Minimally Invasive Plate Osteosynthesis (MIPO) of Comminuted Radial Fractures Using a Locking Plate Contoured on a 3D-Printed Model of the Feline Antebrachium: A Cadaveric Study.

(1) Background: Due to the unique structural and functional characteristics of the forelimb in cats, fractures of the radius and ulna are best repaired using internal fixation and stabilization in accordance with AO principles. This study presents the results of reduction of 42 cadaveric comminuted feline radial fractures reduced by minimally invasive plate osteosynthesis (MIPO). (2) Methods: Radius fractures were created on 21 pairs of forelimbs with intact bones. MIPO was then performed using two locking bone plates pre-contoured on 3D-printed bone models of the antebrachium of a male and a female cat. Pre- and postoperative radiographs were taken, and radius length and anatomical lateral distal radial angle (aLDRA) were measured. (3) Results: All fractures were classified as complex diaphyseal fractures of the radius. The radial bone length did not change significantly after surgery (F1,18 = 0.01, p = 0.933). However, the aLDRA was modified after surgery (F1,18 = 7.51, p = 0.013), but this change was only observed in females, in whom the aLDRA was significantly reduced (p = 0.035) compared to the value determined by the shape of the plate. In males, the pre- and postoperative aLDRA values were similar (p = 0.824). In 40 cases, alignment, adjacency of bone fragments, and apparatus were judged to be satisfactory. In two cases, the plate was fixed to the proximal radius and distal ulna due to misidentification of the distal radius. In both cases, revision surgery and correct fixation of the radius gave proper alignment, adjacency, and apparatus. (4) Conclusion: A pre-contoured plate on a 3D-printed model of the male and female domestic cat antebrachium was suitable for the reduction and stabilization of comminuted radial fractures in a cohort of domestic cat cadavers without the need to print individual antebrachial bone models for each patient.

A 3D Printed Anatomically Pre-Contoured Plate for the Treatment of Y-T Humeral Condylar Fractures: A Feline Cadaveric Study.

(1) Background: Anatomically pre-contoured plates usually require only minimal or even no intraoperative contouring. For complex cases, such plates also assist the surgeon as an anatomical template during fracture reduction. In this study, we present our experience of using a 3D printing technology for the treatment of bicondylar humeral fractures in feline cadavers. (2) Methods: Surgeries were performed on 15 pairs of front limbs amputated at the scapula. The limbs were obtained from 15 adult cats without obvious pathology of the skeleton. After flexion of the elbow and subperiosteal elevation of the anconeus muscle, the humeral Y-T fractures were created using a bone chisel and mallet. A custom-made anatomically pre-contoured interlocking plate was used to reduce and stabilise the medial aspect of the humeral condyle to the humeral diaphysis. After reduction of the humeral condyle, a positional locking screw was then inserted from the medial to the lateral side and a straight 2.4/2.7 interlocking bone plate was used to stabilise the lateral part of the condyle to the humeral diaphysis. (3) Results: The length of the humerus ranged from 98.2 to 107.0 mm and did not differ significantly between the left and right bone. The diameter of the isthmus of the humeral condyle ranged from 5.2 to 5.5 mm and did not differ significantly between the left and right bone. In all 30 limbs, bicondylar fracture was accompanied by epicondylar comminution. In 7/30 limbs (4 left, 3 right) the fracture of the humeral shaft was also present. In the left limbs, the postoperative articular surface defect of the humeral condyle was small (<1 mm) in 11/15 cases, moderate (1-2 mm) in 2/15 cases and large (>2 mm) in 2/15 cases in which the condylar screw was incorrectly inserted. In the right limbs, the postoperative articular surface defect of the humeral condyle was small (<1 mm) in 14/15 cases and moderate (1-2 mm) in 1 case. (4) Conclusions: 3D printing and the technology of metal powder sintering offers a wide range of possibilities for the development of new surgical implants. The anatomically pre-contoured bone plate appears to be a valuable tool in the reduction and stabilisation of Y-T humeral fractures in adult domestic cats weighing 3.0 to 4.5 kg.

Accuracy of Instrument Portal Placement Using a Custom-Made 3D-Printed Aiming Device versus Free Hand Technique in Canine Elbow Arthroscopy.

While the insertion of the arthroscope into the elbow joint is relatively easy based on anatomical landmarks, obtaining a correctly located instrument portal is often difficult. Therefore, the goal of the study was to create a 3D-printed prototype of an aiming device for the guiding needle, and to check its feasibility. The study included fresh cadavers of 15 dogs, 9 males and 6 females, aged from 1 to 6 years (median 4 years) with body weight from 17 to 57 kg (median 30 kg). On each dog, we compared the number of attempts needed to obtain optimal direction of the guiding needle for the portal, using one elbow the prototype, and performing this as control on the opposite joint without the prototype (with a free hand). The number of attempts needed was significantly lower using the prototype (median 1) than on the control elbows (median 2, p = 0.009). The number of attempts was not correlated with the body weight neither in the case of experimental (Rs = 0.18, p = 0.532) nor control elbows (Rs = 0.13, p = 0.642). We conclude that the used prototype seems to be helpful in elbow joint arthroscopy.

Comparison of the Ventral Approach to the Canine Hip Joint Using Gelpi Retractors and an Elastic O-Ring Wound Retractor.

This study included 10 fresh adult cadavers of large breed dogs (6 males and 4 females). Their weight ranged from 25 to 45 kg (mean ± SD: 33.9 ± 6.2 kg). The breeds represented were crossbreed dogs (n = 5), German shepherds (n = 2), Bernese mountain dogs (n = 1), American Staffordshire terriers (n = 1), and Gordon setters (n = 1). Access to the target area and identification of the femoral head and neck was achieved with two Gelpi retractors inserted orthogonally and with the O-WR in all procedures. In each dog, the approach to the hip joint was made on the left and right sides. There was no significant difference in the area of the surgical wound bed between the two sides using either the Gelpi retractors (-0.52 ± 1.87 cm2; CI 95%: -1.86, 0.81 cm2; p = 0.398) or the O-WR (-0.27 ± 2.34 cm2; CI 95%: -1.94, 1.41 cm2; p = 0.729). The area of the surgical wound bed was 6.28 ± 1.72 cm2 (2.72-9.70 cm2) for the Gelpi retractors and 6.34 ± 1.81 cm2 (4.13-10.77 cm2) for the O-WR, and the difference between the Gelpi retractors and the O-WR was not significant (-0.06 ± 1.72 cm2; CI 95%: -0.86, 0.74 cm2; p = 0.879).

Three-Dimensional Models of Liver Vessels for Navigation during Laparotomic Attenuation of Intrahepatic Portosystemic Shunt in Dogs.

Laparotomic attenuation of an intrahepatic portosystemic shunt (IHPSS) is more difficult than an extrahepatic one, and results in a higher risk of complications because the identification of the aberrant vessel in the liver remains often a challenge. Excessive preparation and traction of the parenchyma results in trauma, bleeding, and prolonged surgery, which is what worsens the prognosis. Therefore, based on computed tomographic angiography, we printed 3-dimensional (3D) individual patient liver models, scaled 1:1, and used them for surgery planning and as a guide during intraoperative identification of the shunt in four dogs with IHPSS. The advantages of the 3D technology are simple and precise planning of the surgery, fast intraoperative identification of the shunt, and low invasive dissection of the liver parenchyma. We conclude that 3D technology can potentially raise the recovery rate. To the best of our knowledge, this was the first application of 3D models in the surgery of canine IHPSS.

Comparison of the Visibility of Canine Menisci before and after Tibial Plateau Leveling Osteotomy: 3D-Printed Model Study.

The aim of this study was to compare the degree of visibility of the lateral and medial menisci before and after tibial plateau leveling osteotomy (TPLO) on 3D-printed models created after laser scanning of the right tibia with menisci derived from a fresh cadaver of a 4-year-old adult male golden retriever. The models were produced of white polylactic acid, and the menisci were filled with light-curing red resin. The models showed a similar conformation as the natural specimen harvested from the cadaver, maintaining the same length and width, in addition to reproducing the anatomical structures. From the pre- and post-TPLO radiographs, it was possible to identify the anatomical structures corresponding to the tibial plateau. The preoperative tibial plateau angle was 26.2°, and the postoperative one ranged between 4.0° and 5.3° (4.6 ± 0.4°). In the bird's-eye photo, the total number of red pixels in the lateral and the medial meniscus was 2,053,995 and 2,140,939, respectively. Before TPLO, only between 14% and 19% of the entire area of the menisci was visible, and the unhidden part of the entire area of the meniscus before TPLO did not differ significantly between the lateral (16.2 ± 1.6%) and the medial (16.4 ± 1.6%) meniscus (p = 0.351). The visible part of the entire meniscus area increased significantly after TPLO both in the lateral and medial menisci (p < 0.001)-mean difference ± SD of 30.3 ± 4.3% (CI 95%: 27.9%, 32.6%) and 36.4 ± 6.4% (CI 95%: 32.9%, 40.0%), respectively. In conclusion, the intraoperative examination and treatment of dog menisci are easier after TPLO.