Sigmoid Notch Research Articles

Second branchial cleft anomaly – A rare clinical presentation

The elbow joint is a compound joint made of articulations in between the humerus, ulna and the radius. The coupling areas (joints) are of prime importance from the kinetic-biomechanical perspective and of potential inter-ethnic significance. These articulations can be affected by several pathologies that may require medical and surgical interference. This experimental analysis aims to infer data in relation to the morphometry of the proximal segment of the ulna and its articular surfaces represented by the greater sigmoid notch (trochlear notch) and lesser sigmoid notch (radial notch).A sample of fifty ulnae (n = 50, 27 right and 23 left) was studied in connection with; the surface area of the sigmoid notches (SA), weight of ulna, and the volume of proximal portion of ulna (including the olecranon process and reaching inferiorly to the lowest margin of the radial notch), the length of ulna (L). Longitudinal dimensional parameters were also studied including; the straight distance between the highest point (tip) of the olecranon and that of the coronoid process (OCD), and the mid-olecranon thickness in mediolateral (T1) and anteroposterior orientation (T2).It has been inferred that there were no significant differences in between right versus left ulnae and in relation to the majority of morphometric parameters with an exception for OCD (22.47 vs 20.75, p-value = 0.002). There was a positive correlation in between all the parameters, although the strongest associations were observed in between OCD, the area of the trochlear notch, and the weight of ulna.A precise conclusion was reached in relation to morphometry, volumetry and the pertinent biomechanics of the proximal segment of the ulna. Key findings are of value to biomedical engineers, medical professionals including orthopaedic surgeons and rheumatologists, evolutionary biologist, and physical anthropologist. Data from this study can be used to (reverse) engineer the perfect implant for the elbow joint.

Mandibular condylar hypoplasia in children with isolated unilateral congenital aural atresia.

We hypothesized that children with isolated nonsyndromic unilateral congenital aural atresia have subclinical mandibular condylar hypoplasia ipsilateral to the atretic ear, and that the Jahrsdoerfer score is associated with the degree of condylar hypoplasia. Retrospective self-controlled case series. We reviewed high-resolution computed tomography scans of the temporal bones of 68 children with isolated nonsyndromic unilateral congenital aural atresia. Images were viewed in the transverse (axial) plane perpendicular to the axis of the mandibular ramus and scanned from the mandibular notch to the condylar top. The slice where the condyle had the largest cross-sectional area was measured and checked for correlation with atresia status, age, and sex. The Jahrsdoerfer score of the atretic ear was calculated and correlated with condyle cross-sectional area, age, and sex. Cross-sectional area of the condyle ipsilateral to the atretic ear was, on average, 8.41 mm2 smaller than the contralateral condyle (P < .0001). The Jahrsdoerfer score was not associated with the condylar cross-sectional area, age, or sex. Isolated nonsyndromic unilateral congenital aural atresia is associated with mild hypoplasia of the mandibular condyle ipsilateral to the atretic ear. This is consistent with the hypothesis that congenital aural atresia is a variant of craniofacial (hemifacial) microsomia. 4. Laryngoscope, 128:1191-1195, 2018.

Finite Element Evaluation of Stable Fixation in Combined Mandibular Fractures

The fixation of combined mandibular fractures, especially symphyseal-condylar fractures, although occurring commonly and having a higher complication rate in the clinic, is rarely investigated regarding predictable therapeutic approaches. Thus this study's aim was to assess different forms of condylar fixation when combined with symphyseal fracture fixation. Using finite element models, we analyzed the stress distribution that occurs when a condylar fracture is fixed with 1 miniplate, 2 miniplates, or a trapezoidal condylar miniplate and when a symphyseal fracture is fixed with 2 parallel plates, 2 perpendicular plates, or 2 lag screws. The null hypothesis was that there would be no differences among the different fixation techniques. The results showed a stress concentration in the anterior region of the condyle, close to the sigmoid notch. Moreover, adequate fixation in the symphysis could result in less tension at the condylar region. Therefore, when the symphysis was fixed with a lag-screw technique, condylar fixation was less required, showing a more adequate stress distribution when the condyle was fixed with 1 or 2 plates. Conversely, when the symphyseal fixation was less effective, by use of perpendicular plates, there was a change in the stress distribution at the condylar region, altering fixation behavior and resulting in more tension and displacement in the condyle, especially when a trapezoidal plate was used. A lag screw and parallel double plates appear to be suitable for symphyseal fixation, whereas 2 straightly positioned plates and a trapezoidal plate are suitable for condylar fixation. However, the combination of perpendicular plates in symphyseal fixation and a trapezoidal plate in condylar fixation showed an altered stress distribution.

Detections of Screw Penetration during Volar Plating for Distal Radius Fractures.

Background We evaluated the detection for screw penetration on the dorsal cortex of the radius in serial oblique, dorsal tangential, and radial groove radiographic views in volar plating fixation. Materials and Methods Eight screw positions were set in each of the four cadaveric radii. Screw 1 was placed in the styloid subregion, whereas screws 2 and 3 were placed just proximal to the styloid and were defined for the radial region of the radius. Screws 4 (distal to the extensor pollicis longus [EPL] groove), 5 (the distal half of the groove), and 6 (the proximal half of the groove) were placed in the central region of the radius. Screws 7 (just medial to the groove) and 8 (sigmoid notch subregion) were positioned in the ulnar region of the radius. The screws were overlengthened by 1 and 2 mm and were evaluated in three radiographic views. Results Penetrations in the radial region were fully visible in supinated oblique views with 1- and 2-mm overlengthened screws. The penetration of screw 4 was clearly observable over a considerable range of views. However, the 1-mm penetration of screw 5 was not detectable at any angle of projection. Detection of the ulnar region screw was the most difficult among the three regions with oblique views. In the dorsal tangential view, the 1-mm penetration of screw 4 was not observed in any of the four radii, but the penetration of screw 5 was detectable in all the radii. The screws 2, 3, 5, 7, and 8 were readily detectable. The screw 4 was barely seen in the radial groove view, while the screws 5 and 6 were readily detectable. Conclusion/Clinical Relevance Appropriate combinations of these well-known radiological views are essential for the overall detection of penetrated screws during plating in distal radius fractures.

Assessment of Distal Radioulnar Joint Stability After Reconstruction With the Brachioradialis Wrap

The brachioradialis (BR) wrap technique is an option to restore the stability of the distal radioulnar joint (DRUJ). The technique capitalizes on the BR's advantageous insertion point on the radial styloid and the ability of the BR to be harvested with minimal to no deficit. The tendon can then be wrapped around the radius and ulna, tunneling under the pronator quadratus and extensor compartments and secured back into its insertion to provide stability. In this cadaveric study, we used micro-computed tomography (CT) to assess the stability restored by this procedure. Axial CT scans were taken of cadaveric specimens (n = 10) in 3 different positions (neutral, 60° pronation, and 60° supination) to establish the baseline measurements of each DRUJ. Surgical disruption of the dorsal and volar ligaments of each DRUJ then simulated a destabilizing injury and the specimens were scanned again. The specimens then underwent the BR wrap procedure and were scanned once more. Degree of ulnar subluxation with respect to the Sigmoid notch was determined using the modified radioulnar line method. The mean percentages of subluxation in the neutral position for the normal, injured, and reconstructed DRUJ were 22.4±4.9%, 56.2±12.9%, and 29.0±6.5%, respectively. In 60° pronation, these values were 15.4±4.7%, 53.5±15.0%, and 36.5±11.8%, respectively. In 60° supination, these values were 18.6±2.5%, 69.7±20.5%, and 31.9±8.7%, respectively. Values differed significantly between normal and injured conditions in all positions. No significant difference was noted between normal and reconstructed conditions, suggesting reconstruction improves DRUJ biomechanics and more closely approximates normal stability.

Kiefergelenkfortsatzfrakturen nach der AO-CMF-Trauma-Klassifikation

Im Prazisionslevel 3 der AO-CMF-Trauma-Klassifikation werden Kiefergelenkfortsatzfrakturen in Frakturen des Gelenkkopfs (Walze, Capitulum), des Gelenkhalses und der Gelenkfortsatzbasis unterteilt. Kopffrakturen weisen 2 typische Bruchverlaufe auf. Bei einer Fraktur im medialen Walzenbereich (Frakturtyp m) bleibt die Relation lateraler Kondylus zu Fossa und Diskus i.d.R. erhalten. Eine Fraktur im Bereich des lateralen Walzenpols (Frakturtyp p) ist ublicherweise mit einem Hohenverlust assoziiert; der Diskus mit dem kleinen (proximalen) Fragment wird nach anteromedial disloziert, was mit oder ohne Verletzung des lateralen Kapselansatzes einhergehen kann. Die Frakturmorphologie wird neben dem Hohenverlust durch die Attribute Fragmentation („minor“, „major“), vertikale Fragmentapposition sowie Dislokation, Luxation und Distorsion des proximalen Fragments in Bezug auf die Fossa naher definiert. Gelenkfortsatzbasis- und Gelenkhalsfrakturen werden gemas einer neuen Ein-Drittel- zu Zwei-Drittel-Regel fur den Frakturverlauf ober- bzw. unterhalb der sog. Loukota-Linie („sigmoid notch line“) differenziert. Attribute zur Definition der Morphologie sind auch hier das Vorliegen einer Luxation oder Dislokation und deren Richtung, die Angulation des gelenktragenden Fragments und Parameter wie Fragmentation, Hohenverlust und Dislokationen in der Kondylus-Fossa-Relation.

Are Biodegradable Plates Applicable in Endoscope-Assisted Open Reduction and Internal Fixation of Mandibular Subcondyle Fractures?

To investigate whether biodegradable plates are applicable in endoscope-assisted open reduction and internal fixation (EAORIF) of mandibular subcondyle fractures. This retrospective case-series study included patients with mandibular subcondyle fractures treated with EAORIF using an unsintered hydroxyapatite particles/poly-l-lactide biodegradable plate system, with at least 6months of clinical follow-up data available. The outcome variables were fracture healing with postoperative stability and postoperative complications. Other variables included age, gender, fracture site, cause of injury, accompanying mandibular fracture, total follow-up period, fracture classification, extent of displacement, preoperative status of occlusion, preoperative mandibular movements, fixation materials in accompanying mandibular fracture, location and number of fixation plates, periods of intermaxillary fixation/elastic bands, and postoperative mandibular movements. Fracture healing in these patients was assessed by comparing the immediate postoperative cone-beam computed tomography (CBCT) images with those obtained at least 3months after surgery. A total of 11 patients, 9 male and 2 female, with a mean±standard deviation age of 35.3±15.9years, were included. The mean follow-up period was 18.8±7.8months. Four patients had an accompanying mandibular fracture. Two 4-hole, 2.0-mm biodegradable plates were fixed with 6-mm screws along the posterior border of the mandibular ramus and near the sigmoid notch. Complete bone formation around the fracture lines or fading of the fracture lines, with no change in the position of the fractured segments, was observed on the postoperative CBCT images at 3months. With the exception of 2 patients, no patient complained of plate palpability, deviation in occlusion, or discomfort during the postoperative follow-up period. EAORIF using biodegradable plates for mandible subcondylar fractures is a stable and reliable method, with considerable advantages compared with titanium plates.

Measuring the condylar unit in condylar hyperplasia: from the sigmoid notch or from the mandibular lingula?

The objective of this study was to determine, in patients with active unilateral condylar hyperplasia, which is the most reliable point to measure the length of the condylar unit: from the sigmoid notch or from the mandibular lingula to the condylar head. On cone beam computed tomography, an observational cross-sectional study was designed for 20 patients with active unilateral condylar hyperplasia. We measured and compared ramus length (affected and healthy sides) and condylar length (measured from the mandibular lingula and from the mandibular sigmoid notch) on both sides. The average of all the differences in ramus height (D.1) was 7.97mm; the average of all the differences in condylar heights measured from mandibular lingula (D.2) was 7.16mm, and measured from the sigmoid notch (D.3) was 4.89mm. No significant difference between D.1 and D.2 (P=0.818). There was a significant difference between D.1 and D.3 (P=0.005) and between D.2 and D.3 (P=0.0005). It can be concluded that the mandibular lingula is the lowest point of the condylar skeletal unit and is therefore a stable parameter to be used in patients with condylar hyperplasia. On the other hand, the sigmoidal notch is not a stable parameter in patients with asymmetry due to condylar hyperplasia.

Mandibular Lesions

The mandible is a physiologically complex bone that plays a role in phonation, mastication, and jaw stability. It is a strong flat bone that serves as an anchor for the lower dentition and an attachment site for masticator muscles and facial muscles. The mandible is composed of multiple bony segments including a U-shaped body segment that fuses in the anterior midline at the symphysis menti and extends posteriorly to the vertical ramus segments. Each ramus connects to the body through the angle. The ramus extends cranially to form the coronoid process and mandibular condyle, which are separated by the mandibular notch. The mandibular condyle articulates with the temporal bone at the glenoid fossa forming the temporomandibular joint. The outer cortical bone of the mandible is known as the buccal surface, and the inner cortex is known as the lingual surface. Between the two cortices, there is trabecular bone and the alveolar canal, which carries the mandibular nerves. The mandible is a common site for more than 30 different lesions.1 Multiple lesion classifications have been proposed, including classifications based on origin (odontogenic vs. nonodontogenic); location; appearance (cystic vs. solid); or pathology. Understanding all of the mentioned classifications is by far the best approach to appreciate the complex overlapping pathologies.

Three-dimensional analysis of mandibular condyle position in patients with deviated mandibular prognathism

The purpose of this study was to evaluate the bilateral difference in condyle position in patients with deviated mandibular prognathism. Patients with asymmetrical (n=28) and symmetrical mandibular prognathism (n=23) were compared using the three-dimensional (3D) reformatted image from cone beam computed tomography. Significant positional differences in the condyle and subcondyle region (sigmoid notch) were found between the deviated and contralateral sides in the group with asymmetrical mandibular prognathism, but not in the control group. The lateral condyle was more laterally and inferiorly positioned on the contralateral side than on the deviated side (P<0.05). The sigmoid notch was more laterally, superiorly, and posteriorly positioned on the deviated side (P<0.01). Interestingly, condyle width and height on the deviated side was narrower and shorter than on the contralateral side and in the control group. Menton deviation was closely correlated with the bilateral difference in condyle height and 3D position of the sigmoid notch (P<0.01). The degree of asymmetry was more highly correlated with condyle height than with the spatial orientation of the condyle head. The results demonstrated that mandibular prognathism with asymmetry is associated with bilateral differences in 3D morphology and orientation of the condyle. Therefore, clinicians should consider these variations during surgical planning.

The influence of cartilage thickness at the sigmoid notch on inclination at the distal radioulnar joint.

The aims of this study were: firstly, to investigate the influence of the thickness of cartilage at the sigmoid notch on the inclination of the distal radioulnar joint (DRUJ), and secondly, to compare the sensitivity and specificity of MRI with plain radiographs for the assessment of the inclination of the articular surface of the DRUJ in the coronal plane. Contemporaneous MRI images and radiographs of 100 wrists from 98 asymptomatic patients (mean age 43 years, (16 to 67); 52 male, 53%) with no history of a fracture involving the wrist or surgery to the wrist, were reviewed. The thickness of the cartilage at the sigmoid notch, inclination of the DRUJ and Tolat Type of each DRUJ were determined. The assessment using MRI scans and cortical bone correlated well with radiographs, with a kappa value of 0.83. The mean difference between the inclination using the cortex and cartilage on MRI scans was 12°, leading to a change of Tolat type of inclination in 66% of wrists. No reverse oblique (Type 3) inclinations were found when using the cartilage to assess inclination. These data revealed that when measuring the inclination of the DRUJ using cartilage, reverse oblique inclinations might not exist. The data suggest that performing an ulna shortening osteotomy might be reasonable even in distal radioulnar joints where the plain radiographic appearance suggests an unfavourable reverse oblique inclination in the coronal plane. We recommend using MRI to validate radiographs in those that appear to be reverse oblique (Tolat Type 3), as the true inclination might be different, thereby removing one possible contraindication to ulnar shortening. Cite this article: Bone Joint J 2017;99-B:369-75.

Impact of Distal Ulnar Fracture Malunion on Distal Radioulnar Joint Instability: A Biomechanical Study of the Distal Interosseous Membrane Using a Cadaver Model

Certain distal ulna fractures may contribute to distal radioulnar joint (DRUJ) instability. We hypothesized that residual distal ulna translation could affect DRUJ stability by slackening the distal interosseous membrane (DIOM). We aimed to test this hypothesis in a cadaver model. We created an ulnar translated distal ulna fracture model in 6 cadavers. Dorsal and palmar displacements of the ulna relative to the radius were measured and DRUJ instability was staged under the following conditions: (1) 0-, 2-, and 4-mm ulnar translation of the distal ulna with an intact triangular fibrocartilage complex (TFCC) and DIOM; (2) 0-, 2-, and 4-mm translations with TFCC divided and an intact DIOM; and (3) a 0-mm translation with TFCC and DIOM divided. With an intact TFCC, dorsal and palmar displacements were not increased with any amount of distal ulna translation. After TFCC division with 0-mm translation, dorsal displacement increased significantly with DRUJ dislocation, whereas palmar displacement increased to a lesser extent with DRUJ subluxation. Palmar displacement gradually increased as the translation increased, and with 4-mm translation the ulnar head displaced to a perched position off the sigmoid notch. With TFCC and DIOM division, displacements increased markedly with DRUJ dislocation both dorsally and palmarly. Dorsal dislocation occurred when the TFCC was divided regardless of the amount of distal ulna translation. Palmar subluxation occurred when the TFCC alone was divided. Palmar displacement to a perched position occurred because of slackening of the DIOM as a result of translation of the distal ulna. Bidirectional DRUJ instability with dorsal dislocation and palmar displacement to a perched position occurred when the TFCC was divided and the distal ulna was ulnarly translated. Bidirectional DRUJ instability might occur when distal ulna translation deformity is associated with TFCC injury because the DIOM loses its function as a secondary stabilizer.

Non-constrained implant arthroplasty for the distal radioulnar joint.

A variety of surgical techniques are used to treat the arthritic distal radioulnar joint, which is influenced by aetiology and previous procedures. Four types of ulnar head arthroplasty exist: total ulnar head, partial ulnar head, unlinked total distal radioulnar joint, and linked distal radioulnar joint. Although long-term outcome studies are sparse, short-term clinical and biomechanical studies have shown encouraging results, leading to expanded indications. Based on our experience and a literature review, patients are advised that pain is improved but minor pain is common after strenuous activity. Ulnar neck resorption is common, however, implant loosening is rare. Sigmoid notch erosion is concerning, but appears to stabilize and not affect outcome. A partial ulnar head replacement that retains bony architecture and soft tissue restraints may have benefit over a total ulnar head in appropriate patients. If appropriate selection criteria are met, ulnar head replacement typically produces reliable results, with low revision.

Radial shortening osteotomy reduces radiocapitellar contact pressures while preserving valgus stability of the elbow

Shortening osteotomy of the proximal radius might represent a potential salvage procedure in symptomatic radiocapitellar osteoarthritis, which could decrease radiocapitellar load while preserving the native radial head. In an in-vitro biomechanical investigation, we sought to determine whether shortening osteotomy of the proximal radius (1) decreases the radiocapitellar joint pressure upon axial loading and (2) retains valgus stability of the elbow. In addition, the anatomic configuration of the lesser sigmoid notch was evaluated to assess possible contraindications. Axial loading (0-400N) and valgus torque (7.5Nm) over the full range of motion were applied to 14 fresh-frozen specimens before and after shortening osteotomy of the proximal radius by 2.5mm. Radiocapitellar and ulnohumeral load distribution during axial compression was evaluated using a digital pressure mapping sensor. Valgus displacement was analyzed with a 3D camera system. The inclination angle (α) of the lesser sigmoid notch was assessed via 50 CT scans. Up to axial loading of 250N, shortening osteotomy caused a significant decrease in radiocapitellar contact pressures (p < 0.041). Valgus stability of specimens did not differ before and after shortening osteotomy (n.s.). The mean inclination angle (α) of the lesser sigmoid notch was 11.3° ± 6.3°. 46% had an inclination angle of ≤ 10° (type I). 46% had an inclination angle of 11°-20° (type II). In 8%, the inclination angle was >20° (type III). Shortening osteotomy of the proximal radius can decrease radiocapitellar contact pressures during axial loading of up to 250N. Primary valgus stability is not relevantly influenced by this procedure. In few patients, shortening osteotomy may cause radioulnar impingement of the radial head at the distal edge of the lesser sigmoid notch due to an inclination angle of >20°. Shortening osteotomy might be a promising treatment option to decrease pain levels in case of isolated radiocapitellar osteoarthritis.

Three-Dimensional Analysis of Long-Term Stability After Bilateral Sagittal Split Ramus Osteotomy Fixed With a Single Miniplate With 4 Monocortical Screws and 1 Bicortical Screw: A Retrospective 2-Center Study

This study evaluated the long-term stability of bilateral sagittal split ramus osteotomy fixed with a single miniplate with 4 monocortical screws and 1 bicortical screw (hybrid technique [HT]) using 3-dimensional (3D) analysis and an objective measuring tool, cone-beam computed tomography (CBCT). Sixty-four patients who underwent bimaxillary surgery with mandibular advancement fixed with the HT were selected from 2 different institutions and enrolled in this retrospective study. All patients underwent CBCT preoperatively, 1month after surgery, and 12months after surgery. To estimate the long-term stability of the HT, volumetric comparisons were performed using the following measurements: distance between the gonion and the B point in the sagittal plane; distance between the right and left gonion transversally; and the angle of the line connecting the mandibular notch and the gonion and the line connecting the gonion and the B point vertically. Statistical analysis showed no relevant relapse (<1mm or <1°) when using the HT. However, a positive correlation between the amount of advancement and the amount of postoperative relapse was observed. The HT produces stable postoperative 3D results after 12months.

Morphological variations of the coronoid process, condyle and sigmoid notch as an adjunct in personal identification

Morphological variations of the coronoid process, condyle and sigmoid notch as an adjunct in personal identification

Reinvestigation of the Morphological Characteristics of the Lateral Ulnar Collateral Ligament in Humans.

To clarify the cause of posterolateral rotatory instability after damage to the lateral ulnar collateral ligament (LUCL), the morphological characteristics of the LUCL were reinvestigated and three-dimensional (3D) image of the ligament was reconstructed using 35 human elbows. The results were as follows: 1) the insertion point of the LUCL on the humerus was almost at the center of the capitellum, and its width was 2.61 ± 1.02 mm. The insertion point of the LUCL on the ulna was located from the lesser sigmoid notch to the supinator crest and had a width of 9.0 ± 2.8 mm. The proximal insertion of the LUCL on the ulna was 7.0 ± 3.0 mm, and the distal part was on the articular surface of the radial head. 2) Three-dimensional imaging of the LUCL revealed an anterior curved shape that covered the radial head. Based on these results, it was clear that both the supinator crest and the lesser sigmoid notch could be useful as osseous landmarks. We think that these anatomical results are useful for surgeons performing LUCL reconstruction.

Osteochondroma of the sigmoide notch: a case report of an unusual location

Objective: This article presents an interesting case of osteochondroma of the the sigmoid notch.Case Report: A 15-year-old female with severe facial asymmetry, malocclusion, open bite and extreme limitation of mouth opening. Panoramic radiography showed an exophytic radiopaque mass arising from the sigmoid notch on the right side. CT images revealed bony proliferation with benign signs causing damage to the articular eminence, condilar morphology and periarticular soft tissue calcifications. Magnetic Resonance confirmed the findings of the CT and revealed modifications on disc morphology. A surgical resection was performed.Conclusion: The OC located at the sigmoid notch presented is probably the rarest site seen in the existing literature.

Establishment and application of a digital workflow in the treatment of condylar osteochondroma and secondary dentofacial deformities using image-guided endoscopic navigation combined with orthognathic surgery

Objective: To establish a digital workflow in the treatment of mandibular condylar osteochondroma with secondary dentofacial deformities using navigation and endoscope combined with orthognathic surgery. Methods: Thirty-six patients with unilateral condylar osteochondroma were analyzed retrospectively. Preoperative planning and simulation were carried out on the digital three-dimansional (3D) model in all patients. With the aid of image-guided endoscopic navigation, osteochondroma resection and condylectomy were accurately performed. Secondary dentofacial deformities were simultaneously corrected using orthognathic surgery. All patients were followed up regularly and received postoperative CT scans. The preoperative simulated model and the postoperative actual model were matched using ProPlan CMF 2.0 software. Four corresponding points were marked in the virtual and actual ostectomy plane, respectively. The intersections of mandibular sigmoid notch and posterior ramusrim with condylectomy plane were marked as the anterior point and the posterior point, respectively. The perpendicular bisector of the line from the anterior point to the posterior point was intersected with the lateral and medial margin of condylectomy plane to form the lateral point and the medial point, respectively. The straight-line distances between the corresponding points in the virtual and actual ostectomy plane were respectively measured to analyze the ostectomy discrepancy. Results: All of 36 patients obtained satisfactory clinical effects. Facial symmetry and morphology were greatly improved. Postoperative CT showed that condylar tumors were completely removed. The preoperative simulated model and the postoperative actual model were matched. The average discrepancy between the planned and actual surgical resection was minimal on the anterior points ([0.24 ± 0.17] mm) and the mean error was maximal on the posterior points ([3.86±1.03] mm). The patients showed no signs of tumor recurrence in the 6 to 12 months of follow-up. Conclusions: Endoscope-assisted and navigation-guided tumor resection and condylectomy combined with simultaneous orthognathic surgery has satisfactory clinical effects in the treatment of condylar osteochondroma and secondary dentofacial deformities. The digital management workflow reported in this paper provides us a valuable option for this potentially complicated procedure.

Ectopic third molars in the sigmoid notch: etiology, diagnostic imaging and treatment options.

BackgroundThe etiology of ectopic third molars located in the sigmoid notch of the mandible is unclear. Only a few cases have been reported. The aim of this article is to discuss the etiology as well as treatment options and diagnostic imaging techniques.MethodsA PubMed and Medline search of the literature from 1965 to 2015 to ectopic third molars in the mandibular notch was performed. Furthermore, a clinical case provided by the authors is reported.ResultsAmong the eight reviewed cases, two male and six female patients were affected that ranged from 25 to 62 years of age (mean 48.4). Pain and swelling in the preauricular region or trismus but also the absence of symptoms was reported. Only in two of the summarized articles an extra-oral access for the removal of the tooth was used. The etiology seems to be individually different, however dentigerous cysts and chronic inflammation seem to play an important role in their appearance. While previous diagnostic reports described two-dimensional diagnostic imaging, currently the three-dimensional imaging is common for preoperative surgical planning with respect to removing ectopic molars.ConclusionsEctopic third molars in the mandible are a rare condition. The etiology seems to be individually different. Nowadays, three-dimensional imaging is common for preoperative surgical planning.