Genial tubercle position and genioglossus advancement in obstructive sleep apnea (OSA) treatment: a systematic review

Background

To systematically review the literature for methods to localize the genial tubercle as a means for performing an advancement of the genioglossus muscle.

Methods

PubMed, Google Scholar, CRISP, EMBASE, CINAHL, and Scopus were searched from inception through June 16, 2015.

Results

One hundred fifty-two articles were screened, and the full text versions of 12 articles were reviewed in their entirety and 7 publications reporting their methodology for localizing the genial tubercle. Based upon these measurements and the results published from radiographic imaging and cadaveric dissections of all the papers included in this study, we identified the genial tubercle as being positioned within the mandible at a point 10 mm from the incisor apex and 10 mm from the lower mandibular border.

Conclusion

Based upon the results of this review, the genial tubercles were positioned within the mandible at a point 10 mm from the incisor apex and 10 mm from the lower mandible border. It may serve as an additional reference for localizing the genial tubercle and the attachment of the genioglossus muscle to the mandible, although the preoperative radiological evaluation and the palpation of the GT are recommended to accurately isolate.

Skeletal Surgery for Obstructive Sleep Apnea

Multilevel surgery has been established as the mainstay of treatment for the surgical management of obstructive sleep apnea (OSA). Combined with uvulopalatopharyngoplasty, tongue-base surgeries, including the genioglossus advancement (GA), sliding genioplasty, and hyoid myotomy and suspension, have been developed to target hypopharyngeal obstruction. Total airway surgery consisting of maxillomandibular advancement (MMA) with/without GA has shown significant success. Skeletal procedures for OSA with or without a palatal procedure is a proven technique for relieving airway obstruction during sleep. A case study demonstrating the utility of virtual surgical planning for MMA surgery is presented.

Intraosseous monitoring and guiding by ultrasound: a feasibility study

An efficient method for navigation within bone tissue boundaries is essential for performance of surgical procedures, e.g. without damaging of adjacent vulnerable organs. The application of sonographic measuring methods for this purpose promises to be effective in the ability to distinguish soft trabecular bone from dense cortical bone, owing to an order of magnitude difference in acoustic density between these structures. For this purpose, a specific method was developed that utilizes propagation of a 5 MHz ultrasonic wave through an aqueous milieu. Using this method a 0.2mm resolution in measurements is achieved. This resolution is in an order of magnitude lower than is required for a clinical use. A three-stage experimental approach was adopted: measurements in a cubic "phantom" made of a transparent plastic material, in samples of fresh porcine femora, and in a clinical setting of drilling in the upper and lower jaw during dental implantation surgery in nine patients. Two patterns of the detected ultrasound wave reflections were found: low amplitude reflections from the aqueous surrounding and trabecular bone and highly reflected ultrasound waves from the cortical bone. We show that trabecular and cortical bones are distinguishable by real-time ultrasonic measurement. The distances of the drilled tracts, in the range of 58.0-122.0 mm for the "phantom" experiment, 22.6-35.5 mm for the ex vivo experiment and 10.0-11.5 mm in the clinical experiment, and residual distances to the opposite edge of the tested samples and organs, in the range of 21.0-82.0 mm for the "phantom" experiment, 3.8-11.36 mm for the ex vivo experiment and 2.1-6.9 mm in the clinical experiment, were measured by the presented sonographic method and compared statistically, using linear correlation and Bland Altman plot, to the mechanical and/or radiographic measurements in all three stages of the experiment. A correlation coefficient above 0.95 was considered an indication of high correlation, while a value of 0.75-0.94 was considered intermediate, and a value below 0.75 was considered poor. A very high correlation (p < 0.001) and agreement between the sonographic and the "gold standard" measurements techniques, either mechanical or radiographic depending on the experimental setting, were found. Therefore the presented method of intraosseous sonographic measurements may provide an improved method for the monitoring of intraosseous drilling in respect of the currently used mechanical and/or radiographic clinical methods.