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Background Sinonasal inverted papilloma (SNIP) is histologically benign but locally aggressive, with high recurrence rates and a relevant risk of malignant transformation. Tumor involvement of the nasal root and overlying skin may result in a full-thickness craniofacial defect with direct intracranial–external communication. Reconstruction is particularly challenging after failure of conventional skull base techniques (e.g., titanium mesh and pericranial flaps), which may lead to pneumocephalus, cerebrospinal fluid (CSF) leakage, and infection. Objective To describe a multidisciplinary staged salvage strategy combining bifrontal craniotomy with a vascularized anterolateral thigh (ALT) free flap for definitive reconstruction of complex anterior skull base and nasion defects after failed conventional reconstruction. Methods We report a recurrent SNIP case with failed initial skull base reconstruction. After infection control and resolution of pneumocephalus, an ALT free flap was used. The pedicle was routed transcranially through an enlarged skull base defect to temporal recipient vessels, enabling three-layer reconstruction from dura to skin and restoration of nasal dorsum contour. Results Definitive reconstruction was completed in 7 h. The flap survived without vascular compromise. During the postoperative course and early follow-up, no CSF leak, infection, or recurrent pneumocephalus was observed. Stable intracranial–extracranial separation and satisfactory functional/aesthetic outcomes were achieved. Conclusion Bifrontal re-exploration followed by staged ALT free-flap reconstruction represents a viable salvage option for complex anterior skull base defects after failed primary repair. In our experience, transcranial pedicle routing and a three-layer reconstruction approach can facilitate effective intracranial-extracranial separation.

We show that activation of Wnt/β‐catenin and attenuation of Bmp signals, by combined gain‐ and loss‐of‐function mutations of β‐catenin and Bmpr1a, respectively, results in rapidly growing, aggressive squamous cell carcinomas (SCC) in the salivary glands of mice. Tumours contain transplantable and hyperproliferative tumour propagating cells, which can be enriched by fluorescence activated cell sorting (FACS). Single mutations stimulate stem cells, but tumours are not formed. We show that β‐catenin, CBP and Mll promote self‐renewal and H3K4 tri‐methylation in tumour propagating cells. Blocking β‐catenin–CBP interaction with the small molecule ICG‐001 and small‐interfering RNAs against β‐catenin, CBP or Mll abrogate hyperproliferation and H3K4 tri‐methylation, and induce differentiation of cultured tumour propagating cells into acini‐like structures. ICG‐001 decreases H3K4me3 at promoters of stem cell‐associated genes in vitro and reduces tumour growth in vivo . Remarkably, high Wnt/β‐catenin and low Bmp signalling also characterize human salivary gland SCC and head and neck SCC in general. Our work defines mechanisms by which β‐catenin signals remodel chromatin and control induction and maintenance of tumour propagating cells. Further, it supports new strategies for the therapy of solid tumours. Hyperproliferation of tumour‐propagating cells in squamous cell carcinoma depends on Wnt/β‐catenin signalling, which induces an open chromatin state and expression of self‐renewal genes.

Background Skull base osteomyelitis (SBO) is a severe disease not only because of its rapid progression and its high mortality: diagnosis and treatment are often protracted and in more than 30% of cases no causative pathogen can be detected. SBO is usually preceded by immunodeficiency, which is why opportunistic infections caused by atypical pathogens must also be taken into consideration. In consideration of the different possible entities, an interdisciplinary approach with surgical debridement, pathological sampling, microbiological testing and antimicrobiological therapy is indispensable. Case presentation We report on a 58-year-old female patient who presented to our clinic for the first time in 2014 with a bilateral skull base osteomyelitis. The patient had a history of several comorbidities, including hypogammaglobulinemia following the successful treatment of a relapsed B-CLL. Different surgical treatments had already been attempted at the time of initial presentation. Several rheumatological, orthopedic, haemato-oncological and divergent microbiological differential diagnoses could be ruled out. Despite various interdisciplinary treatment attempts (including surgery, antibiotic therapies and hyperbaric oxygen therapy) the progress led to a palsy of the caudal cranial nerve group in 2022. With all preceded microbiological sampling being negative, we initiated species specific PCRs covering atypical organisms. An atypical infection of Mycoplasma pneumoniae was detected. After starting antibiotic therapy with azithromycin and doxycycline the progress could be halted and the palsies were regredient. The following MRI scans confirmed a decline in findings. Conclusions To the authors' knowledge, this case report is the first description of SBO as an extrapulmonary M. pneumoniae infection. It shows the diagnostic and therapeutic complexity of a multifaceted clinical picture in which immunological, microbial and ENT-surgical diagnostic and therapeutic concepts must be regularly coordinated. Against the background of the high proportion of missing pathogens up to 30%, interdisciplinary cooperation within the framework of the ABS concept is emphasized. Structured and interdisciplinary diagnostics by a skull base center specializing in this field was ultimately decisive for treatment in this case.

PurposeAccurate estimation of the position and orientation (pose) of surgical instruments is crucial for delicate minimally invasive temporal bone surgery. Current techniques lack in accuracy and/or line-of-sight constraints (conventional tracking systems) or expose the patient to prohibitive ionizing radiation (intra-operative CT). A possible solution is to capture the instrument with a c-arm at irregular intervals and recover the pose from the image.Methodsi3PosNet infers the position and orientation of instruments from images using a pose estimation network. Said framework considers localized patches and outputs pseudo-landmarks. The pose is reconstructed from pseudo-landmarks by geometric considerations.ResultsWe show i3PosNet reaches errors <0.05 mm. It outperforms conventional image registration-based approaches reducing average and maximum errors by at least two thirds. i3PosNet trained on synthetic images generalizes to real X-rays without any further adaptation.ConclusionThe translation of deep learning-based methods to surgical applications is difficult, because large representative datasets for training and testing are not available. This work empirically shows sub-millimeter pose estimation trained solely based on synthetic training data.

PurposeRobot-assisted surgery at the temporal bone utilizing a flexible drilling unit would allow safer access to clinical targets such as the cochlea or the internal auditory canal by navigating along nonlinear trajectories. One key sub-step for clinical realization of such a procedure is automated preoperative surgical planning that incorporates both segmentation of risk structures and optimized trajectory planning.MethodsWe automatically segment risk structures using 3D U-Nets with probabilistic active shape models. For nonlinear trajectory planning, we adapt bidirectional rapidly exploring random trees on Bézier Splines followed by sequential convex optimization. Functional evaluation, assessing segmentation quality based on the subsequent trajectory planning step, shows the suitability of our novel segmentation approach for this two-step preoperative pipeline.ResultsBased on 24 data sets of the temporal bone, we perform a functional evaluation of preoperative surgical planning. Our experiments show that the automated segmentation provides safe and coherent surface models that can be used in collision detection during motion planning. The source code of the algorithms will be made publicly available.ConclusionOptimized trajectory planning based on shape regularized segmentation leads to safe access canals for temporal bone surgery. Functional evaluation shows the promising results for both 3D U-Net and Bézier Spline trajectories.

Introduction and objectives Head and neck cancer remains a major global health challenge, with radiotherapy representing a central component of curative and palliative treatment. Despite advances in precision techniques, high-dose irradiation unavoidably affects adjacent oral structures, leading to a broad spectrum of side effects. These include dental caries, periodontitis, xerostomia, mucositis, candidiasis, trismus, dysphagia, and osteoradionecrosis—each with potential for chronic morbidity and diminished quality of life. This scoping review aims to summarize current evidence on oral side effects associated with head and neck radiotherapy, raise interdisciplinary awareness and propose a dental care model ensuring individualized therapies while focusing on prevention. Data Radiation-induced oral effects are common, multifactorial, and often long-lasting. Caries and periodontitis are largely driven by hyposalivation and mucosal compromise, while trismus reflects dose-dependent impairment of the masticatory apparatus. Osteoradionecrosis, though less frequent, carries severe clinical consequences. Sources A systematic literature search was conducted using PubMed for articles published between 1999 and November 2025. The search strategy combined the terms “head and neck cancer”, “radiotherapy” with the side effects mentioned above. Study selection Studies were considered eligible if they examined oral side effects resulting from radiotherapy in patients with head and neck cancer, in total, 151 studies were included into the review. Results We describe the epidemiology, underlying mechanisms, and clinical manifestations of common sequelae and provide a structured overview of preventive and therapeutic strategies. Clinical significance The understanding, early identification and management of radiation-induced oral complications are essential to preserve function, maintain quality of life, and improve long-term outcomes for head and neck cancer patients.

Lasers have been proven to be precise tools for bone ablation. Applying no mechanical stress to the patient, they are potentially very suitable for microsurgery on fragile structures such as the inner ear. However, it remains challenging to control the laser-bone ablation without injuring embedded soft tissue. In this work, we demonstrate a closed-loop control of a short-pulsed CO2 laser to perform laser cochleostomy under the monitoring of an optical coherence tomography (OCT) system. A foresighted detection of the bone-endosteum-perilymph boundary several hundred micrometers before its exposure has been realized. Position and duration of the laser pulses are planned based on the residual bone thickness distribution. OCT itself is also used as a highly accurate tracking system for motion compensation between the target area and the optics. During ex vivo experimental evaluation on fresh porcine cochleae, the ablation process terminated automatically when the thickness of the residual tissue layer uniformly reached a predefined value. The shape of the resulting channel bottom converged to the natural curvature of the endosteal layer without injuring the critical structure. Preliminary measurements in OCT scans indicated that the mean absolute accuracy of the shape approximation was only around 20 μm.

Objective. Minimally invasive procedures minimize iatrogenic tissue damage and lead to a lower complication rate and high patient satisfaction. To date only experimental minimally invasive single-port approaches to the lateral skull base have been attempted. The aim of this study was to verify the feasibility of a minimally invasive multiport approach for advanced manipulation capability and visual control and develop a software tool for preoperative planning. Methods. Anatomical 3D models were extracted from twenty regular temporal bone CT scans. Collision-free trajectories, targeting the internal auditory canal, round window, and petrous apex, were simulated with a specially designed planning software tool. A set of three collision-free trajectories was selected by skull base surgeons concerning the maximization of the distance to critical structures and the angles between the trajectories. Results. A set of three collision-free trajectories could be successfully simulated to the three targets in each temporal bone model without violating critical anatomical structures. Conclusion. A minimally invasive multiport approach to the lateral skull base is feasible. The developed software is the first step for preoperative planning. Further studies will focus on cadaveric and clinical translation.

Head and neck squamous cell carcinomas (HNSCCs) form a heterogeneous tumor entity located throughout the oral cavity, pharynx and larynx that is caused predominantly by chemically or virally induced carcinogenesis. Heterozygous germline mutations in cancer susceptibility genes might also lead to increased incidence of HNSCCs. As DNA stability is typically impaired in HNSCC cells and genes of the Fanconi anemia/BRCA DNA repair pathway can be mutated or down-regulated in HNSCCs, we investigated here whether germline mutations occur in the X-chromosomal FANCB as candidate gene. Germline DNA of 85 consecutive HNSCC patients was sequenced. Missense alterations in FANCB were functionally tested in reference cells. Four single nucleotide polymorphisms were identified, three of which were located in untranslated regions of FANCB (rs2188383, rs2375729, rs2905223) and predicted to be associated with normal function. One missense alteration, c.1004G>A resulting in p.G335E (rs41309679), in exon 4 was detected in five men in homozygous and in five women in heterozygous state. Four in silico prediction programs uniformally predicted p.G335E to be associated with loss-of-function of the protein. To clarify these predictions, we expressed the FANCB p.G335E protein in primary human FANCB deficient fibroblasts. Cell cycle analysis of these fibroblasts established that the FANCB p.G335E was functionally indistinguishable from the wildtype FANCB protein. Thus, functional studies in genetically defined cells showed that the p.G335E germline alteration in FANCB is not associated with impaired function.

Dermoid cysts (DCs) are rare benign, epithelial-lined lesions. Up to 7% of them are found in the head and neck region and 80% of those predominantly occur in the orbit, in the nose, and in the floor of the mouth. The average age of presentation is around the age of six. Dermoid cysts located in the parotid gland have only been published in 19 cases so far. Interestingly, the mean age of occurrence in the parotid gland was much higher (31 years). We report on a four-year-old girl being the youngest patient who had ever been diagnosed with this disease.