Cortex-to-cortex healing after mandibular osteotomy

Ankylosis management with autogenous grafts: A systematic review

A systematic review was performed to assess the clinical outcomes of the reconstructive methods using autogenous grafts for the management of temporomandibular joint (TMJ) ankylosis A comprehensive electronic and manual search of the literature without date or language restriction was performed in January 2021 to identify randomized controlled trials, prospective, and retrospective studies with the aim of comparing the various surgical modalities for TMJ ankylosis. Twenty-six publications were included: prospective (n ​= ​17), retrospective (n ​= ​7), randomised control trial (n ​= ​1) and ambispective study (n ​= ​1). Costochondral graft was the most common graft used followed by Coronoid process graft. Meta-analysis was not possible as most of studies were non-controlled in nature. Based on the available data, there was a strong evidence that autogenous grafts especially Costochondral grafts and coronoid grafts have remained one of the most favoured methods of reconstruction. Prospective and randomized control studies are recommended for the best stratification for the use of autogenous grafts for the management of TMJ ankylosis.

Strategies to reduce re-ankylosis in temporomandibular joint ankylosis patients

The purpose of the study was to define a protocol for the prevention of re-ankylosis after surgical management of temporomandibular joint ankylosis (TMJA). The investigators designed a retrospective study on all TMJA patients treated with different treatment modalities from 2013 to 2019. The investigators observed that complete removal of the ankylotic mass particularly on the medial side; use of a piezoelectric scalpel for a clean and smooth osteotomy with copious irrigation to remove bone chips and slurry; less trauma to the local tissue; osteotomy design parallel and inferior osteotomy at the narrowest part, which mostly corresponds to the condylar neck; performance of a coronoidectomy (if mouth opening is <30mm), fat interposition; no intraoperative correction of any pre-existing chin deviation when treated with costochondral graft; patient motivation; and aggressive physiotherapy, and use of a vacuum drain are all important to prevent re-ankylosis, irrespective of the treatment modality. A total of 114 patients (n=152 joints), [bilateral (n=38), unilateral (n=76)] were evaluated retrospectively. Interpositional arthroplasty with fat was performed in n=43, CCG was used for reconstruction in n=30 and total joint replacement (TJR) was done in n=41 patients. Re-ankylosis was seen in n=3 (2.6%) patients (2 in CCG and 1 patient in interpositional arthroplasty). The follow-up ranged from 12-80 months. The results conclude that following the suggested best practice protocol is effective in reducing re-ankylosis.

Costochondral Graft Versus Total Alloplastic Joint for Temporomandibular Joint Reconstruction

Presently, there are 2 options for the replacement of the temporomandibular joint for end-stage pathology: autogenous bone grafting or alloplastic joint replacement. This article presents evidence-based advantages and disadvantages for each of these management options to assist both surgeons and their patients in making that choice.

Is There a Difference in Stability After Intraoral Vertical Ramus Osteotomy Between Vertically High-Angle and Normal-Angle Patients?

PURPOSE

Few studies have evaluated the relapse pattern of intraoral vertical ramus osteotomy (IVRO) for the correction of mandibular prognathism with a high angle. The aim of this study was to measure the association between vertical facial types (high and normal mandibular plane angle) and relapse after IVRO for the management of mandibular prognathism.

MATERIALS AND METHODS

The retrospective cohort study sample (skeletal Class III patients) was divided into 2 groups according to the angle of the sella-nasion plane relative to the mandibular plane (SN-MP) at the initial examination. Lateral cephalograms were analyzed for the predictor (facial type) and outcome (cephalometric changes over time) variables before surgery, 7 days after surgery, and 12 months after surgery. The 2 groups were matched for sample size (n = 20 in each). Data were analyzed using repeated-measures analysis of variance with Bonferroni correction.

RESULTS

The normal-angle group (group N, SN-MP from 27° to 37°) and high-angle group (group H, SN-MP >37°) were not significantly different in terms of gender and age at the initial examination. Seven days after surgery, the mandibles in group H moved 2.5 mm more superiorly than those in group N (P = .013); consequently, the amount of overbite correction in group H was approximately 2 mm greater than that in group N (P = .002). Nevertheless, 12 months after surgery, there was no statistically significant difference in relapse of the maxilla and mandible between the 2 groups. In the 2 groups, the mandible moved approximately 0.7 mm superiorly during retention.

CONCLUSIONS

These findings suggest that IVRO is a clinically acceptable and stable treatment modality for mandibular prognathism with a high angle.

Changes in the transverse dimensions by vertical ramus osteotomy after mandibular prognathism correction

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

The surgical correction of mandibular prognathism using VRO led to an increase in the transverse dimensions.

Morphometric and morphological changes in the temporomandibular joint after orthognathic surgery: a magnetic resonance imaging and computed tomography prospective study

The possible morphological and morphometric changes in the different components of the temporomandibular joint (TMJ) after orthognathic surgery were analysed using computed tomography (CT) transverse scans and sagittal and coronal magnetic resonance imaging (MRI) images. Twenty-four patients with class III dentofacial deformity were studied. Nine had isolated maxillary osteotomies and 15 had combined maxillary and mandibular subcondylar osteotomies (MSO). Ten patients were studied as a control group. The patients were studied clinically, radiographically and with CT and MRI in four different phases in order to locate the position of the mandibular condyle in relation to the glenoid fossa. No statistically significant differences were found in the group of patients who had had isolated maxillary osteotomies throughout the four phases of the study. Patients treated by bimaxillary surgery showed different condylar movements after surgery. Intra-articular effusion was evident during the early postoperative period in patients treated by bimaxillary surgery. Although different changes in the position of the bony components of the TMJ occurred after MSO, these seemed to be transient, with no major alterations in the final outcome in the patients.

Stability of sagittal split osteotomies. A comparison of three stabilization techniques

The objective of this study was to retrospectively evaluate stability of mandibular advancement after bilateral sagittal split osteotomies were performed. Three different fixation and immobilization protocols were examined. Thirty-three patients were evaluated with preoperative, immediate postoperative, and long-term (mean, 13 months) lateral cephalometric radiographs. The patients were divided into three groups: group 1 (n = 10) had nonrigid internal fixation and 6 weeks of maxillomandibular fixation, group 2 (n = 12) had rigid internal fixation and immediate postoperative function, and group 3 (n = 11) had rigid internal fixation with maxillomandibular fixation for a mean of 14 days. Group 3 had the least amount of sagittal and vertical relapse. Differences in sagittal relapse were statistically significant between groups 1 and 3. Group 2 demonstrated greater sagittal relapse than did group 3, although the result was not statistically significant. This study suggests that the use of rigid internal fixation with a period of maxillomandibular fixation appears to be more stable than nonrigid internal fixation with maxillomandibular fixation or rigid internal fixation without maxillomandibular fixation.

Osseous healing of the sagittal ramus osteotomy: a histologic comparison of rigid and nonrigid fixation in Macaca mulatta

Twenty-three adult female rhesus monkeys underwent advancement of the mandible by the sagittal split ramus osteotomy. Twelve had the proximal and distal segments wired together and underwent 6 weeks of maxillomandibular fixation (MMF). Eleven animals had bicortical bone screws placed between the segments and no postsurgical MMF. The animals were killed at 6 and 12 weeks and the osteotomy sites were prepared for histologic examination. Overall, the results showed that the two groups of animals underwent markedly different patterns of osseous healing. The osteotomy sites in the MMF animals were filled with callus, which then formed bone. In contrast, no callus was found in the majority of the rigid fixation osteotomy sites; direct bony deposition was found instead. The results of this investigation show that, like long bones, the sagittal osteotomy can heal by direct or indirect means depending on the rigidity of the fixation.

Slot osteosynthesis technique (SLOT) for sagittal ramus split osteotomies. A method to optimize occlusal control and condylar seating

In the technique presented, a specially designed drill and bone holding forceps are used. These enable a horizontal slit to be cut in the condyle-bearing segment, at the site of the largest contact surface. One lag-screw is tightened in the centre of the slit at each side. By releasing the IMF (intermaxillary fixation) and untightening one or both screws, the condylar segments can be repositioned and the occlusion corrected before inserting the other tandem screws.

Masseter muscle adaptation following surgical correction of vertical maxillary excess

This study was designed to examine the adaptive response of the human masseter muscle following surgical correction of abnormal facial form. Biopsies of the deep surface of the anterior superficial masseter muscle were obtained from five patients demonstrating vertical maxillary excess (VME), one at the time of corrective surgery, and a second at a long-term postoperative time interval (mean, 8 months). Control biopsies were also obtained from five individuals (three cadavers and two patients) with normal dentofacial morphology. A standard regimen of histologic and histochemical staining was used to classify individual muscle fibers as either type 1, type 2, or intermediate. In both VME patients and normal subjects type 1 fibers predominated, with the control group displaying a higher percentage (50% vs. 43%). On the average, type 1 fibers also had the largest areas. Following surgery there was an increase in type 2 fibers (30% vs. 52%). Two patients receiving maxillary surgery only exhibited either no change in mean fiber area or only a slight increase. The three remaining patients who underwent concomitant maxillary and mandibular surgery all showed a significant decrease in mean fiber area. Two persons in the latter group also showed features consistent with a denervation-reinnervation process. The results of this study indicate that the human masseter responds to surgical manipulation of the jaws in a histochemically demonstrable manner, with the nature and magnitude of the response associated with the particular surgical procedure(s) performed.

Osteotomy length and postoperative stability in vertical subcondylar ramus osteotomy

The osteotomy sites in 80 patients treated for mandibular prognathism by intraoral (IVSO) or extraoral (EVSO) vertical subcondylar ramus osteotomy and their relationships to post-operative mandibular stability were studied. A model study demonstrated that metric orthopantomographic measurements of the ramus showed insignificant variability of magnification and distortion. The relative osteotomy length and the bony overlapping area of the osteotomized fragments were evaluated on 6-week postoperative orthopantomograms. High correlation was found between the clinical estimate of osteotomy length and metric registrations. Bony overlapping area of the IVSO and the EVSO group did not reveal differences. The mandibular positional changes during the fixation/postfixation periods were analyzed on 6-week and 6-month postoperative lateral cephalograms. Significant correlations could not be demonstrated between postoperative stability and osteotomy length or overlapping bony area. Thus the osteotomy length appears to be factor of minor importance for postoperative stability.

Stability after vertical subcondylar ramus osteotomy for correction of mandibular prognathism

A cephalometric analysis of the positional changes of the mandible and the upper and lower incisors following vertical subcondylar ramus osteotomy was performed on 80 patients. The patients were prognathic without laterognathism or open bite and all the patients had preoperative orthodontic treatment. 40 patients were operated with an intraoral (IVSO) and 40 with an extraoral approach (EVSO). Both groups showed postoperatively posterior rotation of the mandible, shortening of the posterior facial height, increase in anterior facial height and extrusion of the incisors in both jaws. A significantly greater reduction of posterior facial height was observed in the EVSO-group, but otherwise the 2 groups did not reveal any statistically significant positional differences. The material was sub-divided into 2 groups 1 with (n = 32) and one group without (n = 48) extra skeletal (nasomandibular) fixation in addition to the intermaxillary fixation. Significantly less positional changes of the incisors and less increase of anterior facial height was found in the group with skeletal fixation, but the influence on other skeletal alterations was limited. After release of the intermaxillary fixation, the only difference between the groups was intrusion of the earlier extruded incisors, most pronounced in the group without skeletal fixation.

The surgical technique of vertical subcondylar osteotomy for correction of mandibular prognathism. A 10-year survey

In the period 1975-1985 extraoral vertical, subcondylar osteotomies of the mandibular ramus (EVSO) were performed in 203 patients with mandibular prognathism at Haukeland University Hospital, Bergen. Refinements of this surgical technique are described. Clinical and surgical observations were analyzed as to preoperative orthodontic treatment, operation time, pre-/post-operative complications, and hospital stay. The findings confirm that the EVSO procedure is a safe technique, with minimal discomfort and morbidity for the patients. Even though intraoral procedures are the trend for surgical correction of mandibular prognathism at present, there are substantial indications for the use of EVSO.

Geographical distribution, preoperative orthodontics, and morbidity of Norwegian patients surgically treated for mandibular prognathism

The geographical distribution of 1169 Norwegian patients operated on for mandibular prognathism during the years 1975-1984 showed an accumulation of cases in the western and northern parts of the country. This skew distribution was probably due to genetic factors. No association was found between the number of operated patients and the number of orthodontists or oral and maxillofacial surgeons in the different counties. Most of the patients (69%) had less than 2 years and 10% had more than 4 years of preoperative orthodontic treatment. The use of presurgical orthodontics seemed to increase during the observation period, and the mean treatment time was shorter in the last half of the decade. The morbidity, defined as the duration of the hospital stay and the intermaxillary fixation period, was on an average 56 days, mostly dependent on the surgical unit.

Intraoral vertical subcondylar osteotomy: a national survey

The results of a national survey pertaining to the IVSO are presented and the findings are contrasted with the literature on the procedure. It was found that the IVSO is a popular procedure for mandibular setback, that the value of determining the mandibular divergence angle is equivocal, that the Stryker oscillating saw is the most popular instrument for performing the osteotomy, that most operators leave the segments unfixed, and that the intraoral approach to the correction of mandibular prognathism is preferred. There were no geographic trends noted.

Stability associated with mandibular advancement treated by rigid osseous fixation

Relapse after a mandibular sagittal ramus split osteotomy (SSO) fixed by transosseous wire has been shown to occur. Authors who use rigid screw fixation claim a lesser incidence of such relapse. Nine subjects with horizontal mandibular deficiency treated by an SSO and fixed with bone screws were prospectively studied. Serial cephalometric radiographs were traced and superimposed on the sella-nasion line and anterior cranial base structures. A markedly reduced horizontal movement during the first six weeks at both points B and Pg, followed by a slight advancement at six months, was observed. Concomitantly, the surgically increased facial height was shown to subsequently decrease during both those time intervals. The stability of this procedure warrants further investigation.