Reoperative midface trauma

Finite Element Analysis of 2- and 3-Point Internal Fixation Methods for the Treatment of Zygomaticomaxillary Complex Fracture

Open reduction followed by internal fixation (ORIF) has been regarded as the most effective technique for surgical repair of zygomaticomaxillary complex (ZMC) fractures. However, the ideal internal fixation method to achieve stable reduction remains controversial. This research aims to assess and compare the stability of the 2- and 3-point screw-plate fixation methods using finite element method (FEM). Based on computed tomography (CT), the finite element models of 2-point (ZFS + IOR) and 3-point (ZFS + IOR + ZMB) fixation for isolated displaced ZMC fracture were reconstructed. The force of 120 N was applied to the models to simulate the masseter muscle strength. The maximum stress and displacement of the 2 models were measured to compare the stability. Two geometrically accurate and finite element models were reconstructed successfully. In both the 2- and 3-point fixation models, the maximum stress was significantly lower than the mechanical properties of pure titanium and titanium alloys and the maximum displacement was ≤0.1 mm. The results of this study suggested that both 2- and 3-point fixation of isolated displaced ZMC fractures provide good stability. The FEM innovatively applied in this study can not only show the biomechanical properties of the orbital skeleton and masseter muscle but also assess the stability of the two fixation methods and provide a theoretical reference. This study verifies the effectiveness of 2-point fixation and combined with the clinical benefits of reduced incisions, shorter operative time and lower cost, make this an attractive method.

A study protocol for a randomised controlled trial evaluating the effects of intraoperative computed tomography on the outcomes of zygomatic fractures

Background

Zygomaticomaxillary complex (ZMC) and zygomatic arch (ZA) fractures are common injuries resulting from facial trauma and frequently require surgical management (Huang et al., Craniomaxillofac Trauma Reconstr 8(4):271-6, 2015). A substantial number of post-operative functional and cosmetic complications can arise from the surgical management of these fractures. These include scarring, inadequate facial profile restoration, facial asymmetries and diplopia (Ellis et al. J Oral Maxillofac Surg 54(4):386-400, 1996; Yang et al. Oral Maxillofac Surg Clin North Am 23(1):31-45, 2011; Kloss et al. Int J Oral Maxillofac Surg 40(1):33-7, 2011). Intuitively, most of these aforementioned complications arise as a result of inadequate fracture reduction; however, current standard practice is to assess reduction post-operatively through plain radiographs or computed tomography (CT) scans. The role of intra-operative CT scanning to assess the reduction of ZMC/ZA fractures and the potential impact on complications, has thus far not been established.

Methods

This is a prospective randomised controlled trial currently being undertaken at the Royal Brisbane and Women’s Hospital. All patients who require operative management of their ZMC or ZA fractures are offered enrollment in the trial. The patients are randomised into two groups: interventional (intra-operative CT) and control (no intra-operative CT). All patients in each group will have post-operative radiographs taken. From these radiographs, the reduction of the ZMC and/or ZA fracture is graded by a blinded assessor. Patients will be reviewed in clinic at 1 week and 6 weeks post-surgery. During these consultations, all patients will be assessed for scarring, diplopia, facial profile restoration and need for revision surgery.

Discussion

Many complications associated with surgical management of ZMC and ZA fractures involve poor aesthetic results as a direct consequence of inadequate fracture reduction. Inadequate fracture reduction is predictable given that small incisions are used and only limited visualisation of the fractures is possible during the procedure. This is due to a desire to limit scarring and reduce the risk of damage to vital structures in an aesthetically sensitive region of the body. It follows that an intraoperative adjunctive tool such as a CT scan, which can assist in visualisation of the fractures and the subsequent reduction, could potentially improve reduction and reduce complications.

Trial registration

Australian New Zealand Clinical Trials Registry, ACTRN12616000693426. Registered on 26 May 2016.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3625-8) contains supplementary material, which is available to authorized users.

Complete Reoperation in Orthognathic Surgery

BACKGROUND

Complete reoperation is defined as undergoing reoperative/repeated jaw osteotomies, in a patient who previously underwent orthognathic surgery. The purpose of this study is to (1) describe jaw positions at three time-points (before primary and before and after reoperative surgery), (2) investigate factors necessitating reoperation, and (3) outline the technical challenges.

METHODS

Repeated orthognathic surgery cases >1-year out were included. Demographic, radiologic, and perioperative data were compiled. Repeated osteotomies (Le-Fort and/or bilateral split sagittal osteotomy, with or without genioplasty), were compared to their respective primary procedures. Statistical analysis was performed using t tests and z-scores.

RESULTS

Fifteen patients were included (28.1 years; 71 percent female). Reoperative/repeated surgery was most often needed to address iatrogenic bony malposition and asymmetry. Relapse was a less common indication. Time between reoperative and primary surgery was 14 months. Sagittal discrepancies (p = 0.029) were the most frequent reason for primary orthognathic surgery (e.g., mandibular hypoplasia (p = 0.023). Reoperative/repeated orthognathic was performed for asymmetry (p = 0.014). Repeated procedures used more 3-dimensional planning (p < 0.001), required all three osteotomies (p = 0.034), had longer operative times (p = 0.078), and all required hardware removal (p < 0.001). Anatomical outcomes were good with 100% patient satisfaction at long-term follow-up.

CONCLUSIONS

Reoperative/repeated orthognathic surgery is challenging and underreported in the literature. Whereas primary orthognathic typically addressed sagittal discrepancies, reoperative/repeated osteotomies were needed to correct iatrogenic bone malposition and asymmetries. Challenges include: re-planning, scar burden, need to remove integrated hardware, and repeated osteotomy/fixation. Despite these difficulties, outcomes and patient acceptance were good.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

[Maxillofacial fractures: midface and internal orbit. Part 2: therapeutic options]

While the state of the art of clinical assessment and imaging techniques were described in Part 1, this contribution presents a systematic review of the surgical treatment principles in the management of midface and internal orbit fractures from initial care to definitive treatment, including illustrative case examples. New developments and advances are characterized by limited versus extended surgical approaches, by standardization of osteosynthesis principles with regard to three-dimensional buttress reconstruction, by newly developed individualized implants such as titanium meshes and, especially for complex fracture patterns, by critical assessment of anatomical reconstruction through intraoperative endoscopy, as well as intraoperative and postoperative imaging. Newly developed resorbable soft tissue anchors can be used both for ligament and soft tissue resuspension in order to reduce ptosis effects in the cheeks and nasolabial area to achieve facial aesthetics similar to those prior to the injury.