded markedly better neurological recovery than C2-Dom LP. Logistic regression identified smaller CSA, larger sagittal vertical axis, and lower baseline JOA score as independent predictors of poorer outcome.ConclusionsC2-Dom LP preserved motion and alignment and can be effective for standard-risk patients. C2-LF achieved greater canal expansion and better recovery in high-compromise patients. A CSA-based, risk-stratified approach could improve with adoption of this threshold, potentially enhancing surgical decision-making and the long-term outcomes of patients with C2 involvement OPLL.

BACKGROUND AND OBJECTIVES:This study compared the surgical outcomes of open-door (OD) and double-door (DD) laminoplasties in patients with cervical ossification of the posterior longitudinal ligament (OPLL). METHODS:This single-center study included 62 patients in the OD group and 47 patients in the DD group, all of whom were evaluated over a 10-year follow-up period. We assessed demographics, surgical levels, occupying ratio, K-line classification, type of OPLL, C2-C7 Cobb angle, cervical OPLL volume, and range of motion (ROM). Clinical outcomes were assessed using visual analog scale score, Japanese Orthopedic Association (JOA) score, and recovery rate. RESULTS:No significant differences were observed in age, sex, symptom duration, comorbidities, K-line type, and canal-occupying ratio. Six patients in each group underwent reoperation. The C2-7 Cobb angle remained similar preoperatively, immediately after surgery, or 2 years after surgery. At the 10-year follow-up, the extension angle and ROM were significantly lower in the DD group, although the overall ROM change from baseline was not significant different. OPLL volume was significantly greater in the OD group at 10 years. The visual analog scale scores for the neck and arm were significantly lower in the DD group than in the OD group immediately after surgery, with no difference between the groups at 10 years postsurgery. The JOA scores showed a similar improvement at 10 years postoperatively. CONCLUSION:Both laminoplasty methods were effective for long-term treatment of cervical OPLL, providing similar clinical outcomes and improvement in the JOA score over a 10-year follow-up period. However, the ROM decreased significantly more in the DD group than in the OD group, especially in patients younger than 50 years of age. These findings suggest that, although both techniques are viable options, patient age and preservation of cervical ROM may be important considerations in the choice of surgical method.

BACKGROUND AND OBJECTIVES:Cervical ossification of the posterior longitudinal ligament (OPLL) is a progressive condition that leads to spinal cord compression, yet clinicians frequently encounter a significant mismatch between radiological severity and clinical symptoms. This study aimed to identify the most reliable radiological predictors of myelopathy in patients with severe cervical OPLL, with a specific focus on spinal cord-based parameters that account for individual anatomic variations. METHODS:We retrospectively reviewed 300 patients with severe cervical OPLL (occupying ratio >50%). Radiological metrics included occupying ratio, space available for the spinal cord, cord compression ratio, compressed spinal cord cross-sectional area, and %decreased spinal cord area (SCA) (percentage reduction from normal area). Myelopathy was defined as a modified Japanese Orthopaedic Association (mJOA) score ≤17. RESULTS:Among all parameters, %decreased SCA demonstrated the highest diagnostic accuracy for myelopathy [area under curve (AUC) 0.904; 95% CI: 0.863-0.941; cutoff: 15.2%; sensitivity 82.3%; specificity 91.8%], significantly outperforming the occupying ratio (AUC 0.717) and space available for the spinal cord (AUC 0.751). For moderate myelopathy (mJOA ≤14), %decreased SCA showed even higher discriminative performance (AUC 0.931, cut-off 16.3%). It also showed the strongest correlation with mJOA (ρ = -0.772, P < .001) and was the most significant independent predictor in multivariate analysis (β = -0.118 per 1% increase; P < .001). In addition, T2 signal change, OPLL morphology, male sex, and increased local range of motion were independent factors associated with myelopathy severity. CONCLUSION:%Decreased SCA is a highly reliable, cord-specific indicator for assessing myelopathy severity in patients with severe cervical OPLL. Our findings suggest that clinical impairment is determined by a combination of cord-based measurements, dynamic factors (range of motion), and intrinsic cord changes, rather than simple bony canal dimensions alone. LEVEL OF EVIDENCE:Class III.

Study Design: This study was a retrospective single-center cohort study.Purpose: This study aimed to compare long-term shunt patency by shunt type (syringo-subarachnoid [SS], syringo-pleural [SP], syringo-peritoneal [SPt]) and disease etiology (post-traumatic, post-infectious, idiopathic) in patients surgically treated for syringomyelia, using Kaplan-Meier survival methodology.Overview of Literature: Syringomyelia shunting carries a well-documented revision burden, but direct comparative survival data across shunt modalities and etiologic subgroups are scarce, particularly from East Asian centers.Methods: We retrospectively analyzed 42 patients (mean age, 47.6±11.8 years; 57.1% male) who underwent syringomyelia shunting at a tertiary neurosurgical center (January 2000–December 2020) with ≥12 months follow-up. Shunt type was classified as SS (n=12), SP (n=16), or SPt (n=14); etiology as post-traumatic (n=24), post-infectious (n=10), idiopathic (n=6), or hemorrhage/tumor-related (n=2). The primary endpoint was shunt revision surgery. Kaplan-Meier analysis, log-rank testing, and Cox proportional hazards regression were performed.Results: Over a median follow-up of 15 months (range, 12 to 184 months), 16 patients (38.1%) underwent shunt revision. Overall 12- and 24-month patency rates were 79.6% and 72.5%, respectively (median shunt survival 72 months). By shunt type, 12-month patency was 75.0% (SS), 81.3% (SP), and 85.7% (SPt); 24-month patency declined to 48.2% for SS while SP and SPt remained at 81.3% and 85.7% (log-rank p=0.248). Post-infectious syringomyelia showed the shortest median shunt survival (36 months) compared with post-traumatic (not reached) and idiopathic (not reached) groups (log-rank p=0.232). No independent predictor of shunt failure was identified on multivariate Cox regression.Conclusion: All three shunting techniques achieve approximately 80% one-year patency. SS may carry a higher long-term occlusion risk. Post-infectious syringomyelia requires closer postoperative surveillance. Larger prospective studies are needed to establish definitive shunt selection criteria.

BACKGROUND:Minimally invasive surgery-transforaminal lumbar interbody fusion (MIS-TLIF) is widely adopted for the treatment of lumbar degenerative disease. Expandable cages are now increasingly used in MIS-TLIF to facilitate disc height restoration in narrow spaces. Despite theoretical advantages, the clinical and radiologic outcomes of expandable cage compared to static cage remain controversial. METHODS:This retrospective study analyzed 151 patients who underwent single-level lumbar MIS-TLIF performed by a single surgeon at a single institution, with more than 1-year follow-up. Static cages were exclusively used from May 2022 to March 2023 (n = 76), and expandable cages from April 2023 to March 2024 (n = 75). The primary outcomes were radiological disc height and lordotic angles. RESULTS:The expandable cage group demonstrated significantly greater postoperative disc height restoration compared to the static cage group at both immediate postoperative periods (10.3 ± 1.2 mm vs. 9.5 ± 1.5 mm, P = 0.003) and at 1-year follow-ups (9.6 ± 1.4 mm vs. 9.0 ± 1.6 mm, P = 0.028). There were no significant differences between the groups in lordotic angles, fusion rates, and clinical outcomes. Various complications were also comparable, other than the incidence of cage subsidence > 3 mm, which was higher in the expandable cage group (14.7% vs. 3.9%, P = 0.047). CONCLUSIONS:Expandable cages in MIS-TLIF demonstrated superior disc height restoration compared to static cages, which were maintained throughout a 1-year follow-up period despite the relatively higher subsidence rate. No significant differences were observed in terms of lordotic angle restoration, clinical outcomes, or fusion rates.

STUDY DESIGN:Retrospective cohort study. SUMMARY OF BACKGROUND DATA:Preoperative identification of intradural extension in nerve sheath tumors (NSTs) is crucial for surgical planning. While MRI is the primary imaging modality, reliable markers distinguishing intra- and extradural (IED) from extradural-only (EDO) NSTs remain uncertain. OBJECTIVE:To assess the diagnostic utility of MRI features in differentiating IED from EDO NSTs. METHODS:Forty-five patients with confirmed IED or EDO NSTs were retrospectively reviewed. Two radiologists analyzed MRI features, including cerebrospinal fluid (CSF) claw sign and candy shape, with interobserver agreement assessed. Fisher's exact test and receiver operating characteristic analysis were performed. RESULTS:Nine cases were IED, and 36 were EDO NSTs. Interobserver agreements of all imaging features between the two radiologists were excellent. IED tumors showed significantly more CSF claw sign and candy shape, and the prediction performance was assessed for these two imaging features. The CSF claw sign showed AUC values of 0.875 and 0.889, while the candy shape showed AUC values of 0.847 and 0.958. CONCLUSION:CSF claw sign and candy shape are useful MRI findings to differentiate between IED and EDO NSTs.

"Purpose: This study aims to develop and implement an economic evaluation using a micro-costing approach to provide a precise and transparent analysis of the direct costs of cystoscopic procedures in Korean hospitals. The study seeks to identify key cost components and evaluate whether current reimbursement rates accurately reflect these direct costs. Materials and Methods: Significant variations in cost items were identified across different studies. An economic evaluation was conducted using a micro-costing methodology for the cost analysis of cystoscopic procedures, developed through literature review, data collection from studies, and expert consultations. Results: Gangnam Severance Hospital (GSH) performed 2,188 cystoscopic procedures, including 1,847 cystoscopies and 341 JJ stent removals, with average costs of $100.8 and $110.6, respectively. At National Health Insurance Service Ilsan Hospital (NHIMC), 1,463 procedures were performed, including 1,167 cystoscopies and 296 JJ stent removals, with average costs of $119.2 and $125.3. Cystoscopy costs at GSH were driven by reprocessing ($45.8, 45.4%) and equipment ($33.1, 32.9%), while NHIMC’s were $52.5 (44.0%) for equipment and $48.7 (40.8%) for reprocessing. Both hospitals incurred financial losses, with NHIS (National Health Insurance Service) covering only about 71.7% and 60.6% of costs for cystoscopy, and 71.0% and 62.7% for JJ stent removal. Conclusions: The significant discrepancy between HIRA (Health Insurance Review & Assessment Service)’s estimated costs and those identified here suggests that current fees for cystoscopic procedures may be underestimated and require reassessment. Given the results, reevaluating these rates is essential to ensure fair compensation for healthcare providers and to deliver optimal patient care."

Objective: We aimed to investigate the incidence of delayed-onset neurological deficits (DONDs), DOND-related reoperation rates following adult spinal deformity (ASD) surgery, and efficacy of transverse process hooks (TPHs) at the uppermost instrumented vertebra (UIV) compared to pedicle screws (PSs).Methods: We included 90 consecutive patients who underwent instrumented fusion from the sacrum to the distal thoracic spine for ASD, with a minimum follow-up of 24 months. Clinical and radiological outcomes were compared between 33 patients in the TPH group and 57 patients in the PS group, using the Scoliosis Research Society-22 Outcomes questionnaire (SRS-22), Medical Outcomes Study Questionnaire Short-Form 36 (SF-36), and various spinal sagittal parameters.Results: While absent in the TPH group, myelopathy occurred in 15.8% of the PS group, wherein 15 patients underwent reoperation. The change in the proximal junctional angle, from the pre- to postoperative assessment, was lower in the TPH group than in the PS group (0.2 vs. 6.6, p=0.002). Postoperative facet degeneration in the PS group progressed more significantly than in the TPH group (0.5 vs. 0.1, p=0.002). Surgical outcomes were comparable for both groups, except for the back visual analogue scale (3.5 vs. 4.1, p=0.010) and SRS-22 domains, including pain and satisfaction (3.3 vs. 2.9, p=0.033; 3.7 vs. 3.3, p=0.041). No intergroup difference was observed in SF-36.Conclusion: Using TPHs at the UIV level can prevent DOND, and thereby prevent postoperative myelopathy that necessitates reoperation; thus, TPHs is preferable over PSs in ASD surgery.

Study Design.A retrospective analysis at a single institution.Objective.This study aimed to determine whether ossification of posterior longitudinal ligament (OPLL) growth in the C1/2 area remains clinically uneventful despite visible radiologic enlargement.Background.In cervical decompressive surgery for OPLL, preserving the C2 lamina is preferred for stability, and the larger spinal canal space above C2 tends to mitigate clinical issues caused by OPLL growth. However, the effects of OPLL progression in the C1/2 segment, which often remains untreated, on patients' clinical outcomes are unclear.Patients and Methods.We enrolled 144 patients with cervical OPLL who underwent decompression surgery between January 2011 and December 2018. The patients were categorized based on whether they underwent a C2 sparing procedure or C2 laminectomy. The primary outcome was radiologic progression of OPLL, defined as a 2 mm increase in sagittal thickness or longitudinal elongation, and its correlation with clinical symptoms.Results.Of the 144 patients, 35 were in the C2 sparing group, and 109 were in the C2 laminectomy group, with an average follow-up period of 5.2 to 5.6 years. The rate of radiologic progression of OPLL in the C1/2 segment was comparable between the two groups (54.3% vs. 51.4%, P = 0.916). However, diagnosis of C1/2 stenosis at the final follow-up was still lower in the C2 sparing group than in the C2 laminectomy group (2.9% vs. 10.1%, P = 0.294), and there were no new cases of symptoms caused by cord compression in the C1/2 segment in either group.Conclusion.OPLL in the C1/2 segment was clinically silent despite radiologic growth. For patients who do not present with significant canal stenosis or cord compression due to OPLL above the C2 upper lamina, C2 lamina-sparing decompressive surgery is preferred.Level of Evidence.Level III.

Utilizing “You only look once” (YOLO) v4 AI offers valuable support in fracture detection and diagnostic decision-making. The purpose of this study was to help doctors to detect and diagnose fractures more accurately and intuitively, with fewer errors. The data accepted into the backbone are diversified through CSPDarkNet-53. Feature maps are extracted using Spatial Pyramid Pooling and a Path Aggregation Network in the neck part. The head part aggregates and generates the final output. All bounding boxes by the YOLO v4 are mapped onto the 3D reconstructed bone images after being resized to match the same region as shown in the 2D CT images. The YOLO v4-based AI model was evaluated through precision–recall (PR) curves and the intersection over union (IoU). Our proposed system facilitated an intuitive display of the fractured area through a distinctive red mask overlaid on the 3D reconstructed bone images. The high average precision values (>0.60) were reported as 0.71 and 0.81 from the PR curves of the tibia and elbow, respectively. The IoU values were calculated as 0.6327 (tibia) and 0.6638 (elbow). When utilized by orthopedic surgeons in real clinical scenarios, this AI-powered 3D diagnosis support system could enable a quick and accurate trauma diagnosis.

STUDY DESIGN:A retrospective analysis at a single institution. OBJECTIVE:This study aimed to determine whether ossification of posterior longitudinal ligament (OPLL) growth in the C1/2 area remains clinically uneventful despite visible radiologic enlargement. BACKGROUND:In cervical decompressive surgery for OPLL, preserving the C2 lamina is preferred for stability, and the larger spinal canal space above C2 tends to mitigate clinical issues caused by OPLL growth. However, the effects of OPLL progression in the C1/2 segment, which often remains untreated, on patients' clinical outcomes are unclear. PATIENTS AND METHODS:We enrolled 144 patients with cervical OPLL who underwent decompression surgery between January 2011 and December 2018. The patients were categorized based on whether they underwent a C2 sparing procedure or C2 laminectomy. The primary outcome was radiologic progression of OPLL, defined as a 2 mm increase in sagittal thickness or longitudinal elongation, and its correlation with clinical symptoms. RESULTS:Of the 144 patients, 35 were in the C2 sparing group, and 109 were in the C2 laminectomy group, with an average follow-up period of 5.2 to 5.6 years. The rate of radiologic progression of OPLL in the C1/2 segment was comparable between the two groups (54.3% vs. 51.4%, P = 0.916). However, diagnosis of C1/2 stenosis at the final follow-up was still lower in the C2 sparing group than in the C2 laminectomy group (2.9% vs. 10.1%, P = 0.294), and there were no new cases of symptoms caused by cord compression in the C1/2 segment in either group. CONCLUSION:OPLL in the C1/2 segment was clinically silent despite radiologic growth. For patients who do not present with significant canal stenosis or cord compression due to OPLL above the C2 upper lamina, C2 lamina-sparing decompressive surgery is preferred. LEVEL OF EVIDENCE:Level III.