Shintaro Sukegawa

Long-Term Skeletal Stability After Maxillary Advancement With Distraction Osteogenesis in Nongrowing Patients

PURPOSE We assessed the long-term skeletal stability of the repositioned maxilla, midface in patients who underwent maxillary advancement using distraction osteogenesis (DO). PATIENTS AND METHODS The study included 19 nongrowing patients with maxillary hypoplasia with a Class III relationship, a normally developed mandible, and follow-up after DO exceeding 2 years. Eleven men and 8 women participated, with a mean age at treatment of 20.7 years (range 15.4-33.4 years). Twelve patients had midfacial hypoplasia associated with a cleft lip and palate (CLP), and 7 patients had developed noncleft-related hypoplasia. The surgical treatment included our modified Le Fort I osteotomy in combination with intraoral (5 cases) or extraoral (14 cases) distraction devices. Distraction was started after a latency period of 5 to 7 days and continued until the proper convexity was obtained. After active distraction, a 3- to 4-week period of retention was allowed, followed by rigid internal fixation (IF) with or without distractor removal. Lateral cephalometric films before midfacial distraction (T0), after IF with or without distractor removal (T1), 6 months after T1 (T2), and 2 or more years (mean 2.8 years) after T1 (T3) were analyzed. The maxillary A-point in the Frankfort horizontal reference plane was used to assess the skeletal changes in the maxillary position (x, y) at each time point (T1-T3). In addition, we analyzed the differences in the devices and techniques. RESULTS Midfacial DO was successful in all cases, resulting in a mean change obtained at point A of 10.3 mm (8.4 mm horizontally, 4.7 mm inferiorly). Point A underwent a moderate amount of skeletal relapse at T2 [0.4 mm (5%) horizontally and 0.6 mm (13%) superiorly], with a mean of 8% (0.6 mm) horizontally and 19% (1.0 mm) superiorly over the mean 2.8-year (2.0-4.8 years) follow-up. After long-term follow-up, the maxillary advancement with DO was stable in both CLP and non-CLP patients with maxillary hypoplasia. In addition, our original technique using a rigid external device provided the most reliable results in terms of skeletal stability. CONCLUSION This retrospective study showed that DO of the maxilla gives a very stable midface, offering a promising treatment alternative for patients with maxillary hypoplasia.

Clinical Evaluation of an Unsintered Hydroxyapatite/Poly-L-Lactide Osteoconductive Composite Device for the Internal Fixation of Maxillofacial Fractures

Introduction:OSTEOTRANS MX (Takiron Co, Ltd, Osaka, Japan) is a resorbable osteosynthetic material composed of an unsintered hydroxyapatite/poly-L-lactide composite, and its osteoconductive capacity has been documented. The authors here report their clinical experience using OSTEOTRANS MX. Methods:The authors treated 35 patients (19 men, 16 women; age, 14–88 years; mean ± standard deviation, 38.4 ± 19.9 years) with maxillofacial fractures. The authors used standard surgery to stabilize fractures in all patients, fitting resorbable plates (thickness, 1.0 or 1.4 mm) and screws (diameter, 2 mm) according to Arbeitsgemeinschaft für Osteosynthesefragen/Association (AO) for the Study of Internal Fixation guidelines. Results:All patients eventually achieved satisfactory healing with favorable restoration of form and function without foreign body reaction. Complications occurred in 3 patients—plate exposure in 2 and discomfort in 1. However, fracture sites healed in all patients. Scanning electron microscopy revealed that the devices bonded directly to the bone without interposition of nonmineralized tissue. Conclusion:OSTEOTRANS MX is a useful material with few complications. Its osteoconductive bioactivity is advantageous for the early functional improvement of maxillofacial fractures.

Submandibular Approach Through the Submandibular Gland Fascia for Treating Mandibular Fractures Without Identifying the Facial Nerve

BACKGROUND : The submandibular, or Risdon, approach is the classic, reliable extraoral approach for treating mandibular fractures. Although the intraoral approach has been used recently for open reduction and internal fixation, in some cases, such as comminuted fractures or fractures in an atrophic mandible, the submandibular approach is still prerequisite. Damage to the marginal mandibular branch of the facial nerve is the only concern other than skin scarring. METHODS : To minimize the risk of neuropraxia, we prospectively assessed an approach for treating mandibular fractures at 24 surgical sites in 22 patients (17 men, 5 women; mean age, 54.3 years) using direct submandibular gland capsule fascial layer elevation that did not require identifying the facial nerve. RESULTS : As complications, one patient (4.2%) had temporary facial weakness in the mandibular branch, but this resolved completely within 3 months. The postoperative clinical course was uneventful in the other patients with one minor fistula and minimal scarring. CONCLUSIONS : In conclusion, submandibular gland capsular layer elevation without facial nerve identification is a safe and less time-consuming technique applying the submandibular approach for the treatment of mandibular fractures.

The retromandibular transparotid approach for reduction and rigid internal fixation using two locking miniplates in mandibular condylar neck fractures

We evaluated the safety, efficacy, and morbidity associated with the treatment of displaced mandibular condylar neck fractures using a retromandibular transparotid approach to reduce and rigidly fix using two 2.0-mm locking miniplates. Our surgical inclusion criteria were: patient selection of open reduction and fixation, displaced unilateral condylar fractures with derangement of occlusion, and bilateral condylar fractures with an anterior open bite. The study group consisted of 19 patients who underwent surgery for 19 mandibular condylar neck fractures; patients were analyzed prospectively, with more than 6 months of follow-up, and were evaluated in terms of functional results, scar formation, postoperative complications, and stability of fixation. The results showed that functional occlusion identical to the preoperative condition and correct anatomical reduction of the condylar segments in centric occlusion, followed by immediate functional recovery, was achieved in all patients. No patient suffered from any major or permanent complication postoperatively, although there were two cases (11%) of temporary facial nerve palsy, which resolved completely within 3 months. Surgical scars were barely visible. The retromandibular transparotid approach with open reduction and rigid internal fixation for displaced condylar neck fractures of the mandible is a feasible and safe, minimally invasive surgical technique that provides reliable clinical results.

Locally Injected Dexmedetomidine Inhibits Carrageenin-induced Inflammatory Responses in the Injected Region

BACKGROUND:Dexmedetomidine, a highly selective agonist of &agr;2-adrenoceptors, is a commonly used sedative; however, a potent anti-inflammatory effect has also been found. In the present study we evaluated the inhibitory effect of locally injected dexmedetomidine on inflammatory responses in the injected region. METHODS:Local inflammation was induced in the hindpaws of male mice (aged 6–8 weeks) by intraplantar injection of lambda-carrageenin. To offset the central effect of tested agents, different agents were blindly injected into the left and right paws in the pairs of comparison. The effect of dexmedetomidine on edema (increase in paw volume), the accumulation of leukocytes, and production of tumor necrosis factor-&agr; (TNF-&agr;) and cyclooxygenase-2 (COX-2) were evaluated after carrageenin injection, using water displacement plethysmometry, histological imaging, immunohistochemistry, and Western blotting analysis. Furthermore, we also evaluated the effect of yohimbine, a full antagonist of &agr;2-adrenoceptors, and phenylephrine, an agonist of the &agr;1-adrenoceptor, on dexmedetomidine’s action on inflammatory responses. RESULTS:Paw volume and amount of leukocytes in the injected region significantly increased after the injection of carrageenin. Similarly, TNF-&agr; and COX-2 production was found in the subcutaneous region injected with carrageenin, 4 hours after injection. Dexmedetomidine significantly inhibited all increases in paw volume, leukocytes, and production of TNF-&agr; and COX-2. Furthermore, yohimbine significantly antagonized the anti-inflammatory effects of dexmedetomidine, whereas phenylephrine did not significantly alter them. CONCLUSIONS:The findings suggest that locally injected dexmedetomidine exhibits an anti-inflammatory effect against local acute inflammatory responses, mediated by &agr;2-adrenoceptors.

Transoral open reduction with rigid internal fixation for subcondylar fractures of the mandible using a small angulated screwdriver system: is endoscopic assistance necessary?

PURPOSE Although endoscopically assisted transoral open reduction and internal fixation of condylar mandible fractures is currently a popular technique, the need for it and its benefits remains unclear. This prospective study evaluated the efficacy and safety of open reduction and rigid internal fixation of subcondylar fractures of the mandible using a new small angulated screwdriver system without endoscopic assistance. PATIENTS AND METHODS Fifteen patients with 15 linear subcondylar fractures were treated using this intraoral approach from June 2007 through March 2010 at the Division of Oral and Maxillofacial Surgery, Kagawa Prefectural Central Hospital, Kagawa, Japan. The anatomic reduction of the displaced condylar segments and rigid fixation with 2 2.0-mm locking miniplates were performed using a small angulated screwdriver system, with an average follow-up of 13 months (range, 6 to 30 months). RESULTS Correct anatomic reduction of the condylar segments at centric occlusion followed by immediate functional recovery was achieved in all patients. Mean operating time was 50 minutes (range, 35 to 70 minutes) when performed by the consultant surgeon and the residents. In addition, all patients had good temporomandibular joint articular function, with no harmful clinical symptoms or deviation. CONCLUSIONS The surgical treatment of linear subcondylar fractures of the mandible can be achieved with an intraoral approach alone, using a small angulated screwdriver system, without endoscopic assistance, offering reliable clinical results and safe and minimally invasive surgery.

Computer-simulated bi-directional alveolar distraction osteogenesis

OBJECTIVES Computer-based surgical planning allows surgeons to evaluate bone morphology in three dimensions and to perform accurate virtual surgery preoperatively. This study was performed to evaluate the feasibility of using preoperative surgical simulation to enhance the clinical outcome in patients undergoing bi-directional alveolar distraction osteogenesis. MATERIAL AND METHODS Nine patients (mean age, 49 years; range, 20-61 years) with maxillary segmental alveolar defects following post-traumatic atrophy or disuse atrophy after periodontal tooth loss were enrolled in the study. All patients were scheduled for implant placement. Three-dimensional (3-D) morphological evaluation and virtual bi-directional distraction were performed with SimPlant CMF/OMS surgical simulation software (Materialise). In addition, use of an extraosseous bi-directional distraction device (V2-Alveolar Distraction System; Medartis AG) was evaluated during the 3-D alveolar regeneration simulation and resulting augmentation. RESULTS Alveolar height regeneration and labial-buccal augmentation were planned preoperatively using surgical simulation software. New bone formation with sufficient vertical augmentation of 5.8 mm was observed. As we encountered strong palatal inclination, the angulation required for labial-buccal augmentation during active distraction was the maximum angulation of 40 degrees , even greater than that required in the preoperative simulation of 23.9 degrees . Furthermore, the labial-buccal augmented angulation was gradually decreased to 11.2 degrees at the time of implant placement. In all cases, implantation was successful at the well-augmented sites, with sufficient primary stability after a 3-month consolidation period. CONCLUSIONS Preoperative 3-D simulation is a potentially valuable tool for treatment of the morphologically complicated oral-maxillofacial region. More realistic surgical simulations are anticipated with ongoing effort to collect and integrate clinical data into next-generation software.

Oral Rehabilitation of a Maxillectomy Defect Using Bone Transport Distraction and Dental Implants

Bone transport distraction is a reliable procedure in various maxillofacial bony defect reconstruction techniques. It is minimally invasive and it eliminates donor site morbidity. We introduce a new surgical technique for maxillary backward bone transport distraction reconstruction performed in a 77-year-old woman with a posterior partial maxillary defect. Transport distraction was successful for posterior maxillary alveolar bony regeneration, which helped close an oroantral fistula. One month after the distraction device was removed, 3 dental implants were placed in the reconstructed alveolus, followed by successful oral functional rehabilitation by use of an implant-anchored prosthesis. Two and a half years have passed since the patients dental implant-based prosthesis was activated, and the functional occlusal reconstruction by use of bone transport distraction and dental implants after repair of the maxillectomy defect has proven to be effective with patient satisfaction.

Mandibular fracture patterns consistent with posterior maxillary fractures involving the posterior maxillary sinus, pterygoid plate or both: CT characteristics.

OBJECTIVES The aim of this study was to determine the incidence of posterior maxillary fractures involving the posterior maxillary sinus wall, pterygoid plate or both, unrelated to major midface fractures in patients with mandibular fractures, and to characterize associated fractures. METHODS A CT study was performed in patients with mandibular fractures to identify posterior maxillary fractures. Patients aged under 16 years, those with mandibular fractures involving only dentoalveolar components and those with concurrent major midfacial fractures were excluded. RESULTS 13 (6.7%) of 194 patients with mandibular fractures also had posterior maxillary fractures (case group). The injury pattern correlated with the external force directed to the lateral side of the mandible (p < 0.001), alcohol consumption (p = 0.049), the presence of multifocal fractures (p = 0.002) and the fracture regions in the symphysis/parasymphysis (p = 0.001) and the angle/ramus (p = 0.001). No significant difference between the case and non-case groups was seen for age, sex or cause of trauma. Non-displaced fractures in the ipsilateral posterior mandible occurred with significant frequency (p = 0.001) when the posterior maxillary fractures involved only the sinus. CONCLUSIONS Mandibular fractures accompanied by posterior maxillary fractures are not rare. The finding of a unilateral posterior maxillary fracture on CT may aid the efficient radiological examination of the mandible based on possible patterns of associated fractures, as follows: in the ipsilateral posterior region as a direct fracture when the impact is a medially directed force, and in the symphysis/parasymphysis or contralateral condylar neck as an indirect fracture.

Simultaneous Sinus Lifting and Alveolar Distraction of a Severely Atrophic Posterior Maxilla for Oral Rehabilitation with Dental Implants

We retrospectively reviewed a new preimplantation regenerative augmentation technique for a severely atrophic posterior maxilla using sinus lifting with simultaneous alveolar distraction, together with long-term oral rehabilitation with implants. We also analyzed the regenerated bone histomorphologically. This study included 25 maxillary sinus sites in 17 patients. The technique consisted of alveolar osteotomy combined with simultaneous sinus lifting. After sufficient sinus lifting, a track-type vertical alveolar distractor was placed. Following a latent period, patient self-distraction was started. After the required augmentation was achieved, the distractor was left in place to allow consolidation. The distractor was then removed, and osseointegrated implants (average of 3.2 implants per sinus site, 80 implants) were placed. Bone for histomorphometric analysis was sampled from six patients and compared with samples collected after sinus lifting alone as controls (n = 4). A sufficient alveolus was regenerated, and all patients achieved stable oral rehabilitation. The implant survival rate was 96.3% (77/80) after an average postloading followup of 47.5 months. Good bone regeneration was observed in a morphological study, with no significant difference in the rate of bone formation compared with control samples. This new regenerative technique could be a useful option for a severely atrophic maxilla requiring implant rehabilitation.