- Email: [email protected]
Condylectomy or IVRO: Surgical technique for condylar hyperplasia
025A - Orthognathic, cleft lip~palate and craniofacial surgery airway spaces following mandibular setback surgery was found. The upper and lower tongue was posteriorly repositioned immediately after surgery. During follow-up period, the hypopharyngeal airway space and lower tongue posture returned to the preoperative positions, but the oropharyngeal airway space and upper tongue posture were not significantly changed. The position of pogonion remarkably changed to backward immediately after surgery, but slightly anterior advancement was found during follow-up period. Conclusion Immediately after mandibular setback surgery, the oropharyngeal and hypopharyngeaI airway spaces obviously decreased due to posterior and inferior repositions of the tongue and hyoid bone. During follow-up period, lower tongue and hyoid bone returned to the preoperative positions, it was related to advancement of the pogonion in this period. The narrowing of the oropharyngeal airway space and posterior movement of the upper tongue posture were permanent after mandibular setback surgery. We suspect this phenomenon had influence on maintaining the total volume of oral cavity against mandibular setback.
12. New Methods of "Intraoral Le Fort III Osteotomies" for Midfacial Correction: The Rationale and Various Techniques
Choung, P. Department of Oral and maxillofacial Surgery, College of Dentistry, Seoul National University, Seoul, Korea In the midfacial deformity involved naso-maxillary-zygoma area, Le Fort III osteotomy is indicated. Traditional approaches to Le Fort III osteotomy are all extraoral incisions. So far, there has not been an intraoral approach to Le Fort III osteotomy developed. Correction of midfacial deformity should be performed according to individual deformity. Therefore, each anatomical component of the midface such as nose, maxilla, infraorbital rim, zygoma and zygomatic arch area should be corrected individually. So individual osteotomy of each component of the midface is needed and essential to solve problems of the one-piece design of Le Fort III. Six types of Le Fort III osteotomies via an intraoral approach were developed according to the individual deformity.
11
Among 33 cases of intraoral Le Fort III and II osteotomies, six types of intraoral approaches of Le Fort III osteotomies were 13 cases. They were carried out successfully via an intraoral approach with good results. There have not been complications. Six types of "Intraoral Le Fort III osteotomies" can be applied to the individual deformity via an intraoral approach using individual osteotomy of each anatomical component of the midface.
13. Reverse Step Le Fort 10steotomy
Davis, B., Precious, D. Dalhousie University and Queen Elizabeth H Health Sciences Centre, Halifax, Nova Scotia, Canada Problem One common orthognathic surgical requirement for patients with cleft lip/palate is maxillary advancement. Conventional LeFort I step osteotomy prevents unwanted movements associated with "ramping" but the step actually opens a bony gap equal in size to that of the required advancement. Technique An osteotomy design which is stepped superiorly in the posterior maxilla is presented. The osteotomy design permits placement of the anterior miniplate in a relatively low position thus avoiding postoperative patient complaints of being able to feel the plate. Experience This design has been used in 46 cleft lip/palate patients and more than 600 non-cleft patients. It has given good intraoperative spatial oriex~tation, a type of boy overlap rather than defect in maxillary advancement, good suitability to accept bone grafts, low incidence of comminution of the posterior maxillary wall and increased ease of performing concomitant muscle surgery of the upper lip. The safety of this procedure has been examined both clinically and with the use of CT scans.
14. Condylectomy or IVRO: Surgical Techniques for Condylar Hyperplasia
Hong, S., Baik, S., Park, J., Park, H., Yi, C. 1. Type I (Intraoral Le Fort III): Nose + Maxilla + Zygoma - Zygomatic a r c h - Infraorbital rim. 2. Type I I (Intraoral Wide Le Fort III): Nose + Maxilla + Zygoma + Zygomatic arch - Infraorbital rim. 3. Type III (Intraoral High Le Fort III): Nose + Maxilla + Zygoma + Infraorbital rim - Zygomatic arch. 4. Type IV (Intraoral High and Wide Le Fort III): Nose + Maxilla + Zygoma + Zygomatic arch + Infraorbital rim. 5. Type V (Intraoral Modified Le Fort III): Maxilla + Zygoma + Infraorbital rim - Zygomatic arch - Nose. 6. Type VI (Intraoral Modified Low Le Fort III): Maxilla + Zygoma + Zygomatic arch - Infraorbital rim - Nose.
Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University, Seoul, Korea
Although condylar hyperplasia has been treated for several decades, the adequate surgical techniques according to the type of condylar hyperplasia are still controversial. We studied 30 cases of condylar hyperplasia which had been treated with several surgical techniques. Among the 30 patients, 5 active unilateral condylar hyperplasia were treated b y a high condylectomy alone, 10 inactive
12
025A - Orthognathic, cleft lip~palate and craniofacial surgery
condylar hyperplasia by an orthognathic surgery (Le Fort I Bi-condylectomy) with orthodontic treatment, and another 15 inactive condylar hyperplasia by an orthognathic surgery (Le Fort I+IVRO) with orthodontic treatment. We observed long term postoperative functional remodeling of facial skeletons in a high condylectomy alone group for 2 years. Postoperative results between Le Fort I/Bi-condylectomy group and Le Fort I/IVRO group were compared by means of Delaire's cephalometric analysis. The results of our investigation were as follows: 1. Facial asymmetry was improved and favorable occlusion was obtained without any orthodontic intervention in unilateral high condylectomy alone group. 2. Both orthognatbic surgery groups (Bi-condylectomy, IVRO) showed favorable postoperative stability except for one Bi-condylectomy case (open-bite tendency). Conclusion Active condylar hyperplasia can be corrected by high condylectomy alone. Both IVRO and Bi-condylectomy are appropriate surgical techniques, but IVRO seems to be a better indication in an inactive condylar hyperplasia.
15. The Vector of Growth During Mandibular Distraction with Intraoral Devices
Karakasis, D. Department of Oral and Maxillofacial Surgery, Aristotle University, Thessalonikg Greece Intraoral distractors, as they are attached to the surface of the mandible, have a more or less certain defined plane for placement. The vector of growth is placed to the desired direction parallel to the surface of the mandible. This vector does not remain constant during the distraction period but its direction is changing. The problem of predictability of the final result is related to these changes. Placing the distractor, the surgeon should anticipate the changes of the vector of growth. These changes are demonstrated in the clinical material of our cases treated in the last three years. It seems that the changes of the vector of growth are due to the differences of resilience between the surrounding soft tissues but also they are due to the interaction between distraction forces if more than one distractor has been used.
16. A Prospective Study on the Selection of Surgical Techniques According to the Type of Skeletal Open-Bite
Kim, B., Balk, S., Park, J., Park, H., Yi, C. Department of Oral and Maxillofacial Surgery, Yonsei University, Seoul, Korea There is a plethora of surgical techniques to correct skeletal open-bite, yet the incidence of relapse is still high. This means that the decisive point in managing skeletal open-bite is not so much surgical technique itself but rather a careful diagnostic evaluation to make a selection of the appropriate surgical technique. We classified the type of skeletal open-bite based on the architectural and structural craniofacial cephalometric analysis as foilows: 1. excessive rotational growth of maxilla, 2. deficient vertical growth of anterior maxilla, 3. excessive mandibular angle, and 4. deficient vertical growth of mandibular ramus. The following surgical techniques were used according to the type of skeletal open-bite: posterior impaction of maxilla, anterior down repositioning of maxilla, sagittal split horizontal ramus osteotomy of mandible, and extraoral vertical ramus osteotomy of mandible. We evaluated the postoperative stability and relapse of 30 skeletal open-bite patients who had been operated on from 1995 to 1997 and followed up for 6 months. The following results were obtained: 1. 28 cases among 30 skeletal open-bite cases were corrected by proper surgical techniques selected according to the type of etiologic factors and favorable postoperative stability was observed without a skeletal relapse. 2. One of 2 relapse cases relapsed due to surgical error and the other due to the improper selection of surgical technique. The selection of appropriate surgical techniques according to the type of skeletal open-bite is considered to be important for postoperative stability without a relapse.
17. Self-Reinforced P(L/DL)LA Osteosynthesis with Bimaxillary Surgery: A Prospective Study of MaterialRelated Failures and Skeletal Stability
Haers, R, Sailer, H. Department of Cranio-Maxillofacial Surgery, University Hospital Zurich, Zurich, Switzerland Statement of the problem Metal/titanium osteosynthesis has disadvantages such as corrosion, interference with modern imaging techniques and the deed of a second intervention if the material has to be removed. This can be overcome with biodegradable material. This study presents the incidence of material related failures and the skeletal stability pattern one year postoperatively when using self-reinforced poly (L/DL) lactide copolymer (70/30) in bimaxillary procedures.
12. New Methods of "Intraoral Le Fort III Osteotomies" for Midfacial Correction: The Rationale and Various Techniques
Choung, P. Department of Oral and maxillofacial Surgery, College of Dentistry, Seoul National University, Seoul, Korea In the midfacial deformity involved naso-maxillary-zygoma area, Le Fort III osteotomy is indicated. Traditional approaches to Le Fort III osteotomy are all extraoral incisions. So far, there has not been an intraoral approach to Le Fort III osteotomy developed. Correction of midfacial deformity should be performed according to individual deformity. Therefore, each anatomical component of the midface such as nose, maxilla, infraorbital rim, zygoma and zygomatic arch area should be corrected individually. So individual osteotomy of each component of the midface is needed and essential to solve problems of the one-piece design of Le Fort III. Six types of Le Fort III osteotomies via an intraoral approach were developed according to the individual deformity.
11
Among 33 cases of intraoral Le Fort III and II osteotomies, six types of intraoral approaches of Le Fort III osteotomies were 13 cases. They were carried out successfully via an intraoral approach with good results. There have not been complications. Six types of "Intraoral Le Fort III osteotomies" can be applied to the individual deformity via an intraoral approach using individual osteotomy of each anatomical component of the midface.
13. Reverse Step Le Fort 10steotomy
Davis, B., Precious, D. Dalhousie University and Queen Elizabeth H Health Sciences Centre, Halifax, Nova Scotia, Canada Problem One common orthognathic surgical requirement for patients with cleft lip/palate is maxillary advancement. Conventional LeFort I step osteotomy prevents unwanted movements associated with "ramping" but the step actually opens a bony gap equal in size to that of the required advancement. Technique An osteotomy design which is stepped superiorly in the posterior maxilla is presented. The osteotomy design permits placement of the anterior miniplate in a relatively low position thus avoiding postoperative patient complaints of being able to feel the plate. Experience This design has been used in 46 cleft lip/palate patients and more than 600 non-cleft patients. It has given good intraoperative spatial oriex~tation, a type of boy overlap rather than defect in maxillary advancement, good suitability to accept bone grafts, low incidence of comminution of the posterior maxillary wall and increased ease of performing concomitant muscle surgery of the upper lip. The safety of this procedure has been examined both clinically and with the use of CT scans.
14. Condylectomy or IVRO: Surgical Techniques for Condylar Hyperplasia
Hong, S., Baik, S., Park, J., Park, H., Yi, C. 1. Type I (Intraoral Le Fort III): Nose + Maxilla + Zygoma - Zygomatic a r c h - Infraorbital rim. 2. Type I I (Intraoral Wide Le Fort III): Nose + Maxilla + Zygoma + Zygomatic arch - Infraorbital rim. 3. Type III (Intraoral High Le Fort III): Nose + Maxilla + Zygoma + Infraorbital rim - Zygomatic arch. 4. Type IV (Intraoral High and Wide Le Fort III): Nose + Maxilla + Zygoma + Zygomatic arch + Infraorbital rim. 5. Type V (Intraoral Modified Le Fort III): Maxilla + Zygoma + Infraorbital rim - Zygomatic arch - Nose. 6. Type VI (Intraoral Modified Low Le Fort III): Maxilla + Zygoma + Zygomatic arch - Infraorbital rim - Nose.
Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University, Seoul, Korea
Although condylar hyperplasia has been treated for several decades, the adequate surgical techniques according to the type of condylar hyperplasia are still controversial. We studied 30 cases of condylar hyperplasia which had been treated with several surgical techniques. Among the 30 patients, 5 active unilateral condylar hyperplasia were treated b y a high condylectomy alone, 10 inactive
12
025A - Orthognathic, cleft lip~palate and craniofacial surgery
condylar hyperplasia by an orthognathic surgery (Le Fort I Bi-condylectomy) with orthodontic treatment, and another 15 inactive condylar hyperplasia by an orthognathic surgery (Le Fort I+IVRO) with orthodontic treatment. We observed long term postoperative functional remodeling of facial skeletons in a high condylectomy alone group for 2 years. Postoperative results between Le Fort I/Bi-condylectomy group and Le Fort I/IVRO group were compared by means of Delaire's cephalometric analysis. The results of our investigation were as follows: 1. Facial asymmetry was improved and favorable occlusion was obtained without any orthodontic intervention in unilateral high condylectomy alone group. 2. Both orthognatbic surgery groups (Bi-condylectomy, IVRO) showed favorable postoperative stability except for one Bi-condylectomy case (open-bite tendency). Conclusion Active condylar hyperplasia can be corrected by high condylectomy alone. Both IVRO and Bi-condylectomy are appropriate surgical techniques, but IVRO seems to be a better indication in an inactive condylar hyperplasia.
15. The Vector of Growth During Mandibular Distraction with Intraoral Devices
Karakasis, D. Department of Oral and Maxillofacial Surgery, Aristotle University, Thessalonikg Greece Intraoral distractors, as they are attached to the surface of the mandible, have a more or less certain defined plane for placement. The vector of growth is placed to the desired direction parallel to the surface of the mandible. This vector does not remain constant during the distraction period but its direction is changing. The problem of predictability of the final result is related to these changes. Placing the distractor, the surgeon should anticipate the changes of the vector of growth. These changes are demonstrated in the clinical material of our cases treated in the last three years. It seems that the changes of the vector of growth are due to the differences of resilience between the surrounding soft tissues but also they are due to the interaction between distraction forces if more than one distractor has been used.
16. A Prospective Study on the Selection of Surgical Techniques According to the Type of Skeletal Open-Bite
Kim, B., Balk, S., Park, J., Park, H., Yi, C. Department of Oral and Maxillofacial Surgery, Yonsei University, Seoul, Korea There is a plethora of surgical techniques to correct skeletal open-bite, yet the incidence of relapse is still high. This means that the decisive point in managing skeletal open-bite is not so much surgical technique itself but rather a careful diagnostic evaluation to make a selection of the appropriate surgical technique. We classified the type of skeletal open-bite based on the architectural and structural craniofacial cephalometric analysis as foilows: 1. excessive rotational growth of maxilla, 2. deficient vertical growth of anterior maxilla, 3. excessive mandibular angle, and 4. deficient vertical growth of mandibular ramus. The following surgical techniques were used according to the type of skeletal open-bite: posterior impaction of maxilla, anterior down repositioning of maxilla, sagittal split horizontal ramus osteotomy of mandible, and extraoral vertical ramus osteotomy of mandible. We evaluated the postoperative stability and relapse of 30 skeletal open-bite patients who had been operated on from 1995 to 1997 and followed up for 6 months. The following results were obtained: 1. 28 cases among 30 skeletal open-bite cases were corrected by proper surgical techniques selected according to the type of etiologic factors and favorable postoperative stability was observed without a skeletal relapse. 2. One of 2 relapse cases relapsed due to surgical error and the other due to the improper selection of surgical technique. The selection of appropriate surgical techniques according to the type of skeletal open-bite is considered to be important for postoperative stability without a relapse.
17. Self-Reinforced P(L/DL)LA Osteosynthesis with Bimaxillary Surgery: A Prospective Study of MaterialRelated Failures and Skeletal Stability
Haers, R, Sailer, H. Department of Cranio-Maxillofacial Surgery, University Hospital Zurich, Zurich, Switzerland Statement of the problem Metal/titanium osteosynthesis has disadvantages such as corrosion, interference with modern imaging techniques and the deed of a second intervention if the material has to be removed. This can be overcome with biodegradable material. This study presents the incidence of material related failures and the skeletal stability pattern one year postoperatively when using self-reinforced poly (L/DL) lactide copolymer (70/30) in bimaxillary procedures.