Intraoperative Neurophysiological Monitoring for Endoscopic Endonasal Approaches to the Skull Base: A Technical Guide.

Intraoperative neurophysiological monitoring during endoscopic, endonasal approaches to the skull base is both feasible and safe. Numerous reports have recently emerged from the literature evaluating the efficacy of different neuromonitoring tests during endonasal procedures, making them relatively well-studied. The authors report on a comprehensive, multimodality approach to monitoring the functional integrity of at risk nervous system structures, including the cerebral cortex, brainstem, cranial nerves, corticospinal tract, corticobulbar tract, and the thalamocortical somatosensory system during endonasal surgery of the skull base. The modalities employed include electroencephalography, somatosensory evoked potentials, free-running and electrically triggered electromyography, transcranial electric motor evoked potentials, and auditory evoked potentials. Methodological considerations as well as benefits and limitations are discussed. The authors argue that, while individual modalities have their limitations, multimodality neuromonitoring provides a real-time, comprehensive assessment of nervous system function and allows for safer, more aggressive management of skull base tumors via the endonasal route

Use of long implants with distal anchorage in the skull base for treatment of extreme maxillary atrophy : the remote bone anchorage concept

The objectives of this study are to present a new concept of the bone anchorage using long implants in remote bone sites and to discuss four cases treated with this method. Our patients were treated with long implants with a distant anchorage in the skull bone. The planning procedure, the construction of the drill guide, and the surgical protocol are described. In the clinical cases described, all four patients were rehabilitated with the remote bone anchorage concept using long implants anchored in the skull base. Patients were followed for 5 - 12 years and the implants remained present and stable in these time periods. The skull base implant is a new concept of bone anchorage using long implants. It can be a solution for complicated clinical situations (often failed bone reconstructions and implant placements) or an alternative for bone grafting and maxillary augmentation procedures. There is effective implant retention in the skull base, an anatomical area that is often overlooked for implant placement

Pneumoventricle of Unknown Origin. A Personal Experience and Literature Review of a Clinical Enigma

Pneumocephalus (PC) is an uncommon and life-threatening neurological condition. Air within the ventricular system of the brain is also known as Pneumoventricle (PV). It requires emergency treatments to prevent catastrophic neurological outcomes. Head injury is the most common cause of PV, but there are other well-recognized etiologies in case there is no clear radiological evidence of skull discontinuity. Although this clinical entity has been well described in Literature, our report presents the unique feature of describing a purely ventricular PC without evidence of skull base or cranial vault fracture. Therefore, this case presentation explores mysterious causes of fistulous connections with the atmosphere that may lead to air trapped in and around the cranial vault. The aim of the present paper is to report a case of post-traumatic PV without radiological signs of skull base or convexity fracture in a 72-years-old man, underlining the diagnostic and clinical features, and review the relevant Literature

Possible Skull Base Erosion After Prolonged Frontal Sinus Stenting

Frontal sinus stenting is widely used with the goal of maintaining nasofrontal duct patency after sinus surgery. The general recommendation is to leave stents in place for 6 months; however, prolonged stenting up to 6 years has been reported with no complication. We present the first reported case of frontal sinus posterior table and skull base erosion following prolonged frontal sinus stenting. A 57-year-old female presented with chronic sinusitis and nasal obstruction. Imaging revealed pansinusitis with retained stents in each frontal sinus that were placed 8 years prior. On the right, there was an area of skull base erosion at the tip of the stent. The patient underwent functional endoscopic sinus surgery with polypectomy. The stents were removed, revealing posterior table erosion on the right side but intact mucosa. Two months after surgery, there were no signs or symptoms of cerebrospinal fluid leak or other complications. Recent literature has suggested that prolonged stenting is safe; however, this case highlights a complication with potentially serious outcomes that can result from prolonged stenting. We recommend stent removal once stable nasofrontal duct patency has been achieved. If prolonged stenting is utilized, patients should be closely monitored and consideration should be given to periodic imaging to evaluate stent position

Management of Noncatastrophic Internal Carotid Artery Injury in Endoscopic Skull Base Surgery.

Arterial injuries are the most feared complication of endoscopic skull base surgery. During resection of the middle fossa component of a large ventral skull base chondrosarcoma, arterial bleeding was encountered near the right internal carotid artery (ICA). Durable hemostasis could not be achieved with packing and the patient was taken for an emergent angiogram that revealed a pseudoaneurysm of the proximal intradural ICA. Given the presence of good collateral flow through the anterior and posterior communicating arteries, the right ICA was sacrificed by coil embolization. The patient was taken back to the operating room for closure then transferred to the intensive care unit and maintained on vasopressors for five days to ensure adequate perfusion. The right ICA was coil embolized and the patient was taken back to the operating room for closure. The patient recovered without complication. Arterial injuries, although serious, are not always catastrophic. Critical steps are immediate recognition of bleeding, vascular imaging, and vessel sacrifice if necessary

Complete response of skull base inverted papilloma to chemotherapy: Case report.

BackgroundInverted papilloma (IP) is the most common benign sinonasal neoplasm. Endoscopic techniques, improved understanding of pathophysiology, and novel surgical approaches have allowed rhinologists to treat IPs more effectively, with surgery being the mainstay of therapy. Frontal sinus IP poses a challenge for surgical therapy due to complex anatomy and potentially difficult surgical access.ObjectivesWe reported a unique case of a massive frontal sinus IP that presented with intracranial and orbital extension, with near resolution after chemotherapy.MethodsA retrospective case review of a patient with a frontal sinus IP treated at a tertiary academic medical center.ResultsA 75-year-old male patient presented with nasal obstruction, purulent nasal discharge, and a growing left supraorbital mass. Endoscopy demonstrated a mass that filled both frontal and ethmoid sinuses, with orbital invasion. There also was substantial erosion of the posterior table, which measured 1.73 × 1.40 cm. A biopsy specimen demonstrated IP with carcinoma in situ. The patient was deemed unresectable on initial evaluation and, subsequently, underwent chemotherapy (carboplatin and paclitaxel). The tumor had a dramatic response to chemotherapy, and the patient elected for definitive surgery to remove any residual disease. During surgery, only a small focus of IP was found along the superior wall of the frontal sinus. No tumor was found elsewhere, including at the site of skull base erosion. The final pathology was IP without carcinoma in situ or dysplasia.ConclusionThis was the first reported case of chemotherapeutic "debulking" of IP, which facilitated surgical resection, despite substantial intracranial and orbital involvement. Although nearly all IPs can be treated surgically, rare cases, such as unresectable tumors, may benefit from systemic chemotherapy

The pursuit of a cholesteatoma by harvey cushing: staged approach to a complex skull base tumor

Objective The evolution of neurosurgical techniques during Harvey Cushing's practice was immense. The authors illustrate this evolution using archived historical records from Harvey Cushing. Setting Historical patient records retained by the Cushing Center at Yale University Department of Neurosurgery. Design The authors present the case of one of Cushing's patients with a cholesteatoma. Results Cushing's surgical treatment of a cholesteatoma extending into the skull base is an example of his meticulous documentation and accelerated surgical techniques. Conclusions This case demonstrates how neurosurgical techniques advanced in the management of complex skull base tumors via a staged approach through the middle and posterior fossae at a time long before the development of modern skull base surgery

Anatomical and Behavioral Aspects of Killing and Feeding by the Least Weasel, Mustela nivalis L.

The least weasel (Mustela nivalis) is a remarkably well adapted predator of mice and other small animals. Each kill is rather stereotyped, in that the weasel grabs the prey by the nape of the neck and bites through the base of the skull and/or throat, using its lithe body to wrap up and hold the prey. The least weasel will kill mice successively until it is too exhausted physically to kill more. Mice are always eaten from the head posteriorly until completely consumed

Stereotactic Radiosurgery Pada Benign Skull Base Tumor

Total removal is difficult to be performed in skull base tumors because its location is surrounded by important structures such as nerves and blood vessels. Therefore, radiotherapy is one of treatment modalities that has been proven efficacy. Simultaneous with the development of imaging technology and advancement of radiobiology, radiosurgery is an emerging therapeutic modality. Radiosurgery is radiotherapy method which delivers high doseirradiation in single fraction. Rational use of stereotactic radiosurgery on benign skull base tumor is from radiobiology point of view; there is no advantage can be achieved from conventional dose fractionated radiotherapy compared with high dose. However, if we want to delivered high dose radiation, we must apply rigid immobilization, target definition using stereotactic navigation and image guidance verification. Radiosurgery can only be delivered in small intracranial lesion