Three-dimensional (3D) printing has been particularly widely adopted in medical fields. Application of the 3D printing technique has even been extended to bio-cell printing for 3D tissue/organ development, the creation of scaffolds for tissue engineering, and actual clinical application for various medical parts. Of various medical fields, craniofacial plastic surgery is one of areas that pioneered the use of the 3D printing concept. Rapid prototype technology was introduced in the 1990s to medicine via computer-aided design, computer-aided manufacturing. To investigate the current status of 3D printing technology and its clinical application, a systematic review of the literature was conducted. In addition, the benefits and possibilities of the clinical application of 3D printing in craniofacial surgery are reviewed, based on personal experiences with more than 500 craniofacial cases conducted using 3D printing tactile prototype models.

Background Parry-Romberg disease is a rare condition that results in progressive hemifacial atrophy, involving the skin, dermis, subcutaneous fat, muscle, and, finally, cartilage and bone. Patients have been treated with dermofat or fat grafts or by microvascular free flap transfer. We hypothesized that adipose-derived stem cells (ASCs) may improve the results of microfat grafting through enhancing angiogenesis. We evaluated the utility of ASC in microfat grafting of patients with Parry-Romberg disease by measuring the change in the hemifacial volumes after injection of ASCs with microfat grafts or microfat grafts alone. Methods In April 2008, this investigation was approved by the Korean Food and Drug Administration and the institutional review board of the Asan Medical Center (Seoul, Korea) that monitor investigator-initiated trials. Between May 2008 and January 2009, 10 volunteers with Parry-Romberg disease (5 men and 5 women; mean age, 28 y) were recruited; 5 received ASC and microfat grafts and 5 received microfat grafts only. The mean follow-up period was 15 months. Adipose-derived stem cells were obtained from abdominal fat by liposuction and were cultured for 2 weeks. On day 14, patients were injected with fat grafts alone or plus (in the test group) 1 × 10⁷ ASCs. Patients were evaluated postoperatively using a 3-dimensional camera and 3-dimensional CT scans, and grafted fat volumes were objectively calculated. Results Successful outcomes were evident in all 5 patients receiving microfat grafts and ASCs, and the survival of grafted fat was better than in patients receiving microfat grafts alone. Before surgery, the mean difference between ipsilateral and contralateral hemiface volume in patients receiving microfat grafts and ASCs was 21.71 mL decreasing to 4.47 mL after surgery. Overall resorption in this ASC group was 20.59%. The mean preoperative difference in hemiface volume in those receiving microfat grafts alone was 8.32 mL decreasing to 3.89 mL after surgery. Overall resorption in this group was 46.81%. The preoperative and postoperative volume differences between the groups was statistically significant (P = 0.002; random-effects model [SAS 9.1]). Conclusions Adipose-derived stem cells enhance the survival of fat grafted into the face. A microfat graft with simultaneous ASC injection may be used to treat Parry-Romberg disease without the need for microvascular free flap transfer.

The endocranial morphology of the skull base is an important factor in determining craniofacial asymmetry. Moreover, although the patency of cranial suture would be the first determining factor, unicoronal, unilambdoid synostosis and deformational plagiocephaly can also be differentiated by means of axis angulation of anterior and posterior cranial fossa. These findings indicate the importance of endocranial morphology in craniofacial asymmetry. The authors hypothesized that distraction of the skull base might cause stress on the skull base that could modify skull base angulation deformities. This study compared the distraction technique with traditional bone repositioning techniques for remodeling skull base axis deformities in synostotic plagiocephaly patients. The study recruited 19 unicoronal craniosynostotic patients, of whom seven underwent distraction treatment and 12 underwent traditional bone graft treatment. The authors found that both approaches resulted in successful outcomes in terms of exocranial morphology correction, but that the distraction technique may offer advantages over traditional methods. Moreover, the authors found that distraction did modify the skull base angulation. Distraction created more changes in the endocranial morphology. The average correction of skull base angulation with distraction was from 164.6 to 174.3 degrees, whereas the correction for the traditional technique was from 165.2 to 166.2 degrees. The amount of change in skull base axis was statistically significant according to the Mann-Whitney test (p < 0.001), but the change in cranial index of asymmetry was not (p = 0.363). The skull base axis in synostotic plagiocephaly, which is composed of the anterior and posterior cranial fossa, underwent greater correction using the distraction method.

Background: It is difficult to restore original orbital contours because of their complex 3-dimensional structure. Moreover, slight implant malpositioning can result in enophthalmos or other complications. The authors describe our experience of using individualized prebent titanium-Medpor mesh implants and stereolithographic modeling in a series of patients who underwent orbital wall reconstruction. Methods: A consecutive series of 104 patients with orbital fractures received computer simulation-designed prebent titanium-Medpor mesh implants insertion. Preoperative computed tomography (CT) data were processed for each patient, and a rapid prototyping (RP) model was produced. The uninjured side was concurrently mirrored and superimposed onto the traumatized side to create a mirror image of the RP model. The authors fabricated the titanium-Medpor implants to intraoperatively reconstruct the 3-dimensional orbital structure. The prefabricated titanium-Medpor implants were inserted into the defective orbital wall and fixed. Postoperative CT images were immediately taken to evaluate the reconstructed contours and compare the preoperative and postoperative intraorbital volumes. Results: All reconstructions were successful without postoperative complications. The implants were correctly positioned in the sagittal, axial, and coronal planes relative to the original orbital contours. The mean preoperative intraorbital volumes of the uninjured and traumatized sides were 21.39 ± 1.93 and 23.17 ± 2.00 cm³, respectively, and the postoperative mean intraorbital volume was 20.74 ± 2.07 cm³. Conclusions: Orbital reconstruction can be optimized using individually manufactured rapid prototype skull model and premolded synthetic scaffold by computer-aid of mirroring-reconstruction of 3-dimensional images and 3-dimensional printing techniques.