Petrous Bone Research Articles

Objective: Retrosigmoid approach and presigmoid approach and its derivatives including retrolabyrinthine, translabyrinthine, and transpetrosal approaches have long been used for reaching posterior and middle cranial fossa. In neurosurgery perspective, many types of tumors arise extradurally and surgical resection of these tumors is still challenging. We aimed to describe a modified way to approach posterior and middle fossa to contribute to the surgical management of petroclival tumors with posterior extension. Methods: Modified sigmoid approaches were performed bilaterally in 5 fresh adult cadaver heads. Results: In this approach, it was possible to reach the middle and posterior fossa with a single craniotomy. Temporal dura matter was dissected from the temporal bone with extradural gentle dissection. In addition, sigmoid sinus and superior petrosal sinus (SPS) were dissected off from the petrous bone meticulously. Subsequently, the posterolateral superior arcuate petrosectomy was performed with high-speed surgical drill extradurally by protecting the semicircular canal, labyrinthine channel, and cochlea. Dura matter was elevated for 1.5 cm with retractor above the mastoid bone. Dura was opened from an alternative area of Trautmann’s triangle. After having exposed and opened the dura, posterior fossa was reached at the level of 7.−8. cranial nerves. Conclusion: We described an alternative route which seems to be a feasible way to reach posterior and middle fossa without mastoidectomy and SPS ligation. Notably, this technique can be applicable to petroclival tumor surgery after more anatomic studies with cadaveric specimens.

Introduction: The head and neck region is a very uncommon location for small cell neuroendocrine carcinomas (SCNEC), which are notoriously aggressive and have a terrible prognosis. We describe the second case of a poorly differentiated SCNEC involving the petrous apex of the temporal bone in the literature and discuss its therapy. Case Summary: A 42-year-old white male smoker, without personal or familial significant history, presented with right-sided otalgia. A transnasal endoscopic biopsy of the right apical petrous bone was performed and the histopathological analysis was consistent with poorly differentiated SCNEC. The patient received 4 cycles of systemic chemotherapy followed by 30 radiotherapy sessions. Brain magnetic resonance imaging, positron emission tomography scan, and whole-body computed tomography scan images confirmed the absence of metastatic focus. Discussion: The literature lacks enough documentation of treatment regimens for head and neck SCNECs. The biggest difficulty in our management is that few studies advise combining radiotherapy and chemotherapy without surgery.

Facial nerve schwannomas account for about 0.8% of all petrous mass lesions. Schwannomas of the greater superficial petrosal nerve (GSPN) are a rare subtype with few case-reports up to date. A retrospective analysis of clinical outcomes, radiographic findings and postoperative complication between June 2007 and December 2020 was performed. Four cases of GSPN schwannomas were reported. The presenting symptoms were facial nerve palsy and hearing loss. Imaging studies showed a subtemporal mass on the anterosuperior aspect of the petrous bone, in one case with extraordinary petrous bone and mastoid infiltration and destruction. Three cases were removed through a subtemporal extra- or intradural approach, one case via a combined pre- and retrosigmoid approach. Improvement of facial nerve palsy occurred in one case; new hearing loss was observed in another case. Xeropthalmia was a short-term temporary deficit in three cases. Short- to mid-term follow-up of the patients has not shown any tumor recurrence. GSPN schwannomas are rare entities presenting with heterogenous symptoms. Our surgical findings emphasize safe resection. Complete remission is possible by GTR. Since the small data set limits the expressiveness of statements regarding standard of care and alternative therapy options, additional data is needed.

Petrous bones and teeth are the skeletal elements most often targeted by researchers for ancient DNA (aDNA) extraction, and the sources of the majority of previously published ancient African genomes. However, the high temperature environments that characterise much of Africa often lead to poor preservation of skeletal remains. Here, we successfully reconstruct and analyse genome-wide data from the naturally mummified hair of a 4000-year-old individual from Sudan in northeastern Africa, after failed attempts at DNA extraction from teeth, petrous, and cranium of this and other individuals from the Kadruka cemeteries. We find that hair DNA extracted with an established single-stranded library protocol is unusually enriched in ultra-short DNA molecules and exhibits substantial interior molecular damage. The aDNA was nonetheless amenable to genetic analyses, which revealed that the genome is genetically indistinguishable from that of early Neolithic eastern African pastoralists located 2500 kms away. Our findings are consistent with established models for the southward dispersal of Middle Nile Valley pastoral populations to the Rift Valley of eastern Africa, and provide a possible genetic source population for this dispersal. Our study highlights the value of mummified hair as an alternate source of aDNA from regions with poor bone preservation.

Recent improvements in the analysis of ancient biomolecules from human remains and associated dental calculus have provided new insights into the prehistoric diet and genetic diversity of our species. Here we present a multi-omics study, integrating metagenomic and proteomic analyses of dental calculus, and human ancient DNA analysis of the petrous bones of two post-Last Glacial Maximum (LGM) individuals from San Teodoro cave (Italy), to reconstruct their lifestyle and the post-LGM resettlement of Europe. Our analyses show genetic homogeneity in Sicily during the Palaeolithic, representing a hitherto unknown Italian genetic lineage within the previously identified Villabruna cluster. We argue that this lineage took refuge in Italy during the LGM, followed by a subsequent spread to central-western Europe. Analysis of dental calculus showed a diet rich in animal proteins which is also reflected on the oral microbiome composition. Our results demonstrate the power of this approach in the study of prehistoric humans and will enable future research to reach a more holistic understanding of the population dynamics and ecology.

To review the literature on Hyrtl fissure (HF) and contribute our experience with a 2-year old who developed cerebrospinal fluid (CSF) otorrhea during routine tympanostomy tube placement. Data Sources: Pubmed and Google Scholar searches were conducted of articles in the English language literature from all time periods using the words Hyrtl, Hyrtl's fissure, HF, and tympanomeningeal fissure. Study Selection: All relevant articles were reviewed to identify cases of HF. Data Extraction: Nineteen cases, including ours, are described. Patient characteristics, method(s) of diagnosis and repair, and outcomes are reported. Computed tomography and intraoperative endoscopic images from our case are included. Presentation is more common in children (66.7% of cases where age was stated, n = 10) than in adults (33.3%, n = 5), and is most commonly unilateral (89.5%, n = 17). Cerebrospinal fluid otorrhea was the most common presentation. Six were discovered after tympanostomy tube placements while 3 were identified during cochlear implant work-up or after device failure. Surgical approaches described include endaural, transcanal, retrosigmoid, postauricular, and posterior fossa endoscopic. Multiple materials including bone wax, bone pate, fascia, muscle, and tissue sealant have been used. Our case describes an endoscopic repair in a child, which was successful at a 2-year follow-up. Data Synthesis: The small number of cases limits the utility of statistical analysis (n = 19). Hyrtl fissure is a rare but important entity that may be discovered when routine procedures have unexpected results. Hyrtl fissure should be included in the differential diagnosis when there is persistent clear otorrhea after a tympanostomy tube, cochlear implant misinsertion, meningitis, or unexplained middle ear effusion in an adult.

Endoscopic Endonasal Transpterygoid Approach for Resection of Carotid Sympathetic Plexus Schwannomas: A Cadaveric Stepwise Dissection, Technical Nuances and Surgical Outcomes

Background:The role of imaging in cholesteatoma continues to evolve with excellent bony details provided by high-resolution computed tomography and high soft tissue identification for cholesteatoma by diffusion-weighted magnetic resonance imaging. The fusion of high-resolution computed tomography and diffusion-weighted magnetic resonance imaging combines the advantages of both imaging techniques.Methods:A random sample of 40 consecutive patients with chronic suppurative otitis media with cholesteatoma was included in this study. Both high-resolution computed tomography of the petrous bone and non-echoplanar diffusion-weighted magnetic resonance imaging were performed. This was followed by their fusion. Patients were classified according to The European Academy of Otology and Neurotology, in cooperation with the Japanese Otological Society Joint Consensus Statement on the Definitions, Classification, and Staging of Middle Ear Cholesteatoma. All patients were operated, and the technique was tailored according to the data obtained from the preoperative fusion of computed tomography and diffusion-weighted magnetic resonance imaging and the intraoperative findings.Results:Patients were equally divided between males and females with a mean age of 26.8 years of which 52.5% were left-sided ears. The fusion of high-resolution computed tomography and diffusion-weighted magnetic resonance imaging had a 100% sensitivity and 88.9% specificity regarding The European Academy of Otology and Neurotology, in cooperation with the Japanese Otological Society classification. On the other hand, it showed 100% specificity and 100% sensitivity for all middle ear subsites except sinus tympani which obtained 55.56% sensitivity and 100% specificity. In all patients with preoperative fusion showing cholesteatoma not reaching the mastoid antrum (30%), exclusive endoscopic approach was employed, and no postauricular incision was needed.Conclusion:The fusion of high-resolution computed tomography and diffusion-weighted magnetic resonance imaging images is an accurate tool for localizing cholesteatoma in various middle ear cleft subsites. This makes it a valuable tool for cholesteatoma classification and staging and surgical planning preoperatively.

The characterization of ancient DNA in fossil bones is providing invaluable information on the genetics of past human and other animal populations. These studies have been aided enormously by the discovery that ancient DNA is relatively well preserved in the petrous bone compared to most other bones. The reasons for this better preservation are however not well understood. Here we examine the hypothesis that one reason for better DNA preservation in the petrous bone is that fresh petrous bone contains more DNA than other bones. We therefore determined the concentrations of osteocyte cells occluded inside lacunae within the petrous bone and compared these concentrations to other bones from the domestic pig using high resolution microCT. We show that the concentrations of osteocyte lacunae in the inner layer of the pig petrous bone adjacent to the otic chamber are about three times higher (around 95,000 lacunae per mm3) than in the mastoid of the temporal bone (around 28,000 lacunae per mm3), as well as the cortical bone of the femur (around 27,000 lacunae per mm3). The sizes and shapes of the lacuna in the inner layer of the petrous bone are similar to those in the femur. We also show that the pig petrous bone lacunae do contain osteocytes using a histological stain for DNA. We therefore confirm and significantly expand upon previous observations of osteocytic lacuna concentrations in the petrous bone, supporting the notion that one possible reason for better preservation of ancient DNA in the petrous bone is that this bone initially contains at least three times more DNA than other bones. Thus during diagenesis more DNA is likely to be preserved in the petrous bone compared to other bones.

A 30-year-old female patient was diagnosed with right medial sphenoid wing meningioma when she was evaluated for her headache and dizziness. She underwent craniotomy and excision and, biopsy showed grade 1 microcystic meningioma with an MIB-1 labeling index of 1 to 2%. Her follow-up magnetic resonance imaging (MRI) at 2 years showed recurrence of the lesion and she was referred to our hospital for gamma knife radiosurgery (GKRS). On examination, she had 30 to 40% sensory loss along the distribution of the right trigeminal nerve. She had a 1.3 × 1.7 cm intensely enhancing globular extra-axial lesion along the right temporal convexity with extension to Meckel's cave and abutting the right trigeminal nerve ([Fig. 1]). She underwent secondary GKRS with a dose of 12 Gray. She subsequently noticed a globular mass protruding out from her external auditory canal with associated purulent foul-smelling discharge and had conductive hearing loss ([Fig. 1]). Computed tomography (CT) and Contrast enhanced magnetic resonance imaging (CEMRI) scan of the temporal bone showed a lobulated extra axial mass causing erosion of the petrous bone and tegmen tympani with extension to the middle ear, mastoid antrum, and external auditory canal. Intracranial meningiomas extending into the middle ear and subsequently into the external auditory canal are extremely rare. Kusunoki et al noted a case of recurrent sphenoid wing meningioma extending into the middle ear in a 74-year-old female patient.[1] Reitz et al suggested that intracranial meningiomas can enter the middle ear through various routes such as petrous pyramid, tegmen tympani, internal auditory canal, jugular fossa, and canal for greater superficial petrosal nerve. In our case, the likely path of spread would be the tegmen and petrous pyramid.[2] She underwent preauricular subtemporal transzygomatic approach and near total excision of the lesion by the ENT department and biopsy proved to be meningioma again.

Background: Petrous temporal bone (PTB) fractures result from high energy head trauma and are associated with specific neurological and otological complications, as well as substantial intracranial injuries. Timely and appropriate management is required to ensure optimal outcomes. This study aims to describe the incidence and complications of PTB fractures in an Australian adult population and produce an evidence-based clinical practice guideline for their management.

The neurotologic literature commonly describes venous sinus thrombosis as a complication of mastoiditis. However, thrombosis of the internal carotid artery in the setting of mastoiditis is rarely described. We aim to document a case of carotid artery thrombosis in a patient presenting with mastoiditis. We describe this case and review relevant literature. A renal transplant patient was transferred to our hospital with a left middle cerebral artery (MCA) infarct due to acute mastoiditis. Examination demonstrated middle ear effusion and radiologic workup confirmed mastoid infection adjacent to the site of arterial thrombosis. During cortical mastoidectomy and facial recess approach to the middle ear, the petrous carotid bone was found to be dehiscent with pneumatization of the petrous apex. Thrombosis was found to resolve following surgery, IV antibiotics and anticoagulation. Clinically, his focal neurological deficits improved. Proximity of the infectious process to an exposed petrous carotid artery supports the hypothesis that this patient's thrombus was a product of infectious spread and extra-luminal compression. To our knowledge, this is the first report of MCA infarction due to petrous ICA arterial thrombus in the setting of mastoid infection. The patient's immunocompromised state may have predisposed and contributed to the adverse outcome. We advocate for aggressive management of acute mastoiditis in the immunocompromised to prevent or manage complications (such as venous thrombophlebitis as well as ICA thrombus) as these patients don't show typical signs of infection and inflammation.

Abstract Background first case of a rare Garcin syndrome resolution in a young metastatic breast cancer(BC) patient treated with a hippocampal-sparing approach. Material and Methods we report a case of a 49-year-old caucasian female. The medical record review was relevant for BC diagnoses in 1997, when she was 26yo; complicated by bone and liver metastasis appeared in 2008. In March 2020, she was referred to our department complaining about increasingly worsening left otalgia with initial hearing loss, left facial numbness, and homolateral decreased facial sensitivity, left increased lacrimation, and tingling tongue. Clinical presentation was suggestive for a Guillain-Alajouanine-Garcin Syndrome (Garcin Syndrome), caused by a lytic lesion in the left sphenoid wing. A contrast MRI (02/04/2020) of the brain demonstrated a lytic lesions in the left sphenoid wing, that was noted to infiltrate surrounding bone of the sphenoid sinus wall, including clivus, left pterygoid process and petrous bone; two parietal and occipital bone lesions were identified with a partial leptomeningeal involvement. According to the good PS, she underwent to a hippocampal-sparing WBRT VMAT plus a sequential boost on sphenoid lesion. PTV and OARs were delineated according to a fused planning MRI/CT image. Bilateral hippocampal contours were generated on the set according to RTOG 0933 contouring atlas. After that, a hippocampal avoidance(HA) region was created by expanding the hippocampal contours by 5 mm in all directions according to Brown et al.The PTV-HA was defined as the WB parenchyma, meninges and skull, excluding the HA-region, dose prescription 30Gy/10fx; the PTV-Boost was defined as the sphenoidal metastases, dose prescription of sequential boost was 12Gy/4fx. VMAT was used to deliver the conformal RT plan. Planning priorities that should be followed were:Hippocampus, OpticChiasm, OpticNerve_L or OpticNerve_R, Lens_L or Lens_R. Results The neurological symptoms improved after the end of RT with a complete resolution two months later. At the last MRI, a year and a half from the end of RT, there was no evidence of brain lesion, and no neurological symptoms were referred. These are our results of plan sum: for PTV-HA D2%=43.43 Gy, D98%=26.36 Gy, V30=94.96%; for Hippocampus D100%=8.78 Gy, Dmax=17.24 Gy; for Left OpticNerve Dmax=33.51%; for Right OpticNerve Dmax=29.25%; for OpticChiasm Dmax=35.93%. Conclusion To our knowledge, this is the first described case using the VMAT technique to spare the hippocampus plus a boost in a rare case of Garcin Syndrome. Prevention of neurocognitive sequelae by hippocampal avoidance has shown promise in several studies as in this case. Sequential boost demonstrated to be feasible and effective.Advanced RT techniques may be used to customize a treatment that allows preserving cognitive impairment achieving good clinical results in the long-term survival of metastatic patients.

Studies evaluating DNA preservation in non-adults, or comparing preservation in adults and non-adults, are very rare. This study compares the preservation of DNA in the skeletal remains of adults and non-adults. It compares the quality and quantity of DNA recovered from different skeletal elements of adults and non-adults, and from non-adults of different age classes. In addition, the preservation of DNA in males and females is compared. Bone DNA preservation was estimated by measuring nuclear DNA concentration and its degradation, and through STR typing success. The study analyzed 29 adult skeletons and 23 non-adult skeletons from the Ljubljana-Polje archeological site, dating from the seventeenth to nineteenth century, and up to four skeletal elements (petrous bone, femur, calcaneus, and talus) were included. After full demineralization extraction, the PowerQuant System and the PowerPlex ESI 17 Fast System (Promega) were used for qPCR and STR typing, respectively. The results showed that, among the four bone types analyzed, only the petrous bone proved to be a suitable source of DNA for STR typing of non-adult skeletal remains, and DNA yield is even higher than in the adult petrous bone, which can be attributed to the higher DNA degradation observed in the adult petrous bone. In adult skeletons, petrous bones and tali produced high STR amplification success and low DNA yield was observed in adult femurs. The results of this study are applicable for the sampling strategy in routine forensic genetics cases for solving identification cases, including badly preserved non-adult and also adult skeletons.

To test the usefulness of the forensic PCR-MPS approach to eye and hair color prediction for aged skeletons, a customized version of the PCR-MPS HIrisPlex panel was used on two sets of samples. The first set contained 11 skeletons dated from the 3rd to the 18th centuries AD, and for each of them at least four bone types were analyzed (for a total of 47 samples). In the second set, 24 skeletons from the Second World War were analyzed, and only petrous bones from the skulls were tested. Good-quality libraries were achieved in 83.3% of the cases for the ancient skeletons and in all Second World War petrous bones, with 94.7% and 100% of the markers, respectively, suitable for SNP typing. Consensus typing was achieved for about 91.7% of the markers in 10 out of 11 ancient skeletons, and the HIrisPlex-S webtool was then used to generate phenotypic predictions. Full predictions were achieved for 3 (27.3%) ancient skeletons and 12 (50%) Second World War petrous bones. In the remaining cases, different levels of AUC (area under the receiver operating curve) loss were computed because of no available data (NA) for 8.3% of markers in ancient skeletons and 4.2% of markers in Second World War petrous bones. Although the PCR-based approach has been replaced with new techniques in ancient DNA studies, the results show that customized forensic technologies can be successfully applied to aged bone remains, highlighting the role of the template in the success of PCR-MPS analysis. However, because several typical errors of ancient DNA sequencing were scored, replicate tests and accurate evaluation by an expert remain indispensable tools.

IgG4-related disease (IgG4-RD) involving the temporal bone is an uncommon and underrecognized pathology often mistaken for malignancy. This systematic review is the first that aims to thoroughly analyze IgG4-RD of the temporal bone. Ovid MEDLINE, EMBASE, Cochrane Library, and Google Scholar. We used the following search keywords: "lgG4-RD," "skull," "skull base," "cranial," "temporal bone," "inner ear." We additionally manually searched the bibliographies of relevant articles. The JBI Critical Appraisal Checklist for Case Reports and Case Series was used to assess the risk of bias; because of the scarcity of the reports, data were available through limited case series and reports; thus, data synthesis was not possible. We identified 17 studies with 22 cases with temporal bone involvement. The most common presenting symptoms were hearing loss, otalgia, and headache. The mastoid and petrous bone were the most affected anatomical areas. Both computed tomography and magnetic resonance imaging were used. Biopsies showed the characteristic lymphoplasmacytic infiltrate in all cases, with histopathology being the diagnostic modality that set the diagnosis. Most patients were treated with corticosteroids ± surgery or a combination of corticosteroids and immunosuppressants with 95.5% symptomatic response and disease control. IgG4-RD of the temporal bone radiologically manifests as space-occupying, lytic lesions; clinically, it presents with vague otological symptoms. Diagnosis involves a thorough workup, with histopathology being crucial in setting a definite diagnosis. IgG4-RD tends to respond well to systemic corticosteroids, whereas surgery is mostly required for diagnostic purposes.

BackgroundPrimary tuberculous otitis media is rare in the paediatric age group, and its neuro-otogenic complication of involvement of cerebellopontine angle in a child is very unusual. Tuberculosis should always be considered as a rare but possible aetiology for such neuro-otogenic lesions.Case presentationWe report a case of a 13-year-old female patient who presented with left ear discharge and mass-like lesion on otoscopy. High-resolution computed tomography (HRCT) temporal bone showed erosion of petrous temporal bone, external auditory canal and ossicles. Contrast-enhanced MRI (CEMRI) revealed peripherally enhancing hetero-intense lesion epicentred in the petrous and mastoid part of left temporal bone extending into the left cerebellopontine angle and external auditory canal. Homogenously enhancing soft tissue was seen in the left occipital condyle with sigmoid sinus thrombosis and cervical lymphadenopathy. There was also a single enhancing left temporal lobe lesion. Radiological and clinical assessment was suggestive of malignant aetiology. However, biopsy revealed tuberculosis and anti-tubercular therapy (ATT) was initiated. Interval imaging showed an adequate response to treatment.ConclusionsTuberculous otitis media often masquerades as malignancy on clinical and imaging assessment.

Abstract This study compares histological preservation in archeological bones from different burial types to unravel the histotaphonomy‐to‐funerary practices relationship. Αn intraskeletal approach is also adopted to explore intraindividual (inner ear part of the petrous bone vs. upper/lower limb long bones) and intrabone (proximal vs. distal diaphysis) variability in bone collagen preservation, δ13C, and δ15N. The aim is to (a) target bones that likely retain higher amounts of collagen, (b) better understand the inner ear bone collagen isotopic signature and remodeling, and (c) assess intrabone isotopic and histological homogeneity. For the histological analysis, the data have been collected from 61 specimens (20 individuals) from the medieval/postmedieval cemetery of St. Rombout, Belgium. Thin sections have been studied using optical and scanning electron microscopy. For the collagen and isotopic data, 101 samples have been collected from 21 individuals. Distinct histological patterns are observed only in bones from single coffin burials; however, bone histology can display intraindividual and intrabone variability, which are important to account for interpretations. Collagen wt.%, δ13C, and δ15N show significant intraindividual differences but insignificant intrabone variability. This study also confirms the extraordinary nature of the petrous bone, as the inner ear bone collagen δ13C and δ15N values reflect the dietary input of the first approximately 2–3 years of life.

Objectives and DesignEndolymphatic sac tumors (ELSTs) are rare and indolent tumors that arise from the endolymphatic sac in the posterior petrous ridge. We present a video case report illustrating the use of a transotic approach for resection of an expansile ELST.Setting and Participants A 25-year-old male presented with a multiyear history of worsening left-sided hearing loss, vertigo, and headaches. Otoscopy revealed a red mass behind an intact tympanic membrane. Computed tomography revealed a large, locally aggressive mass centered in the posterior petrous temporal bone. Magnetic resonance imaging demonstrated a heterogeneously enhancing 2.4 × 3.1 × 2.4 cm tumor that exerted mass effect on the cerebellar surface with extension into the jugular foramen, tympanic cavity, internal auditory canal, and cistern of the cerebellopontine angle. A transotic approach was planned to obtain the necessary generous exposure.Main Outcome Measures and Results Preoperative angiography revealed arterial supply via the ascending pharyngeal and tumor embolization with Onyx was performed. Surgical resection began with a blind-sac closure created from the external auditory canal. The tympanic membrane and malleus were removed and the incustapedial joint was transected. A subtotal petrosectomy was performed for partial tumor exposure. The facial canal and sigmoid sinus were carefully skeletonized and a labrynthectomy was performed. The tumor was resected using a combination of bipolar cautery and blunt and sharp dissection. For closure, an abdominal fat graft was secured with overlying resorbable mesh followed by sequential closure of all skin layers. Histopathologic analysis revealed an ELST.Conclusion The transotic approach offers wide exposure and facilitates large, complex tumor removal.The link to the video can be found athttps://youtu.be/YvhyN8iVi44.

側頭骨錐体部を介した髄液漏は，稀ではあるものの難治性の頭蓋内感染症を生じることが知られている．その原因には頭部外傷，錐体骨周辺の手術，腫瘍，放射線治療，中耳炎，先天性，特発性などが報告されているが，その原因の如何を問わず，繰り返す髄膜炎や致死的な重症頭蓋内感染症を生じうる．治療には髄液の漏出部位の正確な特定と速やかな閉鎖が推奨されるが，画像診断では同定困難なことが多い．そのため漏出する可能性がある部位を推測して同定することが重要である．本報告では経頭蓋的なアプローチによる欠損部の修復術により良好な経過をたどった治療経験をふまえ，効果的な修復術を達成するための工夫について述べる．