Genial Tubercle Research Articles

The Utility of 3D-printed Cutting Guides in Genioglossus Advancement

Genioglossus advancement is a surgical technique performed to treat obstructive sleep apnea. The genial tubercle, where the genioglossus muscle attaches, is not visible during dissection due to its location on the posterior mandible. Computer-aided design, particularly for the production of cutting guides, has arisen as a modern modification in the procedure to support accurate location of the tubercle. This study aims to demonstrate the utility of cutting guides designed by virtual surgical planning in a series of 7 genioglossus advancement cases. Computed Tomography (CT) data were preoperatively collected and rendered in three-dimension. The surgeon designed patient-specific cutting guides, registered to the occlusion, to ensure the genial tubercle was included in the osteotomy and stayed below the incisor tooth roots. These surgical guides were then 3D-printed. All the virtual surgical planning-designed guides fit appropriately, the genial tubercle was successfully included in the osteotomy in all cases, and no tooth roots were injured. We conclude that occlusal-based 3D printed cutting guides are a useful adjunct to help guide a genioglossus advancement procedure by accurately incorporating the genial tubercle. This provides a safe way to concurrently address correction of obstructive sleep apnea in patients undergoing other procedures.

3D Genial Tubercle Anatomic Considerations in Genioglossus Advancement Surgery.

To qualitatively describe variation in morphology of the genial tubercle and quantify the spatial relationship between the tubercle and genioglossus muscle. Case series. Cadaver dissection. Segmental sections of the mandible, with muscular attachments intact, were harvested from 18 fresh cadaver heads. Three-dimensional laser scans, with a resolution of 0.025 mm, were taken of each specimen with muscle attached and repeated after muscle removal. The genioglossus muscular attachment was measured relation to bony landmarks. The morphology of the genial tubercle varied, with anywhere from 1 large spine to 4 individual spines. However, all specimens had a distinguishable superior portion of the tubercle, where the genioglossus attached, and an inferior portion, where the geniohyoid attached. The height of the superior tubercle (ST) was 6.1 mm (95% confidence inerval [CI]: 5.7-6.5). The height of the genioglossus muscle above the peak amplitude of the ST was 4.3 mm (3.8-4.9), but only 2.5 mm (2.0-3.0) below. On average, 64.4% (58.6-70.2) of the height of the genioglossus muscle attachment was above the peak. Overall, 19.5% (14.1-25.0) of the muscle surface area extended beyond the boundaries of the tubercle. The genioglossus muscle attachment originates from the superior genial tubercle, which has a variable topography and amplitude. However, the muscle is not centered on the spines-more of the muscular fibers attach above the spine as compared to below. This new data may explain the genioglossus advancement "miss rate"-failure to advance muscle on initial osteotomy-of 39-78% reported in the literature.

A comparative investigation of three-dimensional printing models (rapid prototyping) made by imaging systems including multidetector computed tomography and cone-beam computed tomography systems

Abstract Introduction: Biomedical models (rapid prototyping) had a vast use in maxillofacial diagnosis and surgeries. Using this technology can lead to improvement in preoperative treatment planning and an increase in surgery quality. In this study, we investigated and compared the models derived from multidetector computed tomography (MDCT) and cone-beam computed tomography (CBCT) radiography systems. Aim: In this study, we investigated and compared the models derived from MDCT and CBCT radiography systems to see which is the most accurate. Materials and Methods: Five dried human mandibles were chosen in this study. These landmarks were chosen to investigate the reproduction ability: mental foramen, genial tubercle, central incisor, alveolar crest edge to the inferior mandibular border in midline, two bone defects in approximate dimensions of 3 × 3 mm2, first molar socket depth in the mesiobuccal line angle, mesiodistal length of tooth socket bone at the buccal and buccolingual width of tooth socket bone at mesial. Radiographs were taken using one MDCT and two CBCT systems. Then, models were built through a three-dimensional (3D) printer, and the mentioned landmarks were measured using a digital caliper. Data were entered in SPSS version 23 software and were analyzed with the ANOVA and Tukey tests. Results: In the reproduction of superior-inferior dimension and mesiodistal width of all mentioned landmarks, there were no significant differences between models made by data derived from Cranex 3D and NewTom 3G with a small field of view, in comparison with the gold standard (P > 0.05). However, there is a significant difference in the reproduction of landmarks between models made from MDCT and NewTom 3G with a large field of view, in comparison with the gold standard (P < 0.05). Conclusion: Models made from CBCT Devices with a small field of view have an acceptable and reliable accuracy for assessing bone structures. However, for CBCT devices with a large field of view and computed tomography-scan devices, models have less accuracy.

Cone Beam Computed Tomography Evaluation of Median Mandibular Lingual Canal in a Western Indian Subpopulation: A Cross-sectional Study

Introduction: The Mandibular Lingual Canals (MLC), which carry the sublingual artery, are present in the mandible near the genial tubercle. Identification of these canals is important before any dental surgical procedures. Aim: To identify and evaluate the mandibular lingual canal in Cone Beam Computed Tomography (CBCT) of the Western Indian Population. Materials and Methods: The current cross-sectional study was conducted at the Department of Oral Medicine and Radiology, Sumandeep Vidyapeeth, Vadodara, Gujarat, India between October 2022 and June 2023. A total of 100 CBCT volumes showing the mandibular anterior region were evaluated for the presence or absence of a mandibular lingual canal. The canals were further evaluated for their number, diameter, length, thickness of the buccal cortical plate, and the remaining bone above and below the canal. The evaluation was done by two separate investigators. The data were entered into Microsoft Excel and subjected to statistical analysis. Data collected were tested statistically using the Chi-square test. Results: A total of 59 males and 41 females’ mandibular CBCT volumes were evaluated, out of which 93 CBCT volumes showed the mandibular lingual canal. The maximum number (n=57) of individuals showed three canals, followed by two canals (n=26) and one canal (n=10). There was no statistical significance between genders regarding canal number, diameter, length, thickness of the buccal cortical plate, and the remaining bone above and below the canal. Conclusion: Three-canal morphology was the most common anatomical form of MLC found in the Western Indian population.

Customized Preliminary Impression: A Novel Impression Technique for Severely Resorbed Edentulous Ridges

Patients with long-term edentulism and/or ill-fitting (poorly fitted) dentures are more likely to experience severe mandibular alveolar ridge resorption. Some of these patients have genial tubercles that rise over the mandibular residual ridge in the anterior region and protrude into the floor of the mouth. Typically, the most prominent portions of the resorbed mandibular edentulous ridge are in contact with the lingual flanges of the mandibular stock impression trays (i.e., genial tubercles and internal oblique lines). In these situations, it is advised that a preliminary custom impression tray be created to pour an initial impression, allowing for the fabrication of individual custom trays. In general, dental practice for the fabrication of the complete denture, the stock trays are used for making the preliminary impression and the custom trays for the final impression. The present article portrays an innovative and efficient clinical technique involving the fabrication of a customized preliminary impression tray for preliminary impression making particularly in unconventional situations, that is, pronounced mandibular alveolar ridge resorption.

Should we be concerned about accessory mandibular foramina and canals? A cone-beam computed tomography study

Objective: Analyze the prevalence of mandibular accessory foramina and canals using cone-beam computed tomography (CBCT). Methodology: 136 mandibles divided into 10 predetermined areas were analyzed through CBCT looking for accessory foramina and canals. The Chi-square and Wilcoxon tests were used. Results: We found 1.316 accessory foramina, which 486 were accompanied by canals. 70.3% of accessory foramina were on the internal mandibular surface, most below the mylohyoid line and genial tubercles. The M1 area had the highest number of foramina, especially in the internal surface. The right mandibular side revealed a significantly greater number of foramina when compared to the left side. The mean diameter of accessory foramina analyzed was 0.85mm. Most of the accessory canals were on the internal mandibular surface, with a longer average length when compared to external surface canals. Conclusion: Our study showed that more detailed studies of accessory mandibular foramina and canals should be carried out, since a high prevalence of these structures and they have not named or classified yet. Furthermore, procedures that reach the internal mandibular surface, especially the anterior region, may be more subject to complications, as well as failure of anesthetic blocks on the right side of the mandible.

Pre-operative CT cephalometry and functional outcomes after open partial horizontal laryngectomy

To identify pre-operative radiological parameters that are able to predict the functional outcomes of open partial horizontal laryngectomy (OPHL). The present retrospective study concerned a cohort of 96 patients with laryngeal squamous cell carcinoma who underwent pre-operative radiological staging with contrast-enhanced computerised tomography of the neck, and subsequent supracricoid or supratracheal laryngectomy. Univariate and multivariate analyses were run to assess the prognostic value of the main demographic and surgical variables, and the pre-operative cephalometric values, respectively, in terms of predicting patients' functional outcomes. Multivariate analysis showed that a larger anteroposterior cross-sectional dimension of the aero-digestive tract in the mid-retroglossal area, and a greater distance between the genial tubercle and the hyoid bone in the mid-sagittal plane correlated significantly with better functional outcomes in terms of decannulation rate at discharge. Our findings show that larger pre-operative upper aero-digestive tract diameters and volumes coincide with better post-operative functional outcomes after OPHL.

Genioglossus Advancement: Technique Modification for Improved Chin Contour.

Genioglossus advancement plays an important role in the armamentarium of the obstructive sleep apnea surgeon and has gone through many iterations over several decades. A recently described technique involves creating a box osteotomy, which is carried through the inferior border of the mandible in order to increase recruitment of the suprahyoid musculature. Here we introduce a further modification of the technique that uses virtual planning to improve the safety and accuracy of genial tubercle capture. In addition, angulation of the lateral osteotomies enhances bone to bone contact. Before the osteotomy, the surgeon has the opportunity to drill the buccal plate to reduce the chin profile. This approach is particularly valuable in the patient who is prognathic at baseline or who becomes prognathic after simultaneous maxillomandibular advancement. Here we discuss this unique approach, demonstrating how the patient profile may be balanced even as the genial tubercle is advanced.

Morphometric aspects and proposal of a new classification of genial tubercles in cone-beam computed tomography in a Brazilian population.

This study evaluated epidemiological and morphological aspects of genial tubercles (GTs) using cone-beam computed tomography (CBCT). This retrospective, observational and cross-sectional study evaluated 276 tomographs of adult dentate individuals (18-69 years). The presence and absence of GTs were evaluated, and in cases in which this structure was observed, linear measurements (length, height, and width), and anatomical distances. In addition, a GT classification was proposed based on the presence, number, and location of the tubercles. Of the 276 CT scans, 28 (10.14%) had absence of GTs and in 248 CT scans GTs were present, of which 42 (57.5%) were from females and 106 (42.5%) from males. Regarding the number of GTS, the most prevalent variant was the two-tubercle-variant (143, 57.7%), followed by the presence of a single tubercle (n=62, 25.0%), 3 tubercles (n=40, 16.1%) and 4 tubercles (n=3, 1.2%). The most prevalent classification was IIIA (n=96, 38.7%), followed by IIIB (n=60, 36.3%), IIA (n=53, 21.4%) and IIB (n=9, 3.6%). A prevalence of GT of approximately 90% was observed, with two GTs per exam as the most frequent finding. Men had a longer mean GT length compared to women. Female individuals exhibited a shorter distance from the base of the GT to the base of the mandible.

Comparison of airway changes after maxillomandibular advancement with or without genial tubercle advancement in obstructive sleep apnea using cone-beam computed tomography

This study compared the airway changes of patients with obstructive sleep apnea (OSA) after maxillomandibular advancement (MMA) with or without genial tubercle advancement (GTA) using cone-beam computed tomography. The authors retrospectively studied 26 patients with moderate to severe OSA who underwent MMA with or without GTA. Airway changes were determined from preoperative and postoperative 3-dimensional reconstructed cone-beam computed tomography images. The Wilcoxon signed rank test, Mann-Whitney U tests, and Spearman correlation coefficients were used in data analysis. Airway was changed in all dimensions significantly after MMA with or without GTA. There was no significant difference in horizontal surgical changes between MMA and MMA with the GTA group. The mean increase in total airway volume was 66.8% for MMA alone and 74.7% for MMA with GTA (P= 0.39). Patients who underwent MMA had a larger percentage change of segmented upper airway volume than patients with MMA and GTA (106.6% vs 85.3%; P= 0.65). The group with MMA and GTA had a greater percentage change of segmented lower airway volume than the MMA alone group (80.1% vs 56.3%; P= 0.42). Differences in airway changes between MMA alone and MMA with GTA were not statistically significant. Performing the GTA concomitantly with MMA may not cause greater improvement in the pharyngeal airway in patients with OSA compared with MMA alone.

Prevalence and Anatomic Variations of Lingual Foramina and Lingual Canal in Anterior Mandible Using Cone Beam Computed Tomography – A Cross-Sectional Study

Introduction: Rich neurovascular supply in the anterior mandible necessitates a preoperative radiological assessment of the lingual foramina/canal where cone beam computed tomography (CBCT) could produce promising results. Aim: To assess the prevalence of lingual foramina and canal in mandible and variations in their anatomy in a hospital-based population in Chennai. Methodology: Sagittal sections of the anterior mandible from CBCT images of 140 patients were evaluated for number, location of the lingual foramen, length of the lingual canal, a distance of lingual foramen from the alveolar crest and inferior border of the mandible, and thickness of the lingual cortex. Results: A total of 166 lingual foramina-canals were identified in 140 individuals; 82.1% presented with one, 15.1% with two, and 2.1% with three lingual foramina canals. The majority of foramina (79.51%) were located above the genial tubercles. The mean lengths of the superior, middle, and inferior canals were 5.45 ± 1.34, 5.00 ± 1.73, and 3.92 ± 1.10 mm, respectively. The mean thickness of the lingual cortex was 2.35 ± 0.55 mm. The distance from the inferior lingual foramina to the alveolar crest was significantly greater in males (P = 0.001). Conclusion: Anatomical characteristics of lingual foramen-canal varied significantly across the total sample.

Evaluating the Stability of Type II Genial Tubercle Fracture Repair: A Case Report

This case explores the management of a type II genial tubercle fracture (GTF) repair and its stability. Few reports describing the surgical correction of this fracture type exist and among the available literature detailing GTF repair, most do not include post-surgical clinical follow-up. The case herein follows the treatment of a 35-year-old male sustaining poly mandibular trauma. Plate fixation, trans-osseous wiring and maxillomandibular fixation (MMF) were used to secure the genial tubercle to a stable mandibular complex. A 6-week closed reduction protocol was implemented for management of a concomitant subcondylar fracture. Although the patient displayed improvements clinically, genial tubercle (GT) displacement was seen radiographically at the completion of treatment. This paper aims to reassess the durability of trans-osseous wiring as a sole means of fracture reduction. Additional studies documenting follow-up evaluations are needed to verify treatment outcomes of this rare fracture pattern.

Evaluation of neurovascular anatomical variation in the anterior mandible in North Indian population: A CBCT assessment

IntroductionThe purpose of this retrospective study was to determine the visibility, location and other morphometric features of lingual foramina on CBCT along with its age wise and gender wise correlation. Material and methodsA total of 250 patients were included in the study. Cross-sectional CBCT images of the mandible in the midline were used to locate and define each detected lingual foramen and canal. Descriptive statistics including tables and graphs were used. Genderwise and Age wise correlations were analyzed using Chi-square tests. ResultsThe number, direction, length, diameter, distance from alveolar crest and inferior borders of mandible were evaluated. Genderwise Lingual foramen was most frequently located in the mandibular midline, above genial tubercle (81.7%). Agewise it was found to be significant (p = 0.019). Genderwise length of canal was found to be significant (p = 0.022). Genderwise diameter of canal at midpoint was found to be very highly significant (p < 0.001) and at innermost point was found to significant. (p = 0.037) Genderwise and Agewise distance between orifice of canal and alveolar crest was found to be very highly significant. (p < 0.001) Genderwise and Agewise distance between innermost point of canal and alveolar crest was found to be highly significant (p = 0.001) and very highly significant (p < 0.001) respectively. ConclusionClinicians may consider CBCT for procedures with a risk of hemorrhagic and neurosensory complications such as dental implant placement in the anterior mandible.

Airway Compromise in Mandibular Fracture.

Airway compromise is life threatening complication in the maxillofacial fracture. However, the incident of the airway compromise following mandibular fracture was little known. Maxillofacial fractures during the past 3 years from 2017 to 2020 were investigated retrospectively. There were 154 patients with maxillofacial fractures were noted in the past 3 years. Mandibular fractures accounted for 93% of the maxillofacial fracture. The most common cause of injury was falls (75%), followed by sports (12%). Of these, 3 cases (1.9%) needed an airway management at the time of initial treatment, and all were mandibular fractures. The average age was 55.7 ± 10 years and all were male. The cause of the injury was high-energy trauma including traffic accident and work-related injury. Endotracheal intubation was performed at the time of initial treatment. All cases were communicated mandibular fracture included symphysis and para-symphysis region, and the bone fragments including the genial tubercle were largely displaced inward.

Traumatic genial tubercle fracture: a case description with 9-month radiographic follow-up and a literature analysis.

Traumatic genial tubercle fracture: a case description with 9-month radiographic follow-up and a literature analysis.

Large oral cavity cancer with anterior mandible invasion: Describing radiographic and pathologic discrepancy

Objectives/Hypothesis—Large oral cavity carcinoma can invade the mandible in the absence of radiographic findings. We hypothesize that the anterior mandible is at a unique elevated risk of subclinical invasion secondary to specific anatomic factors, described herein. Methods—Adult patients managed from January 2012 to April 2020 ​at two large academic medical centers with large oral cavity carcinoma abutting anterior mandible were reviewed. A review of our institutional free flap databases was conducted selecting for bony reconstruction of anterior mandible defects. Cases were selected that did not have bone invasion seen on preoperative imaging but did have pathologic bone invasion on final pathology. Results—We present a Case series of four adult patients that were identified over the study duration. Subsites included three oral tongue and one floor of mouth. Three patients had squamous cell carcinoma and one patient had adenocarcinoma. Bony invasion was not appreciated on radiographic imaging, however final pathology demonstrated invasion in all patients. All patients had infiltrative pattern of mandibular invasion. Conclusions—Mandible invasion, including presence of tumor in the medullary space, is possible even in the absence of radiographic bone invasion. The genial tubercle and lingual foramen may serve as an avenue of tumor spread into the anterior mandible from large oral cavity carcinoma. Surgical management of the mandible should be considered in select cases of large oral cavity carcinoma without radiographic evidence of mandible invasion.

Frequency and anatomic variability of the mandibular lingual foramina: a cone-beam CT study

BackgroundTo evaluate the distribution of lingual foramina (LF) and their correlation with demographic characteristics and mandible width, shape, and bone thickness in Caucasian Italian patients subjected to cone-beam CT (CBCT).MethodsCBCTs were reviewed to assess the number of all LF, midline and lateral LF. We also assessed the relationship of the number of lateral LF with gender and mandibular width, shape, and bone thickness using the Chi Square test. A p value < 0.05 was considered statistically significant.Results Three-hundred patients (180 males; age range: 21–87 years) were included. The highest frequency per patient was of 2 LF (97/300, 32.3%), followed by 3 (81/300, 27%) and 4 (53/300, 17.7%). No LF were observed in 2/300 patients (0.7%), while the highest number was of 8 LF in one patient. The highest frequency of midline LF per person was of 2 LF (57.3%, 172/300), while the highest number per person was 5 LF in one patient (0.3%). The highest frequency of midline LF located above and below the genial tubercle was of 1 in 197/300 patients (65.7%) and in 169/300 patients (56.3%), respectively. Concerning lateral LF, the highest frequencies were of 0 (113/300, 37.7%) and of 1 (112/300, 37.3%). We did not observe any significant difference of the number of midline and lateral LF based on gender (P = .438 and P = .195, respectively) or mandible width (P = .069 and P = .114, respectively). The mandible shape was normal in 188 cases, with facial constriction in 42, lingual constriction in 54, and hour glass constriction in 16. The mean bone thickness was 10.76 mm in the symphysis, 10.92 mm in the right hemiarches, and 10.68 in the left hemiarches. No significant differences in the distribution of LF were observed also based on mandibular shape and bone thickness (both with P > .05).ConclusionsWe have shown the high variability of number and anatomic distribution of LF in an Italian group of patients subjected to CBCT without reporting any association with gender and mandible width, shape, and bone thickness.

PREVALENCE AND ANATOMICAL VARIATIONS IN THE MANDIBULAR LINGUAL CANAL IN A SAMPLE OF EGYPTIAN POPULATION USING CBCT: A CROSS-SECTIONAL STUDY

Aim: With the development of surgical procedures, as the mandibular anterior dental implants and chin surgeries, there has been an increase in complications associated with anatomical elements in this anterior area. One of the most dangerous complications is related to bleeding caused by injured vessels associated with the lingual foramen and canal, which can cause a compression of the airway. Methodology: Eighty-two CBCT scans for Egyptian individuals were collected from the data base available at the Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Cairo University. Scans were selected according to specific inclusion and exclusion criteria, they were interpreted by two oral radiologists and analyzed in the three planes axial, coronal and sagittal. The midline was drawn on the axial scan by a line passing through the convexity of the genial tubercle to the mental ridge. The procedure was then standardized by adjusting the slice thickness and the spacing between all cuts at 0.4mm. After determining the midline on the axial plane, from the sagittal plane five consecutive cuts were taken on each side of the midline, these cuts were used for the assessment of the prevalence and the number of lingual canals present.

English

BACKGROUND Analysis of genial tubercle anatomy using three-dimensional (3D) imaging can be valuable in preparation for genioglossus advancement in the treatment of obstructive sleep apnoea, estimation of the safe zone prior to implant surgery and evaluation of mandibular asymmetry. Hence the intention of the study was to analyse the morphological pattern, dimensions of genial tubercles and their position in the mandible using cone beam computed tomography (CBCT). METHODS A retrospective study was conducted on 100 patients scanned using Sirona Orthophos XG device in the Radiology department, Saveetha dental college and hospital. The genial tubercles were identified, morphological pattern of the genial tubercles was classified into four patterns and linear measurements of the genial tubercle height, width, position of genial tubercles on the mandible in the images were done. The collected data was tabulated and analysed using SPSS software. A paired t - test was used for intra examiner calibration and a chi-square test was used for comparison between genial tubercle patterns in both the sex. RESULTS On analysing the genial tubercle patterns, type I (44) was the most commonly seen followed by type II (24). Genial tubercles were not evident (type IV) in 20 patients. Type III (12) was least commonly seen among the pattern types. CONCLUSIONS The anatomy of genial tubercles is highly variable. The mean height of genial tubercles (GTH) measured was 5.36 mm and mean width of genial tubercles (GTW) measured was 5.24 mm. KEY WORDS Genial Tubercles, Anatomy, Cone Beam Computed Tomography, Mandible

Prosthodontic rehabilitation of atrophied edentulous mandible with enlarged genial tubercle with conservative management: A case report

Genial tubercles are the group of four small bony elevations located at the inner part of symphysis menti. Severe resorption mandibular ridge may lead prominent genial tubercle. This may cause a problem when a complete denture is planned for the patient. Usually, surgical removal of prominent genial tubercle before the prosthetic treatment is preferable. However due to certain systematic condition, surgical exposure was not considered. Following Case report describes a stepwise guide to prosthodontic rehabilitation of patient with prominent genial tubercle (7mm height, 11mm width) conservatively.