Combined endoscopic endonasal transtubercular and transclival approaches for large neurenteric cyst in posterior cranial fossa: A case report and literature review

Background: Intracranial neurenteric cysts (NCs) are extremely rare tumors that more commonly involve the posterior fossa than any other cranial part. While transcranial skull base surgery has been the mainstay of treatment, the utility of endoscopic transnasal surgery (ETS) remains to be established. Case Description: We report a case of a large posterior fossa NC extensively involving the suprasellar region, cerebellopontine angle, and prepontine cistern, which we successfully resected with ETS through a combination of transtubercular and transclival routes. Before surgery, the patient presented with abducens nerve and pseudobulbar palsies, which resolved within 2 weeks postoperatively. The patient remained free from recurrence for 3 years postoperatively. Conclusion: Extended ETS may offer a minimally invasive option for the posterior fossa NC, extensively occupying the ventral space of the brainstem.

Development of novel Mixed Reality-Based Simulator for Endoscopic Transnasal Surgery with HoloLens and multiple AR tracker

Background Virtual reality (VR) and mixed reality (MR) are now widely applied for preoperative simulation and intraoperative navigation. Methods We developed an MR-based simulator for endoscopic transnasal surgery (ETNS) with a head-mounted display HoloLens and evaluated its usefulness. This simulator consisted of MR images of patients and an MR endoscope. HoloLens was used for projection of MR images and recognition of markers. The MR images were reconstructed from the preoperative images of patients and superimposed onto the endoscopic training model of the head. The MR endoscope was superimposed onto a three-dimensional (3D) printed replica of an endoscope. The MR endoscopic images from the replica of the endoscope were projected in the operator’s visual field. The MR images followed the manipulation of the replica of the endoscope through a nasal cavity on the training model. To evaluate the developed simulator, the MR endoscopic images were compared with video-recorded actual operative endoscopic views. And face validity and content validity of the simulator were evaluated by senior residents, using a 5-point Likert scale. Result The 3D MR images through HoloLens correlated well with the actual intraoperative views. Although there was an innate learning curve with the simulator, the face validity and the content validity demonstrated effective simulation of an operative field of view with real-time characteristics of the surgical procedure. Conclusions Our developed simulator for ETNS will contribute to learning the unique and the limited surgical fields through the narrow surgical corridor with endoscope, particularly for novice surgeons.

Aerosolization risk during endoscopic transnasal surgery: a prospective qualitative and quantitative microscopic analysis of particles spreading in the operating room

OBJECTIVE The coronavirus disease 2019 (COVID-19) pandemic represents the greatest public health emergency of this century. The primary mode of viral transmission is droplet transmission through direct contact with large droplets generated during breathing, talking, coughing, and sneezing. However, the virus can also demonstrate airborne transmission through smaller droplets (< 5 μm in diameter) generated during various medical procedures, collectively termed aerosol-generating procedures. The aim of this study was to analyze droplet contamination of healthcare workers and splatter patterns in the operating theater that resulted from endoscopic transnasal procedures in noninfected patients. METHODS A prospective nonrandomized microscopic evaluation of contaminants generated during 10 endoscopic transnasal procedures performed from May 14 to June 11, 2020, in the same operating theater was carried out. A dilution of monosodium fluorescein, repeatedly instilled through nasal irrigation, was used as a marker of contaminants generated during surgical procedures. Contaminants were collected on detectors worn by healthcare workers and placed in standard points in the operating theater. Analysis of number, dimensions, and characteristics of contaminants was carried out with fluorescence microscopy. RESULTS A total of 70 samples collected from 10 surgical procedures were analyzed. Liquid droplets and solid-tissue fragments were identified as contaminants on all detectors analyzed. All healthcare workers appeared to have been exposed to a significant number of contaminants. A significant degree of contamination was observed in every site of the operating room. The mean (range) diameter of liquid droplets was 4.1 (1.0–26.6) μm and that of solid fragments was 23.6 (3.5–263.3) μm. CONCLUSIONS Endoscopic endonasal surgery is associated with the generation of large amounts of contaminants, some of which measure less than 5 μm. All healthcare workers in the surgical room are exposed to a significant and similar risk of contamination; therefore, adequate personal protective equipment should be employed when performing endoscopic endonasal surgical procedures.

A single-center experience with giant cell tumors of sphenoid bone and clivus

Objective: To present pathologic, clinical, and treatment findings for giant cell tumors (GCTs) of sphenoid bone and clivus. Methods: We describe the optimal treatment algorithm in patients with a histopathologic diagnosis of bone GCT by presenting the effects of denosumab treatment in both pediatric and adult patients with GCT undergoing endoscopic transnasal surgery. Clinicopathologic correlation is crucial for the differential diagnosis of GCT and the choice of treatment modality. Conclusion: GCT of bone is a local aggressive tumor that accounts for about 3%–7% of all bone tumors. GCTs located in the cranium are extremely uncommon neoplasms. There are no defined guidelines for the treatment of GCTs in skull base. Following surgical resection of the tumor, the addition of denosumab treatments to radiotherapy has a significant role in preventing the recurrence of GCT and in promoting regression of residual tumor size.

Endoscopic Two-Port Technique for Orbital Tumors, A Combined Transnasal and Sublabial Approach: A Retrospective Case Study

Background: We investigated the indications for a combined endoscopic transnasal and sublabial transantral approach for the surgical treatment of orbital lesions. Methods: This case study enrolled 10 patients scheduled for endoscopic transnasal surgery for treating orbital lesions from 2009 to 2020. When the tumor was localized to the medial part of the orbit, patients underwent endoscopy with a transnasal mononostril approach. Alternatively, when the tumor was localized to the mediocaudal part of the orbit, and when instrument maneuverability was limited, the transnasal approach was combined with a sublabial transantral approach. This two-port surgery approach was preferred over a trans-septal approach (binostril approach), because the two-port approach could expand the operating field in the medial part of the orbit. Here, we evaluated the indications, complications, and advantages of monoportal and combined two-portal approaches. Results: Among the 10 patients enrolled, 8 (80.0%) underwent surgery with the transnasal mononostril approach, and 2 (20.0%) underwent surgery with the combined transnasal mononostril and sublabial transantral approach. In the two latter cases, visualization of the operation field was excellent, and there was adequate room for manipulating instruments. No dysesthesia in the region of infraorbital nerve was observed postoperatively.Conclusion: The combination mononostril-transantral approach provided the space necessary to maneuver instruments and to visualize the surgical field in treating mediocaudal orbital lesions. This two-portal approach enabled extensive resections of intraconal lesions; thus, it could be considered a suitable alternative to the binostril approach.

Endoscopic Transnasal Resection of Trigeminal Schwannoma

Trigeminal schwannoma is a rare skull base tumor that can be managed in a variety of treatments including image observation, surgery, stereotactic radiosurgery, such as gamma knife radiosurgery (GKS), and combination of these. Endoscopic transnasal resection is very effective when the tumor is not invading far laterally, or the risk of cerebrospinal fluid (CSF) leak is estimated to be low. A 74-year-old man with a history of prostate cancer and diabetes presented with left oculomotor nerve palsy over a month. Magnetic resonance images (MRI) demonstrated a 25-mm mass in the left cavernous sinus protruding to the left orbit via the superior orbital fissure (Fig. 1). The patient underwent endoscopic transnasal surgery to decompress the mass. The surgery was uneventful, and postoperative MRI demonstrated satisfactory subtotal resection of the mass (Fig. 2). The final pathology returned as schwannoma. At 1-year follow-up, the tumor slowly enlarged, and the patient underwent GKS with a marginal dose of 14 Gy. At the last follow-up, 4 months after GKS, the tumor was stable. Unfortunately the patient deceased from the known prostate cancer. Endoscopic transnasal surgery was especially useful in this case, considering the preoperative known cancer state that management of this benign tumor did not ruin the quality of life of this patient while minimizing hospitalization, as achieving satisfactory tumor control with aid from postoperative GKS, minimizing complications.The link to the video can be found at: https://youtu.be/Q0Ugc2VFV4w.

Retrospective Case Analysis of Transnasal Endoscopic Resection of Benign Orbital Apex Tumors: Some Thoughts on Transnasal Endoscopic Surgery

Purpose. To deeply discuss the patient selection, surgical planning, surgical techniques, and the therapeutic challenge for endoscopic transnasal resection of benign orbital apex tumors (OATs). Methods. We retrospectively analyzed the cases of 18 patients (18 eyes) with orbital apex cavernous hemangioma (OACH) who underwent endoscopic transnasal approach for resection of the tumor in Zhongshan Ophthalmic Center from March 2016 to May 2020. At each follow-up visit, the patients underwent measurement of their best-corrected visual acuity (BCVA), slit-lamp examination, indirect ophthalmoscopy, and visual field testing. Results. There were 18 patients, 7 males and 11 females, with a mean age of 49.9 ± 12.6 years (range: 26 to 70 years). All 18 patients had unilateral tumors. Among the 18 cases, 13 were located in the right orbit and 5 were located in the left orbit. Sixteen patients underwent purely endoscopic transnasal surgery, and the other 2 patients underwent an endoscopic transnasal approach combined with a transcutaneous or transconjunctival surgical approach. Fourteen patients’ OACHs were removed completely, 1 patient’s OACH was partly removed, and 3 patients underwent pure decompression of the optic nerve. Fourteen patients gained improved or stable BCVA after surgery. Three patients showed postoperative vision decline, and 1 patient had no light perception after surgery. Conclusions. Endoscopic surgery is an effective surgical technique for the treatment of benign tumors in the orbital apex. It is necessary to strictly select patients and fully evaluate the benefits and risks of tumor completely or partly removed.

A modular, multi-arm concentric tube robot system with application to transnasal surgery for orbital tumors

In the development of telemanipulated surgical robots, a class of continuum robots known as concentric tube robots has drawn particular interest for clinical applications in which space is a major limitation. One such application is transnasal surgery, which is used to access surgical sites in the sinuses and at the skull base. Current techniques for performing these procedures require surgeons to maneuver multiple rigid tools through the narrow confines of the nasal passages, leaving them with limited dexterity at the surgical site. In this article, we present a complete robotic system for transnasal surgery featuring concentric tube manipulators. It illustrates a bagging concept for sterility, and intraoperatively interchangeable instruments that work in conjunction with it, which were developed with operating room workflow compatibility in mind. The system also includes a new modular, portable surgeon console, a variable view-angle endoscope to facilitate surgical field visualization, and custom motor control electronics. Furthermore, we demonstrate elastic instability avoidance for the first time on a physical prototype in a geometrically accurate surgical scenario, which facilitates use of higher curvature tubes than could otherwise be used safely in this application. From a surgical application perspective, this article presents the first robotic approach to removing tumors growing behind the eyes in the orbital apex region, which has not been attempted previously with a surgical robot.