Avoiding vascular complications in insular glioma surgery - A microsurgical anatomy study and critical reflections regarding intraoperative findings.

Introduction: Vascular lesions in insular glioma surgery can severely impact patients' quality of life. This study aims to present the results of our dissections and authors' reflections on the insular vascular anatomy. Matherials and Methods: The insular vascularization was examined using ×3 to ×40 magnification in 20 cadaveric cerebral hemispheres in which the arteries and veins had been perfused with colored silicone. Results: In insular gliomas, this individualization of the anatomical structures is rarely possible, as the gyri are swollen by the tumor and lose their individuality. In the transsylvian approaches, the anatomical parameters for delimiting the insula in tumors are best provided by the superior and inferior circular sulci. The branches of the MCA are easily identified in the transcortical approach, but only at the end of the surgery after the tumor is resected.). One of the factors under-discussed in the literature is the involvement of the lenticulostriate arteries by the medial part of the tumor. In our experience of 52 patients (article submitted to publishing), LSTa were founded to be involved by the tumor in 13 cases. In 39 patients, there was no involvement of the LSTa, which allowed a more aggressive resection. Early preoperative identification of the anterior perforated substance on the MRI and its proximity to the tumor may help determine the route of the LSTa over the medial tumor boundaries. Discussion: Our reflections introduced our imaging and anatomical concept regarding LSTa in insular glioma surgery. Accurate identification of origin, route, and distribution of the LSTa is pivotal to surgical success, especially in the lateral group. The anatomical knowledge of their path directly impacts the extent of tumor resection and functional preservation. Conclusion: Knowledge of microsurgical anatomy, brain mapping, and surgical experience counts a lot in this type of surgery, creating a reasonable procedure flowchart to be taken intraoperatively.

The Learning Curve in Skull Base Surgery Part 1­ From Historical-Philosophical Concepts to Microsurgical Lab Training

The learning curve reflects surgeons' experience in managing several patients with the same disease. In skull base surgery, the professional's place on the curve could be related to the number of times the same procedure was performed. Where does curve begin? What amount of training is necessary prior to its application in surgical settings? What were the results of the first few skull base tumor surgeries performed by a surgeon who goes on to produce excellent results, and how is reflected in the start of their learning curve? The only way for neurosurgeons to improve their results from the start is with prior training in the microsurgery laboratory. This learning technique is essential to maximize the chance of success of a neurosurgical procedures, minimizing the morbidity rate to which patients are subjected by less experienced neurosurgeons. This article is divided in two parts, and its purpose is to show how training in the microsurgical laboratory fits into the construction of knowledge about skull base surgery, based on authors' experience and reflections. This first part discusses the technical, psychological, and philosophical aspects of medical knowledge, primarily addressing those training in skull base surgery, the principles of some selected philosophical currents, and their influence on the development of current medical knowledge.

The Learning Curve in Skullbase Surgery Part 2­From the Microsurgical Lab Training to the Operative Room / A Curva de Aprendizado em Cirurgia de Base do Crânio - Do laboratório de microcirurgia à sala cirúrgica

In this second part, the authors review and suggest a methodology for studies in skull base surgery and training inmicrosurgical laboratory, based on their experiences and reflections. Not only are the foundations for the acquisition of microsurgical skills presented, but also what is needed to be an effective skullbase surgeon with good results. The present article reflects in particular the philosophy of professor Evandro de Oliveira and also serves to present to the neurosurgical community a new state-of-the-art laboratory for hands-on courses in Brazil, at the Faculdade Evangélica Mackenzie do Paraná.

Nesta segunda parte, os autores revisam e sugerem uma metodologia para o estudo em cirurgia de base de crânio e treinamento em laboratório de microcirurgia baseado em suas experiencias e reflexões. Não apenas os fundamentos para a aquisição de habilidades microcirúrgicas estão presentes, como também, o que é necessário para ser um eficiente cirurgião de base de crânio com bons resultados. Este artigo reflete, em particular, a filosofia do Professor Evandro de Oliveira, além de servir para apresentar a comunidade neurocirúrgica o novo "estado da arte" em laboratórios de cursos "hands-on" no Brasil, na Faculdade Evangélica Mackenzie do Paraná.

A Novel Technique for Transpalatal Hypophysectomy.

Objective A novel technique is described for transpalatal hypophysectomy as an option for sellar region surgery using a microscope and/or endoscope. Technique A straight submucosal tunnel (approximately 20 mm in diameter; 40-50 mm long-half the length required by conventional transsphenoidal hypophysectomy) is dissected in favorable alignment with the main tumor axis, providing a direct view that allows the surgeon to operate on large suprasellar tumors, even in cases of extra-axial expansion. Results In a 25-year period, over 50 patients benefited from this surgery. Macroadenomas devoid of extra-axial expansions were totally excised (76.5%), otherwise, partially (23.5%). Forty-nine patients (98%) were extubated soon after surgery. Mean surgery duration was 3 hour 32 minute, with 2 days 6 hour before free feeding was restored. Postoperative hospitalization under neurosurgical care averaged 6 days 6 hour. Currently, patients undergoing the procedure do not require nasal tampons and can eat soft foods soon after recovery from anesthesia. Although two patients (3.9%) presented with oronasal fistulae postoperatively, no episodes of severe hemorrhage occurred during surgery and there were no cases of liquoric fistulae, visual impairment, panhypopituitarism, or severe syndrome of inappropriate antidiuretic hormone secretion. Conclusion The new surgical approach is safe, effective, and well accepted by patients, who reported low levels of discomfort. Postsurgical complications or sequela are currently rare, but further operations should be performed using more appropriate materials, instruments, and equipment to allow comparisons with other techniques.

Lateral nasal wall flap for endoscopic reconstruction of the skull base: anatomical study and clinical series.

BACKGROUND: The lateral nasal wall (LNW) flap provides vascularized endonasal reconstruction primarily in revision surgery. Although the harvesting technique and reconstructive surface have been reported, the arterial supply to the LNW flap and its clinical implications is not well defined. This study presents anatomical dissections to clarify the vascular supply to this flap, and the associated clinical outcomes from this reconstructive technique. METHODS: The course and branching pattern of the sphenopalatine artery (SPA) to the LNW were studied in 6 vascular latex-injected heads (11 LNW flaps total). Patients undergoing an LNW flap since 2008 were identified and the underlying pathology, indication, flap viability, and clinical outcomes were retrospectively analyzed. RESULTS: The inferior turbinate artery arises from the LNW artery and divides into 2 branches at the most posterior aspect of the inferior turbinate bone. A smaller-caliber superficial branch travels anteriorly and branches to the LNW. A larger dominant branch travels into the inferior meatus and tangentially supplies the nasal floor. Twenty-four patients with sellar or posterior cranial fossa (PCF) defects were reconstructed with an LNW flap. Postoperative contrast enhancement of the LWN flap was identified in 95.5% of cases. Postoperative cerebrospinal fluid (CSF) leaks were identified in 6 cases. CONCLUSION: Blood supply to the nasal floor by the dominant inferior meatus branch is more robust than the supply to the anterior LNW by the superficial arterial branch. The LNW flap is the preferred vascularized reconstructive option to the PCF and sella in the absence of a nasoseptal flap (NSF).

Incidence, risk factors, and outcomes of endoscopic sinus surgery after endoscopic skull-base surgery.

BACKGROUND: Patients undergoing endoscopic resection of neoplasms with both sinonasal and skull base involvement can develop chronic rhinosinusitis (CRS) after treatment and may occasionally benefit from additional endoscopic sinus surgery (ESS). We investigate risk factors and outcomes associated with revision ESS (rESS) after endoscopic skull-base surgery (SBS) for neoplasms with combined sinonasal and skull base involvement. METHODS: A retrospective review of patients with neoplasms with both sinonasal and skull base involvement who underwent endoscopic resection at a single tertiary care academic institution from 2004 through 2017 was performed. Eighty-three patients were included. Main outcome measures included incidence and timing of revision surgery, Lund-Mackay (LM) scores, and 22-item Sino-Nasal Outcome Test (SNOT-22) scores. RESULTS: rESS was performed in 21 (25%) cases, 15 (18%) of which were due to CRS. Time between initial resection and rESS was an average of 42 months (range, 6 to 142 months). Pre-SBS and post-SBS LM scores were not significantly different (5.0 vs 4.7, p = 0.640), although pre-SBS and post-SBS SNOT-22 scores showed significant improvement (32.6 vs 24.5, p = 0.030). Malignant pathology correlated with need for rESS (odds ratio [OR] 5.07, p = 0.04), as well as treatment including chemotherapy (OR 5.10, p = 0.003) and radiation (OR 4.15, p = 0.013). CONCLUSION: A significant proportion of patients develop clinically significant sinusitis after endoscopic SBS for neoplasms with combined sinonasal and skull base involvement and may benefit from rESS. Intervention occurred, on average, 3.5 years after initial tumor resection. Malignant pathology, radiation therapy, and chemotherapy correlate with need for rESS.

Inverted papilloma is associated with greater radiographic inflammatory disease than other sinonasal malignancy.

BACKGROUND: The pathogenesis of inverted papilloma (IP) has not been fully elucidated. However, chronic paranasal sinus inflammation has been anecdotally observed in sites distant from tumor obstruction in IP patients, suggesting an association between inflammation and IP tumorigenesis. This study assesses the association between sinonasal inflammation found in IP and compares this to the level of inflammation observed in other sinonasal tumors. METHODS: A retrospective chart review was performed identifying patients with unilateral IP. Pertinent clinical data was obtained and comparative analysis of preoperative computed tomography (CT) imaging and histopathology was performed. A sample of unilateral, sinonasal, non-IP and non-squamous cell tumors was used as the control. The Lund-Mackay scoring system was used to assess radiologic sinonasal inflammation both ipsilateral and contralateral to the tumor. RESULTS: Seventy-one patients were included; 58.9% of patients with IP had evidence of contralateral sinusitis at the time of presentation. In the control group, 26.7% had evidence of contralateral inflammation. When comparing contralateral sinus inflammation between the 2 study groups, the IP patients had significantly higher Lund-Mackay scores than the control group (1.9 vs 0.26, p < 0.001). When comparing ipsilateral sinus inflammation, no significant difference was found in Lund-Mackay scores (5.44 vs 4.00, p < 0.184). CONCLUSION: In this study, unilateral IPs were associated with a higher level of contralateral sinonasal inflammation when compared to control. This suggests that IP may be associated with inflammation that is independent of obstruction by the tumor. Further studies are needed to better understand the temporal relationship between chronic inflammation and tumorigenesis.

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

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.

Economic implications of localization strategies for cerebrospinal fluid rhinorrhea.

BACKGROUND: The direct costs associated with different diagnostic algorithms to localize cerebrospinal fluid (CSF) rhinorrhea have not been described. METHODS: A decision-tree analysis of imaging modalities used to localize CSF rhinorrhea was performed to compare associated direct costs. The primary outcome was cost, which was determined based on reimbursement data published by the Centers for Medicare and Medicaid Services in 2018. The model was parameterized after a literature review of published studies was performed from 1990 to 2018 to estimate the sensitivity CSF rhinorrhea localization of the following radiographic modalities: high-resolution computed tomography (HRCT), magnetic resonance cisternography (MRC), and CT cisternography (CTC). In addition to base case analysis, 1-way sensitivity analyses were also performed to evaluate the robustness of results to changes in model parameters. RESULTS: Among patients with a high suspicion for CSF rhinorrhea, use of HRCT followed by exploration in the operating room if preliminary HRCT was negative was found to be the optimal localization modality from a cost perspective ($172.25). The next least costly algorithm was HRCT followed by MRC ($294.10). Imaging algorithms beginning with CTC were the next least costly modality ($727.37). Sensitivity analyses generally supported HRCT to be the optimal initial radiographic strategy over a wide range of parameter values. CONCLUSION: This work advocates HRCT as first-line modality to localize CSF rhinorrhea from a cost perspective. Although algorithms beginning with MRC were on average $35 more expensive than those starting with CTC, associated risks of CTC were not modeled and may play a role in decision making.

Rate of rhinosinusitis and sinus surgery following a minimally destructive approach to endoscopic transsphenoidal hypophysectomy.

BACKGROUND: There remains considerable variation in the extent of sinonasal preservation during the approach for endoscopic transsphenoidal hypophysectomy (TSH). We advocate for a minimally destructive approach utilizing turbinate lateralization, small posterior septectomy, no ethmoidectomy, and preservation of nasoseptal flap (NSF) pedicles bilaterally. Due to these factors, this approach may affect the rates of postoperative rhinosinusitis. The objective of this study is to define the rates of postoperative rhinosinusitis in patients undergoing this approach. METHODS: Single institution, retrospective chart review of patients undergoing TSH from 2005 to 2018. RESULTS: A total of 415 patients were identified and 14% developed an episode of postoperative rhinosinusitis within 3 months. These patients were significantly more likely to have had a history of recurrent acute or chronic rhinosinusitis. Most cases were sphenoethmoidal sinusitis managed with 1 to 2 courses of antibiotics. Of patients with postoperative rhinosinusitis, most did not undergo NSF. Average follow-up was 38 months. Six patients (1.4%) underwent post-TSH functional endoscopic sinus surgery (FESS). Average time from TSH to FESS was 26.3 months. Two of these patients had a history of prior chronic rhinosinusitis without polyposis. Two patients underwent revision TSH for recurrent tumor as the primary indication for surgery at time of FESS. Twenty-two-item Sino-Nasal Outcome Test (SNOT-22) scores generally increased immediately postoperatively, but frequently decreased below preoperative level by the time of last follow-up, regardless of whether patients developed rhinosinusitis. CONCLUSION: Sinonasal preservation during TSH is associated with a low rate of postoperative rhinosinusitis requiring FESS and excellent long-term patient reported outcomes. We continue to advocate for sinonasal preservation during pituitary surgery.

Plasmocitoma solitario intracraneal: una presentación inusual / Intracranial solitary plasmacytoma: an unusual presentation

Background: Intracranial solitary plasmacytoma is extremely rare and its location in the clivus is unusual; its clinical presentation is very varied and the diagnostic images are similar to the other tumors in skull-base. Case presentation: 47-year-old woman with initial diagnosis of pituitary macroadenoma, attended with headache, nausea, vomiting, diplopia in the right eye and paralysis of her abducent nerve. She was reoperated by transsphenoidal endoscopic approach, concluding in solitary clivus plasmacytoma by biopsy and immunohistochemistry. Conclusions: Clivus is an unusual location for intracranial plasmacytoma. Early diagnosis, complete study and careful follow-up are required due to its high progression to multiple myeloma(AU)

Introducción: El plasmocitoma solitario intracraneal es extremadamente raro y su localización en el clivus es inusual; su presentación clínica es muy variada y las imágenes diagnósticas son similares a las de otros tumores de la base del cráneo. Reporte de caso: Se presenta el caso de una mujer de 47 años con diagnóstico inicial de macroadenoma hipofisiario, que cursó con cefalea, náuseas, vómitos, diplopía en ojo derecho y parálisis de su nervio abducente. Fue reintervenida por vía transesfenoidal endoscópica, concluyendo en plasmocitoma solitario del clivus por biopsia e inmunohistoquímica. Conclusiones: El clivus es una localización inusual para plasmocitoma intracraneal, se requiere un diagnóstico precoz, estudio completo y seguimiento cuidadoso por su alta progresión a mieloma múltiple(AU)

Adenosine-induced transient hypotension for carotid artery injury during endoscopic skull-base surgery: case report and review of the literature.

BACKGROUND: As the management of ventral skull-base pathology has transitioned from open to endonasal treatment, there has been an increased focus on the prevention and endoscopic endonasal management of internal carotid artery (ICA) and major vascular injury. The use of adenosine to induce transient hypotension or flow arrest has been previously described during intracranial aneurysm surgery; however, there have been no reports of the technique being used during endonasal skull-base surgery to achieve hemostasis following major vascular injury. METHODS: Case report (n = 1) and literature review. RESULTS: A 25-year-old female underwent attempted endoscopic endonasal resection of an advanced right-sided chondrosarcoma. During resection of the tumor, brisk arterial bleeding was encountered consistent with focal injury to the right cavernous ICA. Stable vascular hemostasis could not be achieved with tamponade. An intravenous bolus dose of adenosine was administered to induce a transient decrease in systemic blood pressure and facilitate placement of the muscle patch over the direct site of vascular injury. The patient subsequently underwent endovascular deconstruction of the right ICA. CONCLUSION: This is the first reported use of adenosine to induce transient hypotension for a major vascular injury sustained during endonasal skull-base surgery. Based on well-established safety data from neurosurgical application, adenosine has the potential to be used as a safe and effective adjunctive technique in similar endonasal circumstances and may represent an additional tool in the armamentarium of the skull-base surgeon. Surgeons should consider having adenosine available when a risk of ICA injury is anticipated.

ICAR: endoscopic skull-base surgery.

BACKGROUND: Endoscopic skull-base surgery (ESBS) is employed in the management of diverse skull-base pathologies. Paralleling the increased utilization of ESBS, the literature in this field has expanded rapidly. However, the rarity of these diseases, the inherent challenges of surgical studies, and the continued learning curve in ESBS have resulted in significant variability in the quality of the literature. To consolidate and critically appraise the available literature, experts in skull-base surgery have produced the International Consensus Statement on Endoscopic Skull-Base Surgery (ICAR:ESBS). METHODS: Using previously described methodology, topics spanning the breadth of ESBS were identified and assigned a literature review, evidence-based review or evidence-based review with recommendations format. Subsequently, each topic was written and then reviewed by skull-base surgeons in both neurosurgery and otolaryngology. Following this iterative review process, the ICAR:ESBS document was synthesized and reviewed by all authors for consensus. RESULTS: The ICAR:ESBS document addresses the role of ESBS in primary cerebrospinal fluid (CSF) rhinorrhea, intradural tumors, benign skull-base and orbital pathology, sinonasal malignancies, and clival lesions. Additionally, specific challenges in ESBS including endoscopic reconstruction and complication management were evaluated. CONCLUSION: A critical review of the literature in ESBS demonstrates at least the equivalency of ESBS with alternative approaches in pathologies such as CSF rhinorrhea and pituitary adenoma as well as improved reconstructive techniques in reducing CSF leaks. Evidence-based recommendations are limited in other pathologies and these significant knowledge gaps call upon the skull-base community to embrace these opportunities and collaboratively address these shortcomings.

International consensus statement on endoscopic skull-base surgery: executive summary.

BACKGROUND: Endoscopic skull-base surgery (ESBS) is a rapidly growing discipline that often combines the expertise of otolaryngology-head and neck surgeons and neurosurgeons to provide care for these challenging conditions. As the field has grown, so too has the literature evaluating this surgical approach and the challenges and complications associated with these interventions. An international, multidisciplinary effort to critically evaluate and grade the current literature on ESBS has resulted in the International Consensus Statement on Endoscopic Skull Base Surgery (ICAR:SB). This Executive Summary highlights the key findings of the ICAR:SB document. METHODS: Following the prior methodology of the ICAR statements, the ICAR:SB document consists of 98 topics in ESBS that underwent a systematic review. When sufficient evidence exists, an evidence-based review with recommendation (EBRR) or evidence-based review (EBR) was created and then underwent an iterative review process until consensus was achieved. This Executive Summary recapitulates these findings. RESULTS: This summary complies the EBR and EBRR from the ICAR:SB document in the management of numerous skull-base pathologies including cerebrospinal fluid rhinorrhea, intradural tumors, sinonasal malignancies, and clival tumors, as well as the key issues of reconstruction after and the complications associated with ESBS. CONCLUSION: The ICAR:SB Executive Summary recaps the evidenced-based recommendations concerning the advantages, limitations and challenges of ESBS in the management of diverse skull-base pathologies. Although multifactorial in nature, the overall level of evidence in ESBS is modest. This represents an opportunity to address these knowledge gaps moving forward.

Surgical management of rhinosinusitis in endoscopic-endonasal skull-base surgery.

BACKGROUND: Endoscopic-endonasal skull base surgery (ESBS) provides an important approach to select pathologies. There remains a paucity of data, however, regarding morbidity in patients undergoing ESBS with comorbid acute rhinosinusitis (ARS), a fungal ball (FB), or chronic rhinosinusitis (CRS). METHODS: A retrospective database review between January 2008 and January 2013 identified 35 patients with concurrent skull-base pathology and refractory ARS, FB, CRS, and CRS with nasal polyposis (CRSP) who underwent endoscopic sinus surgery (ESS) and ESBS. RESULTS: Two of 35 (5.7%) had an FB, 3 of 35 (8.6%) had ARS, 19 of 35 (54.2%) had CRSP, and 11 of 35 (31.4%) had CRS. Five of 35 (14.3%) were staged procedures whereas 30 of 35 (85.7%) underwent concurrent ESS and ESBS. Four patients (80%) who were staged carried diagnoses of an FB and ARS. Two patients in the concurrent group required revision ESS for recurrent polyposis. There were no cases of intraorbital or intracranial infectious complications. CONCLUSION: Management of the paranasal sinuses is paramount to maintain healthy sinonasal function in patients undergoing ESBS. In our experience, most cases of CRS and CRSP can be surgically managed at the time of ESBS without increased risk of intracranial infection. Patients with ARS at the time of surgery or an FB should be staged to avoid postoperative ESBS morbidity.

Perforation of a nasoseptal flap does not increase the rate of postoperative cerebrospinal fluid leak.

BACKGROUND: The nasoseptal flap (NSF) has been shown to be a valuable addition to the reconstructive armamentarium of the endoscopic skull-base surgeon. We aimed to evaluate the rate of postoperative cerebrospinal fluid (CSF) leak after use of a NSF that had a small tear during harvest. METHODS: After Institutional Review Board (IRB) approval, we analyzed our database of patients undergoing skull-base resection. We included all patients who had a NSF reconstruction, septoplasty, and/or spur on preoperative computed tomography (CT) imaging. We then evaluated video of each procedure to determine if a tear occurred in the NSF during harvest. Patient records were reviewed to determine if a postoperative CSF leak occurred. RESULTS: We evaluated video of 21 patients who underwent a skull-base resection, were reconstructed with a NSF, and had either a septoplasty or evidence of a septal spur on CT imaging. Of these 21 cases, 11 small tears occurred during harvest of the NSF flap and none of the patients with a torn NSF had a postoperative CSF leak. CONCLUSION: Our series shows a 0% postoperative CSF leak rate in patients undergoing skull-base reconstruction with a NSF that was torn during harvest. Small tears in the NSF do not seem to affect postoperative CSF leak rates.