"Hepatic Superscan" Revealed on 18 F-FDG PET Due to Drug-Induced Fulminant Hepatitis.

ABSTRACT: "Hepatic superscan" could be caused by a variety of etiologies. Here we report a 68-year-old woman with a medication history of cefoperazone and azithromycin for pneumonia recently who underwent 18 F-FDG PET/CT to detect underlying malignancy due to unexplained liver damage and fever of unknown origin. Unexpectedly, "hepatic superscan" without morphologic changes was noted. Unfortunately, aggressive treatment did not reverse the damaged liver function, and the patient rapidly died. Drug-induced fulminant hepatitis was diagnosed clinically. Our case demonstrates that fulminant hepatitis could result in "hepatic superscan" on 18 F-FDG PET despite negative findings on the ultrasonography, CT, and MRI.

A Novel C2 Screw Corridor Parallel to the Sagittal Plane for Transpedicular Fixation - A 3D-CT Study.

STUDY DESIGN: A 3D-CT Study. OBJECTIVE: To research the feasibility and advantages of screw corridors parallel to the sagittal plane (SPC) of the C2 for transpedicular fixation. SUMMARY OF BACKGROUND DATA: A total of 125 patients were enrolled for analysis, and the 3D model of the C2 for the 125 patients were reconstructed and analyzed. METHODS: The SPC screw and the corridor of the general pedicle (GPC) screw of both sides were inserted into these C2 models. The anatomic parameters of the SPC and GPC, including the inner circle diameter, length of the corridors, medial angle and cephalad angle, were measured and compared. The anatomic location of the entry point for the SPC screw was evaluated. RESULTS: The diameter of the SPC averaged 5.5±1.8 mm; 81.2% (203/250) were larger than 4 mm. There was no significant difference between the SPC and GPC in diameter or percentage of diameter greater than 4 mm. There was a significant difference between the length of the SPC (25.3±2.4 mm) and the GPC (27.4±2.2 mm). The cephalad angle was 51.6±6.9° for the SPC and 43.3±4.4° for the GPC, and there was a significant difference between the SPC and GPC. The entry point of the SPC screw was located on the cortical crest at the lower 1/4 of the lamina and located to the lower and inner side of the GPC screw entry point. CONCLUSION: It is feasible for most patients to accommodate an SPC screw with a diameter of 3.5 mm. All SPC screws crossed the pedicle completely. The optimal entry point of the SPC screw was located on the cortical crest of the axial lamina.

Finite Element Analysis and Transiliac-Transsacral Screw Fixation for Posterior Pelvic Ring with Sacrum Dysplasia.

OBJECTIVE: Posterior pelvic ring sacroiliac screws are preferred by clinicians for their good biomechanical performance. However, there are few studies on mechanical analysis and intraoperative screw insertion of the dysplastic sacrum and sacroiliac screw. This study investigated the biomechanical performance of oblique sacroiliac screws (OSS) in S1 combined with transiliac-transsacral screws (TTSs) in S2 for pelvic fracture or sacroiliac dislocation with dysplastic sacrum and evaluated the safety of screw placement assisted by the navigation template. METHODS: Six models were established, including one OSS fixation in the S2 segment, one transverse sacroiliac screw (TSS) fixation in the S2 segment, one TTS fixation in the S2 segment, one OSS fixation in the S1 and S2 segments, one OSS fixation in the S1 segment and one TSS fixation in the S2 segment, one OSS fixation in the S1 segment and one TTS fixation in the S2 segment. Then, finite element analysis (FEA) was performed. Twelve dysplastic sacrum patients with pelvis fracture or sacroiliac dislocation underwent OSS insertion in the S1 combined with TTS insertion in the S2 under the assistance of the patient-specific locked navigation template. Grading and Matta scores were evaluated after surgery. RESULTS: In the one-screw fixation group, the vertical displacements of the sacrum surface of S2 OSS, S2 TSS and S2 TTS were 1.23, 1.42, and 1.22 mm, respectively, and the maximum stress of screw were 139.45 MPa, 144.81 MPa, 126.14 MPa, respectively. In the two-screw fixation group, the vertical displacements of the sacrum surface of the S1 OSS + S2 OSS, S1 OSS + S2 TSS and S1 OSS + S2 TTS were 0.91, 1.06, and 0.75 mm, respectively, and the maximum stress of screw were 149.26 MPa, 167.13 Pa, 136.76 MPa, respectively. Clinically, a total of 12 TTS and OSS were inserted under the assistance of navigation templates, with a surgical time of 55 ± 7.69 min, bleeding of 57.5 ± 18.15 ml and radiation times of 14.5 ± 4.95. One of the TTS and one of the OSS were grade 1, and the other screws were grade 0. The Matta scores of nine patients were excellent, and three patents were good. CONCLUSION: OSS in the S1 combined with TTS in the S2 had the best mechanical stability in six models, and it is safe for screw insertion assisted by the patient-specific locked navigation template.

Custom design and biomechanical clinical trials of 3D-printed polyether ether ketone femoral shaft prosthesis.

During the surgical resection and reconstruction of a pathological femoral fracture, the removal of the femoral tumor leaves a large bone defect. Thus, it is necessary to reconstruct the defect and perform internal fixation. Polyether ether ketone (PEEK) has been widely used in spinal fusion and cranioplasty given its excellent biomechanical properties, biocompatibility, and stability. The typical design method of femoral prosthesis is based on the contralateral mirror image model (M-model), and we propose a novel method for designing femoral prosthesis, which is based on the cross section and centerline of the mirrored femur (C-model). In this study, the femoral shaft prostheses based on two models were manufactured using fused deposition modeling technology, and we use mechanical test and finite element analysis (FEA) to reveal the differences in mechanical properties of the two models. The mechanical results showed that the maximum loading force and yield strength were increased by 3% and 6% in the C-model prosthesis compared with the M-model prosthesis, respectively. In FEA, the results indicate that the C-model prosthesis could reduce the stress concentration by 5.4%-10.9% compared to the M-model prosthesis. Finally, the 3D-printed PEEK femoral shaft prosthesis based on C-model was implanted, no early complications occurred. Postoperative radiological examination indicated that the prosthesis and the femoral osteotomy end were closely matched and fixed well.