Relationship of mandibular anterior tooth apices to genial muscle attachments

Improved surface EMG electrode for measuring genioglossus muscle activity

Activation of the genioglossus (GG) muscles is necessary to maintain the patency of the upper airway. In the condition of obstructive sleep apnea (OSA) this mechanism fails and the possible role of fatigue in its pathogenesis is still not fully understood. In this paper, a new electrode design for recording the genioglossus surface electromyogram (sEMG) is presented. The new design differs from a widely used GG surface electrode in both electrode configuration (unilateral rather than bilateral) and electrode material (Ag-AgCl rather than stainless steel (SS)). The separate effects of these factors were evaluated during force-varying and fatiguing contractions on normal human subjects and using GG sEMG model simulations. Unilateral sEMG was found to have lower amplitude, lower frequency content and a different rate of change of median frequency during fatiguing contractions. It was shown to overcome several disadvantages posed by the bilateral configuration and be more selective. Ag-AgCl has more favorable impedance characteristics and resulted in greater signal amplitudes. It was concluded that the new design is more suitable for detecting GG sEMG and allows more reliable interpretation of changes in sEMG due to physiological mechanisms, thus providing a new methodology for studying GG function and the role of fatigue in OSA.

Anatomic and spiral computed tomographic study of the genial tubercles for genioglossus advancement

OBJECTIVE

To measure and compare Chinese mandibular genial tubercles measured anatomically and with computed tomography (CT).

STUDY DESIGN AND SETTING

Spiral CT scans were taken of 40 adult human skulls; the superior genial spines were measured using anatomic and CT methods.

RESULTS

The height and width of the superior genial spines, mandible thickness, and distance from the menton to the inferior and superior margins of the superior genial spines were 5.82 +/- 0.71, 6.98 +/- 1.35, 11.95 +/- 1.59, 11.08 +/- 2.05, and 16.91 +/- 2.30 mm from anatomic measurements and 6.17 +/- 0.71, 7.01 +/- 1.13, 12.19 +/- 1.64, 10.41 +/- 1.55, and 15.73 +/- 2.12 mm using spiral CT, respectively. The anatomic and CT measurements were correlated.

CONCLUSION

Spiral CT of the genial tubercles can help locate the osteotomy in genioglossus advancement.

SIGNIFICANCE

This study acquired reference data on Chinese genial tubercles demonstrating that CT measurements of the genial tubercles reflect their anatomy, which should allow accurately locate the osteotomy.

Obstructive sleep apnea surgery: genioglossus advancement revisited

PURPOSE

This study evaluated the accuracy of a genioglossus advancement (GA) technique (rectangular window) to incorporate the genial tubercle/genioglossus muscle complex (GGC) in patients with obstructive sleep apnea.

METHODS

This prospective study consisted of 38 consecutive patients who underwent GA. Preoperative localization of the GGC was based on the cephalometric and panoramic radiographs, as well as digital palpation in the floor of mouth. Immediately after completion of the osteotomy, the presence of the genial tubercles and the amount of the genioglossus muscle captured in the bone flap were examined directly.

RESULTS

All 38 pairs of genial tubercles were captured. Thirty-one patients had both bellies of the genioglossus muscle incorporated. Two patients had a complete belly and a partial (>50%) belly of the muscle captured. Five patients had only a portion (>50%) of both muscle bellies included. The incomplete incorporation of the muscles in the bone flap was caused by the limited lateral extension of the osteotomy beyond the genial tubercles. The causes of the limited lateral osteotomy extension included crowding of the lower incisors as well as the presence of elongated and/or medially angulated canine roots.

CONCLUSION

The results of this study show that the rectangular osteotomy technique accurately captures the genial tubercles and enables an adequate amount of the genioglossus muscle to be incorporated and advanced. However, limited lateral extension of the osteotomy can result in a decreased incorporation of genioglossus muscle in some patients.

Orthodontic-surgical correction of a Class II, Division 2 malocclusion

The incorporation of the total subapical osteotomy as an alternative surgical technique to augment standard bilateral sagittal split osteotomy in facilitating establishment of the profile objectives in the surgical-orthodontic treatment of a patient with skeletal sagittal discrepancy, is presented in this case report. Esthetic considerations, as well as risks involved in this type of a combined surgical approach, are also discussed.