Clinical outcome after orbital floor fracture reduction with special regard to patient's satisfaction.

PURPOSE: Primary reconstruction via transconjunctival approach is a standardized treatment option for orbital floor fractures. The aim of this study was to compare the findings of specific ophthalmologic assessment with the patient's complaints after fracture reduction. METHODS: A retrospective medical chart analysis was performed on patients who had undergone transconjunctival orbital floor fracture reduction for fracture therapy with resorbable foil (ethisorb sheet or polydioxanone foil). A follow-up assessment including ophthalmological evaluation regarding visual acuity (eye chart projector), binocular visual field screening (Bagolini striated glasses test) and diplopia (cover test, Hess screen test) was conducted. Additionally, a questionnaire was performed to assess patients' satisfaction. RESULTS: A total of 53 patients with a mean follow-up of 23 months (ranging from 11 to 72) after surgical therapy were included. Diplopia was present preoperatively in 23 (43.4%) and reduced in follow-up examination (n = 12, 22.6%). Limitations in ocular motility reduced from 37.7% to 7.5%. The questionnaire about the patient's satisfaction revealed excellent outcomes in relation to the functional and esthetical parameters. CONCLUSION: Transconjunctival approach is a safe approach for orbital fracture therapy. Postoperative diplopia is nearly never perceptible for the individual and differs to pathologic findings in the ophthalmic assessment.

[Frequency and management of complex facial fractures-an oral and maxillofacial surgical assessment]. / Häufigkeit und Management von Gesichtsschädelfrakturen ­ eine MKG-chirurgische Einschätzung.

INTRODUCTION: The treatment of facial fractures is an integral part of the oral and maxillofacial surgical treatment spectrum. In the case of complex fractures that involve multiple levels of the facial skeleton associated with severe concomitant injuries, an individual and interdisciplinary treatment approach is needed, which requires the infrastructure of a national trauma center. OBJECTIVE: The aim of this study was to analyze the incidence and management of patients with complex facial fractures and considering the concomitant injury pattern. MATERIAL AND METHODS: A retrospective analysis of patients with complex facial fractures during the years 2009-2015 admitted to the emergency surgical department of a national trauma center was carried out. The identification of appropriate patient cases was based on the International Statistical Classification of Diseases and Related Health Problems (ICD) coding of electronic patient data. Only patients with at least a combination of mandibular and midfacial fractures (2-level fractures) were considered. Patients with mainly dentoalveolar fractures and simple nasal bone fractures were not included. The evaluation of the electronic medical records included the etiology, fracture pattern, associated severe injuries on the basis of the injury severity score (ISS), treatment regimen as well as the length of the hospital stay. RESULTS: In the 7­year study period, 3382 patients were identified with facial fractures. Of these, 128 patients (3.78%) presented with a complex fracture pattern with a combination of mandibular fractures and fractures of the midface. The majority of these patients (n = 92) had less severe concomitant injuries (ISS ≤ 16), while 36 patients showed severe concomitant injuries (ISS > 16). The incidence of a 3-level fracture involving the mandible, midface and anterior skull base was only 0.47% and could be detected in 16 patients, of which 10 were classified as polytrauma (ISS > 16). CONCLUSION: The incidence of complex fractures of the facial skeleton was comparatively low with almost 4%. More than one in four patients with complex injury patterns of the facial skeleton exhibited severe concomitant life-threatening injuries, necessitating an interdisciplinary management with the specialized infrastructure of a nationwide trauma center.

Following in the footsteps of Hippocrates-interrelation between the incidence of odontogenic abscess and meteorological parameters.

OBJECTIVES: Although many physicians in daily practice assume a connection between odontogenic infections and meteorological parameters, this has not yet been scientifically proven. Therefore, the aim of the present study was to evaluate the incidence of odontogenic abscess (OA) in relation to outdoor temperature and atmospheric pressure. PATIENTS AND METHODS: An analysis of patients with an odontogenic abscess who presented at the emergency department within a period of 24 months was performed. Only patients who had not received surgical or antibiotic treatment prior to presentation and who lived in Berlin/Brandenburg were included. The OA incidence was correlated with the mean/maximum outdoor temperature and atmospheric pressure starting from 14 days before presentation. The statistical analysis was carried out using Poisson regression models with OA incidence as dependent and meteorological parameters as independent variables. RESULTS: A total of 535 patients (mean age 39.4 years; range 1 to 95 years) with 538 cases were included. Of these, 227 were hospitalized. The most frequent diagnosis was a canine fossa abscess. A significant association between mean (p = 0.0153) and maximum temperature (p = 0.008) on the day of the presentation and abscess incidence was observed. Furthermore, a significant correlation between OA incidence and maximum temperature 2 days before presentation was found (p = 0.034). The deviation of the mean temperature on the day of the presentation from the monthly mean temperature had a significant influence (p = 0.021) on the incidence of OA. In contrast to temperature, atmospheric pressure had no significant influence on the incidence of OA. CONCLUSION: This study supports a relationship between the incidence of odontogenic abscess and outdoor temperature, but not atmospheric pressure. A significantly higher frequency of patients with an OA presented at our emergency department on days with (comparably) low and high outdoor temperatures. Furthermore, a significant correlation between incidence and maximum temperature 2 days before presentation was found. CLINICAL RELEVANCE: The treatment of odontogenic infections has become a significant economic burden to public health care facilities. The results of this study may help to adapt the numbers of doctors/dentists on duty in relation to different weather conditions. In any case, it is an impetus to think outside the box.

Sublingual cysts of different entities in an infant - A case report and literature review.

BACKGROUND: Congenital cysts and fistulas of the neck are common in children, often located in the head and neck area. Belonging to the group of tumor-like conditions, dermoid and epidermoid cysts are dysontogenetic lesions with seldom multiple co-occurrences in infants. CASE REPORT: We report on a nine-month-old female with a persisting congenital fistula of the tongue. The patient was admitted with acute poor feeding and hypersalivation, which started within the last 24 h. Magnetic resonance imaging detected a fistula of the tongue connected to sublingual cystic lesions. Intraoral surgical removal of three cystic lesions and the fistula was performed under general anesthesia. Histopathological analysis confirmed the coexistence of an epidermoid cyst and two dermoid cysts. CONCLUSION: Sudden feeding difficulties in combination with dysphagia and tongue displacement in pediatric patients pose an emergency situation that requires prompt diagnostic clarification. A persisting congenital fistula of the tongue is a clear indication of dysontogenetic lesions, including malformations, tumors, and tumor-like lesions. Congenital sublingual cysts are rare in infants, but can be life threatening when present. Surgical excision with histopathological analysis is essential to exclude any form of malignancy and malignant transformation.

Penetrating Foreign Bodies in Head and Neck Trauma: A Surgical Challenge.

Penetrating foreign bodies of different origins in the head and neck are rare and potentially dangerous injuries, which might pose problems for their detection, primary care, and final treatment. Depending on the severity of the underlying trauma, some injuries present a higher risk for the presence of foreign bodies. Minor wounds, including common lacerations, are likely to be contaminated with loose gravel debris or dental fragments, and need to be distinguished from severe wounds caused by impalement, shootings, stabbings, and explosions. Blast injuries resulting from terror attacks are challenging recent therapeutic concepts. Even though these injury patterns are uncommon, they carry the risk of impacted objects with dramatic consequences. Despite improving medical imaging techniques, detection remains a challenge as it is dependent on the material of the foreign body, the affected anatomical site, and the injury severity. Therefore, a detailed history of the circumstances leading to trauma is essential when foreign objects are not visible during clinical examination. Precise detection of the foreign body, its anatomical position, and the affected surrounding structures are vital, especially for impalement injuries of the head and neck area. Therefore, an interdisciplinary planning approach is essential prior to removal of the foreign object. Finally, tension-free anatomical adaptation of the corresponding structures is crucial for maintaining and restoring aesthetic and function. Here, we give an overview of the diagnosis and treatment of cases of foreign body injuries encountered in our department.

Distraction Osteogenesis After Stem Cell Transplantation: A Pioneer Approach.

Allogeneic hematopoietic stem cell transplantation (HSCT) is an established therapy and is without alternative for certain groups of patients. Successful HSCT induces both long-lasting remission and tolerance without the need for further immunosuppression. In this case, cellular repair and regenerative processes work in a physiologic manner allowing elective surgical procedures, such as the interdisciplinary correction of dentofacial anomalies. Here, we report the successful management of transverse maxillary deficiency by transpalatal distraction and subsequent orthodontic treatment in a 12-year-old boy who underwent HSCT for high-risk acute lymphoblastic leukemia at 5 years of age.

De Novo Mutations in SLC25A24 Cause a Craniosynostosis Syndrome with Hypertrichosis, Progeroid Appearance, and Mitochondrial Dysfunction.

Gorlin-Chaudhry-Moss syndrome (GCMS) is a dysmorphic syndrome characterized by coronal craniosynostosis and severe midface hypoplasia, body and facial hypertrichosis, microphthalmia, short stature, and short distal phalanges. Variable lipoatrophy and cutis laxa are the basis for a progeroid appearance. Using exome and genome sequencing, we identified the recurrent de novo mutations c.650G>A (p.Arg217His) and c.649C>T (p.Arg217Cys) in SLC25A24 in five unrelated girls diagnosed with GCMS. Two of the girls had pronounced neonatal progeroid features and were initially diagnosed with Wiedemann-Rautenstrauch syndrome. SLC25A24 encodes a mitochondrial inner membrane ATP-Mg/Pi carrier. In fibroblasts from affected individuals, the mutated SLC25A24 showed normal stability. In contrast to control cells, the probands' cells showed mitochondrial swelling, which was exacerbated upon treatment with hydrogen peroxide (H2O2). The same effect was observed after overexpression of the mutant cDNA. Under normal culture conditions, the mitochondrial membrane potential of the probands' fibroblasts was intact, whereas ATP content in the mitochondrial matrix was lower than that in control cells. However, upon H2O2 exposure, the membrane potential was significantly elevated in cells harboring the mutated SLC25A24. No reduction of mitochondrial DNA copy number was observed. These findings demonstrate that mitochondrial dysfunction with increased sensitivity to oxidative stress is due to the SLC25A24 mutations. Our results suggest that the SLC25A24 mutations induce a gain of pathological function and link mitochondrial ATP-Mg/Pi transport to the development of skeletal and connective tissue.

Mutation c.943G>T (p.Ala315Ser) in FGFR2 Causing a Mild Phenotype of Crouzon Craniofacial Dysostosis in a Three-Generation Family.

Crouzon syndrome craniofacial dysostosis type I [OMIM 123500] is caused by mutations in the gene encoding fibroblast growth factor receptor-2 (FGFR2). An overlapping phenotype with Muenke and Crouzon syndrome with acanthosis nigricans (FGFR3 mutations) is known. The clinical diagnosis can be corroborated by molecular studies in about 80-90% of the cases. No clear genotype/phenotype correlation has been identified yet. Here, we describe a second family with a mild phenotype in which the FGFR2 mutation c.943G>T leading to the amino acid substitution p.Ala315Ser was detected. Five affected family members showed craniofacial dysostosis without overt craniosynostosis. They all had midface hypoplasia. Crouzonoid appearance with mild protrusion of bulbi was only apparent in our index patient as well as obstructive sleep apnea episodes leading to reduced oxygen saturation; therefore, surgical intervention was suggested. One other affected family member additionally had iris coloboma.

The "tight orbit": Incidence and management of the orbital compartment syndrome.

PURPOSE: The orbital compartment syndrome (OCS) constitutes a severe emergency, requiring immediate clinical diagnosis and surgical decompression. The key symptom is progressive visual impairment caused by an increase in intraorbital pressure, impairing the perfusion of relevant neurovascular and neurosensory structures. Intraorbital bleeding due to trauma and surgical intervention is known to be the main etiological factor. MATERIAL AND METHODS: A retrospective analysis of all patients affected by an OCS between January 1, 2012, and May 31, 2015, was performed. Patients' records were reviewed with regard to etiology, initial ophthalmologic status, fracture pattern, concomitant medication, surgical management, and postoperative outcome. The incidence of OCS was calculated based on the total number of craniomaxillofacial (CMF) emergencies. RESULTS: Within 3.5 years, a total of 18,093 CMF emergencies were registered. In 16 patients, an OCS was documented, corresponding to an incidence of 0.088%. The mean patient age was 67.31 ± 23.86 years, ranging from 22 to 102 years. The etiology varied, but trauma with subsequent intraorbital bleeding was the main cause. The use of anticoagulative medication was documented in 50% of the cases. In 14 patients, immediate surgical orbital decompression was performed: in 10 patients, vision could be preserved; in three patients, blindness resulted; and one patient was lost to follow-up. Two patients were managed without surgery. CONCLUSION: With regard to the total number of CMF emergencies, OCS is a rare condition. Early clinical diagnosis and surgical decompression are required to prevent permanent vision impairment. Anticoagulative medication must be considered as a predisposing factor for an orbital compartment syndrome in patients affected by periorbital trauma.

Contemporary Correction of Dentofacial Anomalies: A Clinical Assessment.

Contemporary computer-assisted technologies can support the surgical team in the treatment of patients affected by dentofacial deformities. Based on own experiences of 350 patients that received orthognathic surgery by the same team from 2007 to 2015, this clinical review is intended to give an overview of the results and risks related to the surgical correction of dentofacial anomalies. Different clinical and technological innovations that can contribute to improve the planning and transfer of corrective dentofacial surgery are discussed as well. However, despite the presence of modern technologies, a patient-specific approach and solid craftsmanship remain the key factors in this elective surgery.

Role of distraction osteogenesis in craniomaxillofacial surgery.

In the field of orthopedic surgery, distraction osteogenesis (DO) is well known for limb lengthening procedures or secondary corrective surgery in the fracture treatment of the extremities. The principle of gradual expansion of bone and surrounding soft tissues as originally described by G.A. Ilizarov is also applicable to the craniofacial skeleton when growth deficiency is present, and the patients affected by craniofacial or dentofacial anomalies may require distraction procedures. The surgical management is comparable. After osteotomy and the mounting of a specific craniomaxillofacial distraction device, active distraction is started after a latency phase of several days, with a distraction rate of up to 1 mm/day until the desired amount of distraction has been achieved. Subsequently, distractors are locked to provide appropriate stability within the distraction zone for callus mineralization during the consolidation phase of 3-6 months, which is followed by a further remodeling of the bony regenerate. After 14 years of clinical application, the role and significance of craniomaxillofacial DO are discussed after reviewing the files of all patients who were treated by craniomaxillofacial distraction procedures.

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 implant's 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.

Transpalatal distraction for the management of maxillary constriction in pediatric patients.

CONTEXT: The management of severe maxillary constriction can be challenging. For that purpose surgically assisted maxillary expansion by transpalatal distraction (TPD) can typically be recommended after skeletal maturity. However in selected cases bone borne transpalatal distraction devices can contribute to improve maxillary constriction considerably earlier already during mixed dentition. AIMS: To assess the possibility of bone borne transpalatal distraction in pediatric patients. SETTINGS AND DESIGN: Clinical paper. MATERIALS AND METHODS: Since 2010 TPD has been applied to six pediatric patients during mixed dentition when severe maxillary constriction was present and conventional orthodontic widening has already failed. Individually selected devices (Surgitec, Belgium) were inserted in general anaesthesia and distraction was performed according to well known parameters. RESULTS: Maxillary constriction could be improved in all six patients without any drawbacks by bone borne devices during mixed dentition. Skeletal conditions were obviously improved for subsequent orthodontic or orthognathic therapy without functional impairment. Follow-up is up to 36 months after device removal. CONCLUSIONS: Transpalatal Distraction is recommendable in selected pediatric patients if massive growth disturbance is present or has to be expected. TPD allows for individually adapted maxillary expansion by selection and positioning of appropriate devices in combination with intraoperative testing of maxillary movements and controlled bone removal.

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.

Magnetic resonance imaging induced acute midfacial pain - incidental finding of a dislocated dental bur.

PURPOSE: To describe the management of a patient with an initially unnoticed dislocated dental bur in the maxillary sinus that became symptomatic during a magnetic resonance imaging (MRI) scan. MATERIALS AND METHODS: A MRI scan provoked strong midfacial pain in a 31-year-old male patient, who exhibited ambiguous neurologic impairment consistent with multiple sclerosis. Conventional radiography revealed an opaque foreign body in close proximity to the orbital floor that most likely caused the painful symptoms during the MRI. RESULTS: After additional X-ray computed tomography (X-ray CT) scans were performed, a metal dental bur was removed by a combined transconjunctival and transnasal approach under perioperative antibiotic treatment. CONCLUSION: The disappearance of instruments during surgical procedures requires diligent investigation and immediate retrieval.

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.

Transpalatal distraction--state of the art for the individual management of transverse maxillary deficiency--a review of 50 consecutive cases.

Transpalatal distraction has been established as a technique for surgical assisted rapid palatal/maxillary expansion (SARPE/SARME) in order to correct transverse maxillary deficiency. From 2007 until 2013 bone borne transpalatal distraction devices have been inserted in 50 patients affected by transverse maxillary deficiency and transpalatal distraction has been performed by the same surgical team. Patient records were retrospectively evaluated after ending of the active distraction phase with respect to indication, achieved expansion, additional procedures and side effects. In all cases the existing transverse maxillary deficiency was corrected by means of transpalatal distraction according to the individual needs. No complications were observed that interfered with that therapeutic aim. Evaluation of the records showed a wide variance of parameters which impedes evidence based statements. According to that series transpalatal distraction is a safe, powerful and reliable procedure and can be recommended as a state of the art procedure for the individually adapted correction of transverse maxillary deficiency if well known parameters of distraction are respected.

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

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.

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.