Temporal Bone Fractures: A Review for the Oral and Maxillofacial Surgeon

Management of Greenstick Fracture at the Root of Adult Zygomatic Arch

Greenstick fractures mostly occur in children and rarely in adults. In adult zygomaticomaxillary complex fractures, the greenstick fracture at the root of the zygomatic arch is occasionally encountered. This makes it difficult to move the fracture segment. Therefore, achieving anatomic reduction is very difficult. Our preoperative 3D repaired model shows that if only the maxilla and zygomatic bones are restored, the patient's face will still have depression and protrusion. The greenstick fracture segment at the root of the zygomatic arch needs to undergo osteotomy to achieve anatomic reduction and restore facial symmetry. The patient's facial appearance was restored after the surgery. The postoperative computed tomography scan showed good alignment of the fracture. The authors believe that a fracture at the root of the zygomatic arch can serve as an indication for open reduction and fixation.

Evaluation and Outcomes of Hearing Loss in Temporal Bone Fractures: A Prospective Study

Background Fractures of the skull base occur in 3-30% of head injury presentations to the emergency department. Overall, 9-40% of the cases have temporal bone fractures (TBFs). This fracture may disrupt the intervening structures causing edema, hematoma, bleeding, hearing loss, dizziness, cerebrospinal fluid otorrhea, and facial nerve paralysis. This study aims to evaluate the type of TBF, its correlation with hearing loss, and the outcomes of hearing loss. Methodology A prospective observational study was done among 50 patients who presented to the emergency department following trauma with clinical features and CT of the temporal bone suggestive of TBF. A complete evaluation of the patients was done, and patients were managed as per the departmental protocol. The patients were followed up for six months and monitored for otological symptoms. Periodic assessment of hearing loss by pure tone audiometry (PTA) was performed at the end of one week, one month, and six months. Results The most common type of fracture in our study was longitudinal TBF (72%), followed by transverse TBF (20%) and mixed TBF (8%). According to the newer classification, otic capsule-sparing fracture was more common than otic capsule-violating fracture. Most patients presented with conductive hearing loss (60%) following the TBF. On follow-up, there was a statistically significant improvement in hearing loss at the end of six months. Conclusions Our study found that in most cases hearing loss improved over time. Patients with conductive hearing loss showed maximum improvement in comparison to patients with sensorineural and mixed hearing loss.

Rare Complication of Orthognathic Surgery: Intrusion of Mandibular Condyle into the Middle Cranial Fossa

Dislocation of mandibular condyle into the middle cranial fossa is rare but diagnosis and treatment timely is very important due to significant complications. In this paper, we present a very rare case of asymptomatic intrusion of the mandibular condyle into the middle cranial fossa after orthognathic surgery in a 23 year old man from Iran.

Traumatic dislocation of middle ear ossicles: A new computed tomography classification predicting hearing outcome

Objectives

To assess the feasibility of radiologic measurements and find out whether hearing outcome could be predicted based on computer tomography (CT) scan evaluation in patients with temporal bone fractures and suspected ossicular joint dislocation.

Methods

We assessed 4002 temporal bone CT scans and identified 34 patients with reported ossicular joint dislocation due to trauma. We excluded those with no proven traumatic ossicular dislocation in CT scan and patients with bilateral temporal bone fractures. We measured four parameters such as malleus-incus axis distance, malleus-incus angle at midpoints, malleus- incus axis angle and ossicular joint space. The contralateral healthy side served as its own control. Hearing outcome 1–3 months after the index visit was analyzed. We assessed diagnostic accuracy and performed a logistic regression using radiologic measurement parameters for outcome prediction of conductive hearing loss (defined as >20dB air-bone gap).

Results

We found excellent inter-rater agreement on the measurement of axis deviation between incus and malleus in CT scans (interclass correlation coefficient 0.81). The larger the deviation of incus and malleus axis, the higher probability of poor hearing outcome (odds ratio (OR) 2.67 per 0.1mm, p = .006). A cut-off value for the axis deviation of 0.25mm showed a sensitivity of 0.778 and a specificity of 0.94 (p < .001) for discrimination between poor and good hearing outcome in terms of conductive hearing loss.

Conclusion

Adequate assessment of high resolution CT scans of temporal bone in which ossicular chain dislocation had occurred after trauma was feasible. Axis deviations of the incus and the malleus were strongly predictive for poor hearing outcome in terms of air conduction 1–3 months after trauma. We propose a 3-level classification system for hearing outcome prediction based on radiologic measures.

Hearing and Mortality Outcomes following Temporal Bone Fractures

The aim of this article is to determine hearing and mortality outcomes following temporal bone fractures. Retrospective chart review was performed of 152 patients diagnosed with a temporal bone fracture presenting to the emergency room at a tertiary care referral center over a 10-year period. Utilizing Patients' previously obtained temporal bone computed tomographic scans and audiograms, fractures were classified based on several classification schemes. Correlations between fracture patterns, mortality, and hearing outcomes were analyzed using χ² tests. Ossicular chain disruption was seen in 11.8% of patients, and otic capsule violation was seen in 5.9%; 22.7% of patients presented for audiologic follow-up. Seventeen patients with conductive hearing loss had air-bone gaps of 26 ± 7.5 dB (500 Hz), 27 ± 6.8 dB (1,000 Hz), 18 ± 6.2 dB (2,000 Hz), and 32 ± 7.7 dB (4,000 Hz). Two cases of profound sensorineural hearing loss were associated with otic capsule violation. No fracture classification scheme was predictive of hearing loss, although longitudinal fractures were statistically associated with ossicular chain disruption ( p  < 0.01). Temporal bone fractures in patients older than 60 years carried a relative risk of death of 3.15 compared with those younger than 60 years. The average magnitude of conductive hearing loss resulting from temporal bone fracture ranged from 18 to 32 dB in this cohort. Classification of fracture type was not predictive of hearing loss, despite the statistical association between ossicular chain disruption and longitudinal fractures. This finding may be due to the low follow-up rates of this patient population. Physicians should make a concerted effort to ensure that audiological monitoring is executed to prevent and manage long-term hearing impairment.

A Case of Glenoid Fossa Fracture, Progressive Ankylosis, Total Joint Reconstruction with Alloplastic Prosthesis to Normalized Function Including Evaluation with F18-PET/CT-a Four Year Follow-up

Temporomandibular joint replacement (TJR) with alloplastic prosthesis has shown promising long-term results in end stage joint disorders. We present a case of young woman with painful ankylosis that where reconstructed with TJR, due to a complex mandibular fracture with dislocation of the left condyle into the middle cranial fossa two years earlier. At the age of 18 the subject underwent a total joint replacement with custom-made alloplastic TMJ prosthesis. To determine the bone response and remodeling activity around the prosthesis, a F18 PET/CT-scan was used. No sign of increased remodeling or pathology were seen in the imaging after the reconstruction. Four years postoperatively the subject reports no pain and excellent jaw function.

[Trauma of the temporal bone]

Temporal bone fractures are mostly due to high-energy head trauma with high rates of concurrent intracranial and cervical spine injuries and belong to the wider spectrum of lateral skull base trauma. Given that the temporal bone represents the most complex bone structure in the human body, containing a multitude of vital neurovascular structures, variable clinical presentations may arise from such fractures, ranging from asymptomatic courses to serious consequences, such as conductive and/or sensorineural hearing loss, vascular and/or cranial nerve injury as well as cerebrospinal fluid leakage. The present paper presents typical clinical sequelae and provides a detailed illustration of characteristic imaging findings related to temporal bone injury. Last but not least, in the final section of the manuscript the focus is placed on distinct anatomic structures which may mimic fracture lines and, thus, entail a high potential for misclassification as temporal bone fractures.

Control of cerebrospinal fluid otorrhea via C-arm-guided reduction of the zygomatic arch as a part of the temporal bone: interdisciplinary approach to an unusual craniomaxillofacial fracture

Maxillofacial fractures are often associated with blunt head injuries, of which skull base trauma is a common component. However, most oral and maxillofacial surgeons do not provide definitive management of temporal bone fractures involving the skull base and their sequelae. Persistent cerebrospinal fluid (CSF) leakage that is refractory to conservative measures usually requires surgical closure to decrease the risk of meningitis. In general, reduction of the displaced fragment of the skull base in temporal bone fractures is not considered a priority. We describe an unusual case of craniomaxillofacial injury exhibiting CSF otorrhea because of a temporal bone fracture with a fragment that included the zygomatic arch. The persistent traumatic leakage was stopped after C-arm-guided reduction of the depressed zygomatic arch. This technique facilitated minimal and only necessary manipulation, without overcorrection, thereby avoiding additional damage to the surrounding tissues. The present case illustrates the definitive contribution of therapeutic measures based on maxillofacial surgery as part of an interdisciplinary approach to the management of the complications of severe head injuries; more invasive neurosurgery was thus avoided.

Which craniofacial fractures are associated with external auditory canal bleeding?

PURPOSE

External auditory canal bleeding (EACB) after facial trauma has been strongly associated with skull base fractures; however, EACB also can occur with other craniofacial fractures. The aim of this study was to analyze the frequency and causes of EACB in different craniofacial fracture types.

PATIENTS AND METHODS

The investigators used a retrospective cohort study design and enrolled a sample composed of patients with craniofacial fractures evaluated and treated from April 2006 through December 2011. The predictor variable was fracture type, which was categorized into 4 types: skull base fracture, midface fracture, and mandibular fracture with and without involvement of the condyle. The frequency of EACB among fracture types was compared with SPSS 13.0 (SPSS, Inc, Chicago, IL) and χ(2) test. Computed tomographic (CT) scans were analyzed to determine the cause of EACB.

RESULTS

EACB was found in 43 of 573 craniofacial fracture cases, with a frequency of 7.5%. There were 19 EACB sides in 123 skull base fracture cases (15.4%), 26 EACB sides in 150 mandibular fracture cases involving the 196 condyles (13.3%; of these 196 condyles, 92.3% were intracapsular condylar fractures [ICFs]), 2 EACB sides in 150 mandibular fracture cases not involving the condyle (1.3%), and 1 EACB case in 150 midface fracture cases (0.7%). Statistical analysis of EACB frequency for each fracture type showed a significant difference between skull base or mandibular fractures with condylar involvement and midface or mandibular fractures without condylar involvement (P < .05). However, there was no significant difference between skull base and mandibular fractures involving the condyle and midface fracture and mandibular fractures not involving the condyle (P > .05).

CONCLUSIONS

EACB is uncommon in craniofacial fractures. The frequency varies significantly based on fracture type. Skull base fracture and mandibular ICF are the 2 main causes of EACB.