Cutaneous Coinfection of Cytomegalovirus and Mycobacterium chelonae Accelerated by Immunosuppression.

A mildly diabetic 58-year-old male had traumatic ulceration on the left popliteal fossa, and the lesion progressed to a painful 6 cm deep ulcer. After surgical debridement and skin grafting, ulceration recurred. Pyoderma gangrenosum was clinically diagnosed after the first biopsy, indicating a noninfective ulcer. Immunosuppressive therapy (prednisolone and cyclosporine A) induced complete epithelialization in three months. Four months later, subcutaneous nonulcerated nodules appeared on the anterior area of the left lower leg. Subcutaneous induration progressed and ulceration recurred, so that immunosuppressive therapy continued for one year. Cytomegalovirus (CMV) viremia was detected, and the second biopsy demonstrated CMV inclusions of endothelial and perivascular cells in fibrosing septolobular panniculitis. Cyclosporine A was cancelled, prednisolone was tapered, and ganciclovir started. Viremia soon disappeared, but the lesion progressed to large induration with multiple ulcers measuring up to 3 cm. The third biopsy disclosed infection of Gram-positive mycobacteria, accompanying fat droplet-centered suppurative granulomas without CMV infection. Microbial culture identified Mycobacterium chelonae. Clarithromycin with thermotherapy was effective. A review of the second biopsy confirmed coinfection of CMV and Gram-positive mycobacteria. Immunostaining using a panel of anti-bacterial antibodies visualized the mycobacteria in the lesion. Positive findings were obtained with antibodies to Bacillus Calmette-Guérin, Bacillus cereus, MPT64 (Mycobacterium tuberculosis-specific 24 kDa secretory antigen), LAM (Mycobacterium tuberculosis-related lipoarabinomannan), and PAB (Propionibacterium acnes-specific lipoteichoic acid).

Paraneoplastic Pemphigus Involving the Respiratory and Gastrointestinal Mucosae.

Paraneoplastic pemphigus (PNP), an autoimmune mucocutaneous disorder involving the oral and bronchial mucosae, is a rare complication of hematologic malignancy. Serologically, serum autoantibodies against varied desmosome-related proteins are of notice. PNP is often lethal due to bronchiolitis obliterans and opportunistic infection. A 70-year-old Japanese male complained of dry cough, stomatitis, and sore throat. The lips and oral mucosa were severely eroded, and skin eruptions were seen on the chest and abdomen. The biopsy features were consistent with PNP, and the deposition of IgG and IgM was shown on the plasma membrane of the involved keratinocytes. Serological studies demonstrated autoantibodies to desmoglein-3, desmocollins-2 and -3, bullous pemphigoid antigen-1, envoplakin and periplakin. Systemic evaluation disclosed mantle cell lymphoma, stage 4B. After chemotherapy, partial remission was reached. PNP was treated with methylprednisolone and intravenous immunoglobulins, and the oral lesion only temporarily responded. He died of respiratory failure two months after onset. Autopsy revealed residual indolent lymphoma and systemic opportunistic infections. Aspergillus colonized the eroded bronchial/bronchiolar mucosa, associated with extensive vascular invasion. Coinfection of cytomegalovirus (CMV) and Pneumocystis jirovecii caused interstitial pneumonia. The oropharyngeal, respiratory, esophageal, and gastrointestinal mucosae were diffusely infected by CMV. Bronchiolitis obliterans was observed in the peripheral lung. PNP-related acantholysis-like lesions were microscopically identified in the bronchial and gastrointestinal mucosa. IgG deposition and cleaved caspase-3-immunoreactive apoptotic cell death were proven in the involved mucosal columnar cells. Pathogenesis of the mucosal involvement is discussed.

New scoring system in assessment of Hoffa's fat pad synovitis: A comparative study with established scoring systems.

AIM: To investigate the reliability of the established and new scoring methods for Hoffa's fat pad synovitis using magnetic resonance imaging (MRI). METHODS: A total of 139 knees of 115 patients who underwent MRI of the knee with and without gadolinium contrast were enrolled in this study. Proton density (PD)-weighted, PD-weighted fat-suppressed (PD-FS), and postcontrast T1-weighted fat-suppressed (T1CE) images were used for evaluation. Using contrast and non-contrast images, our grading method for synovitis was performed to measure synovial thickness and signal intensity changes of the fat pad [Synovial membrane (SM) score], which was compared with the established methods, including MRI Osteoarthritis Knee Score (MOAKS), parapatellar synovitis score, Whole-Organ Magnetic Resonance Imaging Score (WORMS), and suprapatellar effusion diameter. Intraclass correlation coefficients (ICC) for intra and interobserver reproducibility and Spearman correlation coefficients (r) were calculated for the parapatellar synovitis score and each scoring method. RESULTS: All of the scores presented substantial to almost perfect intrareliability. Among three readers, effusion diameter had substantial to almost perfect interreliability (ICC = 0.68-0.81) and WORMS had substantial interreliability (ICC = 0.61-0.70). For two out of three readers, there was substantial interreliability for the thickness score in T1CE (ICC = 0.55-0.69), SM scores in T1CE (ICC = 0.56-0.78) and PD-FS (ICC = 0.51-0.79), and parapatellar synovitis score in T1CE (ICC = 0.53-0.72). The parapatellar synovitis score was significantly correlated with the thickness score in T1CE (r = 0.70) and the SM score in T1CE (r = 0.81) and PD-FS (r = 0.65). CONCLUSION: The newly proposed quantitative thickness score on T1CE and the semi-quantitative SM score on T1CE and PD-FS can be useful for Hoffa's fat pad synovitis.

Assessing patterns of T2/T1rho change in grade 1 cartilage lesions of the distal femur using an angle/layer dependent approach.

PURPOSE: To assess changes in the patterns of T2 and T1rho values within grade 1 cartilage lesions of osteoarthritis (OA) patients compared to healthy controls. MATERIALS AND METHODS: Twenty healthy knees and 25 OA knees were examined on a 3 T scanner. Areas of signal heterogeneity within the cartilage of the distal femur were identified using fat suppressed proton density-weighted imagines. T2 and T1rho values in each OA patient with grade 1 lesions were compared to average T2 and T1rho values of the corresponding areas in healthy subjects. RESULTS: A total of 28 areas including grade 1 lesion were identified. Compared to normal cartilage, the majority of grade 1 cartilage lesions demonstrated either no significant change or a statistically significant increase in both T2 values (18/28, 64%) and T1rho values (23/28, 82%). Compared to T2, T1rho demonstrated a greater proportion of statistically significantly higher values in OA patients than those from the normal controls. However, T2 and T1rho values in grade 1 lesions can be decreased, or demonstrate mixed patterns compared to those in healthy cartilage. CONCLUSION: Our results suggest that early degenerative cartilage lesions can demonstrate various patterns of T2 and T1rho changes.

T1ρ/T2 mapping and histopathology of degenerative cartilage in advanced knee osteoarthritis.

AIM: To investigate whether normal thickness cartilage in osteoarthritic knees demonstrate depletion of proteoglycan or collagen content compared to healthy knees. METHODS: Magnetic resonance (MR) images were acquired from 5 subjects scheduled for total knee arthroplasty (TKA) (mean age 70 years) and 20 young healthy control subjects without knee pain (mean age 28.9 years). MR images of T1ρ mapping, T2 mapping, and fat suppressed proton-density weighted sequences were obtained. Following TKA each condyle was divided into 4 parts (distal medial, posterior medial, distal lateral, posterior lateral) for cartilage analysis. Twenty specimens (bone and cartilage blocks) were examined. For each joint, the degree and extent of cartilage destruction was determined using the Osteoarthritis Research Society International cartilage histopathology assessment system. In magnetic resonance imaging (MRI) analysis, 2 readers performed cartilage segmentation for T1ρ/T2 values and cartilage thickness measurement. RESULTS: Eleven areas in MRI including normal or near normal cartilage thickness were selected. The corresponding histopathological sections demonstrated mild to moderate osteoarthritis (OA). There was no significant difference in cartilage thickness in MRI between control and advanced OA samples [medial distal condyle, P = 0.461; medial posterior condyle (MPC), P = 0.352; lateral distal condyle, P = 0.654; lateral posterior condyle, P = 0.550], suggesting arthritic specimens were morphologically similar to normal or early staged degenerative cartilage. Cartilage T2 and T1ρ values from the MPC were significantly higher among the patients with advanced OA (P = 0.043). For remaining condylar samples there was no statistical difference in T2 and T1ρ values between cases and controls but there was a trend towards higher values in advanced OA patients. CONCLUSION: Though cartilage is morphologically normal or near normal, degenerative changes exist in advanced OA patients. These changes can be detected with T2 and T1ρ MRI techniques.

T1rho and T2 relaxation times of the normal adult knee meniscus at 3T: analysis of zonal differences.

BACKGROUND: Prior studies describe histological and immunohistochemical differences in collagen and proteoglycan content in different meniscal zones. The aim of this study is to evaluate horizontal and vertical zonal differentiation of T1rho and T2 relaxation times of the entire meniscus from volunteers without symptom and imaging abnormality. METHODS: Twenty volunteers age between 19 and 38 who have no knee-related clinical symptoms, and no history of prior knee surgeries were enrolled in this study. Two T1rho mapping (b-FFE T1rho and SPGR T1rho) and T2 mapping images were acquired with a 3.0-T MR scanner. Each meniscus was divided manually into superficial and deep zones for horizontal zonal analysis. The anterior and posterior horns of each meniscus were divided manually into white, red-white and red zones for vertical zonal analysis. Zonal differences of average relaxation times among each zone, and both inter- and intra-observer reproducibility were statistically analyzed. RESULTS: In horizontal zonal analysis, T1rho relaxation times of the superficial zone tended to be higher than those of the deep zone, and this difference was statistically significant in the medial meniscal segments (84.3 ms vs 76.0 ms on b-FFE, p < 0.0001 and 96.5 ms vs 91.7 ms on SPGR, p = 0.004). In vertical zonal analysis, T1rho relaxation times of the white zone tended to be higher than those of the red zone, and this difference was statistically significant in the posterior horn of the medical meniscus (88.4 ms vs 77.1 ms on b-FFE, p < 0.001 and 104.9 ms vs 96.8 ms on SPGR, p =0.001). Likewise, T2 relaxation times of the superficial zone were significantly higher than those of the deep zone (80.4 ms vs 74.4 ms in the medial meniscus, p = 0.011). T2 relaxation times of the white zone were significantly higher than those of the red zone in the medial meniscus posterior horn (96.8 ms vs 84.3 ms, p < 0.001) and lateral meniscus anterior horn (104.6 ms vs 84.2 ms, p < 0.0001). Inter-class and intra-class correlation coefficients were excellent (>0.74) or good (0.60-0.74) in all meniscal segments on both horizontal and vertical zonal analysis, except for inter-class correlation coefficients of the lateral meniscus on SPGR. Compared with SPGR T1rho images, b-FFE T1rho images demonstrated more significant zonal differentiation with higher inter- and intra-observer reproducibility. CONCLUSIONS: There are zonal differences in T1rho and T2 relaxation times of the normal meniscus.

Reliability of MR Quantification of Rotator Cuff Muscle Fatty Degeneration Using a 2-point Dixon Technique in Comparison with the Goutallier Classification: Validation Study by Multiple Readers.

RATIONALE AND OBJECTIVES: Presurgical assessment of fatty degeneration is important in the management of patients with rotator cuff tears. The Goutallier classification is widely accepted as a qualitative scoring system, although it is highly observer-dependent and has poor reproducibility. The objective of this study was to quantify fatty degeneration of the supraspinatus muscle using a 2-point Dixon technique in patients with rotator cuff tears by multiple readers, and to evaluate the reproducibility compared to Goutallier classification. MATERIALS AND METHODS: Two hundred patients with rotator cuff tears who underwent magnetic resonance imaging (MRI), including 2-point Dixon sequence at 3.0-T, were selected retrospectively. Qualitative and quantitative analyses of fatty degeneration were performed by two radiologists and three orthopedic surgeons independently. The fat quantification was performed by measuring signal intensity values of in phase (S(In)) and fat image (S(Fat)), and calculating fat fraction as S(Fat)/S(In). The reproducibility of MR quantification was analyzed by the intra- and interclass correlation coefficients and Bland-Altman plots. RESULTS: The interobserver agreement of the Goutallier classification among five readers was moderate (k = 0.51), whereas the interclass correlation coefficient regarding fat fraction value quantified in 2-point Dixon sequence was excellent (0.893). The mean differences in fat fraction values from the individual segmentation results were from -0.072 to 0.081. Proposed fat fraction grading and Goutallier grading showed similar frequency and distribution in severity of rotator cuff tears. CONCLUSIONS: Fat quantification in the rotator cuff muscles using a 2-point Dixon technique at 3.0-T MRI is highly reproducible and clinically feasible in comparison to the qualitative evaluation using Goutallier classification.

High-resolution MRI of the ulnar and radial collateral ligaments of the wrist.

Background Accurate diagnosis of injuries to the collateral ligaments of the wrist is technically challenging on MRI. Purpose To investigate usefulness of high-resolution two-dimensional (2D) and isotropic three-dimensional (3D) magnetic resonance imaging (MRI) for identifying and classifying the morphology of the ulnar and radial collateral ligaments (UCL and RCL) of the wrist. Material and Methods Thirty-seven participants were evaluated using 3T coronal 2D and isotropic 3D images by two radiologists independently. The UCL was classified into four types: 1a, narrow attachment to the tip of the ulnar styloid (Tip); 1b, broad attachment to the Tip; 2a, narrow attachment to the medial base of the ulnar styloid (Base); and 2b, broad attachment to the Base. The RCL was also classified into four types: 1a, separate radioscaphoid and scaphotrapezial ligaments (RS + ST) with narrow scaphoid attachment; 1b, RS + ST with broad scaphoid attachment; 2a, continuous radio-scapho-trapezial ligaments (RST) with narrow scaphoid attachment; and 2b, RST with broad scaphoid attachment. The inter-observer reliability of these classifications was calculated. Results Type 1a was the most common of both collateral ligaments. Of UCL classifications, 31.4% were revised after additional review of multiplanar reconstruction (MPR) images from isotropic data. The inter-observer reliability of UCL classification was substantial (k = 0.62) without MPR, and almost perfect (k = 0.84) with MPR. The inter-observer reliability of RCL classification was almost perfect (k = 0.89). Anatomic delineation between the two sequences was not statistically different. Conclusion The UCL and RCL were each identified on high-resolution 2D and isotropic 3D MRI equally well. MPR allows accurate identification of the UCL attachment to the ulnar styloid.

Novel, Patient-Specific Instruments for Acetabular Preparation and Cup Placement.

INTRODUCTION: Patient-specific implants and instruments (PSI) have been used in both knee and shoulder replacements due to the perceived benefits of improved surgical accuracy and efficiency. The proposed benefits of using a PSI in total hip arthroplasty (THA) are numerous and include reduction of operative time and improved mechanical and anatomical alignment leading to increased implant longevity, increased stability, and clinical outcomes. We describe a novel patient-specific instrumentation and a surgical method that may improve directed resection of acetabular bone and accurate cup placement during THA. MATERIALS AND METHODS: In this cadaveric study, 14 acetabuli were used. Pre-operative CT or MRI scans were obtained as part of the acetabular jigs Bullseye Hip Replacement Instruments® (Bullseye Hip Replacement, LLC, Las Vegas, Nevada) protocol. Two senior hip surgeons performed all the operations in accordance to the PSI technique. Post-operative CT scans were obtained and acetabular cup orientation was measured by two independent radiologists. RESULTS: Fourteen acetabuli were implanted using the Bullseye Hip Replacement Instruments®. Acetabular cup anteversion angle as measured on post-operative CT images averaged, for all 14 acetabuli, 15.50. Acetabular cup abduction/inclination angle as measured on post-operative CT images averaged 35.9°. All implanted components' size/diameter matched the preoperative surgical planned implant size. CONCLUSION: The Bullseye Hip Replacement Instruments® show good reproducible acetabular cup placement in both anteversion and abduction angles, and accurate sizing of the acetabular component. .

Initial experience with 3D isotropic high-resolution 3 T MR arthrography of the wrist.

BACKGROUND: Our study was performed to evaluate the image quality of 3 T MR wrist arthrograms with attention to ulnar wrist structures, comparing image quality of isotropic 3D proton density fat suppressed turbo spin echo (PDFS TSE) sequence versus standard 2D 3 T sequences as well as comparison with 1.5 T MR arthrograms. METHODS: Eleven consecutive 3 T MR wrist arthrograms were performed and the following sequences evaluated: 3D isotropic PDFS, repetition time/echo time (TR/TE) 1400/28.3 ms, voxel size 0.35x0.35x0.35 mm, acquisition time 5 min; 2D coronal sequences with slice thickness 2 mm: T1 fat suppressed turbo spin echo (T1FS TSE) (TR/TE 600/20 ms); proton density (PD) TSE (TR/TE 3499/27 ms). A 1.5 T group of 18 studies with standard sequences were evaluated for comparison. All MR imaging followed fluoroscopically guided intra-articular injection of dilute gadolinium contrast. Qualitative assessment related to delineation of anatomic structures between 1.5 T and 3 T MR arthrograms was carried out using Mann-Whitney test and the differences in delineation of anatomic structures among each sequence in 3 T group were analyzed with Wilcoxon signed-rank test. Quantitative assessment of mean relative signal intensity (SI) and relative contrast measurements was performed using Wilcoxon signed-rank test. RESULTS: Mean qualitative scores for 3 T sequences were significantly higher than 1.5 T (p < 0.01), with isotropic 3D PDFS sequence having highest mean qualitative scores (p < 0.05). Quantitative analysis demonstrated no significant difference in relative signal intensity among the 3 T sequences. Significant differences were found in relative contrast between fluid-bone and fluid-fat comparing 3D and 2D PDFS (p < 0.01). CONCLUSIONS: 3D isotropic PDFS sequence showed promise in both qualitative and quantitative assessment, suggesting this may be useful for MR wrist arthrograms at 3 T. Primary reasons for diagnostic potential include the ability to make reformations in any obliquity to follow the components of ulnar side wrist structures including triangular fibrocartilage complex. Additionally, isotropic imaging provides thinner slice thickness with less partial volume averaging allowing for identification of subtle injuries.

Acceleration of skeletal age MR examination using compressed sensing.

PURPOSE: To examine the feasibility of accelerating magnetic resonance (MR) image acquisition for children using compressed sensing (CS). Skeletal age assessment using MRI sometimes suffers from motion artifacts because of the long scan time in children. Reducing image acquisition time may provide benefits by reducing motion artifacts, increasing efficiency of examination, and creating a stress-free environment. MATERIALS AND METHODS: Undersampling patterns for CS were optimized and CS-based examination with the acceleration factors of 3 (CS3, 55 seconds per scan) and 4 (CS4, 41 seconds per scan) was performed for 59 subjects (35 boys and 24 girls; mean age, 9.1 years; age range, 4.4-15.3 years) using a 0.3T scanner. The skeletal age was assessed by two raters (A and B). RESULTS: The interrater and intrarater reproducibility in skeletal age assessment was high (Pearson's r = 0.966 [CS3(A1) vs. CS3(A2)], 0.962 [CS4(A1) vs. CS4(A2)], 0.935 [CS3(A1) vs. CS3(B)], and 0.964 [CS4(A1) vs. CS4(B)]; P < 0.001). The errors in skeletal age assessed on the basis of CS-reconstructed images were similar to those assessed on the basis of fully Nyquist-sampled images. CONCLUSION: These results demonstrate the validity and reliability of skeletal age examination accelerated by CS-MRI. We conclude that the acceleration factor of 3 was optimal. J. Magn. Reson. Imaging 2016;44:204-211.

T1rho mapping of entire femoral cartilage using depth- and angle-dependent analysis.

OBJECTIVES: To create and evaluate normalized T1rho profiles of the entire femoral cartilage in healthy subjects with three-dimensional (3D) angle- and depth-dependent analysis. METHODS: T1rho images of the knee from 20 healthy volunteers were acquired on a 3.0-T unit. Cartilage segmentation of the entire femur was performed slice-by-slice by a board-certified radiologist. The T1rho depth/angle-dependent profile was investigated by partitioning cartilage into superficial and deep layers, and angular segmentation in increments of 4° over the length of segmented cartilage. Average T1rho values were calculated with normalized T1rho profiles. Surface maps and 3D graphs were created. RESULTS: T1rho profiles have regional and depth variations, with no significant magic angle effect. Average T1rho values in the superficial layer of the femoral cartilage were higher than those in the deep layer in most locations (p < 0.05). T1rho values in the deep layer of the weight-bearing portions of the medial and lateral condyles were lower than those of the corresponding non-weight-bearing portions (p < 0.05). Surface maps and 3D graphs demonstrated that cartilage T1rho values were not homogeneous over the entire femur. CONCLUSIONS: Normalized T1rho profiles from the entire femoral cartilage will be useful for diagnosing local or early T1rho abnormalities and osteoarthritis in clinical applications. KEY POINTS: • T1rho profiles are not homogeneous over the entire femur. • There is angle- and depth-dependent variation in T1rho profiles. • There is no influence of magic angle effect on T1rho profiles. • Maps/graphs might be useful if several difficulties are solved.

Comparison of T1rho imaging between spoiled gradient echo (SPGR) and balanced steady state free precession (b-FFE) sequence of knee cartilage at 3T MRI.

PURPOSE: To investigate the difference in T1rho profiles of the entire femoral cartilage between SPGR and b-FFE sequences at 3.0T. MATERIALS AND METHODS: 20 healthy volunteers were enrolled in this study. T1rho images of each subject were acquired with two types of pulse sequences: SPGR and b-FFE. Femoral cartilage segmentation was performed by two independent raters slice-by-slice using Matlab. Inter- and intra-observer reproducibility between the two imaging protocols was calculated. The relative signal intensity (SI) of cartilage, subchondral bone marrow, joint effusion, and the relative signal contrast between structures of the knee were quantitatively measured. The difference in T1rho values between SPGR and b-FFE sequences was statistically analyzed using the Wilcoxon signed-rank test. RESULTS: The average T1rho value of the entire femoral cartilage with b-FFE was significantly higher compared to SPGR (p<0.05). The reproducibility of the segmented area and T1rho values was superior with SPGR compared to b-FFE. The inter-class correlation coefficient was 0.846 on SPGR and 0.824 on b-FFE. The intra-class correlation coefficient of T1rho values was 0.878 on SPGR and 0.836 on b-FFE. The two imaging techniques demonstrated different signal and contrast characteristics. The relative SI of fluid was significantly higher on SPGR, while the relative SI of subchondral bone was significantly higher on b-FFE (p<0.001). There were also significant differences in the relative contrast between fluid-cartilage, fluid-subchondral bone, and cartilage-subchondral bone between the two sequences (all p<0.001). CONCLUSION: We need to pay attention to differences in T1rho values between SPGR and b-FFE in clinical applications.

Normal T2 map profile of the entire femoral cartilage using an angle/layer-dependent approach.

PURPOSE: To create standard T2 map profiles from the entire femoral cartilage of healthy volunteers in order to assess regional variations using an angular and layer-dependent approach. MATERIALS AND METHODS: Twenty healthy knees were evaluated using 3T sagittal images of a T2 mapping sequence. Manual segmentation of the entire femoral cartilage was performed slice-by-slice by two raters using MatLab. Inter- and intrarater reliabilities were calculated using intraclass correlation coefficient (ICC) and Bland-Altman analysis. T2 values were analyzed with respect to specific locations (medial condyle, trochlea, and lateral condyle), angles to B0 , and layers of cartilage (whole, deep, and superficial). RESULTS: Inter- and intrarater reliability obtained from the entire femoral cartilage was excellent (ICC = 0.84, 0.86, respectively). The ICCs around the trochlea were lower than those of the medial and lateral condyle. Both the inter- and intrarater Bland-Altman plots indicated larger differences in pixel count are seen as the size of the angular segment becomes larger. T2 values were significantly higher in the superficial layer compared to the deep layer at each femoral compartment (P < 0.001). A magic angle effect was clearly observed, especially within the whole and deep layer over the medial and lateral femoral condyles, except for the superficial layer at the medial condyle. CONCLUSION: The normal T2 map profiles of the entire femoral cartilage showed variations in ICCs by location and in T2 values by angles and layers. These profiles can be useful for diagnosis of early cartilage degeneration in a specific angle and layer of each condyle and trochlea.

A Novel Percutaneous Guide Wire (S-Wire) for Percutaneous Pedicle Screw Insertion: Its Development, Efficacy, and Safety.

PURPOSE: Minimally invasive spine stabilization (MISt) procedures, including MIS-transforaminal lumbar interbody fusion (MIS-TLIF), rely on precise placement of percutaneous pedicle screws (PPS). Serious intraoperative complications associated with PPS placement include great vessel and bowel injuries due to the guide-wire's anterior migration and penetration through the anterior aspect of the vertebral body. To address this issue, we developed a novel percutaneous guide wire (S-wire) and compared the biomechanical characteristics of S-wire and conventional wire in cadaveric spines, and to evaluate the S-wire's efficacy and safety in a clinical trial. METHODS: The S-wire is hollow, with braided wires extending at one tip. We compared the push-out and penetration forces of the S-wire and conventional wire in fresh cadaveric lumbar spines, from L1 to L5. RESULTS: Push-out forces caused the braided tip of the S-wire to bend or spread, and thus to resist anterior migration. The mean push-out forces for the S-wire and conventional wire were 15.5 ± 1.9 and 5.7 ± 0.8 N, respectively (P < .0001); the mean penetration forces were 69.1 ± 4.2 and 37.1± 4.8 N, respectively (P < .0005). There was no wire breakage or anterior-wall penetration in a clinical trial of 922 S-wires; interestingly, the pull-out force increased in 780 (84.6%) S-wires after placement. CONCLUSIONS: The mean push-out and penetration forces for the S-wire were approximately 3 and 2 times greater than those of conventional wire, respectively. The S-wire effectively prevented guide-wire anterior migration and penetration of the anterior vertebral-body wall. The S-wire device should effectively improve the safety of MISt procedures, including MIS-TLIF and percutaneous kyphoplasty in selected patient with osteoporosis.

Morphometric analysis of the lumbar intervertebral foramen in patients with degenerative lumbar scoliosis by multidetector-row computed tomography.

PURPOSE: How the lumbar neural foramina are affected by segmental deformities in patients in whom degenerative lumbar scoliosis (DLS) is unknown. Here, we used multidetector-row computed tomography (MDCT) to measure the morphology of the foramina in three dimensions, which allowed us to elucidate the relationships between foraminal morphology and segmental deformities in DLS. METHODS: In 77 DLS patients (mean age, 69.4) and 19 controls (mean age, 69), the foraminal height (FH), foraminal width (FW), posterior disc height (PDH), interval between the pedicle and superior articular process (P-SAP), and cross-sectional foraminal area (FA) were measured on reconstructed MDCT data, using image-editing software, at the entrance, minimum-area point, and exit of each foramen. The parameters of segmental deformity included the intervertebral wedging angle and anteroposterior and lateral translation rate, measured on radiographs, and the vertebral rotation angle, measured using reconstructed MDCT images. RESULTS: The FH, PDH, P-SAP, and FA were smaller at lower lumbar levels and on the concave side of intervertebral wedging (p < 0.05). In the DLS patients, the FH, P-SAP, and FA were significantly smaller than for the control group at all three foraminal locations and every lumbar level (p < 0.05). Intervertebral wedging strongly decreased the FA of the concave side (p < 0.05). Anteroposterior translation caused the greatest reduction in P-SAP (p < 0.05). Vertebral rotation decreased the P-SAP and FA at the minimum-area point on the same side as the rotation (p < 0.05). CONCLUSION: The new analysis method proposed here is useful for understanding the pathomechanisms of foraminal stenosis in DLS patients.