The Role of Endonasal Endoscopic Skull Base Repair in Posttraumatic Tension Pneumocephalus.

OBJECTIVES: Information about the endonasal endoscopic approach (EEA) for the management of posttraumatic tension pneumocephalus (PTTP) remains scarce. Concomitant rhinoliquorrhea and posttraumatic hydrocephalus (PTH) can complicate the clinical course. METHODS: The authors systematically reviewed pertinent articles published between 1961 and December 2020 and identified 6 patients with PTTP treated by EEA in 5 reports. Additionally, the authors share their institutional experience including a seventh patient, where an EEA resolved a recurrent PTTP without rhinoliquorrhea. RESULTS: Seven PTTP cases in which EEA was used as part of the treatment regime were included in this review. All cases presented with a defect in the anterior skull base, and 3 of them had concomitant rhinoliquorrhea. A transcranial approach was performed in 6/7 cases before EEA was considered to treat PTTP. In 4/7 cases, the PTTP resolved after the first intent; in 2/ 7 cases a second repair was necessary because of recurrent PTTP, 1 with and 1 without rhinoliquorrhea, and 1/7 case because of recurrent rhinoliquorrhea only. Overall, PTTP treated by EEA resolved with a mean radiological resolution time of 69 days (range 23-150 days), with no late recurrences. Only 1 patient developed a cerebrospinal fluid diversion infection probably related to a first incomplete EEA skull base defects repair. A permanent cerebrospinal fluid diversion was necessary in 3/7 cases. CONCLUSIONS: Endonasal endoscopic approach repair of air conduits is a safe and efficacious second-line approach after failed transcranial approaches for symptomatic PTTP. However, the strength of recommendation for EEA remains low until further evidence is presented.

The utilisation of 3D printing in paediatric neurosurgery.

3D printing technology has evolved over the years and there is a growing interest in its application in paediatric neurosurgery. Modern 3D printers have enabled the development of patient-specific 3D models that provide a realistic representation of complex anatomies and will aid in planning complex procedures. Paediatric neurosurgical operations are challenging and hands-on training is restricted. Surgical simulation training with biomodel has provided a new paradigm for trainees to master their surgical skills before encountering similar scenarios in real-life environment. This paper reviews the aspects of 3D printing for preoperative planning and simulation-based surgical training in paediatric neurosurgery.

Employment status after traumatic brain injury and the effect of concomitant injuries on return to work.

PURPOSE: This study aims to describe the employment status and pattern among survivors of traumatic brain injury after motor vehicle accidents, and to explore the effects of demographic, injury variables and concomitant injuries on the employment status . METHOD: A retrospective analyses of 370 medical reports written for patients who sustained traumatic brain injury from motor vehicle accidents was conducted. To establish the employment pattern, the pre-injury employment history was compared to the latest employment status documented. Types and severity of concomitant injuries were rated according to Abbreviated Injury Scale criteria. All significant variables were further analyzed using logistic regression to explore predictors of employment. RESULTS: Up to 87% of the patients sustained concomitant injuries, with more than two-thirds (72%) scoring ≤ 2 on the Abbreviated Injury Scale. One hundred and eighty-two patients (49.2%) successfully returned to work. Among those who returned to work, 34% returned to former employment with pre-injury job description. Severity of traumatic brain injury, length of acute hospital stay, ambulation status and cognitive status were found to be significant predictive factors for employment status post traumatic brain injury. Presence of concomitant extremity injuries was found to influence the employment pattern among traumatic brain injury survivors. CONCLUSION: The return to work rate was somewhat low and was not influenced by presence of concomitant injuries. .

Consensus statement from the International Consensus Meeting on the Role of Decompressive Craniectomy in the Management of Traumatic Brain Injury : Consensus statement.

BACKGROUND: Two randomised trials assessing the effectiveness of decompressive craniectomy (DC) following traumatic brain injury (TBI) were published in recent years: DECRA in 2011 and RESCUEicp in 2016. As the results have generated debate amongst clinicians and researchers working in the field of TBI worldwide, it was felt necessary to provide general guidance on the use of DC following TBI and identify areas of ongoing uncertainty via a consensus-based approach. METHODS: The International Consensus Meeting on the Role of Decompressive Craniectomy in the Management of Traumatic Brain Injury took place in Cambridge, UK, on the 28th and 29th September 2017. The meeting was jointly organised by the World Federation of Neurosurgical Societies (WFNS), AO/Global Neuro and the NIHR Global Health Research Group on Neurotrauma. Discussions and voting were organised around six pre-specified themes: (1) primary DC for mass lesions, (2) secondary DC for intracranial hypertension, (3) peri-operative care, (4) surgical technique, (5) cranial reconstruction and (6) DC in low- and middle-income countries. RESULTS: The invited participants discussed existing published evidence and proposed consensus statements. Statements required an agreement threshold of more than 70% by blinded voting for approval. CONCLUSIONS: In this manuscript, we present the final consensus-based recommendations. We have also identified areas of uncertainty, where further research is required, including the role of primary DC, the role of hinge craniotomy and the optimal timing and material for skull reconstruction.

Combined transnasal and transoral endoscopic approach to a transsphenoidal encephalocele in an infant.

PURPOSE: This paper reports an unusual case of a transsphenoidal encephalocele and discusses our experience with a minimally invasive management. To the best of our knowledge, we present the first case of a combined endoscopic transnasal and transoral approach to a transsphenoidal encephalocele in an infant. METHODS: A 17-day-old boy, who was referred for further assessment of upper airway obstruction, presented with respiratory distress and feeding difficulties. Bronchoscopy and imaging revealed a transsphenoidal encephalocele. At the age of 48 days, he underwent a combined endoscopic transnasal and transoral excision of the nasal component of the encephalocele. This approach, with the aid of neuronavigation, allows good demarcation of the extra-cranial neck of the transsphenoidal encephalocele. We were able to cauterize and carefully dissect the sac prior to excision. The defect of the neck was clearly visualized, and Valsalva manoeuvre was performed to exclude any CSF leak. As the defect was small, it was allowed to heal by secondary intention. RESULTS: The patient's recovery was uneventful, and he tolerated full feeds orally on day 2. Postoperative imaging demonstrated no evidence of recurrence of the nasal encephalocele. Endoscopic follow-up showed good healing of the mucosa and no cerebrospinal fluid leak. CONCLUSIONS: The surgical management of transsphenoidal encephalocele in neonates and infants is challenging. We describe a safe technique with low morbidity in managing such a condition. The combined endoscopic transnasal and transoral approach with neuronavigation is a minimally invasive, safe and feasible alternative, even for children below 1 year of age.

Combined endoscopic transnasal and transoral approach for extensive upper cervical osteoradionecrosis.

PURPOSE: Osteoradionecrosis (ORN) is a rare yet well-recognized complication following radiotherapy to the head and neck. We illustrate the only case of a spontaneous extrusion of the sequestered C1 arch through the oral cavity and discuss our experience with a combined endoscopic transnasal and transoral approach for cervical ORN. METHODS: A 56-year-old female presented with a 3-month history of blood-stained nasal discharge. She had been treated with radiotherapy for nasopharyngeal carcinoma 25 years earlier. Flexible nasal endoscopy demonstrated an exposed bone with an edematous posterior nasopharyngeal mass. Computed tomography showed a pre-vertebral mass with destruction of C1 and C2. She underwent occipito-cervical fusion followed by a combined transnasal and transoral endoscopic debridement of non-viable bone in the same perioperative setting. Healing of the raw mucosa was by secondary intention and reconstruction was not performed. RESULTS: Histopathological examination reported ulcerated inflamed granulation tissue with no evidence of malignancy. During follow-up, she remained neurologically intact with no recurrence. CONCLUSION: Using both nasal and oral spaces allows placement of the endoscope in the nasal cavity and surgical instruments in the oral cavity without splitting the palate. Hence, the endoscopic transnasal and transoral approach has vast potential to be effective in carefully selected cases of cervical ORN.

Endoscopic skull base training using 3D printed models with pre-existing pathology.

Endoscopic base of skull surgery has been growing in acceptance in the recent past due to improvements in visualisation and micro instrumentation as well as the surgical maturing of early endoscopic skull base practitioners. Unfortunately, these demanding procedures have a steep learning curve. A physical simulation that is able to reproduce the complex anatomy of the anterior skull base provides very useful means of learning the necessary skills in a safe and effective environment. This paper aims to assess the ease of learning endoscopic skull base exposure and drilling techniques using an anatomically accurate physical model with a pre-existing pathology (i.e., basilar invagination) created from actual patient data. Five models of a patient with platy-basia and basilar invagination were created from the original MRI and CT imaging data of a patient. The models were used as part of a training workshop for ENT surgeons with varying degrees of experience in endoscopic base of skull surgery, from trainees to experienced consultants. The surgeons were given a list of key steps to achieve in exposing and drilling the skull base using the simulation model. They were then asked to list the level of difficulty of learning these steps using the model. The participants found the models suitable for learning registration, navigation and skull base drilling techniques. All participants also found the deep structures to be accurately represented spatially as confirmed by the navigation system. These models allow structured simulation to be conducted in a workshop environment where surgeons and trainees can practice to perform complex procedures in a controlled fashion under the supervision of experts.

Endoscopic transnasal approach to anterior and middle cranial base lesions.

We present our experience in managing pathologies involving the anterior and middle cranial base using an endoscopic transnasal approach, highlighting the surgical technique, indications, and complications. The different types of endoscopic approaches used include the transtuberculum/transplanum, transcribiform, transsellar, and cavernous sinus approaches. The common indications include repair of cerebrospinal fluid leaks (both spontaneous and post traumatic) and excision of pituitary adenomas, meningiomas, craniopharyngiomas, esthesioneuroblastomas, and other malignancies of the anterior cranial base. Careful reconstruction is performed with the multilayer technique utilizing fat, fascia lata, and fibrin sealant. The endoscopic transnasal approach, coupled with the present-day sophisticated neuronavigation systems, allows access to lesions in the midline extending from the cribriform plate to the craniovertebral junction. However, preoperative planning and careful selection of cases with evaluation of each case on an individual basis with regard to the lateral extension of the lesion are imperative.

Intrasellar pituitary mucocele: diagnostic dilemma.

Isolated intrasellar pituitary mucocele following transsphenoidal sinus surgery is extremely rare. The clinical features resemble a pituitary tumor, therefore careful radiological interpretation is crucial to reach the correct diagnosis. We report a case of intrasellar mucocele who had transsphenoidal sinus surgery performed 15 years prior.

Consensus-Based Development of a Global Registry for Traumatic Brain Injury: Establishment, Protocol, and Implementation.

BACKGROUND AND OBJECTIVES: Global disparity exists in the demographics, pathology, management, and outcomes of surgically treated traumatic brain injury (TBI). However, the factors underlying these differences, including intervention effectiveness, remain unclear. Establishing a more accurate global picture of the burden of TBI represents a challenging task requiring systematic and ongoing data collection of patients with TBI across all management modalities. The objective of this study was to establish a global registry that would enable local service benchmarking against a global standard, identification of unmet need in TBI management, and its evidence-based prioritization in policymaking. METHODS: The registry was developed in an iterative consensus-based manner by a panel of neurotrauma professionals. Proposed registry objectives, structure, and data points were established in 2 international multidisciplinary neurotrauma meetings, after which a survey consisting of the same data points was circulated within the global neurotrauma community. The survey results were disseminated in a final meeting to reach a consensus on the most pertinent registry variables. RESULTS: A total of 156 professionals from 53 countries, including both high-income countries and low- and middle-income countries, responded to the survey. The final consensus-based registry includes patients with TBI who required neurosurgical admission, a neurosurgical procedure, or a critical care admission. The data set comprised clinically pertinent information on demographics, injury characteristics, imaging, treatments, and short-term outcomes. Based on the consensus, the Global Epidemiology and Outcomes following Traumatic Brain Injury (GEO-TBI) registry was established. CONCLUSION: The GEO-TBI registry will enable high-quality data collection, clinical auditing, and research activity, and it is supported by the World Federation of Neurosurgical Societies and the National Institute of Health Research Global Health Program. The GEO-TBI registry ( https://geotbi.org ) is now open for participant site recruitment. Any center involved in TBI management is welcome to join the collaboration to access the registry.

A new modified speculum guided single nostril technique for endoscopic transnasal transsphenoidal surgery: an analysis of nasal complications.

Abstract The endoscopic transnasal, transsphenoidal surgical technique for pituitary tumour excision has generally been regarded as a less invasive technique, ranging from single nostril to dual nostril techniques. We propose a single nostril technique using a modified nasal speculum as a preferred technique. We initially reviewed 25 patients who underwent pituitary tumour excision, via endoscopic transnasal transsphenoidal surgery, using this new modified speculum-guided single nostril technique. The results show shorter operation time with reduced intra- and post-operative nasal soft tissue injuries and complications.

Outcome of 1939 traumatic brain injury patients from road traffic accidents: Findings from specialist medical reports in a low to middle income country (LMIC).

OBJECTIVE: Road traffic accident (RTA) is the major cause of traumatic brain injury (TBI) in developing countries and affects mostly young adult population. This research aimed to describe the factors predicting functional outcome after TBI caused by RTA in a Malaysian setting. METHODS: This was a retrospective cross-sectional study conducted on specialist medical reports written from 2009 to 2019, involving patients who survived after TBI from RTA. The functional outcome was assessed using the Glasgow Outcome Scale-Extended (GOSE). Factors associated with good outcome were analysed via logistic regression analysis. Multivariate logistic regression analysis was used to derive the best fitting Prediction Model and split-sample cross-validation was performed to develop a prediction model. RESULTS: A total of 1939 reports were evaluated. The mean age of the study participants was 32.4 ± 13.7 years. Most patients were male, less than 40, and with average post RTA of two years. Good outcome (GOSE score 7 & 8) was reported in 30.3% of the patients. Factors significantly affecting functional outcome include age, gender, ethnicity, marital status, education level, severity of brain injury, neurosurgical intervention, ICU admission, presence of inpatient complications, cognitive impairment, post-traumatic headache, post traumatic seizures, presence of significant behavioural issue; and residence post discharge (p<0.05). After adjusting for confounding factors, prediction model identified age less than 40, mild TBI, absence of post traumatic seizure, absence of behaviour issue, absence of cognitive impairment and independent living post TBI as significant predictors of good functional outcome post trauma. Discrimination of the model was acceptable (C-statistic, 0.67; p<0.001, 95% CI: 0.62-0.73). CONCLUSION: Good functional outcome following TBI due to RTA in this study population is comparable to other low to middle income countries but lower than high income countries. Factors influencing outcome such as seizure, cognitive and behavioural issues, and independent living post injury should be addressed early to achieve favourable long-term outcomes.

Supratentorial cerebrospinal fluid diversion using image-guided trigonal ventriculostomy during retrosigmoid craniotomy for cerebellopontine angle tumors.

Background: Cerebellar contusion, swelling and herniation is frequently encoutered upon durotomy in patients undergoing retrosigmoid craniotomy for cerebellopontine angle (CPA) tumors, despite using standard methods to obtain adequate cerebellar relaxation. Objective: The aim of this study is to report an alternative cerebrospinal fluid (CSF)-diversion method using image-guided ipsilateral trigonal ventriculostomy. Methods: Single-center retro- and prospective cohort study of n = 62 patients undergoing above-mentioned technique. Prior durotomy, CSF-diversion was performed to the point where the posterior fossa dura was visibly pulsatile. Outcome assessment consisted of the surgeon's intra- and postoperative clinical observations, and postoperative radiological imaging. Results: Fifty-two out of n = 62 (84%) cases were eligible for analysis. The surgeons consistently reported successful ventricular puncture and a pulsatile dura prior durotomy without cerebellar contusion, swelling or herniation through the dural incision in n = 51/52 (98%) cases. Forty-nine out of n = 52 (94%) catheters were placed correctly within the first attempt, with the majority of catheter tips (n = 50, 96%) located intraventricularly (grade 1 or 2). In n = 4/52 (8%) patients, postoperative imaging revealed evidence of a ventriculostomy-related hemorrhage (VRH) associated with an intracerebral hemorrhage [n = 2/52 (4%)] or an isolated intraventricular hemorrhage [n = 2/52 (4%)]. However, these hemorrhagic complications were not associated with neurological symptoms, surgical interventions or postoperative hydrocephalus. None of the evaluated patients demonstrated radiological signs of upward transtentorial herniation. Conclusion: The method described above efficiently allows CSF-diversion prior durotomy to reduce cerebellar pressure during retrosigmoid approach for CPA tumors. However, there is an inherent risk of subclinical supratentorial hemorrhagic complications.

An international, prospective observational study on traumatic brain injury epidemiology study protocol: GEO-TBI: Incidence.

Background: The epidemiology of traumatic brain injury (TBI) is unclear - it is estimated to affect 27-69 million individuals yearly with the bulk of the TBI burden in low-to-middle income countries (LMICs). Research has highlighted significant between-hospital variability in TBI outcomes following emergency surgery, but the overall incidence and epidemiology of TBI remains unclear. To address this need, we established the Global Epidemiology and Outcomes following Traumatic Brain Injury (GEO-TBI) registry, enabling recording of all TBI cases requiring admission irrespective of surgical treatment. Objective: The GEO-TBI: Incidence study aims to describe TBI epidemiology and outcomes according to development indices, and to highlight best practices to facilitate further comparative research. Design: Multi-centre, international, registry-based, prospective cohort study. Subjects: Any unit managing TBI and participating in the GEO-TBI registry will be eligible to join the study. Each unit will select a 90-day study period. All TBI patients meeting the registry inclusion criteria (neurosurgical/ICU admission or neurosurgical operation) during the selected study period will be included in the GEO-TBI: Incidence. Methods: All units will form a study team, that will gain local approval, identify eligible patients and input data. Data will be collected via the secure registry platform and validated after collection. Identifiers may be collected if required for local utility in accordance with the GEO-TBI protocol. Data: Data related to initial presentation, interventions and short-term outcomes will be collected in line with the GEO-TBI core dataset, developed following consensus from an iterative survey and feedback process. Patient demographics, injury details, timing and nature of interventions and post-injury care will be collected alongside associated complications. The primary outcome measures for the study will be the Glasgow Outcome at Discharge Scale (GODS) and 14-day mortality. Secondary outcome measures will be mortality and extended Glasgow Outcome Scale (GOSE) at the most recent follow-up timepoint.

Traumatic brain injury (TBI) is a significant global health problem, which affects 27­69 million people every year. After-effects of TBI commonly affect the injured individuals for years. Most patients who sustain a TBI are from developing countries. Research has shown that there are differences in patients' recovery after TBI between countries and hospitals. The causes of these differences are unclear and tackling them could improve TBI treatment worldwide. To address this need, we have recently established the Global Epidemiology and Outcomes Following Traumatic Brain Injury (GEO-TBI) registry. The international collaborative registry aims to collect data related to the causes, treatments and outcomes related to TBI patients. This data will hopefully enable future research to elucidate the causes of the recovery differences between hospitals, which could lead to improved patient outcomes. The GEO-TBI: Incidence study collects data from all TBI patients that are admitted to participating hospitals or undergo a neurosurgical operation due to TBI during a 90-day period. This study looks at the patient's recovery at discharge using the Glasgow Outcome at Discharge Scale (GODS), and at the 2-week mortality. In addition, the study also evaluates recovery at the most recent follow-up timepoint. We hope that this information will enhance our understanding on the causes, treatments, and commonness of TBI. The study results will also help local hospitals compare their treatment results to an international standard.

Video clip transfer of radiological images using a mobile telephone in emergency neurosurgical consultations (3G Multi-Media Messaging Service).

BACKGROUND: The purpose of this study was to validate and assess the accuracy and usefulness of sending short video clips in 3gp file format of an entire scan series of patients, using mobile telephones running on 3G-MMS technology, to enable consultation between junior doctors in a neurosurgical unit and the consultants on-call after office hours. METHOD: A total of 56 consecutive patients with acute neurosurgical problems requiring urgent after-hours consultation during a 6-month period, prospectively had their images recorded and transmitted using the above method. The response to the diagnosis and the management plan by two neurosurgeons (who were not on site) based on the images viewed on a mobile telephone were reviewed by an independent observer and scored. In addition to this, a radiologist reviewed the original images directly on the hospital's Patients Archiving and Communication System (PACS) and this was compared with the neurosurgeons' response. RESULTS: Both neurosurgeons involved in this study were in complete agreement with their diagnosis. The radiologist disagreed with the diagnosis in only one patient, giving a kappa coefficient of 0.88, indicating an almost perfect agreement. CONCLUSION: The use of mobile telephones to transmit MPEG video clips of radiological images is very advantageous for carrying out emergency consultations in neurosurgery. The images accurately reflect the pathology in question, thereby reducing the incidence of medical errors from incorrect diagnosis, which otherwise may just depend on a verbal description.

Equitable Access to State-of-the-Art Medical Technology-a Malaysian Mini-Public-Private Partnership Case Study.

BACKGROUND: The provision of equitable and affordable health care has become increasingly challenging as advanced technology is introduced, particularly in developing countries. We explored the hypothesis that focused, small-scale mini-public-private partnerships have a potential role in providing equitable and affordable access to advanced technology for the benefit of all patients in developing nations, particularly middle-income countries. METHODS: A clinician-led financial plan was developed at the University of Malaya to create the Centre for Image Guidance and Minimally Invasive Therapy (CIGMIT) to provide an integrated platform for high-end care for Malaysian patients of all ages, both public and private, requiring complex neurosurgical and spinal procedures and stereotactic and intensity-modulated radiotherapy. The challenges faced during development of the plan were documented together with an audit of patient throughput and analyses of financial risk and return. RESULTS: CIGMIT opened in 2015. Patient throughput, both public and private, progressively increased in all facilities. In 2015-2019, 37,724 patients used the Centre's facilities. CIGMIT has become progressively more profitable for the University of Malaya, the public and private hospitals, and the investor. CIGMIT has weathered the challenges posed by coronavirus disease 19. CONCLUSIONS: Focused, small-scale mini-public-private partnerships have a potential role in providing advanced technology for the benefit of patients in developing nations, particularly middle-income countries, subject to an approach that balances equity of access between public and private health care systems with fair reward.

Telemedicine via Smart Glasses in Critical Care of the Neurosurgical Patient-COVID-19 Pandemic Preparedness and Response in Neurosurgery.

OBJECTIVE: The coronavirus disease 2019 pandemic poses major risks to health care workers in neurocritical care. Recommendations are in place to limit medical personnel attending to the neurosurgical patient as a protective measure and to conserve personal protective equipment. However, the complexity of the neurosurgical patient proves to be a challenge and an opportunity for innovation. The goal of our study was to determine if telemedicine delivered through smart glasses was feasible and effective in an alternative method of conducting ward round on neurocritical care patients during the pandemic. METHODS: A random pair of neurosurgery resident and specialist conducted consecutive virtual and physical ward rounds on neurocritical patients. A virtual ward round was first conducted remotely by a specialist who received real-time audiovisual information from a resident wearing smart glasses integrated with telemedicine. Subsequently, a physical ward round was performed together by the resident and specialist on the same patient. The management plans of both ward rounds were compared, and the intrarater reliability was measured. On study completion a qualitative survey was performed. RESULTS: Ten paired ward rounds were performed on 103 neurocritical care patients with excellent overall intrarater reliability. Nine out of 10 showed good to excellent internal consistency, and 1 showed acceptable internal consistency. Qualitative analysis indicated wide user acceptance and high satisfaction rate with the alternative method. CONCLUSIONS: Virtual ward rounds using telemedicine via smart glasses on neurosurgical patients in critical care were feasible, effective, and widely accepted as an alternative to physical ward rounds during the coronavirus disease 2019 pandemic.

Clinical Studies and Pre-clinical Animal Models on Facial Nerve Preservation, Reconstruction, and Regeneration Following Cerebellopontine Angle Tumor Surgery-A Systematic Review and Future Perspectives.

Background and purpose: Tumorous lesions developing in the cerebellopontine angle (CPA) get into close contact with the 1st (cisternal) and 2nd (meatal) intra-arachnoidal portion of the facial nerve (FN). When surgical damage occurs, commonly known reconstruction strategies are often associated with poor functional recovery. This article aims to provide a systematic overview for translational research by establishing the current evidence on available clinical studies and experimental models reporting on intracranial FN injury. Methods: A systematic literature search of several databases (PubMed, EMBASE, Medline) was performed prior to July 2020. Suitable articles were selected based on predefined eligibility criteria following the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. Included clinical studies were reviewed and categorized according to the pathology and surgical resection strategy, and experimental studies according to the animal. For anatomical study purposes, perfusion-fixed adult New Zealand white rabbits were used for radiological high-resolution imaging and anatomical dissection of the CPA and periotic skull base. Results: One hundred forty four out of 166 included publications were clinical studies reporting on FN outcomes after CPA-tumor surgery in 19,136 patients. During CPA-tumor surgery, the specific vulnerability of the intracranial FN to stretching and compression more likely leads to neurapraxia or axonotmesis than neurotmesis. Severe FN palsy was reported in 7 to 15 % after vestibular schwannoma surgery, and 6% following the resection of CPA-meningioma. Twenty-two papers reported on experimental studies, out of which only 6 specifically used intracranial FN injury in a rodent (n = 4) or non-rodent model (n = 2). Rats and rabbits offer a feasible model for manipulation of the FN in the CPA, the latter was further confirmed in our study covering the radiological and anatomical analysis of perfusion fixed periotic bones. Conclusion: The particular anatomical and physiological features of the intracranial FN warrant a distinguishment of experimental models for intracranial FN injuries. New Zealand White rabbits might be a very cost-effective and valuable option to test new experimental approaches for intracranial FN regeneration. Flexible and bioactive biomaterials, commonly used in skull base surgery, endowed with trophic and topographical functions, should address the specific needs of intracranial FN injuries.

Identifying the Sources of Error When Using 3-Dimensional Printed Head Models with Surgical Navigation.

OBJECTIVES: The evaluation of sources of error when preparing, printing, and using 3-dimensional (3D) printed head models for training purposes. METHODS: Two 3D printed models were designed and fabricated using actual patient imaging data with reference marker points embedded artificially within these models that were then registered to a surgical navigation system using 3 different methods. The first method uses a conventional manual registration, using the actual patient's imaging data. The second method is done by directly scanning the created model using intraoperative computed tomography followed by registering the model to a new imaging dataset manually. The third is similar to the second method of scanning the model but eventually uses an automatic registration technique. The errors for each experiment were then calculated based on the distance of the surgical navigation probe from the respective positions of the embedded marker points. RESULTS: Errors were found in the preparation and printing techniques, largely depending on the orientation of the printed segment and postprocessing, but these were relatively small. Larger errors were noted based on a couple of variables: if the models were registered using the original patient imaging data as opposed to using the imaging data from directly scanning the model (1.28 mm vs. 1.082 mm), and the accuracy was best using the automated registration techniques (0.74 mm). CONCLUSION: Spatial accuracy errors occur consistently in every 3D fabricated model. These errors are derived from the fabrication process, the image registration process, and the surgical process of registration.

Evolving Strategies for Resection of Sellar/Parasellar Synchronous Tumors via Endoscopic Endonasal Approach: A Technical Case Report and Systematic Review of the Literature.

BACKGROUND: Data on the endonasal endoscopic approach (EEA) to treat sellar/parasellar synchronous tumors remain sparse. This work aims to describe a minimally invasive approach with intraoperative magnetic resonance imaging (MRI) to remove a large sellar/parasellar synchronous tumor, and presents a systematic literature review. METHODS: The preoperative MRI of a 54-year-old woman revealed a sellar lesion (28 × 19 × 16 mm), presumably a pituitary macroadenoma, and a second extra-axial lesion (22 × 36 × 20 mm) expanding from the tuberculum sellae to the planum sphenoidale with encasement of the anterior communicating complex, presumably a meningioma. We used intraoperative MRI to assess the extent of the resection before reconstructing the large skull base defect. Furthermore, we systematically reviewed pertinent articles retrieved by a PubMed/Embase database search between 1961 and December 2018. RESULTS: Out of 63 patients with synchronous tumors reported in 43 publications, we found 3 patients in which the tumor was removed by EEA. In these 3 patients and the presented case, the resection of both lesions was successful, without major approach-related morbidity or mortality. More extensive removal of endonasal structures to gain an adequate tumor exposure was not necessary. We did not find any previous reports describing the benefits of intraoperative MRI in the presented setting. CONCLUSIONS: In the rare case of a synchronous meningioma and pituitary adenoma of the sellar region, intraoperative MRI might be beneficial in confirming residual disease before skull base reconstruction, and therefore radiologic follow-up.