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A transoral approach for threedimensional repositioning of the proximal segment after mandibular sagittal split ramus osteotomy
1256
TRANSORAL
METHOD
FOR THREE-DIMENSIONAL
REPOSITIONING
J Oral Maxillofac Surg 54:1256-1258, 1996
A Transoral Approach for ThreeDimensional Repositioning of the Proximal Segment After mandibular Sagittal Split Ramus Osteotomy KIMITOSHI
YAGAMI,
DDS, PHD,” AND MASAO
Maintenance of the presurgical position of the proximal segment is extremely important after a sagittal split ramus osteotomy (SSRO) to reduce the incidence of short-term relapse or temporomandibul~ joint dysfunction, particularly when rigid fixation is used.‘” The use of numerous techniques and devices has been proposed to solve the problem of condylar repositioning.4-” In 1985, Luhr’ described the positioning plate technique for the repositioning of the proximal segment. This system was the first to afford the accurate repositioning of the proximal segment in three dimensions.8 Several additional three-dimensional techniques of repositioning the proximal segment have been reported in the past 10 years, but all of them require skin in~isions.s,9,‘1 We have recently developed a transoral approach for placement of the positioning plate in repositioning of the proximal segment. In this report, we introduce this repositioning system and technique.
NAGUMO,
DDS, PHDt
positioning plate system composed of a T-shaped plate, acrylic block, and screws with hexagonal heads (Leibinger, Germany). Before the operation, the arch bar is adjusted so that it fits the maxillary dental arch and buccal tubes on the upper molars (usually the first molars). Acrylic blocks (5 X 10 X 2 mm) are attached to the arch bar at the location adjacent to the buccal tubes. Operations Osteotomy is perfo~ed splitting of the mandible,
in the usual manner. Before an acrylic block is secured
Technique PREPARATION OF THE REPOSITIONING
SYSTEM
The system consists of the four components (Fig 1): a splint that guides the distal segment to the planned occlusion (occlusal splint), a splint that reproduces the preoperative centric relation (centric splint), a modified ready-made arch bar (Tomy Int. Co, Japan), and a Received from the Second Department of Oral and Maxillofacial Surgery, School of Dentistry, Showa University, Tokyo, Japan. * Assistant professor. Second Department of Oral and Maxillofacial Surgery, School of Dentistry, Showa University, Tokyo, Japan. 7 Professor and Chairman. Second Dep~ment of Oral and Maxillofacial Surgery, School of Dentistry, Showa University, Tokyo, Japan. Address correspondence and reprint requests to Dr Yagami: Second Department of Oral and Maxillofacial Surgery, Showa University Dental HospitaI, 2-l-l ~tasenzoku, Ohta-ku, Tokyo, 145 Japan. 0 1996 American
Association
0278-2391/96/541
O-001 8$3.00/O
of Oral and Maxillofacial
Surgeons
FIGURE 1. The re~sitio~ng system consists of an occlusal splint (a), a centric occlusion splint (b), an arch bar with acrylic btocks (c), and a positioning plate system composed of screws (d), an acrylic block (e), and a positioning plate (f).
YAGAMI
AND
1257
NAGUMO
to the stem of a T-shaped plate with the aid of two screws, and the positioning plate with acrylic block is bent and applied to the lingual surface of the ramus at the level of the maxillary teeth with the two bone screws (Fig 2). Maxillomandibular fixation (MMF) is then established after placement of the teeth in preoperative centric relation with the centric splint. The arch bar is inserted in the buccal tubes, and the space between the acrylic block on the T-shaped plate and the acrylic block on the arch bar is filled with self-curing resin (Fig 3). The procedure is repeated on the other side, and the presurgical position of the condyle and proximal segment is now registered in three dimensions. Special care is taken that the acrylic blocks do not contact directly with the metal plates and orthodontic appliances, because direct contact can cause the distortion of the positioning plates. After removal of the anterior plate screws and the arch bar, the MMF is released, and the sagittal split is performed. The positioning plates are usually left attached to the rami while the split is completed. The distal segment is then moved into the planned position
FIGURE 3. Registration of the position of the mandibular condyle. The mandible is placed in proper occlusion using the centric selection splint. The space between the acrylic block on the arch bar and the acrylic block on the positioning plate is filled with self-curing resin.
by using the occlusal splint. The MMF is reapplied, the arch bar is reinserted, and the proximal segments are repositioned by fixing the acrylic block on the arch bar to the acrylic block on the metal plate with the original screws. If the split segments interfere with each other, the interfering portion of bone is removed. Finally, the proximal and distal segments are fixed transorally, each with a four-hole miniplate and an additional position screw. Discussion
FIGURE 2. The positioning plate with its acrylic block is applied to the lingual surface of the ramus at the level of the maxillary teeth with screws before the sagittal split.
The main problem with rigid fixation in the SSRO is the difficulty of maintaining the presurgical position of the mandibular condyles. Although this problem applies also to internal wiring of osteotomized segments, 7 it is more critical when rigid fixation with screws or plates is used.12 Failure to correctly reposition the proximal segment can result in short-term relapse or temporomandibular joint dysfunction.‘” The main disadvantage of our repositioning system is that it requires a certain degree of experience and skill. However, the technique has been used successfully in more than 20 cases without any trouble. Another disadvantage is that it is difficult to apply this technique when significant asymmetrical shifting of the distal segment is performed, although this is also the case with other three-dimensional repositioning systems. In this event, we use a conventional repositioning technique in which the distance from the upper canine to a reference hole on the anterior lateral cortex of the mandibular ramus is marked with a wire. Finally, our repositioning technique has the major
1258 advantage of obviating skin ity of scarring and damage important with the SSRO, improvement and cosmetic
TRANSORAL
incisions with the possibilto the facial nerve. This is in which both functional must be considered.
METHOD
6.
7.
References 8. 1. Kundert M, Hadjianghelou 0: Condylar displacement after sagittal splitting of the mandibular rami. .I Maxillofac Surg 8:278, 1980 2. Epker BN, Wessberg GA: Mechanisms of early skeletal relapse following surgical advancement of the mandible. Br J Oral Surg 20:175, 1982 3. Van Sick& JE, Larsen AJ, Thrash WJ: Relapse after rigid fixation of mandibular advancement. J Oral Maxillofac Surg 44:698, 1986 4. Leonard MS: Preventing rotation of the proximal fragment in the sagittal ramus split operation. J Oral Surg 34:942, 1976 5. Leonard MS: Maintenance of condylar position after sagittal
9.
10.
11.
12.
FOR
THREE-DIMENSIONAL
REPOSITIONING
split osteotomy of the mandible. J Oral Maxillofac Surg 43:391, 1985 Luhr HG: Skelettverlagernde Operationen zur Harmonisierung des Gesichtsprofils-Probleme der stabilen,,,Fixation von Osteotomiesegmenten, in Pfeifer G (ed): Die Asthetik von Form und Funktion in der Plastischen und Wiederhersetel-lungschirurgie. Berlin, Springer-Verlag, 1985, pp 87-92 Epker BN, Wylie GA: Control of condylar-proximal mandibular segments after sagittal split osteotomies to advance the mandible. Oral Surg 62:613, 1986 Hiatt WR, Schelkun PM, Moore DL: Condylar positioning in orthognathic surgery. J Oral Maxillofac Surg 46: 1110, 1988 Raveh J, Vuillemin T, Ladrach K, et al: New techniques for reproduction of the condyle relation and reduction of complications after sagittal ramus split osteotomy of the mandible. J Oral Maxillofac Surg 46:751, 1988 Rotskoff KS. Herbosa EG, Villa P: Maintenance of condvleproximal segment position in orthognathic surgery. J &al Maxillofac Surg 462, 1991 Harada K, Okada Y, Nagura H: A new repositioning system for the proximal segment in sagittal split ramus osteotomy of the mandible. Int J-Oral Maxifiofac Surg 23:71, 1994 Luhr HG: The significance of condylar position using rigid fixation in orthognathic surgery. Clin Plast Surg 16:147, 1989
TRANSORAL
METHOD
FOR THREE-DIMENSIONAL
REPOSITIONING
J Oral Maxillofac Surg 54:1256-1258, 1996
A Transoral Approach for ThreeDimensional Repositioning of the Proximal Segment After mandibular Sagittal Split Ramus Osteotomy KIMITOSHI
YAGAMI,
DDS, PHD,” AND MASAO
Maintenance of the presurgical position of the proximal segment is extremely important after a sagittal split ramus osteotomy (SSRO) to reduce the incidence of short-term relapse or temporomandibul~ joint dysfunction, particularly when rigid fixation is used.‘” The use of numerous techniques and devices has been proposed to solve the problem of condylar repositioning.4-” In 1985, Luhr’ described the positioning plate technique for the repositioning of the proximal segment. This system was the first to afford the accurate repositioning of the proximal segment in three dimensions.8 Several additional three-dimensional techniques of repositioning the proximal segment have been reported in the past 10 years, but all of them require skin in~isions.s,9,‘1 We have recently developed a transoral approach for placement of the positioning plate in repositioning of the proximal segment. In this report, we introduce this repositioning system and technique.
NAGUMO,
DDS, PHDt
positioning plate system composed of a T-shaped plate, acrylic block, and screws with hexagonal heads (Leibinger, Germany). Before the operation, the arch bar is adjusted so that it fits the maxillary dental arch and buccal tubes on the upper molars (usually the first molars). Acrylic blocks (5 X 10 X 2 mm) are attached to the arch bar at the location adjacent to the buccal tubes. Operations Osteotomy is perfo~ed splitting of the mandible,
in the usual manner. Before an acrylic block is secured
Technique PREPARATION OF THE REPOSITIONING
SYSTEM
The system consists of the four components (Fig 1): a splint that guides the distal segment to the planned occlusion (occlusal splint), a splint that reproduces the preoperative centric relation (centric splint), a modified ready-made arch bar (Tomy Int. Co, Japan), and a Received from the Second Department of Oral and Maxillofacial Surgery, School of Dentistry, Showa University, Tokyo, Japan. * Assistant professor. Second Department of Oral and Maxillofacial Surgery, School of Dentistry, Showa University, Tokyo, Japan. 7 Professor and Chairman. Second Dep~ment of Oral and Maxillofacial Surgery, School of Dentistry, Showa University, Tokyo, Japan. Address correspondence and reprint requests to Dr Yagami: Second Department of Oral and Maxillofacial Surgery, Showa University Dental HospitaI, 2-l-l ~tasenzoku, Ohta-ku, Tokyo, 145 Japan. 0 1996 American
Association
0278-2391/96/541
O-001 8$3.00/O
of Oral and Maxillofacial
Surgeons
FIGURE 1. The re~sitio~ng system consists of an occlusal splint (a), a centric occlusion splint (b), an arch bar with acrylic btocks (c), and a positioning plate system composed of screws (d), an acrylic block (e), and a positioning plate (f).
YAGAMI
AND
1257
NAGUMO
to the stem of a T-shaped plate with the aid of two screws, and the positioning plate with acrylic block is bent and applied to the lingual surface of the ramus at the level of the maxillary teeth with the two bone screws (Fig 2). Maxillomandibular fixation (MMF) is then established after placement of the teeth in preoperative centric relation with the centric splint. The arch bar is inserted in the buccal tubes, and the space between the acrylic block on the T-shaped plate and the acrylic block on the arch bar is filled with self-curing resin (Fig 3). The procedure is repeated on the other side, and the presurgical position of the condyle and proximal segment is now registered in three dimensions. Special care is taken that the acrylic blocks do not contact directly with the metal plates and orthodontic appliances, because direct contact can cause the distortion of the positioning plates. After removal of the anterior plate screws and the arch bar, the MMF is released, and the sagittal split is performed. The positioning plates are usually left attached to the rami while the split is completed. The distal segment is then moved into the planned position
FIGURE 3. Registration of the position of the mandibular condyle. The mandible is placed in proper occlusion using the centric selection splint. The space between the acrylic block on the arch bar and the acrylic block on the positioning plate is filled with self-curing resin.
by using the occlusal splint. The MMF is reapplied, the arch bar is reinserted, and the proximal segments are repositioned by fixing the acrylic block on the arch bar to the acrylic block on the metal plate with the original screws. If the split segments interfere with each other, the interfering portion of bone is removed. Finally, the proximal and distal segments are fixed transorally, each with a four-hole miniplate and an additional position screw. Discussion
FIGURE 2. The positioning plate with its acrylic block is applied to the lingual surface of the ramus at the level of the maxillary teeth with screws before the sagittal split.
The main problem with rigid fixation in the SSRO is the difficulty of maintaining the presurgical position of the mandibular condyles. Although this problem applies also to internal wiring of osteotomized segments, 7 it is more critical when rigid fixation with screws or plates is used.12 Failure to correctly reposition the proximal segment can result in short-term relapse or temporomandibular joint dysfunction.‘” The main disadvantage of our repositioning system is that it requires a certain degree of experience and skill. However, the technique has been used successfully in more than 20 cases without any trouble. Another disadvantage is that it is difficult to apply this technique when significant asymmetrical shifting of the distal segment is performed, although this is also the case with other three-dimensional repositioning systems. In this event, we use a conventional repositioning technique in which the distance from the upper canine to a reference hole on the anterior lateral cortex of the mandibular ramus is marked with a wire. Finally, our repositioning technique has the major
1258 advantage of obviating skin ity of scarring and damage important with the SSRO, improvement and cosmetic
TRANSORAL
incisions with the possibilto the facial nerve. This is in which both functional must be considered.
METHOD
6.
7.
References 8. 1. Kundert M, Hadjianghelou 0: Condylar displacement after sagittal splitting of the mandibular rami. .I Maxillofac Surg 8:278, 1980 2. Epker BN, Wessberg GA: Mechanisms of early skeletal relapse following surgical advancement of the mandible. Br J Oral Surg 20:175, 1982 3. Van Sick& JE, Larsen AJ, Thrash WJ: Relapse after rigid fixation of mandibular advancement. J Oral Maxillofac Surg 44:698, 1986 4. Leonard MS: Preventing rotation of the proximal fragment in the sagittal ramus split operation. J Oral Surg 34:942, 1976 5. Leonard MS: Maintenance of condylar position after sagittal
9.
10.
11.
12.
FOR
THREE-DIMENSIONAL
REPOSITIONING
split osteotomy of the mandible. J Oral Maxillofac Surg 43:391, 1985 Luhr HG: Skelettverlagernde Operationen zur Harmonisierung des Gesichtsprofils-Probleme der stabilen,,,Fixation von Osteotomiesegmenten, in Pfeifer G (ed): Die Asthetik von Form und Funktion in der Plastischen und Wiederhersetel-lungschirurgie. Berlin, Springer-Verlag, 1985, pp 87-92 Epker BN, Wylie GA: Control of condylar-proximal mandibular segments after sagittal split osteotomies to advance the mandible. Oral Surg 62:613, 1986 Hiatt WR, Schelkun PM, Moore DL: Condylar positioning in orthognathic surgery. J Oral Maxillofac Surg 46: 1110, 1988 Raveh J, Vuillemin T, Ladrach K, et al: New techniques for reproduction of the condyle relation and reduction of complications after sagittal ramus split osteotomy of the mandible. J Oral Maxillofac Surg 46:751, 1988 Rotskoff KS. Herbosa EG, Villa P: Maintenance of condvleproximal segment position in orthognathic surgery. J &al Maxillofac Surg 462, 1991 Harada K, Okada Y, Nagura H: A new repositioning system for the proximal segment in sagittal split ramus osteotomy of the mandible. Int J-Oral Maxifiofac Surg 23:71, 1994 Luhr HG: The significance of condylar position using rigid fixation in orthognathic surgery. Clin Plast Surg 16:147, 1989