Perioperative antibiotic prophylaxis in the setting of cochlear implantation: a retrospective analysis of 700 cases.

PURPOSE: Postoperative wound infections after cochlear implantation are rare but sometimes serious and can lead to explantation. Therefore, perioperative antibiotic administration is often recommended. However, in clinical practice, the type and duration of antibiotic prophylaxis varies between different centers. The aim of this study was to investigate the role of perioperative antibiotic prophylaxis in preventing postoperative complications. METHODS: 700 patients who underwent cochlear implantation between 2007 and 2019 were retrospectively evaluated with regard to wound infections within the first 28 postoperative days. These were classified into major and minor complications. Data were analyzed using the IBM statistical program SPSS. RESULTS: In 670 out of 700 patients the type and duration of perioperative antibiotic administration could be reconstructed from the records. Of these 67 patients (10%) received antibiotics as a single shot, 158 patients (23.6%) were treated with antibiotics for a period of 48 h, and 445 patients (66.4%) received prolonged antibiotic therapy for more than 72 h. In total 64 patients (9.5%) showed abnormalities in wound assessment within the first 28 postoperative days after implantation. Major infections (1.6%) were detected in 11 patients. Overall, there was no statistically significant difference in wound infection rates between the group receiving single-shot antibiosis and the group receiving 48 h prophylaxis or antibiotic treatment > 72 h (p = 0.46). CONCLUSION: Patients receiving an antibiotic single shot do not appear to be at significantly increased risk for postoperative wound infections compared with patients with prolonged antibiotic treatment. Continuation of data collection across centers seems reasonable.

[Interdisciplinary surgery to the central skull base-current status]. / Interdisziplinäre Chirurgie der zentralen Schädelbasis ­ aktueller Stand.

BACKGROUND: The skull base is a surgically complex unit and is often only accessible via combined access routes. Newly developed surgical techniques using microsurgical visualization procedures and active instruments ("powered instruments") as well as multiport accesses enable new, less traumatic surgical corridors. This requires close interdisciplinary cooperation between ENT and neurosurgeons. Currently established access routes to the central skull base are systematized based on the authors' own clinical experience, and discussed in relation to the entity and the current study situation. MATERIALS AND METHODS: A retrospective, qualitative, and descriptive evaluation of the surgical reports of patients with pathologies of the central skull base who were jointly treated by neurosurgery and otorhinolaryngologic/head and neck surgery between 2006 and 2019 was performed. RESULTS: The surgical access routes to the central skull base can be categorized as so-called multiport access routes, partly also in combination, as follows: transnasal-transsphenoidal, subfrontal, subtemporal, transzygomatic, transpterygonal, transpetrous, translabyrinthine, and suboccipital. The choice of access route was based on the location and type of pathology, its inflammatory or space-occupying (benign or malignant tumor) nature, and the possibilities of functional preservation and complete removal. CONCLUSION: Due to the complexity of central skull base structures, the different tumor entities, and the required expertise of different medical specialties, surgery of the central skull base remains a challenge and should only be performed at special competence centers certified according to the criteria of the German Society of Skull Base Surgery.

Influence of patient-specific anatomy on medical computed tomography and risk evaluation of minimally invasive surgery at the otobasis.

PURPOSE: With the increasing use of new minimally invasive approaches in temporal bone surgery, the need arises for evaluation of the risk of injury to sensitive anatomical structures. The factors that influence the measurement uncertainty (variation in representation of position and shape of anatomical structures) of imaging are of relevance. We investigate the effect of patients' anatomy on the measurement uncertainty of medical CT. METHODS: Six formalin-fixed temporal bones were used, fiducial markers were bone-implanted, and 20 CT scans of each temporal bone were generated. Surgically threatened anatomical structures of importance were defined. Manual segmentation was performed to create 3D surface models, and different Gaussian filters were applied. Analysis points were established along the border of the superior semicircular canal to determine the deviation between the 3D images of the labyrinth. The standard uncertainty was calculated, and one-way analysis of variance was performed (significance level = 5%) to evaluate the effect of certain factors (patient, side, Gaussian filter) on the measurement uncertainty. RESULTS: The influence of patient-specific anatomy on the measurement uncertainty of medical CT (p = 0.049) was demonstrated for the first time. The applied Gaussian filter (p = 0.622) and the patient's side (p = 0.341) showed no significant effect. CONCLUSION: The applied method and the results of the statistical analysis suggest that the patient's individual anatomical conditions affect the measurement uncertainty of medical CT. Thus, the patient's anatomy must be considered as an important influencing factor during risk evaluation concerning minimally invasive and image-guided surgery.

Minimally invasive, multi-port approach to the lateral skull base: a first in vitro evaluation.

PURPOSE: The aim of the study was to validate a minimally invasive, multi-port approach to the internal auditory canal at the lateral skull base on a cadaver specimen. METHODS: Fiducials and a custom baseplate were fixed on a cadaver skull, and a computed tomography image was acquired. Three trajectories from the mastoid surface to the internal auditory canal were computed with a custom planning tool. A self-developed positioning system with a drill guide was attached to the baseplate. After referencing on a high precision coordinate measuring machine, the drill guide was aligned according to the planned trajectories. Drilling of three trajectories was performed with a medical stainless steel drill bit. RESULTS: The process of planning and drilling three trajectories to the internal auditory canal with the presented workflow and tools was successful. The mean drilling error of the system (Euclidian distance between the planned trajectory and centerline of the actual drilled canal) was [Formula: see text] mm at the entry point and [Formula: see text] mm at the target. The inaccuracy of the drill process itself and its physical limitations were identified as the main contributing factors. CONCLUSION: The presented system allows the planning and drilling of multiple minimally invasive canals at the lateral skull base. Further studies are required to reduce the drilling error and evaluate the clinical application of the system.

[Surgical simulation on the lateral skull base]. / Chirurgische Simulation an der Laterobasis.

Critical neurovascular structures are confined in a small bony space at the lateral skull base. Thus, high quality of surgical training and planning of minimally invasive procedures is crucial. Simulation of lateral skull base procedures can improve motor skills, anatomical orientation, and complication management in a safe environment. Thus, simulation training can be beneficial for skull base surgeons. Minimally invasive interventions at the lateral skull base are under research, and several authors have presented approaches through single or multiple drilled ports. Precise planning and simulation of such interventions is essential because even submillimeter errors can lead to damage to critical anatomical structures. Therefore, high demands have been set for the accuracy of computer-assisted surgery.

Granulomatosis with polyangiitis and multiple bilateral cranial nerve palsies: a diagnostic challenge.

BACKGROUND: Granulomatosis with polyangiitis is characterized by vasculitis of small and medium sized vessels and non-caseating granulomas with head and neck symptoms in 95% of those affected. Cranial nerve palsies are rare; while, chronic rhinosinusitis and ear problems are common. CASE REPORT: We describe the serious course and the diagnostic challenge of a patient with granulomatosis with polyangiitis of bilateral mastoids and the right temporal lobe. Initially, the patient showed metachronous bilateral facial palsy with chronic mastoiditis. Repeated surgeries and rheumatologic examinations did not determine a diagnosis. The patient developed additional cranial nerve palsies. Due to progression into the temporal lobe, we removed the affected parts. After 6 months, the diagnosis was revealed by histology. RESULTS AND CONCLUSION: Granulomatosis with polyangiitis is a diagnostic challenge. Persistent reevaluations were necessary for a final diagnosis and to limit the life-threatening disease. Once diagnosed, therapy began with the standard FAUCI-Scheme.

[Unsuccessful duraplasty technique or persisting/recanalized Sternberg's canal?]. / Frustrane Duraplastiktechnik oder persistierender/rekanalisierter Sternberg Kanal der Keilbeinhöhle?

Spontaneous rhinoliquorrhea with or without meningo-encephaloceles in the region of the sphenoid sinus occurs very infrequently. It is not uncommon that the attempt of transnasal endoscopic duraplasty in this region leads to recurrence of the CSF leak. The existence of a lateral craniopharyngeal canal can be a possible explanation for these failures.Retrospective analysis of 23 patients with rhinoliquorrhea of different pathogenesis in the region of the frontal and central skull base that were treated with transnasal, video-endoscopic surgical procedures in our department between 2006 and 2011.2 of 23 patients with proven rhinoliquorrhea following a transnasal video endoscopic duraplasty procedure showed a recurrence of the CSF leak. The computertomographic analysis with respect to the current literature indicated the presence of a craniopharyngeal canal at the lateral side of the sphenoid sinus. This canal is also known in the literature as Sternberg's canal. In contrast to the other 21 treated cases there were no planar skull base defects of different pathogenesis in these 2 cases, but a ontogenetically bony canal. The canal can reopen spontaneously or due to an external mechanical impact.The closure of this bony canal requires a modified surgical procedure such as sufficient padding of the bony canal and its sealing by a vascularized pedicle flap in contrast to the ordinary planar bony skull base defects.

[Registration strategies for the application of the navigation system Fiagon at the lateral scull base]. / Registrierstrategien für die Anwendung des Navigationssystems FIAGON an der lateralen Schädelbasis.

OBJECTIVE: The aim of this study was to evaluate a new navigation system (Fiagon GmbH) at the lateral skull base. MATERIAL AND METHODS: We performed repeated measurements and registrations on titanium screws, which were attached to specific anatomical locations on 5 temporal bone specimens. The focus of the investigation is to determinate the Target Registration Error and a comparison of different registration methods. RESULTS: Use of the navigation system seems to be practicable at the lateral scull base. For a registration strategy with 3 onesided attached Fiducials the Target Registration Error is 0.8 mm on the surface of the mastoid and in the mastoid cavity. The measurements at the inner ear canal showed a mean deviation of greater than 1.6 mm. In the comparison of different registration methods the best results were found for registration on titanium screws attached on both sides of the head, followed by surface registration at the face including laterobasis followed by registration in the mastoid cavity only. CONCLUSION: The measured values correspond to our clinical expectations and can be used if the existing Target Registration Error is known and respected. An intra-operative imaging may allow the application of titanium screws for navigation (gold standard) within the same general anesthesia during surgery.

[Chondrosarcoma of the larynx. Experience gained in Freiburg since 1999]. / Chondrosarkome des Larynx. Freiburger Erfahrungen seit 1999.

BACKGROUND: Chondrosarcomas are rare tumors of the head and neck. Nevertheless, they display the most common non-epithelial malignancy of the larynx. MATERIALS AND METHODS: Between 1999 and February 2010 we treated six patients with laryngeal chondrosarcoma. The group included two female and four male patients ranging in age from 54 to 82 years. RESULTS: An 82-year-old female patient died 3 months after diagnosis and tracheostomy due to other underlying diseases. An 82-year-old male patient underwent primary radiation therapy. In the other patients, we performed a modified hemilaryngektomy in three cases and a laryngectomy in one. In those four cases, there were no signs of recurrent disease 50, 85, 87 and 95 months after surgery, respectively. There were no local or distant metastases. CONCLUSIONS: Chondrosarcomas of the larynx are slow growing neoplasms. Metastases occur in less than 3% of cases. Complete resection is the therapy of choice. Function-preserving surgical approaches should be favoured.

[Use of a mechatronic robotic camera holding system in head and neck surgery]. / Anwendung eines aktiven Haltearms in der endoskopischen Kopf-Hals-Chirurgie.

BACKGROUND: It has been shown that a third hand is useful for holding the endoscope during endoscopic surgery so that both hands of the surgeon are free for instrumentation. MATERIAL AND METHODS: Experimental tests were performed with the mechatronic robotic camera holding system Soloassist on anatomical specimens in the area of the nose, nasopharynx and larynx. RESULTS: An ergonomic set-up and the practical application are easily possible. The third hand enables a still and clear picture without undesired camera movement and all instruments can be controlled by the surgeon. There would appear to be some room for improvement as the working area is limited due to an additional instrument. The camera holding system shows a very high velocity for head and neck surgery. CONCLUSION: Until the active holder can be used regularly in clinical practice in the field of head and neck surgery, more technical modifications have to be implemented.

[Insertion results for Contour™ and Contour Advance™ electrodes: are there individual learning curves?]. / Insertionsergebnisse von Contour™- und Contour-Advance™-Elektroden: Gibt es individuelle Lernkurven?

The aim of our study was to evaluate results of insertion following cochlear implantation with Contour™ and Contour Advance™ electrode arrays in adult patients and to analyze individual insertion results for three experienced surgeons. We performed a retrospective analysis of postoperative 3D volume tomography results in 223 adult patients. The intracochlear electrode position was evaluated to be in scala tympani, scala vestibuli or with a dislocation from one scala to the other. Surgical methods were analyzed and assigned to the different surgeons. We observed a significant increase for scala tympani insertions from initially 33% to 84% and a reduction in dislocations from scala tympani to scala vestibuli from 71% with the Contour™ electrode to 22% with the Contour Advance™ electrode. Results for the different surgeons varied individually with regard to scala tympani insertion rates and dislocation rates over time. 3D Volume tomography offers an important method for postoperative quality control following cochlear implant surgery. The intracochlear electrode position could be determined in all cases. We were able to identify individual learning curves for insertion results. Controlling the insertion quality serves as a feedback of surgical results and may be helpful for improving surgical quality and thus rehabilitation results.

[Breast cancer metastases in the head and neck region]. / Mammakarzinommetastasen im Kopf-Hals-Bereich.

Breast cancer metastases to the head and neck region are very rare and therefore represent a challenge for the clinician in terms of diagnosis and therapy. Recent advances in breast cancer treatment have achieved longer median survival times in affected patients. However, at the same time, the risk of a clinical manifestation of metastasis increases. Here we present the cases of two breast cancer patients who developed filiae into the petrous portion of the temporal bone and one very rare case of metastasis to the larynx. Diagnosis, therapy and distinctive features of metastasis to the head and neck region are discussed.Secondary to long-term endocrine hormone therapy, a reduction in estrogen receptor expression occurred in all three cases. We believe that the loss of steroid receptor expression contributed to tumor resistance to endocrine therapy. Moreover, this receptor loss hindered the pathologist from confirming the diagnosis of metastases at very unusual sites.

[Modification of the retrolabyrinthine approach with hearing preservation in CPA tumors]. / Modifizierter retrolabyrinthärer Zugangsweg bei Kleinhirnbrückenwinkeltumoren zum Hörerhalt.

BACKGROUND: In an anatomical study including a CT scan of the cadaver sections by means of a virtual model analysis the option of a modified retrolabyrinthine passage to the cerebellopontine angle (CPA) preserving the Saccus endolymphaticus and the upper petrosus sinus was analysed. METHODS: Due to the individual anatomical variations of the petrosus bone the results showed several limitations with regard to the retrolabyrintine passage to the CPA. The smallest distance between the dura of the posterior fossa and the posterior semicircular canal measured in a high resolution CT was of particular importance as to how much room was available for the surgical manipulation in the retrolabyrinthine space. As the back side angle to the petrosus bone is much flatter in a translabyrinthine approach than in a retrosigmoidal approach the internal auditory canal needed to be controlled by using a 30 degree endoscope. RESULTS: In five patients the translabyrinthine approach was modified by temporarily preserving the labyrinth in an effort to remove the CPA tumors. Based on our clinical experience and on the findings of the anatomical and radiological studies we eventually removed the CPA tumors type B2 or C3 in three patients preserving hearing by using a modified retrolabyrinthine approach.

[Significance of emissary veins in surgical treatment of temporal paragangliomas]. / Stellenwert emissarischer Venen bei der operativen Therapie temporaler Paragangliome.

With the surgical removal of temporal paraganglioma, possible changes of the cerebral blood pathways of the Circle of Willis should be considered. If the cerebral blood drains dominates unilaterally and the pathway of drainage over the Bulbus venae jugularis is inadequate due to vessel malformation or variations or by intraluminal tumor growth, as for instance of temporal paragangliomas, collateral emissary vessels can take over this function by an extraordinary large lumen extension. Ignorance of such a characteristic venous drainage can lead to hemorrhagic apoplexia when such originally redundant veins are sacrificed. A presurgical angiography is, therefore, indicated. In case of vessel malformations or variations the use of computer-assisted surgery could be helpful to preserve such native emissary veins at the bony skull base, such as the condylar emissary vein in the case of a transcondylar infralabyrinthine approach.

[Update on computer- and mechatronic-assisted head and neck surgery in Germany]. / Update in der navigiert kontrollierten und mechatronisch assistierten Kopf-Hals-Chirurgie in Deutschland.

A consequence of the ongoing advances in medical navigation is the development of so-called mechatronic assistant systems. Up to now, medical navigation had been used only for additional intrasurgical orientation. But improvements in accuracy in imaging and medical navigation can exceed the surgeon's possible manual accuracy of surgical manipulation. In such cases, mechatronic assistant systems can supplement certain surgical procedures in order to obtain the required precision, such as for positioning of implants. The development and possible use of such mechatronic assistant systems in the head and neck, as well as improvements in the accuracy of medical navigation, are the focus of several working groups. For coordinating and adapting the various research projects, different research groups were called to present their current projects and results in the context of ASKRA (working group for skull-base and craniofacial surgery of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery) workshops at the German Society for Computer- and Robot-Assisted Surgery (CURAC) convention on 14 October 2006 in Hanover. Different projects were presented, with topics including navigated controlled assistant systems for the frontal and lateral skull base, possibilities for sonographic-induced bone measurement, and requirements for high-precision surgery of the skull base.

[Primary B-cell non-Hodgkin lymphoma of the internal auditory canal: case report and literature review]. / Primäres B-Zell-Non-Hodgkin-Lymphom des inneren Gehörgangs: Fallbericht und Literaturübersicht.

A primary non-Hodgkin lymphoma (NHL) of the internal auditory canal or the cerebellopontine angle is an absolute rarity, even among the unusual lesions encountered there. Schwannomas or meningiomas account for approximately 90-95% of the tumors of the cerebellopontine angle and the internal auditory canal. Atypical symptoms, such as facial nerve palsy or rapid progression, require differential diagnostics to identify less frequent entities. However, clinical symptoms or the image morphology cannot confirm the diagnosis of a lymphoma. If a malignant process is suspected during surgical exploration, an immediate intraoperative biopsy can give important clues for appropriate treatment. The course, diagnostics, and therapy of a rare case of primary B-cell NHL of the internal auditory canal are reported here.

[Navigated "targeted surgery" for skull base malignomas: additional space for surgical manipulation by neoadjuvant tumor downsizing]. / Navigationsunterstützte tumorfokussierte Chirurgie bei Schädelbasismalignomen : Zusätzlicher chirurgischer Manipulationsraum durch neoadjuvante Tumorverkleinerung.

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.

[Craniofacial fibrous dysplasia: scan policy or surgery?]. / Kraniofaziale Fibröse Dysplasie: Observieren oder Operieren?

BACKGROUND: The aetiologic correlations of fibrous dysplasia (FD) are more and more decoded by molecular biology, improved imaging procedures, and the use of computer assisted surgery--thus a review of present diagnostics and therapy methods is evaluated. METHOD: The valid methods of diagnostic and therapy procedures of craniofacial FD were retrospectively analysed in a collective of 9 patients in consideration of literature. The criteria of the decision for diagnosis and surgical procedures were evaluated. RESULTS: According to the literature, diagnosis was ascertained with modern CT and MRI scans. Bone scintigraphy was only used additionally in particular questions. In case of unclear radiological findings histomorphological procedures were used complementarily to distinguish FD from other bone tumors. The aim of surgical intervention was to reduce pain, to restore the function in compression symptoms, to recover original ostia, or to restore the natural geometry of the face. CONCLUSIONS: Current imaging procedures allow differential diagnosis from other benign bone tumors but also from malignancies. The therapy of FD is conservative (wait and scan) or operative in dependence on the localisation, the extension and the clinical manifestations of the disease. In the future molecular biological methods could function as supporting instrument for diagnosis if histomorphological results are not meaningful.