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Background: Whether surgical nerve decompression is indicated for the treatment of posttraumatic reduced vision with optic nerve compression in the bony canal has been a subject of controversy for decades. On balance, the recent literature suggests that this procedure is indeed indicated, as a supplement to high-dosed cortisone therapy. The risk of surgery-related side effects is usually rated low in the literature., Case Report: We report on a woman patient in whom craniocerebral trauma involved a fracture of the left optic canal with unilateral loss of vision. In the decompression operation, intraoperative symptoms gave rise to the suspicion of an arteriovenous fistula, which had not been revealed by computer tomography and which was seen as sufficient grounds for discontinuing the procedure. In addition to a carotid artery-sinus cavernosus fistula (CCF Barrow type A), subsequent angiography revealed a dissected aneurysm at the branching of the occluded ophthalmic artery., Discussion and Conclusions: In decisions on whether surgical relief of pressure on the optic canal is indicated after trauma-related visual loss, the possibility of secondary lesions near the tip of the orbita and the optic canal must be taken into account. These are not always revealed by computer tomography. The indications should be critically weighed up in each individual case, with additional imaging examinations, such as MR-angiography, CT-angiography, or conventional angiography, performed as needed. The options and indications for imaging are discussed. The procedure can by no means be rated as "minimally invasive", as is postulated by some authors.

Background: The application of computer assisted procedures in orbital surgery is made more difficult by the intraoperative tissue shift in intraorbital structures, since this intraoperative dislocation cannot be imaged in preoperative CT/MR datasets., Methods: After preoperative recording of CT and/or MR datasets in five patients with orbita affected by frontobasal tumors, we used intraoperative sonography by coupling the ultrasound unit to the navigation system., Results: Registration, referencing and calibration of the ultrasound system proceeded without any difficulties. Intraoperatively, the structures of the anterior and middle thirds of the orbita and their tissue shift could be particularly well evaluated sonographically., Conclusion: The use of navigated sonography enables repeated intraoperative re-evaluation of preoperative CT/MR datasets. The fusion of intraoperative sonography with preoperative imaging visualizes the tissue shift and facilitates the identification of anatomical structures and the spatial orientation of the surgeon. This appears to allow both increased operative radicality and greater tissue protection. In our opinion, the intraoperative parallel application of a non-calibrated ultrasound system and an only CT/MRT based navigation system cannot fulfill these requirements because of anatomical complexity.

Background: Multimodal strategies are required due to the poor prognosis for locally advanced frontal skull base tumors staged as T4. Therefore, a further increase in the degree of invalidity caused by therapy should be avoided, if possible, to preserve the quality of life. As the incidence of these tumors is low, there are no evidence-based, generally accepted therapeutic strategies., Methods: We evaluated the clinical results of three patients with extended frontal skull base malignomas staged as T4 tumors. The clinical course as well as the surgical technique were analyzed., Results: High dose neoadjuvant therapy for tumor downsizing was performed in all three patients within a multimodal therapy concept. The additional space for surgical manipulation close to the tumor borders, non-traumatically produced by tumor remission, permitted a safely navigated, controlled resection of the tumor under endoscopic or microscopic viewing using an approach associated with reduced trauma as "targeted surgery"., Conclusions: Surgical radicality is limited by the direct vicinity of locally progressive T4 tumors to the frontal brain and other vital structures. A controlled tumor downsizing allows the resection of such tumors using a minimally invasive approach assisted by instrumental navigation leading to less traumatization.

Background: Virtual model analysis of patient head tracking allows for objectivity and the monitoring of therapeutic results of pathologies in the skull base region. The introduction of these models in clinical routine has been impaired by the extended time needed for the preparation of radiological data., Methods: Quality control analysis was carried out for seven cases with different pathological findings in the skull base region in patients who had undergone virtual model analysis., Results: Preparation time of radiological data for the process of segmentation required, under optimal conditions, a minimum of 30 min. Virtual model analysis enables spatial visualization of regions of interest and adjacent anatomical structures. This improves case-specific pathoanatomical understanding as well as preoperative planning of surgical strategies., Conclusions: Virtual model analysis improves the physician's spatial comprehension of localized pathological findings at the dysmorphic interface of bone and soft tissue across the skull base. Therefore, it seems to be an adequate tool for quality control analysis of therapeutic results after extended skull base surgery.

Background: Chondrosarcoma is a rare differential diagnosis of malignant tumours of the skull base. The prognosis was rated as unfavourable in articles for many years. It has, however, improved considerably in recent years. The objective of this study was to evaluate and current, new optimised treatment strategies., Patients and Methods: We retrospectively analysed the case histories and course of four patients whom we treated for chondrosarcoma of the skull base over the past 5 years at the Freiburg Skull Base Centre., Results: Because of initially mild symptoms, the patients first came for examination at an advanced stage of the tumour. All patients underwent surgery, whereby an R0-resection was barely or only questionably present. Three patients underwent radiation therapy postoperatively. All patients are currently tumour free., Conclusions: Surgical treatment with curative intent is basically the therapy of choice. Due to the usually large size of the tumour and its close relationship to relevant structures, complete resection is, however, not always possible despite advances in surgical procedures. Taking the possibility of modern adjuvant radiotherapeutic procedures into account, an incomplete, function-preserving resection is preferred to a radical and mutilating resection.

Background and Objective: The rare bone disease craniofacial fibrous dysplasia is only treated in cases of visible deformities of the splanchnocranium and neurocranium, compression syndromes, and delocation of nasal and paranasal drainage., Methods and Patients: In a retrospective quality assessment analysis of six patients with craniofacial monostotic fibrous dysplasia, the indications were analysed for situations in which computer-assisted surgery (CAS) might be helpful., Results and Conclusions: CAS serves as an intraoperative basis for the assessment of cosmetic-aesthetic corrections of visible bone deformities of the splanchnocranium and neurocranium, and allows the controlled removal of pathologically affected bone in contralateral symmetry. This seems to be important, especially at the anterior skull base, as deformities of the human face produce strong psychological suffering. Furthermore, CAS allows the configuration of implants for defect reconstruction after focal restorations with bony radical surgery. Implants of various material can be prefabricated from these data, which can then be exactly fitted to cover the defect.

Radiographic imaging of the intratemporal portion of the fallopian canal is important in cases of traumatic facial nerve palsy to visualize the site of involvement. Even if high-resolution computed tomography is used, several images in various planes are necessary to obtain satisfactory diagnostic information. By using a classic axial scan and a wide window (bone algorithm), a 2D reconstruction can be performed "off-line" to visualize the mastoid portion of the fallopian canal. A reconstruction plane 45 degrees to the median-sagittal plane and through the lateral genu of the facial nerve provides the best imaging of the mastoid portion down to the stylomastoid foramen. In cases of temporal bone fractures with facial paralysis, an excellent demonstration of fracture line without further radiation exposure can be obtained in cases considered for surgical decompression.