Frontal Skull Base Research Articles

Understanding the heterogenicity of unicoronal synostosis – A morphometric analysis of cases compared to controls

BackgroundPreoperative severity of unicoronal synostosis varies greatly and involves the frontal bone, skull base and orbits. Degree of deformity affects long-term morphological and functional outcome after surgery. The aim of this study was to describe the morphological heterogenicity and investigate its relation to patient-specific factors. Materials and methodsIn this retrospective cohort study, non-syndromic unicoronal synostosis patients treated between 2006-2022 at Necker Hospital, France, or Uppsala University Hospital, Sweden, were included and matched to controls. Severity of skull base, orbital and posterior skull asymmetry, degree of anterior plagiocephaly and Harlequin deformity, lateralization, head circumference, age, timing of metopic fusion and fusion of peri-pterionic sutures were investigated. ResultsNinety-five patients and ninety-three controls were included. Skull base asymmetry was linearly related to orbital asymmetry (p < 0.001), correlated with earlier CT scans (p = 0.004), anterior (p < 0.001) and posterior (p = 0.03) plagiocephaly. Posterior plagiocephaly was more common in patients (31%) compared with controls (5%) (p < 0.001). A patent metopic suture above nine months of age was associated with severe Harlequin deformity (p = 0.04) and lower head circumference when fused (p = 0.03). Fronto-sphenoidal suture fusion was associated with later CT scans (p < 0.001) and less skull base asymmetry (p = 0.002). Spheno-parietal fusion was correlated with decreased skull base asymmetry. Right lateralization was more common in females. ConclusionHeterogenicity of unicoronal synostosis seems to be predominantly explained by variability in skull base morphology. Peri-pterionic fusions might limit deformity.

Anterior interhemispheric vs. pterional approach in the microsurgical management of anterior communicating artery aneurysms: a comparative analysis employing a novel multidimensional matching-tool

The surgical management of anterior communicating artery aneurysms (AcomA) is challenging due to their deep midline position and proximity to complex skull base anatomy. This study compares the pterional craniotomy with the interhemispheric approach based on the specific aneurysm angulation. A total of 129 AcomA cases were analyzed, with 50 undergoing microsurgical clipping via either the pterional or interhemispheric approach. All selected cases had computed tomography-angiography with sagittal imaging slices and 2D-angiography. Using an interactive tool, 14 cases treated via the interhemispheric approach were matched with 14 cases approached pterionally based on clinical and morphological parameters, emphasizing intracranial aneurysm (IA) dome angulation relative to the frontal skull base. Outcomes included IA occlusion, temporary clipping incidence, intraoperative rupture, postoperative strokes, hemorrhages, hydrocephalus, vasospasm, and patient functionality. Matched cohorts had consistent demographics. Both approaches resulted in similar IA occlusion rates, but the interhemispheric approach led to improved clinical outcomes, measured by the modified Rankin Scale. It also had a lower incidence of hydrocephalus and reduced need for permanent ventriculoperitoneal shunt placement. Vasospasms and postoperative infarction rates were comparable between the groups. Our findings suggest potential advantages of the interhemispheric approach in managing AcomA, depending on aneurysm angulation. Despite a small sample size, the results highlight the importance of customized surgical decision-making based on the unique traits of each aneurysm and the surgeon's expertise.

Extended Unifrontal craniotomy for midline anterior cranial fossa meningiomas: A better shot at preservation of neurovascular structures

Numerous surgical approaches have been described for the resection of anterior cranial fossa meningioma. The common problems associated with these approaches are excessive brain retraction, injury to neurovascular structures, transection of superior sagittal sinus (SSS), and a higher risk of new-onset anosmia. The authors describe a unilateral extended frontal approach with the aim to minimize brain handling without the need for SSS transection and possibly better olfaction preservation. Methods: Thirteen patients with anterior cranial fossa meningioma were operated on using the novel technique of unilateral extended frontal skull base approach. The clinical presentation, radiological studies, intraoperative findings, and outcome at follow-up were recorded. Results: Gross total tumor resection could be achieved in 12 out of 13 patients. At least one of the olfactory tracts could be anatomically preserved in all patients, and superior sagittal sinus was preserved in all patients. Functional olfaction preservation was achieved in 8 patients. No patient developed new-onset anosmia. Conclusions: The extended unilateral frontal approach is a viable and reliable alternative for extended bifrontal technique for the resection of large midline anterior cranial fossa meningiomas with avoidance of SSS ligation, decreased brain handling with better olfaction preservation while achieving comparable tumor resection and acceptable cosmetic outcomes.

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.

Biphenotypic Sinonasal Sarcoma: A Genetically Confirmed Case Showing Bone Invasion Accompanying a Non-neoplastic Respiratory Epithelium.

Biphenotypic sinonasal sarcoma is a newly established tumor entity that is associated with distinct clinicopathological findings. Biphenotypic sinonasal sarcoma is a rare, low-grade spindle cell sarcoma that arises in middle-aged females, exclusively in the sinonasal tract. A fusion gene involving PAX3 is detected in most biphenotypic sinonasal sarcomas, which aids in its diagnosis. Here, we report a case of biphenotypic sinonasal sarcoma with its cytological findings. The patient was a 73-year-old woman who presented with purulent nasal discharge and dull pain in the left cheek area. Computed tomography showed a mass extending from the left nasal cavity to the left ethmoid sinus, the left frontal sinus, and the frontal skull base. She underwent a combined transcranial and endoscopic approach for en bloc resection with a safety margin. Histologically, spindle-shaped tumor cells have been thought to proliferate mainly in the subepithelial stroma. Here, nasal mucosal epithelial hyperplasia was noted, and the tumor had invaded the bone tissue accompanying the epithelial cells. Fluorescence in situ hybridization (FISH) analysis showed a PAX3 rearrangement, and next-generation sequencing identified a PAX3::MAML3 fusion. Based on FISH, split signals were observed not in respiratory cells but in stromal cells. This indicated that respiratory cells were non-neoplastic. In the diagnosis of biphenotypic sinonasal sarcoma, the inverted growth of the respiratory epithelium can be a diagnostic pitfall. FISH analysis using a PAX3 break-apart probe is helpful not only for an accurate diagnosis but also for detecting the true neoplastic cells.

Supraorbital eyebrow approach: A single-center experience.

Keyhole neurosurgery is the notion of safely removing brain and skull base lesions through smaller and more precise openings that lessen collateral damage to the surrounding scalp, brain, blood vessels, and nerves. The traditional frontal and pterional approaches require large craniotomies and this predisposes patients to significant and avoidable morbidity. With the growing expectation for minimally invasive surgery, we present our experience with the supraorbital keyhole craniotomy for surgical lesions in the anterior cranial fossa and parasellar regions. We retrospectively analyzed and evaluated all cases of neoplastic, vascular, trauma, and infective pathologies of the anterior fossa and parasellar regions treated using a keyhole approach, the supraorbital eyebrow (SOE) approach from January 2018 to June 2022. Treatment outcomes were evaluated based on pathology. A total of 50 patients underwent a SOE craniotomy during the study period (28 females and 22 males). Their average age ranged from 12 to 86 years, with a mean age of 47.4 years. All patients had anterior skull base and/or anterior frontal lobe pathologies: (23 tumors, 17 ruptured aneurysms, five traumatic frontal hematomas, three extradural empyema, one cerebral cavernous malformation, and one traumatic frontal skull base fracture with dural tear and CSF leak). Gross total tumor resection was achieved in 87% of cases (13 meningiomas of which six were giant, three gliomas, two craniopharyngiomas, and two cerebral metastases). Clip ligation occlusion rate for our aneurysm cases was 100% and intraoperative rerupture was observed in three cases. Mean ICU stay was 2.2 days for the entire series. The overall 30-day mortality rate for our series was 16% (eight deaths). This was highest in the ruptured aneurysm subgroup, with all 5 mortality cases in the aneurysmal subgroup presenting as World Federation of Neurological Surgeons (WFNS) grades ≥ III. 4 of the deaths were in WFNS IV and V patients. The most frequent perioperative complication was transient periorbital swelling which resolved within 7 days. It was observed in 18 of the 50 patients. The next common complications in descending frequency were eyebrow alopecia (three cases), supraorbital hypoesthesia (two cases), CSF leak (two cases), and surgical site infection (one case). There was one approach-related intraoperative complication secondary to carotid injury in a giant meningioma redo case. Conversion to a larger craniotomy was never necessary. Clinical outcome for our cases was evaluated according to the Modified Rankin Scale (mRS) at 3-month postsurgery. A good clinical outcome (mRS ≤ 2) was achieved for 78% of our patients. The SOE approach craniotomy is an effective minimally invasive approach for various pathologies of the anterior cranial base and parasellar regions. With experience, giant tumors and complex vascular pathology can be addressed with this keyhole approach.

Microvascular Reconstruction of the Anterior Skull Base.

Anterior skull base defects present a unique reconstructive challenge. Risk factors such as previous operation, radiation and infection require a multidisciplinary approach to create a stable wound. Reconstructive microsurgery serves an important role when attempts with pericranial flap placement and nonvascularized graft obliteration fail. Our series analyzes the outcomes of 5 patients who underwent vascularized reconstruction of craniofacial defects at Northwestern Memorial Hospital from 2014-2021. Each patient presented with a complex, hostile scalp and bony wound. Common risk factors included previous craniotomy, failed obliteration, chemoradiation, osteomyelitis and epidural abscess. Patients underwent multi-stage procedures to obtain wound source control, reconstruct the frontal sinus and skull base, and frontal bone cranioplasty. Each patient underwent successful free flap reconstruction without flap loss or donor site complications. No patients suffered ongoing symptomatic CSF leak or pneumocephalus. However, only two patients have had sustained success with their alloplastic cranioplasty. A perfect, watertight seal is required to prevent seeding the implant and avoiding infection. Overall, free flap reconstruction of the skull base and frontal sinus is a necessary solution when patients fail more conservative locoregional options. Close collaboration with neurosurgery can help with diagnosis and establish the optimal timing for surgical care.

Ethmoid roof morphometric measurements of a pediatric population using computed tomography.

To reveal the anatomical relationships of the ethmoid roof on CT in pediatric case group. We measured the depth of olfactory fossa (DOF), the width of olfactory fossa (WOF), the angle between lateral lamella and cribriform plate (LLCPA), the width of the olfactory cleft (WOC), the length of lateral lamella (LLL), orbital roof fovea to ethmoidal distance (ORFED) and orbital roof to cribriform plate distance (ORCPD) and we determined Keros and LLCPA types from paranasal sinus CT of subjects under 16years of age retrospectively. The incidence of Keros type I was higher in females and Keros Type II in males. The ORCPD, DOF and LLL values were found to be higher in 13-16years age group and WOF and LLCPA in 4-6years age group. The prevalence of Keros type II was higher in the 13-16 age group, and Keros type I was higher in other age groups. LLCPA type A was the most frequent in all age groups and in both sexes. There was a positive correlation between age and ORCPD, DOF, LLL, and a negative correlation with ORFED, WOF, LLCPA. Olfactory fossa width and depth had a negative correlation. LLCPA had a positive correlation with WOF and a negative correlation with DOF. There was a positive correlation between LLCPA and LLL. DOF and LLL had a positive correlation too. Paranasal sinus CT provides useful information about frontal skull base anatomic relations before sinus surgery in pediatric cases.

Phantom-based prospective analysis of the accuracy of photo registration technology in electromagnetic navigation of the frontal skull base.

This prospective study compared the accuracy of two different company-specific registration methods (Fiagon GmbH, Hennigsdorf, Germany) in the electromagnetic navigation of the frontal skull base. A newly developed photo registration technology (Fiagon tracey©) promises an increase in accuracy and user-friendliness, but there is no phantom-based prospective study comparing the new method with the classic approach of tactile surface registration. A phantom skull was prepared with 27 markers in the sagittal, axial and coronary planes, and their reference coordinates were determined using a navigational CT (low dose, slice 0.6 mm). Subsequently, 20 runs of automatic photo registration and tactile surface registration were carried out, and the resulting marker coordinates were compared with the reference coordinates. The target registration error (TRE) of the 27 markers was assessed and compared between the two methods using a 2-factor ANOVA with repeated measures. The mean TRE using surface registration was 1.97 mm ± 0.57, while the mean TRE of the automatic photo registration was 1.54 mm ± 0.24 (p < 0.001). In a subgroup analysis limited to markers in anatomical regions of clinical relevance in terms of paranasal sinus surgery, the mean TRE for the photo registration procedure can even be reduced to 1.29 mm (± 0.43) compared to tactile registration (1.80 mm; ±0.50; p=0.01). Photo registration is a promising new technology in the field of electromagnetic navigation in paranasal sinus surgery. This prospective phantom-based study showed that the photo registration method achieves a significantly lower target registration error (1.29 mm) compared to the surface-based tactile registration procedure (1.80 mm).

Computed Tomography Analysis of Nasal Anatomy in Dorsal Preservation Rhinoplasty.

Subdorsal septal resection and radix osteotomy are distinctive surgical steps in preservation rhinoplasty. The aim of this study was to evaluate the nasal bone thickness, the level of the septal bony-cartilaginous junction (K area), and the distances of the frontal sinus and skull base from the transverse osteotomy line in the Turkish population by means of conventional computed tomography (CT). A retrospective evaluation was made of 203 consecutive preoperative paranasal CT scans of patients (classified in terms of age and gender) who had undergone rhinoplasty surgery between January 2020 and June 2021. The nasal bone thickness at the medial canthus level, and the distances between the transverse osteotomy line and the K area, the frontal sinus, and the cribriform plate were measured. The mean measurements were similar in terms of age groups (P = 0.402, P = 0.542, P = 0.134 and P = 0.276 for ages 18-30, 30-40, 40-50, and >50 years, respectively). The mean nasal bone thickness and the distance between the transverse osteotomy line and the K area showed statistical significance (P = 0.001 and P = 0.001, respectively). In both genders, the mean distances between the transverse osteotomy line and the frontal sinus and the cribriform plate were similar (P = 0.921 and P = 0.280, respectively). The nasal bone was thinner and the K area position more cephalic in females. CT plays an important role in preoperative planning. The need for resection of the ethmoid perpendicular bone may be greater in males when lowering the dorsal hump, and hence they may be more prone to skull base complications. It is therefore necessary to be more careful in the surgical stage of subdorsal septal excision in males.

Cerebrospinal fluid may flow out from the brain through the frontal skull base and choroid plexus: a gold colloid and cadaverine injection study in mouse fetus

Cerebrospinal fluid may flow out from the brain through the frontal skull base and choroid plexus: a gold colloid and cadaverine injection study in mouse fetus

A third hand to the surgeon: the use of an endoscope holding arm in endonasal sinus surgery and well beyond

BackgroundExtended endoscopic endonasal operations of the sinuses and the frontal skull base require a bimanual action of the surgeon in many cases. Thus, typically an assistant guides the endoscope and centers the field of view. In this study, we investigate in which cases an endoscope holding arm can be used alternatively.Materials and methodsThe electromagnetic system ENDOFIXexo was used in different surgical interventions of the paranasal sinuses and beyond questioning ergonomics and geometrical limitations. The realized degrees of freedom were documented, and a topography of possible applications compiled.ResultsThe presented system is limited by the anatomy of the anterior ethmoid and dynamic working conditions in the sagittal direction. Especially in extended interventions in the posterior ethmoid, in which parts of the nasal septum have been resected and a static position of the endoscope is desired the surgeon can greatly benefit from the robotic arm. Moreover, through the high flexibility of the endoscopic arm surgeries of the pharynx and larynx were performed, questioning the current gold standard of microscope-assisted surgical procedures.ConclusionUnder the impression of an urging staff shortage and due to its unlimited patience, the ENDOFIXexo arm seems promising. Taking into account the complex anatomy and the limited access, we especially see a favorable field of application in the surgery of the pituitary gland and skull base tumors.

Investigation of factors that contribute to the outcome of endoscopic transsphenoidal surgery as reviewed from our own cases

In order to improve the treatment outcome of endoscopic transsphenoidal surgery (eTSS), it is important to identify the factors that contribute to the tumor resection rate and/or post-operative complications, and to devise a surgical strategy for each case. In the present study, we retrospectively evaluated our own experience of eTSS for primary pituitary adenoma (PA), and sought the factors that are related to patients’ surgical outcomes. Thirty-three cases of primary PA operated on by eTSS at our institution in a recent 5-year period were investigated. The patients’ data for age, sex, Knosp grade, operating time, sellar floor opening rate, tumor resection rate and post-operative complications were evaluated. The median rate of tumor resection was 91.3%, and the tumor resection rate demonstrated significant linear relationships with age (Z = −0.41, p = 0.02), sex (Z = −0.42, p = 0.01) and sellar floor opening rate (Z = 0.47, p = 0.01). A significant linear relationship was also found between sex and sellar floor opening rate (Z = −0.51, p < 0.01). However, post-operative cerebrospinal fluid (CSF) leakage occurred in 2 cases where the sellar floor was opened widely. We reviewed the details of these 2 cases in this article. The gender difference observed in this study results was thought to be due to the difference in size of the nostril; however, further verification is required. Although wide sellar floor opening can contribute positively to aggressive PA resection in eTSS, this may increase the risk of CSF leakage. If a case requires a higher resection rate, especially in functional PA invading the cavernous sinus, the surgeon should adopt and perform advanced techniques of sellar floor reconstruction according to those carried out in the expanded endonasal approach for the frontal skull base or clivus area.

Risk factors and predictive model of adrenocortical insufficiency in patients with traumatic brain injury.

Neuroendocrine dysfunction after traumatic brain injury (TBI) has received increased attention due to its impact on the recovery of neural function. The purpose of this study is to investigate the incidence and risk factors of adrenocortical insufficiency (AI) after TBI to reveal independent predictors and build a prediction model of AI after TBI. Enrolled patients were grouped into the AI and non-AI groups. Fourteen preset impact factors were recorded. Patients were regrouped according to each impact factor as a categorical variable. Univariate and multiple logistic regression analyses were performed to screen the related independent risk factors of AI after TBI and develop the predictive model. A total of 108 patients were recruited, of whom 34 (31.5%) patients had AI. Nine factors (age, Glasgow Coma Scale [GCS] score on admission, mean arterial pressure [MAP], urinary volume, serum sodium level, cerebral hernia, frontal lobe contusion, diffuse axonal injury [DAI], and skull base fracture) were probably related to AI after TBI. Three factors (urinary volume [X 4], serum sodium level [X 5], and DAI [X 8]) were independent variables, based on which a prediction model was developed (logit P= -3.552+2.583X 4+2.235X 5+2.269X 8). The incidence of AI after TBI is high. Factors such as age, GCS score, MAP, urinary volume, serum sodium level, cerebral hernia, frontal lobe contusion, DAI, and skull base fracture are probably related to AI after TBI. Urinary volume, serum sodium level, and DAI are the independent predictors of AI after TBI.

Case Report: A Rare Case of Penetrating Trauma of Frontal Sinus with Anterior Table Fracture

Head injury is common component of any road traffic accident injury. Injury involving only frontal sinus is uncommon and unique as its management algorithm is changing over time with development of radiological modalities as well as endoscopic intervention. Frontal sinus injuries may range from isolated anterior table fractures causing a simple aesthetic deformity to complex fractures involving the frontal recess, orbits, skull base, and intracranial contents. Only anterior table injury of frontal sinus is rare in penetrating head injury without underlying brain injury with history of unconsciousness and questionable convulsion which is new to existing literature.

Tension Pneumocephalus in a Tracheostomized, Chronically Ventilated, Duchenne’s Muscular Dystrophy Patient Without Prior Head Trauma

Tension pneumocephalus is a rare condition that can be a life-threatening neurosurgical emergency. It usually results from head trauma, but there have been case reports of iatrogenic causes including on non-invasive mechanical ventilation. We report a case of pneumocephalus resulting from high mechanical ventilation pressures in a patient without prior head trauma.A 37-year-old male with Duchenne’s muscular dystrophy who had been ventilator-dependent through tracheostomy was admitted for shortness of breath and intermittent fevers. The patient was found to have pneumonia, with left-lower lobe consolidation, and was started on linezolid given known Methicillin-resistant Staphylococcus aureus from previous sputum culture; he was later switched to vancomycin and piperacillin-tazobactam given persistent fevers to cover for hospital-acquired pneumonia. The patient went into septic shock requiring multiple pressors as well as stress steroids for persistent shock, with eventual improvement in hemodynamics. He developed further respiratory acidosis on his usual ventilator settings, and peak inspiratory pressures (PIPs) progressively increased to as high as 45-70 cm H2O during his hospital course. PIPs did not improve with suctioning or after bronchoscopy. On the 17th day of the patient’s stay, he had acutely altered mental status with non-reactive fixed and dilated pupils and disconjugate gaze of the right eye on neurologic examination. CT of the head at that time revealed extensive pneumocephalus along the bifrontal convexities, suprasellar cisterns, and posterior fossa, with a possible fracture of the frontal skull base near the ethmoid roof. Mount Fuji sign was present on CT scan, indicative of “tension pneumocephalus”. Neurosurgical consultation was obtained but the family declined intervention given his overall debilitated stated. Comfort measures were instituted, and the patient expired the following day.Pneumocephalus is the accumulation of air entry into the cranial cavity, generally from head trauma, inflammation, or surgery. Patients may have underlying base skull defects or microfractures that permit air to enter the intracranial cavity. Increased sphenoid sinus pressure from mechanical ventilation may enter the subperiosteal space, allowing air to enter the intracranial cavity. It is important to consider pneumocephalus in a patient with new neurological findings after mechanical ventilation.

High Mib-1-score correlates with new cranial nerve deficits after surgery for frontal skull base meningioma.

Postoperative new cranial nerve deficits comprise severe concomitant morbidity in skull base meningioma surgery. Therefore, long-term cranial nerve integrity represents an important outcome measure. In the current study, we analyzed our institutional database in order to identify risk factors for postoperative new cranial nerve morbidity in the course of frontobasal meningioma surgery. Between 2009 and 2017, 195 patients were surgically treated for frontobasal meningioma at the authors' institution. Postoperative cranial nerve function was assessed immediately after surgery as well as 12months postoperatively. A univariate and multivariate analysis was performed to identify factors influencing favorable postoperative cranial nerve outcome. Tumors with histological Mib-1-labeling indices > 5% were associated with a significantly higher percentage of new cranial nerve deficits immediately after surgery compared with those with Mib-1-labeling indices ≤ 5% (39% versus 20%, p = 0.029). Elevated Mib-1-labeling indices could be correlated with high CD68-positive macrophage staining (54% for Mib-1 index > 5% versus 19% for Mib-1 index ≤ 5%, p = 0.001). Elevated Mib-1-labeling index correlates with initial new cranial nerve dysfunction after resection of frontal skull base meningioma. With regard to elevated CD68-positive macrophage staining in high Mib-1-positive meningiomas, initial postoperative new cranial nerve morbidity might partly reflect macrophage-based inflammatory immune responses.

New landmarks in endonasal surgery: from nasal bone to anterior cribriform plate including branches of anterior ethmoidal artery and nerve and terminal nerve.

Despite the development of anterior skull base surgery, the anatomy of the nasal bone and anterior cribriform plate remains unclear. A recent study confirmed 2 distinct foramina in the anterior part of cribriform plate: the ethmoidal slit (ES) and the cribroethmoidal foramen (CF). The aim of this study was to specify their content, their anatomic relationship to the frontal sinus and skull base, and their potential value in skull base surgery. Dissections were performed on 36 cadaver heads. Macro- and microscopic examinations were carried out. Microcomputed tomography scans contrasted with osmium were performed to identify vessels and nerves. Histology with neural, meningeal, or luteinizing hormone-releasing hormone immunomarkers was performed on the content of the foramina. Finally, endonasal surgical dissections were carried out. The ES and the CF were observed in all cases. They measured a mean of 4.2 and 1.6 mm, respectively. The ES contained dura mater, arachnoid tissues, lymphatics, and the terminal nerve. The CF contained the anterior ethmoidal nerve and artery. This foramen continued forward with the cribroethmoidal groove,which measured a mean of 2.5 mm. This groove was under the frontal sinus and in front of the skull base. We also described a "cribroethmoidal canal" and a "nasal bone foramen." The clinical applications of this new anatomic description concern both cribriform plate and frontal sinus surgeries. Identifying the terminal nerve passing through the ES is a step forward in understanding pheromone recognition in humans.

Cranial Nerve Outcomes After Surgery for Frontal Skull Base Meningiomas: The Eternal Quest of the Maximum-Safe Resection with the Lowest Morbidity

Maximal aggressive meningioma resection has been suggested to provide the best tumor control rates. However, radical surgery of meningiomas located at the frontal skull base can be accompanied by impairment of adjacent cranial nerve function that negatively affects patients' quality of life. We, therefore, analyzed our institutional database for cases of new cranial nerve deficits and postoperative cerebrospinal fluid (CSF) leakage stratified by the extent of tumor resection. From February 2009 to April 2017, 195 patients underwent resection of frontal skull base meningioma at our institution. Postoperative new deficits of cranial nerve function and CSF leakage were stratified by the resection into Simpson grade I resection with excision of the dural tail as an aggressive surgical approach and Simpson grade II-V resection. Simpson grade I resection was associated with a significantly greater percentage of new cranial nerve deficits immediately after surgery (30%) compared with Simpson grade II (13%; P= 0.007) and Simpson grade II-V (17%; P= 0.035). The differences were greater at the 12-month follow-up point (29% Simpson grade I, 6% Simpson grade II [P < 0.001]; 10% Simpson grade II-V [P= 0.001]). Postoperative CSF leakage occurred in 10.1% of Simpson grade I versus 2.3% of Simpson grade II resections (P= 0.048). The retreatment rates did not differ between these 2 groups (2.5% vs. 3.4%; P= 1.000). We found high levels of new cranial nerve morbidity and CSF leakage after radical removal of frontal skull base meningiomas that included the adjacent dura. Thus, less aggressive surgery for frontobasal meningioma should be preferred.

Repair of Frontal Skull Base Defects in Children: Should a Transnasal Approach Always Be Attempted First?

Repair of Frontal Skull Base Defects in Children: Should a Transnasal Approach Always Be Attempted First?