A novel Patient-Specific Three-Dimensional Printing Template Based on External Fixation for Pelvic Screw Insertion

Does a novel 3D printed individualized guiding template based on cutaneous fiducial markers contribute to accurate percutaneous insertion of pelvic screws? A preliminary phantom and cadaver study

BACKGROUND

Most 3D-printed guiding templates require dissection of soft tissues to match the corresponding surfaces of the guiding templates. This study sought to explore the accuracy and acceptability of the novel 3D printed individualized guiding templates based on cutaneous fiducial markers in minimally invasive screw placement for pelvic fractures.

METHODS

The printed template was tested on five high-fidelity biomimetic phantom models of the bony pelvis and its surrounding soft tissues as well as on two fresh frozen cadavers. Four cutaneous fiducial markers were transfixed on each phantom model prior to performing CT scans to reconstruct their 3D models. Personalized templates for guiding screw insertion were designed based on the positions of the fiducial markers and virtually planned target screw channels after scanning, followed by 3D printing of the guide. Phase 1 consisted of five expert surgeons inserting one anterograde supra-pubic screw and one sacroiliac screw percutaneously into each phantom model using the 3D-printed guide. The deviation of screw positions between the pre-operative planned and post-operative actual ones was measured after registering their 3D modelling. A Likert scale questionnaire was completed by the expert surgeons to assess their satisfaction and acceptability with the guiding template. Phase 2 consisted of repeating the same procedures on the fresh frozen cadavers in order to demonstrate face, content and concurrent validity.

RESULTS

In Phase 1, all ten screws were successfully implanted with the assistance of the guiding template. Postoperative CT scans confirmed that all screws were safely positioned within the bony pelvic channels without breaching the far cortex. The mean longitudinal deviation at the bony entry point and screw tip between the pre-operative planned and post-operative actual screw paths were 2.83 ± 0.60 mm and 3.12 ± 0.81 mm respectively, with a mean angular deviation of 1.25 ± 0.41°. Results from the Likert questionnaire indicated a high level of satisfaction for using the guiding template among surgeons. In Phase 2, results were similar to those in Phase 1.

CONCLUSIONS

The 3D-printed guiding template based on cutaneous fiducial markers shows potential for assisting in the accurate insertion of percutaneous screws in the pelvis.

Clinical application of 3D printing-assisted patient-specific instrument osteotomy guide in stiff clubfoot: preliminary findings

BACKGROUND

The orthopedic treatment of the stiff clubfoot is challenging for clinicians, and the purpose of this study was to explore the preliminary findings of 3D printing-assisted patient-specific instrument (PSI) osteotomy guide for use in the orthopedic treatment of the stiff clubfoot.

MATERIAL AND METHODS

There were 20 patients (25 feet) with stiff clubfoot admitted from December 2018 to June 2022, including 13 males (16 feet) and 7 females (9 feet), aged 24-52 years, mean 40.15 years; 8 left feet, 7 right feet, 5 bipedal. All patients underwent triple arthrodesis and were divided into 10 cases (12 feet) in the PSI group (n = 12) and 10 cases (13 feet) in the conventional surgery group (n = 13) according to the surgical approach. The duration of surgery and the number of radiation exposures were recorded in all cases, and the American Orthopedic Foot and Ankle Society (AOFAS), and International Congenital Clubfoot Study Group (ICFSG) scoring systems were applied postoperatively to assess the effect of corrective treatment. All measurement data were expressed as mean ± standard deviation, and differences between groups were determined by Student's t test. All count data between the two groups were compared using the chi-square test or Fisher's exact test analysis.

RESULTS

All 20 patients (25 feet) were followed up for 1 year. No major complications related to osteotomy, such as overcorrection, incomplete correction, or bone nonunion, were observed in the PSI and conventional surgery groups at the final follow-up, and the PSI group had the advantage of shorter operative time (P < 0.01), less radiation exposure (P < 0.01), and higher excellent rate compared with the conventional surgery group. The AOFAS score (P > 0.05) and ICFSG score (P > 0.05) at the last follow-up were not statistically significant in both groups, but the excellent rate at the last follow-up was 91.7% in the PSI group which was significantly higher than that of the conventional surgery group at 76.9%.

CONCLUSIONS

The utilization of 3D printing-assisted PSI osteotomy guide in orthopedic surgery for stiff clubfoot offers a safe and effective surgical tool for triple joint fusion treatment. This technology simplifies surgical procedures, minimizes intraoperative radiation exposures, reduces surgical time, and enables precise and personalized treatment.

Knockdown of TRIM15 inhibits the activation of hepatic stellate cells

Liver fibrosis is a global public health problem, and the activation of hepatic stellate cells (HSCs) is the main driving force for liver fibrosis. However, the activation mechanism of HSCs is still not fully understood. In this study, we screened out 854 differentially expressed genes [Log₂ fold change absolute: log2 FC(abs) ≥ 1] in activated LX-2 cells. Subsequently, we performed functional analyses of these differentially expressed genes. Gene Ontology enrichment analysis showed that the target genes were mainly enriched in processes such as positive regulation of cell migration involved in sprouting angiogenesis, negative regulation of keratinocyte proliferation, and nuclear inclusion bodies. Kyoto Encyclopedia of Gene and Genome signaling pathway enrichment analysis revealed that dysregulated genes were involved in signaling pathways such as pantothenate and coenzyme A biosynthesis and riboflavin metabolism. The microarray results were validated by reverse transcription-quantitative polymerase chain reaction, which indicated that the microarray results were reliable and that the tripartite motif containing 15 (TRIM15) had the highest absolute value of Log₂FC. Additionally, the effect of TRIM15 on the proliferation, migration, and activation of LX-2 cells was assessed using overexpression plasmids and siRNA transfections. TRIM15 promoted the proliferation and migration of LX-2 cells and positively regulated the expression of α-smooth muscle actin and type I collagen. Collectively, the data revealed the gene expression profiles of quiescent and activated LX-2 cells and the involvement of TRIM15 in the activation of LX-2 cells. Hereby, TRIM15 could be a novel target of the HSC activation mechanism.