Surgical treatment of synovial chondromatosis of the temporomandibular joint with erosion of the skull base: a case report and review of the literature.

Synovial chondromatosis (SC) is a rare metaplastic disease of the larger joints. It is rarely observed in smaller joints, especially in the temporomandibular joint (TMJ). This disease is considered to be metaplastic and shows no malignant tendencies, but can become locally aggressive, erode the cranial base, and even spread intracranially. To date, nine cases of spread into the intracranial space have been reported in the literature; however, the disease remained extradural in all cases. The authors present a review of the literature and report the case of a 70-year-old man with SC of the right TMJ that had eroded the cranial base, reaching the dura mater; a large intracranial mass was not present. The disease was considered to be stage 3 according to Milgram's classification. The patient was treated surgically, the tumour mass was removed, reconstruction of the cranial base was performed using titanium mesh, and the joint was reconstructed with a temporal muscle interposition flap. Diagnostic images and intraoperative photographs are also presented.

Surgical treatment of macroglossia caused by systemic primary amyloidosis.

Amyloidosis is a heterogeneous group of disorders caused by the extracellular deposition of a fibrillar protein called amyloid. Amyloid involvement of the tongue is almost universally secondary to systemic disease. The clinical manifestations result from the progressive extracellular deposition of amyloid within the suprahyoid muscles. In the late stages, the progressive enlargement of the tongue causes hypo- and oropharyngeal blockage, with obstruction of the upper airways. Conservative excision is a satisfactory treatment for local amyloid masses; the role of surgery in systemic forms is controversial. The authors present a case of systemic primary amyloidosis of the tongue treated surgically by a partial glossectomy via a pull-through approach and discuss the indications and rationale for surgical intervention.

Surgically assisted rapid maxillary expansion: feasibility of not releasing the nasal septum.

Surgically assisted rapid maxillary expansion (SARME) is commonly used to correct maxillary transverse deficiency. The aim of this study was to analyse the need for intraoperative liberation of the nasal septum during the procedure. SARME was performed in 25 patients by combining a lateral osteotomy with an inter-radicular maxillary osteotomy. The deviation of the nasal septum after SARME was evaluated by comparing measurements between radiologically defined landmarks on pre- and postoperative computed tomographic images. Two defined angles (angle I, between crista galli-symphysis mandibulae and crista galli-septum nasi; angle II, between maxillary plane and septum nasi) were measured based on four representative planes and septal movement was analysed. The mean changes in angles I (0.03° ± 0.78°) and II (0.25° ± 1.04°) did not differ significantly from zero (p=0.87 and p=0.24, respectively). Observed variations and displacements were considered to be acceptable because they were insignificant in every respect. Intranasal airway function was also examined pre- and postoperatively to evaluate any loss of ventilation. The described surgical technique is a successful method of maxillary segment distraction. The authors found no compelling reason to release the nasal septum in the context of SARME.

Trans-tragal incision for improved exposure of diacapitular and condylar neck fractures.

The authors present a modification of the preauricular approach that improves the exposure of the condyle whilst reducing diacapitular and condylar neck fractures. The incision is a combination of the hockey-stick and endaural incisions. Its inferior part runs within the ear on the posterior face of the tragus; the tragal cartilage is transected together with the retrotragal skin and included in the anterior skin flap. Between May 2009 and December 2010, 16 patients with diacapitular or condylar neck fractures were treated with this approach. All patients showed good occlusion postoperatively and satisfactory aesthetic results. No infection or cartilage necrosis was observed in this series. This approach improves the exposure of the condylar head during the reduction of diacapitular and condylar neck fractures, ensuring easier internal fixation and good cosmetic results.

Removal of a pellet from the left orbital cavity by image-guided endoscopic navigation.

In the cranio-maxillofacial field, computer-aided surgery based on computed tomography data is becoming increasingly important. Complex surgical procedures can be performed utilizing preoperative imaging to provide real-time localization of surgical instruments in the surgical field. Image-data-based navigation plays an ever-increasing role in cases of minimal invasive surgery. The case is presented here of a 58-year-old male patient referred after a hunting accident with a pellet in the left orbit. After transferring the preoperatively acquired computed tomography data to a commercially available navigation system, the bullet was removed through the original wound canal using an intraoperatively calibrated high-resolution endoscope.

Cardiac metastasis after squamous cell carcinoma of the oral cavity: case report.

A 58-year-old woman presented with respiratory problems 6 months after she had had a squamous cell carcinoma in the oral cavity resected. We found on computed tomography a large lesion in the cardiac muscle. There were no abnormalities in the electrocardiogram. The patient died 7 days later and necropsy confirmed a solitary metastasis in the myocardium that originated from a squamous cell carcinoma of the mouth.

Extraosseous schwannoma of the mental nerve clinically simulating intraosseous.

We report a case of a benign neurilemmoma arising from the right mental nerve. Schwannomas are rare neurogenic tumours that originate from Schwann cells of the peripheral nervous system. Frequent locations are the head and neck region. Most of the tumours occur in the soft tissue whereas intraosseous schwannomas are rare. This case report deals with a young patient who was referred to our hospital with an unidentified fast-growing tumour located mainly in the premolar region of the right mandible. The tumour presented as an expansive, unilocular, well defined, radiolucent lesion on orthopantomography. No expansion of the mandibular canal could be seen. Computerized tomography scans of the mandible helped to identify the solid nature of the tumour. A biopsy was necessary to make the final diagnosis and the tumour was then excised surgically. Postoperative magnetic resonance imaging scans and a histological examination of the surgical specimen showed no signs of neurofibromatosis type 2.

Exploring the molecular basis for mechanosensation, signal transduction, and cytoskeletal remodeling.

Living cells respond to mechanical stimulation in a variety of ways that affect nearly every aspect of their function. Such responses can range from changes in cell morphology to activation of signaling cascades and changes in cell phenotype. Although the biochemical signaling pathways activated by mechanical stimulus have been extensively studied, little is known of the basic mechanisms by which mechanical force is transduced into a biochemical signal, or how the cell changes its behavior or properties in response to external or internal stresses. One hypothesis is that forces transmitted via individual proteins either at the site of cell adhesion to its surroundings or within the stress-bearing members of the cytoskeleton cause conformational changes that alter their binding affinity to other intracellular molecules. This altered equilibrium state can subsequently either initiate a biochemical signaling cascade or produce more immediate and local structural changes. To understand the phenomena related to mechanotransduction, the mechanics and chemistry of single molecules that form the signal transduction pathways must be examined. This paper presents a range of case studies that seek to explore the molecular basis of mechanical signal sensation and transduction, with particular attention to their macroscopic manifestation in the cell properties, e.g. in focal adhesion remodeling due to local application of force or changes in cytoskeletal rheology and remodeling due to cellular deformation.

Force-induced focal adhesion translocation: effects of force amplitude and frequency.

Vascular endothelial cells rapidly transduce local mechanical forces into biological signals through numerous processes including the activation of focal adhesion sites. To examine the mechanosensing capabilities of these adhesion sites, focal adhesion translocation was monitored over the course of 5 min with GFP-paxillin while applying nN-level magnetic trap shear forces to the cell apex via integrin-linked magnetic beads. A nongraded steady-load threshold for mechanotransduction was established between 0.90 and 1.45 nN. Activation was greatest near the point of forcing (<7.5 microm), indicating that shear forces imposed on the apical cell membrane transmit nonuniformly to the basal cell surface and that focal adhesion sites may function as individual mechanosensors responding to local levels of force. Results from a continuum, viscoelastic finite element model of magnetocytometry that represented experimental focal adhesion attachments provided support for a nonuniform force transmission to basal surface focal adhesion sites. To further understand the role of force transmission on focal adhesion activation and dynamics, sinusoidally varying forces were applied at 0.1, 1.0, 10, and 50 Hz with a 1.45 nN offset and a 2.25 nN maximum. At 10 and 50 Hz, focal adhesion activation did not vary with spatial location, as observed for steady loading, whereas the response was minimized at 1.0 Hz. Furthermore, applying the tyrosine kinase inhibitors genistein and PP2, a specific Src family kinase inhibitor, showed tyrosine kinase signaling has a role in force-induced translocation. These results highlight the mutual importance of force transmission and biochemical signaling in focal adhesion mechanotransduction.

18F-FDG PET: early postoperative period of oro-maxillo-facial flaps.

AIM: We addressed the feasibility of FDG-PET to differentiate between viability and non-viability in the immediate postoperative assessment of flaps (autologous microvascular anastomosed pedicled flaps) in oro-maxillo-facial surgery. METHODS: 3-7 days after surgery, FDG-PET was done in 38 patients who had received flaps for re-construction of the mandible after partial resection. The studies were done on a dedicated full ring PET-scanner (ECAT EXACT HR+, Siemens/CTI). Acquisition started between 60 and 80 min post injection. The findings of the soft tissue component of the flaps were grouped using a three point scale: (I) no defect, (II) small defects, (III) one large defect. The results of PET were compared with the clinical course for at least 3 months. RESULTS: "No defect" on the FDG-PET study identified vi-ability of the flap and predicted normal clinical follow-up (22/38 patients). "Small defects" visualized areas of decreased perfusion and decreased glucose metabolism indicating risk of non-viability (13/38 patients); adapt-ing the postsurgical management led to delayed but uncomplicated healing of the flaps in these patients. "One large defect" demonstrated early necrosis of the flap (3/38 patients). After removal and replacement of this necrotic portion of the flap the second FDG-PET scan of these 3 patients demonstrated the uncomplicated post-operative healing. CONCLUSION: FDG-PET facilitated the assessment of viability and non viability of flaps in the immediate postsurgical period, and demonstrated the usefulness of FDG-PET for postoperative care and prognosis.

Analysis of midface asymmetry in patients with cleft lip, alveolus and palate at the age of 3 months using 3D-COSMOS measuring system.

INTRODUCTION: Patients suffering from unilateral cleft lip, alveolus and palate exhibit a varying degree of asymmetry of the midface. Evaluation of this asymmetry can be carried out by means of 3D-CT, or a laser surface scanner. MATERIAL AND METHODS: In this paper, 3D-CT-scan data of 21 patients with unilateral clefts of lip, alveolus and palate were analysed using three-dimensional models. Evaluations of the 3D-models were carried out with the computer-aided 3D-operation simulator 3D-Cosmos. RESULTS: Asymmetry was found in the orbital, nasal and maxillary regions. The infraorbital rims were displaced craniocaudally and horizontally as well as laterally of the cleft-sided piriform aperture. This asymmetry corresponded to a dislocation of the maxillary segment on the cleft side. A deficit in volume was not reliably found.

Immediate alveolar ridge distraction after tooth extraction--a preliminary report.

Seven patients with severe periodontitis that had resulted in loss of alveolar ridge bone were treated by tooth extraction followed by immediate insertion of an implant distraction device. After successful distraction and bony healing the implant was used to fit a prosthesis.

The Graz implant supported pendulum, a technical note.

A new, immediately loadable palatal implant with rotational stability and an implant-supported pendulum for patients with dental class II dysgnathia and dental crowding is presented. In seven cases, the treatment goal of distalization of all upper molars without extraction of a single tooth was achieved within 8 months.

Vascularized versus non-vascularized nerve transfers: histologic study in rats.

From the clinical point of view, the state of vascularized nerve transfers is clearly demonstrated in the literature. This study was carried out to elicit the basic histologic differences between vascularized and non-vascularized nerve transfers in an animal experiment. In 46 rats, the lateral femoral cutaneous nerve was resected, and an interposition with a free (n=23) ischiatic nerve transfer on one side and a vascularized (n=23) ischiatic nerve transfer on the other side was carried out. Three months postoperatively, the rats were sacrificed and 45 nerve transfers and 46 contralateral reference specimen probes were histologically evaluated. A lower degree of nerve fibrosis and vesicular degeneration of the myelin sheath were found in the vascularized nerve transfers, compared to the free non-vascularized transfers. The thickness of the myelin sheaths was less in the free transfers. From a histologic point of view, a lower degree of degenerative changes was seen in the vascularized nerves after transfer.

[Stability of dental implants in microvascular scapula and iliac crest transplants]. / Stabilität dentaler Implantate in mikrovaskulären Skapula- und Beckenkammtransplantaten. Vergleichsstudie.

STUDY: In this study 24 patients with tumours of the mandible, mandibular resection, neck dissection and reconstruction by microvascular iliac crest (13) or scapula transplants (11) were examined following implantological treatment. RESULTS: In all patients the implantological examination was performed on average two years and five months after implant insertion. This allowed for observation of periotest values, periimplant probing depth and sulcus bleeding (SBI). Furthermore, the loss of periimplant bone was registered radiologically. In both groups periotest values were normal. In the group with scapular transplants the mean periotest value was -3.2 and in the other group -0.8. Pathological probing depth was registered in both groups and sulcus bleeding was similar. The loss of periimplant crestal bone was similar in both groups, too. DISCUSSION: It can thus be concluded that perimimplant conditions were equal in both groups two years after implant loading. The stability of implants in scapula transplants was higher than in iliac crest transplants.

Navigational precision of drilling tools preventing damage to the mandibular canal.

PURPOSE: The use of CT-based intraoperative navigation has greatly improved surgical control in many specialities. In this study the precision of the SMN system (Zeiss, Oberkochen, Germany) for navigated drilling before implant insertion is evaluated. MATERIAL AND METHOD: One hundred test drillings were carried out on 10 standardized acrylic lower jaw models with the aid of the navigation system after CT scanning. The CT scans were taken using a slice thickness of 1 mm. Then the CT data were transferred to the workstation of the SMN system and referentiation with the help of reference points (fiducials) of the mandibular models for superposition of the acrylic and the CT models were carried out. Referentiation of the model and the drilling were performed by a drilling tool. The limit of drilling was the upper border of the mandibular canal. The aim was to come as near as possible without perforation of the canal roof. RESULTS: An average drilling depth of 6.23 mm and a mean distance to the mandibular canal of 0.14 mm (s=0.05) was found. In 11 cases the upper border of the canal was perforated. The average penetration of the mandibular canal measured 0.19 mm. Eighty-nine drill holes were accomplished without perforation. The average distance to the alveolar canal measured 0.13 mm. CONCLUSION: A high precision of CT-based navigation for controlled drilling of mandibles for dental implants was seen.

Computer assisted tumour resection of the skull base: case report.

This case report demonstrates computer assisted resection of a skull base tumour after combined chemotherapy and irradiation, in a 40-year-old man with a squamous cell carcinoma of maxilla, zygoma, orbit and skull base. The resection of the skull base was performed with computer assistance after conventional resection of the maxilla, midface, exenteration of the orbit and lymph node dissection. Following combined chemotherapy and irradiation, the original, pretherapeutic tumour extent was marked on the new, presurgical CT scan enabling resection of the skull base with the use of a navigation microscope. Thus planned resection from the presurgical CT could be transposed intraoperatively using the navigation system, and the skull base could be resected with precision.

[Histological and histomorphometric results of implantation of dental implants by early and late implantation]. / Histologische und histomorphometrische Ergebnisse der Implantation dentaler Implantate bei Früh- und Spätimplantation.

In this study, a histologic and histomorphometric analysis of delayed and immediate-placed implants was performed. An implantation of 16 self-cutting conical titanium screw implants was carried out in 8 beagle dogs. Of these implants, 8 were placed immediately after extraction of the second premolar and 8 implants were placed after 6 months of healing after extraction. For dynamic histomorphometry, fluorochrome bone markers were injected at two different times prior to euthanasia. The specimens were examined macroscopically and microscopically 8 months after implantation. A histologic, dynamic, and static histomorphometry was performed with the aid of different computer programs. A mean surface of osseointegration of 75.7% and a mean soft tissue implant contact surface of 24.2% was seen in immediate-placed implants. For delayed implantation, an osseointegrated surface of 80.7% and a soft tissue covering of 19.3% was examined. The fibrogenic structures in the cervical implant part were more dense and there were more adhesive epithelial elements (hemidesmosomes) around delayed implants. The result of the dynamic and static histomorphometry showed no significant differences in the two groups (P < 0.1). In conclusion, it can be stated that a new steady-state of the soft and hard tissue around dental implants was seen 8 months after implant insertion in both groups. There was a pseudoankylotic healing in the osseous part. The lower level of osseointegration in immediate-placed implants was caused by early resorption of bone in the crestal part. Thus, a larger part of the implant was surrounded by soft tissue and a long epithelial attachment resulted.