Rosai-Dorfman sphenoorbital histiocytosis with intraparenchymal invasion: Do we have to consider this skull base pathology as a malignant disease?

Background: Rosai-Dorfman disease (RDD) is a rare type of histiocytosis that can manifest with diverse symptoms. It usually presents with systemic involvement, and only a few cases have been reported at the level of the skull base. RDD typically follows a benign course during the progression of the disease. In this particular case reported, after the skull base invasion, the disease started to infiltrate the brain parenchyma. Our objective for this case report was to present this particular progression pattern and the nuances of its surgical treatment. In addition, a revision of the current literature was performed about skull base RDD with intracranial invasion and brain parenchyma infiltration not previously described. Case Description: We are presenting the case study of a 57-year-old male patient who was experiencing severe headaches and an increase in volume in the right fronto-orbital region. On clinical examination, no neurologic clinical symptoms were observed. Contrast computed tomography and magnetic resonance imaging showed a tumor mass that affected the right orbit, frontal paranasal sinus, greater sphenoid wing, and right frontal lobe with moderate adjacent brain edema. The patient underwent surgery using an extended pterional approach with intracranial, orbital decompression, and frontal sinus cranialization, accompanied by frontal lobe tumor resection. Neuropathologic diagnosis revealed a Rosai-Dorfman histiocytosis disease. Conclusion: The etiopathogenesis of RDD is still not completely understood. The current literature considers this disease to have a predominantly benign course. Nevertheless, as we have shown in this case, it may, in some cases, present direct parenchymal invasion. We consider that prompt surgical treatment should be ideal to avoid the local and systemic progression of the disease.

Management of Severe Dysphonia and Dysphagia Following Lateral Skull Base Surgery.

OBJECTIVES: Lateral skull base surgeries pose a risk of injuring the lower cranial nerves, leading to potential postoperative complications such as dysphonia and dysphagia. Conservative treatments have shown limited efficacy in addressing these resultant voice and swallowing dysfunctions, significantly impacting patient quality of life. This study aims to evaluate the safety and effectiveness of a combined surgical approach involving autologous fat injection laryngoplasty (AFIL) and transcervical cricopharyngeal myotomy (TCPM) in patients suffering from severe dysphonia and dysphagia following lateral skull base surgery. METHODS: A retrospective analysis was conducted on 16 patients who underwent concurrent AFIL and TCPM to improve severe dysphonia and dysphagia following lateral skull base surgery. Preoperative and postoperative assessments of voice and swallowing functions were performed using the Voice Handicap Index-10 (VHI-10), GRBAS scale, maximum phonation time (MPT), the Chinese version of Swallow Quality-of-Life Questionnaire (CSWAL-QOL), and videofluoroscopic swallowing studies (VFSS). RESULTS: The results demonstrated notable improvements in voice quality and swallowing function. The VHI-10 score improved significantly from a preoperative mean of 32.06 ± 4.92 to a postoperative 9.06 ± 5.24. The results of the perceptual parameters of the GRBAS scale also improved significantly. The MPT increased from a preoperative average of 3.91 ± 1.00 seconds to 9.14 ± 2.44 seconds postoperatively. The CSWAL-QOL scores significantly improved from a preoperative score of 92.44 ± 17.75 to 130.19 ± 26.07 postoperatively. The VFSS-SWAL scores decreased from 6.63 ± 1.36 before surgery to 3.56 ± 1.58 after surgery. Similarly, the Penetration Aspiration Scale (PAS) scores significantly dropped from 6.38 ± 1.05 preoperatively to 2.93 ± 1.48 postoperatively. Nine out of 11 patients were able to have their gastric tubes successfully removed after surgery. There were no significant postoperative complications. CONCLUSION: Concurrent AFIL and TCPM present a promising reconstructive method for patients experiencing severe dysphonia and dysphagia following lateral skull base surgery, highlighting its value in the postoperative management of complex lower cranial nerve injuries.

Overcoming Challenges: Haemostasis in a Clival Plasmacytoma.

Solitary plasmacytomas of clivus are a rare entity, having only less than 20 cases reported so far in the literature; its diagnosis and management don't have a gold standard. Although endoscopic skull base surgery (ESBS) is less morbid, it poses a challenge to the surgeon because of the critical location close to vital structures and intraoperative bleeding. Here we present a case report on managing this rare entity and our challenges while dealing with this vascular tumour.

Skull Base Chordoma in a Young Lady - A Tale of Mismanagement and Redemption: A Case Report and Review of Literature.

Skull base chordomas are a rare entity that requires multidisciplinary decision-making for management. We report a case wherein the patient was initially mismanaged at a peripheral centre, and was then redeemed by a multidisciplinary tumor board decision-making and specialized surgical procedures. We also present a brief review of the therapeutic options.

Comparative Cross Sectional Prospective Study of Anterior Skull Base Thickness in Spontaneous Cerebrospinal Fluid Rhinorrhoea vs Matched Controls.

Cerebrospinal fluid (Csf) leak is the leakage of CSF from subarachnoid space into the nasal cavity.Csf rhinorrhoea is classified as traumatic and non traumatic causes (Ommaya et al. J Neurol Neurosurg Psychiatry 31(3):214, 1968). Spontaneous csf leaks occur due to increased intracranial pressure. Early diagnosis of spontaneous csf leaks may prevent complications like meningitis. This was a cross sectional prospective study done in a tertiary care hospital. Group A-spontaneous csf leak patients and Group B- Non csf leak matched controls. The anterior skull base thickness from fovea ethmoidalis, cribriform plate and lateral lamella were compared between the groups using high resolution computed tomography of paranasal sinus with 2 mm cuts. The anterior skull base thickness was measured by a senior radiologist in our tertiary centre. In this study, total of forty six patients were included, twentythree in each group. The Mean age in Group A and Group B was 48.95 and 48.78 respectively. Body mass index (BMI) was compared between the two groupsand spontaneous csf leak patients had higher value than non csf leak controls. The mean anterior skull base thickness of Group A (cribriform plate-0.56 mm, lateral lamella-0.66 mm, Fovea ethmoidalis-0.91 mm) was lower than Group B (cribriform plate-0.86 mm, lateral lamella-0.84 mm, Fovea ethmoidalis-0.97 mm) which was statistically significant (p value-< 0.05).

Recurrent Hydatid Disease of Temporal Bone and Skull Base: A Case Report and Literature Review.

Hydatid disease is a parasitic infestation caused by Echinococcus granulosus. The disease is rare in the head and neck region with varying presentations. We present a rare case of recurrent hydatid disease of the temporal bone with intracranial involvement; and the treatment thereof. Hydatid disease is endemic in few parts of the world, its occurrence in head and neck region is very rare. The commonest causative organism is E. granulosus giving rise to cystic hydatid disease. Most of the former are asymptomatic, but can give rise to symptoms because of their mass effects or rupture. Our case is a 38 year male presenting to ENT department with recurrent left ear discharge, giddiness, headache and facial palsy having operated elsewhere twice in the past. The patient was investigated by Computed Tomography (CT) scanning and Magnetic Resonance Imaging (MRI) of temporal bones, head and neck regions. Which showed soft tissue attenuation of middle ear cleft and multiple cystic lesions in the middle and posterior cranial fossae indicating intracranial extension of disease. We operated for left subtotal petrosectomy with vestibular labyrinthectomy. During the perioperative period he was treated with Albendazole. Patient remains clinically and radiologically asymptomatic (post surgery 1 year) till date of this manuscript submission. Hence, we report the recurrent hydatid cyst in the temporal bone and skull base, which was managed by combination of surgical and medical treatment.

Letter to the Editor: "Exploring optimal microscopic keyhole access to the skull base: an anatomical evaluation of transciliary supraorbital and transpalpebral orbitofrontal craniotomy approaches".

This letter to the editor examines the recent comparative study by Santos et al. (2024) on transciliary supraorbital (TCA) and transpalpebral (TPA) approaches for skull base access. The original article offers valuable insights into the anatomical distinctions and potential clinical applications of each approach. The letter praises the methodical analysis presented in the study while proposing future directions incorporating advanced imaging technologies and expanded clinical trials to enhance surgical precision and outcomes. Additionally, it suggests integrating longitudinal studies to evaluate patient outcomes, thereby refining the procedural choice based on specific clinical scenarios.

Artificial Intelligence in Temporal Bone Imaging: A Systematic Review.

OBJECTIVE: The human temporal bone comprises more than 30 identifiable anatomical components. With the demand for precise image interpretation in this complex region, the utilization of artificial intelligence (AI) applications is steadily increasing. This systematic review aims to highlight the current role of AI in temporal bone imaging. DATA SOURCES: A Systematic Review of English Publications searching MEDLINE (PubMed), COCHRANE Library, and EMBASE. REVIEW METHODS: The search algorithm employed consisted of key items such as 'artificial intelligence,' 'machine learning,' 'deep learning,' 'neural network,' 'temporal bone,' and 'vestibular schwannoma.' Additionally, manual retrieval was conducted to capture any studies potentially missed in our initial search. All abstracts and full texts were screened based on our inclusion and exclusion criteria. RESULTS: A total of 72 studies were included. 95.8% were retrospective and 88.9% were based on internal databases. Approximately two-thirds involved an AI-to-human comparison. Computed tomography (CT) was the imaging modality in 54.2% of the studies, with vestibular schwannoma (VS) being the most frequent study item (37.5%). Fifty-eight out of 72 articles employed neural networks, with 72.2% using various types of convolutional neural network models. Quality assessment of the included publications yielded a mean score of 13.6 ± 2.5 on a 20-point scale based on the CONSORT-AI extension. CONCLUSION: Current research data highlight AI's potential in enhancing diagnostic accuracy with faster results and decreased performance errors compared to those of clinicians, thus improving patient care. However, the shortcomings of the existing research, often marked by heterogeneity and variable quality, underscore the need for more standardized methodological approaches to ensure the consistency and reliability of future data. LEVEL OF EVIDENCE: NA Laryngoscope, 2024.

Supporting left-handed trainees in sinus and skull base surgery: A call for inclusive ergonomics.

KEY POINTS: The surgeon's hand dominance impacts ergonomics in endoscopic endonasal surgery. Left-handed trainees experience difficulty learning certain surgical techniques. OR adjustments optimize ergonomics for left-handed trainees without compromising others.

Endoscopic reconstruction to primary empty sella: "7 E" technique.

We present the seven "E" technique step by step for the reconstruction of the empty sella with an illustrative case.

Immunoglobulin D-Lambda Multiple Myeloma Initially Presenting in the Sphenoid Sinus, Orbital Apex, and Skull Base: A Systematic Review with a Case Report.

Objectives Multiple myeloma (MM) with initial manifestations in the sphenoid sinus, orbital apex, and skull base is exceedingly rare. A systematic review was conducted to investigate the epidemiology and advancements . Methods Relevant cases were identified by searching CNKI, WanFang Data, CQVIP databases, PubMed, Embase, and Web of Science. Additionally, we present a case of IgD-λ (immunoglobulin D-lambda) MM with initial symptoms of dizziness, unilateral pain, blindness, and ophthalmoplegia, leading to a 4-month overall survival. Strictly based on PRISMA standards, we included and summarized existing cases and reflected our case. Results Our systematic review includes 34 case reports, revealing 67.6% of patients initially presented with diplopia and 44.1% underwent endoscopic procedures, notably with only two cases of IgD-λ subtype. In our case, we performed an endoscopic wide trans-ethmoidal sphenoidotomy and biopsy of the skull base and orbital apex lesion. Postoperative pathology confirmed a highly active plasmacytoma, clinically diagnosed as IgD-λ MM with a TP53 deletion mutation and multiple extramedullary metastases. A range of diagnostic tools was employed, including hemoglobin, immunoglobulin, urinary protein analysis, positron emission tomography-computed tomography (CT), bone marrow cytology, and gene detection. Conclusion The subtle clinical manifestations of IgD-λ MM in the paranasal sinuses and skull base hinder early diagnosis. There is a paucity of literature describing MM initially presenting in these locations. CT/magnetic resonance scans are necessary to identify characteristic bone destruction. An endoscopic approach is popular for tissue biopsy. Bone marrow biopsy with a smear, serum or urine protein electrophoresis, and immunofixation electrophoresis are crucial upon the appearance of target organ damage.

The Incidence of Radiologic Evidence of Sinusitis Following Endoscopic Pituitary Surgery: A Multi-Center Study.

Background: Endoscopic endonasal skull base surgery has become a viable alternative to open procedures for the surgical treatment of benign and malignant lesions in the sinonasal and skull base regions. As in sinus surgery, skull base surgery may cause crusting and posterior rhinorrhea, particularly when a nasoseptal flap is required for skull base reconstruction. Post-operative radiological sinonasal findings have been reported previously with no clear correlation with intraoperative decision-making. As in open surgery, endoscopic surgery is not standardized and there is variability in the intervention to assist with exposure and skull base repair. These modifications, including middle turbinate resection, nasoseptal flap, fat graft, and maxillary antrostomy have the potential for nasal morbidity. The aim of this study was to evaluate whether specific interventions during surgery or specific patient and tumor characteristics harbor a more significant risk of causing nasal morbidity post-operatively, as demonstrated by post-operative imaging. Methods: A retrospective analysis of all patients who underwent endoscopic endonasal skull base surgery for pituitary lesions at two major referral centers was performed. Data on demographic, clinical, and pathological features were collected, and pre- and post-operative imaging studies (computed tomography (CT) and magnetic resonance imaging (MRI)) were reviewed and scored according to the Lund-Mackay (LM) scoring system. Results: The study included 183 patients. Radiographic evidence of sinusitis was observed in 30 patients (LM score > 4) in post-operative imaging studies. Patients who underwent middle turbinectomy or nasoseptal flap were found to have significantly higher LM scores on follow-up imaging. A nasoseptal flap was found to be associated with an average increase in LM score of 1.67 points and middle turbinectomy with an average increase of 2.21 points. There was no correlation between tumor size and findings that were compatible with sinusitis on post-operative imaging. Conclusions: The findings of the present study suggest that endoscopic endonasal skull base surgery is associated with radiological evidence of sinusitis. Nasoseptal flap reconstruction and middle turbinectomy were strongly associated with radiographic sinusitis and should be judiciously performed during surgery. A clinical correlation is needed for further recommendations.

Upright CT-based evaluation of the effects of posture on skull-base reconstruction after endoscopic endonasal surgery.

Cerebrospinal fluid (CSF) leakage is a common complication associated with endoscopic endonasal skull-base surgery (EESBS). Postoperative mobilization-associated postural changes are considered to cause CSF leakage. However, no study has demonstrated a robust relationship between postural changes and CSF leakage. We used upright computed tomography (CT) to clarify the effects of postural changes on the reconstructed skull base (RSB) after EESBS. Thirty patients who underwent EESBS at our institution were prospectively included, and their upright and supine CTs were compared to measure morphological changes in the RSB. Patient clinical data were also collected from medical charts and surgical videos, and their relationships with morphological changes were assessed. In upright CTs, the RSB shifted intracranially by 0.94 (0.0-2.9) mm on average. This shift was larger in cases with lesions extending to the sphenoid sinus, dural defects, intraoperative pulsation of the RSB, and large bone windows. The direction of the change was opposite to intuitive movement driven by gravity because of reduced intracranial pressure in the sitting position. Thus, these shifts can be directly associated with postoperative CSF leakage caused by reconstruction material displacement. Skull-base reconstruction and postoperative postural management accounting for these morphological changes may be necessary for preventing CSF leakage.

Combined Endonasal and Trans-septal approach to Achieve Binostril Access in Endoscopic Skull Base Approaches to Minimise Nasal Morbidity: A technical note.

INTRODUCTION: Over the years, feasibility & safety of EEAs has become well established & the focus has now shifted to minimising the nasal morbidity. To this end, several modifications in nasal stage have been described that have focussed primarily on preservation of nasal mucosa on right side of nasal cavity (NC). However, the issue of nasal mucosal preservation on left side of NC has largely been ignored. In this paper, the author describes a modified technique that can eliminate mucosal damage in left NC. METHOD: In modified technique, trans-septal approach is utilised on left & endonasal on right side. A hemitransfixion incision is used to raise left submucosal tunnel. The mucosa of tunnel lies laterally in apposition with lateral nasal wall, thereby protecting it from injury by repeated passage of instruments. When tunnel mucosa is pushed back medially, left NC appears absolutely normal without any evidence of mucosal damage. RESULTS: Combined endonasal & trans-septal technique for nasal stage was performed in 51 patients with sellar/suprasellar lesions. Nonfunctional pituitary adenomas were the most common pathology (macroadenomas-n=14; Giant adenomas-n=10) followed by functional adenomas (acromegaly-n=10; prolactinomas- n=3; Cushings's disease- n=1), craniopharyngiomas (n=6), clival tumours (n=5), & tuberculum sella meningiomas (n=2). CONCLUSIONS: A combination of endonasal and trans-septal approaches utilises the advantages of both endoscopic & microscopic approaches sans the disadvantage of restricted space seen in microscopic approaches. It makes binostril approach least disruptive to left nasal mucosa & thus can reduce overall morbidity of EEAs.

Surgical resection and reconstruction techniques for jugular foramen schwannoma.

INTRODUCTION: Jugular foramen schwannomas present formidable challenges due to their deep-seated location and complex anatomical constraints, leading to significant difficulties in tumor excision, postoperative complications further hinder surgical interventions in this area. We aim to explore and summarize surgical and reconstruction techniques for jugular foramen schwannomas to enhance patient outcomes. MATERIALS AND METHODS: In a retrospective analysis, we reviewed the surgical approaches and reconstruction techniques utilized in 31 patients undergoing surgical resection for jugular foramen schwannomas from January 2018 to the present. Our goal was to summarize the materials and methods used for skull base reconstruction in this region and propose a clinically applicable procedural framework for surgical intervention. RESULTS: Results revealed that 28 patients underwent treatment via the far lateral paracondylar approach, while 3 patients opted for the suboccipital retrosigmoid approach. Among them, 15 patients underwent surgical cavity tamponade. Additionally, we summarized three methods of dural reconstruction in the surgical area. Postoperative temporary complications showed varying degrees of improvement during follow-up, leading to an overall favorable prognosis. CONCLUSION: Our study presents clinical insights into the surgical resection and skull base reconstruction of jugular foramen schwannomas. We discuss the selection of surgical approaches, intraoperative landmarks, and reconstruction techniques aimed at improving patient outcomes effectively.

Reuse of Nasoseptal Flaps for Endoscopic Endonasal Skull Base Reconstruction.

Introduction Pedicled nasoseptal flap (NSF) placement is a critical component of skull base reconstruction after endoscopic endonasal approaches (EEAs). The effectiveness of NSF reuse has not been thoroughly studied. Prior reports using flaps harvested at one center and reused at another may have technical variability bias. Methods We identified patients who underwent both their initial and NSF-reused surgeries at Weill Cornell Medical College from 2004 to 2022 using a prospective database of all EEAs. Surgical pathology, intraoperative leak grade, use of cerebrospinal fluid (CSF) diversion and skull base coverage were examined. The primary outcome measure was occurrence of CSF leak. Results Fourteen patients (six women, eight men) underwent 14 first time and 14 revision operations with median age of 36.6 years (interquartile range [IQR]: 23.9-61.3) at the time of the NSF reuse. The median interval between the first NSF use and reuse was 70.6 months (IQR: 16.6-87). Eight patients were operated on for pituitary adenoma. Nonadenomas included three craniopharyngiomas and one case each of epidermoid, ependymoma, and chordoma. There were 16 high-flow, 8 low-flow intraoperative leaks, and 4 with no leak. CSF diversion was used in 24 operations. There were three postoperative leaks, one after a first operation and two after NSF reuse. All postoperative CSF leaks, whether first or second operations, occurred in cases with both high-flow intraoperative CSF leak and incomplete NSF coverage ( p = 0.006). Conclusion NSF reuse is effective at preventing postoperative CSF leak. The primary predictors of leak are high-flow intraoperative leak and inadequate defect coverage with NSF, regardless of the operation number.

Minimally Invasive Transnasal Approach to the Anteromedial Temporal Fossa and Lateral Sphenoid Using a Novel Landmark between Periorbita and Periosteum of the Pterygopalatine Fossa: A Cadaveric Study.

The anteromedial temporal region and the lateral wall of the sphenoid can be the site of an array of pathology including trigeminal schwannoma, encephalocele, cholesterol granuloma of the petrous apex, malignancy, infection, and sellar pathology extending to the lateral cavernous sinus. Approaches to this region are technically challenging and the existing approach requires sacrifice of all of the turbinates including the nasolacrimal duct, which can cause postoperative complications. We describe a novel anatomical landmark between the periorbita and the periosteum of the pterygopalatine fossa (which is located at the inferolateral periorbital periosteal line [ILPPL]). The posterior one-third of the incision line lies between the foramen rotundum and the superior orbital fissure, which is proximal to the maxillary strut. A 1.5-cm incision can divide the orbital and pterygoid contents and lead us to the posterior inferolateral orbital region, anteromedial temporal region, lateral wall of the sphenoid sinus, and lateral wall of the cavernous sinus. A combined multiangled approach to the ILPPL will enable us to preserve all of the turbinates and the septum, and the nasolacrimal duct, allowing for the preservation of the physiological function and pedicled flaps, such as the middle turbinate, inferior turbinate, and septal membrane flap. The ILPPL is a simple, effective, and novel landmark for the minimally invasive approach to the anteromedial temporal fossa.

Does Time to Initiation of Adjuvant Radiotherapy Affect Reconstruction Outcomes after Endoscopic Resection of Skull Base Malignancies?

Introduction and Objective It is unclear if the length of the time interval to initiation of adjuvant radiation therapy (RT) after endoscopic endonasal surgery affects reconstruction outcomes. In this study we present our experience with adjuvant RT after endoscopic endonasal procedures, to determine if the time to RT after surgery impacts post-RT reconstruction complication rates. Methods A retrospective cohort study of 164 patients who underwent endoscopic endonasal surgery between 1998 and 2021 was conducted. Using Cox proportional hazard ratios (HRs), we evaluated several variables and the complications that occurred during the 1-year period after starting RT. Results Seventy-eight (47.5%) and eighty-six patients (52.5%) received RT before and after the sixth postoperative week, respectively. The overall post-RT complication rates were 28%, most of these were severe infections ( n = 20, 12.2%) and delayed CSF leak ( n = 4, 2.5%). There was no significant difference in the post-RT complications between the patients who received postoperative RT before or after the sixth operative week (HR: 1.13; 95% confidence interval: 0.63-2.02; p = 0.675 ). Univariate analysis demonstrated negative impact associated with smoking history ( p = 0.015 ), the use of neoadjuvant chemotherapy ( p = 0.0001 ), and the use of photon therapy ( p = 0.012 ); and we found a positive impact with the use of multilayer reconstruction techniques (overall, p = 0.041 ; with fat, p = 0.038 ; and/or fascia graft, p = 0.035 ). After a multivariate analysis only, smoking history was an independent risk factor for post-RT complications ( p = 0.012 ). Conclusion Delaying RT for more than 6 weeks after endoscopic endonasal surgery does not provide a significant benefit for reconstruction outcomes. However, special attention may be warranted in patients with smoking history who have received neoadjuvant chemotherapy, or in patients who will receive photon-based RT after surgery as these groups were found to have increased complication rates post-RT.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Endoscopic Endonasal Middle-Inferior Clivectomy, Odontoidectomy, and Far-Medial Approach.

Introduction The clival, paraclival, and craniocervical junction regions are challenging surgical targets. To approach these areas, endoscopic endonasal transclival approaches (EETCAs) and their extensions (far-medial approach and odontoidectomy) have gained popularity as they obviate manipulating and working between neurovascular structures. Although several cadaveric studies have further refined these contemporary approaches, few provide a detailed step-by-step description. Thus, we aim to didactically describe the steps of the EETCAs and their extensions for trainees. Methods Six formalin-fixed cadaveric head specimens were dissected. All specimens were latex-injected using a six-vessel technique. Endoscopic endonasal middle and inferior clivectomies, far-medial approaches, and odontoidectomy were performed. Results Using angled endoscopes and surgical instruments, an endoscopic endonasal midclivectomy and partial inferior clivectomy were performed without nasopharyngeal tissue disruption. To complete the inferior clivectomy, far-medial approach, and partially remove the anterior arch of C1 and odontoid process, anteroinferior transposition of the Eustachian-nasopharynx complex was required by transecting pterygosphenoidal fissure tissue, but incision in the nasopharynx was not necessary. Full exposure of the craniocervical junction necessitated bilateral sharp incision and additional inferior mobilization of the posterior nasopharynx. Unobstructed access to neurovascular anatomy of the ventral posterior fossa and craniocervical junction was provided. Conclusion EETCAs are a powerful tool for the skull-base surgeon as they offer a direct corridor to the ventral posterior fossa and craniocervical junction unobstructed by eloquent neurovasculature. To facilitate easier understanding of the EETCAs and their extensions for trainees, we described the anatomy and surgical nuances in a didactic and step-by-step fashion.

Functional outcomes after retrosigmoid approach to the cerebellopontine angle: Observations from a single-center experience of over 13 years.

Introduction: Accessing the posterior base of the skull is complex because of the vital neurovascular structures in the area. However, the retrosigmoid approach (RSA) offers a solution to this challenge. Research question: To analyze surgical outcome of RSA. Material and methods: This study involved a retrospective review of patient charts from a single center, focusing on the surgical procedure and outcomes following the operation. Results: The study included 517 patients suffering from conditions like vestibular schwannomas (VS), metastatic cancers, and trigeminal neuralgia. The most frequent symptoms reported were balance disorders (42.7%), hearing loss (36.5%), walking difficulties (21.2%), headaches (18.9%), facial pain (17.1%), issues with trigeminal nerve function (14.1%), cerebellar dysfunction (13.5%), and facial nerve paralysis (10.2%). The rate of complications stood at 21.1%, with 11.3% of patients needing revision surgery. The median score on the Clavien-Dindo scale was 2, and the rate of mortality related to surgery was 1.0%. Permanent symptom improvement was seen in 72.1% of cases. Temporary new deficits occurred in 43.2% of patients, with facial nerve paralysis being the most common (14.1%). No significant correlation was found between the size of the craniotomy and the extent of tumor resection (p = 0.155), except in the case of VS (p = 0.041). Larger craniotomy sizes were associated with higher rates of complications (p = 0.016), especially CSF leaks (p = 0.006). Complications significantly affected the likelihood and number of new deficits (p < 0.001 for both), particularly postoperative bleeding (p = 0.019, p = 0.001), CSF leaks (p = 0.026, p = 0.039), and hydrocephalus (p = 0.050, p = 0.007). Conclusions: The potential for complications related to the surgical approach cannot be overlooked. The size of the tumor should not dictate larger surgical approaches due to the associated increase in postoperative complications; a tailored approach that considers the precise tumor location and pathology is crucial for optimizing postoperative outcomes.