Skull Base Procedures Research Articles

Feasibility of robotic posterior fossa skull base surgery

OBJECTIVE Despite its potential advantages, robotic surgery has yet to be applied to skull base procedures. Complex anatomy and restricted access have limited the development of robotic skull base surgery. The authors’ aim was to conduct a feasibility study of robotic surgery for posterior fossa skull base lesions. METHODS Six silicone-injected postmortem human heads were prepared for the robotic surgery. Because there was no drilling tool with the robot, specimens were dissected in advance using an endoscope and microscope. The following approaches were investigated: 1) supracerebellar-infratentorial; 2) retromastoid; and 3) posterior occipitocervical junction surgeries. For each approach specific anatomical landmarks were identified, and the surgical freedom (vertical distance angle between the tools) was measured. RESULTS In the case of the supracerebellar-infratentorial approach, the authors used 3 burrs with 1.5 cm of diameter: 1 paramedian and 2 laterally. The view of the pineal region was visualized, and sufficient surgical freedom of both tools was secured. The median vertical distance was 1.2 cm (range 1.1–1.8 cm), and the median angle between the tools was 105° (range 92°–110°). On the other hand, in the retromastoid approach, with a single burr 2.5 cm in diameter, the root exit zone of the facial nerve was barely visible, and a space for tools to access was not secured. The median vertical distance was 0.8 cm (range 0.6–1.0 cm), and the median angle between the tools was 10° (range 6°–12°). In the case of the posterior occipitocervical junction approach, the authors used the 3 tubular retractors, 1 in the middle and 2 laterally. Even though the space was narrow, the medulla and adjacent nerves could be identified, and a moderate level of surgical freedom could be obtained for tool mobilization. The median vertical distance was 1.6 cm (range 1.2–2.5 cm), and the median angle between the tools was 90° (range 88°–95°). CONCLUSIONS Although robotic surgery has yet to be applied to neurosurgery, it is expected to be helpful in posterior fossa skull base surgery if appropriate tools can be developed.

Assessment of Vidian canal morphology in axial section and its associated structures using cone beam computed tomography: A descriptive study

The Vidian Nerve (VN), a branch of the trigeminal nerve, passes by the Vidian Canal (VC), located at the base of the skull. The VC branches into the greater petrosal nerve and the VN in the pterygopalatine fossa, where the greater petrosal nerve carries parasympathetic fibers to the lacrimal glands and nasal mucosa, and the VN carries sensory fibers from the nasopharynx, nasal cavity, and palate. In this study, 60 subjects of both sexes who underwent cone beam computed tomography (CBCT) were selected by a convenient sampling technique. The data were subjected to statistical analysis following the examination of the various parameters in the axial sections. Among the various morphological characteristics appraised in the axial section, there was no significant sexual dimorphism, except for the angle between the VC and the medial wall of the maxillary sinus, which shows statistical significance. The present study aims to investigate morphometric analysis and its associated structures, offering insightful information about the complex structure of the Vidian canal (VC), which provides adequate knowledge for surgeons to plan with more caution complex skull base procedures, and eventually to lower the therapeutical risks associated with it.

Observations from the first 100 cases of intraoperative MRI – experiences, trends and short-term outcomes

BackgroundWe sought to analyze, in well-defined clinical setting, the first 100 patients treated at the intraoperative MRI (iMRI) hybrid surgical theatre at our facility in a population-based setting to evaluate which pathologies are best approached with iMRI assisted surgeries, as this is not yet clearly defined.MethodsPatients undergoing surgery in the 3T iMRI hybrid surgical theatre at our neurosurgical department between December 2017 to May 2021 were included after informed consent. Demographic, clinical, surgical, histological, radiological and outcome parameters, as well as variables related to iMRI, were retrospectively collected and analyzed. Patients were subdivided into adult and pediatric cohorts.ResultsVarious neurosurgical procedures were performed; resection of tumors and epileptic foci, endoscopic skull base procedures including pituitary lesions, deep brain stimulation (DBS) and laser interstitial thermal therapy (LITT). In total, 41 patients were pediatric. An iMRI scan was carried out in 96% of cases and led to continuation of surgery in 50% of cases, mainly due to visualized remaining pathological tissue (95.2%). Median time to iMRI from intubation was 280 min and median total duration of surgery was 445 min. The majority of patients experienced no postoperative complications (70%), 13 patients suffered permanent postoperative deficits, predominantly visual.ConclusionHerein, we demonstrate the first 100 patients undergoing neurosurgery aided by iMRI at our facility since introduction. Indications for surgery differed between pediatric and adult patients. The iMRI was utilized for tumor surgeries, particularly adult low-grade gliomas and pediatric tumors, as well as for epilepsy surgery and DBS. In this heterogenous population, iMRI led to continuation of surgery in 50%. To establish the benefit in maximizing the extent of resection in these brain pathologies future studies are recommended.Clinical trial numberNot applicable.

Pilot Program in Surgical Anatomy Education for Complex Cranial and Skull Base Procedures: Curriculum Overview and Initial 2-Year Experience at Mayo Clinic

Abstract Background Cadaveric dissection remains a preferred and irreplaceable learning modality among neurosurgery residents. We aimed to develop and describe a tiered, quantifiable, and practical curriculum for cranial neurosurgical anatomy education. We report the structure and evaluation of our 2-year pilot study to serve as a suggested guide for other neurosurgery programs. Methods Our Complex Cranial Dissection Program is tailored to the needs of junior-level neurosurgery residents based on their postgraduation years 1 to 4. Dissections are performed in a sequential manner, each of which emphasize a particular set of manual skills and neuroanatomical knowledge. Dissections are scored on a scale of 10 points. The grading was based on specific landmarks and anatomical structures, which need to be exposed, explored, and preserved. Results Out of 16 residents, 14 individuals (87.5%) attended the dissections in the first iteration of the program and 16 individuals (100%) attended the dissections in the second iteration. A total of 17 dissections were performed across all years. In survey feedback about the program, 100% (Year 1) and 94% (Year 2) of residents considered the assigned dissections to be appropriate for their respective training levels. Further, 100% (Year 1) and 94% (Year 2) of residents endorsed that the dissections were important and helpful for their practice prior to similar operating room experiences. Conclusion The development and implementation of structured dissection programs within residency training, along with dedicated staff, and objective feedback serve a crucial role in neurosurgical education to further develop and enhance surgical skills in the operative setting.

The effect of SARS-CoV-2 on the incidence of post-operative venous sinus thrombosis following skull base procedures.

Sinus thrombosis is a common post-operative finding after posterior fossa surgery performed in the vicinity of the dural venous sinuses. The SARS-CoV-2 virus has been shown to confer an increased risk of venous thromboembolic events owing to eliciting a hyper-inflammatory and pro-thrombotic state. In this study, we examine the incidence of post-operative venous sinus thrombosis in patients undergoing peri-sigmoid posterior fossa surgery in the pre- and post-COVID era and investigate whether COVID infection confers an increased risk of sinus thrombosis. A retrospective review of a single institution case series of patients underwent peri-sigmoid surgery (retrosigmoid, translabyrinthine, or far lateral) approach. Relevant clinical variables were investigated that may confer an increased risk of sinus thrombosis. A total of 311 patients (178 in the pre-COVID era, and 133 operated on after the pandemic began in March 2020) are included in the study. The composite incidence of sinus thrombosis seen on post-operative imaging was 7.8%. The incidence of sinus thrombosis in the pre-COVID cohort was N = 12 patients (6.7%) versus N = 12 (9%) in the post-COVID cohort (p = 0.46). A history of COVID infection was not shown to confer an increased risk of post-operative sinus thrombosis (OR: 0.61; 95% CI: 0.08-4.79, p = 0.64). Only a small number of patients (N = 7, 2.3%) required either medical or surgical intervention for post-operative sinus thrombosis. The overall incidence of post-operative sinus thrombosis is similar in the pre- and post-COVID era. The findings of this study suggest that COVID infection is not associated with a higher risk of venous sinus thrombosis.

Endoscopic endonasal anterior skull base surgery : Presentation of a monocentric entity profile

Extended endoscopic endonasal surgery (EEES) is an essential part of treatment of various pathologies of the anterior skull base. In addition to significant improvements in the quality of life of affected patients and alower complication profile compared to open skull base surgery, the therapeutic results are comparable if the indications are correct. Data of all endoscopic endonasal skull base procedures performed at the University Skull Base Center Hamburg under the direction of the Department of Otorhinolaryngology between June 2018 and November 2022 were retrospectively collected. Atotal of 50cases were identified. Of these, 56% (28/50) were malignant tumors, 24% (12/50) were benign pathologies with direct skull base involvement, and 20% (10/50) were anterior skull base defects with rhinoliquorrhea. In 96% (48/50) of cases, the preoperatively set goal of surgery (representative biopsy, complete resection, closure of the skull base defect) could be achieved. Complications gradeIII or higher according to Clavien-Dindo occurred in 4/50cases. During the observation period, n = 5 olfactory neuroblastomas were diagnosed, all of which were exclusively and successfully operated on endoscopically. In recent years, the spectrum of endoscopically resectable pathologies of the anterior skull base has steadily expanded. In particular, midline-related tumors such as olfactory neuroblastoma or iatrogenic/idiopathic skull base defects with cerebrospinal fluid rhinorrhea are treated completely endoscopically with very good results. Nevertheless, there are also limitations to this technique. Due to high variance in the scope of frontobasal surgery, the extent, and the complex anatomy, as well as the overlapping responsibilities of the specialist disciplines, establishment of certified skull base centers and bundling of frontobasal surgery at these centers is highly relevant for quality assurance.

Initial Experience With Robotic-Assisted Otologic and Lateral Skull Base Surgery.

Robotic-assisted surgery has gained popularity for otolaryngology procedures. It provides high-definition images and surgical precision to perform diverse procedures. It is an alternative to the operating microscope, endoscope, or exoscope when reaching hidden anatomical structures in the ear. In this proof-of-concept study, we aim to demonstrate the possibility of using a robotic-assisted device to perform ear surgery in conjunction with the microscope or the endoscope. In total, there were 9 ear and lateral skull base procedures performed with the use of robotic-assisted surgery. All surgeons underwent surveys to assess the performance and workload of the device compared to the microscope or endoscope. There were no postoperative complications. Robotic-assisted surgery was optimal for providing high image quality, ergonomics, and maintaining surgical performance. The size of the device and mental demand were higher compared to the microscope or endoscope. Robotic-assisted surgery can be an adjuvant to perform otologic and neurotologic surgery.

Postoperative Cerebrospinal Fluid-Related Complications After Posterior Fossa and Posterolateral Skull Base Surgeries: Development of a Predictive Model and Clinical Risk Score

ObjectivePostoperative pseudomeningocele (PMC) and cerebrospinal fluid (CSF) leak are common complications following posterior fossa and posterolateral skull base surgeries. We sought to (1) determine the rate of CSF-related complications and (2) develop a perioperative model and risk score to identify the highest-risk patients for these events. MethodsThis was a retrospective cohort of 450 patients undergoing posterior fossa and posterolateral skull base procedures from 2016-2020. Logistic regressions were performed for predictor selection on three pre-specified models: (1) a priori variables, (2) predictors selected by large effect sizes, and (3) predictors with p-value ≤ 0.100 on univariable analysis. A final model was created via elimination of nonsignificant predictors, and the integer-based Post-Operative CSF-related Complications (POCC) clinical risk score was derived. Internal validation was done using 10-fold cross-validation (cv) and bootstrapping with uniform shrinkage. Results115 (25.6%) patients developed PMC/CSF leak. Age > 55 (OR 0.560 [95% CI 0.328-0.954]), BMI > 30 (OR 1.88 [95% CI 1.14-3.10]), and postoperative CSF diversion (OR 2.85 [95% CI 1.64-5.00]) were associated with CSF leak/PMC. Model 2 was the most predictive (cvAUROC 0.690). The final risk score was devised using age, BMI class, dural repair technique, use of bone substitute, and duration of postoperative CSF diversion. The POCC Score performed well (cvAUROC 0.761) and was highly specific (96.1%). ConclusionsWe have created the first generalizable and predictive risk score to identify at risk patients for CSF-related complications. The POCC Score may improve surveillance, inform doctor-patient discussions regarding risks of surgery, and assist in perioperative management.

Complications After Open Skull Base Surgery for Brain Tumors: A 26-Year Experience.

Open skull base surgery carries the risk of significant complications. It is important to inform patients and family members clearly of the details of these complications. This study aimed to present the numerous complications encountered with open skull base surgery for brain tumors. This report analyzed the complications experienced by patients treated with open skull base surgery by a single skull base surgeon at a single tertiary center over 26 years. A retrospective study was performed using the University of Puerto Rico Neurosurgery database to identify patients who were managed using open skull base procedures from 1995 to 2020. The neurosurgical database for each patient had been prospectively recorded. Patients with skull basetumors under the author's care during the study period were includedin the investigation. Exclusions include patients with non-tumoral conditions and non-skull base tumors and those operated using a microscopic transsphenoidal route. Patients who experienced an intraoperative or postoperative complication within 30 days of the surgery were further analyzed. In the cohort, 141 patients with brain tumors underwent open skull base surgery. The cohort had a median age of 48 (range 3-79). It consisted of 101 (71.6%) females and 40 (28.4%) males, with a female-to-male ratio of 2.5:1. The approach most frequently used was an orbitofrontal craniotomy (with or without zygomatic osteotomy) in 79 patients (56%). A petrosal approach was utilized in 26 patients (18%). Forty-six patients (33%) developed an intraoperative or postoperative complication. Twenty-four percent of the complications occurred in the 30-day postoperative period. Five patients had more than one complication. The median age of the patients who experienced a complication was 44.5 (range 22-79), with a female-to-male ratio similar to the entire cohort. Cranial nerve injury was the most frequent complication. Worsening or loss of vision in the affected eye occurred in 5.7% of the patients. A cerebrospinal fluid leak occurred in 2% of the patients. Six patients died, two of them after a massive myocardial infarction. The results of this study showed that approximately one-third of the patients undergoing open skull base surgery can develop a complication. The most frequent complication was injury to a cranial nerve. A large number of complications occurred intraoperatively. The majority of the complications in patients with tumors in the posterior fossa were associated with injury to a cranial nerve. At the middle fossa, damage to the optic nerves is a noteworthy complication. Complications at the anterior fossainvolved worsening of vision ormyocardial infarction. Less aggressive surgery near the cavernous sinus and the petroclival region may reduce complications. Understanding the complications can help counsel patients and family members.

Temporal trends in neurosurgical volume and length of stay in a public healthcare system: A decade in review with a focus on the COVID-19 pandemic.

Over the past decade, neurosurgical interventions have experienced changes in operative frequency and postoperative length of stay (LOS), with the recent COVID-19 pandemic significantly impacting these metrics. Evaluating these trends in a tertiary National Health Service center provides insights into the impact of surgical practices and health policy on LOS and is essential for optimizing healthcare management decisions. This was a single tertiary center retrospective case series analysis of neurosurgical procedures from 2012 to 2022. Factors including procedure type, admission urgency, and LOS were extracted from a prospectively maintained database. Six subspecialties were analyzed: Spine, Neuro-oncology, Skull base (SB), Functional, Cerebrospinal fluid (CSF), and Peripheral nerve (PN). Mann-Kendall temporal trend test and exploratory data analysis were performed. 19,237 elective and day case operations were analyzed. Of the 6 sub-specialties, spine, neuro-oncology, SB, and CSF procedures all showed a significant trend toward decreasing frequency. A shift toward day case over elective procedures was evident, especially in spine (P < 0.001), SB (tau = 0.733, P = 0.0042), functional (tau = 0.156, P = 0.0016), and PN surgeries (P < 0.005). Over the last decade, decreasing LOS was observed for neuro-oncology (tau = -0.648, P = 0.0077), SB (tau = -0.382, P = 0.012), and functional operations, a trend which remained consistent during the COVID-19 pandemic (P = 0.01). Spine remained constant across the decade while PN demonstrated a trend toward increasing LOS. Most subspecialties demonstrate a decreasing LOS coupled with a shift toward day case procedures, potentially attributable to improvements in surgical techniques, less invasive approaches, and increased pressure on beds. Setting up extra dedicated day case theaters could help deal with the backlog of procedures, particularly with regard to the impact of COVID-19.

P07.14.A OBSERVATIONS FROM THE FIRST 100 CASES OF INTRAOPERATIVE MRI - EXPERIENCES, TRENDS AND SHORT-TERM OUTCOMES IN PEDIATRIC VERSUS ADULT NEUROSURGICAL POPULATION

Abstract BACKGROUND The intraoperative MRI (iMRI) at Sahlgrenska University Hospital installed in 2017 was the first introduced in Sweden. Herein, we present a single center study with our observations from the first 100 patients undergoing neurosurgery in the dedicated iMRI surgical theater. METHODS Patients undergoing surgery in the 3T iMRI hybrid surgical theatre at our neurosurgical department between December 2017 to May 2021 were included after informed consent. Demographic, clinical, surgical, histological, radiological and outcome parameters, as well as variables related to iMRI, were retrospectively collected and analyzed. Patients were subdivided into adult and pediatric cohorts. RESULTS A variety of neurosurgical procedures were performed; resection of tumors and epileptic foci, endoscopic skull base procedures including pituitary lesions, deep brain stimulation (DBS), laser interstitial thermal therapy (LITT) and biopsies. Mean age was 32 years (range 0-81 years), 41 patients were pediatric and 42% were female. An iMRI scan was carried out in 96% of cases and led to continuation of surgery in 50 percent of cases, mainly due to visualized remaining pathological tissue. Median time to iMRI from intubation was 280 minutes and median total duration of surgery was 445 minutes. The majority of patients experienced no postoperative complications (70%), 13 patients suffered permanent postoperative deficits, predominantly visual. CONCLUSION We demonstrate demographics, clinical, surgical and radiological variables from the first 100 patients planned for surgery in the iMRI surgical theatre after INTRODUCTION in 2017. We found that iMRI was performed in almost all cases. In the pediatric cohort, tumors and epileptic focus were main indications for surgery. In adults, indications were intrinsic brain tumors, transsphenoidal pituitary tumor and DBS. Utilization from a resource and patients perspective appears to be most beneficial in tumor surgeries (specially pediatric), epileptic surgery and DBS.

410 Is a Single Dose, Single Agent Peri-Operative Antibiotic Protocol Adequate for Endoscopic Endonasal Skull Base Surgery? A 14-Year Review of 574 Cases

Abstract Post-operative meningitis is a rare but potentially fatal complication of endoscopic endonasal skull base surgery. As endonasal approaches to the skull base are clean-contaminated procedures, peri-operative antibiotics are routinely used. We sought to analyse the safety and efficacy of a single agent, single dose protocol in cases of endonasal anterior skull base surgery. Database of all endonasal anterior skull-base procedures performed in ENT Department at Leeds General Infirmary between 2008 and February 2022 was prospectively recorded. The primary outcome measure was development of meningitis within 30-days of surgery. Our protocol uses single dose of IV co-amoxiclav 1.2g (or teicoplanin if allergy precludes co-amoxiclav). The data was further divided according to primary or revision surgery, the presence or absence of intra-operative CSF leak, and the development or not of a post-operative CSF leak. Over the 14-year period, 574 endoscopic endonasal operations that fulfilled inclusion criteria were performed. The overall rate of post-operative meningitis across the entire cohort was 2.6%(n = 15). Among the 15 cases:80% (12/15) had intra-operative CSF leak47% (7/15) were revision cases73% (11/15) had extended endoscopic approach as pathology that required an intentional opening of the arachnoid80% (12/15) had post-operative CSF LeakThere were no cases of meningitis following repair of long-standing CSF fistula or encephalocele and surgery for sinonasal tumours with skull-base involvement. In conclusion, a single dose of 1.2g intravenous co-amoxiclav (or teicoplanin) is safe in the context of sellar-centred pathologies, repair of pre-existing spontaneous CSF leaks, and surgery on sinonasal tumours with skull base involvement.

A Novel Direct Pathway of Dural Venous Outflow from the Basilar Venous Plexus via the Diploic Space of the Clivus

The internal jugular vein (IJV) is the pre-eminent outflow of the dural venous sinuses (DVS) in the supine position, while the vertebral venous plexus (VVP) dominates venous outflow in the upright position. Emissary veins can also be an accessory pathway for this venous egress. To our knowledge, alternative dural venous sinus directly drainage via the diploic space has not been previously reported in the literature. Ten fresh frozen adult cadavers underwent exposure of the basilar venous plexus. The entire plexus, still adhered to the underlying clivus, was removed with its underlying bone and submitted for histological examination following decalcification (Masson Trichrome, 5μm slices). All specimens were found to have direct communication between the basilar venous plexus and underlying diploic space of the clivus i.e., no intermediate clival emissary vein. These were concentrated near the midline and were more numerous over the clivus near the junction of the occipital and sphenoid bones. The endothelium of the venous sinus was continuous at the opening into the diploic space and these openings ranged in size from 500 to 750μm (mean 650μm). An improved understanding of the cerebral venous drainage can assist clinicians and surgeons in recognizing normal, pathologic, and variant anatomy in this region. Based on our study, direct venous sinus (DVS) to diploic space drainage offers an additional pathway for venous egress from the intracranium. Therefore, removal of the dura over the clivus during various skull base procedures might be associated with increased venous bleeding from the basilar venous plexus on its deep surface where it interfaces with the clivus.

Ultrasound-guided endoscopic endonasal resection of sellar and suprasellar craniopharyngiomas.

Optimal planning and minimally invasive surgical approach are essential to complete craniopharyngiomas (CP) resection with limited postoperative morbidity. Given the nature of craniopharyngioma recurrence, complete resection of the neoplasm is crucial. Since CP arise from the pituitary stalk and may grow anteriorly or laterally, some cases require an extended endonasal craniotomy. The extension of the craniotomy is crucial to expose the whole tumor and to make its dissection from the surrounding structures feasible. In order to guide the extension of the approach, the intraoperative use of ultrasound is helpful for the surgeons. The objective of this paper is to describe and to demonstrate the applicability of the utilization of intraoperative ultrasound (US) guidance for planning and confirmation of craniopharyngioma resection in EES. The authors selected one operative video of a sellar-suprassellar craniopharyngioma gross-totally resected by EES. The authors demonstrate the extended sellar craniotomy, the anatomic landmarks that guide bone drilling and dural opening, the aspect of the intraoperative real time US, tumor resection and dissection from the surrounding structures. The solid component of the tumor was mostly isoechogenic in texture compared to the anterior pituitary gland, with several wide spread hyperechogenic images corresponding to calcifications and hypoechogenic vesicles corresponding to cysts inside the CF ("salt-and-pepper" pattern). The intraoperative endonasal US is a new surgical tool that allows for real-time active imaging for skull base procedures, such as sellar region tumors. Besides tumor evaluation, the intraoperative US helps the neurosurgeon to determine the size of craniotomy, to anticipate the relation between the tumor and vascular structures and to guide the best strategy for gross-total resection of the tumor. The EES allows a straight access to the craniopharyngiomas located in the sellar region or that grow anteriorly or superiorly. This approach allows the surgeon to dissect the tumor with minimal manipulation of the surrounding structures, when compared to craniotomy approaches. In order to accomplish that, the use of intraoperative endonasal ultrasound helps the neurosurgeon to perform the most suitable strategy, optimizing the rate of success.

Innovative growth and development of a neurological surgery residency cadaveric skull base simulation training program: A single institution experience

ObjectiveNeurosurgical cadaveric and simulation training is a valuable opportunity for residents and fellows to develop as neurosurgeons, further neuroanatomy knowledge, and develop decision-making and technical expertise. The authors describe the growth and development of Oregon Health & Science University (OHSU) Department of Neurological Surgery (NSG) resident hands-on simulation skull base course and provide details of course layout and setup. MethodsA three-part surgical simulation series was created to provide training in cadaveric skull base procedures. Course objectives were outlined for participants. Residents participated in NSG hands-on simulation courses (years 2015–2020) and completed annual course curriculum and anonymous course evaluations, which included free text reviews. Courses were evaluated by Likert scale analysis within Python, and free text was quantified using Valence Aware Dictionary for sEntiment Reasoning (VADER). Descriptive statistics were calculated and plotted using Python’s Seaborn and Matplotlib library modules. ResultsAnalysis included 162 skull base (anterior fossa, middle fossa and lateral, and endoscopic endonasal-based) simulation course evaluations. Resident responses were overwhelmingly positive. Likert responses demonstrated high average responses for each question (4.62 ± 0.56 and above). A positive attitude about simulation courses is supported by an average compound sentiment value of 0.558 ± 0.285. ConclusionThis is the first time Likert responses and sentiment analysis have been used to demonstrate how neurosurgical residents view a comprehensive, multi-year hands-on simulation training program. We hope the information presented serves as a guide for other institutions to develop their own residency educational curriculum in cadaveric skull base procedures.

Surgical Strategy in Modification of the Transpetrosal Approach to Avoid Postoperative Venous Complications: A Report of 74 Consecutive Cases.

The transpetrosal approach is a complex skull base procedure with a high risk of complications, particularly caused by injury of the venous system. It is in part related to variability of blood outflow pathways and their distinctive patterns in each individual patient. To evaluate outcomes and complications after skull base surgery with use of the petrosal approach modifications, which selection was based on the detailed preoperative assessment of venous drainage patterns. Overall, 74 patients, who underwent surgery via the transpetrosal approach at our institution between 2000 and 2017, were included in this study. In all cases, the venous drainage pattern was assessed preoperatively and categorized according to the predominant blood outflow pathway into four types as previously suggested by Hacker: (1) sphenoparietal sinus (SpPrt), (2) sphenobasal vein (SpB), (3) sphenopetrosal sinus (SpPS), and (4) cortical. The blood outflow through the bridging petrosal vein and the vein of Labbé was also taken into consideration. In patients with SpPrt- and a cortical-type venous drainage, the transpetrosal approach was used in a standard way. In patients with SpB-type venous drainage, limited extradural anterior petrosectomy was combined with intradural anterior petrosectomy after dural opening, superior petrosal sinus transection, tentorial cutting, Meckel's cave opening, and trigeminal nerve mobilization. In patients with SpPS-type venous drainage, after standard petrosectomy, dural opening, and tentorial cutting, SpPS ligation was done followed by 2-week interval before staged definitive tumor resection. Gross total, near-total, and subtotal resection of the lesion (meningioma, 48 cases; retrochiasmatic craniopharyngioma, 11 cases; brain stem cavernoma, 7 cases; other tumors, 8 cases) was achieved in 30 (40.5%), 24 (32.4%), and 20 (27.0%) patients, respectively. Postoperative complications that were possibly related to venous compromise were noted in 18 patients (24.3%), but neither one was major. Of these 18 patients, 9 were symptomatic, but all symptoms-aphasia (4 cases), seizures (2 cases), and confusion (3 cases)-fully resolved after conservative treatment. Overall, 13 patients, including 4 symptomatic, had signal changes on T2-weighted brain MRI, which were permanent only in 3 cases (all asymptomatic). Our suggested surgical strategy can be applied to any type of the venous drainage pattern. Preoperative evaluation and intraoperative preservation of the blood outflow pathways are crucial means for safe and effective application of the transpetrosal approach.

A first exploration of the economic consequences of an autonomous surgical robot for lateral skull base surgery: an early health technology assessment.

Lateral skull base procedures, such as translabyrinthine approach (TLA), are challenging. An autonomous surgical robot might be a solution to these challenges. Our aim is to explore in an early phase the economic consequences of an autonomous surgical robot compared with conventional TLA. An early decision analytic model was constructed in order to perform a step-wise threshold analyses and a sensitivity analysis to analyze the impact of the several factors on the incremental costs. Using surgical robot results in incremental costs - EUR 5,562 per procedure - compared to conventional TLA. These costs are most reduced by higher number of procedures, followed by lower price of the robot, saved operation time, and reduced risk of complication, respectively. The incremental costs of using an autonomous surgical robot can be decreased by choosing applications with a high turnover rate, a long operation time, and a high complication rate.

Does High-Definition 3-Dimensional Imaging Improve Orientation During Endoscopic Transsphenoidal Surgery? A Prospective Trial.

Endoscopy has evolved as the standard visualization tool for endonasal transsphenoidal resection of sellar lesions. The most widely used 2-dimensional (2D) endoscopes harbor the problem of limited depth perception. Therefore, 3-dimensional (3D) endoscopes have been developed to enable depth perception through a stereoscopic view. To evaluate the impact of high-definition (HD) 2D vs 3D HD endoscopes on spatial orientation within the sphenoid sinus. In this prospective single-center study, 21 patients have been investigated (2021-2022). Eleven standardized anatomic landmarks, which were preoperatively defined on neuronavigation imaging, were intraoperatively targeted with a navigation probe using either 2D HD or 3D HD endoscopes for visualization. Overall, 3D HD endoscopes provided a statistically significant higher accuracy of identification of sphenoid sinus landmarks (median deviation: 5.2 mm vs 4.2 mm, P < .001). In detail: tuberculum sellae (3.0 mm vs 4.3 mm, P = .047), most anterior point of sella (3.3 mm vs 4.8 mm, P = .049), and clivus indentation (3.8 mm vs 5.3 mm, P = .035). Anatomic variations such as a complex sphenoid sinus configuration had no influence on identifying sphenoid sinus landmarks. According to our data, stereoscopic 3D HD endoscopy enhances intraoperative orientation by improved depth perception within the sphenoid sinus. This may add to the safety of endoscopic skull base procedures, especially in extended approaches and cases with distorted anatomy.

Surgical Closure of the Eustachian Tube Through Middle Fossa and Transmastoid Approaches: A Pilot Cadaveric Anatomy Study.

Cerebrospinal fluid rhinorrhea after temporal bone surgery involves drainage from the Eustachian tube (ET) into the nasopharynx, causing significant patient morbidity. Variable anatomy of the ET accounts for failures of currently used ET obliteration techniques. To describe the surgical anatomy of the ET and examine possible techniques for ET closure through middle fossa (MF) and transmastoid approaches. We described the surgical anatomy of the ET from the MF and transmastoid approaches in 5 adult cadaveric heads, measuring morphometric and surgical anatomy parameters and establishing targets for definite ET obliteration. The osseous ET measured an average of 19.53 mm (±1.56 mm), with a mean diameter of 2.24 mm (±0.29 mm). The shortest distance between the greater superficial petrosal nerve and the ET junction was 6.61 mm (±0.61 mm). Shortest distances between the ET junction and the foramen spinosum and posterior border of the foramen ovale were 1.09 mm (±0.24 mm) and 2.03 mm (±0.30 mm), respectively. Closure of the cartilaginous ET may be performed by folding it in on itself, securing it by packing, suturing, or surgical clip ligation. Definite obliteration of the cartilaginous ET appears feasible and the most definite approach to eliminate egress of cerebrospinal fluid to the nasopharynx using the MF approach. This technique may be used as an adjunct to skull base procedures where ET closure is planned.

Systematic Review of Otologic and Neurotologic Surgery Using the 3-dimensional Exoscope.

The 3D exoscope is an emerging technology that has been met with success in neurosurgery and is now increasingly used in otologic and neurotologic surgery. There is currently no consensus on its safety, efficiency, and utility, compared to the traditional microscope for these procedures. This systematic review aims to evaluate the use of the 3-dimensional (3D) exoscope for otologic and neurotologic surgery. MEDLINE/PubMed, Web of Science, Scopus, and EMBASE. A systematic search of the databases was conducted for otologic and neurotologic surgery using the 3D exoscope. English language papers with no limit on the date of publication were considered. Inclusion criteria: full articles studying otologic or neurotologic/skull base surgery using exoscopes. Exclusion criteria: non-otologic surgery and non-neurotologic/skull base surgery, exclusive use of the traditional microscope, editorials, video reports, and letters. Two authors independently reviewed papers for inclusion; discrepancies were settled by consensus. Extracted variables included: number of patients, types of surgical procedures, operative and postoperative complications, setup and operative time, and visualization and ergonomic rating. Six articles containing 128 surgical cases (103 exoscopic and 25 microscopic) were analyzed. Of the exoscopic cases, 21% were surgeries for chronic ear disease, 5% were cochlear implants, and 74% were lateral skull base procedures encompassing a wide variety of approaches. Based on preliminary studies, the exoscope appears to be comparable in safety, visualization, and efficiency compared to the operating microscope, with the potential for increased comfort and ease of use.