Three-dimensional printing of orbital and peri-orbital masses in three dogs and its potential applications in veterinary ophthalmology

Towards Precision Ophthalmology: The Role of 3D Printing and Bioprinting in Oculoplastic Surgery, Retinal, Corneal, and Glaucoma Treatment

In the forefront of ophthalmic innovation, biomimetic 3D printing and bioprinting technologies are redefining patient-specific therapeutic strategies. This critical review systematically evaluates their application spectrum, spanning oculoplastic reconstruction, retinal tissue engineering, corneal transplantation, and targeted glaucoma treatments. It highlights the intricacies of these technologies, including the fundamental principles, advanced materials, and bioinks that facilitate the replication of ocular tissue architecture. The synthesis of primary studies from 2014 to 2023 provides a rigorous analysis of their evolution and current clinical implications. This review is unique in its holistic approach, juxtaposing the scientific underpinnings with clinical realities, thereby delineating the advantages over conventional modalities, and identifying translational barriers. It elucidates persistent knowledge deficits and outlines future research directions. It ultimately accentuates the imperative for multidisciplinary collaboration to enhance the clinical integration of these biotechnologies, culminating in a paradigm shift towards individualized ophthalmic care.

Applications of 3-dimensional printing in small-animal surgery: A review of current practices

Three-dimensional (3D) printing, also called rapid prototyping or additive manufacturing, transforms digital images into 3D printed objects, typically by layering consecutive thin films of material. This technology has become increasingly accessible to the public, prompting applications in veterinary surgery. Three-dimensional prints provide direct visualization of complex 3D structures and also haptic feedback relevant to surgery. The main objective of this review is to report current applications of 3D printing in small-animal surgery, including surgical education, preoperative planning, and treatment of tissue defects. The reported uses of 3D prints, their proposed advantages, and current limitations are discussed considering published evidence. Aspects of the manufacturing process specific to each application are described, along with current practices in veterinary surgery.

A review of additive manufacturing applications in ophthalmology

Additive Manufacturing (AM) capabilities in terms of product customization, manufacture of complex shape, minimal time, and low volume production those are very well suited for medical implants and biological models. AM technology permits the fabrication of physical object based on the 3D CAD model through layer by layer manufacturing method. AM use Magnetic Resonance Image (MRI), Computed Tomography (CT), and 3D scanning images and these data are converted into surface tessellation language (STL) file for fabrication. The applications of AM in ophthalmology includes diagnosis and treatment planning, customized prosthesis, implants, surgical practice/simulation, pre-operative surgical planning, fabrication of assistive tools, surgical tools, and instruments. In this article, development of AM technology in ophthalmology and its potential applications is reviewed. The aim of this study is nurturing an awareness of the engineers and ophthalmologists to enhance the ophthalmic devices and instruments. Here some of the 3D printed case examples of functional prototype and concept prototypes are carried out to understand the capabilities of this technology. This research paper explores the possibility of AM technology that can be successfully executed in the ophthalmology field for developing innovative products. This novel technique is used toward improving the quality of treatment and surgical skills by customization and pre-operative treatment planning which are more promising factors.

An Easy and Economical Way to Produce a Three-Dimensional Bone Phantom in a Dog with Antebrachial Deformities

Simple Summary

Accurate planning, for corrective surgeries in case of bone cutting, is necessary to obtain a precise coordination of the skeleton and to achieve the owner’s satisfaction. The present experiment displays a simple and cost-effective technique for surgical planning, utilizing a 3-D bone phantom model in a dog with foreleg deformity.

Abstract

3-D surgical planning for restorative osteotomy is costly and time-consuming because surgeons need to be helped from commercial companies to get 3-D printed bones. However, practitioners can save time and keep the cost to a minimum by utilizing free software and establishing their 3-D printers locally. Surgical planning for the corrective osteotomy of antebrachial growth deformities (AGD) is challenging for several reasons (the nature of the biapical or multiapical conformational abnormalities and lack of a reference value for the specific breed). Pre-operative planning challenges include: a definite description of the position of the center of rotation of angulation (CORA) and proper positioning of the osteotomies applicable to the CORA. In the present study, we demonstrated an accurate and reproducible bone-cutting technique using patient-specific instrumentations (PSI) 3-D technology. The results of the location precision showed that, by using PSIs, the surgeons were able to accurately replicate preoperative resection planning. PSI results also indicate that PSI technology provides a smaller standard deviation than the freehand method. PSI technology performed in the distal radial angular deformity may provide good cutting accuracy. In conclusion, the PSI technology may improve bone-cutting accuracy during corrective osteotomy by providing clinically acceptable margins.

3D anatomical model for teaching canine lumbosacral epidural anesthesia

Purpose

To develop a 3D anatomical model for teaching canine epidural anesthesia (3DMEA) and to assess its efficacy for teaching and learning prior to the use of live animals.

Methods

The creation of 3DMEA was based on 3D optical scanning and 3D printing of canine bone pieces of the fifth to the seventh lumbar vertebrae, sacrum and pelvis. A total of 20 male dogs were scheduled for castration. 20 veterinary students watched a video showing epidural anesthesia in dogs before the clinical attempt and were assigned to control or 3DMEA groups. Students in the 3DMEA group trained in the model after the video. For the clinical trial, the epidural procedure was performed by students under the veterinary supervision. When observed the absence of response to nociceptive stimuli, the epidural was considered successful. Then, all students answered a questionnaire evaluating the main difficulty founded in the technique and its degree of difficulty.

Results

The 3DMEA group reported a lower degree of difficulty to perform the epidural anesthesia technique when compared with the control group (p=0.0037). The 3DMEA reproduced the anatomical structures, allowing the perception of the distance of needle in relation to the iliac prominences during epidural anesthesia. Its mobility allowed simulation of the animal in standing position and sternal recumbency.

Conclusion

The use of 3DMEA demonstrated greater efficacy in the execution of the technique, being effective in the teaching and learning process before the epidural anesthesia in live animals.

Canaliculorhinostomy as a treatment for nasolacrimal duct obstruction in dogs and cats

OBJECTIVES

To create a replacement nasolacrimal system, using the puncta and canaliculi, with prolonged implant retention and minimal use of Elizabethan collars or other restraint devices.

MATERIALS AND METHODS

The method was used in 11 dogs and two cats. Silicone tubing was placed through both canaliculi and, via a drill hole, into the nasal cavity. Distally, the tubing ends were tied in a subcutaneous pocket lateral to the premaxilla. Tubing retention time was 4 to 7 months. Elizabethan collars were used only until skin suture removal at 2 weeks.

RESULTS

In all animals, a functional nasolacrimal system was re-created and remained patent over prolonged follow-up periods. Adverse effects and complications were mild.

CLINICAL SIGNIFICANCE

The described method is relatively straightforward, thereby making relief of tear outflow problems widely accessible.

Printing 3D models of canine jaw fractures for teaching undergraduate veterinary medicine

Purpose

To develop 3D anatomical models, and corresponding radiographs, of canine jaw fractures.

Methods

A base model was generated from a mandibular bone scan. With this model it was possible to perform fracture planning according to the anatomical location.

Results

The 3D base model of the canine mandible was similar in conformation to the natural bone, demonstrating structures such as canine tooth crowns, premolars and molars, mental foramina, body of the mandible, ramus of the mandible, masseteric fossa, the coronoid process, condylar process, and angular process. It was not possible to obtain detail of the crown of the incisor teeth, mandibular symphysis, and the medullary channel. Production of the 3D CJF model took 10.6 h, used 150.1 g of filament (ABS) and cost US$5.83.

Conclusion

The 3D canine jaw fractures models, which reproduced natural canine jaw fractures, and their respective radiographic images, are a possible source of educational material for the teaching of veterinary medicine.

Evaluation of cytology and histopathology for the diagnosis of canine orbital neoplasia: 112 cases (2004-2019) and review of the literature

OBJECTIVE

To provide an updated overview of canine orbital neoplasia, to compare diagnostic utility of cytology and histopathology, and to evaluate alternative sampling modalities, particularly image-guided core needle biopsy.

PROCEDURES

A medical records search was performed to identify dogs with orbital neoplasia. Data were collected regarding signalment, diagnosis, vision status, imaging modalities, and sample collection methods. A reference population with orbital neoplasia was also identified via literature search for comparison with regard to final diagnosis.

RESULTS

One hundred and twelve dogs met selection criteria. In the study and reference populations, respectively, diagnoses were grouped as follows: mesenchymal tumors 40% and 35%, epithelial tumors 35% and 18%, tumors of neural origin 8% and 37%, and round cell 17% and 10%. The most common diagnoses in the study group were nasal adenocarcinoma, osteosarcoma, lymphoma, and meningioma. Cytology results were available for 47 dogs and histopathology results were available for 95 dogs. Both cytology and histopathology results were available for 30 dogs, in 53% of which results were discordant. Cytology samples were nondiagnostic or provided a diagnosis that was later overturned in 32% of cases in which they were obtained. Results from core needle biopsy samples were nondiagnostic or overturned by surgical biopsy results in only 13% of cases. No significant complications were associated with any sampling method.

CONCLUSIONS

Orbital neoplasia is common in dogs. Histopathology is superior to cytology in providing a definitive diagnosis. Image-guided core needle biopsy appears to be a safe and effective means of obtaining samples.

Applications of three-dimensional printing in orbital diseases and disorders

PURPOSE OF REVIEW

To comprehensively review the applications of advanced three-dimensional printing technology in the management of orbital abnormalities.

RECENT FINDINGS

Three-dimensional printing has added value in the preoperative planning and manufacturing of patient-specific implants and surgical guides in the reconstruction of orbital trauma, congenital defects and tumor resection. In view of the costs and time, it is reserved as strategy for large and complex craniofacial cases, in particular those including the bony contour. There is anecdotal evidence of a benefit of three-dimensional printing in the manufacturing of prostheses for the exenterated and anophthalmic socket, and in the fabrication of patient-specific boluses, applicators and shielding devices for orbital radiation therapy. In addition, three-dimensional printed healthy and diseased orbits as phantom tangible models may augment the teaching and learning process of orbital surgery.

SUMMARY

Three-dimensional printing allows precision treatment tailored to the unique orbital anatomy of the patient. Advancement in technology and further research are required to support its wider use in orbital clinical practice.

The accuracy of computed tomography scans for rapid prototyping of canine skulls

This study’s objective was to determine the accuracy of using current computed tomography (CT) scan and software techniques for rapid prototyping by quantifying the margin of error between CT models and laser scans of canine skull specimens. Twenty canine skulls of varying morphology were selected from an anatomy collection at a veterinary school. CT scans (bone and standard algorithms) were performed for each skull, and data segmented (testing two lower threshold settings of 226HU and -650HU) into 3-D CT models. Laser scans were then performed on each skull. The CT models were compared to the corresponding laser scan to determine the error generated from the different types of CT model parameters. This error was then compared between the different types of CT models to determine the most accurate parameters. The mean errors for the 226HU CT models, both bone and standard algorithms, were not significant from zero error (p = 0.1076 and p = 0.0580, respectively). The mean errors for both -650HU CT models were significant from zero error (p < 0.001). Significant differences were detected between CT models for 3 CT model comparisons: Bone (p < 0.0001); Standard (p < 0.0001); and -650HU (p < 0.0001). For 226HU CT models, a significant difference was not detected between CT models (p = 0.2268). Independent of the parameters tested, the 3-D models derived from CT imaging accurately represent the real skull dimensions, with CT models differing less than 0.42 mm from the real skull dimensions. The 226HU threshold was more accurate than the -650HU threshold. For the 226HU CT models, accuracy was not dependent on the CT algorithm. For the -650 CT models, bone was more accurate than standard algorithms. Knowing the inherent error of this procedure is important for use in 3-D printing for surgical planning and medical education.

A surgical approach for extensive orbital exenteration in dogs; a description of technique and its application in 4 cases

OBJECTIVE

To describe a surgical approach for preplanned orbital exenteration.

ANIMALS STUDIED

Indications included intraconal orbital mass lesions. Four dogs were included, 3 with neoplasia and one with retro bulbar nodular fasciitis.

PROCEDURE

To facilitate complete removal of lesions, exenteration was performed by a new procedure for wide access. The frontalis and temporalis muscles were elevated and retracted through a single U-shaped skin incision. Zygomatic arch osteotomy was performed, followed by a 360-degree peritomy and zygomatic process osteotomy. The eyelids were divided from each other through the lateral cantus and then folded forward to expose the globe. The orbit was exenterated by blunt and sharp dissection. Osteotomies were closed with cerclage wires, soft tissues closed and the skin wound sutured in a T-shape.

RESULTS

The present exenteration procedure gave excellent access to remove orbital contents flush with the optic foramen and orbital fissure. Postoperative swelling and pain were limited and healing uneventful. Two of the 3 neoplasia cases experienced tumor recurrence involving the brain at 18 and 20 months postoperatively, respectively. Both of these had optic canal or intracranial tumor extension preoperatively. Long-term complications included mild concavity of the operated side of the face.

CONCLUSIONS

The present approach for preplanned exenteration offers excellent access for complete removal of orbital contents to the level of the optic foramen. Complications due to the surgical method are few and limited.

Use of Three-Dimensional Printing Models for Veterinary Medical Education: Impact on Learning How to Identify Canine Vertebral Fractures

Vertebral fractures and luxations are common causes of neurological emergencies in small-animal patients. The objective of this study was to evaluate the impact of three-dimensional printing (3Dp) models on how veterinary students understand and learn to identify canine spinal fractures and to compare 3Dp models to computed tomography (CT) images and three-dimensional CT (3D-CT) reconstructions. Three spinal fracture models were generated by 3Dp. Sixty first-year veterinary students were randomized into three teaching module groups (CT, 3D-CT, or 3Dp) and asked to answer a multiple-choice questionnaire with 12 questions that covered normal spinal anatomy and the identification of vertebral fractures. We used four additional questions to evaluate the overall learning experience and knowledge acquisition. Results showed that students in the 3Dp group performed significantly better than those in the CT (p < .001) and the 3D-CT (p < .001) groups. Students in the 3Dp and 3D-CT groups answered all questions more quickly than the CT group (3Dp versus CT, p < .001; 3D-CTversus CT, p < .001), with no significant differences between the 3Dp and 3D-CT groups (p = .051). Only the degree of knowledge acquisition that the students considered they had acquired during the session showed significant differences between groups (p = .01). In conclusion, across first-year veterinary students, 3Dp models facilitated learning about normal canine vertebral anatomy and markedly improved the identification of canine spinal fractures. Three-dimensional printing models are an easy and inexpensive teaching method that could be incorporated into veterinary neuroanatomy classes to improve learning in undergraduate students.