Inflammatory diseases of the petrous bone

Symptom: Unilateral Facial Paralysis

Assessment of the distribution and volume of air chambers around the inner auditory canal on high-resolution computed tomography scans of the temporal bone.

Symptoms: Clogged Ears and Muffled Hearing

Objective The purpose of this study was to dissect these structure existed in petrous portions of the temporal bones and the posterior fossa nearby,to measure the distence of those important stuctures around the superior petrosal venous (SPV), to propose the patterns of drainage of the SPV along the petrous ridge in relation to the Meckel cave and internal acoustic meatus (IAM) and to delineate its effect on the surgical exposures obtained in subtemporal transtentorial and retrosigmoid suprameatal approaches. Methods Ten adult cadaveric heads (20 hemispheres) were studied, and data of SPV and the structures around were measured. The patterns of drainage of the SPV along the petrous ridge were characterized according to their relation to the Meckel cave and the IAM based on an examination of 20 hemispheres. Subtemporal trans-tentorial and retrosigmoid suprameatal approaches were performed in two additional cadavers to demonstrate the effect of the drainage pattern on the surgical exposures. Result The SPV originated from the cerebellopontine angle cistern, and were multibranch. According to SPV relationship with the Meckel cave and internal acoustic meatus (IAM), the patterns of drainage of the SPV were classified into three groups. Type Ⅰ emptied into the SPS above or medial to the Meckel cave. The most common type-Type Ⅱ, emptied between the lateral limit of the trigeminal nerve at the Meckel cave and the medial limit of the facial nerve at the IAM. Type Ⅲ emptied into the SPS above and lateral to the boundaries of the IAM Conclusions The site which the SPV emptied into the superior petrosal sinus (SPS) was relationship tightly with the Meckel cave and IAM. According to SPV relationship with the Meckel cave and internal acoustic meatus (IAM). The proposed modified classification system and its effect on the surgical exposure may aid in planning the approach directed along the petrous apex and may reduce the probability of venous complications. Key words: Superior petrosal vein; Superior petrosal sinus; Retrosigmoid approach; Subtemporal approach

What's Your Diagnosis? Symptoms: Middle Ear Mass and Unilateral Hearing Loss

Symptom: Unilateral Hearing Loss

The temporal bone is made up of three bones: the tympanic, squamous, and petrous bones. It contains three cavities: the external auditory meatus, the middle ear or tympanic cavity, the inner ear or labyrinth, and, more medially, the internal auditory meatus. The facial nerve is located within the temporal bone: first in the internal auditory meatus, between the anterior and posterior labyrinth, and then between the inner and middle ear. The VIIIth and VIIth cranial nerves are located in the internal auditory meatus. The VIth cranial nerve runs close to the anterior part of the petrous apex. The mixed nerves (IX–XI) are located in the anterior part of the jugular foramen.

Symptoms: Sudden Sensorineural Hearing Loss and Aural Fullness

The patient’s imaging features, especially the honeycomb pattern of ossific changes in the geniculate fossa, were virtually pathognomonic for ossifying hemangioma of the facial nerve.

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

A quick method to expose the structures and relations of the middle ear and inner ear by cadaveric dissection

Symptoms: Purple Ear Drum and Hearing Loss

Understanding the underlying pathophysiology and the patterns of disease spread is crucial in accurate image interpretation. In this pictorial review, the common and important inflammatory processes of the temporal bone in children will be discussed, and key computed tomography (CT) and magnetic resonance imaging (MRI) features described. Inflammatory processes are categorized by anatomical location: the petrous apex and the inner, middle and outer ear. A complete review of the literature is provided. Cholesteatoma, cholesterol granuloma and mucoceles are inflammatory processes that occur across the anatomical subsites of the temporal bone, whilst site-specific inflammatory processes include labyrinthitis ossificans in the inner ear and keratosis obturans in the external ear. Infection is a key cause of inflammation in the temporal bone, and specific infections include petrous apicitis, otitis media and necrotizing otitis externa. Finally, important mimics and do-not-touch lesions are considered. CT and MRI are complementary in assessing these disorders, as two of the most important diagnostic clues are the presence of bone erosion, best appreciated on CT, and true diffusion restriction as seen on MRI. Flow charts to assist in the diagnosis of paediatric temporal bone inflammatory disease are also provided. Paediatric temporal bone inflammatory processes are common and can have severe clinical sequelae. Timely intervention, facilitated by correct radiological diagnosis, can often prevent progression of disease, loss of hearing and systemic illness.

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.

Symptom: Postauricular Mass