Percutaneous transluminal angioplasty (PTA) and stenting have been used for the treatment of internal carotid artery (ICA) stenosis over the past two decades. A systematic review was performed to understand the efficacy of PTA and/or stenting for petrous and cavernous ICA stenosis. In total, 151 patients (mean age 64.9) met criteria for analysis, 117 (77.5%%) were male and 34 (22.5%) were female. Of the 151 patients, 35 of them (23.2%) had PTA, and 116 (76.8%) had endovascular stenting. Twenty-two patients had periprocedural complications. There was no significant difference in the complication rates between the PTA (14.3%) and stent (14.7%) groups. Distal embolism was the most common periprocedural complication. Average clinical follow up for 146 patients was 27.3 months. Eleven patients (7.5%) out of 146 had retreatment. The treatment of petrous and cavernous ICA with PTA and stenting has relatively significant procedure related complication rates and adequate long-term patency.

The endoscopic endonasal approach (EEA) is increasingly utilized for management of petrous apex cholesterol granuloma (PACG). Surgical goals include drainage and marsupialization of the cyst. Various techniques have been described to try to reduce the rates of recurrence. We studied the effect of mucosal grafting on recurrence.
Retrospective Cohort study.
Patients who underwent EEA for PACG at two tertiary care centers between 1999 and 2018 were identified and divided into two cohorts: Mucosal versus no mucosal reconstruction. Surgical approach, reconstructive method, and recurrence were recorded. Primary endpoint was symptomatic or radiographic recurrence.
Thirty-four patients were identified undergoing 37 surgeries. Four patients developed recurrences of which three elected to undergo revision. Some form of mucosa was used to line the drainage tract in 20 cases. A free mucosal graft was used in 8, and a small customized nasal septal flap (miniflap) in 12. All four recurrences occurred in cases where no mucosa was used, demonstrating decreased recurrences with mucosal reconstruction (P < .05). There was no difference found between free mucosal grafts and miniflaps.
Utilization of mucosa to partially line a circumferentially de-epithelialized drainage pathway after EEA for PACG reduce recurrence rates.
3 Laryngoscope, 131:E2513-E2517, 2021.

Cerebellopontine angle (CPA) meningiomas arise from the petrous face of the temporal bone, which forms the lateral boundary of the CPA. They can be categorized into anterior, middle, and posterior, based on their attachment in relation to the internal acoustic meatus. Each of them presents with their own characteristic clinical syndromes. Because of their close proximity to neurovascular structures, they pose a challenge during surgery. Microsurgery remains the primary treatment modality for large and symptomatic meningiomas. The retrosigmoid approach provides an ideal access for most of the tumors in this location. Radiosurgery is the primary modality of adjuvant therapy for residual, recurrent, and small lesions. Fully fractionated external beam radiotherapy can be used for larger, broader-based residual/recurrent tumors. Management of these complex lesions should include patient preferences and a team approach, including a skull base neurosurgeon, neurotologist, and radiation oncologist.

UNASSIGNED: Petrous apex cephaloceles are characterized by herniation of Meckel\'s cave into the petrous apex. An extensive review of the literature reveals 20 cases of bilateral petrous apex cephaloceles. This article reports an additional case of bilateral petrous apex cephaloceles and reviews the pertinent literature.
METHODS: A 64-year-old female was referred from a primary care clinic due to longstanding headache. A non-enhanced CT scan of the brain revealed osteolytic bony lesions at the petrous apices and an empty sella. A brain MRI with contrast showed CSF-containing lesions in the petrous apices, communicating with Meckel\'s cave bilaterally. The patient was managed conservatively and is currently followed up in the neurosurgery clinic.
CONCLUSIONS: While the exact etiology remains uncertain, petrous apex cephaloceles are postulated to originate from sustained, chronic elevation of intracranial pressure. On MRI, petrous apex cephaloceles display signal intensities resembling CSF throughout all sequences. They demonstrate well-defined margins continuous with Meckel\'s cave. CT scans allow further characterization, i.e. invasive erosions, of the osseous structures in patients with petrous apex cephaloceles.
CONCLUSIONS: A thorough understanding of the petrous apex anatomy and its pathological lesions is paramount. A brain MRI remains the diagnostic imaging of choice to characterize petrous apex cephaloceles.

Advances in NGS sequencing technologies, improved laboratory protocols and new bioinformatic workflows have seen huge increases in ancient DNA (aDNA) research on archaeological materials. A large proportion of aDNA work now utilizes the petrous portion of the temporal bone (pars petrosa), which is recognized as an excellent skeletal element for long-term ancient endogenous (host) DNA survival. This has been significant due to the often low endogenous content of other skeletal elements, meaning that large amounts of sequencing are frequently required to obtain sufficient genetic coverage. However, exclusive sampling of the petrous for aDNA analysis introduces a new set of potential biases into our scientific studies - and these issues are yet to be considered by ancient DNA researchers. This paper aims to outline the possible biases of utilizing petrous bones to undertake aDNA analyses and highlight how these complications may potentially be overcome in future research.

OBJECTIVE: Petrous internal carotid aneurysm (PA) concomitant with a mass lesion and cranial nerve palsy is relatively rare. Flow-diverter stent implantation is now widely used as an alternative treatment for PA. However, alternative treatments sometimes cannot be used because of tortuosity of the carotid artery, allergies to contrast material, and high costs. The outcomes of different treatment methods should therefore be assessed. Here, we review the available literature on treatments for PA.
METHODS: In a search using the terms \"aneurysm\", \"carotid artery\", and \"petrous\" on PubMed, MEDLINE, and databases such as OvidSP, 221 articles were identified. We also performed a literature review and discuss and compare the causes, symptoms, treatment methods, and clinical outcomes of PA.
CONCLUSIONS: Onset of secondary aneurysm was generally heralded by bleeding (p<0.001), while onset of primary aneurysm was heralded by cranial nerve deficit (p= 0.0014). Outcomes after treatment of 34 cranial nerve palsies in 25 patients are reported.

Direct approaches to high cervical lesions, including tumors and aneurysms, carry significant risks. This renders alternative approaches desirable, with vascular disease amenable to exclusion and revascularization to the intracranial circulation, including the petrous or supraclinoid segments of the internal carotid artery (ICA). The cervicopetrous ICA bypass via saphenous venous grafting has proven an effective strategy for treating and excluding these lesions. In current practice, this is performed via an extradural subtemporal approach to access the petrous segment of the ICA and a cervical incision for access to the cervical ICA. The venous graft is alternately tunneled subcutaneously or in situ through the cervical ICA, with the latter eschewing external compression, kinking, and torsion, which increases risk of graft thrombosis with the former. Maxillary or middle meningeal arteries may also serve as donors to the petrous ICA. Moreover, the petrous ICA may be used as a donor in revascularization procedures, to the supraclinoid segment of the ICA and the middle cerebral artery, with petrous supraclinoid and petrous-MCA bypasses described. Clinical utility and operative approaches bypassing to or from the petrous ICA in revascularization procedures are reviewed and discussed.

Petrous internal carotid artery (ICA) aneurysms are rare and pose a unique management dilemma. They are most commonly fusiform. They are difficult to treat surgically and typically not amenable to selective aneurysmal obliteration. The advent of flow diverters, such as the Pipeline endovascular device, has offered a new approach to these historically challenging lesions. The unique utility of flow diversion in treatment of petrous ICA aneurysms is reviewed and discussed.

Petrous internal carotid artery (ICA) aneurysms are rare, complicated lesions to treat. The management paradigms include observation, endovascular exclusion, or surgical trapping with or without revascularization. The case described in this video involved a 67-yr-old woman with a known history of chronic lymphocytic leukemia, who presented after a mechanical ground-level fall. Clinically, she had a nasal deformity and resolving epistaxis consistent with mild facial trauma. Computed tomography (CT) revealed a comminuted nasal bone fracture and an incidental 3-cm right petrous ICA aneurysm. Subsequent vascular imaging demonstrated a concurrent 1.5-cm right cervical ICA dissecting pseudoaneurysm. Flow diversion with a Pipeline stent (Medtronic, Dublin, Ireland) was unsuccessful because the aneurysm\'s size precluded microcatheter selection of the ICA distal to the lesion. When the patient did not tolerate balloon test occlusion of the ICA, we proceeded with surgical trapping of both aneurysms and high-flow extracranial-to-intracranial bypass. The patient underwent a right frontotemporal craniotomy and an external carotid artery-to-frontal M2 middle cerebral artery bypass with a radial artery graft. Following a clinoidectomy, an aneurysm clip was applied to the paraclinoid ICA, and the cervical ICA was ligated just distal to the bifurcation, effectively trapping both aneurysms. The patient tolerated the procedure well. Postoperatively, she experienced symptomatic hypotension requiring vasopressor therapy and a transient partial oculomotor palsy that resolved during her hospital course. She was discharged home without neurological sequelae. Postoperative CT angiography demonstrated complete exclusion of the ICA aneurysms and a patent radial bypass graft after surgery and at 6-month follow-up. The patient provided consent for publication.

BACKGROUND: Learning surgical anatomy of the petrous pyramid can be a challenge, especially in the beginning of the training process. Providing an easier, holistic approach can be of help to everyone with interest in learning and teaching skull base anatomy. We present the complex organization of petrous pyramid anatomy using a new compartmental approach that is simple to understand and remember.
METHODS: The surfaces of the petrous pyramid of two temporal bones were examined; and the contents of the petrous pyramid of 8 temporal bones were exposed through progressive drilling of the superior surface.
RESULTS: The petrous pyramid is made up of a bony container, and its contents were grouped into 4 compartments (mucosal, cutaneous, neural, and vascular). Two reference lines were identified (mucosal and external-internal auditory canal lines) intersecting at the level of the middle ear. The localization of contents relative to these reference lines was then described, and 2 methods of segmentation (the X method and the V method) were then proposed. This description was then used to describe middle ear relationships, facial nerve anatomy, and air cell distribution.
CONCLUSIONS: This new compartmental approach allows a comprehensive understanding of the distribution of petrous pyramid contents. Dividing it into anatomic compartments, and then navigating this mental map along specific reference points, lines, spaces, and segments, could create a useful tool to teach or learn its complex tridimensional anatomy.