Accuracy of a 3-dimensionally printed custom endoscopy port for minimally invasive ventral slot decompression in dogs: A cadaveric study.

OBJECTIVE: To evaluate the accuracy of a 3-dimensionally (3D)-printed custom endoscopy port (3DEP) for minimally invasive cervical ventral slot decompression. STUDY DESIGN: Cadaveric study. ANIMALS: Fifteen cadavers of dogs weighing between 3.1 and 34.4 kg. METHODS: Minimally invasive cervical ventral slots were created using a 3DEP and an endoscopic system at the C3-C4 intervertebral disc space in each dog by 1 experienced and 1 inexperienced surgeon. Postoperative computed tomography was performed to compare the planned and postoperative screw trajectories (angle, entry point, exit point, and length of the screw entering the spinal canal) and quantify slot formation dimensions. RESULTS: Thirty screws were inserted in 30 vertebral bodies. Mean screw angle deviation was less than 2.5°, entry and exit point deviation was less than 1.6 mm, and length of the screw entering the spinal canal was less than 0.6 mm. No differences were identified between the experienced and inexperienced surgeons. Ventral slot length ratio was 30.15 ± 1.86 for the experienced surgeon and 29.38 ± 1.61 for the inexperienced surgeon (p = .372). The mean ventral slot width ratio was 45.60 ± 1.80 for the experienced surgeon and 47.20 ± 1.54 for the inexperienced surgeon (p = .261). CONCLUSION: Screw positioning and creation of ventral slots were accurately performed using the 3DEP by both inexperienced and experienced surgeons. CLINICAL SIGNIFICANCE: The use of a 3DEP for minimally invasive cervical ventral slot decompression may be an alternative to the conventional ventral slot in dogs. Additional studies are needed to evaluate efficacy and safety.

Minimally invasive mini-hemilaminectomy-corpectomy in cadaveric dogs: evaluation of the accuracy and safety of a three-dimensionally printed patient-specific surgical guide.

BACKGROUND: As the frequency of spine surgery increases in the veterinary field, many studies have been conducted on minimally invasive spine surgery (MISS). Although many studies have been conducted on the thoracolumbar spine about MISS in animals, several problems and limitations have emerged regarding this method. Therefore, we developed a three-dimensional (3D) printed patient-specific surgical guide (3DPSSG) using 3D printing technology to overcome these problems. We aimed to evaluate the accuracy and safety of the 3DPSSG in minimally invasive mini-hemilaminectomy-corpectomy (MI-MHC). MI-MHC using 3DPSSG and an endoscopic system was performed at L1-L2 in 15 cadaveric dogs. The procedure of fixing the surgical guide to the vertebral body through screws and the surgical procedure using the guide were performed by two surgeons with different experiences. Postoperative computed tomography was used to measure planned and postoperative screw trajectories (angle, protruding from the far cortex) and to create 3D rendering images of vertebrae to evaluate the direction of bone window formation, corpectomy slot length, depth, and height ratio. RESULTS: The two groups which performed by two surgeons with different experiences did not differ in terms of screw angle deviation and length of the screw protruded from the far cortex. The corpectomy slot-length ratio was not different between the two groups; however, the slot-depth and height ratios were different. CONCLUSIONS: No differences were detected in screw trajectory and corpectomy slot-length ratio between the two groups. The 3DPSSG for MI-MHC is classified as accurate and safe; therefore, it can be an alternative to the conventional technique in dogs.

Evaluation of a customized 3D-printed saw guide for tibial plateau leveling osteotomy: An ex vivo study.

OBJECTIVE: To determine whether a tibial plateau leveling osteotomy (TPLO) performed with a customized 3D-printed guide and jig is more accurate than the traditional technique using a jig alone. STUDY DESIGN: In vitro study. SAMPLE POPULATION: Cadaveric canine pelvic limbs (n = 10) and 20 synthetic bone models. METHODS: Tibial plateau leveling osteotomy using a jig with (n = 10) and without (n = 10) a customized 3D-printed guide were performed in bone models, and TPLO using a jig with (n = 5) and without (n = 5) a customized 3D-printed guide were performed in cadaveric limbs. Angulation of the osteotomy, angulation of the proximal jig pin, angular/torsional deformity and medial cortex damage were measured from photographs of the specimens and compared. RESULTS: In the bone models, there were differences with and without the 3D guide for mean osteotomy inclination (-0.06° vs. -1.74°, P < .001), osteotomy torsion (5268 vs. 10 469 visible osteotomy pixels, P < .001), and medial cortical damage (2970 vs. 18 562 pixels, P < .001). In the cadaveric study, osteotomy inclination (-1.1° vs. 1.01°, P < .01), induced angular deformity (0.17° vs. -3.01°, P < .001) and angulation of the proximal jig pin (-0.27° vs. 0.80°, P < .001) differed between groups. CONCLUSION: The 3D-printed guide during TPLO resulted in slightly more accurate osteotomies and proximal jig pin placement, and reduced medial cortex damage. CLINICAL SIGNIFICANCE: A customized 3D-printed guide may improve intraoperative accuracy for TPLO, although the clinical significance of the small benefits is unknown.

Impaired AKT signaling and lung tumorigenesis by PIERCE1 ablation in KRAS-mutant non-small cell lung cancer.

KRAS-mutant non-small cell lung cancer (NSCLC) is a major lung cancer subtype that leads to many cancer-related deaths worldwide. Although numerous studies on KRAS-mutant type NSCLC have been conducted, new oncogenic or tumor suppressive genes need to be detected because a large proportion of NSCLC patients does not respond to currently used therapeutics. Here, we show the tumor-promoting function of a cell cycle-related protein, PIERCE1, in KRAS-mutant NSCLC. Mechanistically, PIERCE1 depletion inhibits cell growth and AKT phosphorylation (pAKT) at S473, which is particularly observed in KRAS-mutant lung cancers. Analyses of AKT-related genes using microarray, immunoblotting, and real-time quantitative PCR indicated that PIERCE1 negatively regulates the gene expression of the AKT suppressor, TRIB3, through the CHOP pathway, which is a key regulatory pathway for TRIB3 expression. Similarly, in vivo analyses of PIERCE1 depletion in the KRAS mutation-related lung cancer mouse models revealed the suppressive effect of PIERCE1 knockout in urethane- and KRASG12D-induced lung tumorigenesis with decreased pAKT levels observed in the tumors. Tissue microarrays of human lung cancers indicated the expression of PIERCE1 in 83% of lung cancers and its correlation with pAKT expression. Thus, we illustrate how PIERCE1 depletion may serve as a therapeutic strategy against KRAS-mutant NSCLC and propose the clinical benefit of PIERCE1.