Nicolai Adolphs

RapidSplint: virtual splint generation for orthognathic surgery – results of a pilot series

Abstract 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.

Craniomaxillofacial surgery planning based on 3D models derived from Cone-Beam CT data

Abstract Introduction: Individual planning of complex maxillofacial corrections may require 3D models which can be manufactured based on DICOM datasets. The gold standard for image acquisition is still high-resolution multi-slice computed tomography (MSCT). However, appropriate datasets for model fabrication can be acquired by modern Cone-Beam CT (CBCT) devices that have been developed specifically for maxillofacial imaging. The clinical utility of individual models fabricated on the basis of CBCT datasets was assessed. Methods: In five patients affected by different deficiencies of the maxillofacial skeleton, preoperative imaging was performed with ILUMA CBCT. Segmentation of hard tissues was performed manually by thresholding. Corresponding STL datasets were created and exported to an industrial service provider (Alphaform, Munich, Germany) specializing in rapid prototyping, and 3D models were fabricated by the selective laser sintering (SLS) technique. For variance analysis, landmark measurements were performed on both virtual and 3D models. Subsequently, maxillofacial surgery was performed according to the model-based planning. Results: All CBCT-based DICOM datasets could be used for individual model fabrication. Detailed reproduction of individual anatomy was achieved and a topographic survey showed no relevant aberrance between the virtual and real models. The CBCT-based 3D models were therefore used for planning and transfer of different maxillofacial procedures. Conclusions: CBCT-based datasets can be used for the fabrication of surgical 3D models if the correct threshold is set. Preoperative workflow and patient comfort is improved in terms of the fast-track concept by using this “in-house” imaging technique.

Significance of distraction osteogenesis of the craniomaxillofacial skeleton – A clinical review after 10 years of experience with the technique

INTRODUCTION Distraction osteogenesis (DO) has been applied to the field of craniomaxillofacial surgery for more than two decades. Although relevant factors for successful distraction osteogenesis are well known there are ongoing controversies about indications and limitations of the method and there is still a lack of evidence based data. Since 2003 the principle of gradual lengthening has been applied to patients affected by different types of skeletal craniomaxillofacial deficiency within individualized treatment protocols at the Campus Virchow Klinikum - Charité Universitätsmedizin Berlin - by the same surgical team. The records of these patients were reviewed in order to assess the significance of the technique within the spectrum of a craniomaxillofacial department. During 10 years DO has been applied in 80 patients representing less than 1% of all patients that have been treated since 2003. Review of the protocols showed a heterogeneous group with a wide variance of parameters, the age ranging from 2½ to 51 years. Internal distraction devices were used in all cases and individually selected with respect to optimal stability during active distraction and consolidation phase. Although distraction related complications occurred the majority of procedures ended up with the favoured result and skeletal stability. However additional reconstructive surgery was required despite successful distraction in the majority of patients. Although DO has a low significance with respect to overall patient counts the method is a powerful tool within individual therapeutic concepts for the surgical correction of craniofacial anomalies that are characterized by skeletal deficiencies and should be seen as addendum to other surgical options. Predictable and stable results can be expected if the basic principles of the method are regarded.

Incidence and management of severe odontogenic infections—A retrospective analysis from 2004 to 2011

The management of odontogenic infections is a typical part of the spectrum of maxillofacial surgery. Normally these infections can be managed in a straight forward way however under certain conditions severe and complicated courses can arise which require interdisciplinary treatment including intensive care. A retrospective analysis of all patients affected by an odontogenic infection that received surgical therapy from 2004 to 2011 under stationary conditions was performed. Surgical treatment consisted in incision and drainage of the abscess supported by additional i.v. antibiotic medication in all patients. Detailed analysis of all patients that required postoperative intensive medical care was additionally performed with respect to special risk factors. During 8 years 814 patients affected by odontogenic infections received surgical treatment under stationary conditions representing 4% of all patients that have been treated during that period (n = 18981). In 14 patients (1.7%) intensive medical therapy after surgery was required, one lethal outcome was documented (0.12%). In all of these 14 patients a history of typical risk factors was present. According to these results two patients per week affected by an odontogenic infection required stationary surgical treatment, about two patients per year were likely to require additional intensive medical care. If well-known risk factors are present in patients affected by odontogenic infection appropriate interdisciplinary management should be considered as early as possible.

Antley–Bixler-Syndrome – Staged management of craniofacial malformations from birth to adolescence – A case report

In 1975 Antley and Bixler described an unusual syndromal disorder consisting of complex craniosynostosis with midfacial hypoplasia, dysplasia of ears and nose, radiohumeral synostosis, congenital fractures of the femur and upper airway impairment in a newborn. Additional urogenital and cardiac malformations can be associated however diagnosis is based on a characteristic craniofacial deformity in association with humeroradial synostosis. Complex disturbance of craniofacial growth due to premature synostoses of the cranial base and vault results in a characteristic phenotype. Steroidogenesis due to intrinsic or extrinsic disturbance by maternal fluconazole ingestion during early pregnancy may be impaired. The mode of inheritance is supposed to be autosomal recessive. Mutations in the fibroblast growth factor receptor 2 (FGFR2) as well as mutations in the cytochrome P450 oxidoreductase (OR) gene have been verified. Like in other craniofacial dysostosis syndromes malformation of neuro- and viscerocranium is complex and requires a staged age- and growth-related interdisciplinary management with respect to the individual situation. This case report of a female patient born in 1994 suffering from that rare syndrome describes the interdisciplinary long-term management in one craniofacial centre over 16 years from birth to adolescence.

Stable vertical distraction osteogenesis of highly atrophic mandibles after ablative tumour surgery of the oral cavity--a salvage pathway for mandibular reconstruction prior to oral rehabilitation with dental implants.

Mandibular reconstruction is still a challenge for surgeons. Distraction osteogenesis (DO) might contribute in certain instances to solve this problem. A principal advantage of DO is the expansion of the surrounding soft tissues that accompanies the bony regeneration. In addition there is no donor site morbidity when compared with reconstruction by autologous bone grafting. However its application may be limited by the thinness of the mandible and the attendant fracture risk. This article describes a technique that combines stable internal fixation with vertical distraction of the alveolar ridge in six patients with critical mandibular thickness after ablative surgery for cancer of the oral cavity. Prior to implant insertion for further prosthodontic restoration stable vertical mandibular distraction produced an additional 11-20mm. Improvement of the surrounding soft tissues, especially intraorally was achieved and dental implants were inserted after bony consolidation. This method can be a useful salvage technique for the augmentation of the atrophic mandible in patients who are not able or willing to undergo the risks and disadvantages of established methods such as free autologous bone transfer or microsurgical techniques.

Patient-Specific Implant in Prosthetic Craniofacial Reconstruction: First Report of a Novel Technique With Far-Reaching Perspective.

Background:Application of endosseous implants in prosthetic craniofacial reconstruction represents a secure and reliable method and is a well-established surgical procedure. In areas of low bone presentation, standardized plate-like titanium implants are available. For allowing a congruent fitting to the recipient site, these contemporary implants have to be manually adapted—implicating drawbacks in terms of time consumption, technical complexity, and insufficient functional outcome. Owing to these limitations, a custom-made patient-specific implant is introduced based on Digital Imaging and Communications in Medicine (DICOM) data and designed for optimal prosthetic reconstruction. Methods:For the first time, the application of a prefabricated patient-specific implant for retaining a craniofacial prosthesis is described. In a 64-year-old man with partial nasal defect standardized plate-like implants failed because of compromised bone quality due to Osler disease. To realize an implant-retained prosthetic reconstruction, a patient-specific implant was fabricated based on computer-aided design and computer-aided manufacturing (CAD/CAM) technology. This technique allows for considering the implants ideal geometry as well as its correct placement of the required magnetic abutments. Furthermore, the surface of the implant can be designed for optimal hygienic conditions. Results:The patient-specific implant was successfully inserted in a time effective operating procedure. Follow-up at 6 months showed an excellent functional and aesthetic outcome. Conclusions:Application of prefabricated patient-specific implants offers prospectively an ideal tool for retaining craniofacial prostheses and should be considered a viable option in standard cases, but obligatory in anatomically demanding defects.

Anaplastology in times of facial transplantation: Still a reasonable treatment option?

Optimum functional and aesthetic facial reconstruction is still a challenge in patients who suffer from inborn or acquired facial deformity. It is known that functional and aesthetic impairment can result in significant psychosocial strain, leading to the social isolation of patients who are affected by major facial deformities. Microvascular techniques and increasing experience in facial transplantation certainly contribute to better restorative outcomes. However, these technologies also have some drawbacks, limitations and unsolved problems. Extensive facial defects which include several aesthetic units and dentition can be restored by combining dental prostheses and anaplastology, thus providing an adequate functional and aesthetic outcome in selected patients without the drawbacks of major surgical procedures. Referring to some representative patient cases, it is shown how extreme facial disfigurement after oncological surgery can be palliated by combining intraoral dentures with extraoral facial prostheses using individualized treatment and without the need for major reconstructive surgery.

Frontofacial advancement by internal distraction devices. A technical modification for the management of craniofacial dysostosis in early childhood

Normal craniofacial growth is characterized by a different growth pattern of neuro- and viscerocranium. In craniofacial dysostosis (CFD) syndromes there is complex disturbance of this physiological growth pattern. Modern surgical management of CFD is staged with respect to the severity of the deformity, the age and the development of the patient. Early single stage management of anterior cranial vault deformity and midfacial retrusion in children affected by syndromic craniosynostosis is possible when anterior cranial vault remodelling is performed together with gradual Le Fort III midfacial advancement. One pair of internal distraction devices, placed in accordance with the midfacial growth vector after initial cranial vault remodelling, can be sufficient for this purpose. Technical aspects of this modified frontofacial advancement procedure are presented and discussed based on a case report with a postoperative follow up time of 50 months.

Necrotizing soft tissue infection of the scalp after fronto-facial advancement by internal distraction in a 7-year old girl with Gorlin–Chaudhry–Moss syndrome – A case report

In 1960, Gorlin, Chaudhry and Moss described a syndrome consisting of craniofacial dysostosis in association with hypertrichosis, cardiac, genital, dental and ocular anomalies. Diagnosis is based on typical clinical findings and cannot be performed by molecular genetic analysis until now. There is little in the clinical literature concerning this rare craniofacial syndrome. For functional and psychosocial reasons, surgical correction of the complex craniofacial malformation in a 7-year old Hungarian girl with Gorlin-Chaudhry-Moss syndrome was performed by fronto-facial advancement using internal distraction devices. Postoperatively necrotizing soft tissue infection of the scalp developed leading to termination of the distraction process ahead of schedule and requiring aggressive surgical management. Typical physiological and clinical characteristics were observed both during the initial craniofacial correction as well as during the management of the infectious complication suggesting that the linking of different conditions (surgical trauma plus the selection of toxic microorganisms) has caused tissue destruction rather than the syndromal disorder or the surgical technique of distraction osteogenesis. Although skeletal improvement was achieved residual damage from the infectious complication must be considered as severe.