Aneurysmal bone cyst of the temporal bone presenting with reversible vestibular impairment

BACKGROUND

Aneurysmal bone cysts are expansile benign lesions associated with compressive destruction and obscure pathogenesis. The most common sites of temporal bone involvement are the petrous apex, squamous portions and mastoid.

CASE REPORT

This paper reports a right temporal aneurysmal bone cyst in a 51-year-old man who presented clinically with facial palsy, and hearing loss and impaired vestibular function. Magnetic resonance imaging and computed tomography findings were consistent with a diagnosis of aneurysmal bone cyst. Inter-operative findings showed that the lesion had caused compressive damage to the internal auditory canal. Following surgical excision, the patient experienced vertigo, indicating recovery of vestibular function. Follow-up imaging revealed complete resection without clinical recurrence.

CONCLUSION

To our knowledge, this is the first report of aneurysmal bone cyst invasion of the inner auditory canal. Our clinical experience indicates that vestibular nerve damage recovery is relatively uncommon. This case report will hopefully inform future studies.

Focal meato-mastoid fistula closure using bony sigmoid sinus plate

OBJECTIVE

This study aimed to analyse the effectiveness of using the bony sigmoid sinus plate for repair of meato-mastoid fistulae.

METHOD

A retrospective study of all cases between January 2013 and December 2019 at our secondary-tertiary centre was conducted. Inclusion criteria for study were: (1) cases with focal meato-mastoid fistulae and (2) focal meato-mastoid fistulae that were repaired by using bony sigmoid sinus plate using the bony sigmoid sinus plate technique. There were 13 cases that fulfilled these criteria.

RESULTS

The outcome of the repair of meato-mastoid fistulae with bony sigmoid sinus plate was very encouraging. All 13 cases did well. Two patients had delayed epithelialisation at 9 and 12 months after surgery.

CONCLUSION

The technique of repairing meato-mastoid fistulae by using bony sigmoid sinus plate is simple, repeatable and provides effective physiological reconstruction of the posterior canal wall. Bony sigmoid sinus plate is easily and locally available in all cases undergoing cortical mastoidectomy. This plate of bone has a curvature, consistency and structure that match well with that of the posterior or superior canal wall. In addition, this technique is cost-effective with good patient compliance.

Radiological dimensions of the Eustachian tube in patients with adhesive otitis media

OBJECTIVE

This study aimed to analyse the computed tomography parameters for effective ventilation in patients with adhesive otitis media.

METHODS

Twenty-six patients with unilateral adhesive otitis media were included in the study. The patients' temporal bone computed tomography images were retrospectively reviewed. Eustachian tube length and diameter were measured. Mastoid pneumatisation and middle-ear size were evaluated by measuring petroclival and Eustachian tube-tympanic cavity ventilation angles.

RESULTS

The average Eustachian tube length was 38.4 mm and 38.9 mm in adhesive otitis media and healthy ears, respectively. The Eustachian tube diameter of the adhesive otitis media ears (1.47 mm) was significantly narrower than that of the healthy ears (1.83 mm). There were no significant differences in the angles between adhesive otitis media and healthy ears.

CONCLUSION

A narrow Eustachian tube diameter was associated with developing adhesive otitis media. Measuring Eustachian tube diameter is simple and can be routinely performed when examining temporal bone computed tomography images for Eustachian tube function evaluation.

Automated summative feedback improves performance and retention in simulation training of mastoidectomy: a randomised controlled trial

OBJECTIVE

This study aimed to investigate the effects of automated metrics-based summative feedback on performance, retention and cognitive load in distributed virtual reality simulation training of mastoidectomy.

METHOD

Twenty-four medical students were randomised in two groups and performed 15 mastoidectomies on a distributed virtual reality simulator as practice. The intervention group received additional summative metrics-based feedback; the control group followed standard instructions. Two to three months after training, participants performed a retention test without learning supports.

RESULTS

The intervention group had a better final-product score (mean difference = 1.0 points; p = 0.001) and metrics-based score (mean difference = 12.7; p < 0.001). At retention, the metrics-based score for the intervention group remained superior (mean difference = 6.9 per cent; p = 0.02). Also at the retention, cognitive load was higher in the intervention group (mean difference = 10.0 per cent; p < 0.001).

CONCLUSION

Summative metrics-based feedback improved performance and lead to a safer and faster performance compared with standard instructions and seems a valuable educational tool in the early acquisition of temporal bone skills.

Quantitative analysis of tegmen bone mineral density in obese and non-obese patients

BACKGROUND

Certain factors have been linked to lateral skull base demineralisation or erosion, which may predispose to spontaneous cerebrospinal fluid leak. There are relatively few quantitative reports of skull base changes in patient populations.

METHOD

A novel refined measurement algorithm for quantification of tegmen bone mineral density was developed, and bone mineral density between obese and non-obese patient groups was compared. Computed tomography scans were analysed by three blinded reviewers, and tegmen bone mineral densities were compared.

RESULTS

There were 23 patients in the obese group and 27 matched controls in the non-obese group. Inter-rater reliability was 'strong' to 'near complete' (κ = 0.75-0.86). No differences in tegmen bone mineral density were found between the groups (p = 0.64). The number of active blood pressure medications correlated positively with lateral skull base bone mineral density.

CONCLUSION

A novel, refined, quantitative measurement algorithm for the assessment of tegmen bone mineral density was developed and validated. Obesity was not found to significantly affect tegmen bone mineral density.

Lateral temporal bone resection for cutaneous carcinomas of the external auditory canal and peri-auricular region

OBJECTIVES

To evaluate the outcomes for patients after lateral temporal bone resection surgery for cutaneous squamous cell carcinoma and basal cell carcinoma, and to ascertain predictors of survival and treatment failure.

METHODS

A retrospective review was conducted of the medical records for all patients who underwent lateral temporal bone resection for cutaneous squamous cell carcinoma or basal cell carcinoma between 2007 and 2019 in Western Australia.

RESULTS

Thirty-seven patients underwent lateral temporal bone resection surgery. Median follow-up duration was 22 months. Twenty-five patients had squamous cell carcinoma and 12 had basal cell carcinoma. The overall survival rate at two years for patients with squamous cell carcinoma was 68.5 per cent. Pre-operative facial nerve involvement (determined via clinical or radiological evidence) was identified as a predictor of mortality (hazard ratio = 3.411, p = 0.006), with all patients dying before two years post-operatively. Locoregional tumour control was achieved in 81 per cent of cases (n = 30).

CONCLUSION

Lateral temporal bone resection offers acceptable local control rates and survival outcomes. Caution should be used in offering this surgery to patients with clinical or radiological evidence of facial nerve involvement because of the relatively poorer survival outcomes in this subgroup.

Petrous bone cholesteatoma: our experience of 20 years and management of two giant cases affecting rhinopharynx

PURPOSE

To demonstrate our experience in the treatment of petrous bone cholesteatoma (PBC).

METHODS

Data of PBC patients in our hospital from January 2000 to December 2019 were collected. Surgical approaches and facial function were mainly discussed and compared with the literature. The management of 2 giant PBC cases affecting rhinopharynx has been demonstrated.

RESULTS

The supralabyrinthine type was the most frequent type followed by the massive type. There were 5 cases with cholesteatoma extending into the clivus (2 cases), sphenoid (1 case) and rhinopharynx (2 cases). The translabyrinthine approach (40%) was our most frequently used approach followed by the middle fossa approach (36%) and the transmastoid approach (11%). There were 10 cases managed with the assistance of endoscope, including 3 cases with cholesteatoma extending into clivus, sphenoid and rhinopharynx separately. Obliteration of the cavity was performed in 70.3% (135/192) cases; 3 of them recurred. For the 2 giant PBC cases affecting rhinopharynx, traditional microscopic surgery assisted with transnasal endoscope was performed. The reduced exposure was beneficial for postoperative recovery, and the approach in the nasal cavity provided a permanent drainage for postoperative examination.

CONCLUSION

Otologic endoscope combined with traditional microscopic surgery could reduce the exposure in surgery. For extremely extended cases of PBC, supplementary transnasal endoscopic approach deserves to be considered for the traditional temporal bone approach.

Radiological findings in spontaneous cerebrospinal fluid leaks of the temporal bone

BACKGROUND AND OBJECTIVE

Spontaneous cerebrospinal fluid leak of the temporal bone is an emerging clinical entity for which prompt and accurate diagnosis is difficult given the subtle signs and symptoms that patients present with. This study sought to describe the key temporal bone abnormalities in patients with spontaneous cerebrospinal fluid leak.

METHODS

A retrospective cohort study was conducted of adult patients with biochemically confirmed spontaneous cerebrospinal fluid leak. Demographics and radiological features identified on computed tomography imaging of the temporal bones and/or magnetic resonance imaging were analysed.

RESULTS

Sixty-one patients with spontaneous cerebrospinal fluid leak were identified. Fifty-four patients (88.5 per cent) underwent both temporal bone computed tomography and magnetic resonance imaging. Despite imaging revealing bilateral defects in over 75 per cent of the cohort, only two patients presented with bilateral spontaneous cerebrospinal fluid leaks. Anterior tegmen mastoideum defects were most common, with an average size of 2.5 mm (range, 1-10 mm).

CONCLUSION

Temporal bone computed tomography is sensitive for the identification of defects when suspicion exists. In the setting of an opacified middle ear and/or mastoid, close examination of the skull base is crucial given that this fluid is potentially cerebrospinal fluid.

Surgical considerations during cochlear implantation: the utility of temporal bone computed tomography

OBJECTIVE

This paper describes the construction of portals for electrode placement during cochlear implantation and emphasises the utility of pre-operative temporal bone three-dimensional computed tomography.

METHODS

Temporal bone three-dimensional computed tomography was used to plan portal creation for electrode insertion.

RESULTS

Pre-operative temporal bone three-dimensional computed tomography can be used to determine the orientation of temporal bone structures, which is important for mastoidectomy, posterior tympanotomy and cochleostomy, and when using the round window approach.

CONCLUSION

It is essential to create appropriate portals (from the mastoid cortex to the cochlea) in a step-by-step manner, to ensure the safe insertion of electrodes into the scala tympani. Pre-operative three-dimensional temporal bone computed tomography is invaluable in this respect.

Quantification of biomaterial dispersion during otologic procedures and role of barrier drapes in Covid 2019 era - a laboratory model

BACKGROUND

Aerosol generation during temporal bone surgery caries the risk of viral transmission. Steps to mitigate this problem are of particular importance during the coronavirus disease 2019 pandemic.

OBJECTIVE

To quantify the effect of barrier draping on particulate material dispersion during temporal bone surgery.

METHODS

The study involved a cadaveric model in a simulated operating theatre environment. Particle density and particle count for particles sized 1-10 μ were measured in a simulated operating theatre environment while drilling on a cadaveric temporal bone. The effect of barrier draping to decrease dispersion was recorded and analysed.

RESULTS

Barrier draping decreased counts of particles smaller than 5 μ by a factor of 80 in the operating theatre environment. Both particle density and particle count showed a statistically significant reduction with barrier draping (p = 0.027).

CONCLUSION

Simple barrier drapes were effective in decreasing particle density and particle count in the operating theatre model and can prevent infection in operating theatre personnel.

'Black Bone' magnetic resonance imaging as a novel technique to aid the pre-operative planning of posterior tympanotomy for cochlear implantation

Purpose: 'Black Bone' magnetic resonance imaging (BB MRI) is a novel sequence developed as an alternative to computed tomography (CT) for osseous imaging. We explored its potential utilisation in the pre-operative surgical planning of posterior tympanotomy for cochlear implantation through depiction of the mastoid facial nerve (mFN) canal and the posterior canaliculus of the chorda tympani (ChT), thus defining the facial recess. Methods: Twenty five adult patients were prospectively imaged with a dedicated BB MRI sequence. A consensus qualitative BB MRI 'visibility score' for the confidence of demonstration of the mFN canal and the posterior canaliculus of the ChT was recorded, as well as a 'corresponding score' to determine whether the neural structures on BB MRI corresponded to the paths of the nerves on a previous CT study. Results/discussion: The BB MRI sequence was able to clearly delineate the course of mFN in 100% of cases and that of ChT in 72%, with their courses corresponding to those depicted on CT in almost all cases. Maximum intensity projections with 7 mm slabs provided the optimal simultaneous demonstration of mFN, ChT and round window along the posterior tympanotomy surgical approach. Conclusion: The proposed BB MRI sequence reliably depicts mFN and ChT in the majority of cases, with a performance comparable to that of CT. It is proposed that it will be a useful adjunct to MRI protocols as part of cochlear implant assessment in those centres where CT is not routinely performed.

Cochlear nerve canal stenosis and associated semicircular canal abnormalities in paediatric sensorineural hearing loss: a single centre study

OBJECTIVE

This study aimed to evaluate the association between cochlear nerve canal dimensions and semicircular canal abnormalities and to determine the distribution of bony labyrinth anomalies in patients with cochlear nerve canal stenosis.

METHOD

This was a retrospective study in which high-resolution computed tomography images of paediatric patients with severe-to-profound sensorineural hearing loss were reviewed. A cochlear nerve canal diameter of 1.5 mm or less in the axial plane was classified as stenotic. Semicircular canals and other bony labyrinth morphology and abnormality were evaluated.

RESULTS

Cochlear nerve canal stenosis was detected in 65 out of 265 ears (24 per cent). Of the 65 ears, 17 ears had abnormal semicircular canals (26 per cent). Significant correlation was demonstrated between cochlear nerve canal stenosis and semicircular canal abnormalities (p < 0.01). Incomplete partition type II was the most common accompanying abnormality of cochlear nerve canal stenosis (15 out of 65, 23 per cent).

CONCLUSION

Cochlear nerve canal stenosis is statistically associated with semicircular canal abnormalities. Whenever a cochlear nerve canal stenosis is present in a patient with sensorineural hearing loss, the semicircular canal should be scrutinised for presence of abnormalities.

High-resolution computed tomography evaluation of congenital aural atresia - how useful is this?

OBJECTIVE

To depict various temporal bone abnormalities on high-resolution computed tomography in congenital aural atresia patients, and correlate these findings with auditory function test results and microtia subgroup.

METHODS

Forty patients (56 ears) with congenital malformation of the auricle and/or external auditory canal were evaluated. Auricles were graded according to Marx's classification, divided into subgroups of minor (grades I and II) and major (III and IV) microtia. Other associated anomalies of the external auditory canal, tympanic cavity, ossicular status, oval and round windows, facial nerve, and inner ear were evaluated.

RESULTS

Minor and major microtia were observed in 53.6 and 46.4 per cent of ears respectively. Mean hearing levels were 62.47 and 62.37 dB respectively (p = 0.98). The malleus was the most commonly dysplastic ossicle (73.3 vs 80.8 per cent of ears respectively, p = 0.53). Facial nerve (mastoid segment) abnormalities were associated (p = 0.04) with microtia subgroup (80 vs 100 per cent in minor vs major subgroups).

CONCLUSION

Microtia grade was not significantly associated with mean hearing levels or other ear malformations, except for external auditory canal and facial nerve (mastoid segment) anomalies. High-resolution computed tomography is essential in congenital aural atresia, before management strategy is decided.

A retrospective review and multi-specialty, evidence-based guideline for the management of necrotising otitis externa

BACKGROUND

Necrotising otitis externa is a progressive infection of the external auditory canal which extends to affect the temporal bone and adjacent structures. Progression of the disease process can result in serious sequelae, including cranial nerve palsies and death. There is currently no formal published treatment guideline.

OBJECTIVE

This study aimed to integrate current evidence and data from our own retrospective case series in order to develop a guideline to optimise necrotising otitis externa patient management.

METHODS

A retrospective review of necrotising otitis externa cases within NHS Lothian, Scotland, between 2013 and 2018, was performed, along with a PubMed review.

RESULTS

Prevalent presenting signs, symptoms and patient demographic data were established. Furthermore, features of cases associated with adverse outcomes were defined. A key feature of the guideline is defining at-risk patients with initial intensive treatment. Investigations and outcomes are assessed and treatment adjusted appropriately.

CONCLUSION

This multi-departmental approach has facilitated the development of a succinct, systematic guideline for the management of necrotising otitis externa. Initial patient outcomes appear promising.

Synchronous Occurrence of Bilateral Malignant Otitis Externa: Report of a Rare Case

Malignant otitis externa (MOE) is a rare and potentially life-threatening disease of the ear and temporal bone. Bilateral simultaneous MOE is extremely rare. Due to bilaterally symmetrical facial nerve palsy, it can easily be missed at the initial presentation, causing delay in management. Here, we report a case of bilateral MOE managed aggressively with regular ear toileting, ear packing with a ribbon gauze soaked with topical antimicrobials, and long-term intravenous and oral antibiotics. The patient showed good improvement in pain control, facial nerve status, and ear findings.

An intact bony tympanic facial canal does not protect from secondary facial paresis in adult acute otitis media

OBJECTIVE

To investigate the prevalence of bony dehiscence in the tympanic facial canal in patients with acute otitis media with facial paresis compared to those without facial paresis.

METHOD

A retrospective case-control study was conducted on acute otitis media patients with facial paresis undergoing high-resolution temporal bone computed tomography.

RESULTS

Forty-eight patients were included (24 per group). Definitive determination of the presence of a bony dehiscence was possible in 44 out of 48 patients (91.7 per cent). Prevalence of bony dehiscence in acute otitis media patients with facial paresis was not different from that in acute otitis media patients without facial paresis (p = 0.21). Presence of a bony dehiscence was associated with a positive predictive value of 66.7 per cent in regard to development of facial paresis. However, an intact bony tympanic facial canal did not prevent facial paresis in 44.8 per cent of cases (95 per cent confidence interval = 34.6-55.6).

CONCLUSION

Prevalence of bony dehiscence in acute otitis media patients with facial paresis did not differ from that in acute otitis media patients without facial paresis. An intact tympanic bony facial canal does not protect from facial paresis development.

A large case series of temporal bone fractures at a UK major trauma centre with an evidence-based management protocol

OBJECTIVE

To review the management of temporal bone fractures at a major trauma centre and introduce an evidence-based protocol.

METHODS

A review of reports of head computed tomography performed for trauma from January 2012 to July 2018 was conducted. Recorded data fields included: mode of trauma, patient age, associated intracranial injury, mortality, temporal bone fracture pattern, symptoms and intervention.

RESULTS

Of 815 temporal bone fracture cases, records for 165 patients met the inclusion criteria; detailed analysis was performed on the records of these patients.

CONCLUSION

Temporal bone fractures represent high-energy trauma. Initial management focuses on stabilisation of the patient and treatment of associated intracranial injury. Acute ENT intervention is directed towards the management of facial palsy and cerebrospinal fluid leak, and often requires multidisciplinary team input. The role of nerve conduction assessment for immediate facial palsy is variable across the UK. The administration of high-dose steroids in patients with temporal bone fracture and intracranial injury is not advised. A robust evidence-based approach is introduced for the management of significant ENT complications associated with temporal bone fractures.

Condylar jugular diverticulum: A report of 3 cases

Jugular bulb diverticulum is an irregular extension of the jugular bulb into the temporal bone that may be symptomatic or asymptomatic. The jugular bulb has rarely been reported to extend into the occipital condyle; such extension is termed a condylar jugular diverticulum and is characterized as a defect in the occipital condyle contiguous with the jugular bulb. This report details 3 cases of condylar jugular diverticulum. Extension of the jugular bulb into the ipsilateral occipital condyle was noted as an incidental finding on cone-beam computed tomographic (CBCT) images of 3 patients. All 3 patients were asymptomatic, and this finding was unrelated to the initial area of interest. CBCT use is becoming ubiquitous in dentistry, as it allows 3-dimensional evaluation, unlike conventional radiography. Proper interpretation of the entire CBCT is essential, and recognition of the indicators of condylar jugular diverticulum may prevent misdiagnosis of this rare entity.

Relation between temporal bone pneumatisation and middle-ear barotrauma in aircrew members

OBJECTIVE

This study aimed to assess the potential role of pneumatisation of the mastoid and its communicating air cells in the development of middle-ear barotrauma in aircrew members.

METHODS

Seventy-nine aircrew members (158 ears) underwent temporal computed tomography. All were assessed before flying by clinical examination and audiology evaluation, followed by post-flight examination to detect barotrauma.

RESULTS

Aircrew members' ears were divided into 3 groups based on barotrauma and temporal bone pneumatisation: 33 ears with barotrauma and temporal bone pneumatisation of 71 cm3 or greater (group A); 12 ears with barotrauma and temporal bone pneumatisation of 11.2 cm3 or lower (group B); and 113 ears with no barotrauma (group C). Mean pneumatisation volumes were 91.05 cm3, 5.45 cm3 and 28.01 cm3 in groups A, B and C, respectively. A direct relationship was observed between volume of temporal bone pneumatisation of 71 cm3 or greater and barotrauma grade.

CONCLUSION

Pneumatisation volume of the mastoid and its communicating air cells that ranges from 11.3 cm3 to 70.4 cm3 serves as a reliable predictor of the avoidance of middle-ear barotrauma associated with flying in aircrew members who have normal resting middle-ear pressure and good Eustachian tube function.

Paediatric Bonebridge: bilateral simultaneous asymmetrical implantation

BACKGROUND

The Bonebridge is an active transcutaneous bone conduction implant recommended as a surgical option for adults and children (aged 5-18 years). Successful implantation of the Bonebridge is often restricted by an insufficient amount of temporal bone to house the transducer in the paediatric patient.

METHOD AND RESULTS

In this unique paediatric case, bilateral Bonebridge devices were implanted simultaneously in the right sinodural angle and the left middle cranial fossa.

CONCLUSION

The simultaneous implantation of bilateral Bonebridge devices was well tolerated in this paediatric patient, with significant improvement in her hearing. The middle cranial fossa is a viable option for housing the transducer.

Gradenigo's syndrome in a four-year-old patient: a rare diagnosis in the modern antibiotic era

OBJECTIVE

This study gives details of a rare case of petrous apicitis that presented as Gradenigo's syndrome and was managed surgically.

METHOD

This study presents a case report and review of the literature.

RESULTS

A four-year-old female was admitted for failure to thrive following recent sinusitis. Physical examination was positive for right sided facial pain, photophobia and right abducens nerve palsy. Subsequent magnetic resonance imaging revealed a 1.3 × 1.7 × 1.4 cm abscess encompassing the right Meckel's cave. A computed tomography scan showed petrous apicitis and otomastoiditis, confirming Gradenigo's syndrome. The patient was taken to the operating theatre for right intact canal wall mastoidectomy with myringotomy and tube placement. She was discharged on six weeks of ceftriaxone administered by a peripherally inserted central catheter line. At a two-week post-operative visit, she showed notable improvement in neuropathic symptoms.

CONCLUSION

This study presents a rare case of petrous apicitis managed surgically without the need for a craniotomy or transcochlear procedure.

The Bonebridge active bone conduction system: a fast and safe technique for a middle fossa approach

BACKGROUND

The transmastoid pre-sigmoid approach is always the preferred choice for implantation of the Bonebridge active bone conduction system in patients with a normal anatomy. When an anatomical variant exists or a previous surgery has been performed, a retrosigmoid approach or middle fossa approach can be performed.

METHODS

The preferred surgical technique for a middle fossa approach is described. A 14 mm drill head (Neuro Drill) was used to create the bed at the squamous portion of the temporal bone. Surgical time and complication rate were analysed.

RESULTS

The surgical time was shorter than 30 minutes in all cases, and only 14 seconds were needed to create a 14 mm bone bed. No complications were observed during the follow-up period (6-45 months).

CONCLUSION

Use of the Neuro Drill for the middle fossa approach is an easy technique. It significantly decreases the surgical time, without increasing the complication rate.

A dural arteriovenous fistula associated with an encephalocele presenting as otitis media with effusion

OBJECTIVE

This case report illustrates an unusual case of a dural arteriovenous fistula and an associated encephalocele presenting as otitis media with effusion.Case reportA 53-year-old man presented with right-sided hearing loss and aural fullness of 2 years' duration. Examination revealed ipsilateral post-auricular pulsatile tenderness. Computed tomography showed transcalvarial channels suggestive of dural arteriovenous fistula. Further magnetic resonance imaging demonstrated the presence of a temporal encephalocele herniating through the tegmen tympani defect, as well as the abnormal vascularity. Angiography confirmed a Cognard type I dural arteriovenous fistula, which is being managed conservatively. Surgical repair of the encephalocele was recommended but declined by the patient.

CONCLUSION

Dural arteriovenous fistula is an uncommon intracranial vascular malformation rarely seen by otolaryngologists, with pulsatile tinnitus being the usual presentation. To our knowledge, this is the first reported case of dural arteriovenous fistula presenting with conductive hearing loss and otalgia.

Temporomandibular joint synovial chondromatosis accompanying temporal bone proliferation: A case report

Synovial chondromatosis is a rare metaplastic disease affecting the joints, including the temporomandibular joint (TMJ). Since its symptoms are similar to those of temporomandibular disorders, a careful differential diagnosis is essential. A 50-year-old male patient was referred with the chief complaint of pain and radiopaque masses around the left TMJ on panoramic radiography. Clinically, pre-auricular swelling and resting pain was found, without limitation of mouth opening. On cone-beam computed tomographic images, multiple calcified nodules adjacent to the TMJ and bone proliferation with sclerosis at the articular fossa and eminence were found. T2-weighted magnetic resonance images showed multiple signal-void nodules with high signal effusion in the superior joint space and thickened cortical bone at the articular fossa and eminence. The calcified nodules were removed by surgical excision, but the hypertrophic articular fossa and eminence remained. A histopathological examination confirmed the diagnosis. The patient was followed up few months later without recurrence.

Clinical Characteristics of Temporal Bone Metastases

Objectives

The purposes of this study were to evaluate the clinical characteristics of temporal bone metastasis (TBM) and to determine whether the characteristics differed according to primary malignancy.

Methods

We retrospectively analyzed data on 20 patients diagnosed with TBM between January 2000 and January 2017. Demographics, the period from diagnosis of primary malignancy to TBM diagnosis, the period from TBM diagnosis to death, the type and staging of primary malignancy, otologic manifestations, and TBM sites were assessed. After the primary malignancies were divided into solid cancers and hematologic malignancies, each parameter was compared between the two groups.

Results

The most common primary malignancy with TBM was lung cancer (45%). The most common otologic symptoms and signs were facial palsy (30.5%) and hearing loss (30.5%). The temporal squama (23%) and the facial nerve (20%) were the most commonly involved. Most TBMs occurred late in the disease process after the primary malignancy first metastasized to other organs. Hematologic malignancies metastasized significantly more frequently to the external auditory canal and the middle ear/mastoid compared to solid cancers (P=0.001 and P=0.004, respectively).

Conclusion

If otologic manifestations such as facial palsy and hearing loss are presented in patients at advanced stages of malignancy, TBM of primary malignancy should be suspected. In addition, hematologic malignancies tend to metastasize to the external auditory canal and the middle ear cleft more commonly than solid cancers do.

Zygomatic Air Cell Defect - Magnetic Resonance Imaging of the Temporomandibular Joint Compared with Panoramic Radiographs

SUMMARY – The aim of the study was to analyze zygomatic air cell defect (ZACD) incidence using magnetic resonance imaging (MRI) and validity of panoramic radiograph as a comparative method of ZACD diagnostics. The connection between ZACD incidence, age, left/right temporomandibular joint (TMJ) and comorbidity with diagnosis of TMJ disorder was analyzed. Panoramic radiographs and MRIs of 140 TMJs of 70 consecutive patients with previously confirmed TMJ diagnosis were compared in the study. A grading system (4-point scale from ‘0’ for absence to ‘3’ for most extended pneumatization) was used to determine low signal on MRIs as pneumatization of temporal bone. ZACD was diagnosed in 22 joints of 15 patients (incidence, 20.4%), with seven patients having bilateral appearance. In the joints of nine patients, ZACD was identified as extensive according to the grading scale. The validity of ZACD findings on panoramic radiographs compared with MRI findings yielded 0.45 sensitivity and 0.98 specificity. There was no relation (p>0.05) between comorbidity of ZACD and TMJ disorder, either by age or side of the body. More prevalent ZACD in our MRI analysis than in other researches based on panoramic radiographs could be explained by the expected superimposed osseous structures in the area of articular eminence.

Prognostic Factors Affecting Surgical Outcomes in Squamous Cell Carcinoma of External Auditory Canal

Objectives

Carcinomas of the external auditory canal (EAC) are rare, and management remains challenging. Previous studies seeking prognostic factors for EAC cancers included cancers other than carcinomas. In this study, we analyzed the treatment outcomes of, prognostic factors for, and survival rates associated with specifically squamous cell carcinoma (SCC) of the EAC.

Methods

A retrospective review of 26 consecutive patients diagnosed with SCCs of the EAC in a 10-year period was performed in terms of clinical presentation, stage, choice of surgical procedure, and adjunct therapy. Overall survival (OS) and recurrence-free survival (RFS) were calculated and univariate analysis of prognostic factors was performed.

Results

The median age of the 26 patients with SCCs of the EAC was 63 years (range, 40 to 72 years), and 16 males and 10 females were included. According to the modified University of Pittsburgh staging system, the T stages were T1 in 11, T2 in six, T3 in four, and T4 in five cases. The surgical procedures employed were wide excision in three cases, lateral temporal bone resection (LTBR) in 17, and extended LTBR in four, and subtotal temporal bone resection in two. Two patients underwent neoadjuvant chemotherapy, and two underwent adjuvant chemotherapy. One patient received preoperative radiation therapy, and eleven received postoperative radiation therapy. Of the possibly prognostic factors examined, advanced preoperative T stage and advanced overall stage were significant predictors of RFS, but not of OS.

Conclusion

The advanced T stage and overall stage were associated with decreased survival after surgical treatment in patients with SCC of the EAC, highlighting the importance of clinical vigilance and early detection.

Concurrent Mastoid Cellulitis and Langerhans Cells Histiocytosis: A Challenging Diagnosis

Langerhans cell histiocytosis (LCH) is a rare proliferative disorder, which commonly arises in the bone and may involve other systems. To date, the diagnosis of temporal bone LCH remains a challenge as it may masquerade as a common ear infection. We report a case of a child who presented to us with persistent bilateral ear discharge for four months and was not responding to treatment. Her condition subsequently worsened, with clinical features and radiological findings suggestive of mastoid cellulitis. Nevertheless, further histopathology study revealed LCH.

Efficacy of Tympanoplasty Without Mastoidectomy for Treating Chronic Otitis Media in Patients With Mastoid Cavity Opacification in Temporal Bone Computed Tomography Findings

Objectives

Combined mastoidectomy is generally preferred to tympanoplasty alone when treating patients with chronic otitis media (COM), particularly when temporal bone computed tomography (TBCT) shows that the mastoid cavity contains opacification of soft tissue density. However, in cases with Eustachian tube dysfunction, a mastoid cavity volume may be a burden to its function. We hypothesized that tympanoplasty alone might be better than tympanoplasty combined with mastoidectomy because soft tissue in the mastoid cavity is a sequel to a protective physiological response. Thus, we explored the efficacy of tympanoplasty without mastoidectomy in COM patients exhibiting mastoid air cell opacification on TBCT.

Methods

Between 2010 and 2014, a total of 33 patients, diagnosed with COM and with evidence of mastoid cavity opacification on TBCT, underwent tympanoplasty without mastoidectomy. All ears had been dry for ≥3 months before surgery. All procedures were performed by the same surgeon. We retrospectively analyzed the preoperative otoscopic findings, pre- and postoperative pure tone averages (PTAs; the mean of the values at 0.5, 1, 2, and 4 kHz), surgical procedures, and complications or recurrence.

Results

Of the 33 patients, 28 (84.8%) exhibited hearing improvement after surgery. The mean pre- and postoperative PTAs were 46.9±21.2 dB and 29.4±17.0 dB, respectively (P<0.001). The air-bone gap decreased from 25.7±10.7 dB to 10.3±8.7 dB (P<0.001). Thirty-two patients (97.0%) did not develop any COM recurrence or cholesteatoma; one patient developed attic retraction of the tympanic membrane. Other minor complications were transient otorrhea caused by myringitis (two cases) and a pinpoint perforation (one case).

Conclusion

Tympanoplasty alone, i.e., without mastoidectomy, may adequately control COM, if it shows dry-up status for at least 3 months even though mastoid cavity opacification is detected in TBCT.

Presentation of automated procedural guidance in surgical simulation: results of two randomised controlled trials

OBJECTIVE

To investigate the effectiveness and usability of automated procedural guidance during virtual temporal bone surgery.

METHODS

Two randomised controlled trials were performed to evaluate the effectiveness, for medical students, of two presentation modalities of automated real-time procedural guidance in virtual reality simulation: full and step-by-step visual presentation of drillable areas. Presentation modality effectiveness was determined through a comparison of participants' dissection quality, evaluated by a blinded otologist, using a validated assessment scale.

RESULTS

While the provision of automated guidance on procedure improved performance (full presentation, p = 0.03; step-by-step presentation, p < 0.001), usage of the two different presentation modalities was vastly different (full presentation, 3.73 per cent; step-by-step presentation, 60.40 per cent).

CONCLUSION

Automated procedural guidance in virtual temporal bone surgery is effective in improving trainee performance. Step-by-step presentation of procedural guidance was engaging, and therefore more likely to be used by the participants.

Gorham-Stout disease of the temporal bone involving the temporomandibular joint

BACKGROUND

Gorham-Stout disease of the skull is a very rare entity. It presents with gradual bone resorption, and proliferation of lymphoid and vascular channels within the bony matrix. This is often a diagnosis of exclusion confirmed with serial imaging and based on radiological evidence.

CASE REPORT

A case of Gorham-Stout disease of the temporal bone involving the temporomandibular joint, and presenting with sensorineural hearing loss and recurrent temporomandibular joint dislocation, is reported. The findings are presented and the literature on this condition is reviewed.

CONCLUSION

ENT and maxillofacial surgeons should be aware of this extremely rare cause of temporomandibular joint dislocation and ear symptoms. Imaging comprising computed tomography and magnetic resonance imaging is crucial to achieving a diagnosis, which may only become evident after repeated imaging follow up. Symptomatic treatment is advised, with the option of anti-osteoclastic medication and radiotherapy indicated for advanced cases. Surgery is only recommended for complications including involvement of neurovascular structures.

A histopathological connection between a fatal endolymphatic sac tumour and von Hippel-Lindau disease from 1960

OBJECTIVE

To highlight a case from 1960 connecting endolymphatic sac tumour and von Hippel-Lindau disease.

CASE REPORT

In 1960, a 24-year-old woman presented with unilateral hearing loss, pulsatile tinnitus and a mass visible on otoscopy. The patient underwent surgical biopsy, which was complicated by haemorrhage, and ultimately resulted in death. At autopsy, a destructive temporal bone neoplasm with cystic and papillary architecture was observed that had eroded into the otic capsule. Intra-abdominal lesions consistent with von Hippel-Lindau disease were also observed, and the surgeon postulated a connection between endolymphatic sac tumour and von Hippel-Lindau disease.

METHOD

A review of the literature was carried out using PubMed.

CONCLUSION

Endolymphatic sac tumours are rare neoplasms of the temporal bone that can occur sporadically or as part of von Hippel-Lindau disease. The connection between endolymphatic sac tumour and von Hippel-Lindau disease was first proposed in 1988 and formalised in 1997. We believe that this case represents the first documented connection between endolymphatic sac tumour and von Hippel-Lindau disease.

Chronically Discharging Ears: Evalution with High Resolution Computed Tomography

Chronic suppurative otitis media (CSOM) refers to the middle ear inflammation which is clinically characterized by the discharging ear, hearing deficit, fever and otalgia. Although a clinical diagnosis, imaging is imperative to rule out associated complications which apart from causing hearing deficit, may prove fatal at times.

Both high resolution computed tomography (HRCT) and MRI are helpful in evaluating middle ear pathologies, usage being indication specific. Due to its excellent spatial resolution, HRCT is invaluable in assessment of chronically discharging ears, especially to look for bone erosion and the integrity of the ossicles. Due to its better spatial resolution, HRCT is preferred in suspected intra temporal complications whereas MRI is more useful in evaluating intracranial extension.

Effects of a sensory branch to the posterior external ear canal: coughing, pain, Ramsay Hunt's syndrome and Hitselberger's sign

BACKGROUND

A distinct nerve innervating the external auditory canal can often be identified in close relation to the facial nerve when gradually thinning the posterior canal wall. This nerve has been attributed to coughing during cerumen removal, neuralgic pain, Hitselberger's sign and vesicular eruptions described in Ramsay Hunt's syndrome. This study aimed to demonstrate the origin and clinical impact of this nerve.

METHODS AND RESULTS

In patients with intractable otalgia or severe coughing whilst inserting a hearing aid, who responded temporarily to local anaesthesia, the symptoms could be resolved by sectioning a sensory branch to the posterior canal. In a temporal bone specimen, it was revealed that this nerve is predominantly a continuation of Arnold's nerve, also receiving fibres from the glossopharyngeal nerve and facial nerve. Histologically, the communicating branch from the facial nerve was confirmed.

CONCLUSION

Surgeons should be aware of the posterior auricular sensory branch and its clinical implications.

External auditory canal meningioma: imaging features in a series of three cases

BACKGROUND

Direct extension of an intracranial meningioma to involve the temporal bone is rare. Recognised sites of origin and routes of access to the middle ear and labyrinthine apparatus have been described. Direct spread through the temporal bone to primarily involve the external auditory canal has not been widely reported in the literature.

CASE REPORTS

This paper discusses clinical and radiological findings in three cases of temporal bone meningioma presenting as masses within the external auditory canal.

CONCLUSION

Diagnosing temporal meningioma can be challenging because of its rarity and the often non-specific clinical and histological findings. It is important for both the surgeon and radiologist to be aware of the diagnosis and its related imaging findings in order to facilitate a timely diagnosis.

Effects of anatomical variation on trainee performance in a virtual reality temporal bone surgery simulator

OBJECTIVE

To investigate the importance of anatomical variation in acquiring skills in virtual reality cochlear implant surgery.

METHODS

Eleven otolaryngology residents participated in this study. They were randomly allocated to practice cochlear implant surgery on the same specimen or on different specimens for four weeks. They were then tested on two new specimens, one standard and one challenging. Videos of their performance were de-identified and reviewed independently, by two blinded consultant otolaryngologists, using a validated assessment scale. The scores were compared between groups.

RESULTS

On the standard specimen, the round window preparation score was 2.7 ± 0.4 for the experimental group and 1.7 ± 0.6 for the control group (p = 0.01). On the challenging specimen, instrument handling and facial nerve preservation scores of the experimental group were 3.0 ± 0.4 and 3.5 ± 0.7 respectively, while the control group received scores of 2.1 ± 0.8 and 2.4 ± 0.9 respectively (p < 0.05).

CONCLUSION

Training on temporal bones with differing anatomies is beneficial in the development of expertise.

Pathogenesis and Bone Resorption in Acquired Cholesteatoma: Current Knowledge and Future Prospectives

Cholesteatoma is a cystic non tumorous lesion of the temporal bone that has the ability to destroy nearby structures by its power to cause bone resorption and as a result, fatal complications prevail. We aimed to conduct a comprehensive review for pathogenesis of acquired cholesteatoma, bone resorption mechanisms, and offer a future vision of this serious disease. We have reviewed different theories for pathogenesis of acquired cholesteatoma including the most relevant and updated ones with special emphasis on the mechanisms of bone resorption through Medline/PubMed research using the keywords 'aetiopathogenesis, bone resorption, acquired cholesteatoma, temporal bone, and cytokines.' In order to strengthen our study, we searched the reference lists of identified reviews. Cholesteatoma is a subject of debate among otolaryngologists since it was prescribed firstly. Over many decades, several theories were postulated for aetiopathogenesis of cholesteatoma with a tendency to follow more than one theory to explain the proper nature of that disease. Until now, the mechanism of bone resorption has yet to be more clarified. In the last century, a leap has occurred in the field of biomolecular cholesteatoma research which improved our knowledge about its pathophysiology and bone destructive mechanism. However, surgery is still the only available treatment. We conclude that discovery of new therapeutic choices for cholesteatoma other than surgery by the use of anti-growth, anti-proliferative, apoptotic agents as well as medications that antagonize osteoclastogenesis should be the main concern in the future clinical and experimental research work. Also, searching for predictors of the aggressiveness of cholesteatoma can affect the timing of intervention and prevent occurrence of complications.

Audiologic Patterns of Otic Capsule Preserving Temporal Bone Fracture: Effects of the Affected Subsites

Objectives.

This study was aimed to assess the relationship between the type of temporal bone area involved and conductive hearing loss.

Methods.

We enrolled 97 patients who visited the otolaryngology clinics of Seoul National University Hospital or Boramae Medical Center, Seoul Metropolitan Government-Seoul National University with temporal bone fracture between January 2004 and January 2014. Audiometric parameters, including initial and improved air-bone (AB) conduction gap values, were reviewed in accordance with the temporal bone computed tomography (external auditory canal [EAC], middle ear [ME], mastoid [M], and ossicle [O]).

Results.

Patients with ossicular chain involvement exhibited a larger AB gap compared to those with no ossicular chain involvement at 250, 1,000, 2,000, and 4,000 Hz. Among the groups without ossicular chain involvement, the initial AB gap was largest in patients with EAC+ME+M involvement, followed by the ME+M and M-only involvement groups. The greatest improvement in the AB gap was observed in the EAC+ME+M group followed by the ME+M and M-only groups, irrespective of ossicular chain involvement. Improvements in AB gap values were smallest at 2,000 Hz.

Conclusion.

Conductive hearing loss pattern differed according to the temporal bone area involved. Therefore, areas such as the hematoma and hemotympanum, as well as the fracture line of the temporal bone area, must be evaluated to predict audiologic patterns with otic capsule preserving temporal bone fracture.

Incidental occurrence of an unusually large mastoid foramen on cone-beam computed tomography and review of the literature

The incidental finding of an enlarged mastoid foramen on the right posterior mastoid region of temporal bone is reported, together with a discussion of its clinical significance. A 67-year-old female underwent the pre-implant assessment of a maxillary left edentulous region. A cone-beam computed tomographic (CBCT) image was acquired and referred for consultation. Axial CBCT slices revealed a unilateral, well-defined, noncorticated, low-attenuation, transosseous defect posterior to the mastoid air cells in the right temporal bone. The borders of the osseous defect were smooth and continuous. No other radiographic signs suggestive of erosion or sclerosis were noted in the vicinity. The density within the defect was homogenous and consistent with a foramen and/or soft tissue. The patient's history and physical examination revealed no significant medical issues, and she was referred to a neuroradiologist for a second opinion. The diagnosis of an enlarged mastoid foramen was made and the patient was reassured.

Normal Mastoid Air Cell System Geometry: Has Surface Area Been Overestimated?

OBJECTIVES

The aim of this study was to emphasize the necessity of a standard in segmentation threshold and algorithm for measuring volume and surface area of mastoid air cell system (MACS).

METHODS

First, we obtained axial computed tomography scans of 54 normal temporal bones from 27 subjects. Then, we manipulated Hounsfield units (HU) image data in DICOM (digital imaging and communications in medicine) files directly using our program. The volume and surface area of MACS were computed and compared at segmentation thresholds (HU) from -700 to 0 at intervals of 50 using 2 algorithms; square pixel based (SP) algorithm and marching square (MS) algorithm.

RESULTS

No significant difference was found between the volumes computed by SP and MS algorithms at each segmentation threshold. The surface area computed by SP algorithm, however, was significantly larger than that by MS algorithm. We could minimize this significant difference through a modification of the SP algorithm. As the lower HU threshold value was set, the smaller volume was measured. The surface area showed a plateau at a threshold of approximately -200 HU. The segmentation threshold had greater influence on the measured volume of MACS than the algorithm did.

CONCLUSION

A standard method for measuring volume and surface area of MACS is thought to be necessary. We suggest that the MS algorithm and -200 HU of the threshold could be a standard in the measurement of volume and surface area of MACS.

Bilateral Facial Paralysis Caused by Temporal Bone Fracture: A Case Report

INTRODUCTION

Although bilateral facial nerve palsy is a rare condition, its etiology is more detectable than the unilateral type. A temporal bone fracture is one cause of bilateral facial nerve palsy, contributing in 3% of the cases.

CASE PRESENTATION

Here, we report the case of a 35-year-old man complaining of bilateral incomplete eye closure, two weeks after a closed head injury caused by a motor vehicle accident.

CONCLUSIONS

The high resolution computed tomography findings revealed a bilateral temporal bone fracture line, which extended to the fallopian canal. With regard to treatment, near complete recovery was obvious after two weeks of treatment with oral corticosteroids. Overall, bilateral facial palsy is hard to diagnose; therefore, clinical suspicion and the early detection of facial nerve injuries is necessary for good nerve recovery in temporal bone fractures.

Anatomical Factors Influencing Pneumatization of the Petrous Apex

Objectives

Aim of the present study was to define the relationship between petrous apex pneumatization and the nearby major anatomical landmarks using temporal bone computed tomography (CT) images.

Methods

This retrospective, Institutional Review Board-approved study analyzed CT images of 84 patients that showed normal findings bilaterally. Pneumatization of the petrous apex was classified using two methods. Eight parameters were as follows: angle between the posterior cranial fossa and internal auditory canal, Morimitsu classification of anterior epitympanic space, distance between the carotid canal and jugular bulb, distance between the cochlear modiolus and carotid canal, distance between the tympanic segment and jugular bulb, high jugular bulb, distance between the vertical segment and jugular bulb, and distance between the lateral semicircular canals and middle cranial fossa.

Results

There was a significant difference in Morimitsu classification of the anterior epitympanic space between the two classification methods. Poorly pneumatic upper petrous apices were distributed uniformly in three types of Morimitsu classification, but more pneumatic upper petrous apices were found more often in anterior type. Lower petrous apex was well pneumatized regardless of the types of anterior epitympanic space, but the largest amount of pneumatization was found more frequently in the anterior type of anterior epitympanic space.

Conclusion

This study showed that there was no reliable anatomic marker to estimate petrous apex pneumatization and suggests that the pneumatization of the petrous apex may be an independent process from other part of the temporal bone, and may not be influenced by the nearby major anatomical structures in the temporal bone. In this study, the anterior type of anterior epitympanic space was found to be closely related to more well-pneumatized petrous apices, which implies that the anterior saccule of the saccus medius may be the main factor influencing pneumatization of the petrous apex.

Peak and ceiling effects in final-product analysis of mastoidectomy performance

BACKGROUND

Virtual reality surgical simulation of mastoidectomy is a promising training tool for novices. Final-product analysis for assessing novice mastoidectomy performance could be limited by a peak or ceiling effect. These may be countered by simulator-integrated tutoring.

METHODS

Twenty-two participants completed a single session of self-directed practice of the mastoidectomy procedure in a virtual reality simulator. Participants were randomised for additional simulator-integrated tutoring. Performances were assessed at 10-minute intervals using final-product analysis.

RESULTS

In all, 45.5 per cent of participants peaked before the 60-minute time limit. None of the participants achieved the maximum score, suggesting a ceiling effect. The tutored group performed better than the non-tutored group but tutoring did not eliminate the peak or ceiling effects.

CONCLUSION

Timing and adequate instruction is important when using final-product analysis to assess novice mastoidectomy performance. Improved real-time feedback and tutoring could address the limitations of final product based assessment.

Anatomical variations of the temporal bone on high-resolution computed tomography imaging: how common are they?

OBJECTIVES

This study aimed to evaluate the prevalence of normal variations of temporal bone anatomy on high-resolution computed tomography imaging and report their clinical importance.

METHODS

A retrospective review was conducted of high-resolution temporal bone computed tomography imaging performed at NHS Greater Glasgow and Clyde over an eight-year period. The presence of five variants was determined. These variants were: a high dehiscent jugular bulb, an anteriorly located sigmoid sinus, a deep sinus tympani, an enlarged cochlear aqueduct and a large internal auditory meatus.

RESULTS

A total of 339 temporal bones were examined. The incidences of a high dehiscent jugular bulb, anteriorly located sigmoid sinus, deep sinus tympani, enlarged cochlear aqueduct and an enlarged internal auditory meatus were 2.76 per cent, 2.94 per cent, 5.01 per cent, 0.58 per cent and 1.76 per cent respectively.

CONCLUSION

Anatomical variations of the temporal bone are not uncommon and it is important for the investigating otologist to be aware of such variations prior to undertaking surgery.

Face and content validation of a novel three-dimensional printed temporal bone for surgical skills development

OBJECTIVE

To assess the face and content validity of a novel synthetic, three-dimensional printed temporal bone for surgical skills development and training.

METHODS

A synthetic temporal bone was printed using composite materials and three-dimensional printing technology. Surgical trainees were asked to complete three structured temporal bone dissection exercises. Attitudes and impressions were then assessed using a semi-structured questionnaire. Previous cadaver and real operating experiences were used as a reference.

RESULTS

Trainees' experiences of the synthetic temporal bone were analysed in terms of four domains: anatomical realism, usefulness as a training tool, task-based usefulness and overall reactions. Responses across all domains indicated a high degree of acceptance, suggesting that the three-dimensional printed temporal bone was a useful tool in skills development.

CONCLUSION

A sophisticated three-dimensional printed temporal bone that demonstrates face and content validity was developed. The efficiency in cost savings coupled with low associated biohazards make it likely that the printed temporal bone will be incorporated into traditional temporal bone skills development programmes in the near future.

Pneumatized Articular Eminence and Assessment of Its Prevalence and Features on Panoramic Radiographs

OBJECTIVES

Pneumatized articular eminence or tubercle (PAT) is an air cell cavity in the zygomatic process of the temporal bone. Pneumatization of articular eminence may be seen incidentally on panoramic radiographs (PRs) as a unilocular or multilocular radiolucent defect. The aim of this study was to assess the prevalence and the pattern of PAT on PR in an Iranian population.

MATERIALS AND METHODS

A total of 3,098 PRs belonging to 1,735 females and 1,363 males were retrospectively investigated for the presence and radiographic features of PAT. All PRs were taken for routine dental examination. Chi-square test, univariate odds ratio (OR) and corresponding 95% confidence interval (95% CI) and binary logistic regression were used for statistical analysis.

RESULTS

Overall, PAT was found in 2.1 % of cases including 41 females and 23 males (with a mean age of 33.23±12.43 and 35.64±13.24 years, respectively, range 19-69 years). There were 40 unilateral and 24 bilateral cases (total: 88 PATs) including 49 unilocular and 39 multilocular cases. There was no significant difference in PAT between males and females or different age groups (P>0.05 and all CIs included 1.00). Binary logistic regression indicated that there was no relationship between the presence of PAT and age or sex.

CONCLUSION

Knowledge about this anatomical variation is helpful for clinicians who are planning to perform temporomandibular joint surgery. They should assess the radiographic imaging thoroughly before the surgery. It can also provide valuable information to understand the differential diagnosis of pathological entities in this region.

Temporal Bone Measurements; A Comparison Between Rendered Spiral CT and Surgery

Background:

Accurate radiological assessment of the anatomical features of the temporal bone is crucial to prevent damage to vital elements in this area during surgery. Knowing the approximate location of specific temporal bone related landmarks in advance is very important for planning surgery.

Objectives:

This study compared findings from computed tomography images with those observed directly during ear surgery.

Patients and Methods:

Patients with various pathologies of the ear who needed surgery were referred to an imaging center for a spiral CT scan of the temporal bone. The following parameters were measured by a radiologist and also later recorded by the surgeon during surgery: 1) The distance between the postero-superior border of the outer ear canal and the sigmoid sinus; 2) The distance between the dome of the lateral semicircular canal and the mastoid cortex; and 3) The distance between the external surface of the incus and the mastoid cortex.

Results:

Twenty cases were included. In the three measurements performed in this study, only the first parameter (distance between the canal and the sigmoid sinus) was significantly different between the direct measurement made during surgery and that obtained from CT scans. There was no significant difference in the measurements of the distance between the dome of the lateral semicircular canal and the bone cortex, and the distance between the external surface of the incus and the surface of the bone cortex.

Conclusions:

Our study shows in terms of figures that measurements of features of the temporal bone made from spiral CT scan images and those directly obtained during surgery are similar to an adequate extent.

Osteoid osteoma presenting as a painful solitary skull lesion: a case report

INTRODUCTION

Osteomas are asymptomatic and rare slow growing bony tumors in temporal bone, and should be taken into account in differential diagnosis of the osteolytic solitary skull lesions. Sometimes is associated with pain and functional loss. Only a few cases have been reported.

CASE REPORT

We describe a case of an osteoid osteoma of the temporal bone (mastoid) in a 31-year-old woman presenting as painful solitary tumor of calvarium and its management. The resection of whole bony tumor was performed using the retroauricular approach. Pathologic evaluation revealed the osteoid osteoma.

CONCLUSION

Although osteoid osteoma of the temporal bone is rare, it should be taken into account in differential diagnosis of the osteolytic skull lesions. Treatment is indicated for symptomatic osteomas or cosmetic reasons.

Prevalence and characteristics of pneumatized articular tubercle: First large series in Iranian people

Purpose

This study was performed to determine the prevalence and characteristics of pneumatized articular tubercle or eminence among a defined group of Iranian people.

Materials and Methods

Digital panoramic radiographs of 1694 patients in the Department of Oral and Maxillofacial Radiology, Hamadan Dental School, Iran were evaluated retrospectively to detect the above lesion. Finally, 1563 radiographs were selected according to inclusion criteria. Then, a review was done of 10 large case series found using a MEDLINE search of the literature. Chi-squared test was used to analyze the differences in variables such as age, gender, laterality, and locularity in our case series.

Results

The average age of our samples was 32.6±7.63 years. Pneumatized articular tubercle was found in 98 cases, representing a prevalence of 6.2% with a mean age of 22.8±7.9 and a range of 8 to 60 years. Sixty-four (65.3%) pneumatized articular tubercles were unilateral, with 30 lesions on the right and 34 on the left side. Bilateral lesions were found in 34 (34.7%) patients. 52 (53.06%) of the pneumatized articular tubercles were of the unilocular type and 46 (46.94%) were multilocular. The results showed no statistically significant differences regarding age (p=0.454), gender (p=0.634), laterality (p=0.252), or locularity (p=0.807) among the samples.

Conclusion

Among ten large case series from other countries, the prevalence of pneumatized articular tubercle (6.2%) in Iranian patients was higher than that of all eight of the case series that used the same detection method as the present study of panoramic radiography.

Morphometric analysis of the internal auditory canal by computed tomography imaging

Background

Many clinical and experimental studies have been done to analyze the anatomical and functional aspects of the internal auditory canal (IAC) in human beings since there are great inter-individual variability and structural variations that may occur regarding the other adjacent structures.

Objectives

The purpose of this study was to characterize the morphology of the internal auditory canal (IAC) during development using high resolution computed tomography (CT) and to analyze its dimensions, which will be determined by measuring the nearby areas and structures using a system of digital image processing.

Patients and Methods

CT images of the IAC of 110 normal subjects aged 1 to 92 years (mean age, 46.5 years) of both genders were reviewed to determine the shape, area, opening width (OW), longitudinal length (LL), vertical diameter (VD) and distance from the vestibular aqueduct.

Results

The shapes observed in children and adults were funnel-shaped (74% and 58.3%, respectively), cylindrical (22% and 30.9%, respectively) and bud-shaped (4% and 10.8%, respectively). The measurements by CT in children were: area= 50.30 mm², OW = 7.53 mm, length = 11.17 mm, VD = 4.82 mm and the distance between the IAC and the vestibular aqueduct (VA) = 12.63 mm. In adults, the measurements were: area = 44.64 mm², OW = 7.10 mm, length = 9.84 mm, VD = 4.47 mm and the distance between IAC and VA = 11.17 mm.

Conclusions

CT images showed that the IAC has different shapes and when the measurements obtained for children were compared with those of adults, the parameters that presented statistically significant differences in either gender were length and diameter.