Vertical Ramus Osteotomy Research Articles

Salvation for Hardware Failure of Resorbable Fixation Plates in Bilateral Mandibular Angle Fractures

The resorbable fixation system is used for the treatment of facial bone fractures and has many merits. It does not require a fixture removal procedure and is biologically nontoxic. Also, it does not disturb normal growth in growing children. However, there are also many points to be considered, such as resorption time, foreign body reaction, infection rate, or fixation stability depending on the fracture pattern. Because of these factors, there is still controversy over the use of a resorbable system.We present a case of a patient who experienced malunion after using a resorbable fixation system to treat bilateral mandibular angle fracture, which was recovered by corrective osteotomy and vertical ramus osteotomy in our department.

Recovery Pattern of Mandibular Movement by Active Physical Therapy After Bilateral Transoral Vertical Ramus Osteotomy

The purpose of the present study was to evaluate the effect of an active physical therapy (PT) protocol after transoral vertical ramus osteotomy and to investigate the rehabilitation patterns of mandibular movement. The study included 187 patients diagnosed with mandibular prognathism with or without facial asymmetry who had undergone bilateral transoral vertical ramus osteotomy from 2001 to 2009. The subjects were evaluated preoperatively and 1, 3, 6, 12, 18, and 24 months postoperatively in terms of the periods of PT and range of mandibular movement. The data were analyzed using 1-way analysis of variance (significance level, P < .05). Of the 187 patients, 108 (57.8%) did not receive repeat intermaxillary fixation (IMF) during the PT period, 58 (31.0%) received it once, 15 (8.0%) twice, and 6 patients more than 3 times. The average PT period for all was 10.9 days (range 5 to 45). The mean maximal mouth opening was 50.7 mm before surgery, decreasing to 33.9 mm at 1 month postoperatively. This was followed by an increase to 46.3 mm at 6 months postoperatively, with the maximal mouth opening thereafter showing 93.9% to 95.7% recovery compared with the preoperative state. About 88% of the patients with transoral vertical ramus osteotomy responded well to the reduced IMF duration and active PT protocols, receiving repeat IMF less than twice. It required about 6 months to recover 90% of the preoperative maximal mouth opening and 12 months to recover near preoperative levels statistically. The benefits of reduced IMF duration and the PT protocols seem to promote rehabilitation of the masticatory muscles and prevention of mandibular hypomobility.

Treatments for adults with prominent lower front teeth

Prominent lower front teeth may be associated with a large or prognathic lower jaw (mandible) or a small or retrusive upper jaw (maxilla). Edward Angle, who may be considered the father of modern orthodontics, classified the malocclusion in this situation as Class III. The individual is described as having a negative or reverse overjet as the lower front teeth are more prominent than the upper front teeth. The purpose of this systematic review was to evaluate different treatments of Angle Class III malocclusion in adults. The following databases were searched: Cochrane Oral Health Group Trials Register (to 22 March 2012); CENTRAL (The Cochrane Library 2012, Issue 1); MEDLINE via OVID (1950 to 22 March 2012); EMBASE via OVID (1980 to 22 March 2012); LILACs (1982 to 22 March 2012); BBO (1986 to 22 March 2012); and SciELO (1997 to 22 March 2012). All randomized or quasi-randomized controlled trials of treatments for adults with an Angle Class III malocclusion were included. Three review authors independently assessed the eligibility of the identified reports. Two review authors independently extracted data and assessed the risk of bias in the included studies. The mean differences with 95% confidence intervals were calculated for continuous data. Two randomized controlled trials were included in this review. There are different types of surgery for this type of malocclusion but only trials of mandible reduction surgery were identified. One trial compared intraoral vertical ramus osteotomy (IVRO) with sagittal split ramus osteotomy (SSRO) and the other trial compared vertical ramus osteotomy (VRO) with and without osteosynthesis. Neither trial found any difference between the two treatments. The trials did not provide adequate data for assessing effectiveness of the techniques described. There is insufficient evidence from the two included trials, to conclude that one procedure is better or worse than another.The included trials compared different interventions and were at high risk of bias and therefore no implications for practice can be given.Further high quality randomized controlled trials with long term follow-up are required.

Transverse and sagittal angulations of proximal segment after sagittal split and vertical ramus osteotomies and their influence on the stability of distal segment

This study aimed at comparing the transverse and sagittal angulations of proximal segment after sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO), and examining their influences on the stability of distal segment. Patients who received SSRO (n = 21) or IVRO (n = 11) for mandibular setback were included. Lateral and posteroanterior cephalograms taken within 1 month before surgery (T1), within 1 week after surgery (T2), and at least 6 months after surgery (T3) were analyzed. The angulation of each proximal segment relative to the upper orbital margin line was measured on posteroanterior cephalogram and the sum of both angles (total ramus angle, TRA) was obtained. On lateral radiograph, ramus inclination angle (RIA) relative to a horizontal reference line 7° to the sella-nasion was assessed and B-point position was measured. From T1 to T2, more increases in TRA and RIA were noted after IVRO than after SSRO. From T2 to T3, TRA and RIA significantly decreased in IVRO group but remained relatively stable in SSRO group. ΔTRA(T1-T2) positively related to upward rotation of distal segment for SSRO and downward rotation for IVRO from T2 to T3. For SSRO only, ΔRIA(T1-T2) significantly related to forward movement of distal segment during remodeling. TRA and RIA increase significantly after IVRO and then regress, whereas they increase mildly after SSRO and remain stable. Increase in TRA significantly relates to distal segment rotation during remodeling for both surgeries, but increase in RIA relates to forward relapse of the distal segment only for SSRO. The reasons underlying the correlations are not certain and deserve future investigations.

Effects of Patient- and Operation-Related Factors on Postoperative Pain After Orthognathic Surgery

This study aimed to assess the association between patient- and operation-related factors and postoperative pain in patients undergoing intraoral vertical ramus osteotomy (IVRO) or IVRO + genioplasty (GeP) for the treatment of mandibular prognathism. A visual analog scale (VAS) was used to evaluate postoperative pain for 2 days in 63 patients who underwent orthognathic surgery (42 IVRO and 21 IVRO + GeP). Correlations between VAS and patient age, sex, blood loss, operation time, and intraoperative reduction in blood parameters were assessed and compared between IVRO and IVRO + GeP procedures. Mean operation time and blood loss were 252.02 minutes and 99.64 mL in the IVRO group and 317.62 minutes and 187.86 mL in the IVRO + GeP group, respectively. Operation time, blood loss, and postoperative reduction in blood parameters were significantly greater in the IVRO + GeP group than in the IVRO group. Mean VAS scores on the first and second postoperative days were 3.02 and 1.33 in the IVRO group and 2.95 and 1.14 in the IVRO + GeP group. However, postoperative pain did not differ significantly between the IVRO and IVRO + GeP groups on the first or second postoperative day. Postoperative pain associated with orthognathic surgery was acceptable, controllable, and not different between IVRO and IVRO + GeP procedures.

Preliminary study of condylectomy via intraoral approach

Condylectomy was performed to treat condylar osteoma or hyperplasia. Introduced two methods of condylectomy via intraoral approach and evaluated their clinical results. Thirty-five patients, aging from 22 to 57.21 years, were treated by condylectomy via intraoral approach, of which 21 were condyle osteoma, 14 hemimandibular hyperplasia and condylar hyperplasia. Intraoral vertical ramus osteotomy (IVRO) were used in 32 patients and intraoral condylectomy via coronoid process resection was used in 3 patients. The treatment results including oral function and facial symmetry after the operation were good in all patients. The temporomandibular joint (TMJ) dysfunction syndrome alleviated or disappeared. The follow-up period was 6 months to 3 years, and no relapse of condylar osteoma or hyperplasia was found. The patients who had IVRO and TMJ reconstruction had some degree of transplanted bone resorption, and one patients had relapse of facial deformity. But the patients who had intraoral condylectomy via coronoid process resection only had mild condyle remodeling and no obvious bone resorption was noted. The two methods of intraoral condylectomy introduced in this stugy can successfully correct the facial deformity and TMJ dysfunction caused by condylar osteoma or hyperplasia. But the surgeons need to have excellent surgical skills and careful selection of the indications.

Masseter muscle changes following orthognathic surgery

To evaluate the long-term changes of masseter muscle morphology in skeletal Class III patients with facial asymmetry following two-jaw orthognathic surgery (Le Fort I osteotomy + intraoral vertical ramus osteotomy). Using computed tomography (CT), a longitudinal study was conducted on 17 skeletal Class III patients with facial asymmetry. Measurements from the reconstructed three-dimensional (3D) CT images were compared from T1 (before surgery), T2 (1 year after surgery), and T3 (4 years after surgery). The maximum cross-sectional area (CSA), orientation, thickness, and width of the masseter muscle were measured on both the deviated and nondeviated sides. The control group included 17 volunteers with skeletal and dental Class I relationships without dentofacial deformities. At T1, there were no significant differences in CSA, thickness, or width of masseter muscle between the deviated and nondeviated sides. Masseter muscle orientation was significantly more vertical on the nondeviated side than on the deviated side at T1 (P < .01); no significant bilateral differences were noted at T2 and T3. At T1, masseter muscle measurements were significantly lower than controls (P < .01). During T1-T3, a significant increase was noted in CSA, thickness, and width (P < .01) of masseter muscle. At T3, no significant difference was noted between the study and control groups. After surgery, the masseter muscle measurements of skeletal Class III asymmetry patients showed no significant differences compared with the control group within the 4-year follow-up period, indicating adaptation to the new skeletal environments and increased functional demand.

Soft-tissue profile changes after orthognathic surgery of mandibular prognathism

During surgical correction of facial deformities, accurate prediction of the resulting facial profile is important for the patient and the surgeon. The purpose of the present study was to investigate profile changes after surgical treatment of mandibular prognathism. Thirty patients (20 females and 10 males; ages 17–28 years) with mandibular prognathism underwent vertical ramus osteotomy. Preoperative and postoperative cephalograms were analyzed; landmarks were identified and compared. The mean horizontal setback of the pogonion (Pog) was 11.7mm. The setback ratios of labrale inferius (Li)/incision inferius (Ii), labiomental sulcus (Si)/point B, and soft tissue pogonion (PogS)/pogonion (Pog) were 0.98, 0.99, and 0.95, respectively. There were no sex-related changes in soft tissue. These findings indicate that changes in soft tissue closely correlate with the amount of mandibular setback in the horizontal direction. Such information might facilitate more accurate prediction of the outcome of orthognathic surgery.

Revisiting the Boyne procedure

BackgroundThe technique involving the free grafting of the mandibular condyle with a vertical ramus osteotomy was described by Philip Boyne in 1987 along with a series of 15 cases where a patient presented with a markedly displaced fracture dislocation of the mandibular condyle. MethodTwenty-one cases (25 condylar fractures) were treated with a modified Boyne technique. ResultsResults showed that we had a complication rate of 12% (8% resorption, 4% fracture of the plate). ConclusionThe Boyne procedure should be thought of as a mainstream treatment method for the displaced fractured mandibular condyle.

Soft and hard tissue changes after bimaxillary surgery in Japanese class III asymmetric patients

Objectives:To assess the effects of bimaxillary surgery on Class III subjects with mandibular asymmetry, and to compare the effects of the type of surgery performed in the mandible on the facial profile especially in the presence of facial asymmetry.Materials and Methods:Thirty-six patients in whom imbalance between the maxilla and the mandible were corrected by Le Fort I osteotomy combined with bilateral intraoral vertical ramus osteotomy (BIVRO group, n=9), bilateral sagittal split ramus osteotomy (BSSRO group, n=14), or a combination of intraoral vertical ramus osteotomy (IVRO) and sagittal split ramus osteotomy (SSRO) (IVRO + SSRO group, n=13). Cephalograms were taken before surgery (T1), and 1 year after surgery (T2). Hard and soft-tissue changes were compared.Results:The postsurgical findings showed that greater mandibular backward displacement and greater upper lip forward movement were more pronounced among BIVRO group when compared with BSSRO group. Upper lip relation to E-line showed greater improvement in BIVRO group than BSSRO and IVRO + SSRO groups. The ratios of corresponding mandibular soft to hard tissue movements were higher than that of maxillary movements and were more pronounced in IVRO + SSRO and BSSRO groups when compared with BIVRO group.Conclusion:IVRO surgical technique appears to be more effective in positioning the mandible more posteriorly and improving upper and lower lips position and competence.

Observation of Osseous Healing after Intraoral Vertical Ramus Osteotomy (IVRO)

Intraoral Vertical Ramus Osteotomy (IVRO) is frequently performed as a form of mandibular osteotomy, but the process of osseous healing of the split bone fragments has not yet been reported. The purpose of this study was to clarify the process of osseous healing occurring in the tissue over time. The subjects were 35 patients who underwent IVRO. Sixty-one rami from these patients were studied at 1 month, 6 months, 1 year, and then 2 to 3 years after surgery by computed tomography (CT) . The plane passing through the mandibular foramen was designated as the upper plane, while the plane passing through the root furcation was designated as the lower plane. We examined all of the images between the two planes. We classified 5 types of bone fragments, from proximal to distal; these were classified on the basis of the CT cross- sectional images at 1 month after surgery. The 5 types were as follows: outer-side type (OS) , outer-proximal type (OP) , proximal type (PX) , inner-proximal type (IP) , and inner-side type (IS) . To elucidate the types of osseous healing, the progression of bone formation and the forms of the mandibular ramus proximal bone fragments were examined. In most cases, bone fragments were covered with callus-like structures at 6 months after surgery, and changed to cortical bone-like structures at 2 to 3 years after surgery. That is, the split bone fragments were in a transitional state at 2 to 3 years after surgery. In the majority of cases, the forms of the mandibular ramus proximal bone fragments were PX and OP. OP showed a significant difference in the amount of setback of the distal bone fragment. These aspects of osseous healing were discussed mainly because of the clinical importance of postoperative mouth opening and closing and the traction of the surrounding soft tissue.

顎変形症の標準手術 － Le Fort I 型骨切り術－

Othognathic surgery for jaw deformities are most frequently performed in Japan. Regarding those procedures, Le Fort I osteotomy and anterior maxillary alveolar osteotomy in the maxilla, and sagittal split ramus osteotomy, intraoral vertical ramus osteotomy, anterior mandibular alveolar osteotomy, and genioplasty in the mandibule are selected singly or combined based on cases. Among these orthgnathic surgeries, Le Fort I osteotomy is a typical surgical procedure, as well as sagittal split ramus osteotomy. Although the designing of osteotomy lines in Le Fort I osteotomy is simple, this surgical procedure is apt to be regarded as difficult, due to other risk factors in comparison with mandibular osteotomy, such as difficulty in the repositioning of bone segment, complexity of the maxillary bone structure, bleeding, surgical invasion of the nasal cavity and paranasal sinus, and postoperative changes in the nasal base morphology. However, regarding surgical treatment for jaw deformities, Le Fort I osteotomy is considered to be a surgical procedure which we should master, as well as sagittal split ramus osteotomy.Basically, orthognathic surgeries involve subperiosteal surgical manipulation, and it is simply summarized that Le Fort I osteotomy should also be carefully performed without injuring the periosteum. In order to achieve this, it is necessary to accumulate experience, sufficiently understanding the basic factors to safely perform Le Fort I osteotomy. This manuscript outlines the major points in the surgical procedure of Le Fort I osteotomy.

Osteomark: a surgical navigation system for oral and maxillofacial surgery

The purpose of this project was to test a surgical navigation tool designed to help execute a surgical treatment plan. It consists of an electromagnetically tracked pencil that is used to mark bone intraoperatively. The device was tested on a precision block, an ex vivo pig mandible and during performance of six endoscopic vertical ramus osteotomies on pig cadavers. The difference between actual pencil position and that displayed by the computer was measured three times each at ten 2mm holes on the block (n=30 observations) and on the ex vivo mandible (n=11 measurements). Errors between planned and actual osteotomy locations for the cadaver procedures were measured. The mean distance between known and displayed locations was 1.55±0.72mm on the precision block and 2.10±0.88mm on the pig mandible. The error measured marking the same point on the block multiple (n=5) times was 0.58±0.37mm. The mean error on the simulated osteotomies was 2.35±1.35mm. Osteomark was simple to use and permitted localisation of holes and osteotomies with acceptable accuracy. In the future, the device and algorithms will be revised to further decrease error and the system will be tested on live animals.

Anatomic study of the mandibular foramen, lingula and antilingula in dry mandibles, and its statistical relationship between the true lingula and the antilingula

The authors verified the anatomical location of the mandibular foramen, lingula and antilingula in dry mandibles, aiming to obtain information that could be used when performing mandibular osteotomies. Forty-four mandibles (88 sides) were evaluated. The distances were measured using a sliding calliper, with the mandibles fixed in a reproducible position. Results showed that the mandibular foramen is on average 5.82 mm below the lingula. Regarding the statistical comparison between the mandibular foramen entrance and the antilingula position, there is no correlation between the position of those two structures in the studied sample. The mandibular foramen is slightly posterior in relation to the centre of the ramus. The lingula is an important anatomic landmark for ramus surgery, and for determining the distance to the mandibular foramen entrance. The use of the antilingula as a landmark for the position of the vertical ramus osteotomy is not recommended.

下顎枝垂直骨切り術 (IVRO) に関する臨床的研究

Intraoral Vertical Ramus Osteotomy (IVRO) is becoming widely used for correction of mandibular skeletal deformities in Japan.The purpose of this study was to investigate the postoperative change of the proximal segments after bilateral IVRO. Retrospective radiographic assessments were performed for fifteen patients with mandibular prognathism who had been corrected surgically by bilateral IVROThe results were as follows:1. On lateral cephalometric analysis, the ramus inclination increased at one week after surgery and decreased gradually during one year.2. On posteroanterior cephalometric analysis, Gonia showed lateral displacements at one week after surgery and returned internally during one year.3. The condyles moved anteroinferiorly after surgery.

Changes in the Transverse Dimensions by Vertical Ramus Osteotomy After Mandibular Prognathism Correction

A harmonious face displays not only a good lateral profile but also a pleasant frontal appearance. The purpose of the current study was to evaluate the changes in the transverse dimensions by vertical ramus osteotomy (VRO) in the treatment of mandibular prognathism correction. Twenty patients who underwent mandibular prognathism correction by VRO were included. Lateral and frontal cephalometric radiographs were obtained at the following stages: preoperative (T1), immediately after the surgery (T2), and completion of orthodontic treatment (T3). Three linear measurements (menton, intercondylion, and intergonial distances) and the ramus angle were compared from T1 to T3. A final mean menton setback of 12.2 mm and upward movement of 0.3 mm were noted. The intercondylion and intergonial distances significantly increased by 5.1 and 7.1 mm, respectively. Without significant difference, ramus angles decreased 1.7 degrees in the right side and 0.1 degrees in the left side. The surgical correction of mandibular prognathism using VRO led to an increase in the transverse dimensions.

Assessment of the Related Factors of Blood Loss and Blood Ingredients Among Patients Under Hypotensive Anesthesia in Orthognathic Surgery

The objective of the study was to understand the factors associated with presurgical and postsurgical blood loss and blood ingredients among patients in the treatment of mandibular prognathism by intraoral vertical ramus osteotomy combined genioplasty. Preoperative and postoperative values of blood loss and blood ingredients were collected from 30 mandibular prognathic patients who underwent orthognathic surgery. The linear regression models and correlation coefficients were used to identify factors with respect to patients' blood loss level and 3 types of blood ingredients (ie, red blood cells, hemoglobin, and hematocrit). The mean blood loss and operation time were 179.2 mL and 311.7 minutes, respectively. No blood transfusion was received by our patients. After adjusting for potential factors, the regression models showed that no significant factor was found to be associated with blood loss and reduce blood ingredients. Moreover, female patients were found to be more likely to have a low level of presurgical blood ingredients (β = -0.293 to -3.551; P < 0.05), whereas female sex (β = -1.606 to -4.008; P < 0.001), a high blood loss level (β = -0.003 to -0.009; P < 0.05), and long operation time (β = -0.005 to -0.018; P < 0.05) were associated with a low level of postsurgical blood ingredients (ie, hemoglobin and hematocrit). No significant factor was associated with blood loss and reduced blood ingredients among patients in orthognathic surgery with hypotenstive anesthesia. Improvements in anesthesia provided surgeons with more time to promote hemostasis during surgery. Hypotensive anesthesia was a well-accepted method to reduce blood loss during orthognathic surgery.

Impact of Different Surgery Modalities to Correct Class III Jaw Deformities on the Pharyngeal Airway Space

The objective of the study was to compare the outcome of different modalities of orthognathic surgery to correct class III jaw deformities concerning the pharyngeal airway space, especially in patients with other predisposing factors for the development of obstructive sleep apnea. Lateral cephalograms of 30 Japanese patients (12 males and 18 females, 24.4 [SD, 6.8] years), who underwent surgical-orthodontic treatment for class III jaw deformities, were obtained. Patients were divided into 3 groups: Group A included patients who underwent bilateral sagittal split ramus osteotomy; group B patients underwent bimaxillary surgery, and group C patients underwent intraoral vertical ramus osteotomy. Lateral cephalograms were assessed before surgery and around 3 months and 1 year after surgery. The paired t-test was used to compare the groups, and P < 0.05 was considered significant. In groups A and C who underwent sagittal split ramus osteotomy and intraoral vertical ramus osteotomy, respectively, the pharyngeal airway was constricted significantly at the 3 levels of the pharyngeal airway space on short- and long-term follow-up, whereas in group B, who underwent bimaxillary surgery, no significant changes were noted on long-term follow-up. Bimaxillary surgery rather than only mandibular setback surgery is preferable to correct class III jaw deformity to prevent narrowing of the pharyngeal airway, which might be a predisposing factor in the development of obstructive sleep apnea syndrome.

Endoscopically-assisted subcondylar and vertical ramus osteotomies for the treatment of symmetrical mandibular prognathism

The author describe the endoscopically-assisted intraoral vertical ramus (IVRO) and subcondylar (ISCO) osteotomies for the treatment of symmetric mandibular prognathism. The use of the saw and the bone chisel under the continuous control of the endoscope provides a safer approach since the osteotomy is controlled during the whole process. The introduction of the endoscope to provide complete visualization of the osteotomy site may overcome the traditional limitations of direct visualization in IVRO and ISCO.

Correlation Between the Change of Gonial Region and Skeletal Relapse After Intraoral Vertical Ramus Osteotomy for Correction of Mandibular Prognathism

The gonial region is coincided with harmonious face and masticatory function. The aims of the present study were to assess changes in the gonial region in patients who had mandibular setback surgery by intraoral vertical ramus osteotomy (IVRO) and to investigate the contributing factors in relation to skeletal relapse. Twenty-one patients with mandibular prognathism were corrected by IVRO. Three cephalometric radiographs were collected from preoperative orthodontic treatment (T1), immediately after surgery (T2), and at 2-year postoperative follow-up (T3). Relapse was defined as forward movement of menton (Me) after the 2-year follow-up. Three angular (SN-Go angle, mandibular plane angle, and gonial angle) and 2 linear (horizontal-Me and vertical-Me) measurements were compared after immediate operation and at the 2-year follow-up. Spearman rank correlation and Student t tests were used for statistical analysis. The mean setback of the Me was 12.7 mm, and the mean relapse was 1.5 mm. The magnitude of setback was not significant for relapse. There were weak correlations between relapse and factors concerned with the gonial region (SN-Go angle, mandibular plane angle, and gonial angle). Surgical correction of mandibular prognathism using IVRO can lead to an increase in the angle changes of gonial region but not correlate to skeletal relapse in long-term follow-up.