Computer-Assisted Craniomaxillofacial Surgery Sean P. Edwards, DDS, MD, FRCD(C)  Oral and Maxillofacial Surgery Clinics  Volume 22, Issue 1, Pages 117-134 (February 2010) DOI: 10.1016/j.coms.2009.11.005 Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 1 In-office CBCT scanner (EWOO Master 3DS; EWOO Technology USA Inc, Houston, TX, USA). Note nonintimidating profile comparable with a conventional panoramic machine. This machine has a minimal footprint and is easily incorporated into the office environment. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 2 (A, B) Typical image quality of CBCT with a large field of view. Quality of skeletal detail is more than adequate for diagnostic and treatment planning purposes. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 3 Young adolescent with hemimandibular hyperplasia and facial asymmetry. The midline discrepancy is obvious and easy to measure. The difference in the height of the inferior border of the mandible is more difficult to quantify, as is the yaw/rotational deformity of the jaws. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 4 (A) CT data reconstructed to show axial, coronal, and sagittal planes along with a three-dimensional view of the head. (B) Virtual skull is aligned according to sagittal, coronal, and axial planes to align the head for analysis. A natural head posture registration could also be used. (C) Three-dimensional reconstruction of CT data permits three-dimensional analysis to help the surgeon understand and quantify a complex deformity. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 5 Cutting planes are established and the data segmentation accomplished to simulate a LeFort I osteotomy, sagittal split of the mandible, and asymmetric sliding genioplasty. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 6 Stereolithographic model of a complex asymmetry associated with type III hemifacial microsomia. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 7 Stereolithographic model of an adolescent severely affected with cherubism. Measurements can be taken from this model to plan and establish goals for the remodeling procedures. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 8 (A) Surgical navigation is analogous to a GPS system in a car. The navigation tower consists of a camera and a monitor. The camera registers the position of the patient and the navigation probe and displays the position of the probe on the monitor. (B) At the beginning of a case, landmarks on a patient are registered to corresponding landmarks on their CT data set. To maintain this linkage, a system to track movement of the patient is required. In this case, the Medtronic Stealth System (Medtronic Navigation Inc, Minneapolis, MN, USA) uses a headband with 4 fiducial markers. Changes in the position of the patient's head are reflected in position changes in the markers that are tracked by the camera. (C, D) Instruments and probes with a similar fiducial system are tracked by the camera to display progress on the patient's CT scan. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 9 CAS workflow dogma. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 10 (A) Axial view of large desmoid tumor in a 4-year-old boy. (B) Coronal views of the same. (C) Three-dimensional view with deformed mandibular half segmented. (D) Deformed half removed. (E) Mirrored left mandible aligned to replace the deformed right hemimandible. (F) Comparison of stereolithographic models of new mandible and deformed mandible. The new mandible model becomes the surgical objective and the template to guide the reconstructive process. (G) Reconstruction plate is adapted to the new mandible. It is then sterilized and taken to the operating room to guide the reconstruction. (H) Tumor is resected. (I) Specimen. (J) Plate fixed to residual mandible and rib grafts are then fixed to the plate. (K) Closure with resulting good symmetry and form of the new mandible after a three-quarter mandibulectomy, (L) Frontal view at closure. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 10 (A) Axial view of large desmoid tumor in a 4-year-old boy. (B) Coronal views of the same. (C) Three-dimensional view with deformed mandibular half segmented. (D) Deformed half removed. (E) Mirrored left mandible aligned to replace the deformed right hemimandible. (F) Comparison of stereolithographic models of new mandible and deformed mandible. The new mandible model becomes the surgical objective and the template to guide the reconstructive process. (G) Reconstruction plate is adapted to the new mandible. It is then sterilized and taken to the operating room to guide the reconstruction. (H) Tumor is resected. (I) Specimen. (J) Plate fixed to residual mandible and rib grafts are then fixed to the plate. (K) Closure with resulting good symmetry and form of the new mandible after a three-quarter mandibulectomy, (L) Frontal view at closure. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 11 (A) Anterior mandibular defect caused by gunshot wound. (B) Three-dimensional data sets of the mandibular defect. On the right is a frontal view of the treatment objective, which was developed by taking stock mandibular CT scan images and finding one that matched the desired gonial width and chin projection. (C) Lateral view of preoperative condition and treatment objective. (D) This treatment objective data set is used to fabricate a stereolithographic model that can then be used to adapt a reconstruction plate and bone flap and approximate the virtual treatment objective. (E) Plate adapted to the customized model. (F) Free fibula osteocutaneous flap osteotomized to adapt intimately to the plate, achieving the treatment objective. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 12 (A) Fibula free flap harvest to reconstruct a hemimandibulectomy defect. Shaping is accomplished at the leg while the flap continues to be perfused. The fibula bone is cut according to the length of the template. The template can be held in place with a Kocher clamp. A wedge of bone is removed from the center of the fibula according to the plan to replicate the patient's gonial angle. (B) SLA model is fabricated to permit off field adaptation of the reconstruction plate. Shaped fibula matches the reconstructive plan. (C) Cutting template is positioned on the fibula, which sets the length of bone for the planned reconstruction. The middle cut-out sets the angle and amount of bone that needs to be removed for an accurate closing osteotomy. (D) Shaped and plated fibula flap. Stereolithographic model of the planned operation adjacent to the shaped flap, demonstrating concordance between the planning and the operation. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 13 Maxillary distraction case planned using buried distractors. Devices are virtually selected. Parallelism is assured, as is the angle of declination to achieve vertical lengthening of the maxilla while sagittal lengthening is ongoing. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 14 (A) A 4-year-old boy with Treacher Collins syndrome and severe obstructive sleep apnea. He had previously undergone distraction at 11 months of age. His mandibular anatomy is markedly abnormal. (B) CT data are acquired and analytical stage is begun. (C) A buried, single-vector distraction device is chosen and positioned to achieve the desired result. (D) A vector transfer guide (in red) is then virtually designed. The design of this guide is such that it can easily be positioned on the native mandible and adapts well to the contours of the distractor. It is purposefully designed to be larger than will be used in the operating room to permit customizing the guide further as the operative situation dictates. (E) A model and transfer guide are fabricated using RP techniques. The mandibular model allows the distractor to be adapted for a precise fit, whereas the vector transfer guide ensures the desired orientation. (F) The mandible is exposed and the template seated. (G) The distractor is seated in the template, replicating the treatment objective. (H) Distraction is accomplished having avoided injury to developing tooth buds. (I) Predistraction lateral view. (J) Postdistraction lateral view. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 14 (A) A 4-year-old boy with Treacher Collins syndrome and severe obstructive sleep apnea. He had previously undergone distraction at 11 months of age. His mandibular anatomy is markedly abnormal. (B) CT data are acquired and analytical stage is begun. (C) A buried, single-vector distraction device is chosen and positioned to achieve the desired result. (D) A vector transfer guide (in red) is then virtually designed. The design of this guide is such that it can easily be positioned on the native mandible and adapts well to the contours of the distractor. It is purposefully designed to be larger than will be used in the operating room to permit customizing the guide further as the operative situation dictates. (E) A model and transfer guide are fabricated using RP techniques. The mandibular model allows the distractor to be adapted for a precise fit, whereas the vector transfer guide ensures the desired orientation. (F) The mandible is exposed and the template seated. (G) The distractor is seated in the template, replicating the treatment objective. (H) Distraction is accomplished having avoided injury to developing tooth buds. (I) Predistraction lateral view. (J) Postdistraction lateral view. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 15 (A) Complex asymmetric deformity that would be difficult to quantify from traditional two-dimensional imaging modalities. (B) Three-dimensional view of the same patient. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions

Fig. 16 Surgical treatment objective developed by segmenting and repositioning the mandible, chin, and maxilla. Oral and Maxillofacial Surgery Clinics 2010 22, 117-134DOI: (10.1016/j.coms.2009.11.005) Copyright © 2010 Elsevier Inc. Terms and Conditions