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Technical Modification Designed to Facilitate Sagittal Split Ramus Osteotomy
J Oral Maxillofac Surg 66:1542-1544, 2008
Technical Modification Designed to Facilitate Sagittal Split Ramus Osteotomy Toshitaka Muto, DDS, PhD,* Kazuki Akizuki, DDS, PhD,† and Yasuto Tsuchida, DDS‡ The mandibular sagittal split ramus osteotomy (SSRO) was first described by Trauner and Obwegeser in 1957.1 Since then, numerous modifications have been developed, including those described by Hunsuck,2 Epker,3 and Wolford et al.4 SSRO has been shown to be a safe technique with a stable outcome and very few serious complications.5,6 The most common complication of SSRO is neurosensory deficit affecting the inferior alveolar nerve (IAN).5 Damage to the IAN may be caused by several factors, including splitting of bone during the operation.7 Various techniques and instruments for splitting the ramus have been proposed to minimize the risk of damaging the IAN.3,4,8,9 To avoid complications, we have used a specially designed bone cleaver to perform SSRO in more than 100 patients with mandibular prognathism. Good outcomes were obtained in all patients, with no complications, such as damage to the IAN. This report describes this alternative technique.
The buccal osteotomy is directed from the second molar region to the mandibular angle. The 2 osteotomies are then connected (Fig 1). At the same time, both the superior buccal cortical edges (inner corner of the proximal segment and outer corner of the distal segment) are removed to facilitate insertion of the specially designed bone cleaver (Fig 2). The bone cleaver with a guide is inserted into the anterior superior corner of the proximal segment (Figs 3, 4). With the buccal cortex of the distal segment serving as a fulcrum, the bone cleaver is rotated to promote splitting (Fig 5). The bone cleaver is malleted, with the guide of the bone cleaver placed along the anterior border of the proximal segment while maintaining the fulcrum of the buccal cortex of the distal segment, thereby applying force against the inner surface of the proximal segment. As the proximal and distal segments separate, suction is applied to the
Technique SSRO is performed to correct mandibular prognathism. On the lingual side of the ramus, a full-thickness mucoperiosteal flap is elevated lingually to identify the lingula. A periosteal elevator is used to retract the IAN and artery. A horizontal cut is made in the lingual aspect of the ramus, approximately 4 to 5 mm above the lingula and parallel to the occlusal surface of the teeth. The cut is made through the cortical bone and extended into the medullary bone, using a Lindeman bur with copious irrigation.
*Professor, Department of Oral and Maxillofacial Surgery, National Defense Medical College, Saitama, Japan. †Director, Division of Oral Surgery, Matsuda Orthopedic Hospital, Hokkaido, Japan. ‡Private Practice, Sapporo, Japan. Address correspondence and reprint requests to Dr Muto: Department of Oral & Maxillofacial Surgery, National Defense Medical College, Saitama, 359-8513, Japan; e-mail: [email protected] © 2008 American Association of Oral and Maxillofacial Surgeons
0278-2391/08/6607-0038$34.00/0 doi:10.1016/j.joms.2007.11.017
FIGURE 1. Medial osteotomy and buccal osteotomy are connected with a #703 tapered fissure bur. Muto et al. Technical Modification to Sagittal Split Ramus Osteotomy. J Oral Maxillofac Surg 2008.
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plane of cleavage, with close attention given to the IAN. In nearly all cases the IAN is not encountered, because SSRO is not indicated in the absence of cancerous bone between the mandibular canal and buccal cortex. The bone cleaver is gradually advanced inferiorly until the inferior border of the mandible is reached. The IAN is not damaged because the proximal and distal segments separate, and the edge of the bone cleaver is advanced along the inner surface of the proximal cortex. The IAN and soft tissue are at minimal risk of injury because the bone cleaver has a guide to prevent slippage. Finally, the bone cleaver is rotated at the inferior border of the mandible to apply force against the inner surface of the proximal segment, with the buccal cortex of the distal segment acting as a fulcrum (Fig 6). The proximal segment is easily mobilized because the bone cleaver is only 20 mm wide. After the setback, 1 miniplate and 4 screws are applied to promote rigid osteosynthesis.
Discussion We have used the above-described technique in more than 100 patients, with no cases of unfavorable splitting. The bone cleaver is inserted at the superior corner of the buccal osteotomy and is levered against the distal segment to apply force against the inner surface of the proximal segment. Edging the cleaver along the anterior border of the proximal segment
FIGURE 3. A, Overall view of the specially designed bone cleaver. B, The bone cleaver has a guide at the center of the unilateral wide surface. Muto et al. Technical Modification to Sagittal Split Ramus Osteotomy. J Oral Maxillofac Surg 2008.
toward the lower border ensures that splitting occurs gradually. The specially designed bone cleaver with a guide is easily advanced inferiorly and protects against slippage. The bone cleaver is also used to edge along the inferior border while prying at the same
FIGURE 2. Both superior edges of the buccal osteotomy, the inner corner at the proximal segment, and the outer corner at the distal segment are removed to allow easy insertion of the specially designed bone cleaver.
FIGURE 4. The bone cleaver with guide is inserted into the anterior superior corner of the proximal segment.
Muto et al. Technical Modification to Sagittal Split Ramus Osteotomy. J Oral Maxillofac Surg 2008.
Muto et al. Technical Modification to Sagittal Split Ramus Osteotomy. J Oral Maxillofac Surg 2008.
1544
TECHNICAL MODIFICATION TO SAGITTAL SPLIT RAMUS OSTEOTOMY
time to complete the split, which is easily accomplished because the cleaver is only 20 mm wide. Keeping the cleaver away from the IAN during this maneuver avoids risk of injuring the nerve. Although the Dal-pont modification of the buccal osteotomy technique has been considered to provide a more stable outcome, it has certain disadvantages compared with osteotomy at the mandibular angle, including unfavorable splitting10 and increased risk of severing the neurovascular bundle.8 Our technique using the specially designed bone cleaver facilitates
FIGURE 6. The bone cleaver positioned at the inferior border of the mandible is rotated to apply force against the inner surface of the proximal segment, with the buccal cortex of the distal segment serving as a fulcrum. Muto et al. Technical Modification to Sagittal Split Ramus Osteotomy. J Oral Maxillofac Surg 2008.
splitting of the ramus without damaging the IAN or other soft tissues.
References
FIGURE 5. The bone cleaver is malleted and rotated to promote splitting, with the buccal cortex of the distal segment acting as a fulcrum. Muto et al. Technical Modification to Sagittal Split Ramus Osteotomy. J Oral Maxillofac Surg 2008.
1. Trauner R, Obwegeser H: The surgical correction of mandibular prognathism and retrognathia with consideration of genioplasty. Oral Surg Oral Med Oral Pathol 10:677, 1957 2. Hunsack EE: A modified intraoral sagittal splitting technique for correction of mandibular prognathism. J Oral Surg 26:250, 1968 3. Epker BN: Modification in the sagittal osteotomy of the mandible. J Oral Surg 35:157, 1977 4. Wolford LM, Bennette MA, Rafferty CG: Modification of the mandibular ramus sagittal split osteotomy. Oral Surg Oral Med Oral Pathol 64:146, 1987 5. Panula K, Finne K, Oikarinen K: Incidence of complications and problems related to orthognathic surgery: A review of 655 patients. J Oral Maxillofac Surg 59:1128, 2001 6. Van de P, Sterling PJW, Blijdorp PA, et al: Perioperative morbidity in maxillofacial orthopaedic surgery: A retrospective study. J Craniomaxillofac Surg 24:263, 1996 7. Panula K, Finne K, Oikarinen K: Neurosensory deficits after bilateral sagittal split ramus osteotomy of the mandible: Influence of soft tissue handling medial to the ascending ramus. Int J Oral Maxillofac Surg 33:543, 2004 8. Fun-Chee L: Technical modification of the sagittal split mandibular ramus osteotomy. Oral Surg Oral Med Oral Pathol 74:723, 1992 9. Tuevey TA: Intraoperative complications of the sagittal osteotomy of the mandibular ramus: Incidence and management. J Oral Maxillofac Surg 43:504, 1985 10. Wolford LM, Davis WM Jr: The mandibular inferior border split: A modification in the sagittal split osteotomy. J Oral Maxillofac Surg 48:92, 1990
Technical Modification Designed to Facilitate Sagittal Split Ramus Osteotomy Toshitaka Muto, DDS, PhD,* Kazuki Akizuki, DDS, PhD,† and Yasuto Tsuchida, DDS‡ The mandibular sagittal split ramus osteotomy (SSRO) was first described by Trauner and Obwegeser in 1957.1 Since then, numerous modifications have been developed, including those described by Hunsuck,2 Epker,3 and Wolford et al.4 SSRO has been shown to be a safe technique with a stable outcome and very few serious complications.5,6 The most common complication of SSRO is neurosensory deficit affecting the inferior alveolar nerve (IAN).5 Damage to the IAN may be caused by several factors, including splitting of bone during the operation.7 Various techniques and instruments for splitting the ramus have been proposed to minimize the risk of damaging the IAN.3,4,8,9 To avoid complications, we have used a specially designed bone cleaver to perform SSRO in more than 100 patients with mandibular prognathism. Good outcomes were obtained in all patients, with no complications, such as damage to the IAN. This report describes this alternative technique.
The buccal osteotomy is directed from the second molar region to the mandibular angle. The 2 osteotomies are then connected (Fig 1). At the same time, both the superior buccal cortical edges (inner corner of the proximal segment and outer corner of the distal segment) are removed to facilitate insertion of the specially designed bone cleaver (Fig 2). The bone cleaver with a guide is inserted into the anterior superior corner of the proximal segment (Figs 3, 4). With the buccal cortex of the distal segment serving as a fulcrum, the bone cleaver is rotated to promote splitting (Fig 5). The bone cleaver is malleted, with the guide of the bone cleaver placed along the anterior border of the proximal segment while maintaining the fulcrum of the buccal cortex of the distal segment, thereby applying force against the inner surface of the proximal segment. As the proximal and distal segments separate, suction is applied to the
Technique SSRO is performed to correct mandibular prognathism. On the lingual side of the ramus, a full-thickness mucoperiosteal flap is elevated lingually to identify the lingula. A periosteal elevator is used to retract the IAN and artery. A horizontal cut is made in the lingual aspect of the ramus, approximately 4 to 5 mm above the lingula and parallel to the occlusal surface of the teeth. The cut is made through the cortical bone and extended into the medullary bone, using a Lindeman bur with copious irrigation.
*Professor, Department of Oral and Maxillofacial Surgery, National Defense Medical College, Saitama, Japan. †Director, Division of Oral Surgery, Matsuda Orthopedic Hospital, Hokkaido, Japan. ‡Private Practice, Sapporo, Japan. Address correspondence and reprint requests to Dr Muto: Department of Oral & Maxillofacial Surgery, National Defense Medical College, Saitama, 359-8513, Japan; e-mail: [email protected] © 2008 American Association of Oral and Maxillofacial Surgeons
0278-2391/08/6607-0038$34.00/0 doi:10.1016/j.joms.2007.11.017
FIGURE 1. Medial osteotomy and buccal osteotomy are connected with a #703 tapered fissure bur. Muto et al. Technical Modification to Sagittal Split Ramus Osteotomy. J Oral Maxillofac Surg 2008.
1542
MUTO ET AL
1543
plane of cleavage, with close attention given to the IAN. In nearly all cases the IAN is not encountered, because SSRO is not indicated in the absence of cancerous bone between the mandibular canal and buccal cortex. The bone cleaver is gradually advanced inferiorly until the inferior border of the mandible is reached. The IAN is not damaged because the proximal and distal segments separate, and the edge of the bone cleaver is advanced along the inner surface of the proximal cortex. The IAN and soft tissue are at minimal risk of injury because the bone cleaver has a guide to prevent slippage. Finally, the bone cleaver is rotated at the inferior border of the mandible to apply force against the inner surface of the proximal segment, with the buccal cortex of the distal segment acting as a fulcrum (Fig 6). The proximal segment is easily mobilized because the bone cleaver is only 20 mm wide. After the setback, 1 miniplate and 4 screws are applied to promote rigid osteosynthesis.
Discussion We have used the above-described technique in more than 100 patients, with no cases of unfavorable splitting. The bone cleaver is inserted at the superior corner of the buccal osteotomy and is levered against the distal segment to apply force against the inner surface of the proximal segment. Edging the cleaver along the anterior border of the proximal segment
FIGURE 3. A, Overall view of the specially designed bone cleaver. B, The bone cleaver has a guide at the center of the unilateral wide surface. Muto et al. Technical Modification to Sagittal Split Ramus Osteotomy. J Oral Maxillofac Surg 2008.
toward the lower border ensures that splitting occurs gradually. The specially designed bone cleaver with a guide is easily advanced inferiorly and protects against slippage. The bone cleaver is also used to edge along the inferior border while prying at the same
FIGURE 2. Both superior edges of the buccal osteotomy, the inner corner at the proximal segment, and the outer corner at the distal segment are removed to allow easy insertion of the specially designed bone cleaver.
FIGURE 4. The bone cleaver with guide is inserted into the anterior superior corner of the proximal segment.
Muto et al. Technical Modification to Sagittal Split Ramus Osteotomy. J Oral Maxillofac Surg 2008.
Muto et al. Technical Modification to Sagittal Split Ramus Osteotomy. J Oral Maxillofac Surg 2008.
1544
TECHNICAL MODIFICATION TO SAGITTAL SPLIT RAMUS OSTEOTOMY
time to complete the split, which is easily accomplished because the cleaver is only 20 mm wide. Keeping the cleaver away from the IAN during this maneuver avoids risk of injuring the nerve. Although the Dal-pont modification of the buccal osteotomy technique has been considered to provide a more stable outcome, it has certain disadvantages compared with osteotomy at the mandibular angle, including unfavorable splitting10 and increased risk of severing the neurovascular bundle.8 Our technique using the specially designed bone cleaver facilitates
FIGURE 6. The bone cleaver positioned at the inferior border of the mandible is rotated to apply force against the inner surface of the proximal segment, with the buccal cortex of the distal segment serving as a fulcrum. Muto et al. Technical Modification to Sagittal Split Ramus Osteotomy. J Oral Maxillofac Surg 2008.
splitting of the ramus without damaging the IAN or other soft tissues.
References
FIGURE 5. The bone cleaver is malleted and rotated to promote splitting, with the buccal cortex of the distal segment acting as a fulcrum. Muto et al. Technical Modification to Sagittal Split Ramus Osteotomy. J Oral Maxillofac Surg 2008.
1. Trauner R, Obwegeser H: The surgical correction of mandibular prognathism and retrognathia with consideration of genioplasty. Oral Surg Oral Med Oral Pathol 10:677, 1957 2. Hunsack EE: A modified intraoral sagittal splitting technique for correction of mandibular prognathism. J Oral Surg 26:250, 1968 3. Epker BN: Modification in the sagittal osteotomy of the mandible. J Oral Surg 35:157, 1977 4. Wolford LM, Bennette MA, Rafferty CG: Modification of the mandibular ramus sagittal split osteotomy. Oral Surg Oral Med Oral Pathol 64:146, 1987 5. Panula K, Finne K, Oikarinen K: Incidence of complications and problems related to orthognathic surgery: A review of 655 patients. J Oral Maxillofac Surg 59:1128, 2001 6. Van de P, Sterling PJW, Blijdorp PA, et al: Perioperative morbidity in maxillofacial orthopaedic surgery: A retrospective study. J Craniomaxillofac Surg 24:263, 1996 7. Panula K, Finne K, Oikarinen K: Neurosensory deficits after bilateral sagittal split ramus osteotomy of the mandible: Influence of soft tissue handling medial to the ascending ramus. Int J Oral Maxillofac Surg 33:543, 2004 8. Fun-Chee L: Technical modification of the sagittal split mandibular ramus osteotomy. Oral Surg Oral Med Oral Pathol 74:723, 1992 9. Tuevey TA: Intraoperative complications of the sagittal osteotomy of the mandibular ramus: Incidence and management. J Oral Maxillofac Surg 43:504, 1985 10. Wolford LM, Davis WM Jr: The mandibular inferior border split: A modification in the sagittal split osteotomy. J Oral Maxillofac Surg 48:92, 1990