Sagittal Ramus Osteotomy Research Articles

The Incidence of Postoperative Wound Healing Problems Following Sagittal Ramus Osteotomies Stabilized With Miniplates and Monocortical Screws

Titanium plates and monocortical screws are commonly used to stabilize the mandible following sagittal split ramus osteotomies. Despite widespread use of this type of fixation, there is a paucity of large studies evaluating the infection rate and need for hardware removal. This study is a retrospective cohort evaluation of 1,066 consecutive mandibular sagittal ramus osteotomies in 533 patients, performed between January 2002 and December 2003. All osteotomies were stabilized with 4-hole miniplates and 2.0 mm x 5.0 mm monocortical screws. Study variables included disturbances of wound healing, age, gender, plate and screw position, direction of mandibular movement, adjunctive procedures performed, and the patient's medical history. Data were collected by chart and radiographic review. The above variables were analyzed using Fisher's exact test, Chi-square, Cochran-Armitage Trend Test, and multiple logistic regression. Of 533 patients 26% (138) demonstrated wound healing problems. This occurred in 15% of all 1,066 osteotomy sites. 6.5% of plates required removal in 10% of patients. In no case did disturbance of wound healing or plate removal result in non-union or relapse of the osteotomy. Wound healing problems were fewer when mandibular osteotomies were done in conjunction with maxillary surgery (18.9% versus 29.1%). Disturbances of wound healing were not related to the direction of movement of the mandible and were lower when hardware was placed closer to the inferior border. An overall low incidence (6.5%) of hardware infection requiring plate removal was found in this study. Screw proximity to the osteotomy site did not correlate with higher rates of healing problems, but there was a statistically significant trend of fewer disturbances of healing when the hardware was placed closer to the inferior border of the mandible.

Retrospective Study of 18 Patients Treated by Maxillomandibular Advancement with Adjunctive Procedures for Obstructive Sleep Apnea Syndrome

A surgical protocol in the treatment of obstructive sleep apnea syndrome (OSAS) is presented. Eighteen patients with particular craniofacial characteristics consisting in maxillomandibular retroposition or retromandibulism underwent bimaxillary advancement by way of Lefort I and bilateral sagittal ramus osteotomies. Adjunctive procedures (genioplasty, uvuloplasty, and glossoplasty) were performed in the same surgical procedure. In all cases, the patients were evaluated before and 6 months after surgery by a physical examination, Delaire cephalometric analysis, and polysomnography. Surgery was considered successful when the postoperative apnea/hypopnea index (AHI) was less than 15/h and with at least a 50% reduction of the initial index. The surgical success rate was 84%. AHI decreased from 54/h (+/-20.7) to 9.66/h (+/-6.67). The results of this study indicate that successful surgical treatment by maxillomandibular advancement with adjunctive procedures at the same operative time is efficient with a high percentage of success when patients are clearly selected.

A Biomechanical Evaluation of Bilateral Sagittal Ramus Osteotomy Fixation Techniques

The purpose of this investigation was to evaluate and compare the biomechanical behavior of various rigid internal fixation plates designed to aid in the condylar positioning of bilateral sagittal ramus osteotomies, to positional screws in an inverted-L pattern, and a control. Fifty polyurethane synthetic mandible replicas (Synbone, Laudquart, Switzerland) were used in this investigation. Five controls and 5 each of 4 different fixation modalities (3 bicortical positional screws in an inverted-L pattern, monocortical 4-hole straight plates, monocortical 6-hole curved plates, and monocortical adjustable 4-hole slide plates) were subjected to vertical loading at the incisal edge and torsional loading at the molar region by an Instron 1331 (Instron, Canton, MA) servohydraulic mechanical testing unit. Mechanical deformation data within a 0 to 900 N range were recorded. Yield load, yield displacement, and stiffness were determined. Means and standard deviations were derived and compared for statistical significance using a Fisher's Protected Least Significant Differences Test with a confidence level of 95% (P < .05). Second-order polynomial best-fit curves were also created for each group to further evaluate mechanical behavior. For incisal edge loading, statistically significant differences were noted between the control group and all other groups for yield load and stiffness, and between the control group and straight, curved, and slide plates for yield displacement. Differences were also noted between the inverted-L and straight, strut, and slide plates for yield load; and inverted-L and straight, curved, and slide, as well as straight and slide for yield displacement. For molar loading, statistically significant differences were noted between the control group and all other groups for yield load and stiffness. Differences were noted between the slide and straight, curved, and control; as well as between the inverted-L and straight and strut plates for yield displacement. Lastly, differences were noted between the straight and curved plates, and the slide and straight, curved, and inverted-L for stiffness. In this in vitro study, differences were noted between the control and all experimental groups in their abilities to resist loads under all of the conditions tested. Differences were also noted among specific experimental groups. Yet when placed in the context of functional parameters, only the bicortical positional screws in an inverted-L pattern met the requirements for both molar loading and incisal edge loading.

The Incidence of Hardware Infection Following Sagittal Ramus Osteotomies Stabilized With Miniplates and Monocortical Screws

The Incidence of Hardware Infection Following Sagittal Ramus Osteotomies Stabilized With Miniplates and Monocortical Screws

Definitive surgical correction of the deformity resulting from hemimandibular hyperplasia

The asymmetric deformity of the mandible resulting from the rare condition of hemimandibular hyperplasia has posed a challenge for aesthetic surgical correction. The literature relating to this condition is reviewed and the results of treatment in a series of patients described. A series of treated patients is reviewed and the results of surgery illustrated and discussed. A maxillary Le Fort I osteotomy is first performed where levelling of the occlusal plane is required. The mandibular surgical technique commences with an extended sagittal ramus osteotomy with dissection of the inferior dental neurovascular bundle completely free of the mandible up to and including the mental foramen. The proximal fragment is then rotated cranially leaving undisturbed the soft tissue attachments at the inferior border, with corresponding bone reduction at the upper border. The inferior border of the distal fragment is then reduced to match the new position of the lower border of the proximal fragment, the neurovascular bundle repositioned, and rigid fixation applied. Finally, a straightening genioplasty is performed. It was possible to overcome the technical and anatomical difficulties associated with correction of this hemimandibular deformity and to achieve a good aesthetic result with acceptable facial symmetry when applying this surgical technique in 3 patients. Hemimandibular hyperplasia can be surgically corrected with good aesthetic and functional results and minimal morbidity.

Prevention of bad split of the proximal segment during bilateral sagittal ramus osteotomy

Prevention of bad split of the proximal segment during bilateral sagittal ramus osteotomy

Bimaxillary osteotomy with and without condylar positioning--a 1981-2002 long-term study

The introduction of the four-splint technique in our hospital in 1997 made possible the reproducible centric condyle positioning in bimaxillary osteotomies, while taking the auto rotation of the mandible into consideration and avoiding steps in the mandibular osteotomy line. From 1981 to 2002 a total of 622 patients underwent bimaxillary osteotomy surgery. During 1981-1997 a total of 395 patients (63.5%) underwent surgery without or only with centric condyle positioning in sagittal ramus osteotomy of the mandible. During 1997-2002 a total of 227 patients (36.5%) underwent surgery with continuous centric condyle positioning with the four-splint technique. In patients with preoperative functional disorders, surgery with continuous centric condyle positioning resulted in statistically significant (p<0.05) improvement compared to those who underwent surgery without continuous centric condyle positioning. The results confirm the indication for continuous centric condyle positioning in bimaxillary osteotomies.

Control of the proximal segment during application of rigid internal fixation of sagittal split osteotomy of the mandible

Control of the proximal fragment during sagittal ramus osteotomy is important to achieve a stable desired change in centric relation of the mandible after either anterior or posterior repositioning. Failure to accomplish this often leads to decreased stability of the surgical result, adversely affects the temporomandibular joint apparatus, and decreases masticatory efficiency.1 Failure to control the proximal fragment can result in occlusal discrepancies that cannot be fully corrected with orthodontic therapy.

Orthognathic surgery

Mandibular deficiency is the most common dentofacial deformity requiring a combination of orthodontic and surgical treatment. The bilateral sagittal ramus osteotomy (BSRO) has been the surgery of choice for correction of mandibular deficiency since the early 1970s. Refinements in surgical technique and the addition of rigid internal fixation have significantly decreased the morbidity of this procedure and provided satisfactory results in the surgical correction of a wide variety of mandibular abnormalities. The BSRO has been widely studied and outcomes documented using a variety of criteria including stability, TMJ implications, cosmetic improvement, neurosensory issues, and complications.

Study by finite element method of the mechanical stress of selected biodegradable osteosynthesis screws in sagittal ramus osteotomy

We tested the stability of the bilateral sagittal split osteotomy using four resorbable osteosynthesis screws (the PLLA screw introduced by Harada and Enomoto, the Isosorb® screw, the BioSorbFX® screw and the Lactosorb® screw) which are all currently in clinical use. The distribution of stress in both the bicortically inserted screws and the adjacent bone of a computer-generated mandible was recorded by the three-dimensional finite element method. The stress of the materials under investigation was postulated to have reached threshold values for stability, and maximum chewing forces of 132 N (Harada and Enomoto), 117 N (Isosorb®), 115 N (BioSorbFX®) and 46.4 N (Lactosorb®) were determined.As far as the postoperative chewing forces were concerned, all four screws were sufficiently stable at the osteotomy gap. Finite element modelling seems to be an appropriate method of investigating these clinical issues when the mechanical stress both in implants and in the adjacent bone is taken into account.

Discussion

This article confirms earlier reports 1 Epker BN Fish LC Dentofacial Deformities. Integrated Orthodontic and Surgical Correction. vol 1. Mosby, St Louis, MO1986 Google Scholar , 2 Precious DS Lung KE Goodday RH Incidence of mandibular fracture in 1256 SSO with and without impacted third molar teeth. J Oral Maxillofac Surg. 1993; 51: 141 Google Scholar , 3 Tucker MR Sagittal ramus osteotomy with and without impacted third molars. J Oral Maxillofac Surg. 1995; 53: 80 Abstract Full Text PDF PubMed Scopus (7) Google Scholar , 4 Precious DS Lung KE Pynn BR et al. Presence of impacted teeth as a determining factor of unfavorable splits in 1256 sagittal-split osteotomies. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1998; 85: 362 Abstract Full Text PDF PubMed Scopus (58) Google Scholar that third molars can be removed safely and effectively at the time of sagittal split osteotomy (SSO). The authors report an overall unwanted fracture rate of 2.2% (n = 500 SSOs), which is similar with that (1.9%) previously reported by others (n = 1,256 SSOs). 4 Precious DS Lung KE Pynn BR et al. Presence of impacted teeth as a determining factor of unfavorable splits in 1256 sagittal-split osteotomies. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1998; 85: 362 Abstract Full Text PDF PubMed Scopus (58) Google Scholar

Preliminary investigation of the biomechanics of internal fixation of sagittal split osteotomies with miniplates using a newly designed in vitro testing model

Purpose: This article reports a preliminary study undertaken to investigate the biomechanics of internal fixation systems for sagittal split ramus osteotomy of the mandible with advancement, using a newly designed 3-point bovine rib testing model. Materials and Methods: After 1 of 5 different miniplates internal fixation systems was placed, a vertical load was applied just below the superior border of sagittal split osteotomy gaps in bovine ribs positioned in a custom-made cradle using a compound cantilered bar device. Load/displacement data were gathered, and the mean elastic limits of the 5 miniplate designs were compared by using a 1-way analysis of variance (ANOVA) with Tukey multiple comparisons. Results: The elastic limit of the rigid fixation system was higher when using a curved plate design than with a straight plate design. Conclusion: The 3-point bovine rib model used in this study is an inexpensive, discriminating, and reproducible method for testing internal fixation systems on sagittal ramus osteotomies under conditions that more accurately represent the human mandible in function. © 2001 American Association of Oral and Maxillofacial Surgeons

A modified mandibular ramus osteotomy for orthognathic surgery

Several procedures have been described for correction of orthognathic deformities of the mandible. Currently, the bilateral sagittal split osteotomy (BSSO) maintains its popularity because of its versatility and its amenability to rigid fixation techniques. The distal segment of the mandible can be repositioned in all planes of space, and the bony interface along the osteotomy results in predictable healing. However, there are well-known disadvantages to the procedure, which include neurosensory disturbance, 1 Pratt CA Labial sensory function following sagittal split osteotomy. Br J Oral Maxillofac Surg. 1996; 34: 75 Abstract Full Text PDF PubMed Scopus (43) Google Scholar , 2 Posnick J Alteration in facial sensibility in adolescents following sagittal split and chin osteotomies of the mandible. Plast Reconstr Surg. 1996; 97: 920 Crossref PubMed Scopus (67) Google Scholar , 3 Lemke RR Effects of hypesthesia on oral behaviors of the orthognathic surgery patient. J Oral Maxillofac Surg. 1998; 56: 153 Abstract Full Text PDF PubMed Scopus (26) Google Scholar , 4 Jacks SC A retrospective analysis of lingual nerve sensory changes after mandibular bilateral sagittal split osteotomy. J Oral Maxillofac Surg. 1998; 56: 700 Abstract Full Text PDF PubMed Scopus (50) Google Scholar , 5 Fujioka M Comparative study of inferior alveolar disturbance restoration after sagittal split osteotomy by means of bicortical versus monocortical osteosynthesis. Plast Reconstr Surg. 1998; 102: 37 Crossref PubMed Scopus (45) Google Scholar , 6 Blomqvist JE Sensibility following sagittal split osteotomy in the mandible: A prospective clinical study. Plast Reconstr Surg. 1998; 102: 325 Crossref PubMed Scopus (52) Google Scholar , 7 August M Neurosensory deficit and functional impairment after sagittal ramus osteotomy: A long-term follow-up study. J Oral Maxillofac Surg. 1998; 56: 1231 Abstract Full Text PDF PubMed Google Scholar , 8 Westermark A Inferior nerve function after mandibular osteotomies. Br J Oral Maxillofac Surg. 1998; 36: 425 Abstract Full Text PDF PubMed Scopus (174) Google Scholar , 9 Westermark A Inferior alveolar nerve function after sagittal split osteotomy of the mandible: Correlation with degree of intraoperative nerve encounter and other variables in 496 operations. Br J Oral Maxillofac Surg. 1998; 36: 429 Abstract Full Text PDF PubMed Scopus (139) Google Scholar condylar displacement, 10 Magalh-aes AE Changes in condylar position following bilateral sagittal split ramus osteotomy with setback. Int J Adult Ortho Orthognath Surg. 1995; 10: 137 PubMed Google Scholar , 11 Van Sickels JE Condylar torque as a possible cause of hypomobility after sagittal split osteotomy: Report of three cases. J Oral Maxillofac Surg. 1997; 55: 398 Abstract Full Text PDF PubMed Scopus (20) Google Scholar , 12 Nishimura A Positional changes in the mandibular condyle and amount of mouth opening after sagittal split ramus osteotomy with rigid or nonrigid osteosynthesis. J Oral Maxillofac Surg. 1997; 55: 672 Abstract Full Text PDF PubMed Scopus (33) Google Scholar , 13 Van Sickels JE Condylar position with rigid fixation versus wire osteosynthesis of a sagittal split advancement. J Oral Maxillofac Surg. 1999; 57: 31 Abstract Full Text PDF PubMed Scopus (32) Google Scholar and unfavorable splits. 14 Martis CS Complications of the mandibular sagittal split osteotomy. J Oral Maxillofac Surg. 1984; 42: 101 Abstract Full Text PDF PubMed Scopus (146) Google Scholar , 15 Van Sickels JE Jeter JE Theriot BA Management of an unfavorable lingual fracture during a sagittal split osteotomy. J Oral Maxillofac Surg. 1985; 43: 808 Abstract Full Text PDF PubMed Scopus (26) Google Scholar , 16 Turvey TA Intraoperative complications of sagittal osteotomy of the mandibular ramus: Incidence and management. J Oral Maxillofac Surg. 1985; 43: 504 Abstract Full Text PDF PubMed Scopus (104) Google Scholar , 17 Marquez IM Modification of the sagittal split osteotomy to avoid unfavorable fracture around impacted third molars. Int J Adult Ortho Orthognath Surg. 1998; 13: 183 PubMed Google Scholar

Low-level laser effect on neurosensory recovery after sagittal ramus osteotomy.

This study examined the potential benefit of perioperative and short-term postoperative low-level laser (LLL) therapy on objective and subjective neurosensory recovery after bilateral sagittal split osteotomy surgery. Six consecutive patients undergoing bilateral sagittal split osteotomy procedures were enrolled in this prospective study. A complete preoperative clinical neurosensory test, consisting of brush stroke directional discrimination, 2-point discrimination, contact detection, pin prick nociception, and thermal discrimination, was performed on each patient; and a subjective assessment of neurosensory function was made by using a visual analog scale (VAS). The protocol for LLL treatments consisted of real LLL (4 x 6 J per treatment) along the distribution of the inferior alveolar nerve at 4 sites, for a total of 7 treatments, delivered immediately before surgery; at 6 and 24 hours after surgery; and on postoperative days 2, 3, 4, and 7. The clinical neurosensory test and VAS were completed just before each of the treatment sessions and on days 14 and 28, by one examiner. When the results of the patients treated with LLL were compared with published values for neurosensory recovery after orthognathic surgery, there was a significant acceleration in the time course, as well as in the magnitude, of neurosensory return. Brush stroke directional discrimination approached normal values by 14 days, whereas 2-point discrimination and contact detection showed significant improvement at 14 days and returned to near-normal values by 2 months. The results of thermal discrimination and pin prick nociception revealed few neurosensory deficits; however, those patients who were affected showed a slower recovery trend and remained neurosensory-deficient for up to 2 months. The VAS analysis revealed a rapidly progressive improvement in subjective assessment, showing a 50% deficit at 2 days and only a 15% subjective deficit at 2 months. This study demonstrates that neurosensory recovery after bilateral sagittal split osteotomy procedures can be significantly improved, both in terms of time course and magnitude of return of function, with the adjunctive use of LLL therapy.

下顎非対称症例に片側下顎枝垂直骨切り術を用いた１例

A case of mandibular asymmetry of a 19-year-old male is reported. The unilateral sagittal ramus osteotomy combined with contralateral intraoral vertical ramus osteotomy was performed on this case. Although the occlusion and the jaw movement were seemingly improved at the end of active orthogna-thic treatment, new symptoms of temporomandibular joint were observed during the retention period, which required further follow-up.

Neurosensory deficit and functional impairment after sagittal ramus osteotomy: A long-term follow-up study

Neurosensory deficit and functional impairment after sagittal ramus osteotomy: A long-term follow-up study

Neurosensory deficit and functional impairment after sagittal ramus osteotomy: A long-term follow-up study

Purpose: This study evaluated persistent neurosensory deficit (NSD) and functional sensory deficit (FSD) after mandibular bilateral sagittal split osteotomies (BSSO) and their association with patient age at time of operation and eight additional variables. Patients and Methods: Eighty-five patients more than 2 years post-BSSO were identified and stratified by age: group 1, 10 to 19 years (n = 16); group 2, 20 to 29 years (n = 24); group 3, 30 to 39 years (n = 30); group 4, older than 40 years (n = 15). Mean mandibular advancement, incidence of “bad split,” excessive intraoperative bleeding, nerve manipulation, removal of third molars, use of rigid fixation, simultaneous mandibular procedures, and associated systemic disease were documented for each group. A questionnaire modified from Zuniga was used to document the presence of persistent (2 years or longer) NSD and FSD. Statistical analysis was performed to determine differences between groups. Logistic regression was used to evaluate each variable and determine its association with persistent NSD and FSD. Results: Persistent NSD by age was: group 1, 81%; group 2, 46%; group 3, 73%; group 4, 87%. The trend of increasing persistence with increasing age was not significant ( P = .248). However, persistent FSD with increasing age was highly significant ( P = .003). The incidence of FSD in group 4 was statistically greater than in the other groups ( P < .001; P < .001; P = .004, respectively). Logistic regression identified patient age and “bad splits” as associated with FSD ( P = .003; P = .015, respectively). Conclusions: The incidence of persistent FSD more than 2 years post-BSSO increases with increasing age in a predictable and highly significant manner. Presurgical counseling should address this issue. FSD is also significantly associated with “bad splits.” No other variables were found to be significant.

Modified channel retractor simplifies sagittal ramus osteotomy procedure.

A new instrument is described for use in the sagittal ramus split osteotomy by Obwegeser. This modified channel retractor simplifies the sagittal ramus osteotomy procedure, allows clear vision and easy access, and protects adjacent tissues.

An in vitro comparison of the mechanical characteristics of three sagittal ramus osteotomy fixation techniques

Purpose: The purpose of this in vitro investigation was to compare the mechanical characteristics of three techniques for the rigid internal fixation of simulated sagittal ramus osteotomies in terms of their ability to resist vertical loads resembling masticatory forces. Materials and Methods: Fifteen bovine ribs of similar size and shape were subjected to uniform osteotomies resembling a sagittal ramus osteotomy. They were divided into three groups and fixed with three 2.0-mm bicortical positional screws in an inverted L-pattern, eight monocortical screws and a sagittal strut plate, or a hybrid system using three 2.0-mm bicortical positional screws, five 2.0-mm monocortical screws, and a sagittal strut plate. The repaired ribs were secured in a jig, subjected to vertically deforming forces, and evaluated for yield load, yield point, maximum load, displacement at maximum load, load at 3.0 mm displacement, and stiffness. The various groups were compared statistically with a Scheffe multiple comparison test. Results: No statistically significant differences existed between the positional screw group and the hybrid group ( P > .05). No statistically significant differences were noted in yield displacement, yield load, displacement at maximum load, for any of the groups ( P > .05). There were differences noted between the monocortical strut group and other groups in maximum load, load at 3.0 mm displacement, and stiffness ( P > .05). Conclusions: The monocortically fixed sagittal strut plate offers less resistance to maximum load and loads at 3.0 mm displacement and is less stiff than either a three-positional screw system or a hybrid system. No differences existed between the three positional screw systems and the hybrid system. However, given the low yield loads and yield displacements, these differences may not be clinically important.

An in vitro comparison of the mechanical characteristics of three sagittal ramus osteotomy fixation techniques

An in vitro comparison of the mechanical characteristics of three sagittal ramus osteotomy fixation techniques