W. Zemann

Intraoperative control of resection margins in advanced head and neck cancer using a 3D-navigation system based on PET/CT image fusion

Local recurrent of disease in advanced carcinomas of the head and neck is strongly correlated with the presence of positive or close resection margins after operative treatment. The purpose of this study is to present a new method of assessing resection margins intraoperatively using image-guided surgery based on positron emission tomography/computed tomography (PET/CT) image fusion. In 6 patients who underwent surgical treatment of head and neck stage for T4a-T4b carcinomas PET/CT image fusion was done on the workstation of a 3D-navigation system. Intraoperative image-guided navigation of the defect following surgical ablation of the tumour was performed in every patient. Intraoperative navigation of the ablative defect showed an unsafe resection margin in 4 patients. In three of these patients additional image-guided resection allowed local control of the tumour to be achieved. In one patient additional resection was not possible due to skull base invasion. The histopathological exam of the four tumour specimens confirmed positive or close resection margins. The current results suggest that intraoperative control of the surgical margins using a 3D-navigation system based on PET/CT image fusion can be a useful tool to assess and improve local control in advanced cancer of the head and neck.

Primary osteomyelitis of the mandibular condyle—a rare case

Osteomyelitis is an inflammatory process involving cortical and cancellous bone. In the maxillofacial region, the mandible is the most frequently affected bone. In the vast majority, a bacterial focus can be identified as the origin of the disease. Chronic progress of the disease may lead to destruction of mandibular bony structures, resulting in mild or severe loss of function if no adequate treatment is applied. In some cases, the etiology of osteomyelitis remains unclear. Review of literature revealed two cases of necrosis of the mandibular condyle caused by primary osteomyelitis. We report a case of primary osteomyelitis of the mandibular condyle in a 51-year-old woman. Radiography revealed an almost complete destruction of the right mandibular condyle, resulting in malocclusion. The patient was treated with long-term antibiotics. No surgical intervention had been performed. After remission of the symptoms, the malocclusion had been corrected prosthetically. After a 4-year follow up period, the occlusion is stabile and there are no signs of progression of the disease.

Osteosynthesis using cannulated headless Herbert screws in mandibular angle fracture treatment: A new approach?

INTRODUCTIONnFractures of the mandibular angle are a common type of facial skull fracture. Although operative treatment includes a wide range of fixation techniques, a definite gold standard method has yet to be established. Headless, cannulated Herbert screws, often used in many forms of minimally invasive trauma surgery, provide functional and stable fracture fixation.nnnMATERIALS AND METHODSnIn a prospective, double-randomised, controlled, parallel-group - designed, inxa0vitro trial, the biomechanical behaviour of the Herbert bone screw system was compared to that of a conventional locking plate system in 40 mandibular angle fractures of human mandible cadaver phantoms.nnnRESULTSnThe mean stress values were 250 (±68.0) N in the plate subgroup and 200 (±61.0) N in the screw subgroup. The respective mean strain values were 7.90 (±2.7) mm and 6.90 (±2.2) mm, and the respective mean stiffness were values 1.10 (±0.61) N/m and 0.78 (±0.40) N/m. The differences in the results obtained using the two treatments were not significant (pxa0=xa00.55).nnnCONCLUSIONSnThe biomechanical behaviour of the two fixation systems within the tested loads did not significantly differ with respect to postoperative parameters clinically relevant in osteosynthesis. Both systems met the mandibular angle assessment criterion, which is considered to be sufficient for clinical use. The results indicate the potential clinical utility of these two systems, and recommend further testing.

Clinical experience with a novel structure designed bridging plate system for segmental mandibular reconstruction: The TriLock Bridging Plate

The innovative TriLock Bridging Plate System (Medartis AG, Switzerland) was developed to reduce common complications related to conventional mandibular reconstruction plates. The novelties regarding the plating system concern the cross-strut structure in the centerpiece, the bendable side elements and the reduction of the plates thickness to 2.0xa0mm 4 different models are available, which cover lateral and central segmental mandibular defects. The plating system has only been introduced at selected maxillofacial units so far and clinical assessment is still lacking. Thus, the aim of the study was to analyze the novel Bridging Plate system in terms of its clinical applicability, rate of trimming and postoperative outcomes in a first investigation over 6 months. The study includes 25 patients with segmental mandibular resection, who underwent reconstruction with TriLock Bridging Plates. According to the assessment parameters, excellent clinical applicability was stated in 48%. The overall trimming rate was found to be 88%. Mostly adaptions to the distal bendable elements of lateral plates were performed. The occurrence of postoperative complications was 16%. Plate fracture occurred in 4%. With reference to the results, the novel plating system represents a viable method for segmental mandibular reconstruction, however, further evaluation is needed, for a more detailed analyzation.

Anatomy of the Le Fort I segment: Are arterial variations a potential risk factor for avascular bone necrosis in Le Fort I osteotomies?

PURPOSEnOsteotomies of the Le Fort I segment are routine operations with low complication rates. Ischemic complications are rare, but can have severe consequences that may lead to avascular bone necrosis of the Le Fort I segment. Therefore the aim of this study was to investigate the blood supply and special arterial variants of the Le Fort I segment responsible for arterial hypoperfusion or ischemic avascular necrosis after surgery.nnnMATERIAL AND METHODSnThe arterial anatomy of the Le Fort I segments blood supply using 30 halved human cadaver head specimens was analyzed after complete dissection until the submicroscopic level. In all specimens the arterial variants of the Le Fort I segment and also the arterial diameters measured at two points were evaluated.nnnRESULTSnThe typical known vascularization pattern was apparent in 90% of all specimens, in which the ascending palatine (D1: 1,2xa0mmxa0±xa00,34xa0mm; D2: 0,8xa0mmxa0±xa00,34xa0mm) and ascending pharyngeal artery (D1: 1,3xa0mmxa0±xa00,58xa0mm; D2: <0,4xa0mm) were both supplying the Le Fort I segment. However in 10% of all specimens, the Le Fort I segment was dependent on the ascending pharyngeal artery alone and the missing ascending palatine artery was replaced with the anterior branch of the ascending pharyngeal artery (D1: 1,9xa0mmxa0±xa00,32; D2: 1,0xa0mmxa0±xa00,3xa0mm).nnnCONCLUSIONnThis study is the first description of a special type of arterial variation of the Le Fort I segment. The type of this arterial variation, its clinical relevance and potential consequences are explained. Individuals with this special arterial anatomy may clinically be at a high risk for hypoperfusion and avascular segment necrosis after surgery. An individualized operation plan may prevent ischemic complications in at-risk patients.

Assessment of tumor margins in head and neck cancer using a 3D-navigation system based on PET/CT image-fusion – a pilot study

OBJECTIVESnDetermination of tumor margins in patients with squamous cell carcinoma of the head and neck (SCCHN) is mostly based on preoperative magnetic resonance imaging (MRI) or computed tomography scans (CT). Local recurrence of disease is often correlated with the presence of positive resection margins after surgical treatment. Positron emission tomography/computed tomography (PET/CT) imaging plays a crucial role in the assessment of patients with SCCHN. The purpose of this study was to determine whether PET/CT could predict tumor extension.nnnMETHODSnIn 12 patients who underwent surgical treatment of primary SCCHN (Stage III-IV) F18-FDG PET/CT image-fusion was performed on a 3D navigation-system based workstation. Image-guided needle biopsies were obtained from four different, color-coded metabolic areas within the tumor. The histopathological findings were correlated with findings on corresponding PET/CT scans.nnnRESULTSn81.3% of biopsies from the central area were positive. Specimens taken from the outer metabolic zone were positive in 66.7% of the patients. The highest incidence of positive biopsies was found in the zone adjacent to the outermost area. There was a statistically significant difference in positive tumor histopathology when comparing the various metabolic zones (pxa0=xa00.03).nnnCONCLUSIONnExact determination of tumor is an important research topic, although results remain controversial. The results of this study suggest that in some cases PET scans may overestimate tumor extension.

Combining midfacial degloving, LeFort-I osteotomy and inferiorly extended lateral orbitotomy (Krönlein) for removal of an orbital cavernous haemangioma: a new approach

Orbital tumours, located in the medial extraconal and intraconal compartment of the orbit, represent a challenge, with regard to surgical exposure. In the present paper removal of a cavernous haemangioma, located in the medial intraconal compartment was accomplished by combining lateral orbitotomy, midfacial degloving and LeFort-I osteotomy. Resection of the tumour could be performed under direct vision. Surgical exposure and removal of the lesion were obtained, without causing damage to surrounding tissues. Aesthetical results and postoperative eye function proved to be highly satisfactorily. With regard to limitations, concerning the combination of these methods, extended surgery duration and invasiveness have to be named. According to the technical feasibility and postoperative results, this new surgical approach represents a reliable and fully viable alternative method for the removal of medial orbital tumours.