3D Printed Bone Models Research Articles

Three-dimensional computer-assisted corrective osteotomy with a patient-specific surgical guide for an antebrachial limb deformity in two dogs

We describe patient-specific surgical guide prototyping and surgical treatment of a complex antebrachial deformity in two skeletally mature dogs presented with chronic lameness. Computer-assisted surgery was elected to increase accuracy in the correction of the complex deformity. Radiographs and computed tomography (CT) scans revealed a biplane deformity with valgus, procurvatum and external torsion of the right radius in both cases. The pre-surgical planning started from the quantification of the angular deformity, followed by computer simulated correction and to end up with a rehearsal surgery on 3D printed bone models. During the surgery, the custom-made osteotomy guides closely fitted the bone, allowing for a precise corrective osteotomy, that was stabilized with two locking plates. Postoperative radiographs showed the successful correction of the deformity. Eight and 12 weeks postoperative follow up examinations showed improved lameness, weight-bearing and progression of bone healing in both dogs. Patient-specific surgical guides allowed for a satisfactory correction of the antebrachial deformity. Additional benefits of using customized surgical devices include standardization and reduced surgical time.

Biomechanical properties of 3D-printed bone models

Bone lesions resulting from large traumas or cancer resections can be successfully treated by directly using synthetic materials or in combination with tissue engineering methods (hybrid). Synthetic or hybrid materials combined with bone tissue’s natural ability for regeneration and biological adaptation to the directions of loading, allow for full recovery of its biological functions.Increasing interest in new production methods or various types of regenerative membranes and shaped scaffolds means that methods such as additive manufacturing can significantly accelerate the preparation of constructs used in the further biological adaptation of natural tissue. The porosity that allows not only ingrowth of the natural tissue, but also the ability of the synthetic material to transfer loadings in the skeletal system during the regeneration interval, will have a significant impact on regenerative capacities. This work presents the results of preliminary analyzes of bone models in the field of mechanical strength for monotonically and cyclically loading conditions. The determined material constants, such as ultimate tensile strength, Young modulus, and toughness or fatigue life, can be used in numerical simulations of new membranes for the regeneration of damaged bone tissue.

A Case of Avoiding Arterial Injury by Simulation in CT Diagnosis and a 3D Printed Bone Model for Sinus Floor Elevation

A Case of Avoiding Arterial Injury by Simulation in CT Diagnosis and a 3D Printed Bone Model for Sinus Floor Elevation

Accuracy of patient-specific three-dimensional-printed osteotomy and reduction guides for distal femoral osteotomy in dogs with medial patella luxation.

To compare precorrectional and postcorrectional femoral alignment following distal femoral osteotomy using patient-specific 3-dimensional (3D)-printed osteotomy and reduction guides in vivo and ex vivo. Prospective study. Ten client-owned dogs and matching 3D-printed plastic bone models. Distal femoral osteotomy was performed via a standard approach using osteotomy and reduction guides developed with computer-aided design software prior to 3D-printing. Femoral osteotomy and reduction was also performed on 3D-printed models of each femur with identical reprinted guides. Femoral varus angle (FVA) and femoral torsion angle (FTA) were measured on postoperative computed tomographic images by 3 observers. In vivo, the mean difference between target and achieved postoperative was 2.29° (±2.29°, P = .0076) for the FVA, and 1.67° (±2.08°, P = .300) for the FTA. Ex vivo, the mean difference between target and achieved postoperative was 0.29° (±1.50°, P = .813) for the FVA, and -2.33° (±3.21°, P = .336) for the FTA. Intraobserver intraclass correlation coefficients (ICC; 0.736-0.998) and interobserver ICC (0.829 to 0.996) were consistent with an excellent agreement. Use of 3D-printed osteotomy and reduction guides allowed accurate correction of FTA in vivo and both FVA and FTA ex vivo. Use of 3D-printed osteotomy and reduction guides may improve the accuracy of correction of femoral alignment but warrant further evaluation of surgical time, perioperative complications, and patient outcomes compared with conventional techniques.

Proximal third humeral shaft fractures fixed with long helical PHILOS plates in elderly patients: benefit of pre-contouring plates on a 3D-printed model\u2014a retrospective study

BackgroundTo explore the clinical efficacy of 3D printing fracture models to assist in creating pre-contoured plates to treat proximal third humeral shaft fractures.MethodsWe retrospectively identified proximal third humeral shaft fractures treated between February 2012 and February 2015. The patients were divided into two groups according to the treatment procedure: a Synbone group and a 3D-printed group. In the Synbone group, long proximal humeral internal locking system plates were pre-contoured into helical shape on Synbones before surgery, while in the 3D-printed group, they were contoured on 3D-printed bone models. The pre-contoured plates were sterilized before surgery and were then used for fracture fixation during surgery. Duration of surgeries, blood loss volumes, the incidence of complications, and the time to fracture union were recorded, and functional outcomes were assessed by the Constant-Murley shoulder score and the Mayo Elbow Performance Score (MEPS) at 1-year follow-up.ResultsThe subjects comprised 46 patients; 25 patients were allocated to the Synbone group and the remaining 21 to the 3D-printed group. There was no significant difference between the baseline characteristics of the two groups. At the 1-year follow-up visit, all fractures were healed and showed a satisfactory outcome. There were no instances of iatrogenic radial nerve injury, and there was no significant difference between the two groups with regard to fracture union time, Constant-Murley score, or MEPS score. Surgery duration was significantly shorter in the 3D-printed group compared to the Synbone group (42.62 vs. 60.36 min, P = 0.001), and the 3D-printed group lost less blood during surgery (105.19 vs. 120.80 ml, P = 0.001). In addition, in the 3D-printed group, 9 surgeries were finished by senior attending doctors and 12 were finished by junior attending doctors; however, there was no significant difference between the 1-year outcomes of the two grades of surgeons.ConclusionsOur results show that the 3D printing technique is helpful in shortening the duration of surgery, reducing blood loss volume, and in making this surgical procedure easier for less-experienced surgeons.Trial registrationThis clinical study was registered in CHICTR on September 30, 2017 (number 17012852).

Clinical experience with three-dimensional printing techniques in orthopedic trauma.

To report our experiences with the use of three-dimensional (3D) printing in the field of orthopedic trauma. This retrospective study enrolled 24 patients from three university teaching hospitals in whom 3D printing technique was applied: 14 patients with acetabular fractures and 10 patients with clavicular shaft fractures. We summarized our experiences with 3D printed bone models. Three-dimensional printed acetabular models improved understanding of complex acetabular anatomy and fracture pattern to plan the optimal positioning of a reduction clamp and the trajectory of screws. Pre-bending of a reconstruction plate could reduce operative time. We also recorded fluoroscopic images of a simulated surgery for percutaneous screw fixation of the acetabular posterior column, with the optimal positioning of the guide wire determined during the simulation used as a reference during the actual operation. This surgical simulation was performed by a resident and served as a helpful training method. For fractures of the clavicle, we identified the optimal position of anatomical plates using 3D printed clavicle models. In our experience, 3D printing technique provided surgeons with improved understanding of the fracture pattern and anatomy and was effectively used for preoperative planning, education of surgical trainees, and performing simulations to improve intra-operative technical outcomes.

Simplified Summative Temporal Bone Dissection Scale Demonstrates Equivalence to Existing Measures.

Emphasis on patient safety has created the need for quality assessment of fundamental surgical skills. Existing temporal bone rating scales are laborious, subject to evaluator fatigue, and contain inconsistencies when conferring points. To address these deficiencies, a novel binary assessment tool was designed and validated against a well-established rating scale. Residents completed a mastoidectomy with posterior tympanotomy on identical 3D-printed temporal bone models. Four neurotologists evaluated each specimen using a validated scale (Welling) and a newly developed "CanadaWest" scale, with scoring repeated after a 4-week interval. Nineteen participants were clustered into junior, intermediate, and senior cohorts. An ANOVA found significant differences between performance of the junior-intermediate and junior-senior cohorts for both Welling and CanadaWest scales ( P < .05). Neither scale found a significant difference between intermediate-senior resident performance ( P > .05). Cohen's kappa found strong intrarater reliability (0.711) with a high degree of interrater reliability of (0.858) for the CanadaWest scale, similar to scores on the Welling scale of (0.713) and (0.917), respectively. The CanadaWest scale was facile and delineated performance by experience level with strong intrarater reliability. Comparable to the validated Welling Scale, it distinguished junior from senior trainees but was challenged in differentiating intermediate and senior trainee performance.

Modifications to a 3D-printed temporal bone model for augmented stapes fixation surgery teaching.

Functional outcomes and complications in otosclerosis surgery are governed by the surgeon's experience. Thus, teaching the procedure to residents to guide them through the learning process as quickly as possible is challenging. Artificial 3D-printed temporal bones are replacing cadaver specimens in many institutions to learn mastoidectomy, but these are not suitable for middle ear surgery training. The goal of this work was to adapt such an artificial temporal bone to aid the teaching of otosclerosis surgery and to evaluate this tool. We have modified a commercially available 3D-printed temporal bone by replacing the incus and stapes of the model with in-house 3D-printed ossicles. The incus could be attached to a 6-axis force sensor. The stapes footplate was fenestrated and attached to a 1-axis force sensor. Six junior surgeons (residents) and seven senior surgeons (fellows or consultants) were enrolled to perform piston prosthesis placement and crimping as performed during otosclerosis surgery. The time required to perform the tasks and the forces applied to the incus and stapes were collected and analyzed. No statistically significant differences were observed between the junior and senior groups for time taken to perform the tasks and the forces applied to the incus during crimping and placement of the prosthesis. However, significantly lower forces were applied to the stapes by the senior surgeons in comparison with the junior surgeons during prosthesis placement (junior vs senior group, 328±202.9 vs 80±99.6mN, p=0.008) and during prosthesis crimping (junior vs senior group, 565±233 vs 66±48.6mN, p=0.02). We have described a new teaching tool for otosclerosis surgery based on the modification of a 3D-printed temporal bone to implement force sensors on the incus and stapes. This tool could be used as a training tool to help the residents to self-evaluate their progress with recording of objective measurements.

Middle cranial fossa approach to repair tegmen defects assisted by three-dimensionally printed temporal bone models.

To explore the perioperative utility of three-dimensionally (3D)-printed temporal bone models of patients undergoing repair of lateral skull base defects and spontaneous cerebrospinal fluid leaks with the middle cranial fossa approach. Case series. 3D-printed temporal bone models-based on patient-specific, high-resolution computed tomographic imaging-were constructed using inexpensive polymer materials. Preoperatively, the models demonstrated the extent of temporal lobe retraction necessary to visualize the proposed defects in the lateral skull base. Also preoperatively, Silastic sheeting was arranged across the modeled tegmen, marked, and cut to cover all of the proposed defect sites. The Silastic sheeting was then sterilized and subsequently served as a precise intraoperative template for a synthetic dural replacement graft. Of note, these grafts were customized without needing to retract the temporal lobe. Five patients underwent the middle cranial fossa approach assisted by 3D-printed temporal bone models to repair tegmen defects and spontaneous cerebrospinal fluid leaks. No complications were encountered. The prefabricated dural repair grafts were easily placed and fit precisely onto the middle fossa floor without any additional modifications. All defects were covered as predicted by the 3D temporal bone models. At their postoperative visits, all five patients maintained resolution of their spontaneous cerebrospinal fluid leaks. Inexpensive 3D-printed temporal bone models of tegmen defects can serve as beneficial adjuncts during lateral skull base repair. The models provide a panoramic preoperative view of all tegmen defects and allow for custom templating of dural grafts without temporal lobe retraction. 4 Laryngoscope, 127:2347-2351, 2017.

Pre-operative simulation of pediatric mastoid surgery with 3D-printed temporal bone models

ObjectivesAs the process of additive manufacturing, or three-dimensional (3D) printing, has become more practical and affordable, a number of applications for the technology in the field of pediatric otolaryngology have been considered. One area of promise is temporal bone surgical simulation. Having previously developed a model for temporal bone surgical training using 3D printing, we sought to produce a patient-specific model for pre-operative simulation in pediatric otologic surgery. Our hypothesis was that the creation and pre-operative dissection of such a model was possible, and would demonstrate potential benefits in cases of abnormal temporal bone anatomy. MethodsIn the case presented, an 11-year-old boy underwent a planned canal-wall-down (CWD) tympano-mastoidectomy for recurrent cholesteatoma preceded by a pre-operative surgical simulation using 3D-printed models of the temporal bone. The models were based on the child's pre-operative clinical CT scan and printed using multiple materials to simulate both bone and soft tissue structures. To help confirm the models as accurate representations of the child's anatomy, distances between various anatomic landmarks were measured and compared to the temporal bone CT scan and the 3D model. ResultsThe simulation allowed the surgical team to appreciate the child's unusual temporal bone anatomy as well as any challenges that might arise in the safety of the temporal bone laboratory, prior to actual surgery in the operating room (OR). There was minimal variability, in terms of absolute distance (mm) and relative distance (%), in measurements between anatomic landmarks obtained from the patient intra-operatively, the pre-operative CT scan and the 3D-printed models. ConclusionsAccurate 3D temporal bone models can be rapidly produced based on clinical CT scans for pre-operative simulation of specific challenging otologic cases in children, potentially reducing medical errors and improving patient safety.