The pterygomaxillary junction: An imaging study for surgical information of LeFort I osteotomy

Le fort I osteotomy with or without concomitant removal of upper third molars: A prospective cohort study of intraoperative findings, related complications, and level of pterygomaxillary separation after down-fracture

The main objective of our study was to assess the clinical implications of concomitant intraoperative removal of maxillary third molars (M3M) with the Le Fort I osteotomy 'twist' technique (LF1twist). A prospective comparative study was carried out regarding the necessity of bone trimming around the pedicle, intra- and postoperative complications, surgery time, and the level of pterygomaxillary junction (PMJ) separation following LF1twist with concomitant intraoperative removal of M3M (test group) versus LF1twist alone (control group). Outcome parameters were assessed from clinical and radiographic measurements. In total, 100 surgery sites were included (50 in each group). The mean surgery time was 53.4 ± 7.8 min, with nonsignificant differences between groups. The frequency of intraoperative complications was negligible, with no significant differences between groups - though all bleeding events (n = 4) occurred when M3M was not removed concomitantly. No postoperative complications were recorded. Percentages of disarticulations occurring at the PMJ were similar in both groups. In conclusion, the results demonstrate that removal of M3M in conjunction with LF1twist does not imply additional surgery time, or differences regarding the level of PMJ separation or perioperative complications. Furthermore, the concomitant procedure reduces the amount of maxillary and palatal bone in the disjunction area, which facilitates down-fracture and field clearing for maxillary repositioning.

Advantages of a High-Powered Ultrasonic Vibration Cutting Device for Orthognathic Surgeries

This study aimed to evaluate the advantages of using a high-powered ultrasonic vibration cutting device (HP-UVCD) in orthognathic surgeries. We analyzed 22 consecutive patients who underwent Le FortⅠosteotomy and bilateral sagittal split osteotomies for cleft lip and palate. We used conventional power instruments, such as reciprocating saws and rotating burrs in the first 10 patients, and an HP-UVCD in the remaining 12 patients. Surgical time, intraoperative blood loss, and postoperative inferior alveolar nerve affection were retrospectively investigated. The surgical time in the ultrasonic group (223±12.217 min) was significantly shorter than that in the conventional group (278±11.153 min, P =0.008). The amount of intraoperative blood loss in the ultrasonic group was an average of 230±45.154 g, and that in the conventional group was an average of 343±49.463 g. Although the blood loss in the ultrasonic group was reduced compared with that in the conventional group, this difference was not statistically significant ( P =0.118). All patients in both groups recovered normal sensation by 6 months postoperatively. Our findings suggest that the HP-UVCD can be used in place of a reciprocating saw or rotating burrs in orthognathic surgeries, resulting in reduced surgical time and minimal blood loss. The use of an ultrasonic bone-cutting device may allow for a safer and less invasive orthognathic surgery.

Single-Splint, 2-Jaw Orthognathic Surgery for Correction of Facial Asymmetry: 3-Dimensional Planning and Surgical Execution

Three-dimensional (3D) planning of orthognathic surgery (OGS) improves the treatment of facial asymmetry and malocclusion, but no consensus exists among clinicians regarding technical details. This study verified the consistency of authors' workflow and strategies between 3D planning and surgical execution for facial asymmetry. This retrospective study recruited consecutive patients (n=54) with nonsyndromic facial asymmetry associated with malocclusion. The stepwise workflow included orthodontic treatment, 3D imaging-based evaluation, planning, and transferring the virtual of single-splint 2-jaw OGS to actual surgery in all patients. Seven landmark-based measurements were selected for postoperative assessment of facial symmetry. Fifty patients had no anesthetic/surgical-related episode and procedure-related complications. Others experienced wound infection (n=1), transient TMJ discomfort (n=1), and facial numbness (n=3). Two cases had minor residual asymmetry (cheek and chin, respectively), but did not request revisionary bone or soft tissue surgery. Comparisons between the planned and postoperative 3D images with quantitative measurement revealed acceptable outcome data. The results showed a significant increase in facial symmetry at 7 landmark-based postoperative measurements for both male and female. This 3D-assisted pathway of OGS permitted achievement of consistent satisfactory results in managing facial asymmetry, with low rate of complications and secondary management.

Pattern of pterygomaxillary disarticulation associated with Le Fort I maxillary osteotomy

Pterygomaxillary disarticulation (PMD) contributes to surgical complications of Le Fort 1 osteotomy and is associated with undesirable fractures of the pterygoid plates. The aim of this paper was to investigate the patterns of PMD in Le Fort I osteotomies using Rowe's disimpaction forceps, and to evaluate correlations with age and anatomical measurements. Cone-beam computed tomography (CBCT) scans of 70 consecutive orthognathic patients were retrospectively evaluated to study four patterns of PMD: Type 1 - PMD at, or anterior to, the pterygomaxillary junction (PMJ); Type 2 - PMD posterior to the PMJ; Type 3 - PMJ separation with comminuted fracture of the pterygoid plates; Type 4 - disarticulation of the maxilla involving the pterygoid plates above the level of the osteotomy line. The preoperative anteroposterior and mediolateral thicknesses of the PMJ and the length of the medial and lateral pterygoid plates were assessed. Satisfactory PMD was achieved in all cases and no severe complications were reported, including vascular, dental, mucosal, or neural damage. The most common PMD was Type 1 (54.3%), followed by Type 2 (40%). Comminuted fracture of the pterygoid plates was limited to 5.7% of cases, and no Type 4 was detected. A weak correlation was detected between PMJ thickness and PMD pattern (p = 0.04). No statistically significant correlation was detected between patients' age and type of PMD. PMD of Le Fort I maxillary osteotomy using a Smith spreader and Rowe's disimpaction forceps proved safe, with minimal damage to the pterygoid plates.

Sinus mucosal healing pattern according to pterygomaxillary disjunction type after Le Fort I osteotomy

OBJECTIVES

During Le Fort I osteotomy, the separation of the pterygomaxillary junction (PMJ) is a difficult procedure for most surgeons because it is invisible. In this process, damage to the posterior structures constituting the sinus or those adjacent to it, including the maxillary sinus posterior wall and pterygoid plate, may occur. We would like to investigate the effects of this on the inside of the maxillary sinus after surgery and whether there are complications.

MATERIALS AND METHODS

One-hundred patients who underwent Le Fort I osteotomy from 2013 to 2020 using cone-beam computed tomography images were classified into two groups (clean-cut type and fractured type) according to the PMJ cutting pattern. In addition, the mucosal thickness in the maxillary sinus was divided into preoperative, postoperative three months, one year, and the change over the course of surgery was evaluated retrospectively.

RESULTS

Of the total 100 cases, the clean-cut type numbered 28 cases and the fractured type totaled 72 cases. Among the fracture types, part of the sinus wall and the pterygoid plate were broken in 69 cases, and the maxillary sinus posterior wall was detached in three cases. There was no statistically significant difference in sinus mucosal thickening between the clean-cut type and fractured type of the PMJ, three months and one year after surgery between the two groups. However, there was a significant difference in sinus mucosal thickness at postoperative one year in the case where a partial detachment of the maxillary sinus posterior wall occurred compared to not.

CONCLUSION

Even if there is some damage to the structures behind the PMJ, it may not be reasonable to spend some time on the PMJ separation process considering the overall postoperative complications, if there is no significant difference inside the sinus, or increased probability of postoperative complications.

Customized guide for transmucosal pterygomaxillary disjunction: Proof of concept

Potential complications related to pterygomaxillary disjunction have been widely described in the literature, most of them being due to the inaccurate and blind approach involved. The present study used preoperative virtual planning to establish a surgical cutting guide for pterygomaxillary osteotomy. It was placed in the maxillary tuberosity supported by molars, and a flapless vertical osteotomy was performed with a piezoelectric saw. Then, maxillary down-fracture was performed with slight pressure through an anterior approach. The use of the surgical guide added accuracy and predictability to the procedure, with no prolongation of the surgery time. There were no undesired fractures or bleeding. Regarding manipulation of the surgical guide in the posterior area, it was found to be easily manageable and very stable over the posterior teeth, due to its small size and precision, respectively. In conclusion, this technique seems to improve the accuracy of pterygomaxillary disjunction without prolonging the surgery time. Furthermore, it reduces potential complications related to the conventional procedure. Nevertheless, a larger body of patient data is needed to confirm the benefits of the technique.

Transmucosal pterygomaxillary disjunction using a piezoelectric device, in the context of the minimally invasive Le Fort I osteotomy protocol

The aim of this study was to assess the accuracy and clinical implications of pterygomaxillary junction (PMJ) disjunction with a transmucosal PMJ osteotomy using a piezoelectric hand-piece device, in the context of Le Fort I osteotomy, by evaluating the level of PMJ disarticulation and the need for bone trimming around the pedicle. An ambidirectional 1-month follow-up cohort study was designed involving consecutive patients undergoing minimally invasive maxillary Le Fort I osteotomy through the twist technique. Two cohorts were defined according to whether or not the transmucosal PMJ osteotomy was performed. The site of PMJ disjunction was analysed radiographically. A total of 114 patients were included in the study, 57 in each group. The overall accuracy of the PMJ disjunction path was higher in the test group (43.9%) than in the control group (15.8%). Multiple logistic regression analysis identified the need for bone trimming (odds ratio 0.02; P < 0.001) and removal of the upper third molar (odds ratio 0.17; P < 0.001) as relevant factors. In conclusion, compared with the originally described twist technique, combination of the latter with the PMJ osteotomy increased its accuracy at the level of the PMJ. As a result, there is a decrease in resistance during down-fracture and decrease in the need for bone trimming around the pedicle, with preservation of the minimally invasive concept.

A Radiographic Study on Pterygoid Implants with Hamulus as a Landmark for Engaging the Pterygoid Plate - A Retrospective Study

Introduction

Rehabilitating the posterior maxilla with pterygoid implants can be quite challenging as the area entails many hindrances for implant placement. Although few studies have reported the three-dimensional angulations according to various planes (Frankfort horizontal (FH), sagittal plane, occlusal or maxillary planes), no anatomical landmarks have been identified to guide their placement. This study aimed at analysing the three-dimensional angulation of pterygoid implants using the hamulus as an intraoral guide.

Methods

Pre-operative cone-beam computed tomography scans (axial and parasagittal sections) of 150 patients rehabilitated with pterygoid implants were retrospectively analysed to determine the horizontal and vertical angulations in relation to the hamular line and FH plane, respectively.

Results

The results showed horizontal buccal and palatal safe angulations of 20.8° ± 7.6° and -20.7° ± 8.5° in relation to the hamular line. Maximum and minimum vertical angulations of 61.6° ± 7.0° and 37.2° ± 10.3° were observed, with a mean of 49.8 ± 8.1 in relation to FH plane. The post-operative scans showed that around 98% of the implants placed along the hamular line were successfully engaging the pterygoid plate.

Discussion

Comparing with the results of previous studies, this study concludes that when implants are placed along the hamular line, they are more likely to engage the centre of the pterygomaxillary junction resulting in an excellent prognosis of pterygoid implants.

Evaluating Morphology of the Pterygomaxillary Junction and Its Association With the Orbit in Different Facial Skeletal Relationships

PURPOSE

The etiology for blindness after Le Fort I osteotomy is poorly understood. The authors propose that a study of the morphology and anatomical relationship of the pterygomaxillary junction to orbital vital structures may be crucial for understanding the possible etiology.

MATERIALS AND METHODS

This retrospective observational study involved analysis of data procured from computed tomography scans of individuals who were categorized into 4 groups based on their skeletal characteristics: skeletal Class I, II, and III and cleft lip palate (CLP). The outcome variables included i) the height, width, and thickness of the pterygomaxillary junction (PTMJ) which represent its morphology and ii) distance of the PTMJ to the superior orbital fissure and optic canal, to demonstrate its proximity to orbital vital structures. Primary outcome measures were to i) compare variance of the outcome variables across groups, ii) determine association between PTMJ morphology and its proximity to the orbit, and iii) determine association between skeletal morphology and the outcome variables. Data were analyzed using descriptive and inferential statistics to study variance and association.

RESULTS

Forty patients (80 sides) were divided into 4 groups. The CLP group demonstrated maximum height and thickness of the PTMJ, whereas the Class II group demonstrated the minimum (P < .001 and P = .001, respectively). The CLP group demonstrated the closest proximity of the PTMJ to orbital vital structures (P < .001), with Class II being the farthest (P < .001). There was a weak positive correlation between the PTMJ height and its thickness and width, whereas a moderate negative correlation was seen between the PTMJ height and its distance from the optic canal and superior orbital fissures (P < .001).

CONCLUSIONS

Morphology of the PTMJ varies with facial skeletal relationship and also influences the relationship of the PTMJ with the orbital vital structures. This may be critical in understanding the pathophysiology of blindness after Le Fort I osteotomies.

Digital Occlusion Setup Is Quantitatively Comparable With the Conventional Dental Model Approach: Characteristics and Guidelines for Orthognathic Surgery in Patients With Unilateral Cleft Lip and Palate

BACKGROUND

The evolving 3-dimensional computer-based technology revolutionized the field of orthognathic surgery (OGS). Digital occlusion setup for OGS may provide advantages in the planning comparing with the conventional approach based on the manual setup using dental casts, but we are not aware of any study focusing on digital occlusion setup for cleft OGS. The purposes of this study were to compare the conventional and digital occlusion setup approaches and to propose a protocol for digital occlusion setup in unilateral cleft OGS.

METHODS

Thirty consecutive patients with unilateral cleft lip/palate who underwent orthodontic treatment by a single orthodontist and 2-jaw OGS by a single surgeon using 3-dimensional surgical simulation were adopted for analysis. Quantitative data were collected from the dental cast occlusion setup approach (conventional group). A multidisciplinary team combined this quantitative data and established a protocol for digital occlusion setup in cleft OGS. Digital occlusions were set according to this protocol using the images of the 30 patients, and quantitative data were collected accordingly (digital group). The results of 2 groups were compared. All information was reviewed to refine the protocol and define the final guidelines.

RESULTS

There were no significant differences (all P > 0.05) for all parameters, except midline discrepancy (conventional group > digital group, P < 0.001). The root-mean-square deviation (0.46 ± 0.26 mm) indicated acceptable relationship between the conventional and digital groups. A 6-step protocol for digital occlusion setup in cleft OGS was established: dental midline, overjet/overbite, yaw rotation, pitch rotation, roll rotation, and overall facial skeletal appearance.

CONCLUSIONS

This study shows that digital occlusion setup is quantitatively comparable with the conventional dental model approach and contributes for cleft OGS by establishing a protocol for surgical occlusion setup using digital approach.

Postoperative CT findings of orthognathic surgery and its complications: A guide for radiologists

Orthognathic surgery is the standard procedure to correct congenital, developmental, or acquired dentofacial deformities. The maxillomandibular relationship corrected by orthognathic surgery can improve facial esthetics, masticatory function, articulation, and breathing. The most common types of osteotomies include the combination of Le Fort I osteotomy, bilateral sagittal split mandibular ramus osteotomy, and genioplasty. High-resolution low-dose computed tomography is useful for evaluating the facial skeleton and soft tissues after surgery as well as for depicting a variety of possible complications. This article reviews the postoperative imaging findings of the most common orthognathic surgeries and their potential complications on multidetector-row computed tomography.

Characteristics of the Sphenoid Bone in Crouzon Syndrome

BACKGROUND

The goal of this study is to analyze the safety of reconstructive surgeries for Crouzon syndrome, and to understand the deformities and complications related to the surgical procedure.

METHODS

Thirty-nine subjects underwent preoperative computed tomographic scans were included (Crouzon, n = 19; controls, n = 20) in this study. Craniofacial cephalometric measurements were analyzed by Materialise software.

RESULTS

The overall average distance from the pterygoid junction to the coronal plane in the patients with Crouzon syndrome was 21.34 mm (standard deviation [SD] 5.13), which was deeper than that in the controls by 35% (P = 0.000).The overall average distances between the left and right foramen ovale and pterion on the sphenoid bone in the subjects were 64.93 mm (SD 7.56) and 67.83 mm (SD 8.57), which were increased by 13% (P = 0.001) and 14% (P = 0.001) compared with those in the controls.The overall distances between the most inferior point of the left and right lateral pterygoid plate and the medial pterygoid plate in the subjects were 51.09 mm (SD 6.68) and 51.51 mm (SD 10.98), which was not statically different from the controls (P = 0.887, P = 0.991, respectively).

CONCLUSIONS

This study characterized the surgically relevant anatomy of the sphenoidal bone. The pterygomaxillary junction is located in the posterior of the skull. Though there are some anatomical differences due to age, it is well known that the cranial cavity of the sphenoid side is likely to be enlarged in Crouzon syndrome, which may contribute to the other complications of the disease.

Evaluation of Lefort I Osteotomy Line and Pterygomaxillary Junction Region in Patients With Cleft Lip and Palate

OBJECTIVE

This study aimed to evaluate the Le Fort I osteotomy line and pterygomaxillary junction via cone-beam computed tomography in individuals with cleft lip and palate (CLP).

DESIGN

Retrospective study. Patients and Methods: The study included individuals older than 16 years with CLP, who were scheduled for repositioning of the maxilla by Le Fort I osteotomy, and those with class III malocclusion with maxillary hypoplasia, who were scheduled for Le Fort I osteotomy. The measurements made in the area of the cleft of individuals with CLP were compared with both the side with no cleft and those with class III malocclusion with maxillary hypoplasia. A total of 11 measurements were made on the axial section parallel to the Frankfurt Horizontal plane, corresponding to the lower 1/5 of the distance between the infraorbital foramen and the anterior nasal spine.

RESULTS

There were significant differences both in the comparisons made between the individuals with CLP and those without CLP in terms of the canal-anterior alveolar crest (G) and sinus-anterior alveolar crest (L) measurements (P < .05). The mean measurement values showed that the measurement results were higher in individuals with CLP in general.

CONCLUSION

In conclusion, we believe that there might be difficulties both in osteotomy and down fracture stages during Le Fort I osteotomies performed in individuals with CLP.

CBCT study on the positional relationship between marginal points of pterygomaxillary junction and anterior nasal spine

PURPOSE

This study aimed to locate the inferior end (Pti) and the superior end (Pts) of pterygomaxillary junction (PMJ) relative to anterior nasal spine (ANS) so as to provide references for pterygomaxillary separation.

METHODS

The study was based on CBCT images of 109 Chinese patients. We projected Pti and Pts to the frontal plane and measured the distance as well as the positional relationship between the projection points and ANS via three-dimensional reconstruction image.

RESULTS

On average, the ANS was 5.18 mm above the Pti and the horizontal distance between the Pti and ANS was 21.86 mm. The horizontal and vertical distances between Pts and ANS was 20.41 mm and 10.91 mm, respectively. The vertical height of PMJ was 16.09 mm. Scatter plots diagrammatic centered on ANS showed that 73% (160/218) Pti and 64% (140/218) Pts appeared in a 45° fan shape ranged from 20 to 25 mm radius in bilateral inferior and superior quadrant, respectively. There was no significant difference in the distance between both sides (P > 0.05).

CONCLUSION

During the pterygomaxillary disjunction, it exists a risk of injuring neurovascular bundle of the pterygopalatine fossa 16.09 mm above the lowest border of the pterygomaxillary junction. The region within a 45° fan shape ranged in 20-25 mm radius in inferior quadrant centered on ANS might be suitable for the osteotome position. The positional relationship especially between the ANS and Pti found in this study provides a reference for surgeons during pterygomaxillary disjunction.

Evaluation of the Pterygomaxillary Separation Pattern in Le Fort I Osteotomy Using Different Cutting Instruments

PURPOSE

Pterygomaxillary separation (PMS) is considered the main reason for serious complications associated with Le Fort I osteotomy. The aim of this study was to evaluate whether a piezo surgery, ultrasonic bone scalpel, or conventional bur used in Le Fort I osteotomy has an influence on PMS patterns.

MATERIALS AND METHODS

Using a retrospective cohort study design, we enrolled a sample composed of patients who underwent orthognathic surgery. The primary predictor variables were the cutting instruments (ultrasonic bone scalpel, piezo surgery, and Lindeman bur) used to perform Le Fort I osteotomy. Other variables were demographic and anatomic parameters. The outcome variable was the type of PMS pattern, classified as follows: type 1, PMS at the pterygomaxillary junction (ideal PMS); type 2, PMS at the greater palatine foramen; type 3, PMS from the posterior wall of the maxillary sinus; and type 4, PMS with lateral or medial pterygoid fracture. Anatomic parameters, that is, the thickness and width of the pterygomaxillary junction and distance of the greater palatine foramen, were measured on preoperative cone-beam computed tomography images. The pattern of PMS was evaluated on postoperative cone-beam computed tomography. Data were analyzed using analysis of variance and the Pearson χ² test. P < .05 was considered statistically significant.

RESULTS

This study sample was composed of 96 PMSs in 48 patients. The most common type of PMS was type 1 (58), followed by type 4 (21), type 2 (10), and type 3 (7). A statistically significant relation was found between the cutting instrument and the ideal separation (type 1 PMS) pattern (P = .032), and the highest rate of the ideal separation pattern was seen in the ultrasonic bone scalpel group, at 24 of 32, compared with 22 of 38 in the piezo surgery group and 12 of 26 in the conventional bur group.

CONCLUSIONS

According to the study, the ultrasonic bone scalpel is safer than other cutting instruments in terms of the ideal separation of the pterygomaxillary junction.

Changes of Stress Distributions Around Pterygomaxillary Junction With Different Osteotome Angulations

The aim of this study was to investigate how the alteration of the angulation of osteotome at pterygomaxillary junction affects lateral pterygoid plate, maxillary tuberosity, palatal surface of maxilla, palatine bone and body of sphenoid bone. Following reconstruction of 3D modelling of maxilla, Osteotomes' tip was angulated 45 and 90 to sagittal plane to simulate pterygomaxillary osteotomy. Finite element analyses (FEA) was performed and Von Misses stress distributions were analyzed for two different angulations. Independent sample t test was used to compare differences between 45 and 90 angulations. Von Misses stress values on lateral pterygoid plate were higher in 45 angulation (0.71 ± 0.21 MPa) than 90 angulation (0.54 ± 0.28 MPa). This difference was statistically significant (P < 0.01). Placement of osteotome's tip with 90 angulation had higher stress value than 45 angulation on maxillary tuberosity region. However; difference wasn't significant (P = 0.44). Stress values on body of sphenoid bone were 0.45 ± 0.17MPa for the case of 90 angulation and 0.19 ± 0.09MPa for 45 angulation. Difference between these values were statistically significant (P < 0.01). Possible risk of unfavourable lateral pterygoid plate fracture and complications related with body of sphenoid bone during pterygomaxillary osteotomy was remarkably increased in case of narrow angulation (45). Keeping osteotome at right angle with sagittal plane may avoid these complications.

Relationship between pterygomaxillary fissure morphology and maxillary/mandibular position : A cone beam computed tomography assessment

PURPOSE

The aim of this study was to investigate the possible correlation between maxillary and mandibular positioning via cephalometric analysis with pterygomaxillary fissure (PMF) morphology using cone beam computed tomography (CBCT).

METHODS

In this study, CBCT images from 825 individuals (448 female, 377 male; age range was 18-91 years with this cohort) were analyzed; PMF length and width were measured. Three-dimensional cephalometric analysis was also performed using cephalometric analysis software. The landmarks and measurements in relation to maxillary and mandibular positions were identified and performed for the cephalometric analysis. Analysis of variance (ANOVA) was used for comparison of the parameters, while the Bonferroni test was used for multiple comparisons. Pearson's test was also used to assess the correlations between the parameters.

RESULTS

The results showed that males had significantly larger PMF length (p < 0.001) and width (p < 0.001) compared to females. The mean PMF length was 17.7 mm (standard deviation [SD] 3.2 mm) for right and 17.7 mm (SD 3.3 mm) for left but were not significantly different (p > 0.05). In terms of the cephalometric measurements, a significant correlation was found between upper central incisor (U1toAperp2D) and posterior facial height (PostFaceHtSGo2D) and PMF length, while correlations were found between PMF width and several cephalometric parameters such as lower lip (LwLiptoEPln2D and LwLiptoHLine2D) and occlusal plane (OPtoFHAng2D) (p < 0.05).

CONCLUSION

A significant relationship was observed between PMF morphology and the position of the maxilla or mandible. PMF lengths and widths were larger in males than females. Posteroanterior maxillary and mandibular lengths and posterior facial height are associated with PMF length and width.

Three-dimensional descriptive study of the pterygomaxillary region related to pterygoid implants: A retrospective study

The objective of this study was to analyze three-dimensionally the morphological characteristics of the pterygomaxillary region related to pterygoid implants. Volume, height, width and bone density were studied in relation to age, sex and dental status. This retrospective observational study analyzed the CBCT of 52 hemi-maxillas three-dimensionally (females n = 28, males n = 24; dentate = 31, edentulous = 21). Patients were exposed between September 2009 and October 2014, and data collection was performed between November 2015 and May 2016. Bone density, volume, height and width were analyzed in various locations of the maxilla and pterygoid process, and the variables age, gender and dental status patients were compared. The results show that the mean width of the pterygomaxillary joint was 7.5 mm (SD 1.00 mm), mean height was 12.51 mm (SD 1,82 mm) and mean volume was 321.7 mm³ (SD 142.02 mm³). Statistically significant differences between dentate and edentulous patients were found, showing a higher osseous density in dentate patients in the pterygoid process (758.2, SD 106.8, 95% CI 729.2 to 787.3 GSD - Gray Scale Density - compared to 689.9, SD 107.3, 95% CI 660.8 to 719.1 GSD; P = 0.022). In the maxilla, density was statistically significant lower in female subjects (571.0, SD 74.1, 95% CI 594.9 to 645.4 GSD) than in male subjects (620.2, SD 93.8, 95% CI 594.4 to 645.4 GSD, P = 0.047). In conclusion, due to the significant variation in the morphological characteristics of the pterygomaxillary region among subjects, personalized pre-surgical radiological assessment should always be performed. Gender, age and dental status are critical factors as they significantly affect bone density in this region.

The outcome of skeletofacial reconstruction with mandibular rotation for management of asymmetric skeletal class III deformity: A three-dimensional computer-assisted investigation

The mandibular proximal ramus segments should be moved and rotated during orthognathic surgery-based skeletofacial reconstruction for the correction of challenging patients with facial asymmetry and malocclusion, but quantitative data regarding this rotation were not sufficient to date. This 3D computer-assisted study measured the proximal ramus segment rotation after 3D simulation-guided two-jaw surgery in patients with facial asymmetric deformity and class III malocclusion (n = 31). Using 3D mandible models and a reliable proximal ramus segment-related plane, angular changes in pitch, roll and yaw directions were measured before and one month after surgery. Significant rotational changes (p < 0.01) were observed in the left and right sides and overall proximal ramus segments after surgery, with absolute differences of 4.1 ± 3.0 (range −7.8 to 6.9), 2.8 ± 2.3 (−8.8 to 5.0), and 2.7 ± 2.4 (−6.6 to 9.9) degrees in pitch, roll, and yaw rotations, respectively. Numbness and mouth opening limiting occurred within the first 6 months after surgery but the patients had an unremarkable long-term postoperative course, with no revisionary surgery required. This study contributes to the multidisciplinary-related literature by revealing that proximal ramus segment rotation and rigid fixation with no postoperative intermaxillary immobilization was practicable in skeletofacial surgery for the successful treatment of asymmetric deformity and class III malocclusion.

Update on complications in cleft orthognathic surgery

PURPOSE OF REVIEW

To give an update on recent publications and tendencies concerning complications in cleft orthognathic surgery.

RECENT FINDINGS

Cleft-specific changes after orthognathic surgery and their impact on surgical outcomes are discussed. Focus lays on the causes and mechanisms of cleft-related surgical complications and strategies to prevent or minimize these complications. Bimaxillary surgery is seen as a safe procedure for cleft patients. Maxillary distraction, total or segmental, is pointed out as an alternative method to improve outcomes. Different techniques for osteotomies and maxillary mobilization could decrease adverse events.

SUMMARY

Cleft patients are more susceptible to the occurrence of complications because of peculiar presurgical conditions. Different surgical approaches and techniques are presented to overcome these difficulties, to achieve better results and to increase patient safety. The importance of communication between patient, family and cleft team members is emphasized.