Sagittal Split Ramus Osteotomy Research Articles

Orthodontic and Orthognathic Treatment Combined withSurgically Assisted Rapid Maxillary Expansion in an Adult Patient with a Hyperdivergent Skeletal Pattern.

In this case study, we report the successful treatment of a 35-year-old woman with a hyperdivergent skeletal pattern, open bite and severe transverse deficiency, exhibiting a skeletal Class III malocclusion. The treatment plan included 3D correction of these issues with surgically assisted rapid maxillary expansion (SARME) to solve the transverse deficiency, presurgical orthodontic treatment including aligning and levelling of the teeth in both arches, LeFort I osteotomy and bilateral sagittal split ramus osteotomy, and postsurgical correction of malocclusion. Orthodontic treatment was performed with labial brackets, and the patient achieved satisfactory occlusion and a significantly improved facial profile. Retention at the 1-year follow-up showed stable occlusion and arch forms with a harmonious facial profile.

BSSRO Improves Mandibular Morphology Mainly through Correction of Body Length and Volume in Patients with Asymmetric Mandibular Prognathism.

Purpose: The purpose of this study is to analyze the change and stability of mandibular morphology in patients with asymmetric mandibular prognathism after bilateral sagittal split ramus osteotomy (BSSRO). Methods: We retrospectively analyzed fifty patients with asymmetric mandibular prognathism from the West China Hospital of Stomatology, Sichuan University, between January 2018 to March 2021. The spiral CT data before surgery, within two weeks after surgery, and at more than six months after surgery of each patient were collected. According to the deflection direction of the chin, the bilateral mandibles were defined as the long side and the short side. The morphological data of the bilateral condyle, the mandibular ramus, and the mandibular body were analyzed to determine the effect and stability of BSSRO on asymmetric mandibular prognathism. Results: It was found that the long-side mandible had greater condylar volume and diameter, mandibular ramus height and volume, and mandibular body length and volume (p < 0.05) before surgery. After surgery, the volume of the mandibular ramus increased, while the length and volume of the mandibular body decreased (p < 0.05) at the long side of the mandible; the morphological changes of the mandibular ramus and body at the short side of the mandible were not statistically significant (p > 0.05). When comparing the long and short sides of the mandible, the long side still had greater height and volume of the mandibular ramus (p < 0.01). The volume difference of the mandibular body from the two sides was corrected (p > 0.05), and the length difference of the mandibular body from the two sides was overcorrected (p < 0.05). At more than six months after surgery, the volume of the mandibular ramus and body increased, while their height decreased at the long side of the mandible (p < 0.05). For the other side, or the short side, the volume of the ramus and body increased, too. However, their height decreased (p < 0.01). Conclusion: The results of this study suggested good effect and stability of BSSRO on asymmetric mandibular prognathism, except for the correction of ramus height and volume.

Changes in the condylar head after orthognathic surgery in Class III patients: a retrospective three-dimensional study.

To evaluate the axial and dimensional changes of the condylar head after orthognathic surgery, including Le Fort I and bilateral sagittal split ramus osteotomies, and to assess condylar remodeling through three-dimensional (3D) surface superimposition. Twenty-four patients (15 females, 9 males; mean age: 32.22 ± 6.92 years) with skeletal Class III deformity were included in the study. Cone-beam computed tomography data obtained in the preoperative (T0) and postoperative (T1) periods were examined using Mimics and 3-Matic software. The height, depth, and width of the condylar head and its angular changes were measured. The volumes of the 3D reconstructed models were calculated, and remodeling amounts were evaluated through regional surface superimposition. Statistical significance was set at P < .05. Following the surgery, there was a significant decrease in the size of condyles (P < .05). An inward rotation of the condyles was found in the axial plane (T0: 79.60 ± 6.01°, T1: 76.6 ± 6.48°, P < .05). The maximum resorption, maximum apposition, mean remodeling, and mean absolute remodeling were -2.63 ± 1.23 mm, 1.15 ± 0.4 mm, -0.30 ± 0.34 mm, and 0.73 ± 0.43 mm, respectively. No correlation was found between the angular changes and remodeling parameters or linear and volumetric changes of the condylar head (P > .05). Condyles undergo a remodeling process with a resorptive character following orthognathic surgery, without clinically significant effects in the present study.

The proximal segment in sagittal split ramus osteotomy

Bilateral sagittal split ramus osteotomy is one of the most versatile techniques in orthognathic surgery that allows for the repositioning of the mandible in all directions. This osteotomy splits the mandible into two proximal condyle-bearing segments and one distal tooth-bearing segment. Intraoperatively, the surgeon is usually focused primarily on the proper positioning of the distal segment to achieve the planned amount of advancement or setback. However, particular attention should be paid to the position of the proximal segment, as improper positioning of the proximal segment during fixation gives rise to immediate or late relapse of the surgical outcomes. The goal of this paper is to provide some background knowledge about the proximal segment for the novice surgeons, based on a review of the relevant literature. What is the proper position of the proximal segment, and what is the best technique to guide the proximal segment into its proper position?. These questions do not have clear-cut answers that the majority of surgeons agree on.

Biomechanical comparison of the effect of bilateral sagittal split ramus osteotomy with or without Le Fort I osteotomy on the temporomandibular joints of the patients with maxillofacial deformities under centric occlusion

Mandibular deformities negatively affect the daily activities of the patients and may cause temporomandibular disorders (TMD). Bilateral sagittal split ramus osteotomy (BSSRO) and Le Fort I osteotomy are effective treatments to correct the mandibular deformities. The aim of this study was to investigate and compare the effects of the BSSRO with or without Le Fort I on the stress distributions of the temporomandibular joints (TMJs) of the patients with mandibular deformities under centric occlusion based on finite element (FE) method. Preoperative and postoperative cone-beam computed tomography (CBCT) images of twenty-four patients diagnosed with mandibular prognathism, including ten patients with BSSRO and another 14 patients with bimaxillary osteotomy (BSSRO with Le Fort I), were used to construct maxillofacial models. Ten asymptomatic individuals were also performed CBCT scanning and defined as the control group. In addition, the muscle forces and boundary conditions corresponding to centric occlusions were applied on each model. For the preoperative groups with both the BSSRO and bimaxillary osteotomies, the average peak contact stresses of the TMJs were both greater than those of the control group. After the surgeries, the contact stresses of the discs and temporal bones of both groups considerably decreased. However, the contact stresses on the condyles slightly increased after BSSRO but decreased after bimaxillary osteotomy. The TMJs of the patients with maxillofacial deformities suffered abnormal tensile and compressive stresses compared with the asymptomatic subjects under centric occlusion. Both of the BSSRO and bimaxillary osteotomy could improve the risk stress distributions of the TMJs.

Reconstruction of Dentomaxillofacial Deformity Secondary to Mandibular Defect Using Concomitant Orthognathic Surgery and Fibula Free Flap.

The reconstruction of mandibular defects may be delayed or compromised for many reasons, especially in pediatric patients. With the growth of the remaining mandible and the maxilla in the malocclusion status, secondary dentomaxillofacial deformity is plausible. To treat the concomitant mandibular defect and secondary dentomaxillofacial deformity, a hierarchical algorithm using orthodontics, orthognathic surgery, and fibula free flap was developed. This retrospective case series included six patients with long-term mandibular defects caused by tumor resection without repair or with compromised costochondral reconstruction. All patients were treated using the same staged protocol, but with minor changes: (1) presurgical orthodontics, (2) virtual surgical planning, (3) fabrication of the guides and splints, (4) sequenced operations, and (5) postoperative care. The sequence of surgery included the Le Fort I osteotomy, mandibular sagittal split ramus osteotomy of the remaining ramus, final occlusion registration, repositioning of the distal segment of the mandible, segmented fibula reconstruction, and finally, the fixation of mandibular sagittal split ramus osteotomy. The operations and wound healing were uneventful in all patients, and no flap failure or severe complications were detected. Also, the patients exhibited no signs of temporomandibular joint ankylosis during the follow-up. The subspinale-nasion-supramental angle was significantly reduced after surgery. A significant improvement was detected in the facial contour symmetry measurements postoperatively. This proposed workflow of concomitant orthognathic surgery and the fibula free flap is effective and reliable for the reconstruction of dentomaxillofacial deformity secondary to the long-term mandibular defect.

Surgical Orthodontic Treatment of Class II Malocclusion with Facial Asymmetry

This case report describes a successful surgical orthodontic treatment of a Class II malocclusion with facial asymmetry. An 18-year-old female visited our dental clinic due to proclined anterior teeth and facial asymmetry. Straight facial profile and skeletal Class II was observed. The frontal cephalometric analysis showed that the left ramus length was longer and the left ramal angle was greater than the right. After extraction of the maxillary and mandibular second premolars, dental arch was decompensated. After presurgical orthodontic treatment, bilateral sagittal split ramus osteotomy (BSSRO) was performed. Facial asymmetry was improved, but posterior open bite on the right was occurred by insufficient dental decompensation. To prevent recurrence of the mandible, a bite stop was made by bonding resin on the lingual side of the right maxillary canine. This prevented the recurrence of the mandibular rolling and yawing with the use of bilateral intermaxillary elastics. The right mandibular posterior part with open bite was segmented from the main arch wire and was extruded with intermaxillary elastic. Fast occlusal stabilization was achieved by using the rapid tooth movement after surgery. Since intermaxillary elastic was used while applying an intrusion force with a micro-implant to the left posterior region, it was possible to stabilize the mandible while prevent tooth extrusion. After treatment, facial symmetry and good occlusal relationship were achieved.

Redundancy of the Visual Identification of Lingula in the Bilateral Sagittal Split Ramal Osteotomy Procedure of the Mandible.

The bilateral sagittal split ramus osteotomy (BSSRO) is the technique in vogue which is used for correction of a range of mandibular corpus deformity involving the dentoalveolar segment. The surgical technique has been subjected to a variety of modifications ever since its inception in the 1950s. One of the operative objectives which has been advocated sacrosanct has been the visual identification of lingula during the exposure of the medial aspect of the ramus. BSSRO was successfully carried out in 45 cases operated over a period of eight years for correction of different kinds of skeletal mandibular deformity. The medial subperiosteal dissection did not involve a visual identification of the lingula. In our experience, the visual identification of the lingula is not essential to carry out a safe BSSRO procedure.

Accuracy of Segmented Le Fort I Osteotomy with Virtual Planning in Orthognathic Surgery Using Patient-Specific Implants: A Case Series.

Background: When maxillary transversal expansion is needed, two protocols of treatment can be used: a maxillary orthodontic expansion followed by a classical bimaxillary osteotomy or a bimaxillary osteotomy with maxillary segmentation. The aim of this study was to assess the accuracy of segmented Le Fort I osteotomy using computer-aided orthognathic surgery and patient-specific titanium plates in patients who underwent a bimaxillary osteotomy for occlusal trouble with maxillary transversal insufficiencies. Methods: A virtual simulation of a Le Fort I osteotomy with maxillary segmentation, a sagittal split ramus osteotomy, and genioplasty (if needed) was conducted on a preoperative three-dimensional (3D) model of each patient’s skull using ProPlan CMF 3.0 software (Materialise, Leuven, Belgium). Computer-assisted osteotomy saw-and-drill guides and patient-specific implants (PSIs, titanium plates) were produced and used during the surgery. We chose to focus on the maxillary repositioning accuracy by comparing the preoperative virtual surgical planning and the postoperative 3D outcome skulls using surface superimpositions and 13 standard dental and bone landmarks. Errors between these preoperative and postoperative landmarks were calculated and compared to discover if segmental maxillary repositioning using PSIs was accurate enough to be safely used to treat transversal insufficiencies. Results: A total of 22 consecutive patients—15 females and 7 males, with a mean age of 27.4 years—who underwent bimaxillary computer-assisted orthognathic surgery with maxillary segmentation were enrolled in the study. All patients presented with occlusion trouble, 13 with Class III malocclusions (59%) and 9 (41%) with Class II malocclusions. A quantitative analysis revealed that, overall, the mean absolute discrepancies for the x-axis (transversal dimension), y-axis (anterior–posterior dimensions), and z-axis (vertical dimension) were 0.59 mm, 0.74 mm, and 0.56 mm, respectively. The total error rate of maxillary repositioning was 0.62 mm between the postoperative cone-beam computed tomography (CBCT) and the preoperatively planned 3D skull. According to the literature, precision in maxilla repositioning is defined by an error rate (clinically relevant) at each landmark of <2 mm and a total error of <2 mm for each patient. Conclusions: A high degree of accuracy between the virtual plan and the postoperative result was observed.

Modified Le Fort I Arc Osteotomy Combined With Autologous Bone Grafts to Improve Midface Hypoplasia Combined With Skeletal Class III Malocclusion: A Technical Note.

Midface hypoplasia sometimes appears in patients with skeletal class III malocclusion in the Asian population, often requires additional surgical treatments. The technical note is intended to introduce a modified Le Fort I arc osteotomy combined with autologous bone grafts harvested from proximal segments after bilateral sagittal split ramus osteotomy to improve the profile for skeletal class III malocclusion patients with midface hypoplasia. The benefit of the modified technology is that the size and position of the arc can be adjusted according to the severity of the deformity to suit different patients. In addition, the application of autologous bone grafts increased the extra height of osteotomy line and enhanced the surgical effect, and maintained bone consolidation. More importantly, the osteotomy line of the modified Le Fort I arc osteotomy can be easily designed and this modification will not cause additional injuries. Therefore, we believe that for skeletal class III malocclusion patients with midface hypoplasia in Asia modified Le Fort I arc osteotomy combined with autologous bone grafts will be an efficient surgical method to improve midface hypoplasia.

Ambulatory sagittal split ramus osteotomy: strategy for enhanced recovery after surgery

The sagittal split ramus osteotomy (SSRO) has been performed mainly on an inpatient basis because of the duration of anaesthesia and the potential risk of postoperative complications, such as bleeding, pain, nausea, and vomiting. However, advances in both surgical and anaesthetic management have enabled the reduction of these risks and shortened the length of hospital stay. Thus, the SSRO may be feasible even in the ambulatory setting in elective cases. The clinical records of all patients who underwent an outpatient SSRO between August 2011 and September 2020 at Lilla Craniofacial Clinic were reviewed retrospectively. Data on age, sex, duration of surgery, operative procedures, intraoperative bleeding, and admission status were investigated. In total, 143 patients underwent a bilateral SSRO. The SSRO was performed as an isolated procedure in 73 patients and concomitantly with other surgical procedures in the remaining 70 patients. Overall, 142 of the 143 patients were discharged on the day of surgery (99.3%); only one (0.7%) required an overnight stay because of a submental haemorrhage after genioplasty. No emergency hospitalizations or readmissions occurred after discharge. Multimodal perioperative management, both surgical and anaesthetic, facilitated enhanced patient recovery after surgery, and SSRO was performed successfully and safely as an ambulatory procedure.

Effect of Orthognathic Surgery on Movement of the Cheilion.

The cheilion (Ch), corner of the mouth, is the soft-tissue landmark where the upper and lower lips intersect. Orthognathic surgery can modify Ch position, which can affect facial esthetics. The aims were to evaluate Ch movements resulting from Le Fort I maxillary advancement with maxillary impaction or downgrafting, and with mandibular advancement or setback, and to investigate relationships between surgical movements and Ch movements. The 45 patients had undergone bilateral sagittal split ramus osteotomy with Le Fort I advancement surgery. They were divided into 4 groups according to surgical movement direction. Preoperative and postoperative photographs were calibrated. Standardized methods were used to identify and measure preoperative and postoperative Ch positions. Significant correlations were detected between extent of maxillary downgrafting and inferior movement of the Ch in group 1 ( r =0.988, P =0.001) and group 3 ( r =0.915, P =0.001). Also, significant correlations were detected between extent of mandibular advancement and anterior movement of the Ch in group 3 ( r =0.561, P =0.046) and group 4 ( r =0.661, P =0.005). The findings indicate that, in patients who undergo bilateral sagittal split ramus osteotomy/Le Fort I surgeries, mandibular advancement moves Ch anteriorly and maxillary downgrafting moves Ch inferiorly.

Stroke Due to Orthognathic Surgery: Case Report of a Rare Complication

Summary:Le Fort I osteotomy is a frequent surgical procedure used in orthognathic surgeries to treat severe malocclusions and is associated with relatively rare surgical complications. Here, the authors report a case of thrombotic ischemic stroke as a result of this procedure, a complication still not described in the literature. A 19-year-old man with class II malocclusion and retrognathia underwent orthognathic surgery for aesthetic purposes. The surgery included a Le Fort I maxillary osteotomy with vertical impaction, bilateral sagittal split ramus osteotomy for mandibular advancement, and genioplasty. Postoperatively, the patient developed left eye blindness, headache, somnolence, aphasia, and right hemiplegia. Medical imaging showed the Le Fort I line of fracture extending from the maxillary osteotomy to the left optic canal and to the left carotid canal, with osseous fragments impinging the petrous segment of the internal carotid artery, left carotid artery occlusion and associated to an ischemic stroke at the left middle cerebral artery territory. Treatment required decompressive craniectomy and later focused on clinical stabilization, infection management, orthognathic care, neurorehabilitation, and cranioplasty. The hemiplegia and aphasia partially recovered during 12 months, and final dental occlusion was appropriate. Our report demonstrates that an unfavorable Le Fort I fracture trajectory can lead to ischemic stroke and severe neurological deficits.

Three-Dimensional Quantitative Assessment of Condylar Displacement and Adaptive Remodeling in Asymmetrical Mandibular Prognathism Patients After Sagittal Split Ramus Osteotomy.

This study was performed to evaluate the condylar displacement and associated condylar remodeling in class III patients following mandibular setback surgery via sagittal split ramus osteotomy (SSRO). The sample comprised of 26 condyles of 13 subjects (mean age of 21.2±2.6y). We evaluated patients with mandibular prognathism and facial asymmetry who had undergone SSRO for mandibular setback at Korea University Hospital between January 2016 and December 2018. Three-dimensional segmentation of the mandibular condyles was done using the initial cone-beam computed tomography scan and scan taken 12 months postoperatively or later. Quantitative assessments of the 3-dimensional condylar displacement from T0 to T1 and bony remodeling of 8 regions of the condylar head were performed. The correlation between the condylar displacement and condylar head remodeling on the deviated (D) and nondeviated (ND) sides was analyzed. Significant correlations between condylar displacement and surface remodeling were observed in both D and ND condyles. The anteroposterior condylar displacement was significantly different between the D and ND sides (P=0.007). There was no significant difference in condylar remodeling between the 2 sides. Condylar displacement and adaptive remodeling after SSRO varied greatly among individuals. Compared with displacement in the ND condyle, displacement in the D condyle has a greater association with condylar remodeling in both D and ND condyles. There is no significant difference in condylar head remodeling between D and ND condyles.

Influence of different treatment procedures on the temporomandibular joint after mandibular setback in skeletal class III - A retrospective study

The aim of this study was to clarify the effects of three different orthognathic surgical procedures on the temporomandibular joint after mandibular setback. Conventional sagittal split ramus osteotomy (SSRO) with segmental fixation (conv-SSRO), intraoral vertical ramus osteotomy (IVRO), or SSRO without fixation followed by the physiological positioning strategy (nonfix-SSRO) was performed for mandibular setback. Temporomandibular joint disorder (TMD) symptoms were clinically assessed, and the condylar head angle was measured. In total, 129 patients participated. Preoperative TMD and treatment procedure were related to postoperative TMD. A menton deviation of 3.43 mm was the cutoff for the risk of postoperative TMD. The incidence rate of postoperative TMD in the conv-SSRO group was higher than that in the IVRO (p = 0.0197) and nonfix-SSRO (p = 0.0001) groups in asymmetric cases. There was no significant postoperative change in the temporomandibular joint space in each group. In symmetric and asymmetric cases, the condylar head was rotated inwards by 5.82 ± 4.75° (p < 0.0001) and 5.44 ± 3.10° (p < 0.0001), respectively, in the conv-SSRO group, and outwards by −7.98 ± 5.05° (p < 0.0001) and −8.32 ± 6.38° (p < 0.0001), respectively, in the IVRO group, but it was almost stable in the nonfix-SSRO group. Within the limitations of the study it seems that nonfix-SSRO should be preferred over conv-SSRO and IVRO whenever appropriate.

Comparative evaluation of stress distribution and transverse displacement of novel designs of miniplates for sagittal split ramus osteotomy in 10 mm advancements: a finite element analysis

The aim of this study was to evaluate the stress distribution and displacement values of six different miniplate systems in large mandibular advancement after sagittal split ramus osteotomy (SSRO) with finite element analysis (FEA). A three-dimensional model of a mandible was created and a 10 mm advancement SSRO was simulated. The model was fixed using a four-hole miniplate, a six-hole miniplate, a newly designed six-hole miniplate and their curved versions. Maximum principal stress values for bone, von Mises stress values for osteosynthesis materials, and the amount of displacement between segments were measured. The highest von Mises value was observed in the curved version of the newly designed six-hole miniplate; the lowest value was detected in the four-hole curved miniplate. The lowest value of maximum principal stress in the bone was found in the curved version of the novel design six-hole miniplate. The least displacements between segments were also recorded in the new design of straight miniplate; therefore, for large mandibular advancement surgery, this novel six-hole miniplate may be a promising option with positive biomechanical characteristics.

Evaluation of bony changes observed in mandibular osteotomy lines and mandibular condyles following bilateral sagittal ramus osteotomy by fractal analysis.

This study aimed to evaluate the surgically impacted trabecular changes in mandibular osteotomy lines and mandibular condyles after bilateral sagittal split ramus osteotomy using the fractal analysis method. The study population consisted of 30 patients (9 male, 21 female) diagnosed with mandibular prognathism and operated with bilateral sagittal split ramus osteotomy under general anesthesia. Fractal analyses observed the alterations on the trabecular structure of osteotomy lines, and mandibular condyles on panoramic radiographs obtained preoperatively, postoperatively, 1st week, 6th month, and 12th month. The box-counting method was used to evaluate the changes in trabecular structure by fractal analysis. P-values of less than 0.05 were considered significant. The fractal dimension values in both osteotomy lines and mandibular condyles were significantly decreased on postoperative 1st week regarding preoperative values. However, fractal dimension values commenced increasing in the following postoperative period. The fractal dimension values of the horizontal and vertical osteotomy lines reached their preoperative values on postoperative 6th and 12th month, respectively. The decreased fractal dimension values observed in the early postoperative period in the right and left condyles reached their preoperative values at the 6th postoperative month. Fractal analyses performed postoperatively can provide information about trabecular changes and bone healing of structures such as osteotomy lines directly affected by bilateral sagittal split ramus osteotomy and indirectly affected mandibular condyles. The results support that fractal analysis can be used together with clinical data in the evaluation of bone healing process.

Craniofacial Manifestation and Orthosurgical Management of a Patient with Achondroplasia

Achondroplasia is a bone growth disorder results due to failure in endochondral ossification, conversion of cartilages into mature bones. It is the most common metaphyseal dysplastic condition of long bones. The incidence of achondroplasia is 1:25000–30,000 of live births. Our patient was a diagnosed case of achondroplasia, characterized by short stature, disproportionately short arms and legs, and short fingers. Craniofacial features include prominent forehead (frontal bossing), short cranial base, short nose, depressed nasal bridge, short upper lip leading to increased incisal show along with gingival visibility and hyperactive mentalis. Intraoral examination revealed constricted maxillary arch, multiple missing teeth, increased overjet of 12 mm, nonspecific molar, and canine relation bilaterally. Therapeutic intervention included orthosurgical management, i.e., Stage I (presurgical orthodontics)-leveling and alignment followed by closure of extraction spaces; Stage II (surgical management)–le fort-1 osteotomy and maxillary superior repositioning of 6 mm followed by 5 mm bilateral sagittal split ramus osteotomy with anticlockwise rotation of body of the mandible; and Stage III–settling of occlusion and fixed retention in maxillary and mandibular arch. Present case highlights the craniofacial manifestations of achondroplasia its effective management and the potential complications associated. Treating orthodontist should be aware of these features and their consequences in managing the patient to achieve a successful outcome.

Bad splits in bilateral sagittal split osteotomy: A retrospective comparative analysis of the use of different tools

This study aims to analyse the relationship between the incidence of bad splits and the surgical tools adopteded to perform bilateral sagittal split ramus osteotomy (BSSRO).BSSROs performed by the same experienced surgeon period were reviewed, retrospectively. The patients were divided into three groups according to the surgical instrument used to perform the osteotomy: a Lindemann burr, reciprocating saw or piezosurgery. Among the 1120 BSSROs performed, 5 bad fractures were detected during the observation period: 3 among patients operated with the Lindemann burr (0.8%) and 2 among those operated with a reciprocating saw (0.5%). There was no significant correlation between the bad split rate and age and gender of the patients, the type of malocclusion or the type of instrument used to perform the osteotomy.Within the limitations of the study it seems that the the choice of the osteotomy tool for BSSRO does not influence the rate of bad fractures and, therefore, the selection of the osteotmy tool should be left to the discretion of the surgeon.

Computed Tomography Assessment of Maxillary Sinus and Inferior Nasal Airway After Le Fort I Osteotomy.

This study aimed to evaluate and predict the factors that affect the postoperative maxillary sinus and inferior nasal cavity conditions after Le Fort I osteotomy. The rate of aerated (healthy) sinus area and the inferior nasal airway area were calculated by preoperative computed tomography measurements and at 1 week and 1 year postoperatively. Factors predicting the rate of aerated sinus area and the ratio of the inferior nasal cavity area after 1-week were examined using these variables. The subjects consisted of 112 patients (224 sides) who underwent Le Fort I osteotomy with sagittal split ramus osteotomy. The rate of aerated sinus area after 1 week was significantly correlated with sex, age, and amount of blood loss ( P < 0.0001). The rate of the inferior nasal cavity area after 1 week was significantly correlated with the anterior impaction amount of the maxilla and the preoperative rate of the inferior nasal airway area ( P= 0.0017). This study suggests that attention should be paid to females, older patients, and the amount of blood loss to prevent sinusitis, and larger maxillary impaction at the anterior site should be carefully planned to prevent severe nasal obstruction immediately after Le Fort I osteotomy.