Isolated Fractures of the Posterior Maxillary Sinus: CT Appearance and Proposed Mechanism

Abstract

SUMMARY:A heretofore unreported type of facial fracture is discussed. Twenty-two cases of posterior maxillary wall fracture are reviewed, of which 59% demonstrated concomitant mandibular fracture. The proposed mechanism for this injury is an impact from the ipsilateral mandibular coronoid process striking the posterior maxillary wall, with associated mandibular dislocation or fracture. As such, further investigation of the mandible may be warranted when this type of maxillary wall fracture is encountered to exclude concomitant injury.ABBREVIATIONS: GSW ϭ gunshot wound; MVC ϭ motor vehicle crash; TMJ ϭ temporomandibular joint H igh-resolution CT with multiplanar reformats and 3D postprocessing has become a standard part of the assessment of facial trauma because of the exquisite sensitivity of this imaging technique for fracture. Such sensitivity for fracture is particularly relevant in the setting of facial trauma, given that soft-tissue swelling can mask underlying fractures on physical examination.1,2 Accurate fracture detection and characterization are important because facial fractures can have long-term functional and/or cosmetic sequelae.3 Extensive work, therefore, has been invested in describing patterns and underlying mechanisms of facial fracture.4-7 Data regarding specific patterns and mechanisms of fracture can be helpful to the radiologist by increasing the sensitivity for detection of distributed injuries in which 1 traumatic finding leads to a focused search for related injuries. [4][5][6][7] In this retrospective case series, we describe a unique type of fracture characterized by an isolated one of the posterior maxillary wall and its association with mandibular dislocation and/or fracture. The proposed mechanism for this specific injury is also discussed. Materials and MethodsWe performed a retrospective review of the neuroradiology section case log from 2002 to 2009, searching for patients with the CT (either head or face CT) diagnosis of maxilla fracture limited to the posterior wall, including a possible associated mandibular fracture. All patients had been imaged in the setting of trauma by using single-section or multidetector CT scanners with 1, 4, 16, and 64 detectors (LightSpeed VCT; GE Healthcare, Milwaukee, Wisconsin). Axial CT images were generally obtained via the following parameters: 0.625-mm section thickness (3-mm thickness in old scanners), 1.375:1 pitch, 120 kV, 540 mA, no gantry tilt, 20 display FOVs, and a bone reconstruction algorithm. Multiplanar reconstruction was performed in most of the fractures, and 3D postprocessing was performed in recent years by using AquariusNET software (TeraRecon, San Mateo, California) to aid in the diagnosis and to exclude other fractures. All CT scans were reviewed independently by 2 neuroradiologists to determine if the patient had a fracture of the maxilla limited to the posterior wall as well as a concomitant fracture and/or dislocation of the mandible. Medical records of each patient were reviewed for clinical history and confirmation of ...

Computed Tomography evaluation of maxillofacial injuries

“…They are commonly associated with ipsilateral mandibular fractures and may involve TMJ. 19 In our study maxilla and maxillary sinus fractures were the commonest fractures accounting for 36% of cases. The mode of injury was RTA.…”

Characteristic Multidetector Computed Tomography Findings of Maxillofacial Fractures Resulting from Falls in the Elderly

“…Multidetector computed tomography (MDCT) with multiplanar reformation (MPR) and three-dimensional (3D) images has become a standard part of the assessment of facial injury because of the exquisite sensitivity of this imaging technique for fracture (9)(10)(11)(12). However, to our knowledge, characteristic MDCT findings of maxillofacial fractures resulting from falls in the elderly have not been reported in the literature.…”

Fractures of the posterolateral maxillary sinus: a masticator space blowout injury?

“…The majority of these were nasal fractures, although fractures of the maxillary bones accounted for nearly 14 % [2]. Despite the frequency of maxillary fractures, isolated fractures of the posterolateral maxillary sinus have been only described recently [1]. In describing the fracture, the authors hypothesized that the fracture was caused by a direct impact of the coronoid process on the posterolateral maxillary sinus.…”

“…Fractures of the posterolateral maxillary sinus have been described in association with mandibular fractures with a hypothesized mechanism of direct impaction of the coronoid process on the maxillary sinus [1]. In our clinical practice, we have observed this fracture with other regional fractures and hypothesize that this fracture is due to a transient elevation in pressure in the masticator space resulting in a blowout type injury.…”