The primary objective of the trial is to determine if intraoperative CT imaging improves clinical outcomes for zygomaticomaxillary complex and zygomatic arch fractures that are managed surgically. This will be assessed through the following variables:
- Post-operative radiographic reduction adequacy
- Need for revision surgery
- Number of intra-operative re-reductions
- Post-operative diplopia
- Facial profile restoration
- Surgical incision and scarring
The trial has a secondary objective to ascertain whether intraoperative CT imaging has a significant impact on length of surgery and whether it affects the outcomes of delayed versus early surgical treatment outcomes.15
This is a prospective, single centre, double-blinded, randomised controlled trial. It will be conducted by the oral and maxillofacial surgery department (OMFS) at the Royal Brisbane and Women’s Hospital in Brisbane (RBWH), Australia. This is a tertiary teaching hospital and major trauma centre for the city of Brisbane and the state of Queensland. The study was approved by the Royal Brisbane and Women’s Hospital Human Research Ethics Committee (reference number HREC/16/QRBW/18) on the 27th July 2016, prior to recruitment of patients. This study complies with the National Health and Medical Research Council’s (NHMRC) National Statement on Ethical Conduct in Human Research (2007). The trial was registered with the Australian and New Zealand Clinical Trials Registry (registration number ACTRN12616000693426) on the 26th May 2016 prior to patient recruitment. Please see the SPIRIT figure (Fig. 1) for an illustration of the timeline for enrolment, interventions and assessments of the trial. The SPIRIT checklist has been completed for further information (additional file 1).
If there is any alteration to the trial protocol that has been submitted to the RBWH Human Research Ethics Committee and the Australian and New Zealand Clinical Trials Registry, these organisations will be informed of the amendments immediately.
Recruitment and consent
All patients who present to the oral and maxillofacial surgery department of the RBWH, with an isolated zygomaticomaxillary complex fracture or an isolated zygomatic arch fracture, will be screened for a position on the trial. As RBWH is an adult hospital, all patients will be 16 years of age or older and they must require surgical management of their ZMC or ZA fracture to be included in the trial. Exclusion criteria from the trial includes the following:
- Pregnant women
- Patients who are unable to give informed consent
- Patients with concomitant non-zygomatic facial fractures (including orbital floor fractures) or bilateral zygomatic fractures
- Patients who do not wish to be part of the study
If a patient fulfils the criteria to participate in the trial, they will be informed verbally of what the trial involves, the risks associated with it and their role. They will also be given written information regarding the trial, risks involved and all of their rights, including the ability to withdraw at any stage. If the patient is happy to participate, they will be given a consent form to complete. The aforementioned tasks of obtaining informed consent and recruiting patients to the trial will be completed by an oral and maxillofacial surgery registrar (training surgeon) or consultant (surgeon).
The patients who are recruited to the trial will be randomised into two groups, intraoperative computed tomography scan (intervention) and no intraoperative computed tomography scan (control). The randomisation of the patient will be conducted by the oral and maxillofacial surgery department nurse, who will blindly select a table tennis ball from a container. The container will hold only two balls, with one ball having the word “intervention” and the other ball having the word “control” written on them. Whichever ball is selected by the nurse, is the group to which the patient is allocated.
The patients will not be informed of which group they are randomised to. Concurrently, the clinician assessing the radiographic reduction of the post-operative films will be blinded to which arm of the trial the patient has been allotted. The surgeon operating on the patient will not be blinded as this is impossible, given they will be witness to an intraoperative computed tomography scan being performed or not. The doctor assessing the patient in clinic at both one and six weeks post-surgery, will not be blinded to the group the patient has been apportioned. Blinding of this assessment would be extremely difficult as the doctor assessing the patient will be involved with the operation and hence know the allocated group. The clinician assessing the post-operative radiographic reduction will not perform any of the operations for the trial.
Study groups (control and intervention)
The intervention group of the study will undergo a computed tomography scan during their operation for their ZMC or ZA fracture. This scan occurs after the fracture has been opened, reduced and fixated or in the case of an isolated zygomatic arch fractured, opened and elevated. Once the scan has been completed the surgeon will review the scan and decide if the reduction is satisfactory. If they are satisfied with the reduction, the incisions will be closed and the operation completed. If there are inaccuracies with the reduction, the fixation equipment will be removed and the fractured adjusted to the correct position. It is then left to the discretion of the surgeon to decide if they wish to have another intraoperative CT scan performed or if they are satisfied with the reduction clinically. Once the surgery is completed, post-operative radiographs will be performed prior to the patient being discharged home. These radiographs will include a submental-vertex view (SMV), a posterior-anterior face (PA face) view and occipitomental 15 degree and 30 degree views (OM15 and OM30).
Patients in the control group will undergo their relevant surgery as normal but will not have any intraoperative imaging performed. After completion of the surgery, control groups patients will undergo the same post-operative radiographs as described for the intervention group above. No other concomitant care or interventions are prohibited during the trial.
Surgical incisions for both groups are identical for both groups but at the discretion of the operating surgeon. Direct access to fracture sites is via the upper blepharoplasty incision, subtarsal incision, or upper buccal sulcus transoral incision. Elevation is either via a “Gillies” temporal incision or upper buccal sulcus incision.
All procedures will be performed by, or under the direct in theatre supervision of one of three Oral and Maxillofacial Specialist surgeons. All three have extensive experience in the management of facial trauma with a minimum of three hundred zygomatic complex fractures each.
Follow-up and Outcomes
All patients within the trial will have post-operative SMV, PA face, OM15 and OM30 radiographs taken either on the day of surgery or the following day, prior to discharge. These radiographs will be assessed by a blinded oral and maxillofacial surgeon who will not be involved in any of the operations, pre or post-surgical clinical assessments. The reduction adequacy of the fractures will be based off of the radiographs and the quality of the reduction will be evaluated as “good”, “fair” or “poor”.
- Good: equivalent to premorbid
- Fair: minor discrepancy but unlikely to require reoperation
- Poor: major discrepancy, reoperation required
Patients in the trial who are undergoing ZMC open reduction and internal fixation will stay overnight in hospital and barring any complications, be discharged home day one post-surgery. Patients undergoing open reduction of their isolated zygomatic arch fracture will, unless there are any unforeseen complications, be discharged on the same day as surgery. All patients will be followed-up in the oral and maxillofacial surgery outpatient department at one and six weeks post-surgery. During these outpatient appointments, the registrar or consultant reviewing the patient will assess them for diplopia, surgical site scarring and facial profile restoration. These parameters will be graded by the OMFS registrar or consultant and their assessment will be recorded on a standardised form (Figure 2 and 3). The need for revision surgery at any timepoint until 3 months following the completion of the study and a number of other variables (see Figure 2 and 3 for a full list) will also be recorded on the form.
Data Collection, Management and Confidentiality
Data from the post-operative radiographic assessments will be entered directly into the trial excel spreadsheet. All data recorded on the postoperative assessment forms (Figure 2 and 3) will be transferred to the trial excel spreadsheet. This excel file will be stored on a single, password-protected personal computer. At the completion of the trial, the excel spreadsheet will be transferred to a password-protected computer within the oral and maxillofacial surgery department at the RBWH. It will be stored on this computer for 15 years. All physical copies of the consent and post-operative assessment forms will be stored in a designated trial folder, which will be stored in the OMFS department, in a locked room at the Royal Brisbane and Women’s Hospital. At the completion of the trial, this folder will remain in the OMFS department for 15 years. The final trial data set will only be accessible to the authors of the trial.
Patients names, date of birth, gender, address and occupation will not be included on any data being collected. Patients will only be identified by their unique record number (URN) otherwise known as a medical record or hospital record number. Prior to statistical analysis being performed, the URN’s will be removed from the data pool.
Patients are entitled to withdraw from the trial at any stage. Their withdrawal will have no implications for their ongoing management. Any patient who elects to withdraw, will have their trial data deleted and this will not be used in the statistical analysis.
If trial participants fail to attend their one or six week follow-up appointments, any data previously recorded for them, will be included in the trial data and analysed accordingly.
Evaluation of outcomes
A two sample t-test will be used for continuous variable analysis. A chi-square test will be used for categorical variable analysis and for all data, p-values of < 0.05 will be considered significant. The software program SPSS will be used for all statistical analysis. A subgroup analysis based on the severity of the fractures will also be conducted. Patients will be analysed as per their treatment but non adherence will be considered in the final presentation of data. An interim analysis will be also be undertaken. There are no other audits of trial conduct planned.
Any adverse outcomes involving trial participants such as surgical site infection, metalware infection, excessive bleeding, change in vision, death or common perioperative complications such as deep vein thrombosis, pulmonary embolism or pulmonary infections will be documented and treated accordingly. If warranted, referral to other medical specialist teams will be made. Post-trial care and compensation, if required, will be as per Queensland Health standard arrangements.
An estimated 200 patients will be required for a sample size that will produce significant results. This is based on two-sided testing with a power calculation of 80% and is established from local department outcome estimates and results from studies by Van Hout et al, Hurrell et al and Van Den Bergh et al.10,15,16 Post-operative radiographic reduction adequacy was the variable with the largest projected sample size necessary for a statistically significant result. The power calculation was performed by Dr Michael David, a biostatistician from the University of Queensland (UQ) School of Population Health.
Due to the low level of evidence available in the current literature, the sample size calculations may not be reliable and estimates were not possible for all variables being proposed in this study. Subsequently, a mid-study analysis will be conducted to more accurately assess the predicted sample size calculations. It is estimated that from the average number of yearly presentations of ZMC and ZA fractures at the RBWH, this study will take approximately 2 years to complete. If the mid-study analysis finds a statistically significant result, the study will potentially be terminated early. The decision to terminate the trial or continue after the mid-study analysis will be at the discretion of the study authors.
The standard practice for post-operative assessment following a ZMC or ZA fracture at the RBWH is for a patient to have four plain radiographs (OM15, OM30; PA face and SMV). Occasionally post-operative CT scans are ordered in-lieu of plain films. In this study, the interventional group will receive an intra-operative CT scan and the control group will not receive any intraoperative imaging. Both groups will have four plain radiographs taken post-operatively. It is estimated that the interventional group will receive 1.5millisieverts (mSv) and the control groups will receive 0.4mSv of ionising radiation. The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), a department of the Australian Government, estimates that a domestic airline pilot will be exposed to 2mSv of cosmic radiation per year.17 ARPANSA also states that there is “no direct evidence of human health effects” up to 10mSv of ionising radiation.17 As such, the increased dose of radiation to the interventional group is not considered harmful to the patient and by performing post-operative radiographs on both groups, blinding of the assessing surgeon is made possible. If the results of the study show that intraoperative CT scans should be used for ZMC/ZA fracture management, the need for post-operative imaging would be eliminated, thus reducing the radiation exposure further. This is supported by a paper published by Van Hout el all, which states that “intraoperative imaging rarely increased patient exposure to ionizing radiation as the intraoperative imaging obviates postoperative imaging.”10
The use of intraoperative CT scan in the interventional group, is likely to increase the overall operative time for these patients. It is estimated that intraoperative CT scan will increase the operation duration by ten minutes.