Clinical Trial for the Safety and Feasibility of Pedicle Screws Coated with a Fibroblast Growth Factor-2-Apatite Composite Layer for Posterior Cervical Fusion Surgery.

To solve the instrument loosening problem, we developed a fibroblast growth factor-2-calcium phosphate composite layer as a novel coating material to improve screw fixation strength. The primary aim of the present study was to demonstrate the safety and feasibility of screws coated with the FGF-2-calcium phosphate composite layer for posterior instrumented surgery of the cervical spine. The trial design was a single-arm, open-label, safety and feasibility study. Patients receiving fusion of the cervical spine from C2 (or C3) to C7 (or T1) were recruited. The primary endpoint to confirm safety was any screw-related adverse events. Seven patients who underwent posterior fusion surgery of the cervical spine were enrolled in the present study. The coated pedicle screws were inserted bilaterally into the lowest instrumented vertebrae. There was only one severe adverse event unrelated with the coated screw. Three out of the fourteen coated screws showed loosening. The present results prove the safety and feasibility of pedicle screws coated with the FGF-2-calcium phosphate composite layer for fusion surgery in the cervical spine. This is the first step to apply this novel surface coating in the field of spine surgery.

A case report of comminuted trapezium fracture with surgical treatment.

Comminuted trapezium fracture is very rare. As the trapezium is necessary for thumb movements, delayed diagnosis and treatment can result in thumb carpometacarpal (CM) joint osteoarthritis and restricted mobility. The K-wire or screw fixation is recommended for repairing displaced fractures. However, there is currently no established treatment protocol for this rare fracture. In trapezium fracture, a technique with K-wire fixation in addition to open reduction and internal fixation (ORIF) has been reported with favorable clinical outcomes. In this report, we present a case of comminuted trapezium fracture successfully treated with surgery. The present case involved a 26-year-old woman who was injured while driving her car, which led to a comminuted trapezium fracture. ORIF was conducted with headless screws and a locking plate, and the first and second metacarpals were temporarily fixed by K-wire with the thumb in traction. Six months after surgery, bony union and favorable clinical outcomes were achieved. This technique could be beneficial to prevent articular surface collapse in the comminuted trapezium fracture and to achieve favorable clinical outcomes.

Preoperative Predictions of Distal Screw Length for the Osteosynthesis of Distal Radius Fractures.

Background: The objective of this study was to clarify whether anteroposterior dimension of the radius along the screw axis of a fixed angle volar locking plate (VLP) can be predicted from the width of the radius on the VLP. Methods: Sixty-nine wrists in 68 patients with distal radius fractures that underwent fixation with a fixed angle VLPs were evaluated. All patients underwent pre- and postoperative computed tomographic scans of the distal radius. The transverse width of the radius was measured at the position of the third screw hole from the proximal edge. The anteroposterior dimension of the radius (R) was measured along the axes of the distal screws. The distal row screw holes were defined as R1, R2, R3, and R4 from the radial to the ulnar side. Correlation analysis between the width and the anteroposterior dimension, and single regression analysis were performed for each screw hole. The correlations amongst the R values for the different distal row screws were also assessed. Results: The correlation coefficients between the transverse width and anteroposterior dimensions were 0.54, 0.58, 0.55, and 0.42 for R1, R2, R3, and R4 respectively (p < 0.05). The regression equations were R1 = 0.49W + 7.99, R2 = 0.47W + 11.8, R3 = 0.52W + 10.8, and R4 = 0.41W + 11.5 respectively. The correlation coefficients among anteroposterior dimensions were 0.85, 0.64, 0.59, 0.70, 0.61, and 0.80 for R1/R2, R1/R3, R1/R4, R2/R3, R2/R4, and R3/R4 respectively (p < 0.01). Conclusions: There were significant correlations in the anteroposterior dimensions amongst the distal row screw lengths. The regression equations used in this study may be helpful to predict the length of distal row screw and prevent complications due to inappropriate screw choices. Level of Evidence: Level III (Therapeutic).

Preoperative Evaluation and Surgical Simulation for Osteochondritis Dissecans of the Elbow Using Three-Dimensional MRI-CT Image Fusion Images.

We used our novel three-dimensional magnetic resonance imaging-computed tomography fusion images (3D MRI-CT fusion images; MCFIs) for detailed preoperative lesion evaluation and surgical simulation in osteochondritis dissecans (OCD) of the elbow. Herein, we introduce our procedure and report the findings of the assessment of its utility. We enrolled 16 men (mean age: 14.0 years) and performed preoperative MRI using 7 kg axial traction with a 3-Tesla imager and CT. Three-dimensional-MRI models of the humerus and articular cartilage and a 3D-CT model of the humerus were constructed. We created MCFIs using both models. We validated the findings obtained from the MCFIs and intraoperative findings using the following items: articular cartilage fissures and defects, articular surface deformities, vertical and horizontal lesion diameters, the International Cartilage Repair Society (ICRS) classification, and surgical procedures. The MCFIs accurately reproduced the lesions and correctly matched the ICRS classification in 93.5% of cases. Surgery was performed as simulated in all cases. Preoperatively measured lesion diameters exhibited no significant differences compared to the intraoperative measurements. MCFIs were useful in the evaluation of OCD lesions and detailed preoperative surgical simulation through accurate reproduction of 3D structural details of the lesions.

Novel method for selecting slices of the same cross-sectional view from digital tomosynthesis for monitoring posterior spinal instrumentation.

BACKGROUND: A method to evaluate pedicle screw loosening on digital tomosynthesis images is yet to be established owing to lack of methods for selecting slices of the same cross-sectional view. We aimed to develop an objective method for selecting slices of the same cross-sectional view on digital tomosynthesis images. METHODS: First, an objective method of pixel selection was developed by measuring the size of glass disk and titanium alloy screw on digital tomosynthesis images followed by comparison with the actual sizes. Second, a method for selecting slices of the same cross-sectional view was explored on a bone model with posterior spinal instrumentation using the screw centerline and rod curvature as indicators of the same cross section. The angle between the screw centerline and rod was calculated to verify the accuracy in obtaining the same cross-sectional view. Third, the method for selecting slices of the same cross-sectional view was applied to six patients after posterior lumbar spinal instrumentation. RESULTS: The pixel selection method enabled objective determination of a pixel on the peripheral lines of objects with an error as low as 200 µm in distance measurements on titanium alloy and glass. The mean differences of rod-screw angles between two slices were less than 1° and were not statistically significant in the bone model and patient images. CONCLUSION: A method for selecting slices of the same cross-sectional view on digital tomosynthesis images was successfully developed. This method can enable objective and quantitative evaluations of pedicle screw loosening.

An image fusion system for corrective osteotomy of distal radius malunion.

BACKGROUND: To provide surgical support for corrective osteotomy, we developed an image fusion system for three-dimensional (3D) preoperative planning and fluoroscopy. To assess the utility of this image fusion system, we evaluated the reproducibility of preoperative planning for corrective osteotomy of dorsally angulated distal radius malunion using the system and compared reproducibility without using the system. METHODS: Ten wrists from 10 distal radius malunion patients who underwent corrective osteotomy were evaluated. 3D preoperative planning and the image fusion system were used for the image fusion group (n = 5). Only 3D preoperative planning was used for the control group (n = 5). 3D preoperative planning was performed for both groups in order to assess reduction, placement, and the choice of implants. In the image fusion group, the outline of the planned image was displayed on a monitor and overlapped with fluoroscopy images during surgery. Reproducibility was evaluated using preoperative plan and postoperative 3D images. Images were compared with the 3D coordinates of the radial styloid process (1), the volar and dorsal edges of the sigmoid notch (2) (3), and the barycentric coordinates of the three reference points. The reproducibility of the preoperative plan was evaluated by the distance of the coordinates between the plan and postoperative images for the reference points. RESULTS: The distances between preoperative planning and postoperative reduction in the image fusion group were 2.1 ± 1.1 mm, 1.8 ± 0.7 mm, 1.9 ± 0.9 mm, and 1.4 ± 0.7 mm for reference points (1), (2), (3), and the barycenter, respectively. The distances between preoperative planning and postoperative reduction in the control group were 3.7 ± 1.0 mm, 2.8 ± 2.0 mm, 1.7 ± 0.8 mm, and 1.8 ± 1.2 mm for reference points (1), (2), (3), and the barycenter, respectively. The difference in reference point (1) was significantly smaller in the image fusion group than in the control group (P < 0.05). CONCLUSION: Corrective osteotomy using an image fusion system will become a new surgical support method for fracture malunion. Trial registration Registered as NCT03764501 at ClinicalTrials.gov.

Computer-Aided Assessment of Displacement and Reduction of Distal Radius Fractures.

This study aims to investigate displacements and reductions of distal radius fractures using measurement indices based on the computer-aided three-dimensional (3D) radius shape model. Fifty-two distal radius fracture patients who underwent osteosynthesis were evaluated with pre- and post-operative distal radius 3D images. In the 3D images, three reference points, i.e., the radial styloid process (1), sigmoid notch volar, and dorsal edge (2) (3) were marked. The three-dimensional coordinates of each reference point and the barycentric coordinates of the plane connecting the three reference points were evaluated. The distance and direction moved, due to the reductions for each reference point, were (1) 12.1 ± 8.1 mm in the ulnar-palmar-distal direction, (2) 7.5 ± 4.1 mm in the ulnar-palmar-proximal direction, and (3) 8.2 ± 4.7 mm in the ulnar-palmar-distal direction relative to the preoperative position. The barycentric coordinate moved 8.4 ± 5.3 mm in the ulnar-palmar-distal direction compared to the preoperative position. This analyzing method will be helpful to understand the three-dimensional direction and the extent of displacements in distal radius fractures.

A novel three-dimensional MRI-CT image fusion technique for precise preoperative evaluation and treatment of capitellar osteochondritis dissecans.

OBJECTIVES: We developed a novel method to create three-dimensional magnetic resonance imaging-CT (3D MRI-CT) fusion images for detailed lesion evaluation and surgical simulation in capitellar osteochondritis dissecans (COCD). This study aimed to clarify its usefulness. METHODS: We enrolled 12 boys with COCD (mean age, 13.8 years) and preoperatively constructed 3D models of the humerus and articular cartilage from MR images obtained with a 3-T imager. For better visualization of the articular cartilage outline, we applied 7 kg of axial traction to the elbow during MRI. We also constructed a 3D model of the humerus from CT images. 3D MRI-CT fusion images were created using both models. The average distance difference between two corresponding points as per the 3D CT and 3D MRI models of the humerus was evaluated. Using the 3D MRI-CT fusion images, we measured longitudinal and transverse lesion diameters; evaluated articular cartilage fissures and defects, articular surface deformities, and the International Cartilage Repair Society (ICRS) classification; and validated the results using intraoperative findings. RESULTS: The mean average distance difference was 0.75 mm. The 3D MRI-CT fusion images accurately reproduced lesion conditions in every case and correctly predicted the ICRS classification with 100% accuracy. Preoperatively measured longitudinal and transverse lesion diameters were not significantly different from intraoperative measurements (p = 0.79, 0.32 respectively). CONCLUSION: 3D MRI-CT fusion images provide a detailed evaluation of COCD lesion severity by presenting the exact positional relationship between the articular cartilage and subchondral bone. KEY POINTS: • We developed a novel method to create three-dimensional magnetic resonance imaging-computed tomography (3D MRI-CT) fusion images for the evaluation of capitellar osteochondritis dissecans. • 3D MRI-CT fusion images enabled the accurate prediction of lesions and provided a detailed evaluation of lesion severity by presenting the exact positional relationship between the articular cartilage and subchondral bone.

Utility of an image fusion system for 3D preoperative planning and fluoroscopy in the osteosynthesis of distal radius fractures.

BACKGROUND: Recently, computerized virtual surgery planning has been increasingly applied in various orthopedic procedures. In this study, we developed an image fusion system for 3D preoperative planning and fluoroscopy for the osteosynthesis. To assess the utility of image fusion system, we evaluated the reproducibility of preoperative planning in the osteosynthesis of distal radius fractures with using the image fusion system, and compared with the reproducibility of the patients without using the image fusion system. METHODS: Forty-two wrists of 42 distal radius fracture patients who underwent osteosynthesis using volar locking plates were evaluated. The patients were divided into two groups. Image fusion group utilized three-dimensional (3D) preoperative planning and image fusion system. Control group utilized only 3D preoperative planning. In both groups, 3D preoperative planning was performed in order to determine reduction, placement, and choice of implants. In the image fusion group, the outline of planned image was displayed on a monitor overlapping with fluoroscopy images during surgery. Reductions were evaluated by volar tilt and radial inclination of 3D images. Plate positions were evaluated with distance to joint surface, plate center axis position, and inclination relative to the radius axis. Screw choices were recorded for the plan and actual choices for each screw hole. Differences in the parameters between pre- and postoperative images were evaluated. Differences in reduction shape, plate positions, and screw choices were compared between groups. RESULTS: The differences in the distance from plate to joint surface were significantly smaller in the image fusion group compared to the control group (P < 0.01). The differences in the distal screw choices were significantly smaller in the image fusion group compared to the control group (P < 0.01). CONCLUSIONS: The image fusion system was useful to reproduce the planned plate position and distal screw choices in the osteosynthesis of distal radius fractures. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03764501.

A Comparison of Radiographic Outcomes between 3D Preoperative Planning and Conventional Planning in the Osteosynthesis of Distal Radius Fractures.

Background: To assess the usefulness of three-dimensional (3D) digital pre-operative planning, we compared the radiographic parameters of the distal radius from 3D planning and conventional planning after osteosynthesis of distal radius fractures. We hypothesized that the use of 3D digital planning may improve radiographic outcomes for reduction and decrease the risk of correction loss. Methods: Sixty wrists of 60 distal radius fracture patients were randomly divided into two groups according to the order of hospital visits. Thirty wrists were treated with 3D preoperative planning as the plan group. Another thirty wrists were treated with conventional preoperative planning as the control group. Both groups were treated with volar locking plates. In the plan group, 3D digital preoperative planning and a surgical simulation were performed in order to determine the reduction and placement of the implants in addition to the plate/screw size prior to surgery. In the control group, conventional preoperative planning was performed. Ulnar variance, volar tilt, and radial inclination were measured at one week, three and six months after surgery. Difference of the measurement of radiographic parameters between operated and healthy side wrists were compared between plan and control groups at one week after surgery. Loss of corrections for radiographic parameters were compared between plan and control groups. Results: The differences between the operated and healthy side wrists were significantly smaller in the plan group compared to the control group for the volar tilt and radial inclination (p < 0.05).The loss of corrections for ulnar variance and volar tilt were significantly smaller in the plan group compared to the control group at six months after surgery (p < 0.05). Conclusions: 3D preoperative planning offers better reduction accuracy and reduces correction loss in the osteosynthesis of distal radius fractures.

Screw Length Optimization of a Volar Locking Plate Using Three Dimensional Preoperative Planning in Distal Radius Fractures.

BACKGROUND: A three-dimensional (3D) digital pre-operative planning system for the osteosynthesis of distal radius fracture was developed. The objective of this study was to evaluate screw choices for three-dimensional (3D) digital pre-operative planning of osteosynthesis of distal radius fractures and to compare with the screw choices for the conventional method. METHODS: Distal radius fracture patients who underwent osteosynthesis using volar locking plates were evaluated. Thirty wrists in the plan group utilized 3D preoperative planning, and nineteen wrists in the control group utilized conventional preoperative assessment. In the plan group, the 3D preoperative planning was performed prior to surgery. The reduction was simulated with 3D image, and the implant choice/placement also simulated on the 3D image. In the control group, standard preoperative planning was performed using posterior-anterior and lateral view radiographs, and CT scan. After the planning, osteosynthesis was performed. During the surgery, the operator performed the reduction and the placement of the plate while comparing images between the pre-operative plan and fluoroscopy. The distal screw lengths and the anteroposterior diameter of the radius along the axis of the distal screws were measured. The ratios of the screw length and radius diameter were evaluated. The screw/radius ratios within the range of 0.75-1.00 were considered appropriate. The screw choices less than 0.75, or greater than 1.00 were considered inappropriate. The rate of appropriate screw choices were compared between plan and control groups. RESULTS: The results of appropriate screw choices were 86.1% and 74.8% in the plan group and the control group, respectively. The inappropriate screw choices were 14.0% and 25.2% in the plan group and the control group, respectively. The three-dimensional planning significantly increased appropriate screw choices compared to the conventional planning (p < 0.05). CONCLUSIONS: Three-dimensional digital preoperative planning is useful for the optimization of screw lengths in osteosynthesis of distal radius fractures.

Trapezium Fracture Associated with Thumb Carpometacarpal Joint Dislocation: A Report of Three Cases and Literature Review.

Isolated trapezium fracture in combination with thumb carpometacarpal (CMC) joint dislocation is extremely rare, and no treatment consensus exists. Herein, we report 3 successfully treated cases of isolated trapezium fracture with thumb CMC joint dislocation. While good short-term results have been reported in the literature, the possibility of substantial ligament injuries that can lead to future instability of the thumb CMC joint must be noted. In order to obtain an excellent long-term clinical result, we propose the consideration of the anatomical repair of the CMC joint in terms of both bony and ligamentous structures in cases where instability remains after fracture fixation.