Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Endoscopic Endonasal Approach to the Sellar and Parasellar Regions

Introduction Surgery of the sellar and parasellar regions can be challenging due to the complexity of neurovascular relationships. The main goal of this study is to develop an educational resource to help trainees understand the pertinent anatomy and procedural steps of the endoscopic endonasal approaches (EEAs) to the sellar and parasellar regions. Methods Ten formalin-fixed latex-injected specimens were dissected. Endoscopic endonasal transsphenoidal transsellar, transtuberculum-transplanum, and transcavernous approaches were performed by a neurosurgery trainee, under supervision from the senior authors and a PhD in anatomy with advanced neuroanatomy experience. Dissections were supplemented with representative case applications. Results Endoscopic endonasal transsphenoidal approaches afford excellent direct access to sellar and parasellar regions. After a wide sphenoidotomy, a limited sellar osteotomy opens the space to sellar region and medial portion of the cavernous sinus. To reach the suprasellar space (infrachiasmatic and suprachiasmatic corridors), a transplanum-prechiasmatic sulcus-transtuberculum adjunct is needed. The transcavernous approach gains access to the contents of the cavernous sinus and both medial (posterior clinoid and interpeduncular cistern) and lateral structures of the retrosellar region. Conclusion The anatomical understanding and technical skills required to confidently remove skull base lesions with EEAs are traditionally gained after years of specialized training. We comprehensively describe EEAs to sellar and parasellar regions for trainees to build knowledge and improve familiarity with these approaches and facilitate comprehension and learning in both the surgical anatomy laboratory and the operating room

Thalamic deep brain stimulation modulates cycles of seizure risk in epilepsy

Chronic brain recordings suggest that seizure risk is not uniform, but rather varies systematically relative to daily (circadian) and multiday (multidien) cycles. Here, one human and seven dogs with naturally occurring epilepsy had continuous intracranial EEG (median 298 days) using novel implantable sensing and stimulation devices. Two pet dogs and the human subject received concurrent thalamic deep brain stimulation (DBS) over multiple months. All subjects had circadian and multiday cycles in the rate of interictal epileptiform spikes (IES). There was seizure phase locking to circadian and multiday IES cycles in five and seven out of eight subjects, respectively. Thalamic DBS modified circadian (all 3 subjects) and multiday (analysis limited to the human participant) IES cycles. DBS modified seizure clustering and circadian phase locking in the human subject. Multiscale cycles in brain excitability and seizure risk are features of human and canine epilepsy and are modifiable by thalamic DBS

Medullary Venous Hypertension Secondary to a Petrous Apex Dural Arteriovenous Fistula: A Case Report

Background: Dural arteriovenous fistulae (dAVF) are common intracranial vascular lesions typically becoming symptomatic with cortical venous hypertension and possible hemorrhage. Here, we present a case illustration of a petrous apex dAVF with marked medullary venous hypertension and a unique clinical presentation. Methods: Case report. Results: A 72-year-old female, whose clinical progression was significant for altered mental status and progressive weakness, presented with diplopia, right leg paresis, and ataxia. Magnetic resonance imaging revealed edema involving the medulla. On digital subtraction cerebral angiogram, the patient was found to have a petrous apex dAVF, Cognard type IV. Following treatment with Onyx embolization, her symptoms rapidly improved, with complete resolution of diplopia and drastic improvement of her ataxia. Conclusion: The importance of this case is in the presentation and deterioration of the clinical exam, resembling an acute ischemic event. Further, this case illustrates that dAVF may cause venous hypertension with rapid onset of focal neurologic symptoms not exclusive to cortical locations

Endoscopic and Microscopic Transsphenoidal Surgery of Craniopharyngiomas: A Systematic Review of Surgical Outcomes Over Two Decades

Objective Few studies have compared transsphenoidal endoscopic (TE) and transsphenoidal microscopic (TM) techniques for the treatment of craniopharyngiomas. Design We performed a systematic review of published series. The results were stratified in two time periods from 1995 to 2016. Results A total of 48 articles and 1,186 patients met the inclusion criteria. Overall, 60% of endoscopic cases were supradiaphragmatic, and 76% of microsurgical cases were infradiaphragmatic. Mean tumor size was 3 cm and 2.4 cm in the TE and TM series, respectively ( p = 0.008). Total resection rate was similar (66%) between TE and TM. Considering the surgical outcome for different tumor locations, total resection rate was slightly higher in the TE for supradiaphragmatic lesions (59% versus 42.5%; p = 0.26). Recurrence rate was higher in the endoscopic series (21.7% versus 12%). Mortality and the overall complication rates were similar ( p = 0.84). However, hydrocephalus (7.6%) and cognitive dysfunction (15.8%) were more common in TE, and meningitis (6%) and endocrinologic complications were more common in the TM series. In the past 6 years, the rate of cerebrospinal fluid leak in TE was significantly lower (13%) and was comparable between TE and TM. Conclusion Both techniques appear comparable for infradiaphragmatic lesions; however, TE seems to yield better results for supradiaphragmatic tumors. In conclusion, more complex lesions with difficult locations can be effectively treated with endoscopic surgery

Introduction. Techniques in MRI–Negative Cushing disease

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Expanded endonasal endoscopic resection of anterior fossa meningiomas: Report of 13 cases and meta-analysis of the literature

Object: Transnasal endoscopic (TNE) approaches have been proposed for the resection of anterior cranial base meningiomas. The purpose of this article was to evaluate the results of endoscopic resection of anterior cranial fossa meningiomas by reviewing available published data in addition to the authors' experience with 13 cases. Methods: The literature was searched via OVID to identify all available disaggregate data pertaining to anterior fossa meningiomas treated primarily by TNE. In addition, the authors reviewed the records of a personal series of 13 patients who underwent TNE removal of parasellar meningiomas through a pure TNE approach. Results: Meta-analysis from studies included a total of 69 patients with adequate disaggregated data to summarize. Mean age (\uc2\ub1 SD) at surgery was 53.3 \uc2\ub1 13.0 years (range 27-80 years); 78% of the patients were women. Tumor size was skewed toward smaller lesions, with a mean volume of 24.4 \uc2\ub1 2.9 cm3. Intraoperative impressions were of gross-total resection in 76% of cases. The most common complication reported was CSF leakage, occurring in 32% of the cases (22 of 69). The rate of CSF leakage was not affected by size (p = 0.52), location of tumor (p = 0.9), or age (p = 0.56). There was 1 death overall. The mean duration of follow-up was 21 \uc2\ub1 18 months. Conclusions: Transnasal endoscopic resection of anterior cranial base meningiomas is feasible in selected cases. Reported resection rates are adequate, although the follow-up in the reported series is too short (mean 21 months) to make definitive conclusions regarding the long-term effectiveness. Cerebrospinal fluid leakage is a common complication, although it appears not to be associated with additional morbidity except for the need for reoperation. Long-term results are necessary before considering TNE resection as a valid alternative, in selected cases, to the more established transcranial techniques