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Orthognathic Surgery in the Mobius Syndrome Patient
Poster Session angle to the pterygoid plate in relation to the lateral maxillary sinus wall, the surface area of the lateral pterygoid plate (mm2), and bone density in Hounsfield Units (HU) at the pterygomaxillary junction, piriform rim, and zygomatic buttress. Of the 87 patients, 47 were females and 40 were males. Age ranged from 14-68 and the median age was 22. Fractures of the pterygoid plates occurred in 48% (N=42) of patients. Of those, 17% (N=7) had high pterygoid plate fracture and 83% (N=35) had low pterygoid plate fractures. Of the 7 cases with high pterygoid plate fracture, 3 occurred with an oscillating saw, 2 with osteotome and 2 with manual down fracture. Mean of the reference points were done on all 87 patients. Table I Anatomical mean values of fracture population Reference Points Piriform-Base Line Lateral Plate Medial Plate A-P Thickness PMJ M-L Thickness PMJ Lateral Wall-PMJ Angle of PMJ Area of Lateral Wall (mm2) HU PMJ HU Zygomatic Buttress HU Piriform
R
L
35.1 11.2 9.0 3.7 7.5 31.2 100.6 211.7 352.5 486.7 735.7
34.9 11.3 8.8 4.0 7.0 31.4 94.3 205.3 252.2 508.7 729.7
Table II Anatomical mean values of non-fracture population Reference Points Piriform-Base Line Lateral Plate Medial Plate A-P Thickness PMJ M-L Thickness PMJ Lateral Wall-PMJ Angle of PMJ Area of Lateral Wall (mm2) HU PMJ HU Zygomatic Buttress HU Piriform
R
L
34.8 12.2 9.0 5.0 7.2 31.2 99.9 208.1 311.9 491.3 713.8
34.6 11.8 9.5 4.3 6.8 30.9 96.1 204.5 277.7 438.1 723.9
References: 1. Precious DS: Pterygoid Plate Fracture in Le Fort 1 Osteotomy With and Without Pterygoid Chisel: A Computer Tomography Scan Evaluation of 58 Patients. J Oral Maxillofacial Surgery 51:151-153, 1993 2. Fonseca RJ: Oral and Maxillofacial Surgery. Volume 2:232-248.
POSTER 38 Orthognathic Surgery in the Mobius Syndrome Patient R. M. Ulma: University of California, Los Angeles, School of Dentistry, S. L. Ratner, M. Wilson Mobius syndrome has been well described in the literature since von Graffe’s seminal report in 1880. It is defined by the congenital, non-progressive palsy of the sixth and seventh cranial nerves, with occasional involvement of other cranial nerves. Facial and abducens nerve involvement can be unilateral or bilateral, and paralysis can be partial or complete. The incidence of Mobius syndrome has not been determined, although it is estimated to occur in 1:50,000 live births, with an equal gender distribution. The pathophysiology of Mobius syndrome is not completely understood. It is attributed to brainstem dysfunction, caused by agenesis of the involved cranial nerve nuclei, prompted by either environmental or genetic causes. Despite its rarity, the dental and maxillofacial management of the Mobius patient warrants attention. The management of soft tissue manifestations in these patients, particularly treatment of facial muscle paralysis, is well described. The treatment of other common maxillofacial abnormalities, however, has not been studied as extensively. A recent search of the literature on the hard tissue management of Mobius patients afforded only three case reports on a total of four patients. Three patients who underwent dentofacial deformity correction with orthognathic surgery are presented. This is the largest case series on orthognathic surgery in the Mobius syndrome patient, performed at one institution by one surgeon. Common dental and maxillofacial features of the Mobius patient and pertinent surgical treatment planning recommendations are also discussed.
POSTER 39 The incidence of untoward pterygoid plate fracture has been reported to be as high as 87%.1 Pterygoid plate fracture happens nearly 50% of the time and 17% were high-level fractures. Based on our data, neither surgical technique nor anatomical variability played a significant contributing role to pterygoid plate fracture pattern or incidence. Nevertheless, understanding the etiology of pterygoid plate fracture may help decrease the occurrence of neurological-ophthalmologic complications and their associated morbidities. e-62
Orthognathic Surgery Simulation Using Cadavers M. D. Walker: Hospital of the University of Pennsylvania, J. Chou, D. C. Stanton Historically, clinical training in orthognathic surgery for oral surgery residents has been gained through performing surgery on actual patients in the operating room. On the job training for these specialized surgical techniques has the potential for leading to less than ideal AAOMS 2013
R
L
35.1 11.2 9.0 3.7 7.5 31.2 100.6 211.7 352.5 486.7 735.7
34.9 11.3 8.8 4.0 7.0 31.4 94.3 205.3 252.2 508.7 729.7
Table II Anatomical mean values of non-fracture population Reference Points Piriform-Base Line Lateral Plate Medial Plate A-P Thickness PMJ M-L Thickness PMJ Lateral Wall-PMJ Angle of PMJ Area of Lateral Wall (mm2) HU PMJ HU Zygomatic Buttress HU Piriform
R
L
34.8 12.2 9.0 5.0 7.2 31.2 99.9 208.1 311.9 491.3 713.8
34.6 11.8 9.5 4.3 6.8 30.9 96.1 204.5 277.7 438.1 723.9
References: 1. Precious DS: Pterygoid Plate Fracture in Le Fort 1 Osteotomy With and Without Pterygoid Chisel: A Computer Tomography Scan Evaluation of 58 Patients. J Oral Maxillofacial Surgery 51:151-153, 1993 2. Fonseca RJ: Oral and Maxillofacial Surgery. Volume 2:232-248.
POSTER 38 Orthognathic Surgery in the Mobius Syndrome Patient R. M. Ulma: University of California, Los Angeles, School of Dentistry, S. L. Ratner, M. Wilson Mobius syndrome has been well described in the literature since von Graffe’s seminal report in 1880. It is defined by the congenital, non-progressive palsy of the sixth and seventh cranial nerves, with occasional involvement of other cranial nerves. Facial and abducens nerve involvement can be unilateral or bilateral, and paralysis can be partial or complete. The incidence of Mobius syndrome has not been determined, although it is estimated to occur in 1:50,000 live births, with an equal gender distribution. The pathophysiology of Mobius syndrome is not completely understood. It is attributed to brainstem dysfunction, caused by agenesis of the involved cranial nerve nuclei, prompted by either environmental or genetic causes. Despite its rarity, the dental and maxillofacial management of the Mobius patient warrants attention. The management of soft tissue manifestations in these patients, particularly treatment of facial muscle paralysis, is well described. The treatment of other common maxillofacial abnormalities, however, has not been studied as extensively. A recent search of the literature on the hard tissue management of Mobius patients afforded only three case reports on a total of four patients. Three patients who underwent dentofacial deformity correction with orthognathic surgery are presented. This is the largest case series on orthognathic surgery in the Mobius syndrome patient, performed at one institution by one surgeon. Common dental and maxillofacial features of the Mobius patient and pertinent surgical treatment planning recommendations are also discussed.
POSTER 39 The incidence of untoward pterygoid plate fracture has been reported to be as high as 87%.1 Pterygoid plate fracture happens nearly 50% of the time and 17% were high-level fractures. Based on our data, neither surgical technique nor anatomical variability played a significant contributing role to pterygoid plate fracture pattern or incidence. Nevertheless, understanding the etiology of pterygoid plate fracture may help decrease the occurrence of neurological-ophthalmologic complications and their associated morbidities. e-62
Orthognathic Surgery Simulation Using Cadavers M. D. Walker: Hospital of the University of Pennsylvania, J. Chou, D. C. Stanton Historically, clinical training in orthognathic surgery for oral surgery residents has been gained through performing surgery on actual patients in the operating room. On the job training for these specialized surgical techniques has the potential for leading to less than ideal AAOMS 2013