Surgical therapy in advanced sinonasal carcinomas - retrospective study.

BACKGROUND AND AIM: Sinonasal tumors are a rare and heterogeneous group of malignant tumors with different histopathological characteristics and clinical presentation. These tumors are usually treated through surgery. The aim of this study is to present our results of surgical therapy in patients with an advanced sinonasal tumor. METHODS: This retrospective study included patients with an advanced sinonasal tumor who were surgically treated. The surgical technique combined both a frontal transbasal approach together with an endoscopic endonasal approach. The parameters used for evaluation were the histological type of tumor, the radicality of resection (complete vs. incomplete), the frequency of recurrence, the surgical and postoperative complications, the type of subsequent oncological therapy and the overall survival. RESULTS: The group consisted of ten patients seven were men and three were women. Complete resection (defined as R0) was achieved in 8 (80%) of the cases, subcomplete resection was achieved in 2 (20%) of the cases. The overall survival period was 28.7 months (95% confidence interval 15.9-41.6). CONCLUSION: The combination of the frontal transbasal approach with the endoscopic endonasal approach is a suitable surgical strategy that enables easier achievement of complete tumor resection, reconstruction of the anterior skull base and reduces the need for extensive surgical approaches.

Melanoma of the external auditory canal: case report and systematic literature review.

Melanoma of the external auditory canal (EAC) is particularly rare and poorly understood, with limited available data on management and survival. This systematic review aims to analyze existing data and provide insights into the management and prognosis the beginning of EAC melanoma. It is conducted using Pubmed and Scopus databases from the beginning to July 2023 and it follows the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) 2020 guidelines. Searches are performed using the search string "(melanoma) AND (external auditory canal)".The review includes a total of 30 patients diagnosed with EAC melanoma, supplemented by an additional case from the authors' clinical experience. The role of Breslow thickness as a determining factor for the choice of surgery remains inconclusive due to limited available data. Sentinel lymph node biopsy and adjuvant therapy are sparingly employed, indicating the need for standardized guidelines. Patients in the study demonstrate a 50% overall survival rate at 5 years.EAC Melanoma is a rare and aggressive malignancy with limited therapeutic guidelines. Surgical interventions, including wide local excision and lateral temporal bone resection, are the primary treatment options for patients without distant metastases.

Management of recurrent cerebrospinal fluid rhinorrhea caused by sequential, anatomically separated skull base defects - A case-based systematic review.

OBJECTIVE: Recurrent cerebrospinal fluid (CSF) rhinorrhea caused by sequential, anatomically separated skull base defects are rarely reported in the literature. Neither management nor etiology are sufficiently investigated. We herein present an illustrative case and a systematic review of the literature regarding etiology, diagnostics, and management of this rare phenomenon. METHODS: A systematic literature search looking for articles reporting sequential CSF-leaks with multiple skull base defects was performed. Data from included articles was descriptively reported, the quality of the included studies was assessed with GRADE. RESULTS: A 71-year-old female patient with posttraumatic rhino- and left-sided otorrhea due to a left-sided longitudinal fracture of the petrous bone presented at our institution. After initial surgical repair and a ten-week symptom-free interval, CSF-rhinorrhea reoccurred. Imaging review revealed a pre-existing contralateral meningoencephalocele of the lateral sphenoid recess causing recurrent CSF-rhinorrhea most likely after initial traumatic laceration. The defect was successfully treated. Literature search identified 366 reports, six of which were included in the systematic review with a total of ten cases. Quality was deemed good in 8/10 cases. The most common location for primary and sequential CSF-leaks was along the sphenoid bone (4/10 and 5/10 patients, respectively). All publications except one reported the presence of a meningo(encephalo)cele as cause of the sequential CSF-leak. CONCLUSION: Occurrence of recurrent CSF-rhinorrhea due to an anatomically separated sequential skull base lesion remains a rare yet described phenomenon. Reassessment of imaging studies and a structured diagnostic work-up to detect sequential CSF-leaks independent of the primary lesion should therefore be considered.

Innovations in the Treatment of Spinal Cerebrospinal Fluid Leaks.

Spontaneous spinal cerebrospinal fluid (CSF) leaks are uncommon but can be neurologically debilitating. When initial treatments fail, definitive repair or closure of the leak is indicated. Depending upon the type of leak present, innovative strategies for their treatment have been developed. Among them are open surgical techniques using a transdural approach for the closure of ventral CSF leaks, minimally invasive tubular techniques for the reduction and repair of lateral meningeal diverticula, and endovascular embolization of CSF-venous fistulas. Illustrative cases demonstrating the indications for and implementation of these techniques are provided.

Long-term outcomes in advanced anterior skull base malignancy: a single quaternary institution experience.

BACKGROUND: Advanced skull base malignancies are a heterogenous subset of head and neck cancers, and management is often complex. In recent times, there has been a paradigm shift in surgical technique and the advent of novel systemic options. Our goal was to analyse the long-term outcomes of a single quaternary head and neck and skull base service. METHODS: A retrospective review of 127 patients with advanced anterior skull base malignancies that were treated at our institution between 1999 and 2015 was performed. Multiple variables were investigated to assess their significance on 5 and 10-year outcomes. RESULTS: The mean age was 60.9 (± 12.6 SD). Sixty-four percent were males and 36% were females. Ninety percent of patients had T4 disease. Median survival time was 133 months. The 5-year overall survival (OS) was 66.2%, disease-specific survival (DSS) was 74.7%, and recurrence-free survival (RFS) was 65.0%. The 10-year OS was 55.1%, DSS was 72.1%, and RFS was 53.4%. Histological type and margin status significantly affected OS & DSS. CONCLUSION: Surgical management of advanced skull base tumours has evolved over the last few decades at our institution with acceptable survival outcomes and complication rates. Histological diagnosis and margin status are the main predictors of survival. The addition of neoadjuvant systemic agents in current trials may improve outcomes.

Endoscopic Endonasal Reconstruction of Intraoperative Cerebrospinal Fluid Leak in Different Skull base Regions: Outcomes, Meningitis and Risk Factors.

OBJECTIVE: Various non-vascularized or vascularized techniques have been adopted in endoscopic endonasal surgery (EES) for repairing intraoperative cerebrospinal fluid (CSF) leaks after tumor resection. Vascularized nasoseptal flaps (VNSF), free nasoseptal grafts (FNSG), free turbinate grafts (FTG), fascia lata and mashed muscle (FLMM) are frequently used. Outcomes of those grafts applied in the defects of different regions need to be clarified. METHODS: The data from a series of 162 patients with skull base tumor who underwent EES that had intraoperative CSF leak between Jan 2012 and Jan 2021 were retrospectively analyzed. The regions included anterior skull base (ASB), sellar region, clivus and infratemporal fossa (ITF). Repair failure rate (RFR), meningitis rate and associated risk factors were assessed. RESULTS: In total, 172 reconstructions were performed in 162 patients for the four sites of the skull base. There were 7 cases (4.3%) that had postoperative CSF leaks, which required second repair. The RFR for ASB, sellar region, clivus, and ITF was 2.6%, 2.2%, 16.7%, and 0%, respectively. The clivus defect was an independent risk factor for repair failure (P<0.01). The postoperative meningitis rate was 5.6%. Repair failure was an independent risk factor for meningitis (P < 0.01). CONCLUSIONS: VNSF, FNSG, FTG, FLMM are reliable autologous materials for repairing the dural defects in different regions during EES. Clivus reconstruction remains a great challenge, which had a higher RFR and meningitis rate. Repair failure is significantly associated with postoperative meningitis.

Combined Deficit of the Four Lower Cranial Nerves also Known as the Syndrome of Collet-Sicard: A Systematic Review and Meta-analysis.

Combined deficit of the four lower cranial nerves (CN IX, X, XI, and XII) was originally described by French physicians Collet (1915) and Sicard (1917) during World War I. To date though, this rare neurological clinical picture lacks systematic evidence regarding its epidemiology, clinical presentation, treatment strategies, and outcome. We conducted a systematic review and meta-analysis concerning Collet-Sicard syndrome (CSS) on Medline database in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The research yielded 84 articles among which 73 individual case reports were eventually retained. Mean age was 53.7 (± 16) years old and the male-to-female ratio was 1.8/1. CSS was firstly caused by tumors (38.4%), following by vascular etiologies (28.8%), trauma (16.4%), and infection (6.8%), among others. Temporary enteral nutrition was required for 17 patients (23.3%). The four CN presented significant chances of complete or partial recovery: 52.1% for CN IX ( p < 0.001), 46.6% for CN X and CN XII ( p < 0.001), and 39.7% for CN XI ( p = 0.002). Tumoral causes presented significantly lower chances of favorable CN recovery (7.1%) compared to infection (60%), vascular (52.4%), and trauma (41.7%) ( p < 0.001). Older age (> 53 years old) was not associated with a dismal CN prognostic ( p = 0.763). Most patients (71.2%) presented a favorable outcome (Glasgow Outcome Scale score ≥ 4). All the patients who died (6.8%) suffered from skull base tumors. CSS is a rare condition requiring prompt clinical and radiologic diagnostic and multidisciplinary management. Vascular or infectious-related CSS seem to present a rather good prognostic, closely followed by trauma, whereas tumoral-related CSS seem to suffer from a more dismal prognostic.

The Prevalence of the Middle Clinoid Process: A Cross-Sectional Comparative Study in Patients with and without Pathology of the Sella Turcica.

Background The middle clinoid process (MCP), particularly caroticoclinoid ring (CCR) type of the MCP, is an important part of the sphenoid bone for skull base surgery. Previous studies have shown a wide range of MCP prevalence affected by various factors. However, no study has investigated the association between the MCP and the presence of sellar lesions. Objectives The main aim of this study was to evaluate the prevalence of the MCP in the Thai population and factors associated with its presence. Materials and Methods We conducted a cross-sectional study on 400 sides from 200 patients (100 with and 100 without sellar lesions) using cranial computerized tomography scans. Demographic data and MCP characteristics were collected. The association between individual variables and the presence of the MCP was determined by univariate and multivariate analysis. Results The MCP was identified in 168 of 400 sides (42%). Patients with sellar lesions had a significantly lower prevalence of the MCP compared with normal controls (29.5% versus 54.5%, p < 0.001). Of all MCP only 6% were the CCR type. Univariate and multivariate analysis showed that the absence of the sellar lesion was the only factor significantly associated with presence of the MCP (odds ratio: 2.86; 95% confidence interval: 1.90-4.32; p < 0.001). Conclusion The prevalence of the MCP was relatively high in the Thai population, while the prevalence of the CCR was relatively low compared with previous studies. The absence of sellar lesions was the only factor associated with the presence of the MCP.

Neuroanatomical insights into neuro-ophthalmic presentations of skull base meningiomas: Pathways to precision medicine - A meta-analysis.

Background: Skull base meningiomas are intricately related to neuro-ophthalmic functions and have been related to direct influences on both the afferent and efferent visual pathways due to close contacts with crucial neurovascular structures. The present article reviews the neuro-ophthalmic presentations of these tumors, necessitating the need for precise anatomic information for the delivery of customized diagnostic and therapeutic approaches. Methods: A literature review was conducted using PubMed and Scopus, focusing on terms related to skull base meningiomas and their neuro-ophthalmic impacts. The review included recent and seminal articles to assess advances in understanding and managing these tumors from an anatomical perspective. Results: The findings underscore the diversity in neuro-ophthalmic manifestations based on the meningioma's location, affecting visual pathways differently. For instance, meningiomas in the optic nerve sheath typically lead to isolated optic neuropathy and are often managed with radiation therapy. In contrast, those extending from the sphenoid wing require more aggressive approaches like open surgery. This review highlights how the tumor's location dictates the choice of treatment, ranging from conservative management to multidisciplinary surgical interventions. Conclusion: Proper recognition of the sites of skull base meningiomas results in a treatment tailored to provide therapy aimed explicitly at neuro-ophthalmic outcomes related to the site of the tumors. This approach will not only help to treat effectively but also avoid a wide range of complications and, in turn, increase the effectiveness of the treatment results that a patient will receive. Future studies should aim to refine these anatomical insights toward further advancements in modes of treatment.

The Effects of Nasal Septal Deviation on Anterior Skull Base Parameters.

Introduction Functional endoscopic sinus surgery and endoscopic skull base surgery are frequently performed surgeries today. Nasal septal deviation is a common finding and can affect the surgical area. Therefore, it is important to examine the effect of this deviation on other anatomical structures. Objective The aim of the present study was to determine whether there is a relationship between the degree of nasal septal deviation and anterior skull base structures using computed tomography (CT). Methods A total of 312 patients (aged 18 to 65 years old) whose paranasal sinus CT images were available were included in the study. Measurements were obtained on images retrieved from Picture Archiving and Communication System (PACS) and Horos image archive systems in the bone window in the coronal and axial plane. Results The mean age of 312 patients was 33.00 years old (standard deviation [SD] 11.22 years). The presence of septal deviation was not associated with changes in olfactory fossa (OF) depths, Keros degrees, and the angle between the lateral lamella and the cribriform lamella. However, OF depths and Keros degrees on the deviated side of the septum were found to change at a significant level ( p < 0.05). No significant association was observed between the degree of septal deviation and cribriform lamella-lateral lamella angle. Conclusion The study showed significantly increased OF depth and Keros degree on the deviated side of the nasal septum. Performing CT scans before endoscopic sinus surgery and endoscopic skull base surgery is important to increase the chances of a successful surgical outcome and to reduce complications.

Anatomical Measurement as a Reference for Functional Endoscopic Sinus Surgery Based on CT Scans and Dissections.

Introduction Diseases of the paranasal sinuses, nasal cavities, and those related to the skull base can be treated with nasal endoscopic surgery. Anatomical references are essential to safely perform these surgeries. Objective To measure and compare the distance from the posterior wall of the maxillary sinus to the anterior skull base in cadavers and on computed tomography (CT) scans to determine a measurement as an anatomical reference in imaging exams for sinus and anterior skull base surgery. Methods In dissections and CT scans, we took measurements from the most upper and medial point of the posterior wall of the maxillary sinus (point A) to the point where the skull base deflects and the anterior sphenoid wall is formed (Δ 90°; point B), in the right and left nasal cavities. We used 51 cadavers aged ≥ 18 years in the present research. Results The measurements obtained from CT scans and dissections were greater than 1.5 cm in all cadavers, and they were positively correlated. The 1-cm increase in the AB-tomography measurement corresponded to the 1.08-cm increase to the right and 1.07-cm to the left in the AB-dissection measurement. Conclusion The CT measurements may be considered a reliable tool to promote safe and effective access to the paranasal sinuses, matching the distance that should be dissected until the anterior base of the skull.

Subdural hematoma due to skull base bone metastasis of epidermal growth factor receptor mutated non-small cell lung cancer.

Subdural hematoma due to skull base bone metastasis of lung cancer is rare but are oncological emergency, necessitating prompt identification when a headache develops with the progression of the malignancy.

American Rhinologic Society expert practice statement part 2: Postoperative precautions and management principles following endoscopic skull base surgery.

The goal of this American Rhinologic Society expert practice statement (EPS) is to summarize the best available evidence regarding postoperative precautions for patients following endoscopic skull base surgery for intradural pathology. These topics include the administration of postoperative nasal hygiene; patient mobilization and activity level; the resumption of continuous positive airway pressure in patients with obstructive sleep apnea; and the timing and capacity with which a patient may be subjected to barotrauma, such as air travel postoperatively. This EPS was developed following the recommended methodology and approval process as previously outlined. Given the diverse practices and limited agreement on the accepted principles regarding postoperative precautions for patients following skull base surgery, this EPS seeks to summarize the existing literature and provide clinically relevant guidance to bring clarity to these differing practice patterns. Following a modified Delphi approach, four statements were developed, all of which reached consensus. Because of the paucity of literature on these topics, these statements represent a summation of the limited literature and the experts' opinions. These statements and the accompanying evidence are summarized below, along with an assessment of future needs.

SMARCA4 (BRG1)-deficient carcinoma invading the skull base: report of two cases and literature review.

Introduction and importance: SMARCA4 (BRG1)-deficient carcinomas in the head and neck are a rare and highly aggressive group of malignant tumors. They lack typical clinical and imaging features and are often misdiagnosed. Case presentation: The authors report two male patients with a history of smoking. Case 1 presented with nose bleeding as the first symptom, whereas case 2 presented with headache with blurred vision. Preoperative computed tomography (CT) and MRI suggested a highly aggressive malignant tumor of the head and neck with invasion of the skull base. Case 1 could not be operated on because of the large size of the punctured tumor. Case 2 underwent the surgery. The final pathological diagnosis was SMARCA4 (BRG1)-deficient carcinoma. At the 6-month follow-up, case 1 died. After completing the full course of chemotherapy, case 2 reported progressively worsening headaches and hearing loss. Discussion and conclusion: SMARCA4 (BRG1)-deficient carcinoma in the head and neck is a rare and highly aggressive malignant tumor that is advanced at diagnosis, prone to invasion of adjacent structures, difficult to operate on, and has a poor prognosis. CT and MRI play a vital role in evaluating the size and extent of the tumor, invasion of adjacent structures, and distant metastasis. It provides a significant reference for clinical diagnosis and therapeutic decision-making. Different patients of SMARCA4 (BRG1)-deficient carcinoma in the head and neck respond differently to radiotherapy and chemotherapy. Early use of next-generation sequencing (NGS) or immunohistochemistry(IHC) techniques is helpful in guiding treatment planning.

Multidisciplinary Management of an Internal Carotid Artery Aneurysm Near the Skull Base.

Extracranial carotid artery aneurysms (ECAAs) are rare in comparison to the total number of peripheral artery aneurysms. Although there are multiple treatment modalities, no clear guidelines exist for the optimal management of ECAA. We describe a case of a 59-year-old female with an incidental finding of a 2.6 cm right internal carotid artery (ICA) aneurysm on computed tomography (CT) that was eventually excised via transcervical approach followed by end-to-end anastomosis with great saphenous vein (GSV) graft. To our knowledge, this case demonstrates a novel multidisciplinary approach to an ECAA near the skull base involving head and neck surgery (HNS), vascular surgery (VS), and neuro-interventional radiology (NIR).

Cochlear implantation in patients with inner ear schwannomas: a systematic review and meta-analysis of audiological outcomes.

PURPOSE: In patients with inner ear schwannomas (IES), reports on hearing rehabilitation with cochlear implants (CI) have increased over the past decade, most of which are case reports or small case series. The aim of this study is to systematically review the reported hearing results with CI in patients with IES considering the different audiologic outcome measures used in different countries. METHODS: According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline, a search of published literature was conducted. We included patients with IES (primary or with secondary extension from the internal auditory canal (IAC) to the inner ear, sporadic or NF2 related) undergoing cochlear implantation with or without tumour removal. The audiological results were divided into the categories "monosyllables", "disyllables", "multisyllabic words or numbers", and "sentences". RESULTS: Predefined audiological outcome measures were available from 110 patients and 111 ears in 27 reports. The mean recognition scores for monosyllabic words with CI were 55% (SD: 24), for bisyllabic words 61% (SD: 36), for multisyllabic words and numbers 87% (SD: 25), and 71% (SD: 30) for sentences. Results from for multisyllabic words and numbers in general showed a tendency towards a ceiling effect. Possible risk factors for performance below average were higher complexity tumours (inner ear plus IAC/CPA), NF2, CI without tumour removal ("CI through tumour"), and sequential cochlear implantation after tumour removal (staged surgery). CONCLUSION: Hearing loss in patients with inner ear schwannomas can be successfully rehabilitated with CI with above average speech performance in most cases. Cochlear implantation thus represents a valuable option for hearing rehabilitation also in patients with IES while at the same time maintaining the possibility of MRI follow-up. Further studies should investigate possible risk factors for poor performance. Audiological tests and outcome parameters should be reported in detail and ideally be harmonized to allow better comparison between languages.

Soft Tissue Dissection in the Transcondylar Approach: A Modified Layered Technique to Maximize Lateral Access.

Objective While the transcondylar approach is technically challenging, it provides generous ventral and caudal exposure to the craniovertebral junction. This approach requires navigation around multiple eloquent neurovascular structures including the lower cranial nerves, vertebral artery and its branches, and the brainstem. Superficial exposure, including incision location and muscle dissection, can dramatically affect the surgical angle and maneuverability at depth. Methods We demonstrate the transcondylar approach in a step-by-step fashion in a formalin-embalmed, latex-injected cadaver head. Dissection within each layer of the suboccipital muscles was performed. A small cohort with an illustrative case is also included herein. Results The sternocleidomastoid (SCM) muscle was retracted anteriorly; the splenium capitis, semispinalis capitis, and longissimus capitis muscles were disconnected from the superior nuchal line and reflected inferomedially. The suboccipital muscle group was fully exposed. The superior and inferior oblique muscles were disconnected from the transverse process of C1. The superior oblique and the rectus capitis posterior major muscles were then dissected off the inferior nuchal line, and the suboccipital muscle group was retracted inferomedially en bloc . The greater auricular nerve was retracted laterally with the SCM, and the greater occipital nerve was retracted inferomedially with the suboccipital muscle group. Conclusion This technique avoids the obstructive muscle bulk that results from a myocutaneous approach while maximizing deep exposure. Understanding the detailed muscular anatomical relationship with the insertion location and suboccipital nerves is key to complete and safe extracranial dissection. Diligent dissection helps minimize postoperative pain and muscle spasm while optimizing the closure technique.

Frontotemporal Orbitozygomatic Transcavernous Approach: Stepwise Cadaveric Dissection for a Safe Corridor.

Background Advances in skull base surgery have increased the need for a detailed understanding of skull base anatomy and its intrinsic relationship to surrounding structures. This has resulted in an improvement in patient outcomes. The frontotemporal orbitozygomatic (FTOZ) transcavernous approach (TCA) is an excellent option for treating complex lesions involving multiple compartments of the skull base, including the sellar and parasellar, third ventricle, orbit, and petroclival region. Objective This article aimed to provide a detailed cadaveric dissection accompanying a thorough procedure description, including some tips and pitfalls of this technique. Methods Microsurgical dissection was performed in four freshly injected cadaver heads at the Cranial Base Neuroanatomy Laboratory, Cleveland Clinic Florida. The FTOZ TCA was performed on both sides of the four specimens. The advantages and disadvantages were discussed based on the anatomic nuances of this approach. Results The FTOZ TCA represented a wide access to the anterior, middle, and posterior fossa. When combined with an anterior clinoidectomy, it allowed for significant and safe internal carotid artery mobilization. This approach created numerous windows, including opticocarotid, carotid-oculomotor, supratrochlear, infratrochlear, anteromedial, anterolateral, and posteromedial triangles. The only drawback was the length of the dissection and the level of surgical acumen required to perform it. Conclusion Despite its technical difficulty, the FTOZ TCA should be considered for the surgical management of basilar apex aneurysms and tumors surrounding the cavernous sinus, sellar/parasellar, retrochiasmatic, and petroclival region. Continuous training and dedicated time in the skull base laboratory can help achieve the necessary skills required to perform this approach.

Clinical Outcome in Patients with Large Sinonasal Tumors with Intracranial Extension.

Objectives Malignant tumors of the sinonasal cavities with extension to the frontal skull base are rare and challenging pathologies. Combined-approach surgery using a frontobasal craniotomy and endoscopic sinus surgery with reconstruction of the anterior skull base followed by adjuvant radiotherapy is a preferred treatment strategy in selected cases. Morbidity and mortality rates are high in this population. We aim to add our experience to the current literature. Design We performed a retrospective cross-sectional single center study of the long-term clinical outcome in a tertiary university referral hospital in the Netherlands between 2010 and 2021. Descriptive statistics and frequency distributions were performed Participants Patient, tumor, treatment, complications and survival characteristics of eighteen consecutive patients were extracted from the electronic health records. Main Outcome Measures The primary outcome measures are progression free survival, overall survival and complication rate. Results Eighteen consecutive patients were included with a mean age of 61 (SD ± 10) years (range 38-80); ten males and eight females. Gross total resection was achieved in 14 (77%) patients. Eleven (61%) patients underwent local radiotherapy, one (5%) chemotherapy and three (17%) a combination of both. Mean follow-up duration was 49 months (range 3 - 138). Three (17%) patients died in hospital due to post-operative complications. Six (33%) patients died during follow-up due to disease progression. Mean progression-free survival was 47 months (range 0 - 113). Conclusion In conclusion, the overall survival was 50% for this group of patients with large sinonasal tumors. Progressive disease affects survival rate severely. Surgical complications were seen in five (28%) patients. Radiotherapy is associated with high complication rates. Radiation necrosis was a serious complication in two patients and could be treated with high dose steroids.

Multiportal Retrograde Endoscopy to Enhance Surgical Target Visualization: A Pilot Study.

Objective Current transnasal endoscopic techniques for sinus and skull base surgery use a single endoscope to provide visualization from one perspective curtailing depth perception and compromising visualization of the instrument-target interface. The view can be blocked by instruments, and collisions between instruments often occur. The objective of this study was to investigate the use of multiportal retrograde endoscopy to provide more accurate manipulation of the surgical target. Design Maxillary antrostomy and frontal sinusotomy were performed on three different cadavers by three different surgeons. A zero-degree rigid endoscope was introduced through the nose for the standard transnasal approach. A flexible endoscope was introduced transorally, directed past the palate superiorly, and then flexed 180 degrees for the retrograde view. Videos of the standard transnasal view from the rigid endoscope and retrograde view from the flexible endoscope were recorded simultaneously. Results All surgeries were able to be performed with dual-screen viewing of the standard and retrograde view. The surgeons noted that they utilized the retrograde view to adjust the location of ends/tips of their instruments. Four surgeons reviewed the videos and individually agreed that the visualization achieved provided a perspective otherwise not attainable with rigid transnasal endoscopy alone. Conclusion High-quality visualization of surgical targets such as the frontal or maxillary ostia can be challenging with rigid endoscopes alone. Multiportal retrograde endoscopy provides proof of concept that additional views of a surgical target can be achieved. Additional work is needed to further develop indications, techniques, and generalizability to targets beyond those investigated here.