Middle Cranial Base Research Articles

Anterior endoscopic sublabial transmaxillary access to middle cranial base lesions.

Anterior endoscopic access to middle cranial base lesions becomes feasible in the presence of infratemporal fossa (ITF) involvement. Various approaches, including endoscopic endonasal, transoral sublabial, and transorbital methods, have been described for accessing the ITF through a transmaxillary corridor. Among these approaches, endonasal access is the most commonly preferred, while the transorbital approach is a novel technique gaining popularity. The transoral sublabial approach is considered suitable for selected lesions. Patients who underwent the anterior endoscopic transoral/sublabial transmaxillary approach to middle cranial base lesions at a single institute from 2016 to 2023 were included in this retrospective study. Malignant lesions were excluded from the study. The sublabial approach was exclusively performed in all cases, with the exception of one patient who required a combined approach. The anterior endoscopic transoral sublabial transmaxillary approach to the infratemporal fossa, upper parapharyngeal space, and middle cranial fossa was performed on 14 patients. The underlying conditions for these patients were as follows: trigeminal schwannomas (n = 8), meningiomas (n = 2), juvenile nasopharyngeal angiofibroma, osteochondroma, arachnoid cyst and encephalocele (n = 1 each). Gross total resection was achieved in 11 cases. The most common complication was numbness in the territory of the maxillary and mandibular nerves (n = 4). Two patients needed endoscopic maxillary antrostomy for persistent suppuration. No wound problems or CSF rhinorrhea occurred. The average follow-up time was 26.6 months. The endoscopic sublabial transmaxillary approach provides direct access to the infratemporal fossa and middle cranial base, enhancing the surgical range of maneuverability while sparing the sinonasal cavity. This procedure is safe, less invasive, and could be used as an efficient corridor for the resection of selected infratemporal fossa lesions with or without extension to the middle cranial base and parapharyngeal space.

Three-Dimensional Analysis of the Cranial Base Structure in Patients with Facial Asymmetry.

Facial asymmetry is often seen in patients with skeletal mandibular prognathism and is associated with deformities in the maxillofacial and head regions. The maxillofacial deviation is three-dimensional and affects not only the lateral deviation of the mandible and midface, but also the cranium. This study conducted a three-dimensional morphological evaluation of the cranial base morphology of patients with skeletal mandibular prognathism (ANB < 0°, Wits < 0 mm) with the aim of examining the relationship between deformities of the head region and facial asymmetry. Data obtained from computed tomography conducted during the initial examination of patients with and without skeletal mandibular prognathism with facial asymmetry were used. Differences in the position of structures present in the cranial base were measured, and the association between cranial deformities and mandibular deviation was assessed. The middle cranial base area and the lateral deviation of the mandibular fossa were significantly larger in patients with facial asymmetry compared to those without facial asymmetry. In addition, a correlation between the amount of mandibular deviation and the area of the anterior cranial base was identified in patients with significant cranial deformity (p = 0.012). Given the identified association between the structure of the head region and facial asymmetry, further studies are needed to determine the factors implicated in the growth process.

Comparison of the transverse cranial base dimension in different craniofacial skeletal relationships: A cone-beam computed tomography study

Background/purposeIn comparing the cranial base's size, most cephalometric studies focused on the length and angle in the anteroposterior direction. However, investigating the anterior, middle, and posterior cranial base's transverse dimensions is challenging. This study aimed to investigate the transverse dimensions of the cranial base in different craniofacial skeletal patterns and sexes using cone-beam computed tomography (CBCT). Materials and methodsA total of 210 adults (105 males and 105 females), including three different skeletal relationships, were included in the study. The cranial base dimensions were measured on a three-dimensional image structure rendered by CBCT. Statistical methods included the Kappa statistic for analysis of consistency and reproducibility and the independent t-test for differences in cranial base dimensions between sexes. A general linear model (GLM) was used to compare the transverse size of the cranial base among skeletal Class I, II, and III groups. The Pearson correlation coefficient explored the correlation among the cranial base dimensions. ResultsThe cranial base dimensions did not differ significantly between skeletal Class I, II, and III. The more prominent cranial base size was found in males than females, except for the crista galli length (CGL) and cribriform ethmoid plate width (CEPW). The cranial base dimensions did not differ significantly between different skeletal relationships. Most dimensions have significant correlations in the middle and the posterior cranial base. ConclusionThe cranial base's transverse dimensions in Taiwanese adults show no significant differences between craniofacial skeletal relationships. In the middle and posterior cranial base, transverse measurements reveal significant sexual dimorphism.

Surgical Limitations of the Microscopic Transciliary Supraorbital Keyhole Approach to the Anterior and Middle Skull Base

The microscopic transciliary SupraOrbital keyhole (mtSO) approach has been used for a wide variety of anterior and middle fossa pathologies, including aneurysms, meningiomas, craniopharyngiomas, and other skull-base tumors. Several clinical series have proven its efficacy and safety, but detailed anatomical demarcations of the anterior and middle cranial base exposure are lacking. Our aim was to define the surgical limitations of the mtSO approach to the ipsilateral and contralateral anterior and middle skull base. Five cadaveric specimens (10 sides) were studied with image guidance to illustrate the limits of the surgical exposure. In addition, 30 dry skulls were used to measure the working distances between the craniotomy and key bony landmarks of the mtSO approach. Surgical exposure at the anterior skull base covered the area between the medial half of the contra- and the medial two-thirds of the ipsilateral sphenoid wing including both optic nerves and interoptic space. The anterior limit at the midline was the sphenoethmoidal suture. Ipsilateral anterior clinoidectomy permitted exposure of the superior orbital fissure, which defined the anteromedial limit at the middle fossa, whereas the anterolateral limit was defined by the ophthalmic branch of the trigeminal nerve. Moreover, the posteromedial and posterolateral limits were the posterior clinoid process and the petrous ridge, respectively. Our findings define the surgical limitations of the mtSO approach for the treatment of anterior and middle cranial base pathologies. These limits can be reliably identified on imaging studies allowing assessment of exposure to guide preoperative case selection.

Craniofacial development in patients of Tessier No.0 cleft with a bifid nose using 3D computed tomography.

ObjectiveConsiderable studies have focused mainly on the facial deformity of Tessier No.0 cleft with a bifid nose, but the deformity of the skull is not well understood. Therefore, our study aimed to explore the evolution of cranial dysmorphology and the chronology of Tessier No.0 cleft with a bifid nose, by three-dimensional measurements.MethodsNinety-six non-surgical patients and computed tomographic scans were included (Tessier No.0 cleft with a bifid nose, n = 48; controls, n = 48) and divided into five age subgroups. Craniofacial cephalometric measurements were analyzed by Mimics software.ResultsThe widening of nasal bone was the most remarkable and persistent from 2 years old appropriately. The overall cranial base length in patients compared with controls increased 11.8% (p < 0.01) on average. The middle and posterior cranial fossa increasing accounted for most of this change. The cranial base angles also showed increased obviously. By analyzing the linear of the nasopharynx and respiratory tract, it was found that its development did not affect respiration.ConclusionsThe cranial base deformity of Tessier No.0 cleft with a bifid nose consists of the whole skull base and particularly the middle and posterior cranial base length increase. At the same time, there may be late closure of the spheno-occipital synchondrosis and sella displacement. We believe this study is unique in providing valuable data for elucidating the pathological and morphological abnormalities of skull base development in Tessier No.0 cleft with a bifid nose.

Orbital Actinomycetoma with cranial extension: A rare case report.

IntroductionMycetoma is a neglected tropical disease that commonly affects the lower extremity. The disease is attributed to subcutaneous granulomatous inflammation leading to distinct clinical features of gradual painless swelling accompanied by nodules and drains. Orbital mycetoma is an extremely rare entity of the disease. We reported the clinical presentation, diagnosis, and surgical outcomes in a case of orbital mycetoma with cranial extension.Case presentationA 25-years-old male complained of left eye protrusion for 8 years, followed by complete loss of vision on the left eye for 7 years and eventually left eye pain for the last year. The left eye was displaced anteriorly and inferiorly with normal oculomotor, abducent, and trochlear examination. Brain CT scan showed an increase in orbital bone thickness with extension to the anterior cranial base, middle cranial base, and the orbital process of the zygomatic bone. MRI revealed a large lesion involving the left frontotemporal region with extension to left orbit, left posterior ethmoid air cells, and left temporal suprasellar region. The lesion was homogenously enhanced with contrast. The patient underwent a left orbitozygomatic cranitomy for resection of the lesion. However, total resection was inapplicable due to the extension of the bony lesion up to the petrous bone. Cranioplasty was performed by titanium mesh.ConclusionMycetoma is a chronic inflammatory disease affecting subcutaneous tissues commonly in the lower limbs. The disease can be caused by fungi (Eumycetoma) or bacteria (Actinomycetoma). Orbital mycetoma is an extremely rare entity of the disease. However, it is commonly associated with the cranial extension. Early diagnosis and prompt surgical and medical treatment are the keys to good outcomes.

Reliability of Different Anterior Cranial Base Reference Areas for Voxel-Based Superimposition.

The study aimed to evaluate the reliability and reproducibility and compare the outcomes of two 3D voxel-based superimposition techniques for craniofacial CBCT images, using anterior cranial base areas of different extent as references. Fifteen preexisting pairs of serial CBCTs (initial age: 11.7 ± 0.6 years; interval: 1.7 ± 0.4 years) were superimposed on total anterior cranial base (TACB) or middle anterior cranial base (MACB) structures through the Dolphin 3D software. The overlap of the reference structures was assessed visually to indicate reliability. All superimpositions were repeated by the same investigator. Outcomes were compared to assess the agreement between the two methods. Reliability was perfect for the TACB and moderate for the MACB method (p = 0.044). Both areas showed good overall reproducibility, though in individual cases there were notable differences for MACB superimpositions, ranging from −1.84 to 1.64 mm (TACB range: −0.48 to 0.31 mm). The overall agreement in the detected T0/T1 changes was also good, though it was significantly reduced for individual measurements (median < 0.01 mm, IQR: 0.46 mm, range: −2.81 to 0.73 mm). In conclusion, the voxel-based superimposition on TACB was more reliable and showed higher reproducibility than the superimposition on MACB. Thus, the extended anterior cranial base area is recommended for the assessment of craniofacial changes.

The endoscopic prelacrimal recess approach to the paramedian middle cranial base: An anatomical study

BackgroundEndoscopic endonasal approach to paramedian cranial base implies sacrifice of the nasal structures. ObjectiveThe present study aimed to illustrate the anatomy and provide critical anatomical landmarks for the endoscopic prelacrimal recess approach (PLRA) to the paramedian middle cranial base. MethodsAnatomical dissections were performed in 10 cadaveric specimens. ResultsSuccessful access to the paramedian middle cranial base was achieved in all dissections via the PLRA with the removal of the pterygoid process. For the dissection of the infratemporal fossa and pterygopalatine fossa, the buccal nerve and infraorbital neurovascular bundle can serve as important anatomic landmarks to identify the detailed structures. In the upper parapharyngeal space, the stylopharyngeal aponeurosis can present as anatomical barriers to protect the parapharyngeal segment of the internal carotid artery (PPICA); while the levator veli palatini muscle can be considered as a landmark to locate the PPICA. For the dissection of the Eustachian tube (ET), the isthmus of the ET and ET sulcus can serve as useful landmarks to identify the posterior genu of the ICA and horizontal segment of the petrous ICA respectively. ConclusionThe PLRA to the paramedian middle cranial base is anatomically feasible and can facilitate preservation of the integrity of nasal structures. The buccal nerve, infraorbital neurovascular bundle, levator veli palatini muscle, stylopharyngeal aponeurosis, the isthmus of the ET, and ET sulcus can serve as critical anatomic landmarks in their respective region and may facilitate the application of this approach.

Maxillary swing approach - Sri Lankan experience

Introduction:The maxillary swing approach is one of the trans maxillary surgical approach techniques used in otorhinolaryngology. It gives wide exposure to the nasopharynx, orbital apex, sphenoid sinus pterygopalatine fossa, infra temporal fossa and middle cranial base. This enables en bloc resections of tumour and proper visualization. Objectives:To study patients who underwent this procedure during the last five years with regard to indication, technique, and complications.To compare our patient outcomes with the published literature.To identify the factors leading to complications with recommendations to reduce them in the future.Methods:Retrospective analytical study was done on patients operated from 2015 to 2020 at the ENT Unit C of the National Hospital of Sri Lanka (NHSL).Results:A total of 14 patients underwent maxillary swing approach during the study period. The most common indication was angiofibroma. About 28% had an unacceptable scar following the surgery, which was the most occurring complication while 2 patients had recurrences during this period.Conclusion:Maxillary swing is a useful surgical approach with no major complications in our series. Commonest complication was an unacceptable scar (28%). Other complications were palatal fistula and nasal speech. It is postulated that further refinement of the technique will reduce these complications.

Https://dergipark.org.tr/tr/download/article-file/1328425

Objective: Supratrochlear and infratrochlear triangles are surgical corridors for approaching the lateral wall of the cavernous sinus. The literature provides conflicting results for the morphology and morphometry of these triangles. Additionally, the possible effects of vascular structures that drain into the cavernous sinus in unknown. This study aimed to investigate the morphology, morphometry, and vascular relationships of the supratrochlear and infratrochlear triangles of the cavernous sinus. Material and Method: Cranial bases of 25 cadavers were dissected bilaterally under a surgical microscope. Five of the cadavers were injected with colored silicone for vascular evaluation. The morphology of supratrochlear and infratrochlear triangles were classified according to the course of the trochlear nerve. Photogrametric measurements were used for evaluating the areas of both triangles with the ImageJ software. The triangular morphology was also investigated in regard to the drainage patterns of the superficial middle cerebral vein and cranial base dural sinuses. Results: Type A, B, C, and D triangle morphology was present on 23 (46%), 9 (18%), 10 (20%), and 8 (16%) sides, respectively. The average areas for supratrochlear and infratrochlear triangles were 22.2 (±11.7) mm2 and 78.4 (±27.7) mm2 , respectively. The supratrochlear triangle was significantly larger in Type D triangles. On 71.4% of injected specimens, the superior petrosal sinus contributed the cavernous sinus and formed a Type A triangle. Conclusion: The anatomy of the supratrochlear and infratrochlear triangles are highly variable than previously reported. Introducing the knowledge regarding these variations to neurosurgical residency education programs and daily surgical practice could be valuable.&nbsp;

Racial Disparity of Crouzon Syndrome in Skull and Orbit Morphology, and Their Spatial Relationships

BACKGROUND: Racial disparity in pathological consequences in skull and orbit growth may impact the treatment plan for different patient populations. This study explores skull anatomy for potential differences between Asian and Caucasian cranial morphology in Crouzon syndrome. METHOD: Ninety-one computed tomographic scans were included (Asian Crouzon, n = 12; Asian controls, n = 22; Caucasian Crouzon, n = 16; Caucasian controls, n = 41), and measured using Mimics and 3-matics software. Unique cephalometric measurements related to the orbit were designed. RESULTS: The entire cranial base length was reduced 11.92 mm (P = 0.004) in Asian Crouzon patients, and 14.58 mm (P < 0.001) in Caucasian Crouzon patients, compared with respective controls. The cranial base angle on the facial side of basicranium was more narrowed in Crouzon syndrome in both races, with similar changes of degrees (9.61°, P = 0.002, in Asian Crouzon; 9.20°; P = 0.019, in Caucasian Crouzon). However, the intracranial side was statistically more narrowed only in the Asian group (9.86°; P = 0.003). Both Asian and Caucasian Crouzon patients developed reduced posterior fossa volume, by 15% (P = 0.034) and 17% (P = 0.004), respectively. However, Caucasian Crouzon patients developed a more shortened anterior and middle cranial base than that of Asian patients. The separation of lateral pterygoids was only significantly increased in Caucasian patients (5.49°; P < 0.001). The orbital roof anteroposterior length of Caucasian Crouzon syndrome patients was shortened by 4.03 mm (P = 0.009) compared with Caucasian controls. However, this dimension in Asian patients developed normally. The orbital anteroposterior floor length significantly reduced in both Asian and Caucasian Crouzon syndrome patients, to a similar extent. The medial horizontal angle of single orbit was narrower in Asian patients, compared with Asian controls (19.24°; P = 0.002), yet only insignificantly reduced in Caucasian patients. The visual axes of Caucasian Crouzon syndrome patients had more inferior rotation, by 5.21° (P = 0.005) than in Caucasian controls but did not achieve a statistically significant difference in other comparison pairs. A widened ethmoid sinus is the major shortening in the restricted orbit cone angle in Asian Crouzon syndrome patients, while statistically significant widening of the sphenoid is noted only in Caucasian patients. CONCLUSION: The influence of Crouzon syndrome on cranial and orbital malformation is race influenced. Asian Crouzon patients developed more kyphotic basicranium evaluated intracranially, whereas Caucasian Crouzon patients developed more widened lateral pterygoid bones. The unaffected orbital roof length and shortened orbital floor in Asian Crouzon syndrome patients indicates the Lefort III osteotomy probably is more beneficial in this group of patients than in monobloc advancement.

Racial Disparity Between Asian and Caucasian Crouzon Syndrome in Skull Morphology.

Racial disparity in pathological consequences in skull growth may impact the treatment plan for different patient populations. This study attempts to explore the differences between Asian and Caucasian cranial morphology in Crouzon syndrome. Ninety-one computed tomographic scans were included (Asian Crouzon syndrome, n = 12; Asian controls, n = 22; Caucasian Crouzon syndrome, n = 16; Caucasian controls, n = 41), and measured using Mimics and 3-matics software. The entire cranial base length was reduced 11.92 mm (P = 0.004) in Asian Crouzon patients, and 14.58 mm (P < 0.001) in Caucasian Crouzon patients, compared to respective controls. The cranial base angle on the facial side of basicranium was more narrowed in Crouzon syndrome in both races, with similar changes of degrees (9.61°, P = 0.002, in Asian Crouzon; 9.20°, P = 0.019, in Caucasian Crouzon). However, the intracranial side was statistically more narrowed only in the Asian group (9.86°, P = 0.003). Both Asian and Caucasian Crouzon patients developed reduced posterior fossa volume, by 15% (P = 0.034) and 17% (P = 0.004), respectively. However, Caucasian Crouzon patients developed a more shortened anterior and middle cranial base, than that of Asian patients. The separation of lateral pterygoids was only significantly increased in Caucasian patients (5.49°, P < 0.001). Crouzon syndrome causes a shortened, widened, and kyphotic cranial base across both races. It also restricts the development of the posterior cranial fossa. However, the skull malformation is not the same between populations: Asian Crouzon patients developed more narrowed cranial base angulation on the intracranial side of basicranium, while Caucasian Crouzon patients developed more widened lateral pterygoids.

Anatomy of the Orbit.

The orbit is a paired, transversely oval, and cone-shaped osseous cavity bounded and formed by the anterior and middle cranial base as well as the viscerocranium. Its main contents are the anterior part of the visual system, globe and optic nerve, and the associated neural, vascular, muscular, glandular, and ligamentous structures required for oculomotion, lacrimation, accommodation, and sensation. A complex stream of afferent and efferent information passes through the orbit, which necessitates a direct communication with the anterior and middle cranial fossae, the pterygopalatine and infratemporal fossae, as well as the aerated adjacent frontal, sphenoidal, and maxillary sinuses and the nasal cavity. This article provides a detailed illustration and description of the microsurgical anatomy of the orbit, with a focus on the intrinsically complex spatial relationships around the annular tendon and the superior orbital fissure, the transition from cavernous sinus to the orbital apex. Sparse reference will be made to surgical approaches, their indications or limitations, since they are addressed elsewhere in this special issue. Instead, an attempt has been made to highlight anatomical structures and elucidate concepts most relevant to safe and effective transcranial, transfacial, transorbital, or transnasal surgery of orbital, periorbital, and skull base pathologies.

Clinical analysis of complications of suppurative otitis media in children

Objective:To summarize and analyze the clinical manifestations and surgical treatment for complications of suppurative otitis media in children. Method:The characteristic of 35 children under 14 years old with suppurative otitis media who had no response to conservative treatment were analyzed retrospectively. Of the patients, 23 cases（65.7%） with subperiosteal abscess, 7 cases （20.0%） with peripheral facial paralysis, 2 cases（5.7%） with brain abscess, 1 case（2.9%） with Bezold abscess, 1 case（2.9%） with labyrinthitis, 1 case （2.9%） with sigmoid sinus thrombophlebitis. Thirty cases（85.7%） were less than 5 years old. The operation methods included mastoidotomy（17 cases）, mastoidotomy combined with grommet insertion（12 cases）, canal wall up mastoidectomy（4 cases）, canal wall down mastoidectomy（2 cases）. Result:CT examination showed that 6 cases of middle ear infection complicated with extensive bone destruction in mastoid process, middle cranial fossa base and auditory ossicles. The severity of hearing loss was positively correlate to the presence of auricular meatus purulence（P<0.05）, but not to the onset time of hearing loss, disease duration and the bacteria species（P>0.05）. After a 6 months postoperative follow-up, all the wounds were well recovered. 26 patients received audiology tests at 3 months after operation, 18 cases with normal hearing or mild conductive hearing loss preoperatively had normal hearing after operation, 2 cases with moderate conductive hearing loss had a 10-15 dB HL increase in air-bone gap after operation,hearing reconstructions surgery was not performed in 1 case of severe mixed hearing loss and 1 case of moderate conductive hearing loss due to serious damage in the middle ear structure, therefore no significant improvement in hearing in these two cases,four cases with extremely severe hearing loss before the operation had no hearing improvement, while nine cases did not provide the hearing results. Conclusion:The symptoms of otitis media in children were not obvious while the complications could be severe, especially in younger children. Repeatedly auricular meatus purulence may indicate hearing impairment. Microbiological examination should be conducted at the early stage, and prompt treatment should be performed based on hearing and temporal bone CT scan to prevent irreversible complications and sensorineural hearing impairment.

Use of Digitally Annotated and Printed 3D Models for Teaching the Pterygopalatine Fossa

Anatomically deep and geometrically complex regions are difficult for students to visualize in gross dissections, overly simplified in models, and not faithfully depicted in 2D images. One such region is the pterygopalatine fossa which communicates with the infratemporal region, middle cranial fossa, cranial base, nasal and oral cavities, and face via 7 osteological foramina or fissures. Given the geometric complexity of this space, we aimed to create a 3D based educational tool for students to use in their pre‐clinical, dissection‐free head and neck anatomy course.A cranium rendered from CT imaging was imported into Medium, a digital sculpting program, using the Oculus Virtual Reality (VR) system. The right half was removed, and the left half was divided into three sections via two parasagittal slices. The lateral parasagittal cut bisected the foramen rotundum and palatine canals, and the medial parasagittal cut bisected the left half of the nasal cavity. The only alterations to the morphology was an exaggeration of the palatine canal and the anterior and posterior openings of the Vidian canal to allow for the passage of wires during the lab exercise. The three sections of the cranium were then 3D printed. In addition to 3D printing, the model was annotated in Medium by drawing in the course of the maxillary artery and nerve and their branches, and the nerve of the Vidian canal in the pterygopalatine fossa and associated regions. The model showing the neurovasculature related to the pterygopalatine fossa was imported into Sketchfab, a 3D model publishing platform, where labels could be placed to identify structures and provide additional information. The labeled model was embedded into the digital lab manual for students to reference during the lab activity where they were directed to pass a wire through the various foramina and fissures in the region to understand the passage of the neurovasculature in and out of the pterygopalatine fossa.The annotated digital model allowed students to visualize the completed course of these nerves and arteries while the printed model gave appreciation for the location, size, and orientation of the canals and foramina through which the pterygopalatine fossa communicates with other regions. This intervention was applied in the 2019 Living Anatomy: Head and Neck course, where students did not perform dissection but did have access to prosected cadavers and plastinations.Student performance on the 2019 exam was statistically identical to the performance of previous cohorts in a traditional dissection‐based anatomy course (2018: 85.9%; 2019: 88.1%). The 2019 cohort on average scored lower on questions derived from the material from the lab that included this intervention compared to the 2018 cohort (2018: 84.82%; 2019: 80.76%). However, the pterygopalatine fossa question (97.09%) outperformed the nasal cavity (80.58%) and larynx/pharynx (78.5%) questions. Additionally, students ranked digitally annotated 3D models the 3rd highest activity or resource following faculty directed case studies and the prosected cadavers. Student exam results and feedback indicate a utility of providing physical objects with digital 3D reference material during anatomy instruction.

Paranasal Sinus Wall Erosion and Expansion in Allergic Fungal Rhinosinusitis: An Image Scoring System

BackgroundBone erosions are common in allergic fungal rhinosinusitis (AFRS). This study aimed at developing an image-based grading and scoring system for paranasal sinus (PNS) wall erosion in AFRS.MethodsA retrospective review of all confirmed AFRS cases based on the Bent and Kuhn criteria was conducted. Preoperative computed tomography (CT) images were studied to detect PNS wall erosion with expansion. Based on our observation, we described a grading system based on the proportion of PNS wall erosion, with 1 if less thanone-third, 2 if between one-third and two-thirds, and 3 if more than two-thirds of the wall is eroded. This method provides a new scoring system ranging from 0 to 72. The inter-observer reliability of this scoring system was tested and the percent of agreement was found to be 90%.ResultsAmong 142 AFRS cases, 82 patients (57.7%) had bone erosion. Orbital extension via lamina papyracea erosion occurred in 28.2% and 17.6% of the anterior and posterior ethmoid sinuses respectively, via floor erosion in 8.3% of the frontal sinuses, and via roof erosion in 2.1% of the maxillary sinuses. Intracranial extension caused by the anterior skull base erosion occurred in 19.4%, 10.9%, and 6% of the posterior ethmoid, anterior ethmoid, and frontal sinuses, respectively. The middle and posterior cranial fossa skull base was eroded in 14.4% and 9.2% of the sphenoid sinuses, respectively. Infratemporal extension occurred via erosion of the sphenoid sinus lateral wall in 17.3% of the sphenoid sinuses and via erosion of the maxillary sinus posterior wall in 6.7% of the maxillary sinuses. The mean of bone erosion score was 9.52, and the highest score was 34/72.ConclusionThe orbit is the most common extra-sinus extension site via the lamina papyracea erosion. We propose a new grading and scoring system to assess disease severity and progress.

Utility of the Midface Degloving Approach for Extended Exposure in Maxillary Pathologies.

A generous exposure of the midface region is essential for a comprehensive and thorough execution of midface surgical procedures, especially bilateral procedures. Traditional approaches to the midface the midface like the lateral rhinotomyand Weber-Fergusson/Dieffenbach incision with their modifications leave a visible scar, andthey are limited in their unilateral exposure. The midface degloving approach with its exclusive intranasal and intraoral incisions leaves no external scars and lends excellent bilateral exposure of the maxilla, zygoma, paranasal areas andinfraorbital margins from one side to the other. The midface degloving approach is mainlyused to expose pathologies of the maxilla, nasal cavities, paranasal sinuses, nasopharynx, and the central compartment of the anterior and middlecranial base. This approach can also be used to treat midface trauma and performhigh-level osteotomies. We describe the midface degloving procedure for nine cases operated in the Department of Oral and Maxillofacial Surgery over a period of 7years (2012-2018): seven maxillary tumors and two maxillary cysts. We obtained excellent exposure for all the cases using this approach. Complications included mild distortion of the lowerlateral nasal cartilages and oro-nasal communication. The midface degloving approach lends excellent surgical access to the midfacial skeleton including the maxilla, the paranasal areas, the maxillary sinus, the zygoma, and infraorbital rims. The advantages of this approach besides its generous exposure, is the excellent cosmesis it provides leaving no external scars.

Feasibility of Bundled Payments in Anterior, Middle, and Posterior Cranial Fossa Skull Base Meningioma Surgery: MarketScan Analysis of Health Care Utilization and Outcomes

The aim of our study was to compare the health care utilization and outcomes after surgery for anterior cranial fossa skull base meningioma (AFM), middle cranial fossa skull base meningioma (MFM), and posterior cranial fossa skull base meningioma (PFM) across the United States. We queried the MarketScan database using International Classification of Diseases, Ninth Revision and Current Procedural Terminology 4, from 2000 to 2016. We included adult patients who had at least 24 months of enrollment after the surgical procedure. The outcome of interest was length of hospital stay, disposition, complications, and reoperation after the procedure. A cohort of 1191 patients was identified from the database. Less than half of patients (43.66%) were in the AFM cohort, 32.24% were in the MFM cohort, and only 24.1% were in the PFM cohort. Patients who underwent surgery for PFM had longer hospital stay (P= 0.0009), high complication rate (P= 0.0011), and less likely to be discharged home (P= 0.0013) during index hospitalization. There were no differences in overall payments at 12 months and 24 months among the cohorts. There was no significant difference in 90-day median payments among the groups ($66,212 [AFM] vs. $65,602 [MFM] and $71,837 [PFM]; P= 0.198). Male gender, commercial insurance (compared with Medicare), and higher comorbidity scores (score 3 compared with score 0) were associated with higher 90-day payments in the PFM cohort. Overall payments (at 12 months and 24 months) and 90-day payments were not different among the cohorts. Patients with PFM had longer hospital stay and higher complication rate and were less likely to be discharged home with higher utilization of outpatient services at 12 months and 24 months.

Diploic veins of the cranial base: an anatomical study using magnetic resonance imaging.

The anatomy and distribution of the diploic veins (DVs) of the cranial base have not been fully documented. The aim of this study was to characterize these veins using contrast magnetic resonance imaging (MRI). In total, 95 patients underwent thin-sliced, contrast MRI. Coronal and sagittal images were used for the analysis. The cranial base was divided into the anterior, middle, and posterior bases. Then, each base was further subdivided into three equal parts in the anteroposterior and lateromedial directions. The anteroposterior parts were evaluated on coronal images, while the lateromedial parts were evaluated on sagittal images. The DVs were identified over the entire cranial base. However, they were more frequent in the posterior-third of the lateral-third region of the anterior, middle-third of the lateral and middle-third regions of the middle, and middle-third region of the posterior cranial base, and sparse in the posterior and medial-third regions of the middle cranial base. The DVs showed marked morphological variability. For instance, the DVs of the pterional area were generally well defined, as pivotal channels connecting the lateral parts of the anterior and middle cranial base, but were highly varied in appearance. The DVs of the cranial base are distinct structures characterized by morphological variability and topographical predilection. Contrast MRI is useful for delineating these veins.

Pure Endoscopic Surgery via Subtemporal Extradural Keyhole Approach for Middle Cranial Fossa Tumors

Extradural subtemporal keyhole approach could provide adequate removal for some specific middle skull base tumors. The combination of endoscopy and keyhole technique might further help to minimize the complications and provide optimal surgical visualization. Here, a series of attempts with endoscopy by mini-invasive subtemporal extradural approach for 5 middle skull base tumors were successfully achieved. From November 2015 to November 2018, resections of 5 cases of middle cranial fossa tumors were performed with pure endoscopy via subtemporal extradural keyhole approach. Patient medical records, imaging data, surgical procedures, pathology results, and follow-up outcomes were collected and analyzed. Adequate extradural subtemporal space was successfully established for endoscopy, and tumor resection was performed. Postoperative pathology confirmed cholesteatoma, cholesterol granuloma, schwannoma, granuloma, and osteoblastoma, respectively. Two patients with osteoblastoma and granuloma received subtotal resection, and the other 3 achieved total resection. One patient suffered from brain edema and was relieved after systematic mannitol treatment. No other complications were observed, and no progression was found during follow-up. This exploratory series demonstrated the safety and effectiveness of pure endoscopic surgery via subtemporal extradural route for satisfactory middle cranial base tumor resection.