Ralf Schön

Navigational maxillofacial surgery using virtual models.

Ablative tumor surgery and orbital and midface reconstruction, as much as orthognathic surgery, requires detailed planning using computed tomography (CT) or magnetic resonance imaging (MRI). These techniques also allow simulation of complex surgeries preoperatively. Proper reconstruction depends on reliable information to choose the correct type of grafts and to predict the outcome. This study evaluates the benefit and indications of computer-assisted surgery in the treatment of 107 patients who underwent craniomaxillofacial surgery. Based on a CT or MRI data set, an optical navigation system was used for preoperative planning, intraoperative navigation, and postoperative control. Surgery could be preoperatively planned and intraoperatively navigated. Preoperatively, it required that soft and hard tissues were measured using the mirrored data set of the unaffected side; the size and location of the graft were chosen virtually. Intraoperatively contours of transplanted tissues were navigated to the preoperatively simulated reconstructive result. Computer-assisted treatment was successfully completed in all 107 cases. Preoperatively outlined safety margins could be exactly controlled during tumor resection. Reconstruction was designed and performed precisely as virtually planned. Image-guided treatment improves preoperative planning by visualizing the individual anatomy, outlining the intended reconstructive outcome, and by objectifying the effect of adjuvant therapy. Intraoperative navigation makes tumor and reconstructive surgery more reliable by showing the safety margins, saving vital structures, and leading the reconstruction to preoperatively planned objectives.

Five-year retrospective study of mandibular fractures in Freiburg, Germany: incidence, etiology, treatment, and complications

PURPOSE To evaluate current trends in maxillofacial trauma, a retrospective review of mandibular fractures at a German university hospital was carried out. PATIENTS AND METHODS In this retrospective study, records of 444 patients with mandibular fractures between 2000 and 2005 at the Department of Oral and Maxillofacial Surgery, University Hospital of Freiburg, Germany, were reviewed. A total of 444 patients presented with 696 mandibular fractures. RESULTS Three hundred twenty-nine (74%) of the fractures occurred in male and 115 (26%) in female patients (2.9:1). One hundred forty-two fractures (32%) resulted from road traffic accidents, 126 from fights (28%), and 116 from falls (26%). Forty-four fractures were caused by sport accidents (10%) and 16 by pathologic fractures (4%). The mandibular condyle area was the most common fracture site, with 291 fractures (42%), followed by 144 fractures of the symphyseal and parasymphyseal area (21%) and 141 angle fractures (20%). Combined fractures were found in nearly half of the cases. Five hundred seventy-nine (83%) of patients with mandibular fractures were treated by surgical intervention, 117 (17%) of patients conservatively. Regarding the surgical treatment, 561 (65%) miniplates, 247 (29%) locking plates, and 51 (6%) lag screws were used. Complications, such as postoperative infections, abscesses, and osteomyelitis appeared in 66 (9%) cases. CONCLUSION We concluded that osteosynthesis of mandibular fractures by miniplates and locking plates are both reliable.

Patient benefit from endoscopically assisted fixation of condylar neck fractures--a randomized controlled trial.

PURPOSE Owing to the risk of facial nerve damage and the creation of visible scars, surgical treatment of condylar mandible fractures using an extraoral approach remains controversial. The transoral endoscopically assisted approach of condylar fractures has been reported to avoid these complications. A prospective, randomized controlled, multicenter trial was performed to quantify the patient benefit after open reduction and internal fixation of condylar mandible fractures using endoscopically assisted treatment compared with surgical treatment without endoscopic assistance. PATIENTS AND METHODS Patients with dislocated uni-/bilateral condylar neck fractures were randomized to receive either nonendoscopic open reduction and internal fixation using an extraoral (submandibular, preauricular, retromandibular) approach or a transoral endoscopic procedure. The primary functional outcome measure was investigated using the asymmetric Helkimo dysfunction score at 8 to 12 weeks and 1 year after surgery. RESULTS A total of 74 patients were recruited between 2003 and 2006; the nonendoscopic extraoral group included 34 patients and the endoscopically assisted open reduction group included 40 patients. Comparable functional results were noted in both groups without any statistical significance. Endoscope-assisted treatment proved to be more time consuming. For the extraoral group, visible scars were rated by most of these patients as being cosmetically acceptable; however, a greater number of facial nerve injuries were reported. CONCLUSIONS The treatment of condylar mandible fractures with a minimal invasive endoscopically assisted technique is reliable and may offer advantages for selected cases, particularly concerning the lower occurrence of facial nerve damage.

Semiautomatic procedure for individual preforming of titanium meshes for orbital fractures.

Background: Three-dimensional reconstruction of the orbital floor is a key procedure in primary or secondary orbital deformity. A new procedure for individually bending and preforming implants preoperatively for the reconstruction of orbital fractures is presented. Methods: By using diagnostic computed tomographic scan data, the topography of the orbital floor and wall structures can be recalculated. After mirroring the unaffected side onto the affected side, the defect can be reconstructed virtually. Data of the individual virtual model of the orbital cavity are sent to a template machine that reproduces the surface of the orbital floor and medial walls automatically. A titanium mesh can then be adjusted preoperatively for exact three-dimensional reconstruction. Twelve patients with orbital fractures were treated using individually preformed titanium implants. Results: All patients treated with this procedure showed normal eye mobility and function after primary reconstruction. The accuracy of the preformed implants lies in the range of 1 mm. Conclusions: This procedure offers an individual anatomical reconstruction of the orbital cavity true to original, especially when the deep orbital cone is affected. Navigation-aided procedures guarantee intraoperatively an exact placement of the preformed mesh even for precise reconstruction of extensive orbital defects.

The development of plate osteosynthesis for the treatment of fractures of the mandibular body : A literature review

PURPOSE Today plate and screw osteosynthesis of mandibular fractures is a standard procedure in routine clinical practice. In this review, the breakthroughs and drawbacks of the development of this important aspect of maxillofacial surgery are followed-up. METHODS Medline search of relevant English and German literature. RESULTS In 1886, Carl Hansmann was the first who applied steel screws and plates. Until today the material, the types of plates and applications have been continually improved. Over the last two decades miniplate osteosynthesis has induced a revolution in mandibular fracture treatment. The modern systems provide better handling, higher stability and less pressure on the bone. CONCLUSION Modern miniplates have great advantages, like the intra-oral approach and the easy adaptability. In addition, it is no longer necessary to expose bone as extensively.

Swallowing and speech function after intraoral soft tissue reconstruction with lateral upper arm free flap and radial forearm free flap.

Swallowing, speech, and morbidity were assessed postoperatively in 25 patients, 18 of whom had had intraoral defects reconstructed by lateral upper arm free flaps (LUFF) and 7 by radial forearm free flaps (RFFF). Video fluoroscopy was used to assess swallowing, the Freiburger audiometric test to assess speech; and measurement of arm circumference to assess donor site morbidity. A questionnaire was used to evaluate swallowing, speech, and donor site morbidity subjectively. The degree of impairment in swallowing depended on the site of resection. Anterior and posterior resections affected swallowing more than lateral resections. Anterior resection and the use of LUFFs reduced intelligibility. There was no significant difference in impairment between LUFF and RFFF. We conclude that the LUFFs are superior to RFFFs because they can be closed primary and the incidence of donor site morbidity is slight.

Color duplex sonography for the monitoring of vascularized free bone flaps

OBJECTIVE When vascular complications are suspected after the microsurgical transfer of free buried fibular bone flaps without a skin island, revision surgery often proves to be unnecessary. We sought to determine the efficacy of color duplex sonography in the close observation of bone graft patency postoperatively. Study design Twelve free fibular bone flaps without a skin island were postoperatively monitored through color duplex sonography with a 7.5-MHz scanner. RESULTS With color duplex sonography, the rate of perfusion in the vascular pedicle could be visualized in all 12 fibular flaps. In 3 patients, vascular complications and flap failure were suspected. However, because adequate perfusion of the vascular pedicle was observed immediately after surgery and in the daily follow-up examinations, revision surgery was not necessary. CONCLUSIONS Color duplex sonography is not time-consuming; in fact, it is a reliable, noninvasive, and inexpensive method for the postoperative monitoring of free bone flaps.

Frontiers in maxillofacial endoscopic surgery.

The use of endoscopically assisted techniques allows limited incisions for the open reduction of condylar process fractures. Intraoperative control after fracture reduction in areas of limited exposure and visibility is possible. In addition, the risk of facial nerve damage and extensive visible scars can be reduced by using minimally invasive endoscopic techniques. Although the use of endoscopically associated techniques in maxillofacial surgery offers many options and advantages, indications for open treatment of maxillofacial trauma have not changed. The repair of severely dislocated and comminuted fractures of the facial skeleton and major reconstruction of craniomaxillofacial structures still require extended exposure with traditional intraoral and extraoral approaches.

Preformed titanium meshes: a new standard?

Three-dimensional reconstruction of the orbital floor is the key procedure for a primary or secondary orbital deformity. After the unaffected side is mirrored onto the affected side using the patients computer-tomography database, the defect can be reconstructed virtually. A measurement procedure that calculates the virtually reconstructed orbital surface data is available. These data are sent to a template machine that reproduces the physical surface. A flat titanium mesh can then be adjusted preoperatively to the spatial configuration of the anatomical structures. This procedure offers optimal anatomical reconstruction of the orbital floor, especially when the deep orbital cone is affected.

Long-Term Survival of Dental Implants Placed in the Grafted Maxillary Sinus: Systematic Review and Meta-Analysis of Treatment Modalities

Background A prevalent modality to increase the amount of available bone prior to implantation is grafting of the maxillary sinus. Multiple factors such as the surgical technique, moment of implant placement as well as grafting materials and membranes are known to affect implant survival. However, the role of different factor combinations and associated reciprocal effects remain unclear. Conventional statistical methods do not consider inconsistency of study designs and do not take covariables into account. Hence, a systematic research and meta-analysis was conducted to investigate the influence of various treatment modalities on implant survival in the grafted maxillary sinus. Materials and Methods A meta-analysis was conducted according to the PRISMA guidelines. Articles published from 1980 through January 2013 were electronically and manually searched in MEDLINE (Ovid), the Cochrane Register of Controlled Trials, the Database of Abstracts of Effects, and the Cochrane Database of Systematic Reviews. Clinical reports on single intervention sinus augmentation with root-form implants, a minimum of 10 patients and 6 months of loading were eligible for inclusion if implant survival was stated or calculable. Results were calculated by non-parametric univariate Kaplan-Meier analysis and Bayesian multivariate interval-censored Cox regression. Results A total of 122 publications on 16268 endosseous implants placed in grafted maxillary sinus were included. The treatment parameters surgical approach, grafting material and implant type showed no selective preference. However, application of membranes showed a significantly reduced hazard-ratio, independent of other co-factors. Conclusions The use of membranes is the most significant factor to achieve long-term implant survival in sinus augmentation procedures. More data exceeding 3 years follow-up are needed to address prospective confounding and improve clinical evidence.