Anterior Subapical Osteotomy Research Articles

Stability after maxillary setback by horseshoe Le Fort I osteotomy in skeletal class II cases

PurposeLe Fort I osteotomy combined with horseshoe osteotomy has been established as a technique for total maxillary setback. In this study, the stability of the maxillary and mandibular positions was examined in five cases in which was performed total maxillary setback by Le Fort I osteotomy combined with horseshoe osteotomy. Subjects and methodsThe stability of the maxilla was examined in five cases that had undergone total maxillary setback by horseshoe Le Fort I (H- LF I) osteotomy and bilateral sagittal split osteotomy (BSSO) including mandibular anterior subapical osteotomy (MASO) in one case. The changes in the position of the maxillary and mandibular positions were analyzed with lateral cephalograms taken immediately before (T0), a few days after (T1), and one year after (T2) the surgery. ResultsPostoperative maxillary changes both horizontally and vertically were all less than 2 mm. Postoperative horizontal mandibular changes showed little skeletal relapse, but all postoperative vertical mandibular changes were within 2 mm. ConclusionOur results suggest that H-LF I osteotomy is a reliable, safe, and effective surgical procedure for postoperative skeletal stability of total maxillary setback in skeletal class II cases.

Segmental mandibular advancement for moderate-to-severe obstructive sleep apnoea: a pilot study

Segmental mandibular advancement (SMA) consists of a combination of bilateral sagittal split osteotomy, anterior subapical osteotomy with extraction of the first premolars, and genioplasty, to allow an extended advancement of the mandible for the improvement of tongue base obstruction in moderate-to-severe obstructive sleep apnoea (OSA) and to minimize any unfavourable aesthetic change due to the large jaw advancement. The aim of this pilot study was to evaluate the surgical outcomes and complications following SMA in OSA patients. Twelve patients (nine male, three female) underwent SMA as part or whole of their skeletal advancement procedure for OSA. The apnoea–hypopnoea index (AHI) improved from a mean± standard deviation 42.4 ± 22.0/hour preoperatively to 9.0 ± 17.4/hour at 1 year postoperative. Surgical success (50% reduction in AHI) was achieved in 11 of the 12 patients (91.7%) at 1 year postoperative, while seven patients (58.3%) attained surgical cure (AHI<5/hour). The lowest oxygen saturation (LSAT) increased from a mean 73.3% preoperatively to 78.7% at 1 year postoperative. The airway volume increased from a mean 2.4 ± 1.7 cm3 at baseline to 6.7 ± 3.5 cm3 at 1 year postoperative (P < 0.001). No major complication occurred. This pilot study showed that SMA appears to be safe and effective as part or whole of the skeletal advancement surgery for moderate-to-severe OSA.

What are the surgical risks and 2-year stability of mandibular anterior subapical osteotomy in the treatment of dentoalveolar protrusion?

To investigate the stability and complications of mandibular anterior subapical osteotomy (ASO) in the treatment of bimaxillary dentoalveolar protrusion by way of a retrospective study. One hundred and twenty patients who received orthognathic surgery at a single center between 2008 and 2017 were included. Relapse was assessed by serial tracings of lateral cephalograms which were obtained pre-operatively (T1), within 6weeks after surgery (T2) and at 2years after surgery. The changes between T2 and T3 represented stability and were tested using the paired t test. The relationship between the extents of surgical repositioning (T2-T1) and relapse (T3-T2) was investigated using the Pearson correlation coefficient. The associations between the variables and the occurrence of relapse and complications identified the risk factors and were evaluated using the χ2 test or Fisher's exact test. When r > 0.80, clinical correlation was considered significant; and statistical significance was set at P < 0.05, while confidence interval was set at 95%. There was a mean uprighting of L1-MP by 12.7°. At 2years after surgery, 96.7% of the patients experienced a mean relapse of L1-MP by 2.9°. The extent of surgical repositioning was only weakly correlated with that of relapse and no specific factor that increased the risk of relapse could be identified. The most frequent complications were blood loss requiring transfusion, wound dehiscence or infection, gingival recession, and periodontal bone loss, involving 25.8 to 43.3% of the patients. The remaining complications included tooth root damage, fixation hardware exposure or infection, lingual mucosal laceration, and tooth devitalization. There were no cases of avascular necrosis or nonunion. Although relapse occurred in most of the patients after 2years, the actual extent was small (2.9°) which was not likely to be clinically significant. HKUCTR-2964 CLINICAL RELEVANCE: Although ASO may be valuable in correcting mandibular dentoalveolar protrusion, the procedure brings with it risks and complications and should be reserved for severe deformities.

Accuracy of mandibular anterior subapical osteotomy by virtual planning in orthognathic surgery using patient-specific implants

IntroductionMandibular anterior subapical osteotomy (MASO) is a complementary procedure during orthognathic surgery to correct proclination or extrusion of the anterior incisors when orthodontic movements fail. The increasing use of patient-specific implants (PSI, titanium plates) in orthognathic surgery has extended to this procedure. Digital orthognathic surgery planning involves manufacturing cutting/drilling guides and specific implants to provide better accuracy and allow complex movement with reduced surgical times compared to conventional planning. This study aimed to assess the accuracy of computer-aided surgery with patient-specific implants in mobilising the MASO segment according to planning. MethodsEleven consecutive patients with mean age 26.82 years (15–41, SD = 10.65) were treated with MASO in addition to other conventional orthognathic procedures incorporating digital planning and patient-specific implants. A three-dimensional “stl” format file of the mandibular dental arch was obtained using an intraoral scanner at the end of the surgical procedure. The accuracy of the MASO segment displacement imposed by PSI was assessed by comparing preoperative 3D-planned mandibular dental arch with the immediate postoperative 3D-measured arch, using surface superimposition and 7 standard dental landmarks. Deviations between the preoperative and postoperative landmarks were calculated and compared to determine whether MASO segment repositioning is sufficiently accurate to be safely used to reposition the incisor/canine axis. ResultsQuantitative analysis revealed an absolute linear difference of 0.66 mm (SD = 0.51) between preoperative 3D digital dental arch impression and postoperative planned 3D dental arch. Overall, the median absolute discrepancies in the x-axis (right-left direction), y-axis (antero-posterior direction), and z-axis (supero-inferior direction) were respectively 0.56 mm (SD = 0.42), 0.77 mm (SD = 0.45) and 0.65 mm (SD = 0.61). ConclusionA high degree of accuracy between the virtual plan and the immediate postoperative result was observed. According to our results, PSI can be used safely with accuracy in MASO as an adjunct to other conventional orthognathic procedures.

Reciprocating Rasp for Use in Mandibular Anterior Subapical Osteotomy.

The article describes a reciprocating rasp used in the mandibular anterior subapical osteotomy. Over the past 2 years, reciprocating rasp osteotomy was introduced in the Oral and Craniomaxillofacial Surgery Department of Shanghai Ninth People's Hospital. No complication such as bleeding, wound infection, or tissue necrosis has been encountered. The use of reciprocating rasp avoids iatrogenic damage to adjacent structures and reduces the time spent operating mandibular anterior subapical osteotomy. Therefore, it is recommended for mandibular anterior subapical osteotomy.

The Envelope of Segmental Movement and Airway Changes After Mandibular Anterior Subapical Osteotomy in Skeletal Class II Protrusion Patients.

This study aimed to determine the envelope of anterior segmental movement and changes in the inferior pharyngeal airway space (IPAS) and position of the hyoid bone following mandibular anterior subapical osteotomy (ASO) under local anesthesia in skeletal Class II patients with protrusion. The subjects were 33 skeletal Class II adult patients with lip protrusion. They were treated by extraction of 4 premolars and mandibular ASO under local anesthesia. Surgical movement of mandibular anterior segment and IPAS after surgery was evaluated by mandibular superimposition using lateral cephalograms between before and immediately after surgery. The depth of osteotomy and overlapping ratio were measured. The mean retraction of the mandibular incisor was 4.04 mm at the tip and 4.29 mm at the root apex. The mean vertical movement of the mandibular incisor was 3.33 mm intrusion at the tip and 3.42 mm at the root apex. The axis of the mandibular incisor did not change significantly. Patients with deep curve of Spee showed significantly more intrusion of incisors, whereas the incisor axis became more proclined. The IPAS became narrower, and the hyoid bone moved downward after surgery. The decreased IPAS was positively correlated with retraction of root apex and proclination of the mandibular incisors. To establish precise surgical treatment objectives, a balance between the amount of intrusion and changes in axis should be sought after considering anatomical limitations. Mandibular ASO should be performed with caution in skeletal Class II patients vulnerable to airway-related problems.

Comparison of intraoperative blood loss between four different surgical procedures in the treatment of bimaxillary protrusion

This study was aimed at investigating the correlation between intraoperative blood loss and operation-related factors in the treatment of bimaxillary protrusion with four different procedures. Ninety-four patients were separated into the following four surgical groups: group 1: anterior subapical osteotomy of the maxilla (ASO Mx)+bilateral parasymphyseal osteotomy of the mandible (BPsO Md)+genioplasty (GeP); group 2: ASO Mx+BPsO Md; group 3: ASO Mx+ASO Md+GeP; and group 4: ASO Mx+ASO Md. Patient- and operation-related factors (age, intraoperative blood loss, operation time, and preoperative and postoperative blood parameters) were compared among the four groups. The mean operation time and intraoperative blood loss were 438.7minutes and 369.9mL in group 1; 432.5minutes and 356.5mL in group 2; 393.3minutes and 387.3mL in group 3; and 353.5minutes and 289.5mL in group 4. Intergroup differences in intraoperative blood loss were not significant. A significant correlation between intraoperative blood loss and operation time was found in group 4 but not in the other groups. No significant differences in blood loss were found among the four different surgical procedures in the treatment of bimaxillary protrusion.

Combining the Anterior Subapical Osteotomy With Traditional Orthognathic Surgery

The anterior sub-apical osteotomy (ASO) is a valuable procedure in the treatment of certain dentoskeletal deformities. Kole popularized the mandibular ASO in 1959. It can be used in the maxilla and mandible often in conjunction with extraction of premolars. This technique has been performed on its own for correction of dentoalveolar protrusion as well as skeletal-dental open bite and deep bite deformities while maintaining chin position and improving labiomental relationships. It can also be used in combination with Le Fort I (LFI) and bilateral sagittal split osteotomies (BSSO) with benefits including improved lip relations and labiomental esthetics, chin contour and incisor proclination. In addition, it is well known that large mandibular setbacks can increase the likelihood of airway compromise and the mandibular ASO can circumvent the need for large posterior repositioning. The purpose of this study is to present the utility of combined mandibular ASO with the LFI, BSSO and maxillary ASO as an approach for addressing certain dentoskeletal deformities. This study includes 13 patients (4 male, 9 female) of an average age of 19.8 years (range 13 to 28 years), 7 with clefts, 1 Crouzon syndrome and 5 dentoskeletal deformities. Six patients underwent mandibular ASO and LFI; 4 underwent mandibular ASO, LFI and BSSO; 2 patients underwent bi-maxillary ASO, and 1 maxillary ASO and BSSO. All procedures were completed by a single surgeon (JWP). The patients were followed a minimum of 2 years after surgery. Cephalometric changes before and after surgery were analyzed using a paired t test (p<0.05). The results demonstrated a favorable improvement in the mandibular incisor to mandibular plane angulation, increased distance between pogonion and the tip of the lower incisor, decreased distance of the lips to the esthetic line and increase in the depth of the labiomental fold. Based on the measured parameters all patients had an improvement in their skeletal, dental and soft tissue relations. The combination of the mandibular ASO with other maxillary and mandibular osteotomies is a useful surgical option in the treatment of certain dentoskeletal deformities.

Evaluation of neurosensory disturbance following orthognathic surgery: a prospective study.

The prospective study was to evaluate the incidence, type of neurosensory disturbance (NSD), grade its severity and monitor its recovery occurring in the lower lip and chin due to damage to inferior alveolar nerve following orthognathic surgery involving mandible. The study included 10 patients who have undergone sagittal split osteotomy, genioplasty, and anterior subapical osteotomy (ASO). All the patients examined preoperatively and post operatively 1week, 1 and 6months according to standardized test to clarify the subjective and objective neurosensory status of the injured nerve. Pin prick test, blunt test, two-point discrimator test, brush stoke direction, light touch test, warm and cold test were used bilaterally to lower lip and chin area. Seven patients underwent bilateral sagittal split osteotomy (BSSO) (70%), one patient had BSSO with genioplasty (10%), two patients had BSSO with ASO (20%). During the operation none of the nerves were transectioned, in 60% of patients nerve was not visible and in 40% of patients nerve was seen in distal segment. 70% of patients underwent setback, 30% of patients underwent advancement. The subjective evaluation of the patients revealed the incidence of 90% at 1week, 30% at 1month, 20% at 6months and 10% at 1year post operatively. The altered sensation reported subjectively was hypoesthesia in 50% of the patients, anaesthesia in 40% of the patients. There was 100% recovery in advancement cases and 93.5% recovery in setback cases. There is a high incidence of NSD of the lower lip and chin after BSSO related to advancement, setback, intraoperative nerve encounter and surgical skill. However, recovery of sensation occurs with increasing frequency during the follow-up period. The clinical neurosensory tests are effective guides to study the neurosensory deficit.

Systematic Analysis of Clinical Outcomes of Anterior Maxillary and Mandibular Subapical Osteotomy With Preoperative Modeling in the Treatment of Bimaxillary Protrusion

The purpose of this study was to determine the changes in teeth and hard tissues after preoperative modeling and bimaxillary anterior subapical osteotomy for the treatment of bimaxillary protrusion. Cephalometric analysis was used to evaluate the aesthetic effects and occlusal relationships obtained. The subjects included 19 women and 1 man (aged 19-41 years; average, 29 years) with bimaxillary protrusion who underwent anterior subapical osteotomy of both the maxilla and mandible, with simultaneous genioplasty, if required. Based on a preoperative computer-aided manufacturing/design-assisted and model surgical design and an occlusal guide plate, new occlusal relationships were established for the patients. In addition, the preoperative and postoperative cephalometric radiographs were systematically analyzed. In all patients, the surgical incisions underwent primary healing, with no infection or osteonecrosis. Significant differences were observed in the preoperative and postoperative values of all hard tissue and teeth parameters, except for SGn-FH degrees and Co-MP. The most obvious significant differences were seen in L1-OP°, Id-Pog-Go°, IIA°, U1E-Apog, L1E-Apog, U1E-NA, and L1-NA° (P < 0.001). Postoperative follow-up lasted for 12 to 36 months. All patients eventually achieved normal jaw relationships, tooth arch forms, and Spee curves. No evident irregularities of teeth arrangement or abnormal occlusal relationships were observed. All patients were satisfied with their postoperative facial appearance, except for 1 patient, who underwent repeat surgery because of relapse. With the use of a precise preoperative model surgical design, orthognathic surgery, a simple and time-saving technique, can be used to correct bimaxillary protrusion with satisfactory postoperative occlusal relationship and facial aesthetic appearance and minimal postoperative complications.

下顎前歯部歯槽骨切り術・オトガイ形成術施行後に癒合不全を呈した下顎前突症の１例

A 40-year-old female visited our department in June 2008 with chief complaints of intraoral denudation of the canine root, occlusion anomaly, and mastication disorder. She had a history of mandibular anterior subapical osteotomy and genioplasty by removal of the mandibular margin of the mental region under general anesthesia in another hospital in June 2007. In December 2007, an aperture was found at the osteotomy site and plate fixation was performed in the same hospital in January 2008. However, denudation of the canine root was found in February 2008 with a mastication disorder that had persisted since the initial surgery, which led her to visit to our department.At her initial visit, denudation of the canine root was confirmed. The right molars were missing and no contact was found in the anterior teeth. Skin mobility in the mental region was limited, indicating oral food intake without mastication. The patient was diagnosed as fissure fracture of the mandibular bone at the distal region of the lower left canine and faulty union of the alveolar osteotomy site.Alveolar osteotomy was repeated and the mandibular fracture was fixed under general anesthesia in September 2008. The cortical bone of the former alveolar osteotomy site showed faulty union. Following repeated osteotomy, the dentures were reconstructed by supporting them with preoperatively prepared plate splints and wire splints to check the occlusion, and then the osteotomy site was fixed with a miniplate. Iliac bone was grafted in the bone gap, and intermaxillary anchorage was retained for 20 days postoperatively. Following treatment, the occlusion in the anterior teeth improved and the patient was able to take regular food. However, continuous follow-up is necessary because of persistent partial denudation of the canine root and denudation of the grafted bone.In the diagnosis and treatment of jaw deformities to correct occlusion and masticatory functions, we consider that preoperative and postoperative occlusal management is important, especially when it appears to be difficult to obtain stability of postoperative occlusion.

術前矯正治療にオトガイ形成術と下顎前歯部歯槽骨切り術を併用した下顎後退症の１例

It is not always simple to treat maxillary protrusion cases with marked labially inclined mandibular incisors and mandibular retrognathia. Optimal front teeth inclination, along with a proper maxillo-mandibular relation is a key factor in obtaining postsurgical longterm stability. When treating such cases, mandibular advancement only by sagittal ramus osteotomy does not lead to pertinent incisor angle at all, and hence it is crucial to improve incisor angle by other means. On such occasions, especially in narrow mandibular symphysis, the root exposes from the surface of the alveolar bone following axial improvements by ordinary orthodontic treatment. Meanwhile, anterior subapical alveolar osteotomy results in no bone contact to the basal stump of the segment, leading to poor alveolar segment stability. Therefore, we considered various treatment modalities of such condition, and finally used the following strategy. Namely, we performed genioplasty in the early stage of the presurgical orthodontic treatment to lay the infrastructure for the subsequent forward root movement. Following bone union at the osteotomy site, we secondarily carried out mandibular anterior subapical alveolar osteotomy to improve the axis of the incisors. After completing the presurgical orthodontic treatment, we performed Le Fort I and sagittal split ramus osteotomies to achieve a functional maxillo-mandibular relation. Improvements in angle measurements before presurgical and after postsurgical orthodontic treatment were: L1-Mn 92.0 improved to 81.5 degrees; L1-Oc 32.5 to 19.5; and interincisal angle improved from 111.0 to 131.5. We consider this method to be fascinating and outline of the representative case in this report.

Esthetic management of extraction sites delayed to immediate loading protocols

will continue to undergo modifications and change in an effort to improve the quality of patient care and outcome. This program will present newer treatment approaches and technical modifications, as well as the clinical and research results substantiating the efficacy of these surgical methods. The following modifications will be discussed: 1. Genioplasty A. Porous block HA and HTR augmentations B. Tenon and mortise osseous genioplasty 2. Anterior mandibular subapical osteotomy 3. Mandibular body osteotomy A. Anterior B. Posterior 4. Mandibular ramus sagittal split modifications A. Ramus and inferior border osteotomy B. Rigid fixation 5. Maxillary osteotomy modification A. Maxillary step osteotomy and rigid fixation B. Porous block HA grafting 6. Double jaw surgery A. Selective alteration of the occlusal plane B. Surgical sequencing of the maxilla and mandible C. Model surgery modifications 7. Simultaneous orthognathic surgery and rhinoplasty A. Surgical sequencing B. Rhinoplasty techniques Implementation of these techniques by the experienced, skilled surgeon, coupled with accurate diagnosis and treatment planning, should provide optimal functional and esthetic outcomes for our patients.

A comparison of profile changes between ramus and anterior mandibular subapical osteotomies in class III Chinese patients

The purpose of this study was to compare cephalometrically the differences in soft-tissue profile changes produced by intraoral ramus and anterior subapical osteotomies for the treatment of Chinese patients with class III malocclusion. Thirty-seven Chinese adults whose class III malocclusion was treated either with an intraoral ramus (group A) or an anterior subapical (group B) osteotomy were selected for the study. Serial lateral cephalograms taken presurgically (T1) and at least 6 months postretention (T2), showed marked improvement in the soft-tissue profile in both groups. Although the percentage response of soft- to hard-tissue movement was similar at lebrale inferius, the response at soft-tissue point B was found to be statistically less in group B than in group A ( P < .05). Although the correlation between the upper lip response to mandibular ramus setback in group A was weak (r = 0.11), there appeared to be a relatively strong correlation between posterior movement of the upper lip and the magnitude of the lower segmental setback (r = 0.65). The differences in soft- to hard-tissue response with the two osteotomy procedures appear to vary with those reported in whites. This study emphasizes the need for different prediction ratios of soft- to hard-tissue movement in different racial types.

The versatility of genioplasty using a broad pedicle

The biologic and clinical foundation for using a broad soft-tissue pedicle genioplasty technique is described. This technique is versatile and stable and produces more predictable soft-tissue changes than previously reported methods of altering chin contour with alloplastic implants. The broad pedicle genioplasty technique has clear advantages over other techniques for procedures such as secondary genioplasty using local anesthesia, concomitant genioplasty and anterior subapical osteotomy, simultaneous genioplasty and submental lipectomy, and segmentalization of the chin to facilitate narrowing or widening.

Subapical osteotomy to increase mandibular arch length

Anterior mandibular subapical osteotomy offers an alternative method of managing selected malocclusions which are associated with minimal to moderate crowding. Persons with a Class II deep bite, dentoalveolar retrusion, normal chin prominence, and deep labiomental fold are potentially good candidates for such treatment. The mandibular anterior teeth are surgically repositioned anteriorly to increase arch length, facilitate postsurgical orthodontic treatment of crowded and malaligned teeth, and obviate the need for extractions. Additional soft-tissue facial support is gained from the advanced dento-osseous segment. The anterior mandibular alveolar segment is moved fotward the distance which, calculated from a Bolton analysis and diagnostic orthodontic setup, is necessary to align the teeth. Careful preoperative occlusal analysis and planning by the surgeon and the orthodontist are essential to select the appropriate interdental osteotomy site and determine the feasibility of the surgical plan. To date, vertical interdental osteotomies have been made only in the canine-lateral incisor or canine-first premolar interspaces. Mandibular subapical osteotomy-surgery technique For this procedure, the patient is usually placed under general nasoendotracheal anesthesia. When, however, only the incisor teeth are to be repositioned, the surgery is easily carried out with only local anesthesia. A local anesthetic agent with vasoconstrictor is infiltrated into the mental symphysis region for hemostasis. The incision for the anterior mandibular subapical osteotomy is designed to maintain circulation to the lingual and labial aspects of the mobilized dental osseous segment (Fig. 1). Anteriorly, the incision is made through the lower lip mucosa above the labial frenum, midway between the depth of