Showing papers by "Juan C. Fernandez-Miranda published in 2020"

Letter: Precautions for Endoscopic Transnasal Skull Base Surgery During the COVID-19 Pandemic.

Abstract: To the Editor: Since the initial conception of our original letter to the editor,1 the COVID-19 pandemic has unfortunately progressed to infect over 900 000 individuals resulting in over 45 000 deaths,2 and is growing exponentially. Well-documented analysis has traced the travel of infected individuals from Wuhan, China, to New York, Milan, Tehran, and Madrid, cities in countries that in the last week have seen infection levels approach, if not exceed, levels at the initial epicenter in China.3 Indeed, over half of all the world’s documented infections are in Europe (450 000), and the United States is the country most plagued with over 200 000 cases.2 It was with that concern in mind that, when colleagues from China alerted us to the potential spread of COVID-19 to operating room staff, and with increasing reports of significant morbidity and mortality among otolaryngologists in several countries, we were motivated to rapidly share our concerns with the surgical community. The primary purpose of our Letter,1 as the title suggests, was to alert the international readership of Neurosurgery that precautions for endoscopic transnasal skull base surgery during the COVID-19 pandemic were warranted. If our Letter1 potentially prevented one infection, we would feel we have succeeded in our primary purpose. The Wuhan group (Huang et al4), in their recent reply, raised an issue with our report that suggested the likelihood of intraoperative transmission. They confirmed that 14 individuals in their hospital, involved with the care of a COVID-19 patient undergoing transnasal surgery, indeed became infected, but raised the possibility that the infections were from direct contact outside the operating room and not from aerosolization of viral particles in the operating room. We thank them for their response and welcome their report. We acknowledge the difficulties in dealing with the earliest stages of the outbreak in Wuhan, and the controversy and/or challenges regarding its initial management. Despite the absence of direct knowledge by the authors of the Reply Letter,4 we did confirm that the second case of COVID-19 transmission from a patient who underwent emergent transnasal surgery for pituitary apoplexy, as documented in our report,1 did occur at a different hospital in Wuhan, where providers in the operating room became infected despite the use of N95 personal protective equipment (PPE). Interestingly, the anesthesiologist in that case, who wore a powered air-purifying respirator (PAPR), was not infected. As we acknowledged in our Letter,1 anecdotes and personal communications alone cannot provide the definitive evidence we need to make the best decisions regarding PPE in these cases. However, we feel it is unwise to ignore the evidence we do have: that viral load is high within the nasal cavity, that when performing endoscopic surgery we are working within and through that corridor, and that surgical maneuvers can aerosolize mucus particles along with any virus therein. The concerns for potential spread during endonasal surgery in a COVID-19 patient remain high, and our recommendations for preoperative COVID-19 testing and use of PPE are strong. While we agree there is no hard data at this point proving that endonasal surgery in COVID-19 patients can cause widespread infection of operating room personnel, we feel that until further evidence becomes available the recommended precautions should remain in place: COVID-19 testing should be performed when possible, PPE should be employed for all endoscopic cases and for all involved personnel, surgery should be delayed when possible, consideration should be given to transcranial approaches for certain locations where possible, and PAPR use should be encouraged in the rare occurrence of a symptomatic COVID-19positive patient needing emergent endonasal surgery. We look forward with optimism towards the future of endonasal surgery, as COVID-19 testing becomes more rapid and widely available, which should help to inform our understanding of the immune response and immunity of both patients and providers. Similarly, worldwide efforts to control the pandemic, as demonstrated in China and South Korea, among others, will hopefully reduce the incidence of this disease in health care providers and in our potential patients. We applaud the efforts of all physicians and surgeons serving in Wuhan and other corners of the globe, without whom the toll from this virus would have undoubtedly been much greater. We thank the authors for their response to our Letter, as we always welcome open scientific discourse and any information that can be shared globally regarding COVID-19-related cases in order to best protect our hospital teams, our patients, and ourselves.

Results of a prospective multicenter controlled study comparing surgical outcomes of microscopic versus fully endoscopic transsphenoidal surgery for nonfunctioning pituitary adenomas: the Transsphenoidal Extent of Resection (TRANSSPHER) Study

Abstract: OBJECTIVE: Many surgeons have adopted fully endoscopic over microscopic transsphenoidal surgery for nonfunctioning pituitary tumors, although no high-quality evidence demonstrates superior patient outcomes with endoscopic surgery. The goal of this analysis was to compare these techniques in a prospective multicenter controlled study. METHODS: Extent of tumor resection was compared after endoscopic or microscopic transsphenoidal surgery in adults with nonfunctioning adenomas. The primary end point was gross-total tumor resection determined by postoperative MRI. Secondary end points included volumetric extent of tumor resection, pituitary hormone outcomes, and standard quality measures. RESULTS: Seven pituitary centers and 15 surgeons participated in the study. Of the 530 patients screened, 260 were enrolled (82 who underwent microscopic procedures, 177 who underwent endoscopic procedures, and 1 who cancelled surgery) between February 2015 and June 2017. Surgeons who used the microscopic technique were more experienced than the surgeons who used the endoscopic technique in terms of years in practice and number of transsphenoidal surgeries performed (p 0.2). New hormone deficiency was present at 6 months in 28.4% (19/67) of the microscopic surgery patients and 9.7% (14/145) of the endoscopic surgery patients (p < 0.001, OR 3.7, 95% CI 1.7-7.7). Microscopic surgery cases were significantly shorter in duration than endoscopic surgery cases (p < 0.001). CONCLUSIONS: Experienced surgeons who performed microscopic surgery and less experienced surgeons who performed endoscopic surgery achieved similar extents of tumor resection and quality outcomes in patients with nonfunctioning pituitary adenomas. The endoscopic technique may be associated with lower rates of postoperative pituitary gland dysfunction. This study generally supports the transition to endoscopic pituitary surgery when the procedure is performed by proficient surgeons, although both techniques yield overall acceptable surgical outcomes.■ CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: prospective cohort trial; evidence: class III.Clinical trial registration no.: NCT02357498 (clinicaltrials.gov).

Structural white matter connectometry of word production in aphasia: an observational study.

Abstract: While current dual-steam neurocognitive models of language function have coalesced around the view that distinct neuroanatomical networks subserve semantic and phonological processing, respectively, the specific white matter components of these networks remain a matter of debate. To inform this debate, we investigated relationships between structural white matter connectivity and word production in a cross-sectional study of 42 participants with aphasia due to unilateral left hemisphere stroke. Specifically, we reconstructed a local connectome matrix for each participant from diffusion spectrum imaging data and regressed these matrices on indices of semantic and phonological ability derived from their responses to a picture-naming test and a computational model of word production. These connectometry analyses indicated that both dorsally located (arcuate fasciculus) and ventrally located (inferior frontal-occipital, uncinate, and middle longitudinal fasciculi) tracts were associated with semantic ability, while associations with phonological ability were more dorsally situated, including the arcuate and middle longitudinal fasciculi. Associations with limbic pathways including the posterior cingulum bundle and the fornix were also found. All analyses controlled for total lesion volume and all results showing positive associations obtained false discovery rates < 0.05. These results challenge dual-stream accounts that deny a role for the arcuate fasciculus in semantic processing, and for ventral-stream pathways in language production. They also illuminate limbic contributions to both semantic and phonological processing for word production.

Promises and Perils of Artificial Intelligence in Neurosurgery.

Abstract: Artificial intelligence (AI)-facilitated clinical automation is expected to become increasingly prevalent in the near future. AI techniques may permit rapid and detailed analysis of the large quantities of clinical data generated in modern healthcare settings, at a level that is otherwise impossible by humans. Subsequently, AI may enhance clinical practice by pushing the limits of diagnostics, clinical decision making, and prognostication. Moreover, if combined with surgical robotics and other surgical adjuncts such as image guidance, AI may find its way into the operating room and permit more accurate interventions, with fewer errors. Despite the considerable hype surrounding the impending medical AI revolution, little has been written about potential downsides to increasing clinical automation. These may include both direct and indirect consequences. Directly, faulty, inadequately trained, or poorly understood algorithms may produce erroneous results, which may have wide-scale impact. Indirectly, increasing use of automation may exacerbate de-skilling of human physicians due to over-reliance, poor understanding, overconfidence, and lack of necessary vigilance of an automated clinical workflow. Many of these negative phenomena have already been witnessed in other industries that have already undergone, or are undergoing "automation revolutions," namely commercial aviation and the automotive industry. This narrative review explores the potential benefits and consequences of the anticipated medical AI revolution from a neurosurgical perspective.

Pituitary gland recovery following fully endoscopic transsphenoidal surgery for nonfunctioning pituitary adenoma: results of a prospective multicenter study

Abstract: Objective Recovery from preexisting hypopituitarism after transsphenoidal surgery for pituitary adenoma is an important outcome to investigate. Furthermore, pituitary function has not been thoroughly evaluated after fully endoscopic surgery, and benchmark outcomes have not been clearly established. Here, the authors characterize pituitary gland outcomes with a focus on gland recovery following endoscopic transsphenoidal removal of clinically nonfunctioning adenomas. Methods This multicenter prospective study was conducted at 6 US pituitary centers among adult patients with nonfunctioning pituitary macroadenomas who had undergone endoscopic endonasal pituitary surgery. Pituitary gland function was evaluated 6 months after surgery. Results The 177 enrolled patients underwent fully endoscopic transsphenoidal surgery; 169 (95.5%) of them were available for follow-up. Ninety-five (56.2%) of the 169 patients had had a preoperative deficiency in at least one hormone axis, and 20/95 (21.1%) experienced recovery in at least one axis at the 6-month follow-up. Patients with adrenal insufficiency were more likely to recover (10/34 [29.4%]) than were those with hypothyroidism (8/72 [11.1%]) or male hypogonadism (5/50 [10.0%]). At the 6-month follow-up, 14/145 (9.7%) patients had developed at least one new deficiency. The study did not identify any predictors of gland recovery (p ≥ 0.20). Permanent diabetes insipidus was observed in 4/166 (2.4%) patients. Predictors of new gland dysfunction included a larger tumor size (p = 0.009) and Knosp grade 3 and 4 (p = 0.051). Conclusions Fully endoscopic pituitary surgery resulted in improvement of pituitary gland function in a substantial minority of patients. The deficiency from which patients were most likely to recover was adrenal insufficiency. Overall rates of postoperative permanent diabetes insipidus were low. This study provides multicenter benchmark neuroendocrine clinical outcome data for the endoscopic technique.

Evaluation of Surgical Resection Goal and Its Relationship to Extent of Resection and Patient Outcomes in a Multicenter Prospective Study of Patients With Surgically Treated, Nonfunctioning Pituitary Adenomas: A Case Series.

Abstract: BACKGROUND The influence of the surgeon's preoperative goal regarding the extent of tumor resection on patient outcomes has not been carefully studied among patients with nonfunctioning pituitary adenomas. OBJECTIVE To analyze the relationship between surgical tumor removal goal and patient outcomes in a prospective multicenter study. METHODS Centrally adjudicated extent of tumor resection (gross total resection [GTR] and subtotal resection [STR]) data were analyzed using standard univariate and multivariable analyses. RESULTS GTR was accomplished in 148 of 171 (86.5%) patients with planned GTR and 32 of 50 (64.0%) patients with planned STR (P = .001). Sensitivity, specificity, positive predictive value, and negative predictive value of GTR goal were 82.2, 43.9, 86.5, and 36.0%, respectively. Knosp grade 0-2, first surgery, and being an experienced surgeon were associated with surgeons choosing GTR as the goal (P < .01). There was no association between surgical goal and presence of pituitary deficiency at 6 mo (P = .31). Tumor Knosp grade (P = .004) and size (P = .001) were stronger predictors of GTR than was surgical goal (P = .014). The most common site of residual tumor was the cavernous sinus (29 of 41 patients; 70.1%). CONCLUSION This is the first pituitary surgery study to examine surgical goal regarding extent of tumor resection and associated patient outcomes. Surgical goal is a poor predictor of actual tumor resection. A more aggressive surgical goal does not correlate with pituitary gland dysfunction. A better understanding of the ability of surgeons to meet their expectations and of the factors associated with surgical result should improve prognostication and preoperative counseling.

The endoscopic endonasal approach for sinonasal and nasopharyngeal adenoid cystic carcinoma.

Abstract: OBJECTIVE To determine factors affecting outcomes for patients with sinonasal and nasopharyngeal adenoid cystic carcinoma (SNACC) treated using the endoscopic endonasal approach (EEA) with preservation of key structures followed by adjuvant radiotherapy (RT). METHOD Retrospective case series of 30 patients treated at the University of Pittsburgh between 2000 and 2014. Hospital records were reviewed for clinical and pathologic data. Outcome measures included overall survival (OS), disease-free survival (DFS), local recurrence-free survival (LRFS) and distant metastasis-free survival (DMFS) rates. RESULTS The majority of patients had T4a and T4b disease (23.3%, and 63.3%). Microscopically positive margins were present in 21 patients (63.6%). Positive margins were present in nine patients (30.0%). The mean and median follow-up were 3.97 and 3.29 years. Five-year OS, DFS, LRFS, and DMFS were 62.66%, 58.45%, 87.54%, and 65.26%. High-/intermediate-grade tumors had worse DFS (P = .023), and LRFS (P = .026) (HR = 4.837, 95% CI, 1.181-19.812). No factors were associated with significantly worse DMFS. No patient suffered CSF leak, optic nerve, or internal carotid injury. The mean and median length of hospital stay was 4.1 days and 2.0 days (range: 0-32 days). CONCLUSION Organ-preserving EEA with adjuvant RT for low-grade SNACC offers 5-year survival similar to that reported by other studies, which include radical, open skull base surgery. Patients with high-grade disease do poorly and may benefit from novel treatment strategies. For low-grade disease, organ-preserving EEA with RT may be the best option, offering a balance of survival, quality of life, and decreased morbidity for patients with this difficult-to-cure disease. LEVEL OF EVIDENCE 4 Laryngoscope, 130:1414-1421, 2020.

Endoscopic transnasal transmaxillary approach to the upper parapharyngeal space and the skull base

Abstract: Treatment of tumors arising in the upper parapharyngeal space (PPS) or the floor of the middle cranial fossa is challenging. This study aims to present anatomical landmarks for a combined endoscopic transnasal and anterior transmaxillary approach to the upper PPS and the floor of the middle cranial fossa and to further evaluate their clinical application. Dissection of the upper PPS using a combined endoscopic endonasal transpterygoid and anterior transmaxillary approach was performed in six cadaveric heads. Surgical landmarks associated with the approach were defined. The defined approach was applied in patients with tumors involving the upper PPS. The medial pterygoid muscle, tensor veli palatini muscle and levator veli palatini muscle were key landmarks of the approach into the upper PPS. The lateral pterygoid plate, foramen ovale and mandibular nerve were important anatomical landmarks for exposing the parapharyngeal segment of the internal carotid artery through a combined endoscopic transnasal and anterior transmaxillary approach. The combined approach provided a better view of the upper PPS and middle skull base, allowing for effective bimanual techniques and bleeding control. Application of the anterior transmaxillary approach also provided a better view of the inferior limits of the upper PPS and facilitated control of the internal carotid artery. Improving the knowledge of the endoscopic anatomy of the upper PPS allowed us to achieve an optimal approach to tumors arising in the upper PPS. The combined endoscopic transnasal and anterior transmaxillary approach is a minimally invasive alternative approach to the upper PPS.

Full tractography for detecting the position of cranial nerves in preoperative planning for skull base surgery: technical note

Abstract: Objective Diffusion imaging tractography has allowed the in vivo description of brain white matter. One of its applications is preoperative planning for brain tumor resection. Due to a limited spatial and angular resolution, it is difficult for fiber tracking to delineate fiber crossing areas and small-scale structures, in particular brainstem tracts and cranial nerves. New methods are being developed but these involve extensive multistep tractography pipelines including the patient-specific design of multiple regions of interest (ROIs). The authors propose a new practical full tractography method that could be implemented in routine presurgical planning for skull base surgery. Methods A Philips MRI machine provided diffusion-weighted and anatomical sequences for 2 healthy volunteers and 2 skull base tumor patients. Tractography of the full brainstem, the cerebellum, and cranial nerves was performed using the software DSI Studio, generalized-q-sampling reconstruction, orientation distribution function (ODF) of fibers, and a quantitative anisotropy-based generalized deterministic algorithm. No ROI or extensive manual filtering of spurious fibers was used. Tractography rendering was displayed in a tridimensional space with directional color code. This approach was also tested on diffusion data from the Human Connectome Project (HCP) database. Results The brainstem, the cerebellum, and the cisternal segments of most cranial nerves were depicted in all participants. In cases of skull base tumors, the tridimensional rendering permitted the visualization of the whole anatomical environment and cranial nerve displacement, thus helping the surgical strategy. Conclusions As opposed to classical ROI-based methods, this novel full tractography approach could enable routine enhanced surgical planning or brain imaging for skull base tumors.

The Smith-Robinson Approach to the Subaxial Cervical Spine: A Stepwise Microsurgical Technique Using Volumetric Models From Anatomic Dissections.

Abstract: Background The Smith-Robinson1 approach (SRA) is the most widely used route to access the anterior cervical spine. Although several authors have described this approach, there is a lack of the stepwise anatomic description of this operative technique. With the advent of new technologies in neuroanatomy education, such as volumetric models (VMs), the understanding of the spatial relation of the different neurovascular structures can be simplified. Objective To describe the anatomy of the SRA through the creation of VMs of anatomic dissections. Methods A total of 4 postmortem heads and a cervical replica were used to perform and record the SRA approach to the C4-C5 level. The most relevant steps and anatomy of the SRA were recorded using photogrammetry to construct VM. Results The SRA was divided into 6 major steps: positioning, incision of the skin, platysma, and muscle dissection with and without submandibular gland eversion and after microdiscectomy with cage positioning. Anatomic model of the cervical spine and anterior neck multilayer dissection was also integrated to improve the spatial relation of the different structures. Conclusion In this study, we review the different steps of the classic SRA and its variations to different cervical levels. The VMs presented allow clear visualization of the 360-degree anatomy of this approach. This new way of representing surgical anatomy can be valuable resources for education and surgical planning.

Anatomy of the Orbit.

Abstract: The orbit is a paired, transversely oval, and cone-shaped osseous cavity bounded and formed by the anterior and middle cranial base as well as the viscerocranium. Its main contents are the anterior part of the visual system, globe and optic nerve, and the associated neural, vascular, muscular, glandular, and ligamentous structures required for oculomotion, lacrimation, accommodation, and sensation. A complex stream of afferent and efferent information passes through the orbit, which necessitates a direct communication with the anterior and middle cranial fossae, the pterygopalatine and infratemporal fossae, as well as the aerated adjacent frontal, sphenoidal, and maxillary sinuses and the nasal cavity. This article provides a detailed illustration and description of the microsurgical anatomy of the orbit, with a focus on the intrinsically complex spatial relationships around the annular tendon and the superior orbital fissure, the transition from cavernous sinus to the orbital apex. Sparse reference will be made to surgical approaches, their indications or limitations, since they are addressed elsewhere in this special issue. Instead, an attempt has been made to highlight anatomical structures and elucidate concepts most relevant to safe and effective transcranial, transfacial, transorbital, or transnasal surgery of orbital, periorbital, and skull base pathologies.

Nasopharyngeal muscle patch for the management of internal carotid artery injury in endoscopic endonasal surgery.

Abstract: Objective Injury to the internal carotid artery (ICA) is the most critical complication of endoscopic endonasal skull base surgery. Packing with a crushed muscle graft at the injury site has been an effective management technique to control bleeding without ICA sacrifice. Obtaining the muscle graft has typically required access to another surgical site, however. To address this concern, the authors investigated the application of an endonasally harvested longus capitis muscle patch for the management of ICA injury. Methods One colored silicone-injected anatomical specimen was dissected to replicate the surgical access to the nasopharynx and the stepwise dissection of the longus capitis muscle in the nasopharynx. Two representative cases were selected to illustrate the application of the longus capitis muscle patch and the relevance of clinical considerations. Results A suitable muscle graft from the longus capitis muscle could be easily and quickly harvested during endoscopic endonasal skull base surgery. In the illustrative cases, the longus capitis muscle patch was successfully used for secondary prevention of pseudoaneurysm formation following primary bleeding control on the site of ICA injury. Conclusions Nasopharyngeal harvest of a longus capitis muscle graft is a safe and practical method to manage ICA injury during endoscopic endonasal surgery.

Managing complications of endoscopic transsphenoidal surgery in pituitary adenomas.

Abstract: Introduction Over the last two decades there has been a gradual shift from the traditional microscopic approach toward the use of endoscopic endonasal approach for resection of pituitary adenomas. Multiple medical and surgical complications can occur following endoscopic transsphenoidal resection of adenomas. Areas covered We discuss the evolution of the surgical practice from the use of the 'microscope' to the 'endoscope' in the resection of pituitary adenomas. We present a comprehensive review of the medical and surgical complications following surgery with particular emphasis on both the prevention and management of electrolyte disturbance, cerebrospinal fluid leak and the rare but dreaded complication of internal carotid injury (ICA). We also searched the PubMed database to identify relevant literature between 1984 and 2019. Expert opinion Use of endoscope compared with microscope may be associated with better preservation of pituitary gland function with similar extent of resection. Overall medical and surgical complications can be safely managed in high volume centers in association with endocrinologists and skull base trained otolaryngologists. Understanding of anatomico-technical nuances and meticulous surgical technique are important toward preventing ICA injury. Ongoing surgical and technical developments coupled with imaging advances will likely lead to better future outcomes for patients with functioning and nonfunctioning adenomas.

Endoscopic Nasopharyngectomy Combined with a Nerve-sparing Transpterygoid Approach.

Abstract: Objectives/hypothesis Surgical management of nasopharyngeal tumors has evolved in the endoscopic era. Lateral exposure remains difficult especially near the petrous internal carotid artery and bony Eustachian tube (ET). Our study examines the need to sacrifice the vidian and greater palatine nerves in order to successfully perform en bloc endoscopic nasopharyngectomy. Methods Four cadaveric specimens (eight sides) were dissected bilaterally using a binarial, extended, endoscopic endonasal approach (EEA). Nasopharyngectomy was completed including an extended transptyergoid approach for resection of the cartilaginous ET at its junction with the bony ET. Dissection was attempted without sacrifice of the vidian or palatine nerves. Results Successful en bloc nasopharyngectomy combined with a nerve-sparing transpterygoid approach was achieved in all specimens with successful preservation of the palatine and vidian nerves. The approach provided exposure of foramen lacerum, the petrous carotid, foramen spinosum, and foramen ovale as well as all segments of the cartilaginous Eustachian tube, Meckel's cave and the parapharyngeal carotid. There was no inadvertent exposure or injury of the internal carotid artery. Conclusion Endoscopic nasopharyngectomy combined with a nerve-sparing transpterygoid approach allows for en bloc resection of the cartilaginous Eustachian tube and nasopharyngeal contents with broad skull base exposure and preservation of the internal carotid artery, vidian and palatine nerves. Level of evidence VI Laryngoscope, 130:2343-2348, 2020.

Seizure Risk following Open and Expanded Endoscopic Endonasal Approaches for Intradural Skull Base Tumors

Abstract: Objectives The incidence of seizures following a craniotomy for tumor removal varies between 15 and 20%. There has been increased use of endoscopic endonasal approaches (EEAs) for a variety of intracranial lesions due to its more direct approach to these pathologies. However, the incidence of postoperative seizures in this population is not well described. Methods This is a single-center, retrospective review of consecutive patients undergoing EEA or open craniotomy for resection of a cranial base tumor between July 2007 and June 2014. Patients were included if they underwent an EEA for an intradural skull base lesion. Positive cases were defined by electroencephalograms and clinical findings. Patients who underwent a craniotomy to remove extra-axial skull base tumors were analyzed in the same fashion. Results Of the 577 patients treated with an EEA for intradural tumors, 4 experienced a postoperative seizure (incidence 0.7%, 95% confidence interval [CI]: 0.002–0.02). Over the same period, 481 patients underwent a craniotomy for a skull base lesion of which 27 (5.3%, 95% CI: 0.03–0.08) experienced a seizure after surgery. The odds ratio for EEA was 0.13 (95% CI: 0.05–0.35). Both populations were different in terms of age, gender, tumor histology, and location. Conclusion This study is the largest series looking at seizure incidence after EEA for intracranial lesions. Seizures are a rare occurrence following uncomplicated endonasal approaches. This must be tempered by selection bias, as there are inherent differences in which patients are treated with either approach that influence the likelihood of seizures.

Anatomical Limits of the Endoscopic Contralateral Transmaxillary Approach to the Petrous Apex and Petroclival Region

Abstract: Objectives This study aimed to establish the anatomical landmarks for performing a contralateral transmaxillary approach (CTM) to the petrous apex (PA) and petroclival region (PCR), and to compare CTM with a purely endoscopic endonasal approach (EEA). Design EEA and CTM to the PA and PCR were performed bilaterally in eight human anatomical specimens. Surgical techniques and anatomical landmarks were described, and EEA was compared with CTM with respect to ability to reach the contralateral internal acoustic canal (IAC). Computed tomographic scans of 25 cadaveric heads were analyzed and the “angle” and “reach” of CTM and EEA were measured. Results Entry to the PA via a medial approach was limited by (1) abducens nerve superiorly, (2) internal carotid artery (ICA) laterally, and (3) petroclival synchondrosis inferiorly (Gardner's triangle). With CTM, it was possible to reach the contralateral IAC bilaterally in all specimens dissected, without dissection of the ipsilateral ICAs, pterygopalatine fossae, and Eustachian tubes. Without CTM, reaching the contralateral IAC was possible only if: (1) angled endoscopes and instruments were employed or (2) the pterygopalatine fossa was dissected with mobilization of the ICA and resection of the Eustachian tube. The average “angle” and “reach” advantages for CTM were 25.6-degree greater angle of approach behind the petrous ICA and 1.4-cm more lateral reach. Conclusion The techniques and anatomical landmarks for CTM to the PA and PCR are described. Compared with a purely EEA, the CTM provides significant “angle” and “reach” advantages for the PA and PCR.

Endoscopic Endonasal Approach for Resection of Suprasellar Hemangioblastoma: Selective Pituitary Sacrifice and Use of Indocyanine Dye: 2-Dimensional Operative Video.

Abstract: Suprasellar hemangioblastomas are rare lesions occurring sporadically or more commonly with von Hippel Lindau disease (VHLD).1,2 A 27-yr-old female presented with amenorrhea, mildly raised prolactin levels and otherwise normal pituitary function, homonymous hemianopia, and mild cognitive decline. Imaging revealed a large suprasellar lesion arising from the infundibulum, causing compression of optic chiasm with edema in the visual pathways. Lesion appeared hypervascular with prominent feeding vessels from the internal carotid arteries bilaterally. To access these vessels derived from the superior hypophyseal arteries and allow early devascularization, endoscopic endonasal approach was performed.3 Stalk preservation was deemed unlikely. After opening of the suprasellar dura, indocyanine dye allowed early identification of the feeding vessels. They were sequentially sacrificed, allowing early devascularization while preserving the normal blood supply to the optic chiasm from the superior hypophyseal arteries. Pituitary gland and stalk were removed with the latter being completely involved by tumor to provide access to the retroclival region and posterior circulation. After opening of the dura underlying the dorsum sella, inferior pole of the tumor was exposed with blood supply identified from the posterior communicating arteries but not the basilar or posterior cerebral arteries. Devascularized lesion was safely removed from the optic apparatus, hypothalamus, and the third ventricle. Histology was consistent with hemangoblastoma (VHLD negative). Patient's cognitive and visual function normalized with a postoperative magnetic resonance imagingdemonstrating complete resection, no ischemic events on diffusion-weighted imaging, and resolution of the edema in the hypothalamus and visual pathways.1 She was started on desmopressin and replacement therapy for pituitary function. The patient consented to the procedure. Patient provided consent for publication.

Endoscopic endonasal superomedial orbitectomy: How far is safe and possible?

Abstract: Objectives During the endoscopic endonasal approach (EEA) to the anterior cranial base, the lateral boundaries are the lamina papyracea (medial orbital walls) bilaterally but further extension in the coronal plane is possible by performing a superomedial orbitectomy. The aims of this study are to describe the technique of the endoscopic endonasal transethmoidal supraorbital approach to the anterior cranial base and to calculate the extension in the coronal plane added with the superomedial orbitectomy. Methods Thirty superomedial orbitectomies via EEA were completed in 15 fresh-frozen heads. After finishing the procedure, a bifrontal craniotomy with removal of both frontal lobes was performed in order to measure the width of the supraorbital EEA in the coronal plane. We divided the anterior cranial base into five zones related to distinct anatomical segments: sinusal zone, post-sinusal zone, anterior ethmoidal, inter-ethmoidal zone, and posterior ethmoidal zone. Measurements of each segment of the anterior cranial base were taken. Results In all specimens, it was possible to perform a superomedial orbitectomy without excessive retraction of the orbital contents. The inter-ethmoidal zone is the segment where the lateral extension was widest. The mean total width in this area was 45.4 mm. The superomedial orbitectomy added a mean of 8 mm on each side to the total anterior skull base exposure. Conclusion The endoscopic endonasal superomedial orbitectomy added important extension in the coronal plane during an EEA to the anterior cranial base. The inter-ethmoidal zone has shown the greatest lateral extension. Level of evidence N/A Laryngoscope, 130:1151-1157, 2020.

Endoscopic Endonasal Surgery for Resection of Giant Craniopharyngioma in a Toddler-Multimodal Presurgical Planning, Surgical Technique, and Management of Complications: 2-Dimensional Operative Video

Abstract: A 2-yr-old patient with a giant craniopharyngioma presented with seizures and panhypopituitarism. The lesion was initially approached at an outside institution with a transfrontal cyst fenestration, but progressive growth occurred later. Multiple management options were considered; we recommended an endoscopic endonasal approach with the goal of maximal safe resection. Virtual reality simulation and 3-dimensional printing were employed to evaluate whether the absence of pneumatization of the sinuses and the overall size of the nasal cavity could preclude effective surgical access. Our lab results suggested the binostril approach was feasible. A wide surgical exposure was performed from planum sphenoidale to clivus and from orbit to orbit. After removing the large calcified tumor portion, we found an accurate plane of dissection between tumor capsule, hypothalami, and visual pathways. By the end of resection, arterial bleeding was encountered secondary to an avulsion of the posterior communicating artery from the posterior cerebral artery. An angled aneurysm clip was placed with a single-shaft applier to secure the site of injury without narrowing the parent artery. Immediate and delayed magnetic resonance imaging and computed tomography angiography studies showed gross total resection, no stroke, and no pseudoaneurysm formation. On postoperative day 9, patient developed neurological decline and pneumocephalus secondary to necrotic nasoseptal flap. Two endonasal repairs with a lateral nasal wall flap were attempted with no success. A temporoparietal fascia flap was then harvested and transposed from the temporal to the pterygopalatine fossa to successfully repair the skull base defect. The patient has made an extraordinary recovery with no neurological sequalae. The patient's parents provided consent for the procedure and use of intraoperative photos and videos for academic purposes. Institutional Review Board approval was not required.

Endoscopic endonasal resection of a large tuberculum sella meningioma

Abstract: Over the past three decades, endoscopic endonasal surgery has unlocked new corridors to treat a wide spectrum of ventral skull base lesions. Tuberculum sella meningiomas represent one of the most ideal pathologies for ventral skull base access. Traditionally, these lesions were approached primarily through various subfrontal and frontal-lateral transcranial approaches that have unfortunately been shown to be associated with worsening visual decline postoperatively. The endoscopic endonasal approach is now being attempted by more surgeons and leverages an infrachiasmatic trajectory that provides direct access to the tuberculum sella where most of the vascular supply for these lesions can be taken early, facilitating more efficient surgical resection and mitigating the risk of optic nerve injury. Here we review a challenging case of a large (∼3 cm) tuberculum sella meningioma, encasing critical vessels off the circle of Willis and resected via an endoscopic endonasal approach. We discuss the technical nuances and relevant surgical anatomy of this approach and highlight important considerations in the safe and successful removal of these meningiomas. We show that certain tumors that appear to encase the supraclinoidal carotid artery can be fully resected via an endonasal approach with precise surgical technique and adequate exposure. Furthermore, this case illustrates the risk of injuring a key perforating vessel from the anterior communicating artery complex, called the subcallosal artery. Injury to this vessel is highly associated with tumors like the one presented here that extend into the suprachiasmatic space between the optic chiasm and the anterior communicating complex. Meticulous surgical dissection is required to preserve this perforating vessel as well as branches from the superior hypophyseal artery. Finally, we review our current closure techniques for these challenging approaches and discuss the use of a lumbar drain for 3 days to lower CSF leak rates.The video can be found here: https://youtu.be/mafyXi5B0MA.

Deep Learning Improves Pre-Surgical White Matter Visualization in Glioma Patients

Abstract: Background Diffusion tensor imaging (DTI) is a commonly utilized pre-surgical tractography technique. Despite widespread use, DTI suffers from several critical limitations. These include an inability to replicate crossing fibers and a low angular-resolution, affecting quality of results. More advanced, non-tensor methods have been devised to address DTI’s shortcomings, but they remain clinically underutilized due to lack of awareness, logistical and cost factors. Objective Nath et al. (2020) described a method of transforming DTI data into non-tensor high-resolution data, suitable for tractography, using a deep learning technique. This study aims to apply this technique to real-life tumor cases. Methods The deep learning model utilizes a residual convolutional neural network architecture to yield a spherical harmonic representation of the diffusion-weighted MR signal. The model was trained using normal subject data. DTI data from clinical cases were utilized for testing: Subject 1 had a right-sided anaplastic oligodendroglioma. Subject 2 had a right-sided glioblastoma. We conducted deterministic fiber tractography on both the DTI data and the post-processed deep learning algorithm datasets. Results Generally, all tracts generated using the deep learning algorithm dataset were qualitatively and quantitatively (in terms of tract volume) superior than those created with DTI data. This was true for both test cases. Conclusions We successfully utilized a deep learning technique to convert standard DTI data into data capable of high-angular resolution tractography. This method dispenses with specialized hardware or dedicated acquisition protocols. It presents an economical and logistically feasible method for increasing access to high definition tractography imaging clinically.

Effect of oxidized cellulose on human respiratory mucosa and submucosa and its implications for endoscopic skull-base approaches.

Abstract: BACKGROUND Regenerated oxidized cellulose (ROC) sheets have gained popularity as an adjunct to a vascularized nasoseptal flap for closure of dural defects after endoscopic endonasal skull-base approaches (EESBS). However, evidence supporting its impact on the healing process is uncertain. This study was performed to evaluate the impact of ROC on the nasal mucosa and assess its effects on tissue pH, structure, and cell viability. METHODS In 5 patients, a 1-cm2 piece of ROC gauze was placed on the surface of the middle turbinate before it was resected as part of a standard EESBS. Mucosa treated with ROC was separated from untreated mucosa and a histologic examination of structural changes in the respiratory epithelium was performed. To assess the effect of ROC on pH, increasing amounts of ROC were added to culture medium. Nasal fibroblasts viability was assessed in the presence of ROC before and after the pH was neutralized. RESULTS Compared with unexposed controls, treated mucosa exhibited a higher incidence of cell necrosis and epithelial cell detachment. When added to Dulbecco's modified Eagle medium, ROC caused a dose-dependent decrease in pH of the medium. Only 1 ± 0.8% of cultured fibroblasts exposed to the ROC-induced acidic medium were alive, whereas 98.25 ± 0.5% of the cells were viable when the pH was neutralized (p < 0.001). CONCLUSION ROC applied in vivo to nasal mucosa induced epithelial necrosis likely by diminishing the medium pH, because pH neutralization prevents its effect. The ultimate effect of this material on the healing process is yet to be determined.

Endoscopic endonasal surgery for giant pediatric craniopharyngioma

Abstract: Pediatric craniopharyngiomas that were once thought to be inoperable or considered only for salvage medical therapy are now being reconsidered for aggressive surgical resection via endoscopic endonasal approaches. Here we review the operative video case of an 11-year-old with a giant complex craniopharyngioma that was resected via an endoscopic endonasal approach. Due to the extent of tumor burden near the basilar apex, a transclival approach was necessary. To accomplish this, a wide sphenoidotomy, posterior ethmoidectomy, and resection of the middle turbinate were necessary to create enough working space for the resection. We also highlight several key innovations in pediatric endoscopic endonasal surgery management and underscore a multidisciplinary approach that allows for the safe and successful treatment of these lesions. Our multidisciplinary team involves an experienced fellowship-trained endoscopic skull base surgeon and otolaryngologist, as well as a pediatric neurosurgeon, pediatric endocrinologist, pediatric anesthesiologist, and pediatric intensivists who play important roles in the preoperative, intraoperative, and postoperative phases of care of the patient. Finally, we discuss critical surgical decision points including pituitary transposition, which has a lot of conceptual appeal when it is anatomically feasible but unfortunately, in our experience, has low functional preservation rates. Initially, we always aim to utilize pituitary transposition for tuberoinfundibular craniopharyngiomas, and once the relationship between the tumor and the stalk is determined, a decision on whether to preserve or sacrifice the stalk and pituitary gland is made. In this particular case, there was a salvageable stalk and the transposition was performed knowing that the chances for functional preservation were low.The video can be found here: https://youtu.be/ClL73FU5QIU.

The Anterior (Endoscopic Endonasal) Approach and Outcomes for Foramen Magnum Tumors

Abstract: Foramen magnum lesions are rare disorders which may present with cranial nerve dysfunction or compression of the upper spinal cord and medulla resulting in the pathognomonic “foramen magnum syndrome.” Treatment of these lesions is difficult given the proximity of the lesions to the lower cranial nerves, cranio-cervical junction, and vasculature. The surgical approach to these lesions is determined by the location of these structures in relation to the lesion. In a select group of patients, the lesion is medial to the cranial nerves and ventral to the neurovascular structures, whereby an endoscopic endonasal approach would be safe and effective. In this chapter, a case of a foramen magnum meningioma will be presented, the surgical approach and relevant anatomy will be described, and the current literature and outcomes will be reviewed.