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Abstract
Hemifacial microsomia (HFM) is a common congenital craniofacial deformity with a high prevalence. Orthognathic surgery and distraction osteogenesis are two conventionally used treatments of HFM. The main objective of this retrospective study was to evaluate the accuracy of two treatments with the help of virtual surgical planning in adult HFM patients. Sixty-eight adult patients with unilateral HFM were enrolled in this study. Preoperative surgical planning and simulation were performed on three-dimensional computed tomography models. Orthognathic surgery or distraction osteogenesis was performed under the guidance of three-dimensional surgical templates. Postoperative evaluation of the intervention was performed by comparison of the affected ramus height, chin deviation and the occlusal cant in surgical planning and actual result. Outcome and feedback information (an average of 14 months) showed that virtual surgical planning was accurately transferred to actual surgery in both surgical approaches. There were no statistical differences between the accuracy of affected ramus height and the occlusal cant in two surgical approaches. The orthognathic group showed significantly higher accuracy in chin deviation. In conclusion, virtual surgical planning and three-dimensional surgical templates were proved to facilitate treatment planning and offer an accurate surgical result in the treatment of adult HFM patients.
... In some patients affected by hemifacial microsomia, it is necessary to plan orthognathic surgery treatment for mandibular reconstruction. In these patients who are candidates for mandibular reconstruction, it is essential to plan the surgery and the results of the surgery using cone beam computed tomography [12,13]. ...
... Because of the malformations and oral alterations that these patients usually present, the involvement of dentists/orthodontists and oral surgeons in the treatment of orthognathic surgery is essential in the multidisciplinary management of these patients [12,40]. Orthodontists should plan the treatment of the dental malocclusions presented by these patients. ...
Hemifacial microsomia is the second most common congenital anomaly of the craniofacial region. Hemifacial microsomia is characterised by unilateral hypoplasia of the ear. Treatment of this condition depends on the severity of the lesion. The treatment of hemifacial microsomia must be carried out by a multidisciplinary group of professionals familiar with this pathology, including plastic surgeons, parapsychologists, orthodontists, and paediatricians. In hemifacial microsomia, microtia is usually accompanied by alterations of the middle ear. Since the ear develops embryonically from the first and second branchial arches, the facial areas that also develop from these embryonic origins are usually affected to a greater or lesser degree, including through hypoplasia of the jaw, maxilla, zygomatic bones, and temporal bone, among others. Although jaw hypoplasia is the most evident deformity in craniofacial microsomia, microtia is the alteration that often has the greatest aesthetic impact on patients. Alterations in dentition are also common, typically presenting as a cephalad inclination of the anterior occlusal plane of the maxilla and mandible on the affected side. This study aims to review the surgical approach and evaluate the results of a paediatric case of hemifacial microsomia. Hemifacial microsomia is present at birth, and successful reconstruction is essential for the correct integration of such infantile patients into society. Multiple facial asymmetries as well as neonatal onset are a challenge for reconstructive surgery, and the importance of multidisciplinary treatment in these patients must be emphasised.
... (4) Facial Fractures: For zygomatic arch fractures, the anatomical region that is unaffected by a deformity can be mirrored to the lesion side and overlaid against the affected anatomical region by using the MSP (optimal symmetry planes, OSPs) to acquire a harmonized and balanced facial structure [37,48,67,77]. (5) Reconstructive surgery for hemifacial microsomia: Conventional treatment for patients with hemifacial microsomia (HFM) involves OGS and distraction osteogenesis of the mandible [78,79]. For mandibular distraction osteogenesis, virtual osteotomy positions and configurations, including linear oblique, inverted L, and multiangular, are customized for each patient. ...
... For chromatic aberration index, the differences between VSP and postoperative images after initial registration of the cranial base simulation images with the actual postsurgical images is evaluated by using a visual overlapping degree of two surface models. Model fusion tools are commonly applied to the automatically display of the size, direction, and location of discrepancy between the two models; this is accomplished by color-coding the visualization and root-mean-square deviation (RMSD) values [18,20,44,78]. For descriptive statistical analyses, 3D cephalometric analyses are performed using anatomical landmarks, reference planes, and measurements (distance and angle) [33,90]. ...
Background:
Three-dimensional (3D) imaging technologies are increasingly used in craniomaxillofacial (CMF) surgery, especially to enable clinicians to get an effective approach and obtain better treatment results during different preoperative and postoperative phases, namely during image acquisition and diagnosis, virtual surgical planning (VSP), actual surgery, and treatment outcome assessment. The article presents an overview of 3D imaging technologies used in the aforementioned phases of the most common CMF surgery.
Material and methods:
We searched for relevant studies on 3D imaging applications in CMF surgery published over the past 10 years in the PubMed, ProQuest (Medline), Web of Science, Science Direct, Clinical Key, and Embase databases.
Results:
A total of 2094 articles were found, of which 712 were relevant. An additional 26 manually searched articles were included in the analysis.
Conclusions:
The findings of the review demonstrated that 3D imaging technology is becoming increasingly popular in clinical practice and an essential tool for plastic surgeons. This review provides information that will help for researchers and clinicians consider the use of 3D imaging techniques in CMF surgery to improve the quality of surgical procedures and achieve satisfactory treatment outcomes.
... This corroborates with other studies where similar benefits were obtained. [17][18][19] A wide spectrum of useful tools that are available to enhance the efficacy of the distraction procedure are stereolithographic models, [20] Three-dimensional cephalometric treatment planning, [20] geometric models, computer-aided surgery, [21] ultrasound and endoscopy. However, the key to success for each case of DO is careful treatment planning, which includes detailed PA and lateral cephalometric analyses, prediction tracings, analyses of the OPGs, and model analyses, and their incorporation into the operative procedure as well as the distraction protocol. ...
... This corroborates with other studies where similar benefits were obtained. [17][18][19] A wide spectrum of useful tools that are available to enhance the efficacy of the distraction procedure are stereolithographic models, [20] Three-dimensional cephalometric treatment planning, [20] geometric models, computer-aided surgery, [21] ultrasound and endoscopy. However, the key to success for each case of DO is careful treatment planning, which includes detailed PA and lateral cephalometric analyses, prediction tracings, analyses of the OPGs, and model analyses, and their incorporation into the operative procedure as well as the distraction protocol. ...
Introduction: Distraction osteogenesis, has emerged as a revolutionary concept and an effective means to treat extensive craniomaxillofacial
defects and malformations. In cases of mandibular distraction for patients with extreme acquired mandibular deformities, there is so far, no
recorded literature on precise quantification and scientific estimation of the percentage of the efficacy of intraoral monoplanar distractors, for
an objective evaluation of their effectiveness. The objective was to study the efficacy of intraoral mandibular monoplanar distractors in the
correction of severe acquired mandibular deformities and gross facial asymmetries. To objectively evaluate their effectiveness by calculating
the percentage of distraction achieved as against that aimed for, and to evaluate early and late complications encountered with their use.
Materials and Methods: Five patients in the age group of 10–22 years, with extreme mandibular deformity and gross facial asymmetry
secondary to longstanding temporomandibular joint (TMJ) ankylosis, were treated. Four patients had unilateral and one patient had bilateral
TMJ ankylosis, with varying degrees of acquired mandibular hypoplasia, retrogenia, retrognathia, and asymmetry. They were managed by
unilateral (3 patients) and bilateral (2 patients) mandibular distraction. Results: Maximum horizontal corpus and vertical Ramal distraction
achieved was 19 mm and 17.6 mm, respectively. The percentage of the efficacy of the intraoral monoplanar distractors used in this study ranged
from 65.38% to 109.09%. Severe mandibular deformities and facial asymmetries were successfully corrected in all five patients, with no major
early or late complications encountered in any of them. Results achieved were stable with nil incidence of relapse. Discussion: Estimation of
percentage of the efficacy of distraction achieved, helped in objectively evaluating the effectiveness of the intraoral mandibular distractors.
A low complication rate and good esthetic and functional outcomes achieved in all the patients demonstrated the reliability of this treatment
modality in the management of extreme mandibular deformities and severe facial asymmetries.
... Moreover, the designed surgical device can be accurately produced following the simulation and computer-aided design (CAD) using 3D printing with stereolithography technique [2]. These digital trends can be applied to distraction as well as to the general treatment of maxillofacial deformity [3,4]. ...
... In order to address the issues of direction and stability, we previously introduced a way to transfer 3D positional information from simulation to the operation field with the aid of a positioning guide (Korean patents 10-0079973 & 0158632). Previous studies have introduced 3Dprinted positioning guides [4,7] or navigation equipment [15]. Our current study attempted two kinds of positioning guide for bone plate (in group 1) or for bone plate plus distraction device (in group 2). ...
Background
A new distraction osteogenesis assembly system comprising a fully customized CAD/CAM-based fixation unit and ready-made distraction unit was developed. The aim of this study was to introduce our new distraction system and to evaluate its accuracy level in a sampled mandibular distraction osteogenesis.
Methods
Our system consists of a fully customized CAD/CAM-based fixation plate unit with two plates for each moving and anchoring part, and a ready-made distraction unit with attachment slots for fixation plates. The experimental distractions were performed on 3D-printed mandibles for one control and two experimental groups ( N = 10 for each group). All groups had reference bars on the chin region and teeth to measure distraction accuracy. The control group had the classical ready-made distraction system, and experimental groups 1 and 2 were fitted with our new distraction assembly using a different distractor-positioning guide design. All distracted experimental mandibles were scanned by CT imaging, then superimposed on a 3D simulation to get their discrepancy levels.
Results
The measured 3D distances between the reference landmarks of the surgical simulations and the experimental surgeries for the three groups were significantly different ( p < 0.0001) by statistical analysis. The errors were greater in the control group (with a total average of 19.18 ± 3.73 mm in 3D distance between the simulated and actual reference points) than those in the two experimental groups (with an average of 3.68 ± 1.41 mm for group 1 and 3.07 ± 1.39 mm for group 2). The customized distraction assembly with 3D-printed bone plate units in group 1 and 2, however, did not show any significant differences between simulated and actual distances ( p > 0.999).
Conclusion
Our newly-developed distraction assembly system with CAD/CAM plate for the distraction osteogenesis of the mandible produced a greater level of accuracy than that of a conventional distraction device. The system appears to address existing shortcomings of conventional distraction devices, including inaccuracy in vector-controlled movement of the system. However, it also needs to be further developed to address the requirements and anatomical characteristics of specific regions.
... Although VSP can be useful for predicting postsurgical outcomes, it has lower accuracy than bone predictions. Additionally, soft tissue remodeling issues may occur following hard tissue changes [49]. Accuracy of the Surgery 3D planning offers several advantages by providing detailed anatomical information about each patient [50]. ...
... 10 However, many assessments rely on measurements of volume, distance, and angles, 11,12 including evaluations from a frontal view. 13 With reconstructing occlusion, orthodontic, plastic, and oral surgery treatment goals need to be considered. 3D volumetric reconstruction images were created using CT for HFM patients under Le Fort I osteotomy of the maxilla and 3D bone distraction 14 of the affected side of the mandible. ...
Background
Surgical planning for hemifacial microsomia (HFM) patients often involves planning the amount of maxillary movement and mandibular bone distraction from three-dimensional (3D) volumetric images constructed from computed tomography scans. By representing anatomical indicators for facial symmetry in X, Y, and Z coordinates, we identified the more challenging areas in correcting facial asymmetry.
Methods
The study included five HFM patients with a mean age of 22.2 years, all diagnosed with HFM (type IIB). We established measurement points with high reproducible 3D coordinates on the 3D volumetric images obtained from computed tomography scans for before surgery, treatment objectives, and after surgery. We assessed the symmetry of measurement points between the affected side and nonaffected side at each time point.
Results
In the before-surgery group, significant differences were observed between the affected side and nonaffected side in X,Y (excluding Palatine foramen, upper molar, canine) and Z coordinates for measurement items. In the treatment objectives group, no differences were observed between the affected side and nonaffected side in X, Y, and Z coordinates, resulting in facial symmetry. In the after-surgery group, significant differences were observed in Y coordinates in the mental foramen area, and significant differences were observed in z axis measurement items in the canine and mental foramen areas.
Conclusions
It is evident that relying solely on a front view assessment is insufficient to achieve facial symmetry. Particularly, both anterior–posterior and vertical improvements in the area near the mental foramen on the affected side are necessary.
... Patients with HFM mainly manifest with mandibular hypoplasia, facial asymmetry, malocclusion, orbital anomalies, preauricular fistulas, microphthalmia, microtia, and macroglossia, which gravely impact patients' appearance and mentality [4,5]. The diversity and complexity of HFM make its treatment challenging, even for highly experienced surgeons [6]. Typically, the management of HFM requires a multidisciplinary and multistage approach. ...
Hemifacial Microsomia (HFM) is the second most common congenital craniofacial malformation syndrome, and the complexity of HFM makes its treatment challenging. The present study aimed to introduce a new approach of utilization of virtual surgical planning (VSP) and 3D-printed surgical adjuncts for maxillofacial reconstruction. Five HFM patients were included in this study. All participants were provided with a full VSP, including the design of osteotomy lines, the design and fabrication of 3D-printed cutting guides, fixation plates, and titanium mesh for implantation. With the assistance of 3D-printed cutting guides and fixation plates, the orbital deformities were corrected, and a 3D-printed titanium mesh combined with iliac cancellous bone graft was applied to reconstruct the zygomatic arch. The surgical accuracy, effectiveness, and bone absorption rate were evaluated. All patients completed the entirely digital treatment process without experiencing severe complications. The surgical adjuncts were effective in aligning the movement of the bone segments with the surgical plan, resulting in mean 3D deviations (1.0681 ± 0.15 mm) and maximum 3D deviations (3.1127 ± 0.44 mm). The image fusion results showed that the patients’ postoperative position of the maxilla, zygoma, and orbital rim was consistent with the virtual surgical plan, with only a slight increase in the area of bone grafting. The postoperative measurements showed significant improvement in the asymmetry indices of Er (AI of Er: from 17.91 ± 3.732 to 5.427 ± 1.389 mm, p = 0.0001) and FZ (AI of FZ: from 7.581 ± 1.435 to 4.070 ± 1.028 mm, p = 0.0009) points. In addition, the observed bone resorption rate at the 6-month follow-up across the five patients was 45.24% ± 3.13%. In conclusion, the application of VSP and 3D-printed surgical adjuncts demonstrates significant value in enhancing the precision and effectiveness of surgical treatments for HFM. A 3D-printed titanium mesh combined with iliac cancellous bone graft can be considered an ideal alternative for the reconstruction of the zygomatic arch.
... Virtual planning may be helpful to simulate the result after surgery, especially the position of the lips after orthognathic surgery, but has a lower precision when compared to the bones[19]. In some cases, soft tissue remodeling disharmony could occur after hard tissue changes[20]. ...
... VSP also acts as a treatment aid, assisting with everything from preoperative measurement and analysis through diagnostic and surgical design, intraoperative osteotomy, bone repositioning, rotation, and fixation (Wang et al., 2019). ...
Background: The accurate knowledge of the three-dimensional properties of the missing bone is necessary for the reconstruction of bony craniofacial deformities as a result of cancer procedures.
... Computer-aided radiology and surgery (CARS) uses navigation surgical instruments or three-dimensional (3D)-printed surgical apparatuses based on preoperative simulation surgery and 3D skeletal analysis using maxillofacial computed tomography (CT). 1 Currently, CARS is being applied in clinical practice. ...
Background
This study was conducted to evaluate the accuracy of navigation process according to the type of tracking methods and registration markers. The target registration errors (TREs) were measured at seven anatomical landmarks of the mandible for evaluation.
Methods
Four different experiments were performed to obtain the TREs using two different tracking methods, the optical tracker (Polaris) and the electromagnetic (EM) tracker (Aurora), and two different types of registration markers, invasive and noninvasive markers. All comparisons of TREs were statistically analyzed using SPSS and Python-based statistical package (Pingouin).
Results
The average TRE values obtained from the four different experiments were as follows: 1) 0.85 mm using invasive marker and Aurora, 2) 1.06 mm using invasive marker and Polaris, 3) 1.43 mm using noninvasive marker and Aurora, and 4) 1.57 mm using noninvasive marker and Polaris. All comparisons among the type of markers and the seven anatomical landmarks revealed statistically significant differences, except for the type of tracking system. Although the comparison between the modality of the tracking system showed no significant differences, the EM-based approach consistently demonstrated better performances than the optical type in all comparisons.
Conclusions
This study demonstrates that, irrespective of the tracking modality, the invasive marker is a better choice in terms of accuracy. When using the noninvasive marker, it is important to consider the increased TREs. In the present study, the noninvasive marker caused a maximum increment of TREs of approximately 0.81 mm compared with the invasive marker. Furthermore, EM-based tracking using an invasive marker may result in the best accuracy for the mandible.
... In recent year, virtual three-dimensional surgical planning and guidance was promising tool for accurate treatment planning and sufficient surgical result in the treatment of adult hemifacial macrosomia patients. 13,14 This means that accurate prognosis for hemifacial microsomia treatment may contribute to the avoidance of the repeated distraction and/or osteotomy. ...
Aim: To present a growing patient with unilateral mandibular hypoplasia and microtia involved in the first and second branchial arch syndrome (FSBAS) treated with functional appliance.
Background: The FSBAS comprises several developmental facial hypoplasia in ear and maxillofacial bones, resulting in hemifacial microsomia. Treatment for hemifacial microsomia varies greatly depending on the grade of mandibular deformities. Functional appliance treatment during growth period is available for mild to moderate mandibular deformities. However, there are few reports of hemifacial microsomia treated with functional appliance.
Case description: The patient, an 8 years and 5 months old girl, had a chief complaint of mandibular deviation. She had been diagnosed with the FSBAS at birth. Her facial profile was straight and panoramic radiograph indicated that the mandibular ramal height of the affected side was about 60.4% compared to the unaffected side. The occlusal cant was 6o, and the right maxilla and mandible showed severe growth deficiency. At the age of 10 years, functional appliance with expander was used; for 2 years 6 months, the maxillomandibular growth was controlled and from panoramic radiograph, the ramus height of the affected side was increased to 65.0% compared to the unaffected left mandibular ramus. At the age of 12 years and 8 months, multibracket treatment was initiated. After 32 months of active treatment, proper occlusion with functional Class I canine and molar relationships was obtained although facial asymmetry associated with the difference of ramus heights still existed. The resulting occlusion was stable during 1.5-year retention period.
Conclusion: Our results indicated the importance of orthopedic treatment during growth period in the patient with hemifacial microsomia involving the FSBAS.
Clinical significance: This report proposes an efficacy of conventional orthodontic treatment for growing patients with hemifacial microsomia involved in FSBAS.
... Both MDO and orthognathic surgery can treat micrognathia effectively. 3 Recently, MDO has become one of the most popular methods for the correction of craniofacial deformities, particularly for treatment of OSAS in TMJa. 5 One of the most important advantages of MDO is the lower risk of relapse, on account of the slow adaptation of the soft tissue (muscle, blood vessels, nerves, skin) to the gradual incremental mandibular advancement and it applies a milder load to the temporomandibular joints. MDO is more suitable than traditional orthognathic surgery when larger advancements are needed (>7 mm). ...
We reported a 16-year-old patient with chin defect accompanying micrognathia and airway stenosis owing to a traffic accident. The treatment of this patient involved a modified genioplasty associated with orthognathic surgeries. Through data analysis, we found that the patient's facial morphology and airway space are greatly improved compared with preoperation: y-axis(T4-T1) = -4.5 degree; FCA (T4-T1) = -18 degree; CSAmin(T4-T1) = 227 mm. In conclusion, the modified genioplasty associated with orthognathic surgeries is an effective way to reshape the defected chin and treat micrognathia and airway stenosis in this case.
... In terms of accuracy, the literature is clear to provide information regarding the precision of the VSP compared to traditional methods [16,17], especially for asymmetric cases [18], showing exceptional results. ...
Orthognathic surgeries have had their surgical planning carried out in an analogue manner for a long time. However, with the advancement and popularization of technologies, surgeries began to be planned virtually, using intra-oral scanning, computed tomography, and software that simulates the steps, and the final result, also providing surgical guides that help to increase precision throughout the execution of the procedure. 3D planning may present some obstacles to its implementation, such as its high cost and the need for greater training of the surgeon team. Therefore, the objective of this work is to carry out a systematic review to evaluate and synthesize studies on virtual planning in orthognathic surgeries.
Objective:
To investigate condylar bone density (BD) in children with craniofacial microsomia (CFM) and identify factors that contribute to early stage condylar resorption (CR) after mandibular distraction osteogenesis (MDO).
Design:
Retrospective study.
Setting:
Craniofacial department of a plastic surgery hospital.
Patients:
Fifty-one children with CFM classified as Pruzansky IIa based on complete pre-(T0) and post-MDO (T1) computed tomography (CT) data.
Intervention and main outcome measurements:
Mimic 21.0 (Materialise Inc., Belgium) was used to measure bilateral BD and condylar height (CH) and volume (CV) of affected side. Children were split into groups based on either affected side BD or the distraction length (DL,25 mm as cutoff) .Bilateral BD was compared using a paired t-test in each group. The CH and CV of affected side at T0 and T1 were compared. The relative values of the CH and CV (CH ratio) and the volume (CV ratio) of the affected side were compared across the groups.
Results:
The BD was lower on affected side than on unaffected side. Regarding BD, CH and CV decreased after MDO in group I, while the CH ratio and CV ratio of group I was lower than that of groups II and III. Regarding DL, the CV ratio was lower in Group L than Group S.
Conclusions:
The condylar bone quality on affected side is compromised in type IIa CFM. A low BD in combination with a larger distraction distance may increase the risk of CR; therefore, MDO in patients with such characteristics should be postponed.
Craniomaxillofacial surgery has been experiencing a deep conceptual change in surgical planning over the last decade, with virtual reality technologies becoming widely adopted. The high demand has led to an exponential increase in available software. The aim of this review was to outline the current literature and provide evidence on the most used software for virtual surgical planning (VSP), and also to define contemporary knowledge on which procedures are more ready candidates for VSP. A search was performed in the major databases, and screening of the results according to the PRISMA statement identified 535 articles reporting the implementation of preoperative VSP during the years 2010-2020. A total of 77 different software programs were identified. The surgical procedures were assigned a standardized nomenclature and further simplified into 10 categories for analysis: temporomandibular joint (TMJ), implants (IMPL), malformations (MALF), reconstruction (REC), oncology (ONCO), oral surgery (ORAL), orthognathic surgery (ORTH), cranial surgery (CRANIO), trauma (TRAUMA), miscellaneous (OTHER). The journals they were reported in and the sample size of each study were also investigated. The results showed that the Materialise suite was the most widespread tool for VSP, with a prevalence of 36.3%, followed by the Geomagic family. Several packages were found to be associated with a specific type of surgical procedure. This review offers a synopsis of the array of VSP software reported in the literature and sets the basis for an informed, evidence-based use of this software in craniomaxillofacial surgery.
Objectives:
This study was conducted to evaluate the accuracy of navigation process according to the type of tracking methods and registration markers. The target registration errors (TREs) were measured at seven anatomical landmarks of the mandible.
Methods:
Four different experiments were performed to obtain the TREs using two tracking methods, the optical tracker (Polaris) and the electromagnetic (EM) tracker (Aurora), and two types of registration markers, invasive and noninvasive markers. All comparisons of TREs were statistically analyzed using SPSS and Python-based statistical package.
Results:
The average TRE values obtained from the four experiments were as follows: (1) 0.85 mm (± 0.07) using invasive marker and Aurora, (2) 1.06 mm (± 0.12) using invasive marker and Polaris, (3) 1.43 mm (± 0.15) using noninvasive marker and Aurora, and (4) 1.57 mm (± 0.23) using noninvasive marker and Polaris. Comparisons between all the experimental results revealed statistically significant differences except for the type of tracking system. Although the comparison between the modality of the tracking system showed no significant differences, the EM-based approach consistently demonstrated better performances than the optical type in all comparisons.
Conclusions:
This study demonstrates that irrespective of the tracking modality, using invasive marker is a better choice in terms of accuracy. When using noninvasive marker, it is important to consider the increased TREs. In this study, the noninvasive marker caused a maximum increment of TREs of 0.81 mm compared with the invasive marker. Furthermore, using an EM-based tracker with invasive marker may result in the best accuracy for navigation.
This is a retrospective study to evaluate the postsurgical position of the maxilla and mandible in 5 matured craniofacial patients with unilateral craniofacial microsomia who underwent 2 jaw surgical procedures using computerized surgical planning. The craniofacial surgeon and orthodontist completed the virtual surgical treatment plan with a biomedical engineer's assistance via a web meeting. The treatment plan of each patient included 2 jaw surgery with genioplasty. At the maxillary dental midline, the planned mean advancement was 4 mm; yaw, a rotational correction towards the unaffected side was 4.96 mm; and impaction was 2.74 mm. The mean advancement measured at point B was 10.5 mm, and the rotational correction towards the unaffected side was 6.58 mm. The mean advancement following genioplasty was 8.43 mm, and the mean transverse correction was 6.33 mm towards the midsagittal plane. The intermediate surgical splint, final surgical splint, bone graft templates, and cutting guides were constructed utilizing computer-aided design/computer-aided manufacturing technology. The surgeon executed the treatment plan in the operating room using appropriate computer-generated guides and splints. A postsurgical cone-beam computed tomography scan was obtained and superimposed on the surgical treatment plan using Simplant OMS 10.1 software. The cranial base was used as a reference for superimposition. Three-dimensional color-coded displacement maps were generated to visually and quantitatively assess the surgical outcome. There was a mean error of 0.88 mm (+0.30) for the position of the maxillary anatomical structures from the planned position, and the anterior mandibular anatomical structures were on average 0.96 mm (+0.26) from the planned position.
Purpose:
Pruzansky-Kaban III hemifacial microsomia (HFM) is a rare congenital facial deformity, and it is challenging to reconstruct the facial appearance. The aim of the present study was to describe a technique of application of virtual planning for three-dimensional (3D) guided maxillofacial reconstruction of Pruzansky-Kaban III HFM using custom made fixation plate.
Methods:
With the help of 3D models, a preoperative virtual planning and surgical simulation were performed. Computer-aided design/computer-aided manufacture (CAD/CAM) patient customized guides and custom fixation plates were designed to reconstruct the maxillofacial skull intraoperatively. Assessment was achieved through evaluation of the postoperative effects, such as imaging, facial appearance recovery and operation time.
Results:
Five patients with Pruzansky-Kaban III HFM were enrolled into this study. The results showed an exceptional accuracy between the preoperative virtual planning and the outcomes actually achieved postoperatively. Intraoperative measurements were no longer needed and the different surgical steps became more simple and easier. The total time was distributed as: 160 minutes for the surgical time, 40 minutes for preoperative virtual plan, and 80 minutes for designing the patient specific cutting guides and custom fixation plates. The operating time and tissue damage were reduced. All cases underwent uneventful healing without any complications.
Conclusion:
The technique of patient specific guides and custom fixation plates is a reliable method of conveying the virtual plan to the operative field with higher efficiency in patients with Pruzansky-Kaban III HFM.
Hemifacial microsomia is a congenital malformation that involves the underdevelopment of the mandible and the ear leading to facial asymmetry. Distraction osteogenesis is the gold standard surgical procedure for severe cases of hemifacial microsomia in which two sectioned bone parts are lengthened gradually to promote bony infill. The final shape of the bone depends on the position of the distractor and the vector of distraction. This article presents a complex clinical case of a 7-year-old patient with severe hemifacial microsomia that required distraction to correct mandibular asymmetry. Digital technology was applied to virtually plan the surgery pre-operatively. Optimal symmetrisation required a vertical vector of distraction that none of the ‘off-the-shelf’ distractors could provide. Consequently, a three-dimensional printed titanium implant was designed as a spacer to be attached to the inferior plate of a standard distractor, allowing the achievement of a vertical vector. By adding the spacer, the inferior footplate of the distractor was not directly fixed to bone and the vector of distraction was not dictated by the anatomical contour of the patient but by the shape of the spacer. Surgical guides were created to translate the virtual plan to the operating room. The guides prevented potential damage to tooth buds and the inferior alveolar nerve. This article describes the three-dimensional computer-aided design and additive manufacture of the custom devices that delivered the following: (1) symmetrisation of the mandible after distraction surgery without manipulation of the healthy side of the mandible; (2) a feasible and safer surgical solution; and (3) an innovative method that enables a wider range of vectors of distraction, bringing new prospects to the treatment of distraction osteogenesis in the future.
The aim of this retrospective study was to use computer-aided design and manufacturing (CAD/CAM) patient-specific plates and cutting guides for the waferless positioning and fixation of the maxilla after bimaxillary osteotomies in cases of hemifacial microsomia with condylar dysplasia or absence of the temporomandibular joint (TMJ), and to compare the results with the CAD/CAM fabricated surgical wafer by 3-dimensional analysis. Eighteen patients were selected from the hospital database, preoperative surgical planning and simulation were done on 3-dimensional computed tomographic models for all patients, and they were divided into Group I – in which CAD/CAM patient-specific cutting guides and plates were used; and Group II – in which CAD/CAM fabricated surgical wafers were used. Finally, the outcome was evaluated by comparing planned with postoperative outcomes. The largest discrepancies of the Le Fort I segment were 0.50 (0.18) mm in the anteroposterior direction and 0.82 (0.60)° in the yaw orientation with Group I. The largest discrepancies of the Le Fort I segment were 1.32 (1.40) mm in superioinferior direction and 8.48 (7.73)° in the yaw orientation with Group II. The CAD/CAM patient-specific cutting guides and plates proved to be reliable and have great value in improving the accuracy in repositioning the Le Fort I segment and in the efficacy of orthognathic treatment of hemifacial microsomia with condylar dysplasia or no TMJ. The CAD/CAM patient-specific cutting guides and plates are therefore a useful alternative to the wafer technique.
Clinicians use different diagnostic terms for patients with underdevelopment of facial features arising from the embryonic first and second pharyngeal arches, including first and second branchial arch syndrome, otomandibular dysostosis, oculoauriculovertebral syndrome, and hemifacial microsomia. Craniofacial microsomia has become the preferred term. Although no diagnostic criteria for craniofacial microsomia exist, most patients have a degree of underdevelopment of the mandible, maxilla, ear, orbit, facial soft tissue, and/or facial nerve. These anomalies can affect feeding, compromise the airway, alter facial movement, disrupt hearing, and alter facial appearance.
The benefit of computer-assisted planning in orthognathic surgery has been extensively documented over the last decade. This study aims to evaluate the accuracy of a virtual orthognathic surgical plan by a novel three dimensional (3D) analysis method. Ten patients who required orthognathic surgery were included in this study. A virtual surgical plan was achieved by the combination of a 3D skull model acquired from computed tomography (CT) and surface scanning of the upper and lower dental arch respectively and final occlusal position. Osteotomies and movement of maxilla and mandible were simulated by Dolphin Imaging 11.8 Premium(®) (Dolphin Imaging and Management Solutions, Chatsworth, CA). The surgical plan was transferred to surgical splints fabricated by means of Computer Aided Design/Computer Aided Manufacturing (CAD/CAM). Differences of three dimensional measurements between the virtual surgical plan and postoperative results were evaluated. The results from all parameters showed that the virtual surgical plans were successfully transferred by the assistance of CAD/CAM fabricated surgical splint. Wilcoxon's signed rank test showed that no statistically significant deviation between surgical plan and post-operational result could be detected. However, deviation of angle U1 axis-HP and distance of A-CP could not fulfill the clinical success criteria. Virtual surgical planning and CAD/CAM fabricated surgical splint are proven to facilitate treatment planning and offer an accurate surgical result in orthognathic surgery.
The purpose of this study was to clarify the correlation between pre-treatment anterior disc displacement and mandibular stability after orthognathic and orthodontic treatment among patients with a skeletal class II malocclusion and without pre-treatment condylar resorption. Thirty-seven patients were included (7 male, 30 female). The mean length of follow-up was 6.76±3.06 years. Patients with condylar resorption before treatment were excluded. Magnetic resonance images and lateral cephalometric radiographs were taken before treatment (T0), after treatment (T1), and at follow-up (T2). Patients were classified according to the degree of disc displacement: -10-10° 'normal', 11-50° 'slight to mild', ≥51° 'moderate to severe'. Results showed the condyle moved posterosuperiorly after treatment, and then moved anteriorly to a more concentric location during the long follow-up period. Condylar movement was found not to correlate with disc displacement. The degree of disc displacement before treatment did not correlate with the post-surgical mandibular positional change in either the sagittal or vertical direction. To conclude, the mandibular bilateral sagittal split ramus osteotomy was stable in the long-term after orthognathic and orthodontic treatment. In the absence of pre-treatment condylar resorption, the degree of initial anterior disc displacement did not have a significant influence on the stability of mandibular advancement.
Hemifacial microsomia is a deformity of variable expressivity with unilateral hypoplasia of the mandible and the ear. In this study, we evaluated skeletal soft tissue changes after bimaxillary unilateral vertical distraction.
Eight patients (4 preadolescents 4 adolescents) each with a grade II mandibular deformity underwent a LeFort I osteotomy and an ipsilateral horizontal mandibular ramus osteotomy. A semiburied distraction device was placed over the ramus, and intermaxillary fixation was applied. Anteroposterior cephalometric and frontal photographic analyses were conducted before and after distraction. Statistics were used to analyze the preoperative and postoperative changes.
Cephalometrically, the nasal floor and the occlusal and gonial plane angles decreased. The ratios of affected-unaffected ramus and gonial angle heights improved by 15% and 20%, respectively. The position of menton moved toward the midline. The photographic analysis showed a decrease of the nasal and commissure plane angles, and the chin moved to the unaffected side. The parallelism between the horizontal skeletal and soft tissue planes improved, with an increase in the affected side ramus height and correction of the chin point toward the midline.
Simultaneous maxillary and mandibular distraction improved facial balance and symmetry. Patients in the permanent dentition with fixed orthodontic appliances and well-aligned dental arches responded well to this intervention.
Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.
Background
Within the domain of craniomaxillofacial surgery, orthognathic surgery is a special field dedicated to the correction of dentofacial anomalies resulting from skeletal malocclusion. Generally, in such cases, an interdisciplinary orthodontic and surgical treatment approach is required. After initial orthodontic alignment of the dental arches, skeletal discrepancies of the jaws can be corrected by distinct surgical strategies and procedures in order to achieve correct occlusal relations, as well as facial balance and harmony within individualized treatment concepts. To transfer the preoperative surgical planning and reposition the mobilized dental arches with optimal occlusal relations, surgical splints are typically used. For this purpose, different strategies have been described which use one or more splints. Traditionally, these splints are manufactured by a dental technician based on patient-specific dental casts; however, computer-assisted technologies have gained increasing importance with respect to preoperative planning and its subsequent surgical transfer.
Methods
: In a pilot study of 10 patients undergoing orthognathic corrections by a one-splint strategy, two final occlusal splints were produced for each patient and compared with respect to their clinical usability. One splint was manufactured in the traditional way by a dental technician according to the preoperative surgical planning. After performing a CBCT scan of the patient’s dental casts, a second splint was designed virtually by an engineer and surgeon working together, according to the desired final occlusion. For this purpose, RapidSplint®, a custom-made software platform, was used. After post-processing and conversion of the datasets into .stl files, the splints were fabricated by the PolyJet procedure using photo polymerization. During surgery, both splints were inserted after mobilization of the dental arches then compared with respect to their clinical usability according to the occlusal fitting.
Results
Using the workflow described above, virtual splints could be designed and manufactured for all patients in this pilot study. Eight of 10 virtual splints could be used clinically to achieve and maintain final occlusion after orthognathic surgery. In two cases virtual splints were not usable due to insufficient occlusal fitting, and even two of the traditional splints were not clinically usable. In five patients where both types of splints were available, their occlusal fitting was assessed as being equivalent, and in one case the virtual splint showed even better occlusal fitting than the traditional splint. In one case where no traditional splint was available, the virtual splint proved to be helpful in achieving the final occlusion.
Conclusions
In this pilot study it was demonstrated that clinically usable splints for orthognathic surgery can be produced by computer-assisted technology. Virtual splint design was realized by RapidSplint®, an in-house software platform which might contribute in future to shorten preoperative workflows for the production of orthognathic surgical splints.
Hemifacial microsomia is a hypoplastic disorder of the first and second branchial arches that significantly impacts on the development of the jaws, leading to malocclusion and facial asymmetry. There is little in the literature regarding the application of orthodontic/orthognathic approaches to the correction of these deformities and the stability of the surgical results. To address this, a retrospective chart review of 10 patients with complete orthodontic records and greater than 1 year of follow-up was performed. Posteroanterior cephalograms were assessed by modified Grummons analysis to determine mandibular offset (deviation of the chin point fromthe skeletalmidline) and occlusal cant. These measurementswere performed at 3 time points (T1: preoperative, T2: immediate postoperative, T3: follow-up) to elucidate the surgicalmovement (T2-T1), the postoperative relapse (T3-T2), and the net gain movement (T3-T1). Maxillary movements were quantified, and the occlusal cant was expressed as a ratio between vertical heights of the maxilla at the first molar on each side. One sample t test demonstrated statistically significant surgical movement and net gain. Relapse was statistically insignificant. Repeated-measures analysis of variance demonstrated similar results for chin point position relative to the putative midline. Our results suggest that a combined orthodontic/orthognathic approach at skeletal maturity delivers improved occlusal outcomes in the long term as assessed by chin point deviation and occlusal cant, but secondary surgery rates are higher than those for orthognathic surgery in other patient groups. We advocate limiting surgery to skeletalmaturity whenever possible to achieve stable long-term results while limiting morbidity and number of procedures.
To explore a new surgical approach for chin augmentation using a prosthesis with 3 intraoral vertical incisions whereby placement of the prosthesis is more convenient and accurate, with fewer postoperative complications. Following the anatomic characteristics of the chin, a bilateral mucosal vertical incision and a median observation incision are made. The V-shaped mark on the upper side of the prosthesis can be seen through the observation incision after it is placed from the lateral incision into the predesigned compartment. The incision can be sutured if there is no bleeding in the operation area. Surgery performed in all 19 patients with mild microgenia with 6 to 12 months of follow-up resulted in satisfactory chin and face shape without any complications. The application of this novel method can correct McCarthy type I microgenia with more accurate positioning, less possibility of bilateral sideways and/or up/down movement, and fewer complications.
Objective:
Compared with conventional two-dimensional (2D) planning, three-dimensional (3D) planning in orthognathic surgery yields more accurate anatomical information and enables the precise positioning of maxillary and mandibular segments, particularly for patients with facial asymmetry. Accordingly, surgical outcomes achieved using 3D planning should be superior. This study determined the differences between the 2D and 3D planning techniques by comparing their surgical outcomes.
Materials and methods:
In this retrospective study, patients who underwent surgery following the traditional 2D planning technique were classified into the 2D planning group. Patients in whom the 2D plan was transferred to a 3D system after surgical simulation were classified into the 3D planning group. Surgical outcomes were compared using cephalometric measurements and patient perception of the results.
Results:
In the 3D planning group, more favorable results were observed in frontal symmetry, change in the angle between the orbital and occlusal lines, frontal ramus inclination, and the distances from the mandibular central incisor and menton to the midsagittal line. No significant differences were observed in the lateral profiles (SNA, SNB, ANB, and angle convexity) of the two groups. Patient satisfaction was favorable in the two groups, but more patients in the 3D planning group reported being very satisfied.
Conclusion:
The 3D planning technique provided superior overall outcomes. The study findings can be used to augment clinical planning and surgical execution when using a conventional approach.
Purpose:
Repair of the mandibular deformity in hemifacial microsomia (HFM) remains controversial, and there is scant information in the literature regarding the late outcomes. The aim of this study was to evaluate architectural and aesthetic long-term outcomes for primary mandibular surgery in patients with HFM.
Materials and methods:
Thirty-nine patients with types II and type III HFM were included in this retrospective study. Depending on the nature of the mandibular deformity, patients were treated using a costochondral graft (CCG) or a vertical ramus osteotomy (VRO). Architectural and aesthetic parameters were evaluated preoperatively, postoperatively, and at the end of the follow-up period.
Results:
The architectural analysis revealed the restoration of a level occlusal canting at the end of the follow-up period (p < 0.0001); the chin deviation was corrected immediately by the surgery, although a trend to recurrence was noted at the last follow-up evaluation (p < 0.0001). The aesthetic assessment revealed a significant improvement of the chin deflection, and correction of the lip commissural line tilt (p < 0.0001). Twenty-three percent of the patients required an additional orthognathic revision.
Conclusion:
CCG and VRO continue to be suitable and safe procedures with good outcomes that allow a single-stage correction of occlusion and preservation of mandibular growth in young patients with type II and type III HFM.
Purpose:
To investigate the application of computer-assisted surgical planning and virtual guide in distraction osteogenesis for patients with hemifacial microsomia.
Methods:
Eight patients diagnosed with unilateral hemifacial microsomia were enrolled in this study. Preoperative surgical planning and simulation were performed on three-dimensional model. Distraction was simulated on virtual model and the new morphology of the mandible was predicted. Mandibular ramus osteotomy and distractor implant was performed under the guidance of tooth-borne virtual guide. Postoperative evaluation of the intervention was performed by comparison of surgical planning and actual result.
Results:
Preoperative planning, simulation, osteotomy and distractor implant under the guidance of virtual guide were performed successfully on all patients. Tooth-borne guide defined the osteotomy line and accurate position of distractor. Facial symmetry was greatly improved. The osteogenesis and neomandible contour was checked by postoperative computed tomography, and a good matching with the preoperative planning was achieved.
Conclusions:
Computer-assisted surgical planning and intraoperative virtual guide shows its great value in improving the accuracy of distraction osteogenesis and restoring facial symmetry. It is regarded as a valuable technique in this potentially complicated procedure.
Objective:
This study aims to evaluate the accuracy of virtual surgical planning in two-jaw orthognathic surgery via quantitative comparison of preoperative planned and postoperative actual skull models.
Study design:
Thirty consecutive patients who required two-jaw orthognathic surgery were included. A composite skull model was reconstructed by using Digital Imaging and Communications in Medicine (DICOM) data from spiral computed tomography (CT) and STL (stereolithography) data from surface scanning of the dental arch. LeFort I osteotomy of the maxilla and bilateral sagittal split ramus osteotomy (of the mandible were simulated by using Dolphin Imaging 11.7 Premium (Dolphin Imaging and Management Solutions, Chatsworth, CA). Genioplasty was performed, if indicated. The virtual plan was then transferred to the operation room by using three-dimensional (3-D)-printed surgical templates. Linear and angular differences between virtually simulated and postoperative skull models were evaluated.
Results:
The virtual surgical planning was successfully transferred to actual surgery with the help of 3-D-printed surgical templates. All patients were satisfied with the postoperative facial profile and occlusion. The overall mean linear difference was 0.81 mm (0.71 mm for the maxilla and 0.91 mm for the mandible); and the overall mean angular difference was 0.95 degrees.
Conclusions:
Virtual surgical planning and 3-D-printed surgical templates facilitated the diagnosis, treatment planning, and accurate repositioning of bony segments in two-jaw orthognathic surgery.
Craniofacial microsomia encompasses a spectrum of diagnoses associated with variable degrees of mandibular hypoplasia, facial asymmetry, chin deviation, occlusal abnormalities, and potential airway compromise. This study presents one surgeon's experience with costochondral rib grafting for mandibular reconstruction in children with Pruzansky/Kaban type 2B and type 3 mandibular hypoplasia.
An institutional review board-approved retrospective chart review was performed of all patients with craniofacial microsomia who underwent costochondral rib grafting for mandibular reconstruction performed by the senior author (S.P.B.) at The Children's Hospital of Philadelphia from January of 1998 to September of 2013. Demographic information, surgical history, operative details, postoperative complications, and outcomes were recorded. Plain radiographs and preoperative and postoperative three-dimensional computed tomographic scans were reviewed.
Two hundred fifty-five patients were diagnosed with craniofacial microsomia, and 22 patients met inclusion criteria. Twelve boys and 10 girls underwent grafting at an average age of 7.2 years. Thirty-three costochondral rib grafts were performed, 11 unilateral reconstructions and 11 bilateral reconstructions. Twelve hemimandibles were type 2B and 21 were type 3. No intraoperative complications were reported, and no incidence of graft resorption was noted. No additional procedures were required in 27 reconstructed hemimandibles (81.8 percent), whereas six (18.2 percent) required secondary distraction osteogenesis. Only one patient developed postoperative ankylosis. No malunion or nonunion was noted.
The approach described in this article allowed the authors to obtain reliably good results with costochondral rib grafting for type 2B and type 3 mandibular hypoplasia associated with craniofacial microsomia.
Therapeutic, IV.
The purpose of the study is to present and discuss a workflow regarding computer-assisted surgical planning for bimaxillary surgery and intermediate splint fabrication. This study describes a protocol starting from wax bite registration to fabrication of the necessary intermediate splint. The procedure is a proof of concept to replace not only the model surgery but also facebow registration and transfer from facebow to articulator. Three different modalities were utilized to obtain this goal: cone beam computed tomography (CBCT), optical dental scanning, and 3-dimensional printing. A universal registration block was designed to register the optical scan of the wax bite to the CBCT data set. Integration of the wax bite avoided problems related to artifacts caused by dental fillings in the occlusal plane of the CBCT scan. Fifteen patients underwent bimaxillary orthognathic surgery. The printed intermediate splint was used during the operation for each patient. A postoperative CBCT scan was taken and registered to the preoperative CBCT scan. The difference between the planned and the actual bony surgical movement at the edge of the upper central incisor was 0.50 ± 0.22 mm in sagittal, 0.57 ± 0.35 mm in vertical, and 0.38 ± 0.35 mm in horizontal direction (midlines). There was no significant difference between the planned and the actual surgical movement in 3 dimensions: sagittal (P = 0.10), vertical (P = 0.69), and horizontal (P = 0.83). In conclusion, under clinical circumstances, the accuracy of the designed intermediate splint satisfied the requirements for bimaxillary surgery.
There may well be a shift towards 3-dimensional orthognathic surgery when virtual surgical planning can be applied clinically. We present a computer-assisted protocol that uses surgical navigation supplemented by an interactive image-guided visualisation display (IGVD) to transfer virtual maxillary planning precisely. The aim of this study was to analyse its accuracy and versatility in vivo. The protocol consists of maxillofacial imaging, diagnosis, planning of virtual treatment, and intraoperative surgical transfer using an IGV display. The advantage of the interactive IGV display is that the virtually planned maxilla and its real position can be completely superimposed during operation through a video graphics array (VGA) camera, thereby augmenting the surgeon's 3-dimensional perception. Sixteen adult class III patients were treated with by bimaxillary osteotomy. Seven hard tissue variables were chosen to compare (ΔT1-T0) the virtual maxillary planning (T0) with the postoperative result (T1) using 3-dimensional cephalometry. Clinically acceptable precision for the surgical planning transfer of the maxilla (<0.35mm) was seen in the anteroposterior and mediolateral angles, and in relation to the skull base (<0.35°), and marginal precision was seen in the orthogonal dimension (<0.64mm). An interactive IGV display complemented surgical navigation, augmented virtual and real-time reality, and provided a precise technique of waferless stereotactic maxillary positioning, which may offer an alternative approach to the use of arbitrary splints and 2-dimensional orthognathic planning.
Use of the free groin flap, one of the first microvascular free flaps described, has been neglected recently because it has a short pedicle and varies anatomically. However, we have found its anatomical features and type of tissue ideal for volumetric enhancement in severe hemifacial asymmetry. We present a retrospective review of a consecutive series of 14 patients who had hemifacial augmentation with a free groin flap (mean age at operation 17 years, range 10-42) since 2001, and discuss the surgical technique. The most common cause of asymmetry was hemifacial microsomia (n=6). Anatomical variation of the vessels in the groin did not cause problems. Arterial anastomosis was to the facial artery in 13 patients; 12 patients had simultaneous hard tissue procedures. No flaps failed. The free groin flap is a useful adjunct in the management of hemifacial deficits in volume when free fat grafts will not provide enough bulk. Although the operation can take longer than non-vascularised grafts, little tissue is lost so long-term results may be more predictable. We have found the anatomy fairly consistent and the short pedicle caused no problems.
Currently, simultaneous maxillomandibular distraction osteogenesis is a standard procedure for the correction of hemifacial microsomia. Many variations of the procedure have been reported. However, a common problem has been the extended duration of the procedure. In particular, the lengthy intermaxillary fixation period includes a prolonged distraction series that requires the restriction of oral food intake and creates significant stress for the patient, which has a profound effect on patient satisfaction. To avoid this stress, we have developed tandem osteotomy with distraction osteogenesis, termed the TODO procedure. The TODO procedure not only shortens the intermaxillary fixation period and the duration of therapy but also creates the ideal skeletal proportions, with horizontalization of the occlusal plane. The TODO procedure has the added benefit of producing a marked aesthetic improvement. The patient was extremely satisfied by the result and endured minimal stress.
Purpose:
The purpose of this prospective multicenter study was to assess the accuracy of a computer-aided surgical simulation (CASS) protocol for orthognathic surgery.
Materials and methods:
The accuracy of the CASS protocol was assessed by comparing planned outcomes with postoperative outcomes of 65 consecutive patients enrolled from 3 centers. Computer-generated surgical splints were used for all patients. For the genioplasty, 1 center used computer-generated chin templates to reposition the chin segment only for patients with asymmetry. Standard intraoperative measurements were used without the chin templates for the remaining patients. The primary outcome measurements were the linear and angular differences for the maxilla, mandible, and chin when the planned and postoperative models were registered at the cranium. The secondary outcome measurements were the maxillary dental midline difference between the planned and postoperative positions and the linear and angular differences of the chin segment between the groups with and without the use of the template. The latter were measured when the planned and postoperative models were registered at the mandibular body. Statistical analyses were performed, and the accuracy was reported using root mean square deviation (RMSD) and the Bland-Altman method for assessing measurement agreement.
Results:
In the primary outcome measurements, there was no statistically significant difference among the 3 centers for the maxilla and mandible. The largest RMSDs were 1.0 mm and 1.5° for the maxilla and 1.1 mm and 1.8° for the mandible. For the chin, there was a statistically significant difference between the groups with and without the use of the chin template. The chin template group showed excellent accuracy, with the largest positional RMSD of 1.0 mm and the largest orientation RMSD of 2.2°. However, larger variances were observed in the group not using the chin template. This was significant in the anteroposterior and superoinferior directions and the in pitch and yaw orientations. In the secondary outcome measurements, the RMSD of the maxillary dental midline positions was 0.9 mm. When registered at the body of the mandible, the linear and angular differences of the chin segment between the groups with and without the use of the chin template were consistent with the results found in the primary outcome measurements.
Conclusions:
Using this computer-aided surgical simulation protocol, the computerized plan can be transferred accurately and consistently to the patient to position the maxilla and mandible at the time of surgery. The computer-generated chin template provides greater accuracy in repositioning the chin segment than the intraoperative measurements.
We present a virtual planning protocol incorporating a patented 3-surgical splint technique for orthognathic surgery. The purpose of this investigation was to demonstrate the feasibility and validity of the method in vivo.
The protocol consisted of (1) computed tomography (CT) or cone-beam computed tomography (CBCT) maxillofacial imaging, optical scan of articulated dental study models, segmentation, and fusion; (2) diagnosis and virtual treatment planning; (3) computed-assisted design and manufacture (CAD/CAM) of the surgical splints; and (4) intraoperative surgical transfer. Validation of the accuracy of the technique was investigated by applying the protocol to 8 adult class III patients treated with bimaxillary osteotomies. The virtual plan was compared with the postoperative surgical result using image fusion of CT/CBCT dataset by analysis of measurements between hard and soft tissue landmarks relative to reference planes.
The virtual planning approach showed clinically acceptable precision for the position of the maxilla (<0.23 mm) and condyle (<0.19 mm), marginal precision for the mandible (<0.33 mm), and low precision for the soft tissue (<2.52 mm).
Virtual diagnosis, planning, and use of a patented CAD/CAM surgical splint technique provides a reliable method that may offer an alternate approach to the use of arbitrary splints and 2-dimensional planning.
The purpose of this study was to evaluate the error magnitude in the clinical application of face-bow devices. Technical and methodologic inaccuracies, as well as deviations from reference planes, were determined.
The presented method is part of a 3-dimensional virtual planning procedure for orthognathic surgery and included 15 patients with dentoskeletal deformities. Cone beam computed tomography datasets obtained from patients with a referenced face-bow plane and a centric registration splint were matched with cone beam computed tomography datasets of the registered plaster model of the maxilla mounted in an articulator. To assess potential sources of methodologic errors, angulations were measured between the virtual face-bow plane and the horizontal cross bar of the virtual articulator. To evaluate the reproducibility of the anatomic reference plane, angulations between the Frankfort plane and the horizontal cross bar of the articulator were measured. Statistical significance was set at P < .05 and tested by univariate analysis of variance.
Technical and methodologic errors showed a mean deviation of 3.5°, with a median of 3.6° and SD of 2.7°. The values did not reach statistical significance (P = .1). However, there was a significant error (P < .05) in determining the position of the anatomic reference plane by face-bow transfer. The mean deviation was 7.7° (values ranged between 1.2° and 18.9°), with a median of 6.7° and SD of 5.3°.
In this study the traditional use of face-bow devices showed inaccuracies in model mounting as well as in assignment of anatomic reference planes. Three-dimensional virtual computer-assisted planning seems to be more accurate than conventional methods.
Facial implants are readily used for aesthetic and reconstructive efforts in lieu of autogenous materials due to obvious benefits. Alloplastic facial augmentation is not without potential complications. This article discusses the major factors that contribute to complications of facial implant surgery, based on alloplast composition, surgical technique, and facial region. Also discussed are the most common complications as well as both their prevention and management.
Lengthening of the mandible by gradual distraction was performed on four young patients (average age 78 months). The amount of mandibular bone lengthening ranged from 18 to 24 mm; one patient with Nager's syndrome underwent bilateral mandibular expansion. Following the period of expansion, the patients were maintained in external fixation for an average of 9 weeks to allow ossification. The patients were followed for a minimum of 11 months to a maximum of 20 months with clinical and dental examinations as well as photographic and radiographic documentation. The technique holds promise for early reconstruction of craniofacial skeletal defects without the need for bone grafts, blood transfusion, or intermaxillary fixation.
After describing the salient skeletal and soft tissue abnormalities of oto-mandibular Dysostosis (o.-m.D.), the author's philosophy concerning the correction of the various forms and degrees of the skeletal deformities of o.-m.D. is described and illustrated. In particular his principles for the correction of the three-dimensional skeletal hypoplasia of the affected side are emphasized. Two forms of joint reconstruction are recommended, depending on the nature of the deformity. Not earlier than 3 months after the joint reconstruction the principal operation to correct the skeletal asymmetry is performed. This is the surgical rotation of the lower half of the facial skeleton caudally, anteriorly and towards the opposite side including the reconstruction of the hypoplastic or missing ramus utilizing rib grafts or/and iliac crest grafts. The required repositioning of the chin anteriorly and towards the normal side can be accomplished at the same time or at a later operation. The necessary soft tissue correction should be accomplished after a satisfactory skeletal symmetry has been obtained. Illustrated variations in the application of the basic principles of skeletal reconstruction are presented.
Bone deficiency in the craniofacial skeleton has posed a challenge to craniomaxillofacial surgeons for many decades. Sliding osteotomies and bone grafting have been traditional staples for correcting bone deficiency. In recent years, especially with the advent of newer devices, mechanically induced growth of bone and soft tissue has be-come a major tool in the correction of bony deficiency of the skull and face. In this article, the authors discuss the physiology and technique of distraction osteogenesis, or mechanically induced growth,for the correction of congenital and acquired facial deformities.
The purpose of this study is to assess the costs and benefits of computer-aided surgical simulation (CASS) and to compare it with the current surgical planning methods for complex cranio-maxillofacial (CMF) surgery.
The comparison of methods applies to all CMF surgeries where the patient's condition is severe enough to undergo a computed tomography scan and a stereolithographic model is necessary for the surgical planning process. The costs for each method can be divided into time and other costs. The time was estimated based on the authors' experience as well as on a survey of a small group of 6 experienced CMF surgeons in the United States. The other costs were estimated based on the authors' experience.
CASS has lower costs in terms of surgeon time, patient time, and material costs. Specifically, total surgeon hours spent in planning are 5.25 hours compared with 9.75 for current standard methods. Material and scanning costs are Dollars 1,900 for CASS compared with about Dollars 3,510 for standard methods. Patient time for planning is reduced from 4.75 hours to 2.25 hours with CASS. The reduction in both time and other costs remains when the fixed fee costs of CASS are added to the variable costs. Amortized across the 600 patients per year (1,800 for the assumed 3-year life of the training and software), this adds only a few dollars and a fraction of an hour per surgery. Even in the case of a small clinic when the cost is amortized for 6 patients per year (18 patients for the assumed 3-year life of the training and software), the per surgery costs (9.65 hours and Dollars 2,456) will still favor CASS.
Any great new design should consist of at least 2 of the 3 following features: faster, cheaper, and better outcome. This analysis demonstrates that CASS is faster and less costly than the current standard planning methods for complex CMF surgery. Previous studies have also shown that CASS results in better surgical outcomes. Thus, in all regards, CASS appears to be at least as good as the current methods of surgical planning.
Orthognathic surgery involves the surgical manipulation of the elements of the facial skeleton to restore normal anatomic and functional relationships in patients who have dentofacial skeletal anomalies. The elements of the facial skeleton can be repositioned, redefining the face through a variety of well-established osteotomies. Most maxillofacial deformities can be managed with the three basic osteotomies discussed in this article: the LeFort I type osteotomy, the bilateral sagittal split osteotomy of the mandibular ramus, and the horizontal osteotomy of the symphysis of the chin (osseous genioplasty).
Complications of fat grafting: how they occur and how to find, avoid, and treat them.
- Yoshimura K.
- Coleman S.R.