Do miniscrews remain stationary under orthodontic forces?

Miniscrews have been used in recent years for anchorage in orthodontic treatment. However, it is not clear whether the miniscrews are absolutely stationary or move when force is applied. Sixteen adult patients with miniscrews (diameter = 2 mm, length = 17 mm) as the maxillary anchorage were included in this study. Miniscrews were inserted on the maxillary zygomatic buttress as a direct anchorage for en masse anterior retraction. Nickel-titanium closed-coil springs were placed for the retraction 2 weeks after insertion of the miniscrews. Cephalometric radiographs were taken immediately before force application (T1) and 9 months later (T2). The cephalometric tracings at T1 and T2 were superimposed for the overall best fit on the structures of the maxilla, cranial base, and cranial vault to determine any movement of the miniscrews. The miniscrews were also evaluated clinically for their mobility (0: no movement, 1: < or =0.5 mm, 2: 0.5-1.0 mm, 3: >1.0 mm). The mobility of all miniscrews was 0 at T1 and T2. On average, the miniscrews tipped forward significantly, by 0.4 mm at the screw head. The miniscrews were extruded and tipped forward (-1.0 to 1.5 mm) in 7 of the 16 patients. Miniscrews are a stable anchorage but do not remain absolutely stationary throughout orthodontic loading. They might move according to the orthodontic loading in some patients. To prevent miniscrews hitting any vital organs because of displacement, it is recommended that they be placed in a non-tooth-bearing area that has no foramen, major nerves, or blood vessel pathways, or in a tooth-bearing area allowing 2 mm of safety clearance between the miniscrew and dental root.

A modified pre-auricular approach to the temporomandibular joint and malar arch

In an attempt to improve visibility and safety in the surgical approach to the malar arch and jaw joint, anatomical dissections of 56 facial halves were undertaken. Observations are made on the relationship of the facial nerve bifurcation and its temporal branch to bony landmarks. Attention is drawn to the dangerous area of fusion of the superficial fascia, the superficial layer of temporal fascia and the periosteum of the malar arch. The safety of approaching the malar arch through the pocket formed by the splitting of the lower part of the temporal fascia is emphasised. Minor modifications to the established pre-auricular approach were made and applied successfully to six sides in five patients.

Outcome of aggressive removal of cavernous sinus meningiomas

Despite recent advances in surgery of the cavernous sinus, meningiomas in that area offer a formidable challenge. The rationale for aggressive surgical removal of cavernous sinus meningiomas is based on the presumption that the extent of removal is inversely related to the rate of recurrence. Over the past 10 years, 41 patients with histologically benign meningiomas involving the cavernous sinus underwent aggressive surgery. Total removal, as confirmed by intraoperative inspection and postoperative radiological studies, was achieved in 31 patients (76%). Twelve patients have been followed for more than 5 years; 10 underwent total tumor removal and only one of these experienced recurrence (5 years after surgery). The other two patients underwent subtotal removal and had symptomatic and radiological evidence of regrowth 3 and 4 years after surgery. Pre-existing cranial nerve deficits improved in only 14% of the patients, remained unchanged in 80%, and worsened permanently in 6%. Seven patients experienced a total of 10 new cranial nerve deficits, four of which involved the nerves subserving ocular motor function. Extraocular muscle function did not worsen in the 25 patients with a seeing eye ipsilateral to the tumor, and no instance of visual worsening occurred. Two patients died 4 months after surgery, one from severe delayed vasospasm and hypothalamic infarction and the other because of a myocardial infarction. Another patient died from a pulmonary embolus on the 9th postoperative day. There were three instances of cerebral ischemia; one was transient, lasting less than 24 hours, while two were related to injury of the middle cerebral artery and resulted in residual hemiplegia. Other complications included three cases of nonfatal pulmonary emboli, two cerebrospinal fluid leaks, and one instance each of exposure keratitis, acute hypothyroidism, and cerebral edema.

A combined retroauricular and preauricular transpetrosal-transtentorial approach to clivus meningiomas

A combined retroauricular and preauricular transpetrosal-transtentorial approach is described for the resection of meningiomas arising from the clivus. Via radical mastoidectomy the sigmoid sinus is exposed down to the jugular bulb, and via the transmastoideal-subtemporal approach the retroauricular petrosal bone, 1 cm in depth from the petrosal ridge, and the roof of the internal auditory meatus are removed, the middle ear and fallopian canal being left intact. Additionally, via a transzygomatic-subtemporal approach the preauricular petrosal bone is removed anteriorly up to the petrosal tip and laterally as far as the petrosal portion of the internal carotid artery, while the cochlea is preserved. By this means, the triangular portion of the posterior petrosal dura mater, delimited by the superior petrosal sinus, inferior petrosal sinus, and sigmoid sinus, is well exposed extradurally. By opening the subtemporal and posterior petrosal dura mater, in combination with a tentoriotomy, adequate exposure of the basilar artery, vertebral arteries, ventral and lateral portions of the brainstem, and cranial nerves is achieved with minimal retraction of the temporal lobe and cerebellum.

The orbitozygomatic infratemporal approach: a new surgical technique

Lesions in the parasellar region and the interpeduncular fossa, including medial-third sphenoid wing meningiomas, petroclival meningiomas, trigeminal neurinomas, and basilar tip aneurysms, are very difficult to approach for radical procedures. To minimize brain retraction and achieve excellent exposure in the shortest possible distance for safe manipulation within these regions, the authors have developed a new surgical technique, an orbitozygomatic infratemporal approach. Sixteen patients with parasellar tumors, nine patients with basilar tip aneurysms, and one patient with a P-1 distal aneurysm were operated on using this orbitozygomatic infratemporal approach, with excellent results. The operative technique and its results are detailed.

Distraction osteogenesis of the craniofacial skeleton

Distraction osteogenesis is becoming the treatment of choice for the surgical correction of hypoplasias of the craniofacial skeleton. Its principle is based on the studies of Ilizarov, who showed that osteogenesis can be induced if bone is expanded (distracted) along its long axis at the rate of 1 mm per day. This process induces new bone formation along the vector of pull without requiring the use of a bone graft. The technique also provides the added benefit of expanding the overlying soft tissues, which are frequently deficient in these patients. This article reviews the authors' 11-year clinical and research experience with mandibular distraction osteogenesis. It highlights the indications and contraindications of the technique and emphasizes the critical role that basic science research has played in its evolution.

Extradural temporopolar approach to lesions of the upper basilar artery and infrachiasmatic region

Surgical access to the parasellar, infrachiasmatic, and posterior clinoid regions has traditionally been accomplished through an intradural pterional or subtemporal approach. However, for large or complex lesions in these locations, such traditional trajectories may not afford sufficient exposure for complete obliteration of the pathological process. The authors describe an anterolateral transcavernous approach to this region that includes the following components: 1) extradural removal of the sphenoid wing and exposure of the superior orbital fissure and foramen rotundum; 2) removal of the anterior clinoid process via the anterolateral route; 3) decompression of the optic canal; 4) extradural retraction of the temporal tip; 5) transcavernous mobilization of the carotid artery and third cranial nerve; and 6) removal of the posterior clinoid process. This method results in enhanced exposure with minimal brain retraction and preservation of the temporal tip bridging veins. This approach has been used in 22 patients: 10 with basilar top aneurysms, eight with craniopharyngiomas, one with a tuberculum sellae meningioma, and two with trigeminal neuromas; the last patient had a carotid-cavernous fistula and a concomitant pituitary adenoma. Complete clip ligation was performed for all 10 basilar artery aneurysms, and gross total resection was achieved with preservation of the pituitary stalk in all tumor cases. Microscopic total resection was not possible in two cases of craniopharyngioma due to hypothalamic invasion. Two patients suffered transient postoperative hemiparesis, and one patient has persisting weakness; however, no patient followed for more than 6 months suffered any persistent cranial nerve morbidity. It is concluded that this procedure can serve as an alternative to either the transsylvian or subtemporal approaches when cranial base pathologies are large or complex.

A combined orbitozygomatic infratemporal epidural and subdural approach for lesions involving the entire cavernous sinus

The authors present four cases of vascular lesions and 10 cases of tumors involving the cavernous sinus. They were operated on via a combined orbitozygomatic infratemporal epidural and subdural approach. With this approach, multisided exposure of the cavernous sinus can be achieved via the shortest possible distance with minimal retraction of the neural structures in and around the cavernous sinus. In one patient the carotid artery had been occluded previously, but in the other 13 patients it was preserved. There was no mortality, and all patients except one returned to work within 6 months after surgery.

Zygoma fixture in the management of advanced atrophy of the maxilla: technique and long-term results

Despite refinements in surgical technique, including bone grafting and sophisticated prosthetic reconstructions, there are limitations to what can be achieved with bone-anchored fixed prostheses in patients with advanced atrophy of the maxillae. A new approach was suggested by a long-term study on onlay bone grafting and simultaneous placement of a fixture based on a new design: the zygoma fixture, and the aim of this study was to assess its potential. Twenty-eight consecutive patients with severely resorbed edentulous maxillae were included, 13 of whom had previously had multiple fixture surgery in the jawbone that had failed. A total of 52 zygoma fixtures and 106 conventional fixtures were installed. Bone grafting was deemed necessary in 17 patients. All patients have been followed for at least five years, and nine for up to 10 years. All patients were followed up with clinical and radiographic examinations, and in some cases rhinoscopy and sinoscopy as well. Three zygoma fixtures failed; two at the time of connection of the abutment and the third after six years. Of the conventional fixtures placed at the time of the zygoma fixture, 29 (27%) were lost. The overall prosthetic rehabilitation rate was 96% after at least five years of function. There were no signs of inflammatory reaction in the surrounding antral mucosa. Four patients with recurrent sinusitis recovered after inferior meatal antrostomy. To conclude, the zygoma fixture seems to be a valuable addition to our repertoire in the management of the compromised maxilla.

Trigeminal neurinomas extending into multiple fossae: surgical methods and review of the literature

OBJECT

Since 1974, 27 patients with trigeminal neurinomas (TNs) have been treated at Keio University Hospital and ancillary institutes. In the present study the clinical features and developmental patterns of these 27 cases are analyzed, and the clinical features of 402 cases reported in the literature are reviewed. Based on the analysis of the developmental patterns of the TNs, the surgical strategy for a one-stage removal of TNs involving multiple fossae is described.

METHODS

Trigeminal neurinomas are classified into six types according to tumor location. Types M, P, and E are tumors involving a single compartment, that is, the middle fossa, posterior fossa, or extracranial space, respectively. Types MP (middle and posterior fossae), ME (middle fossa and extracranial space), or MPE (middle and posterior fossae and extracranial space) are tumors involving multiple compartments. Advances in neuroimaging technologies, such as magnetic resonance imaging, have revealed a high incidence of TNs extending into multiple fossae, namely 36.2% in cases reported since 1983 and 59% in the authors' series. All but one of the most recent 19 patients in this series underwent skull base surgery, whereas the remaining nine patients were surgically treated via the conventional subdural approach. The rate of total tumor removal and the clinical outcome were significantly better in those patients treated by skull base surgery than those treated by conventional surgery.

CONCLUSIONS

The TNs extending into multiple fossae can be totally removed using the following single-stage surgical techniques: Type MP by the anterior transpetrosal approach; Type ME by the zygomatic or orbitozygomatic infratemporal approach; and Type MPE by the zygomatic transpetrosal approach. In 12 of 13 cases involving multiple fossae in this series, total tumor removal was achieved using single-stage skull base surgery.

Orbitozygomatic craniotomy. Technical note

The orbitozygomatic approach provides wide, multidirectional access to the anterior and middle cranial fossae, as well as to the upper third of the posterior fossa and clivus. The authors describe technical details of the surgical approach as it has evolved over 3.5 years of experience in 83 consecutive cases. This modified technique eliminates the need for bone reconstruction of the orbital walls to prevent enophthalmos and minimizes the risk of injury to the frontal branch of the facial nerve. At a follow-up evaluation after a period averaging 14 months, all patients were pleased with the cosmetic results of this approach.

The infratemporal fossa approach for nasopharyngeal tumors

The technique and results of the infratemporal fossa surgical removal of carcinomas and juvenile angiofibromas of the nasopharynx are presented. Effective palliative removal of T4 and radical removal of T1 and T2 nasopharyngeal carcinomas was achieved. A classification of juvenile nasopharyngeal angiofibroma is presented. The infratemporal fossa approach allows radical removal of type III tumors and subtotal removal of type IV tumors. If residual tumor has to be left back in the cavernous sinus, irradiation is used to stop further growth of the tumor. If radiotherapy fails the neurosurgical removal of the intracranial portion of the tumor is indicated.

Retrospective Study of 1251 Maxillofacial Fractures in Children and Adolescents

BACKGROUND

Fractures of the facial skeleton are relatively uncommon in children and adolescents, and only a few reports review a significant number of patients. The authors performed a retrospective study to analyze the different characteristics of such fractures in the pediatric population of Portugal.

METHODS

The authors reviewed the clinical records of a series of 912 patients 18 years of age or younger with facial fractures treated by the Departments of Plastic, Reconstructive, and Aesthetic Surgery and of Maxillofacial Surgery, São João Hospital, in Porto, Portugal, between the years 1993 and 2002. The following parameters were evaluated: age; sex; cause of accident; hour, day, and month of hospital admission; location and type of fractures; presence and location of associated injuries; treatment methods; length of in-hospital stay; and complications.

RESULTS

A total of 1251 fractures were treated. The ratio of boys to girls was 3.1:1. Patients between 16 and 18 years old were the major group (47.8 percent). Motor vehicle accident was the most common cause of injury (53.3 percent of patients). Mandibular fracture was the most common type of fracture (48.8 percent). Associated injuries occurred in 558 patients (64.5 percent).

CONCLUSIONS

Pediatric facial fractures are usually associated with severe trauma. The number of fractures caused by automobile accidents has decreased (p < 0.05). The incidence of this type of fracture is high in Portugal.

Zygomatic approach to skull-base lesions

A modification of the preauricular skull-base approach is described. After sectioning and downward displacement of the zygomatic arch, the coronoid process of the mandible is dissected and sectioned at its base. The temporal muscle, with its coronoid insertion, is then retracted upward. This approach provides direct and unobstructed access to the temporal and infratemporal fossae. Adequate vascularity of the temporal muscle is maintained. The exposure encompasses the internal carotid artery in the neck for vascular control. Extensive reconstruction is eliminated. The described technique was used in seven patients with lesions of the skull base. There was no operative mortality, and morbidity consisted of temporary restriction of mandibular opening in two patients.

Survival and Complications of Zygomatic Implants: An Updated Systematic Review

PURPOSE

To assess the survival rate of zygomatic implants (ZIs) and the prevalence of complications based on previously published studies.

MATERIALS AND METHODS

An electronic search of 3 databases was performed in December 2015 and was supplemented by manual searching. Clinical series of ZIs were included. Interval survival rate and cumulative survival rate (CSR) were calculated. The untransformed proportion of complications (sinusitis, soft tissue infection, paresthesia, oroantral fistulas) was calculated by considering the prevalence reported in the studies.

RESULTS

Sixty-eight studies were included, comprising 4,556 ZIs in 2,161 patients with 103 failures. The 12-year CSR was 95.21%. Most failures were detected within the 6-month postsurgical period. Studies (n = 26) that exclusively evaluated immediate loading showed a statistically lower ZI failure rate than studies (n = 34) evaluating delayed loading protocols (P = .003). Studies (n = 5) evaluating ZIs for the rehabilitation of patients after maxillary resections presented lower survival rates. The probability of presenting postoperative complications with ZIs was as follows: sinusitis, 2.4% (95% confidence interval [CI], 1.8-3.0); soft tissue infection, 2.0% (95% CI, 1.2-2.8); paresthesia, 1.0% (95% CI, 0.5-1.4); and oroantral fistulas, 0.4% (95% CI, 0.1-0.6). However, these numbers might be underestimated, because many studies failed to mention the prevalence of these complications.

CONCLUSION

ZIs present a high 12-year CSR, with most failures occurring at the early stages postoperatively. The main observed complication related to ZIs was sinusitis, which can appear several years after ZI installation surgery.

New approach to the nasopharynx: the maxillary swing approach

A new approach to expose the nasopharynx and the paranasopharyngeal space is described. The maxilla, severed from its bony connections, is swung laterally to provide exposure of the nasopharynx. Tumors in the nasopharynx and the paranasopharyngeal space can be adequately resected and tubings for afterloading brachytherapy can be positioned accurately during surgery. The blood supply of the maxilla is from the attached cheek flap and masseter muscle. Three illustrative cases are presented. The wounds in all of them healed primarily with minimal morbidity. The only disadvantage is the development of mild trismus, which responded to conservative treatment.

Image-based planning and clinical validation of zygoma and pterygoid implant placement in patients with severe bone atrophy using customized drill guides. Preliminary results from a prospective clinical follow-up study

The zygoma implant has been designed for those situations where there is insufficient bone in the upper jaw, which would otherwise require onlay or inlay (sinus) bonegrafts. The aim of the study was to present and validate a planning system for implant insertion based on preoperative CT imaging. It allows the surgeon to determine the desired position of different kinds of implants. Finally a customized drill guide is produced by stereolithography. In this study, zygoma, pterygoid and regular platform implants were used. The treatment protocol is validated through 12 case studies, selected at random from the total patient group (n=29 patients). From postoperative images, the exact implant location is determined and the deviation of axes between planned and inserted implants is calculated. In this in vivo study, displacements, varying according to the type of implant and the location of the implants, were observed. From a clinical standpoint, most of the inserted implants were judged to be adequately sited. A prospective clinical follow-up study was performed on all 29 patients. Although all patients presented with severe maxillary atrophy, excellent cumulative survival rates (92%) for the zygoma implants and 93% for regular platform implants have been obtained.

The importance of the zygomatic arch in complex midfacial fracture repair and correction of posttraumatic orbitozygomatic deformities

Collapse of the zygomatic arch following trauma results in inadequate anteroposterior projection of the zygomatic body and an increase in facial width. Accurate assessment of the position of the zygomatic arch in relation to the cranial base posteriorly and the midface anteriorly is the key to the acute repair of complex midfacial fractures and the secondary reconstruction of posttraumatic deformities of the orbitozygomaticomaxillary complex. Loss of projection of the zygomatic arch may occur with injuries confined to the orbitozygomaticomaxillary region or in association with complex midfacial fractures. A safe anatomic approach to the zygomatic arch allows exact anatomic restoration of the zygomatic arch using miniplates and screws and results in the reconstruction of an outer facial frame with a correct anteroposterior projection and facial width. The zygomatic arch injury is diagnosed using axial CT scanning. Three-hundred and seventeen arches have been exposed through a coronal incision following acute trauma and 47 arches have been exposed in patients requiring late correction of a posttraumatic orbitozygomaticomaxillary deformity. Permanent palsy to the frontal branch of the facial nerve has occurred in one patient following the exact definition of the anatomy of this region.

Correction of post-traumatic orbital deformities: operative techniques and review of 26 patients

The skeletal reconstruction of post-traumatic orbital deformities includes the zygomatic complex, the nasoethmoid area and the internal orbit. Repositioning of the malpositioned zygoma is the key element and the first step. Due to remodelling processes, most of the landmarks for proper positioning are lost, leaving the lateral orbital wall as the only reliable landmark in secondary revisions. The details of the skeletal reconstruction are discussed. Between January 1988 and December 1992, 31 patients with major post-traumatic orbital deformities have been operated on, of which 26 could be followed for a minimum of 6 months. A total of 61 operative procedures using craniofacial techniques have been performed. Complications occurred in 5 (15%) of the 26 patients, the most severe being visual loss caused by a displaced bone graft. The most frequent deformity was enophthalmos. Most patients presented with more than one deformity. The aesthetic results were rated as 'good' in 12, 'satisfactory' in 8 and 'unsatisfactory' in 6 patients. Of the patients suffering from double vision, 55% were improved after orbital reconstruction. Craniofacial techniques allow radical correction of post-traumatic skeletal deformities. The functional and aesthetic results, however, are limited by the soft tissues.

Accuracy of drilling guides for transfer from three-dimensional CT-based planning to placement of zygoma implants in human cadavers

The accuracy of surgical drilling guides was assessed for placement of zygoma implants. Six zygoma fixtures of length 45 mm (Nobel Biocare, Göteborg, Sweden) were placed in three formalin-fixed human cadavers using surgical drilling guides. The fabrication of these custom-made drilling guides was based on three-dimensional computerized tomography (3D-CT) data for the maxillary-zygomatic complex. The installation of the implants was simulated preoperatively using an adopted 3D-CT planning system. In addition, anatomical measurements of the zygomatic bone were performed on the 3D images. The preoperative CT images were then matched with postoperative ones in order to assess the deviation between the planned and installed implants. The angle between the planned and actually placed implants was < 3 degrees in four out of six cases. The largest deviation found at the exit point of one of the six implants was 2.7 mm. The present study showed that the use of surgical drilling guides should be encouraged for zygoma implant placement because of the lengths of the implants involved and the anatomical intricacies of the region.

Clinical outcome of 103 consecutive zygomatic implants: a 6-48 months follow-up study

The purpose of this study was to evaluate retrospectively, after a period of 6-48 months follow-up of prosthetic loading, the survival rate of 103 zygomatic implants inserted in 55 totally edentulous severely resorbed upper jaws. Fifty-five consecutive patients, 41 females and 14 males, with severe maxillary bone resorption were rehabilitated by means of a fixed prosthesis supported by either 1 or 2 zygomatic implants, and 2-6 maxillary implants. This retrospective study calculated the success and survival rates at both the prosthetic and implant levels. Out of 55 prostheses, 52 were screwed on top of the implants, while 3 were modified due to loss of standard additional implants and transformed in semimovable prosthesis. Although osseointegration in the zygomatic region is difficult to evaluate, no zygomatic implant was considered fibrously encapsulated and they are still in function. This study confirms that zygoma bone can offer a predictable anchorage and support function for a fixed prosthesis in severely resorbed maxillae.

Remote implant anchorage for the rehabilitation of maxillary defects

The rehabilitation of maxillary defects is a significant challenge in terms of creating retention and preserving existing dentition in an environment of expanded functional stress. The advent of osseointegration has enhanced the dental practitioner's capabilities in this regard with a remarkably improved potential for increasing prosthesis stability and preserving tissue. For patients with extensive prosthetic cantilevers, however, the opportunity for implant placement in defect areas is compromised unless remote bone sites are considered. Implants in the defect buttress zone through the maxillary sinus in non-defect sites (zygoma implants) can be valuable in providing a level of functional rehabilitation previously unattainable.

Maxillary-midface distraction in children with cleft lip and palate: a preliminary report

A miniature system of distraction devices has been employed for maxillary-midface advancement in two children with cleft lip and palate, class III malocclusion, and associated midfacial hypoplasia. The devices are made with commercially available palatal expansion screws linked to rigid fixation plates. A midfacial osteotomy is used, and distraction is begun on the third postoperative day. In the first child, a 7-year-old boy, the midface was distracted 11 mm sagittally and 4 mm inferiorly. In the second patient, a 4 1/2-year-old girl with unilateral cleft lip and palate and midfacial retrusion, an 11-mm distraction was carried out in the vertical and sagittal direction. There were no complications, and none of the devices failed. Maxillary-midfacial distraction osteogenesis to correct severe maxillary-midfacial hypoplasia in children with clefts and other craniofacial disorders permits early intervention with potentially less invasive techniques than are currently available.

Verification of clinical precision after computer-aided reconstruction in craniomaxillofacial surgery

OBJECTIVE

Computer-aided surgery (CAS) has proved to be useful in reconstructive craniomaxillofacial surgery. Preoperative creation of virtual models by segmentation of the computerized tomography (CT) dataset and mirroring of the unaffected side allows for precise planning of complex reconstructive procedures. The aim of this study was to evaluate the accuracy of the preoperative planning and the postoperative result regarding the skeletal reconstruction.

STUDY DESIGN

In a first step, the symmetry of unaffected human skulls and faces were evaluated by 20 midface CT data of skulls and 20 surface-scan data of healthy individuals. By mirroring and adjusting the original and mirrored datasets using a 3-dimensional modeling software, an automatic measurement procedure could evaluate the mean and the maximal modulus of the distances between both datasets. In a second step, 18 consecutive cases were selected which had been treated with CAS support. Group 1 consisted of orbital floor and/or medial wall fractures (n = 12), group 2 consisted of zygomatic bone fractures (n = 4), and group 3 included 2 patients who were treated by secondary orbital reconstruction including reosteotomy of the zygomatic bone (n = 2). To verify the surgical result, the preoperative CT dataset including the virtual planning and the postoperative CT dataset were compared by using image fusion. Additionally, postoperative surface scans and the clinical symptoms of the patients were evaluated.

RESULTS

No differences between the skull and face symmetry were found. Mean values for distances considering the skull symmetry were 0.83 mm for male and 0.71 mm for female and for the face symmetry 0.65 mm for male and 0.76 mm for female. Comparing the preoperative planning with the postoperative outcome, a mean accuracy of 1.49-4.12 mm with maximum modulus of 2.49-6.00 mm was achieved. Orbital true-to-original reconstructions and the secondary reconstructions were more precise than the reposition of the zygomatic bones. The postoperative acquired surface scans resulted in mean distances from 0.89 to 1.784 mm. Despite these deviations, all patients demonstrated satisfying clinical outcome.

CONCLUSION

The natural asymmetry in humans influences the accuracy of preoperative planning procedure, when the mirroring tool is used. The accuracy transforming the preoperative planning to the surgical reconstruction using CAS depends on location, surgical approach, and matter of reconstruction.