360 Degrees Endoscopic Access to and Through the Orbit.

The treatment of pathologies located within and surrounding the orbit poses considerable surgical challenges, due to the intricate presence of critical neurovascular structures in such deep, confined spaces. Historically, transcranial and craniofacial approaches have been widely employed to deal with orbital pathologies. However, recent decades have witnessed the emergence of minimally invasive techniques aimed at reducing morbidity. Among these techniques are the endoscopic endonasal approach and the subsequently developed endoscopic transorbital approach (ETOA), encompassing both endonasal and transpalpebral approaches. These innovative methods not only facilitate the management of intraorbital lesions but also offer access to deep-seated lesions within the anterior, middle, and posterior cranial fossa via specific transorbital and endonasal corridors. Contemporary research indicates that ETOAs have demonstrated exceptional outcomes in terms of morbidity rates, cosmetic results, and complication rates. This study aims to provide a comprehensive description of endoscopic-assisted techniques that enable a 360° access to the orbit and its surrounding regions. The investigation will delve into indications, advantages, and limitations associated with different approaches, while also drawing comparisons between endoscopic approaches and traditional microsurgical transcranial approaches.

Comparative Optics of the Surgical Microscope and Rigid Endoscopes in Neurosurgery.

This chapter is intended to provide a brief overview of the optics of surgical microscopes and rigid endoscopes, with the aim of providing the reader with the principles dictating the nature of surgical visualization when either of the visual control systems is used. It is not by any means geared toward elaborating on the detailed optical physics of these systems, which is beyond the scope and objective of this chapter.

Endoscope-assisted microvascular decompression in hemifacial spasm with a teflon bridge.

BACKGROUND: Microvascular conflicts in hemifacial spasm typically occur at the facial nerve's root exit zone. While a pure microsurgical approach offers only limited orientation, added endoscopy enhances visibility of the relevant structures without the necessity of cerebellar retraction. METHODS: After a retrosigmoid craniotomy, a microsurgical decompression of the facial nerve is performed with a Teflon bridge. Endoscopic inspection prior and after decompression facilitates optimal Teflon bridge positioning. CONCLUSIONS: Endoscope-assisted microsurgery allows a clear visualization and safe manipulation on the facial nerve at its root exit zone.

Purely endoscopic and endoscope-assisted approaches to lesions of the third ventricle in pediatric age-a technical collection.

BACKGROUND: One of the main difficulties in third ventricle surgery is its deep and central location within the brain, surrounded by many eloquent neurovascular structures. Such anatomical environment obviously makes it very hard to safely approach and excise lesions in there. METHODS: The introduction of the surgical microscope into the neurosurgical field undoubtedly played an important and pivotal role in improving the surgical results and increasing the safety of operations in and around the third ventricle. Although the surgical microscope remained the gold standard of intraoperative visualization for many decades, the advent of endoscopes revolutionized surgery of the third ventricle. Neuroendoscopic procedures for lesions of the third ventricle encompass a greatly variable array of endochannel, endoscope-assisted and endoscope-controlled techniques. CONCLUSION: In this collection on purely endoscopic and endoscope-assisted approaches to lesions of the third ventricle in pediatric age, the readership is presented with a selected group of these operations performed by experts in the field, shedding light mainly on their technical aspects and surgical pearls. The text description in each article is supplemented by a surgical video.

Endoscope-assisted microsurgical resection of a third ventricular immature teratoma.

BACKGROUND: Reaching a tumor within the third ventricle is challenging, and planning an accessible trajectory is crucial without injuring the surrounding structures. We report a 5-year-old boy presented with headache and a seizure where sequential MRI brain studies in a short time period revealed a rapid growing immature teratoma within the third ventricle with hydrocephalic changes. Several management procedures were performed for CSF diversion and medical treatment of the tumor with chemotherapy and stem cell therapy. The tumor was rapidly growing, and surgical excision was decided. Total resection was achieved via endoscope-assisted microsurgical transcallosal approach. Seven years after surgery, the patient experienced no recurrence of the tumor with a favorable clinical condition. CONCLUSION: We report a rare case of posterior third ventricular immature teratoma where the endoscope-assisted microsurgical technique was implemented with favorable long-term postoperative outcome.

Neuroendoscopy in the management of pineal region tumours in children.

INTRODUCTION: Pineal region tumours (PRTs) are more common in children and represent a wide variety of lesions. The practise of a radiation test dose is obsolete and a biochemical/histological diagnosis is recommended before further therapy. Many patients present with hydrocephalus. Advances in neuroendoscopic techniques have allowed safe and effective management of this obstructive hydrocephalus with an opportunity to sample cerebrospinal fluid (CSF) and obtain tissue for histopathology. Definitive surgery is required in less than a third. Endoscopic visualisation and assistance is increasingly used for radical resection, where indicated. METHODOLOGY: Our experience of endoscopic surgery for paediatric PRTs from 2002 to 2021 is presented. All patients underwent MRI with contrast. Serum tumour markers were checked. If negative, endoscopic biopsy and endoscopic third ventriculostomy (ETV) were performed; and CSF collected for tumour markers and abnormal cells. For radical surgery, endoscope-assisted microsurgery procedures were performed to minimise retraction, visualise the extent of resection and confirm haemostasis. RESULTS: M:F ratio was 2:1. The median age of presentation was 11 years. Raised ICP (88.88%) was the commonest mode of presentation. Nineteen patients had pineal tumours, one had a suprasellar and pineal tumour, one had disseminated disease, while six had tectal tumours. The ETB diagnosis rate was 95.45%, accuracy rate was 83.3% and ETV success rate was 86.96%. CONCLUSION: Neuroendoscopy has revolutionised the management of paediatric PRTs. It is a safe and effective procedure with good diagnostic yield and allows successful concurrent CSF diversion, thereby avoiding major surgeries and shunt implantation. It is also helpful in radical resection of lesions, where indicated.

Endoscope-assisted microsurgical clipping and reduction of post-clipping cerebral infarction: historical comparison using diffusion-weighted images.

Endoscopic assistance for aneurysm clipping and its possible benefits have been suggested in previous studies, but its clinical significance has not been fully elucidated. This study aimed to present the efficacy of endoscopy-assisted clipping in reducing post-clipping cerebral infarction (PCI) and clinical outcomes via a historical comparison of patients in our institution from January 2020 to March 2022. A total of 348 patients were included, 189 of whom underwent endoscope-assisted clipping. The overall incidence of PCI was 10.9% (n = 38); it was 15.7% (n = 25) before applying endoscopic assistance and decreased to 6.9% (n = 13) after endoscope application (p = 0.010). The application of a temporary clip (odds ratio [OR]: 2.673, 95% confidence interval [CI]: 1.291-5.536), history of hypertension (OR: 2.176, 95% CI: 0.897-5.279), history of diabetes mellitus (OR: 2.530, 95% CI: 1.079-5.932), and current smoker (OR: 3.553, 95% CI: 1.288-9.802) were independent risk factors of PCI, whereas endoscopic assistance was an independent inverse risk factor (OR: 0.387, 95% CI: 0.182-0.823). Compared to the location of the unruptured intracranial aneurysms, internal carotid artery aneurysms showed a significant decrease in the incidence of PCI (5.8% vs. 22.9%, p = 0.019). In terms of clinical outcomes, PCI was a significant risk factor for longer admission duration, intensive care unit stay, and poor clinical outcomes. However, endoscopic assistance itself was not a significant risk factor for clinical outcomes on the 45-day modified Rankin Scale. In this study, we noted the clinical significance of endoscope-assisted clipping in preventing PCI. These findings could reduce the incidence of PCI and improve the understanding of its mechanisms of action. However, a larger and longer-term study is required to evaluate the benefits of endoscopy on clinical outcomes.

Surgical management of cerebellopontine angle epidermoid cysts: an institutional experience of 10 years.

BACKGROUND: Cerebellopontine angle (CPA) epidermoids, although of benign nature, are of considerable neurosurgical interest because of their close proximity and adherence to the cranial nerves and brain stem. In this paper, we describe our experience and attempt to correlate the final outcomes with the extent of surgical removal. The main objectives were to study various modes of surgical management of CPA epidermoids with regard to removal and preservation of the cranial nerves and also to evaluate the role of endoscopic assisted microsurgical excision thereby minimizing recurrences. This case series is one of the largest series reported so far worldwide. MATERIALS AND METHODS: From 2006 to 2016, 139 patients with CPA epidermoids were operated at Grant Medical College and J. J. Hospital, Mumbai. All patients underwent detailed magnetic resonance imaging (MRI) of brain. Lesions were classified according Rogelio Revuelta-Gutiérrez et al. with respect to their anatomic extent: grade I- within the boundaries of the CPA, grade II- extension to the suprasellar and perimesencephalic cisterns, and grade III-parasellar and temporomesial region involvement. Retrosigmoidal and sub temporal approaches were taken to excise the lesions. Endoscopic assisted microsurgical excision was done in cases with extensions beyond the CPA. Patient follow-up was based on outpatient repeated brain MRI studies. RESULTS: The mean duration of symptoms before surgery was 42 months (range, 2 months to 6 years). The mean follow-up period was 27 months (range, 2-60 months). The main presenting sympt om was headache in 69% (96/139) of the cases and trigeminal neuralgia in 30% cases was the second most common cause of consultation. Seventy-five percent of patients had some degree of cranial nerve (CN) involvement. Retrosigmoid approach was taken in 92% patients and 7 patients with supratentorial extension were operated by combined retrosigmoidal and subtemporal approach. Endoscopic assisted microsurgical excision was done in 40% cases. Use of angled views by an endoscope helped to excise residual tumor in 47 (83%) patients. Complete excision was achieved in 67% of cases. In 33% patients, small capsular remnants could not be removed completely because of their adherence to vessels, brainstem and cranial nerves. Compared with their preoperative clinical status, 74% improved and 20% had persistent cranial nerve deficits in the first year of follow up. CONCLUSIONS: Epidermoid cysts are challenging entities in current neurosurgery practice due to tumor adhesions to neurovascular structures. Meticulous surgical technique with the aid of neurophysiological monitoring is crucial to achieve safe and effective total or subtotal removal of these lesions. A conservative approach is indicated for patients in whom the fragments of capsule is adhered closely to blood vessels, nerves, or the brainstem, in order to avoid risk of serious neurological deficits related to an inadvertent damage of these structures. Use of angled views by endoscope at the conclusion of the surgery may assure the surgeon of total removal of the tumor.

Treatment of middle aortic syndrome with thoraco-abdominal aortic bypass grafting assisted by endoscope in adult.

Middle aortic syndrome (MAS) is a rare disease characterized by distal thoracic aorta or abdominal aorta coarctation, and thoraco-abdominal aortic bypass grafting is an effective treatment for this condition. However, significant trauma is associated with the conventional surgical approach. We report a 26-year-old woman with MAS who presented with hypertension and needed thoraco-abdominal bypass grafting. In this operation, we adopted the endoscopic technique to improve the conventional surgical approach (reduce the incision). This case report shows that it is safe and feasible to use an endoscopic technique to reduce the trauma during this kind of operation, and provides a reference for similar treatments.

Comparison of postoperative cytokine and hormone between endoscopically assisted and open parotid tumor resection.

OBJECTIVE: Endoscopically assisted extracapsular dissection through a single incision along the cephaloauricular furrow has been adapted as a method of access for operating on benign parotid gland tumors. However, no study has compared the immune and stress responses after surgery between the endoscopic procedure and conventional open surgery. METHODS: Through a randomized method, 50 patients with benign parotid gland tumors were assigned to undergo either endoscopically assisted extracapsular dissection or open parotidectomy. The postoperative inflammatory changes and hormonal response in the patients were analyzed at serum level during the preoperative period and at 12, 24, and 72 hr after either surgery. RESULTS: Twenty-three patients received an endoscopic procedure, while 27 underwent open surgery. The size of the incision, amount of intraoperative bleeding, volume of drainage, postoperative pain score, and satisfaction with appearance were all improved in the endoscopic procedure group. Additionally, the serum levels of C-reactive protein, interleukin (IL)-6, IL-10, and cortisol were significantly lower in the endoscopy group in comparison with those in the open surgery group. CONCLUSION: Endoscopically assisted extracapsular dissection on patients with benign parotid gland tumors is associated with lower inflammatory changes and hormone responses than open surgery, thereby reducing perioperative pathophysiological disturbance and enhancing recovery after surgery.

Benefits of endoscope-assisted microsurgery in the management of pediatric brain tumors.

OBJECTIVE: Microsurgical and endoscopic techniques are vastly utilized in brain tumor surgery. Combining both techniques in the same procedure has different forms and applications. The aim of this work was to discuss the usefulness and describe the technical benefits of endoscope-assisted microsurgery (EAMS) in treating pediatric brain tumors in various anatomical locations. METHODS: The medical records of 106 children who had undergone EAMS for brain tumors at Children's Cancer Hospital Egypt (CCHE-57357) between January 2009 and January 2017 were reviewed. The patients' ages ranged from 1 to 16 years (mean age 7.5 years). Technical variations, difficulties, complications, strategies, and extent of resection were addressed according to anatomical location. RESULTS: In general, EAMS enabled closer inspection of tumor extension and surrounding vital structures, especially in the hidden corners not appreciable by the microscope alone, such as tumors in the internal auditory canal and cerebellopontine angle contents in 14 cases, all of which were totally excised, and the undersurface of the optic apparatus in 65 craniopharyngiomas. Total excision was achievable in 51 of the 65 craniopharyngiomas; residual tumor was intentionally left behind under endoscopic guidance in the remaining 14 patients to ensure better hypothalamic function. Vision improved in 15 of 16 patients who initially presented with visual defects. Only 4 patients had new-onset postoperative endocrinopathies. For intraventricular tumors, EAMS allowed earlier recognition of tumor pedicle and, hence, earlier control of the blood supply of the tumor and safer total excision of 12 lateral ventricle, 6 pineal and third ventricle, and 9 fourth ventricle tumors. The tandem use of the endoscope and microscope enabled safer tumor dissections that were performed with more confidence in situations in which pure microscopic excision was either not achievable or less safe. Technical strategies, pitfalls, difficulties, and precautions were categorized and described per tumor location. CONCLUSIONS: EAMS of pediatric brain tumors is a promising, user-friendly tool that complements microsurgery in the management of these complex lesions. The benefits of 2D endoscopy are added to the benefits of stereoscopic perception. EAMS is especially helpful during the removal of different complex pediatric brain tumors. Simultaneous or tandem endoscopic and microscopic approaches may have the potential for better functional outcomes through better visualization and preservation of vital structures in corners that are hidden from the microscope.

Endoscope-assisted microsurgical evacuation versus external ventricular drainage for the treatment of cast intraventricular hemorrhage: results of a comparative series.

Cast intraventricular hemorrhage (IVH) is associated to high morbidity/mortality rates. External ventricular drainage (EVD), the most common treatment adopted in these patients, may be unsuccessful due to short-term drain obstruction and requires weeks for cerebrospinal fluid (CSF) clearing, increasing the risks of ventriculits. Administration of intraventricular fibrinolytic agents and endoscopic evacuation have been proposed as alternative treatments, but with equally poor results. We present a retrospective analysis of two groups of patients who respectively underwent endoscope-assisted microsurgical evacuation versus EVD for the treatment of cast IVH. In a 10-year time, 25 patients with cast IVH underwent microsurgical, endoscope-assisted evacuation. Twenty-seven were instead treated by EVD. The two groups were compared in terms of hematoma evacuation, CSF clearing time, infection rates, need for permanent shunting, short/long-term survival, and functional outcome. In endoscope-assisted surgeries, full CSF clearance required 14 ± 3 days in 20 patients and 21 ± 3 days in 5; in the EVD group, 21 ± 3 days were needed in 12 patients, 28 ± 3 days in 11, and 35 ± 3 days in 4. Permanent shunting was inserted respectively in 19 endoscopic and 23 EVD patients. Final mRs score was 0-3 in 13 endoscopic cases, 4-5 in the remaining 12. In the EVD group, 7 subjects scored mRs 0-3, 16 scored 4-5; 4 died. In our experience, endoscope-assisted evacuation of cast IVH reduced ICU staying and CSF clearance times. It also seemed to improve neurological outcome, but without affecting the need for permanent shunt. On the counterside, it increases the number of severely disabled survivors.

Arachnoid bands and venous compression as rare causes of hemifacial spasm: analysis of etiology in 353 patients.

BACKGROUND: Hemifacial spasm is usually caused by arterial compression at the root exit zone of the facial nerve. However, other etiologies have been reported. The aim of this study was to analyze the frequency of other causes of hemifacial spasm. METHODS: Our prospectively maintained hemifacial spasm database containing all patients who underwent microvascular decompression (MVD) for hemifacial spasm from 2002 to 2018 was reviewed. All offending structures were identified and recorded by the surgeon at the time of surgery. Additionally, the operative videos were analyzed retrospectively. RESULTS: MVD was performed in 353 patients. Arterial compression was the main cause of hemifacial spasm in 341 (96.9%) patients. Combined venous-arterial compression was seen in 7 (2.0%) patients. In one patient, the compression was from a large vein. In two patients, no compression was found. One patient who suffered from Bell's palsy many years previously had severe synkinesis and the other had facial tics. In two patients, the spasm was caused due to strangulation of the facial nerve by arachnoid bands. Long-term follow-up of more than 18 months was available in 249 patients with total resolution or near total resolution of spasms in 89.96% of patients. CONCLUSIONS: In most patients with hemifacial spasm, arterial vessels are involved in compressing the facial nerve. Purely venous compression is rarely encountered. We report for the very first time arachnoid bands strangulating the nerve as a cause for hemifacial spasm without involvement of any vessel.

Hybrid antero-lateral transcondylar approach to the clivus: a laboratory investigation and case illustration.

BACKGROUND: Surgical treatment of lesions involving the ventral craniovertebral junction (CVJ) and the lower clivus, traditionally involved complex lateral or transoral approaches to the skull base. However, mid or upper clivus involvement requires more extensive lateral approaches. Recently, the endoscopic endonasal approach (EEA) has become the standard for upper CVJ lesions and medial clival, and a valuable alternative for those tumors extending in its upper third as well as laterally. However, the EEA is associated with an increased risk of post-operative CSF leakage and infection when the tumor is characterized by an intradural extension. Furthermore, whenever the tumor has significant lateral and/or inferior extension below the odontoid process, the chances for a complete resection decrease. METHOD: To analyze the extent of exposure of a hybrid microscopic-endoscopic transcondylar antero-lateral approach to the CVJ and clival region, and to verify its effectiveness in terms of mid and upper clival access. Five silicone-injected cadaver heads were used. Following a standard antero-lateral approach, condylectomy and jugular tubercle drilling were performed, after which angled endoscopes were utilized to extend the bone resection to the clivus. A volumetric assessment of the amount of clival removal was carried out. A case of CVJ chordoma operated through this approach is presented. RESULTS: The hybrid antero-lateral transcondylar approach provides adequate exposure of the ventral CVJ, up to the dorsum sellae and the sphenoid sinus, the contralateral petrous apex, and the contralateral paraclival internal carotid artery (ICA). Approximately 60% of the total clival volume can be removed with this approach. The main limitation is the limited visualization of the ipsilateral paraclival ICA and petrous apex. CONCLUSION: The hybrid antero-lateral transcondylar approach is a valuable surgical option for CVJ tumor extending from C2 to the mid and upper clivus.

Endoscope-Assisted Microneurosurgery for Intracranial Aneurysms: Operative Technique, Reliability, and Feasibility Based on 14 Years of Personal Experience.

Endoscope-assisted microneurosurgery (EAM) combines endoscopic and microsurgical techniques for the treatment of deeply located intracranial lesions. During aneurysm surgery, endoscopic assistance may aid in the visualization of perforating arteries, especially when minimally invasive approaches are used. Between 2002 and 2015, a total of 183 patients with 208 intracranial aneurysms were surgically treated in our department. EAM was performed in 191 procedures. In all, 159 aneurysms were located in the anterior circulation and 49 in the posterior circulation. Of these, 135 aneurysms were ruptured. Lesions were exposed through standard skull base microsurgical approaches. The endoscope was employed during three steps: initial inspection, true operative time, and final inspection. Complications directly related to endoscopic procedures were rare; no surgical mortality was observed in this series. A retrospective analysis of each procedure showed that the usefulness of EAM depended on the anatomical location and size of the lesions. Its advantages were especially evident when dedicated scopes and holders were used.

Local hemostatic matrix for endoscope-assisted removal of intracerebral hemorrhage is safe and effective.

BACKGROUND/PURPOSE: Minimally invasive endoscope-assisted (MIE) evacuation of spontaneous intracerebral hemorrhage (ICH) is simple and effective, but the limited working space may hinder meticulous hemostasis and might lead to rebleeding. Management of intraoperative hemorrhage is therefore a critical issue of this study. This study presents experience in the treatment of patients with various types of ICH by MIE evacuation followed by direct local injection of FloSeal Hemostatic Matrix (Baxter Healthcare Corp, Fremont, CA, USA) for hemostasis. METHODS: The retrospective nonrandomized clinical and radiology-based analysis enrolled 42 patients treated with MIE evacuation of ICH followed by direct local injection of FloSeal Hemostatic Matrix. Rebleeding, morbidity, and mortality were the primary endpoints. The percentage of hematoma evacuated was calculated from the pre- and postoperative brain computed tomography (CT) scans. Extended Glasgow Outcome Scale (GOSE) was evaluated at 6 months postoperatively. RESULTS: Forty-two ICH patients were included in this study, among these, 23 patients were putaminal hemorrhage, 16 were thalamic ICH, and the other three were subcortical type. Surgery-related mortality was 2.4%. The average percentage of hematoma evacuated was 80.8%, and the rebleeding rate was 4.8%. The mean operative time was 102.7 minutes and the average blood loss was 84.9 mL. The mean postoperative GOSE score was 4.55 at 6-months' follow-up. CONCLUSION: This study shows that local application of FloSeal Hemostatic Matrix is safe and effective for hemostasis during MIE evacuation of ICH. In our experience, this shortens the operation time, especially in cases with intraoperative bleeding. A large, prospective, randomized trial is needed to confirm the findings.

The value of lateral spread response monitoring in predicting the clinical outcome after microvascular decompression in hemifacial spasm: a prospective study on 100 patients.

Microvascular decompression represents an effective treatment for hemifacial spasm. The use of lateral spread response (LSR) monitoring remains a useful intraoperative tool to ensure adequate decompression of the facial nerve. The aim of this study was to assess the value of LSRs intraoperative monitoring as a prognostic indicator for the outcome of microvascular decompression in hemifacial spasm. Our study included 100 patients prospectively. The patients were classified into four groups whether LSRs were totally, partially, not relieved, or not detected from the start. According to clinical outcome, the patients were classified into four groups depending on the clinical course after surgery and the residual symptoms if any. Then, correlations were made between LSR events and treatment outcome to detect its reliability as a prognostic indicator. LSRs were relieved totally in 56 % of the patients, partially relieved in 14 %, not relieved in 10 %, and were not detected in 20 % of the patients from the start. HFS was relieved directly after operation in 62 % with clinical improvement of 90-100 %. Thirty-one percent described 50-90 % improvement over the next 3 months after surgery. Almost all of these 31 % (28 out of 31 patients) reported further clinical improvement of 90-100 % within 1 year after surgery. Three percent suffered from a relapse after a HFS-free period, and 4 % reported minimal or no improvement describing 0-50 % of the preoperative state. The percentage of the satisfied patients with the clinical outcome who reported after 1 year a clinical improvement of 90-100 % was 90 %. Statistical analysis did not find a significant correlation between the relief of LSRs and clinical outcome. LSRs may only represent an intraoperative tool to guide for an adequate decompression but failed to represent a reliable prognostic indicator for treatment outcome.

Rigid, Variable-View Endoscope in Neurosurgery: First Intraoperative Experience.

INTRODUCTION: The endoscope became a highly valued visualization tool in neurosurgery. However, technical limitations caused by the rigidity of current standard endoscopes significantly decrease ergonomy in transcranial neurosurgery. Further technological developments will aid enlarging the surgical applicability. OBJECTIVE: To evaluate the intraoperative features of a rigid variable-view endoscope in neurosurgery. METHODS: We assessed a 4 mm rigid rod lens endoscope (EndoCAMeleon, Karl Storz, Tuttlingen, Germany) in the intraoperative setting. The device offers a variable angle of view from 15° to 90° in one plane. The endoscope was used in 3 cases (aneurysm clipping, vestibular schwannoma surgery, endoscopic third ventriculostomy) for inspection. RESULTS: Direct insertion of the device through the craniotomy/burr hole with the lowest angled view (15°) was always possible. Neurovascular structures crossing the access route could be visualized and avoided. This allowed a targeted positioning of the endoscope's tip in the operating field. Once the target point was reached, viewing direction was changed in one plane from 15° to 90° according to anatomic demands. As the endoscope's tip does not move while the lens is rotated, surrounding neurovascular structures are not at risk to be injured. However, turning of the lens-controlling wheel in proximity to delicate structures may be inconvenient. CONCLUSION: The rigid, variable-view endoscope has the potential to become an appreciated visualization tool in neuroendoscopy. The steerable lens enables a tremendous expansion of the visual field, resulting in higher efficiency for surgeons and increased safety for patients.

A comparative study of transcervical, endoscope-assisted transcervical, and endoscope-assisted transoral resection of retrostyloid space schwannomas.

BACKGROUND: The aim of this retrospective study was to compare the efficacy of transcervical (TC), endoscope-assisted transoral (TO), and endoscope-assisted TC for resection of retrostyloid space schwannomas. METHODS: The study included patients who underwent complete resection of schwannomas by only one surgical approach. The data we collected included tumor size, estimated blood loss, postoperative complications, and so on. Statistical analysis was performed using one-way analysis of variance and Fisher's exact test. RESULTS: The study collected 85 patients with tumors mostly located at the oropharyngeal level who were followed up 6 months at least. The results showed that endoscope-assisted TO had certain advantages over others. Additionally, the endoscope-assisted TO set the lowest incidence of neurological complications. CONCLUSION: Our findings demonstrate that for team with rich experience in the skull base surgery, endoscope-assisted TO is a superior option compared to the other two groups for resection of retrostyloid space schwannomas, with the better preservation of neurological function.