An alternative method to evaluate lumbar interbody fusion status focusing on position change of screw-rod constructs.

OBJECTIVES: The evaluation of lumbar interbody fusion status is generally subjective and may differ among raters. The authors examined whether the assessment of position change of screw-rod constructs could be an alternative method for the evaluation of fusion status. METHODS: Sixty-three patients undergoing lumbar interbody single-level fusion were retrospectively reviewed. Three-dimensional images of screw-rod constructs were created from baseline CT examination on the day after surgery and follow-up CT examinations (3-5 months, 6-11 months, and ≥ 12 months) and superposed, with position change of screw-rod constructs being evaluated by the distance between the 3-dimensional images at baseline and follow-up. The evaluation was repeated twice to confirm the reproducibility. Fusion status on follow-up CT examinations was assessed by three raters, where inter-rater reliability was evaluated with Fleiss' kappa. The results of the fusion status were classified into fusion and incomplete fusion groups in each timing of follow-up CT examinations, where the amount of position change was compared between the two groups. RESULTS: The evaluation of position change was completely reproducible. The Fleiss' kappa (agreements) was 0.481 (69.4%). The medians of the amount of position change in fusion and incomplete fusion groups were 0.134 mm and 0.158 mm at 3-5 months (p = 0.21), 0.160 mm and 0.190 mm at 6-11 months (p = 0.02), and 0.156 mm and 0.314 mm at ≥ 12 months (p = 0.004). CONCLUSIONS: The assessment of position change of screw-rod constructs at 6 months or more after surgery can be an alternative method for evaluating lumbar interbody fusion status. KEY POINTS: • Lumbar interbody fusion status (satisfactory, incomplete, or failed) is associated with the quantification of position change of screw-rod in this study. • Reference values for the evaluation of position change in identifying interbody fusion status are provided. • Position change of screw-rod could be a supportive method for evaluating interbody fusion status.

A novel approach to evaluation of lumbar bone density using Hounsfield units in volume of interest on computed tomography imaging.

OBJECTIVE: The purpose of this retrospective study was to evaluate the relationship between bone mineral density (BMD), as assessed with dual-energy x-ray absorptiometry (DEXA), and Hounsfield units (HU) measured in volumes of interest (VOIs) and regions of interest (ROIs) on lumbar spine CT. METHODS: A retrospective analysis was performed on data of lumbar vertebrae obtained from patients who underwent both DEXA and lumbar spine CT scan within a 6-month period. Vertebrae with a history of compression fracture, infectious spondylitis, cement reinforcement, or lumbar surgery were excluded. HU measurements were performed in the VOI and ROI (midaxial, midcoronal, and midsagittal sections) with CT, whereas BMD was assessed with DEXA. Statistical analyses, including correlation assessments and receiver operating characteristic (ROC) curve analyses, were performed. RESULTS: This analysis included 712 lumbar vertebrae, with a median patient age of 72.0 years. BMD values and HU measurements in the VOI increased sequentially from L1 to L4, whereas HU values in the ROI did not show a consistent pattern. HU values in the VOI consistently showed a stronger correlation with BMD than those in the ROI. ROC analysis revealed patient-level cutoff values for the diagnosis of osteoporosis at different lumbar vertebral levels with high sensitivity and specificity, as well as an excellent area under the curve. CONCLUSIONS: This is the first study to introduce a novel approach using the HU value in the VOI to assess bone health at the lumbar spine. There is a strong correlation between the HU value in the VOI and BMD, and the HU value in the VOI can be used to predict osteoporosis.

Prediction of hematoma expansion in spontaneous intracerebral hemorrhage using a multimodal neural network.

Hematoma expansion occasionally occurs in patients with intracerebral hemorrhage (ICH), associating with poor outcome. Multimodal neural networks incorporating convolutional neural network (CNN) analysis of images and neural network analysis of tabular data are known to show promising results in prediction and classification tasks. We aimed to develop a reliable multimodal neural network model that comprehensively analyzes CT images and clinical variables to predict hematoma expansion. We retrospectively enrolled ICH patients at four hospitals between 2017 and 2021, assigning patients from three hospitals to the training and validation dataset and patients from one hospital to the test dataset. Admission CT images and clinical variables were collected. CT findings were evaluated by experts. Three types of models were developed and trained: (1) a CNN model analyzing CT images, (2) a multimodal CNN model analyzing CT images and clinical variables, and (3) a non-CNN model analyzing CT findings and clinical variables with machine learning. The models were evaluated on the test dataset, focusing first on sensitivity and second on area under the receiver operating curve (AUC). Two hundred seventy-three patients (median age, 71 years [59-79]; 159 men) in the training and validation dataset and 106 patients (median age, 70 years [62-82]; 63 men) in the test dataset were included. Sensitivity and AUC of a CNN model were 1.000 (95% confidence interval [CI] 0.768-1.000) and 0.755 (95% CI 0.704-0.807); those of a multimodal CNN model were 1.000 (95% CI 0.768-1.000) and 0.799 (95% CI 0.749-0.849); and those of a non-CNN model were 0.857 (95% CI 0.572-0.982) and 0.733 (95% CI 0.625-0.840). We developed a multimodal neural network model incorporating CNN analysis of CT images and neural network analysis of clinical variables to predict hematoma expansion in ICH. The model was externally validated and showed the best performance of all the models.

Temporal Shape Changes of Pedicle screw-rod Constructs After Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective multicenter study. OBJECTIVE: To examine the shape change of screw-rod constructs over time following short-segment lumbar interbody fusion and to clarify its relationship to clinical characteristics. SUMMARY OF BACKGROUND DATA: No study has focused on the shape change of screw-rod constructs after short-segment fusion and its clinical implications. METHODS: One hundred and eight patients who had single-level lumbar interbody fusion with pedicle screws and cages were enrolled. Three-dimensional (3D) images of screw-rod constructs were generated from baseline CT on the day after surgery and follow-up CT, and were superposed on the right and left side, respectively, using the iterative closest point algorithm. The shape change was quantitatively assessed by computing the median distance between the 3D images, which was defined as the shape change value. Among the five time-course categories of follow-up CT (≤1 month, 2-3 months, 4-6 months, 7-12 months, ≥13 months), the shape change values were compared. The relationships between the shape change values and clinical characteristics, such as age, CT-derived vertebral bone mineral density, screw and rod materials, and postoperative interbody fusion status, cage subsidence, and screw loosening, were evaluated. RESULTS: A total of 237 follow-up CTs were included (≤1 month [34 scans], 2-3 months [33 scans], 4-6 months [80 scans], 7-12 months [48 scans], ≥13 months [42 scans]) because many patients underwent multiple follow-up CTs. There were significant differences in shape change values among the time-course categories (P<0.001 in Kruskal-Wallis test). Most shape changes occurred within 6 months postoperatively, with no significant changes observed at 7 months or more. There were no significant relationships between the shape change values and each clinical characteristic. CONCLUSION: The temporal shape changes of screw-rod constructs following short-segment lumbar interbody fusion progressed up to 6 months after surgery but not significantly thereafter.

Novel Transdural Epiarachnoid Approach for Large Central Disk Herniation in Upper Lumbar Spine.

BACKGROUND AND IMPORTANCE: The treatment for large central disk herniation (LCDH) at upper lumbar spine is often challenging. Previous reports showed various surgical strategies, such as microdiscectomy with posterior fixation, endoscopic surgery, and microdiscectomy through transdural approach. However, there is no consensus regarding which surgical option is better for LCDH at upper lumbar spine. In this report, we describe the novel transdural epiarachnoid approach (TDEA), which uses the corridor of epiarachnoid space for microdiscectomy. Compared with classical transdural approaches, this novel approach may reduce risks of postoperative cerebrospinal fluid leakage and the development of arachnoiditis. CLINICAL PRESENTATION: A 69-yr-old man presented with progressive bilateral radiating leg pain, intermittent claudication, and low back pain. Magnetic resonance images and computed tomography scans revealed LCDH at L2/3 level. We performed microdiscectomy using the TDEA. Postoperative course was uneventful, and his symptoms were relieved after surgery. CONCLUSION: The novel TDEA for LCDH at upper lumbar spine is illustrated with a video. This novel approach has an advantage of the preservation of subarachnoid components compared with classical transdural approaches.

Deep Brain Stimulation in a Patient with Parkinson's Disease and Cortical Superficial Siderosis.

Cortical superficial siderosis (cSS) is a rare condition that is regarded as a potential magnetic resonance marker of cerebral amyloid angiopathy (CAA). We describe the case of a 68-year-old man with cSS and Parkinson's disease (PD) who subsequently exhibited incidental microhemorrhages, which were only detected on magnetic resonance imaging (MRI), at one week after deep brain stimulation (DBS) surgery. cSS is now considered to be a significant risk factor for CAA and future bleeding. Therefore, because DBS surgery is invasive and may increase the risk of intracerebral hemorrhage, the procedure should be performed carefully when managing patients with PD and CAA.

Machine learning prediction of hematoma expansion in acute intracerebral hemorrhage.

To examine whether machine learning (ML) approach can be used to predict hematoma expansion in acute intracerebral hemorrhage (ICH) with accuracy and widespread applicability, we applied ML algorithms to multicenter clinical data and CT findings on admission. Patients with acute ICH from three hospitals (n = 351) and those from another hospital (n = 71) were retrospectively assigned to the development and validation cohorts, respectively. To develop ML predictive models, the k-nearest neighbors (k-NN) algorithm, logistic regression, support vector machines (SVMs), random forests, and XGBoost were applied to the patient data in the development cohort. The models were evaluated for their performance on the patient data in the validation cohort, which was compared with previous scoring methods, the BAT, BRAIN, and 9-point scores. The k-NN algorithm achieved the highest area under the receiver operating characteristic curve (AUC) of 0.790 among all ML models, and the sensitivity, specificity, and accuracy were 0.846, 0.733, and 0.775, respectively. The BRAIN score achieved the highest AUC of 0.676 among all previous scoring methods, which was lower than the k-NN algorithm (p = 0.016). We developed and validated ML predictive models of hematoma expansion in acute ICH. The models demonstrated good predictive ability, showing better performance than the previous scoring methods.

Radiolucent Zone around Screws is Associated with Position Change of Screw-rod Constructs.

PURPOSE: A radiologic assessment method to measure position change of screw-rod constructs over time by superposing the 3­dimensional images assists in quantitative evaluation of screw loosening. We investigated the association between position change and radiolucent zone that was commonly used for diagnosing screw loosening. METHODS: In this study 101 patients who underwent lumbar fusion were reviewed. Patient characteristics included age, sex, indications for surgery, number of fused levels, surgical procedures, and timing of follow-up computed tomography (CT, 1-5 months, 6-11 months, and ≥ 12 months). The Hounsfield unit values of L1 vertebra on preoperative CT were measured, and the radiolucent zone on each follow-up CT was evaluated. Using baseline CT on the day after surgery and follow-up CT, 3­dimensional images of screw-rod constructs were generated and superposed. Position change was assessed by the median of the distances between the 3­dimensional images at baseline and follow-up using the automated measurement method. Patient characteristics, the Hounsfield unit values of L1, and the amount of position change were categorized into the radiolucent zone presence and absence groups and compared. RESULTS: The medians of position change were 0.281 mm and 0.136 mm in the radiolucent zone presence and absence groups, respectively (P < 0.001 by Mann-Whitney U-test). The area under the curve for position change in identifying radiolucent zone was 0.846; the cut-off value was 1.76 mm. In multivariable analysis, position change was independently associated with radiolucent zone (adjusted odds ratio per 0.1 mm, 2.80, 95% confidence interval 1.70-4.61). CONCLUSION: Radiolucent zone was associated with position change of screw-rod constructs.

Intradural Extramedullary Epithelioid Hemangioendothelioma of the Thoracic Spinal Cord: A Case Report.

Epithelioid hemangioendothelioma (EHE) is a rare vascular tumor, and develops infrequently in the central nervous system. To our knowledge, this is the first case of EHE of the spinal cord. An 85-year-old man presented with about 6-month progressive myelopathy. Magnetic resonance imaging (MRI) demonstrated an oval-shaped intradural extramedullary mass at T10 level with extensive intramedullary edema. A reddish tumor was removed via a total laminectomy of T9-T10. Histologically, the tumor cells with nuclear atypia and active mitoses were immunopositive for vascular tumor markers, and formed a lobular architecture associated with capillary-sized vessels lined with edematous endothelial cells. Although very rare, EHE should be considered in the differential diagnosis of a spinal intradural extramedullary tumor.

Intracranial-Intracranial Bypass Using a Y-Shaped Artery Graft for Growing Unruptured Gemella morbillorum Infectious Aneurysm on Artery Supplying Sensory Cortex.

BACKGROUND: Vascular reconstruction is required to treat infectious intracranial aneurysms (IIAs) on arteries supplying the eloquent area. However, extracranial-intracranial bypass is sometimes impossible because IIAs are frequently located distally on arteries and the length of a donor artery is limited. We report a rare case of an unruptured Gemella morbillorum IIA, which was successfully treated by intracranial-intracranial (IC-IC) bypass using a Y-shaped superficial temporal artery (STA) interposition graft. CASE DESCRIPTION: A 52-year-old man presented with heart failure and an unruptured IIA in the right anterior parietal artery because of acute G. morbillorum endocarditis. The patient was treated with urgent replacement of cardiac valves and antibiotic therapy. However, the IIA increased in size during the following 1 month, and therefore was treated surgically to prevent the rupture. End-to-side IC-IC bypass using a Y-shaped STA graft followed by aneurysmal trapping was performed to overcome the limited length of the STA as a donor artery to prevent cerebral ischemia in the artery territory and to avoid direct injury to the sensory cortex adhering tightly to the IIA. Postoperative courses were uneventful, and he recovered from the infectious diseases. CONCLUSIONS: This case suggests that end-to-side IC-IC bypass using a Y-shaped STA graft can be a good option for surgical treatment of IIAs, which are located in eloquent areas.