Multi-directional Le Fort III midfacial distraction using an individual prefabricated device

Craniosynostosis: Le Fort III Distraction Osteogenesis

The Le Fort III advancement was first described in 1950 and has since become a key technique in the armamentarium of craniofacial surgeons. The application of distraction osteogenesis to the craniofacial skeleton has allowed for large movements to be performed safely in young patients. This technique is valuable for correcting exorbitism, airway obstruction owing to midface retrusion, and class III malocclusion. It can be performed with either an external distractor or internal distractors. Although serious complications have been reported, these occur rarely when performed by experienced providers.

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios

Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.

3D printing from MRI Data: Harnessing strengths and minimizing weaknesses

3D printing facilitates the creation of accurate physical models of patient-specific anatomy from medical imaging datasets. While the majority of models to date are created from computed tomography (CT) data, there is increasing interest in creating models from other datasets, such as ultrasound and magnetic resonance imaging (MRI). MRI, in particular, holds great potential for 3D printing, given its excellent tissue characterization and lack of ionizing radiation. There are, however, challenges to 3D printing from MRI data as well. Here we review the basics of 3D printing, explore the current strengths and weaknesses of printing from MRI data as they pertain to model accuracy, and discuss considerations in the design of MRI sequences for 3D printing. Finally, we explore the future of 3D printing and MRI, including creative applications and new materials.

LEVEL OF EVIDENCE

5 J. Magn. Reson. Imaging 2017;45:635-645.

Cost-Benefit Analysis of Three-Dimensional Craniofacial Models for Midfacial Distraction: A Pilot Study

OBJECTIVE

Patient-specific three-dimensional (3D) models are increasingly used to virtually plan rare surgical procedures, providing opportunity for preoperative preparation, better understanding of individual anatomy, and implant prefabrication. The purpose of this study was to assess the benefit of 3D models related to patient safety, operative time, and cost.

DESIGN

Retrospective review.

SETTING

Academic, tertiary care hospital.

PATIENTS, PARTICIPANTS

Midfacial distraction was studied as a representative craniofacial operation. A consecutive series of 29 patients who underwent a single type of midfacial distraction was included.

INTERVENTION

For a subset of patients, computed tomography-derived 3D models were used to study patient-specific anatomy and precontour hardware.

MAIN OUTCOME MEASURES

Complications, operative time, blood loss, and estimated cost.

RESULTS

Twenty patients underwent midfacial distraction without and nine with preoperative use of a 3D model. Seven complications occurred in six patients without model use, including premature consolidation (3), cerebrospinal fluid leak (2), and hardware malfunction (2). No complications were reported in the model group. Controlling for surgeon variation, model use resulted in a 31.3-minute (7.8%) reduction in operative time. Time-based cost savings were estimated to be $1036.

CONCLUSIONS

Three-dimensional models are valuable for preoperative planning and hardware precontouring in craniofacial surgery, with potential positive effects on complications and operative time. Savings related to operative time and complications may offset much of the cost of the model.

Advantages and disadvantages of 3-dimensional printing in surgery: A systematic review

BACKGROUND

Three-dimensional (3D) printing is becoming increasingly important in medicine and especially in surgery. The aim of the present work was to identify the advantages and disadvantages of 3D printing applied in surgery.

METHODS

We conducted a systematic review of articles on 3D printing applications in surgery published between 2005 and 2015 and identified using a PubMed and EMBASE search. Studies dealing with bioprinting, dentistry, and limb prosthesis or those not conducted in a hospital setting were excluded.

RESULTS

A total of 158 studies met the inclusion criteria. Three-dimensional printing was used to produce anatomic models (n = 113, 71.5%), surgical guides and templates (n = 40, 25.3%), implants (n = 15, 9.5%) and molds (n = 10, 6.3%), and primarily in maxillofacial (n = 79, 50.0%) and orthopedic (n = 39, 24.7%) operations. The main advantages reported were the possibilities for preoperative planning (n = 77, 48.7%), the accuracy of the process used (n = 53, 33.5%), and the time saved in the operating room (n = 52, 32.9%); 34 studies (21.5%) stressed that the accuracy was not satisfactory. The time needed to prepare the object (n = 31, 19.6%) and the additional costs (n = 30, 19.0%) were also seen as important limitations for routine use of 3D printing.

CONCLUSION

The additional cost and the time needed to produce devices by current 3D technology still limit its widespread use in hospitals. The development of guidelines to improve the reporting of experience with 3D printing in surgery is highly desirable.

Le Fort II midfacial distraction combined with orthognathic surgery in the treatment of nasomaxillary hypoplasia

Patients with nasomaxillary hypoplasia have severe facial concavity and compromised skeletal class III malocclusion. Its treatment is still a challenge to surgeons. Our aim was to evaluate the combination of midfacial distraction and orthognathic surgery in the treatment of nasomaxillary hypoplasia. Four patients with nasomaxillary hypoplasia were enrolled in this study. After Le Fort II osteotomy, the rotational distraction of nasomaxillary complex was performed to rehabilitate facial convexity. Then bilateral sagittal split ramus osteotomy with or without Le Fort I osteotomy was used to correct malocclusion. All patients healed uneventfully, and the maxillae moved forward conspicuously. No obvious pain and severe discomfort were complained during distraction. A significant advancement and downward movement of the maxilla were shown by cephalometric analysis. The combination of midfacial distraction and orthognathic surgery provides us an ideal alternative in the treatment of nasomaxillary hypoplasia.

Accuracy of medical models made by additive manufacturing (rapid manufacturing)

BACKGROUND

Additive manufacturing (AM) is being increasingly used for producing medical models. The accuracy of these models varies between different materials, AM technologies and machine runs.

PURPOSE

To determine the accuracy of selective laser sintering (SLS), three-dimensional printing (3DP) and PolyJet technologies in the production of medical models.

MATERIAL

3D skull models: "original", "moderate" and "worse". SLS, 3DP and PolyJet models, and a coordinate measuring machine (CMM).

METHODS

Measuring balls designed for measurements were attached to each 3D model. Skull models were manufactured using SLS, 3DP and PolyJet. The midpoints of the balls were determined using CMM. The distances between these points were calculated and compared with the 3D model.

RESULTS

The dimensional error for the PolyJet was 0.18 ± 0.12% (first measurement) and 0.18 ± 0.13% (second measurement), for SLS 0.79 ± 0.26% (first model) and 0.80 ± 0.32% (second model), and for 3DP 0.67 ± 0.43% (original model, first measurement) and 0.69 ± 0.44% (original model, second measurement), 0.38 ± 0.22% (moderate model) and 0.55 ± 0.37% (worse model). Repeatability of the measurement method was 0.12% for the PolyJet and 0.08% for the 3DP.

CONCLUSION

A novel measuring technique was developed and its repeatability was found to be good. The accuracy of the PolyJet was higher when compared with SLS or 3DP.

Maxillary-driven simultaneous maxillo-mandibular distraction for hemifacial microsomia

We treat hemifacial microsomia with a combination of surgery and orthodontic treatment during the growth period, resulting in early improvement in facial asymmetry and the induction of normal growth. We previously used gradual distraction of the mandibular ramus for Pruzansky's type II classification (Pruzansky, 1969). In type II cases, the maxilla should also be treated actively as, using this technique, improvement of the occlusal plane is difficult to achieve, resulting in a cross bite and difficulties in post-operative orthodontic treatment-especially in older patients. Morphologically, the mandibular angle region of the operative side is flat, and the angle of the mouth remains elevated. We performed mandibular-driven simultaneous maxillo-mandibular distraction while the occlusion was maintained using intermaxillary anchorage. However, mandibular-driven distraction tended to elongate the face because the mandible only elongated downwards and the mandibular ramus did not reach the glenoid. Furthermore, external distraction devices produce significant distress for patients until removal of the device and cause scars on the face. We developed a new internal distraction device with a variable angle and performed maxillary-driven simultaneous maxillo-mandibular distraction using this device. The result was morphologically satisfactory and solved the above problems. Because the patient was in the growth period, careful follow-up and induction to normal growth were important while the inferior growth of the affected side was monitored.