Petrous Bone Research Articles

Neurodevelopmental disorders are thought to arise from intrinsic brain abnormalities. Alternatively, they may arise from disrupted crosstalk among tissues. Here we show the local reduction of two vestibulo-cerebellar lobules, the paraflocculus and flocculus, in mouse models and humans with 22q11.2 deletion syndrome (22q11DS). In mice, this paraflocculus/flocculus dysplasia is associated with haploinsufficiency of the Tbx1 gene. Tbx1 haploinsufficiency also leads to impaired cerebellar synaptic plasticity and motor learning. However, neural cell compositions and neurogenesis are not altered in the dysplastic paraflocculus/flocculus. Interestingly, 22q11DS and Tbx1+/– mice have malformations of the subarcuate fossa, a part of the petrous temporal bone, which encapsulates the paraflocculus/flocculus. Single-nuclei RNA sequencing reveals that Tbx1 haploinsufficiency leads to precocious differentiation of chondrocytes to osteoblasts in the petrous temporal bone autonomous to paraflocculus/flocculus cell populations. These findings suggest a previously unrecognized pathogenic structure/function relation in 22q11DS in which local skeletal deformity and cerebellar dysplasia result in behavioral deficiencies.

Skeletonized human remains from Second World War mass graves in Slovenia are a major challenge in genetic identification, and bones with a high DNA yield must be selected for successful identification. The goal of this study was to construct skeletal sampling strategy recommendations through comparison of the most appropriate groups of skeletal elements. Altogether, 566 bones and teeth from the same mass grave were compared, half analyzed in this study and half in previous studies performed by our group. After anthropological examination, mechanical and chemical cleaning was performed, followed by bone and tooth powdering. Total demineralization of 0.5 g of bone and tooth was followed by extraction and purification of DNA with a Biorobot EZ1 device (Qiagen). The qPCR PowerQuant kit (Promega) was used to measure the amount of DNA, and statistical analysis was performed. Skeletal elements were selected according to known better preservation of DNA in the human body, and they were arranged in seven groups: petrous bone, long bones (femur and tibia), torso bones (first rib and 12th vertebra), metacarpals, metatarsals, short and sesamoid bones (talus, navicular, medial cuneiform, cuboid, calcaneus, and patella), and teeth. Sampling strategy recommendations were constructed based on DNA quantity and quality results. The petrous bone group, metacarpal group, torso bone group, and short and sesamoid bone group produced the highest DNA yields. Accordingly, in addition to standard sampling of long bones (femurs and tibias) and teeth, those additional bone types should be collected for Slovenian Second World War victim identification.

Fragments of two skulls of young cetotherium baleen whales have been described from the Fortep’yanka 2 locality (Russia, Republic of Adygea, Maikop district, Fortep’yanka river valley, Upper Miocene, Upper Sarmatian, Blinovskaya Formation). Based on the morphology of the posterior (mastoid) process of the petrous bone, the structure of the posterior edge of the temporal fenestra, and the S-shaped shape of the superoccipital ridges, the finds were attributed to Kurdalagonus maicopicus (Spasskii, 1951). The proportions of the skull and the degree of closure of the sutures of the skull made it possible to determine the individual age of these whales within a year. New findings significantly complement the data on the structure of the sutures of the lateral wall of the skull and age-related variability of cranial morphology in representatives of the genus Kurdalagonus.

Analysing genetic material from skeletonised human remains has become valuable in forensic and archaeological contexts. While the petrous bone is often preferred for DNA extraction, its availability is not guaranteed, and because of destructive sampling, it is not frequently used in forensic cases. This study explores the potential of patellae as an alternative source of bone material for genetic investigations. Forty-five patellae were sampled from a post-World War II mass grave and an archaeological Christian cemetery dated from the 13th to 19th centuries. A full demineralisation extraction method was used to obtain the DNA, and real-time PCR quantification was used to determine the quantity and quality of DNA. To evaluate the suitability of patellae for forensic and archaeological analyses, short tandem repeat (STR) typing was performed using the ESI17 Fast PCR amplification kit (Promega). To explore the difference in DNA yield, DNA degradation and STR typing success between the post-World War II and archaeological patellae, statistical analysis was performed. The results revealed significantly higher DNA yield and STR typing success in WWII patellae and higher degradation of DNA in archaeological patellae, highlighting the impact of environmental exposure time on genetic material preservation. Almost all WWII patellae achieved a high success rate in STR typing with full profiles generated. More than half of the archaeological patellae showed high STR typing performance and highly informative partial profiles were obtained, indicating the suitability of patellae not only for forensic purposes but also for archaeological genetic analyses.

INTRODUCTION. The posterior petrous bone meningiomas are one of the most difficult tumors for microsurgical removal. Despite the modern possibilities of neurosurgery, the mortality and disability rates of these patients continue to be high.AIM. To analyze results of microsurgery of posterior petrous bone meningiomas depending on the location of the tumor matrix.MATERIALS AND METHODS. The study assessed the results of microsurgical treatment of 59 patients with large and giant posterior petrous bone meningiomas. All patients underwent microsurgical removal of the tumor by retrosigmoid approach. The Karnofsky Performance Scale Index at admission and discharge, the radicality of surgery, the presence of complications, the severity of neurological disorders and the outcome on the Glazgo Outcome Scale Extended were assessed.RESULTS. In 30.5 % of patients, meningiomas had petroclival localization, in 10.2 % of cases the tumor matrix was located in the area of the jugular foramen, in 8.5 % of patients the matrix was expanded and occupied the entire surface of the petrous bone and in 50.8 % of cases the tumor arose in the area of the posterior surface of the petrous bone. In 76.3 % of cases, the tumor was removed radically, in 15.2 % – subtotally and in 8.5 % – partially. The median functional status at the time of discharge was the highest in the group of patients with meningiomas of the posterior face of the petrous bone (p=0.006). Ischemic complications were more common in patients with an extended matrix (p=0.002). The best results of facial nerve function were achieved in the group of patients with meningiomas of the posterior face of the petrous bone (p<0.001). The largest number of patients with postoperative prosoparesis was observed in the groups of jugular meningiomas (p=0.016) and meningiomas with an extended matrix (p=0.032).CONCLUSION. The results of surgical treatment depend on the size and the localization of the tumor matrix. The greatest radicality and the best functional outcomes can be achieved in the group of patients with meningiomas of the posterior face of the petrous bone. The most common postoperative neurological disorders and low functional status were observed in patients with an extended tumor matrix over the entire surface of the petrous bone.

The high-resolution computed tomography (HRCT) scan used in the 1980s offers a distinct advantage in interpreting images of the temporal bone. To obtain a right image reconstruction and to provide meaningful information, a certain degree of tilt is required so that radiologists and clinicians can get more real imaging information on structural abnormalities in the temporal bone and its soft tissue constituents. The technique or protocol in HRCT of the temporal bone becomes an essential primary aspect in presenting the analyzed structure, the assessment of the small form of the auditory bones, the soft tissue of the inner ear and the cranial nerves that pass through the temporal bone structure is much easier to analyze, of course with the help of reconstruction according to the HRCT protocol for temporal bone, however, soft tissue evaluation is preferable to MRI. In the end, the standard structure, congenital abnormalities and pathological problems in the temporal bone structure can be identified and informed to the clinician as a step to determine further treatment action.

The term petrous bone cholesteatoma (PBC) represents a slow-growing epidermal lesion arising from the petrous part of the temporal bone. It is a rare incidence accounting for only 4-9% of all petrous bone lesions. PBC represents a real surgical challenge due to its complex relationship with critical neurovascular structures. To demonstrate our experience in using various options of facial nerve (FN) management during surgical treatment of PBC and analyze the long-term facial function outcomes. Retrospective medical record review in a quaternary skull-base center. Medical records of 298 PBC cases operated between the years 1983 and 2024 were thoroughly evaluated. Sanna's classification scheme was used to classify cases into the appropriate class and the House-Brackmann (HB) grading system of the FN was used to assess the facial function pre- and postoperatively. A total of 298 PBC cases were surgically treated at our center. Males constitute 68% (n = 203) of total operated PBC patients while the rest 32% (95) were females, making the male-to-female ratio 2.2:1. The age in this series ranged from 9 to 85. According to updated Sanna's PBC classification, 44% were supralabyrinthine, 33% were massive, 9% were infralabyrinthine-apical, 8% were infralabyrinthine, and 5% were apical. On preoperative FN function examination, 45% (n = 133) of patients had various degrees of paresis and complete paralysis whereas 55% (n = 165) had normal FN function. The commonest degree of paresis observed was HB-III (18.5%) followed by HB-IV (5.7%). A total of 40(13.4%) patients, however, had complete facial paralysis at the initial presentation. The facial function was compromised more frequently in supralabyrinthine and massive PBCs. Among the total patients who had an abnormal facial function at presentation, 52% had paresis/paralysis for less than a year whereas 48% had FN paresis/paralysis for greater than one year. The most commonly used surgical approaches at our center were transotic (TO), modified transcochlear type A (MTCA) with rerouting of the FN, and translabyrinthine (TLAB) with external auditory canal (EAC) closure. Intraoperatively an intact fallopian canal was found only in 33% (n = 99) cases whereas the rest 67% (n = 199) had erosion of the fallopian canal either with intact (n = 24) or infiltrated FN (n = 175). The FN was maintained in the bony fallopian canal in 35% (n = 104) cases. An active form of FN management, however, was required in 65% (n = 194) of cases either intraoperatively or as a second-stage procedure. Factors affecting postoperative FN function include age, preoperative FN function (HB), duration of paralysis, class of PBC, surgical approach, and method of active FN management. PBCs represent diagnostically and surgically challenging lesions of temporal bone which are usually frustrating to the treating surgeon. Preoperative anatomic classification of the lesion enables the physician to choose the appropriate surgical approach. Sanna's classification is the most widely accepted system used to classify PBC. This classification is based on the relation of the lesion to the labyrinthine block. Active FN management, including rerouting, end-to-end anastomosis, cable nerve grafting, and masseteric-to-FN anastomosis routinely come into play in the surgical management of PBCs, and the postoperative FN results after such interventions can be satisfactory in most cases.

Semicircular canal dehiscence is a congenital syndrome that mainly affects the superior and, less commonly, the posterior semicircular canal in the temporal bone. This syndrome was first reported by Minor et al. in 1998. The prevalence is about 0.5% in the general population. The most characteristic symptom is the Tullio phenomenon, predominantly vertigo and nystagmus. Hearing loss (in particular conductive loss) often completes overall clinical picture. The dehiscence may be completely asymptomatic, in which case it is seen as an incidental finding on radiological investigations. Audiological evaluation includes audiometry and vestibular evoked myogenic potentials (VEMPs). Clinical symptoms are based on the pathophysiological concept of a third mobile window within the inner ear. Diagnosis is confirmed by high resolution petrous temporal bone CT with multiplanar reconstructions (MPRs) in the plane of the canal (Pöschls’ plane for the superior semicircular canal) and 3-D surface reconstructions. MR findings are less sensitive for this entity. The most common differential diagnosis is otosclerosis. Clinical–radiological correlations have therapeutic applications even though the indication for surgery depends on the severity of the vestibular symptoms.

Background The petrous part of the temporal bone plays a crucial role in various cranial surgical approaches, particularly those involving the middle cranial fossa. Understanding the morphometry of this region is essential for minimizing intraoperative risks and enhancing surgical outcomes. This study aims to provide a detailed morphometric analysis of the petrous bone and its anatomical landmarks in an Indian population, addressing a gap in the literature. Methods The study was conducted in the Department of Anatomy andForensic Medicine and Toxicology and involved 100 heads of unclaimed adult bodies that underwent post-mortem examination. Detailed morphometric measurements were taken using ImageJsoftware(National Institutes of Health, Bethesda, MD), focusing on landmarks critical for surgical approaches: the width of the trigeminal ganglion (TG), distances from the medial surface of the posterior root of the zygoma to TG (A), the lateral end of the petrous ridge to TG (B), the arcuate eminence to TG (C), the facial nerve hiatus to TG (D), the foramen spinosum to TG (E), the foramen ovale to TG (F), the superior margin of the internal acoustic meatus to the petrous ridge (G), the lateral end of the petrous ridge to the hiatus for the greater superficial petrosal nerve (GSPN) (H), the foramen spinosum to the foramen ovale (I), and the foramen spinosum to the lateral wall of the middle cranial fossa (J). Data were statistically analyzed using paired sample t-tests and Wilcoxon rank-sum tests. Results Significant differences were observed between the left and right sides for several measurements. The width of the TG averaged 13.57 ± 1.53 mm on the left and 14.20 ± 2.09 mm on the right (p = 0.029). Distances from the medial surface of the posterior root of the zygoma to TG (A) were 33.30 ± 6.26 mm (left) and 33.40 ± 5.52 mm (right) (p = 0.001). The lateral end of the petrous ridge to TG (B) measured 37.90 ± 5.72 mm (left) and 40.30 ± 3.35 mm (right) (p = 0.000). Other significant differences included distances from the arcuate eminence to TG (C), which were 28.50 ± 4.20 mm on the left and 29.60 ± 4.31 mm on the right (p = 0.001); the hiatus for the GSPN to TG (D), which were 11.00 ± 1.00 mm on the left and 10.70 ± 0.81 mm on the right (p = 0.003); and the foramen spinosum to TG (E), which were 12.60 ± 2.24 mm on the left and 11.60 ± 1.92 mm on the right (p = 0.001). Conclusion In summary, this study presents an in-depth morphometric analysis of important landmarks in the petrous bone, revealing notable differences between the left and right sides. These results emphasize the crucial variability that should be considered when planning surgeries involving the middle and posterior cranial fossa.

The online version contains supplementary material available at 10.1007/s12070-024-05052-5.

The ear region has a strong potential for evolutionary studies. While the petrosal bone suffers from ontogeny and allometry, the bony labyrinth provides crucial information for phylogeny. The study of the bony labyrinth itself allowed for argumentation of the early bovid species Eotragus artenensis and Eotragus clavatus being closely related, while a newly described species and genus of early Bovidae from Montréal-du-Gers (France), formerly attributed to Eotragus, clearly belong to another lineage. The morphology of the bony labyrinth of these oldest bovids confirms that Eotragus is a stem Bovidae, while the new Bovidae is more derived. Since the bony labyrinth is a structure that is little affected by ontogeny, allometry, and sexual dimorphism, we propose this structure and its surrounding petrosal bone as the holotype for this new species. This study shows the importance of the ear region in the context of micro- and macro-evolution.

This article describes the approach to the petrous pyramid developed at National Medical Research Center of Otorhinolaryngology, namely an endoscopy – microscopy-guided modified trans-channel infra-promontorium approach with internal carotid artery retraction maneuver in patients with lesions of the petrous pyramid but with preserved hearing. A clinical report describing the apical cholesteatoma of the petrous pyramid and the use of this approach are presented. Anatomical and functional features after the surgery are also described. The purpose of this paper is advancing of the surgical approach to the petrous pyramid with the possibility of hearing preservation. The results of surgical treatment in lesions of the petrous pyramid were evaluated in the immediate and distant periods. The functions of facial mimic muscles were evaluated immediately after the surgery, in 6 months, and in one year. The functions of facial mimic muscles remained at the baseline level during the whole follow-up period. The pure tone audiogram demonstrated the preserved hearing function in the postoperative period. Complete elimination of the pathological process was achieved in all cases (n=15); according to the MRI of the temporal bones, no relapses occurred in a year. The surgical approach proposed for patients with the lesions of the petrous pyramid enables complete removal of the pathological process from the petrous pyramid with the preservation of hearing and facial functions, based on the subjective examinations (audiometry, facial function diagnosis) and radiology (CT and MRI of temporal bones) at the preoperative stage.

A proper sampling strategy is important to obtain sufficient DNA for successful identification of aged skeletal remains. The petrous bone is the highest DNA-yielding bone in the human body. Because DNA extraction from the petrous bone is very destructive, the demand for other DNA sources is significant. When investigating aged skeletal remains, teeth are usually preserved, and recent studies have shown that DNA in teeth can be best preserved in the dental cementum that surrounds the surface of the tooth root. To extract DNA from the surface of the tooth root, a nondestructive method without grinding was used. Petrous bones and teeth from 60 archaeological adult skeletons were analyzed. The DNA yield, degree of DNA degradation, and STR typing success were compared, and the results showed higher DNA yield and higher amplification success in petrous bones, despite higher degradation of petrous bones’ DNA. The greater success of petrous bones is associated with poorly preserved DNA in a quarter of the teeth analyzed. When teeth with badly preserved DNA were excluded from the statistical analysis, no differences in the success of STR loci amplification were observed even if DNA yield was higher in petrous bones, which can be explained by greater degradation of petrous bones’ DNA. When teeth are well preserved, they can be used for genetically analyzing aged skeletal remains instead of petrous bones, and a rapid nondestructive extraction method can be applied to shorten the identification process and to physically preserve the biological specimen.

Abstract Disclosure: A.R. Kasireddy: None. S. Alshami: None. S. Gummalla: None. C. Balasubramaniapandian: None. J.A. Henske: None. A. Albashaireh: None. Background: Pheochromocytomas and paragangliomas are rare neuroendocrine tumors. Catecholamine-secreting paragangliomas, like pheochromocytomas, can present with hypertension, sweating and episodic headaches. Thoughtful consideration must be given to distinguish between the two and potentially avoid a critical misdiagnosis. Case: A 61-year-old woman with hypertension and diabetes presented for evaluation of glomus jugulare discovered on CT of the head during evaluation of worsening hearing loss and tinnitus. She reported a longstanding history of episodic headaches, palpitations, anxiety spells and excessive sweating with more recent onset of ear fullness. When symptoms first presented, she had a left adrenalectomy 3 years prior. CT abdomen at that time showed 1.8 x 2.2 cm left adrenal nodule with a density of 12.2 HU and early contrast washout. Plasma metanephrines were normal but normetanephrines were elevated at 5.1 nmol/L (nl: less than 0.9 nmol/L). 24-hour urine metanephrines were normal but normetanephrines were elevated to 892mcg/24h (nl: 122-676 mcg/24h). MIBG scan was done and showed increased activity in the left adrenal nodule. Decision was made to proceed with left adrenalectomy. Surgical pathology was benign. Present evaluation after discovery of the glomus tumour with worsening symptoms showed normal plasma metanephrines, elevated plasma normetanephrines at 1529.9 pg/ml (0- 285.2 pg/ml), elevated plasma norepinephrine at 3280 pg/ml (0-874 pg/ml), with normal dopamine and epinephrine levels. CT head showed a 3 x 2.7 x 2.1 cm lytic destructive mass within the petrous temporal bone at the left skull base containing multiple internal calcifications. Given the lab and imaging findings, paraganglioma was diagnosed. Genetic testing revealed SDHB mutation. Neurosurgery consultants determined that the tumour was not amenable to resection. She was treated with radiation therapy, alpha blockade, and close blood pressure monitoring. Discussion: This case highlights the importance of reviewing the degree of hormonal elevations as well as the pattern of elevation to obtain a correct diagnosis. Paragangliomas commonly secrete normetanephrines rather than metanephrines and are often not immediately localized. Understanding the most likely genetic mutations when a paraganglioma is suspected can direct appropriate choice of radionuclide scanning agents. In this case, an earlier diagnostic scan may have prevented unnecessary adrenalectomy and facilitated earlier discovery of the paraganglioma. Presentation: 6/2/2024

Abstract Introduction: Lesions in the petrous apex region present a significant challenge for surgeons due to the deep location at the skull base and complex anatomical relations. The Kawase approach, or partial resection of the anterior petrous temporal bone, though widely adopted worldwide, remains under-researched in Vietnam. Patients and Methods: A cross-sectional descriptive study was conducted on 25 patients treated surgically using the Kawase approach at Viet Duc University Hospital from January 2022 to May 2024 Results: The average age was 53.9 years, with a male/female ratio of 1/5,25. Clinical symptoms included: Trigeminal nerve pain/numbness (60%), headaches (52%), and dizziness (40%). Regarding the histopathology aspect, there were Meningiomas (16), Trigeminal schwannomas (6), Chordomas (2), Teratoma (1). The average tumor size was 28 ±11.3mm. Ability of complete tumor resection were: total resection (14 cases), subtotal (4 cases), partial (6 cases), unresectable and biopsy only (1 case). The per-operative and postoperative complication rates accounted for 12%, however, no mortality was observed in this series. Conclusions: The Kawase approach is a safe and effective method for accessing tumors in the petrous apex region. Keywords: Petrous apex, Kawase approach, petrous bone – clivus.

The anterior transpetrosal approach using a microscope to provide wider access to the petrous apex region has been described for radical resection of lesions of the middle and posterior skull base. The microscopic anterior transpetrosal approach (mATPA) requires a wide craniotomy and meticulous epidural procedures to minimize temporal lobe retraction. Recently, the clinical application of transcranial endoscopic keyhole approaches for minimally invasive surgery has been steadily expanding. In this study, the details of the purely endoscopic subtemporal keyhole ATPA (eATPA) for petrous apex lesions are described and its initial results are reported. Between May 2022 and May 2023, the authors performed eATPA in 10 patients with petrous apex lesions, of which 6 were meningiomas, 3 were trigeminal schwannomas, and 1 was epidermoid cyst. The surgical procedure of the purely eATPA is as follows. After a small temporal craniotomy, the endoscopic procedure is started. The anterior rim of the petrous bone and Meckel's cave are exposed via an intradural subtemporal approach. The lesion is removed with additional drilling of Kawase's triangle, cutting the superior petrosal sinus, opening Meckel's cave, and cutting the tentorium. The authors also compared the outcomes of mATPA versus eATPA for consecutive cases of petrous apex lesions. Gross-total resection was achieved in 8 of the 10 patients. The average operative time was 4 hours 13 minutes. There were 3 cases of transient abducens nerve palsy and 1 case of trochlear nerve palsy in the postoperative period. No new-onset motor deficits or CSF leakage was noted in any of these patients. Only 1 patient exhibited postoperative asymptomatic temporal lobe edema. The Karnofsky Performance Scale (KPS) scores remained unchanged or improved for all patients postoperatively. Compared with mATPA, eATPA achieved a similar extent of resection and comparable postoperative KPS scores with a significantly shorter mean operative time, much smaller temporal craniotomy, and thus less mean blood loss during surgery with lower rates of new-onset temporal lobe edema in the postoperative period. An eATPA allows a direct route to access Meckel's cave and posterior cranial fossa lesions similar to conventional mATPA, with shortening the operative time and reducing the risk of postoperative temporal lobe edema. This eATPA is considered one of the new surgical techniques that can be expected to develop in the future.

To analyze the clinical features and surgical outcomes of patients with endolymphatic sac tumors (ELSTs). Single institution retrospective cohort study. The clinical data of 29 patients with 30 ELSTs who underwent surgery were retrospectively reviewed. Information on patient demographics, tumor size and grade, intraoperative blood loss volume, hearing and facial nerve outcomes, and follow-up data was collected and analyzed. The main symptoms were hearing loss in 26 ELSTs (86.7%) and tinnitus in 17 (56.7%). Twenty-four (80%) ELSTs were in advanced stages (Grade III). The median tumor volume was 6.35 cm3. The median intraoperative blood loss volume was 300 mL. Facial nerve function was well preserved in 21 patients. Among all patients with Grade III tumors, 12 patients underwent tension-free anterior facial nerve rerouting, and 11 patients (91.7%) maintained good facial nerve function postoperatively (HB I and HB II). Only one patient exhibited permanent vocal cord paralysis, and no patients experienced cerebrospinal fluid (CSF) leakage postoperatively. Gross total resection was achieved in 22 patients (73.3%), 5 patients (16.7%) experienced tumor recurrence, and 3 (10%) had residual tumors. Most ELSTs tend to be diagnosed in the advanced stage. Tension-free anterior facial nerve rerouting could maximally preserve facial nerve function. The intraoperative blood loss volume was associated with tumor size and stage. Tumor recurrence tends to occur at the posterior edge of the petrosal bone, internal auditory canal, and surface of the posterior fossa. Given the relatively high recurrence rate of ELSTs, long-term follow-up is recommended. 4 Laryngoscope, 135:339-344, 2025.

The Late Bronze Age is characterized by the increasing homogenization of material culture and the prevalence of urn burials. The cemetery of Inzersdorf, located in the Lower Traisen Valley, Austria, is used to investigate whether changes in burial practices during the Late Bronze Age were locally driven or influenced by external factors. This study interprets strontium isotope data from 215 calcined human bone samples in the context of a local baseline established from 163 modern plant samples (55 locations) within a 10 km radius of Inzersdorf. Complementary Correspondence Analysis and 14C dates were used to identify chronological changes. The high-density sampling carried out in the Traisen Valley for bioavailable strontium (BASr) enabled the differentiation of people who mainly sourced their food from the valley or the hills. A diachronic shift in land use was identified, with the main food resource obtained from the hills for the earlier and the valley providing most of the foods for the later phase of the cemetery, which is more distinct in men than in women. Five individuals with isotopic values that differed from the main population were identified, one of which has an 87Sr/86Sr of 0.7061 falling below the BASr baseline created with the modern plant data. While the latter may indicate metal-related travel, the other four individuals may be interpreted as inhabitants of single farmsteads. Additionally, an individual with a significant shift in isotopic values between the petrous bone and long bone was identified, indicating changing local food sources over the individual’s life.

Dose assessment in petrous bone CT: Effect of tube current modulation and scan length

Introduction. Endoscopic ear surgery is a promising treatment for petrous bone cholesteatoma in children. Endoscopic assistance provides better visualization and the ability to manipulate in hidden areas of the formed cavity and facilitate the removal of cholesteatoma matrix from hard-to-reach areas.Aim. o systematize the accumulated knowledge about the clinical presentations of cholesteatoma of the temporal bone pyramid in children, review the modern methods of treatment and possible complications, and assess the necessity of applying endoscopic imaging devices to monitor hard-to-reach places in the temporal bone pyramid.Materials and methods. The results of surgical treatment of petrous bone cholesteatoma (PBC) in the immediate and long-term postoperative periods in children were assessed. The study included 26 children aged 8 to 18 years (average age 13.1), 21 boys and 5 girls. Dynamic follow-up after surgery was at least two years. The function of facial muscles was assessed using the House – Brackmann scale before and after surgery after 6 months, and a pure-tone audiogram was performed before and after surgery after 6 months. The approaches, options for completing the operation, complications, and relapse rates are presented.The discussion of the results. In the postoperative period, 2 people (7.7%) had normal hearing according to audiometry results, 1 (3.8%) had I degree of hearing loss, 5 (19.2%) had II degree of hearing loss, 6 (23.0%), III degree of hearing loss, in 7 (27.0%) IV degree of hearing loss, in 5 (19.2%) deafness. Function in the postoperative period was normal in 15 (57.0%) and from House – Brackmann grades II to VI in 11 (43.0%). Recurrence of cholesteatoma was detected in eight patients (30.0%) after 1–2 years.Conclusion. In children, early diagnosis of cholesteatoma of the petrous bone is important to prevent the risk of complications. The use of endoscopic assistance when removing cholesteatoma of the petrous bone provides advantages: the ability to remove the cholesteatoma matrix in hidden areas, provides a larger viewing angle and control of these areas, thereby minimizing the risks of intraoperative complications, allowing for maximum sanitization of the pathological process.