Abstract
Purpose
To determine the feasibility and efficacy of intraoperative ultrasound imaging in maxillofacial surgery of depressed zygomatic arch fractures. To ensure the accurate and adequate reduction of the depressed zygomatic arch using high frequency ultrasound linear probe and provide a reproducible technique.
Methods
The authors evaluated 10 consecutive adult patients with zygomatic arch fractures who required a closed reduction of the fractured zygomatic arch between January 2019 and June 2020. The fractures were diagnosed with a CT scan and clinical findings of reduced mouth opening with visible depression were the most common indication. Intraoperative Ultrasound imaging was used for our patients who underwent closed surgical reduction of zygomatic arch fractures to visualize and confirm accurate reduction. Postoperative CT scan was done to evaluate the reduction.
Results
An intraoral approach was used to reduce the fractures with an elevator. In Nine cases the achieved reduction was a mirror image of the contralateral unfractured arch as evaluated with postoperative CT scan. In One case the posterior third of arch was found to be minimally displaced. Mouth opening and facial symmetry were improved and satisfactory in all the cases.
Conclusions
Intraoperative ultrasound assisted reduction of zygomatic arch improves the assessment of reduction and provides real time feedback to the surgeon. The results are promising and this modality is recommended for similar cases.
Highlights
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Blind reduction of zygomatic arch fractures may end with unsatisfactory outcomes.
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Intraoperative imaging with ultrasound allows real time visual feedback to the surgeon.
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Multiple attempts at reduction under ultrasound guidance results in better radiometric reduction.
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Ultrasound is an easy to learn technique as shown in the video.
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Ultrasound is portable, small, cheap, nonionizing and universally available.
1
Introduction
Zygomatic arch fractures have historically been treated with blind closed reduction and it is the most widely used method [ , ]. The contour of the zygomatic arch reflects the relationship of the zygomatic bone to the skull base and it is the most reliable indicator for the anterior projection of the zygoma. Accurate anatomical reduction of the zygomatic arch is a mainstay in the alignment of zygomatic complex, midface and panfacial fractures [ ]. The inadequate reduction of the zygomatic arch itself might lead to a visible depression of the overlying soft tissues, and the zygomatic arch might interfere with the mandibular coronoid process resulting in limitation of mouth opening. Finally, an incomplete reposition might be unstable and bears the risk of loss of reduction which might require reoperation [ , ].
Computed tomography (CT) has become the gold standard for the diagnosis and radiological followup of maxillofacial injuries [ ]. Up until now, it has only been possible to monitor the alignment of zygomatic arch fractures postoperatively with a CT examination with axial sectioning. Incorrect positioning may require reoperations or, eventually, cause unsatisfactory functional and cosmetic results. Intraoperative imaging allows the visualization of fracture morphology that provides, in real time, a guide for surgical decision making. Although various intraoperative imaging modalities like CBCT, C-arm Fluoroscopy and O-arm have been reported in maxillofacial surgeries, most of them are expensive, cumbersome, carry a radiation risk and require a steep learning curve thus making them less feasible for use in simpler fracture scenarios [ ]. Ultrasound is cheap, easily available, nonionizing and requires a fairly easy learning curve. Intraoperative ultrasound can provide a relatively feasible and efficient alternative to the blind reduction technique of zygomatic arch reduction.
The purpose of this case series is to present the accuracy and efficacy of ultrasound imaging in patients with depressed zygomatic arch fractures that require surgical management.
2
Material and methods
We studied 10 consecutive adult patients with depressed zygomatic arch fractures between January 2019 and June 2020. They underwent closed reduction of the zygomatic arch using intraoperative ultrasound imaging and we have illustrated the technique and surgical video of a case. A single surgical team, with two experienced maxillofacial surgeons, performed all surgeries. Patients included in the study agreed and signed a consent to use intraoperative ultrasound imaging and surgical procedure simultaneously. Patient demographics, operative details, outcomes and complications were recorded.
SamsungMysonoU6 linear probe capable of Musculoskeletal imaging was used in b mode for visualization and location of the fracture. Radiographic continuity of periosteal shadow without any step was taken as the endpoint for reduction and the procedure. All the operation was performed under general anaesthesia through an intraoral approach and a flat handle of the elevator was used for reduction. Post-operative CT scan was acquired on day 1 after operation and Patients were discharged on the same day. The followup was planned after 7 days for the evaluation of mouth opening and assessment of facial symmetry. Radiometric measurement for accuracy of reduction was performed by a standardized method. On the followup, patients were asked to report on facial asymmetry as satisfactory or unsatisfactory. They were also asked to report on mouth opening and masticatory ability as satisfactory or unsatisfactory.
3
The surgical technique with an illustrative case
A 37-year-old male with reduced and painful mouth opening after enduring an RTA presented to the unit. CT scan of the facial bone confirmed a depressed fracture of the right zygomatic arch. There was a visible depression in the middle of the arch. The ultrasound linear probe was used to visualize the fracture which appears as an “M” shaped echogenic line on the monitor. Once the midline of the linear probe, the midline of the “M” shaped shadow of the fracture and the monitor were aligned Intraoperatively, we marked the position of the probe with a delible marker to reproduce the probe’s position on the fracture. The elevator was introduced below the arch and the traditional upward and outward force were delivered to elevate the arch. ( Fig. 1 ). The linear probe was repositioned on the marked point and the echogenic line was visualized on the monitor. Further attempts at elevation were continued till a linear echogenic line was visible on the monitor ( Fig. 2 ) at which point the reduction was considered adequate and the procedure was terminated. No splints were used on the arch, but the patients were advised not to sleep or put pressure on that side of the face for a week. The complete technique is presented in the short video file (Video 1).
