Petrous Bone Research Articles

In 1970, Luca Cavalli-Sforza and I began to work on the question of the Neolithic transition in Europe. We started by measuring the rate of spread of first farming over the continent as a whole and in three of its regions. In turn, we went on to put forward the wave of advance model as a new way to explain the shift from hunting and gathering in a mobile way of life to the production of food in the context of sedentism. The aim here is to review our collaboration and what we wrote on the subject over a span of 50 years. The work will be developed in six main sections: (1) the initial studies, (2) the synthesis in 1984, (3) the widening harvest, (4) the analysis of ancient DNA in the bones of first farmers, (5) the discovery of the petrous bone and (6) Discussion.

In most cases, inflammatory diseases of the petrous bone can be diagnosed clinically. However, for certain diseases, the extent of the findings must be assessed using cross-sectional imaging, or important complications such as cerebral complications must be excluded. The petrous bone is part of the temporal bone, consisting of the pars squamosa, pars tympanica, and pars mastoidea [1]. It encompasses the inner ear, the internal auditory canal, and the petrous bone itself. Anatomically, the middle ear and mastoid already belong to the pars tympanica and pars mastoidea [1]. Imaging should ideally be carried out in conjunction with adetailed medical history, especially information about previous surgeries, chronic infections, possible anti-inflammatory medications, and the current otoscopic findings. The description should always be systematic, e.g., from outside to inside. Within the anatomical structures, different inflammatory processes can occur. Infections are one of the main causes of inflammation in the temporal bone. Important differential diagnoses must be considered. This article discusses the most important inflammatory lesions of the temporal bone and middle ear and the differential diagnoses.

ObjectivesChronic Nonbacterial Osteomyelitis (CNO) is an autoinflammatory disorder of bone typically beginning children between the ages of 7-12. Any bone can be affected, involvement of the skull is unusual and petrous bone involvement has not been reported. The objective of our study is to illustrate presenting features associated with CNO of the petrous temporal bone, its treatment, and response to therapy. The second is to increase awareness that CNO can involve the petrous temporal bone with the hope it will aid in diagnostic clarity for challenging cases.MethodsCases of patients diagnosed with CNO between June 2002-May 2022 at The Hospital for Sick Children were identified by searching Bialogics and the Electronic Medical Record Epic. Charts were searched for the term “skull” to identify cases affecting the skull. To obtain records prior to 2018 we ran a word search of pertinent synonyms to identify cases of CNO involving the temporal bone in the ISYS imagining system. Research Ethics Board approval was obtained.ResultsThree cases of CNO affecting the petrous temporal bone, were identified (Figure 1). All had known CNO peripheral lesions. They ranged in age from 2-10 years old and were female. Two patients had 7th cranial nerve involvement and hearing loss. All patients were treated with a non-steroidal anti-inflammatory drug (NSAID) and 2 patients with hearing loss received anti-TNF therapy (adalimumab) and responded well with resolution of hearing loss in 1 case and residual mild to moderate conductive hearing loss in another. These cases are unique as they involve the skull, a less affected CNO site.[1,2] It typically affects metaphysis and epiphyses of the long bones, vertebral bodies, and the clavicle. Axial skeletal involvement is less prevalent (61%) compared to appendicular skeleton involvement (75%).[2] With 1% of patients presenting with skull lesions.[1,2] It is unknown why CNO rarely affects the skull. Theories include CNO tends to affect the metaphysis and epiphyses of the long bones which the skull does not have. Another is there is increased metabolic activity at the epiphysis with chondrocyte maturation which could result in increased propensity of immune dysregulation and inflammatory lesions.[3]ConclusionCNO typically affects the metaphysis of the long bone but can affect any bone in the body, including the temporal petrous bone of the skull. It is important to consider CNO on the differential in patients who present with cranial nerve abnormalities, facial nerve palsy, hearing loss, and those with presumed infectious osteomyelitis. [1.] Ferrara G. Clin Exp Rheumatol 2020;38(2):366-9. [2.] Borzutzky A. Pediatrics 2012;130(5):e1190-7. [3.] Shapiro IM. 2007;40(3):561-7.Best Abstract on Pediatric Research by Early Career Faculty Award

Objectives High-riding jugular bulb (HRJB) is an anatomical variation in the petrous temporal bone (PTB) that can be defined as the presence of the jugular bulb at the level of the basal turn of the cochlea in the axial plane. The presence of HRJB can increase the risk of injury during middle ear surgery and may contribute to the pathogenesis of conductive and sensorineural hearing loss. This study investigated the accuracy of a deep learning convolutional neural network (CNN) algorithm in identifying HRJB on axial PTB computed tomography (CT) scans. Methods Petrous bone CT scans were retrospectively obtained from consecutive patients imaged in January 2024 from an Australian tertiary hospital. Two blinded investigators – a board-certified otolaryngologist and an otolaryngology resident – labelled the images as either HRJB or normal. Training and test sets were created in a 2:1 ratio. Microsoft Azure's Custom Vision platform was utilised to devise the deep learning algorithm. Results 2400 images were collected from left, right and flipped axial PTB CT scans of 600 patients. After exclusions, 2367 final images were used. The CNN achieved an overall accuracy of 0.948 (95% CI 0.930–0.962), with a sensitivity of 92.9% and specificity of 95.5% for HRJB identification. Conclusion The CNN successfully identified HRJB on axial PTB CT scan images with a high degree of accuracy. This approach's robustness is premised on accurate labelling of datasets and rigorous cross-validation with a dedicated testing set. Future studies could explore CNNs for detecting other anatomical variations, potentially enhancing diagnostic accuracy and improving patient outcomes in Otolaryngology.

Denisovan mitochondrial DNA from dental calculus of the >146,000-year-old Harbin cranium.

The temporal bone is one of the most complex bones in the human body. Fractures require significant force and are usually associated with extensive damage to adjacent structures. Which imaging modality facilitates the assessment of petrous bone fractures, and which anatomical landmarks may be used for orientation? Aliterature search on PubMed.gov was conducted to determine the current state of research. Injuries to the petrous part of the temporal bone often involve the facial nerve and the vestibulocochlear nerve, as well as the cochlea and the vestibular organ. This article presents strategies to facilitate correct diagnosis. In addition to the (often knotty) description of the fracture, it is essential to assess the cranial nerves that transverse the petrous bone and to evaluate the auditory ossicles.

The posterior petrosal approach is a technically challenging procedure used to treat complex, deep-seated lesions. The petrosal ridge, located between the middle and posterior fossae, can be anatomically compared with the sphenoid ridge, which separates the anterior and middle fossae. Analogous to the orbitotemporal periosteal fold, which connects the orbit to the middle fossa dura, the endolymphatic sac (ELS) acts as a fold connecting the vestibule to the posterior fossa dura. This fold presents an obstacle to further elevating the dura from the posterior surface of the petrous bone. The objective of this study is to provide anatomic details and key landmarks for the preservation and safe peeling of the ELS, thereby expanding the surgical field during posterior petrosectomy and combined petrosal approaches. Five formalin-fixed cadaveric heads were injected with colored silicone, and 10 sides were used for cadaveric dissections. At the level of the superomedial margin of the operculum, the periosteal layer is incised to enter a surgical plane between the dura propria and the ELS. The dura is then peeled away from the posterior aspect of the ELS, and the periosteal layer is further incised along the ELS. A dural thickening continuing medially from the operculum, corresponding to the Tubingen line, allows access to the plane between the dural leaflets before reaching the full extent of the ELS. Analogous to the orbitotemporal periosteal fold in anterior approaches, the ELS can be safely peeled from the dura of the posterior fossa, thereby enhancing the extradural exposure in these approaches.

A case of a 10-year-old girl with rare association of temporomandibular joint anomaly with external and middle ear anomalies. It emphasizes on the importance of evaluating temporomandibular joint, mandibular condyle, temporal & petrous bone on HRCT in cases of external or middle ear anomalies for categorization, effective management, and reducing the overall childhood disability burden.

This study investigates the inverse use of the Vibrant Soundbridge® Floating Mass Transducer (FMT; MED-EL, Innsbruck, Austria) as amicrophone in apilot test. Should this be applicable, it would open up interesting application possibilities, e.g., as amicrophone for afully implantable cochlear implant. Experimental measurements on an ear canal-eardrum model were used to analyze the acoustic properties of the FMT when used as amicrophone, including frequency response and sensitivity. The FMT from the Direct Drive Simulation Set was coupled to the artificial eardrum for this purpose. The results show that the FMT has ausable signal-to-noise performance over the entire frequency range investigated, albeit with anon-linear frequency characteristic. The highest sensitivity was found between 1500 and 2000 Hz. The study suggests that an FMT optimized for microphone properties could be used as amicrophone in the middle ear, which would open up new possibilities for the development of fully implantable hearing systems. Further investigations, in particular measurements on the petrous bone, are required to determine the suitability of the FMT as amiddle ear microphone more precisely.

Tumors of the petrous bone pose asignificant challenge in radiological diagnostics due to their complex anatomical location. This article provides an overview of the imaging characteristics of the most important tumors and tumor-like lesions of the petrous bone.

Effects of different environmental factors on preservation of DNA in petrous bones: A comparative study of two Slovenian archaeological sites.

Ear tumors: Surgical aspects

The anatomy of the petrous bone is very complex, particularly due to the many important nervous, vascular and muscular structures that run through it, as well as the protection of hearing and balance organs. Anatomical standard variants complicate radiological interpretation, can imitate pathologies, and present surgeons with enormous challenges during surgical procedures. Morphological imaging-based diagnostics for detecting normal anatomical variants of the petrous bone include computed tomography (CT) and/or magnetic resonance imaging (MRI). The patient's precise history of existing symptoms or previous surgery also plays arole in the assessment of the findings. Radiologists must be aware that some anatomical standard variants can mimic pathology, and therefore there is arisk of misinterpretation. The imaging helps surgeons facilitating preoperative planning and identification of possible complications. Precise radiological knowledge of the complex anatomical relationships of the petrous bone is crucial in routine radiological and neuroradiological practice. Adetailed description of existing anatomical standard variants enables colleagues in surgical disciplines such as otolaryngology and neurosurgery to efficiently prepare the procedures and assess possible complications.

The lateral angle of the internal acoustic meatus of the petrous bone is a sexually dimorphic feature used for sex determination, particularly in fragmented or cremated remains. However, studies show conflicting results regarding its accuracy, and the reasons for its dimorphism remain unclear. The aim of this study is to analyze sexual dimorphism in subadult individuals and to examine the association of the lateral angle with cranial breadth as an explanation for its sexual dimorphism, as well as interpopulation differences. We measured the lateral angle and biauricular breadth in 204 individuals (birth to 30 years) using CT scans from Austrian 19th-century anatomical collections and data from the New Mexico Decedent Image Database. This study revealed that the sexual dimorphism of the lateral angle and cranial dimensions manifests during puberty, along with a strong association between the lateral angle and the biauricular breadth. Additionally, this study noted interpopulation variability in cranial breadth, with different levels of sexual dimorphism observed across diverse populations. The findings offer a potential explanation for the observed variability in lateral angle measurements across studies and the limitations of universal cut-off points as a sex-determination method in osteology.

BackgroundActive Facial nerve (FN) management, including decompression, end-to-end or rerouting anastomosis, and grafting consistently plays an important role in the surgical management of petrous bone cholesteatoma (PBC), and postoperative FN function is also a major concern for surgeons. The aim of this study is to analyze the long-term FN function outcomes in PBC patients with FN paralysis who have underwent different managements and to explore the prognostic factors.MethodsA retrospective analysis of 160 PBC patients with preoperative FN paralysis was conducted, and long-term FN function outcome was evaluated. Multivariate ordinal logistic regression models were used to determine the prognostic factors.Results160 patients were collected. 102 males (63.75%) and 58 females (36.25%) with mean age 34.09 ± 13.54 years (range: 5.58-77 years). Mean FN paralysis duration preoperatively was 62.5 ± 90.80 months (range: 4 days-46 years). The preoperative/postoperative House-Brackmann (H-B) grade are as follows: H-B (I-II): 0/38 cases, H-B III: 11/37 cases, H-B IV: 22/38 cases, H-B V: 21/14 cases. H-B VI: 106/33 cases. The poorer preoperative FN function, the poorer postoperative FN function (rs=0.745, P < 0.001). Among 160 PBC patients, 127 patients underwent active FN management, 94/127 (74.0%) with preoperative H-B (V-VI) improved postoperatively. 33 patients were not eligible for FN repair, due to prolonged period of complete FN paralysis. FN decompression achieved H-B (I-II) recovery in 100% of H-B (III-IV) patients (22/22) within 12 months of paralysis and 88.9% (8/9) of H-B (V-VI) patients operated within 2 months of paralysis. End-to-end/rerouting anastomosis achieved H-B III recovery in 77.8% (14/18) of patients treated within 12 months. Greater auricular nerve graft within 12 months of paralysis achieved H-B III recovery in 75% of patients. Hypoglossal-FN anastomosis yielded H-B IV recovery in 7/12 patients (58.3%). Multivariate analysis identified worse preoperative FN function and prolonged FN paralysis duration (P < 0.05) as independent risk factors for poor prognosis.ConclusionsPatients with FN paralysis can undergo active FN management to reconstruct FN function, depending on the preoperative FN function and the duration of FN paralysis. Worse preoperative FN function and longer duration of FN paralysis (P < 0.05) are risk factors for poorer prognosis.

Background:This study aimed to see the change in the area covered by the inner ear (IE) in the petrous bone with gestational age, and to determine the growth dynamics of inner ear structures such as the cochlea and semicircular canals.Methods:Twenty temporal bones of 10 fetal cadavers (5 males and 5 females) aged 23.50 ± 2.94 weeks were included in the study.Results:The petrous ridge length (PRL), the inner ear length (IEL), the thickness of bone on the cochlea, the distance of the rearmost part of the superior semicircular canal to the most posterior border of the petrous ridge, and the distance of the frontmost part of the cochlea to the most anterior border of the petrous ridge were measured as 23.97 ± 4.21 mm, 13.31 ± 1.45 mm, 1.26 ± 0.20 mm, 6.86 ± 1.97 mm, and 3.85 ± 0.93 mm, respectively. The ratio of the IEL to the PRL decreased despite of proportional increase in these parameters with age. This finding shows that the growth dynamics of the IE are slower than that of petrous bone, and thus the area ratio covered by the inner ear in the petrous bone decreased with age. The size of the cochlea and the angles between the semicircular canals did not correlate with gestational age. However, the semicircular canals (their thicknesses and inner surface areas) attain adult size between 21 and 24 weeks.Conclusion:Our findings may be useful for otologists to see the relation of the IE with the petrous bone. Our numeric dataset may form a basis of prenatal radiologic investigations.

A 3D radiological planning software for general otology has been developed to assist preoperative planning by providing anatomical measurements based on CT or MRI scans in cochlear implant candidates. This study aimed to investigate its usability for predicting the required posterior tympanotomy (PT) opening length to ensure visualization of the round window (RW). CT scans were performed on 30 petrous bone specimens. Correlations were analyzed between software-calculated distances of the ideal trajectory to critical inner ear structures and the intraoperatively measured required PT length to ensure visualization of the RW. This was assessed using the posterior tympanotomy window (PTW), which was defined as the distance between the most prominent curvature of the short process of the incus and the round window. We also analyzed the degree of facial nerve exposure and the feasibility of electrode array insertion. The mean PTW length was 7.31 mm (range, 5-9 mm). The intraoperative PTW significantly positively correlated with the distance between the chorda tympani and the ideal trajectory calculated by the software. The intraoperative PTW significantly positively correlated with the software-calculated facial recess size. A caudal extension of the PTW correlated with short distances between the facial nerve and the ideal trajectory. Facial nerve exposure negatively correlated with the software-calculated distance between the facial nerve and the ideal trajectory. Electrode insertion was possible in all study specimens. The software was useful in the preoperative planning of CI surgery. It may help to anticipate the RW visualization through the chorda-facial angle.

In cochlear implantation (CI), precise preoperative cochlear duct length (CDL) and angular insertion depth (AID) measurements are pivotal for individualized electrode carrier selection, since recipients benefit from sufficient cochlear coverage of the electrode carrier, enabling electric stimulation of all crucial frequency bands. Since the quality of temporal bone CT largely depends on acquisition and reconstruction settings and is limited by the technical capabilities of the CT scanner, this study aims to assess how radiation dose and reconstruction field-of-view (FOV) affect automatic cochlear morphometry and electrode contact determination in conventional multislice CT. Twenty fresh-frozen human petrous bone specimens were examined at three radiation dose levels (40, 20, and 10 mGy) using a multislice CT scanner. Each dataset was reconstructed with three different FOV settings (250, 125, and 50 mm). Preoperative CDL and AID measurements were performed with dedicated otological planning software. Maxed-out dose images (250 mGy) served as standard of reference for comparing the morphometric results. Regardless of the selected combination of dose level and FOV, significant CDL or AID measurement differences were neither ascertained among the individual groups, nor in comparison to the reference scans (all p ≥ 0.05). Likewise, the simulation of all stimulable frequency bandwidths showed no dependency on radiation dose or FOV settings (all p ≥ 0.05). The assessment of cochlear morphometry with conventional multislice CT imaging before CI surgery allowed a radiation dose reduction up to 75% without compromising the accuracy of software-based cochlear analysis. Notably, automatic CDL and AID measurements for surgical planning did not benefit from a smaller reconstruction FOV.

Otorrhea can result from middle ear discharge with tympanic membrane perforation, external ear canal pathology, skull injury and other serious diseases in trauma and immunocompromised patients.1 Thorough investigation is warranted in cases without improvement after treatment. We present a case where fibrous dysplasia was the underlying cause and discuss its treatment. CASE REPORTA 41-year-old farmer man consulted at our ENT Outpatient Clinic with a 1-year history of clear, non-foul-smelling discharge from his left ear, associated with intermittent pounding ear pain. A hard immobile nontender prominence was noted over the patient’s left temporal area. (Figure 1) He was initially treated for chronic suppurative otitis media for 3 months. Severe ear pain was noted, 10/10 on pain scale, squeezing in character, radiating to the left temporal and parietal area associated with progressive hearing loss and ear fullness. Plain CT scans revealed a combined lytic and ground glass expansile lesion involving the left occipital, mastoid, and petrous temporal bone and portion of the parietal bone obliterating the external auditory canal and middle ear. (Figure 2) On physical examination, a hard immobile nontender prominence was noted over the patient’s left temporo-parietal area. No facial asymmetry or numbness was noted. On otoscopy, there was a skin-colored round smooth hard immobile nontender mass in the external auditory canal with non-foul smelling whitish to yellowish purulent discharge. A Weber tuning fork test lateralized to the left and a Rinne test revealed air conduction &lt; bone conduction on the left, and air conduction &gt; bone conduction on the right. The patient was admitted with an impression of chronic suppurative otitis media, left; to consider fibrous dysplasia vs. tuberculosis. Aerobic culture of ear discharge revealed no growth. Canal down mastoidectomy was done. Intraoperative findings revealed granulomatous and cartilaginous lesions on the mastoid and temporal bone. (Figure 3) There were aural polyps and cholesteatoma with the ossicles apparently eroded by the lesion. (Figure 4) Temporal bone fluid was sent for GeneXpert MTB/RIF while the surgical specimen was sent for histopathology. GeneXpert MTB/RIF revealed negative results for tuberculosis. Final histopathology results showed fibrous dysplasia.

The authors aim to report a rare case of supratentorial temporobasal hemorrhage occurring after resection of a cerebellopontine angle (CPA) meningioma through a retrosigmoid approach and to elucidate the underlying mechanisms of this postoperative complication while offering surgical insights to prevent its occurrence. In the present study, the authors report a case of a 52-year-old female patient admitted for "dizziness for 1 year, exacerbated over the past 3 months". Preoperative magnetic resonance imaging (MRI) revealed a 2.5 cm×2 cm ×2CPA meningioma, classified as Simpson grade I, attached to the right petrous bone and tentorium cerebelli. The patient underwent gross total resection (GTR) through a retrosigmoid approach. Intraoperatively, tumor invasion into the tentorium was found, with slow oozing from the tentorial layer during resection, controlled by repeated electrocoagulation. Three hours postoperatively, the patient's consciousness deteriorated. Emergency computed tomography (CT) revealed a massive supratentorial temporobasal hemorrhage, prompting urgent hematoma evacuation. The patient fully recovered without neurological sequelae after hematoma evacuation. The authors propose that excessive electrocoagulation during resection may have impaired temporobasal venous drainage, leading to hemorrhage. This case illustrates a novel mechanism underlying surgical hemorrhagic complications and underscores the importance of hemostasis techniques during resection of the tumor within the tentorial layer, as well as the protection of temporobasal venous drainage.