Maurice Y. Mommaerts

No evidence for long-term effectiveness of early osteodistraction in hemifacial microsomia.

Background: The authors performed a critical literature review to find evidence of the long-term stability after early distraction osteogenesis of the mandible in patients with hemifacial microsomia. Methods: The PubMed, Cochrane, MEDLINE, EMBASE, CENTRAL, and CINAHL databases were searched systematically for studies performed between 2002 and 2008. Abstracts from the 89 relevant articles were reviewed for evidence. Results: Thirteen articles met the inclusion criteria. Data were tabulated with respect to the length of follow-up, number of patients, age group, Pruzansky-Kaban classification of the patients, methods of analysis and validation, and level of evidence. Methods for long-term follow-up studies were not standardized, and no objective studies have been published on stability after growth cessation. Conclusions: Thus far, no randomized controlled trials on early distraction osteogenesis in hemifacial microsomia patients have been published. The authors conclude that there is a lack of statistical evidence to support the use of early distraction osteogenesis for correcting hemifacial microsomia as a single treatment modality. The results call into question its rationale.

Reconstruction of the severely resorbed maxilla with a combination of sinus augmentation, onlay bone grafting, and implants

PURPOSE A new method of reconstruction of the atrophic maxilla by combining a bilateral sinus floor elevation and cancellous bone graft with buccal and labial onlay graft using L-shaped corticocancellous blocks from the posterior iliac crest is presented. PATIENTS AND METHODS Seventeen patients were treated with this procedure. One hundred one IMZ implants were placed in 14 patients, and 22 Brånemark implants were placed in three patients. Patients were observed for 6 months after prosthetic rehabilitation. RESULTS All patients were fully rehabilitated with fixed bridges except one, who preferred an overdenture. Only two implants were lost at the time of the abutment connection. Some bone resorption was seen around six implants. The success rate with this procedure was 92.7% 6 months after prosthetic rehabilitation if implants with bone resorption were considered failures. CONCLUSIONS These preliminary results indicate that this surgical procedure is suitable for reconstruction of most atrophic maxillas.

A systematic review of the effects of bone-borne surgical assisted rapid maxillary expansion.

INTRODUCTION A systematic literature review was conducted to find out if bone-borne maxillary expansion with corticotomies is an effective and secure orthodontic/orthopaedic treatment modality, eliminating orthodontic and periodontal side effects of tooth-borne maxillary expansion with corticotomies. MATERIAL AND METHODS Randomized controlled trials (RCT), controlled clinical trials (CCT) and case series with a sample size >or=5 were electronically searched in PubMED, MEDLINE, EMBASE Excerpta Medica, CINAHL, Biological Abstracts and CENTRAL till June 2008. Data were extracted by 2 observers. RESULTS Ten studies fulfilled the inclusion criteria, of which 9 were prospective and 1 was a retrospective case series. CONCLUSION No RCTs or CCTs were published on bone-borne surgically assisted rapid maxillary expansion (SARME). For expected advantages compared to tooth-borne SARME, only weak evidence was found for less buccal tipping of the teeth used as anchor teeth in tooth-borne expansion. The heterogeneity of the retrieved publications and the wide variety of outcome variables posed serious restrictions on the review of the literature in a quantitative systematic manner. There is a need for well designed clinical trials research on the effects of tooth-borne and bone-borne SARME.

Temporomandibular joint symptoms in an orthognathic surgery population

The records of 317 consecutive patients who underwent orthognathic surgery in the Division of Maxillo-Facial Surgery of the General Hospital St. John, Bruges, Belgium, between 1.10.90 and 1.10.92 were evaluated for pre- and postoperative temporomandibular joint (TMJ) symptoms. Only 143 patients, with a normal/low angle mandibular deficiency deformity, treated by mandibular advancement, and 53 high angle absolute mandibular retrognathism patients having bimaxillary operations, were selected. Fewer TMJ symptoms were found postoperatively, than preoperatively in the total group (17.8% vs 26.5% p = 0.025, Mc Nemar). In the normal/low angle group, there was a decrease in TMJ symptoms after surgery from 30.0% to 14.6% (p = 0.0001, Mc Nemar). In the high angle group, however, more TMJ symptoms are seen postoperatively 26.4% versus 16.8% (p = 0.228, Mc Nemar). Possible hypothetical explanations are given.

Nasal profile changes after maxillary impaction and advancement surgery

PURPOSE The profile changes in the nasal tip and columello-labial region that occur after maxillary advancement and impaction surgery were measured to test the hypothesis that a subspinal osteotomy would induce less nasal tip change and would result in a more acute columello-labial angle than a conventional Le Fort I-type osteotomy. PATIENTS AND METHODS The lateral cephalograms of 2 matched groups of 23 advancement/impaction cases with and without subspinal osteotomy were analyzed electronically. RESULTS There was no difference in nasal tip elevation and change in nasal tip projection between the 2 groups. The columello-labial angle was, on average, unchanged by the surgery. A linear correlation with a weak clinical relevance could be demonstrated between nasal tip projection and maxillary advancement in the group that was treated without subspinal osteotomy. Such a correlation was not detected for nasal tip elevation in either of the groups. Palatal plane rotation had a significant influence on nasal tip projection but not on tip elevation in both groups. The correlation was strongest in the group treated conventionally. The multiple regression equation with maxillary advancement and rotation as predictors had a r2 of .6071 (nasal tip projection = 0.9 + 0.19 maxillary advancement + 0.18 palatal plane inclination) in this group. CONCLUSION The results indicate that the advancing piriform aperture pushing on the alae, and not the nasal spine, is responsible for the increase in nasal tip projection. The subspinal osteotomy is not superior to the conventional Le Fort I-type osteotomy in regard to minimizing nasal tip changes and obtaining control over the columello-labial angle.

The 'sandwich' zygomatic osteotomy: technique, indications and clinical results.

The classical approach to lateral midface hypoplasia is reconstruction with onlays. Dislocation and asymmetry, early and late infection, and extrusion are possible complications with alloplastic implant materials. Unpredictable resorption, irregular contours and asymmetry are problems that can arise with autogenous, homogenous and hetergenous onlay grafts. We describe a technique by which the zygomatic body is luxated laterally and ventrally after a combined oblique-horizontal and vertical osteotomy. The resultant greenstick fracture at the temporo-zygomatic suture together with minimal lateral degloving causes the malar body to return to its former position. An interpositional porous hydroxyapatite block acts as a space maintainer until the osteotomy sites are ossified. The restoration of contour is performed by the zygomatic body itself, not by the implants. The indications are discussed and the results of three year follow-up are illustrated.

Morbidity related to transmandibular distraction osteogenesis for patients with developmental deformities

INTRODUCTION The aim of this retrospective observational case series study was to determine the morbidity of transmandibular Distraction Osteogenesis (DO) using a bone-borne distraction device to adapt the surgical protocol and improve hardware design. PATIENTS AND METHODS The treatment of 23 consecutive, non-syndromic patients who underwent transverse mandibular DO after a midline symphyseal osteotomy with the TransMandibular Distractor (TMD ) was evaluated. The follow-up period lasted at least 1 year after the end of the contention period. Treatments were analysed according to the morphological and functional Success Criteria (SC) for Craniofacial Distraction Osteogenesis (CFDO) for patients with developmental dentofacial malformations established by the steering group of European Collaboration on Cranial Facial Anomalies (EUROCRAN). RESULTS Appropriate distraction was obtained in 22 of the 23 patients. One patient had irreversible dentition damage, consisting of an inadvertent apical section. All other SC for CFDO were fulfilled 100% at 1 year follow-up. Seven patients suffered from short-term local infections during different phases of treatment. Two patients suffered subluxation of a central incisor that healed uneventfully. Local discomfort due to delayed union (in three patients) and trauma to the lower lip (one patient) were also observed. CONCLUSION The main problems were high local infection rates and damage to an apex that required a root filling, as well as patient discomfort due to delayed union and/or the bulkiness of the TMD device. Based on the results of this morbidity study, modifications are recommended for both the surgical protocol and the TMD device hardware.

Creating lip seal by maxillo-facial osteotomies. A retrospective cephalometric study

Lateral head films taken immediately pre-operatively and at least 6 months postoperatively were analysed in 99 selected orthognathic surgery patients to study soft and hard tissue ratios in relation to lip seal creation. The patients were grouped according to the osseous correction carried out. In maxillary advancement patients, the overall position of stomion superius was difficult to predict when important horizontal and vertical movements had been made. The vertical movement of stomion superius was 30% of that seen at the anterior palate point, and 25% of that at the upper incisal point, when the main vector of maxillary repositioning was vertical (either intrusion or extrusion). There was a weak linear correlation between mandibular advancement at pogonion and vertical changes at stomion inferius. The correlation increased if vertical movement at menton and mentolabial angle were added as independent variables. Good linear correlations between vertical changes at stomion inferius and vertical changes at lower incisal point and menton were observed in mandibular set-back surgery. In mandibular autorotation, the best linear correlation with single predictors was found between vertical changes at stomion inferius and those at menton (about 80% + 1 mm upward movement), and vertical changes at stomion inferius and horizontal changes at lower incisal point. Vertical changes at stomion inferius were mainly determined by vertical changes at menton in genioplasties, the change at stomion inferius being 40% of that at menton. The horizontal component at pogonion had almost no influence. In combined genioplasty and Le Fort I procedures, the vertical changes at stomion inferius were 50% of those at menton + 1 mm upward movement, this difference being due to mandibular autorotation.

On the assets of CAD planning for craniosynostosis surgery

SkullWiz is a computer-aided design program that transforms computer tomographic data of the neurocranium into a mathematical model that can be interactively manipulated to plan craniosynostosis surgery. Proper planning of this type of surgery involves reference to the underlying viscerocranium and to normal neurocranial dimensions, simulation of all basic surgical actions (closed and open osteotomy, translation, rotation, bending, removal, burring), and reference to the mechanical properties of calvarial bone at a given age. With SkullWiz, infinite trials are possible to develop a surgical plan that combines minimal action with maximum morphologic result. In contrast, physical models, e.g., foam milled or stereolitographic, provide just a single (or double, after gluing) opportunity to visualize three-dimensional morphology and simulate a treatment plan, without reference support. Validation of SkullWiz is difficult due to parameter variability. Its assets are therefore graphically exemplified in two common types of nonsyndromatic single-suture craniosynostosis—trigonocephaly and anterior plagiocephaly. SkullWiz is one of the most accurate planning tools currently available for craniosynostosis surgery. Accurate transfer of the planning by aluminium templates results in efficient and precise surgery by avoiding per-operative “chipping and fitting.”

Orthognathic surgery: patients' subjective findings with focus on the temporomandibular joint

Two hundred and ninety-six patients who underwent various orthognathic surgery procedures were questioned, a minimum of 1 year postoperatively, on their overall subjective findings. Patient satisfaction, willingness to resubmit to surgery, self-confidence and subjective changes in their temporomandibular joints (TMJ) function and masticatory efficiency were evaluated. 87% would undergo the combined surgical-orthodontic treatment again. Self-confidence improved in 77% of the patients. There was a subjective improvement in TMJ function in 40% of the patients and a worsening in 11%; masticatory function was improved in 41% and worsened in 7% of the patients.